基于IP的語音傳輸通話質(zhì)量改進(jìn)研究與實(shí)現(xiàn).pdf

1、湖南大學(xué)碩士學(xué)位論文基于IP的語音傳輸通話質(zhì)量改進(jìn)研究與實(shí)現(xiàn)姓名：祝宇成申請學(xué)位級別：碩士專業(yè)：軟件工程指導(dǎo)教師：周應(yīng)權(quán)楊志新20071020AbstractVoiceoverIP(VolP)isanewandhighlychallengingtechnologywhichhasbeenemergedforalmosttenyearsTraditionalPSTNemergeditslimitationwhenthetechnology

2、isdevelopingAtthesametime，PacketSwitchedDataNetworkshasgrownsignificantlyinQualityofService(QoS)VoWwillbethekeytechnologyofthenextgenerationtelecom，andreplacethetraditionaltelecomtechonologygraduallyVolPcanprovidetheserv

3、icesintegratedwithdataandvoice，andwillmakesignificantprogressinthefutureThoughVoWhaslotsofadvantagesthanthetraditionaltelecomtechnologyitneedstobeimprovedbeforebeingmorewidelyacceptedinpracticeQualityofvoiceisanimportant

4、factorwhichhasagreatinfluenceonfurtherprogressNetworklayercouldn’tprovideanyguaranteesofQoSforVoWapplicationduetoIPnetworkproviding“besteffort”serviceonlyButtherealtimeapplicationssuchasVoWrequireaveryhighqualityservices

5、ResearchonQoScontroltechnologyofapplicationlayerhasdrawnmuchattentionrecentlyThisthesissetBolotalgorithmasthetargetalgorithm，andsetitasthecoretoanalysetheprocessofitsimplementandcorrelativetechnologyandproblemsFinallythi

6、sthesisbringoutanimprovedarithmeticFirstthisthesisintroducesthecorrelativebackgroundknowledgeofVjIP，andanalysesthefactorswhichaffectthequalityofVolPsuchasdelaydithering，andpacketlostAtthesametime，thisthesisresearchthesta

7、tusquoofthedomesticvoicequalitydevelopment，analysetheFEC，encodinganddecoding，echoavoidtechnologywhichisusedinthenewdevelopmentSecond，thisthesisintroducetheQoStechnologywhichisusedinthepracticeapplications，analysetheadvan

8、tageanddisadvantage，andtheprojectsintheapplicationSuchas：queuemechanism，slice，fluxadjusting，headercompressing，anddifferenceserviceThispartcomparetheFECandLBRwhichusedintherecoverymechanismAttheend，thispartanalysesomecorr

9、elativetechnologyofVolPThisthesismakeanin—depthanatomyoftheimplecationofBolotThispartmakeaemphasesanalysisontheBolot’Srecoverymechanism，suchas：losingprocess，errorcontrolmechanism，andofferanimproveredschemeforitThisscheme