《通信英语》课件-通信英语（9-17）

通信英语UNIT9

GSM(GlobalSystemforMobileCommunication)Thesuccessofmobilesystemsacrosstheworldisasignthatcommunicationismovingtowardsamorepersonalized,convenientsystem.success成功，成就sign标记，符号personalize个性化convenient便利的，方便的Peoplewhohavetouseamobilephoneonbusinesssoonbegintorealizethattheabilitytophoneanytime,anyplaceinone’spersonalliferapidlybecomesanecessity,notaconvenience.business业务，生意realize实现，认识到ability能，能力necessity必要性，需要Thespeedandrapiditywithwhichthepersonalcommunicationsrevolutiontakesplaceis,unlikefixedtransmissionsystems,highlydependentontechnologyandcommunicationstandards.rapidity快，迅速revolution革命，彻底改变fixed固定的standard标准Formobilethethreekeyelementstoachievingservicetake-uparethecost,thesizeandtheweightofthephone,andthecostandqualityofthelink.elementachievetake-upcostqualitylinkIfanyofthesearewrong,especiallythefirsttwo,thenmarketgrowthisliabletobeseverelyrestricted.especiallymarketgrowthliableseverelyrestrictThefixedtelephoneserviceisglobalandtheinterconnectionvariesfromcoaxialcabletoopticalfibreandsatellite.global全球的interconnection互联vary变化，改变coaxial同轴的，共轴的cable电缆，有线

satellite卫星Thenationalstandardsaredifferent,butwithcommoninterfacesandinterfaceconversion,interconnectioncantakeplace.standard标准common公共的，共同的interface接口conversion转化，变换Formobiletheproblemisfarmorecomplex,withtheneedtoroamcreatinganeedforcomplexnetworksandsystems.problem问题complex复杂的roam漫游create产生Thusinmobilethequestionofstandardsisfarmorecrucialtosuccessthanfixedsystems.Inaddition,thereisalsothevexedquestionofspectrumallocationinthemobilearea.crucial决定性的，紧要关头的vexed争论不休的，棘手的spectrum频谱allocation配给，分配Mobilesystemsoriginallyoperatedinanalogmodeinthe450MHzband,movinglaterto900MHzwithdigitalGSMandthento1,800MHzwithpersonalcommunicationsystems.Thehistoryofmobilitycansplitintogenerations.analog模拟的mode方式，样式mobility流动性，移动性split裂开，破裂generation一代Thefirstgenerationsystemsweretheadvancedmobilephonesystems(AMPS)intheUS,totalaccesscommunicationsystem(TACS)inmostofEuropeandNordicmobiletelephonesystem(NMT);whichwereallanaloguesystems.advancedtotalaccessNordicThesecondgenerationisvarymuchdominatedbythestandardfirstsetoutinEuropebythegroupspecialmobile(GSM)committee,whichwasdesignedasaglobalmobilecommunicationsystem.dominatespecialcommitteeTheGSMsystemisbasedonacellularcommunicationsprinciplewhichwasfirstproposedasaconceptinthe1940sbyBellSystemengineersintheUS.base以为基础cellular蜂窝状的principle原则，原理propose提议，建议concept概念Theideacameoutoftheneedtoincreasenetworkcapacityandgotroundthefactthatbroadcastmobilenetworks,operatingindenselypopulatedareas,couldbejammedbyaverysmallnumberofsimultaneouscalls.IdeacapacitybroadcastdenselypopulatejamsimultaneousThepowerofthecellularsystemwasthatitallowedfrequencyreuse.powercellularThecellularconceptisdefinedbytwofeatures,frequencyreuseandcellsplitting..featurereusecellsplittingFrequencyreusecomesintoplaybyusingradiochannelsonthesamefrequencyincoverageareasthatarefarenoughapartnottocauseco-channelinterference.comeintoplaychannelcoverageapartcauseco-channelinterferenceThisallowshandlingofsimultaneouscallsthatexceedthetheoreticalspectralcapacity.HandlingsimultaneousexceedtheoreticalspectralcapacityCellsplittingisnecessarywhenthetrafficdemandonacellhasreachedthemaximumandthecellisthendividedintoamicro-cellularsystem.cellsplittingtrafficdemandmaximumdividemicro-cellularTheshapeofcellinacellularsystemisalwaysdepictedasahexagonandtheclustersizecanbeseven,nineortwelve.shapecellulardepicthexagonclusterUNIT10

