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Simultaneous Visible Light Communication and Ranging Using High-Speed Stereo Cameras Based on Bicubic Interpolation Considering Multi-Level Pulse-Width Modulation
- R. Huang, M. Kinoshita, T. Yamazato, H. Okada, K. Kamakura, S. Arai, T. Yendo, T. Fujii
- IEICE Transactions on Fundamentals
- 2023幎7æ
- Visible light communication (VLC) and visible light ranging are applicable techniques for intelligent transportation systems (ITS). They use every unique light-emitting diode (LED) on roads for data transmission and range estimation. The simultaneous VLC and ranging can be applied to improve the performance of both. It is necessary to achieve rapid data rate and high-accuracy ranging when transmitting VLC data and estimating the range simultaneously. We use the signal modulation method of pulse-width modulation (PWM) to increase the data rate. However, when using PWM for VLC data transmission, images of the LED transmitters are captured at different luminance levels and are easily saturated, and LED saturation leads to inaccurate range estimation. In this paper, we establish a novel simultaneous visible light communication and ranging system for ITS using PWM. Here, we analyze the LED saturation problems and apply bicubic interpolation to solve the LED saturation problem and thus, improve the communication and ranging performance. Simultaneous communication and ranging are enabled using a stereo camera. Communication is realized using maximal-ratio combining (MRC) while ranging is achieved using phase-only correlation (POC) and sinc function approximation. Furthermore, we measured the performance of our proposed system using a field trial experiment. The results show that error-free performance can be achieved up to a communication distance of 55 m and the range estimation errors are below 0.5 m within 60 m.
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- 2022幎12æ
- ã€ã¡ãŒãžã»ã³ãµéä¿¡ïŒImage sensor communication: ISCïŒã¯CMOSã€ã¡ãŒãžã»ã³ãµãªã©ã®äºæ¬¡å
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An Experimental Study on A Noise-aided 1-bit ADC Receiver for 4-PAM
- J. Zheng, T. Yamazato, M. Saito
- IEICE Communications Express, vol.11, no.12, pp.817-822
- 2022幎12æ
- DOI:10.1587/comex.2022COL0032
- 1-bit analog-to-digital converters (ADCs) have low power consumption and can easily speed up the analog-to-digital conversion and sampling. However, due to their resolution of only 1 bit, the nonlinearity between the input with multiple amplitude levels and output is large. With the method of utilizing noise proposed in previous studies, 1-bit ADCs can be linearized to demodulate signals with multi-level amplitude modulation like pulse amplitude modulation (PAM) and quadrature amplitude modulation (QAM). In this letter, we construct a receiver circuit using a 1-bit ADC, evaluate its performance, and show its availability through demodulation experiments on 4-PAM signals.
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- 2022幎12æ
- DOI:10.14923/transcomj.2022JBP3008
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Position estimation method using recursive MAP estimation for ultrasonic sensor arrays
- M. Hattori, A. Tsujii, T. Kasashima, H. Hatano, T. Yamazato
- International Conference on Emerging Technologies for Communications (ICETC), O5-5, Waseda University
- 2022幎12æ
- We are working on the measurement of obstacle positions by an ultrasonic sensor array. This paper proposes a recursive position estimation method using signals from eight ultrasonic sensors forming a linear array. First, we estimate the distance to the obstacle from the time difference between the eight received signals. Then, assuming that the ranging error follows a Gaussian distribution and that each of the eight ranging values is independent, we can get the existence probability of the obstacle's position by a pair of two obtained distances. Finally, we estimate the position of the obstacle by multiplying 28 (8C2) existence probabilities obtained. The conventional method estimates the position of an obstacle by the above procedure. However, the estimation accuracy in the angular direction was poor, resulting in the spread of the existence probability in the horizontal direction. In the proposed recursive position estimation, we obtain the existence probability of an obstacle by the procedure shown above, and then use it as the prior probability of the obstacle's estimated position. Furthermore, we recursively perform the same process to obtain the existence probability of the obstacle. In this way, we improve the accuracy of the estimation of the position of the obstacle by the existence probability. We present the experiment results to show the effectiveness of the proposed method.
Influence of Walsh-Hadamard Code Sequency in Visible Light Communication Using an Event Camera
- D. Ehara, Z. Tang, M. Kinoshita, T. Yamazato, H. Okada, K. Kamakura, S. Arai, T. Yendo, T. Fujii
- International Conference on Emerging Technologies for Communications (ICETC), S9-5, Tokyo
- 2022幎12æ
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- 2022幎9æ
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- 2022幎9æ
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- 2022幎9æ
Roadside LED Array Acquisition For Road-to-Vehicle Visible Light Communication Using Spatial-Temporal Gradient Values
- K. Nakamura, R. Huang, T. Yamazato, M. Kinoshita, K. Kamakura, S. Arai, T. Yendo, T. Fujii
- IEICE Communications Express, vol.X11-B, no.8, pp. -
- 2022幎8æ
- https://doi.org/10.1587/comex.2022TCL0008
- Most of the previous research on the acquisition of the LED Array transmitter assumes that the onboard receiver approaches the LED transmitter from the carâs front. In this study, we considered a case where the vehicleâs receiver crosses the LED transmitter. This letter modifies the algorithm using spatial-temporal gradient values to detect LED arrays. As a result, we achieved error-free acquisition and successfully communicated up to 9728 [bits] at a vehicle speed of 25 [km/h].
Visible Light Communication System Using Rolling Shutter Image Sensor for ITS
- S. Kamiya, Z. Tang, T. Yamazato,
- IEEE ICC Workshop on Optical Wireless Communications (OWC), Seoul, South Korea
- 2022幎5æ
- In this study, we investigate the application of visible light communication (VLC) to intelligent transport systems (ITS) using rolling shutter image sensors as receivers. The use of a global shutter high-speed image sensor as a receiver has been widely examined in ITS-VLC so far. However, this image sensor is impractical for general-purpose applications due to the high cost. This study aims to perform ITS-VLC using the rolling shutter image sensor. The rolling shutter image sensor is widely used in the smartphone camera. By using it as a receiver, ITS-VLC can be used in more opportunities. In this study, we propose a ITSVLC system using rolling shutter image sensor. The proposed system demodulates data from images captured in a moving environment. We evaluate the communication performance by measuring the bit error rate for the ITS-VLC experiments.
A Preliminary Investigation For Event Camera-Based Visible Light Communication Using The Propeller-type Rotary LED Transmitter
- Z. Tang,T. Yamazato, S. Arai
- IEEE ICC Workshop on Optical Wireless Communications (OWC), Seoul, South Korea
- 2022幎5æ
- This study investigates a new communication scheme for the event camera-based visible light communication (VLC) using a propeller-type rotary LED transmitter. Conventional camera-based VLC suffers from low data rates and high latency due to the limited camera frame rates. To solve this problem, the event camera has been used as the receiver in VLC. Event cameras detect changes in brightness and asynchronously output these changes as events in microsecond order. The high temporal resolution gives the event camera-based VLC good potential in terms of high speed and low latency. However, when an event camera is used as the VLC receiver, the light of the transmitter needs to be changed constantly. If the transmitter LED is continuously in the same blinking state, the event camera may not output any events and the data could not be recovered until the blinking state changes. To transmit the optical signal for event cameras, we use a propeller-type rotary LED transmitter for the event camera-based VLC. The transmitter rotates the blinking LED in circles and uses the afterimage of LED light to transmit signals. The event camera detects the afterimages and constantly outputs them as a stream of events. We filter the noise events and recover data using signal events. This study verifies the operation for the proposed system through an implementation experiment. As a result, we achieved the communication in the proposed system and provided a basic evaluation in terms of communication speed and quality.
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- 2022幎3æ
Simplified Alamouti-Type Space-Time Coding for Image Sensor Communication Using Rotary LED Transmitter
- Z. Tang, S. Arai, T. Yamazato
- IEEE Photonics Journal, vol. 14, no. 1, pp. 1-7
- 2022幎2æ
- https://doi.org/10.1109/JPHOT.2021.3137601
- This study proposes a simplified Alamouti-type space-time coding (STC), improving the performance of image sensor communication (ISC) using a rotary LED transmitter. The rotary LED transmitter was developed to increase the data rate of ISC using afterimages of LED lights. The transmitter simultaneously causes the LEDs to blink and rotates them around a vertical axis. Owing to the movement of the blinking LEDs that occurs within the exposure time of the camera, multiple blinking states are captured as afterimages, thus increasing the amount of information that can be received per image. However, with increasing communication distance, the size of the LED light captured on the image sensor decreases. In this case, it is difficult to distinguish each LED blinking state, leading to a degradation of the demodulation performance. To overcome this problem, the proposed STC encodes adjacent angular afterimages as symbol pairs and transmits these symbol pairs using two symbol times. In addition, we simplified the data decoding process by using normalized LED luminance values. We evaluate the demodulation performance of the proposed method through experiments. Compared with conventional coding methods, the proposed STC requires no channel estimation and significantly improves the demodulation performance.
Performance Enhancement of Rolling Shutter Based Visible Light Communication via Selective Reception Using Dual Cameras
LED array acquisition in Road to Vehicle Visible Light Communication when receiver crosses transmitter,International Conference on Emerging Technologies for Communications (ICETC)
- K. Nakamura, T. Yamazato, M. Kinoshita, K. Kamakura, S. Arai, T. Yendo, T. Fujii
- online"
- 2021幎12æ
- https://doi.org/10.34385/proc.68.B3-5
- Intelligent Transport Systems Visible Light Communication (ITS-VLC) is attracting significant attention as a solution to solve various problems that vehicles have, or for the installation of new systems in the vehicles. In ITS-VLC, the acquisition of the VLC transmitter via light-emitting diodes (LEDs) in the onboard cameraâs captured image is the first and essential step when receiving the VLC signal. Most of the previous research on the acquisition of the LEDs assumes that the vehicles approach the LEDs source from the front of the vehicle. However, there are many situations in which vehicles cross the LEDs. In this study, we considered a case in which the vehicleâs receiver crosses the LED transmitter. We modified the acquisition algorithm based on the spatial-temporal gradient utilized in our model in which the transmitter and the receiver cross each other. We found that we can acquire the transmitter by correcting the difference of the transmitterâs position in the captured image. When validating the specific signal, we achieved 100% acquisition success rate.
WWRF46 Panel Session
- T. Yamazato
- Wireless World Research Forum Meeting 46, Paris, France
- 2021幎12æ
- Optical wireless communication has been around since the 1980s. Why has its time come now in 5G/6G? What is the change?
Experimental Verification of 4-ary Pulse Amplitude Modulated Signal Receiver with Noise-added One-bit Analogue-to-digital Converter
- T. Ohtaguro, M. Saito, T. Yamazato
- International Conference on Materials and Systems for Sustainability (ICMaSS), online
- 2021幎11æ
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å ±éä¿¡åŠäŒè«æèª, vol.J104-B, no.11, pp.938-948
- 2021幎11æ
- https://doi.org/10.14923/transcomj.2021JBP3004
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- 倧ç°é»ææïŒéœè€å°äººïŒå±±éæ¬ä¹
- 驿°çç¡ç·éä¿¡æè¡ã«é¢ããæšªæåç ç©¶äŒ(MIKA), é£èŠ/ãªã³ã©ã€ã³
- 2021幎10æ
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- 山鿬ä¹ïŒèäºäŒžå€ªéïŒæšäžé
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- é»åæ
å ±éä¿¡åŠäŒ éä¿¡ãœãµã€ãšãã£å€§äŒ, BI-5-5, pp.SS-69 - SS-70, ãªã³ã©ã€ã³
- 2021幎9æ
Comparison of Distance Performances of Modulation Schemes in Intelligent Transport System Image Sensor Communication
- T. Yamamoto, T. Yamazato, H, Okada, M. Kinoshita, K. Kamakura, S. Arai, T. Yendo, T. Fujii
- IEICE Communications Express, vol.10, no.8, pp.498-504
- 2021幎8æ
- https://doi.org/10.1587/comex.2021ETL0032
- This study describes intelligent transport image sensor communication (ITS-ISC) systems that use LED arrays as transmitters that imitate traffic lights. Three signal-transmission schemes -luminance modulation, spatial modulation, and combined luminance and spatial modulation- use LED array. However, their suitability for ITS-ISC has not been explored yet. Therefore, we compare the communication performance of these three systems under strong saturation and present the results.
ãã¹ã¿ãŒè¬æŒïŒœã€ãã³ãã«ã¡ã©ãçšããLEDå¯èŠå
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- 倧平ç¥çïŒåéç¥åïŒå±±éæ¬ä¹ïŒèäºäŒžå€ªé
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, WBS2021-25, pp.19-23, ãªã³ã©ã€ã³
- 2021幎7æ
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- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, WBS2021-29, pp.39-44, ãªã³ã©ã€ã³
- 2021幎7æ
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- é»çæ¡, 山鿬ä¹, 岡ç°å, æšäžé
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- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, CS2021-22, pp.33-37, å±ä¹
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- 2021幎7æ
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- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, CS2021-15, pp.9-14, ãªã³ã©ã€ã³
- 2021幎7æ
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- 髿©çŽçŸïŒéåæµ©å£ïŒæšäžé
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- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, CS2021-20, pp.25-30, ãªã³ã©ã€ã³
- 2021幎7æ
Vehicle Distance Measurement based on Visible Light Communication Using Stereo Cameras
- R. Huang, T. Yamazato, M. Kinoshita, H. Okada, K. Kamakura, S. Arai, T. Yendo, T. Fujii
- IEEE Intelligent Vehicles Symposium, Nagoya, Japan
- 2021幎7æ
- https://doi.org/10.1109/IV48863.2021.9575534
- Visible light communication based intelligent transportation systems (ITS-VLC) show great potential for future urban mobility. This study presents a performance evaluation of range estimation between vehicles and infrastructures in an ITS-VLC system. In the proposed ITS-VLC system, it is easy to simultaneously conduct communication and ranging using stereo cameras. However, the stereo camera calibration becomes a problem during simultaneous communication and ranging due to vehicle vibration. Using the data from LED transmitters and stereo cameras, it can obtain multiple measurements of distance. The monocular-stereo fusion algorithm is applied to visible light ranging in the proposed scheme using particle swarm optimization. We employed real data from the field trial experiment and achieved a ranging accuracy of 60±1.0 m.
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- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, ITS2021-1, pp.1-6, ãªã³ã©ã€ã³
- 2021幎7æ
Method for considering angle error in the position estimation of a moving target using ultrasonic array
- M. Hattori, A. Tsujii, T. Kasashima, H. Hatano, T.Yamazato
- IEICE Communications Express, vol.10, no.7, pp.374-379
- 2021幎7æ
- https://doi.org/10.1587/comex.2021XBL0088
- In this study, we propose a method for reducing angle error in position estimation of a moving target. The distance between the transmitting array and target is approximated by two receiving sensors close to the transmitting array. This enables more accurate distance measurement between the receiving sensor and the target.
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- ç¥è°·å³»èŒïŒå±±éæ¬ä¹ïŒå²¡ç°åïŒ è€äºä¿åœ°ïŒæšäžé
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å ±éä¿¡åŠäŒæè¡ç ç©¶å ±åïŒRCS2021-52, pp.139-144, ãªã³ã©ã€ã³
- 2021幎6æ
- æ¬çš¿ã§ã¯ã€ã¡ãŒãžã»ã³ãµãåä¿¡æ©ã«çšããå¯èŠå
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éä¿¡ã§ã¯åä¿¡æ©ã«ã°ããŒãã«ã·ã£ãã¿ æ¹åŒã€ã¡ãŒãžã»ã³ãµã䜿çšããããšãåºãæ€èšãããŠããïŒããããã®ã€ã¡ãŒãžã»ã³ãµã¯é«äŸ¡ãªã©ã®çç±ããçŸåšäžè¬çã«æ®åããŠããªãïŒããã§æ¬çš¿ã§ã¯ããŒãªã³ã°ã·ã£ãã¿æ¹åŒã€ã¡ãŒãžã»ã³ãµãçšããITS å¯èŠå
éä¿¡ã®åææ€èšãè¡ãïŒããŒãªã³ã°ã·ã£ãã¿æ¹åŒã¯ã¹ããŒããã©ã³ã«ãæèŒãããŠãããã®ã§ããïŒãããåä¿¡æ©ãšããŠäœ¿ãããšã§ããå€ãã®æ©äŒã§ITS å¯èŠå
éä¿¡ã䜿çšå¯èœãšãªãïŒä»åã¯çè·é¢éæ¢ç°å¢äžã«ãããŠéä¿¡æ©ã«LED ã¢ã¬ã€ïŒåä¿¡æ©ã«ããŒãªã³ã°ã·ã£ãã¿æ¹åŒã€ã¡ãŒãžã»ã³ãµãçšããéä¿¡ã·ã¹ãã ãæ§ç¯ãïŒæ®åœ±å®éšãè¡ã£ãŠé²å
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éé³ãçšãã1bit ADCã«ãã4å€PAMä¿¡å·ã®åŸ©èª¿æ³ã«é¢ããå®éšçæ€èš
- 倧ç°é»ææïŒéœè€å°äººïŒå±±éæ¬ä¹
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, RCS2021-51, pp.133-138, ãªã³ã©ã€ã³
- 2021幎6æ
Circuit Experiment of Photodiode-Type Visible Light Communication Using the Stochastic Resonance Generated by Interfering Light Noise
- S. Arai, W. Tamura, T. Yamazato, H. Hatano, M. Saito, H. Tanaka, and Y. Tadokoro
- IEEE International Symposium on Circuits and Systems (ISCAS), pp. 1-5, Daegu, Korea (On-site & Virtual)
- 2021幎5æ
- https://doi.org/10.1109/ISCAS51556.2021.9401452
- This study focuses on visible light communication (VLC) using a photodiode as a receiver. Accurate data transmission by this type of VLC is a challenge because the photodiode cannot detect weak light of subthreshold intensity owing to its insufficient light sensitivity. To overcome this problem, we employ a stochastic resonance, which is a nonlinear phenomenon in which the response characteristics of a system improve as its noise intensity increases, for the receiver of this VLC system. We also employ additive light-emitting diode light, which interferes in the photodiode as intentional noise. As an experimental result, the stochastic resonance was achieved by setting the parameters of the noise source appropriately, and we recovered the weak transmitting signal at the receiver.
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- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, A-9-3, p.88, ãªã³ã©ã€ã³
- 2021幎3æ
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éé³ãš1bit ADCãçšãããã«ãã¢ã³ããåä¿¡æ©ã«ããããã£ãã«æšå®ãšä¿¡å·åŸ©èª¿
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å ±éä¿¡åŠäŒ ç·å倧äŒ, B-8-27, p.148, ãªã³ã©ã€ã³
- 2021幎3æ
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- åæ£åŒ·ïŒèäºäŒžå€ªéïŒå±±éæ¬ä¹
- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, A-9-4, p.89, ãªã³ã©ã€ã³
- 2021幎3æ
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- é»åæ
å ±éä¿¡åŠäŒæ±æµ·æ¯éšåæ¥ç ç©¶çºè¡šäŒ, 2-2, ãªã³ã©ã€ã³
- 2021幎3æ
ããŒãªã³ã°ã·ã£ãã¿æ¹åŒã€ã¡ãŒãžã»ã³ãµãçšããITSå¯èŠå
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- ç¥è°·å³»èŒ
- é»åæ
å ±éä¿¡åŠäŒæ±æµ·æ¯éšåæ¥ç ç©¶çºè¡šäŒ, 2-7, ãªã³ã©ã€ã³
- 2021幎3æ
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- åæ£åŒ·ïŒèäºäŒžå€ªéïŒå±±éæ¬ä¹
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, WBS2020-44, pp.86-91, ãªã³ã©ã€ã³
- 2021幎3æ
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- èšæšå€§ç©ºïŒæžçææµ·ïŒå±±å£é§¿ïŒæšäžé
ä¹ïŒéåæµ©å£ïŒå±±éæ¬ä¹
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, WBS2020-48, pp.110-114, ãªã³ã©ã€ã³
- 2021幎3æ
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è¬æŒïŒœè€æ°äœè»éè¡æãçšããLEO-MIMOäŒéæ¹åŒã®æ€èš
- äºè€å€§ä»ïŒå±±äžå²æŽïŒå±±éæ¬ä¹ïŒæ¡¶éæ€ïŒæŽå±±å€§æš¹ïŒç³žå·å代圊
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, SAT2020-36, p.41, ãªã³ã©ã€ã³
- 2021幎2æ
Optical Wireless Communication: A Candidate 6G Technology?
- S. Arai, M. Kinoshita, T. Yamazato
- IEICE Transactions on Fundamentals, vol.E104-A , no.1, pp.227-234
- 2021幎1æ
- https://doi.org/10.1587/transfun.2020WBI0001
- We discuss herein whether an optical wireless communication (OWC) system can be a candidate for post 5G or 6G cellular communication. Almost once per decade, cellular mobile communication is transformed by a significant evolution, with each generation developing a distinctive concept or technology. Interestingly, similar trends have occurred in OWC systems based on visible light and light fidelity (Li-Fi). Unfortunately, OWC is currently relegated to a limited role in any 5G scenario, but the debate whether this is unavoidable has yet to be settled. Whether OWC is adopted post 5G or 6G is not the vital issue; rather, the aim should be that OWC coexists with 5G and 6G communication technologies. In working toward this goal, research and development in OWC will continue to extend its benefits and standardize its systems so that it can be widely deployed in the market. For example, given that a standard already exists for a visible-light beacon identifier and Li-Fi, a service using this standard should be developed to satisfy user demand. Toward this end, we propose herein a method for visible-light beacon identification that involves using a rolling shutter to receive visible-light communications with a smartphone camera. In addition, we introduce a rotary LED transmitter for image-sensor communication.
Deep Learning Detection for superimposed control signal in LEO-MIMO
- R. Okema, D. Goto, T. Yamazato, F. Yamashita, H. Shibayama
- IEEE Global Communications Conference (GLOBECOM), Taipei, Taiwan
- 2020幎12æ
- https://doi.org/10.1109/GLOBECOM42002.2020.9348012
- Multiple-input multiple-output (MIMO) communication systems using multiple low-Earth orbital (LEO) satellites achieve higher capacity than conventional LEO systems. However, in previous research, control signals are allocated to a different frequency band for each satellite signal in order to estimate its Doppler frequency. The increase in the number of satellites reduces unoccupied MIMO signal bandwidth and hence the overall capacity. This study aimed to prevent such capacity reduction by introducing the superimposition of control signals. Such control signals occupy a frequency bandwidth of the equivalent of only one control signal; therefore, they can prevent the reduction of the overall capacity. The main challenge is estimating the satellites' Doppler frequencies from the waveforms of Doppler-affected superimposed control signals. To overcome this challenge, we propose the adoption of a deep learning technique.
Performance Evaluation of Range Estimation for Image Sensor Communication Using Phase-only Correlation
- R. Huang, M. Kinoshita, T. Yamazato, H. Okada, K. Kamakura, S. Arai, T. Yendo, T. Fujii
- IEEE GLOBECOM Workshop on Optical Wireless Communications (OWC), Taipei, Taiwan
- 2020幎12æ
- https://doi.org/10.1109/GCWkshps50303.2020.9367540
- Stereo cameras, serving as the âeyesâ of automotive vehicles, can determine the distance between objects and the vehicles. In this paper, stereo cameras are introduced into image-sensor-based visible light communication (IS-VLC) systems, in which the combination of VLC and stereo ranging shows promising prospects for intelligent transport systems. However, one of the problems of IS-VLC stereo ranging is that the luminance level of LEDs in the captured images would greatly affect disparity estimation, which would result in inaccurate range estimation. This paper gives the performance evaluation of this problem using phase-only correlation algorithm with luminance election. The proposed scheme using stereo cameras exhibited a ranging accuracy of 60±0.15 m in static conditions.
A Comparison of Distance Performances of Modulation Schemes in an ITS Image Sensor Communication
- T. Yamamoto, T. Yamazato, H, Okada, M. Kinoshita, K. Kamakura, S. Arai, T. Yendo, T. Fujii
- International Conference on Emerging Technologies for Communications (ICETC), B4-1, online
- 2020幎12æ
- https://doi.org/10.34385/proc.63.B4-1
- Image sensor communication uses an LED light as a transmitter and an image sensor as a receiver. LED light sources are widely used in traffic lights and car tail lights. In addition, since image sensors are used for driving assistance and drive recorder applications, image sensor communication can be used in parallel with other intelligent transport systems(ITS) applications. This study describes an ITS image sensor communication (ITS-ISC) system, which uses an LED array as a transmitter to imitate traffic lights. There are three schemes of signal transmission using an LED array: luminance modulation, spatial modulation, and both luminance and spatial modulation. However, which of these schemes is the most suitable for ITS-ISC is not yet considered. In this study, we compare the communication performance of these three modulation schemes, present-ing the configuration of an LED array capture simulator and performance comparison results.
Method for considering angle error in the position estimation of a moving target using ultrasonic array
- M.Hattori, A. Tsujii, T. Kasashima, H. Hatano, T. Yamazato
- International Conference on Emerging Technologies for Communications (ICETC), I2-4, Online
- 2020幎12æ
- https://doi.org/10.34385/proc.63.I2-4
- In this study, a method for reducing the angle error in the position estimation of a target is proposed. In this method, the distance between the transmitting array and the target approximates two receiving sensors close to the transmitting array. This enables the attainment of a more accurate distance between the receiving sensor and the target.
Preliminary Circuit Experiment of Photodiode-Type Visible Light Communication by Stochastic Resonance Using Interfering Light as Intentional Noise
- S. Arai, T. Yamazato, H. Hatano, M. Saito, H. Tanaka, Y. Tadokoro
- International Symposium on Nonlinear Theory and its Application (NOLTA), pp.97-100, online
- 2020幎11æ
RSSI-based Distance Estimation Enhanced by Interference Signals
- S. Horiuchi, H. Hatano, K. Sanada, K. Mori, T. Yamazato, A. Shintaro, M. Saito, Y. Tadokoro, H. Tanaka
- International Symposium on Nonlinear Theory and its Application (NOLTA), pp.101-104, online
- 2020幎11æ
A Study on Required FFT Sizes for Demodulation of OFDM Signals by Intentionally Added Noise and 1bit ADC
- M. Saito, T. Ohtaguro, Y. Nakashima, T. Yamazato, S. Arai, H. Hatano, H. Tanaka, Y. Tadokoro
- International Symposium on Nonlinear Theory and its Application (NOLTA), pp.105-108, online
- 2020幎11æ
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- ææ«ç¥ç¢ïŒæšäžé
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- é»åæ
å ±éä¿¡åŠäŒè«æèª, vol.J103-A, no.11, pp.283-286
- 2020幎11æ
- https://doi.org/10.14923/transfunj.2020JAL2005
- æ¬ç ç©¶ã§ã¯ïŒç»åã®é«éã»é«èŒåºŠææ ãå¯èœãªDMD (Digital Micromirror Device)ãããžã§ã¯ã¿ãITS (Intelligent Transport Systems)ã€ã¡ãŒãžã»ã³ãµå¯èŠå
éä¿¡ã®éä¿¡æ©ãšããŠå¿çšããããšãæ€èšããïŒå®æ©ãçšããŠæ§ç¯ããã·ã¹ãã ã«ããïŒå±å€ç§»åç°å¢ã«ãããŠè¡ã£ãéä¿¡æ§èœè©äŸ¡ã«ã€ããŠå ±åããïŒ
Image sensor communications for automotive intelligence
- T. Yamazato
- International Conference on Optoelectronic and Microelectronic Technology and Application 2020, Nanjing, China
- 2020幎10æ
- Almost once per decade, cellular mobile communication is transformed by a significant evolution, with each generation developing a distinctive concept or technology. Interestingly, similar trends have occurred in visible light communication systems and vehicle automation. In this talk, the presenter looks back to the brief history of vehicle automation and related communication technologies. He then introduces visible light communication and its application for automotive intelligence. Some of his research results on VLC for automotive applications will also be provided.
奚å±è¬æŒïŒœæ·±å±€åŠç¿ãçšããè€æ°è¡æã«ãããéç³LEO-MIMOå¶åŸ¡ä¿¡å·ã®ãããã©ãŒã·ããæšå®
- æ¡¶éæ€ïŒäºè€å€§ä»ïŒå±±éæ¬ä¹ïŒå±±äžå²æŽïŒç³žå·å代圊
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, SAT2020-19, pp.47-52, ãªã³ã©ã€ã³
- 2020幎8æ
- äœè»é(LEO)è¡æéä¿¡ã®å€§å®¹éåãç®çãšããŠLEOè¡æã«MIMO(Multi-Input Multi-Output)æè¡ãé©çšããããšãèããïŒåŸæ¥ç ç©¶ã«ãããŠïŒLEO-MIMOä¿¡å·ã®ãããã©ãŒã·ãããæšå®ããçºã«åè¡ææ¯ã«åå¥ã®åšæ³¢æ°åž¯åãå²ãåœãŠèå¥çšã®å¶åŸ¡ä¿¡å·ãéä¿¡ããŠããïŒããã«ããLEO-MIMOã«ãããå¹²æžãé¿ããã倧容éåãå¯èœãšãªãïŒãããMIMOãè¡ãè¡ææ°ãå¢å ãããšå¶åŸ¡ä¿¡å·ã«å²ãåœãŠã垯åå¹
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Sequential Maximum Likelihood Decoding Incorporating Reliability Determination for Image Sensor Communication
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- æ¥æ¬åçæž¬éåŠäŒåä¿¡è¶æ¯éš å
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å ±ã»ãããŒ, ãªã³ã©ã€ã³
- 2020幎7æ
ãã«ãã¢ã³ããåä¿¡æ©ã«ãããéé³ãå©çšãã1bitã¢ããã°-ãã£ãžã¿ã«å€æåšã®ç¹æ§è§£æ
- äžå³¶åº·éïŒå±±éæ¬ä¹ïŒèäºäŒžå€ªéïŒéœè€å°äººïŒçŸœå€éè£ä¹ïŒç°äžå®åïŒç°æå¹žæµ©
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, CS2020-20, pp.25-26, å©å°»,ãªã³ã©ã€ã³(åæéå¬)
- 2020幎7æ
- åè§£èœã1bitã®ã¢ããã°-ãã£ãžã¿ã«å€æåš(ADC)ãçšããåä¿¡æ©ã¯ïŒããªæ³¢éä¿¡ã«ããããã«ãã¢ã³ããåä¿¡æ©ãªã©ïŒçé»åæ§ãé«éåã容æãšããç¹ããé«åè§£èœADCã®å©çšãé£ããç¶æ³ã«ãããä»£æ¿ææ®µãšããŠæ€èšãããŠããïŒäžæ¹ã§1bit~ADCãçšããå ŽåïŒåŸ©èª¿ãããä¿¡å·ã«éç·åœ¢æ§ãçãããïŒçè«çãªæ çµã¿ãããã®éç·åœ¢æ§ã«ã€ããŠæ€èšããç ç©¶ã¯äžååãªç¹ãããïŒæ¬çš¿ã§ã¯ïŒ1bit ADCãçšãããã«ãã¢ã³ããåä¿¡æ©ã®ç¹æ§ã«ã€ããŠïŒéé³ã«ãã£ãŠéç·åœ¢ç³»ã®ç¹æ§ãæ¹åãã確çå
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Visible light beacon
- T. Yamazato
- Signal Processing in Photonic Communications (SPPCom), The 2020 OSA Advanced Photonics Congress, 2020., Online
- 2020幎7æ
- Since the LED (light-emitting diode) is a semiconductor device, high-speed modulation is possible. The communication for transmitting information by blinking (modulating) the LED at such a high speed that the human eye cannot recognize is called visible light communication (VLC) [1]. The visible light beacon is an exciting application of VLC that transmits the short ID. In this article, the trend of the visible light beacon, a part of VLC is described.
Nonlinear Transform for Parallel Transmission for Image-Sensor-based Visible Light Communication
éé³ã掻çšãã1bit ADCåä¿¡æ©ãšç·åœ¢åä¿¡æ©ã®æ¯èŒ
- äžå³¶åº·éïŒå±±éæ¬ä¹ïŒèäºäŒžå€ªéïŒéœè€å°äººïŒçŸœå€éè£ä¹ïŒç°äžå®åïŒç°æå¹žæµ©
- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, B-8-38, p.185, åºå³¶
- 2020幎3æ
- éç·åœ¢æ§ãéé³ã«ãã£ãŠæ¹åãããçŸè±¡ã確çå
±é³ŽãšããïŒãã®çŸè±¡ã«ããïŒåè§£èœã1bitã®ã¢ããã°-ãã£ãžã¿ã«å€æåš(1bit ADC)ãçšããåä¿¡æ©ã«ãããŠãïŒæ¯å¹
ãå€åããä¿¡å·ã埩調å¯èœã«ãªãïŒ1bit ADCãçšããåä¿¡æ©ã¯ïŒåºåž¯åãªå Žåãªã©é«åè§£èœADCã®å©çšãé£ããç¶æ³ã«ãããä»£æ¿ææ®µãšããŠæ€èšãããŠãã.äžæ¹ã§ïŒéé³ã«ãã£ãŠç¹æ§ãæ¹åããçŸè±¡ã«çç®ããŠçè«çãªæ çµã¿ãããã®æ§èœã«ã€ããŠæ€èšããç ç©¶ã¯å°ãªãïŒæ¬çš¿ã§ã¯ïŒèªèº«ã®å
è¡ç ç©¶ã§ææ¡ããïŒéé³ãå ãã£ãå Žåã®1bit ADCã®å
¥åºåç¹æ§ã®è§£æææ³ãçšããŠïŒ1bit ADCåä¿¡æ©ãšç·åœ¢åä¿¡æ©ã®æ§èœå·®ã«ã€ããŠè°è«ããïŒ
Distance and Velocity Measurement of Approaching Target Via 45 kHz Ultrasonic Sensor Array
- Y.H.J Lai, A. Tsujii, T. Kasashima, T. Yamazato, H. Hatano
- IEICE General Conference, A-4-2, p.35, Hiroshima, Japan
- 2020幎3æ
- Ultrasonic sensors are an attractive option for target detection purposes due to their low cost, functionality in all light and weather conditions and easy implementation. Multiple ultrasonic sensors arranged in an array were shown to strengthen ultrasonic waves and increase detection range at static conditions in an indoor environment. In this article, we report a conducted experiment on a moving target in an outdoor environment to analyze its performance and will aim to use the obtained data for localization in future works.
Range Estimation of LED Transmitter Using Phase-Only Correlation for ITS-VLC System via High-speed Stereo Cameras
- R. Huang, M. Kinoshita, T. Yamazato, H. Okada, K. Kamakura, S. Arai, T. Yendo, T. Fujii
- IEICE General Conference, A-9-21, p.100, Hiroshima, Japan
- 2020幎3æ
éé³ãš1bit ADCãçšããOFDMä¿¡å·åŸ©èª¿ã®æèŠFFTãµã€ãºã«é¢ããäžæ€èš
- éœè€å°äººïŒäžå³¶åº·éïŒå±±éæ¬ä¹ïŒèäºäŒžå€ªéïŒçŸœå€éè£ä¹ïŒç°äžå®åïŒç°æå¹žæµ©
- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, A-9-11, p.90, åºå³¶
- 2020幎3æ
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- 髿šé
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- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, A-9-23, p.102, åºå³¶
- 2020幎3æ
RSSIã«åºã¥ãè·é¢æž¬å®æè¡ã®ããã®å¹²æžä¿¡å·ãçšããDitheræ³ã®é©çšã«é¢ããç ç©¶
- å å
æåïŒçŸœå€éè£ä¹ïŒçç°èèŒïŒæ£®éпޥ倫ïŒå±±éæ¬ä¹ïŒèäºäŒžå€ªéïŒéœè€å°äººïŒç°æå¹žæµ©ïŒç°äžå®å
- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, A-14-1, p.118, åºå³¶
- 2020幎3æ
ç³èŸŒã¿ãã¥ãŒã©ã«ãããã¯ãŒã¯ã«ãã2æ³¢LEO-MIMOå¶åŸ¡ä¿¡å·ã®ãããã©ãŒã·ããæšå®
- æ¡¶éæ€ïŒäºè€å€§ä»ïŒå±±éæ¬ä¹ïŒå±±äžå²æŽïŒæŽå±± 倧暹
- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, B-3-7, p.199, åºå³¶
- 2020幎3æ
Visible Light Communications for Automotive Intelligence
- T. Yamazato
- The Optical Networking and Communication Conference & Exhibition (OFC2020), San Diego, USA
- 2020幎3æ
BER Measurement for Transmission Pattern Design of ITS Image Sensor Communication Using DMD Projector
- T. Arisue, T. Yamazato, H, Okada, M. Kinoshita, S. Arai, T. Yendo, K. Kamakura, T. Fujii
- IEEE Consumer Communications and Networking Conference (CCNC), Las Vegas, US
- 2020幎1æ
- https://doi.org/10.1109/CCNC46108.2020.9045147
- This paper presents an image sensor communication (ISC) using a digital micromirror device (DMD) projector as a transmitter. In particular, we focus on ISC for intelligent transport systems (ITSs) because DMD projectors are expected to be used in road traffic, such as vehicle headlights, street lights, and traffic signs. The DMD projector controls light patterns by switching tilt of micromirrors at high speed. Compared to the conventional LED array transmitter, DMD projector can design and alter the shape of the light pattern and data rate of transmission more easily. In the proposed system, the data rate can be easily increased by increasing the number of multiplexes. However, as the number of multiplexes is increased, the number of received pixels on the image sensor is decreased, and thus the performance of symbol detection deteriorates. Therefore, the purpose of this paper is to examine the relation between the num- ber of received pixels per cell and communication performance for transmission pattern design. Hence, we experimentally clarify this relation using our prototype system via a DMD projector and a high-speed camera.
Range Estimation for Traffic Light based on Visible Light Communication using Stereo Cameras
- R. Huang, T. Yamazato, H. Okada, M. Kinoshita, K. Kamakura, S. Arai, T. Yendo, T. Fujii
- Workshop on Optical Wireless Communication for Smart City (OWC2), pp.49-52, Toyota, Japan
- 2019幎12æ
- The recognition of traffic light is important in self-driving cars nowadays. In this paper, we proposed a ranging method for traffic light on the road based on stereo ranging. By introducing the idea of visible light communication, it is simple to extract the traffic light from a complicated background. Experimental result shows that it can work well for the real traffic light.
Nonlinearity Mitigation of Received Luminance Using Inverse Pattern of the LED array in Image Sensor Communication
- T. Yamamoto, T. Yamazato, H, Okada, M. Kinoshita, K. Kamakura, S. Arai, T. Yendo, T. Fujii
- Workshop on Optical Wireless Communication for Smart City (OWC2), pp.53-56, Toyota, Japan
- 2019幎12æ
- In this research, we describe visible light communication (VLC) using an LED array as a transmitter and a high-speed image sensor as a receiver. Such VLC is called an image sensor communication (ISC), and it assigns a symbol to the multilevel brightness of the LED. An issue is a nonlinearity caused by both LED and image sensors. In order to increase the data rate, it is necessary to handle this nonlinearity. In this paper, we first show the nonlinearity by experimental results. We then show that we can ease such nonlinearity by an introduction of an inverse pattern used to track the LED array. We show by the experimental result that the inverse pattern can mitigate the nonlinearity and thus improve the data rate.
Three-Frame Demodulation for Non-Synchronous Square Wave Quadrature Amplitude Modulation
- K. Yamamura, K. Kamakura, M. Kinoshita, T. Yamazato
- Workshop on Optical Wireless Communication for Smart City (OWC2), pp.33-36, Toyota, Japan
- 2019幎12æ
An Experiment of Image Sensor Communication Using Digital Micromirror Device Projector as a Vehicle Headlight
- T. Arisue, T. Yamazato, H, Okada, M. Kinoshita, S. Arai, T. Yendo, K. Kamakura, T. Fujii
- Workshop on Optical Wireless Communication for Smart City (OWC2), pp.1-4, Toyota, Japan
- 2019幎12æ
- This paper presents an image sensor communication (ISC) using a digital micromirror device (DMD) projector as a transmitter. In particular, we focus on ISC for intelligent transport systems (ITSs). DMD projectors are expected to use in road traffic, such as vehicle headlights, street lights, and projectors of traffic signs. Our proposed system projects data patterns on a road or signage for transmission in addition to primary lighting/display function. In this paper, we report a basic experiment of the proposed system using the DMD projector as a vehicle headlight in driving conditions.
Nonlinear Companding Scheme for Parallel Transmission for Image-Sensor-Based Visible Light Communication
- K. Takahashi, K. Kamakura, M. Kinoshita, T. Yamazato
- Workshop on Optical Wireless Communication for Smart City (OWC2), pp.9-12, Toyota, Japan
- 2019幎12æ
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- é»åæ
å ±éä¿¡åŠäŒè«æèª, vol.J102-B, no.12, pp.962-965
- 2019幎12æ
- https://doi.org/10.14923/transcomj.2019JBL4002
- ã€ã¡ãŒãžã»ã³ãµå¯èŠå
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å ±æºã空éçã«åé¢ã§ããããšããïŒå€ªéœå
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å ±æºãšã®åæéä¿¡ãå¯èœã§ããïŒãã®ããïŒã€ã¡ãŒãžã»ã³ãµå¯èŠå
éä¿¡ã¯ITS (Intelligent Transportation System)ã®ãããªå±å€ã»ç§»åç°å¢ã«é©ããŠããïŒæ¬ç ç©¶ã§ã¯ïŒã€ã¡ãŒãžã»ã³ãµå¯èŠå
éä¿¡ãITSãžå¿çšãããããšãæ€èšããïŒéä¿¡ä¿¡å·ã®å€èª¿æ¹åŒãšããŠPWM (Pulse Width Modulation)ãæ¡çšããïŒæ®åœ±ç»åããã®åä¿¡èŒåºŠå€ãšããŠå¹³åå€ãçšãããšãïŒé信波圢ã®ãã¥ãŒãã£æ¯(éä¿¡èŒåºŠå€)ãšåä¿¡èŒåºŠå€ã®éã«éç·åœ¢æ§ãçããïŒåŸæ¥ç ç©¶ã§ã¯ãã¥ãŒãã£æ¯ãå€èª¿å€å€æ°ã«å¿ããŠåäžã«ãªãããã«æ³¢åœ¢ãçæããŠããïŒãã®ããïŒéç·åœ¢æ§ã«ãã£ãŠéä¿¡æ§èœãå£åããããšãèããããïŒããã§ïŒæ¬è«æã§ã¯ïŒéç·åœ¢æ§ã«å¯Ÿå¿ããããïŒäºåã«åŸãçµæããïŒåä¿¡èŒåºŠå€ãåäžã«åŸãããããã«ïŒãã¥ãŒãã£æ¯ãäžåäžãªããªã³ãŒãPWMæ³¢åœ¢ãææ¡ãïŒãããçšããŠç¹æ§æ¹åãå³ãïŒ
Calibration method for an integrated ranging and visible light communication system using stereo cameras
- R. Huang, M. Kinoshita, T. Yamazato, H. Okada, T. Fujii, S. Arai, T. Yendo, K. Kamakura
- International Conference on Materials and Systems for Sustainability (ICMaSS), Nagoya, Japan
- 2019幎11æ
- Camera calibration is an essential part of stereo camera system. By using stereo cameras, it enables simultaneous range estimation and visible light communication (VLC) data transmission, and we can use them for VLC-based intelligent transport system (ITS-VLC).
The ranging accuracy greatly relies on the accurate camera calibration. As the range increases, the estimation error of calibration parameters will make the ranging result worse. In this paper, we introduce stereo cameras into ITS-VLC system, and discuss the calibration method for range estimation. Considering the effect of camera calibration, the proposed scheme using stereo cameras confirms a great ranging accuracy in a static condition, and the estimation errors of calibration parameters are given within 0.05%.
Analysis of Data Collected by the 700 MHz Band Intelligent Transport Systems for Reducing Ambulance Transportation Time
- T. Mitani, T. Yamazato, K. Naito, Y. Mori
- The 8th IEEE International Conference on Conected Vehicles and Expo (ICCVE), Gratz, Austlia
- 2019幎11æ
- https://doi.org/10.1109/ICCVE45908.2019.8965232
- Emergency services around the world face the problem of increasing patient transportation times. The operation of emergency vehicles is fundamentally different from that of general vehicles ; hence, algorithms recommending optimal routes in a conventional way are not always applicable to emergency vehicles. In this study, we analyzed data of inter-vehicle and road-vehicle communication collected at 700 MHz band intelligent transport systems and demonstrated that the overall travel time of emergency vehicles can be reduced by decreasing their travel time at intersections.
è¡è·¯ç¯ãšããŠå©çšå¯èœãª DMD ãããžã§ã¯ã¿ãçšããITS å¯èŠå
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- ææ«ç¥ç¢ïŒå±±éæ¬ä¹ïŒå²¡ç°åïŒæšäžé
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- é»åæ
å ±éä¿¡åŠäŒ åºç€ã»å¢çãœãµã€ãšãã£å€§äŒ, A-9-1, p.64, 倧éª
- 2019幎9æ
- æ¬ç ç©¶ã§ã¯,è¡è·¯ç¯ãšããŠå©çšå¯èœãª DMD (Digital Micromirror Device) ãããžã§ã¯ã¿ãå¯èŠå
éä¿¡ã®éä¿¡æ©ãšããå Žåã® BER (Bit Error Rate) ç¹æ§ã«ã€ããŠæ€èšãã.ããã§,åä¿¡æ©ã«ã¯é«é床ã«ã¡ã©ãçšãã. DMDãããžã§ã¯ã¿ãéä¿¡æ©ã«çšããããšã§,éä¿¡ãã¿ãŒã³ã人ã«ç¥èŠãããªãçšã®é床ã§ã®ææ ãå¯èœã§ãã.ãã®ãã,è¡è·¯ç¯ãš ããŠäœ¿çšããªãã,é«é床ã«ã¡ã©ãéããŠè»äž¡ã«å®å
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å ±ãéä¿¡ããããšãå¯èœã§ãã.æ¬çš¿ã§ã¯,ææ¡ããã·ã¹ãã ã®åºç€æ€èšãšããŠ,鿢ç°å¢ã§ DMD ãããžã§ã¯ã¿ãçšããŠå°é¢ã«éä¿¡ãã¿ãŒã³ãææ ã,éä¿¡å®éšãè¡ã£ãã®ã§å ±åãã.
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- é»åæ
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- 2019幎9æ
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- 2019幎8æ
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å ±éä¿¡åŠäŒè«æèª, Vol. J102B, No.8, pp.614-623
- 2019幎8æ
- https://doi.org/10.14923/transcomj.2018WFP0016
- æ¬è«æã§ã¯ïŒMuti-input/Multi-output (MIMO) ãçšããäœè»éè¡æ (LEO) éä¿¡ã«ãã LEO- MIMO ã·ã¹ãã ã®äŒé容éã®è©äŸ¡æ€èšãè¡ã.LEO ã·ã¹ãã ã¯è¡æã®é«åºŠãéæ¢è¡æ (GEO) ã«æ¯ã¹ãŠäœãã ãšã«ããäœæžè¡°ïŒäœé
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High performance demodulation method with less complexity for image-sensor communication
- Y. Ohira, T. Yendo, S. Arai, and T. Yamazato
- Optics Express, vol.27, no.15, pp.21565-21578
- 2019幎7æ
- https://doi.org/10.1364/OE.27.021565
- This study presents a novel method for signal demodulation for use with visible light communication systems composed of an image sensor as a receiver and light-emitting diode (LED) transmitters. Demodulation is a central challenge in the design of such a system, as the image captured at the image-sensor receiver is deteriorated by distance and noise. We propose a demodulation method that offers performance approaching that of the maximum-likelihood decoding (MLD) method and with significantly less complexity. The proposed method first applies the minimum mean square error (MMSE) method to each LED into reliable LEDs and unreliable LEDs according to the MMSE results and it demodulates the LEDs judged as reliable directly. Then, the MLD method is applied only to the unreliable LEDs to demodulate their signals. The results of numerical simulations and lab experiments are presented to evaluate the performance of this modified demodulation method.
[Invited Talk] Visible Light Communication and Ranging Using High-speed Stereo Cameras
- M. Kinoshita, K. Kamakura, T. Yamazato
- 2019 IEEE SUMMER TOPICALS MEETING SERIES, Photonics in Artificial Intelligence (Photonics-AI), Ft. Lauderdale, FL
- 2019幎7æ
- https://doi.org/10.1109/PHOSST.2019.8794881
- We will introduce an integrated system of visible light communication (VLC) and ranging using high-speed stereo imaging. The system simultaneously decodes a VLC signal while its source tracking portion outputs ranging information. These image sensors are mainly used to provide visual information to the driver.
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- 2019幎6æ
- https://doi.org/10.14923/transcomj.2018JBR0001
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- 2019幎5æ
- è€æ°ã®äœè»é (LEO) è¡æãçšãã MIMO éä¿¡ ( LEO-MIMO æ¹åŒ) 㯠åäžåšæ³¢æ°åž¯åã«ããŒã¿ä¿¡å·ãéç³ããããšã§,éåžžã® LEO æ¹åŒã«æ¯ã¹äŒé容éãåäžã§ãã. ããã,LEO è¡æã§åé¡ãšãªããããã©ãŒã·ãããæšå®ããããã«,åè¡ææ¯ã«å¶åŸ¡ä¿¡å·ãããŒã¿ä¿¡å·ãšã¯å¥ã®åž¯åã«å²åœãŠãã.ãã®ãã, MIMO ã§å©çšãã LEO è¡ææ°ãå¢ãããš, å¶åŸ¡ä¿¡å·çšåž¯åãå
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Maximum Likelihood Decoding Based on Pseudo-Captured Image Templates for Image Sensor Communication
- S. Arai, H. Matsushita, Y. Ohira, T. Yendo, D. He, T. Yamazato
- NOLTA, IEICE, vol.10, no.2, pp.173-189
- 2019幎4æ
- https://doi.org/10.1587/nolta.https://doi.org/10.173
- This paper focuses on an image sensor communication system that uses an LED as the transmitter and a high-speed image sensor (camera) as the receiver. Communication in this scheme depends on the quality of images transmitted from the LED to the sensor. If the image becomes unfocused on the way to the receiver, the LED luminance that make up the signal cannot be detected, so the receiver cannot demodulate the signal data. To overcome this problem, this study proposes a novel demodulation scheme to recover data from a degraded image, based on a maximum likelihood decoding (MLD) algorithm. The proposed method creates template images that imitate all possible blinking patterns produced by the LED transmitter, and then calculates the Euclidean distances between pixels in the captured image and the pseudo images for all possible blinking patterns. Finally, the algorithm chooses the image template with the smallest Euclidian distance from the received signal as the recovered data. Though an exhaustive set of image templates must be prepared for the proposed MLD, the number of templates depends on the number of LEDs on the transmitter. Thus, the computational complexity of this method increases as the number of transmitter LEDs increases. To reduce the computational complexity of the proposed MLD algorithm, the binary differential evolution (BDE) algorithm is used, which is a swarm intelligence technique. Computer simulations are used to evaluate the BDE algorithm's usefulness for reducing computational complexity and improving the BER of the communication system.
An LED Transmitter Detection using Linear SVM and CNN for ITS Image Sensor Communication
- M. Hori, M. Kinoshita, T. Yamazato, H. Okada, T. Fujii, K. Kamakura, T. Yendo, S. Arai
- 3rd International Conference and Exhibition on Visible Light Communications (ICELVC), Seoul, Korea
- 2019幎3æ
- Image sensor communication (ISC) is a type of visible light communications (VLC) that has high affinity with the field of intelligent transport systems (ITSs). In an ISC, accurate detection of the transmitter from a captured image is critical, because the receiver uses pixels that sense VLC signal for data reception. The purpose of this study is to reduce the false-positive and the false-negative probabilities of the transmitter. To achieve this goal, we propose a novel LED transmitter detection method composed of two stages: the candidate extraction stage by a linear support vector machine (SVM) and the classification stage by a convolutional neural network (CNN). Then, we show that the proposed method is robust to vehicle vibration and other noises such as non-transmitter LED compared to the conventional method.
