6/6專業英語課程報告-下載Modernmobilecommunicationtechnology

Innowhighlytheinformationizationsociety,theinformationandthecorrespondencehavebecomethemodernsociety“thelife”.Theinformationexchangemainlyreliesonthecomputercorrespondence,butcorrespondstakesthetransmissionmethod,withthesensingtechnology,thecomputertechnologyfusesmutually,hasbecometheinternationalsocietyandtheworldeconomicdevelopmentpowerfulengineinthe21stcentury.Inordertoadaptthetimerequest,thenewgenerationofmobilecommunicationtechnologyseasonableandlives,thenewgenerationofmobilecommunicationtechnologyisthepeoplesaidthatthirdgeneration'scorecharacteristicisthewidebandaddressingturnsonnon-gaproamingbetweentherigidnetworkandnumerousdifferentcommunicationssystem'sgainsthemultimediacommunicationservices.

Alongwiththetimeprogress,thetechnicalinnovation,people'sliferequest'senhancement,themobilecommunicationtechnologyrenewalspeedisquiteastonishing,almosteveryothertenyearmobilecommunicationtechnologyhasatransformationupdate,fromthe1980s“themobilephone”topresent's3Ghandset,duringhashadtwomobilecommunicationtechnologytransformation,transitsfrom1GAMPSto2GGSM,fromGSMtoIMT-2000(i.e.3Gtechnology).Knowsmodernonmethemobilecommunicationtechnologytohavethefollowingseveralaspectimportanttechnology:

1.widebandmodulationandmultipleaccesstechnique

Thewirelesshighspeeddatatransmissioncannotonlydependonthefrequencyspectrumconstantlytheexpansion,shouldbehigherthanthepresentnumbermagnitudeatleastinthefrequencyspectrumefficiency,mayusethreetechnologiesinthephysicallevel,namelyOFDM,UWBandfreetimemodulationcode.OFDMwithotherencodingmethod'sunion,nimblyOFDMandTDMA,FDMA,CDMA,SDMAcombinesthemultipleaccesstechnique.Inthe1960stheOFDMmulti-channeldatatransmissionhassucceededusesinKineplexandtheKathrynhighfrequencymilitary

channels.OFDMhasusedin1.6Mbit/shighbitratedigitalsubscriberline(HDSL),6Mbit/sasymmetricaldigitalsubscriberline(ADSL),100Mbit/sreallyhighspeedfiguresubscriber'sline(VDSL),digitalaudiofrequencybroadcastanddigitalvideobroadcastandsoon.OFDMapplieson5GHzprovides54Mbit/swirelesslocalnetworkIEEE802.11aandIEEE802.11g,highperformancethisregionnetworkHiperLAN/2andETSI-BRAN,butalsotakesmetropolitanareanetworkIEEE802.16andtheintegratedservicedigitbroadcast(ISDB-T)thestandard.Compareswiththesingleloadfrequencymodulationsystemservicepattern,theOFDMmodulationservicepatternneedstosolvetherelativelybigpeakevenpowerratio(PAPR,PeaktoAveragePowerRatio)andtothefrequencyshiftingandthephasenoisesensitivequestion.Highspeedmobilecommunication'sanotherrequestisunderthewidenoisebandwidth,mustdemodulatethesignal-to-noiseratiotoreduceasfaraspossible,thusincreasesthecoverarea.Mayadopttheanti-fadingthefullstartpowercontrolandthepilotfrequencyauxiliaryfasttrackdemodulationtechnology,likethefrequencyrangeanti-fading'sRakereceiveandthetracktechnology,theOFDMAtechnologywhichdeclinesfromthetimedomainandthefrequencyrangeresistancetimeandthefrequencyselectivity,thelinkauto-adaptedtechnology,theunioncodingtechnique.

2.frequencyspectrumusefactorlifttechnique

Thefundamentalresearchpointedout:IntheindependentRayleighscatteringchannel,thedatarateandtheantennaseveraltenthlinearrelationships,thecapacitymayreachShannon90%.Islaunchingandthereceivingendmayobtainthecapacityandthefrequencyspectrumefficiencygainbythemulti-antennadevelopmentchannelspace.TheMIMOtechnologymainlyincludesthespatialmultiplyingandthespacediversitytechnology,concurrentorthesalvosameinformationenhancesthetransmissionreliabilityontheindependentchannel.Receivesanddispatchesthebilateralspacediversityisthehigh-capacitywirelesscommunicationsystemusesoneoftechnical.BellLabfreetime'soppositeangleBLAST(D-BLAST)capacityincreasetoreceiveanddispatchthebilateralsmallestantennanumberinadministrativelevelsthefunction.Thecrosstimedomainwhichandtheairzone