4G1Intelecommunications,4G

isthefourthgenerationofmobilecommunication

technologystandards.A4Gsystemprovidesmobileultra-broadband

Internetaccess,forexampletolaptopswithUSB

wirelessmodems,tosmartphones,andtoothermobiledevices.Conceivableapplicationsincludeamendedmobilewebaccess,IPtelephony,gamingservices,high-definition

mobileTV,videoconferencing,3Dtelevision,andcloudcomputing.laptopn.笔记本电脑modemn.调制解调器smartphonen.智能手机conceivablea.想得到的，可想象的amendv.修改，改善，改进Two4Gcandidatesystemsarecommerciallydeployed:theMobileWiMAXstandard(firstusedinSouthKoreain2006),andthefirst-releaseLongTermEvolution(LTE)standard(inOslo,NorwayandStockholm,Swedensince2009).Ithashoweverbeendebatedifthesefirst-releaseversionsshouldbeconsideredtobe4Gornot2.InMarch2008,theInternationalTelecommunicationsUnion-Radiocommunicationssector(ITU-R)specifiedasetofrequirementsfor4Gstandards,namedtheInternationalMobileTelecommunicationsAdvanced(IMT-Advanced)specification,settingpeakspeedrequirementsfor4Gserviceat100

Mb/sforhighmobilitycommunication(suchasfromtrainsandcars)and1

Gb/sforlowmobilitycommunication(suchaspedestriansandstationaryusers)3.definitionn.定义，清晰度conferencen.会议，讨论，协商candidaten.候选人，候选者commerciallyad.商业上，通商上deployv.部署，展开Asopposedtoearliergenerations,a4Gsystemdoesnotsupporttraditionalcircuit-switchedtelephonyservice,butall-InternetProtocol(IP)basedcommunicationsuchasIPtelephony.Thespreadspectrumradiotechnologyusedin3Gsystemsisabandonedinall4GcandidatesystemsandreplacedbyOFDMA，multi-carriertransmissionandotherfrequency-domainequalization(FDE)schemes,makingitpossibletotransferveryhighbitratesdespiteextensivemulti-pathradiopropagation(echoes)4.Thepeakbitrateisfurtherimprovedbysmartantennaarraysformultiple-inputmultiple-output(MIMO)communications.releasev.释放，发射，发布debatev.辩论，争论，讨论specifyv.指定，详细说明LTEAdvanced(LongTermEvolutionAdvanced)isacandidateforIMT-Advancedstandard,formallysubmittedbythe3GPPorganizationtoITU-Tinthefall2009,andexpectedtobereleasedin2013.Thetargetof3GPPLTEAdvancedistoreachandsurpasstheITUrequirements.LTEAdvancedisessentiallyanenhancementtoLTE.Itisnotanewtechnology,butratheranimprovementontheexistingLTEnetwork.ThisupgradepathmakesitmorecosteffectiveforvendorstoofferLTEandthenupgradetoLTEAdvancedwhichissimilartotheupgradefromWCDMAtoHSPA5.LTEandLTEAdvancedwillalsomakeuseofadditionalspectrumsandmultiplexingtoallowittoachievehigherdataspeeds.CandidateSubmitSurpassExistingUpgradeSpectrumJustwhenLTEandWiMaxarevigorouslypromotingintheglobaltelecommunicationsindustry,theformer(LTE)isalsothemostpowerful4Gmobilecommunicationsleadingtechnology,andquicklyoccupiedtheChinesemarket.TD-LTE,oneofthetwovariantsoftheLTEairinterfacetechnologies,isnotyetmature,butmanydomesticandinternationalwirelesscarriersoneafteranotherturntoTD