Analysis of the development history of wireless communication

Abstract: At present, the field of mobile and wireless technology is in a period of rapid development. Various innovative mobile and wireless technologies are constantly emerging and rapidly entering commercial use. The mobile and wireless application market is extremely active, and mobile and wireless technologies themselves are also evolving rapidly. Continuous innovation. The future development trend of wireless communication is as follows: From the perspective of large-scale public mobile communication, 3G or super 3G technology will be dominant, thus forming a wide and seamless coverage of the world; while WLAN, WiMAX, UWB and other broadband access technologies will Because of its own different technical characteristics, it forms an effective complement to the public mobile communication network in different coverage areas or application areas.
Keywords: wireless communication, cellular network, development status, trend,
development history of wireless communication
, wireless communication has also developed from a fixed mode to a mobile mode, and the development of mobile communication has experienced about five stages: the
first stage is from the early 1920s to the early 1950s , mainly used in ships and military, using short-wave frequency and electronic tube technology, until the end of this stage, the 150MHZVHF simplex car public mobile phone system MTS appeared.
The second stage is from the 1950s to the 1960s. At this time, the frequency band was extended to UHF450MHZ, and the device technology has transitioned to semiconductors. Most of them are dedicated systems in the mobile environment, and the connection between mobile phones and public telephone networks has been solved.
The third stage is the extension of the frequency band to 800MHZ from the early 1970s to the early 1980s. The Bell Research Institute of the United States proposed the concept of a cellular system and carried out AMPS experiments in the late 1970s.
The fourth stage is from the early 1980s to the mid-1990s, which is the stage of the rise and great development of the second generation of digital mobile communications, and gradually moved towards the direction of personal communication services; at this time, D-AMPS, TACS, ETACS, GSM/DCS, cdmaOne, PDC, PHS, DECT, PACS, PCS and other systems and business operations, the frequency band is extended to 900MHZ~1.9GHZ, and in addition to public cellular phone communication systems, wireless paging systems, cordless phone systems, trunking systems, centerless All kinds of mobile communication means, such as multi-channel site selection mobile communication system, have emerged simultaneously to meet the needs of the user's market and have shown their special abilities.
The fifth stage is from the mid-1990s to the present. With the development of data communication and multimedia business requirements, the third generation of mobile communication that meets the needs of mobile data, mobile computing and mobile multimedia operations began to emerge. Its global standardization and corresponding integration work and prototype development And the field test work is advancing rapidly, including the smooth transition from the second generation to the third generation of mobile communications. For the third-generation mobile TMT-2000, they have participated in the formulation of standards. After many integration efforts, the 18th meeting of ITU-RTG8/1 held in Helsinki, Finland, from October 25 to November 5, 1999, five types of RTT technical standards A total of 6 schemes became the final result. China's TD-SCDMA program has also become one of them.
In addition, the wireless application protocol (WAP) and the wireless connection technology Bluetooth (Bluetooth) have been produced for continuous Internet mobile browsing applications. From the network point of view, the access network can be divided into wired access network and wireless access network, optical cable coaxial hybrid access network, copper cable, twisted pair, telephone (usually copper wire) access network, etc. ; Wireless access technology is a new technology field that has developed rapidly in recent years. It has produced a major leap in concept, that is, it does not need cable-like physical transmission media and uses wireless transmission methods to replace part of the access network or even access the network. All of them, so as to achieve the purpose of reducing cost, improving flexibility and extending transmission distance. There are many types of wireless access networks, such as mobile health systems, cellular mobile communication systems, trunking communication systems, point-to-multipoint microwave communication systems, microwave cellular wireless local access systems (PHS, PAS, PACS, DECT), etc. Access technologies within a short distance mainly include Bluetooth (Bluetooth), infrared, DECT, IEEE802.11 and shared wireless access protocol (SWAP)/HomeRF and other systems. Following the wide area network (WAN, Wind, AreaNetwork or metropolitan area network, MAN, MetropolitanAreaNetwork), local area network (LAN, LocalAreaNetwork), people have recently proposed "wireless personal area network" (WPAN, WirelessPersonalAreaNetwork). This new concept elevates small-scale applications to the level of network theory. In a short period of time, WPAN has become a new focus of attention. The WPAN research group evolved into IEEE802.5 (WPAN Working Group, established in March 1999), a special working group of IEEE, which was established in March 1999. its degree of attention.
In order to promote the development of Bluetooth, the standard of Bluetooth is non-patented. Bluetooth has become a new hot spot in the field of communication at present, and it is expected to become an international standard for small-scale wireless multimedia communication in the near future. In short, the future of wireless communication technology is bright.
The future trend of wireless communication technology
The main trend of wireless communication technology development in the future is broadband, packetization, comprehensive economics, and personalization. The main features are reflected in the following aspects:
(1) Broadband is one of the important directions for the development of communication and information technology. With the further development of optical fiber transmission technology and high-throughput network nodes, the broadbandization of wired networks is in full swing around the world, and wireless communication technology is also evolving in the direction of wireless access to broadband, and the wireless transmission rate will increase from The 9.6Kbit/s of the second generation system develops towards the highest rate of 2Mbit/s of the third generation mobile communication system.
