In 1998, he gave a half-day tutorial entitled "Introduction to CDMA ALOHA" at the IEEE GLOBECOM held in Sydney, Australia. In 2006, he received the IEEE Communication Society's Best Tutorial Paper Award. He served as the co-chair of the Wireless Communication Symposia of the IEEE ICC 2009 and is the co-chair of Selected Areas in Communication Symposia of the IEEE ICC 2011. From 2008 to 2010, he served as the chair of the Satellite and Space Communication Technical Committee of the IEEE Communication Society. In 2011, he gave a half-day tutorial entitled "Visible Light Communication" at the IEEE ICC 2011 held in Kyoto, Japan. In addition, he served as the editor-in-chief of the Japanese Section of IEICE Transactions on Communications from 2009 to 2011. From 2016 to 2017, he was the Director of the Asia/Pacific Board, the IEEE Communication Society. He co-chaired the 8th and 9th IEEE GLOBECOM Workshop on Optical Wireless Communications (OWC'18 and OWC'20). In addition, he was the Chair of the IEICE Communication Society Editorial Board from 2020 to 2021. Currently he is the Chair of IEICE Tokai Section and the Director of IEICE Communication Society Journal Publication.
His research interests include visible light communication, ITS, and stochastic resonance.