外文翻译--基于mimo-ofdm系统的正交空时分组码【适用于毕业论文外文翻译】

外文翻译基于MIMOOFDM系统的正交空时分组码【适用于毕业论文外文翻译】外文资料（一）ONORTHOGONALSPACETIMEBLOCKCODESFORMIMOOFDMSYSTEMSSPACETIMECODEINMOBILECOMMUNICATIONSYSTEM,ANDORTHOGONALDESINGINMULTIPLEANTENNASSCNEMEAREDICSUSSEDBYTHEMETHODS,DATAISENCODEDUSINGASPACETIMEBLOCKCODEANDISSPLITINTOSEVERALSTREAMSWHICHARESIMULTANEOUSLYTRANSMITTEDBYANTENNASSOAMAXIMUMLIKELIHOODDECODINGALGORITHMCANBEUSEDATTHERECEIVERTOACHIEVETHEMAXIMUMDIVERSITYORDERINTRODUCTIONMOSTWORKONWIRELESSCOMMUNICATIONSHADFOCUSEDONHAVINGANANTENNAARRAYATONLYONEENDOFTHEWIRELESSLINKUSUALLYATTHERECEIVERSEMINALPAPERSBYGERARDJFOSCHINIANDMICHAELJGANS1,FOSCHINI2ANDEMRETELATAR3ENLARGEDTHESCOPEOFWIRELESSCOMMUNICATIONPOSSIBILITIESBYSHOWINGTHATFORTHEHIGHLYSCATTERINGENVIRONMENTSUBSTANTIALCAPACITYGAINSAREENABLEDWHENANTENNAARRAYSAREUSEDATBOTHENDSOFALINKANALTERNATIVEAPPROACHTOUTILIZINGMULTIPLEANTENNASRELIESONHAVINGMULTIPLETRANSMITANTENNASANDONLYOPTIONALLYMULTIPLERECEIVEANTENNASPROPOSEDBYVAHIDTAROKH,NAMBISESHADRIANDROBERTCALDERBANK,THESESPACETIMECODESSTCSACHIEVESIGNIFICANTERRORRATEIMPROVEMENTSOVERSINGLEANTENNASYSTEMSTHEIRORIGINALSCHEMEWASBASEDONTRELLISCODESBUTTHESIMPLERBLOCKCODESWEREUTILIZEDBYSIAVASHALAMOUTI,ANDLATERVAHIDTAROKH,HAMIDJAFARKHANIANDROBERTCALDERBANKTODEVELOPSPACETIMEBLOCKCODESSTBCS4STCINVOLVESTHETRANSMISSIONOFMULTIPLEREDUNDANTCOPIESOFDATATOCOMPENSATEFORFADINGANDTHERMALNOISEINTHEHOPETHATSOMEOFTHEMMAYARRIVEATTHERECEIVERINABETTERSTATETHANOTHERSINTHECASEOFSTBCINPARTICULAR,THEDATASTREAMTOBETRANSMITTEDISENCODEDINBLOCKS,WHICHAREDISTRIBUTEDAMONGSPACEDANTENNASANDACROSSTIMEWHILEITISNECESSARYTOHAVEMULTIPLETRANSMITANTENNAS,ITISNOTNECESSARYTOHAVEMULTIPLERECEIVEANTENNAS,ALTHOUGHTODOSOIMPROVESPERFORMANCETHISPROCESSOFRECEIVINGDIVERSECOPIESOFTHEDATAISKNOWNASDIVERSITYRECEPTIONANDISWHATWASLARGELYSTUDIEDUNTILFOSCHINIS1998PAPERANSTBCISUSUALLYREPRESENTEDBYAMATRIXEACHROWREPRESENTSATIMESLOTANDEACHCOLUMNREPRESENTSONEANTENNASTRANSMISSIONSOVERTIMEHERE,SIJISTHEMODULATEDSYMBOLTOBETRANSMITTEDINTIMESLOTIFROMANTENNAJTHEREARETOBETTIMESLOTSANDNTTRANSMITANTENNASASWELLASNRRECEIVEANTENNASTHISBLOCKISUSUALLYCONSIDEREDTOBEOFLENGTHTTHECODERATEOFANSTBCMEASURESHOWMANYSYMBOLSPERTIMESLOTITTRANSMITSONAVERAGEOVERTHECOURSEOFONEBLOCKIFABLOCKENCODESKSYMBOLS,THECODERATEISRKTONLYONESTANDARDSTBCCANACHIEVEFULLRATERATE1ALAMOUTISCODEORTHOGONALITYSTBCSASORIGINALLYINTRODUCED,ANDASUSUALLYSTUDIED,AREORTHOGONALTHISMEANSTHATTHESTBCISDESIGNEDSUCHTHATTHEVECTORSREPRESENTINGANYPAIROFCOLUMNSTAKENFROMTHECODINGMATRIXISORTHOGONALTHERESULTOFTHISISSIMPLE,LINEAR,OPTIMALDECODINGATTHERECEIVERITSMOSTSERIOUSDISADVANTAGEISTHATALLBUTONEOFTHECODESTHATSATISFYTHISCRITERIONMUSTSACRIFICESOMEPROPORTIONOFTHEIRDATARATESEEALAMOUTISCODEMOREOVER,THEREEXISTQUASIORTHOGONALSTBCSTHATACHIEVEHIGHERDATARATESATTHECOSTOFINTERSYMBOLINTERFERENCEISITHUS,THEIRERRORRATEPERFORMANCEISLOWERBOUNDEDBYTHEONEOFORTHOGONALRATE1STBCS,THATPROVIDEISIFREETRANSMISSIONSDUETOORTHOGONALITYHIGHERORDERSTBCSTAROKHETALDISCOVEREDASETOFSTBCSTHATAREPARTICULARLYSTRAIGHTFORWARD,ANDCOINEDTHESCHEMESNAMETHEYALSOPROVEDTHATNOCODEFORMORETHAN2TRANSMITANTENNASCOULDACHIEVEFULLRATETHEIRCODESHAVESINCEBEENIMPROVEDUPONBOTHBYTHEORIGINALAUTHORSANDBYMANYOTHERSNEVERTHELESS,THEYSERVEASCLEAREXAMPLESOFWHYTHERATECANNOTREACH1,ANDWHATOTHERPROBLEMSMUSTBESOLVEDTOPRODUCEGOODSTBCSTHEYALSODEMONSTRATEDTHESIMPLE,LINEARDECODINGSCHEMETHATGOESWITHTHEIRCODESUNDERPERFECTCHANNELSTATEINFORMATIONASSUMPTION4TRANSMITANTENNASTWOSTRAIGHTFORWARDCODESFOR4TRANSMITANTENNASAREC4，1/2C1C2C3C4C1C2C3C4C2C1C4C3C2C1C4C3C3C4C1C2C3C4C1C2C4C3C2C1C4C3C2C1ANDC4,3/4C1C2C32C32C2C1C3C32C322C32C1CC2C22C2C2C1C1212C32C2C2C1C12CCC2C2112C3THESECODESACHIEVERATE1/2ANDRATE3/4RESPECTIVELY,ASFORTHEIR3ANTENNACOUNTERPARTSC4,3/4EXHIBITSTHESAMEUNEVENPOWERPROBLEMSASC3,3/4ANIMPROVEDVERSIONOFC4,3/4ISC1C2C30C2C10C3C4,3/4C30C1C20C3C2C1WHICHHASEQUALPOWERFROMALLANTENNASINALLTIMESLOTSDECODINGONEPARTICULARLYATTRACTIVEFEATUREOFORTHOGONALSTBCSISTHATMAXIMUMLIKELIHOODDECODINGCANBEACHIEVEDATTHERECEIVERWITHONLYLINEARPROCESSINGINORDERTOCONSIDERADECODINGMETHOD,AMODELOFTHEWIRELESSCOMMUNICATIONSSYSTEMISNEEDEDATTIMET,THESIGNALRTIRECEIVEDATANTENNAJISRTIJSTINTJ,JI1NTWHEREIJISTHEPATHGAINFROMTRANSMITANTENNAITORECEIVEANTENNAJ,STIISTHESIGNALTRANSMITTEDBYTRANSMITANTENNAIANDNTJISASAMPLEOFADDITIVEWHITEGAUSSIANNOISEAWGNTHEMAXIMUMLIKELIHOODDETECTIONRULEISTOFORMTHEDECISIONVARIABLESRIRTJTIJTIT1J1NTNRWHEREKIISTHESIGNOFSIINTHEKTHROWOFTHECODINGMATRIX,KPQDENOTESTHATSPISUPTOASIGNDIFFERENCE,THEK,QELEMENTOFTHECODINGMATRIX,FORI1,2NTANDTHENDECIDEONCONSTELLATIONSYMBOLSITHATSATISFIESARGMINRCWHC2ARGMINRHARGMIN2RERHCWHHHCWCWH2HRHCWHHHCWCWH,WITHTHECONSTELLATIONALPHABETDESPITEITSAPPEARANCE,THISISASIMPLE,LINEARDECODINGSCHEMETHATPROVIDESMAXIMALDIVERSITYREFERENCES1GERARDJFOSCHINIANDMICHAELJGANSJANUARY1998ONLIMITSOFWIRELESSCOMMUNICATIONSINAFADINGENVIRONMENTWHENUSINGMULTIPLEANTENNASWIRELESSPERSONALCOMMUNICATIONS633113352GERARDJFOSCHINIAUTUMN1996LAYEREDSPACETIMEARCHITECTUREFORWIRELESSCOMMUNICATIONSINAFADINGENVIRONMENTWHENUSINGMULTIELEMENTANTENNASBELLLABSTECHNICALJOURNAL1241593IEMRETELATARNOVEMBER1999CAPACITYOFMULTIANTENNAEUROPEANTRANSACTIONSONTELECOMMUNICATIONS,1065855954VAHIDTAROKH,NAMBISESHADRI,ANDARCALDERBANKMARCH1998“SPACETIMECODESFORHIGHDATARATEWIRELESSCOMMUNICATIONPERFORMANCEANALYSISANDCODECONSTRUCTION“IEEETRANSACTIONSONINFORMATIONTHEORY442744765译文基于MIMOOFDM系统的正交空时分组码本文介绍了移动通信中的空时码,针对多天线系统提出了空时分组码的正交设计理论,可以采用高效的调制技术QAM,PSK,由多天线同时发射。接收端采用最大似然译码可以获得最大的分集增益。并因空时码有很高的频谱利用率,从而使空时码在未来移动通信及无线局域岗中得到广泛的应用。介绍ALAMOUTI于1998年提出了一种发射端采用两根天线的空时分组码方案,该方案能够实现最大分集增益和全发射速率,在接收端使用了简单的最大似然译码。为了将空时分组码推广到多个天线,VAHIDTAROKH等基于满分集提出了正交空时分组码。由于正交空时分组编码发射矩阵各行之间的正交性,可以获得满分集增益,但是当发射天线数大于2时,利用复正交设计得到的正交空时分组编码不能达到最大传输速率。为此,HJAFARKHAN等和TIRKKONEN等分别提出了两种基于全速率的准正交空时分组编码,即JAFARKHANI码和TBH码。JIAHOU等在JAFARKHANI码和TBH码的基础上,讨论了变形JAFARKHANI码和变形TBH码,并提出了2种新的准正交编码。在既定的情况下,在特定的数据流传输编码在BLOCKS块,间隔,将分布在天线和跨越时空。虽然是必要的,它有多个发射天线,这是没有必要有多个接收天线,虽然这样做改进效能。这个过程接收不同的数据备份,是众所周知的最大似然译码,直到1998年FOSCHINI研究论文。空时编码通常用矩阵来表示。在矩阵中，每一行代表一个时间段,而每一列代表每一根天线的传输。正交由于最初的对空时编码做出的研究,并介绍了这样的正交。这意味着,例如既定设计向量任何两个柱代表掠正交编码矩阵。这是简单的结果,线性,最佳解码的接收机。最严重的不利因素是所有之一,同时满足这一标准法典,必须牺牲一些比例的数据传输速率。此外,存在着在利率,以达到更高的数据传输干扰的成本ISI。因此,他们的误码率是空时编码的界定标准之一,正交率提供免费传授由于正交码。高阶空时编码方法TAROKHETAL等在1998年10月发现了一组空时编码。这是特意直截了当的以创造了这个方案的创始人名字为名。他们也证明了不能超过2个发射天线可以达到的目标。他们的代码。一直以来的改进。