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- 2019幎3æ
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šä¿¡å·ãéç³ãã,端æ«ã§ã¯æ·±å±€åŠç¿ã«ãããããã©ãŒåšæ³¢æ°æšå®ãè¡ãææ³ãææ¡ãã.è¡æã®æ§ãªãã£ãã«ã¢ãã«ãéä¿¡ç¶æ³ãå°äžã«æ¯ã¹ãŠã·ã³ãã«ãªç°å¢ã§ã¯,ããçšåºŠåä¿¡ãã¿ãŒã³ãå¶éããããã,æ©æ¢°åŠç¿ã«ãããã©ã€ã³ãæšå®ã§æ€åºã§ããå¯èœæ§ããã.æ¬çš¿ã§ã¯ããããç°ãªããããã©ãŒåšæ³¢æ°ãçºçãã2è¡æã®éç³ä¿¡å·ã®å信波圢æ
å ±ãã,深局åŠç¿ã«ãããããã©ãŒåšæ³¢æ°æšå®ãè¡ãããšãæ€èšãã.
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- äºè€å€§ä»ïŒå±±äžå²æŽïŒæŽå±±å€§æš¹ïŒæ¡¶éæ€ïŒå±±éæ¬ä¹
- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, B-3-20, p.210, æ±äº¬
- 2019幎3æ
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- é»åæ
å ±éä¿¡åŠäŒè«æèª, vol.J102-B, no.2, pp.90-97
- 2019幎2æ
- https://doi.org/10.14923/transcomj.2018GTP0003
- èŠçè£å©ãç©äœæ€ç¥ãšãã£ãçšéã§æ®åã®é²ãè»èŒã€ã¡ãŒãžã»ã³ãµã¯LEDãšçµã¿åãããããšã§å¯èŠå
éä¿¡ã®åä¿¡æ©ãšããŠäœµçšããããšãå¯èœã§ããïŒã€ã¡ãŒãžã»ã³ãµãçšããå¯èŠå
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å ±ã®ååŸãå¯èœãšãªãã ãã§ãªãïŒã¹ãã¬ãªç»åãæå¹æŽ»çšããããšã§å¯èŠå
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éä¿¡æ§èœã®åäžãç®æãïŒææ¡ææ³ã¯éæ¢ç°å¢åã³èµ°è¡ç°å¢ã«ãããå®éšã«ããïŒåŸæ¥ã®åçŒé«é床ã«ã¡ã©ã«ããåä¿¡ææ³ãšéä¿¡æ§èœã®æ¯èŒè©äŸ¡ãè¡ãïŒãã®æå¹æ§ã瀺ãïŒ
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- 山鿬ä¹ã西éæäººãå è€çŽäººãåæä¿æ
- æ åæ
å ±ã¡ ãã£ã¢åŠäŒèª, vol.73, no.1, pp.96-99
- 2019幎1æ
- ç ç©¶éçºã«ãããŠå
è¡ç ç©¶äŸã®èª¿æ»ã®ããã«åŠè¡æç®ã®èª¿æ»ã¯æ¬ ãããªããããã§ãäžçäžã®åŠäŒãäŒæ¥ã«ãããŠåŠè¡æç®ã«é¢ããããŒã¿ããŒã¹ãæŽåãããŠããããããããã®ç®çãç»é²ãããŠããããŒã¿ãç»é²åœ¢åŒã¯ããŸããŸã§ãããæç®æ€çŽ¢ã®ç®çã«ãã£ãŠäœ¿ãåããå¿
èŠããããæ¬çš¿ã§ã¯ãäž»ãªåŠè¡æç®ããŒã¿ããŒã¹ã玹ä»ããåŠè¡æç®ããŒã¿ã®æ€çŽ¢ãåãå·»ãç°å¢ã¯ Linked Data, LOD ãªã®ã®ããŒã¯ãŒããšæç®ç®¡çããŒã«ã«ã€ããŠè§£èª¬ããã
Enhancing a BPSK receiver by employing a practical parallel network with Stochastic resonance
- Y. Tadokoro, H. Tanaka, Y. Nakashima, T. Yamazato, S. Arai
- NOLTA, IEICE, vol. E10-N, no. 1, pp. 106-114, 2019.
- 2019幎1æ
- https://doi.org/10.1587/nolta.10.106
- Stochastic resonance (SR) is a noise-enhancement phenomenon that enables the detection of sub-threshold signals by adding noise and using nonlinear systems. This paper explores the applicability of SR in a BPSK receiver with sub-threshold signals. Although received signals are amplified as a result of the nonlinear behavior of the receiver, they are somewhat distorted. This results in the lower performance of SR receivers in comparison with linear receivers. Employing a parallel network of SR systems is expected to solve this problem. The present theoretical analysis demonstrates that in a certain noise intensity range, the output of the network can fully describe an input sub-threshold signal, and hence, the performance close to that of the linear receivers can be obtained. The effectiveness of the SR receiver was also demonstrated through a numerical example of the bit error rate (BER). However, achieving good BER performance requires an infinite number of arrayed SR systems, which is not realistic in practical systems. A design framework for an SR network with a finite number of elements and an appropriate noise intensity that can realize BER performance close to that in linear systems is also provided.
LEO-MIMO Satellite Systems for High Capacity Transmission
Performance Evaluation of Precoded Pulse Width Modulation for Image Sensor Communication
- S. Kamegawa, M. Kinoshita, T. Yamazato, H. Okada, T. Fujii, K. Kamakura, T. Yendo, S. Arai
- IEEE GLOBECOM Workshop on Optical Wireless Communications, Abu Dhabi, UAE
- 2018幎12æ
- https://doi.org/10.1109/GLOCOMW.2018.8644347
- Light-emitting diodes (LEDs) can add visible light communication (VLC) by high-speed blinking to their original lighting function. VLC using image sensors as receivers is referred to as image sensor communication (ISC). ISC eliminates noise and interference and enables multiple and simultaneous communication; hence it is suitable for outdoor mobile environments such as intelligent transport systems (ITSs). On the other hand, since the communication rate depends on the frame rate, it is difficult to increase. Therefore, the purpose of this study is to increase the communication rate by multilevel pulse width modulation (PWM). When the modulation level is increased, demodulation becomes difficult due to the bit per pixel (bpp) limitation of the image sensor. First, in order to perform efficient luminance extraction in limited bpp, we compare the maximum luminance extraction and the average luminance extraction. Then, we propose improving the nonlinearity between the transmitter and receiver, which is a problem in average luminance extraction suitable for a mobile environment, by applying precoded PWM. Finally, we evaluate effectiveness of precoded PWM experimentally.
Noise-aided Demodulation with One-bit ADC for Quadrature Amplitude Modulated Signals
- Y. Nakashima, T. Yamazato, S. Arai, H. Tanaka, Y. Tadokoro
- IEEE Global Communications Conference (GLOBECOM), Abu Dhabi, UAE
- 2018幎12æ
- https://doi.org/10.1109/GLOCOM.2018.8648114
- This paper proposes a new demodulation method using a one-bit analog-to-digital converter (ADC). With one bit resolution, a signal having a multilevel signal, such as a quadrature amplitude modulated (QAM) signal, is largely degraded by nonlinearity. To demodulate the signals, a high-resolution ADC is used to receive the signals with high linearity. This study sets out to demodulate the QAM signals using a one-bit ADC, whose resolution is the lowest (one-bit) and possesses outputs of binary (nonlinear) values. We propose to solve the issue by focusing on the statistical characteristics of the output signals of the one-bit ADC combined with noise. The proposed demodulation method is based on maximum a posteriori (MAP) criterion. The theoretical analysis presented illustrates that reliable demodulation is possible even with the one-bit ADC, provided the output probability of the ADC corresponds to each transmitted symbol is known.
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- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, WBS2018-70, pp.237-241, å®®å€å³¶
- 2018幎12æ
- æ¬çš¿ã§ã¯ïŒã€ã¡ãŒãžã»ã³ãµãåä¿¡æ©ã«çšããå¯èŠå
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éä¿¡ã®éä¿¡æ©ãšããŠã¯LEDã¢ã¬ã€ãæ³å®ãããŠããïŒLEDã¢ã¬ã€ã¯ç©ºé䞊åäŒéã«ããé«éåãã§ãããïŒéä¿¡ãã¿ãŒã³ã®å岿°ã圢ç¶ã®èšèšã®èªç±åºŠãäœãïŒãŸã倿Žãå°é£ã§ããïŒããã§ïŒæ¬çš¿ã§ã¯LEDã¢ã¬ã€ã«æ¯ã¹éä¿¡ãã¿ãŒã³ã®å岿°ã圢ç¶ã®èšèšïŒå€æŽã容æã§ãã DMD ãããžã§ã¯ã¿ãéä¿¡æ©ã«çšããéä¿¡ã·ã¹ãã ãææ¡ããïŒDMDãããžã§ã¯ã¿ãçšããéä¿¡æ©ã¯è»äž¡ã®ãããã©ã€ããè¡è·¯ç¯ïŒéè·¯æšèã®æå
åšãšããŠäœ¿çšãå¯èœã§ããïŒéè·¯ãæšèã«éä¿¡ãã¿ãŒã³ãææ ãéä¿¡ãè¡ãããšãæ³å®ããïŒãã®DMDãããžã§ã¯ã¿ãšã€ã¡ãŒãžã»ã³ãµãçšããéä¿¡ã·ã¹ãã ã®ãããã¿ã€ããäœæãïŒå®æ©ãçšããŠéä¿¡ãã¿ãŒã³ã®åºç€æ€èšãè¡ã£ãïŒ
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- 山鿬ä¹ãæŠç°æµ©äž
- 倧åŠICTæšé²åè°äŒ2018幎次倧äŒã[WG2] ç£åŠååã«ããæè²é¢é£ITæè¡ã®æŽ»çšäºäŸå ±å, æå¹ã³ã³ãã³ã·ã§ã³ã»ã³ã¿ãŒïŒåæµ·éæå¹åžïŒ
- 2018幎11æ
- æ¬çš¿ã§ã¯ãå»çåéã§çšããããŠãããå»çãã¹ãŠã§ã€ãã æè²åéã«å¿çšããããšãææ¡ãããå
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- 平岡ç倪éïŒå±±éæ¬ä¹ïŒèäºäŒžå€ªéïŒç°æå¹žæµ©ïŒç°äžå®å
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, RCS2018-179, pp.7-12, é£èŠ
- 2018幎11æ
- 確çå
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±é³Žåä¿¡æ©ïŒã¯åä¿¡æåºŠä»¥äžã®åŸ®åŒ±ãªä¿¡å·ã®æ€åºãå¯èœã«ããããšã瀺ãããŠãã. æ¬çš¿ã§ã¯, éé³ãšããŠå¹²æžæ³¢ãå©çšãã確çå
±é³Žåä¿¡æ©ã®åäœãææ¡ããããã«, PSKå€èª¿ãããä¿¡å·ã®åä¿¡ç¹æ§ã, çè«è§£æãšèšç®æ©ã·ãã¥ã¬ãŒã·ã§ã³ã«ããè©äŸ¡ãã. ãã®çµæ, BERç¹æ§ã¯SIRãšä¿¡å·å¯ŸéŸå€æ¯ã«ããæ±ºå®ãããããšãæããã«ãã. æ¬çš¿ã§åŸãããçµæã¯, å¹²æžæ³¢ãå©çšãã確çå
±é³Žåä¿¡æ©ã®æç¢ºãªèšèšæéã§ãã, æå¹æ§ãé«ããšèãã.
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- æšäžé
ä¹ïŒå±±éæ¬ä¹ïŒå²¡ç°åïŒè€äºä¿åœ°ïŒèäºäŒžå€ªéïŒåéç¥åïŒéåæµ©å£
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, WBS2018-26, pp.47-52, åºå³¶
- 2018幎10æ
- æ¬çš¿ã§ã¯ïŒã€ã¡ãŒãžã»ã³ãµãåä¿¡æ©ã«çšããå¯èŠå
éä¿¡ïŒã€ã¡ãŒãžã»ã³ãµéä¿¡ïŒã®é«åºŠé路亀éã·ã¹ãã (ITS)ãžã®å¿çšã«ã€ããŠæ€èšããïŒã€ã¡ãŒãžã»ã³ãµéä¿¡ã§ã¯æ®åœ±ç»åããéä¿¡æ©ãæ€åºãïŒéä¿¡ä¿¡å·ã埩調ããããšã§åä¿¡ãè¡ãããïŒããããªããïŒITSã€ã¡ãŒãžã»ã³ãµéä¿¡ã§ã¯ïŒè»èŒã®ç§»åã«äŒŽã£ãŠïŒã€ã¡ãŒãžã»ã³ãµäžã§ã®éä¿¡æ©ã®äœçœ®ãç§»åããããšããïŒããã¹ããªéä¿¡ãè¡ãããã«ã¯éä¿¡æ©ã®æ€åºã»è¿œè·¡ãéèŠãšãªãïŒãã®æ§ãªè»èŒã®ç§»åã»æ¯åã«ãã£ãŠçããç»åäžã§ã®éä¿¡æ©ã®ç§»åã¯ã€ã¡ãŒãžã»ã³ãµéä¿¡è·¯ãå€åãããããïŒèæ
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Noise-aided demodulation with one-bit comparator for multilevel pulse-amplitude-modulated signals
- Y. Nakashima, T. Yamazato, S. Arai, H. Tanaka, Y. Tadokoro
- IEEE Wireless Communications Letters, vol.7, no.5, pp.848-851
- 2018幎10æ
- https://doi.org/10.1109/LWC.2018.283168328646
- This paper proposes a demodulation method using a one-bit comparator for signals processed by multilevel pulse amplitude modulation (PAM). The proposed method is simple and provides an alternative to using an analog-to-digital converter to describe multilevel input signals. Because of the noise present in the transmitted multilevel PAM signal, the two-level output of the one-bit comparator shows different statistical behavior for each level of the signal. Thus, it is possible to detect the signal level, or perform symbol decision, based on the maximum likelihood (ML) criterion. The present theoretical analysis reveals that reliable demodulation is possible even with a one-bit comparator if the probability mass function of the two-level outputs of each received symbol plus intentionally added noise is known.
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å ±äº€æãè€æ°æ©åšç¡ç·ãã£ãŒãããã¯å¶åŸ¡ã®å質ã«äžãã圱é¿ã®å®éšçè©äŸ¡
- 山壿ªæ¥ïŒå°æå¥å€ªéïŒå²¡ç°åïŒçå±±æ£æ
- 驿°çç¡ç·éä¿¡æè¡ã«é¢ããæšªæåç ç©¶äŒ(MIKA), no.4-14, äŒæ±
- 2018幎9æ
- æ¬ç ç©¶ã§ã¯Robot Operating System(ROS)ãçšããè€æ°æ©åšç¡ç·ãã£ãŒãããã¯å¶åŸ¡ãæ±ãïŒè€æ°ã®ç§»åãããããšã«ã¡ã©ïŒã³ã³ãããŒã©ã«ããå®éšç³»ãæ§ç¯ã,ROSã®éåææ
å ±äº€æã«ããçããéä¿¡ã®æ··éãå¶åŸ¡å質ã«äžãã圱é¿ã®è©äŸ¡ãè¡ã£ã.ãŸããã®åœ±é¿ãäœæžããããã®æ
å ±äº€æã¿ã€ãã³ã°ã®èª¿æŽãè¡ã£ã.å®éšã«ããè€æ°ã®å¶åŸ¡å¯Ÿè±¡ãç®æšçµè·¯ã«è¿œåŸããããã£ãŒãããã¯å¶åŸ¡ãè¡ã,æ
å ±äº€æã«èŠããæéã»çµè·¯ãžã®è¿œåŸæ§ã®èгç¹ã§éä¿¡ã®æ··éã®åœ±é¿ãæããã«ãã.ãããŠ, æ
å ±äº€æã¿ã€ãã³ã°ã®èª¿æŽã«ãã£ãŠå¶åŸ¡å質ãåäžããŠããããšã瀺ãã.
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- äžå³¶åº·éïŒå±±éæ¬ä¹ïŒèäºäŒžå€ªéïŒç°äžå®åïŒç°æå¹žæµ©
- é»åæ
å ±éä¿¡åŠäŒ éä¿¡ãœãµã€ãšãã£å€§äŒ, B-8-30, p.136, éæ²¢
- 2018幎9æ
- åŸæ¥ã®å·¥åŠã«ãããŠéé³ãæ§èœå£åã®åå ãšããŠæ±ãããŠããäžæ¹ã§ïŒçç©ã¯éé³ãããããšã§æ§èœãåäžã ãçŸè±¡ (確çå
±é³Ž) ãå©çšãïŒå¹ççãªä¿¡å·åŠçãè¡ã£ ãŠãã.ãã®ãããªïŒéé³ãé€å»ããã®ã§ã¯ãªãå©çšããçŸè±¡ã®å·¥åŠå¿çšãçŸåšæ³šç®ãéããŠãã. éä¿¡åéãžã®å¿çšãšããŠïŒãããŸã§ã«ã¯ 1bit ã¢ãã ã°-ãã£ãžã¿ã«å€æåš (1bit ADC) ã«ãã M-ary PAM ä¿¡å·åã³ QAM ä¿¡å·ã®åŸ©èª¿ãæ€èšããŠãã.ãããã® ä¿¡å·ã¯æ¯å¹
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- äºè€å€§ä»ïŒæŽå±±å€§æš¹ïŒå±±äžå²æŽïŒå±±éæ¬ä¹
- é»åæ
å ±éä¿¡åŠäŒ éä¿¡ãœãµã€ãšãã£å€§äŒ, B-3-2, p.196, éæ²¢
- 2018幎9æ
Detectability enhancement using interference signals in wireless communication systems
- S. Hiraoka, Y. Nakashima, T. Yamazato, S. Arai, Y. Tadokoro, H. Tanaka
- International Symposium on Nonlinear Theory and its Application (NOLTA), pp. 705-708, Tarragona, Spain
- 2018幎9æ
- We present a numerical study of an interference-aided detection of a weak (subthreshold) signal in a polarization diversity. We show that the nonlinear signal processing dramatically improves the detectability of the weak signal, supported by an interference signal generated by an appropriate beam control of the antenna arrays. The method takes advantage of subthreshold signal detection by the Stochastic resonance. To postulate a performance of the interference-aided detection, we numerically evaluate the channel capacity provided by the proposed diversity reception on a fading model. Through the numerical analysis, we find that the channel capacity depends on the threshold level of the detector and also the beam pattern determined by the diversity weights in the antenna arrays.
Interference-Aided Detection of Subthreshold Signal Using Beam Control in Polarization Diversity Reception
- S. Hiraoka, Y. Nakashima, T. Yamazato, S. Arai, Y. Tadokoro, H. Tanaka
- IEEE Communications Letters, vol.22, no.9, pp.1926-1929
- 2018幎9æ
- https://doi.org/10.1109/LCOMM.2018.285158328616
- The present letter discusses a detectability enhancement induced by co-channel interference signals in the polarization diversity reception. The challenge is the detection of weak (subthreshold) signals, the level of which is less than the detection limit of radio receivers. To understand the theory underlying the mechanism in the presented diversity scheme, we introduce an analytic model of a dual polarized antenna array in the fading channel. In addition, the channel capacity in a binary data transmission is derived. As a result, we reveal that the interference-aided diversity reception enables us to detect signals even below the detection limit of the receiver. Moreover, the appropriate source code is needed to achieve the channel capacity because the transmission channel is asymmetric in the present reception scheme.
Image Sensor Communications for Automotive
- T. Yamazato
- Progress In Electromagnetics Research Symposium (PIERS), Toyama International Conference Center, Toyama, Japan
- 2018幎8æ
- This article introduces image sensor communications (ISC), a subset of visible light communication (VLC), that use high-speed image sensor and its application to automotive. Li-Fi (light fidelity) and OCC (optical camera communication) or also know as CamCom are also VLC family. Li-Fi is a high-speed wireless system and is currently in the process of being standardized in IEEE 802.11. The OCC uses an ordinary camera, e.g. a smartphone camera, as a receiver while ISC uses a high-speed image sensor as a reception device. The principal component of a camera, an image sensor, is used for both ISC and OCC. The main difference is that ISC focuses on a high-speed image sensor while OCC concentrates on low-cost consumer applications using smartphones and similar contemporary devices. For automotive usage, a high-speed image sensor is the best choice for the VLC receiver because the image sensor has a spatial separation of noise and target source. The VLC family uses LED as the transmitter and LED light sources are everywhere on streets: in signs, traffic lights, street lights, and other stationary objects. So if we can send IDs or exact location data (latitude and longitude) by way of VLC from those LEDs, then they can be used as anchor nodes placed on roads, sidewalks, or landmarks. Those anchor nodes help autonomous cars and connected vehicle for robust navigation with centimeter accuracy. The image sensor is the suitable detection device as it can be used for both positioning and VLC data detection. The author has been working on ISC for automotive applications. In this article, some of the author research, as well as his findings, are introduced.
Overview of image-sensor communication
- T. Yamazato
- Visible Light Communications Workshop, Pacific Rim Conference on Lasers and Electro-Optics (CLEO-PR), Hong Kong Convention and Exhibition Centre, Hong Kong
- 2018幎7æ
- Back in 1998, Prof. Masao Nakagawa invented the concept of visible light communications (VLC) that adopts light emitting diodes (LEDs) as a transmitter. Twenty years of research progress make VLC attractive not only to researchers but also to practitioners. We are about to see blooms of VLC products. Image-sensor communication (ISC) is a form of VLC that uses image-sensor as a reception device. A particular advantage of ISC is an ability to spatially separate light sources. We can use ISC in the outdoor mobile environment. In this presentation, I will review ISC, its application, and future perspective. Some results from the author vis-a-vis ISC and its application to the automobile are also introduced.
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- 2018幎7æ
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Image Sensor Communications for future ITS
- T. Yamazato
- 2018 Advanced Photonics Conference, ã¹ã€ã¹ã»ãã¥ãŒãªããå·¥ç§å€§åŠ
- 2018幎7æ
- This article overviews image sensor communication (ISC), a subset of visible light communication (VLC) system that uses a high-speed image sensor as a reception device. Owing to a massive number of pixels and spatial separation of multiple light souces, ISC can be used in an outdoor mobile environment, suitable for automotive applications. The paper also introduces some results from the authorsâ work on ISC and its application to vehicle-to-everything (V2X) communication.
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- 2018幎5æ
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- 2018幎3æ
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- 2018幎3æ
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- 2018幎3æ
- 人ã®ç®ã«ã¯åãããªãã»ã©LEDïŒlight emitting diodeïŒãé«éã«ç¹æ»
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Performance Enhancement for Image Sensor Communication in an Intelligent Transport System Using a High-speed Stereo Camera
- M. Kinoshita, T. Yamazato, H, Okada, T. Fujii, S. Arai, T. Yendo, K. Kamakura
- International Conference and Exhibition on Visible Light Communications (ICEVLC), Yokohama, Japan
- 2018幎3æ
- In this paper, we propose using a high-speed stereo camera as the image sensor communication (ISC) receiver of an intelligent transport system (ITS). The stereo camera is used for front recognition of the vehicle, making it possible to estimate distances and enabling an integrative system that comprises vehicle front recognition and communication. Furthermore, several stereo images from slightly different views can be obtained at the same time, which provides diversity. Thus the proposed method enhances communication performance owing to the stereo diversity. We also provide experimental results obtained using the high-speed stereo camera and compare them with that of a conventional single high-speed camera. The proposed method improves the bit error rate (BER) performance with respect to the conventional method.
High-speed image processing of VLC signals for automotive applications
- Takaya Yamazato
- International Conference on Optical Wireless Communications, Beijing, China
- 2018幎3æ
Technical Issues on IEEE 802.15.7m Image Sensor Communication Standardization
- T. Nguyen, A. Islam, T. Yamazato, Y. M. Jang
- IEEE Communications Magazine, vol. 56, no. 2, pp. 213-218
- 2018幎2æ
- https://doi.org/10.1109/MCOM.2018.1700134
- This tutorial article presents an outline of image sensor communication (ISC) technologies realized by light sources and cameras. It discusses the revision of the IEEE 802.15.7-2011 standard, namely, the IEEE 802.15.7m Optical Wireless Communications Task Group, which has significantly influenced the development of the ISC technology. It also reviews the ISC technical proposals of the task group and compares them with related works. The essential technical considerations of the ISC specifications are presented, and the future directions of research and development are discussed.
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å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, RCS2017-297, pp.167-174, ãµã³ããŒãããŒã«é«æŸ
- 2018幎1æ
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Simplified Vehicle Vibration Modeling for Image Sensor Communication
- M. Kinoshita, T. Yamazato, H, Okada, T. Fujii, S. Arai, T. Yendo, K. Kamakura
- IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, vol.E101-A, no.1, pp.176-184
- 2018幎1æ
- https://doi.org/10.1587/transfun.E101.A.176
- Image sensor communication (ISC), derived from visible light communication (VLC) is an attractive solution for outdoor mobile environments, particularly for intelligent transport systems (ITS). In ITS-ISC, tracking a transmitter in the image plane is critical issue since vehicle vibrations make it difficult to select the correct pixels for data reception. Our goal in this study is to develop a precise tracking method. To accomplish this, vehicle vibration modeling and its parameters estimation, i.e., representative frequencies and their amplitudes for inherent vehicle vibration, and the variance of the Gaussian random process representing road surface irregularity, are required. In this paper, we measured actual vehicle vibration in a driving situation and determined parameters based on the frequency characteristics. Then, we demonstrate that vehicle vibration that induces transmitter displacement in an image plane can be modeled by only Gaussian random processes that represent road surface irregularity when a high frame rate (e.g., 1000 fps) image sensor is used as an ISC receiver. The simplified vehicle vibration model and its parameters are evaluated by numerical analysis and experimental measurement and obtained result shows that the proposed model can reproduce the characteristics of the transmitter displacement sufficiently.
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å ±éä¿¡åŠäŒèª, vol.101, no.1, pp.59-65
- 2018幎1æ
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V2X communications with an image sensor
- Takaya Yamazato
- Journal of Communications and Information Networks, vol.2, no.4, pp.65-74
- 2017幎12æ
- https://doi.org/10.1007/s41650-017-0044-4
- This paper introduces infrastructure-to-vehicle and vehicle-to-vehicle communications using VLC. A VLC coupled with a high-speed image sensor is introduced (i.e., image sensor communication). The high-speed image sensors provide eyes for autonomous and connected vehicles. VLC imparts data reception capability to image sensors with necessary functions, which can then be provided to autonomous and connected vehicles. In this paper, some of our research on coupling VLC to high-speed image sensors is introduced, including our key findings: the basics of ISC, a vehicle motion model, and range estimation.
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å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, ITS2017-56, pp.251-256, æ²çž
- 2017幎12æ
- æ¬çš¿ã§ã¯é«åºŠé路亀éã·ã¹ãã ïŒITSïŒã®ããã®ã€ã¡ãŒãžã»ã³ãµå¯èŠå
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å ±æºã§ããLEDã¢ã¬ã€éä¿¡æ©ãšæ
å ±ãæããªã人工å
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Overview of visible light communications with emphasis on image sensor communications
- Takaya Yamazato
- Asia-Pacific Conference on Communications (APCC), Perth, WA, Australia
- 2017幎12æ
- https://doi.org/10.23919/APCC.2017.8304093
- The concept of visible light communications (VLC) originates from an Asian professor and adopts light emitting diodes (LEDs) as a transmitter. Three Asian born Nobel Prize winners developed blue LEDs, key devices that produce white lighting. Consequently, VLC and its other forms can be considered as an Asian born wireless technology. This paper overviews VLC with emphasis on image sensor communication (ISC) that uses an image sensor as a reception device for VLC signals. Some results from the author vis-a-vis ISC and its application to automobile are also introduced.
A Stochastic Resonance Receiver for 4-PAM Signals
- Y. Nakashima, T. Yamazato, Y. Tadokoro, S. Arai
- International Symposium on Nonlinear Theory and its Application (NOLTA), pp.291-294, Cancun, Mexico
- 2017幎12æ
- Stochastic Resonance (SR) is considered as a noise enhanced phenomenon, that a response of a nonlinear system is improved by noise. In previous studies, an application of SR for wireless communication has been discussed and an SR receiver, the receiver that demodulate a received signal by SR, was proposed. However, these studies have used a basic modulation signal and have not focused on a signal that transmit information by multi-level amplitude. In this paper, we consider an SR receiver for 4-pulse amplitude modulation (4-PAM) signals. By applying SR, it can demodulate 4-PAM signals by a 1-bit resolution device. We show the system model of the receiver, evaluate its performance by simulation, and show its availability.
N-Stream Superimposed System with m-Point DFT for Image-Sensor-Based Visible Light Communication
- S. Kibe, K. Kamakura, T. Yamazato
- IEEE Global Communications Conference (GLOBECOM), pp. 1-6, Singapore, Singapore
- 2017幎12æ
- https://doi.org/10.1109/GLOCOM.2017.8254784
- This paper proposes an N-stream superimposed system for image-sensor-based visible light communications (ISbased VLC). Based on the principle of m-point discrete Fourier transform (DFT), a phase shift keying (PSK) signal is transmitted over m consecutive time slots mT, where T is a slot duration. In practice, the symbol rate of this paper is R/(m + 1) because a guard slot is inserted every m slots. In the superimposed system, N data streams where the symbol rate of the nth data stream, n = {1, 2, . . . , N}, is 1/(m + 1)n-1 times the symbol rate of the first data stream are combined to form a pulse-width modulated (PWM) wave with a period time T. An IS receiver with a camera operating at a frame rate of R/(m + 1)n-1 fps demodulates data streams whose symbol rate is R/m + 1)n symbol/s or lower. Our experimental results validate that from a superimposed PWM wave of 500-symbol/s and 125-symbol/s data streams, a 2000-fps camera receiver demodulates both of the two data streams and the 500-fps camera receiver does the 125-symbol/s data stream successfully, without shortening individual error-free transmission ranges, compared with non-superimposed systems in which 500-symbol/s and 125-symbol/s data streams are independently transmitted by different light emitting diode (LED) transmitters and received by 2000-fps and 500-fps camera receivers, respectively.
mç¹DFTãçšããNæ
å ±ç³»åéç³ã€ã¡ãŒãžã»ã³ãµåå¯èŠå
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- æšéšä¿®æïŒéåæµ©å£ïŒå±±éæ¬ä¹
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, CS2017-58, pp.21-2, é¿è
- 2017幎11æ
The Uplink Visible Light Communication Beacon System for Universal Traffic Management
- T. Yamazato, N. Kawagita, H. Okada, T. Fujii, T. Yendo, S. Arai, K. Kamakura
- IEEE Access, vol.5, pp.22282-22290
- 2017幎10æ
- https://doi.org/10.1109/ACCESS.2017.2759179
- This paper presents a feasibility study of the uplink visible light communication (VLC) beacon system for the universal traffic management system (UTMS). The UTMS is a traffic management system beneath the National Police Agency of Japan. Currently, 55 000 UTMS infrared beacon systems have been installed, and they provide expressway and ordinary road information to cars. However, the data rate is 1 Mbps, and a faster data rate is necessary to support automotive and smart mobility devices. In this paper, we propose an uplink V2I system for the UTMS. The system is designed to match the current beacon system as closely as possible, so that the system can easily be replaced and still provide sufficient bandwidth for future automotive and smart mobility devices. We adopt a photo diode (PD) as the VLC receiver and a commercially available off-the-shelf LED headlight as a transmitter. Unfortunately, the bandwidth of such an LED is usually small, so we consider applying a bit-loading algorithm to direct-current-biased optical orthogonal frequency division multiplexing. To reduce strong background noise, such as from the sun, we narrow down the field-of-view by applying a lens to the PD, which forms a tiny communication area, smaller than the current infrared beacon system. We then consider multiple PDs with the lens to create a similar communication area as the infrared beacon system. As a result, we achieve 3.1-Mbps throughput.
Modulation and coding for image sensor communication
- K. Kamakura, T. Yamazato
- IEEE Photonics Conference (IPC), pp.235-236, Orlando, FL, USA
- 2017幎10æ
- https://doi.org/10.1109/IPCon.2017.8116086
- Most practical visible light communication (VLC) systems being currently deployed with image sensor receivers use intensity modulation and direct detection scheme for outdoor and indoor applications. A number of modulation and coding techniques that are used for image sensor-based VLC systems are presented.
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- é»åæ
å ±éä¿¡åŠäŒãœãµã€ãšãã£å€§äŒ, A-9-7, p.92, æ±äº¬
- 2017幎9æ
- æ¬çš¿ã§ã¯ LED å
æºãéä¿¡æ©,é«éã€ã¡ãŒãžã»ã³ãµãåä¿¡æ©ã«æ³å®ãã ITS( é«åºŠé路亀éã·ã¹ãã ) ã€ã¡ãŒãžã»ã³ãµéä¿¡ãæ±ã.åŸæ¥ã®ã€ã¡ãŒãžã»ã³ãµéä¿¡ã§ã¯åä¿¡æ©ã«åçŒã«ã¡ã©ãçšããŠããã,æ¬çš¿ã§ã¯é«éäºçŒã«ã¡ã©ãçšããåä¿¡æ©æ§æãææ¡ãã.é«éäºçŒã«ã¡ã©ã§ã¯å·Šå³ã®ã«ã¡ã©ã§èŠãæ¹ãç°ãªã,ãã®éããå©çšããããšã§éä¿¡æ§èœã®æ¹åãå³ã.
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- é»åæ
å ±éä¿¡åŠäŒãœãµã€ãšãã£å€§äŒ, N-2-3, p.196, æ±äº¬éœåžå€§åŠ
- 2017幎9æ
- 確çå
±é³Ž(Stochastic Resonance)çŸè±¡ã¯, é©åãªéé³ãå ããäºã§å¿çãåäžããçŸè±¡ã§ãã. åŸæ¥ã®åä¿¡æ©ã§ã¯æ€åºã§ããªã埮å°ä¿¡å·ãæ€åºããææ³ãšããŠ, 確çå
±é³ŽçŸè±¡ãå¿çšããåä¿¡æ©(確çå
±é³Žåä¿¡æ©)ããã. 確çå
±é³Žåä¿¡æ©ã§ã¯, 確çå
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èŠããã. ãããŸã§ã«ã¯ç¢ºçå
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æã«å ããéé³ãšããŠå©çšããšãææ¡ãã. èšç®æ©ã·ãã¥ã¬ãŒã·ã§ã³ãè¡ãææ¡ææ³ã®æå¹æ§ã確èªãã.
Effect of a Root-Raised-Cosine Filter on a BPSK Stochastic Resonance Receiver
- Y. Nakashima, H. Tanaka, T. Yamazato, Y. Tadokoro, S. Arai
- NOLTA, IEICE, vol.E8-N, no.3, pp.204-214
- 2017幎7æ
- https://doi.org/10.1587/nolta.8.20426846
- Signal filtering is necessary for wireless communication. However it causes the signal amplitude to fluctuate and affects the performance of stochastic resonance (SR) receivers. In this study, we evaluate the bit error rate (BER) performance of filtered binary phase-shift keying (BPSK) on an SR receiver. The results show that filtering improves the BER performance of the SR receiver because the amplitude fluctuation contributes to improving the SR effect. We also evaluate the effect of the roll-off factor, which determines the bandwidth of the filter and the amplitude fluctuation. The results demonstrate the applicability of the SR receiver to bandlimited BPSK signals.
ITS ã€ã¡ãŒãžã»ã³ãµå¯èŠå
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- äºå·æºå²,山鿬ä¹ïŒå²¡ç°åïŒè€äºä¿åœ°ïŒèäºäŒžå€ªéïŒåéç¥åïŒéåæµ©å£
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, RCS2017-69, pp.115-120, ç³å£åå·¥äŒé€š
- 2017幎6æ
- ITS(Intelligent Transport Systems:é«åºŠé路亀éã·ã¹ãã )å¯èŠå
éä¿¡ã«ã€ã¡ãŒãžã»ã³ãµãçšããå Žå,ã€ã¡ãŒãžã»ã³ãµã®ç¹æ§ããé«éåã課é¡ãšãªã.åŸæ¥ã®äŒéæ¹åŒã¯,éä¿¡ä¿¡å·ã®å€èª¿ã«PWM(Pulse Width Modulation:ãã«ã¹å¹
å€èª¿)ãçšããæ¹åŒã§ãã,åä¿¡åŽã§æ¯å¹
å€èª¿ãšããŠæããŠéä¿¡ãè¡ã.ããã«å¯ŸããŠ,é«éäŒéãå®çŸã§ããäŒéæ¹åŒã®åè£ãšããŠ,ä»®æ³æ£åŒŠæ³¢ãçšããæ¹åŒããã.ä»®æ³æ£åŒŠæ³¢æ¹åŒã¯,éä¿¡ä¿¡å·ã®ãã«ã¹ã®æ¯å¹
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,äœçžã®å€èª¿ãšããŠæããŠéä¿¡ãè¡ã.ããã,ãã® 2 ã€ã®äŒéæ¹åŒã®åªäœæ§ãæããã§ãªããã,æ¬ç ç©¶ã§ã¯æ¯èŒå®éšãè¡ã, ITS ã€ã¡ãŒãžã»ã³ãµå¯èŠå
éä¿¡ã®é«éåã®ããã®äŒéæ¹åŒã«ã€ããŠæ€èšãã.
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- äžå³¶åº·é, ç°äžè£ä¹, 山鿬ä¹, ç°æå¹žæµ©, èäºäŒžå€ªé
- é»åæ
å ±éä¿¡åŠäŒ NOLTAãœãµã€ãšãã£å€§äŒ,NLS-3, åå€å±
- 2017幎6æ
- 確çå
±é³Žç³»ãé©çšããåä¿¡æ© ( 確çå
±é³Žåä¿¡æ© ) ã«ãã£ãŠ,埮匱信å·ãéä¿¡ã«å©çšã§ããå¯èœæ§ããã.ãããŸã§ã¯ããŒã¹ãã³ãã§ 2 å€ã®ä¿¡å·ã«å¯Ÿãã確çå
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ã«ãã£ãŠæ
å ±ãäŒéããä¿¡å·ã«å¯ŸããŠã®æ€èšã¯è¡ãããŠããªãã£ã.æ¬çš¿ã§ã¯,4-PAMä¿¡å·ã« 察ãã確çå
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Modeling and Parameter Estimation of Vehicle Vibration Inducing Transmitter Displacement in ITS Image Sensor Communication
- M. Kinoshita, T. Yamazato, H, Okada, T. Fujii, S. Arai, T. Yendo, K. Kamakura
- IEEE International Conference on Communications Workshop on Optical Wireless Communications, pp.144-149, Paris, France
- 2017幎5æ
- https://doi.org/10.1109/ICCW.2017.7962648
- Image sensor communication (ISC), which is derived from visible light communication (VLC), is a novel form of wireless communication that uses an image sensor as a receiver. ISC is an attractive solution for outdoor mobile environments and is particularly wellsuited to intelligent transport systems (ITS). The purpose of this paper is to derive the dominant components of vehicle vibrations and road surface irregularities that induce transmitter displacement in ITS-ICS in paved road scenarios. Such displacements make it difficult for a ISC receiver to select the correct pixels. We measured vehicle vibrations during an actual driving scenario using a sixaxis acceleration sensor installed in a smartphone. Using the results obtained, we performed a frequency analysis of the vehicle vibrations and determined the parameters of vehicle vibrations based on the frequency characteristics. This paper explains that the vehicle vibrations that affect the communication performance can be modeled by solely using Gaussian random processes when a high frame rate (e.g. 1000 fps) image sensor is used as the ISC receiver.
è»èŒæ¯å枬å®ã«åºã¥ã ITS ã€ã¡ãŒãžã»ã³ãµéä¿¡ã«ããã éä¿¡è·¯å€åã®ãã©ã¡ãŒã¿æšå®
- æšäžé
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- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, A-9-14, p.123, åå€å±
- 2017幎3æ
- æ¬çš¿ã§ã¯ LED å
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å ±åæåä¿¡ææ³ã«é¢ããå®éšç³»ã®æ§ç¯
- æ°äºé倧ïŒå±±éæ¬ä¹ïŒå²¡ç°åïŒè€äºä¿åœ°ïŒèäºäŒžå€ªéïŒåéç¥åïŒéåæµ©å£
- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, A-9-15, p.124, åå€å±
- 2017幎3æ
- æ¬ç ç©¶ã§ã¯è»èŒã®ãããã©ã³ããä¿¡å·æ©,ç
§æ,æšç€ºãªã©ãžã®æ®åãå¢ãã€ã€ãã LED ãçšããŠã€ã¡ãŒãžã»ã³ãµéä¿¡ãè¡ãããšã«ãã,次äžä»£ ITS ã®æè¡ãšããŠæåŸ
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å ±éä¿¡åŠäŒ ç·å倧äŒ, A-9-13, p.122, åå€å±
- 2017幎3æ
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- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, A-9-10, p.119, åå€å±
- 2017幎3æ
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å ±éä¿¡åŠäŒ ç·å倧äŒ, B-10-57, p.310, åå€å±
- 2017幎3æ
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- 山鿬ä¹
- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, BI-10-2, pp.SS-81 - SS-82, åå€å±
- 2017幎3æ
- ç¡ç·éä¿¡æ¹åŒã¯ç§»åäœãçžæãšããéä¿¡ææ®µãšããŠã¯ã»ãšãã©å¯äžã®ãã®ã§ããïŒãšãããèªåè»ã«ã€ããŠã¯ïŒæºåž¯é»è©±ïŒç¡ç·LANã®æ®åã«æ©èª¿ãåãããããã«ããŠçºå±ããŠããŠããïŒå³1ã«1980幎以éã®è»è»éã»è·¯è»ééä¿¡ãšæºåž¯é»è©±ïŒGPSã®ç¥å²ã瀺ãïŒããããŠäžŠã¹ãŠã¿ããšïŒèªåè»ã§ã®ç¡ç·å©çšã¯æºåž¯é»è©±ã®10幎é
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- åå€å±å€§åŠéå±å³æžé€šç ç©¶éçºå®€å ±åäŒ, åå€å±å€§åŠ
- 2017幎3æ
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- 2017幎3æ
The Impact on Increase of Penetration of the V2X System Based on ARIB STD-T109 on the Traffic Flow Management at an Intersection
- R. Ohno, T. Yamazato
- RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing (NCSP), pp.81-84, Guam, USA
- 2017幎3æ
- In this paper, we propose a traffic flow management at an intersection using the 760 MHz band V2X (Vehicle-to-X) system based on ARIB STD-T109. Using the V2X system, a road side unit (RSU) can obtain the vehicular information such as the vehicle position, speed and route. Based on the vehicular information, a ``support phase'' can be inserted to a cycle of traffic signal that controls traffic flow at an intersection. We define the âsupport phaseâ as the phase of changing the stop/go sign of the traffic signal on an intersection as necessary. In this way, it is expected to shorten the travel time of the vehicles. We evaluate the algorithm by a traffic simulator in terms of mean speed of all vehicles while passing through the intersection with considering V2X penetration rate.
Vehicle to Infrastructure Visible Light Communication using DCO-OFDM
- N. Kawagita, T. Yamazato, H. Okada, T. Fujii, S. Arai, T. Yendo, K.Kamakura
- RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing (NCSP), pp.129-132, Guam
- 2017幎3æ
- In this paper, we focus on the vehicle to infrastructure visible light communication (V2I-VLC) for intelligent transportation systems (ITS). We propose a V2I-VLC system using LED headlights as transmitters and photodiodes (PDs) with an optical lens as receivers. We adopt DC biased optical orthogonal frequency division multiplexing (DCO-OFDM) as a modulation scheme in order to realize high speed communication. As a results of the data transmission experiments in the driving situation, we achieve data rate of 2.7 Mbps using 32QAM.
A Modulation Method to Detect Phase Shift from Asynchronous Camera Image for Visible Light Communication
- W. Kihara, T. Yendo, S. Arai, T. Yamazato, H. Okada, K. Kamakura
- RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing (NCSP), pp.133-136, Guan, USA
- 2017幎3æ
Range Estimation Scheme for Integrated I2V-VLC using a High-Speed Image Sensor
- T. Yamazato
- Presentation at Professor Jean Armstrong's Laboratory, Monash University, Monash University, Australia.
- 2017幎3æ
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- 2017幎2æ
Global Communications Newsletter -- Asia/Pacific Region Interview with Takaya Yamazato, Director of the AP Region --
- Stefano Bregni, Takaya Yamazato, Vasile Bota, Liangping Ma
- IEEE Communications Magazine, Vol. 55, No. 2, pp.13-16
- 2017幎2æ
- https://doi.org/10.1109/MCOM.2017.7841463
- This is the fourth article in the series of eight, started in November 2016 and published monthly in the IEEE ComSoc Global Communi- cations Newsletter, which covers all areas of IEEE ComSoc Member and Global Activities. In this series of articles, I am introducing the six MGA Directors (Sister and Related Societies; Membership Services; AP, NA, LA, EMEA Regions) and the two Chairs of the Women in Communications Engineering (WICE) and Young Professionals (YP) Standing Committees. In each article, one by one they present their sector activities and plans. In this issue, I interview Takaya Yamazato, Director of the Asia/ Paci c Region (AP). Takaya is a professor at the Institute of Liberal Arts and Sciences, Nagoya University, Japan. He received the Ph.D. degree from Keio University, Yokohama, Japan, in 1993. From 1993 to 1998 he was an assistant professor in the Department of Information Electronics, Nagoya University, Japan. From 1997 to 1998 he was a visiting researcher in the Research Group for RF Communications, Department of Electrical Engineering and Information Technology, University of Kaiserslautern, Germany. In 2006 he received the IEEE Communication Society Best Tutorial Paper Award. He served as symposium co-chair of ICC 2009 and ICC 2011. From 2008 to 2010 he was the chair of the IEEE ComSoc Satellite and Space Communications Technical Committee and the editor-in-chief of the Japanese Section of IEICE Transactions on Communications. His research interests include visible light communication, intelligent transport systems, stochastic resonance, and open educational resources. It is a pleasure for me to interview Takaya for this issue and o er him this opportunity to outline his current activities and plans as Director of the AP Region.
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- 2016幎12æ
Position estimation of LED matrix in image sensor communication
- T. Asai, T. Yendo, S. Arai, T. Yamazato, H. Okada, T. Fujii, K. Kamakura
- Asia-Pacific Signal and Information Processing Association Annual Summit and Conference (APSIPA), pp.1 - 5
- 2016幎12æ
- https://doi.org/10.1109/APSIPA.2016.7820809
- We focus on the road-to-vehicle visible light communication (VLC) that system is composed of a LED matrix as a transmitter and a high-speed camera as a receiver. In this VLC system, intensity of each LED cannot be determined from received image directly in case that the receiver is distant from the transmitter. In previous research, a method to estimate intensity of the LED from received image is proposed. In this method, intensity of LED is estimated by using Moore-Penrose pseudo-inverse matrix of coefficient matrix, which expresses relation between intensity of LEDs and pixel values. However, the coefficient matrix changes every moment because it is determined by positional relation between the receiver and the LED traffic light in VLC system. In this paper, we propose a method to estimate position of the LED matrix using simulated images. We measure sensitivity distribution of image sensor to generate simulated images. We evaluated degree of similarity between simulated images and real images.
Vehicle Vibration Model that Induces Channel Fluctuation in ITS Image Sensor Communication
- M. Kinoshita, T. Yamazato, H, Okada, T. Fujii, S. Arai, T. Yendo, K. Kamakura
- Cambodia-Japan Joint Workshop on Ambient Intelligence and Sensor Networks, ã·ã¥ã ãªã¢ãã
- 2016幎12æ
- Image sensor communication (ISC) enables multiple and simultaneous signal reception because of itsãability spatially separate multiple sources. Therefore, ISC is an attractive solution for an outdoor mobile environment, in particular, in the field of intelligent transport systems (ITS). In ISC, since a transmitter position moves in an image plane according to vehicle movement, detection and tracking of transmitter is critical issue for robust data reception. Such movement referred to as optical ow causes ISC channel to fluctuate and must be considered to receive the signal accurately. In this paper, we conducted vehicle vibration measurement in well paved road and analyzed the frequency characteristic. According to the measured result, we proposed a vehicle vibration model and determined its parameters.
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- 2016幎11æ
Effect of a Root-Raised-Cosine Filtered BPSK Signal on a Stochastic Resonance Receiver
- Y. Nakashima, H. Tanaka, T. Yamazato, Y. Tadokoro and S. Arai
- International Symposium on Nonlinear Theory and its Application (NOLTA), pp.407-410, Yugawara,Japan
- 2016幎11æ
- Signal filtering is necessary for wireless communication however it fluctuates the signal amplitude and affects the performance of a stochastic resonance (SR) receiver. In this paper, we evaluate the bit error rate (BER) performance of filtered binary phase shift keying (BPSK) on an SR receiver. The result shows that filtering improves the BER performance of the SR receiver because the amplitude fluctuation contributes to improving the SR effect, indicating the applicability of the SR receiver to bandlimited BPSK signals.
Channel Measurement of Infrastructure-to-Vehicle Image Sensor Communication
- M. Kinoshita, T. Yamazato, H, Okada, T. Fujii, S. Arai, T. Yendo, K. Kamakura
- 23rd World Congress on Intelligent Transport Systems , Melbourne, Australia
- 2016幎10æ
- In this paper, we focus on the visible light communication (VLC) for ITS application using LED light source as a transmitter and high-speed image sensor as a receiver (image sensor communication: ISC). In ISC, the data reception is performed by extracting luminance corresponding to the transmitter from captured images. However, since either transmitter, receiver, or both moves with vehicles, the transmitter position is moved between frames and it confuses receiver to select the correct pixels. Hence, we treat such movement referred to as optical flow as channel fluctuation. In our previous work, we proposed a model that expressed motion of transmitter in captured images by using a single pinhole camera. In this paper, we derive channel fluctuation characteristic by numerical analysis based on the proposed model and evaluate its validity by comparing with channel fluctuation characteristic obtained by actual measurement.
BPSK ãš QPSK ã«å¯Ÿãã確çå
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- 2016幎9æ
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Visible Light Communication Systems Using Blue Color Difference Modulation for Digital Signage
- S. Sato, H. Okada, K. Kobayashi, T. Yamazato, M. Katayama
- IEEE International Symposium on Personal, Indoor and Mobile Radio Communication (PIMRC), pp.1242-1247, Valencia, Spain
- 2016幎9æ
- https://doi.org/10.1109/PIMRC.2016.7794761
- Digital signage, which is advertising media using a liquid crystal display (LCD), is increasing in popularity. One possible application is wireless communications between digital signage and viewers. We focus on image-sensor-based visible light communication (VLC). Image-sensor-based VLC requires only an image sensor (IS), which is common equipment in smart phones. In the proposed method, an nformation signal is displayed on LCD. However, embedding the information signal into an advertisement may decrease the quality. We propose blue color difference modulation to make such signals imperceptible. We implemented a VLC system between digital signage and IS to demonstrate, the effectiveness of the proposed modulation in a real environment.
