What is the History of the Cellular Phone?

Cellular: In order to accommodate a large number of users, a geographical area can be divided into many cells. Instead of using a single high-power transmitter, each cell is served by a low-power base station. Because the range that these base stations can affect is relatively limited, the same spectrum can be reused in another cell far from a certain distance. The combination of frequency reuse and handoff operation forms the main body of the cell (cellular) concept.

Honeycomb is a cost-effective structural method. The English name of a cellular phone is Cell phone. Cell has the meaning of a cell. It is not difficult to imagine a model of him: infinite division. In architecture, the hive is a cost-effective way to structure,

According to the position where the positioning calculation is performed and the positioning result is obtained, and where the positioning result is applied, the cellular phone positioning system can be divided into: an autonomous positioning system, a remote positioning system, an indirect autonomous positioning system, and an indirect remote positioning system. In an autonomous positioning system, the MS can receive information from surrounding base stations (BTS) and make appropriate signal parameter measurements, and use these measurements to calculate the MS's location. In the remote positioning system, the signal sent by the MS is received and measured by one or more receivers, and the measured value is sent to the positioning center (LC) for calculation to obtain the positioning value of the MS. These positioning information can be applied in the LC and also Can be passed to other system applications, such as

In order to meet the needs of people's mobile communications, with the in-depth study of electromagnetic waves and the advent of large-scale integrated circuits, mobile phones were first manufactured. It is mainly composed of a receiver, a control component, an antenna, and a power supply. In addition to the microphone and earphones on the handset, there are digital and alphanumeric displays, control keys and dial keys. The control component has many important functions such as modulation and demodulation. Because the handheld mobile phone is used in mobile, the required power is supplied by its own battery. At that time, nickel-cadmium batteries were used, which could be recharged repeatedly.

In the early 1970s, after Bell Labs proposed the concept of cell coverage in cellular systems and related theories, it quickly developed and quickly entered the practical stage. In a cellular network, each geographic area (usually a large and medium-sized city and its suburbs) has multiple base stations and is controlled by a mobile phone switch. ^[1]

status quo

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.

China began to use analog cellular telephone communication in 1987. In November 1987, the first mobile telephone office was opened in Guangzhou. The development of China's cellular mobile communication technology has roughly gone through three major development processes: 1. In the development of the first generation of cellular mobile communication technology, which is also the 1G era, the most prominent contribution is the introduction of mobile communication concepts and basic technologies , Which has improved the level of frequency technology and ensured the capacity of the equipment. In the 2.2G era, a certain number of digital services were added on the basis of the original voice technology. The start of digital services started a new stage of praise for cellular mobile communication technology; 3.3G technology adds a number of functions to the original technology, and has achieved great strides in business scope and transmission capabilities ^[2] .

Cellular networking ideas

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 division and low-power transmission

2.Multi-channel public and handover

3.Frequency reuse

future development

In the last few years of the development of the 20th century, mobile communication technology and the Internet have become the world's fastest-growing markets, the largest market appreciation space, and the most attractive market areas. Its rapid development is unpredictable by anyone. With the development of the times and the development of science and technology, the demand for mobile communication technology and the Internet is rising sharply. Therefore, the combination of mobile and Internet has become an inevitable trend in historical development, and it is also a new requirement for the development of mobile communication technology given by the times ^[3] .