然而,作为明确的例子,为什么不能到达率1,其他什么必须解决的问题有如何用空时码接收更好的信号。他们也体现了简单的，直线解码是伴随着他们的编码方案,在完美的信道状态信息。4个发射天线两个直截了当的代码为4发射天线是C1C2C3C4C1C2C3C4C2C1C4C3C2C1C4C3C3C4C1C2C3C4C1C2C4，1/2C4C3C2C1C4C3C2C1以及C4,3/4C1C2C32C32C2C1C3C32C322C32C1CC2C22C2C2C1C1212C32C2C2C1C12CCC2C2112C3这些编码实现1/2比特和3/4比特的空时编码,C1C2C30C2C10C3C4,3/4C30C1C20C3,C2C1从所有具有相同能力的天线可知。译码一个特别吸引人的特征的正交STBC就是这个了最大似然解码,可以较好地实现在接收者对而已线性加工。为了考虑解码方法,无线通信系统的模型是必需的。在时间T上的信号,RTJ天线接收到的是RTIJSTINTJ,JI1NT是路径获得传送天线吗接收天线STI是信号通过传送天线I和NTJ有一份添加剂白色高斯噪声检测规则的就是要形成的决策变量。RIRTJTIJTIT1J1NTNR满足对于准正交空时分组编码而言,由于发射矩阵的各行不是完全正交的,因此在接收端进行最大似然译码时需对信号进行联合检测,这就使得其译码算法较之正交空时分组编码要复杂一些。由最大似然准则,其解码过程即求ARGMINRCWHC2ARGMINRHARGMIN2RERHCWHHHCWCWH2HRHCWHHHCWCWH是映射后的符号。虽然从表面上看,这是一个简单的直线解码方案,其中,C提供最大的似然性。参考文献1GERARDJFOSCHINIANDMICHAELJGANSJANUARY1998“ONLIMITSOFWIRELESSCOMMUNICATIONSINAFADINGENVIRONMENTWHENUSINGMULTIPLEANTENNAS“WIRELESSPERSONALCOMMUNICATIONS633113352GERARDJFOSCHINIAUTUMN1996“LAYEREDSPACETIMEARCHITECTUREFORWIRELESSCOMMUNICATIONSINAFADINGENVIRONMENTWHENUSINGMULTIELEMENTANTENNAS“BELLLABSTECHNICALJOURNAL1241593IEMRETELATARNOVEMBER1999“CAPACITYOFMULTIANTENNAGAUSSIANCHANNELS“EUROPEANTRANSACTIONSONTELECOMMUNICATIONS,1065855954VAHIDTAROKH,NAMBISESHADRI,ANDARCALDERBANKMARCH1998“SPACETIMECODESFORHIGHDATARATEWIRELESSCOMMUNICATIONPERFORMANCEANALYSISANDCODECONSTRUCTION“IEEETRANSACTIONSONINFORMATIONTHEORY442744765外文资料（二）UNITRATECOMPLEXORTHOGONALSPACETIMEBLOCKCODECONCATENATEDWITHTURBOCODINGSPACETIMEBLOCKSTBCODEHASBEENANEFFECTIVETRANSMITDIVERSITYTECHNIQUEFORCOMBATINGFADINGDUETOITSORTHOGONALDESIGN，SIMPLEDECODINGANDHIGHDIVERSITYGINSINTHISPAPER,AUNITRATECOMPLEXORTHOGONALSTBCODEFORMULTIPLEANTENNASINTIMEDIVISIONDUPLEXTDDMODEISPROPOSEDMEANWHILE,TURBOCODINGTCISEMPLOYEDTOIMPROVETHEPERFORMANCEOFPROPOSEDSTBCODEFURTHERBYUTILIZINGITSGOODABILITYTOCOMBATTHEBURSTERROROFFADINGCHANNELCOMPAREDWITHFULLDIVERSITYMULTIPLEANTENNASSTBCODES,THEPROPOSEDCODECANIMPLEMENTUNITRATEANDPARTIALDIVERSITYANDITHAYMUCHSMALLERCOMPUTATIONALCOMPLEXITYUNDERTHESAMESYSTEMTHROUGHPUTMOREOVER,THEAPPLICATIONOFTCCANEFFECTIVELYMAKEUPFORTHEPERFORMANCELOSSDUETOPARTIALDIVERSITYSIMULATIONRESULTSSHOWTHATONTHECONDITIONOFSAMESYSTEMTHROUGHPUTANDCONCATENATIONOFTC,THEPROPOSEDCODEHASLOWERBITERRORRATEBERTHANTHOSEFULLDIVERSITYCODESINTRODUCTIONRECENTLY,TRANSMITDIVERSITYHASBEENSTUDIEDEXTENSIVELYASAMETHODOFCOMBATINGDETRIMENTALEFFECTSINWIRELESSFADINGCHANNELSDUETOITSRELATIVESIMPLICITYOFIMPLEMENTANDFEASIBILITYOFHAVINGMULTIPLEANTENNASATTHEBASESTATIONBSASIMPLETRANSMITTERDIVERSITYSCHEMEUSINGTW0TRANSMITANTENNASISPROPOSEDBYALAMOUTIANEXTENSIONTOMORETHANTWOTRANSMITANTENNASISPRESENTED,WHEREITISSHOWNTHATTHEALAMOUTISCHEMEISASPECIALCASEOFSPACETIMEBLOCKSTBCODETHESTBCODESCHEMECANACHIEVEFULLTRANSMITDIVERSITYANDHASASIMPLEMAXIMUMLIKELIHOODMLDECODINGALGORITHMWHILEUSEDATTHEDECODERFORTHIS,STBCODEISANATTRACTIVEAPPROACHFORPRACTICALPURPOSESBUT,ITISPROVEDTHATFORSTBCODE,ACOMPLEXORTHOGONALDESIGNWHICHPROVIDEFULLDIVERSITYANDUNITRATEISNOTPOSSIBLEFORMORETHANTWOANTENNAS,ANDTHE1/2RATEOR3/4RATESTBCODEFORTHREEANDFOURTRANSMITANTENNAS4TXAREALSOGIVENWITHTHECODERATE1AND2/3RATESTBCODEFORFIVETRANSMITANTENNASISPROPOSEDRECENTLYCONSIDERINGTHEFULLRATEISTHEIMPORTANTMEANSTOIMPLEMENTHIGHDATARATESERVICEANDVERYIMPORTANTFORLOWSIGNALTONOISERATIOSSNRSUNITRATECOMPLEXORTHOGONALSTBCODE1FULLDIVERSITYSTBCODESREVIEWINTHISSUBSECTION,WEREVIEWTHEBASICPRINCIPLEOFSTBCODETHATPROVIDESMAXIMUMPOSSIBLEDIVERSITYFORMULTIPLETRANSMITANTENNASINWIRELESSCOMMUNICATIONSLETL,MANDTBEPOSITIVEINTEGERS,ACOMPLEXORTHOGONALSTBCODEISDEFINEDBYATMDIMENSIONALTRANSMISSIONMATRIXG,EVERYENTRYOFWHICHISCOMPLEXLINEARCOMBINATIONOFTHEINPUTSYMBOLSS1,S2,S3,SL,ANDTHEIRCONJUGATESS1,S2,S3,SL,ANDITSATISFIESTHEFOLLOWINGCOMPLEXORTHOGONALCONDITIONGG|SL|IMMHL1L2WHERESUPERSCRIPT“H“DENOTESTHEHERMITIANCONJUGATIONANDIISTHEMMIDENTITYMATRIXMANDTARETHENUMBERSOFTRANSMITTINGANTENNAANDTIMESLOTSUSEDTOTRANSMITLINPUTSYMBOLS,RESPECTIVELY2UNITRATESTBCODEINTHISSUBSECTION,WECONSIDERACOMMUNICATIONSYSTEMCOMPRISING3TRANSMITANTENNAAND1RECEIVEANTENNATHATOPERATESINARAYLEIGHOFANALYSISTHETRANSMITTERANDRECEIVERSTRUCTURESOFTHECOMMUNICATIONSYSTEMWITHTCARESHOWNINFIG1ANDFIG2,RESPECTIVELYTHEDATASOURCEBITSAREFIRSTLYENCODEDBYTHETURBOENCODER,THENAREMAPPEDINTOCORRESPONDINGCONSTELLATIONSYMBOLSTHESYMBOLSARESTBENCODED,THERESULTINGENCODEDSYMBOLSAREMODULATEDONTOAPULSEWAVEFORMANDTHENTRANSMITTEDFROMTHREETRANSMITANTENNASRESPECTIVELYFIG1FIG2INTDDMODEL,THECHANNELGAINESTIMATEDBYTHEUPLINKCANBEUSEDTODOWNLINKTRANSMISSION,SOWECANCHOOSETWOMAXIMUMCHANNELGAINAMPLITUDESFROMESTIMATEDTHREEANTENNACHANNELGAINS,ANDUSECORRESPONDINGTWOTRANSMITANTENNASTOTRANSMITTHECODEDSYMBOLS,RESPECTIVELYNAMELY,IF|H1|H3|AND|H2|H3|,WECHOOSETXLANDTX2TOTRANSMITSYMBOLSSIMILARLY,THEOTHERTWOCASESAREALSOEASYTOANALYSISHERE,LETHM1ANDHM2DENOTETHETWOCHOSENMAXIMUMCHANNELGAINS,RESPECTIVELYTHENATTHERECEIVER,THERECEIVEDSIGNALMATRIXATTIMESLOT1ANDSLOT2CANBEEXPRESSEDBYRR1EG2HNR2SHM1N1SE212S2S1HM2N2ITCANBECHANGEDASHM1RR1E/2R2HM2E/2HSNHM2S1N1HM1S2N2THENORMALIZEDCONSTANTISUSEDTOKEEPTHETOTALTRANSMITTEDENERGYBEE,HERE21/2,EISTHETRANSMITTEDENERGYATEACHTRANSMISSIONINTERVALNISTHE21WHITENOISEMATRIX，THESNRISDEFINEDASE/NOTHEELEMENTSOFHCANBEOBTAINEDFROMTHEESTIMATEDCHANNELGAINCOEFFICIENTSINTHEUPLINKBYTHEUSEOFTDDMODECONSIDERINGHHH|HM1|2|HM2|2I22THEN,SN1HM2211N2HM2HRE/2|HM1|HM2|S2N1HM2N2HM1HTHUSTHEDECODINGCANBEPERFORMEDVIALINEARCOMBININGANDMAXIMUMLIKELIHOODDECISIONASFOLLOWSR1REG2HNR2SHM1N1SE/212NHSS21M22REFERENCES123SIAVASHMALAMOUTIASIMPLETRANSMITDIVERSITYTECHNIQUEFORWIRELESSVTAROKHHJAFARKHANIARCALDERBANKSPACETIMEBLOCKCODESFROMXUEBINLIANGAHIGHRATEORTHOGONALSPACETIMEBLOCKCODE200305COMMUNICATIONS199808ORTHOGONALDESIGNS1999074THLIEWLHANZOSPACETIMECODESANDCONCATENATEDCHANNELCODESFORWIRELESSCOMMUNICATIONS2002025CBERROUAGLAVIEUXNEAROPTIMUMERRORCORRECTINGCODINGANDDECODINGTURBOCODES1996译文单位抗衰落复正交空时分组码级联的TURBO码空时编码因其正交性简单解码和高分集增益是一种防止衰落的有效的发射变化技术。在本文中，假设对于多个天线的时分双工模型有一个单位速率的复正交空时编码。同时，使用TURBO码通过利用其良好的性能来改进所假设的空时分组码的抵抗衰落信道的突发的错误的能力。与全样性的多天线空时分组码相比，所假设的码能够有单位速率以及部分的多样性，并且它在相同的系统吞吐量时计算复杂性要小的多。更好的是，因其部分多样性，TURBO码的应用能有效的弥补性能损失。仿真结果表明在相同的系统的吞吐量以及TURBO码串连情况下，所假设的码相对于那些全样性的码有更加低的误码率。介绍近年来，因在基站使用的简单性和多天线的灵活性，传送多样性作为在衰落信道中抵抗严重衰落的方法而被广泛研究。ALAMOUTI建议一种用两个天线的简易传送多样性计划。一种对超过两个传送天线的引申也产生了，它显示出ALAMOUTI是空时分组编码的一种特殊例子。这个空时分组编码能够达到传送全样性并且在译码时有最大的解码可能性。因此，空时分组码是一种有实用性的很有吸引力的编码方式。然而，对于正交分组码。对于超过两个天线的复正交设计，提供全传送和单位速率是不大可能的，对于三根或四根天线1/2速率或者3/4速