Spatial Modulation in Layered Space-Time Coding for Image-Sensor-Based Visible Light Communication
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- 2016幎7æ
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Performance comparison of stochastic resonance receiver with Schmitt trigger, comparator, and three-level device for subthreshold signal reception
- H. Tanaka, T. Yamazato, Y. Tadokoro, S. Arai
- Nonlinear Theory and Its Applications, IEICE, vol.7, no.3, pp.407-418
- 2016幎7æ
- https://doi.org/10.1587/nolta.7.407
- This paper discusses the stochastic resonance (SR) effect in a binary communication system for subthreshold signal reception. We focus on the problem of no communication when received signal strength is below receiver sensitivity. Subthreshold signal reception requires a device that exhibits SR, such as a Schmitt trigger or a comparator. Previously, we proposed an alternative three-level device and demonstrated its high performance for subthreshold signal reception in an SR receiver. In the present study, we show that our proposed three-level device outperforms the three devices and discuss reasons for this superior performance. Contributions of our present paper are twofold: first, we analytically derive bit error rate (BER) performances of SR receivers installed with a Schmitt trigger and a comparator; second, we compare performances of the Schmitt trigger, comparator, and three-level device.
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A New Automotive VLC System Using Optical Communication Image Sensor
- Y. Goto, I. Takai, T. Yamazato, H. Okada, T. Fujii, S. Kawahito, S. Arai, T. Yendo, K. Kamakura
- IEEE Photonics Journal, vol.8, no.3
- 2016幎6æ
- https://doi.org/10.1109/JPHOT.2016.2555582
- As a new technology for next-generation vehicle-to-everything (V2X) communication, visible-light communication (VLC) using light-emitting diode (LED) transmitters and camera receivers has been energetically studied. Toward the future in which vehicles are connected anytime and anywhere by optical signals, the cutting-edge camera receiver employing a special CMOS image sensor, i.e., the optical communication image sensor (OCI), has been prototyped, and an optical V2V communication system applying this OCI-based camera receiver has already demonstrated 10-Mb/s optical signal transmission between real vehicles during outside driving. In this paper, to reach a transmission performance of 54 Mb/s, which is standardized as the maximum data rate in IEEE 802.11p for V2X communication, a more advanced OCI-based automotive VLC system is described. By introducing optical orthogonal frequency-division multiplexing (opticalOFDM), the new system achieves a more than fivefold higher data rate. Additionally, the frequency response characteristics and circuit noise of the OCI are closely analyzed and taken into account in the signal design. Furthermore, the forward-current limitation of an actual LED is also considered for long operational reliability, i.e., the LED is not operated in overdrive. Bit-error-rate experiments verify a system performance of 45 Mb/s without bit errors and 55 Mb/s with BER < 10-5.
Range estimation scheme for integrated I2V-VLC using a high-speed image sensor
- T. Yamazato, A. Ohmura, H. Okada, T. Fujii, T. Yendo; S. Arai, K. Kamakura
- IEEE International Conference on Communications Workshops (ICC), pp.326-330, Kuala Lumpur, Malaysia
- 2016幎5æ
- https://doi.org/10.1109/ICCW.2016.7503808
- High-speed image sensors, designed for machine vision and control, provide the eyes for autonomous and connected vehicle. A noteworthy feature of high-speed image sensors is their ability to be used as a reception device for visible light communication (VLC) signals. Due to the massive number of pixels available and the ability to spatially separate sources, a signal-receiving pixel in the image sensor plane represents the actual position of the transmitter. The VLC signal can be represented not only by a VLC time domain signal but also by the position of the transmitter. In this paper, we propose a robust range estimation scheme that integrates with a VLC function for infrastructure-to-vehicle visible light communication (I2V-VLC). The scheme is composed of an LED array transmitter and a high-speed image sensor receiver. It measures a range by taking phase-only correlation (POC) and avoids vehicle vibration from road irregularity. Field trials confirm an accuracy range of 0.3 m, even on rough road conditions, with the measurement time of 2 ms, which is much faster than that of light detection and ranging (LIDAR).
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Transmit diversity with single RF front-end using CIOD
- T. Yamaoka, T. Hara, A. Okazaki, T. Yamazato
- IEICE Communications Express, vol.5, no.2, pp.44-48
- 2016幎2æ
- https://doi.org/10.1587/comex.2015XBL0170
- Complex interleaved orthogonal design (CIOD) can offers diversity gain to the part of the source in spatial modulation which has single radio frequency (RF) front-end at the transmitter despite multiple-inputmultiple-output, but emits the undesired component out-of-band. For the reducing out-of-band emission, we give up indicating the information source by the antenna switching and increase both the interleaver size and the antenna switching interval. The increase reduces the discontinuities in the waveform and out-of-band emission. We propose such a scheme as transmit diversity with single RF front-end using CIOD. The diversity gain of the proposed scheme is equivalent to the case for CIOD. Moreover, we evaluate the increase of out-of-band emission and confirm that of the proposed scheme compared to the ideal case is only 3dB.
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å ±éä¿¡åŠäŒè«æèª, vol.J99-B, no.2, pp.97-104
- 2016幎2æ
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Novel Demodulation Scheme Based on Blurred Images for Image-Sensor-Based Visible Light Communication
- Y. Ohira, S. Arai, T. Yendo, T. Yamazato, H. Okada, T. Fujii and K. Kamakura
- IEEE GLOBECOM Workshop on Optical Wireless Communication, San Diego, CA, USA
- 2015幎12æ
- https://doi.org/10.1109/GLOCOMW.2015.7414144
- This paper proposes a novel data detection scheme based on the occurrence of blurred output images in image-sensor-based visible light communication systems. This system's receiver suffers from an inability to detect correct LED luminance values and demodulation of data because the captured image blurs owing to defocusing. The proposed method assumes that the light emitted by all LEDs that is diffused by the blur can be approximated by applying a Gaussian filter and expressesall LED luminance values as convolution equations based on this diffusion of the LED light. We estimate each LED light's condition by simultaneously solving these convolution equations and recover data according to the estimated result. To confirm the accuracy of the proposed method, we conduct computer simulations and an implementation experiment to evaluate the bit error rate performance of the proposed method.
A note on subthreshold signal reception using stochastic resonance receiver - Comparison of dynamical and non-dynamical devices -
- H. Tanaka, T. Yamazato, Y. Tadokoro, S. Arai
- International Symposium on Nonlinear Theory and its Application (NOLTA), Hong Kong, China
- 2015幎12æ
- Stochastic resonance (SR) is an interesting phenomenon in that noise enhances system responses. Despite an attractive phenomenon of SR that noise enhances a weak signal below a receiver sensitivity, few researchers have addressed the SR effect in communication systems. Previously, we proposed an analysis method for the SR receiver with a device exhibiting SR and evaluated its bit error rate (BER) performance. However, the device was limited to a non-dynamical device, and there is room for improving the performance of the SR receiver by changing the device. In this paper, we use two typical devices exhibiting SR, i.e., a comparator as a non-dynamical device and a Schmitt trigger as a dynamical device. We evaluate the BER performances of these devices with analysis methods and numerical simulations. A performance comparison of these devices is also shown.
Performance Analysis of Wireless Mesh Networks Using Forward/Reverse-Link Multi-User MIMO
- C. Fuwa, H. Okada, K. Kobayashi, M. Katayama
- International Symposium on EcoTopia Science (ISETS), no.P-6-2, Nagoya, Japan
- 2015幎11æ
- IEEE 802.11ac, which is the latest standard of IEEE 802.11, supports forward-link (downlink) MU (Multi-User)-MIMO (Multiple-Input Multiple-Output), and it can improve the transmission efficiency. IEEE 802.11ax, which is under standardization, is considered to apply reverse-link (uplink) MU-MIMO, and a further improvement of the efficiency is expected. In this paper, we propose to introduce reverse-link MU-MIMO in addition to forward-link MU-MIMO for wireless mesh networks, and evaluate the performance in terms of area transmission efficiency, which indicates a number of packets in a unit area. Then, we clarify that the proposed system achieves the higher area transmission efficiency than forward-link MU-MIMO.
I2V-VLC Vehicle Motion Modeling Using Actual Vehicle Vibration
- M. Kinoshita, T. Yamazato, H, Okada, T. Fujii, S. Arai, T. Yendo, K. Kamakura
- International Workshop on Vision, Communications and Circuits (IWVCC) , Yokohama, Japan
- 2015幎11æ
- Image-sensor-based visible light communications (IS-VLC), or also known as image sensor communication (ISC) and camera communications (CamCom), is one of emerging segment in the field of visible light communications (VLC). As the name indicates, IS-VLC uses light-emitting diodes (LEDs) or an LED array for the transmitter by modulating LEDâs intensity at high speeds that are undetectable to the human eye. For the reception device, IS-VLC adopts image-sensor. In our previous work, we have proposed vehicle motion model that expresses the motion of VLC transmitter in image plane by single pinhole camera model. In this paper, we performed a simulation based on vehicle motion model for infrastructure-to-vehicle VLC (I2V-VLC) with actual vehicle vibration measured by 6- axis acceleration sensor of smartphone and evaluated its channel characterized by optical flow.
Performance Evaluation of Stochastic Resonance Receiver for Dynamical and Non-Dynamical Devices in QPSK Modulation
- H. Tanaka, T. Yamazato, S. Arai
- International Workshop on Vision, Communications and Circuits (IWVCC) , Yokohama, Japan
- 2015幎11æ
- This paper evaluates the performance of the stochastic resonance (SR) receiver for subthreshold signal reception. We focus on the problem of no communication when received signal strength is below receiver sensitivity. Previously, we proposed a SR receiver installed with a typical device exhibiting SR in BPSK modulation and presented the performance improvement for subthreshold signals. However, the performances of other nonlinear devices exhibiting SR are not clear, and we require the performance evaluation for various nonlinear devices. And also, the performance evaluation in multi-level modulation is not presented. In this paper, we evaluate bit error rate (BER) performances of SR receivers installed with a three-level device, a Schmitt trigger and a comparator in QPSK modulation.
[Exhibition] An Optical Camera Communication System Using Digital Signage
- S. Sato, H. Okada, K. Kobayashi, T. Yamazato, M. Katayama
- International Conference and Exhibition on Visible Light Communications (ICEVLC), Yokohama, Japan
- 2015幎10æ
Tracking of LED headlights considering NLOS for an image sensor based V2I-VLC
- Y. Kawai, T. Yamazato, H. Okada, T. Fujii, T. Yendo, S. Arai, K. Kamakura
- International Conference and Exhibition on Visible Light Communications (ICEVLC), Yokohama, Japan
- 2015幎10æ
- This paper focuses on image sensor based vehicle-to-infrastructure visible light communication (V2IVLC) for Intelligent Transport Systems (ITSs). Because the image sensor can spatially separate multiple or noise sources, its receiver can simultaneously demodulate multiple sources. Thus, we consider multiple source reception from multiple vehicles. In image sensor based VLC, the transmitted data are received by extracting the luminance corresponding to the VLC transmitter from the captured image. Transmitter detection and tracking are an important requirement of these systems but are degraded by occlusion, which causes non-line of sight (NLOS). We focus on tracking of transmitters that may be occluded by moving vehicles in V2I-VLC. Our proposed method detects multiple LED headlights by combining a background difference method with an LED detection method based on time and space gradients. We also propose a tracking method based on optical flow-based tracking, which handles occlusion by linear or second-curve interpolation. The proposed methods were evaluated by a high-speed camera placed by the roadside. The false-positive and falsenegative tracking rates were 6.25% and 3.32%, respectively, at κ = 60 (where κ defines the permissible error in the optical flow).
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å ±ã¡ãã£ã¢åŠäŒæè¡å ±å, BCT2015-74, pp.21-24, 山圢
- 2015幎10æ
- æ¬çš¿ã§ã¯ïŒæ¶²æ¶ãã£ã¹ãã¬ã€çãçšããé»ååºååªäœã§ããããžã¿ã«ãµã€ããŒãžã«ããå¯èŠå
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Development of add-on stochastic resonance device for the detection of subthreshold RF signals
- K. Chiga, H. Tanaka, T. Yamazato, Y. Tadokoro, S. Arai
- Nonlinear Theory and Its Applications, IEICE, vol. 6, no. 4, pp. 520-533
- 2015幎10æ
- https://doi.org/10.1587/nolta.6.520
- Stochastic resonance (SR) is a nonlinear phenomenon that, under certain conditions, can enhance system response by adding noise to the signals of some nonlinear system. A particular advantage of SR over conventional linear systems is that it is able to detect subthreshold signals that linear systems hardly sense. Unfortunately, most research of SR in wireless communication systems has focused on fundamental analysis, leaving work to be done in experimental SR research despite the attractiveness of its application. Few attempts have so far addressed the development of SR receivers to show the feasibility of subthreshold signal detection. Those receivers that have been developed are simple ones specially made to confirm the usefulness of SR without needing to support state-of-the-art wireless radio technology. The purpose of this study is to examine the feasibility of using an SR receiver to receive subthreshold radio frequency (RF) signals. A new add-on SR device is developed and confirmation that the SR phenomenon exists within RF is obtained when using software defined radio (SDR) as the post-processing receiver. Furthermore, bit error rate (BER) performance is mainly governed by the add-on SR device's output signal quality.
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å ±é¢ä¿åŠäŒæ±æµ·æ¯éšé£å倧äŒ, K5-4, åå€å±å·¥æ¥å€§åŠ
- 2015幎9æ
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Vehicle Motion and Pixel Illumination Modeling for Image Sensor Based Visible Light Communication
- T. Yamazato, M. Kinoshita, S. Arai, E. Souke, T. Yendo, T. Fujii, K. Kamakura, H. Okada
- IEEE Journal on Selected Areas in Communications, vol.33, no.9, pp.1793-1805
- 2015幎9æ
- https://doi.org/10.1109/JSAC.2015.2432511
- Channel modeling is critical for the design and performance evaluation of visible light communication (VLC). Although a considerable amount of research has focused on indoor VLC systems using singleelement photodiodes, there remains a need for channel modeling of VLC systems for outdoor mobile environments. In this paper, we describe and provide results for modeling image sensor based VLC for automotive applications. In particular, we examine the channel model for mobile movements in the image plane as well as channel decay according to the distance between the transmitter and the receiver. Optical flow measurements were conducted for three VLC situations for automotive use: infrastructure to vehicle VLC (I2V-VLC); vehicle to infrastructure VLC (V2I- VLC); and vehicle to vehicle VLC (V2V-VLC). We describe vehicle motion by optical flow with subpixel accuracy using phase-only correlation (POC) analysis and show that a single-pinhole camera model successfully describes these three VLC cases. In addition, the luminance of the central pixel from the projected LED area versus the distance between the LED and the camera was measured. Our key findings are twofold. First, a single-pinhole camera model can be applied to vehicle motion modeling of a I2V-VLC, V2I-VLC, and V2V-VLC. Second, the DC gain at a pixel remains constant as long as the projected image of the transmitter LED occupies several pixels. In other words, if we choose a pixel with highest luminance among the projected image of transmitter LED, the value remains constant, and the signal-to-noise ratio does not change according to the distance.
Layered Transmission of Space-Time Coded Signals for Image-Sensor-Based Visible Light Communications
- Katsunori Ebihara, Koji Kamakura, Takaya Yamazato
- Journal of Lightwave Technology, Vol.33, No.20, pp.4193 - 4206
- 2015幎8æ
- https://doi.org/10.1109/JLT.2015.2470091
- This paper demonstrates the feasibility of layered space-time coding (STC) in an outdoor image-sensor-based (ISbased) visible light communication (VLC) system. We examined that for low-resolution IS-based VLC channel where intensity-modulated signals from two different light emitting diodes (LEDs) are detected by one pixel of an IS, STC allows us to decouple them; thus, succeeding to receive them with no errors. Consequently, STC offers extended transmission distance to pixel-resolution-limited IS-based VLC links. In the layered STC presented in this paper, additional bit streams are laid on the 2n à 2n LED array for increasing the transmission rate per symbol duration for the case where the pixel resolution is improved. A prototype of a threelayered STC is built with an 8 à 8 LED array, where each of the LEDs is modulated at 1 kb/s and a high-speed camera with IS operating at 1000 fps. Our experimental results validate that the two additional bit streams (layer-2 and -3), aligned in the layer-1 STC matrix pair, are extracted with no errors when the receiver comes within 155 and 55 m, respectively, from the LED array, without decreasing 210 m of the transmission distance of layer-1 bit stream.
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- å¹³æ27幎床ãã©ããã¯ã¹æè¡ãã©ãŒã©ã ã第äžå次äžä»£å
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- 2015幎7æ
[Invited Talk] Image Sensor Based Visible Light Communication for V2X
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- 倧平ç¥çïŒèäºäŒžå€ªéïŒåéç¥åïŒå±±éæ¬ä¹ïŒå²¡ç°åïŒè€äºä¿åœ°ïŒéåæµ©å£
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å ±éä¿¡åŠäŒè«æèª, vol.J98-B, no.7, pp.696-706
- 2015幎7æ
- æ¬è«æã§ã¯LEDä¿¡å·æ©(éä¿¡æ©)ãšè»èŒé«é床ã«ã¡ã©(åä¿¡æ©)ã䜿çšããè·¯è»éå¯èŠå
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LED acquisition methods for image-sensor-based visible light communication
- Shintaro Arai, Takaya Yamazato, Hiraku Okada, Toshiaki Fujii, Tomohiro Yendo
- Opto-Electronics and Communications Conference (OECC), pp.1-3
- 2015幎6æ
- https://doi.org/10.1109/OECC.2015.7340210
- Abstract: This invited paper focuses on a high-speed image sensor as a visible light communication (VLC) reception device to develop the intelligent transport systems (ITS) application using VLC technique. We refer to the VLC using a high-speed image sensor as image-sensor-based VLC. A major advantage of the image sensor is the ability to spatially separate multiple sources. Based on this ability, we proposed several methods for the image-sensor-based VLC in our previous researches. Especially, we focused on unique characteristics of the image sensor and proposed the hierarchical coding and the overlay coding to improve the data reception performance. However, to perform the image-sensor-based VLC in an actual environment, the receiver has to acquire the VLC transmitter from captured images before recovering data. Namely, the VLC transmitter acquisition and tracking are critical problem. the image-sensor-based VLC technique. This invited paper introduces two proposed methods to acquire the VLC transmitter from images captured by the image sensor.
Layered space-time coding using LED array for image-sensor-based visible light communications
- Katsunori Ebihara, Koji Kamakura, Takaya Yamazato
- IEEE International Conference on Communications (ICC), pp.5048-5053, London, UK
- 2015幎6æ
- https://doi.org/10.1109/ICC.2015.7249124
- This paper demonstrates the feasibility of layered space-time coding (STC) in an outdoor image-sensor-based (IS-based) visible light communication (VLC) system. We examined that for low-resolution IS-based VLC channel where intensity modulated signals from two different light emitting diodes (LEDs) are detected at one pixel on the image plane, STC allows to decouple them, thus receiving data with no errors. Consequently, STC offers extending the transmission distance. In the layered STC presented here, additional bit streams are aligned in the 2nÃ2n LED array for increasing the transmission rate per symbol duration for the case where the spatial resolution is improved. A prototype of three layered STC is built with an 8Ã8LED array, where each of the LEDs is modulated at 1 kbps and a high-speed camera with IS operating at 1000 fps. Our experimental results validate that additional bit streams (layer-2 and -3), aligned in the layer-1 STC matrix pair, are extracted with no errors when the receiver comes within 155m and 55 m, respectively, from the LED array, without decreasing 210m of the transmission distance of layer-1 bit stream.
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- äœè€ç¿, 岡ç°å, å°æå¥å€ªé, 山鿬ä¹, çå±±æ£æ
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å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, ASN2015-1, pp.1-6, æ±äº¬
- 2015幎5æ
- æ¶²æ¶ãã£ã¹ãã¬ã€çãçšããåºååªäœã§ããããžã¿ã«ãµã€ããŒãžã®æ®åãé²ãã§ããïŒããžã¿ã«æè¡ãå©çšããããšãå¯èœã§ããæ§ã
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å ±ä¿¡å·ã®éç³ã«äŒŽãïŒã³ã³ãã³ãã®å質å£åã課é¡ãšãªãïŒããã§æ¬çš¿ã§ã¯ïŒäººéã®èŠèŠç¹æ§ãèæ
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- 山鿬ä¹
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å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol. 115, no. 2, RCS2015-6, pp. 31-31, , 湯åžé¢ã»æ¹¯åžé·é€š
- 2015幎4æ
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Noise-Enhanced Subthreshold Signal Reception by a Stochastic Resonance Receiver using a Non-Dynamical Device
- H. Tanaka, K. Chiga, T. Yamazato, Y. Tadokoro, S. Arai
- Nonlinear Theory and Its Applications, IEICE, vol.6, no.2, pp.303-312
- 2015幎4æ
- https://doi.org/10.1587/nolta.6.303
- Stochastic resonance (SR) is an interesting phenomenon in that noise enhances system response. Despite attractive phenomenon of SR that noise enhances system response, enhancement of the weak signal below device sensitivity, and few researchers have addressed the SR effect in communication systems. This paper discusses the SR effect in communication systems. We focus on the problem in which communication cannot be established when the received signal strength is below receiver sensitivity. The purpose of this study is to evaluate the bit error rate (BER) performance of the SR receiver and reveal the SR effect in communication systems. We propose an analysis method for the SR receiver using a non-dynamical device that exhibits SR effect. The numerical results show that the SR effect can improve the BER compared to a system without SR. The contribution of the paper is two folds: The first contribution of our present study is that the BER of the SR receiver using a non-dynamical device can analytically be derived. The second contribution of our study is that the number of samples per symbol, the received signal amplitude, and the receiver sensitivity are three important parameters. We further derive the maximum performance gain by the SR system. Although our focus is on primary communication systems; however, our findings can be applied to other systems.
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- 2015幎3æ
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- 2015幎3æ
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Investigation on Relationship Between Communication Distance and Receiving Characteristics in Image-Sensor-Based Visible Light Communication
- Y. Ohira, E. Souke, S. Arai, T. Yamazato, T. Yendo, H. Okada, T. Fujii and K. Kamakura
- RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing (NCSP), pp.274-277, Kuala Lumpur, Malaysia
- 2015幎2æ
- The present paper considers receiving characteristics of an image-sensor-based visible light communication (VLC) usingãan LED and a high-speed-image sensor. In general, a size of LED on an image decreases with increasing a communication distance. In this case, the receiver is difficult to recover data because the intensity of brightness of LED (i.e., luminance) cannot be enough recognized from the image. However,ãthe previous studies about the image-sensor-based VLC have not enough discussed the communication distance and the recognition of LED on the image, i.e., the receiving characteristics. We focus on the communication distance and investigates the relationship between the distance and the receiving characteristics in the image-sensor-based VLC.
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- 2015幎2æ
Visible light communication
- Shlomi Arnon, Jae Kyun Kwon, Sang Hyun Lee, Wen-De Zhong, Zixiong Wang, Mohsen Kavehrad, Weizhi Zhang, Zhengyuan Xu, Chen Gong, Bo Bai, Kang Tae-Gyu, Klaus-Dieter Langer, Shinichiro Haruyama, Takaya Yamazato
- Cambridge University Press
- 2015幎2æ
Outdoor Road-to-Vehicle Visible Light Communication Using On-Vehicle High-Speed Camera
- C. Premachandra, T. Yendo, M. P. Tehrani, T. Yamazato, H. Okada, T. Fujii, M. Tanimoto
- International Journal of Intelligent Transportation Systems Research, vol.13, no.1, pp.28-36
- 2015幎1æ
- https://doi.org/10.1007/s13177-014-0079-y
- We propose a road-to-vehicle Visible Light Communication (VLC) system for ITS. Here, the communication between road and a vehicle is approached using an LED array as a transmitter and an on-vehicle high-speed camera as a receiver. Modulation is conducted at the transmitter by blinking LEDs in high frequency and demodulation is conducted at the receiver by capturing the blinking patterns of the transmitter, by processing the high-speed camera images captured in high frame rate. This paper proposes an effective image processing method for capturing those blinking patterns. Out door communication experiments of the proposed VLC system are also present.
Investigation on Relationship between Communication Distance and Receiving Characteristic in Visible Light Communication Using LED and High-Speed Camera
- E. Souke, Y. Ohira, S. Arai, T. Yamazato, T. Yendo, H. Okada, T. Fujii and K. Kamakura
- Proceedings of 2014 IEEE Workshop on Nonlinear Circuit Networks (NCN'14), pp. 93-94, Tokushima, Japan
- 2014幎12æ
- The present paper considers an optical spatial channel in visible light communication (VLC) using LED and a high-speed camera. In general, the optical spatial channel affects the communication performance. However, the previous studies have not enough discussed the channel for VLC. This study focuses on the communication distance, which is one of channel parameters, and investigates the relationship between the distance and a receiving characteristic in the VLC.
Motion Modeling of Mobile Transmitter for Image Sensor Based I2V-VLC, V2I-VLC, and V2V-VLC
- M. Kinoshita, T. Yamazato, H, Okada, T. Fujii, S. Arai, T. Yendo, K. Kamakura
- IEEE GLOBECOM Workshop on Optical Wireless Communications, pp.535-540, Austin, USA
- 2014幎12æ
- https://doi.org/10.1109/GLOCOMW.2014.7063473
- Visible light communication (VLC) using light-emitting diodes (LEDs) is drawing much attention. There are two types of VLC reception devices, a photodiode and an image sensor. VLC using image sensor is called image sensor based VLC. As the receiver only uses the image sensor pixels that sense LED transmission sources and discards other pixels, including those sensing noise sources, image sensor based VLC is an attractive solution for outdoor mobile applications. However, little evidence is available for channel modeling of image sensor based VLC in mobile outdoor environments, especially for motion modeling of VLC transmitter. In this paper, we propose a motion model of VLC transmitter. In particular, we consider three cases; infrastructure-to-vehicle VLC (I2V-VLC), vehicle-to-infrastructure VLC (V2I-VLC), and vehicle-to-vehicle VLC (V2V-VLC). As a result, we show that the motion model of the VLC transmitter on the captured image for the three aforementioned situations (i.e., I2V-VLC, V2I-VLC, and V2V-VLC) can be expressed in the identical pinhole camera model.
QOSTBC ãçšããç°¡æãªäžç¶åŠçã«ããå調ãã€ããŒã·ã
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- é»åæ
å ±éä¿¡åŠäŒè«æèª, vol.J97-B, no.12, pp.1213-1223
- 2014幎12æ
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ãã¯QOSTBC(Quasi-Orthogonal Space-Time Block Code) ãçšããç°¡æãªäžç¶åŠçã«ããå調ãã€ããŒã·ããšããŠïŒQOSTBC ã®äžçš®ã§ããABBA 笊å·åãè¡ãããä¿¡å·ãåä¿¡ããæ¹åŒã以åã«ææ¡ããïŒãã®æ¹åŒã¯ïŒéä¿¡å±ã§ãããããæç©ºé笊å·åãè¡ãç¹åŸŽããã¡ïŒããã«ããäžç¶å±ã§ã®ä¿¡å·ã®äžŠã¹æ¿ãã«ãã£ãŠåä¿¡å±ã§ã¯ABBA 笊å·ãšç䟡ã®ä¿¡å·è¡åãåŸãŠïŒç¬Šå·åå©åŸãåŸãããïŒäžç¶å±ã«ãããŠã¯ïŒæç©ºé笊å·åãè¡ããªãããããŒã¹ãã³ãä¿¡å·ãžå€æããå¿
èŠããªãïŒIF(Intermediate Frequency) 垯ã§åŠçãå®çµããç¹é·ãæããïŒæ¬è«æã§ã¯ïŒãã®æ¹åŒã«å¯ŸããŠïŒéä¿¡ãããæç©ºéãããã¯ç¬Šå·ãžã®åçŽãªæäœã«ãã£ãŠèª€ãçæ§èœãŸãã¯ä¿¡å·åä¿¡ã«ãããæŒç®éã®æ¹åãè¡ã2 ã€ã®æ¹è¯æ¹åŒã®æ€èšã«, ãããŸã§æªå®æœã§ãã£ãè€æ°ã®ãã£ãã«ã¢ãã«ã«ããæ€èšãå«ããŠïŒQOSTBC ãçšããç°¡æãªäžç¶åŠçã«ããå調ãã€ããŒã·ãã®æ€èšãç·æ¬ããïŒãŸãïŒæ§èœè©äŸ¡ãšããŠã¯åä¿¡å±ã§åŸãããä¿¡å·è¡åã®è©äŸ¡ããã³èª€ãçæ§èœã®èšç®æ©ã·ãã¥ã¬ãŒã·ã§ã³ãè¡ãïŒèšç®æ©ã·ãã¥ã¬ãŒã·ã§ã³ã«ãã£ãŠïŒãã£ãã«ã®ã¢ãã«æ¯ã®æ§èœããã³æ¹è¯æ¹åŒã®å
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Channel Fluctuation Measurement for Image Sensor Based I2V-VLC, V2I-VLC, and V2V-VLC
- M. Kinoshita, T. Yamazato, H, Okada, T. Fujii, S. Arai, T. Yendo, K. Kamakura
- IEEE Asia Pacific Conferece on Circuits and Systems (APCCAS), pp.332-335, Okinawa, Japan
- 2014幎11æ
- https://doi.org/10.1109/APCCAS.2014.7032787
- In image sensor based VLC, transmitter acquisition and tracking are critical issue. However, the fluctuation of the VLC transmitter in the image plane caused by vehicle movement, complicates correct data reception. Therefore, in this paper, we present results of channel fluctuation measurements for infrastructure-to-vehicle VLC (I2V-VLC), vehicle-to-infrastructure VLC (V2I-VLC), and vehicle-to-vehicle VLC (V2V-VLC). We analyze channel fluctuation in terms of optical flow from measured data.
BER Characteristic of Optical-OFDM using OCI
- Y. Goto, I. Takai, T. Yamazato, H. Okada, T. Fujii, S. Kawahito, S. Arai, T. Yendo, K. Kamakura
- IEEE Asia Pacific Conferece on Circuits and Systems (APCCAS), pp.328-331, Okinawa, Japan
- 2014幎11æ
- https://doi.org/10.1109/APCCAS.2014.7032786
- Light-emitting diode (LED) transmitters based optical wireless communication (OWC) systems offer the potential for new generation communication systems. Particularly, an image sensor based OWC systems consist of the LED transmitters and camera receivers are expected to contribute to intelligent transport system (ITS) for driving supports. For high achievable data rates, orthogonal frequency division multiplexing (OFDM) based OWC systems have attracted a great deal of attention. Despite attractive features of optical OFDM, only few attempts have so far been made to adopt it as a modulation scheme of an image sensor based OWC system. There remains a need for an evaluation of adopting an optical OFDM to the image sensor based OWC systems. Another important issue needs to be addressed is the performance degradation due to a frequency response of an actual image sensor device, especially a signal attenuation loss in higher frequency. In addition to such loss, a narrow band noise generated by its circuits also degrades the performance. The purpose of this paper is to investigate BER performances of the optical-OFDM using an actual image sensor device, the optical communication image sensor (OCI). From simulation results, it is found that the frequency response and the narrowband noise at 12MHz of the OCI lead to the significant reduction of BER performances. Additionally, the results shows that ACO-OFDM shows a little better performance compared to DCO-OFDM with the same bandwidth efficiency.
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- 2014幎11æ
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å ±éä¿¡åŠäŒ åºç€ã»å¢çãœãµã€ãšãã£å€§äŒ, A-5-1, p.83, 埳島
- 2014幎9æ
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- 2014幎9æ
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- 2014幎9æ
- ã€ã¡ãŒãžã»ã³ãµãçšããè·¯è»éã»è»è·¯éã»è»è»éå¯èŠå
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å ±ãæã£ãæ£ãããã¯ã»ã«ã®éžæãå°é£ãšãªã£ãŠããŸãïŒããã§ïŒæ¬çš¿ã§ã¯èªåè»ã¢ããªã±ãŒã·ã§ã³ã®ããã®ã€ã¡ãŒãžã»ã³ãµãçšããå¯èŠå
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An Analysis Method of a Stochastic Resonance Receiver using a Schmitt Trigger
- H. Tanaka, K. Chiga, T. Yamazato, Y. Tadokoro, and S. Arai
- International Symposium on Nonlinear Theory and its Application (NOLTA), pp.193-196, Luzern, Switzerland
- 2014幎9æ
- Stochastic resonance (SR) enhances system responses by increasing noise. By applying SR to a receiver, a subthreshold signal not receivable by a conventional linear receiver could be received. Previously, we proposed an analysis method of the SR receiver using a comparator, and evaluated its bit error rate performance. The comparator is known as a simple non-dynamical system exhibiting SR. However, a dynamical system can have better performance since it has a memory effect. In this sense, we propose an analysis method of the SR receiver using a Schmitt trigger known as a simple dynamical system, and evaluate its bit error rate performance. A performance comparison of the comparator and the Schmitt trigger is also shown.
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- 2014幎9æ
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SNR Improvement by Stochastic Resonance Receiver for Subthreshold Signal in Radio Frequency
- K. Chiga, H. Tanaka, T. Yamazato, Y. Tadokoro, S. Arai
- International Symposium on Nonlinear Theory and its Application (NOLTA), Luzern, Switzerland
- 2014幎9æ
- Stochastic Resonance (SR) is well known as a phenomenon in which the weak signal in a nonlinear system can be detected by added noise. We consider the application of SR phenomenon to a wireless communication system. The receiver using SR phenomenon can detect the subthreshold signal which is not detectable by the conventional receiver. The effect of SR receiver has been verified, but it has never been verified in radio frequency which is used by a wireless system. In this paper, we consider the implementation of SR System for Radio Frequency and evaluate its performance of Signal to Noise Ratio (SNR).
Image Sensor Based Visible Light Communication and Its Application to Pose, Position, and Range Estimations
- T. Yamazato, S. Haruyama
- IEICE Transactions on Communications, vol.E97-B, no.9, pp.1759-1765
- 2014幎9æ
- https://doi.org/10.1587/transcom.E97.B.1759
- This study introduces an image sensor based visible light communication (VLC) and its application to pose, position, and range estimations. There are two types of visible-light receiver: a photodiode and an image sensor. A photodiode is usually used as a reception device of VLC, and an image sensor consisting of a large number of pixels can also be used as a VLC reception device. A photodiode detects the signal intensity of incoming light, while an image sensor not only detects the incoming signal intensity but also an accurate angle of arrival of light emitted from a visible light transmitter such as a white LED light. After angles of arrival of light are detected by an image sensor, positioning and data reception can be performed. The ability of an image sensor to detect an accurate angle of arrival will provide attractive applications of VLC such as pose, position calculation, and range estimation. Furthermore, because the image sensor has the ability to spatially separate sources, outdoor positioning even with strong sunlight is possible by discarding the associated pixels of noise sources.
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- 2014幎8æ
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- 第27å åè·¯ãšã·ã¹ãã ã¯ãŒã¯ã·ã§ãã, pp.116-120, 淡路島
- 2014幎8æ
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- é»åæ
å ±éä¿¡åŠäŒè«æèª, vol.J97-B, no.8, pp.695-696
- 2014幎8æ
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- é»åæ
å ±éä¿¡åŠäŒè«æèª, vol.J97-B, no.7, pp.536-545
- 2014幎7æ
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Image-sensor-based Visible Light Communication for Automotive Applications
- T. Yamazato, I. Takai, H. Okada, T. Fujii, T. Yendo, S. Arai, M. Andoh, T. Harada, K. Yasutomi, K. Kagawa, S. Kawahito
- IEEE Communications Magazine, vol.52, no.7, pp.88-97
- 2014幎7æ
- https://doi.org/10.1109/MCOM.2014.6852088
- The present article introduces VLC for automotive applications using an image sensor. In particular, V2I-VLC and V2V-VLC are presented. While previous studies have documented the effectiveness of V2I and V2V communication using radio technology in terms of improving automotive safety, in the present article, we identify characteristics unique to image-sensor-based VLC as compared to radio wave technology. The two primary advantages of a VLC system are its line-of-sight feature and an image sensor that not only provides VLC functions, but also the potential vehicle safety applications made possible by image and video processing. Herein, we present two ongoing image-sensor-based V2I-VLC and V2VVLC projects. In the first, a transmitter using an LED array (which is assumed to be an LED traffic light) and a receiver using a high-framerate CMOS image sensor camera is introduced as a potential V2I-VLC system. For this system, real-time transmission of the audio signal has been confirmed through a field trial. In the second project, we introduce a newly developed CMOS image sensor capable of receiving highspeed optical signals and demonstrate its effectiveness through a V2V communication field trial. In experiments, due to the high-speed signal reception capability of the camera receiver using the developed image sensor, a data transmission rate of 10 Mb/s has been achieved, and image (320 Ã 240, color) reception has been confirmed together with simultaneous reception of various internal vehicle data, such as vehicle ID and speed.
M-ary Modulation Scheme Based on Separation of Deterministic Chaotic Dynamics for Noncoherent Chaos-Based Communications
- S. Arai, Y. Nishio, T. Yamazato
- NOLTA, IEICE, vol. 5, no.2, pp.210-221
- 2014幎4æ
- https://doi.org/10.1587/nolta.5.210
- The present paper proposes a novel M-ary modulation scheme based on separation and reconstruction of deterministic chaotic dynamics for noncoherent chaos-based communications. The M-ary modulation scheme can transmit b-bit data at a time by using M=2b distinct sequences. In order to generate M distinct sequences and recover b-bit data, the proposed system separates the chaotic dynamics having the chaotic sequence by using M interleavers, and reconstructs the original sequence based on the chaotic dynamics from the separated one by using M deinterleavers. In advance, each data symbol among M symbols is allocated to each interleaver-deinterleaver pair. The transmitter selects an interleaver corresponding to a data symbol and separates the order of samples of the chaotic sequence using the selected interleaver. The receiver feeds the received sequence into all M deinterleavers and outputs M reconstructed sequences. The proposed system can reconstruct the original chaotic sequence only when the correct deinterleaver, which becomes paired with the interleaver, is selected. Therefore, the receiver can recover b-bit data by analyzing the chaotic dynamics of each reconstructed sequence. We carry out computer simulations and evaluate performances of the proposed M-ary modulation scheme.
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- 2014幎3æ
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- 2014幎3æ
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- 2014幎3æ
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å ±éä¿¡åŠäŒèª Vol.97 No.3, pp.240-246
- 2014幎3æ
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Preliminary Study on LED VLC with Simple SR Receiver Using Schmitt Trigger
- H. Yokota, S. Arai, T. Yamazato and Y. Tadokoro
- RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing (NCSP), pp. 61-64., Hawaii, USA
- 2014幎2æ
- The present paper focuses on an application of Stochastic Resonance (SR) for an LED visible light communication (LED-VLC) receiver. SR is well-known as a phenomenon, which enhances the response by additive noise. We consider that a weak optical signal, which is distorted due to an influence of ambient light noise, can be detected by using SR system. This study makes a simple SR circuit for LED VLC and performs its circuit experiment for exploring the possibility and availability of the LED-VLC receiver using SR system.
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- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, ITS2013-39, pp.55-60, æå¹
- 2014幎2æ
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Multiple LED Arrays Acquisition for Image-Sensor-Based I2V-VLC Using Block Matching
- S. Arai, Y. Shiraki, T. Yamazato, H. Okada, T. Fujii, T. Yendo
- IEEE Consumer Communications and Networking Conference (CCNC), pp.605-610, Las Vegas, USA
- 2014幎1æ
- https://doi.org/10.1109/CCNC.2014.6866634
- The present paper proposes a novel multiple-LED-arrays acquisition for an infrastructure-to-vehicle visible light communication (I2V-VLC) using LED arrays (transmitter) and an in-vehicle high-speed image sensor (receiver). In order to achieve a robust detection of LED arrays, we employ the block matching algorithm, which is a way of finding a corresponding position between two successive frames. The proposed method divides a captured image into a number of small domains (blocks) and determines if the LED array is present or absent using the block matching. We perform I2V-VLC experiments with multiple-LED arrays and evaluate the acquisition capability of the proposed method.
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A Study on Simple LED-VLC Flashlight Transmitter for Disaster Situation
- K. Miyazaki, Y. Ohira, S. Arai, T. Yendo, T. Yamazato, H. Okada, T. Fujii
- Proceedings of 2013 IEEE Workshop on Nonlinear Circuit Networks (NCN'13), Tokushima, Japan
- 2013幎12æ
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Utilization of Spatio-temporal Image for LED Array Acquisition in Road to Vehicle Visible Light Communication
- S. Usui, T. Yamazato, S. Arai, T. Yendo, T. Fujii, H. Okada
- 20th World Congress on Intelligent Transport Systems , Tokyo, Japan
- 2013幎10æ
- In this paper, we focus attention on visible light communication systems using an LED array as a transmitter and a high-speed camera as a receiver for road-to-vehicle communications (R2V-VLC) in intelligent transport systems. To implement R2V-VLC, it is necessary for the receiver to search the target LED array from the captured images (LED array acquisition) before data demodulation. We propose a new approach for LED array acquisition. We focus on spatio-temporal image and spatio-temporal cross-section image and show LED array in the spatio-temporal image has high time-gradient value and low space-gradient value. Using such characteristic gradient values, we propose new LED array acquisition method. As the results of the experiment in driving situation, we can achieve acquisition miss rate = 0%.
Accuracy Improvement by Phase Only Correlation for Distance Estimation Scheme for Visible Light Communications Using an LED Array and a High-speed Camera
- A. Ohmura, T. Yamazato, H. Okada, T. Fujii, T. Yendo, S. Arai
- 20th World Congress on Intelligent Transport Systems, Tokyo, Japan
- 2013幎10æ
- In this paper, we focus on a distance estimation scheme using camera. Our distance estimation scheme is based on triangulation. The accuracy of camera based scheme is governed by resolution of a camera, or equivalently the size of pixel. Therefore we introduce phase only correlation (POC) to estimate with subpixel accuracy. As a result of experiment, we will show that our scheme achieves less than 0.3m estimation error at the distance of 60m. By using POC, the resolution of estimation reaches nearly 0.02 pixel, much less than one pixel.
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- 2013幎9æ
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Implementation of Bi-Polar Pulse SR Receiver Using Schmitt Trigger and Evaluation of its Performance
- K. Chiga, H. Tanaka, T. Yamazato, Y. Tadokoro, S. Arai
- International Symposium on Nonlinear Theory and its Application (NOLTA), pp.269-271, Santa Fe, USA
- 2013幎9æ
- We consider an application of Stochastic Resonance to wireless communication system. Stochastic Resonance (SR) is well known as a phenomenon in which weak signal in nonlinear system can be detected by added noise. A receiver using Stochastic Resonance (SR Receiver) can detect a weak signal which is not detectable in the conventional receiver. In this paper, we consider the implementation of bi-polar pulse SR Receiver using Schmitt Trigger and evaluate the performance in Signal-to-Noise Ratio (SNR) and Bit Error Rate (BER).
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Letâs Search IEICE Contents through New Meta-Data System âI-Scoverâ!
- T. Yamazato
- IEICE Global Plaza, No.55, Aug., 2013
- 2013幎8æ
- IEICE launched the new metadata search system called âI-Scoverâ on April 3, 2013[1]. For the time being, I-Scover provides the metadata search service of all papers published in IEICE transactions covering from the first edition published in 1968 up to the present edition, Technical Reports (from 2006) and international conference papers of ISPA and EMC. The total number of searchable contents reaches 150,000 as listed in Table.1. This article briefly introduces I-Scover. Before going to the details, let me start with a quiz. What phrase do you guess if you say âI-Scoverâ for three times?
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- 第26å åè·¯ãšã·ã¹ãã ã¯ãŒã¯ã·ã§ãã è«æé, pp. 7-11, å
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- 2013幎7æ
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- 2013幎7æ
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- 2013幎7æ
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éä¿¡ã«ãããŠïŒLED ã¢ã¬ã€ããæ¢ç¥ã®ããŒã¿ãã¿ãŒã³ãéä¿¡ããããšã§éä¿¡ãšåæã«æž¬è·ãè¡ãã·ã¹ãã ãææ¡ããïŒèµ°è¡æã«ãããè»äž¡ã®æ¯åã«ããæž¬è·æ§èœãäœäžããåé¡ã«ã€ããŠïŒäœçžéå®çžé¢æ³ãçšããææ³ã«ãã解決ãå³ãïŒ
Performance Evaluation of Stochastic Resonance Receiver for the Multi Carrier Detection
- H. Tanaka, K. chiga, T. Yamazato, Y, Tadokoro, S. Arai
- NANOENERGY2013, pp.58-59, Perugia, Italy
- 2013幎7æ
- Stochastic Resonance (SR), known as a noise-enhanced phenomenon, can improve the performance of communication systems. By applying SR in the receiver, it is possible to detect a weak signal that is not detectable in the traditional linear receiver. In the SR systems, the input of multi-carrier has not ever been discussed. So this paper proposes the SR receiver for multi-carrier detection and evaluates its Bit-Error-Rate (BER) performanceïŒ
Image Sensor based Visible Light Communication for Automotive Applications
- T. Yamazato, I. Takai, H. Okada, T. Fujii, T. Yendo, S. Arai, M. Andoh, K. Yasutomi, K. Kagawa, S. Kawahito
- International Symposium on Optical Wireless Communications, Beijing Jade Palace Hotel, China
- 2013幎6æ
- This talk introduces visible light communication (VLC) for automotive applications using an image sensor. In particular, vehicle-to-infrastructure visible light communication (V2I-VLC) and vehicle-to-vehicle visible light communication (V2V-VLC) are presented. Previous studies have documented the effectiveness of V2I and V2V communication using radio technology for improving automotive safety. In this talk, I identify characteristics unique to the introduced image sensor based VLC as compared to radio wave technology. The advantages of VCL are twofold: the line-of-sight feature of visible light links and an image sensor that provides not only the VLC function but also vehicle safety applications using image and video processing. We present two on-going image sensors based V2I-VLC and V2V-VLC projects.
Channel Information Estimation for Error Correcting Code in Road-to-Vehicle Visible Light Communication Systems
- H. Okada, S. Misawa, T. Yamazato, T. Fujii, T. Yendo
- IEEE International Symposium on Wireless Vehicular Communications (WiVeC), Dresden, Germany
- 2013幎6æ
- https://doi.org/10.1109/wivec.2013.6698229
- This paper focuses on a road-to-vehicle visible light communication (VLC) system using LED traffic lights and high-speed cameras on cars. So as to improve the transmission reliability, an error correcting code like a low-density parity-check (LDPC) is applied to the road-to-vehicle VLC system. The decoder of the LDPC code needs channel information in order to maximize decoding performance. Usually, it is calculated from a signal-to-noise ratio (SNR) or bit error rate (BER) of a channel, where noise is a dominant factor of the channel characteristic. In the road-to-vehicle VLC system, not noise but interference among LEDs decides the channel characteristic. In this paper, we propose a channel information estimation method for the road-to-vehicle VLC system. The proposed method estimates a signal-to-interference ratio (SIR) from the receiving image, and calculates the channel information using the SIR. The proposed method is evaluated by experiment. As a result, the proposed method can achieve almost the same performance with the optimum case, and then maximize the decoding performance.
Interpixel Interference Cancellation Method for Road-to-Vehicle Visible Light Communication
- T. Kasashima, T. Yamazato, H. OKada, T. Fujii, T. Yendo, S. Arai
- IEEE International Symposium on Wireless Vehicular Communications (WiVeC), Dresden, Germany
- 2013幎6æ
- https://doi.org/10.1109/wivec.2013.6698237
- This paper aims to improve the transmission distance for the road-to-vehicle visible light communication system (R2V-VLC) using LED array and high-speed camera by reducing interference caused at the receiver. As we can transmit multiple data using LED array and high-speed camera, parallel data transmission can be possible. However, due to the diffusion of LED and the finiteness of the pixel size of image sensor, the focused LED will affect not only the actual corresponding pixel but also its surrounding pixels. We call this phenomenon as âinterpixel interference (IPI)â and it causes degradation in error rate performance. To mitigate the IPI, we propose IPI cancellation scheme for the R2V-VLC system. As the results of the experiment, we can extend the error-free distance from 40m to 60m by the IPI cancellation.
Discover IEICE Contents Using I-Scover
- T. Yamazato
- IEICE Communications Society – GLOBAL NEWSLETTER Vol. 37, No. 2, Jun., 2013.
- 2013幎6æ
- The IEICE launched new metadata search system called I-Scover (http://i-scover.ieice.org) from April 3rd, 2013. I-Scover provides metadata search of the IEICE transactions papers (from its first edition published in 1968), Technical Reports (from 2006) and international conference papers of ISPA and EMC. The total of the contents that can be searched is more than 150,000. This article briefly introduces I-Scover. Before going to detail, let me start with a quiz. What phrase do you guess if you say I-Scover for three times?
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- 2013幎3æ
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- 2013幎3æ
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- 2013幎3æ
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Intensity Estimation Method of LED Array for Visible Light Communication
- T. Ito, T. Yendo, S. Arai, T. Yamazato, H. Okada, T. Fujii
- Proc. SPIE 8663, Video Surveillance and Transportation Imaging Applications, 86630V, Burlingame, California, USA
- 2013幎3æ
- doi:https://doi.org/10.1117/12.2005738
- This paper focuses on a road-to-vehicle visible light communication (VLC) system using LED traffic light as the transmitter and camera as the receiver. The traffic light is composed of a hundred of LEDs on two dimensional plain. In this system, data is sent as two dimensional brightness patterns by controlling each LED of the traffic light individually, and they are received as images by the camera. Here, there are problems that neighboring LEDs on the received image are merged due to less number of pixels in case that the receiver is distant from the transmitter, and/or due to blurring by defocus of the camera. Because of that, bit error rate (BER) increases due to recognition error of intensity of LEDs To solve the problem, we propose a method that estimates the intensity of LEDs by solving the inverse problem of communication channel characteristic from the transmitter to the receiver. The proposed method is evaluated by BER characteristics which are obtained by computer simulation and experiments. In the result, the proposed method can estimate with better accuracy than the conventional methods, especially in case that the received image is blurred a lot, and the number of pixels is small. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
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Development of Simple Simulator for Visible Light Communication Using LED and Camera
- T. Fukumoto, S. Arai, T. Yendo, T. Yamazato, H. Okada and T. Fujii
- RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing (NCSP), pp. 33-36, Hawaii, USA
- 2013幎3æ
- This paper develops a simple simulator for the visible light communication (VLC) system using a LED traffic light and a camera for intelligent transport systems (ITS). We use image processing techniques for simulating effects of optical spatial channel which is a unique channel in VLC. We describe a system model of the VLC simulator and perform the simulation with various parameters of the image processing.
Performance Analysis of Error-Correcting Method Using Separation of Chaos for Noncoherent Chaos Communications
- S. Arai, Y. Nishio and T. Yamazato
- RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing (NCSP), pp. 225-228, Hawaii, USA
- 2013幎3æ
- This paper analyzes the performance of the error-correcting method, which was proposed in the previous research, using the separation and the reconstruction of chaos for noncoherent chaos communications. Especially, we focus on a number of transmitting data and a combination of symbols (i.e., data pattern). We consider that the capability of the error correction depends on the number of data and the data pattern because the proposed method performs the error correction using successive data symbols. This study performs simulations for the number of data and the data pattern, and evaluates BER performance of the proposed method.
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- 2013幎3æ
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- 第5åè€éã³ãã¥ãã±ãŒã·ã§ã³ãµã€ãšã³ã¹ç ç©¶äŒ, CCS-2012-038, æ±äº¬
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å ±éä¿¡åŠäŒè«æèª, vol.J96-B, no.2, pp.191-201
- 2013幎2æ
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眮ã«å¶éãããããä¿¡å·æ©ãªã©ã®éä¿¡æ©ã«åžžã«é©å¿ããŠããããã§ã¯ãªãã£ãïŒãã®å¶éã解決ããããã«ïŒãéç³ç¬Šå·åããšãã笊å·åæ¹åŒãææ¡ããïŒææ¡æ¹åŒã§ã¯çŽäº€å€æãçšããïŒè€æ°ã®LEDã«åäžã®ããŒã¿ãå²ãåœãŠïŒãããäžã€ã®LEDãšèŠãªãïŒãã®ãšãã®åäžã®ããŒã¿ãå²ãåœãŠãLEDã®æ°ãå€åãããããšã§å空éåšæ³¢æ°æåã«æ
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A Study on the Simulator Development for Visible Light Communication Using LED and Camera
- T. Fukumoto, S. Arai, T. Yendo, T. Yamazato, H. Okada and T. Fujii
- Proceedings of IEEE Workshop on Nonlinear Circuit Networks (NCN'12), pp. 124-127, Tokushima, Japan
- 2012幎12æ
- This paper develops a simple simulation program for visible light communication (VLC) systems using LED (Transmitter) and a camera (Receiver). In the simulation, we generate an image of LED array transmitter which consists of LEDs arranged in a square matrix. In addition, effects of optical spatial channel, which is a unique channel in VLC, are constructed by using image processing techniques. We describe a system model of the VLC simulator and carry out the simulation with various parameters of the image processing.
