Problem analysis and improvement of disaster information network and system from experiences of the great East Japan Earthquake

East Japan Great Earthquake on March 11 in 2011 caused severe damages over the wide area of Northern Japan, and there are many remained problems even now. Information network systems were also severely damaged by the East Japan Great Earthquake, and a robust network has become one of the significant subjects. Compared with the previous major earthquake in Japan such as the Hanshin-Awaji Great Earthquake, the recent highly developed information society brought the different types of problems such as the congestion of cellar phone, the lack of fuels and electricity, and so on. In this paper, the problems of information network systems on East Japan Great Earthquake are analyzed, and these problems are discussed for the improvements of Disaster Information Network and System. Through the experience of the earthquake, the connection of information network is the most important other than throughput or latency for disaster information system. In fact, satellite system, wireless LAN, and cognitive wireless system were useful for the reactivating network connection in the disaster area.