2023学年完整公开课版BroadbandCopperAccessNetworkUsingADSL2

《Communicationintroduction》coursePresenter：YingyingLiTeachingResourceDatabaseofCommunicationTechnologySHENZHENPOLYTECHNICBroadbandCopperAccessNetworkUsingADSL2+/VDSL2

TechnologyTeachers:YingyingLi,SunanWangBroadbandCopperAccessNetworkUsingADSL2+/VDSL2ThebandwidthperformancedeliveredatthehomeofasubscriberbyacopperbasedaccessnetworkusingADSL2+/VDSL2technologydependsonthelengthof

thecopperloop.Typically,itispossibletoachieve24–30Mbpsovera1–1.5km

copperloopplant.Thisnetworkarchitectureiscommonlyusedbynumerousnetworkoperatorsaroundtheworld.Thisoptionisattractivefortheoperatorsbecause

theycanre-usetheexistinglastsectionofthecopperloopplantalreadyinstalled.

Doingso,theoperatorsareleveraginganimportantassettheyalreadyown.

Theyneedtopushthefiber-optictechnologydeeperintheaccessnetworktoconnectaremoteADSL2+/VDSL2digitalsubscriberlineaccessmultiplexer(DSLAM),but

thisinvestmentislessimportantthaniftheywoulddecidetogowiththefiberoptic

allthewaytothehome.

BroadbandCopperAccessNetworkUsingADSL2+/VDSL2Itisinterestingtocomparethetypical24–30Mbpsbandwidthperformance

(downstream)and1Mbps(upstream)overareasonabledistanceof1–1.5kmcopperloopplantusingADSL2+/VDSL2technologywiththerealisticaccessnetworkbandwidthrequirementforbroadbandIPconnectionsscenariopresentedin

Fig.1.1.Inthispreviousscenario,threesimultaneousMPEG-4AVC-encodedIP

videostreams(IPTVorVoD)aredownloaded,correspondingtoabandwidthrequirementof23Mbps,twoviewedstreams,fullydecoded,9Mbpseachstreams,

andonestreamdigitallyrecordedonapersonalvideorecorder(PVR)at5Mbps.

BroadbandCopperAccessNetworkUsingADSL2+/VDSL2Thenetworkwillrequireanextra2–3Mbpsofbandwidthforbuffering,leavingvery

littlebandwidthextraforInterneton-linegamingandpeer-to-peerfilesharingonthe

totalcapacityof25–30Mbps.Ifthisscenarioseemsrealistictothereader,hemust

cometotheconclusionthatanaccessnetworkarchitectureusingADSL2+/VDSL2

technologyhasverylittlemarginforerrorwhenmulti-streamshighdefinitionIP

videoishighlyconsideredbythesubscribers.

BroadbandCopperAccessNetworkUsingADSL2+/VDSL2BroadbandcopperaccessnetworkusingADSL2+/VDSL2technologyremainsa

technologyofchoicetodeliversimultaneouslyonehigh-definitionIPvideostream

withoneortwostandarddefinitionIPvideostreams,highspeedInternetservices

andVoIPcalls(Fig.1.2)

BroadbandCopperAccessNetworkUsingADSL2+/VDSL2VDSL2technologyhasbeenusedalotforinsidethebuildingcopper-basednetworkinMulti-dwellingunits(MDU).InMDUsituations,wherecopperloopplant

distancesaretypicallysmallerthan500–600m,VDSL2technologycandeliverover

60Mbpsofbandwidth(40Mbpsdownstreamand20Mbpsupstream).VDSL2technologydeploymentinsideMDUhasbeenadoptedasamainstreamtrendforeconomicandeaseofinstallationreasons.

BroadbandCopperAccessNetworkUsingADSL2+/VDSL2BroadbandCopperAccessNetworkUsingADSL2+/VDSL2Thecapitalexpenditure(CAPEX)ofbuildingabroadbandcopperaccessnetworkusingADSL2+/VDSL2technologyisdefinitelylowerthanafiber-to-thehomeproject.Thesavingassociatedwiththere-useofthelastcopperloopplantissignificant,whenadistanceof1–1.5kmiskept.Thetrade-offsfortheoperatorarenottrivial,thebandwidthperformancewillbelimitedandtheoperationexpenditure(OPEX)tomaintainthecopperloopplantwillbegreater,comparedtobandwidthperforma