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- 2012幎12æ
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å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, CS2012-83, pp.71-75, çŠäºç
- 2012幎12æ
High-speed Transmission of Overlay Coding for Road-to-Vehicle Visible Light Communication Using LED Array and High-Speed Camera
- S. Nishimoto, T. Yamazato, H. Okada, T. Fujii, T. Yendo, S. Arai
- IEEE GLOBECOM Workshop on Optical Wireless Communications, pp.1234-1238, Anaheim, USA
- 2012幎12æ
- https://doi.org/10.1109/GLOCOMW.2012.6477757
- This paper aims to the improve the data rate for the visible light communication system using LED array and high-speed camera. Previously, we have proposed the decoding algorithm using inverted signals for driving situation. However, using this method the data rate become a half, because we transmit original signals and inverted signals alternately for LED array tracking. In this paper, we propose the data rate improving method for overlay coding which is coding method that overlay two data which are called as the long range data and the short range data. In the proposed method, for the long range data, we transmit original signals and inverted signals alternately. On the other hand, for the short range data, we transmit only original signals while we transmit inverted signals of long range data. We confirm that we can improve data rate as compared with the previous method.
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- 2012幎12æ
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A Study on Error-Correcting Method for Noncoherent Chaos Communications
- S. Arai, Y. Nishio, T. Yamazato
- Japan-Korea Joint Workshop on Complex Communication Sciences, Seoul, Korea
- 2012幎11æ
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- 2012幎11æ
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Improvement of Error-Correcting Method Based on Chaotic Dynamics for Noncoherent Chaos Communications
- S. Arai, Y. Nishio, T. Yamazato
- International Symposium on Nonlinear Theory and its Applications (NOLTA), pp.801-804, Palma, Majorca, Spain
- 2012幎10æ
- This paper focuses on characteristics of the chaotic dynamics and improves our previous errorcorrecting method using them for noncoherent chaos communications. Our previous method is performed by using a chaotic sequence generated according to the chaotic dynamics. In this case, it is very difficult to recover data without a successive sequence based on the chaotic dynamics. We focus on this feature and consider that an improved method separates and reconstructs the chaotic dynamics of the sequence according to a specific rule. Namely, the separation and reconstruction of the chaotic dynamics can be applied for our improved method as additional information. As results of simulations, we have confirmed that the advantage gained in BER performance of our improved method is about 2–2.5 dB compared to a conventional method (without coding).
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æºãšåä¿¡æ©ãšããŠã®é«é床ã«ã¡ã©éã®è·é¢ãæšå®ããïŒã«ã¡ã©ã«ããåŸãããç»åããè·é¢ãæšå®ãããïŒãã®éç»çŽ ã®åäœã§ãããã¯ã»ã«ã¬ãã«ã§ã®æšå®ã§ã¯è·é¢æšå®ç²ŸåºŠãäžååã§ããïŒãã£ãŠïŒãã¯ã»ã«ããå°ããåäœã§ãããµããã¯ã»ã«ã¬ãã«ã§ã®ç»ååŠçæè¡ãå¿
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A Study on Cluster Lifetime in Multi-Hop Wireless Sensor Networks with Cooperative MISO Scheme
- Z. Huang, H. Okada, K. Kobayashi, M. Katayama
- Journal of Communications and Networks, vol.14, no.4, pp.443-450
- 2012幎8æ
- https://doi.org/10.1109/JCN.2012.6292251
- As for cluster-based wireless sensor networks (WSNs), cluster lifetime is one of the most important subjects in recent researches. Besides reducing the energy consumptions of the clusters, it is necessary to make the clusters achieve equal lifetimes so that the whole network can survive longer. In this paper, we focus on the cluster lifetimes in multi-hop WSNs with cooperative multi-input single-output scheme. With a simplified model of multi-hop WSNs, we change the transmission schemes, the sizes and transmission distances of clusters to investigate their effects on the cluster lifetimes. Furthermore, linear and uniform data aggregations are considered in our model. As a result, we analyze the cluster lifetimes in different situations and discuss the requirements on the sizes and transmission distances of clusters for equal lifetimes.
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- 山鿬ä¹
- å¹³æ24å¹ŽåºŠå·¥åŠæè²ç ç©¶è¬æŒäŒè¬æŒè«æéã8-331, èæµŠå·¥æ¥å€§åŠè±æŽ²ãã£ã³ãã¹
- 2012幎8æ
ãã³ã³ããŒã¬ã³ãã«ãªã¹éä¿¡ã·ã¹ãã ã®ããã®ã«ãªã¹ãã€ããã¯ã¹ã®åé¢ãå©çšãã誀ãèšæ£ææ³ã®è©äŸ¡
- èäºäŒžå€ªé, è¥¿å°Ÿè³æ, 山鿬ä¹
- 第25å åè·¯ãšã·ã¹ãã ã¯ãŒã¯ã·ã§ãã è«æé, pp. 261-266, 淡路島
- 2012幎7æ
LEDã¢ã¬ã€ãšé«é床ã«ã¡ã©ãçšããè·¯è»éå¯èŠå
éä¿¡ã«ãããéç³ç¬Šå·åã®äŒéé床æ¹åææ³
- è¥¿æ¬æ©è¶éŠïŒå±±éæ¬ä¹ïŒå²¡ç°åïŒè€äºä¿åœ°ïŒåéç¥åïŒèäºäŒžå€ªé
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.112, no.148, ITS2012-9, pp.19-24, åå€å±
- 2012幎7æ
- æ¬çš¿ã§ã¯éä¿¡æ©ã«LED ã¢ã¬ã€ïŒåä¿¡æ©ã«è»èŒé«é床ã«ã¡ã©ãçšããå¯èŠå
éä¿¡ãèããïŒè»äž¡èµ°è¡æã®éä¿¡ãå®çŸããããã«å転信å·ãçšãã埩å·ã¢ã«ãŽãªãºã ãææ¡ãããŠããïŒãšããããã®æ¹æ³ã§ã¯ïŒéä¿¡æ©ã®è¿œè·¡ã®ããã«å
ä¿¡å·ãšãããå転ãããä¿¡å·ã亀äºã«éä¿¡ããŠããããïŒäŒéé床ãååã«ãªã£ãŠããŸãïŒæ¬çš¿ã§ã¯ïŒäºã€ã®æ
å ±ãéç³ãã笊å·åæ¹åŒã§ããéç³ç¬Šå·åã«é©ããäŒéé床æ¹åææ³ãææ¡ãïŒãã®ç¹æ§ãè©äŸ¡ããïŒ
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éä¿¡ãçšããè·¯è»ééä¿¡ã»æž¬è·çµ±åã·ã¹ãã
- 倧ææå¯ïŒå±±éæ¬ä¹ïŒå²¡ç°åïŒè€äºä¿åœ°ïŒåéç¥åïŒèäºäŒžå€ªé
- é»åæ
å ±éä¿¡åŠäŒæè¡ ç ç©¶å ±å, USN2012-9, pp.63-68, è±æ©
- 2012幎5æ
- éè·¯ã«èšçœ®ããLED ã¢ã¬ã€ããèµ°è¡è»äž¡ã«åãã£ãŠããŒã¿äŒéãè¡ãè·¯è»éå¯èŠå
éä¿¡ã§ã¯ïŒåä¿¡æ©ã«é«é床ã«ã¡ã©ãçšããããšã§èµ°è¡è»äž¡ã®æ¯åãäœæžã§ãïŒããã¹ããªããŒã¿åä¿¡ãã§ããïŒãã®è·¯è»éå¯èŠå
éä¿¡ã«ãããŠïŒLED ã¢ã¬ã€ããæ¢ç¥ã®ããŒã¿ãã¿ãŒã³ãéä¿¡ããããšã§éä¿¡ãšåæã«æž¬è·ãè¡ãã·ã¹ãã ãææ¡ããïŒ
A Study on Cluster Partitioning with Cooperative MISO Scheme in Wireless Sensor Networks
- Z. Huang, H. Okada, M. Katayama, T. Yamazato
- International Journal of Distributed Sensor Networks, vol.2012, Article ID 490823, 9 pages
- 2012幎3æ
- https://doi.org/10.1155/2012/490823
- This paper addresses the cluster partitioning problem in wireless sensor networks deployed in a continuous area. We present the model of the network and describe its operational details firstly. Both single-hop and multi-hop transmissions with cooperative Multi-Input Single-Output (MISO) scheme are considered for the inter-cluster communications. Besides, uniform and linear data fusions are discussed. Then the calculations of energy consumptions are derived. Different from other researches, the energy consumptions of intra-cluster communication in each cluster are included and modeled as functions of the cluster size. Finally, we simulate all possible cluster partitions by changing the numbers of clusters and cooperative transmitting nodes, and find the maximal network lifetimes. As a result, the relationships between cluster partitions and network lifetimes are clarified in different situations.
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- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒïŒA-2-34, p.79, 岡山
- 2012幎3æ
- 確çå
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- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, B-10-104, p.427, 岡山
- 2012幎3æ
- æã
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å ±ã®æäŸãç®çãšããç ç©¶ãè¡ã£ãŠããïŒå¯èŠå
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- å°ŸåŽç¿å€ª, èäºäŒžå€ªé, 山鿬ä¹, è¥¿å°Ÿè³æ
- é»åæ
å ±éä¿¡åŠäŒ ç·åå€§äŒ è¬æŒè«æé, no. A-2-35, p. 80, 岡山
- 2012幎3æ
- ããéç·åœ¢ã·ã¹ãã ã«ãã€ãºãå ããããšã«ãã£ãŠïŒã·ã¹ãã ã®å¿çæ§ã確ççã«åäžããçŸè±¡ã確çå
±é³Ž(Stochastic Resonance: SR) ãšåŒã¶ [1]ïŒSR ã¯æ§ã
ãªå·¥åŠã·ã¹ãã ãžã®å¿çšãæåŸ
ãããŠããïŒãã®ããã«ã¯ãã€ãºãš SR ã®é¢ä¿ã詳ãã調æ»ããå¿
èŠãããïŒããã§æ¬ç ç©¶ã§ã¯ïŒSR ã®ç ç©¶ã§åºãçšããããŠããã2 éäºæžããã³ã·ã£ã«ç³»ããæ¡åŒµãããã4 éäºæžããã³ã·ã£ã«ç³»ãã§ã® SR çŸè±¡ãè§£æããïŒå
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- æ
å ±åŠçåŠäŒç ç©¶å ±å, vol.2012-MBL-61, no.31, pp.1-8, æ±äº¬
- 2012幎3æ
- 倪éœãšãã«ã®ãŒãå©çšããç¡ç·ã»ã³ãµãããã¯ãŒã¯ããšãã«ã®ãŒå©çšã®å¹çåã«ãã£ãŠå€©åïŒæŒå€ã«ãããåžžã«é«ããã±ããäŒéçã§éçšããããšãç®æããŠããïŒãããã¯ãŒã¯å
šäœã®æ¶è²»ãšãã«ã®ãŒãæé©åããæ¹æ³ãšããŠïŒããŒã¿éä¿¡æã«ããŒããããŒã¿ã®äžç¶ãè¡ãååäŒéæ¹åŒãããïŒãããïŒçºé»éã®å€åãèæ
®ããªãå ŽåïŒæå€©æãå€éã«ããŒãã®é»æ± åãã«ãã£ãŠãã±ããäŒéçãäœäžããŠããŸãïŒæ¬çš¿ã§ã¯ïŒçºé»éäºæž¬ãå©çšããäžç¶ããŒãéžæææ³ãææ¡ãïŒå€©åå€åã®åœ±é¿ã軜æžããããšã§ïŒèŠæ±ãããé«ããã±ããäŒéçã®ç¶æãå³ãïŒ
Analysis of Stochastic Resonance in Quadruple-Well Potential
- S. Arai, S. Ozaki, T. Yamazato, Y. Nishio
- RISP International Workshop on Nonlinear Circuits, Communications and Signal Processing (NCSP), pp.60-63, Honolulu, Hawaii, USA
- 2012幎3æ
- This paper analyzes a stochastic resonance (SR) in a quadruple-well potential, which extended the SR in a doublewell potential, to control of SR. For achieving the control of SR, it is important to analyze the state of the SR by injecting the noise. In this study, we calculate existence probabilities of the SRâs state to analyze how the state changes by a noise intensity.
Preliminary Study on BPSK Receiver using Stochastic Resonance
- H. Tanaka, T. Yamazato, S. Arai
- RISP International Workshop on Nonlinear Circuits, Commuations and Signal Processing (NCSP), pp.64-67, Honolulu, Hawaii, USA
- 2012幎3æ
- Stochastic Resonance (SR), known as a noise-enhanced phenomenon, can improve the performance of commutation systems. In this paper, we present a preliminary study on SR and its application to BPSK receiver. We discuss a basic question arises from a receiver using SR that shall we perform SR process in a radio-frequency (RF) band or in a baseband (BB)? As results, we found that SR process in RF band shows better Bit Error Rate (BER) performance. This comes from the fact that a down conversion process that reduces the signal amplitude causes weak noise suppression by SR. While a double frequency term obtained also by the down conversion process do not affect much to the noise reduction performance.
LEDã¢ã¬ã€ãšé«é床ã«ã¡ã©ãçšããè·¯è»éå¯èŠå
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- ç¬ å¶éä¹, 山鿬ä¹, 岡ç°å, è€äºä¿åœ°, åéç¥å, èäºäŒžå€ªé
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, ITS2011-38, pp.129-134, æå¹
- 2012幎2æ
- æ¬çš¿ã§ã¯éä¿¡æ©ã«LEDã¢ã¬ã€ïŒåä¿¡æ©ã«é«é床ã«ã¡ã©ãçšããå¯èŠå
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å ±ã衚çŸããŠãããïŒç¹ç¯ããŠããLEDã®å
ãåšå²ã«æ¡æ£ãïŒé£æ¥ã®LEDã«åœ±é¿ãäžããŠããŸãåé¡ãããïŒèª€ãçç¹æ§å£åã®åå ãšãªãïŒããã§ãã®åé¡ãLEDå
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- åå培ïŒå±±éæ¬ä¹ïŒèäºäŒžå€ªéïŒå²¡ç°åïŒåéç¥åïŒè€äºä¿åœ°
- é»åæ
å ±éä¿¡åŠäŒè«æèª, vol.J95-B, no.2, pp.326-336
- 2012幎2æ
- æ¬è«æã§ã¯ïŒLEDä¿¡å·æ©ã«èŠç«ãŠãLEDã¢ã¬ã€ãéä¿¡æ©ã«ïŒè»èŒé«é床ã«ã¡ã©ãåä¿¡æ©ã«çšããå¯èŠå
è·¯è»ééä¿¡ã·ã¹ãã ã«ã€ããŠèããïŒå®ç°å¢ã«ãããè·¯è»ééä¿¡ã§ã¯ïŒè»äž¡ãèµ°è¡ããŠããå Žåã§ãããã¹ãã«LEDä¿¡å·æ©ïŒLEDã¢ã¬ã€ïŒã®ææãã§ãéä¿¡ã§ããªããã°ãªããªãïŒæ¬è«æã§ã¯ïŒéä¿¡ä¿¡å·(å
ä¿¡å·)ãšéä¿¡ä¿¡å·ãå転ãããä¿¡å·(å転信å·) ã亀äºã« äŒéãïŒåä¿¡æ©ã§ãããã®ç»åãå ç®ããããšã§å
šç¹ç¯ç»åãçæãïŒãã®ç»åãçšããŠéä¿¡æ©ã§ããLEDã¢ã¬ã€ã远跡ããææ³ãææ¡ããïŒãã®ææ³ã§ã¯ïŒå ç®ç»åãå
šç¹ç¯ãšãªãããèŒåºŠå€ãäžæ§ã«ãªãïŒã¡ãã€ãã®è»œæžã«ãç¹ããïŒææ¡ææ³ã®æå¹æ§ã確èªããããã«ïŒèµ°è¡å®éšãè¡ã£ãïŒçµæãšããŠïŒåŸæ¥ããåªããBERç¹æ§ãšãªãããšã確èªãããïŒ
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- é»åæ
å ±éä¿¡åŠäŒè«æèª, vol.J95-B, no.2, pp.246-256
- 2012幎2æ
- http://hdl.handle.net/2237/23923
- 倪éœãšãã«ã®ãŒã®ååŸãè¡ãç¡ç·ã»ã³ãµãããã¯ãŒã¯ã«ãããããŒã¿äŒéæåçã®åäžãç®æããŠããïŒãããã¯ãŒã¯å
šäœã®æ¶è²»ãšãã«ã®ãŒãäœæžããæ¹æ³ãšããŠïŒããŒã¿éä¿¡æã«ããŒããããŒã¿ã®äžç¶ãè¡ãååäŒéæ¹åŒã®é©çšãèããïŒæ¬è«æã§ã¯ïŒãŸãããŒãã®é»æ± æ®éïŒæ¶è²»ãšãã«ã®ãŒãèæ
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é«éç§»åç°å¢äžã«ãããéªçŽäº€åšæ³¢æ°åå²ã®ã¬ãŠã¹ãã«ã¹åœ¢ç¶ã®æé©å
- äºè€å€§ä»ïŒå±±éæ¬ä¹ïŒã¢ã³ãŽã«ãã€ã«ãã¬ã
- é»åæ
å ±éä¿¡åŠäŒè«æèª, vol.J95-B, no.2, pp.317-325
- 2012幎2æ
- æ¬ç ç©¶ã§ã¯ïŒé«éç§»åç°å¢äžã§ã®æé-åšæ³¢æ°åæ£éä¿¡è·¯ã«ãããã·ã³ãã«éå¹²æž(ISI) ãšãã£ãªã¢éå¹²æž(ICI) ã®äœæžãç®çãšããŠïŒé«éäŒéæ¹åŒã®äžã€ã§ããéªçŽäº€åšæ³¢æ°åå²(BFDM) ã«çç®ããïŒæé-åšæ³¢æ°åæ£éä¿¡è·¯ã«ãããŠïŒå¹²æžã®äœæžã¯ä¿¡å·ã®ãã«ã¹åœ¢ç¶ã«äŸåããïŒBFDM ã¯ãã«ã¹èšèšã®èªç±æ§ãé«ãïŒæé-åšæ³¢æ°ã®å¶éæ§ã®é«ãã¬ãŠã¹ãã«ã¹ãçšããããšãã§ããããïŒå¹²æžäœæžã«æå¹ãªéä¿¡æ¹åŒãšèããããŠããïŒãããïŒéä¿¡è·¯ã«ãã£ãŠå¹²æžç¹æ§ãç°ãªãããïŒå¹²æžãæããããšãã§ããã¬ãŠã¹ãã«ã¹åœ¢ç¶ã®éžæãè¡ãå¿
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A Simple Cooperative Relaying with Alamouti Coded Transmission
- T. Yamaoka, Y. Hara, N. Fukui, H. Kubo, T. Yamazato
- IEICE Transactions on Communications, vol .E95-B, no. 2, pp.643-646
- 2012幎2æ
- Cooperative diversity using space-time codes offers effective space diversity with low complexity, but the scheme needs the space-time coding process in the relay nodes. We propose a simple cooperative relay scheme that uses space-time coding. In the scheme, the source node transmits the Alamouti coded signal sequences and the sink node receives the signal sequence via the two coordinated relay nodes. At the relay nodes, the operation procedure is just permutation and forwarding of the signal sequence. In the proposed scheme, none of the relay nodes need quadrature detection and space-time coding and the simple relay process offers effective space diversity. Moreover, simulations show the effectiveness of the proposed relay process by some simulations.
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éä¿¡ã®ãªã¢ã«ã¿ã€ã äŒé
- ç¬ å¶éä¹, çœæšåº·å»º, 山鿬ä¹, 岡ç°å, è€äºä¿åœ°, åéç¥å, èäºäŒžå€ªé
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, USN2011-89, pp.173-175, 鳥矜åžïŒæ¥æ¬ïŒ
- 2012幎1æ
- æ¬çš¿ã§ã¯ LEDä¿¡å·æ©ãšé«é床ã«ã¡ã©ãçšããè·¯è»éå¯èŠå
éä¿¡ã·ã¹ãã ãèããïŒLEDãé«éã«å€èª¿ãç¡ç·éä¿¡ãè¡ãããšãå¯èŠå
éä¿¡ãšããïŒãŸãè·¯è»ééä¿¡ãšã¯è»äž¡ãšéè·¯äžã®ã€ã³ãã©æ©åšãšã®éä¿¡ã®ããšã§ïŒå®å
šéè»¢æ¯æŽãç®çãšããŠããïŒéä¿¡æ©ã«LEDã¢ã¬ã€ïŒåä¿¡æ©ã«é«é床ã«ã¡ã©ãçšããå¯èŠå
éä¿¡ã·ã¹ãã ã«ã€ããŠã®ç ç©¶ã¯ïŒãããŸã§ã«å®éã«éä¿¡å®éšãè¡ãããŠããïŒãã®æå¹æ§ã瀺ãããŠããïŒãããïŒå®éšã«ãããŠåä¿¡æ
å ±ã®åŸ©å·ã¯ãªãã©ã€ã³ã§è¡ãããŠããïŒãªã¢ã«ã¿ã€ã éä¿¡ã¯å®çŸã§ããŠããªãã£ãïŒæ¬çš¿ã§ã¯ïŒãã®å¯èŠå
éä¿¡ã·ã¹ãã ã«ãããŠãªã¢ã«ã¿ã€ã 埩å·ãã§ããããã«éçºããåä¿¡æ©ã玹ä»ãã.
é«åºŠé路亀éã·ã¹ãã ã®ããã®å¯èŠå
éä¿¡ã«ãããéæ
å ±æºã®èª€èªèçæ¹å
- çœæšåº·å»ºïŒå±±éæ¬ä¹ïŒèäºäŒžå€ªéïŒåéç¥åïŒå²¡ç°åïŒè€äºä¿åœ°
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, USN2011-59, pp.13-18, 鳥矜
- 2012幎1æ
LED ã¢ã¬ãŒãšé«é床ã«ã¡ã©ãçšããå¯èŠå
éä¿¡ã®ç ç©¶éçº
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å ±éä¿¡ããã³ãã£ã¢ã»ãããŒ2011 ~ICT ç ç©¶éçºã®ææå±éã«åããŠ~, æç¥çç£æ¥åŽåã»ã³ã¿ãŒããŠã€ã³ã¯ããã¡ã12é 1201äŒè°å®€(è¬æŒã»çºè¡š)ã1208äŒè°å®€(å±ç€º)
- 2012幎1æ
- æ¬ç ç©¶éçºèª²é¡ã§ã¯ãé転è
ãèŠèŠçã«èªèããä¿¡å·æ©æ
å ±ã«å ããŠãLEDä¿¡å·æ©ããå®å
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éä¿¡ã«ããäŒéããããšã§ã亀差ç¹äºæ
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High-Speed LED Traffic Light Tracking Method Using Image/High-Speed Communication Hybrid Sensor
- K. Maeno, M. Tehrani, T. Fujii, H. Okada, T. Yamazato, M. Tanimoto, T. Yendo
- International Workshop on Advanced Image Technology (IWAIT), Ho Chi Minh City, Vietnam
- 2012幎1æ
Relay Selection Scheme Using Prediction of Harvested Energy for Solar-Powered Wireless Sensor Networks
- K. Ota, K. Kobayashi, T. Yamazato, M. Katayama
- International Symposium on EcoTopia Science (ISETS), p.106, Nagoya, Japan
- 2011幎12æ
- Solar-powered wireless sensor networks are attracting attention for outdoor long time operation such as environmental monitoring. Even if sensor nodes are charged by solar energy, nodes far from the BS (Base-Station) are stopped due to the lack of energy during nighttime. To prevent this problem, we consider the use of cooperative transmission. In cooperative transmission, energy consumption is balanced among the nodes because of the use of another node as a relay for data transmission of distant nodes. The conventional scheme to select a relay node is based on available battery energy and the expectation of energy consumption of each node. In this paper, we propose a relay selection scheme which is based on the prediction of harvested energy in addition to the available battery energy and the expected value of energy consumption. We evaluate the proposed scheme through packet delivery ratio and show its effectiveness.
é«éç§»åç°å¢äžã«ãããæé©ãªã¬ãŠã¹ãã«ã¹ãçšããéªçŽäº€åšæ³¢æ°åå²å€éãšWavelet Based OFDMãšã®å¹²æžç¹æ§æ¯èŒ
- äºè€å€§ä»ã山鿬ä¹ãã¢ã³ãŽã«ãã€ã«ãã¬ã
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, RCS2011-11, pp.91-95 , åå€å±
- 2011幎11æ
- æ¬ç ç©¶ã¯,é«éç§»åç°å¢äžã§ã®æé-åšæ³¢æ°åæ£éä¿¡è·¯ãããŠçããã·ã³ãã«éå¹²æž(ISI)ãšãã£ãªã¢éå¹²(ICI)ã®äœæžã«å¯ŸããŠæå¹ãšãããŠããéªçŽäº€åšæ³¢æ°åå²å€é(BFDM)ãš,Wavelet Based OFDMãšã®ç¹æ§æ¯èŒãè¡ã.ISI,ICIã¯ä¿¡å·ã®ãã«ã¹åœ¢ç¶ã«å€§ããäŸåãã.BFDM ã¯ãã«ã¹èšèšã®èªç±æ§ãé«ãããšãã,æé-åšæ³¢æ°å¶éæ§ã®é«ãã¬ãŠã¹ãã«ã¹ãçšããããšã§å¹²æžäœæžãè¡ãããšãã§ãã.ãŸã,Wavelet Based OFDMã¯ãŠã§ãŒãã¬ãããåºåºé¢æ°ãšããäŒéæ¹åŒã§ãã,å¹²æžäœæžã«æå¹ãšãããŠãã.æ¬ç ç©¶ã§ã¯,BFDMã®ã¬ãŠã¹ãã«ã¹ã®æé©åãéåä¿¡æ©ãã«ã¹ã®äžç¢ºå®æ§é¢æ°ã®æ¯ãæå€§åããããšã§è¡ã,Wavelet Based OFDMãšã®ç¹æ§æ¯èŒãè¡ã.
Teaching tips and Nagoya University OCW
- T. Yamazato
- Asia Regional OpenCourseWare Conference (AROCC) 2011, Meiji University, Tokyo, Japan
- 2011幎11æ
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å ±äŒé -LEDã¢ã¬ã€ãšé«é床ã«ã¡ã©ãçšããITSå¯èŠå
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- 山鿬ä¹
- å¿çšç§åŠåŠäŒç§æã·ã³ããžãŠã 2011ãäžçã«ã¯ã°ããäººãšæè¡ã, æžè°·ãã©ãã®å9Fç 修宀
- 2011幎10æ
- LEDä¿¡å·æ©ã«èŠç«ãŠãLEDã¢ã¬ã€ãé«éã«å€èª¿ãããããšã§ïŒ
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å ±äŒéãè¡ãããšã§ïŒãã©ã€ããŒãç®ã§èŠãŠç¢ºèªãã
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Robust Receiver Design for Road-to-Vehicle Communication System Using LED Array and High-Speed Camera
- Y. Shiraki, T. Nagura, T. Yamazato, S. Arai, T. Yendo, T. Fujii, H. Okada
- 18th World Congress on Intelligent Transport Systems , Orlando, Florida, USA
- 2011幎10æ
- In this paper, we focus attention on the visible light communication systems using an LED array as a transmitter and a high-speed camera as a receiver for road-to-vehicle communications in intelligent transport systems. Previously, we have proposed the hierarchical coding scheme which enables reception of high-priority data even if the receiver is far from the transmitter and have confirmed the effectiveness of the hierarchical coding scheme from results of primitive implementation experiments. However, there are many important works to develop the real-time communication system for an actual driving situation. In this paper, we discuss a robust receiver design in an actual driving situation. We introduce a series of image processing operations and demonstrate their effectiveness by field trials. As the results of the field trials, we have achieved 16kbps transmission and error-free communication up to communication distance of 70m using 16x16 LED array (transmitter) and high-speed camera (receiver) with the frame rate of 1000.
Overlay Coding for Road-to-Vehicle Visible Light Communication using LED Array and High-Speed Camera
- S. Nishimoto, T. Nagura, T. Yamazato, T. Yendo, T. Fujii, H. Okada, S. Arai
- International IEEE Conference on Intelligent Transportation Systems (ITSC), pp.1704-1709, Washington D.C., USA
- 2011幎10æ
- https://doi.org/10.1109/ITSC.2011.6082943
- This paper aims to improve the visible light communication system using LED array and high-speed camera by proposing what we call âoverlay codingâ. âOverlay codingâ is a new coding method to realize a hierarchical coding, through which a high-priority data can be received even if the receiver is far from a transmitter. Conventionally, the hierarchical coding has been realized through the wavelet transform that has a limitation of number and disposition of LEDs, and as a result it does not always match with the design of the transmitters (e.g. traffic lights, etc.) used in real life. To solve the limitation problem, we propose a more flexible way of designing the application of LEDs depending on the transmitters. In particular, overlay coding is realized through the procedures of coding and decoding. In coding, we replace one LED with a flexible number of LEDs, and the number depends on whether the data is high-priority or low-priority, then high-priority data and low-priority data are overlaid. In decoding, we first obtain the high-priority data, and then the low-priority data using retrieved high-priority data. The experimental result shows that the distance for receiving error-free data is extended from 30m to 70m in the overlay coding.
LED ã¢ã¬ãŒãšé«é床ã«ã¡ã©ãçšããå¯èŠå
éä¿¡ã®ç ç©¶éçº
- 山鿬ä¹
- ICT ã€ãããŒã·ã§ã³ãã©ãŒã©ã 2011, å¹åŒµã¡ãã» åœéäŒè°å Ž 1F äŒè°å®€(CEATEC JAPAN 2011 ãšåæéå¬)
- 2011幎10æ
- æ¬ç ç©¶éçºèª²é¡ã§ã¯ãé転è
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A Study on Cluster Lifetime of Single-hop Wireless Sensor Networks with Cooperative MISO Scheme
- Z. Huang, K. Kobayashi, M. Katayama, T. Yamazato
- IEICE Transactions on Communications, vol.E94-B, no.10, pp.2881-2885
- 2011幎10æ
- https://doi.org/10.1587/transcom.E94.B.2881
- This letter investigates the cluster lifetime of single-hop wireless sensor networks with cooperative Multi-Input Single-Output (MISO) scheme. The energy consumptions of both intra-cluster and out-cluster communications are considered. Moreover, uniform and linear data aggregations are discussed. It is found the optimal transmission scheme varies with the distance from the cluster to the base station. More interestingly and novelly, the effect of cluster size on the cluster lifetime has been clarified.
LEDã¢ã¬ã€ãšé«é床ã«ã¡ã©ãçšããå¯èŠå
éä¿¡ã«ããã誀ãèšæ£ç¬Šå·ã®ããã®éä¿¡è·¯å€ã®æšå®
- äžæŸ€æ
ä¹ä»ïŒå²¡ç°åïŒå±±éæ¬ä¹ïŒåéç¥åïŒè€äºä¿åœ°
- é»åæ
å ±éä¿¡åŠäŒ åºç€ã»å¢çãœãµã€ãšãã£å€§äŒ, A-17-6, p.210, æå¹
- 2011幎9æ
Cooperative Transmission Scheme with Inactive Node Reactivation Condition for Solar-Powered Wireless Sensor Networks
- K. Ota, K. Kobayashi, T. Yamazato, M. Katayama
- IEEE International Workshop on Wireless Distributed Networks (WDN), pp.2394-2398, Toronto, Canada
- 2011幎9æ
- https://doi.org/10.1109/PIMRC.2011.6139948
- Our goal is the improvement of the node activity rate in solar-powered wireless sensor networks. We consider the application of a cooperative transmission scheme that uses a relay node when a node sends data to reduce the consumption of energy of the entire network. However, if we do not consider the variations in energy harvesting, the node activity rate declines during nighttime. In this paper, we smooth out the day-and-night node activity rate variations by introducing the new inactive node reactivation condition and achieve the required high node activity rate.
åå€å±å€§åŠ OCW (åå€§ã®ææ¥)ã§å
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- 山鿬ä¹
- å¹³æ23å¹ŽåºŠå·¥åŠæè²ç ç©¶è¬æŒäŒè¬æŒè«æéïŒ9-217, åæµ·é倧åŠïŒæå¹
- 2011幎9æ
- æ æ¥ã«ã¯ïŒããããã®ã¡ãã»ãŒãžã蟌ããããŠããŸãïŒææ¥ãããå
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¬éãããŠãããŠããŒã¯ãªææ¥å®è·µ
- 山鿬ä¹
- å·¥åŠæè², Vol. 59ïŒNo. 4ïŒpp.4_105-4_107
- 2011幎8æ
- æ¬çš¿ã§ã¯ïŒåå€å±å€§åŠ OCW ïŒåå€§ã®ææ¥ïŒã§å
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å ±æºã®èªèææ³
- çœæšåº·å»ºïŒå±±éæ¬ä¹ïŒèäºäŒžå€ªéïŒåéç¥åïŒå²¡ç°åïŒè€äºä¿åœ°
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, USN2011-18, pp.73-78, çŠå²¡
- 2011幎7æ
- LEDãé«éç¹æ»
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å ±äŒéãè¡ãé«åºŠé路亀éã·ã¹ãã (ITS)ã®ããã®å¯èŠå
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å ±æºãåæã«èªèããç¶æ³ãæ³å®ããïŒè€æ°æ
å ±æºãåºå¥ããããã«ãããã¯ãããã³ã°ã«åºã¥ãé«éèªèææ³ãææ¡ãïŒèµ°è¡ç°å¢ãæš¡æ¬ãã鿢å®éšã«ããææ¡ææ³ã®æ§èœãè©äŸ¡ããïŒ
Visible Light Communication and Its Application to ITS
- T. Yamazato
- International Symposium on Emerging Short Range Communications, Room 1-312, FIT Building, Tsinghua University, China
- 2011幎6æ
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- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, RCS2011-06, pp221-226, æ²çž
- 2011幎6æ
- æ¬ç ç©¶ã§ã¯ïŒé«éç§»åç°å¢äžã§ã®æé-åšæ³¢æ°åæ£éä¿¡è·¯ã«ãããã·ã³ãã«éå¹²æž(ISI)ãšãã£ãªã¢éå¹²æž(ICI)ã®äœæžãç®çãšããŠïŒé«éäŒéæ¹åŒã®äžã€ã§ããéªçŽäº€åšæ³¢æ°åå²(BFDM)ã«çç®ããïŒæé-åšæ³¢æ°åæ£éä¿¡è·¯ã«ãããŠïŒå¹²æžã®äœæžã¯ä¿¡å·ã®ãã«ã¹åœ¢ç¶ã«äŸåããïŒBFDMã¯ãã«ã¹èšèšã®èªç±æ§ãé«ãïŒæé-åšæ³¢æ°ã®å¶éæ§ã®é«ãã¬ãŠã¹ãã«ã¹ãçšããããšãã§ããããïŒå¹²æžäœæžã«æå¹ãªéä¿¡æ¹åŒãšèããããŠããïŒãããïŒéä¿¡è·¯ã«ãã£ãŠå¹²æžç¹æ§ãç°ãªãããïŒå¹²æžãæããããšãã§ããã¬ãŠã¹ãã«ã¹åœ¢ç¶ã®éžæãè¡ãå¿
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å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, RCS2011-49, pp.85-90, çç倧åŠ
- 2011幎6æ
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Making Open Learning Come Alive: Takaya Yamazato of Nagoya University Talks About Engaging Students in OpenCourseWare
- T. Yamazato
- EDUCATION Inside
- 2011幎6æ
- Dr. Takaya Yamazato is a professor at Japan's Nagoya University, where he also heads the OpenCourseWare (OCW) team. The Education Insider caught up with him after the 2011 OCW Consortium conference to learn more about Nagoya's unique approach to putting course materials on the Web.
[Tutorial] Visible Light Communications
- T. Yamazato, S. Haruyama
- IEEE International Conference on Communications (ICC), Kyoto, Japan
- 2011幎6æ
- Visible light communications (VLC) is the latest optical wireless communications technologies that uses low-power light emitting diodes, or LEDs, not only to provide light but also to broadcast data. LEDs are extremely energy-efficient and predicted to become widespread in general lighting application. It is expected that LED market will reach $29 billion in 2017 that is comparable to today's NAND and DRAM markets [1]. Because LED is a solid-state lighting device, it can be modulated at high-speed compared with other lighting sources. VLC uses LEDs, which send data by flashing light at speeds undetectable to the human eye. The pioneer of VLC using LEDs is Professor Masao Nakagawa of Keio University. His first paper on this subject appeared in the early 2000, together with his successor Prof. Shinichiro Haruyama, the instructor of this tutorial. Later in 2003, he formed Visible Light Communication Consortium (VLCC). Now VLCC is lead by Prof. Haruyama. Please see the following video, an interview of Prof. Haruyama about VLC, which has been broadcast by NHK World in June 4, 2009. http://www.naka-lab.jp/movie/nhk_world.wmv So far various experimental VLC systems and prototypes are demonstrated. Such includes 4.8kbps visible light ID as an infrastructure to mobile-terminal application, independent sound transmission through RGB visible lights and 100Mbps VLC wireless LAN system. Using LED array, the data rate of 1 Gbps achieved by Keio University (Prof. Haruyama) that is the fastest at the moment [1]. In terms of longer range, there has been a demonstration by VLCC that achieved 1kbps transmission of the distance 2km, that is the world's longest distance for VLC. Samsung and ETRI are also active in developing VLC applications. They have demonstrated 120Mbps full duplex mobile-to-mobile transmission and 100Mbps signboard transmission. Please see the following video of Nakagawa lab. http://www.youtube.com/watch?v=QEh5f49LsB4 Widespread use of LEDs in traffic applications and growing interest in Intelligent Transport System (ITS) presents an opportunity for VLC. Data transmission using LED traffic lights, LED road illumination, and LED brake lights are typical application. Dr. Yamazato, the instructor of this tutorial, is a leader in VLC application to ITS and he recently achieved 16kbps data transmission and distance up to 70m in a driving situation with a vehicle moving with 30km/h. Today VLC using LED is a hot topic and VLC projects have been initiated in Europe and US. In 2006 Siemens launched VLC project. Later in 2008, European Commission established OMEGA project with a consortium of 20 European partners from industry and the scientific community [3]. Meanwhile, in 2008, the US National Science Foundation has approved a grant of $18.5 million to help establish and the Engineering Research Center focuses on VLC. The members of the Center include the Rensselaer Polytechnic Institute in New York, Boston University and the University of New Mexico. The University of California also have launched five-year research project called the Ubiquitous Communication by Light (UC-Light) that is founded with $3.5 million from the University. The project is anticipated to begin in 2009 and run for five years. VLC is in the process of standardization by the IEEE 802.15 TG7 and VLCC as well as other standard organizations. The first VLC specification standard was released from JEITA in conjunction with VLCC in 2007. Later in 2008, VLCC released their first specification standard adopting and expanding the IrDA physical layer. IrDA transceiver transmission wavelength (IrDA physical layer) is expanded to accommodate the visible light wavelength. By adapting this specification, the existing IrDA optical modules can be used for VLCC data transmission with slight modification. In January 2009, IEEE 802.15 (Wireless Personal Area Networks) Task Group 7 (Visible Light Communication) has been launched. At the 6th meeting held in November 2009 they adopted the baseline draft text for the development of the 802.15.7 standard. The goal of this tutorial is to introduce current VLC technology and its trends. Starting with an overview of VLC, participants will learn basics of VLC, on-going standardization activities and VLC. We will provide some experimental results and furthermore detail to enhance VLC application.
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- T. Yamazato
- OCWC-Global-2011, MIT, May 2011., MIT, Cambridge, MA, USA
- 2011幎5æ
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TDOA UWB Positioning with Three Receivers Using Known Indoor Features
- J. Kietlinski-Zaleski, T. Yamazato
- IEICE Transactions on Fundamentals, Vol.E94-A No.3 pp.964-971
- 2011幎3æ
- Ultra-Wideband is an attractive technology for short range positioning, especially indoors. However, for normal 3D Time Difference of Arrival (TDOA) positioning, at least four receivers with an unblocked direct path to the transmitter are required. A requirement that is not always met. In this work, a novel method for TDOA positioning using only three receivers is presented. TDOA positioning with three receivers is possible by exploiting the knowledge of some of the indoor features, namely positions of big flat reflective surfaces, for example ceiling and walls. The proposed method was verified using data from a measurement campaign.
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LED Traffic Light Detection Using High-speed-camera Image Processing for Visible Light Communication System,
- H. C. N. Premachandra, T. Yendo, M. P. Tehrani, T. Yamazato, H. Okada, T. Fujii, M. Tanimoto
- The Journal of the Institute of Television Engineers of Japan, vol.65, no.3, pp.354-360
- 2011幎2æ
- We propose a visible light road-to-vehicle communication system at intersection as an ITS (Intelligent Transport System) technique. In this system, the communication between a vehicle and an LED traffic light is conducted using an LED traffic light as a transmitter and an on-vehicle high-speed camera as a receiver. The LEDs in the transmitter emit light at high frequency, and those emitted light is captured by the high-speed camera for communications. Here, the luminance value of the LEDs in the transmitter should be found, and then it should be tracked in consecutive frames while the vehicle is moving by processing the images from the high-speed camera. In this paper, we propose new algorithms for finding and tracking the transmitter, which result in increased communication speed and data rate compared to the previous methods. Experiments using appropriate images showed the effectiveness of the proposals.
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- 2011幎1æ
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Erasure Coding for Road-to-Vehicle Visible Light Communication Systems
- H. Okada, T. Ishizaki, T. Yamazato, T. Yendo, T. Fujii
- IEEE Intelligent Vehicular Communications System Workshop, pp.970-974, Las Vegas, USA
- 2011幎1æ
- https://doi.org/10.1109/CCNC.2011.5766593
- In this paper, we focus on a road-to-vehicle visible light communication (VLC) system using LED traffic lights. In this system, an LED traffic light consists of a 2-dimensional LED array (2D LED array), and cars are equipped with high-speed 2-dimensional cameras (2D image sensors). An important issue of this system is frame loss. Sometimes, 2D image sensor in a car fails to get a frame. So as to mitigate the influence of frame loss, we propose to apply erasure coding to the road-to-vehicle VLC system. In the proposed system, a data sequence is encoded by LDPC code whose length is much longer than the size of 2D LED array. In addition, code synchronization is required for the proposed system. We also propose a code synchronization scheme, which makes use of error detection capability of LDPC code. We evaluate the performance of our proposed system, and show that it can recover frame loss for high SNR when less than 8 frames among total 18 frames are lost. In addition, we show that our proposed code synchronization scheme can ignore its errors.
Parallel Communication Using Visually Non-Lighting LEDs
- K. Maeno, T. Yendo, M. P. Tehrani, T. Fujii, H. Okada, T. Yamazato, M. Tanimoto
- International Workshop on Advanced Image Technology (IWAIT), Jakarta, Indonesia
- 2011幎1æ
- Previous studies on visible light communication uses visually lighting LEDs. However, LEDs are not always lighting. In this paper, we propose visible light communication method using visually non-lighting LEDs. This method enables us to communicate in different situations, e.g. using visually non-lighting tail lamps of cars or visually non-lighting traffic lights. We realize visually non-lighting LEDs by reducing luminescence energy of LEDs according to the brightness in the environment. To reduce luminescence energy of LEDs, we reduce the number of emitting LEDs, increase the interval of emitting, and decrease the luminance of emitting LEDs. In our research we consider the case that the transmitter is tail lamps of cars and the receiver is high-speed camera. We conduct two types of experiments to demonstrate the performance of the proposed system. One is to confirm that LEDs are visually non-lighting. The other is measurement of Bit Error Rate of communication using visually non-lighting LEDs. Experimental results demonstrate that it is possible to make communication using visually non-lighting LEDs. In our future work, we plan to use different sensor devices such as photo diode or CCD in order to decrease the error rate in communication.
Hierarchical Encoding System of Road-to-Vehicle Communication
- T. Masuda, T. Yendo, T. Yamazato, H. Okada, M. P. Tehrani, T. Fujii, M. Tanimoto
- International Workshop on Advanced Image Technology (IWAIT), Jakarta, Indonesia
- 2011幎1æ
- In this paper, we propose the new visible light road-to-vehicle communication system. We use the LED traffic light as the transmitter and the high-speed camera on the vehicle as the receiver. In this system, the data is encoded hierarchically and assign with the each frequency components of the image. We use the DFT for hierarchical encoding considering channel characteristic and quantization of the luminance. The communication experiments were conducted to confirm the effectiveness of the proposed method.
Image Processing Based Road-to-vehicle Visible Light Communication
- H. C. N. Premachandra, T. Yendo, M. P. Tehrani, T. Yamasato, H. Okada, T. Fujii, M. Tanimoto
- International Workshop on Advanced Image Technology (IWAIT), Jakarta, Indonesia
- 2011幎1æ
- Visible Light Communication(VLC) has been introduced as a new wireless communication method. In this paper, we propose a VLC system for Intelligent Transport System (ITS) to communicate between infrastructure and the vehicle. In this system, we use a LED array as a transmitter and on-vehicle high speed camera as a receiver. Here, LEDs in the transmitter emit light in 500Hz and the emission patterns are used to achieve communication, by capturing them using the high speed camera in high frame rate. The images captured by high speed camera are processed to find the transmitter, track the found transmitter, and capture the emission pattern of transmitter in consecutive frames. In our previous work, we proposed algorithms to finding and tracking. In this paper, we introduce method to capture the emission pattern of the transmitter. Then out door communication experiments were conducted to confirm the effectiveness of the proposed VLC system.
Dynamic Bandwidth Allocation of Satellite/Terrestrial Integrated Mobile Communication System
- T. Yamazato, T. Aman, M. Katayama
- IEEE Global Communications Conference (GLOBECOM), FLORIDA, U.S.A
- 2010幎12æ
- In this paper, we propose two dynamic bandwidth allocation (DBA) schemes, a game theory based DBA and a successive DBA, for satellite/terrestrial integrated mobile communication system (STICS). The game theory based DBA allocate the bandwidth according to a utility function based on a weighted demand bandwidth of both satellite and terrestrial system. The successive DBA recursively allocates an unit of bandwidth according to a weighted number of bandwidth unfilled cells of both satellite and terrestrial systems, until the total bandwidth is fulfilled. As results, both DBA outperform the conventional fixed bandwidth allocation scheme. Between two proposed DBA, the successive DBA shows better spectral improvement ratio than the game theory based DBA.
LED Traffic Light Detection Using High-speed-camera Image Processing for Visible Light Communication System,
- H. C. N. Premachandra, T. Yendo, M. P. Tehrani, T. Yamazato, H. Okada, T. Fujii, M. Tanimoto
- Workshop on Picture Coding and Image Processing, PCSJ2010/IMPS2010, Nagoya, Japan
- 2010幎12æ
- Intelligent transport system has been introduced to reduce traffic problems such traffic accidents and traffic congestions. In this paper, we introduce a receiver for a road to vehicle Visible Light Communication (VLC) system which is proposed as an Intelligent Transport System (ITS) technique. In this system, an on-vehicle high-speed camera is used as a receiver and an LED array is used as a transmitter. VLC is a wireless communication using luminance. Here, transmitter send information by emitting light and receiver receive them by capturing the luminance of emitting LEDs in the array(Luminance: whether each LED is on or off). For capturing the Luminance, it is necessary to find the transmitter and track it in consecutive frames. In our previous works we introduced methods for finding and tracking. In this paper, we shortly explain the proposed transmitter finding and tracking methods and then a new method is proposed for capturing the luminance of LEDs to achieve communication.
Hierarchical Encoding System for Road-to-Vehicle Communication Using LED Traffic Light
- T. Masuda, T. Yendo, T. Yamazato, H. Okada, M. P. Tehrani, T. Fujii, M. Tanimoto
- Workshop on Picture Coding and Image Processing, PCSJ2010/IMPS2010, Nagoya, Japan
- 2010幎12æ
- This paper discusses the visible light road-to-vehicle communication system at intersection as one of ITS (Intelligent Transport System) technique. The communication between a vehicle and an LED traffic light is approached using an LED traffic light as a transmitter, and on-vehicle high-speed camera as a receiver. In this system, it is able to send data by blinking the LEDs of the traffic light in two dimensional patterns, and able to receive them by high-speed camera with image processing. Here, we aim to conduct long-distance high-speed visible light communication. When the distance between transmitter and receiver is far, the image of the LED traffic light captured by on-vehicle high-speed camera is very small. So, if the data are put on two dimension patterns without modification, data would be mistaken, because the two dimension patterns canât be realized correctly. To solve this problem, data are encoded hierarchically before they are lighted by the LED traffic light. This is called as hierarchical encoding that the data are assigned with each spatial frequency.
Parallel Visible Light Communication Using Visually Non-Lighting LEDs
- K. Maeno, T. Yendo, M. P. Tehrani, T. Fujii, T. Yamazato, H. Okada, M. Tanimoto
- Workshop on Picture Coding and Image Processing, PCSJ2010/IMPS2010, Nagoya, Japan
- 2010幎12æ
- The proposed visible light communication method uses visually non-lighting LEDs, which enables us to communicate in different situations, e.g. using visually non- lighting tail lamps of cars or visually non-lighting traffic lights. We realize visually non-lighting LEDs by reducing luminescence energy of LEDs according to the brightness in the environment. Experimental results demonstrate that it is possible to make communication using visually non-lighting LEDs.
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- 2010幎12æ
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EXIT Analysis for MAP-based Joint Iterative Decoding of Separately Encoded Correlated Sources
- K. Kobayashi, T. Yamazato, M. Katayama
- IEICE Transactions on Communications, vol.E93-B, no.12, pp.3509-3513
- 2010幎12æ
- https://doi.org/10.1587/transcom.E93.B.3509
- We develop a mathematical framework for the extrinsic information transfer (EXIT) analysis to assess the convergence behavior of maximum a posteriori (MAP)-based joint iterative decoding of correlated sources, which are separately encoded and transmitted over noisy channels. Unlike the previous work, side information about the correlation is not perfectly given at the joint decoder but is extracted from decoder output and updated in an iterative manner. The presented framework provides a convenient way to compare between schemes. We show that it allows us to easily and accurately predict joint decoding gain and turbo cliff position.
TOA UWB Positioning with Two Receivers Using Known Indoor Features
- J. Kietlinski-Zaleski, T. Yamazato, M. Katayama
- IEICE Transactions on Communications, vol.E93-B, no.12, pp.3624-3631
- 2010幎12æ
- Ultra-Wideband is an attractive technology for short range positioning, especially indoors. However, for normal Time of Arrival (ToA) positioning, at least three receivers with unblocked direct path to the transmitter are required. A requirement that is not always met. In this work, a novel algorithm for ToA positioning using only two receivers is presented. This is possible by exploiting the knowledge of some of the indoor features, namely positions of big flat reflective surfaces, for example ceiling and walls. The proposed algorithm was tested using data from a measurement campaign.
