信息类专业英语翻译

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1、Dynamictopology:Asthechannelofcommunicationchanges,someoftheneighborswhowerereachableonthepreviouschannelmightnotbereachableonthecurrentchannelandviceversa.Asaresultthetopologyofthenetworkchangeswiththechangeinfrequencyofoperationresultinginroutefailur

2、esandpacketloss.Heterogeneity:Differentchannelsmaysupportdifferenttransmissionranges,dataratesanddelaycharacteristics.Spectrum-Handoffdelay:ForeachtransitionfromonechanneltoanotherchannelduetothePU’sactivity,thereisadelayinvolvedinthetransitioncalledSp

3、ectrum-Handoffdelay.Allthesefactorsdecreasethepredictabilityofthecauseoftransit-delayandsubsequentpacketlossonthenetwork.Thetimelatencyduringchannelhand-offincognitivenetworksmightcausetheTCProundtriptimertotimeout.TCPwillwronglyrecognizethedelaysandlo

4、ssesduetotheabovefactorsasnetworkcongestionandimmediatelytakestepstoreducethecongestionwindowsizeknowingnotthecauseofpacketdelay.Thisreducestheefficiencyoftheprotocolinsuchenvironments.动态技术：随着信道通信的变化，一些邻进信道的用户在原信道没有发生变化而在新信道发生变化，或者相反。随着操作频段的变化，网络的拓扑结构发

5、生变化导致路由失败和丢包。异构：不同的信道支持不同的传输范围，传输速率，延迟特点。频谱切换延迟：由于主用户的出现，每个从一个信道切换到另一个信道，在过渡中，一种延迟被包括叫做频谱切换延迟。所有因素减少了在网络中，传输延迟和随后丢包的原因的预测性。在认知网络的信道切换过程中潜在的时间引起TCP的RTT的超时。TCP错误的认为延迟和丢包由于以上因素比如网络拥塞和立刻采取减少拥塞窗口大小，而不知道包延迟的原因。这些降低协议在这样环境的效率。Throughputmaximizationisoneofthem

6、ainchallengesincognitiveradioadhocnetworks,wheretheavailabilityoflocalspectrumresourcesmaychangefromtimetotimeandhopbyhop.Forthisreason,across-layeropportunisticspectrumaccessanddynamicroutingalgorithmforcognitiveradionetworksisproposed,whichiscalledth

7、eroutinganddynamicspectrumallocation(ROSA)algorithm.Throughlocalcontrolactions,ROSAaimstomaximizethenetworkthroughputbyperformingjointrouting,dynamicspectrumallocation,scheduling,andtransmitpowercontrol.Specifically,thealgorithmdynamicallyallocatesspec

8、trumresourcestomaximizethecapacityoflinkswithoutgeneratingharmfulinterferencetootheruserswhileguaranteeingaboundedbiterrorrate(BER)forthereceiver.Inaddition,thealgorithmaimstomaximizetheweightedsumofdifferentialbacklogstostabilizethesys