移動通信技術(shù)發(fā)展趨勢-閱讀頁
2025-07-10 03:25本頁面
【正文】 e massive visible mobile phone, will also realize moves the Internet and World Wide Web glances over. Wireless videoconference such application will find at everywhere likely, electronic merce will develop vigorously. Also has each kind of mailbox and the entertainment anytime and anywhere regarding the movement in user serves. Networking wide band In the telemunications industry history, the mobile munication possibly is the technology and the market development quickest domain. The service, the technology, the market three between are one kind of interactive relations, follows the user to the data, multimedia service demand increase, the network service to the digitization, the grouping development, the motion network is moving toward the wide band inevitably. Through the use telephone exchange technology and the honeyb radio technology, were born in the late 70s the first generation of simulation mobile phone. AMPS (North America honeyb system), NMT (Northern Europe mobile phone) and TACS (omnidirectional munications system) is three kind of main narrow band mock standard. A first generation of wireless networking39。s line. The user first time can any place wireless receive which is in them and dials telephones. The second generation of system has introduced the digital radio technology, it provides the higher network capacity, improved the voice quality and the secrecy, and has introduced the seamless international roaming for the user. Today world market second generation of digital wireless standard, including GSM, MMPS, PDC (Japan digital cellular system) and IS95 CDMA and so on, still for narrow band system. The third generation moves the system, namely IMT2000, is one kind of genuine wide band multimedia systems, it can provide the high grade wide band synthesis service and realize the global seamless cover. after 2000, the narrow band mobile phone service demand still will be very big, but along with Internet and so on high speed data correspondence and the multimedia correspondence demand39。s intellectualized development, the motion intelligent network lives from this. About the motion intelligent network39。s evolution, the network intellectualized degree unceasingly is also promoting. The intelligent network and the intelligent service constitutes in the future the persontoperson munication basic condition. Higher bandFrom the first generation of simulation mobile phone, to the second generation of numeric move network, to future third generation mobile munication system, the network use39。s use frequency band is also 900 MHz. In the second generation of network, the GSM system39。s capacity, in 1997 presented the 1800MHz system, the GSM 900/1800 dualfrequency network popularized rapidly. in 2002 will invest mercial third generation system IMT2000 to locate in the 2GHz frequency band. The network tends the fusion, moves toward the unification The technical development, market demand39。s aggravating as well as the market control policy
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