Experimental Results on Simple Distributed Cooperative Transmission Scheme with Visible Light Communication
- T. Yamazato, K. Nakao, H. Okada, M. Katayama
- IEICE Transactions on Communications, vol.E93-B, no.11, pp.2959-2962
- 2010幎11æ
- We consider a distributed transmission of data packet to a sink where the distance of a sensor node to a sink is much longer than the maximum communication range of each sensor node. We give a simple modification to the transmitter, i.e., multiplication of random phase before the transmission. Thanks to Turbo Code, it is possible to extend the trans- mission range as the received amplitude varies symbol by symbol for our scheme while whole data packet may be lost for the conventional scheme. In this letter, we report the experimental results of our scheme equivalently developed using visible light communication.
Performance evaluation of the cognitive piggyback overlay systems with dirty paper coding
- J. Naganawa, K. Kobayashi, M. Katayama, T. Yamazato
- International Symposium on Communications and Information Technologies (ISCIT), no. FA1-1-4, pp.974-979, Tokyo, Japan
- 2010幎10æ
- https://doi.org/10.1109/ISCIT.20https://doi.org/10.5665130
- This manuscript considers a secondary system sharing the spectrum with the primary system at the same time and on the same frequency. We propose a cognitive overlay system in which the secondary system relays the primary signal and piggybacks its own data on it. Furthermore, the secondary system uses the channel coding based on the dirty paper coding (DPC). The result of the analysis shows that the proposed scheme allows the secondary system to communicate at the same speed as the primary system without any harm to it.
Improvement of Sequential-Test-Based Cooperative Spectrum Sensing Systems in Band Limited Control Channels
- S. Mitsuya, K. Kobayashi, T. Yamazato, M. Katayama
- International Symposium on Communications and Information Technologies (ISCIT), no. FA1-1-3, pp.968-973, Tokyo, Japan
- 2010幎10æ
- https://doi.org/10.1109/ISCIT.20https://doi.org/10.5665127
- In a cooperative spectrum sensing system, many nodes perform spectrum sensing and report their decisions to one fusion center via control channels. This paper considers efficient use of the frequency band for the control channels. For this purpose, sequential-test is introduced for the local decision at each node. With this scheme, the transmission timing of the reports from the nodes becomes at random and necessary maximum bandwidth for the control channels decreases. Numerical results show that this sequential-test-base-scheme not only decreases the number of simultaneous reports but also improves sensing reliability. For further improvement, this paper also introduces a decision scheme at the fusion center based on probabilistic features of the reports from the nodes.
Inband and Outband Spectrum Analysis of the BFDM and BFDM/OQAM Signals with Truncated Gaussian Pulses
- B. Mongol, T. Yamazato, M. Katayama
- International Symposium on Information Theory and Its Applications (ISITA), Taichung, Taiwan
- 2010幎10æ
- Pulse-shaping OFDM, or more generally BFDM and BFDM/OQAM, systems are originally proposed to combat inter- carrier interference (ICI) caused by time-variance of the channel. The main property that makes these signals robust against ICI is that they allow to employ time-frequency well localized pulses, particularly Gaussian pulse which has the best time-frequency localization. However, this property also suppresses the outband or inband spectral leakage of the BFDM and BFDM/OQAM signal, making them attractive physical layer modulation scheme for cognitive radio. In this paper we analyze the power density spectra of the BFDM and BFDM/OQAM signals and numerically evaluate the inband and outband spectra for truncated Gaussian pulses.
Error-correcting scheme based on chaotic dynamics and its performance for noncoherent chaos communications
- S. Arai, Y. Nishio and T. Yamazato
- NOLTA, IEICE, vol. 1, no. 1, pp. 196-206, Oct. 2010.
- 2010幎10æ
- This paper proposes a novel error-correcting scheme using chaotic dynamics for noncoherent chaos communications. In our proposed system, two successive chaotic sequences are generated from the same chaotic map; the second sequence is generated with an initial value which is the last value of the first sequence. In this case, successive chaotic sequences having the same chaotic dynamics are created. This feature gives the receiver additional information to correctly recover the information data and thus improves the bit error performance of the receiver. As results of the computer simulation, we confirm that the advantage gained in BER performance of the proposed error-correcting method is about 1-1.5 dB compared to conventional method. In addition, we achieve that the proposed error-correcting scheme is performed without the new additional redundancy code by using the chaotic dynamics.
æéåšæ³¢æ°åæ£éä¿¡è·¯ã«ãããBFDM/OQAMã®ããã®ã«ã«ãã³éä¿¡è·¯æšå®åš
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- é»åæ
å ±éä¿¡åŠäŒè«æèª, vol.J93-B, no.10, pp.1466-1480
- 2010幎10æ
- éªçŽäº€åšæ³¢æ°åå²å€é/ãªãã»ãã QAM (BFDM/OQAM) ã¯ã¬ãŠã¹ãã«ã¹ãæ¡çšããããšãã§ããã ã,ã¬ãŒãã€ã³ã¿ãŒãã«ãçšããªããŠã笊å·éå¹²æž (ISI) ãšãã£ãªã¢éå¹²æž (ICI) ãæå§ã§ãã.ããã,端æ«ã é«éç§»åããŠããæéåšæ³¢æ°åæ£éä¿¡è·¯ã§ã¯éä¿¡è·¯ã®ç¶æ
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æ¹åŒãšæž¬å®æ¹çšåŒã®å°åºã«ã€ããŠè¿°ã¹ãŠãã. BFDM/OQAM ã®éåä¿¡æ©ã¢ãã«ã¯,ãªãã»ãããè¡ããªã BFDM, ãã«ã¹ã·ã§ãŒãã³ã° OFDM,ãããŠåŸæ¥ã® OFDM ãå
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A Study on Joint Channel Decoding Using Spatial Correlation of Sensor Observations According to ADC Bit levels
- K. Kobayashi, T. Yamazato, M. Katayama
- IEEE International Workshop on Wireless Distributed Networks (WDN), pp.484-489, Istanbul, Turkey
- 2010幎9æ
- https://doi.org/10.1109/PIMRCW.20https://doi.org/10.5670522
- In densely deployed wireless sensor networks, observations of the sensor nodes are spatially correlated. In this paper, we study a joint channel decoding scheme utilizing bit correlation of the sensor observations according to bit levels of analog-digital converter (ADC). If sensor ADC output is interpreted as natural binary numeral, carry propagation may occur between adjacent ADC output values. Such carry propagation leads to the degradation of joint decoding gain. We focus on the use of Gray code for avoiding the carry propagation. The performance of our approach is demonstrated by simulations using sensor data from experiments in a real indoor environment.
TDOA UWB Positioning with Three Receivers Using Known Indoor Features
- J. Kietlinski-Zaleski, T. Yamazato, M. Katayama
- IEEE International Conference on Ultra-Wideband (ICUWB), Nanjing. China
- 2010幎9æ
- https://doi.org/10.1109/ICUWB.20https://doi.org/10.5616909
- Ultra-Wideband is an attractive technology for short range positioning, especially indoors. However, for normal 3D Time Difference of Arrival (TDoA) positioning, at least four receivers with unblocked direct path to the transmitter are required. A requirement that is not always met. In this work, a novel method for TDoA positioning using only three receivers is presented and tested using real-world measurements. Positioning with three receivers is possible by exploiting the knowledge of some of the indoor features, namely positions of big flat reflective surfaces, reflectors, for example ceiling and walls.
Tracking an LED Array Transmitter for Visible Light Communications in the Driving Situation
- T. Nagura, T. Yamazato, M. Katayama, T. Yendo, T. Fujii, H. Okada
- IEEE International Symposium on Wireless Communication Systems (ISWCS), pp.765-769, York, United Kingdom
- 2010幎9æ
- https://doi.org/10.1109/ISWCS.20https://doi.org/10.5624361
- In this paper, we discuss on a decoding algorithm for visible light communication systems in the driving situation using an LED array transmitter and a high-speed camera receiver. We propose an LED array detection method using M-sequence and an LED array tracking method using inverted signals. We confirm that we can distinguish LED array candidates correctly with M-sequence. We also confirm that we can suppress the flicker of the LED and improve the data rate as compared with the previous method.
UWB Positioning Using Known Indoor Features - Environment Comparison
- J. Kietlinski-Zaleski, T. Yamazato
- International Conference on Indoor Positioning and Indoor Navigation (IPIN), Zurich, Switzerland
- 2010幎9æ
- https://doi.org/10.1109/IPIN.20https://doi.org/10.5648089
- Ultra-Wideband is an attractive technology for short range positioning, especially indoors. However, for normal Time of Arrival (TOA) positioning, at least three receivers with unblocked direct path to the transmitter are required. A requirement that is not always met. In our previous work \\\\cite{Kietlinski-Zaleski2010PLANS} we presented a novel 3D TOA UWB indoor positioning method that uses only two receivers. This is possible by exploiting the knowledge of some of the indoor features, namely ceiling and walls. In this work, we verify the usability of the method using measurement results in three environments: a lecture room, a cluttered laboratory and a corridor. By comparing the results of the method for three environments, we draw conclusions about its strengths and weaknesses.
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- 2010幎9æ
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- 2010幎9æ
LED Traffic Light Detection Using a High-speed-camera for a Road-to-vehicle Visible Light Communication System
- H. C. N. Premachandra, T. Yendo, M. P. Tehrani, T. Yamazato, H. Okada, T. Fujii, M. Tanimoto
- Forum on Informatio Technology, RM-002, Fukuoka
- 2010 幎9æ
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- é«åºŠé路亀éã·ã¹ãã (ITS)ã®åéã«ãããŠ,LEDãçšããè·¯è»éã»è»ã
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å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.110, no.153, SR2010-31, pp.89-94, ATR(京éœ)
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- å調ã¹ãã¯ãã«ã»ã³ã·ã³ã°ã·ã¹ãã ã§ã¯ïŒè€æ°ã®ããŒããã¹ãã¯ãã«ã»ã³ã·ã³ã°ãåæã«è¡ãïŒå€å®çµæãã³ã³ãããŒã«ãã£ãã«ãéããŠãã¥ãŒãžã§ã³ã»ã³ã¿ãŒã«å ±åããïŒ æ¬çš¿ã§ã¯ïŒãã®ã³ã³ãããŒã«ãã£ãã«ã®åšæ³¢æ°åž¯åå¹
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ã®æå¹å©çšã®ããïŒåããŒãã«ãããå€å®æ¡ä»¶ã«é次æ€å®ãé©çšããïŒ éæ¬¡æ€å®ã«ããïŒããŒãããã®å ±åã®ã¿ã€ãã³ã°ããããããïŒåæå ±åæ°ã®æå€§å€ãæžãïŒã³ã³ãããŒã«ãã£ãã«ã«å¿
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ãåæžããããšãã§ããïŒ ãŸã鿬¡æ€å®ã¯ïŒåæå ±åæ°ãæžããã ãã§ã¯ãªãïŒäžæ¬¡ã·ã¹ãã ä¿¡å·ã®æ€åºç²ŸåºŠãæ¹åã§ããããšãïŒæ°å€äŸã«ãã瀺ãïŒããã«ïŒå ±åæ°ã®åããèæ
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Visible Light Communication Between LED Array and On-vehicle High Speed Camera
- H. C. N. Premachandra, T. Yendo, M. P. Tehrani, T. Yamazato, H. Okada, T. Fujii, M. Tanimoto
- Technical Report of IEICE, ITS2010-10, pp.25-30
- 2010幎7æ
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ã®LEDãçšãã䞊åå¯èŠå
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- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, ITS2010-9, pp.19-24
- 2010幎7æ
LEDã¢ã¬ãŒãšã€ã¡ãŒãžã»ã³ãµãçšããå¯èŠå
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- 山鿬ä¹
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å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, Vol. SAT2010-27, pp.97-102, åèŠå·¥æ¥å€§åŠ
- 2010幎7æ
- è¡æç§»åéä¿¡ã·ã¹ãã åã³å°äžç§»åéä¿¡ã·ã¹ãã ã®çžäºè£å®ã®ããè¡æå°äžçµ±åç§»åéä¿¡ã·ã¹ãã ãæ³šç® ãããŠãã.åã·ã¹ãã ã§ã¯åäžæºåž¯ç«¯æ«ã§è¡æç§»åé ä¿¡ã·ã¹ãã ãšå°äžç§»åéä¿¡ã·ã¹ãã ãå©çšããããšãã§ãã ã®ã§ãã€ã§ãã©ãã§ãå®å®ããéä¿¡ãæäŸå¯èœã§ãã.ãŸãåšæ³¢æ°åž¯åã®æå¹å©çšã®ããè¡æç§»åéä¿¡ã·ã¹ãã åã³ å°äžç§»åéä¿¡ã·ã¹ãã ã§åäžåšæ³¢æ°ãå
±çšãã.ãããè¡æç§»åéä¿¡ã·ã¹ãã åã³å°äžç§»åéä¿¡ã·ã¹ãã ã§ã¯ãã©ãã ã¯ãç°ãªã,å€ãã®åŒæãçºçãããšèãããã.åŒæã®çºçã«ãã£ãŠé«ãåšæ³¢æ°å©çšå¹çã®éæãå°é£ã§ãã.ã ãã§æ¬çš¿ã§ã¯è¡æç§»åéä¿¡ã·ã¹ãã åã³å°äžç§»åéä¿¡ã·ã¹ãã ã§ã¯ãã©ããã¯ã«å¿ããŠåçã«åž¯åãå²ãåœãŠãåç 垯åå¹
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- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, Vol. ITS2010-12, pp. 31-36, è²é¡
- 2010幎7æ
- æ¬çš¿ã§ã¯LED ä¿¡å·æ©ãšè»èŒé«é床ã«ã¡ã©ãçšããè·¯è»éå¯èŠå
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High-speed-camera Image Processing Based LED Traffic Light Detection for Road-to-vehicle Visible Light Communication
- H.C.N. Premachandra, T. Yendo, M. P. Tehrani, T. Yamazato, H. Okada, T. Fujii, M. Tanimoto
- IEEE Intelligent Vehicles Symposium (IV), pp.793-798, San Diego, California, USA
- 2010幎6æ
- https://doi.org/10.1109/IVS.20https://doi.org/10.5548097
- As one of ITS technique, a new visible light road to- vehicle communication system at intersections is proposed. In this system, the communication between a vehicle and an LED traffic light is conducted using an LED traffic light as a transmitter, and an on-vehicle high-speed camera as a receiver. The LEDs in the transmitter emit light in high frequency and those emitting LEDs are captured by the high-speed camera for making communication. Here, the luminance value of LEDs in the transmitter should be captured in consecutive frames to achieve effective communication. For this purpose, first the transmitter should be found, then it should be tracked in consecutive frames by processing the images from the high-speed camera. In this paper, we propose new effective algorithms for finding and tracking the transmitter, which result in a increased communication speed, compared to the previous methods. Experiments using appropriate images showed the effectiveness of the proposals.
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å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, Vol.110 No.72 (WBS2010-12) pp.63-68, æ²çž
- 2010幎6æ
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å ±ä¿¡å·ããã¹ã¿ãéä¿¡ããæ¹åŒãææ¡ãã. ãã®ä¿¡å·ã¯,äœãé»åã¹ãã¯ãã«å¯åºŠãšé«ãæéåè§£èœãå
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å ±ä¿¡å·ãšéç³ãã圢ã§, åäœå¶åŸ¡ã®ããã®å¶åŸ¡ä¿¡å·ãçŽäº€åšæ³¢æ°åå²å€éå€èª¿(OFDM)ãçšããŠéåä¿¡ãããã®ãšãã. æ¬çš¿ã§ã¯, ãã®ææ¡æ¹åŒãå®éã®ã·ã¹ãã ãšããŠæ§ç¯ããããã®æ°å€äŸã瀺ã.ããã«, æ§èœè©äŸ¡ãè¡ããã, éç³ãã2ã€ã®ä¿¡å·ãäºãã®ä¿¡å·ã«äžãã圱é¿ãæ°å€äŸã«ãã瀺ã.
å調åäœã®ããã®ç¡ç·å¶åŸ¡æ¹åŒã«ãããäŒé誀ãã®åœ±é¿ãšç¹æ§æ¹åææ³
- è¿è€ç¶æ¬, 山鿬ä¹, çå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.WBS2010-11, pp.57-62, æ²çž
- 2010幎6æ
- æ¬çš¿ã§ã¯ïŒç¡ç·å¶åŸ¡ã«ãã£ãŠè€æ°æ©åšãå調ããŠåäœãããã·ã¹ãã ã«ãããŠïŒç¡ç·éä¿¡è·¯ã«ãããäŒé誀ããïŒæ©åšã®å調åäœã« äžãã圱é¿ãæããã«ããïŒããã«ïŒäŒé誀ããååšããç¡ç·å¶åŸ¡ã«ãããŠãå調åäœã®åè³ªãæ¹åããææ³ãææ¡ããïŒå¶åŸ¡å¯Ÿè±¡ã¯å転ååç«æ¯åãçšãïŒå¶åŸ¡å
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å ±ã®ãã£ãŒãããã¯ãç¡ç·éä¿¡ã«ãã£ãŠè¡ãïŒå調åäœããç°¡åãªèšå®ãšããŠïŒãã®å転ååç«æ¯åã2å°çšããŠäºãã«é¡ååäœãè¡ãïŒãã®ãããªã·ã¹ãã ã«ãããŠïŒããããã®å¶åŸ¡å¯Ÿè±¡ãèªåå®ãšä»æ¹å®ã®äž¡æ¹ã®å¶åŸ¡ä¿¡å·ãåä¿¡ãïŒãŸãã¡ã€ã³ã³ã³ãããŒã©ã§ã¯ïŒåæ¹ã®å¶åŸ¡å¯Ÿè±¡ã®ç¶æ
æ
å ±ã«åºã¥ããŠïŒå¶åŸ¡ä¿¡å·ãçæããæ¹æ³ãææ¡ããïŒãããŠïŒå¶åŸ¡ç³»ãç¬ç«ã«ããããã®ä¿¡å·ãéåä¿¡ããå Žåãšæ¯èŒããŠïŒå調åäœã®åæç¹æ§ãæ¹åããããšã瀺ãïŒ
倪éœãšãã«ã®ãŒã®ååŸãè¡ãç¡ç·ã»ã³ãµãããã¯ãŒã¯ã«ãããå調ARQãããã³ã«ãçšãããããã¯ãŒã¯çšŒåæéã®å»¶é·
- 倪ç°å¥å€ªéïŒå°æå¥å€ªéïŒå±±éæ¬ä¹ïŒçå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.110, no.50, USN2010-1, pp.1-4, , æ±äº¬
- 2010幎5æ
- ç¡ç·ã»ã³ãµãããã¯ãŒã¯ã§ã¯ã»ã³ãµããŒãã®é·æçšŒåãšé«ä¿¡é ŒãªããŒã¿äŒéãæ±ããããïŒããã§ã»ã³ãµããŒãã®é·æçšŒåæ¹æ³ãšããŠå€ªéœãšãã«ã®ãŒã®ååŸãèããïŒãŸãïŒé«ä¿¡é ŒãªããŒã¿äŒéæ¹æ³ãšããŠå調ARQ(èªååéèŠæ±) ãããã³ã«ã«æ³šç®ããïŒæ¬çš¿ã§ã¯ã»ã³ãµããŒãã倪éœãšãã«ã®ãŒã®ååŸãè¡ãç°å¢äžã§å調ARQ ãããã³ã«ã®é©çšãèããïŒãããã¯ãŒã¯çšŒåæéã§è©äŸ¡ããããšã§å調ARQãããã³ã«ããããã¯ãŒã¯çšŒåæéã®å»¶é·ã«æå¹ã§ããããšã瀺ãïŒ
奚å±è¬æŒïŒœèŠ³æž¬ããŒã¿éã®ADCãããã¬ãã«ããšã®çžé¢ãå©çšããçµ±ååŸ©å·æ³ - ADCåºåã®æ¡äžãåé¿ã«ããæ§èœæ¹å广ã®è©äŸ¡ -
- å°æå¥å€ªéïŒå±±éæ¬ä¹ïŒçå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.MoMuC2010-5, pp.69-74, æ²çž
- 2010幎5æ
- ç¡ç·ã»ã³ãµãããã¯ãŒã¯ã§ã¯ é«ã芳枬粟床ãåŸãããã«è€æ°ã®ã»ã³ãµããŒããå¯ã«é
眮ããããšãå€ãïŒåããŒãã®èŠ³æž¬ããŒã¿ã¯äºãã«çžé¢ãæããŠããïŒæ¬çš¿ã§ã¯ïŒã»ã³ãµã®ADCåºåã®åãããã¬ãã«ã«å¿ããŠèŠ³æž¬ããŒã¿éã®çžé¢ãå©çšãã誀ãèšæ£åŸ©å·æ³ã«ã€ããŠæ€èšããïŒç¹ã«ïŒã»ã³ãµã®ADCåºåã«çããæ¡äžãã®åœ±é¿ã«çç®ãïŒã°ã¬ã€ç¬Šå·ãçšããŠæ¡äžããåé¿ããããšã§èª€ãèšæ£åŸ©å·ã®æ§èœåäžãå³ãïŒå±å
ç°å¢ã®å®æž¬ããŒã¿ã埩å·ã·ãã¥ã¬ãŒã·ã§ã³ã§å©çšãïŒADCåºåã®æ¡äžãåé¿ã«ããåŸ©å·æ§èœåäžã®å¹æãè©äŸ¡ããïŒ
Improved Decoding Methods of Visible Light Communication System for ITS using LED Array and High-Speed Camera
- T. Nagura, T. Yamazato, M. Katayama, T. Yendo, T. Fujii, H. Okada
- IEEE Vehicular Technology Conference (VTC-Spring), Taipei, Taiwan
- 2010幎5æ
- https://doi.org/10.1109/VETECS.20https://doi.org/10.5493958
- In this paper, we consider visible light communication systems using LED array as a transmitter and high-speed camera as a receiver for Intelligent Transport System (ITS). Previously, we have proposed the hierarchical coding scheme which allocates data to spatial frequency components of the image depending on the priority. This scheme is possible to receive information of the high-priority even if communication distance is long. However, we need to distinguish multi-valued data from the received image by using a hierarchical coding. In this paper, we propose two improved decoding methods, and demonstrate to distinguish multi-valued data more correctly in the experiment.
Optimal Cluster Partitioning for Wireless Sensor Networks with Cooperative MISO Scheme
- Z. Huang, T. Yamazato, M. Katayama
- Advanced International Conference on Telecommunications (AICT), pp.323-328, Barcelona, Spain
- 2010幎5æ
- https://doi.org/10.1109/AICT.20https://doi.org/10.6714500
- The paper discusses the optimal cluster partitioning for wireless sensor networks deployed in continuous areas. Both single-hop and multi-hop transmissions with cooperative Multi-Input Single-Output (MISO) scheme are considered for inter-cluster communications. The effects of cluster size in the energy consumption of intra-cluster communication and the amount of fused data are included in calculation. As a result, the dominant factors of the maximal network lifetimes are listed as: the cluster farthest from base station in single-hop transmission and the closest cluster in multi-hop transmission. In addition, the maximal network lifetimes of single-hop and multi-hop transmissions are compared and it is found that there exists a threshold of network size that determines which transmission is the better candidate.
Experimental Validation of TOA UWB Positioning with Two Receivers Using Known Indoor Features
- J. Kietlinski-Zaleski, T. Yamazato, M. Katayama
- IEEE/ION Position Location and Navigation Symposium (PLANS), Palm Springs, California, USA
- 2010幎5æ
- https://doi.org/10.1109/PLANS.20https://doi.org/10.5507253
- Ultra-Wideband is an attractive technology for short range positioning, especially indoors. However, for normal Time of Arrival (ToA) positioning, at least three receivers with unblocked direct path to the transmitter are required. This requirement is not always met. In this work, a novel algorithm for ToA positioning using only two receivers is presented and validated using data from a measurement campaign. Positioning with two receivers is possible by exploiting the knowledge of some of the indoor features, namely positions of big flat reflective surfaces, for example ceiling and walls.
Performance Evaluation of Error-Correcting Scheme Without Redundancy Code for Noncoherent Chaos Communications
- S. Arai, Y. Nishio, T. Yamazato, S. Ozawa
- IEEE International Symposium on Circuits and Systems (ISCAS), Paris, France
- 2010幎5æ
- https://doi.org/10.1109/ISCAS.20https://doi.org/10.5537140
- This paper considers a novel error-correcting scheme exploiting chaotic dynamics for noncoherent chaos communication. In our proposed system, two successive chaotic sequences are generated from the same chaotic map; the second sequence is generated with an initial value which is the last value of the first sequence. In this case, successive chaotic sequences having the same chaotic dynamics are created. This feature gives the receiver additional information to correctly recover the information data and thus improves the bit error performance of the receiver. Further, enhanced efficiency also comes from operating on successively modulated data; by involving less redundancy in the error correction system, it can be designed with high coding rate. In this paper, we analyze the schemeâs capability, by examining computational times and accuracy rates of error correction. bounds on its capability.
芳枬ããŒã¿éã®çžé¢ãå©çšããçµ±ååŸ©å·æ³ãžã®ADCãããã¬ãã«ã«å¿ããçžé¢æšå®ã®é©çš
- å°æå¥å€ªéïŒå±±éæ¬ä¹ïŒçå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒè«æèª, vol.J93-A, no.5, pp.353-364
- 2010幎5æ
- ç¡ç·ã»ã³ãµãããã¯ãŒã¯ã§ã¯é«ã芳枬粟床ãåŸãããã«å€æ°ã®ã»ã³ãµããŒããå¯ã«é
眮ããããšãå€ãïŒåããŒãã®èŠ³æž¬ããŒã¿ã¯äºãã«çžé¢ãæããïŒæ¬è«æã§ã¯ïŒã»ã³ãµããŒãã§åŸããã芳枬å€ãADCãéããŠãã€ããªåœ¢åŒã§åŸãããããšã«çç®ãïŒADCãããã¬ãã«ããšã«éä¿¡ããŒã¿éã®çžé¢ãæšå®ããŠå©çšã§ããçµ±ååŸ©å·æ³ãææ¡ããïŒåŸæ¥åŸ©å·æ³ã«ãããçžé¢æšå®ãåçŽã«ãããã¬ãã«ããšã«åå²ããã ãã§ã¯æšå®ç²ŸåºŠãäœããªã埩å·ç¹æ§ãå£åããïŒçžé¢ã®æšå®èª€å·®ã®è§£æãè¡ãïŒãããã¬ãã«ããšã®çžé¢æšå®ã«ãããŠçããåé¡ç¹ãæãã«ããïŒæšå®èª€å·®ã®è§£æã«åºã¥ãïŒçžé¢ã®æšå®ã«ç°¡åãªå·¥å€«ãæœãããšã§å€§å¹
ãªåŸ©å·ç¹æ§ã®åäžãåŸãããæ¹åŒãææ¡ããïŒææ¡æ¹åŒã¯ïŒãããã¬ãã«ããšã«çžé¢ã®å€§ãããæ£è² ãç°ãªãç°å¢äžã§ãé«ã埩å·ç¹æ§ãåŸãããããšã瀺ãïŒ
An Access Control Method for Multipoint Cyclic Data Gathering over a PLC Network
- Y. Ohtomo, T. Yamazato, M. Katayama
- IEEE International Symposium on Power Line Communications and Its Applications (ISPLC), Rio de Janeiro, Brazil
- 2010幎3æ
- https://doi.org/10.1109/ISPLC.20https://doi.org/10.5479914
- This paper proposes a media access control method for a multipoint cyclic data gathering system, in which each node transmits its data to the base-station periodically. In such condition, by broadcasting ACK/NACK signals from the base-station, the proposed method ensures assignment of a time slot for each node once the node succeeds to transfer its data. It is confirmed that the proposed scheme reduces packet collisions and outperforms conventional slotted-ALOHA scheme in throughput of data even with ACK/NACK errors. Furthermore the proposed scheme realizes adaptive slot assignment under cyclostationary channel environment.
å調åäœããè€æ°æ©åšã®ããã®ç¡ç·é信路誀ããèæ
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- è¿è€ç¶æ¬ïŒå±±éæ¬ä¹ïŒçå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, A-5-17, p.119 , ä»å°
- 2010幎3æ
- æ©åšå¶åŸ¡ãžã®ç¡ç·æè¡ã®å°å
¥ã«ã¯ïŒç§»åäœå¶åŸ¡ã®å®¹æåïŒçã¹ããŒã¹ïŒè€æ°æ©åšã®åæé
ä¿¡å¯èœãªã©å€ãã®å©ç¹ãããïŒãããïŒç¡ç·éä¿¡è·¯ã®é信誀ãç¹æ§ãå¶åŸ¡å質ã«äžãã圱é¿ã¯ååã«è©äŸ¡ãããŠããªãïŒç¹ã«å調åäœããè€æ°ã®æ©åšãå¶åŸ¡ããå Žåã¯ïŒåã
ã®æ©åšã®å¶åŸ¡å質ã ãã§ãªãïŒçžäºã®åäœã®åæãèããå¿
èŠãããïŒæ¬çš¿ã§ã¯ïŒåæåäœã®äžäŸãšããŠ2å°ã®å¶åŸ¡å¯Ÿè±¡ãåæã«åãåäœãããç¡ç·å¶åŸ¡ã·ã¹ãã ãèãïŒããããã®å¶åŸ¡ç³»ã仿¹ã®ä¿¡å·ãå©çšããããšã§ïŒåæèª€å·®ç¹æ§ã®æ¹åãå®çŸã§ããããšã瀺ãïŒ
è¡æå°äžçµ±åç§»åéä¿¡ã·ã¹ãã ã«ãããåçè³æºå²åœã«ããåšæ³¢æ°å©çšå¹çã®æ¹å
- é¿è¬åæŽã山鿬ä¹, çå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, B-3-33, p.346
- 2010幎3æ
äžæ¬¡ã·ã¹ãã ä¿¡å·ã®äžç¶ã䌎ãéç³éä¿¡ã·ã¹ãã ã«ãããDirty Paper Codingã®é©çš
- é·çžæœ€, 山鿬ä¹, çå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ,B-17-3,pp.652, ä»å°
- 2010幎3æ
- åšæ³¢æ°å
±çšã®ããã«æ¢å(äžæ¬¡)ã·ã¹ãã ãšäºæ¬¡ã·ã¹ãã ãåãåšæ³¢æ°åž¯åã§åæã«éä¿¡ãè¡ãéç³éä¿¡ã®å®çŸäŸãšããŠïŒèè
ãã¯äºæ¬¡ã·ã¹ãã ãäžæ¬¡ã·ã¹ãã ä¿¡å·ãäžç¶ããæ¹åŒãææ¡ããŠããïŒããããã®æ¹åŒã§ã¯ïŒäžæ¬¡ã·ã¹ãã ã®ä¿¡å·ãå¹²æžãšãªãïŒäºæ¬¡ã·ã¹ãã ã®ç¹æ§ã«å€§ããªåœ±é¿ãäžãããšããåé¡ããã£ãïŒããã§æ¬çš¿ã§ã¯ïŒäºæ¬¡ã·ã¹ãã ã®ç¹æ§æ¹åãå³ãããã«\\\Dirty Paper Coding\\\"(DPC)ãææ¡æ¹åŒã«é©çšããïŒãããŠæ°å€äŸã«ããïŒäžæ¬¡ã·ã¹ãã ã®èª€ãçç¹æ§ã®å£åç¡ãã«äºæ¬¡ã·ã¹ãã ã®ç¹æ§ãæ¹åãããããšã瀺ãïŒ
LEDã¢ã¬ã€ãšé«é床ã«ã¡ã©ãçšããå¯èŠå
éä¿¡ã·ã¹ãã ã®ããã®LEDäœçœ®ã®ãµããã¯ã»ã«æšå®
- åå培, 山鿬ä¹, çå±±æ£æ, åéç¥å, è€äºä¿åœ°, 岡ç°å
- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, A-17-16, p.244, ä»å°
- 2010幎3æ
- LEDã¯åŸæ¥ã®çœç±ç¯ãšæ¯èŒããŠäœæ¶è²»é»åïŒèŠèªæ§ã®è¯ããé·å¯¿åœãšãã£ãå©ç¹ãããïŒLEDä¿¡å·æ©ãæ®åãã€ã€ããïŒLEDã人ã®ç®ã«ã¯èŠããªãçšé«éã«ç¹æ»
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ãã¯ãããŸã§åä¿¡èŒåºŠååŸæ¹æ³ãæ€èšããããšã«ããïŒèª€ãçç¹æ§ãæ¹åããïŒãããïŒå ä¿¡èŒåºŠååŸæã«LEDç¹ç¯äœçœ®ãšæšå®äœçœ®ã«ãããçãããšèª€ãçç¹æ§ãå£åããåé¡ç¹ãããïŒæ¬çš¿ã§ã¯LEDäœçœ®ã®ãµããã¯ã»ã«æšå®ææ³ãææ¡ããããšã§ïŒããæ£ç¢ºãªLEDäœçœ®ãæšå®ãïŒèª€ãçç¹æ§ãæ¹åããïŒ
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- çœæšåº·å»ºïŒ 山鿬ä¹ïŒ çå±±æ£æïŒ åéç¥åïŒ è€äºä¿åœ°ïŒ 岡ç°å
- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, A-4-3, p.76, ä»å°
- 2010幎3æ
- LEDã¯çœç±ç¯ã«æ¯ã¹é·å¯¿åœã§æ¶è²»é»åãäœãïŒçºç±ãå°ãªãçã®å©ç¹ãæã€ããä¿¡å·æ©ãç
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éä¿¡ãšåŒã¶ïŒè»èŒã«ã¡ã©ãšLEDä¿¡å·æ©ãçšããè·¯è»éå¯èŠå
éä¿¡ã§ã¯ä¿¡å·æ©ãåžžã«ã«ã¡ã©ã«æ£é¢ãåããŠãããšã¯éããªãïŒæ¬çš¿ã§ã¯ä¿¡å·æ©ãã«ã¡ã©ã«å¯ŸããŠåŸããŠããå Žåãæ³å®ããŠå®éšãè¡ãåŸãã®åœ±é¿ãBERã§è©äŸ¡ããïŒ
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- äžå®¶ç¥¥å¹³ïŒå±±éæ¬ä¹, çå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, B17-15, p664, ä»å°
- 2010幎3æ
- åçåšæ³¢æ°å²ãåœãŠã«ãã垯åå
±æã«ãããŠã¯ïŒäžæ¬¡ã·ã¹ãã ä¿¡å·ã®æç¡ãæ£ç¢ºã«å€å®ããããšãéèŠã§ããïŒäžå€®å±ïŒFCïŒãè€æ°ã®ããŒãã®ã»ã³ã·ã³ã°çµæãå©çšãå€å®ããå調ã¹ãã¯ãã«ã»ã³ã·ã³ã°ã§ã¯ïŒã¹ããŒã¹ãã€ãã·ãã«ããæ£ç¢ºãªå€å®ãæåŸ
ã§ããïŒåããŒãã®ã»ã³ã·ã³ã°çµæãFCãžå ±åããã«ã¯ã³ã³ãããŒã«ãã£ãã«ãšåŒã°ãã垯åãå¿
èŠãšãªãïŒå調ã¹ãã¯ãã«ã»ã³ã·ã³ã°ã«ãããŠã¯ïŒãã®ã³ã³ãããŒã«ãã£ãã«ã®åšæ³¢æ°è³æºã®æå¹å©çšãéèŠãªèª²é¡ã§ããïŒã³ã³ãããŒã«ãã£ãã«ã®äœ¿çšéãèæ
®ããåŸæ¥ç ç©¶ãšããŠã¯ïŒé次æ€å®ãçšããææ³ãããïŒãã®ææ³ã§ã¯ïŒé次æ€å®ã«ããé«ã確信床ã®çµæãåŸãããŒãã®ã¿ãFCãžå ±åããããšã§ïŒå ±åç·æ°ãæžå°ãïŒããã«åããŒãã®å ±åã¿ã€ãã³ã°ããããããšã§åæå ±åæ°ãå°ãªããªã£ãŠããïŒãã®ææ³ã§ã¯å€å®ã確å®ãããŸã§ã®æéãäžå®ã§ã¯ãªãã£ãïŒããã§é次æ€å®ãè¡ãã»ã³ã·ã³ã°ã«ïŒæã¡åãæéãèšå®ãïŒãã®æç¹ãŸã§ã«FCãåãåã£ãå ±åãåºã«å€å®ããããã®éã¿ä»ãåæå€å®æ³ãææ¡ããïŒãããŠïŒå ±åæ°ååžã®åãã«å¿ããéã¿ä»ããè¡ãããšã§ïŒããé«ãç¹æ§ãåŸãããããšã瀺ãïŒ
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- 平岩士æ, 山鿬ä¹, çå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.ITS2010-45, pp.47-52, , åæµ·é
- 2010幎2æ
- æ¬çš¿ã§ã¯ïŒéä¿¡æ¹åŒã«MC-CDMAãçšããè»è»ééä¿¡ã®ããã®ã«ã«ãã³éä¿¡è·¯æšå®ãææ¡ããïŒè»è»ééä¿¡ã¯èªåŸåæ£åéä¿¡ã§ããïŒéä¿¡è»äž¡æ¯ã«ç°ãªãéä¿¡è·¯ç¹æ§ã瀺ãïŒããã«ïŒéåä¿¡è»äž¡ã®ç§»åã«ããïŒãã«ããã¹ãã§ãŒãžã³ã°ããããã©ãŒã·ãããçããããïŒãã€ãããä¿¡å·éã§ãéä¿¡è·¯ã®å€åãçããïŒæ¬çš¿ã§ã¯ïŒéä¿¡è·¯ã®å€åã«è¿œåŸããããšãç®çã«ïŒéä¿¡è·¯æšå®ã«ã«ã«ãã³ãã£ã«ã¿ãå©çšããïŒ ææ¡ããã«ã«ãã³éä¿¡è·¯æšå®ã§ã¯ïŒã«ã«ãã³ãã£ã«ã¿ã§çãã誀差ã®åœ±é¿ãæããããã«ïŒã«ã«ãã³éä¿¡è·¯æšå®ãšãã€ãããä¿¡å·éã®éä¿¡è·¯ãè£é颿°ãçšããŠæšå®ããéä¿¡è·¯æšå®ã«åºã¥ããçµåéä¿¡è·¯æšå®ã«ããæšå®å€ã®æŽæ°ãè¡ãïŒèšç®æ©ã·ãã¥ã¬ãŒã·ã§ã³ã®çµæããïŒææ¡ããã«ã«ãã³éä¿¡è·¯æšå®ãçšããããšã§éä¿¡è·¯ã®å€åãžã®è¿œåŸãå¯èœã«ãªãïŒè£é颿°ãå©çšããéä¿¡è·¯æšå®ããè¯ãç¹æ§ãåŸãããããšã瀺ãïŒ
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éä¿¡ã·ã¹ãã ã®LEDã¢ã¬ã€éä¿¡æ©æ€åºã»è¿œè·¡ææ³
- åå培, å°æŸ€ä¿ä¹, 山鿬ä¹, çå±±æ£æ, åéç¥å, è€äºä¿åœ°, 岡ç°å
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.ITS2010-47, pp.59-64, åæµ·é
- 2010幎2æ
- æ¬çš¿ã§ã¯LEDã¢ã¬ã€ãéä¿¡æ©ã«ãé«é床ã«ã¡ã©ãåä¿¡æ©ã«çšããå¯èŠå
éä¿¡ã·ã¹ãã ã§è»äž¡èµ°è¡æã«ããã埩å·ã¢ã«ãŽãªãºã ã«ã€ããŠè¿°ã¹ããå
·äœçã«ã¯Mç³»åãçšããä¿¡å·æ©æ€åºææ³ãšãå転信å·ãçšããä¿¡å·æ©è¿œåŸææ³ãææ¡ãããMç³»åãçšããããšã«ãããæ£ç¢ºã«LEDã¢ã¬ã€åè£ãéžå¥ã§ããããšã瀺ãããŸããå転信å·ãçšããããšã§ãåŸæ¥ææ³ãããLEDã®ã¡ãã€ããæžãããäŒéé床ãåäžã§ããããšã瀺ãã
LEDã¢ã¬ã€ãšé«é床ã«ã¡ã©ãçšãã éå±€ç笊å·åå
éä¿¡æ¹åŒã®ããã®é次åå¹²æžé€å»
- å°æŸ€ä¿ä¹, åå培, 山鿬ä¹, çå±±æ£æ, åéç¥å, è€äºä¿åœ°, 岡ç°å
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.ITS2010-46, pp53-58,, åæµ·é
- 2010幎2æ
- LED ã¢ã¬ã€ãšé«é床ã«ã¡ã©ãçšããéå±€ç笊å·åå
空ééä¿¡æ¹åŒã«ãããã¿ãŒã笊å·ãçšãã鿬¡åå¹²æžé€å»ãææ¡ããïŒææ¡ãã鿬¡åå¹²æžé€å»ã§ã¯ïŒãŸãïŒé«åªå
床ããŒã¿ã®åŸ©èª¿ããã³ã¿ãŒã埩å·ãè¡ãïŒãã®é«åªå
床ããŒã¿ãåå€èª¿ãïŒåä¿¡ä¿¡å·ããæžç®ããããšã§é«åªå
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床ããŒã¿ãžã®å¹²æžæåãåãé€ãïŒããããããšã«ããïŒäžåªå
床ããŒã¿ã®èª€ãçç¹æ§ãæ¹åããïŒãŸãïŒãã®å¹²æžé€å»æ³ã®ç¹æ§ã¯é«åªå
床ããŒã¿ã®èª€ãçç¹æ§ïŒã€ãŸãã¿ãŒã笊å·ã®èª€ãçç¹æ§ã«äŸåããïŒããã§ïŒãããŸã§æ¡çšããŠããMaxLogMAP ã¢ã«ãŽãªãºã ã«ããã¿ãŒã埩å·ã§ã¯ç¡ãïŒæ°ãã«LogMAP ã¢ã«ãŽãªãºã ãæ¡çšããããšã§èª€ãçç¹æ§ã®æ¹åãå³ãïŒ
äžæ¬¡ã·ã¹ãã ä¿¡å·ã®äžç¶ã䌎ãéç³éä¿¡ã·ã¹ãã ã«ãããåçäžç¶ã®é©çš
- é·çžæœ€, 山鿬ä¹, çå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.109, no.383 (SR2009-75), pp.9-14, 調åž
- 2010幎1æ
- ã³ã°ããã£ãç¡ç·æè¡ãçšããŠïŒæ¢å(äžæ¬¡)ã·ã¹ãã ãšäºæ¬¡ã·ã¹ãã ãåãåšæ³¢æ°åž¯åã§åæã«éä¿¡ãè¡ãåšæ³¢æ°å
±çšãèããïŒææ¡ããææ³ã§ã¯ïŒäºæ¬¡ã·ã¹ãã ãäžæ¬¡ã·ã¹ãã ã®éä¿¡ä¿¡å·ãäžç¶ããããšã§äžæ¬¡ã·ã¹ãã ã®SNRãåäžããïŒçããäœè£åãäºæ¬¡ã·ã¹ãã ã«å²ãåœãŠåšæ³¢æ°å
±çšãå®çŸããïŒæ¬çš¿ã§ã¯ïŒãã®äžç¶æ¹åŒã®éãã«ããç¹æ§ãžã®åœ±é¿ãè©äŸ¡ããïŒäž¡ã·ã¹ãã ã®ã·ã³ãã«èª€ãçç¹æ§ãè§£æçã«å°åºãïŒåçäžç¶ãçšããããšã§ïŒäžæ¬¡ã·ã¹ãã ã®ç¹æ§ãæªåãããããšç¡ãïŒäžæ¬¡ã·ã¹ãã ãšåçã®èª€ãçã§äºæ¬¡ã·ã¹ãã ãéä¿¡å¯èœã§ããããšã瀺ãïŒ
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å ±åéã®ãã ã®å¿çä¿¡å·èª€ããèæ
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- 倧åäœäžïŒå±±éæ¬ä¹ïŒçå±±æ£æ
- 黿°åŠäŒç ç©¶äŒè³æïŒCMN-10-006ïŒpp.21-26, æ²çž
- 2010幎1æ
- å€å°ç¹ã®ããŒãã§åšæçã«çºçããããŒã¿ãïŒåºå°å±ãé»åç·éä¿¡æè¡ãçšããŠåéããã·ã¹ãã ãèããïŒãã®ãããªã·ã¹ãã ã«ãããŠïŒåºå°å±ãå¿çä¿¡å·ããããŒããã£ã¹ãããããšã§ïŒäžåºŠéä¿¡ã«æåããããŒãã«åšæçã«ã¹ãããå²åœãè¡ãã¢ã¯ã»ã¹å¶åŸ¡ææ³ãææ¡ããïŒã©ã³ãã å²åœãšæ¯ã¹ãŠïŒå€§ããªã¹ã«ãŒããããåŸãããããšã瀺ãïŒãŸãææ¡ææ³ã«ãããŠïŒå¿çä¿¡å·ã«èª€ããçããŠãïŒãã®åœ±é¿ãåé¿å¯èœã§ããããšã瀺ãïŒ
ãªããã£ã«ã«ãããŒãçšããå¯èŠå
éä¿¡ã·ã¹ãã ããã®LEDã¢ã¬ã€è¿œè·¡
- ãã¬ãŒããã£ã³ãã© ãã³ã¿ã«, åé ç¥å, ããããã« ããã©ã ã¡ãã«ãã, å±±é æ¬ä¹, å²¡ç° å, è€äº ä¿åœ°, è°·æ¬ æ£å¹ž
- æ åæ
å ±ã¡ãã£ã¢åŠäŒå¬å£å€§äŒ, æ±äº¬ïŒè浊工æ¥å€§åŠ
- 2009幎12æ
- We propose a visible light road-to-vehicle communication system at intersection as one of ITS technique. In this system, the communication between vehicle and an LED array is approached using LED array as a transmitter, and on-vehicle high-speed camera as a receiver. The LEDs in the transmitter are emitted in 500Hz and those emitting LEDs are captured by a high-speed camera for making communication. Here, the luminance value of LEDs in the transmitter should be captured in consecutive frames to achieve effective communication. For this purpose, first the transmitter should be identified, then it should be tracked in consecutive frames while the vehicle is moving, by processing the images from the high-speed camera. In this paper, we mainly introduce an algorithm to track the transmitter using optical flow and edge information.
è«æã®æžãæ¹è¬åº§
- 山鿬ä¹
- ä¿¡å·å€§åŠã»å·¥ã»é»æ°é»åå·¥åŠç§ãè¬æŒäŒ, ä¿¡å·å€§åŠé»æ°é»åæ±æ£6F 603 ã³ãã¥ããã£
- 2009幎12æ
LEDä¿¡å·æ©éä¿¡ã®ããã®è¿œå°Ÿæ©æ§ãåããè»èŒåä¿¡æ©
- 岡ç°è³¢è©ïŒåéç¥åïŒå±±éæ¬ä¹ïŒå²¡ç°åïŒã¡ãã«ãã ããããã« ããã©ãïŒè€äºä¿åœ°ïŒè°·æ¬æ£å¹ž
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, CS2009-64, pp.77-81, åå€å±
- 2009幎12æ
- æ¬ç 究宀ã§ã¯ïŒåçç°å¢ã§é·è·é¢ã»é«éãªå¯èŠå
éä¿¡ãéæããããã®è»èŒçšåä¿¡æ©ãææ¡ã»è©ŠäœããŠããïŒè©Šäœã·ã¹ãã ã§ã¯ïŒãã©ããã€ãªãŒããåå
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ãããããã©ããã€ãªãŒãã®åæ¹ã«æé ã¬ã³ãºãçšããŠããïŒãŸããã©ããã€ãªãŒãã®èŠéãçããªã£ãŠããããïŒé©åãªæ¹åã«åããªããã°ãããªãïŒãã®ããïŒåžžã«ãã©ããã€ãªãŒããéä¿¡æ©ã®å
ãåä¿¡ã§ããããã«ïŒãããªã«ã¡ã©ãçšããŠè¿œå°ŸããïŒãŸãæ¯åã®åœ±é¿ãèããããããïŒæ¯åè£æ£ã®ããã®æ©æ§ãå¥ã«ä»å ããïŒè©Šäœããåä¿¡æ©ã®åäœã»æ§èœã確ãããããïŒå®è»å®éšã«ãã远尟ïŒéçç°å¢ã§ã®BER枬å®å®éšãè¡ã£ãïŒ
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- ãªãŒã 瀟
- 2009幎11æ
- æ°ã€ã³ã¿ãŒãŠããã·ãã£ã·ãªãŒãºïŒéä¿¡ã»ä¿¡å·åŠçéšéïŒ
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éä¿¡ã®ç©ºéåšæ³¢æ°ç¹æ§ã«åºã¥ã笊å·åæ¹åŒã®æ€èš
- å¢ç°å¹žä»ïŒåéç¥åïŒå±±éæ¬ä¹ïŒå²¡ç°åïŒM.P. Tehrani, è€äºä¿åœ°ïŒè°·æ¬æ£å¹ž
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, CS2009-54, pp.71-76, æ¯ç¬æ¹
- 2009幎11æ
- é«åºŠé路亀éã·ã¹ãã (ITS) ã®ãªãã§ïŒæŽãªãå®å
šæ§ïŒå©äŸ¿æ§ã®åäžã®ããè·¯è»ééä¿¡ã®ç ç©¶ãçãã«è¡ãããŠããïŒæ¬ç ç©¶ã§ã¯ïŒãã®ãªãã§åŸæ¥ç ç©¶ã§ããå¯èŠå
ãçšãéä¿¡æ©ã«LED 亀éä¿¡å·æ©ïŒåä¿¡æ©ã«é«é床ã«ã¡ã©ãçšããã·ã¹ãã ã®ç©ºéåšæ³¢æ°ç¹æ§ã®è§£æãè¡ãïŒè·¯è»ééä¿¡ãæ³å®ããŠããã®ã§ïŒLED 亀éä¿¡å·æ©ãšé«é床ã«ã¡ã©ã®è·é¢ã¯å€åãïŒãäºãã®è·é¢ãé·ããªãã«ã€ããŠã«ã¡ã©ã«ç§»ãããä¿¡å·æ©ã®å€§ãããå°ãããªãïŒãã®ããïŒLED 亀éä¿¡å·æ©ããã®éä¿¡ããŒã¿ã®é«åšæ³¢æåãå£åããããšãèããããïŒãããïŒåŸæ¥ç ç©¶ã§ã¯ã©ã®ããã«å£åããããäžæã§ãã£ãããïŒæ¬ç ç©¶ã§è§£æããïŒãŸãé«é床ã«ã¡ã©ã§ç»çŽ ãšããŠé¢æ£çã«åä¿¡ããããïŒãã€ãã¹ãåšæ³¢æ°ä»¥äžã®é«åšæ³¢æ°æåã«ããïŒç»åã«ã¢ã¢ã¬ãçãéä¿¡ã«æªåœ±é¿ãäžããŠããïŒãã®ããã¢ã¢ã¬ã®åœ±é¿ãæžããããšãæ¬ç ç©¶ã®ç®çã§ããïŒéä¿¡ã®æ¹åãã·ãã¥ã¬ãŒã·ã§ã³ã«ãã確èªããïŒ
è€æ°ã»ã³ãµããŒãã®èŠ³æž¬ããŒã¿éã®çžé¢ãå©çšããçµ±ååŸ©å·æ³ã«é¢ããäžæ€èš - å®èŠ³æž¬ããŒã¿ã®ADCãããã¬ãã«ã«å¿ããçžé¢æšå® -
- å°æå¥å€ªéïŒå±±éæ¬ä¹ïŒçå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.USN2009-42, pp.95-100, ä»å°
- 2009幎10æ
- ç¡ç·ã»ã³ãµãããã¯ãŒã¯ã§ã¯ïŒé«ã芳枬粟床ãåŸãããã«è€æ° ã®ã»ã³ãµããŒãã空éçã«å¯ã«é
眮ããããšãå€ãïŒåããŒãã®èŠ³æž¬ããŒã¿ã¯äºãã«çžé¢ãæããïŒæ¬çš¿ã§ã¯ïŒå®ç°å¢ã«ããã芳枬å€ã®ADCåºåã«çç®ãïŒè€æ°ã»ã³ãµããŒãã®èŠ³æž¬ããŒã¿éã®çžé¢ãADCãããã¬ãã«ããšã«æšå®ããŠå©çšããçµ±ååŸ©å·æ³ãææ¡ããïŒå±å
ã«ãŠå®éã«æž¬å®ãã芳枬ããŒã¿ãã·ãã¥ã¬ãŒã·ã§ã³ã§å©çšãïŒææ¡æ¹åŒã®æ§èœè©äŸ¡ãè¡ãïŒ
M-ary Modulation Scheme Using Separation of Chaotic Dynamics for Noncoherent Chaos-Based Communications
- S. Arai, Y. Nishio, T. Yamazato, S. Ozawa
- International Symposium on Nonlinear Theory and its Applications (NOLTA), Chateraise Gateaux Kingdom Sapporo Hotel & Spa Resort, Sapporo, Japan,
- 2009幎10æ
- This paper proposes a new M-ary modulation scheme for noncoherent chaos-based communications. A chaotic sequence is successive based on the chaotic dynamics. Without the successive sequence based on the chaotic dynamics, general noncoherent systems are very difficult to demodulate the data. However, we consider that the systematic separation and the reconstruction of the chaotic dynamics can be applied as additional information. Namely, M -ary data symbols can be expressed by separating the chaotic dynamics purposely. We carry out computer simulations of the proposed scheme and confirm that a saving of over 3–4 dB is realized in transmitter energy by increasing M.