expansionsignalconstitutesusingMIMOmayalsoresistthemulti-diameterdisturbance.V-BLASTsystemwhenindoor24~34dB,thefrequencyspectrumusefactoris20~40bit/s/Hz.Butlaunchesandthereceivingenduses16antennas,when30dB,thefrequencyspectrumusefactorincreasesto60~70bit/s/Hz.Thesmartantennaautomatictrackingneedsthesignalandtheauto-adaptedfreetimeprocessingalgorithm,producesthedimensionalorientationwavebeamusingtheantennaarray,causesthemainwavebeamalignmentsubscribersignaldirectionofarrivalthroughthedigitalsignalprocessingtechnology,thesidelobeorzerofallsthealignmentunwantedsignaldirectionofarrival.Theauto-adaptedarrayantennas(AAA,AdaptiveArrayAntennas)disturbsthecounter-balancebalancer(ICE,InterferenceCancelingEqualizer)tobepossibletoreducedisturbsandcutstheemissivepower.

3.softwareradiotechnology

Thesoftwareradiotechnologyisinthehardwareplatformthroughthesoftwareeditionbyaterminalimplementationdifferentsysteminmanykindsofcommunicationservices.Itusesthedigitalsignalprocessinglanguagedescriptiontelecommunicationpart,downloadsthedigitalsignalprocessinghardwarebythesoftwareroutine(DSPH,DigitalSignalPocessingHardware).Byhasthegeneralopeningwirelessstructure(OWA,OpenWirelessArchitecture),compatiblemanykindsofpatternsbetweenmanykindsoftechnicalstandardsseamlesscut.UWBisalsocalledthepulsetoberadio,themodulationusesthepulsewidthinthenanosecondlevelfastriseandthedroppulse,thepulsecoverfrequencyspectrumfromthecocurrenttotheluckyhertz,doesnotneedintheradiofrequencywhichtheconventionnarrowbandfrequencymodulationneedstotransform,afterpulseformation,maydeliverdirectlytotheantennalaunch.

4.networksecurityandQoS

QoSdividesintowirelessandthewiredsidetwoparts,wirelessside'sQoSinvolvestheradioresourcemanagementandthedispatch,theadmissioncontrolandthemobilitymanagementandsoon,themobilitymanagementmainlyincludestheterminalmobility,individualmobilityandservicemobility.Wiredside'sQoSinvolvesbasedontheIPdiffSerdiscriminationserviceandtheRSVPend-to-end

resourcesreservationmechanism.MechanismmapsthewirelesssideIPdiffSerIPtheQoS.Networksecurityincludingnetworkturningonsecurity,corenetworksecurity,applicationsecurity,safetymechanismvisibilityandconfigurable.

Intheabovemodernmobilecommunicationkeytechnologies'sfoundation,hashadthelandhoneycombmobilecommunication,thesatellitecommunicationaswellasthewirelessInternetcommunication,thesemailingaddresscausedthecorrespondenceappearancetohavethehugechange,usedthedigitaltechniquethemodernwirelesscommunicationalreadytopermeatethenationaleconomyeachdomainandpeople'sdailylife,forthisreason,weneededtocarethatitstrendofdevelopment,hopeditdevelopedtowardmoreandmoreconvenientpeople'slife'sdirection,willletnowushavealookatthemodernmobilecommunicationthefuturetrendofdevelopment.Modernmobilecommunicationtechnologicaldevelopmentsevennewtendencies:First,mobilitymanagementalreadyfromterminalmanagementtoindividualmanagementandintelligentmanagementdevelopment;Second,networkalreadyfromsynchronizeddigitalcircuittoasynchronousdigitalgroupingandasynchronoustransfermode(ATM)development;Thethree,software'sdevelopmentsactuatedfromthealgorithmtotheprocedure-orientedandfacethegoaltendencydevelopment;Thefour,informationprocessinghavedevelopedfromthevoicetothedataandtheimage;Thefive,wirelessfrequencyspectrumprocessingalreadyfromnarrowbandsimulationtothenarrowbandCDMAdevelopment;Thesix,computershavedevelopedfromcentralprocessingtothedistributionalserverandintellectualizedprocessing;Theseven,semiconductordeviceshavedevelopedfromeachchip16,000,000,000,000/150MHzspeedVLSIto0.5/350MHzspeedVLSIand2,000,000,000,000,000/550MHzspeedVLSI.