-LTE6.IBM'sdatashowthat67%oftheoperatorsareconsideringLTE,becausethisisthemainsourceoftheirfuturemarket7.Whileonly8%oftheoperatorsareconsideringtheuseofWiMAX.vigorouslyOccupyVariantCarrierOperatorTD-LTEisnotthefirst4Gwirelessmobilebroadbandnetworkdatastandard,butitisChina's4GstandardthatwasamendedandpublishedbyChina'slargesttelecomoperator-ChinaMobile8.Afteraseriesoffieldtrials,itisexpectedtobereleasedintothecommercialphaseinthenexttwoyears.AmendPublishTrialReleaseThemainreason4Gisfasterthan3GisbecauseofOrthogonalFrequency-DivisionMultiplexing(OFDM).Itsoundscomplicated,butit'sthesametechnologyusedinWi-Fi,ADSLbroadbandanddigitalTV9.OFDMisatechniqueforsqueezingmoredataontothesameamountofradiofrequency10.Italsoreduceslatencyandinterference.Dataissplitupandsentviasmallchunksoffrequencyinparallel,thereforeincreasingthecapacityofthenetwork11.squeezev.挤压，挤interferencen.干扰，干涉latencyn.潜伏，潜在因素chunkn.大块，数据块configurationn.配置，结构Multiple-inputandmultiple-output,orMIMO,isanotherreason4Gisabletoprovidefasterspeeds.Itissimplytheuseofmultipleantennaarraysatboththetransmitterandreceivertoimprovecommunicationperformance12.Theperformanceofradiocommunicationsdependsonanantennasystem,termedsmartorintelligentantenna.Intheearly1990s,tocaterforthegrowingdatarateneedsofdatacommunication,manytransmissionschemeswereproposed.AntennaArrayPerformanceSmartIntelligentSchemeOnetechnology,spatialmultiplexing,gainedimportanceforitsbandwidthconservationandpowerefficiency13.Spatialmultiplexinginvolvesdeployingmultipleantennasatthetransmitterandatthereceiver.Thisallowsmoredatatobetransferredwithoutrequiringadditionalbandwidthordrawingmorepower14.Themostcommonconfigurationcurrentlyisa2x2MIMO,foundinmanysmartphonesandsometablets.tabletn.写字板，平板电脑Asdatarateshaveincreasedovertheyears,higherperformanceapplicationshavebeenenabledonthemobilehandset.Contextawarenesswillallowphonestosenseandreacttoauser’ssurroundings.Forexample,imagineawomanisoutshoppinginalocalmall.ShepassesbyaposterofherfavoriteTVstar.Herphoneandthepostersenseeachotherandshereceivesinformationdirectlyonherphoneaboutshowtimesorevenanoffertodownloadthestar’slatesthitsingle.ContextSurroundingPosterFavoriteUNIT11CircuitSwitchingandPacketSwitching1Therearetwobasictypesofswitchingtechniques:circuitswitchingandmessageswitching.Incircuitswitching,atotalpathofconnectedlinesissetupfromtheorigintothedestinationatthetimethecallismade,andthepathremainsallocatedtothesource-destinationpair(whetherusedornot)untilitisreleasedbythecommunicatingparties2.Theswitches,calledcircuitswitches(orofficeexchangeintelephonejargon),havenocapabilityofstoringormanipulatinguser'sdataontheirwaytothedestination3.destinationn.目的地，终点allocatevt.

分配，分派，配给release

vt.

释放，放松，发布jargon

n.

行话，土语manipulate

vt.