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- å±±æ¬å°å, 山鿬ä¹, çå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å vol.RCS2009-125, pp.89-93 , ATR
- 2009幎10æ
- ç·è·¯ã«æ²¿ã£ãŠé
眮ããã»ã«ãçšããåè»ä¹å®¢åãç¡ç·éä¿¡ã·ã¹ãã ãèããããŠãŒã¶ã§ããåè»ä¹å®¢ã¯ç·è·¯äžã«å±åšããåè»ãšå
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- 髿£¹ 倧èŒ, åéç¥å, 山鿬ä¹, 岡ç°å, ã¡ãã«ããããããã«ããã©ã, è€äºä¿åœ°, è°·æ¬æ£å¹ž, é«äºå, æšæå¥œå
- æ åã¡ãã£ã¢åŠçã·ã³ããžãŠã ïŒITSïŒ, ã©ãã©ãŒã¬ä¿®å寺
- 2009幎10æ
- ç¹æ®ãªå
éä¿¡çšæ®åçŽ åãçšãïŒLEDä¿¡å·æ©ã®æ€åºããæ¹æ³ãææ¡ããïŒãã®æ®åçŽ åãçšããããšã§ïŒéåžžã®ã«ã¡ã©ãçšããæ€åºæ³ã«æ¯ã¹ïŒæªæ€åºçã誀æ€åºçãæ¹åã§ããïŒ
ä¿¡å·æ©è¿œå°Ÿæ©æ§ãåããå¯èŠå
éä¿¡è»èŒåä¿¡æ©
- 岡ç°è³¢è©, åéç¥å, 山鿬ä¹, 岡ç°å, ã¡ãã«ããããããã«ããã©ã, è€äºä¿åœ°, è°·æ¬æ£å¹ž
- æ åã¡ãã£ã¢åŠçã·ã³ããžãŠã ã(ITS), ã©ãã©ãŒã¬ä¿®å寺
- 2009幎10æ
- LEDä¿¡å·æ©ãšå¯èŠå
éä¿¡ããåä¿¡æ©ã詊äœããïŒé·è·é¢éä¿¡ïŒå€ä¹±å
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Phase Compensation for Narrowband PLC Channels with Cyclic Time-Varying Features
- Y. Sugiura, T. Yamazto, M. Katayama
- Third Workshop on Power Line Communications , Udine, Italy
- 2009幎10æ
- Phase transfer functions of power-line channels often show sharp and periodic variation synchronous to the (double of) mains frequency. This is a result of impedance change of nonlinear devices connected to the power-lines. This manuscript proposes a phase estimation strategy for phase compensation at a receiver under such environment. In the proposed method, phase estimates are calculated using cyclic observation (average) of the channel phase. The numerical examples under periodic phase variation of the channel and cyclostationary noise show that the receiver with the proposed phase estimation scheme outperforms that with the conventional phase estimation, which uses average over the whole observation period without considering the periodic feature of the channel.
LED ã¢ã¬ã€ãšé«é床ã«ã¡ã©ãçšããå¯èŠå
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- 山鿬ä¹
- é»åæ
å ±éä¿¡åŠäŒ åºç€ã»å¢çãœãµã€ãšãã£èª, vol.3, no.2, pp.45-53
- 2009幎10æ
- LEDã¯åå°äœããã€ã¹ã®ããé«éã«èŒåºŠãå¶åŸ¡ããããšãã§ãïŒç
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Decoding of Separately Encoded Multiple Correlated Sources Transmitted over Noisy Channels
- K. Kobayashi, T. Yamazato, M. Katayama
- IEICE Transactions on Fundamentals, vol.E92-A, no.10, pp.2402-2410
- 2009幎10æ
- https://doi.org/10.1587/transfun.E92.A.2402
- We propose an iterative channel decoding scheme for two or more multiple correlated sources. The correlated sources are separately turbo encoded without knowledge of the correlation and transmitted over noisy channels. The proposed decoder exploits the correlation of the multiple sources in an iterative soft decision decoding manner for joint detection of each of the transmitted data. Simulation results show that achieved performance for the more than two sources is also close to the Shannon and Slepian-Wolf limit and large additional SNR gain is obtained in comparison with the case of two sources. We also verify through simulation that no significant penalty results from the estimation of the source correlation in the decoding process and the code with a low error floor achieves good performance for a large number of the correlated sources.
LEDã¢ã¬ã€ãšé«é床ã«ã¡ã©ãçšããå¯èŠå
éä¿¡ã·ã¹ãã ã®ããã®åä¿¡èŒåºŠååŸæ¹æ³
- åå培, 山鿬ä¹, çå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒ åºç€ã»å¢çãœãµã€ãšãã£å€§äŒ, A-17-17, p.181, æ°æœ
- 2009幎9æ
- LEDã¯åŸæ¥ã®çœç±ç¯ãšæ¯èŒããŠäœæ¶è²»é»åïŒèŠèªæ§ã®è¯ããé·å¯¿åœãšãã£ãå©ç¹ãããïŒLEDä¿¡å·æ©ãæ®åãã€ã€ããïŒLEDã人ã®ç®ã«ã¯èŠããªãçšé«éã«ç¹æ»
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ãã¯æ¬ã·ã¹ãã ã«ãããæé«é床ã§ãã128kbpsã®äŒééåºŠãææ¡ããããè¿è·é¢ã§èª€ãçç¹æ§ãå£åããåé¡ç¹ããã£ãããïŒæ¬çš¿ã§ã¯åä¿¡èŒåºŠååŸæ¹æ³ã工倫ããããšã§ãã®åé¡ã解決ããè¿è·é¢ã§ã誀ãçç¹æ§ãæ¹åããïŒ
è€æ°ã»ã³ãµããŒãã®ADCåºåãããéã®çžé¢æšå®ãšçµ±ååŸ©å·æ³ã«é¢ããäžæ€èš
- å°æå¥å€ªéïŒå±±éæ¬ä¹ïŒçå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒ éä¿¡ãœãµã€ãšãã£å€§äŒ, B-20-7, p.388, æ°æœ
- 2009幎9æ
- ç¡ç·ã»ã³ãµãããã¯ãŒã¯ã§ã¯å€æ°ã®ã»ã³ãµããŒããå¯ã«é
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å ±ã埩å·åšéã§äºãã«äžŠåã«äº€æããªããããè¿ã埩å·ãè¡ãããšã§ïŒå€§ããªå©åŸãåŸãããçµ±ååŸ©å·æ³ãææ¡ãããŠããïŒãããã¯ãã¹ãŠã®ããããåçšåºŠã®çžé¢ãæããå Žåãæ±ã£ãŠããïŒäžæ¹ïŒå®ç°å¢ã§ã®ã»ã³ã·ã³ã°ãèããå ŽåïŒã»ã³ãµã®èŠ³æž¬å€ã¯ADCãéããŠãã€ããªåœ¢åŒã§ååŸãããïŒADCåºåã®äžäœãããã¯èŠ³æž¬å€ã«å€§ããªå€åãèµ·ãã£ãå Žåã«ããå€åããïŒèŠ³æž¬å€ã®å€åã¯äž»ã«äžäœãããã«çŸãããããããã¬ãã«ããšã«çžé¢ã®å€§ãããç°ãªãïŒæ¬çš¿ã§ã¯ãããã¬ãã«ããšã«çžé¢ãæšå®ããŠå©çšããçµ±ååŸ©å·æ³ãææ¡ããïŒ
Cognitive Radio with Relay of a Primary Signal and Piggyback Modulation
- J. Naganawa, T. Yamazato, M. Katayama
- IEEE International Symposium on Personal, Indoor and Mobile Radio Communication (PIMRC), pp.147-151 , Tokyo, Japan
- 2009幎9æ
- https://doi.org/10.1109/PIMRC.2009.5450056
- This manuscript proposes a cognitive radio system that shares a frequency with an existing primary system. In the proposed method, a secondary transmitter relays the primary signal and piggybacks its own data on it. Symbol error probabilities of the system are derived analytically. The result shows that the proposed system can communicate at a relatively high speed on the same frequency of the primary system without harm to it.
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éä¿¡ã«ããã空éåšæ³¢æ°ç¹æ§ã«åºã¥ã笊å·åæ¹åŒã®æ€èš
- å¢ç°å¹žä»ïŒåéç¥åïŒå±±éæ¬ä¹ïŒå²¡ç°åïŒM.P. Tehrani, è€äºä¿åœ°ïŒè°·æ¬æ£å¹ž
- 黿°é¢ä¿åŠäŒæ±æµ·æ¯éšé£å倧äŒ, O-438
- 2009幎9æ
å
éä¿¡çšæ®åçŽ åãçšããè·¯è»éå
éä¿¡ã®æ€èš
- 髿£¹å€§èŒïŒåéç¥åïŒå±±éæ¬ä¹ïŒå²¡ç°åïŒM.P. Tehrani, è€äºä¿åœ°ïŒè°·æ¬æ£å¹ž
- 黿°é¢ä¿åŠäŒæ±æµ·æ¯éšé£å倧äŒ, O-441
- 2009幎9æ
LEDä¿¡å·æ©ãçšããå¯èŠå
éä¿¡ã®ããã®è»èŒåä¿¡æ©
- 岡ç°è³¢è©ïŒåéç¥åïŒå±±éæ¬ä¹ïŒå²¡ç°åïŒM.P. Tehrani, è€äºä¿åœ°ïŒè°·æ¬æ£å¹ž
- 黿°é¢ä¿åŠäŒæ±æµ·æ¯éšé£å倧äŒ, O-439
- 2009幎9æ
Traffic Prediction Scheme for Resource Assignment of Satellite/Terrestrial Frequency Sharing Mobile Communication System
- T. Aman, T. Yamazato, M. Katayama
- International Workshop on Satellite and Space Communications (IWSSC), Siena-Tuscany, Italy
- 2009幎9æ
- https://doi.org/10.1109/IWSSC.2009.5286430
- The recent development of large aperture on-board multi-beam antennas enables a small-size, low-powered and cellular phone like hand-held terminal as a satellite earth terminal. A single mobile terminal can communicate to both mobile satellite systems and terrestrial systems depend upon his location, QoS and availability of resources among satellite and terrestrial communication systems. In this paper, we propose a new traffic prediction scheme for the integrated satellite/terrestrial frequency sharing mobile communication system. The system shares a common frequency bandwidth in order to enhance the total capacity by a dynamic bandwidth allocation. A key for this allocation depends on a traffic prediction scheme of a few hundreds of terrestrial cells under a footprint of a satellite with a large aperture onboard multi-beam antennas. We propose three traffic predictors based on neural networks for dynamic resource allocation. The performances of the proposed schemes are evaluated in terms of the Relative Traffic Prediction Error and Maximum Traffic Prediction Error by the computer simulation. For the evaluation, we adopt the actual traffic statistic published by Ministry of Internal Affairs and Communications of Japan with population density of terrestrial cells based on the actual population of Aichi, Japan. As results, average traffic prediction error of less than 0.25 is achieved for the prediction interval of one hour, enough for dynamic resource allocation.
TOA UWB Position Estimation with Two Receivers and a Set of Known Reflectors
- J. Kietlinski-Zaleski, T. Yamazato, M. Katayama
- International Conference on Ultra-Wideband (ICUWB), pp.376-380, Vancouver, Canada
- 2009幎9æ
- https://doi.org/10.1109/ICUWB.2009.5288686
- Ultra-Wideband is an attractive technology for short range positioning, especially indoors. However, for normal Time of Arrival(ToA) positioning, at least 3 receivers with unblocked direct path to the transmitter are required. A requirement that is not always met. In this work, a novel algorithm for ToA positioning using only 2 receivers is presented. This is possible by exploiting reflections from a set of known flat reflectors, for example ceiling and walls. The proposed algorithm was tested using self-developed UWB propagation simulator testbed.
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- èäº äŒžå€ªé, å±±é æ¬ä¹, å°æ²¢ æ
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- å¹³æ21幎 黿°åŠäŒ é»åã»æ
å ±ã» ã·ã¹ãã éšé倧äŒ, 埳島倧åŠ
- 2009幎9æ
- æ¬çš¿ã§ã¯ïŒéä¿¡æ©ã«LEDä¿¡å·æ©ãïŒåä¿¡æ©ã«è»èŒã«ã¡ã©ãçšããå¯èŠå
éä¿¡ã«çç®ãïŒäº€éä¿¡å·ã«ãããç»ååŠçã«ã€ããŠè¿°ã¹ãïŒãŸãïŒåä¿¡æ©ã«ã«ã¡ã©ãçšããããšã§çããç¹æ®ãªãã£ãã«ç¹æ§ã«çç®ããŠææ¡ãããéå±€ç笊å·åã«ã€ããŠè¿°ã¹ïŒç»ååŠçã«ããæ¹åçã®æ€èšãè¡ãïŒ
LEDã¢ã¬ã€ãšé«é床ã«ã¡ã©ãçšããå¯èŠå
éä¿¡ã·ã¹ãã ã®äŒééåºŠã®æ€èš
- åå培, 山鿬ä¹, çå±±æ£æ
- 第11å DSPSæè²è
äŒè°, pp.45-46, æ±äº¬
- 2009幎9æ
- æ¬çºè¡šã§ã¯LEDã¢ã¬ã€ãéä¿¡æ©ã«ãé«é床ã«ã¡ã©ãåä¿¡æ©ã«çšããå¯èŠå
éä¿¡ã·ã¹ãã ã«ã€ããŠè¿°ã¹ããLEDã¯åŸæ¥ã®çœç±ç¯ãšæ¯èŒããŠäœæ¶è²»é»åãèŠèªæ§ã®è¯ããé·å¯¿åœãšãã£ãå©ç¹ããããLEDä¿¡å·æ©ãæ®åãã€ã€ãããLEDã¯åå°äœããã€ã¹ã§ããããã人ã®ç®ã«ã¯èŠããªãã»ã©é«éã«ç¹æ»
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éä¿¡ã«ãããäŒéé床ã«ã€ããŠã®èå¯ãè¡ããèŒåºŠè£æ£ãèŒåºŠæœåºæ¹æ³ã工倫ããããšã«ããæ¬ã·ã¹ãã ã§ã®æé«é床ã§ãã128kbpsãéæã§ããã·ã¹ãã ã«ã€ããŠç޹ä»ããã
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- 平岩士æ, 山鿬ä¹, çå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒ åºç€ã»å¢çãœãµã€ãšãã£å€§äŒ, A-17-15, p.179, æ°æœ
- 2009幎9æ
- è»è»ééä¿¡ã¯ïŒè»äž¡éã®éä¿¡ã«ããå®å
šæ§ãå¹çæ§ã®åäžãç®çãšããŠããïŒæ¬çš¿ã§ã¯åæã«å€æ°ã®è»äž¡ãšéä¿¡ãã§ããMC-CDMAãçšããè»è»ééä¿¡ã®ããã®ãã£ãã«æšå®ã«ã€ããŠæ€èšããïŒãã£ãã«æšå®ã§ã¯ãã€ãããä¿¡å·ãå©çšããŠæšå®ãè¡ãããšãå€ãïŒãããïŒè»è»ééä¿¡ã®ãã£ãã«ã¯è»äž¡ã®ç§»åã«ãããããã©ãŒã·ããããã§ãŒãžã³ã°ãªã©ã®åœ±é¿ã«ããæã
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åå€å±å€§åŠã«ããã OCW ã®æŽ»çš
- 山鿬ä¹
- å¹³æ21å¹ŽåºŠå·¥åŠæè²ç ç©¶è¬æŒäŒè¬æŒè«æéïŒ10-219, åå€å±å€§åŠ
- 2009幎8æ
å·»é èšïœåµåïŒïŒïŒå·ãè¿ããŠïœåæè«æèªBã¯åªããéä¿¡æè¡ã»ç ç©¶ãèãã
- 山鿬ä¹
- é»åæ
å ±éä¿¡åŠäŒè«æèªïŒVol. J92-BïŒNo. 8ïŒpp. 1211-1211ïŒ
- 2009幎8æ
Detection of LED Traffic Light by Image Processing for Visible Light Communication System
- H.C. N. Premachandra, T. Yendo, T. Yamazato, T. Fujii, M. Tanimoto, Y. Kimura
- IEEE Intelligent Vehicles Symposium (IV), pp.179-184, Kempinski Hotel Xi\'an, Shaanxi, China
- 2009幎8æ
- https://doi.org/10.1109/IVS.2009.5164274
- We propose a visible light road-to-vehicle communication system at intersection for ITS. In this system, the communication between vehicle and a LED traffic light is approached using LED traffic light as the transmitter, and on-vehicle high-speed camera as the receiver. The LEDs in the transmitter are emitted with 500Hz and the images of those emitting LEDs are captured by a high-speed camera for conducting communication. In this communication, it is extremely necessary to find the transmitter and detect it for consecutive frames while vehicle is moving. In this paper, we introduce proposals for finding and detecting it for consecutive frames by image processing. Experimental results using appropriate images showed the effectiveness of the proposal.
Edge-Based Tracking of an LED Traffic Light for a Road-to-Vehicle Visible Light Communication System
- H.C. N. Premachandra, T. Yendo, M. P. Tehrani, T. Yamazato, T. Fujii, M. Tanimoto, Y. Kimura
- Journal of Broadcast Engineering published by KoSBE, the Korean Society for Broadcast Engineers, Vol. 14, No. 4, pp.475-487, July 2009
- 2009幎7æ
- We propose a visible light road-to-vehicle communication system at intersection as one of ITS technique. In this system, the communication between vehicle and a LED traffic light is approached using LED traffic light as a transmitter, and on-vehicle high-speed camera as a receiver. The LEDs in the transmitter are emitted in 500Hz and those emitting LEDs are captured by a high-speed camera for making communication. Here, the luminance value of each LED in the transmitter should be found for consecutive frames to achieve effective communication. For this purpose, first the transmitter should be identified, then it should be tracked for consecutive frames while the vehicle is moving, by processing the images from the high-speed camera. In our previous work, the transmitter was identified by getting the subtraction of two consecutive frames. In this paper, we mainly introduce an algorithm to track the identified transmitter in consecutive frames. Experimental results using appropriate images showed the effectiveness of the proposal.
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å ±åéã®ããã®é»åç·éä¿¡ã·ã¹ãã ã«ãããã¢ã¯ã»ã¹å¶åŸ¡ææ³
- 倧åäœäž, 山鿬ä¹, çå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.WBS2009-13, pp.37-42, é岡
- 2009幎7æ
- é»åç·éä¿¡æè¡ãçšããŠïŒå€å°ç¹ã®åå±ã§åšæçã«çºçããããŒã¿ãäžå€®å±ãåéããã·ã¹ãã ãèããïŒæåå²ããããã£ãã«ã®åã¹ããããåå±ã«å²ãåœãŠãã¢ã¯ã»ã¹å¶åŸ¡ææ³ãèããïŒåå±çžäºã®ä¿¡å·æ€åºãäžå®å
šã§ïŒïŒ£ïŒ³ïŒïŒ¡ãå©çšã§ããªããããªç°å¢ã«ãããŠãïŒäžå€®å±ãåå±ãžã®å¿çä¿¡å·ããããŒããã£ã¹ãããããšã§ïŒäžåºŠéä¿¡ã«æåããããŒãã«åšæçã«ã¹ãããããå²ãåœãŠå¯èœãªææ³ãææ¡ããïŒã©ã³ãã å²åœãšæ¯ã¹ãŠïŒããå€ãã®åå±ãéä¿¡å¯èœã§ããããšïŒæéã®çµéã«äŒŽãïŒåå±ã®ä¿¡å·ã®è¡çªç¢ºçãæžå°ããããšçãæããã«ããïŒãŸãåšæå®åžžéé³äžã§æ¬ææ³ãå©çšãããšïŒé©å¿çãªã¹ãããå²åœãèªåçã«è¡ããããšã瀺ããïŒ
æéåšæ³¢æ°åæ£éä¿¡è·¯ã«ãããBFDM/OQAMã®ããã®Kalmanéä¿¡è·¯æšå®åš
- ã¢ã³ãŽã« ãã€ã«ãã¬ã, 山鿬ä¹, çå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol. RCS2009-50, 125-130,, åå€å±
- 2009幎6æ
- éªçŽäº€åšæ³¢æ°åå²å€é/ãªãã»ããQAM (BFDM/OQAM)ã¯ïŒã¹ãã¯ãã«å¹çãæå€§ãšãªããšããã§ïŒã¬ãŠã¹ãã«ã¹ãæ¡çšããããšãã§ããïŒãã®ããïŒç§»åäœç°å¢ã®ããã«éä¿¡è·¯ãæéå€åããæéåšæ³¢æ°åæ£éä¿¡è·¯ã§ãè¯å¥œãªèª€ãçç¹æ§ã瀺ãïŒãããïŒç«¯æ«ãéåžžã«é«éç§»åããŠããç°å¢äžã§ã¯ç¹æ§ãå£åããããïŒãã®å£åãæå¶ããããã®éä¿¡è·¯çåãšéä¿¡è·¯æšå®ãå¿
èŠãšãªãïŒæ¬è«æã§ã¯ïŒBFDM/OQAM ã®ããã®Kalmanãã£ã«ã¿ã«åºã¥ãæ°ããéä¿¡è·¯æšå®åšãææ¡ããïŒææ¡ããKalmanéä¿¡è·¯æšå®åšã§ã¯ïŒãŸãïŒãã¬ãŒãã³ã°ç³»åãçšããŠéä¿¡è·¯ã®åæç¶æ
ãæšå®ããïŒæ¬¡ã«ïŒåææšå®å€ãçšãïŒKalmanãã£ã«ã¿ã«ããéä¿¡è·¯ã®æšå®ãšè¿œåŸãè¡ãïŒææ¡ããKalmanéä¿¡è·¯æšå®åšã®æå¹æ§ãã·ãã¥ã¬ãŒã·ã§ã³ã«ãã£ãŠæ±ããç·åMSEç¹æ§ã§è©äŸ¡ããïŒ
Channel Estimation and Tracking Schemes for the Pulse-Shaping OFDM Systems
- B. Mongol, T. Yamazato, M. Katayama
- IEEE International Conference on Communications (ICC), SPC-10-4, Dresden, Germany
- 2009幎6æ
- https://doi.org/10.1109/ICC.2009.5198817
- Robust channel estimation scheme is essential for pulse-shaping OFDM systems in the multipath mobile environment. This paper proposes three types of channel estimation schemes for the general class of pulse-shaping OFDM systems. The first two types are suboptimal low-complexity maximum likelihood estimators. The last type is adaptive Kalman filter channel estimator. We numerically evaluate the performance of each estimator using computer simulation.
No Redundant Error-Correcting Scheme Using Chaotic Dynamics for Noncoherent Chaos Communications
- S. Arai, Y. Nishio, T. Yamazato
- IEEE International Symposium on Circuits and Systems (ISCAS), pp.2633-2636, Taipei, Taiwan
- 2009幎5æ
- https://doi.org/10.1109/ISCAS.2009.5118342
- This paper proposes the error-correcting scheme without redundancy sequences based on the chaotic dynamics for noncoherent chaos communications. We generate successive chaotic sequences from the identical chaotic map. And for the next sequence we set the initial value to the end value of the former sequence. By such way we can create the successive chaotic sequences having the same chaotic dynamics. This feature gives the receiver additional information to correctly recover the received noisy signal. Therefore, by analyzing the chaotic dynamics at the receiver, it is possible to improve the error performance without redundancy signal. As results of computer simulations, we confirm about 3 dB gain in BER performance as compared with the conventional suboptimal receiver when using the short chaotic sequence length per 1 bit.
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- å°æå¥å€ªéïŒå±±éæ¬ä¹ïŒçå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.MoMuC2009-2, pp.7-12, æ²çž
- 2009幎5æ
- ç¡ç·ã»ã³ãµãããã¯ãŒã¯ã§ã¯ïŒé«ã芳枬粟床ãåŸãããã«å€æ°ã®ã»ã³ãµããŒãã空éçã«å¯ã«é
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ã«ãŠå®éã«æž¬å®ãã芳枬ããŒã¿ãã·ãã¥ã¬ãŒã·ã§ã³ã§å©çšããããšã«ãã£ãŠå®ç°å¢ãæ¬äŒŒçã«å®çŸãïŒææ¡åŸ©å·æ³ã®æ§èœè©äŸ¡ãè¡ãïŒ
å調ã»ã³ã·ã³ã°ã·ã¹ãã ã«ããããïŒãããã®æ
å ±æ¬ èœã®åœ±é¿è©äŸ¡ãšç¹æ§æ¹åææ³
- 髿¢šæ
人ïŒå±±éæ¬ä¹ïŒçå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.109, no.61 (SR2009-5), pp.75-79, , æ°æœ
- 2009幎5æ
- ç¡ç·ã·ã¹ãã ã«å²åœãŠæžã¿ã§ãã垯åã«ãããŠãïŒããåšæ³¢æ°ãå®éã«ã¯å©çšãããŠããªãæéãå ŽæãããïŒãã®ãããªç©ºãåšæ³¢æ°ãä»ã®ã·ã¹ãã ãå©çšããåšæ³¢æ°å
±çšã¯ïŒåšæ³¢æ°è³æºéŒè¿«ã®å¯Ÿçã®ã²ãšã€ã§ããïŒãããå®çŸããã«ã¯ïŒç©ºãåšæ³¢æ°ã®å€å®ïŒããªãã¡åªå
æš©ãæã€ä¿¡å·ã®ç¢ºå®ãªæ€åºãäžå¯æ¬ ã§ããïŒãã®ããã«ïŒè€æ°ã®ã»ã³ãµããŒããå©çšããããšã§ïŒåªå
ä¿¡å·ã®ãã§ãŒãžã³ã°ããã€ãºã«ããæ€åºå€±æã®å¯èœæ§ã®äœæžãå³ãå調ã»ã³ã·ã³ã°æè¡ã®ç ç©¶ãçãã«è¡ãããŠããïŒãããïŒå調ã»ã³ã·ã³ã°ã®ç ç©¶ã®å€§åã¯ïŒã»ã³ãµããŒãã«ãããåªå
ä¿¡å·åä¿¡ã«é¢ãããã®ã§ããïŒããã«å¯Ÿãæ¬çš¿ã§ã¯ïŒã»ã³ãµããŒããšããããã®ããŒã¿ãéçŽãããã¥ãŒãžã§ã³ã»ã³ã¿éã«çç®ããïŒåªå
ä¿¡å·ã®åœ¢åŒãéä¿¡æ
å ±ã«é¢ãã詳现ãªç¥èç¡ãã«å®çŸå¯èœãªïŒã»ã³ãµããŒãã«ããããšãã«ã®ãŒæž¬å®ã«åºã¥ãä¿¡å·æ€åºæ¹æ³ã«ãããŠïŒãã§ãŒãžã³ã°ãã·ã£ããŒã€ã³ã°ïŒæ
éãªã©ã«ããããŒãããã®æ
å ±æ¬ èœãå調ã»ã³ã·ã³ã°ã·ã¹ãã ã®èª€èŠå ±ç¢ºç--èŠéã確çç¹æ§ã«äžãã圱é¿ãè§£æçã«æããã«ããïŒããã«ïŒãã¥ãŒãžã§ã³ã»ã³ã¿ã«ãããŠïŒæ
å ±æ¬ èœã®ç¶æ³ã«å¿ããåŠçããããªãããšã«ããç¹æ§æ¹åææ³ãææ¡ããïŒ
Bit and Power Allocation for Power-Line Communications under Nonwhite and Cyclostationary Noise Environment
- N. Sawada, T. Yamazato, M. Katayama
- IEEE International Symposium on Power Line Communications and Its Applications (ISPLC), pp.307-312, Dresden, Germany
- 2009幎4æ
- https://doi.org/10.1109/ISPLC.2009.4913448
- This manuscript discusses the adaptive OFDM system for narrow-band power-line communications with nonwhite and cyclostationary noise environment. The bit and power allocation algorithm is proposed with the considerations on the cyclostationarity of power-line noise. Numerical evaluation shows that the proposed method can improve the average BER performance under PLC noise environment.
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- èäºäŒžå€ªéïŒéç¬ç¥¥å¹³ïŒåå培ïŒå±±éæ¬ä¹ïŒåéç¥åïŒè€äºä¿åœ°ïŒè°·æ¬æ£å¹žïŒæšæå¥œå
- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, A-17-19, p.311, æŸå±±
- 2009幎3æ
- æ¬ç ç©¶ã§ã¯ïŒéä¿¡æ©ã«LEDã¢ã¬ã€ïŒåä¿¡æ©ã«è»èŒé«é床ã«ã¡ã©ãçšããè·¯è»éå¯èŠå
éä¿¡ã«çç®ããïŒããã¯ïŒLEDãåå°äœããã€ã¹ã§ïŒé«éã«èŒåºŠãå¶åŸ¡ããããšãå¯èœã§ããããšããïŒäººéã®ç®ã«ã¯èŠããªãã»ã©é«éã«å€èª¿ãããããšã§éä¿¡ãå®çŸããã·ã¹ãã ã§ããïŒã«ã¡ã©ãå©çšããäžã§ïŒéä¿¡æ©ãæ®åœ±ããç»åããLEDã®èŒåºŠãæœåºããããšãïŒããŒã¿åŸ©èª¿ãè¡ãäžã§éåžžã«éèŠãªåäœã§ããïŒããããªããïŒéä¿¡è·é¢ã®å€åã«ãããã£ãŠïŒæ®åœ±ç»åã«åãLEDã¢ã¬ã€ã®ãµã€ãºãïŒLEDã®èŒåºŠãç°ãªãããïŒããŒã¿ãåä¿¡ãã床ã«èŒåºŠã®è£æ£ãè¡ãå¿
èŠãããïŒæ¬ç ç©¶ã§ã¯ïŒåã
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ISOMACãããŒã¹ãšããã»ã³ãµãããã¯ãŒã¯ã®ããã®äœæ¶è²»é»åTDMA-MACãããã³ã«
- é³å®ïŒå±±éæ¬ä¹ïŒçå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, B-20-42, p.646, æŸå±±
- 2009幎3æ
åšæçæå€æ§ãæã€ç垯åé»åç·éä¿¡è·¯ã®ããã®äœçžè£åæ¹åŒ
- ææµŠäœ³æ, 山鿬ä¹, çå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.108, no.472, pp.513-518, åœé€š
- 2009幎3æ
- é»åç·ã«æ¥ç¶ããã黿°æ©åšã®ã€ã³ããŒãã³ã¹å€åçã®ãã, é»åç·éä¿¡è·¯ã®äŒæ¬ç¹æ§ã¯ïŒåçšé»æºã®ååšæã«åæããåšæçã§æ¥å³»ãªæéå€åã瀺ãããšããã. ãã®ãããªéä¿¡è·¯ã®äœçžå€åã«è¿œåŸããäœçžè£åãè¡ãããïŒé»æºé»å§ã®åšæ³¢ æ°ã«åæããåšæå¹³åãå©çšããäœçžæšå®ææ³ãææ¡ããïŒæ°å€äŸã«ããïŒç垯åé»åç·éä¿¡ã·ã¹ãã ã®äŒæ¬è·¯äœçžå€åç¹æ§ãšåšæå®åžžéé³ãæš¡æ¬ããç°å¢äžã«ãããŠïŒèŠ³æž¬åºéå
ã®äŒæ¬è·¯äœçžã®å¹³åå€ã«è¿œåŸããåŸæ¥ã®äœçžæšå®ææ³ãå©çšããå Žåã«æ¯ã¹ïŒææ¡ææ³ãå©çšããå Žåã®æ¹ãïŒããè¯ã誀ãçç¹æ§ãå®çŸã§ããããšã瀺ãïŒ
TOA UWB Position Estimation with 2 receivers and one known reflector
- J. Kietlinski-Zaleski, T. Yamazato, M. Katayama
- Technical Report of IEICE, vol.WBS2008-90, pp.211-216, Hakodate, Japan
- 2009幎3æ
- Ultra-Wideband is an attractive technology for short range positioning, especially indoors. However, for normal Time of Arrival(ToA) positioning, at least 3 receivers with unblocked direct path to the transmitter are required. A requirement that is not always met. In this work, a novel algorithm for ToA positioning using only 2 receivers is presented. This is possible by exploiting reflections from one known flat reflector, for example ceiling or wall. The proposed algorithm was tested using self-developed UWB propagation simulator testbed.
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éä¿¡ã·ã¹ãã ã®é«éå
- åå培ïŒèäºäŒžå€ªéïŒéç¬ç¥¥å¹³ïŒå±±éæ¬ä¹ïŒåéç¥åïŒè€äºä¿åœ°ïŒè°·æ¬æ£å¹žïŒæšæå¥œå
- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, A-17-18, p.310, æŸå±±
- 2009幎3æ
- LEDã¯åŸæ¥ã®çœç±ç¯ãšæ¯èŒããŠäœæ¶è²»é»åïŒèŠèªæ§ã®è¯ããé·å¯¿åœãšãã£ãå©ç¹ãããïŒLEDä¿¡å·æ©ãæ®åãã€ã€ããïŒLEDã人ã®ç®ã«ã¯èŠããªãçšé«éã«ç¹æ»
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éä¿¡ã·ã¹ãã ãèããïŒåŸæ¥ã®ã·ã¹ãã ã§ã¯32kbpsã®äŒéé床ãéæããŠããããå®ç°å¢ã§ã®å¯èŠå
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èŠãª5å€ã®èŒåºŠå€ãOOKãããããšã§åŸãŠãããã®ããPWMãããŠåŸãããšã§åŸæ¥ã®äŒéé床ã®ïŒåã®é«éåãå®çŸãã.
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- å°æ¥å瀌ç·ïŒå±±éæ¬ä¹, çå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, WBS2008-83, vol.108, no.474, pp.167-172, åœé€š
- 2009幎3æ
- æ¬çš¿ã§ã¯,ç¡ç·å¶åŸ¡ã·ã¹ãã ã«ãããŠïŒç¡ç·éä¿¡è·¯ã®ç¹æ§ãå¶åŸ¡å質ã«äžãã圱é¿ãæããã«ããããïŒãã£ãŒãããã¯ã«ãŒãã«ãããŠïŒå¶åŸ¡å
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éã®ãã£ãŒãããã¯ãç¡ç·éä¿¡ã«ãã£ãŠè¡ãå転ååç«æ¯åã®å¶åŸ¡ã·ã¹ãã ãèããïŒç¡ç·éä¿¡è·¯ã«äŒé誀ããäžæ§ã«çºçããã¢ãã«ãšããŒã¹ãçã«çºçããã¢ãã«ã®åæ¹ãçšãïŒäŒéã¬ãŒããšäŒé誀ãç¹æ§ãå¶åŸ¡ã·ã¹ãã ãžäžãã圱é¿ã®è©äŸ¡ãè¡ãïŒãã®çµæïŒå¶åŸ¡å質ã«ãããŠäŒé誀ããååšããŠãïŒäŒéã¬ãŒãã®åäžã«ããå¶åŸ¡å¶åŸ¡ã·ã¹ãã ã¯å®å®ããŠå¶åŸ¡å¯èœã§ãããããªèª€ãçã®ç¯å²ãååšããããšã瀺ããïŒãŸãïŒãã®ããã«äŒéé床ã®åäžã§äŒé誀ããè£åããŠãããããªé åã§ã¯ïŒäŒé誀ãã®ããŒã¹ãæ§ãå¶åŸ¡å質ã«äžãã圱é¿ã倧ããããšãæããã«ããïŒ
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- é»åæ
å ±éä¿¡åŠäŒ ååœæ¯éš åŠçåãè¬æŒäŒ, 埳島倧åŠ
- 2009幎2æ
IEEEã®major conferenceã§è«æãéãããã«ã¯
- 山鿬ä¹
- åŸ³å³¶å€§åŠ & åå€å±å€§åŠ IEEE Student Branches Joint-Workshop, 埳島倧åŠ
- 2009幎2æ
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- é¿è¬åæŽ, 山鿬ä¹, çå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å,vol.108, no.440, pp.55-60, å¥è¯
- 2009幎2æ
- è¡æç§»åéä¿¡ãšå°äžç§»åéä¿¡ã®çžäºè£å®ïŒåšæ³¢æ°å©çšå¹çã®åäžãšããç®çã®ããã«è¡æ/å°äžåšæ³¢æ°å
±çšç§»åéä¿¡ã·ã¹ãã ãçç®ãããŠããïŒåã·ã¹ãã ã§ã¯è¡æç§»åéä¿¡ïŒããã³å°äžç§»åéä¿¡ã§åšæ³¢æ°å
±çšãè¡ãã®ã§ïŒãã©ããã¯ã«å¿ããåçè³æºå²åœãè¡ãããšã«ããåšæ³¢æ°å©çšå¹çã®åäžãå¯èœãšãªãïŒãããïŒåçè³æºå²åœãå¹çè¯ãè¡ãããã«ã¯ãã©ããã¯äºæž¬ãå¿
èŠã§ããïŒæ¬ç ç©¶ã§ã¯ãã¥ãŒã©ã«ãããã¯ãŒã¯ãçšãããã©ããã¯äºæž¬ææ³ãææ¡ããïŒ
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- 平岩士æïŒåç°ç¯€åïŒå±±éæ¬ä¹ïŒçå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒè«æèª, vol.J92-B, no.1, pp.367-369
- 2009幎1æ
- æ¬çš¿ã§ã¯MC-CDMAãçšããè»è»ééä¿¡ã«é©ããSC/MMSEã¿ãŒãçåãææ¡ããïŒææ¡æ¹åŒã§ã¯åè»äž¡ã®ãã£ãã«äŒé颿°ã®éãã«ããé»åå·®ã«çç®ãïŒSC/MMSEã¿ãŒãçåã®MMSEãã£ã«ã¿ãä¿®æ£ããïŒããã«ããåä¿¡å¯èœå°æ°ãå¢å ããïŒ
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- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.USN2008-76, pp.83-87, åå€å±
- 2009幎1æ
- ååéä¿¡ã¯è€æ°ã®ç¡ç·ããŒããååããŠåäžã®æ
å ±ãéä¿¡ããããšã«ããäŒéè·é¢ãå»¶é·ãïŒåããŒãã®æ¶è²»é»åãäœæžã§ããïŒæ¬çš¿ã§ã¯ïŒè€æ°ã®ã¯ã©ã¹ã¿ã«åå²ãããç¡ç·ã»ã³ãµãããã¯ãŒã¯ã«ååéä¿¡ãé©çšããããšãèããïŒã¯ã©ã¹ã¿éååéä¿¡ãè¡ãã«ã¯åäžã¯ã©ã¹ã¿å
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Detecting and A LED Traffic Light for Visible Light Communication System
- H.C. N. Premachandra, T. Yendo, T. Yamazato, T. Fujii, M. Tanimoto, Y. Kimura
- International Workshop on Advanced Image Technology (IWAIT), Korean Hall of Science and Technology, Seoul, Kore
- 2009幎1æ
- In this paper, we propose a visible light road-to-vehicle communication system at intersection as one of ITS technique. In this system, the communication between vehicle and a LED traffic light is approached using LED traffic light as the transmitter, and on-vehicle high-speed camera as the receiver. The LEDs in the transmitter are emitted with 500Hz and those emitting LEDs are captured by a high-speed camera for making communication. The images from the high-speed camera are processed to get luminance value of each LED in the transmitter. For this purpose, first transmitter should be found, then it should be tracked for each frame, and the luminance value of each LED in the transmitter should be captured. In our previous work, transmitter was found by getting the subtraction of two consecutive frames. In this paper, we mainly introduce an algorithm to detect the found transmitter in consecutive frames. Experimental results using appropriate images showed the effectiveness of the proposal.
Suboptimal Receiver Using Chaotic Sequences with Biased Values
- S. Arai, Y. Nishio, T. Yamazato
- Proceedings of IEEE Workshop on Nonlinear Circuit Networks (NCN'08), pp. 49-51, Tokushima, Japan
- 2008幎12æ
- We investigate and evaluate a suboptimal receiver using chaotic sequences with biased values. In our previous research, we investigated a differential chaos shift keying (DCSK) using chaotic sequences with biased values purposely and confirmed its better performance. However, our previous study only performed the computer simulation of DCSK using these chaotic sequences. In this study, we focus on the suboptimal receiver and evaluate its performance with chaotic sequences with biased values.
Energy Efficiency of Cooperative MISO Technique in Multi-hop Wireless Sensor Networks
- Z. Huang, T. Yamazato, M. Katayama
- International Conference on Intelligent Sensors, Sensor Networks and Information Processing (ISSNIP), pp. 511-515, Sydney, Australia
- 2008幎12æ
- https://doi.org/10.1109/ISSNIP.2008.4762040
- In this paper, the energy efficiency of cooperative Multiple-Input Single-Output (MISO) technique for a multi-hop wireless sensor network is investigated and compared with other transmission schemes. Firstly, we present different schemes for data transmission of the cluster farther from base station and calculate their energy consumptions. The results show that the optimal transmission scheme varies with the inter-cluster distance in different networks. Then we explore the lifetime of the network and find that it is not always the optimal to employ the multi-hop transmission and the single-hop transmission outperform the multi-hop under a certain distance threshold. In addition, the effects of the transmission bit rate and the required bit error ratio (BER) on the distance threshold are also clarified.
çŽäº€åšæ³¢æ°åå²å€éå€èª¿ãçšããè¡æåç·ã«ãããéç·åœ¢æªã¿è£åæ³ã«ããç¹æ§æ¹å
- é¿è¬åæŽïŒå±±éæ¬ä¹ïŒçå±±æ£æïŒå°å·æ
- é»åæ
å ±éä¿¡åŠäŒè«æèª, vol.J91-B, no.12, pp.1644-1646
- 2008幎12æ
- OFDM 㯠PAPR ãé«ãè¡æéä¿¡ã® TWTA ã«ãã£ãŠéç·åœ¢å¢å¹
æªã¿ãçããïŒãã®ããïŒåž¯åå€èŒ»å°ãæãïŒBERãå£åãããïŒæ¬çš¿ã§ã¯ SLM ã§ PAPR ãæå¶ããããšã§åž¯åå€èŒ»å°ãæå¶ãïŒå埩æªã¿è£åæ³ã«ãã BER ç¹æ§ã®æ¹åãè¡ãæ¹åŒãææ¡ããïŒ
Road-to-Vehicle Visible Light Communication using LED Array and High-Speed Camera
- Takaya YAMAZATO, Shintaro ARAI, Shohei MASE, Tomohiro YENDO, Toshiaki FUJII, Masayuki TANIMOTO and Yoshikatsu KIMURA
- International Workshop on Smart Info-Media Systems in Bangkok (SISB), PS-4, pp.69-74, Swissotel Le Concorde, Bangkok, Thailand
- 2008幎12æ
- In this paper, we present hierarchical coding scheme using LED traffic lights and high-speed camera for Intelligent Transport Systems (ITS) application. If each of LEDs in traffic lights is individually modulated, parallel data transmissions are possible using a camera as a reception device. Such parallel LED-camera channel can be modeled as spatial low-pass filtered channel of which the cut-off frequency varies according to the distance. To overcome, we introduce hierarchical coding scheme based on 2D fast Haar wavelet transform.
Joint Channel Decoding of Spatially and Temporally Correlated Data in Wireless Sensor Networks
- K. Kobayashi, T. Yamazato, H. Okada, M. Katayama
- International Symposium on Information Theory and Its Applications (ISITA), pp.930-934, Auckland, New Zealand
- 2008幎12æ
- https://doi.org/10.1109/ISITA.2008.4895540
- In densely deployed wireless sensor networks, sensor observations are spatially correlated. Furthermore, the nature of physical phenomena constitutes a temporal correlation between transmitted observations of an individual sensor node. In this paper, we propose a joint iterative channel decoding scheme using turbo codes. The proposed decoder exploits the spatial and temporal correlations of two binary data sequences to achieve additional coding gain. Simultaneously exploiting the spatial and temporal correlation, the proposed decoder achieves large performance gain.
Feasible Study of Road-to-Vehicle Communication System Using LED Array and High-Speed Camera
- S. Arai, S. Mase, T. Yamazato, T. Yendo, T. Fujii, M. Tanimoto, Y. Kimura
- 15th World Congress on ITS, New York, USA
- 2008幎11æ
- In this study, we focus attention on the parallel optical wireless communication systems using LED array transmitter and a high-speed camera as the receiver for road-to-vehicle communications in ITS. Previously, we have proposed a hierarchical coding scheme which allocates data to spatial frequency components depending on the priority. This scheme is possible to receive the high priority data even if the receiver is far from the transmitter. However, since vehicles drive on a road in actual road-to-vehicle communications, there are many important works to develop the real-time communication system. For example, it is a difficult to synchronize the timing to release the shutter with the lighting cycle of LEDs, i.e., the sampling of the data. This paper details our road-to-vehicle communication system using the LED array and the high-speed camera and proposes their solutions. Moreover, based on proposed solutions, we perform a driving field trial using the LED array and a vehicle with the high speed camera. As the result, we observe the bit error rate and confirm the reception of the data during the driving.
Investigation of Noncoherent Detection Using Chaotic Sequence with Biased Values
- S. Arai, Y. Nishio, T. Yamazato
- International Workshop on Vision, Communications and Circuits (IWVCC), pp.221-224, Xi'an, China
- 2008幎11æ
- We investigate the chaotic sequence with biased values in chaos-based communication systems. In our previous research, we investigated the the performance of chaos communications using the sequence with biased values purposely. As results, we concluded that the chaotic dynamics affect the performance of chaos communications greatly. However, our previous study only performed the computer simulation the DCSK system using the chaotic sequence with biased values. In this study, we focus on the suboptimal receiver as one of chaos communication systems and observe its performance with the chaotic sequence with biased values.
Energy-aware Protocol for Cluster-based Cooperative Transmission in Wireless Sensor Networks
- K. Takeshima, T. Yamazato, M. Katayama
- International Workshop on Vision, Communications and Circuits (IWVCC), pp.149-152, Xi'an, China
- 2008幎11æ
- In this paper, we look at communication protocol designed for cluster-based cooperative transmission. As it can increase the spatial diversity of wireless channel, cluster-based cooperative transmission is effective not only for reliable transmission but also in reduction of the transmitted power. The overall energy dissipation is, however, governed by a cluster head selection criterion. We show that the conventional random cluster head selection, as in low-energy adaptive clustering hierarchy (LEACH), and the best link quality cluster head selection may not be optimal for cluster-based cooperative transmission. Based on our finding, we propose a new energy-aware protocol for cluster-based cooperative transmission that considers not only the link quality but also the residual energy of sensor nodes. As results, our protocol shows the best in the availability ratio of sensor nodes and outage probability for the number of cluster-to-cluster transmissions.
çžé¢ã®ããè€æ°æ
å ±æºã®ã¿ãŒã笊å·åã»ããè¿ãçµ±ååŸ©å·æ³ã®ç¹æ§è©äŸ¡
- å°æå¥å€ªéïŒå±±éæ¬ä¹ïŒçå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.USN2008-47, pp.51-55, æ²çž
- 2008幎10æ
- åæ£ç¬Šå·åã»çµ±å埩å·ã¯ïŒçžé¢ã®ããè€æ°ã®æ
å ±æºåºåãããããç¬ç«ã«ç¬Šå·åãè¡ãïŒåŸ©å·åŽã§æ
å ±æºã®çžé¢ãå©çšããŠåã
ã®æ
å ±æºåºåã埩å·ãããã®ã§ããïŒéä¿¡ãšãã«ã®ãŒã®åæžã«ç¹ããããšããïŒç¡ç·ã»ã³ãµãããã¯ãŒã¯ãžã®é©çšãçç®ãããŠããïŒçžé¢ã®ãã2ã€ã®æ
å ±æºã«ãããŠïŒã¿ãŒã笊å·ã®ããè¿ã埩å·ãé©çšããçµ±ååŸ©å·æ³ã«ããShannon/Slepian-Wolféçã«è¿ãç¹æ§ãåŸãããããšã瀺ãããŠããïŒæ¬çš¿ã§ã¯ãã®çµ±ååŸ©å·æ³ãæ¡åŒµãïŒçžé¢ã®ãã3ã€ä»¥äžã®è€æ°æ
å ±æºã«ãããŠãShannon/Slepian-Wolféçã«è¿ãç¹æ§ãåŸãããçµ±ååŸ©å·æ³ãææ¡ããïŒåŸ©å·ç¹æ§ãå·Šå³ããèŠå ãšããŠïŒç¬Šå·ã®äžãããšã©ãŒããã¢ç¹æ§ãªãã³ã«åŸ©å·åšã«ãããçžé¢ã®æšå®ã®åœ±é¿ã«çç®ãïŒè€æ°æ
å ±æºã®çžé¢ãå©çšããããšã§åŸããã埩å·ç¹æ§ã«ã€ããŠæ€èšããïŒ
Error Correcting Scheme for Road-to-Vehicle Visible Light Communication using LED Array
- S. Mase, S. Arai, T. Yamazato, T. Yendo, T. Fujii, M. Tanimoto, Y. Kimura
- International IEEE Conference on Intelligent Transportation Systems (ITSC), pp.1113-1117, Beijing, China
- 2008幎10æ
- https://doi.org/10.1109/ITSC.2008.4732586
- In this paper, we propose an improved coding scheme for optical wireless communication systems using a LED array transmitter and a high-speed camera as the receiver on a vehicle. Previously, we have proposed a hierarchical coding scheme which allocated the data to spatial frequency components depending on the priority. In that scheme, the high-priority data can be received even if the receiver was far from the transmitter. We confirmed the advantage of the hierarchical coding scheme, but the bit error performance was not sufficient. In this paper, we divide the data into spatial frequency components, and use error correcting code for each spatial frequency componentsâ data. Experimental evaluation demonstrates the improvement in BER performance. This improvement implies that the system range increased compared to the previous method.
