理论研究通用组无线业务-外文翻译.docxVIP

Theoretical Study of the General Packet Radio ServiceAbstract: As communications technology continues to mature a -nd users’ quality have become increasinglydemanding, new da -ta applications are emerging and are reaching the generalpublic. Through the use of GPRS(General Packet Radio Service) techn -ology, the existing GSM networks can be easily achieved with simplehigh-speed data packet access, enabling mobile operators to respond rapidly to market demands and gaincompetitive adva -ntage. This paper aims to provide acomprehensive yet simple overview of the GPRS systemfrom the user’s and from the arch -itectural perspectives.Keywords:GPRSnetworks;Voice/dataintegration; Multiple-channels; Packet radio; Telecommunications1 IntroductionIn the late 1800s, Marconi did the pioneer workestablishing the first successful radio link between aland-based station and a tugboat. Since then,wireless communication systems have beendeveloping and evolving with a furious pace. Thenumber ofmobile subscribers has been growingtremendously in the past decades. In the early stages,wireless communication systems were dominated bymilitary usage and supported according to militaryneeds and requirements. During the last half acentury, with increasing civil applications of mobileservices,commercial wireless communicationsystems have been taking the lead.The early wireless systems consisted of a basestation with ahigh-power transmitter and served alarge geographic area. Each base station could serveonly a small number of users and was costly as well.The systems were isolated from each other and onlya few of the communicated with the PSTNs (PublicSwitched Telephone Networks). Today, the cellularsystems consist of a cluster of ba -se station with lowpowerradio transmitters. Each base station s -erves asmall cell within a large geographic area. The totalnum -ber of users served is increased because ofchannel reuse and al -so larger frequency bandwidth.Global system for mobile communications is th