Multi-Mode Portable VSAT for Disaster-Resilient Wireless Networks

In the event of large scale disaster such as the great east Japan earthquake, we completely lose the terrestrial communication infrastructure and have no measure to call the outside of the disaster area. Satellite communication is only an exception and can be usable in such a situation. In this project, funded by the Ministry of Internal Affairs and Communication (MIC), Japan, we have developed a portable multi-mode very small aperture terminal (VSAT) system for disaster-resilient wireless networks. In order to realize multi-mode functionality, the VSAT indoor unit (IDU) has been developed based on the software defined radio (SDR) technology. It can be used as a wireless-local area network (W-LAN) router which is connected to 3rd generation (3G) cellular/Long Term Evolution (LTE) in the normal situation. In the case of the disaster, the connection will be changed to the satellite communication route and will provide the Internet environment to the evacuees nearby this VSAT IDU. It can also provide the dual-connection using SDR technology; one is Internet connection via private VSAT network (EsBird, provided by SKY Perfect JSAT) and another is the local authorities satellite communications network system connection via Local Authorities Satellite Communications Organization (LASCOM) network By combining the automatic uplink access test (UAT) outdoor unit (ODU), a set of IDU and ODU can be easily carried and installed by the evacuees and it will operate more than a week by the electric power supplied from a hybrid vehicle (HV) with a fill-up gas tank. In this project, digital front-end technologies for VSAT's transceiver has also been developed. The demonstration of developed VSAT was carried out in the disaster stricken area.