Design of the mitigation information network in urban area

Abstract

In Japan, major earthquakes are predicted to occur in the metropolitan area. In the time of such a disaster, communication systems will play an important role to transfer mitigation information such as instruction for people to move the evacuate area and for contractors to recover city functions. However, mitigation information may be unable to transfer smoothly, because of telecom infrastructure damage and conflicting information. Objective of this research is to clarify system requirements in order to build the mitigation network using wireless LAN systems. Use cases for network design are created based on reports and actions of public organizations when the great East Japan earthquake was happened. We propose the mitigation information network composed of three sub networks; the long-distance wireless LAN for connecting to the backup station in non-disaster area, the midrange wireless LAN for connecting between countermeasures offices, the information gathering and distribution network in disaster area. In order to decide specification of wireless systems and position of antenna, we measure throughput of 2.5GHz and 4.9GHz band between Shinjuku and Hachioji for the long-distance wireless LAN. Also we measure throughput of 4.9GHz band in Nishi-Shinjuku area, where is forest of tall buildings, for the information gathering and distribution network. The mitigation network will be built with these results.