小波包分復用論文-基于小波包分復用技術的多載波通信系統(tǒng)研究

統(tǒng)研究3G通信技術日漸成熟并步入商業(yè)化運營,下一技術的結(jié)合,以其較高的頻譜利用率,良好的抗衰落能力,被認為是下OFDM技術具備更佳的信道適基的選擇以及最優(yōu)基選取方法較復雜等難題一直制約著小波包分復用技術的進一步發(fā)展與應用。本文則針對上述問題,進行了深入而細研究現(xiàn)狀及發(fā)展前景,介紹了時頻分析與小波包理論,并以此為基礎,分析了在多徑衰落信道模型下,子載波基的選取對系統(tǒng)抗干擾性能的影響。給出了頻率彌散信道中子載波基的選取原則,提出以小波包函數(shù)替代傳統(tǒng)OFDM技術中所采用的正弦基作為子載波基進行傳輸,利用小波包函數(shù)良好的自正交性與互正交性,來獲取更優(yōu)的抗噪聲與抗波包基的構(gòu)成原則與選擇方法,針對多載波通信系統(tǒng)的性能要求,選取ICI與ISI聯(lián)合功率及峰均功率比作為度量準則,并將子載波數(shù)目作為搜索約束條件,提出了一種基于根節(jié)點逐級向下按二進支路分解,利用度量準則函數(shù)決定父子節(jié)點間取舍的最優(yōu)基搜索算法,并解決了約束條件下的最優(yōu)基輸出問題。最后在4徑Rayleigh衰落信道模型下的仿真結(jié)果表明:該算法的運算速度優(yōu)于現(xiàn)有的兩種算法,且采用最優(yōu)基結(jié)構(gòu)的系統(tǒng)比全分解結(jié)構(gòu)的系統(tǒng)性能提升約20%。最后,總結(jié)了全文的主要工作,指出了本文研究的局限性與不足之處,展望了小波包分復用技術及多載波通信技術的未來發(fā)展趨勢?！居⑽恼縒iththematurityof3Gcommunicationtechnologyandalreadyintocommercialoperation,thedevelopmentofnextgenerationwirelesscommunicationsystemshavebeenputontheagenda.Advancedmodulationcombinedwithmulti-carriercommunication,withitshighspectralefficiency,goodanti-fadingability,isconsideredasthekeytechnologyinnext-generationwirelesscommunicationsystem.Waveletpacketdivisionmultiplexingdoesnotonlyhavegoodanti-ISI,ICIability,butalsohasbetterabilityofadaptingtothechannelthanOFDMtechnology.However,difficultiesinhighpeaktoaveragepowerratio,sub-carrierbasesselectionandoptimalbasisselectionhasrestrictedthefurtherdevelopmentandapplicationofwaveletpacketdivisionmultiplexing.Thisthesiswilladdresstheaboveissues,andprocessdeepandmeticulousresearch.Thisthesisfirstsummarizedanddescribedthecurrentstatueandfutureprospectsofmulti-carriermodulationandwaveletpacketdivisionmultiplexing,introducesthetime-frequencyanalysisandwaveletpackettheory.Basedonthat,thisthesisanalysedtheanti-interferenceperformance.ofdifferentsub-carrierbasesinmulti-pathfadingchannel,andgiventheselectionprincipleofsub-carrierbasesinfrequencydispersionchannel,waveletpacketfunctionisproposedtoreplacethetraditionalsine-baseusedinOFDMtechnologyfortransmission,usingitsselfandcrossorthogonalitytoobtainbetterperformanceagainstnoiseandinterference.Experimentalresultsdemonstratethefeasibilityandeffectivenessofthismethod.Inthefollowingpart,analyzedthecompositionandselectionprincipleofwaveletpacketbasis,andanovelsearchalgorithmforwaveletpacketbasiswasproposed.Thisalgorithmdecomposesthewholewaveletpacketlibraryfromtoptobottombyitsbinarybranch,useICIandISIintegratedpowerandPeaktoAveragePowerRatio(PAPR)forcompetitivedecisiontoselectoptimalbasis.Finallythealgorithmwastestedin4-pathRayleighfadingchannel.Simulationresultsindicatedthat:theoperationspeedofthealgorithmisbetterthantwoexistingalgorithms,andtheoutputoftheoptimalbasisstructuregainabout20%performanceincreasethanfulldecomposedstructure.Finalchapteristhesummaryofthemainworkandfuturetrendofthewaveletpacketdivisionmultiplexingandmulti-carriercommunicationtechnology.多載波通信子載波基最優(yōu)基峰均功率比正交頻分復用【英文關鍵詞】WaveletpacketdivisionmultiplexingMulti-carriercommunicationSub-carrierbasisOptimalbasispeaktoAveragepowerratioOrthogonalfrequencydivisionmultiplexing【目錄】基于小波包分復用技術的多載波通信系統(tǒng)研究摘要4-5ABSTRACT5第一章緒論8-141.1引言8-91.2研究背景及現(xiàn)狀9-121.2.1多載波調(diào)制技術9-111.2.2小波包分復用技術11-121.3本文的主要內(nèi)容及結(jié)構(gòu)12-14第二章多載波調(diào)制系統(tǒng)14-202.1單載波調(diào)制142.2多載波調(diào)制14-162.2.1多載波調(diào)制的原理14-152.2.2多載波調(diào)制系統(tǒng)的優(yōu)缺點15-162.3多載波調(diào)制系統(tǒng)的實現(xiàn)16-192.3.1MC-CDMA系統(tǒng)16-172.3.2OFDM系統(tǒng)17-182.3.3WPDM系統(tǒng)18-192.4本章小結(jié)19-20第三章小波理論與小波包分復用20-303.1時頻分析與小波理論20-253.1.1Fourier變換20-213.1.2Gabor變換213.1.3小波變換21-243.1.4小波包變換24-253.2小波包分復用系統(tǒng)25-293.2.1小波包分復用系統(tǒng)的原理與結(jié)構(gòu)25-283.2.2WDPM的特點與優(yōu)勢28-293.3本章小結(jié)29-30第四章多載波通信系統(tǒng)中子載波基的選取30-404.1引言30-314.2無線通信信道31-344.2.1無線傳播環(huán)境的多樣性與多徑性31-324.2.2無線信道中的衰落類型32-334.2.3無線信道模型33-344.3子載波基的優(yōu)化選取34-374.3.1問題的提出34-354.3.2信道干擾的理論分析35-364.3.3子載波基的優(yōu)化選取36-374.4仿真分析與結(jié)論37-384.5本章小結(jié)38-40第五章小波包分復用系統(tǒng)中的最優(yōu)小波包基選擇40-515.1引言40-415.2最優(yōu)小波包基的定義41-425.3現(xiàn)有的最優(yōu)基選取方法42-455.3.1最優(yōu)基搜索算法42-435.3.2窮舉算法43-455.4快速