处理，操纵Thecircuitissetupbyaspecialsignalingmessagethatfindsitswaythroughthenetwork,seizingchannelsinthepathasitproceeds4.Oncethepathisestablished,areturnsignalinformsthesourcetobegintransmission.Directtransmissionofdatafromsourcetodestinationcanthentakeplacewithoutanyinterventiononthepartofthesubnet.seize

vt.

抓住，占领，俘获proceed

vi.

进行，继续inform

vt.

通知，告诉intervention

n.

干预，干涉，妨碍subnet

n.

子网，分网

Inmessageswitching,thetransmissionunitisawell-definedblockofdatacalledamessage.Inadditiontothetexttobetransmitted5,amessagecomprisesaheaderandachecksum.Theheadercontainsinformationregardingthesourceanddestinationaddressesaswellasothercontrolinformation6;thechecksumisusedforerrorcontrolpurposes.Theswitchingelementisacomputerreferredtoasamessageprocessor7,withprocessingandstoragecapabilities.Messagestravelindependentlyandasynchronously,findingtheirownwayfromsourcetodestination8.Firstthemessageistransmittedfromthehosttothemessageprocessortowhichitisattached9.subnet

n.

子网，分网block

n.

一批，一组，一块header

n.

头，头部checksum

n.

检验和，检验项regard

v.

与……有关，涉及Oncethemessageisentirelyreceived,themessageprocessorexaminesitsheader,andaccordinglydecidesonthenextoutgoingchannelonwhichtotransmitit10.Ifthisselectedchannelisbusy,themessagewaitsinaqueueuntilthechannelbecomesfree,atwhichtimetransmissionbegins.Atthenextmessageprocessor,themessageisagainreceived,stored,examined,andtransmittedonsomeoutgoingchannel,andthesameprocesscontinuesuntilthemessageisdeliveredtoitsdestination.Thistransmissiontechniqueisalsoreferredtoasthestore-and-forwardtransmissiontechnique11.header

n.

头，头部checksum

n.

检验和，检验项regard

v.

与……有关，涉及attach

vt.

缚，系，捆entirely

ad.

完全地，彻底地accordingly

ad.

相应地queue

n.

行列，长队variation

n.

变动，变化，变更Avariationofmessageswitchingispacketswitching.Herethemessageisbrokenupintoseveralpiecesofagivenmaximumlength,calledpackets.Aswithmessageswitching12,eachpacketcontainsaheaderandachecksum.Packetsaretransmittedindependentlyinastore-and-forwardmanner.Withcircuitswitching,thereisalwaysaninitialconnectioncostincurredinsettingupthecircuit13.Itiscost-effectiveonlyinthosesituationswhereoncethecircuitissetupthereisaguaranteedsteadyflowofinformationtransfertoamortizetheinitialcost14.Thisiscertainlythecasewithvoicecommunicationinthetraditionalway,andindeedcircuitswitchingisthetechniqueusedinthetelephonesystem.Communicationamongcomputers,however,ischaracterizedasbursty.Burstinessisaresultofthehighdegreeofrandomnessencounteredinthemessage-generationprocessandthemessagesize,andofthelowdelayconstraintrequiredbytheuser15.incur

vt.

招致，惹起guarantee

vt.

保证，担保steady

a.

平稳的，不变的amortize

vt.

缓冲，分摊Theusersanddevicesrequirethecommunicationresourcesrelativelyinfrequently;butwhentheydo,theyrequirearelativelyrapidresponse.Ifafixeddedicatedend-to-endcircuitweretobesetupconnectingtheendusers16,thenonemustassignenoughtransmissionbandwidthtothecircuitinordertomeetthedelayconstraintwiththeconsequencethattheresultingchannelutilizationislow17.

