接入3G的無線局域網(wǎng)及傳輸性能研究.pdf

1、華中科技大學(xué)碩士學(xué)位論文接入3G的無線局域網(wǎng)及傳輸性能研究姓名：曹文波申請學(xué)位級別：碩士專業(yè)：計(jì)算機(jī)系統(tǒng)結(jié)構(gòu)指導(dǎo)教師：文遠(yuǎn)保20060510IIAbstractNowadaysthe3rdGenerationMobileCommunicationSystem(3G)isdevelopingfast.AtthesametimeWLAN（WirelessLocalAreawk）ispoisedtobecomeanimptantapplica

2、tion.3Gcanprovidewidecoveredservicesbutithasalowdatarate.WLANhasahighdataratebutitcoversasmallarea.TherefeHighspeedlowpricewirelessdataservicescanbeprovidedbyseamlesslinkbetween3GWLAN.WLANispromisingtobeintegratedwith3G.

3、HowtointegratedWLANwith3GhowtotransmitvoicevideooverWLANintegratedwith3Gwillbeproblemsthatneedtobesolvedquickly.Sixschemesfintegrating3GwithWLANhasbeendiscussedwhicharefromsimplelinktoseamlessoperationbetweenthetwosystem

4、s.AccdingtotheextendofdependingoneachothertherearetwomodesofintegratingWLAN3G:theloosecouplingmodethetightcouplingmode.InthetightcouplingmodeWLANactsasaRadioAccesswkwhichisconnectedwith3Gsharesthecommonresources.Intheloo

5、secouplingmodeWLANonlysharesAAA（Authentication、AuthizationAccounting）serverisnotconnectedwith3G.AftertheintegrationVoWLAN（VoiceoverWirelessLocalAreawk）willbeanimptapplicationsupptingseamlessvoiceservices.Itsperfmancearem

6、ainlyvoiceQoS（QualityofService）voicecapacity.AstothecapacityproblemtheproposedMultiplexMulticastschemecanimprovethecapacitybycloseto100%withoutchangingthestard802.11protocolwhichcanbedeployedovertheloosecouplingmodeabove

7、.IntheschemepacketsfromseveralVoIP（VoiceoverInterProtocol）streamshasbeenmultiplexedintoonemulticastpacketftransmissionovertheparedtothevoicetransmissionoverWLANhighqualityvideotransmissionismedifficulttobeachieved.Wirele

8、ssvideocodingWLANvideotransmissionhasbecomethefocuses.AmongtheWirelessvideocodingsFGS(Finegranularityscalability)isafirenewscalablevideocodingmethod.Severalcrosslayertechniqueshasbeenstudiedinwhichthetransmissionmechanis