Proposal of Delay Tolerant Network with Cognitive Wireless Network for Disaster Information Network System

If a large scale of disaster occurs such as the East Japan Great Earthquake, there would be some possibility of the informational isolation from others because of the disconnection of communication network or high congestion. In facts, the East Japan Great Earthquake isolated many Japanese coastal resident areas, and the lack of disaster information is considered to affect the speed of rescue, evacuation, and sending life materials. DTN (Delay Tolerant Network) is supposed to be one of the effective methods to transmit significant data even under poor network conditions. However, when DTN is applied to local areas such as the Japanese Northern East coastal cities which were severely damaged by the earthquake, DTN might not work effectively. That is because there are some considerable problems such as fewer roads, cars, and pedestrians than in urban areas. Moreover, the scale of area is likely wider than that of urban areas because it includes many non-residential areas such as rice fields, gardens, and woods. Therefore, it is necessary to consider additional effective functions when DTN is applied for a Disaster Information Network System in local areas. In this paper, DTN with CWN (Cognitive Wireless Network) is proposed for a Disaster Information Network System for the usage of local areas. Then, we consider the actual usage of DTN in local areas, and the simulation of DTN with different wireless network interfaces as held by the GIS data of Taro, Miyako City, Iwate in Japan, a town severely damaged by the East Japan Great Earthquake. The results and future studies are discussed for the DTN usage of Disaster Information Network System in local areas.