Ifthecircuitofhighbandwidthweresetupandreleasedateachmessagetransmissionrequest,thentheset-uptimewouldbelargecomparedtothetransmissiontimeofthemessage,resultingagaininlowchannelutilization18.DedicatedAssignDelayConstraintConsequenceUtilizationTherefore,forburstyusers(whichcanalsobecharacterizedbyhighpeak-to-averagedataaterequirements),store-and-forwardtransmissiontechniquesofferamorecost-effectivesolution,sinceamessageoccupiesaparticularcommunicationslinkonlyforthedurationofitstransmissiononthatlink;therestofthetimeitisstoredatsomeintermediatemessageswitchandthelinkisavailableforothertransmissions.Thusthemainadvantageofstore-and-forwardtransmissionovercircuitswitchingisthatthecommunicationbandwidthisdynamicallyallocated,andtheallocationisdoneonthefinebasisofaparticularlinkinthenetworkandaparticularmessage(foraparticularsource-destinationpair).bursty

n.

突发性，突发randomness

n.

随机，机遇constraint

n.

强迫，强制，制约relatively

ad.

相对地，比较地response

n.

回答，响应dedicated

a.

专用的assign

vt.

分配，指派，委派utilization

n.

利用dynamically

ad.

动态地，有生气地Packetswitchingachievesthebenefitsdiscussedsofarandoffersaddedfeatures.Itprovidesthefulladvantageofthedynamicallocationofthebandwidth,evenwhenmessagesarelong.Indeed,withpacketswitching,manypacketsofthesamemessagemaybeintransmissionsimultaneouslyoverconsecutivelinksofapathfromsourcetodestination,thusachievinga"pipelining"effectandreducingconsiderablytheoveralltransmissiondelayofthemessageascomparedtomessageswitching.benefit

n.

利益，好处，恩惠simultaneously

ad.

同时地，同时发生consecutive

ad.

连续地，连贯地pipeline

v.

用管道输送procedure

n.

过程，步骤entity

n.

存在，实体Ittendstorequiresmallerstorageallocationattheintermediateswitches.Italsohasbettererrorcharacteristicsandleadstomoreefficienterrorrecoveryprocedures,asitdealswithsmallerentities.Needlesstosay19,packetswitchingpresentsdesignproblemsofitsown,suchastheneedtoreorderpacketsofagivenmessagethatmayarriveatthedestinationnodeoutofsequence20.AllocationIntermediateCharacteristicsUNIT12

