简介:这篇文章在继电器在使隧道褪色的瑞利上联网的decode-and-forward(DF)在总数力量限制下面为机会主义的接力赛学习停止性能的靠近形式的表达式,假设多重天线在继电器节点是可得到的。根据是否即时signal-to-noise比率(SNR)或平均SNR能最好为继电器选择,二个机会主义的继电器计划,机会主义的多天线继电器选择(OMRS)和一般水准被利用继电器选择(ABRS)被建议。二个计划的表演借助于理论分析和模拟被评估。OMRS在多天线继电器选择计划之中是停止最佳的并且仔细接近作为理论知道的beamforming(BF)计划,这被观察停止最佳。与相比以前的单个天线的机会主义的中继(或)计划,OMRS带给显著性能改进,它从联合的最大的比率(MRC)和beamforming技术被获得。在不对称的隧道的ABRS的表演在低、中部的SNR范围接近OMRS,这也被显示出。
简介:Asscheduled,the2008BeijingOlympictorchrelayeditsLhasajourneyonJune21~(st).TherelayinTibethad156torchbearersincluding75Tibetansandcovered9.3kilometers.
简介:这篇论文学习多重输入多重输出(MIMO)同时的无线信息和力量转移(SWIPT)继电器系统,在哪个来源节点(SN)同时把信息和精力送到继电器节点(RN),并且RN以收获精力为动力把收到的信号提交给目的地节点(DN)。特别地,我们认为二SWIPT是接收装置图案,也就是切开的力量(PS)和切换的天线(作为)在继电器系统。为每个图案,反复的算法基于凸的优化技术被建议最大化系统率。而且,基于AS计划,我们为非最优的PS比率被给的PS计划建议一个低复杂性优化方法以便寻求在计算复杂性和系统性能之间的平衡。数字结果被提供为MIMOSWIPT继电器系统评估建议算法的表演。建议非最优的方法的表演接近最佳的PS计划的,这被显示出。
简介:Distributedgeneration(DG)willchangecharacteristicsofpowerflowandfaultsoftraditionaldistributionnetworkaswellasthenetworkoperationmode,especiallytheoperationofrelayprotectionandautomaticcircuitbreakerre-closing.Inthispaper,thecharacteristicsandinfluencesofseveraltypesofdistributedgenerationandconnectionpattern,relayprotectionandautomaticcircuitbreakerre-closingareanalyzed.Standardsofrelayprotectionwhendistributedgenerationaccesstodistributionnetworkarediscussedaswell.
简介:Customers'satisfactionwithservicesisreflectedbyqualityofexperience(QoE).Insofar,moststudiesoncooperativecommunicationhavebeenfocusedonimprovingtheQoEofsourceusers.However,theimprovementofasourceuser'sQoEisobtainedatcostofdegradationoftherelayuser'sQoE.Ontheotherhand,cooperativecommunicationscanachieveperformancesimilartothatofaconventionalmultiple-inputmultiple-output(MIMO)systembyformingvirtualMIMOarrays.Hence,toimprovetheQoEperformanceofrelayusers,thisarticleproposestheconceptofabeliefthresholdatthedestinationuserandanewcooperativeschemebasedonthebeliefthresholddestination(BTD)technique,whilewithoutdecayingtheBERperformanceofthecommunicationsystem.
简介:Thetransmissionantennasofcooperativesystemsarespatiallydistributedonmultiplenodes,sothereceivedsignalcanbeasynchronousduetopropagationdelays.Areceivingschemeforcooperativerelaynetworksisproposed,multipleasynchronoussignalsarereconstructedatthereceiverbyforwardandbackwardinterferencecancellation,whichcanobtaingainsofcooperativetransmissiondiversitywithobviousdelayandwithnorequiringtimingsynchronizationororthogonalchannelizationbetweenrelays.Analysisandsimulationshowthatthebiterrorrate(BER)oftheproposedschemeissimilartoAlamouticode,andtheschemehasthediversityorderoforthogonaltransmissionschemeaccompaniedbyminimalBERlosses.Itisdemonstratedthattheperformancecanbefurtherimprovedbyaddinganerrorcorrectingcode(ECC).
简介:性能分析被介绍为多重输入多重产量(MIMO)采用的继电器隧道与直角的时空块代码(OSTBC)播送天线差异,在来源和目的地与N和Nd天线被装备的地方,并且在在decode-and-forward(DF)操作模式的一个多重天线的继电器的帮助下与对方一起交流。在使隧道褪色的独立,不是必然相同的瑞利上,准确靠近形式的标志错误率(重量的单位)表情被导出因为各种各样的数字调整有或没有直接连接为两个格式化OSTBC传播。为全面系统信号噪音比率(SNR)产生函数(MGF)的片刻也被导出,基于哪个我们在场统一重量的单位分析。完整的空间差异顺序能为DFMIMO被完成的分析表演由采用OSTBC传播并且最大的比率联合(MRC)中继隧道接收。所有分析结果通过比较被证实,结果用MentoCarlo模拟获得了。
简介:Gettingalongwiththeimprovementofgreencommunications,theenergyefficiency(EE)ofwirelessnetworkbecomesmoreandmoreimportant.However,inmulti-relay-assistedsystems,therelatedworkobviouslydependsontheend-to-endperformance,whereasEEofrelayshasnotattractedenoughattention.Theauthorsproposeanorthogonalfrequencydivisionmultiplexing(OFDM)multi-relaysystembasedonamplifyandforward(AF)mode.TakingincorporatingEEandremainingenergyasfactor,decisioncriteriaofattendingcooperationisdesigned.TheEEbasedasynchronouspoweriterationmethodispresented,andtheexistenceandconvergenceofnashequilibrium(NE)isproven.Furthermore,ajointalgorithminsubcarrierpairing,relayselectionandpowerallocationisgiven.Geneticalgorithm(GA)anditerationmethodareintegratedtoimprovetheconvergencespeedadditionally.SimulationdemonstratestheobviousimprovementofEE,decreaseofpowerconsumptionandincreaseoflifetimeinrelaysofthisalgorithmwiththeconstraintofminimumdatatransmissionrate.
