简介：Opportunisticnetworksarederivedfromdelaytolerantnetworks,wheremobilenodeshavenoend-to-endconnections.Nodesarerepresentedbypeople,whichmeansthatopportunisticnetworkscanberegardedassocialnetworks.Humanmobilityplaysanimportantroleinaffectingtheperformanceofforwardingprotocolsinsocialnetworks,furthermore,thetrajectoryofpeople'smovementsaredrivenbysocialcharacteristics.However,currentroutingprotocolsrelyonsimplemobilitymodels,andrarelyconsidersocialcharacteristics.Consideringtwoheterogeneousnetworkmodels,ansocialopportunisticnetworksrouting(SONR)wasproposedwhichbringsanadapteddiscreteMarkovchainintonodes'mobilitymodelandcalculatesthetransitionprobabilitybetweensuccessivestatus.ComparisonwasmadebetweenSpray,WaitandEpidemicprotocol.SimulationshowthatSONRcanimproveperformanceondeliveryratio,deliverylatencyandnetworkoverhead,meanwhile.SONRapproachestheperformanceofEpidemicrouting.

简介：这篇文章介绍一台对称的self-electrooptic效果设备(S种子)的基本结构，并且使用Kirchoff的当前的法律和一个完全相等的电容的模型，到分析S-SEED的开关特征。线性近似和N片断近似被利用获得S-SEED的电压时间(vt)和特征。理论分析被模拟验证，并且结果证明S-SEED的开关时间的精确能与线性近似在应用满足要求。而且，模拟把S-SEED的开关特征与不同输入力量和输入对比比率作比较，它表明那增加的输入对比比率是改进S-SEED的开关特征的一个有效方法。

简介：Becauseofitspotentialapplicationsinagriculture,environmentmonitoringandsoon,wirelessundergroundsensornetwork(WUSN)hasbeenresearchedmoreandmoreextensivelyinrecentyears.ThemainandmostimportantdifferenceofWUSNtoterrestrialwirelesssensornetwork(WSN)isthechannelcharacteristics,whichdeterminesthedesignmethodologyofit.Inthispaper,thepropagationcharacterofelectromagnetic(EM)waveinthenearsurfaceWUSNisanalyzed,aswellasthepathlossmodelofitisgiven.Inaddition,theinfluenceofhuman'sankletothechannelcharacteristicsofnearsurfaceWUSNisinvestigatedbyelectromagnetictheoryanalysis,simulationandexperiment.AnovelpathlossmodelofnearsurfaceWUSNwhichtakestheinterferenceofhuman'sankleintoconsiderationisproposed.ItisverifiedthattheexistingofhumanabovetheWUSNsystemmaycauseadditionalattenuationtothesignalofnearsurfaceWUSNwhichpropagatesaslateralwavealongtheground.Moreover,therelationoftheattenuationandoperatingfrequencyisdeduced,whichgivesareferencetoextendthefrequencybandappliedinWUSN.

简介：广泛的室内的隧道大小与宽带在北京被进行多重输入多重产量(MIMO)在5.25GHz更健全。line-of-sight(LOS)和non-line-of-sight(NLOS)繁殖在室内的办公室和热点情形里被测量。根据测量数据，统计隧道特征在这篇文章被介绍，包括损失(PL)建模的实验路径，三个过量延期参数，圆形的方位角传播(CAS)，和圆形的举起传播了(CES)。在二种情形的不同繁殖机制的比较分析被进行。这些值为国际活动电信进展(IMT进展)为室内的范围和MIMO和直角的频率部门multiplexing(OFDM)的技术研究是重要的系统。

简介：Theeffectofthespatialcharacteristicsofantennaarrayonsmartantennasystemscannotbeneglected.Inthepaper,therelationbetweenspatialcorrelationandinter-antennadistance,impingingangle,anglespreadisfirstinvestigated.Withthesamebeamformingalgorithm,wesimulatetheperformanceofsmartantennasystemwithdifferentAngleSpread(AS)valuesontheconditionsofidealandrealAngleofArrival(AOA)estimation.TheresultsshowthatwiththeidealAOAestimation,theAOAisenoughaccuratetoguaranteethatthesystemonlyhaslittleperformancedegradationeveninthecaseof20degreeeASvaluewhiletherealAOAestimationinfluencedbychannelenvironmentdegradestheperformanceveryobviously,uptoabout7dB.

简介：TheradiatedfieldsGaussianDistributedAperture(GDA)canbeapproximatelyanalyzedbytheComplexRayMethod(CRM).Inthisarticle,theradiatedfieldsderivedintermsofplanewavespectrumintegralareusedasstandard,andtheerrorsourceofthereplacementbycomplexrayfieldsisfound.WithdiscussionsontheerrorcharacteristicsofthisCRMapproximation,conclusionsaredrawnwhichareexpectedtobehelpfulinapplicationsofCRM.

简介：这篇文章集中于识别分享文件对等(P2P)(例如BitTorrent(BT))在一个树桩网络的边阶的交通。由分析应用程序的协议和交通，一个单身的用户的分享文件的P2P交通与极大地不同，这被发现传统并且另外的P2P(例如QQ)申请在深奥远程主机和遥远的端口的分发的交通。因此，一个方法基于远程主机(RHD)的组件和遥远的港口(RPD)的组件被建议识别象BT一样交通。这个方法仅仅在一个树桩网络依靠每台用户主机的流动信息，并且没有包收费载重需要被监视。在间隔，为并发的传播控制协议的立刻的RHD和为每台主机的用户数据包协议流动通过由每流动的远程主机属于的树桩网络组织流动分别地是计算的。在给定的条件上，立刻的RPD通过由遥远的港口组织流动修改立刻的RHD被计算。一位主人是否一直在使用象BT一样应用，能为时间的一个时期从立刻的RHD或平均RHD被推出。基于交通，特征是对比基于内容的方法识别变化多端的分享文件的P2P交通合适的更多的建议方法。试验性的结果证明这个方法与高精确性是有效的。

简介：Inthisarticle,resultsobtainedfromwidebandmultiple-inputmultiple-outputchannelmeasurementsat4.9GHzarepresented.Measurementswereperformedinanindoorhotspotscenariowithbothline-of-sightandnon-line-of-sightpropagationconditions.Verticalpolarizeduniformlineararrays(ULAs)withdifferentantennaspacingandorientationwereutilizedforinvestigatingtheimpactofantennaconfigurationsonthesystemperformance.Basedonmeasuredchannelimpulseresponses,thespatialcorrelationofULAisanalyzedandcomparedwiththetheoreticalvaluescalculatedfromthepowerazimuthspectrum.Followingthat,theeigenvaluestatisticsandcapacitywithrespecttoantennaspacingandorientationaregivenandcompared.Thediversity-multiplexingtradeoff(DMT)ofmeasuredchannelsatoperationalsignal-to-noiseratio(SNR)isalsopresented.ThereasonwhytheDMTofmeasuredchannelsismuchlowerthanthatofi.i.d.Rayleighchannelsisspecified.