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Lesson13About4G
(第十三課關(guān)于4G)
Vocabulary(詞匯)ImportantSentences(重點(diǎn)句)QuestionsandAnswers(問(wèn)答)Problems(問(wèn)題)
Eachmajorevolutioninmobilephonetechnologyhasbeenmarkedbyageneration.Currentlythethirdgeneration,betterknownas3G,istakingtheworldbystorm.However,manyindustryexpertshavepredictedthat4Gisjustaroundthecorner,sowhatis4G?1MobileGenerations
Thefirstwaveofmobilephonetechnologywashardlymobilebytoday’sstandards.Phonesweresolargethattheywerebuiltintobriefcase-likecarriersforeasyportability.Aroundthesametime,carphonesmadetheirdebut,sotelecommunicationnetworksweregearedtowardsservicingboththesedevices.Thenetworkswerepurelyanalogue,andwerenowhereclosetothekindoftechnologythatisnowvisible.However,althoughthedeviceswereextremelycumbersome,theyheraldedtheageofthenewertechnologythatissoprevalenttoday.Thesecondgenerationofmobilephonetechnologyisstillvisibleinmobilesnow,becausethesecondmajorinnovationwastheintroductionoftheGlobalSystemforMobileCommunications.PopularlyknownasGSM,thisstandardssystemalloweduserstocarrytheirmobilesacrosscountriesandstillhavenetworkaccess.Thesecondgenerationofmobileswasconsiderablysmaller,asmobilecircuitrybecamemoresophisticated.2The3GRevolution
Oncemobilesbecameapracticalnecessity,andalmosteveryonehadone,thenextgreatinnovationwasturningamobilephoneintoaminiaturepersonalcomputer.GPRS(GeneralPacketRadioService)cameaboutduringthesecondgeneration,butthetrueproliferationofmobileInternetwasbroughtonbyEDGE(EnhancedDataRatesforGSMEvolution).Thenewadvancessparkedbetterconnectivity,betterdownloadspeedsandtheoverallimprovedavailabilityofmobiledatanetworks.Eachgenerationspannedaconsiderablenumberofyears.Therewereanumberofimprovementsandinnovationsthatwereintroduced,howeveronlythereallymajoronesweremarkedwithachangeingeneration.Mostofthesmalleronesreceivedanacknowledgmentbychangingthedecimalvalueofthegeneration.[1]3Whatis4G?
MobileInternetstillfeaturesasamajorfactorforinnovation,asitstillcannothopetorivalthePC-boundInternetexperience.4Gisgoingtointroducewirelesstechnologiestomainstreammobilephones.Since4Ghasnotbeenofficiallydefinedbyanyone,thereisalotofspeculationastowhatexactlywillconstitute4Gmobiletechnology.Therearevariouscontendersfortherole;twoofthefrontrunnersbeingWiMAXandLTE.
However,boththetechnologieshaveonecommonfactorwhichseemstounanimouslyheraldtheonsetof4G:orthogonalfrequency-divisionmultiplexingorOFDM.[2]4OFDM
Currently,thereareanumberofwaysthatdataistransferredfromdevicetodevice.CDMA(codedivisionmultipleaccess)isonepopulartechnology,andTDMA(timedivisionmultipleaccess)isasecond.CDMAtransfersanumberofdifferentdatapacketsononechannel,usingcodestodistinguishbetweendifferentreceivers.TDMA,ontheotherhand,againusesonechannelbutallotseachdifferentdatapacketatimeslot.OFDMdiffersfromthesetechnologiessignificantly;thechannelitselfisdividedintonarrowbands,anddatapacketsaresentthrougheachbandindividually.Thismethodprovestobemuchmoreefficientthanthepreviouslyusedtechnologies,henceitisconsideredtobeanintegralpartofthe4Grevolution.Readmore:/mobile/emerging-platforms/
articles/69017.aspx#ixzz0s2PVb72m5WiMAX
WiMAX,simplyput,isbroadbandonawirelessconnection.TheexistenceofWiMAXwillensurethathigh-speedInternetaccessisavailableanywhereausergoes.Thehardwareisstillinthedesignstages,becausetheadoptionofthistechnologywillentailahugeoverhaulofexistingtelecommunicationnetworks.High-speedInternetaccesswilldrasticallychangeauser’smobileInternetexperience.Asitstands,theuserisrestrictedtocertainwebinteractionslikeuploadingphotosorvideos,andmaybeupdatingablogonceinawhile.Thedatatransferratesprevalentareexorbitantandthereforedatatransferisseverelylimited.Theimplementationofhigh-speeddataaccessonmobilephoneswillfinallycatapultthemobilephoneintoseriouscontentioninthepersonalcomputersegment.6LTE:Long-TermEvolution
Developedbythe3GPP(ThirdGenerationPartnershipProject)group,LTEisanewwirelessbroadbandtechnologythatdiffersfromWiMAX.LTEplacesgreatemphasisonIPaddresses,sinceitiscloselybasedupontheTCP/IPnetworkingskeleton.TheideaistocreateenoughIPaddressessothateachdevicehasauniqueone.HoweverthemainfocusofLTEisthatitisshapinguptobehighperformanceineveryway.Thetechnologyisn’tfullydevelopedasyet,butthecharacteristicsthatareemergingpromisegreatthings:highpeakratesfordatatransmission,reducedlatencyandscalablebandwidth.
