What Are Cellular Telecommunications?
Personal digital cellular telecommunication system refers to the mobile communication system used is a cellular mobile telephone system.
- The modern cellular mobile phone system developed in the 1980s is the first generation of mobile communication systems. The first generation of mobile communication systems mainly include AMPS in the United States and TACS in the United Kingdom.
- What our country uses is
Personal Digital Cellular Telecommunications System Cellular Mobile Communications
- Cellular mobile communication is in a dominant position in mobile communication. It is currently the most widely used mobile communication system with the largest number of users and the closest to people's daily life.
- It is characterized by dividing the entire large-scale service area into many cells. Each cell is provided with a base station, which is responsible for the communication and control of each mobile station in the cell. Each base station is connected to each other through a mobile switching center and is connected to the local telephone office.
- Utilizing the characteristics of limited transmission distance of ultra-short radio waves, cells that are away from a certain distance can reuse frequencies, so that frequency resources can be fully utilized.
- Duplex communication refers to a communication method in which both transmitting and receiving radio stations work simultaneously, and information can be transmitted in both directions at the same time. Duplex communication is widely used in cellular mobile communication systems. [2]
Principles of cellular mobile communications in personal digital cellular telecommunication systems
- The modern cellular mobile phone system is based on the rapid development of large-scale integrated circuit technology and uses the most advanced technology in mobile communication research. It has the functions of duplex communication, automatic user handover, and roaming, which greatly facilitates users.
- The first-generation cellular mobile phone system was an analog cellular mobile phone system, which was mainly characterized by transmitting analog signals in an analog manner. The United States, the United Kingdom, and Japan have developed their own systems. In 1975, the United States Federal Communications Commission (FCC) opened the mobile phone market, determined the spectrum of land mobile phone communications and large-capacity cellular mobile phones, and prepared mobile phone investors for use. In 1979, Japan opened the world The first cellular mobile phone network. In fact, the world's first mobile phone communication system was opened in Chicago, the United States in 1978, but the cellular mobile phone later took over. In 1979, after the AMPS analog cellular mobile phone system was tested in Chicago, the United States finally ended in December 1983. Commercialized in the United States. By the end of 1990, there were about 80 countries and regions using cellular mobile phone systems, with more than 10.38 million users, of which the United States had the largest number of mobile phone users, accounting for 49.1% of the world's total users. China began to use analog cellular telephone communication in 1987. In November 1987, the first mobile telephone office was opened in Guangzhou.
- The theory of cellular networking was proposed by Bell Labs. It is a concept inspired by the development of mobile communications and represents a completely different method of constructing mobile communication networks. The purpose of cellular networking is to solve the problems of lack of spectrum, small capacity, poor service quality, and low spectrum utilization of conventional mobile communication systems. The ideas of cellular networking theory are: 1. Cellular system division and low-power transmission 2. Multi-channel common and handover 3. Frequency reuse. [3]