The gap filler technology for mobile satellite system

Satellite mobile communication systems have rapidly come into widespread use and user have begun to require high speed multimedia services in mobile environments in any place; even if high speed train. In response to these demands, mobile satellite communication system is the key solution to provide high speed multimedia services in high speed train. Nowadays the high speed portable system has been developed for example WiMAX, Wibro and so on. But these system can't provide high speed internet services because of the train speed. To figure out this problem, mobile satellite communication fits this environment. And mobile satellite communication system can play in a role of backhaul for WiMAX or Wibro system. But there is disadvantage in mobile satellite communication system, signal may suffer shadowing, power arche, trees and tunnels. Shadowing, power arches and trees degrades the network performance, it can be overcomed by use of packet FEC. But it is difficult to provide internet service in tunnel. To figure out this problem, we adopt the gap filler system which relay from/to satellite to/from terminal in tunnel. In this paper we introduce and compare the various types of gap filler, transparent and non-transparent types and finally how our gap filler system is configured.