Tohoku University. Research Profiles


Message Transmission without Cellular Coverage, “Relay-by-Smartphone"



Our technology provides the necessary method for sending messages even when the physical infrastructure is not available. The technology utilizes common smartphone WiFi functionality to send message in a multi-hop fashion. Thus it is possible to send message to people further away. Our technology has been designed to be based on Delay-Tolerant Networks (DTN), but the technical key idea is the combination of DTN and Mobile Adhoc Network (MANET), which can improve the message delivery in an area with high population density or where mobility are fixed such as evacuation center.

Targeted Application(s)/Industry

This technology can be used to distribute information during emergency situation such as after disaster. In addition, it is possible to provide additional services such as advertisement within shopping areas, distribution of coupons, exchange of information within small group during public events or uses as transceiver during group hiking. There is also possibility of using this technology to provide communications service in developing nations.


Graduate School of Information Sciences

KATO Nei , Professor
Doctor of Engineering


Related Information

1. Hiroki Nishiyama, Masaya Ito, and Nei Kato, "Relay-by-Smartphone: Realizing Multi-Hop Device-to-Device Communications", IEEE Communications Magazine, vol. 52, no. 4, pp. 56-65, Apr. 2014.
2. Masaya Ito, Hiroki Nishiyama, and Nei Kato, "A Novel Communication Mode Selection Technology for DTN over MANET Architecture" IEEE ICNC 2014 Feb 2014.
3. Yuichi Kawamoto, Hiroki Nishiyama, and Nei Kato, "Toward Terminal-to-Terminal Communication Networks: A Hybrid MANET and DTN Approach" IEEE ETPSC'2013 Sep. 2013.

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