The development history of mobile communication
The history of mobile communications can be traced back to nineteenth Century. In 1864, Maxwell proved the existence of electromagnetic waves in theory. In 1876 Hertz experiments confirmed the existence of electromagnetic waves. In 1896 Marconi succeeded in the 14.4 km communication test in Britain, and the world entered a new era of radio communication. Mobile communications in the modern sense began in the early 1920s. The development of modern communication technology has gone through five stages since the 20s of last century. From the mid 60s of last century to the middle of 70s, the fourth phase is the vigorous development period of mobile communication. 1G also started in this period.
The development of 1G
At the end of 1978, the Baer laboratory developed the advanced mobile phone system (AMPS) and built a cellular mobile communication network, which greatly improved the system capacity. In 1976, Motorola Engineer Martin Cooper first applied radio to mobile phones. In the same year, the International Radio Conference approved the 800/900 MHz frequency allocation scheme for mobile phones. Since then, in the middle of the 1980s, many countries have begun to build the first generation mobile communication system, 1G, based on frequency division multiplexing (FDMA) and analog modulation technology. However, because of the analog technology, the capacity of the 1G system is very limited. In addition, security and interference also have big problems. In addition, the 1G system's deficiency makes it impossible for it to be popularized and applied on a large scale, and the price is more expensive, a symbol of the luxury and wealth of the time. I believe people who have experienced that era remember that the dress up of windbreaker, sunglasses and cell phone was very stylish in China in the 90s of last century. At the same time, the various countries' self governance also makes the technical standards of 1G different, that is, only "national standards", without "international standards", international roaming has become a prominent problem.
The development of 2G
Coming into the twenty-first Century, communication technology has also entered the era of 2G. Unlike 1G, 2G is using digital transmission technology. This greatly improves the secrecy of communication transmission. 2G technology can be basically cut into two types, one is based on the development of TDMA and GSM is represented, the other is a CDMA specification, a Multiplexing form. With the development of 2G technology, mobile phones have become popular in people's lives. Although the price is still more expensive, it is no longer a luxury. NOKIA 3110, Motorola StarTAC and other classic models have become memories of a generation.
The development of 2G to 3G is not as smooth as 1G to 2G. Because 3G is a considerable project, it is impossible to connect directly to 3G from 2G, so there is a convergence technology between 2G and 3G -- 2.5G. We know HSCSD, WAP, EDGE, Bluetooth (Bluetooth), EPOC and other technologies are 2.5G technology. 2.5G function is usually related to GPRS technology, and GPRS technology is a transitional technology based on GSM. The introduction of GPRS marks the most significant step in the history of GSM development. GPRS provides a connection between mobile users and data networks to provide high-speed wireless IP and X.25 packet data access services for mobile users. Compared with 2G services, 2.5G wireless technology can provide higher speed and more functions.
The development of 3G
With the development of mobile network, people demand for the speed of data transmission day by day, and the transmission speed of 2G network 10 KB per second is obviously unable to meet the requirements of people. So 3G, a high-speed mobile data transmission technology, came into being. At present, there are 3 standards for 3G: CDMA2000, WCDMA and TD-SCDMA. China supports the ITU to determine three wireless interface standards, namely, China Telecom's CDMA2000, China Unicom's WCDMA, and China Mobile's TD-SCDMA. It can be said that the development of 3G has further promoted the development of smart phones, because the transmission speed of 3G can reach hundreds of KB per second. Through 3G, people can browse the computer web page directly, send and receive mail, make video calls, watch live broadcast and so on. It also leads to the assumption that 3G phone can replace PC.
The development of 4G
As an extension of 3G, 4G has been well known in recent years. In March 2008, a set of requirements for 4G standards was designated in the International Telecommunication Union Radio Communications Department (ITU-R), named the IMT-Advanced specification, and the peak speed of setting the 4G service required to reach 100 Mbit in high-speed mobile communications, such as on trains and cars. /s, fixed or low speed mobile communications (such as pedestrians and fixed point Internet users) reached 1 Gbit/s. The technology includes two forms of TD-LTE and FDD-LTE (in strict sense, LTE is only 3.9G, although it is publicized as 4G wireless standard, but it has not been recognized by 3GPP as the next generation of wireless communication standard IMT-Advanced described by the International Telecommunication Union, so it has not yet reached the standard of 4G in strict sense. Compared with the previous generations, the 4G system does not support the traditional circuit switched telephone service, but the whole Internet Protocol (IP) communication. 4G will provide users with faster speed and more users' needs.
The development of 5G
In February 2013, the European Union announced that it would allocate 50 million euros to speed up the development of 5G mobile technology, and plans to launch a mature standard by 2020. In May 8, 2014, NTT DoCoMo, a Japanese telecom operator, officially announced that it would work together with six vendors such as Ericsson, Nokia, Samsung and other manufacturers to start testing the 5G network. The outdoor test is expected to start in 2015 and is expected to begin operation in 2020. In March 1, 2015, the British Daily Mail reported that the UK has successfully developed the 5G network and carried out a data test for 100 meters, and said it was put into public testing in 2018 and was officially launched in 2020. So 2020 was also seen by the industry as a time when 5G was officially launched, but a few days ago, the US mobile operator Verizon wireless announced that it would start to try the 5G network in 2016 and be fully commercially available in some cities in the United States in 2017. Although it has been rebutted by rival AT&T, it is no doubt that it is a sign of people's longing for 5G.
The fundamental driving force of mobile communications from the 1G analog communication system to the digital 2G, to the 3G, the 4G and the future 5G is the constant pursuit of better communication technology. It is people's pursuit of better and faster communication that leads to the continuous progress of communication technology and scientific development.