海上長距離無線LAN通信システムの伝搬特件

摘要

We established the 47.5 kilometer IEEE802.1 lg wireless link between two points which was the longest distance wireless LAN system in Japan. We achieved 4-8 Mbps TCP bandwidth at the link. But there was not enough discussion of such long distance wireless link. So this study was aimed at investigating the propagation characteristics of the long-distance wireless LAN system with experimentally and theoretically. As a result, we proposed the most effective factor of receive signal strength fluctuations to be the variation of reflected wave strength associated with atmospheric refractivity fluctuations.%無線局免許が不要な市販のIEEE802．11g無線LAN装置を用いて伝送距離47．5km，TCP帯域4-8Mbpsの海上無線LAN通信に成功し，無線LAN通信距離の日本記録を達成した．しかし，海上長距離区間における2．4GHz無線LAN通信システムの電波伝搬特性については十分に明らかにされていない．そこで，この区間の伝搬特性について実測値による評価と理論的検証を行い，受信電界強度変動の最大の要因が大気屈折率変動に伴う直接波と海面反射波の伝搬路長の差の変動であることを明らかにした．