Evaluation of wireless channel quality for an ad hoc network in the sky, SKYMESH

This paper investigates the statistical characteristics of the wireless channel in an ad hoc network in the sky “SKYMESH,” which is a solution for temporal communication networks in the large-scale natural disasters. SKYMESH consists of balloon nodes, which are located at 50–100 m high over the the ground, and build the wireless network in the air. In this system, line-of-sight (LoS) is kept between balloon nodes, and the disaster area can be covered effectively. Wireless channel quality is quickly changed due to the swinging of balloon nodes. In order to investigate the statistical characteristics of the wireless channel, receive signal strength indicator (RSSI) and swing strength of the balloon nodes is measured in the field experiment at Niigata University in August 2008, and at Yamakoshi, Nagaoka-city in October 2008. As a result, when the angle rate of communication equipments increases, the standard deviation of RSSI in the inter-balloon communications increases. In the communications between the balloon and the ground nodes, long-term statistics is caused by the change of the antenna direction by wind, and short-term statistics is Nakagami-Rice fading environment.