ãã£ãžã¿ã«åè·¯
- ç°æåæïŒåç°ååïŒå±±éæ¬ä¹ïŒé¢æ ¹æåïŒç建éïŒä»²éå·§ïŒç¯ æšåïŒå·äººç¥¥äº
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- 2008幎10æ
空éã»æéçžé¢ã®ããæ
å ±æºã®çµ±ååŸ©å·æ³ã«é¢ããäžæ€èš
- å°æå¥å€ªéïŒå±±éæ¬ä¹ïŒå²¡ç°åïŒçå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒ éä¿¡ãœãµã€ãšãã£å€§äŒ, B-20-6, p.342, å·åŽ
- 2008幎9æ
- åæ£ç¬Šå·åã»çµ±å埩å·ã¯ïŒéä¿¡ãšãã«ã®ãŒã®åæžã«ç¹ããããšããç¡ç·ã»ã³ãµãããã¯ãŒã¯ãžã®é©çšãçç®ãããŠããïŒç¹ã«ïŒç¡ç·ã»ã³ãµãããã¯ãŒã¯ã§ã¯ïŒä»ããŒãã®èŠ³æž¬ããŒã¿ãšã®éã«çãã``空é''çžé¢ã ãã§ãªãïŒåããŒãã«ãããŠä»¥åã®èŠ³æž¬ããŒã¿ãšã®éã«çãã``æé''çžé¢ã®äž¡æ¹ãå«ãã ããŒã¿ãéä¿¡ããŠããããšãç¹åŸŽã§ããïŒå
è¡ç ç©¶ã§ã¯ïŒç©ºéçžé¢ïŒæéçžé¢ã®ããããã«ã€ããŠçžé¢ãå©çšããçµ±ååŸ©å·æ³ãææ¡ãããŠããïŒç©ºéçžé¢ãŸãã¯æéçžé¢ãå©çšããããšã§åŸ©å·ç¹æ§ãåäžã§ããïŒæ¬çš¿ã§ã¯ïŒã¿ãŒã笊å·ã®ããè¿ãåŸ©å·æ³ãæ¡åŒµãïŒæ
å ±æºã®ç©ºéçžé¢ãšæéçžé¢ã®äž¡æ¹ãæ±ããçµ±ååŸ©å·æ³ãææ¡ããïŒç©ºéã»æéçžé¢ãå©çšããããšã§ãã倧ããªåŸ©å·å©åŸãåŸãããããšã瀺ãïŒ
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éä¿¡ã«ãã忣ããŒãéååéä¿¡
- å°æå¥å€ªéïŒä»²å°ŸäºåžïŒå±±éæ¬ä¹ïŒçå±±æ£æ
- 第10å DSPSæè²è
äŒè°, pp.72-73, æ±äº¬
- 2008幎9æ
- ç¡ç·ã»ã³ãµãããã¯ãŒã¯ã§ã¯, å€ãã®ã»ã³ãµããŒãã忣ããŠé
眮ãã, åããŒãã§èŠ³æž¬ãããããŒã¿ã¯ãã¥ãŒãžã§ã³ã»ã³ã¿ãŒã§åéããã. ã»ã³ãµããŒãã¯ãããŠãå°ããé»åãéãããŠãããã, è€éãªåŠçãåºæ¥ãéä¿¡ç¯å²ãçããã®ãšãªã£ãŠãã. ããã§, ããŒãéã®ååéä¿¡ã«ããäŒéè·é¢ã®å»¶é·ãå®çŸãã. ååéä¿¡ã«é¢ããç ç©¶ã¯ïŒè€éã§, å³ãããã£ãªã¢ã»äœçžåææ¡ä»¶ãå¿
èŠãšãããã®ãå€ãïŒæ¬çš¿ã§ã¯, å³ããåææ¡ä»¶ãªãã«, ã·ã³ãã«ãªæ¹åŒã§éæããååéä¿¡ãææ¡ãã. å
·äœçã«ã¯, ãã®åæ£ããŒãéååéä¿¡ã, ã·ã³ãã«ããšã«ããŒãåºæã®ã©ã³ãã äœçžãä¹ç®ããããšã«ãã誀ãèšæ£ç¬Šå·åã®ã¿ã§å®çŸãã. ã·ã³ãã«æ¯ã«åä¿¡æ¯å¹
ãå€åãããããšã§, åŸæ¥æ¹åŒã§çºçãããã±ãããã¹ãç¡ããããšãã§ãã. æ¬ç ç©¶ã§ã¯, 黿³¢æ³ã«ããèŠå¶ããªãéçšã«å
èš±ãäžèŠã§ããïŒéåä¿¡æ©åè·¯ãç°¡æã§ãããšããç¹ãã, LED å¯èŠå
éä¿¡ã«ããçåå®éšãè¡ãïŒãŸãïŒå¯èŠå
ã«ããå®éšã®ãã, éä¿¡ããŠããããŒãæ°ãåããããããšããå©ç¹ãããïŒ
ã³ã°ããã£ãç¡ç·ã«ããéç³éä¿¡ã®ããã®ãã£ãã«æ
å ±ãäžèŠãªå€èª¿æ¹åŒ
- é·çžæœ€ïŒå±±éæ¬ä¹ïŒçå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒ éä¿¡ãœãµã€ãšãã£å€§äŒ, B-17-9, p.452, å·åŽ
- 2008幎9æ
- ã³ã°ããã£ãç¡ç·ãçšããåšæ³¢æ°å
±åå©çšæ¹åŒã®ïŒã€ãšããŠïŒäžæ¬¡(æ¢å)ã»äºæ¬¡(æ°èŠ)ã·ã¹ãã ãåæã«åãåšæ³¢æ°ã§éç³éä¿¡ãè¡ãææ³ãããïŒãã®ææ³ã®å®çŸäŸãšããŠïŒèè
ãã¯ã¹ãã¯ãã«æ¡æ£çãå©çšããïŒç垯åä¿¡å·ã§ããäœçžå€èª¿ãããäžæ¬¡ä¿¡å·ãšäºæ¬¡ä¿¡å·ãïŒäžæ¬¡åä¿¡æ©äžã§åçžãšãªãããã«ããææ³ãææ¡ããŠããïŒ ãããããã§ã¯ïŒäžæ¬¡ã·ã¹ãã ã®ååç¡ãã§ååŸããããšãå°é£ãªãã£ãã«ç¹æ§çã®æ
å ±ãïŒäºæ¬¡ã·ã¹ãã ã®éä¿¡æ©ãå©çšããŠããïŒããã§æ¬çš¿ã§ã¯ïŒäžèšã®ãã£ãã«ç¹æ§ãäžèŠãªéç³éä¿¡æ¹åŒãææ¡ãïŒæ°å€äŸã«ããäžæ¬¡ã·ã¹ãã ã®èª€ãçç¹æ§ã®å£åç¡ãã«ïŒäºæ¬¡ã·ã¹ãã ä¿¡å·ãéç³å¯èœã§ããããšã瀺ãïŒ
A New SC/MMSE Turbo Equalization for MC-CDMA to use in Inter-Vehicle Communication
- N. Hiraiwa, A. Sakata, T. Yamazato, M. Katayama
- IEEE Vehicular Technology Conference (VTC-Fall), Calgary, Canada
- 2008幎9æ
- https://doi.org/10.1109/VETECF.2008.257
- In this paper, we propose a new SC/MMSE Turbo equalizer for MC-CDMA to use in inter-vehicle communication (IVC). We modify the weight of the MMSE filter of SC/MMSE Turbo equalizer so that it can combat with frequency-selective fading in highly mobile IVC environment and also can mitigate the effect of multiple access interferences (MAI). As results, we show that better throughput is obtained by the proposed SC/MMSE equalization than the conventional one. The average reception range can be up to 70 [m] and the signals from 16 surrounding cars can be received. While for the conventional scheme, only three signals from the nearest cars are achieved.
Error-Correcting Method Based on Chaotic Dynamics for Noncoherent Chaos Communications
- S. Arai, Y. Nishio, T. Yamazato
- International Symposium on Nonlinear Theory and its Applications (NOLTA), pp. 652-655, Budapest, Republic of Hungary
- 2008幎9æ
- This paper proposes the error-correcting method based on the chaotic dynamics for noncoherent chaos communications. We generate successive chaotic sequences from the identical chaotic map. And for the next sequence we set the initial value to the end value of the former sequence. By such way we can create the successive chaotic sequences having the same chaotic dynamics. This feature gives the receiver additional information to correctly recover the received noisy signal. Therefore, by analyzing the chaotic dynamics at the receiver, it is possible to improve the error performance. In other words, error performance of the receiver can be improved by the utilization of the suboptimal receiver with the analysis of chaotic dynamics of the successive received sequence. As results of computer simulations, we confirm about 3 dB gain in BER performance compared to the conventional suboptimal receiver.
éçœè²ã»åšæå®åžžéé³ã䌎ãé»åç·éä¿¡ã®ããã®é©å¿å€èª¿ãšé»åå²ãåœãŠ
- 柀ç°çŽä¹, 山鿬ä¹, çå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒ åºç€ã»å¢çãœãµã€ãšãã£å€§äŒ, A-5-2, p.89, å·åŽ
- 2008幎9æ
- é»åç·ã«æ¥ç¶ããã黿°æ©åšãäž»å ãšããé»åç·éä¿¡ã®éé³ã¯ïŒéçœè²ã§ããïŒãŸã黿ºé»å§ã«åæããåšæå®åžžæ§ãæã€ïŒãã®éé³ã®æ§è³ªã«çç®ãïŒåä¿¡æ©åŽã®éé³ã®åšæå¹³åé»åã«åºã¥ãé©å¿å€èª¿ãšåæã«é»åå²ãåœãŠãè¡ãæ¹åŒãææ¡ããïŒæ¬çš¿ã§ã¯ïŒéä¿¡æ©ãšåä¿¡æ©ã§ã®é»åç·ã®éé³ã®åšæå¹³åé»åã®çžé¢ãå©çšããé©å¿å€èª¿ã«é»åå²ãåœãŠãå ããææ³ãææ¡ãïŒBERç¹æ§ãæ¹åã§ããããšã瀺ããïŒ
CDMA slotted ALOHA System with Successive Interference Cancellation for Inter-Vehicle Communications
- A. Sakata, T. Yamazato, H. Okada, M. Katayama
- IEEE International Symposium on Spread Spectrum Techniques and Applications (ISSSTA), pp.188-193, Bologna,Italy
- 2008幎8æ
- https://doi.org/10.1109/ISSSTA.2008.40
- This paper compares the throughput performance of orthogonal frequency division multiple access (OFDM) and multicarrier CDMA (MC-CDMA) in inter-vehicle communications (IVC).In particular, we compare the throughputs in a situation where hidden terminals are no longer negligible. We encounter the situation in an intersection where two or more cars are crossing by. Due to the hidden terminal degradation, poor throughput performance is obtained with OFDM scheme. On the other hand, MC-CDMA has a resistance to the hidden terminals as it can support simultaneous packets. However, the transmission data rate is much slow because of the spreading. Thus the total throughput may not be as high as the OFDM. As results, we show that throughput of the OFDM is better than the MC-CDMA in a low traffic region. We found that the OFDM can communicate only with the nearest car. On the contrary, when the traffic is high, the MC-CDMA shows better throughput than the OFDM. In addition, we show that many packets can be received simultaneously in MC-CDMA. These results lead to the conclusion that when we want high-speed communication to a few cars, the OFDM is a good candidate. And when low speed but simultaneous communication with many surrounding cars is our desire, then the MC-CDMA is our choice. As MC-CDMA has a compatibility with an OFDM by setting a spreading factor to one, MC-CDMA system may be the preferable choice for IVC.
èªåè»çšè¿è·é¢ã¬ãŒããããã¯ãŒã¯ã®ããã®è¶
鳿³¢ã¢ã¬ã€ãšããã¿
- 矜å€éè£ä¹ïŒå±±éæ¬ä¹ïŒçå±±æ£æ
- èªåè»æè¡, vol.62, no.7, pp.29-34
- 2008幎7æ
- We consider radar network systems using multiple ultrasonic radars for parking assistance. Our radar network has an ultrasonic array emitter and multiple sensors. The ultrasonic array emitter is composed of multiple ultrasonic emitters and can emit signals to the side area which is the desired monitoring area of parking aid. Target positions are estimated by the data processing form multiple ultrasonic sensors which are set at distributed points of the front bumper. In this paper we especially describe our proposed array emitter.
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- 山鿬ä¹ïŒèäºäŒžå€ªéïŒéç¬ç¥¥å¹³ïŒåéç¥åïŒè€äºä¿åœ°ïŒè°·æ¬æ£å¹žïŒæšæå¥œå
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.108, no.163, SIP2008-76, pp.47-52, åºå³¶å€§åŠ
- 2008幎7æ
- æ¬ç ç©¶ã§ã¯ïŒLED ã¢ã¬ã€ãšé«é床ã«ã¡ã©ãçšããè·¯è»éå¯èŠå
éä¿¡ã«è¿°ã¹ãïŒLED ã¢ã¬ã€ãšé«é床ã«ã¡ã©ãçšããããšã§ïŒåã
ã® LED ãç¬ç«ã«å€èª¿ãããå Žåã§ãã«ã¡ã©ãçšããããšã§ïŒããããåå¥ã«åä¿¡ã§ããïŒããããïŒLED ã®æ°ã ã䞊åã«ããŒã¿äŒéãå¯èœã«ãªãïŒããããªããïŒLED éä¿¡æ©ãšåä¿¡ã«ã¡ã©éã®è·é¢ãé·ãå ŽåïŒåä¿¡ç»åã«ããããã¯ã»ã«æ°ã®æžå°ãçŠç¹ãããªã©ã«ãã£ãŠ LED ã®ç¹ç¯ãã¿ãŒã³ãå£åããŠåä¿¡ãããïŒèè
çã¯ïŒä»¥äžã®åé¡ã«å¯ŸåŠã§ããéå±€ç笊å·åæ¹åŒãææ¡ããŠããïŒæ¢ã«éæ¢ç°å¢ã§ã®æå¹æ§ã確èªããŠã ãïŒæ¬çš¿ã§ã¯ïŒæšå¹ŽåºŠå®æœããïŒç§»åç°å¢ã§ã®åä¿¡ç¹æ§ã«ã€ããŠç޹ä»ããïŒ
éå±€ç笊å·åãçšããè·¯è»éå¯èŠå
éä¿¡ã®ããã¹ãæ§åäž
- éç¬ç¥¥å¹³, èäºäŒžå€ªé, 山鿬ä¹, åéæºå, è€äºä¿åœ°, è°·æ¬æ£å¹ž, æšæå¥œå
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol. ITS2008-11, pp. 19-24, åå€å±
- 2008幎7æ
- æ¬çš¿ã§ã¯LEDä¿¡å·æ©ãšè»èŒé«é床ã«ã¡ã©ãçšããå
空ééä¿¡ã«ããã誀ãçã®æ¹åæ¹æ³ãææ¡ãã. åä¿¡æ©ãã«ã¡ã©ãšããå
空ééä¿¡ã§ã¯, é ãããåä¿¡ãããšç»åã®é«åšæ³¢æåã倱ãã, äœåšæ³¢æåãå€ãæ®ã. ãã®ããšã«å¯ŸåŠãããã, éå±€ç笊å·åæ¹åŒã§ã¯, äœåšæ³¢æåã«åªå
床ã®é«ãããŒã¿ãé
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床ã®é«ãããŒã¿ã»ã©é ãããåä¿¡ã§ããããšã¯ç¢ºèªåºæ¥ãã, 誀ãçç¹æ§ã¯ãŸã ååã§ãªãã£ã. ããã§æ¬çš¿ã§ã¯ããŒã¿ãåšæ³¢æ°æåã«åã, ãã®åšæ³¢æ°æåããšã«èª€ãèšæ£ç¬Šå·åãã. ãã®çµæ, 誀ãçç¹æ§ãæ¹åã, ããé ãããåä¿¡ã§ããããšã瀺ã.
A Route Establishment Scheme for Multi-route Coding in Multihop Cellular Networks
- H. Okada, H. Imai, T. Yamazato, M. Katayama, K. Mase
- Academy Publisher Journal of Netowkrs, vol.3, no.7, pp.34-40
- 2008幎7æ
- Since the network topology in multihop cellular networks is flexible, multiple routes from a user station to a base station can be established. To reduce packet reception errors of wireless links, a multi-route coding scheme was proposed. An important issue of the multi-route coding is to develop an efficient route establishment scheme. In this paper, we propose a route establishment scheme for multi-route coding in multihop cellular networks. Our proposed scheme consists of a route selection method based on the bit error rate of each wireless link and a hybrid-type multiple-tree routing protocol. We evaluate the performance of our proposed scheme by a computer simulation and show the resulting improvement in the packet error.
å®å
šéè»¢æ¯æŽã®ããã®è»è»ééä¿¡ã«ãããOFDMãšMC-CDMAã®ç¹æ§è©äŸ¡
- åç°ç¯€åïŒå±±éæ¬ä¹ïŒå²¡ç°åïŒçå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.ITS2008-8, pp.1-6, åå€å±
- 2008幎7æ
- æ¬çš¿ã§ã¯, å®å
šéè»¢æ¯æŽã®ããã®è»è»ééä¿¡ã«ãããŠOFDMãšMC-CDMA, ããã³MC-CDMAãããŒã¹ãšããMC-OFDMAã®ãã±ããåä¿¡æå確çç¹æ§ãæ€èšãã. ç¹ã«, è»äž¡ãå¯éãé ã端æ«åé¡ãç¡èŠã§ããªããããªç¶æ³ã«ãããŠæ¯èŒãã. 亀差ç¹ã®ããã«èŠéãã«å¶éãããå Žåã§ã¯, ç¹ã«é ã端æ«åé¡ãçºçãããã. æã
ã¯ç©çå±€ã«çç®ã, é ã端æ«åé¡ã«å¯ŸããŠèæ§ã®ããCDMAãslotted ALOHAæ¹åŒãææ¡ããŠãã. æ¬çš¿ã§ã¯, æ¡æ£çããã£ãªã¢ã®å²ãåœãŠæ¹ã«ãã£ãŠ, ç¹æ§ãã©ã®ããã«å€åããã®ãã調ã¹ã. ã·ãã¥ã¬ãŒã·ã§ã³è©äŸ¡çµæãã, MC-OFDMAã®æ¹ãOFDMãããã±ããåä¿¡æå確çãé«ãããšã瀺ã.
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å ±æºã®åæ£ç¬Šå·åã»çµ±ååŸ©å·æ³ã®EXITè§£æ
- å°æå¥å€ªéïŒå±±éæ¬ä¹ïŒçå±±æ£æ
- 第4åç¡ç·åæ£ãããã¯ãŒã¯ã«é¢ããã¯ãŒã¯ã·ã§ãã, åå€å±
- 2008幎6æ
æ¢åãŠãŒã¶ã«éç³ããŠéä¿¡ãè¡ãã³ã°ããã£ãç¡ç·ã·ã¹ãã ã®ããã®å€èª¿æ¹åŒ
- é·çžæœ€ïŒå±±éæ¬ä¹ïŒçå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.SR2008-2, pp.5-10, 暪æµ
- 2008幎5æ
- åšæ³¢æ°åž¯åã®æå¹å©çšã®ããã«ïŒè€æ°ã·ã¹ãã ã®åæå©çšãèããïŒãã®éïŒæ¢åã·ã¹ãã ïŒäžæ¬¡ã·ã¹ãã ïŒã«ã¯ 倿Žãå ããããšç¡ãïŒãŸãæ°èŠã·ã¹ãã ïŒäºæ¬¡ã·ã¹ãã ïŒãäžæ¬¡ã·ã¹ãã ã«åŠšå®³ãäžããããšç¡ãïŒäºæ¬¡ã·ã¹ãã ã®éä¿¡ãå®çŸãããïŒããã§æ¬çš¿ã§ã¯ã³ã°ããã£ãç¡ç·æè¡ã«ããïŒäºæ¬¡ã·ã¹ãã ãäžæ¬¡ã·ã¹ãã ã«é¢ããæ
å ±ãååŸãïŒäžæ¬¡ã·ã¹ãã ãšåäžåšæ³¢æ°ã§éç³éä¿¡ãå®çŸããããã®äºæ¬¡ã·ã¹ãã ã®ããã®ä¿¡å·æ¹åŒãææ¡ããïŒããã«ïŒäž¡ã·ã¹ãã ã®åä¿¡æ©ã®ã·ã³ãã«èª€ãçç¹æ§ãè§£æçã«å°åºãïŒäžæ¬¡ã·ã¹ãã ã®èª€ãçãæªåããããšãªãïŒäºæ¬¡ã·ã¹ãã ãäžæ¬¡ã·ã¹ãã ãšåçã®èª€ãçã§éä¿¡ããããšãå¯èœã§ããããšã瀺ãïŒ
é«ä¿¡é Œç¡ç·å¶åŸ¡å®çŸã®ããã®è€æ°éåä¿¡ã¢ã³ãããšè€æ°äžç¶åšãçšãã空éãã€ããŒã·ãææ³
- æç°è¯ä»ïŒå²¡ç°åïŒå±±éæ¬ä¹ïŒçå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒè«æèª, vol.J91-B, no.5, pp.585-594
- 2008幎5æ
- å·¥å Žã®ç£æ¥æ©åšãªã©ã«å¯ŸããŠä¿¡é Œæ§ã®é«ãç¡ç·å¶åŸ¡ãå®çŸããããã®ç¡ç·éä¿¡ã·ã¹ãã ã®æ€èšãè¡ãïŒå®€å
ç°å¢ã«ãããç¡ç·éä¿¡ã·ã¹ãã ã®ç¹æ§å£åã®äž»ãªèŠå ãšããŠïŒãã§ãŒãžã³ã°ãšã·ã£ããŠã€ã³ã°ãããïŒãããã®åœ±é¿ãäœæžããããïŒç©ºéãã€ãã·ããé©çšããïŒãã®å®çŸæ¹æ³ãšããŠïŒæ¬è«æã§ã¯ïŒè€æ°éåä¿¡ã¢ã³ãããšè€æ°äžç¶åšãçšããææ³ãææ¡ããïŒææ¡ææ³ã¯äžç¶åšçŸ€--åä¿¡æ©éã§STBCãé©çšããïŒäžè¬ã«åäžç¶åšãç°ãªããã©ã³ããéžæããããã«ã¯äžç¶åšéã§æ
å ±ã亀æããå¿
èŠãããïŒãããè¡ããªãå ŽåïŒéè€ãããã©ã³ããéžæããïŒãã€ãã·ãå©åŸãäœäžããïŒããã«å¯Ÿãæ¬è«æã§ææ¡ããææ³ã§ã¯ïŒãã©ã³ããéè€ãã確çãäœæžããææ³ãææ¡ã ãïŒããã«ããïŒãã€ãã·ãå©åŸã®å£åãæå§ããããšãå¯èœã§ããïŒæ°å€äŸã§ã¯ïŒãã©ã³ãéã®çžé¢ãèæ
®ã«å
¥ããŠå¹³åãã¬ãŒã 誀ãçãšãã¬ãŒã 誀ãçã®outage確çãè©äŸ¡ãïŒææ¡ææ³ã«ãããäžç¶åšå°æ°ãšãã€ãã·ãå©åŸã®é¢ä¿ã«ã€ããŠæããã«ããïŒ
Measurement of Narrowband Channel Characteristics in Single-Phase Three-Wire Indoor Power-Line Channels
- Y. Sugiura, T. Yamazato, M. Katayama
- IEEE International Symposium on Power Line Communications and Its Applications (ISPLC), pp.18-23, Jeju,Korea
- 2008幎4æ
- https://doi.org/10.1109/ISPLC.2008.4510392
- This manuscript reports the measurement results of narrowband signal propagation of PLC channels. In Japan, in-house wiring is single-phase three-wire, and each branch between an outlet of 100V and the panel board is connected to one of two live conductors and the neutral. Thus a pair of outlets can be classified into three types: connected to different live conductors, connected to the same live conductors by different branches from the panel board, and on the same branch to the same live conductor. It is confirmed that the results of the measurements can be classified by these three types of paths. The results show that frequency responses of narrowband PLC channels are relatively smooth, compared with that of wideband PLC. It is also found that propagation loss in lower frequency range is larger than in higher frequency range. The time independence of narrowband PLC channels are confirmed when no electric appliance is connected to the same live conductor.
çžé¢ã®ããè€æ°æ
å ±æºã®ã¿ãŒã笊å·åã»ããè¿ãçµ±ååŸ©å·æ³
- å°æå¥å€ªéïŒå±±éæ¬ä¹ïŒçå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, B-20-4, p.545, åä¹å·
- 2008幎3æ
- åæ£ç¬Šå·åã»çµ±å埩å·ã¯ïŒçžé¢ã®ããè€æ°ã®æ
å ±æºãããããç¬ç«ïŒãŸãã¯åŸå±ïŒã«ç¬Šå·åãè¡ãïŒåŸ©å·åŽã§çžé¢ãå©çšããŠåã
ã®æ
å ±æºã埩å·ãããã®ã§ããïŒæ
å ±æºã®å§çž®ã¯éä¿¡ãšãã«ã®ãŒã®åæžã«ç¹ããããšããïŒã»ã³ãµãããã¯ãŒã¯ãžã®é©çšãçç®ãããŠããïŒçžé¢ã®ãã2ã€ã®æ
å ±æºã«ãããŠïŒã¿ãŒã笊å·ã®ããè¿ãåŸ©å·æ³ãé©çšããããšã§Shannon/Slepian-Wolféçã«è¿ãç¹æ§ãåŸãããããšã瀺ãããŠããïŒæ¬çš¿ã§ã¯ã¿ãŒã笊å·ã®ããè¿ãåŸ©å·æ³ãæ¡åŒµãïŒçžé¢ã®ããè€æ°ïŒ3ã€ä»¥äžïŒã®æ
å ±æºã«ãããŠããäœã誀ãçãéæã§ããããè¿ãçµ±ååŸ©å·æ³ãææ¡ããïŒ
éçœè²ã»åšæå®åžžéé³ã䌎ãé»åç·éä¿¡ã®ããã®é©å¿å€èª¿
- 柀ç°çŽä¹, 山鿬ä¹, çå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, A-5-18, p.145, åä¹å·
- 2008幎3æ
- é»åç·ã«æ¥ç¶ããã黿°æ©åšãäž»å ãšããé»åç·éä¿¡ã®éé³ã¯ïŒéçœè²ã§ããïŒãŸã黿ºé»å§ã«åæããåšæå®åžžæ§ãæã€ïŒãã®éé³ã®æ§è³ªã«çç®ãïŒåä¿¡æ©åŽã®éé³ã®åšæå¹³åé»åã«åºã¥ãïŒé©å¿å€èª¿ã®å€èª¿æ¹åŒã®å²ãåœãŠãè¡ãæ¹åŒãææ¡ããïŒæ¬çš¿ã§ã¯ïŒéä¿¡æ©ãšåä¿¡æ©ã§ã®é»åç·ã®éé³ã®åšæå¹³åé»åã®çžé¢ãå©çšããé©å¿å€èª¿ææ³ã®ææ¡ãè¡ãïŒBERç¹æ§ãæ¹åã§ããããšã瀺ããïŒ
Autonomous Collision-less Slot Assignment Algorithm for Wireless Sensor Networks
- R. Chandradasa, T. Yamazato, M. Katayama
- IEICE General Conference, B-20-28, p.569, Kyushu, Japan
- 2008幎3æ
- Traditional MAC protocols for Sensor Networks are mostly based on random access methods, which cause message collision and energy loss. Several TDMA based methods have been proposed to prevent signal collision with the help of a base station. We propose an algorithm which assigns time slots to sensor nodes without the help of a base station and realizes time-slot reuse.
OFDMAã»ã«ã©ã·ã¹ãã ã«ãããã»ã«ç«¯ç«¯æ«ã®äŒéå¹çæ¹åã®ããã®ãã£ãªã¢å²åœ
- äŒæšé
, 山鿬ä¹, çå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, B-5-44, p.430, åä¹å·
- 2008幎3æ
- 次äžä»£ã»ã«ã©ã·ã¹ãã äžããªã³ã¯ã«ãããéä¿¡æ¹åŒãšããŠOFDMAæ¹åŒã泚ç®ãããŠãããOFDMAæ¹åŒã§ã¯åšæ³¢æ°å©çšå¹çã®åäžãªã©ã®çç±ããå
šãŠã®ã»ã«ã§åäžåšæ³¢æ°ã®äœ¿çšãæ€èšãããŠãããããã, ã»ã«ç«¯ã®ãããªå Žæã§ã¯é£æ¥ã»ã«å¹²æžã«ããåèº«ç¹æ§ãæªããªããšããåé¡ãçºçãããæ¬çš¿ã§ã¯é£æ¥ã»ã«å¹²æžãäœæžããããã«ãã£ãªã¢å²åœãè¡ãããšã§ã»ã«ç«¯ç«¯æ«ã®äŒéå¹çãæ¹åããææ³ãææ¡ãããææ¡ææ³ã§ã¯ïŒå²ãåœãŠããã£ãªã¢ãåºå°å±ããšã«å€æŽããã€ã³ã¿ãªãŒããšéä¿¡è·¯çååšã®éã¿ã倿Žããããšã§ã»ã«ç«¯ç«¯æ«ã®äŒéå¹çãæ¹åããã
MC-CDMAãçšããè»è»ééä¿¡æ¹åŒã«ããã >SC/MMSEåã¿ãŒãçåãšMMSEçåã®ç¹æ§æ¯èŒ
- 平岩士æ, åç°ç¯€å, 山鿬ä¹, çå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, B-5-65, p.451, åä¹å·
- 2008幎3æ
- è»è»ééä¿¡ã¯ïŒè»äž¡éã®éä¿¡ã«ããå®å
šæ§ãå¹çæ§ã®åäžãç®çãšããŠããïŒMC-CDMAãçšãã瀟è»ééä¿¡æ¹åŒã§ã¯é ã端æ«åé¡ã«å¯ŸåŠãå¯èœã§ïŒåæã«å€æ°ã®è»äž¡ãšéä¿¡ãå¯èœã§ããïŒè»è»ééä¿¡ã§ã¯ïŒè»äž¡ãé«éã«ç§»åãããã笊å·éå¹²æžããã£ãªã¢éå¹²æžã®åœ±é¿ã倧ãããšèããããïŒã¿ãŒãçåã¯ç¹°ãè¿ãåŠçãè¡ãããïŒãã®ãããªç¶æ³ã§åé¡ãšãªãæ®çå¹²æžæåãæå§ããããšãå¯èœã§ããïŒæ¬çš¿ã§ã¯ïŒMC-CDMA ãçšããè»è»ééä¿¡ã«å¯ŸããŠïŒSC/MMSE å(Soft Interference Canceller followed byMMSE fillter) ã¿ãŒãçåãé©å¿ããïŒMMSE çåãšã¹ã«ãŒãããç¹æ§ã®æ¯èŒãè¡ãïŒ
ãã«ãã»ã«OFDMA s-ALOHAã·ã¹ãã ã®äžããªã³ã¯ãžã®Fractional Frequency ReuseãšFast Retrial Algorithmã®é©çš
- æšæå幞, 山鿬ä¹, çå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, B-5-47, p.433, åä¹å·
- 2008幎3æ
- ã»ã«ã©ç¡ç·ã·ã¹ãã ã®äžããªã³ã¯ã«ãããã©ã³ãã ã¢ã¯ã»ã¹æ¹åŒãšããŠ, OFDMAã®åãµããã£ãã«ã«slotted-ALOHA ãé©çšããæ¹åŒãææ¡ãããŠãã. 以äž, ãã®æ¹åŒãOFDMA s-ALOHA ãšåŒã¶. ããã, ãã®ææ³ã§ã¯ãã«ãã»ã«ã«ãããä»ã»ã«ããã®å¹²æžã«ãã, ç¹ã«é«è² è·æã«ãããŠã¹ã«ãŒãããã倧ããäœäžããŠããŸã. æ¬ç ç©¶ã§ã¯, OFDMA s-ALOHA ã«Fractional FrequencyReuse(FFR)ãé©çšããããšã§ãã«ãã»ã«ç°å¢äžã«ãããå¹²æžã®åœ±é¿ã®äœæžãå³ã. ããã«FFR ã«å ãFastRetrial Algorithm(FRA)ãåæã«çšããããšã§, äœè² è·æã«ãããã¹ã«ãŒãããã®åäžãå³ã.
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é»åç·éä¿¡è·¯ã«ãããç垯åä¿¡å·äŒæ¬ç¹æ§ã®æå€æ§
- ææµŠäœ³æ, 山鿬ä¹, çå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, A-5-17, p.144, åä¹å·
- 2008幎3æ
- é»åç·éä¿¡ã«ãããŠãã£ãã«ã®æ§è³ªã¯ç¹ç°ã§ãã, ããã«åŸã£ãèšèšãéèŠã§ããïŒåºåž¯åã®äŒéè·¯ç¹æ§ã¯ïŒå€ãã®æž¬å®äŸããã, 黿ºé»å§ã®ååšæã«åæããŠäŒæ¬ç¹æ§ãæéå€åããããšçãç¥ãããŠãã. ããã, ç垯åã®äŒéç¹æ§ã«é¢ããå ±åã¯å°ãªã, ç¹ã«é£ç¶æé芳枬ã«ããæå€æ§ã¯æ®ã©ç¥ãããŠããªãïŒããã§æ¬çš¿ã§ã¯, ç垯åä¿¡å·äŒæ¬ç¹æ§ã®æå€æ§ã枬å®ãã. 枬å®ãã, ç垯åã§ãåºåž¯åãšåæ§ã«, äŒæ¬æå€±ãšäœçžç¹æ§ã¯æå€æ§ã瀺ããšããããšãæããã«ãã.
è€æ°ã®åããæã€ã«ãªã¹ç³»åãçšãããã³ã³ããŒã¬ã³ãéä¿¡ã·ã¹ãã
- èäºäŒžå€ªé, è¥¿å°Ÿè³æ, 山鿬ä¹
- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, A-2-35, p.74, çŠå²¡
- 2008幎3æ
- è¿å¹ŽïŒã«ãªã¹ãå©çšãããã£ãžã¿ã«éä¿¡ã·ã¹ãã ã®ç ç©¶ãçãã«è¡ãããŠããïŒç¹ã«ïŒéä¿¡æ©ãšåä¿¡æ©ã§åŸ©èª¿ã«äœ¿çšããç³»åãå
±æããªããã³ã³ããŒã¬ã³ãéä¿¡ã·ã¹ãã ãæ³šç®ãããŠããïŒãããŸã§ã®ç ç©¶ã§ïŒç§éã¯ã«ãªã¹ç³»åã®å€ã«åããæãããŠã«ãªã¹éä¿¡ã«å¿çšããããšã詊ã¿ãïŒãã®çµæïŒåããæãããäºã§èªå·±çžé¢ã®é«ãç³»åã容æã«çæããããšãã§ãïŒåãã®ãªãç³»åãšæ¯èŒããŠããã誀ãç(BER) ã®åäžã確èªã§ããïŒããããªããïŒåããæ¹ã«ãã£ãŠã¯çžé¢ãäœãïŒå Žåã«ãã£ãŠã¯å€§ããã®äŒŒéã£ãå€ã亀äºã«åºçŸããŠããŸãïŒåãã®ãã©ã³ã¹ãéèŠãªèª²é¡ã§ãã£ãïŒããã§ïŒæ¬ç ç©¶ã§ã¯ã«ãªã¹ååã®åŸããå¢ãããŠã«ãªã¹ç³»åã®å€ã®åããå¢å ããïŒäŒŒéã£ãå€ã亀äºã«åºçŸããããšãæãã€ã€çžé¢ç¹æ§ã®åªããç³»åã®çæã詊ã¿ã
è»è»ééä¿¡ã®ããã®å¹²æžé€å»æ³ãçšããCDMA slotted ALOHAæ¹åŒ
- åç°ç¯€åã山鿬ä¹ã岡ç°åãçå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒ ç·å倧äŒ, A-17-12, p.323, åä¹å·
- 2008幎3æ
- è€æ°ã®è»äž¡ã亀差ç¹ã«ãããŠéä¿¡ãè¡ãæãé ã端æ«åé¡ãé »ç¹ã«çããããã®ããCSMAã¯æ£ããåäœããªããããã§ãè»è»ééä¿¡ã«ãããŠãé ã端æ«åé¡ã«å¯ŸããŠèæ§ã®ããCDMA slotted ALOHAæ¹åŒãææ¡ããŠãããCDMAã·ã¹ãã ã®æ§èœã決ããéèŠãªäžã€ã®èŠå ãšããŠãå€å
æ¥ç¶å¹²æžããããè€æ°ã®è»äž¡ãšåæéä¿¡ãããããä»è»äž¡ã®ä¿¡å·ãå¹²æžãšãªãå
šäœã®ã¹ã«ãŒããããäœäžããŠããŸããããã§ãæ¬çš¿ã§ã¯å€å
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LEDã¢ã¬ã€ãšé«é床ã«ã¡ã©ãçšããéå±€ç笊å·åã®è·¯è»éå¯èŠå
éä¿¡å®éš
- èäºäŒžå€ªé, éç¬ç¥¥å¹³, 山鿬ä¹, åéç¥å, è€äºä¿åœ°, è°·æ¬æ£å¹ž, æšæå¥œå
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.ITS2007-61, pp.151-156, åæµ·é
- 2008幎2æ
- ç§éã¯ïŒéä¿¡æ©ã«LED ã䞊åã«äžŠã¹ãã¢ã¬ã€è£
眮ãšåä¿¡æ©ã«é«é床ã«ã¡ã©ãçšãã䞊åå
空ééä¿¡ã«çç®ããŠããïŒITS ã«ãããè·¯è»ééä¿¡ãžã®å¿çšãæ€èšããŠããïŒãããŸã§ïŒã«ã¡ã©ãçšããããšã§çããïŒéåä¿¡æ©ã®è·é¢ã«ãããã£ãã«ç¹æ§ãç»åã®è§£å床ãå€åãã åé¡ã«å¯ŸããŠïŒããŒã¿ã«åªå
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床ã®é«ãããŒã¿ã®ååŸãå¯èœãšããéå±€ç笊å·åãææ¡ãããïŒããããªããïŒå®éã«ã¯è»äž¡ã¯åãããïŒã«ã¡ã©ã®ã·ã£ãã¿ãŒééãšLED ã®ç¹ç¯ééãåæãããããšã¯å°é£ã§ããïŒããŒã¿ã®ãµã³ããªã³ã°ãéåžžã«éèŠãªèª²é¡ã§ããïŒããã§ïŒæ¬çš¿ã§ã¯èµ°è¡æã«é©ãããµã³ããªã³ã°ææ³ãææ¡ãïŒé«é床ã«ã¡ã©ãè»ã«èšçœ®ããŠè·¯è»ééä¿¡ã®èµ°è¡å®éšãè¡ãïŒãããŠïŒãªãã©ã€ã³åŠçã§ã®ããŒã¿è§£æãè¡ãïŒæå¹æ§ã確èªãããšãšãã«ïŒèµ°è¡æã®éä¿¡ã·ã¹ãã ã®èšèšã®ããã®èª²é¡ãæ¢ãïŒ
Performance Improvement ofDownlink MC-CDMA Cellular Systemwith an Intermittent Transmission
- M. Fushiki, T. Yamazato, M. Katayama
- IEEE Radio and Wireless Symposium, pp.275-278, Orlando
- 2008幎1æ
- https://doi.org/10.1109/RWS.2008.4463482
- Throughput performance of MC-CDMA systems depends on the success in managing interference arising from intercell transmission. In this paper, we propose a new intercell interference mitigation scheme for downlink MC-CDMA scheme. In the proposed scheme, a base station transmits downlink signals intermittently to mobile terminals at the edge of cell. The intercell interference can be seen as a partial interference depend upon the on and off period of the adjacent downlink signals. So it is possible for the channel equalizer to suppress this partial intercell interference by setting the weight changes in accordance with the intercell interference. As results, the frame error rate of the proposed scheme is always better than that of the conventional scheme and good throughput performance is achieved especially when the traffic is high.
çžé¢ã®ããæ
å ±æºã®åæ£ç¬Šå·åã»çµ±ååŸ©å·æ³ã®EXITè§£æã«é¢ããäžæ€èš
- å°æå¥å€ªéïŒå±±éæ¬ä¹ïŒçå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.RCS2007-125, pp.79-83, 倧å
- 2007幎12æ
- EXITè§£æã§ã¯ïŒé£æ¥ç¬Šå·ã«ãããèŠçŽ åŸ©å·åšéã®äºåæ
å ±ãšå€éšæ
å ±ã®å
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å ±æºã«ãããŠïŒã¿ãŒã笊å·ãããŒã¹ãšããããè¿ãçµ±ååŸ©å·æ³ãææ¡ãïŒãã®EXITè§£æææ³ã«ã€ããŠæ€èšããïŒ
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- 2007幎12æ
Improvement of Error Performance for Noncoherent Chaos Communications
- S. Arai, Y. Nishio, T. Yamazato
- Proceedings of IEEE Workshop on Nonlinear Circuit Networks (NCN'07), pp. 54-56, Tokushima, Japan
- 2007幎12æ
- This paper proposes the error-correcting for noncoherent chaos communications. To improve the error performance, we focus attention on the successive chaotic sequence based on the chaotic dynamics. Concretely, error performance of a noncoherent receiver improves by analyzing the chaotic dynamics of the successive received sequence. As results of computer simulations, we confirm about 3 dB gain in BER performance compared to the conventional suboptimal receiver.
ç¡ç·å¶åŸ¡ã®é«ä¿¡é Œåã®ããã®é»æ³¢äŒæ¬ç¹æ§ã®æž¬å®
- é è€åº·åž, 山鿬ä¹, çå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.RCS2007-97, pp.1-6, æ±äº¬
- 2007幎11æ
- å·¥å Žå
çã«ãããç£æ¥æ©åšã®å¶åŸ¡ãç¡ç·åããããã®åºç€è³æãšãããã, ç¡ç·LANçãååšãã2.4GHz垯ã«ãããŠ, è€æ°ã®äŒæ¬è·¯ã«ã€ããŠåæã«é£ç¶(5ç§)åºåž¯å(23MHz)ã®æž¬å®ãè¡ããç³»ãæ§ç¯ã,枬å®å®éšãè¡ã£ã. ããã«ããïŒåæã«æž¬å®ãã2ã€ã®å®€å
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- å·å£æç, 岡ç°å, 山鿬ä¹, çå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒè«æèªãvol.J90-A, no.11, pp 851-860
- 2007幎11æ
- æ¬è«æã§ã¯ïŒåçžäžç·åŒã§é
ç·ãããé»åç·ã®ãããã¯ãŒã¯ã«ãããŠïŒç°ãªãç®æã®ã³ã³ã» ã³ãã§æž¬å®ãããéé³ã®çžé¢ãè°è«ããïŒæž¬å®çµæããïŒ2ã€ã®ç°ãªãã³ã³ã» ã³ãã®é
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OFDM for satellite communications
- T. Yamazato, A. Ogawa
- Technical Report of IEICE, vol. 107, no. 299, SAT2007-29, pp. 59-64, Okinawa, Japan
- 2007幎11æ
- OFDM or multicarrier systems have emerged as a key technology for current existing terrestrial wireless systems. Because of their advantages over a single carrier system, OFDM is undergoing rapid progress and inspiring numerous applications. However, many technical issues still exist for adopting OFDM to satellite communications, i.e., non-linear amplifier compensation. In this article, we present a detailed investigation of various non-linear compensation techniques and provide a better understanding of the research challenges.
Automotive Ultrasonic Array Emitter for Short-range Targets Detection
- H. Hatano, T. Yamazato, M. Katayama
- IEEE International Symposium on Wireless Communication Systems (ISWCS), pp.355-359, Trondheim, Norway
- 2007幎10æ
- https://doi.org/10.1109/ISWCS.2007.4392361
- We consider an application of a ultrasonic array emitter to automotive targets detection systems for short-range. Ultrasonic sensors are low cost and widely used. However detectable ranges do not meet the requirements for short-range applications, such as parking aid systems. In this paper, we propose a method which may achieve the emission to a desired area within limited time. We evaluate the expected accuracy of target position estimations by computer simulations. As a result, we show the ability of the ultrasonic sensors for parking aid systems.
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å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, USN2007-48, pp.73-76, åå€å±
- 2007幎10æ
- ç¡ç·ã»ã³ãµãããã¯ãŒã¯ã§ã¯, å€ãã®ã»ã³ãµããŒãã忣ããŠé
眮ãã, åããŒãã§èŠ³æž¬ãããããŒã¿ã¯ãã¥ãŒãžã§ã³ã»ã³ã¿ãŒã§åéããã. ã»ã³ãµããŒãã¯ãããŠãå°ããé»åãéãããŠãããã, è€éãªåŠçãåºæ¥ãéä¿¡ç¯å²ãçããã®ãšãªã£ãŠãã. ããã§, ããŒãéã®ååéä¿¡ã«ããäŒéè·é¢ã®å»¶é·ãå®çŸãã. ååéä¿¡ã«é¢ããç ç©¶ã¯ïŒè€éã§, å³ãããã£ãªã¢ã»äœçžåææ¡ä»¶ãå¿
èŠãšãããã®ãå€ãïŒæ¬çš¿ã§ã¯, å³ããåææ¡ä»¶ãªãã«, ã·ã³ãã«ãªæ¹åŒã§éæããååéä¿¡ãææ¡ãã. å
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ãå€åãããããšã§, åŸæ¥æ¹åŒã§çºçãããã±ãããã¹ãç¡ããããšãã§ãã. ãã®ææ¡æ¹åŒãFPGA ãçšããLED å¯èŠå
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A Novel Contention-Free Medium Access Control Protocol for Inter-Vehicle Communication Systems
- M. Masamura, H. Okada, S. Makido, T. Yamazato, M. Katayama
- First International Workshop on Mobile Vehicular Networks, Pisa, Italy
- 2007幎10æ
- https://doi.org/10.1109/MOBHOC.2007.4428733
- We propose a contention-free medium access control (MAC) protocol for inter-vehicle communication systems that share information for the improvement of safety drive on the highway. In the proposed system, contention-free medium access is achieved by periodical one-way token transmissions. The token contains the frame information about the transmission/reception phase. While the token is relaid by one-way, the vehicle which has the token can send a packet to both up- and down-link. The token transmission interval is set not to be interfered from other transmit vehicles at a receive vehicle. In addition, multiple channels are used and allocated dynamically for every token transmission to reduce the transmission waiting time. We also evaluate the maximum end-to-end transmission delay of the proposed protocol, and clarify that the proposed protocol can guarantee the transmission within allowable delay time.
A Route Selection Scheme for Multi-Route Coding in Multihop Cellular Networks
- H. Okada, H. Imai, T. Yamazato, M. Katayama, K. Mase
- IEEE Vehicular Technology Conference (VTC-Fall), Baltimore, USA
- 2007幎10æ
- https://doi.org/10.1109/VETECF.2007.18
- In the multihop cellular networks, multiple routes from a user station to a base station can be established because of the flexibility of network topology. In order to reduce packet errors of wireless transmissions, we proposed the multi-route coding scheme, in which packets are encoded and divided into subpackets, and they are transmitted on several routes from the user station to the base station. In order to improve the performance of the multi-route coding, a route selection scheme is very important issue. In this paper, we propose the route selection scheme for the multi-route coding in multihop cellular networks. The proposed scheme is based on the bit error rate of wireless links. We also apply the proposed route selection scheme to a hybrid routing protocol and evaluate its performance.
Analysis on Chaotic Sequence with Biased Values for Noncoherent Chaos Communication
- S. Arai, Y. Nishio, T. Yamazato
- International Symposium on Nonlinear Theory and its Applications (NOLTA), pp.144-147, Vancouver, Canada
- 2007幎9æ
- In this paper, we analyze a chaotic dynamics generating a chaotic sequence with biased values and apply it to noncoherent chaos communications. We examine a behavior of the chaotic dynamics by increasing the slope of the chaotic map and investigate the invariant measure and the correlation function. A high quality performance of noncoherent chaos communications is obtained by controlling the distribution of the chaotic sequence with biased values. Finally we carry out the computer simulation using its sequence and discuss the obtained results and the future problem for chaos communication.
Experiment on Hierarchical Transmission Scheme for Visible Light Communication using LED Traffic Light and High-Speed Camera
- S. Arai, S. Mase, T. Yamazato, T. Endo, T. Fujii, M. Tanimoto, K. Kidono, Y. Kimura, Y. Ninomiya
- IEEE International Symposium on Wireless Vehicular Communications (WiVeC), Baltimore, USA
- 2007幎9æ
- https://doi.org/10.1109/VETECF.2007.456
- LEDs are expected as lighting sources for next generation, and data transmission system using LEDs attract attention. In this paper, we present hierarchical coding scheme using LED traffic lights and high-speed camera for Intelligent Transport Systems (ITS) application. Further, if each of LEDs in traffic lights is individually modulated, parallel data transmissions are possible using a camera as a reception device. Such parallel LED-camera channel can be modeled as spatial low-pass filtered channel of which the cut-off frequency varies according to the distance. To overcome, we propose hierarchical coding scheme based on 2D fast Haar wavelet transform. As results, the proposed hierarchical transmission schemes outperform the conventional on-off keying and the reception of high priority data is guaranteed even LED-camera distance is further.
ãã«ãã»ã«OFDMAäžããªã³ã¯ã«ããããã£ãã«åå²ãçšããã©ã³ãã ã¢ã¯ã»ã¹ææ³ã«é¢ããäžæ€èš
- æšæå幞, 山鿬ä¹, çå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒ éä¿¡ãœãµã€ãšãã£å€§äŒ, B-5-62, p.384, é³¥å
- 2007幎9æ
- ã»ã«ã©ç¡ç·ã·ã¹ãã ã®äžããªã³ã¯ã«ãããã©ã³ãã ã¢ã¯ã»ã¹æ¹åŒãšããŠ, OFDMAã®åãµããã£ãã«ã«slotted-ALOHA ãé©çšããæ¹åŒãææ¡ãããŠãã. 以äž, ãã®æ¹åŒãOFDMA s-ALOHA ãšåŒã¶. ãã®ææ³ã¯, è² è·å€åã«é©å¿ã, ç¹ã«äœè² è·æã«é«ãã¹ã«ãŒããããå®çŸãã. ããããªãã, ãã«ãã»ã«ã«ãããä»ã»ã«ã®ãã±ããããã®å¹²æžã«ãã, ç¹ã«é«è² è·æã«ãããŠã¹ã«ãŒãããã倧ããäœäžããŠããŸããšããæ¬ ç¹ããã. æ¬ç ç©¶ã§ã¯, OFDMA s-ALOHA ã«ãããŠ, çç®ããã»ã«ã®åšèŸºã»ã«ã«ããããµããã£ãã«ã®å²åœã工倫ããããšã§, ããé«ãã¹ã«ãŒããããéæããã©ã³ãã ã¢ã¯ã»ã¹ææ³ãææ¡ãã.
Efficient Channel Estimation Scheme for Pulse-shaping OFDM Systems
- B.Mongol, T. Yamazato, M. Katayama
- International Symposium on Nonlinear Theory and its Applications (NOLTA), pp.92-95, Vancouver, Canada
- 2007幎9æ
- This paper proposes a low-complexity channel estimation sheme for the pulse-shaping OFDM systems in the highly mobile multipath environment. The estimation scheme is based on the tapped-delay-line model for the channel. The main idea behind our scheme is to approximate the fading process for each tap with finite terms of its Taylor series expansion. The proposed scheme also tracks the channel. We show that the channel can be estimated and tracked with reasonable mismatch error while using considerably short training period.
Distributed Space-Time Block Coding for Large and Undetermined Set of Relay Terminals
- R. Uchida, H. Okada, T. Yamazato, M. Katayama
- IEEE International Symposium on Personal, Indoor and Mobile Radio Communication (PIMRC), Athens, Greece
- 2007幎9æ
- In this manuscript, a spatial diversity scheme with multiple transmit and receive antennas together with multiple relay terminals for packet radio is considered. Correctly received signals at some relay terminals are re-transmitted to the receiver with the spatial diversity by STBC cooperative relaying scheme. To achieve high diversity order with the conventional STBC cooperative relaying scheme, relay terminals which re-transmit the signals are required to exchange signaling information with each another. However, the exchanging of the information causes delay of the signal transmission. Thus, in this manuscript, a novel signaling scheme for the STBC cooperative relaying is proposed. The proposed scheme releases relay terminals exchanging the signaling information. The proposed scheme also saves communication resources to provide flexibility for installation of relay terminals.
