This system is divided into several independent subsystems, each subsystem is a community, and there are communication base stations and mobile stations in the area (referring to handheld mobile phones or notebook computers with communication functions, etc.). A community is a basic unit, and the net formed by these basic units is like a beehive. Because cellular mobile phone is a two-way communication system (which can make and receive calls), it has a complex structure and can be divided into two parts: local telephone network and cellular network. The local telephone office, mobile telephone communication bureau and long-distance telephone office are connected by a large number of large-capacity lines; The mobile phone communication bureau is also connected with the base station through the tie line to control the base station and the equipment for receiving and sending signals (receiver and transmitter for short); A mobile phone (mobile phone or mobile phone) includes a receiver and a transmitter. In this way, the mobile phone and the base station can send and receive each other, that is, the mobile phone can be used to answer and make calls. In addition, when the mobile phone enters a different cell, the channel of the mobile phone will be automatically switched and matched with the base station of the cell.