移動通信技術(shù)發(fā)展趨勢-預(yù)覽頁
【正文】 he recent research, two year Europe39。s demand, global open agreement wireless application protocol (WAP) arises at the historic moment. WAP was transmits the Internet information content as well as the valueadded service to the mobile termination has provided one kind of open general standard, has realized IP and the GSM network bridge joint, was one provides accelerates the market for the manufacturer to grow, to avoid the network cleft grafting, protecting the standard which the operator invested, WAP guaranteed that any handset could work with WAP the patible GSM. （2）data rate development The GSM bearer service provides the GSM data rate is highest can only achieve (HSCSD) technology will realize the 57kbit/s data rate, to requested the continual bit rate and the transmission latency small application is ideal, like videoconference, , longdistance turning on enterprise39。s next stage is and even moves the multimedia shifts personally to the wireless data, this progress already started, and will bee in the future the important point of growth. Will move personally multimedia will supply is unable to imagine, consummation individual service and the wireless information according to the place for the people, will work to the people with life each aspect has the influence. In individual multimedia world, the voice mail and the are transmitted to move in the multimedia mailboxes。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 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 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 demand
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