è»èŒçšã¬ãŒããããã¯ãŒã¯ã«ãããè€æ°é害ç©ã®äœçœ®æšå®ææ³ã«é¢ããäžæ€èš
- 矜å€éè£ä¹, 山鿬ä¹, 岡ç°å, çå±±æ£æ
- èªåè»æè¡äŒè«æé, vol.38, no.5, pp.191-196
- 2007幎9æ
- We research automotive radar networks with multiple radars set in the front of car. Especially, we consider data processing using measured ranges provided by the radars in order to estimate multiple target positions with high accuracy. This paper is composed of three steps. Firstly, we derive a method based on MAP estimation. Secondly, we propose a method which reduces the calculation complexity compared with the above MAP method. Finally, we introduce a method which can detect targets without ghost-targets in case the lacks of measured ranges are happened because of miss-detection. We evaluate the methods with computer simulations.
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å ±éä¿¡åŠäŒè«æèªïŒvol.J90A, no.9, pp.696-704
- 2007幎9æ
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- åç°ç¯€å, 山鿬ä¹, 岡ç°å, çå±±æ£æ
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å ±éä¿¡åŠäŒ éä¿¡ãœãµã€ãšãã£å€§äŒ, B-5-89, p.411, é³¥å
- 2007幎9æ
- è»è»ééä¿¡ãšè·¯è»ééä¿¡ã¯, é転æã«æ
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šæ§ã®åäžã茞éå¹çã®åäžããããããã®ãšããŠæ³šç®ãããŠãã. è€æ°ã®è»äž¡ã亀差ç¹ã«ãããŠéä¿¡ãè¡ãæ, é ã端æ«åé¡ãé »ç¹ã«çãã. ãã®åé¡ãçºçããŠããç¶æ³ã«ãããŠ, CSMA ã¯æ£ããåäœããªã. ããã«æ¯ã¹, CDMA slotted ALOHAã¯åæãã±ããéä¿¡ãå¯èœãªãã, é ã端æ«åé¡ã«å¯Ÿããèæ§ããã. æ¬çš¿ã§ã¯, è»è»ééä¿¡ã«ãããŠOFDMãçšããCSMAãšMulticarrier CDMA ãçšãã CDMA slotted ALOHAã®ã¹ã«ãŒãããç¹æ§ãæ¯èŒãã.
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- 2007幎8æ
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å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.RCS2007-68, pp.87-91, æ°æœ
- 2007幎8æ
- MC-CDMA ãçšããäžããªã³ã¯ã»ã«ã©ã·ã¹ãã ã§ã¯, 飿¥ã»ã«å
ã®åºå°å±ãã端æ«ãžãšéãããä¿¡å·ãå¹²æžãšãªã, ç¹ã«ã»ã«ç«¯ä»è¿ã«äœçœ®ãã端æ«ã®åä¿¡ç¹æ§ãå£åãã. æ¬çš¿ã§ã¯, MC-CDMA ãçšããã»ã«ã©ã·ã¹ãã äžããªã³ã¯ã«ãããŠ, åºå°å±ãåã»ã«å
ã®ç«¯æ«ãžãšä¿¡å·ãéä¿¡ããéã«éæ¬ çã«ä¿¡å·ãéä¿¡ããããšã§, 飿¥ã»ã«å¹²æžã倧ããªç°å¢äžã§åä¿¡ç¹æ§ãæ¹åããææ³ã«ã€ããŠè¿°ã¹ã. ææ¡æ¹åŒã§ã¯ååºå°å±ã飿¥ã»ã«å¹²æžã倧ããªç«¯æ«ãžãšä¿¡å·ãéä¿¡ããéã«ä¿¡å·ã鿬 çã«éä¿¡ãã. ãã®ãã, 端æ«ãä¿¡å·ãåä¿¡ããéã«é£æ¥ã»ã«ä¿¡å·ã¯éæ¬ çã«åä¿¡ãã, ã»ã«éå¹²æžã¯éšåçãªå¹²æžãšãªã. ãã®éšåçãªå¹²æžã«åãããŠçååšã®éã¿ã倿Žããããšã§ã»ã«éå¹²æžã®åœ±é¿ãæããããšãã§ãã. çµæãšããŠ, ææ¡ææ³ã§ã¯åŸæ¥ææ³ããã誀ãçç¹æ§ãæ¹åã, å¹²æžé»åã倧ããªå Žåã®ã¹ã«ãŒãããç¹æ§ãé«ããããšãã§ãã.
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å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.WBS2007-30, SIP2007-81, pp.53-58, é«ç¥
- 2007幎8æ
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- åç°ç¯€å, 山鿬ä¹, 岡ç°å, çå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.RCS2007-55, pp.13-18, æ°æœ
- 2007幎8æ
- æ¬çš¿ã§ã¯, è»è»ééä¿¡ã«ãã㊠OFDM ãçšãã CSMA ãšMC-CDMA ãçšãã CDMA slotted ALOHA ã®ã¹ã«ãŒãããç¹æ§ãæ€èšãã. ç¹ã«, é ã端æ«åé¡ãç¡èŠã§ããªããããªç¶æ³ã«ãããŠäž¡è
ãæ¯èŒãã. é ã端æ«åé¡ã¯, 亀差ç¹ãªã©ã§è€æ°ã®è»äž¡ãéä¿¡ãè¡ããããªæã«çãã. ãã®ãã, CSMAã®ã¹ã«ãŒãããç¹æ§ã¯å£åãã. äžæ¹, CDMA slotted ALOHAã¯, åæãã±ããéä¿¡ãå¯èœãªãã, é ã端æ«åé¡ã«å¯Ÿããèæ§ããã. ããã, MC-CDMAå€èª¿ãè¡ã£ãŠããããããŒã¿ã¬ãŒããäœã. ãã£ãŠ, é ã端æ«åé¡çºçæã«ãããŠã, CDMA slotted ALOHAã®ã¹ã«ãŒãããã¯CSMAã»ã©é«ããªã. çµæãã, OFDM ãçšãã CSMA ã®æ¹ã MC-CDMA ãçšããCDMA slotted ALOHAã®ã¹ã«ãŒãããããé«ãããšãåãã£ã. ããã, æãè¿ãè»äž¡ãã ã®ä¿¡å·ããåä¿¡ã§ããªã. ããã«æ¯ã¹, CDMA slotted ALOHA ã¯åæã«è€æ°ã®è»äž¡ããä¿¡å·ãåä¿¡ã§ãã. ãã®ç¹é·ã¯, å®å
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- 2007幎7æ
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鳿³¢ã»ã³ãµã§ã¯, æå€§æ€åºè·é¢ãçããã, é«åºŠãªé§è»è£å©ãè¡ãããã«ã¯, æå€§æ€åºå¯èœè·é¢ã䌞ã°ãå¿
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鳿³¢ãšããã¿ãçšããŠã¢ã¬ã€ãæ§æããããšãèãã. ãããŠ, ã¢ã¬ã€ãçæããæåæ§ãã¿ãŒã³ã«é©ããããŒã æäœææ³ãææ¡ãã. ããã«ãã, å°ãªãã¹ãã£ã³åæ°ã§, é«åºŠãªé§è»è£å©ã§æ±ããããæ€åºé åã«å¯ŸããŠä¿¡å·ã®æŸå°ãå¯èœãšãªãããšã確èªãã.
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å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, Vol.OCS2007-15, pp.31-35, åæµ·é
- 2007幎6æ
- LED ã®èŒåºŠã人ã®ç®ã«ã¯æç¥ã§ããªãçšã®é床ã§å€ããäºã§ç¡ç·éä¿¡ãè¡ãå¯èŠå
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ç¯ã®ã¹ãã¯ãã«ã枬å®ã, 匷床ãåšæ³¢æ°ã«ãã£ãŠå€§ããç°ãªãããšã瀺ã, ããã«SNR ãæ±ãã.
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- 柀ç°åŠ, 山鿬ä¹, çå±±æ£æ
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å ±éä¿¡åŠäŒè«æèª, vol.J90-B, no.6, pp.577-584
- 2007幎6æ
- çŽäº€åšæ³¢æ°åå²å€éïŒOFDMïŒä¿¡å·ãçšããŠãã±ããéä¿¡ãè¡ãéã«ïŒé ã端æ«åé¡çãåå ãšãããã±ããè¡çªãçºçããå Žåã«çããå信誀ãçç¹æ§ã®å£åãïŒã¢ããã°ïŒãã£ãžã¿ã«å€æåšïŒADCïŒä»¥éã®ãã£ãžã¿ã«ä¿¡å·åŠçã§è»œæžããåä¿¡æ©ãææ¡ããïŒææ¡åä¿¡æ©ã¯ïŒADCåºåãµã³ãã«ã®æ¯å¹
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¥åãšãªãè»å€å®å€ãå¶åŸ¡ããããšã«ããïŒç¹æ§å£åãè£åããïŒèšç®æ©ã·ãã¥ã¬ãŒã·ã§ã³ã«ããïŒ16QAM/OFDMä¿¡å·ãçšããåž æãã±ãããšãšãã«ïŒä»ãŠãŒã¶ããã®å¹²æžãã±ãããåæã«åä¿¡ãããå Žåã®åä¿¡ãã±ãã誀ãçïŒPERïŒç¹æ§ãè©äŸ¡ããçµæïŒææ¡åä¿¡æ©ã«ããå¹²æžåœ±é¿ã®è»œæžå¹æãèŠãããããšã瀺ããïŒããã«ããé ã端æ«åé¡çã«ããå¹²æžçºçæã«ïŒåŸæ¥å信誀ããåå ã§ç Žæ£ãããŠãããã±ããã®äžéšãïŒç°¡æãªæ§æã§å®çŸå¯èœãªææ¡åä¿¡æ©ã«ããæ£åžžã«åä¿¡å¯èœã§ããããšã瀺ããïŒ
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- 倧蟻倪äž,山鿬ä¹, çå±±æ£æ
- é»åæ
å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, Vol.OCS2007-14, pp.25-29, åæ³
- 2007幎6æ
- LEDã®èŒåºŠã人éã®ç®ã«ã¡ãã€ããæããªãçšåºŠã®é床ã§å€èª¿ããããšã§éä¿¡ãå®çŸããå¯èŠå
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Cooperative Transmission Scheme in Distributed Sensor Network for Extension of Transmission Range
- K. Nakao, T. Yamazato, H. Okada, M. Katayama
- Fourth International Conference on Networked Sensing Systems, pp.89-92, Braunschweig, Germany
- 2007幎6æ
- https://doi.org/10.1109/INSS.2007.4297396
- We consider a distributed transmission of data packet to a sink where the distance for a sensor node to the sink is much longer than a sensor node can transmit. We give a simple modification in the transmitter, i.e., multiplication of random phase before the transmission. Thanks to a strong error correcting code, it is possible to extend the transmission range as the received amplitude varies symbol by symbol for our scheme while whole data packet may be lost for the conventional scheme.
Throughput Comparison of CSMA and CDMA slotted ALOHA in Inter-Vehicle Communication
- A. Sakata, H. Okada, T. Yamazato, M. Katayama
- 7th International Conference on ITS Telecommunications, pp.52-57, Sophia antipolis, France
- 2007幎6æ
- https://doi.org/10.1109/ITST.2007.4295832
- This paper compare the throughput performance of a carrier-sense multiple access (CSMA) scheme that uses an orthogonal frequency division multiple access (OFDM) physical layer and a CDMA slotted ALOHA scheme based on multicarrier CDMA (MC-CDMA) in inter-vehicle communication (IVC). In particular, we compare the throughputs in a situation where a hidden terminal is no longer negligible. We encounter such a situation in an intersection where two or more cars are crossing by. In a hidden terminal situation, the CSMA scheme may degrade throughput. On the other hand, CDMA slotted ALOHA has a resistance to the hidden terminal situation as it can support simultaneous packets. However, the transmission data rate is much slow because of the spreading. Thus the total throughput may not be as high as the CSMA based OFDM even in a hidden terminal situation. As a result, we show that the CSMA based OFDM system shows better total throughput than CDMA slotted ALOHA in all region. But, only the signal from the nearest car can be received. On the contrary, CDMA slotted ALOHA can be received many packets simultaneously. This is much preferable feature for safety driving.
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- å°æå¥å€ªéïŒå±±éæ¬ä¹ïŒå²¡ç°åïŒçå±±æ£æ
- Wireless Technology Park 2007 ã¢ã«ããã¢ããã°ã©ã , pp.26-27, 暪æµ
- 2007幎4æ
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- 2007幎4æ
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A Simple Estimator of Multiple Target Positions for Automotive Short Range Radar Networks
- H. Hatano, T. Yamazato, H. Okada, M. Katayama
- IEEE Vehicular Technology Conference (VTC-Spring), pp.2511-2515, Dubliln, Ireland
- 2007幎4æ
- https://doi.org/10.1109/VETECS.2007.517
- For safety applications, automotive radar networks show an interesting potential. Apart from long range radars, networked short range radar systems are under development. Additional applications can be accomplished, such includes precrash detection, parking aid and blind spot surveillance. We research the automotive radar networks using short range radars. The network is built with multiple radars. In this paper, we consider data processing using measured ranges provided by the radars in order to estimate multiple target positions with high accuracy. Firstly, we derive a method based on MAP stimation. Secondly, we propose a method which reduces the calculation complexity compared to the above MAP method. Finally, we introduce a method which can detect targets with low ndetected targets. The case often happens when the measured ranges are lost because of miss-detections.We evaluate the performance th computer simulations.
Route Diversity Effect of Joint Decoding Using Correlation between Observed Data Sequences in Sensor Networks
- H. Okada, K. Kobayashi, T. Yamazato, K. Mase
- IEEE Vehicular Technology Conference (VTC-Spring), pp.217-221, Dublin, Ireland
- 2007幎4æ
- https://doi.org/10.1109/VETECS.2007.57
- In sensor networks, because of densely deployment of sensor nodes, sensing area of each sensor node is overlapped with each other and its observed data sequence is correlated. The joint decoding scheme that uses the correlation between the observed data sequences can reduce bit errors in the wireless channel. In this paper, we extend the joint decoding to the case of more than two-hop transmission. For such extension, selection of fusion scheme is very important issue. If the global fusion scheme is employed and the observed data sequence of each sensor node is transmitted on an independent route, route diversity effect could be obtained by using the correlation between observed data sequences. We compare the bit error rate performance of local and global fusion schemes and clarify the route diversity effect.
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- Wireless Technology Park 2007 ã¢ã«ããã¢ããã°ã©ã , pp.50-51, 暪æµ
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- IEICE Transactions on Communications, vol.E89-B, no.12, pp.3250-3256
- 2006幎12æ
- This paper discusses the influence of the nonlinearity of analog-to-digital converters (ADCs) on the performance of orthogonal frequency division multiplexing (OFDM) receivers. We evaluate signal constellations and bit error rate performances while considering quantization errors and clippings. The optimum range for an ADC input amplitude is found as a result of the trade-off between quantization error and the effects of clipping. In addition, it is shown that the peak-to-average power ratio (PAPR) of the signal is not a good measure of the bit error rate (BER) performance, since the largest peaks occur only with very low probabilities. The relationship between the location of a subcarrier and its performance is studied. As a result, it is shown that the influence of the quantization error is identical for all subcarriers, while the effects of clipping depend on the subcarrier frequency. When clipping occurs, the BER performance of a subcarrier near the center frequency is worse than that near the edges.
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å ±éä¿¡åŠäŒè«æèª, vol.J89-A, no.12, pp.1044-1056
- 2006幎12æ
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å ±çè«ãšãã®å¿çšã·ã³ããžãŠã ïŒvol.2, pp. 691–694,, åœé€š
- 2006幎11æ
- æ¬çš¿ã§ã¯ïŒOFDMä¿¡å·ãçšããŠãã±ããéä¿¡ãè¡ãéã«ïŒé ã端æ«åé¡çãåå ãšããèªãã£ãã«ã®å¹²æžãçºçããå Žåã«çããåä¿¡å質ã®å£åãADC以éã®ãã£ãžã¿ã«ä¿¡å·åŠçã§è»œæžããåä¿¡æ©ãææ¡ããïŒææ¡åä¿¡æ©ã§ã¯ïŒADCåºåãµã³ãã«ã®æ¯å¹
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Influence of Transmit and Receive Correlations on Performance of the MIMO System with Multiple Antennas and Relay Terminals
- R. Uchida, H. Okada, T. Yamazato, M. Katayama
- MObile Radio Interdisciplinary Workshop (MORI Workshop), Daejeon, Korea
- 2006幎11æ
MIMO Zero-forcing Equalizer for BFDM/OQAM Systems in the Highly Mobile Environments
- B. Mongol, T. Yamazato, H. Okada, M. Katayama
- IEEE Global Communications Conference (GLOBECOM), WLC01-6, San Francisco, CA, USA
- 2006幎11æ
- https://doi.org/10.1109/GLOCOM.2006.620
- Pulse-shaping OFDM is well-known that it performs well in a mobile environment comparing with conventional OFDM. However, in highly mobile environment intersymbol and intercarrier interferences (ISI/ICIs) increase and can no longer be neglected. These ISI/ICIs deteriorate the performance of the systems. Proper channel equalization is needed for further improvement of the systems. In this paper, more general case, namely Biorthogonal Frequency Division System based on Offset QAM (BFDM/OQAM) is considered. We propose a multi-input multi-output (MIMO) transversal filter to equalize the time-frequency dispersive channel. Tap weights are calculated using the zero-forcing (ZF) algorithm. We also propose maximum-likelihood channel estimator and its low-complexity version. The proposed system can significantly improve the performance of BFDM/OQAM systems in the highly mobile environment.
MIMO Zero-forcing Equalizer for BFDM/OQAM Systems in Time-Frequency Dispersive Channels
- B. Mongol, T. Yamazato, H. Okada, M. Katayama
- IEICE Transactions on Fundamentals, vol.E89-A, no.11, pp.3114-3122
- 2006幎11æ
- Pulse-shaping OFDM is well-known that it performs well in a mobile environment compared with conventional OFDM. However, in a highly mobile environment intersymbol and intercarrier interferences (ISI/ICIs) increase and can no longer be neglected. These ISI/ICIs deteriorate the performance of the systems. Proper channel equalization is needed for further improvement of the systems. In this paper, a more general case, namely Biorthogonal Frequency Division System based on Offset QAM (BFDM/OQAM) is considered. We propose a multi-input multi-output (MIMO) transversal filter to equalize the time-frequency dispersive channel. Tap weights are calculated using the zero-forcing (ZF) algorithm. We also propose maximum-likelihood channel estimator and its low-complexity version. The proposed system can significantly improve the performance of BFDM/OQAM systems in the highly mobile environment.
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Influence of Transmit and Receive Correlations on Performance of the MIMO System with Multiple Antennas and Relay Terminals
- R. Uchida, H. Okada, T. Yamazato, M. Katayama
- International Symposium on Information Theory and Its Applications (ISITA), pp.454-459, Seoul, Korea
- 2006幎10æ
- In this manuscript, spatial diversity for in-factory environments is considered. The proposed scheme uses multiple antennas at a transmitter and a receiver, and also multiple relay terminals to provide diversity gain against fading and shadowing. If the separation of antennas at the transmitter or the receiver is not enough, then diversity gain is influenced by correlation at the transmitter or the receiver. This manuscript shows the analytical and numerical results of the effects of transmit and receive correlations on bit error performance of the proposed spatial diversity scheme.
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- 平山泰åŒ, 岡ç°å, 山鿬ä¹, çå±±æ£æ
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å ±éä¿¡åŠäŒè«æèªïŒvol.J89-B, no.10, pp.2047-2051
- 2006幎10æ
- è€æ°çµè·¯ãã±ããåææ³ã¯ãããã¯ãŒã¯äžã«èšå®ãããè€æ°çµè·¯ãå©çšãã誀ãå¶åŸ¡ïŒãã€ããŒã·ãåææ³ã§ããïŒæ¬ã¬ã¿ãŒã§ã¯ïŒçµè·¯éžæåºæºãšããŠçµè·¯ã®ããã誀ãçïŒãã±ããå°é確ç䞊ã³ã«ãããæ°ãçšããå Žåã®è€æ°çµè·¯ãã±ããåææ³ã® æ§èœãæ¯èŒããïŒ
Iterative Joint Channel-Decoding Scheme Using the Correlation of Transmitted Information Sequences in Sensor Networks
- K. Kobayashi, T. Yamazato, H. Okada, M. Katayama
- International Symposium on Information Theory and Its Applications (ISITA), pp.808-813, Seoul, Korea
- 2006幎10æ
- In this study, we consider joint channel decoding of Turbo code for multiple correlated data that are observed by sensor nodes densely deployed in a sensor field. We focus on the correlation properties of observation data and try to reduce decoding error by an iterative procedure. An approach to use practical channel codes for more than two correlated data is still not presented. A problem in the extension to cases of more than two sensor nodes is how to use the information of correlation obtained from observation data. In this study, we propose an iterative channel decoding scheme that uses them with weighting. We show that when the number of sensor nodes is increased, decoding performance improvement cannot be achieved by simple weighting, and so a more appropriate weight is needed. We find the optimum weight that minimizes the bit error rate from the analytical formula for uncoded BPSK and apply it to the case of Turbo code.
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- æç°è¯ä», 岡ç°å, 山鿬ä¹, çå±±æ£æ
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å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol. RCS2006-142, pp. 55-60, éŠå·ç髿Ÿåž
- 2006幎10æ
- ãã±ããç¡ç·äŒéã·ã¹ãã ã«ãããŠïŒéåä¿¡æ©éã«è€æ°ã®åçäžç¶åšã眮ã空éãã€ãã·ããèããïŒéä¿¡æ©ããã®ä¿¡å·ã誀ããªãåä¿¡ããäžç¶åšçŸ€ã¯ïŒåä¿¡æ©ã«å¯ŸããŠSTBCãçšããååäžç¶ãè¡ããã®ãšããïŒããã«ããéä¿¡äžç¶åšå°æ°ã«å¿ãããã€ãã·ãå©åŸãæåŸ
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- 2006幎10æ
- ITSãã»ã³ãµãããã¯ãŒã¯ã®ããã«ãã芳枬ããŒã¿ãç¡ç·ãããã¯ãŒã¯ãéã㊠äŒéããå ŽåïŒéä¿¡æ
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- 岡ç°åïŒå°æå¥å€ªéïŒå±±éæ¬ä¹ïŒéç¬æ²äž
- é»åæ
å ±éä¿¡åŠäŒ åºç€ã»å¢çãœãµã€ãšãã£å€§äŒ, A-21-15, p.227, éæ²¢
- 2006幎9æ
- ã»ã³ãµãããã¯ãŒã¯ã§ã¯é垞芳枬ããŒã¿ã«çžé¢ããã, ãã®çžé¢ãå©çšããããšã§ç¹æ§åäžãå³ã誀ãèšæ£åŸ©å·æ¹åŒãææ¡ãããŠãã. æ¬ç ç©¶ã§ã¯çžé¢ãå©çšãã誀ãèšæ£åŸ©å·æ³ã«ãããŠ, ã°ããŒãã«ãã¥ãŒãžã§ã³æ¹åŒãšããŒã«ã«ãã¥ãŒãžã§ã³æ¹åŒãšãã£ããã¥ãŒãžã§ã³æ¹åŒã®éãã«ãã埩å·ç¹æ§ãžã®åœ±é¿ãæ€èšãã.
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å ±éä¿¡åŠäŒ éä¿¡ãœãµã€ãšãã£å€§äŒ, B-17-5, p.515, éæ²¢
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The Effect of Multipath Hybrid Routing Protocol in Multihop Cellular Networks
- H. Imai, H. Okada, T. Yamazato, M. Katayama
- IEEE International Symposium on Personal Indoor and Mobile Radio Communication (PIMRC), Helsinki, Finland
- 2006幎9æ
- This paper examines multihop cellular networks. There are some issues in these networks, such as route loss due to topological change and packet errors due to wireless nodes relay. To overcome these issues, we use a multiple route coding scheme in which packets are transmitted on multiple routes from a user node to multiple base stations. This scheme can achieve a diversity gain by combining packets that are transmitted along multiple routes. Some challenges must be met to establish multiple routes for this scheme. In this paper, we propose a routing protocol for multiple route coding. The key idea of this proposed scheme is using a hybrid routing protocol. This can mitigate an increase in control packets and multiple disjoint routes can be constructed. We evaluate the performance of this proposed scheme.
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- æç°è¯ä», 岡ç°å, 山鿬ä¹, çå±±æ£æ
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å ±éä¿¡åŠäŒ éä¿¡ãœãµã€ãšãã£å€§äŒ, B-5-122, p.482, éæ²¢
- 2006幎9æ
- ãã§ãŒãžã³ã°ã»ã·ã£ããŠã€ã³ã°ç°å¢äžã§ã®ç¡ç·éä¿¡ã·ã¹ãã ã®é«ä¿¡é Œåææ³ãšããŠæ¢ã«çè
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- èªåè»æè¡äŒãç§å£å€§äŒ, No. 134-06, pp.21-26, Sept. 2006., æå¹
- 2006幎9æ
- We research automotive radar networks with multiple radars set in the front of car. Especially, we consider data processing using measured ranges provided by the radars in order to estimate multiple target positions with high accuracy. This paper is composed of three steps. Firstly, we derive a method based on MAP estimation. Secondly, we propose a method which reduces the calculation complexity compared with the above MAP method. Finally, we introduce a method which can detect targets without ghost-targets in case the lacks of measured ranges are happened because of miss-detection. We evaluate the methods with computer simulations.
Channel Estimation for BFDM/OQAM System in Dispersive Time-Varying Channels
- B. Mongol, T. Yamazato, H. Okada, and M. Katayama
- International Symposium on Wireless Communication Systems (ISWCS), pp.159-163, Valencia, Spain
- 2006幎9æ
- https://doi.org/10.1109/ISWCS.2006.4362279
- Pulse-shaping OFDM is well-known that it performs well in a mobile environment comparing with conventional OFDM. However, in highly mobile environment intersymbol and intercarrier interferences (ISI/ICIs) increase and can no longer be neglected. These ISI/ICIs deteriorate the performance of the systems. Practically, proper channel equalization and estimation are needed for further improvement of the systems. In this paper, more general case, namely Biorthogonal Frequency Division System based on Offset QAM (BFDM/OQAM) is considered. We first derive analytical equations for the channel statistics. Further, we propose maximum-likelihood channel estimator and its low-complexity versions. The performance analysis shows that the estimators are robust against Doppler spread of the channels.
A Mathematical Model of Noise in Narrowband Power-Line Communication Systems
- M. Katayama, T. Yamazato, H. Okada
- IEEE Journal on Selected Areas in Communications, vol.24, no.7, pp.1267-1275
- 2006幎7æ
- This manuscript introduces a mathematically tractable and accurate model of narrowband power-line noise based on experimental measurements. In this paper, the noise is expressed as a Gaussian process whose instantaneous variance is a periodic time function. With this assumption and representation, the cyclostationary features of power-line noise can be described in close form. The periodic function that represents the variance is then approximated with a small number of parameters. The noise waveform generated with this model shows good agreement with that of actually measured noise. Noise waveforms generated by different models are also compared to that of the proposed mode.
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å ±éä¿¡åŠäŒæè¡å ±å, vol.SIP2006-58, pp. 25-30, é·å²¡ç§åŠæè¡å€§åŠ
- 2006幎7æ
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Throughput Evaluation of ARQ Scheme for Multi-route Coding in Wireless Multi-hop Networks
- H. Okada, T. Wada, K. Ohuchi, M. Saito, T. Yamazato, M. Katayama
- IEEE Vehicular Technology Conference (VTC-Spring), pp.668-672 , Melbourne, Australia
- 2006幎5æ
- https://doi.org/10.1109/VETECS.2006.1682908
- For reduction in bit errors on wireless channels, we proposed the multi-route coding scheme on multiple routes for wireless multi-hop networks. In this paper, we introduce ARQ to the multi-route coding. In the multi-route coding, the destination node combines and decodes sub packets which are encoded and divided by the source node. The intermediate node relays a sub packet, that is, only a part of a packet. Therefore, the intermediate node cannot detect packet errors, and only the destination node can do after combining and decoding sub packets. We propose the ARQ scheme between the source node and the destination node. We analyze the proposed ARQ scheme and evaluate the throughput performance.
Multi-route Coding in Wireless Multi-hop Networks
- H. Okada, N. Nakagawa, T. Wada, T. Yamazato, M. Katayama
- IEICE Transactions on Communications, vol.E89-B, no.5, pp.1620-1626
- 2006幎5æ
- Wireless multi-hop networks have drawn much attention for the future generation mobile communication systems. These networks can establish multiple routes from a source node to a destination node because of flexible construction of network topology. The transmission by multiple routes has enough capability to achieve reliable communication because we can expect to obtain diversity gain by multiple routes. In this paper, we propose the multi-route coding scheme. At first, we discuss a channel model in multi-hop networks employing regenerative relay, which we named the virtual channel model. By using the virtual channel model, a packet is encoded on multiple routes as follows; a bit sequence of a packet is encoded and divided into subpackets, and each subpacket is transmitted on each route. We evaluate its packet error rate performance, and clarify effectiveness of the proposed scheme. In general, we should face degradation of a route condition such as the case when a subpacket does not reach a destination node. Hence, we have to consider the influence of subpacket loss. We also investigate it, and show tolerance of the proposed scheme over that.
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- 2006幎3æ
- ã»ã³ãµãããã¯ãŒã¯ã§ã¯ïŒäžã€ã®èŠ³æž¬å¯Ÿè±¡ã«å¯ŸããŠè€æ°ã®ã»ã³ãµããŒãããã®æ
å ±ããã¥ãŒãžã§ã³ã»ã³ã¿ãŒã§çµ±ååŠçããããšã§ïŒç²ŸåºŠã®é«ã芳枬ãå®çŸã§ããïŒãã®ãããªå ŽåïŒåã
ã®ã»ã³ãµããŒãã§åŸããã芳枬ããŒã¿ã¯äºãã«çžé¢ãæã€ããšã«ãªãïŒæ¬çš¿ã§ã¯ïŒãã®èŠ³æž¬ããŒã¿éã®çžé¢ãå©çšããŠïŒãã¥ãŒãžã§ã³ã»ã³ã¿ãŒã«ãããŠé信路誀ãã®æå¶ãå®çŸããããšãç®çãšãïŒç¹ã«ïŒéä¿¡æ
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- æ¬çš¿ã§ã¯ïŒOFDMåä¿¡æ©ã«ãããADC ã®å
¥åãæé©ã«å¶åŸ¡ãããªãã£ãå Žåã«çããç¹æ§å£åã軜æžããåä¿¡æ©ãææ¡ããïŒããã«ãã®ææ¡ååä¿¡æ©ãçšããŠ16QAM/OFDMä¿¡å·ãåä¿¡ããéã®ããã誀ãç(BER)ç¹æ§ãè©äŸ¡ãïŒææ¡ååä¿¡æ©ã®æå¹æ§ã瀺ããïŒ
Correlations of noise waveforms at different outlets in a power-line network
- A. Kawaguchi, H. Okada, T. Yamazato, M. Katayama
- IEEE International Symposium on Power Line Communications and Its Applications (ISPLC), pp.92-97, Orlando, Florida, USA
- 2006幎3æ
- This manuscript discusses the relationships of noise waveforms measured at different outlets in a three-wire single-phase (one neutral and two live conductors) power-line network. As a result of experimental measurements, it is confirmed that instantaneous noise voltages at two different outlets have high correlations if the outlets are connected to the same live conductor in a distribution board, while the outlets for the different live conductors provide noise waveforms with low correlations. It is also shown that the instantaneous noise powers and cyclic averaged noise powers as time functions have large correlations even at a pair of outlets connected to the different live conductors. The correlation coefficients for instantaneous voltages and powers are also calculated as the frequency functions.
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å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.RCS2005-207, pp.175-180, YRP
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Robust BFDM/OQAM Receiver for Time-Frequency Dispersive Channels
- B. Mongol, T. Yamazato, H. Okada, and M. Katayama
- Technical Report of IEICE, vol.WBS2005-112, pp.19-24, Nagoya, Japan
- 2006幎3æ
- Biorthogonal Frequency Division Multiplexing based on Offset QAM (BFDM/OQAM) system is one of the pulse-shaping versions of Orthogonal Frequency Division Multiplexing (OFDM) systems. It allows optimal Gaussian transmitting pulse at critical sampling i.e., maximum spectral efficiency. In this paper we propose a robust receiver for BFDM/OQAM systems in highly mobile environment. The idea behind our approach is to employ Multi-Input Multi-Output zero-forcing (MIMO-ZF) transversal filter to equalize the channel. The equalizer requires knowledge of the channel status. The channel is estimated by using Maximum-Likelihood method. We evaluate the error rate performance of the proposed system in the time-frequency dispersive channels.
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- 第ïŒåã¢ãããã¯ãããã¯ãŒã¯ã»ã¯ãŒã¯ã·ã§ãã, pp.7-5 - 7-8, åºå³¶
- 2006幎1æ
- ã»ã«ã©ã·ã¹ãã ã«ç¡ç·ãã«ããããéä¿¡ãå©çšãããã«ããããã»ã«ã©ãããã¯ãŒã¯ã§ã¯ïŒãããã¯ãŒã¯ããããžã®å€åã«ããçµè·¯ã®æ¶å€±ãè€æ°äžç¶ã«ãããã±ãã誀ããªã©ã®åé¡ãããïŒããã§ïŒè€æ°ã®çµè·¯ã§è€æ°ã®åºå°å±ã«ãã±ããã®éä¿¡ãè¡ãããšã§èª€ãã軜æžããããšãã§ããè€æ°çµè·¯ç¬Šå·åãé©çšããããšãèããïŒæ¬ç ç©¶ã§ã¯ïŒè€æ°çµè·¯ç¬Šå·åã®ããã®çµè·¯æ§ç¯æ³ãææ¡ããïŒæ¬ææ³ã§ã¯ïŒproactiveåãšreactiveåãçµã¿åãããhybridåã®ã«ãŒãã³ã°ãããã³ã«ã§ããïŒå¶åŸ¡ãã±ããã®éãæå¶ãã€ã€ïŒè€æ°ã®ç¬ç«ãªçµè·¯ãæ§ç¯å¯èœã§ããææ¡ææ³ãåŸæ¥ã®ãããã³ã«ãšæ¯èŒããŠç¹æ§ãè©äŸ¡ããïŒ
Ultra-Wideband Chaotic Radar and Clutter Reduction Methods
- N. Dake, Y. Uwate, Y. Nishio, T. Yamazato
- Journal of Signal Processing, vol.9, no.6, pp.473-478
- 2005幎12æ
- Chaos could generate nonperiodic sequences with infinite lengths theoretically. In this paper, we propose a UWB (ultra-wideband) chaotic radar, whose transmitted signal is generated by a chaotic map. Since it is important to remove various noises called clutter in a radar, we focus mainly on the removal of clutter by applying three clutter reduction methods. We derive the probability density function of power, the distances between the transmitted signals and the recovered signals, and the detection probability, using computer simulations, and the performance of the proposed radar is evaluated.
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- 2005幎12æ
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- 2005幎12æ
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Characterization of a simplified regenerative repeater for broadband satellite communications
- H. Kuwamura, A. Ogawa, T. Yamazato
- Technical Report of IEICE, vol.SAT2005-22, pp.33-35
- 2005幎10æ
Successive Interference Cancellation for Hierarchical Parallel Optical Wireless Communication Systems
- H. Okada, K. Masuda, T. Yamazato, M. Katayama
- Asia-Pacific Conference on Communications (APCC), pp.788-792, Perth, Australia
- 2005幎10æ
- A parallel optical wireless communication system using two-dimensional LED array (2D LED array) and two-dimensional image sensor (2D image sensor) was proposed for the visible light communication systems. In this system, each LED of the 2D LED array is individually modulated, and the 2D image sensor recognizes each LED modulated data. However, the received data pattern will be degraded due to reduction of pixel size and/or defocussing of the LED data pattern. This phenomenon corresponds to the degradation of high spatial frequency components of the received data pattern. To overcome, we employ a hierarchical transmission scheme at a transmitter and a successive interference cancellation at a receiver. By allocating high priority data to low frequency components and low priority data to high frequency components, the reception of high priority data can be guaranteed. We also attempt to apply interference cancellation to overcome the degradation of high spatial frequency components of the received data pattern. By evaluating the bit error rate, we clarify the effect of the proposed system.
Outage Probability of a Macro and Micro MIMO Diversity Scheme in an Indoor Fading and Shadowing Environment
- R. Uchida, H. Okada, T. Yamazato, M. Katayama
- IEICE Transactions on Fundamentals, vol.E88-A, no.10, pp.2945-2951
- 2005幎10æ
- In this manuscript, a layered macro / micro diversity scheme is introduced at the receiver side of a MIMO STBC wireless control system under fading and shadowing environment. The combination of the outputs of micro diversity is based on soft-decision values, while the macro diversity branches are combined based on hard decision values. As a measure of the reliability of the system, the outage probability of frame-error rate is employed. The performance of the proposed system is analytically and numerically evaluated and the impact of the macro diversity in the outage probability is clarified.
A Note on the Simple Regenerative Repeating Process for Communication Satellite
- T. Yamazato, A. Ogawa
- Technical Report of IEICE, vol.SAT2005-21, pp.27-32, Nagoya, Japan
- 2005幎10æ
- We have been working on a relay process of communication satellite. We omit the regenerative process at the satellite. Only routing and other necessary operation are performed at satellite. Simple configuration and signal processing may promise robust and long-lasting operations in space. We call it simple regenerating repeater. However, an issue is how to realize the reliable transmission even if we omit the error correcting and detecting process at the satellite. To overcome this issue, we propose to place the error detection code prior to QAM mapping. Using the status of error detector, it is possible to give accuracy to the received signal so we can improve the performance by soft decoding. The FPGA experimental boards of the system are also introduced
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å ±éä¿¡åŠäŒ éä¿¡ãœãµã€ãšãã£å€§äŒ, B-5-156, p.556, æå¹
- 2005幎9æ
- æ¬çš¿ã§ã¯ïŒç£æ¥æ©åšã®å¶åŸ¡ä¿¡å·ããã£ãžã¿ã«ç¡ç·äŒéããå Žåã«ïŒå¶åŸ¡æ
å ±ã®äŒé誀ããšäŒéé »åºŠãå¶åŸ¡åºåã«äžãã圱é¿ã«ã€ããŠèããïŒ1次ã®ãã£ãŒãããã¯å¶åŸ¡ç³»ã«å¯ŸããŠç¡ç·éä¿¡è·¯ãä»ããŠå¶åŸ¡ä¿¡å·ãäžãïŒæ§ã
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On the Second-order Statistics of the Channel Parameters for BFDM/OQAM Systems
- B. Mongol, T. Yamazato, H. Okada, M. Katayama
- International Symposium on Wireless Communication Systems (ISWCS), WS4-6, Siena, Italy
- 2005幎9æ
- Recently, there has been increased interest in using multicarrier systems in rapidly time-varying multipath environment.ãBiorthogonal Frequency Division Multiplexing based onãOffset QAM (BFDM/OQAM) is an attractive modulation methodãsince it allows time-frequency well-localized pulses even at criticalãsampling (i.e. maximum spectral ef ciency). BFDM/OQAMãsystem is naturally strong against intersymbol and intercarrierãinterference (ISI/ICI). However, for further improvement of theãsystem a study on the channel statistics is needed. In this paper weãanalytically examine the channel parameters for BFDM/OQAMãand derive their second-order statistics.
A Simple Regenerative Repeating Process for Broadband Communication Satellite
- T. Yamazato, A. Ogawa
- AIAA International Communications Satellite Systems Conference (ICSSC), MOD-1-1, Rome, Italy
- 2005幎9æ
- In this paper, we focus on relay process of broadband communication satellite. We omit the demodulation, error decoding and re-encoding process at the satellite. Just store the received signal as it is and then forward it to the destination in which the information is extracted from the header. We discuss the issue of analog-to-digital converter for this relay process. For given quantization level, reduction of signal accuracy can improve the transmission rate as we can adopt higher order of QAM. However, the degradation occurred due to the reduction of available quantized bit for accuracy. To overcome this issue, we propose to place the error detection code prior to QAM mapping. Using the status of error detector, it is possible to give an accuracy to the received signal so we can improve the performance by soft decoding.
A New Coded QAM Modulation Scheme for Broadband Satellite Communication
- T. Yamazato, T. Yamaoka, H. Okada, M. Katayama, A. Ogawa
- AIAA International Communications Satellite Systems Conference (ICSSC), MOD-3-3, Rome, Italy
- 2005幎9æ
- In this paper, we propose a new multi-rate coded QAM for broadband satellite communication system. The overall coding rate is (m?2)/2 and Turbo code is adopted. The mapping is similar to bit-interleaved coded modulation (BICM) systems; unlike BICM mapping, we only assign four of Turbo coded bits. This brings a set-partitioning. We also consider the effect of quantization bits. Actually we try to realize high-order QAM by using the available quantization bits, which reduces the signal accuracy so the performance may degrade. As results, our proposed scheme achieve good performance even when the available quantization bits are less.
A MIMO System with Relay Terminals for Reliable Wireless Control
- R. Uchida, H. Okada, T. Yamazato, M. Katayama
- IEEE International Symposium on Personal, Indoor and Mobile Radio Communication (PIMRC), pp.1626-1630, Berlin, Germany
- 2005幎9æ
- In this manuscript, wireless communication system for reliable wireless control of industrial machines in indoor environment is considered. In indoor environment, transmitted signal fluctuates due to fading and shadowing. To combat the fading and shadowing, macro / micro spatial diversity can be used as an effective countermeasure. In this manuscript, macro / micro diversity is achieved by multiple wireless relay terminals, which is convenient in setting and moving the macro diversity branches. In the proposed scheme, channel between the transmitter and the receiver through relay terminals is considered as a MIMO channel and separation of the signals re-transmitted from the relay terminals is not required. This feature makes it possible to have higher order diversity without the cost of bandwidth inefficiency. In numerical examples, the performance of the proposed scheme is evaluated by average frame-error rate and outage probability of frame-error rate. With two relay terminals, the diversity gain of the proposed scheme is about 5-6 dB, which is 1 dB higher than that of conventional macroscopic diversity.
Influence of the Nonlinearity of the ADC in an OFDM Receiver
- M. Sawada, H. Okada, T. Yamazato, and M. Katayama
- 10th International OFDM-Workshop 2005, pp.220-224, Hamburug, Germany
- 2005幎8æ
- This paper discusses the influence of the nonlinearity of an analog-to-digital converter (ADC) in an orthogonal frequency division multiplexing (OFDM) receiver. We evaluate a signal constellation and a bit error rate (BER) performance with the consideration of quantization errors and clippings. As a result, the trade off between the quantization error and the clipping and the optimum range for an ADC input amplitude are shown. In addition, it is shown that the peak to average power ratio (PAPR) of the signal is not a good measure of the BER performance, since the peaks occur only with very low probabilities.
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å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.ITS2005-15, pp.45-49, åå€å±, æ¥æ¬
- 2005幎7æ
- æ¬çš¿ã§ã¯å€æ°ã®æž¬è·çšã¬ãŒããçšããŠãããã¯ãŒã¯ãç¯ãããšã§, é害ç©ã®äœçœ®æšå®ã§åŸãããäœçœ®æšå®ç²ŸåºŠãåäžãããããšãèããïŒè€æ°ã®ã¬ãŒãã§åŸãããæž¬è·å€ãããšã«æ£ç¢ºãªäœçœ®æšå®ãè¡ãããã«ïŒMMSEãçšãããã©ã¡ãŒã¿æšå®ãè¡ã. ãã®MMSEãçšããŠæšå®ãããã©ã¡ãŒã¿, æå°ã«ããç®ç颿°ãšããŠïŒææ³ãæ€èšãã. ãããã®ææ³ã«å¯ŸããŠ, åææ³ã®äœçœ®æšå®ç¹æ§, ãŸã, ã¬ãŒããè€æ°ã«ããã ãšã«ããæå¹æ§ãæ¯èŒ, è©äŸ¡ããããã«ã³ã³ãã¥ãŒã¿ã·ãã¥ã¬ãŒã·ã§ã³ãè¡ã£ã.
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å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.SR2005-34, pp.91-96, 暪é è³
- 2005幎7æ
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- 2005幎6æ
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- æ¥æ¬WebCTãŠãŒã¶ã«ã³ãã¡ã¬ã³ã¹, pp.109-113, æ±äº¬
- 2005幎6æ
- ææ¥ã§ã¯åŠçãããã«å·»ã蟌ã¿åå ããããããåŠç¿ææã®åäžã«éèŠã§ãããšããã€ãã®ç ç©¶ã§ææãããŠãããããã¯ããŠã§ãæŽ»çšææ¥ã«ãããŠãåæ§ã§ããããæ¬å ±åã§ã¯ãæ¥æ¬ã®å€§åŠã«ãããŠåŠçãææ¥ã«å·»ã蟌ã¿åå ããããŠã§ãæŽ»çšææ¥ã®æææ³ã玹ä»ãããå
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Performance Evaluation of Route Coding Scheme in Wireless Multi-hop Networks
- H. Okada, T. Wada, K. Ohuchi, M. Saito, T. Yamazato, M. Katayama
- IEEE Vehicular Technology Conference (VTC-Spring), pp.3092-3096, Stockholm
- 2005幎6æ
- Wireless multi-hop networks have been much attention for the future generation mobile communication systems. Due to the possibility of flexible construction in the wireless multi-hop networks, multiple routes from a source node to a destination node can be established. In this paper, we propose the route coding scheme in the wireless multi-hop networks. In the proposed scheme, a packeted data sequence is encoded by the convolutional code at the source node. Each digit of the code word is assigned to sub-packets on multiple routes. At the intermediate nodes, the sub-packets are regenerated-relayed to the next node. The sub-packets transmitted via multiple routes are decoded by the Viterbi decoder with the modified metric computation at the destination node. We also evaluate the system performance, and clarify the improvement of the packet error rate by the proposed scheme. Furthermore, we investigate the influence of the route loss due to topological change or recognizing failure.
Application of Successive Interference Cancellation to a Packet-Recognition/Code-Acquisition Scheme in CDMA Unslotted ALOHA Systems
- Y. Tadokoro, H. Okada, T. Yamazato, M. Katayama
- IEICE Transactions on Fundamentals, vol.E88-A,no.6, pp.1605-1612
- 2005幎6æ
- Packet-recognition/code-acquisition (PR/CA) is one of the most important issues in packet communication systems. In a CDMA Unslotted ALOHA system, Multiple Access Interference (MAI) may bring about error in PR/CA. The MAI mainly stems from already recognized packets and newly arriving packets under the execution of PR/CA. This characteristic of asynchronous transmission in CDMA U-ALOHA systems implies that only one or a few packets arrive at the receiver within a short interval of a execution. Furthermore, newly arriving packets are recognized and code-acquired by using a short preamble part. Consequently, the MAI from the packets under the execution of the PR/CA will be small. Focusing on that point, this paper proposes applying the IC scheme in order to suppress the MAI from the already recognized and code-acquired packets. A performance evaluation demonstrates that such an application is valid due to the small amount of MAI from the packets under the execution of PR/CA. In addition, we demonstrates that the scheme reduces false recognition rather than mis-recognition. Such a scheme improves the performance of not only PR/CA, but also the throughput.
ç¡ç·ãã«ãããããããã¯ãŒã¯äžã®ãªã¢ã«ã¿ã€ã éä¿¡ã«ãããè€æ°çµè·¯ãã±ããåææ³ã®æ§èœè§£æ
- 平山泰åŒïŒå²¡ç°åïŒå±±éæ¬ä¹ïŒçå±±æ£æ
- 第7åYRPç§»åäœéä¿¡ç£åŠå®äº€æµã·ã³ããžãŠã 2005ïŒpp. 92--93, 暪é è³ãªãµãŒãããŒã¯
- 2005幎6æ
Evaluation of the Channel Parameter Statistics for BFDM/OQAM System in Multipath Time-Varying Channels
- B. Mongol, H. Okada, T. Yamazato, M. Katayama
- Technical Report of IEICE, vol.RCS2005-33, pp.35-40, Nagoya
- 2005幎6æ
- Recently, there has been increased interest in using Orthogonal Frequency Division Modulation (OFDM) systems in rapidly time-varying multipath environment. The performance of the systems in such time-frequency dispersive channels, depends critically on the time-frequency localization of the transmitter pulse. Biorthogonal Frequency Division Multiplexing based on Offset QAM (BFDM/OQAM) is attractive modulation method since it allows time-frequency well-localized pulses at critical sampling (i.e. maximum spectral efficiency). In this paper we consider BFDM/OQAM system with Gaussian transmitter pulse and evaluate channel parameter statistics in multipath time-varying channels.
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å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.RCS2005-28, pp.7-12, åå€å±å€§åŠïŒåå€å±
- 2005幎6æ
- å·¥å Žã®ç£æ¥æ©åšãªã©ã«å¯ŸããŠä¿¡é Œæ§ã®é«ãç¡ç·å¶åŸ¡ãå®çŸããããã®ç¡ç·éä¿¡ã·ã¹ãã ã®æ€èšãè¡ãïŒå®€å
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Target position estimation using MMSE for UWB IPCP receivers
- H. Hatano, T. Yamazato, H. Okada, M. Katayama
- 5th International Conference on ITS Telecommunications, pp.131-134, Brest, France
- 2005幎6æ
- In this work, we present target position estimation methods using minimum mean-square error (MMSE) algorithm for short-range radar systems. We consider UWB IPCP (inter-period correlation processor) receiver and improve target position accuracy by using a set of measured ranges. Depend on how we set the objective functions for MMSE, we propose three methods. And we evaluate the performance of position estimations using computer simulations.
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å ±éä¿¡åŠäŒè«æèª, vol.J88-A, no.6, pp.739-750
- 2005幎6æ
- ãã±ããéä¿¡ã·ã¹ãã ã§ã¯é信倱æãšãªã£ããã±ããã¯åéãããã, é信倱æãšãªã£ããã±ããã®å°€åºŠæ
å ±ãå©çšãããš, åéãã±ããã«å¯Ÿãã埩調ãå¹²æžé€å»ã®æäœãããæ£ç¢ºã«è¡ãäºãã§ãã. ããã§, ãã®ãããªåéãã€ããŒã·ããå©çšããå¹²æžé€å»æ³ã幟ã€ãææ¡ãããŠãã. ããããããã®ææ³ã§ã¯, å¹²æžé€å»ã®ã¢ã«ãŽãªãºã ã¯åŸæ¥ã®ãã®ãšåäžã§ãã, é信倱æãšãªã£ããã±ããã®æŽåãã£ã«ã¿åºåãå¹²æžé€å»åšã®åºåã«ãããŠåæããã®ã¿ã§ãã. æ¬ç ç©¶ã§ã¯, é信倱æãã±ããã®å°€åºŠæ
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å ±éä¿¡åŠäŒæè¡ç ç©¶å ±å, vol.SAT2005-9, pp.19-23, 沌接
- 2005幎6æ
- æ¬æç®ã§ã¯, ã¡ããªãã¯èšç®ã»å€èª¿æ¹åŒã®å€æŽã容æã§, 笊å·åå©åŸã®åååŸãããå¯å€ã¬ãŒã笊å·åQAMãææ¡ãã. ãŸã, ãã®èª€ãçç¹æ§ãšéååãããã®é¢ä¿ãæããã«ãã.
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