关键词: 移动通信, 卫星轨道, 频率分配, 发展趋势

Abstract: Personal Communications Systems(PCS)are made of independently developing concepts.Now in the 1990's it have been growing in using orbits other than the geostationary orbit for telecommunications satellites.It is the best approach to use the Low Earth Orbit(LEO) satellites.The use of LEO satellites will be in a manner similar to that proposed for extension of cellular networks and offer many of the same services.The evolution of mobile communications satellite is reyiewed in this paper.A perspective on future networks of low earth orbit satellite is presented, along with conclusion remarks on legal, administrative problems.This paper describes the functional structure of PCS. Some main technical features of several LEO networks are presented in the table for comparison.