AnimportantfeatureofLTEistheabilitytoco-existharmoniouslywithpreviousarchitectures.ThereforeaLTE-enablednetworkcanpassdatabackandforthfromaCDMAnetworkseamlessly.7iPhone4G
HotontheheelsoftheiPadrelease,iPhone4Ghandsetshavebeenrumouredforreleasethissummer.Everyyear,sincethefirstiPhonehandsetwaslaunched,therehasbeenanewversionofthephonereleasedregularly.Thisyearpromisestobenodifferent.Speculationisrifethatthe4GtackedontheendofthenewiPhonemeansthatthehandsetmayjustbe4Genabled.Theargumentposedhereisthatthe3Gmodelwasactuallythesecondphone,soitisprobablynotaversionnumberaspreviouslythought.
Applehasn’tconfirmedordeniedanythingasyet;thenewiPhonemaynotbe4Gatall,butanHD(highdefinition)model.ThisscenarioiscertainlymorecredibleastheimprovementsrequiredfortheiPhonetomeritthe4Gtagwillbequitesubstantial.84GisMAGIC
4Gnetworksarestillinthefluidstagesofdevelopment.Asofnow,itissometimesreferredtoasMAGIC(Mobilemultimedia,Anytime/any-where,Globalmobilitysupport,IntegratedwirelessandCustomizedpersonalservice)–whichbodeswellforamobilephoneuser.Itwillbeinterestingtowatchthetechnologiesunfoldoverthecourseofthenextfewmonths.1.
aroundthecorner即將到來(lái)。
2.
Markn.標(biāo)志,分?jǐn)?shù),痕跡,記號(hào)vt.做標(biāo)記于,打分?jǐn)?shù),標(biāo)志vi.作記號(hào)。
3.
hardlyadv.剛剛,幾乎不,僅,嚴(yán)厲的,艱辛的。
4.
carriern.運(yùn)送者,郵遞員,帶菌者,行李架,搬運(yùn)器,航空母艦,[電]載波(信號(hào))。
5.
analoguen.相似物,類似物,類似語(yǔ);同源語(yǔ),相似器官;相似體;類比,比擬;模擬(量,裝置,設(shè)備,系統(tǒng),計(jì)算機(jī))。Vocabulary6.
heraldn.使者,傳令官,通報(bào)者,先驅(qū),預(yù)兆vt.預(yù)報(bào),宣布,傳達(dá),歡呼。
7.
comeabout出現(xiàn),發(fā)生。
8.
proliferationn.增殖,分芽繁殖。
9.
spann.跨度,跨距,范圍v.橫越。
10.
speculationn.思考,思索;構(gòu)思;推測(cè)。
11.?unanimously
adv.無(wú)異議地;全體一致地。12.?onsetn.開(kāi)始,開(kāi)端,發(fā)生,肇始(尤指不快的事件);攻擊,襲擊;【醫(yī)】發(fā)病。
13.?overhaul
vt.徹底檢查,大修;趕上,追上;超越;徹底革新或改革。
14.?exorbitant
adj.過(guò)度的,極高的。
15.?catapult
n.(小孩玩的)彈弓;石弩,弩炮vt.用弩炮發(fā)射,猛力推出;猛力推動(dòng)。[1]Eachgenerationspannedaconsiderablenumberofyears.Therewereanumberofimprovementsandinnovationsthatwereintroduced,howeveronlythereallymajoronesweremarkedwithachangeingeneration.Mostofthesmalleronesreceivedanacknowledgmentbychangingthedecimalvalueofthegeneration.
每一代都會(huì)跨越許多年。對(duì)于其間的一些改進(jìn)和革新,僅把那些真正重要的進(jìn)展用作換代的標(biāo)志。多數(shù)受到承認(rèn)的較小的進(jìn)展則用小數(shù)表示。注意,最后的句子的謂語(yǔ)(weremarked)省略了。ImportantSentences
[2]However,boththetechnologieshaveonecommonfactorwhichseemstounanimouslyheraldtheonsetof4G:orthogonalfrequency-divisionmultiplexingorOFDM.
但是兩種技術(shù)有一個(gè)共同的要素,這個(gè)要素看來(lái)無(wú)異議地預(yù)示著4G的有力開(kāi)端,這就是正交頻分復(fù)用,或者OFDM。(1)
Whichiswrongaboutmobilegenerations?()
A.
Eachmajorevolutioninmobilephonetechnologyhasbeenmarkedbyageneration.
B.
Thesecondgenerationofmobilephonetechnologyisstillvisibleinmobilesnow.
C.
GPRS(GeneralPacketRadioService)isonetechnologyof3G.
D.
Whatexactlywillconstitute4Gmobiletechnologyhasnotbeenofficiallydefined.QuestionsandAnswers(2)
Whichiswrongabout4G?()
A.
WiMAXandLTEarethecontendersfor4G.
B.
OFDMunani
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