简介:随着IPv6标准的成熟和第三代移动通信(3G)的发展,在3G中承载数据业务的IP承载网采用IPv6将是必然的发展趋势。文章首先介绍了IPv6相对于IPv4的一些新特点,同时介绍了3G的体系结构,然后对IPv6的这些新特点住3G中应用的进行分忻。最后总结了IPv6对3G发展的影响。
简介:Digitalcircuitsoperatinginthesub-thresholdregimeconsumetheleastenergy.Thestrictenergyconstraintsaredesiredintheapplicationswhichworkatthelowestpossiblesupplyvoltage.Ontheotherhand,theconventionaldesignflowutilizesthetechnologylibraryprovidedbythefoundrywithafixedvoltageboundary,whichcausesproblemswhenthesupplyscalesdowntothesub-thresholdregime.Inthispaper,wepresentadesignmethodologytocharacterizetheexistingcelllibrarywithLibertyNCXtofacilitatethestandarddesignflow.Itisdemonstratedin0.13mcomplementarymetal-oxide-semiconductor(CMOS)technologywiththesupplyvoltageof300mV.
简介:摘要:移动通信网络数据流量的爆炸式增长、海量物联网设备的互联互通以及新业务、新场景、新应用、新需求的不断涌现,促使着无线通信技术以前所未有的速度演进升级。无线通信技术的演进升级和互联网技术的蓬勃发展,给人类社会发展与技术进步带来了深刻的变革,为全球经济业界预计和社会进步做出卓越贡献。与5G技术相比,6G将在流量密度、连接数密度和能量效率等多个性能指标方面大幅度提升。由于物理层的关键技术是影响无线通信网络效果的重要因素,因此对于6G无线通信网络,要进一步做好对物理层的关键技术分析,强化6G无线通信的能力,使6G网络向着更高的安全通信和高效通信的目标前进。文章介绍了6G无线通信网络的技术优势,并对6G无线通信网络物理层的关键技术进行探究,,希望为未来6G物理层相关研究提供一定的参考。
简介:Asapromisingtechniquetoenhancethespatialresolutionofremotesensingimagery,sub-pixelmappingisprocessedbasedonthespatialdependencetheorywiththeassumptionthatthelandcoverisspatiallydependentbothwithinpixelsandbetweenthem.Thespatialattractionisusedasatooltodescribethedependence.First,thespatialattractionsbetweenpixels,subpixel/pixelspatialattractionmodel(SPSAM),aredescribedbythemodifiedSPSAM(MSPSAM)thatestimatestheattractionsaccordingtothedistributionofsub-pixelswithinneighboringpixels.Thenamixedspatialattractionmodel(MSAM)forsub-pixelmappingisproposedthatintegratesthespatialattractionsbothwithinpixelsandbetweenthem.AccordingtotheexpressionoftheMSAMmaximumisingthespatialattraction,thegeneticalgorithmisemployedtosearchtheoptimumsolutionandgeneratethesub-pixelmappingresults.ExperimentsshowthatcomparedwithSPSAM,MSPSAMandpixelswappingalgorithmmodifiedbyinitializationfromSPSAM(MPS),MSAMcanprovidehigheraccuracyandmorerationalsub-pixelmappingresults.
简介:ThemajordrawbackinOrthogonalFrequencyDivisionMultiplexing(OFDM)systemisduetothehighPeak-to-AveragePowerRatio(PAPR),sotheperformanceofthesystemissignificantlydegradedbythenonlinearityofaHighPowerAmplifier(HPA)inthetransmitter.Inordertomitigatedistortion,ablockcodingschemeforreducingPAPRinOFDMsystemswithlargenumberofsubcarriersbasedoncomplementarysequencesandpredistortionisproposed,whichiscapableofbotherrorcorrectionandPAPRreduction.ComputersimulationresultsshowthattheproposedschemesignificantlyimprovesBitErrorRate(BER)performanceascomparedtoanuncodedsystemwhenanHPAisemployedoracodedsystemwithoutpredistortion.
简介:Itisprovedthatisa(Δ+1)-colorablegraph,soarethegraphsG×PnandC×Cn,wherePnandCnarerespectivelythepathandcyclewithnvertices,andΔthemaximumedgedegreeofthegraph.TheexactchromaticnumbersoftheproductgraphsPr1×Pr2×…×PrnandC3k×C2m1×C2m2×…×C2mnarealsopresented.Thusthetltalcoloringconjectureisprovedtobetrueformanyothergraphs.
简介:EstimationprecisionofDisplacedPhaseCenterAlgorithm(DPCA)isaffectedbythenumberofdisplacedphasecenterpairs,thebandwidthoftransmittingsignalandmanyotherfactors.DetailedanalysisismadeonDPCA'sestimationprecision.AnalysisresultsshowthatthedirectionalvectorestimationprecisionofDPCAislow,whichwillproduceaccumulatingerrorswhenphasecen-ters'trackisestimated.Becauseofthisreason,DPCAsuffersfromaccumulatingerrorsseriously.Toovercomethisproblem,amethodcombiningDPCAwithSubApertureImageCorrelation(SAIC)ispresented.Largesyntheticapertureisdividedintosub-apertures.Microerrorsinsub-apertureareestimatedbyDPCAandcompensatedtorawechodata.Bulkerrorsbetweensub-aperturesareesti-matedbySAICandcompensateddirectlytosub-apertureimages.Afterthat,sub-apertureimagesaredirectlyusedtogenerateultimateSASimage.Themethodisappliedtothelake-trialdatasetofa20kHzSASprototypesystem.ResultsshowthemethodcansuccessfullyremovetheaccumulatingerrorandproduceabetterSASimage.
简介:<正>日前,德州仪器(TI)宣布推出一款SimpleLinkSub-1GHzCC1200收发器,进一步壮大其高性能RF产品线阵营。该CC1200具有业界领先的覆盖范围与共存性,以及高达1Mbps的数据速率,专门针对高级电表基础设施(AMI)及家域网(HAN)的1GHz以下无线连接而开发,可充分满足智能电网、家庭楼宇自动化以及告警与安全系统应用需求。CC1200支持嗅探模式与快速建立时间,可通过低功耗工作提供长达数年的电池使用寿命。CC1200是一款高度灵活的RF解决方案,支持原有1GHz以下系统、所有具有硬件数据包处理与硬件AES安全支持的IEEE802.15.4gFSK模式,以及所有无线M-Bus(wM-Bus)模式。