(2) The core network is integrated and the access network is diversified. The structural model of the future information network will change to the core network/access network. The packetization and broadbandization of the network will make it possible to transmit multiple business information on the same core network. The integration of the network and the gradual opening of the control and market The need for competition will further promote the integration of traditional telecommunication networks and emerging computer networks. The access network is the part with the most development potential in the communication information network. In the future, the network can access the core network through different access devices such as fixed access, mobile cellular access, and wireless local loop access to realize various functions required by users. kind of business. Technically, the integration of different services such as fixed and mobile communications, especially the advent of the Wireless Application Protocol (WAP), will greatly promote the development of wireless data services and further promote the integration of mobile services and IP services.
(3) Personalization of information is one of the main directions for the further development of the information industry at the beginning of the next century. The mobile IP is an important technical means to realize personalization of information in the future. The realization of various IP applications and mobile IP technology on mobile phones is gradually becoming one of the focuses of people's attention. The combination of mobile intelligent network technology and IP technology will further promote the trend of global personal communication.
(4) The structure of the mobile communication network is undergoing a profound change. With the formation of the dominance of data traffic in the network, the transition from the existing circuit switching network to the IP network is irresistible, and IP technology will become the core of the future network The key technology, the IP protocol will become the dominant communication protocol of the telecommunication network. With the introduction of general packet radio service (GPRS) in mobile communication, users will send and receive data in the end-to-end packet transmission mode, breaking the traditional data access mode. Based on IP networking, the practice of IP application in the mobile backbone network began.
In addition to traditional public mobile communications, recent research and applications in the global broadband wireless access field are very active, and hotspots continue to emerge, bringing fresh air to the wireless communications industry. This includes broadband fixed wireless access technology, WLAN technology, WiMAX technology, UWB technology, etc., presenting a situation where a hundred flowers are blooming. The emergence and development of these technologies have injected vitality into the entire wireless communication industry.
WiMAX, the new darling of broadband wireless technology
According to data, "WiMAX" has become the most searched communication keyword on the Internet recently. This technology has become the new darling of the wireless industry because of its long-distance coverage and high bandwidth characteristics.
The full name of WiMAX is World Interoperability for Microwave Access, that is, the global interoperability system for microwave access, and its technical standard is IEEE 802.16. WiMAX has also organized its own alliance. At present, this alliance has developed dozens of members. The alliance is led by Intel, and my country's ZTE is also among them. The goal of WiMAX is to facilitate the application of IEEE 802.16.
The advantages of WiMAX over Wi-Fi are mainly reflected in the fact that Wi-Fi solves the access problem of wireless local area network, while WiMAX solves the problem of wireless metropolitan area network. Wi-Fi can only transmit an Internet connection signal as far as 300 feet, and WiMAX can transmit the signal as far as 31 miles. Wi-Fi network connection speed is 54 megabits per second, while WiMAX is 70 megabits per second. Some experts believe that the coverage and transmission speed of WiMAX will pose a threat to 3G. Advantages in various aspects such as cost make people in the industry regard WiMAX technology as a technology that breaks the industrial pattern.
Recently, British Telecom (BT), France Telecom, Qwest Communications, Reliance Telecom and XO Communications have joined the WiMAX Forum. At present, the WiMAX Forum has 98 members, and operators account for 25%.
Ultra Wide Band Wireless Access Technology UWB
UWB is a time-domain communication technology that uses ultra-short-period pulses for modulation, and sends the signal directly as 0 or 1 without using a carrier, which is completely different from the previous wireless communication. The signal generated by pulse modulation is an ultra-wideband signal with extremely low spectral density. The center frequency of the signal is between 650MHz and 5GHz, and the average power is in the order of submilliwatts. It has strong anti-interference and multipath capabilities, and has multiple available channels. . Compared with the CDMA system, the time domain communication system is simple in structure and relatively low in cost. UWB technology has the remarkable characteristics of high speed, low cost and low power consumption.
The most striking feature of UWB is its high data transfer rate. Xtreme Spectrum Company predicts that the products they will develop will have the ability to transmit about 100Mbps within 10 meters, and Intel has set the goal at 500Mbps.
Trend Analysis For UWB technology, we should look at it this way. With its unique speed and special application range, it will also occupy a place in the field of wireless communication. Because of its high speed and narrow coverage, it is very suitable for building a high-speed information network for families. It has a certain impact on Bluetooth technology, but it has little threat to current mobile technology, WLAN and other technologies, and can even become a good supplement to it.
  The mobile network accelerates the evolution of
     HSDPA to broadband faster than expected commercial speed. The CEO of GSMA said that the commercial progress of HSPA is three years faster than that of GSM and WCDMA. There are three main reasons: the pressure of WiMAX; the vigorous development of Internet services; the services provided by the initial version of 3G are not much different from those of 2G.
