The use and speed of broadband wireless access are different

For broadband wireless access network, the world has three kinds of standards, that is, IEEE Standards, ATM Forum standards and European ETSI standards. European ETSI Broadband Wireless access Network Group research, study the use of wireless access networks, concluded that the use of different needs of the data transmission rate is different. For example, TV on demand requires 1. 5mbit/s to 6mbit/s, online browsing needs 2mbit/s, access to the enterprise network needs 10mbit/s,lan interconnection needs 25mbit/s. Therefore, the broadband access network equipment, there are currently five categories.
The first category is to provide 2mbit/s rate equipment, such as Ericsson's airline system, microwave-point multiple access system can also provide a 2mbit/s rate.
The second category is the use of local multicast system LMDS. LMDs was first developed by the US Cellularvisim company, and now Ericsson, Nortel Networks, Alcatel France, Bosch, USA Lucent, Hewlett-Packard, Hughes and many other companies offer LMDS. The LMDS system consists of base station, client device, user device and network management system. The base station and the client are composed of an outdoor unit (a microwave transceiver and an antenna) and an indoor unit (modem), which is connected by an air interface. LMDS is operated in a bit multiple access mode, similar to a microwave, but unlike a traditional microwave, lmds can form a cellular network operation.
The LMDS working band has 24GHz, 28GHz, 31GHz, 38GHz and 40GHz. In the United States, LMDs uses a band of 27. 5ghz~28. 35GHz and 29. 1ghz~29. 5GHz; In Europe, LMDS is experimenting with 40. 5ghz~42. 5GHz. LMDS does not support mobile services, can support fixed voice, data, image services and ATM, TCP/IP, MPEG2 and other standards, its access rate can reach nx64kbit/s to 2mbit/s, or even up to 155mbit/s, working band bandwidth at least 1000MHz. LMDS is a new technology, should arouse the attention of industry people. Attention should be paid to the application of LMDS in the Internet and high-speed data communication.
The third category is wireless LAN and wireless ATM. Wireless LAN WLAN and wireless ATM have two standard, namely IEEE802. 11 and Wireless ATM Forum standards. The concept of wireless ATM (WIRELESSATM) was introduced in ITU (ITU) in 1993. June 1996, ATM Forum (ATMFORUM) formally set up a wireless ATM Working group, responsible for wireless ATM standardization work and system planning. The research work of Wireless mobile ATM (WMATM), which is affiliated to wireless ATM, has been carried out in Europe and America, Germany, Sweden, Italy and other European countries have invested heavily, and the German National Information Research Center has proposed a scheme to overlay TCP/IP on the wireless ATM layer, To provide wired/wireless broadband Internet services, and has achieved research results. The United States has also proposed a wireless ATM experiment program. Wireless ATM is a newly-started broadband wireless technology, its basic technology is wireless access and mobile ATM. Wireless ATM is currently used to form wireless access network has not yet seen products, but the trend is gratifying.
The fourth category is the standard established by the European Telecommunication Standards Association (ETSI). 1992 ETSI proposed the first HIPERALN standard, currently, ETSI according to the Acts plan announced the new standard, the new standard provides access rate over 25mbit/s, including multiple broadband wireless access items, access rate varies with the working frequency, The rate available at 60GHz is up to 155mbit/s.
The fifth category is the use of optical wireless communication technology. Optical wireless communication is a new concept, in our mind originally only optical cable communication (optical communication), optical communication is the infrared signal transmission in the fiber. Infrared light signals in the wired (optical fiber) can be spread, then in the wireless (atmosphere) can also be spread in the atmosphere to become optical wireless communication (opticalwirelesscommunication), optical fiber communication in the infrared light (light-emitting tube and laser tube) can also use optical wireless communication. Optical wireless communication receiver used in photoelectric detection tube can be pin or APD (avalanche tube), optical wireless system can be used for point-to-point communication, but also to form a optical wireless local area network (Owlan). A number of experiments have been carried out on optical wireless system abroad, in which there are 40 meters transmission distance and the data transmission rate is 1gbit/s. After the optical wireless system is put into practice, the broadband wireless access will add a new one.