简介:Asthesystemperformanceisobviouslyimprovedbyintroducingtheconceptofrelayintothetraditionalorthogonalfrequencydivisionmultipleaccess(OFDMA)systems,resourceschedulinginrelay-enhancedOFDMAsystemsisworthyofbeingstudiedcarefully.Tosolvetheoptimizationproblemofachievingthemaximumthroughputwhilesatisfyingthequalityofservice(QoS)andguaranteeingthefairnessofusers,anovelresourceschedulingschemewithQoSsupportforthedownlinkoftwo-hoprelay-enhancedOFDMAsystemsisproposed.Theproposedscheme,whichisconsideredbothinthefirsttimesub-slotbetweendirectlinkusersandrelaystations,andthesecondtimesub-slotamongrelaylinkusers,takesQoSsupportintoconsideration,aswellasthesystemthroughputandthefairnessforusers.Simulationresultsshowthattheproposedschemehasgoodperformanceinmaximizingsystemthroughputandguaranteeingtheperformanceintheservicedelayandthedatalossrate.
简介:TheBeijinglegofthe2008Olympictorchrelaybe-ganinspring.Alongwiththecitizensinothercities,wewerelongingforadistinctiveandstun-ningtorchrelayintermsoftherouteandthemanycolorfulcer-emonialactivities.Theunprecedentedplantoex-tendthetorchrelaytoMt.Qomolangmawillsurelyattractat-tentionfromallovertheworld.It
简介:Thispaperinvestigatestheperformanceofanunderlaycognitiverelaysystemwheresecondaryusers(SUs)sufferfromaprimaryoutageprobabilityconstraintandspectrum-sharinginterferenceimposedbyaprimaryuser(PU).Inparticular,weconsiderasecondarymulti-relaynetworkoperatingintheselectiondecode-and-forward(SDF)modeandproposeabest-relayselectioncriterionwhichtakesintoaccountthespectrum-sharingconstraintandinterference.Basedontheseassumptions,theclosed-formexpressionoftheoutageprobabilityofsecondarytransmissionsisderived.Wefindthataflooroftheoutageprobabilityoccursinhighsignal-to-noiseratio(SNR)regionsduetothejointeffectoftheconstraintandtheinterferencefromthePU.Inaddition,weproposeageneralizeddefinitionofthediversitygainforsuchsystemsandshowthatafulldiversityorderisachieved.Simulationresultsverifyourtheoreticalsolutions.
简介:系统总是在当前的文学基于完整的交通负担被设计并且优化。然而,实际系统很少在完整的负担正在操作,甚至在山峰交通小时。而不是最大化系统率完成完整的负担,与要求的率最小化transmit力量的一个最佳的精力有效的计划在这篇文章被调查。考虑情形是用物理层网络编码的amplify-and-forward协议的一条双向继电器隧道,在二个结束节点在二timeslots以内经由多重继电器节点交换消息的地方。联合功率分配和继电器选择计划被设计完成最小播送功率。通过凸的优化理论,我们第一证明那个单个继电器选择计划是为物理层网络编码的最精力有效的方法。力量分配的靠近形式的表情也被给。数字模拟在不同计划之中表明设计计划以及比较的表演。
简介:在这份报纸,我们比较了联合网络隧道编码的表演(JNCC)为多点传送当独占时,用低密度同等值支票(LDPC)的继电器网络作为隧道代码编码,Convolutional编码或(XOR)编码的网络在中间的继电器节点使用了。多点传送继电器传播是二个固定继电器节点在第二在作出贡献的传播计划的一种类型在基础收发器车站(BTS)和一双活动车站之间的端对端的传播跳跃。我们认为一个方法和二个方法多点传送评估位错误率(BER)和产量性能的情形。是否使用XOR网络在中间的继电器节点编码,被看了那,一样的传播因此在更少的时间槽变得可能产量性能能被改进。而且我们也在建议系统模型,差异和multiplexing获得在被考虑了讨论了二种可能的情形。它值得通知那BER和产量为LDPC代码完成了比对讨论的所有计划的Convolutional代码好。
简介:合作中继作为一种有效技术新兴在下一代的细胞的网络在高数据率范围上完成要求,象长期的进化进展(LTE进展)一样。在这份报纸,我们在向LTE进展中继细胞的网络的multihop上建议一种分布式的联合继电器节点(RN)选择和力量分配计划,两个都考虑无线隧道状态和RN的剩余精力。我们提出作为一个不安的土匪系统中继细胞的网络的multihop。一阶的有限状态的Markov链被用来描绘变化时间的隧道和剩余精力状态转变。与这随机的优化明确的表达,最佳的政策有戏剧性地减少计算复杂性的indexability性质。模拟结果证明建议计划罐头高效地提高期望的系统报酬,与另外的存在算法相比。