Multimedia1Theword“multimedia”isbeingusedtodescribeamixtureofhardware,softwareandapplications,withaconsequentconfusioninpeople’smindsastowhatitis2.Itisaconfusionsituationthatcouldleadtoamissedopportunityforindustrytodevelopanewmarketplace.Thetermmultimedialiterallymeansmanyformsofcommunicationandinasensewehavealwaysbeenimmersedinamultimediaenvironmentbecausewearebeingsthatrespondtosound,light,touch,andideas.Thisisessentiallyaninteractiveenvironment.multimedian.多媒体describev.描述，形容mixturen.混合，混合物consequenta.作为结果的，随之发生的confusionn.混，混乱状态opportunityn.机会，良机literallyad.逐字地，字面地inasense从某种意义上说immersev.沉浸，使陷入environmentn.环境，周围Inthemodernpresentationofmultimediawenowhavethetechnologythatcanbegintomovetowardsanability,alreadyheldbythehumanbeing,inthatbyusingcomputertechnology,suchasCD-ROM,notonlycanwebringtogetheraudioandvisualimagesbutalsobeinteractivewithothercomputerusers3.presentationn.呈现，展示visuala.视觉的audioa.听觉的，声音的Perhapsthebiggestreasonfortheexplosion4ofmultimediaofferingsistheenormousadvancesinpersonaldesktopcomputers.Thiscomputeradvancewouldappeartobringmultimediafacilitieswithinthereach5ofthemajorityofhomesforaboutUS$1000;thissystemmightconsistofahigh-speedprocessorwithhugestoragesofRAMandharddisc,acolourmonitor,CD-ROM,soundsystem,languageandlearningsystemsandWindowsandLotusApplications.Thissortofspecificationisaimedatthepersonal,homecomputermarketandisprobablymoreforgamesandeducation.enormousa.巨大的，庞大的facilityn.设备，工具majorityn.多数ThefirstelementassociatedwithmultimediaisperhapstheCD-ROM,nowconsideredamaturetechnology6.TheCD-ROMisusedtostoredatathatrepresentsvisualimageryandcurrentunitscanstoreupto650Mbytesofdata.ThestandardsofmultimediacanbefoundinwhatisknownastheITUWhiteBoot,whichbringstogethervariousstandardsforCD-COMandvideocompressionanditisessentialthatthesetwoareasofstandardsaretakentogether7.monitora.监视器maturea.成熟的Acrucialelementintheprovisionofmultimediaistheuseofcompressedvideo.WithoutcompressiontheamountofstoragethatwouldhavetobeprovidedbytheCD-ROMwouldbeimmense,oryouwouldonlybeabletostore15secondsofafullmotionpicture.Ifcompressionisappliedtothemotionpicturesexpertsgroup(MPEG-1)standard,thena650MbytesCD-ROMcanholdeither72minutesofvideo,or19hoursofaudio,or7000stillphotographs.representv.描述，讲述compressionn.压缩，浓缩immensea.广大的，巨大的ThestandardsformovingpicturesarebyMPEGasinternationalstandards.ThetwolevelsareMPEG-1,whichsetstheprovisionofconsumerqualityofvideoandaudioandMPEG-2,whichsetsthehigherstandardsforprofessional,broadcastimagesandalsolookstodefinehighdefinitiontelevision8(HDTV).MPEG-2looksatmorethanpictures;itlooksattheassociatedsound,storagemethods,bitratesneeded,codingalgorithms,etc.ModernencodersarenotonlyusedintheCD-ROMarea,butalsoasameansoftransmittingsignals,theyuseanumberofdigitalsignalprocessortoformavisionencoder.photographn.照片professionala.职业的，专业的definitionn.定义，清晰度Ifweconsiderthebusinessareaofmultimediaapplications,theprovisionofvideoiscrucialandthatvideoinformationmustcometouserinrealtimeandthereforebeprocessedinrealtime.Thismeansthatanysystemmustconformto9theCCITTMPEG-2standard.Thetechnologytodothishasmovedontremendouslyinthelastfewyearsduetotheneedtoreducethecostoftransmittingdataoverthenetwork.Theencodersanddecodersforvideoarenowmanufacturedwithaminimumofintegratedcircuits.Whatthentheproblemsforthedesigner?Theindividualelementsofmultimediaarealreadyhandledbyastandardpersonalcomputer,suchthingsasaudio,graphicsandtext,butthemajorchallengeisinrealtimevideo,for10thisisthemajorbusinessrequirementandanecessityifmultimediasystemsaretobecomestandarditemsforthedesktop.Thisrealtimeprocessingrequiresavastamountofdatastorageandthisisafunctionoftheamountofinformationcontainedinacolourpicture11,forinstanceanormal640×480pixelcolourpicturerequireswellover1Mbytesofstoragetogivetherequiredquality,thoughforfullmotionvideothisisincreasedupto100Mbytesofdata.Thespreadofmultimediausersisnotjustafunctionoftechnology,anditiscertainlynotastoppableprocess.Thekeytoitstake-upisinthesuccessfulsellingofvideoandtelevisionservices,whichareoftengatheredunderthegeneraltitleofvideo-on-demand(VOD)interactiveservices.AtypicalVODarchitecturetakestrunkandaccessnetworksintoaccount12.Thevideoserveristhekeytoon-demandservices.Thevideoserverwillstorealargenumberofprogramsthatcanbeinstantlyaccessedbyalargenumberofindividualsubscribers;itisstoredinacompressedformtosavespace.architecturen.结构，组织trunkn.干线instantlyad.立刻，即刻Theuseofmultimediaisincreasingallthetimeanditisestimatedthatintheperiodfrom1991to1998thevolumeofmultimedia,notonlyforpersonalbutalsobusinessuse,willincreasefromzeroto$1.9billionforthesoftwareelementalone13.Multimediaisnolongeratoyoragametechnology.Itismovingintoourlivesinmanyways.Itisaffectingourbanking,shopping,education,andtravelandworkpatterns.Yet,itisanincreasingelementinourlives.estimatev.估计toyn.玩具