    The mobile communication network is rapidly becoming a broadband Internet service platform. The CEO of Vodafone believes that the application of the Internet should quickly enter the mobile network, and they have begun to cooperate with Google, Myspace and YouTube. LTE (Long Term Evolution Project) standardization and research and development speed is accelerating. At the same time, WiMAX improves the update speed of cellular mobile communication technology. After the introduction of 802.16 series WiMAX in early 2004, a new round of technological competition began in the entire wireless communication field, which accelerated the evolution of cellular mobile communication technology.
     3GPP and 3GPP2 started the standardization of 3G evolution technology E3G at the end of 2004 and early 2005 respectively. Among them, 3GPP launched the LTE plan, and the technical requirements proposed are: to achieve a downlink rate of 100Mbit/s and an uplink rate of 50Mbit/s, and the spectral efficiency is 2 to 4 times higher than that of the R6 version, which can better support IP transmission services and lower costs. 3GPP plans to complete the main parameter research in 2006 and complete the standardization in June 2007. 3GPP2 proposes the radio interface evolution (AIE) plan. AIE is divided into two phases. The first phase adopts multi-carrier CDMA2000 1xEV-DO technology, and a maximum of 15 carriers are bundled, which can support data services at a rate of 46.5Mbit/s downlink and 27Mbit/s uplink; the second phase uses enhanced The wireless interface will support data services at a rate of 100Mbit/s to 1 Gbit/s in the downlink and 50Mbit/s to 100Mbit/s in the uplink. The first phase was launched in early 2006 and the second phase was completed in April 2007.
    In 2006, WiMAX made substantial progress. The IEEE 802.16m standard will bring wireless data transmission speeds up to 1Gbps, and its launch is of great significance to the future prospects of WiMAX.
     The introduction and promotion of WiMAX, and the start and acceleration of E3G standardization have made the field of wireless mobile communication show a clear trend of broadband and mobile development, that is, broadband wireless access is developing towards mobility, while mobile communication is developing towards broadband.
    Mobile and wireless technologies are evolving towards integration. At
     present, the field of mobile and wireless technology is in a period of rapid development. Various innovative mobile and wireless technologies are emerging and quickly entering commercial use. The mobile and wireless application market is extremely active. Mobile, wireless Wireless technology itself is also constantly innovating in its rapid evolution. Under the general trend of network convergence, various mobile and wireless technologies such as 3G, WiMAX, and WLAN are merging with each other in the evolution.
     Under the general trend of multiple integration, various wireless technologies such as 3G, WiMAX, and WLAN learn from each other in the competition, and new radio frequency technologies, such as MIMO and OFDM technologies, which are adopted by the above wireless technologies at the same time, emerge. At the same time, on the evolution path of cellular mobile communication from 3G to E3G and then to B3G/4G led by ITU and 3GPP/3GPP2, and wireless broadband access led by IEEE from wireless personal area network to wireless local area network, wireless On the road of evolution from the metropolitan area network to the wireless wide area network, the content of the other party has begun to be added. For example, the broadband transmission performance of mobile communication is continuously enhanced, and the roaming performance and security performance of wireless broadband access are constantly enhanced.
     Drawing lessons from the high-speed data transmission characteristics of WiMAX, cellular mobile communications launched LTE, the "3G Long Term Evolution" project, to enhance broadband transmission performance. The establishment of LTE has brought many similarities between the technical lines of the cellular mobile communication system and WiMAX, which is positioned as "low mobility broadband access".
     When cellular mobile communication is learning from WiMAX and WLAN, WiMAX and WLAN are also adding carrier-level security and other content. In terms of security, WiMAX and WLAN will provide different levels of security solutions based on multi-level security policies (WEP, WPA, WPA2, AES, VPN, etc.), so that enterprises and individual users can choose security solutions that meet their needs according to different cost performance. strategy; in terms of roaming capabilities, WiMAX and WLAN are also moving towards greater coverage, from hotspots to hot spots to the entire city; in terms of technology, WiMAX and WLAN will be committed to building IP-based switching technologies and open services platform that makes networks smarter and easier to manage.
     Under the general trend of "wireless + broadband", whether it is cellular mobile communication technology or wireless broadband technologies such as WiMAX and WLAN, they all face the same test: channel multipath fading and spectrum efficiency. Under such circumstances, OFDM and MIMO become the common choice of various wireless technologies. While OFDM solves the problem of multipath fading, it increases the number of carriers, resulting in an increase in system complexity and bandwidth; MIMO can effectively increase the transmission rate of the system and improve spectral efficiency without increasing the system bandwidth. . Therefore, the combination of OFDM and MIMO has become an important force to promote the development of "wireless + broadband".
      In the course of the convergence of various wireless networks, many new business applications continue to emerge. From rich and colorful personal services to rising industry applications; from communication between people to communication between people and machines, and between machines and machines, wireless business applications tend to be diversified. The increasingly diversified wireless business applications show the bright future of the wireless information society.