Underthistendency'sguidance,themobileservicerapiddevelopment,itsatisfiedthepeopleinanytime,anyplacetocarryonthecorrespondencewithanyindividualthedesire.Themobilecommunicationrealizesinthefuturetheidealperson-to-personcommunicationservicewaythatmustbetaken.Intheinformationsupporttechnology,themarketcompetitionandunderthedemandcombinedaction,themobilecommunicationtechnology'sdevelopmentisprogressesbyleapsand

bounds,presentsthefollowingseveralgeneraltrends:1)networkservicedigitization,grouping;2)networkingwideband;3)networkingintellectualization;4)higherfrequencyband;5)moreeffectiveusefrequency;6)eachkindofnetworktendsthefusion.Theunderstanding,graspsthesetendencieshasthevitalpracticalsignificancetothemobilecommunicationoperatorandtheequipmentmanufacturer.

譯文：

現代移動通信技術

在當今高度信息化的社會，信息和通信已成為現代社會的“命脈”。信息的交流主要依賴于計算機通信，而通信作為傳輸手段，與傳感技術、計算機技術

相互融合，已成為21世紀國際社會和世界經濟發展的強大動力。為了適應時代的要求，新的一代移動通信技術應時而生，新的一代移動通信技術即人們稱之第三代的核心特征是寬帶尋址接入到固定網和眾多不同通信系統間的無隙縫漫游，獲取多媒體通信業務。

隨著時代的進步、科技的創新、人們的生活要求的提高，移動通信技術更

新換代速度相當驚人，差不多每隔十年移動通信技術就發生一次變革性換代，

從上個世紀80年代的“大哥大”到現在的3G手機，其間發生了兩次移動通信技術的變革，從1G的AMPS過渡到2G的GSM，從GSM到IMT-2000（即3G技術）。就我所知現代的移動通信技術有以下幾方面的重要技術：

1、寬帶調制和多址技術

無線高速數據傳輸不能一味僅靠頻譜的擴展，應在頻譜效率上至少高于目

前一個數量級，可在物理層采用三項技術，即OFDM、UWB和空時調制編碼。OFDM與其他編碼方式的結合，靈活把OFDM與

TDMA、FDMA、CDMA、SDMA組合成多址技術。20世紀60年代OFDM的多路數據傳輸已成功用于Kineplex和Kathryn高頻軍事通信系統。OFDM已用于1.6Mbit/s高比特率數字用戶線（HDSL），6Mbit/s不對稱數字用戶線（ADSL），100Mbit/s甚高速數字用戶線（VDSL），數字音頻廣播和數字視頻廣播等。OFDM應用于5GHz上提供54Mbit/s無線本地網IEEE802.11a和

IEEE802.11g，高性能本地域網絡HiperLAN/2和ETSI-BRAN，還作為城域網IEEE802.16和集成業務數字廣播（ISDB-T）標準。與單載頻調制制式相比，OFDM調制制式要解決相對大的峰均功率比（PAPR，PeaktoAveragePowerRatio）和對頻率位移和相位噪聲敏感的問題。高速移動通信的另一要求是在寬噪聲帶寬下，所需解調信噪比應盡可能降低，從而增加覆蓋面積。可采取抗

衰落的快速發射功率控制和導頻輔助快速跟蹤相干解調技術，如頻域抗衰落的Rake接收和跟蹤技術，從時域和頻域抵抗時間和頻率選擇性衰落的OFDMA技術，鏈路自適應技術，聯合編碼技術。

2、頻譜利用率提升技術

理論研究指出：在獨立Rayleigh散射信道中，數據速率與天線數成線性關系，容量可達Shannon的90%。在發射和接收端以多天線開發信道空間可取得容量和頻譜效率的增益。MIMO技術主要包括空間復用和空間分集技術，在獨立信道上并發或連發相同信息來提高傳輸可靠性。收發雙方的空間分集是高

容量無線通信系統采用技術之一。貝爾實驗室分層次空時的對角BLAST（D-BLAST）容量的增加為收發雙方最小天線數的函數。利用MIMO所構成的跨時域和空域的擴展信號還可以抵抗多徑干擾。V-BLAST系統在室內24～34dB時，頻譜利用率為20～40bit/s/Hz。而發射和接收端均采用16天線，在30dB時，頻譜利用率增至60～70bit/s/Hz。智能天線自動跟蹤所需信號和自適應空時處理算法，利用天線陣產生空間定向波束，通過數字信號處理技術使主波束對準

用戶信號到達方向，旁瓣或零陷對準干擾信號到達方向。自適應陣列天線（AAA，AdaptiveArrayAntennas）中干擾抵消均衡器（ICE，InterferenceCancelingEqualizer）可減少干擾和降低發射功率