UNIT13IPTV1Overthepastfewmonths,therehasbeenincreasedinterestintheuseofIPnetworkstodeliverbroadcast-qualityTV.IPTVisarelativelyrecentbuzzwordhavingemergedonlythreeorfouryearsago2.Inanutshell,itmeansthedeliveryoftelevisionoverInternetProtocol(IP)networks.Butforthetelecommunicationindustry,whichdrivesittothemarket,IPTVmeansmuchmore.buzzwordn.

时髦术语，口号emergev.

出现，浮现nutshelln.极小的东西inanutshell简括地说，一句话marketn.市场Forthem,IPTVisanentirelynewmultimediaexperienceextendingthebordersofconventionalbroadcasttelevision;itisanintegrated,“all-embracing”mediaplatformofferingabundleofdiversecontentandcommunicationservicesfromasingleprovideroverasinglenetworktoasingleuserdeviceallwithasinglepayment3.entirelyad.完全地，全部地experiencen.经历extendv.伸长，延伸bordern.边界integratev.综合，集成embracev.拥抱，怀抱；利用，抓住，采用；包围，包括，包含platformn.平台，站台，讲台bundlen.一捆，一束，一大堆diversea.多种多样的，形形色色的contentn.内容，含量，目录paymentn.支付，支付的款项unreliablea.不可靠的Whyuse30-year-oldtechnologydesignedforslow,unreliable,unicastcommunicationstotransportvideo?TheansweristhatIPisamagicalplatformtobreedsuccessandithasbecometotallypervasive4.ThesecondmotivationisthatIPcanoffermorefunctionalitythantraditionalTV.Theopen,extensiblenatureofIPholdsthepromiseofmanymoreservicesinthefuture.IPinfrastructurealsocanbeleveragedtoprovidevideotelephonyandremotemonitoring,aswellasnewusesofvideowithinapplicationsthathaven’tbeenthoughtofyet5.Thefinalfactorthatisemergingiscostsavings.unreliablea.不可靠的unicasta.单播的magicala.迷人的，神秘的，有魔力的breedv.养育，培养，教养pervasivea.遍布的，充满的motivationn.动力，动机，诱因functionalityn.功能extensiblea.可延伸的，可扩展的promisen.允诺，诺言；出息，前途infrastructuren.基础结构leveragev.举债经营TherearedivergingviewsaboutwhatIPTVreallymeans6.Tobroadcasters,IPTVissimplyanewemergingplatformfordistributingdigitaltelevisionchannelstohomeconsumersusingaTVscreen.Tothetelecomindustry,IPTVissynonymouswithanewbroadbanddigitaltechnology,offeringvoice,dataandvideo.IPTViscomplementarytoexistingsatellite,cableandterrestrialsystems,althoughinsomecasesitmaybecomeavigorouscompetitortothem.divergev.分叉，分歧；发散distributev.分配，分发，分送；散布synonymousa.同义的complementarya.补充的，补足的terrestriala.地面的vigorousa.朝气蓬勃的Sofar,thetelecomindustryhasmerelybeenprovidingtelecommunicationservicessuchasvoiceconnectionsbetweentwopoints7.Thetelecomcompanieswerenotatallconcernedwiththecontentoftheinformationcarried.TheyarenowgettinginvolvedinIPTVastheyfacingdecreasingsubscriberrevenuesfromtheirtraditionalvoiceandbroadbandcommunication8.Theyareintheprocessofmovingintothecontent-providingdomainwithnorealexpertiseandexperience