协同通信与AF和DF中继协议详情.docx
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协同通信与AF和DF中继协议详情
Abstract
Nowadays,thereisatrendforcommunicationsystemthatthewholenetworksystemisbecomingdynamicsothattherearealwayshavingdevicesshouldbeembeddedandremoved.Conventionalwiredcommunication,duetothecomplexityofcabling,doesnotadapttothemoderncommunicationsystem.Wirelesstechniquehasbeenusedwidelybecausedevicescanbeconnectedbyelectromagnetismwavewithoutcabling.However,lowtransmittingreliablitybecauseofinter-interferencebetweenelectromagnetismwavesisthekeyproblemofwirelesscommunication.Basedonthis,thisthesisinvestigatesoneofthetechniquecalledcooperativecommunicationanditcooperativeprotocols.
Cooperativecommunicationisavirtualmultiple-inputmultiple-output(MIMO)system.Toincreasethereliabilityofsignaltransmittedwithoutincreasingtheamountofcommunicationdevices,thistechnologytriestomakeeachantennashaveoneormorepartnersthatassistthemtotransmitthesignal.Inwirelessnetwork,thedevicesnotonlytransmittheirownsignalbutalsoassisttheir“partner”totransmittheirsignalforsavingthecostofinstallationofadditionalantennasatbothreceiverandsender
Inthisthesis,wefocusonintroducingthreemainprotocolsincooperativecommunication:
Amplify-and–Forward(AF),Decode-and-Forward(DF)andCodedCooperation(CC).TheperformanceandmathematicalequationsofAFandDFareanalysed,andthenMATLABprogramswerecreatedtosimulatetheperformanceofthesetwoprotocols.
Aboutthethreeprotocols,themainproceduresarealsointroduced.TheperformancecomparisonforAFandDFindifferentsignal-to-noise(SNR)aredemonstrated.TheresultpresentsthattheDFprotocolshasbetterperformancethanAF.Finally,somerecommendationsandfutureworkarementionedattheendofthethesis.
TableofContents
Abstract
Tableofcontains
Listoffigures
ListofabbreviationsandSymbols
1Introduction..................................................................................................................................9
1.1Background.......................................................................................................................9
1.2Objectives.........................................................................................................................9
1.3Approaches.......................................................................................................................9
1.4Thesisoutline....................................................................................................................10
2LiteratureReview.......................................................................................................................12
2.1Overview...........................................................................................................................12
2.2Spatialdiversitytechnology..............................................................................................13
2.3BasicModelforWireless...................................................................................................13
2.3.1SISOsystem............................................................................................................13
2.3.2MIMOsystem.........................................................................................................14
2.3.3Cooperativemodel.................................................................................................14
2.4Cooperativeschemes........................................................................................................15
2.4.1Amplify-and-forwardmethod................................................................................16
2.4.2Decode-and-forwardmethod................................................................................16
2.4.3Codedcooperation.................................................................................................17
3SimulationandAnalysesofAF..................................................................................................21
3.1Overview...........................................................................................................................21
3.2Maximumlikelihoodmethod............................................................................................21
3.3SimulationandAnalysis.....................................................................................................21
3.3.1Thewholeprocedureandanalysis.........................................................................21
3.3.2Simulation..............................................................................................................24
3.4Summary...........................................................................................................................26
4SimulationandAnalysisofDF...................................................................................................27
4.1Overview..........................................................................................................................27
4.2Quantizationmethod.......................................................................................................27
4.3ConvolutionalCodeandViterbidecode..........................................................................27
4.3.1Convolutionalcode...............................................................................................28
4.3.2Viterbidecode.......................................................................................................28
4.4Simulationandanalysis....................................................................................................28
4.4.1Thewholeprocedureandanalysis........................................................................29
4.4.2Simulation..............................................................................................................30
4.5PerformancecomparisonbetweenAFandDF................................................................31
4.6Mainchallenges................................................................................................................32
4.7Summary...........................................................................................................................33
5Conclusionsandfuturework.....................................................................................................34
5.1Conclusion.........................................................................................................................34
5.2Prospect............................................................................................................................34
5.3Futurework.......................................................................................................................35
Reference...................................................................................................................36
AppendixAThesisspecification..................................................................................37
AppendixBLogbookSummarySignature....................................................................40
AppendixCMATLABprograms....................................................................................41
C.1Amplify-and-ForwardProtocol……………………………………………………………….........……41
C.2Decode-and–Forwardprotocol……………………………………………………..................……42
C.3Rayleighchannel………………………………………………………......................................…..45
ListofFigures
Figure2.1virtualMIMOsystem………………………………………………………………………............….….…..13
Figure2.2Cooperativecommunication………………………………………………………………………….....……14
Figure2.3MIMOsystem…………………………………………………………………………………………….......……..15
Figure2.4Cooperativemodel…………………………………………………………………………………….......……..16
Figure2.5Relayamplifymodel………………………………………………………………………………………...……..17
Figure2.6Decodedandforwardmodel…………………………………………………………………………..……….18
Figure2.7Codedcooperativemodel…………………………………….........………………………………...........19
Figure2.8Codedcooperationdataallocation…………………………………………………………..………...…….20
Figure2.9Fourcasesincodedcooperative……………………………………………………………......……………20
Figure3.1firsttimeslotinAFmethod………………………………………………………………..…......…....…….23
Figure3.2SecondtimeslotinAFmethod………………………………………………………………….……………..24
Figure3.3AFprotocolBERdiagram……………………………………………………………………………………..…..26
Figure4.1(n,k,m)convolutionalencoder…………………………..……………………………………………....…….29
Figure4.2firsttimeslotofDF…………………………………………………………………………………………………….30
Figure4.3Secondtimeslot…………………………………….........…………………………………………………….…..30
Figure4.4DFprotocolBERdiagram……………………………………………………………………………………….....32
Figure4.5DFwholeprocedures……………………………..………………………………………………………...……..32
Figure4.6performancecomparedbetweenAFandDF…….....................………………………….………33
ListofAbbreviationsandSymbols
MIMO
Multipleinputmultipleoutput
SISO
Singleinputsingleoutput
AF
Amplify-and-Forward
DF
Decode-and-Forward
CC
CodedCooperation
BER
Biterrorrate
QPSK
Quadraturephase-shiftkeying
i.i.d
independentlyandidenticallydistribution
ML
Maximumlikelihood
SNR
Signal–noise-ratio
1Introduction
1.1Background
Wirelesscommunicationis,recently,thefastestimprovingsegmentandmostwidelyusedwayofthecommunicationindustry.Forutilizingthebroadcastpropertyofelectromagnetismwave,theinformationcanbetransmittedinwirelessenvironment,whichsavesmuchcostforcablingandmakesthechangeofnetworkstructureeasily.Ontheotherhand,aswirelesstechniqueisusedmorewidely,therearealsomanyproblemsappear