前沿课题讲座05_手机电视

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1、手机电视孙松林北京邮电大学Email:slsun@bupt.edu.cnMobile:13511017172ContentDVB-HDigitalVideoBroadcastingforHandheldUMTS-PSSUniversalMobileTelecommunicationsSystemPacketSwitchedStreamIntroductionConvergenceofdigitalmediaandcommunicationgiveuserspossibilitytoconsumemostdigitalcontentalsoinmobileenvironmentTheemergi

2、ngDVB-HstandardaimstoprovidedigitalTVreceptioninmobiledevicesEarlierknownasDVB-XDVB-HisbeingstandardizedbyandadhocgroupoftheDVBorganizationExpectedtobestandardizedinthefirstquarterof2004DVB-Hcombinestraditionaltelevisionbroadcaststandardswithelementsspecifictohandhelddevices;mobility,smallerscreensa

3、ndantennas,indoorcoverageandrelianceonbatterypowerMotivationforcreatingDVB-HWhynotuseUMTS?NotscalableformasscontentdeliveryFordeliveryofmassmediacontent,broadcastnetworksshouldbepreferredoverpoint-to-pointcellularnetworksWhynotuseDVB-T?WasdesignedforrooftopreceptionNeedforanefficientpowersavingmecha

4、nismInadequateimpulsenoiseprotectionWhynotuseDAB?DesignedfordeviceswithsimilarpowerconstraintsbuttoonarrowspectrumisassignedfordatatransmissionDAB=DigitalAudioBroadcasting四种不同的典型导频分布图(a)(b)(c)(d)DVB-T系统中的导频插入方案DVB-T的帧结构DVB-TTerrestrialDigitalTelevisionStandardUsedin36countriesworldwideOne-to-manybro

5、adbandwirelessdatatransportVideo,audio,dataand–importantly–IPpacketsScalable:cellsizeupto100km(DVB-Hcellsizeissmaller)Hugecapacity:54channelseach5-32Mbit/sShutdownofanalogTVwillfreeuphugefrequencycapacityforDVB-TusageDVB-T=DigitalVideoBroadcasting-TerrestrialDVB-T(cont.)DevelopedforMPEG-2streamdistr

6、ibution,butcanbasicallycarryanydataFlexible,hasmanymodes,4.98-31.67Mbit/s@C/N=25dBCOFDMmulticarriermodulationwith2kand8kmodesOneDVBchannelis~8MHz1705subcarriers(spacing:4464Hz)-2kmode6817subcarriers(spacing:1116Hz)-8kmodeCarriermodulation:QPSK,16QAMor64QAMErrorcorrection:convolutionalcodeandSalomon-

7、ReedBasicmodeinFinland:64QAM,coderate=2/3,guardinterval1/8Gives22.12Mbits/scapacitywhenC/N=19.2dBand8MHzchannelCOFDM=CodedOrthogonalFrequencyDivisionMultiplexingC/N=CarriertoNoiseratioMobilereception