OFDM for Underwater Acoustic Communications

412 Pages·2014·1.08 MB·English

by  Shengli Zhou

OFDM FOR UNDERWATER
ACOUSTIC
COMMUNICATIONS

OFDM FOR UNDERWATER
ACOUSTIC
COMMUNICATIONS
ShengliZhou
UniversityofConnecticut,USA
ZhaohuiWang
MichiganTechnologicalUniversity,USA
Thiseditionfirstpublished2014
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ISBN:9781118458860
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1 2014
To Juanjuan, Daniel, Joyce, and my parents Heting and Caiyun
S. Z.
To my parents Yongcheng and Jiuqin
Z.-H. W.

Contents
Preface xvii
Acronyms xix
Notation xxiii
1 Introduction 1
1.1 BackgroundandContext 1
1.1.1 EarlyExplorationofUnderwaterAcoustics 1
1.1.2 UnderwaterCommunicationMedia 2
1.1.3 UnderwaterSystemsandNetworks 3
1.2 UWAChannelCharacteristics 3
1.2.1 SoundVelocity 3
1.2.2 PropagationLoss 5
1.2.3 Time-VaryingMultipath 7
1.2.4 AcousticPropagationModels 10
1.2.5 AmbientNoiseandExternalInterference 11
1.3 PassbandChannelInput–OutputRelationship 11
1.3.1 LinearTime-VaryingChannelwithPath-SpecificDopplerScales 12
1.3.2 LinearTime-VaryingChannelswithOneCommonDopplerScale 13
1.3.3 LinearTime-InvariantChannel 13
1.3.4 LinearTime-VaryingChannelwithBothAmplitudeandDelay
Variations 14
1.3.5 LinearTime-VaryingChannelwithFrequency-DependentAttenuation 15
1.4 ModulationTechniquesforUWACommunications 15
1.4.1 FrequencyHoppedFSK 15
1.4.2 DirectSequenceSpreadSpectrum 16
1.4.3 SingleCarrierModulation 17
1.4.4 Sweep-SpreadCarrier(S2C)Modulation 18
1.4.5 MulticarrierModulation 18
1.4.6 Multi-InputMulti-OutputTechniques 19
1.4.7 RecentDevelopmentsonUnderwaterAcousticCommunications 20
1.5 OrganizationoftheBook 20
viii Contents
2 OFDMBasics 23
2.1 Zero-PaddedOFDM 23
2.1.1 TransmittedSignal 23
2.1.2 ReceiverProcessing 26
2.2 Cyclic-PrefixedOFDM 27
2.2.1 TransmittedSignal 27
2.2.2 ReceiverProcessing 28
2.3 OFDMRelatedIssues 28
2.3.1 ZP-OFDMversusCP-OFDM 28
2.3.2 Peak-to-Average-PowerRatio 29
2.3.3 PowerSpectrumandBandwidth 29
2.3.4 SubcarrierAssignment 30
2.3.5 OverallDataRate 30
2.3.6 DesignGuidelines 31
2.4 ImplementationviaDiscreteFourierTransform 31
2.5 ChallengesandRemediesforOFDM 32
2.5.1 BenefitsofDiversityCombiningandChannelCoding 33
2.6 MIMOOFDM 36
2.7 BibliographicalNotes 38
3 NonbinaryLDPCCodedOFDM 39
3.1 ChannelCodingforOFDM 39
3.1.1 ChannelCoding 39
3.1.2 CodedModulation 41
3.1.3 CodedOFDM 42
3.2 NonbinaryLDPCCodes 43
3.2.1 NonbinaryRegularCycleCodes 44
3.2.2 NonbinaryIrregularLDPCCodes 45
3.3 Encoding 46
3.4 Decoding 48
3.4.1 Initialization 48
3.4.2 Variable-to-Check-NodeUpdate 49
3.4.3 Check-to-Variable-NodeUpdate 50
3.4.4 TentativeDecisionandDecoderOutputs 51
3.5 CodeDesign 52
3.5.1 DesignofRegularCyclecodes 53
3.5.2 DesignofIrregularLDPCCodes 53
3.5.3 Quasi-CyclicNonbinaryLDPCcodes 55
3.6 SimulationResultsofCodedOFDM 58
3.7 BibliographicalNotes 59
4 PAPRControl 63
4.1 PAPRComparison 63
4.2 PAPRReduction 65
4.2.1 Clipping 65
4.2.2 SelectiveMapping 67
4.2.3 PeakReductionSubcarriers 69
4.3 BibliographicalNotes 69
Contents ix
5 ReceiverOverviewandPreprocessing 71
5.1 OFDMReceiverOverview 72
5.2 ReceiverPreprocessing 73
5.2.1 ReceiverPreprocessing 73
5.2.2 DigitalImplementation 74
5.2.3 Frequency-DomainOversampling 77
5.3 Frequency-DomainInput–OutputRelationship 78
5.3.1 Single-InputSingle-OutputChannel 78
5.3.2 Single-InputMulti-OutputChannel 79
5.3.3 Multi-InputMulti-OutputChannel 80
5.3.4 ChannelMatrixStructure 81
5.4 OFDMReceiverCategorization 82
5.4.1 ICI-IgnorantReceiver 82
5.4.2 ICI-AwareReceiver 83
5.4.3 Block-by-BlockProcessing 85
5.4.4 Block-to-BlockProcessing 85
5.4.5 Discussion 85
5.5 ReceiverPerformanceBoundwithSimulatedChannels 85
5.5.1 SimulatingUnderwaterAcousticChannels 86
5.5.2 ICIEffectinTime-VaryingChannels 86
5.5.3 OutagePerformanceofSISOChannel 87
5.6 ExtensiontoCP-OFDM 88
5.6.1 ReceiverPreprocessing 88
5.6.2 Frequency-DomainInput–OutputRelationship 89
5.7 BibliographicalNotes 89
6 Detection,SynchronizationandDopplerScaleEstimation 91
6.1 Cross-CorrelationBasedMethods 92
6.1.1 Cross-CorrelationBasedDetection 92
6.1.2 Cross-CorrelationBasedSynchronizationandDopplerScale
Estimation 96
6.2 Detection,SynchronizationandDopplerScaleEstimationwithCP-OFDM 99
6.2.1 CP-OFDMPreamblewithSelf-Repetition 99
6.2.2 Self-CorrelationBasedDetection,SynchronizationandDopplerScale
Estimation 100
6.2.3 Implementation 101
6.3 SynchronizationandDopplerScaleEstimationforOneZP-OFDMBlock 103
6.3.1 Null-SubcarrierbasedBlindEstimation 103
6.3.2 Pilot-AidedEstimation 104
6.3.3 Decision-AidedEstimation 104
6.4 SimulationResultsforDopplerScaleEstimation 104
6.4.1 RMSEPerformancewithCP-OFDM 105
6.4.2 RMSEPerformancewithZP-OFDM 106
6.4.3 ComparisonofBlindMethodsofCP-andZP-OFDM 107
6.5 DesignExamplesinPracticalSystems 108
6.6 ResidualDopplerFrequencyShiftEstimation 110
6.6.1 SystemModelafterResampling 110