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System Classification of Mobile Communication

Mobile communication refers to communication between mobile bodies or communication between mobile bodies and fixed bodies. The moving body may be a person, or may be an object in a moving state such as a car, a train, a ship, or an airplane. The history of mobile communications can be traced back to the 19th century. In 1864, Maxwell theoretically proved the existence of electromagnetic waves; in 1876 Hertz confirmed the existence of electromagnetic waves through experiments; in 1900, Marconi et al. made use of electromagnetic waves to achieve long-distance radio communications. Since then, the world has entered a new era of radio communications. .

Mobile communications in the modern sense began in the early 1920s. The landmark technology during this period was the in-car radio system used by the Detroit police in the United States. It was said to have been invented by Purdue University students. In the mid-1970s, Bell Labs proposed the theory of community system and cellular networking, which are landmarks in the history of mobile communications. It opened the way for the widespread use of mobile communication systems worldwide. Since then, mobile communications have begun. Really melt people's lives.

There are mainly three kinds of classification methods for mobile communication: one is based on the environment in which the device is used, one is based on the object of the device service, and the other is mainly based on the mobile communication system. This mainly analyzes the third taxonomy.

According to the classification of mobile communication systems, mobile communication can be mainly divided into trunking mobile communication, cellular mobile communication, cordless telephone and satellite mobile communication.

Cluster Mobile Communication

Cluster mobile communication, also known as large-area system mobile communication, is a more economical and more flexible mobile communication system developed in the 1970s. It is a high-level development stage of traditional private radio dispatch networks. The trunking mobile communication system is vividly called a user program-controlled switchboard. It applies the working mode of the wireline telephone trunk to a radio communication system, and distributes the limited channels dynamically, automatically, rapidly, and optimally to the entire system. All users, in order to maximize the use of the frequency resources of the entire system's channel, and the use of switching technology and computer technology to provide all users of the system with strong grouping capabilities.

Cluster mobile communication is suitable for group dispatching in various professional departments (such as troops, public security, fire fighting, traffic, flood prevention, power, railway, finance, etc.). The United States, Britain, France, Germany, Japan, the Nordic countries, Canada and Australia, China and other countries have extensively developed and used this system. In the 1980s and 1990s, this kind of communication technology once occupied a large proportion in the field of private radio communications, becoming an advanced communication system that goes hand in hand with cellular mobile communications.

Cellular mobile communications

Cellular mobile communication is also called cell-based mobile communication. It adopts a cellular wireless networking method and connects a terminal and a network device through a wireless channel, thereby realizing user's mutual communication in activities. It has the function of handoff and automatic roaming across local networks. It can divide the entire service area into many cells. Each cell is equipped with a base station and is responsible for the communication and control of each mobile station in the cell. Each base station communicates with each other through a mobile switching center. Contact and connect with the local office. Common cellular mobile communication systems can be classified into three types according to their functions, namely macrocells, microcells, and smart cells.

Satellite mobile communications

Satellite mobile communications mainly use mobile satellites to transmit signals. The use of geostationary satellites or medium- and low-orbit satellites as relays and stations to achieve regional and global mobile communications is called satellite mobile communications.

The complete satellite mobile communication system generally consists of three parts: the first part is the communication satellite, which is generally composed of one or more satellites; the second part is the ground control station, including the system control center and several public telephone exchange networks and Mobile users connected to the transfer station; the third part is the mobile user communication terminal, this communication terminal can be divided into car, shipborne, onboard terminals and handhelds. Recalling the development of mobile satellite communications, as early as June 1990, Motorola Corporation of the United States took the lead in launching the “Plutonium” system plan for global personal mobile communications, and prepared to use 66 low-orbit satellite networks to implement any two mobile users on Earth. Communication between. Since then, foreign countries have also launched more than 10 kinds of global or regional satellite mobile communication programs, such as the United States, "Global Star" system, "Odyssey" system, the International Maritime Satellite Organization "21st Century Plan" and so on.

Satellite mobile communications have the characteristics of strong mobility, large coverage (including areas where the oceans and land (including polar and any terrain) and ground infrastructure are not suitable), high reliability, and high transmission efficiency, and are currently the only ones that are globally user-friendly. The complete peer-to-peer communication system has a wide range of applications, covering domestic and international communications as well as civil and military communications.