What are the most popular types of wireless access technology at present?
Mobile communication system, mobile communication system from the first generation to the second generation digital analog system, the third generation based on CDMA technology of mobile communication will be commercial, the fourth generation mobile communication systems are in the experiment, after 5 years will be available.
LAN (Wireless) is a product of the combination of computer network and wireless communication technology (WLAN). The utility model has the advantages of flexible networking, convenient expansion, compatibility with a plurality of network standards, wide application, etc., and is capable of solving the problems caused by the difficult wiring of the cable network, etc., and is free from cable binding and moving. WLAN can not only meet the requirements of all kinds of portable computers, but also realize the remote access of computer LAN, fax, e-mail and other functions.
Cordless telephone system: the extension of the wired fixed telephone terminal, and the prominent feature of the cordless telephone system is its flexibility and convenience. This kind of fixed wireless terminal can simultaneously with several wireless sub machine, sub machine and machine tools in addition to the call, the communication between the sub machine can also be. One kind of working frequency is usually 45MHz, and the antenna is covered about 100 meters. Another type of cordless telephone system, such as DECT and PHS, operates at frequencies from 800MHz to 1.9GHz.
Wireless local loop system: wired fixed line subscriber wireless access to public telephone network is called wireless local loop system. This method is more economical and practical. It not only reduces maintenance cost, shortens construction period, but also facilitates equipment expansion. It is especially suitable for outlying areas far away from the city. The GSM standard, CDMA, FDMA, and TDMA technologies are also used in wireless local loops. Wireless local loop is mainly aimed at fixed wireless subscriber access, so its frequency is not the same as that of public mobile communication network, mainly distributed in the frequency band from 1.8GHz to 2.5GHz. One point to multipoint microwave communication equipment, is actually a typical wireless local loop device, it generally uses TDMA TDMA, central station by users and public telephone network connected by omnidirectional antenna and distribution station communication around the periphery, to provide fixed telephone service.
