一、移动通信发展概况移动通信是指通信对象之间处于移动状态下的通信,包括固定点与移动对象之间的通信。处于移动状态的通信对象包括陆地上的各种车辆,海上的舰船,空中的飞机及通信卫星等,因而按照活动范围可分为陆上移动通信,海上移动通信及航空移动通信等。其中陆上移动通信由于受地面上地形地物影响,传播情况复杂;而且用户数目多,要求业务种类多,因此成了研究的重点。如各种调度用移动通信,无线电寻呼系统,无绳塞电话及公众移动电话 First, the development of mobile communications Overview Mobile communications refers to the communications between objects in a state of communication, including the fixed point and the communication between mobile objects. Communication objects in the mobile state include various vehicles on land, ships at sea, airplanes and communication satellites in the land, and thus can be classified into land mobile communications, maritime mobile communications and aeronautical mobile communications according to their range of activities. Among them, the land mobile communication is complicated by the terrain and terrain on the ground, and the propagation situation is complicated. Moreover, due to the large number of users and the large variety of services, it has become a research focus. Such as various scheduling mobile communications, radio paging systems, cordless plug phones and public mobile phones