太赫兹通信白皮书（英文）

THzCommunication

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Contents

ListofFigures 3

ListofTables 4

1.IntroductiontoTerahertzCommunication 5

1.1THzChannelCharacteristicsandInfluences 5

1.2ResearchonTHzCommunicationinChinaandOverseas 5

1.3ProgressinStandardDevelopment 7

1.4THzSpectrumUtilization 8

1.5Government-FundedResearchProgramsonTHzCommunication 9

2.TypicalTHzApplications 13

2.1Indoor/OutdoorWirelessTransmission

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3

2.2THzCommunicationattheMicro-nanoScale 16

2.3Inter-SatelliteCommunicationinAir-and-SpaceIntegration 17

2.4JointCommunicationandSensingbasedontheTHzBand 17

3.CoreDevicesofTHzCommunication 20

3.1THzSignalSource 20

3.2THzRelatedKeyDevices 22

3.2.1THzPowerdevices 22

3.2.2THzFrequencyConverter 23

3.2.3General-purposeTHzComponentsandSubsystems 24

3.3THzAntenna 25

3.4THzRFSystemIntegration 26

4.ThoughtsonTHzChannelMeasurementandModeling 28

4.1NewThoughtsonTHzChannelMeasurementTechnology 28

4.1.1Ultra-broadbandChannelMeasurement 28

4.1.2THz/Sub-THzBandChannelMeasurement 29

4.1.3OvercomingHighPathLoss 29

4.1.4AngleDomainChannelParametersMeasurement 30

4.2THzChannelEstimationandChannelModeling 31

4.2.1ChannelParametersEstimation 31

4.2.2ChannelModeling 32

5.KeyTechnologiesandChallengesofTHzCommunication 34

5.1NewOTATechnologies 34

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5.1.1ModulationandCodingTechnology 34

5.1.2WaveformDesign 35

WaveformDesignStrategy 36

THz(New)WaveformDesign 38

PhysicalLayerNumerologyDesign 41

5.1.3Synchronization 45

5.2MassiveMIMOTechnology 45

5.2.1PhasedArrayAntennaArchitecture 45

5.2.2BeamTracking 48

5.2.3SpatialMultiplexing 49

5.3THz-RelatedNetworkLayerTechnology 50

5.4THzandIntelligentReflectingSurface(IRS) 51

5.5JointCommunicationandRadio/RadarSensing 52

6.ChallengestoDesignandTestingofTHzCommunicationPrototypeSystems 57

6.1ChallengestotheDesignofTHzHardwareSystems 57

6.2DevelopmentandTestingofTHzPrototypeSystems 61

7.6GDevelopmentPlanningandSuggestionsbasedontheTHzBand

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8

8.References 70

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ListofFigures

Figure1:ChannelAttenuationCausedbyDifferentEnvironmentalFactorsinDifferent

FrequencyBands[1]

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Figure2:THzPublicationsinRecentYears[1] 7

Figure3:TargetApplicationScenariosofIEEE802.15.3d 8

Figure4:High-speedAccessApplication(Source:Internet) 13

Figure5:FWAOperatingMode 14

Figure6:ApplicationofBackhaulLink 14

Figure7:ApplicationofSecureCommunication(Source:Internet) 15

Figure8:High-speedIn-VehicleCommunication 16

Figure9:THz-basedMicro-nanoCommunication 16

Figure10:THz-basedInter-SatelliteCommunication(Source:Internet) 17

Figure11:(a)Specularreflectionofobjectsinthemicrowavefrequencyband;(b)Diffuse

reflectionofthesameobjectsinthevisibleandinfraredbands;(c)Specularreflection

anddiffusereflectionintheTHzband[15]

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9

Figure12:TechnologyRoutesofTHzSignalSource[16] 21

Figure13:The50to250GHzBroadbandInPHBTPowerAmplifierMMICSeriesReleased

byTeledyne

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3

Figure14:ADiodeDesign 24

Figure15:PA’sSaturatedOutputPowervsCarrierFrequency[31] 37

Figure16:SymbolErrorRate(SER)ComparisonBetweenOFDMandSC-FDE 39

Figure17:Sub-Carrier(1024),DataBlockSize(256),OversamplingFactor(4).PAPR

ComparisonBetweenDFT-s-OFDMandOFDM

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0

Figure18:PAPRComparisonBetweenOFDM,DFT-s-OFDM,UW-DFT-s-OFDM,SC-FDE,

OTFSandDFT-s-OTFS

4

1

Figure19:BERComparisonBetweenOFDM,DFT-s-OFDM,UW-DFT-s-OFDM,SC-FDE,

OTFSandDFT-s-OTFSinCaseofDopplerShift

4

1

Figure20:"Numerology"DefinedinCommunicationSystem[1] 42

Figure21:Link-LevelPerformanceWhenPhaseNoiseExists:a)OFDMandb)SC-FDMA

useRel-15compliantPTRS;c)OFDMandd)SC-FDMAuseenhancedPTRSstructures,

90GHzcarrier,rank-2......................................................................................................43

Figure22:MajorDesignPrinciples/Methodsof"Numerology"inTraditionalCommunication

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System[34] 45

Figure23:Fully-ConnectedArchitectureofHybridBeamforming 47

Figure24:Sub-arrayArchitectureofHybridBeamforming 47

Figure25:HierarchicalGeneralizedArchitectureofHybridBeamforming 48

Figure26:JCASApplicationonWiFiand6G 53

Figure27:CSIMeasurementErrorSourceswithTypicalWiFi2.4GHzReceiverwithDirect

DownConversionArchitecture[44]

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5

Figure28:PhaseNoiseofSub-THzUp-ConverterDesign 58

Figure29:PhaseNoiseSimulationResult 59

Figure30:Band-PassFilterandPowerAmplifierAddedtotheSub-THzUp-Converter

Design

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0

Figure31:SimulationResultwiththeBand-PassFilterandPowerAmplifierAdded 60

ListofTables

Table1:OverviewofGlobalTHzStudies 6

Table2:ListofTHzCommunicationSpectrumsIdentifiedbyWRC-19[11] 9

Table3:ListofGovernment-FundedTHzPrograms 10

Table4:CharacteristicsofTypicalSemiconductorMaterials 23

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1.IntroductiontoTerahertzCommunication

Thischapterbrieflyintroducesthecharacteristicsandthestatusquoofterahertz(THz)communication,includingTHzchannelcharacteristics,researchstatusathomeandabroad,IEEE’sprogressindevelopingTHzstandards,frequencyspectruminvolved,andsomegovernment-fundedresearchprogramsonTHzcommunication.

1.1THzChannelCharacteristicsandInfluences

ToenableefficientwirelesscommunicationintheTHzband,investigationsofchannelcharacteristicsinthisfrequencyrangeareneeded.TheTHzbandfeaturestheuniquereflectionandscatteringattenuationofhighfrequencybands,aswellasthespatialdistributionsofspecularreflectionandnon-specularreflectionalongthepropagationpaths.HighlydirectionalbeamsareusuallyusedtocombatthehighpathlossintheTHzband,howevertheyresultinbeammisalignmentinthefrequencydomainevenforservingmobileusersinasmallareaonly.ThemainpropagationcharacteristicsofTHzwavesareshowninFigure1,whichmustbeconsideredinTHzchannelmodeling.ExistingchannelmodelscannotbeapplicabletotheTHzband,becausetheycannotcaptureandemulatedifferentphenomena,includingattenuationandnoiseduetomolecularabsorption,scatteringcausedbyparticleswithanequivalentwavelengthofTHz,andscintillationresultedfromTHzradiation.SuchpropagationcharacteristicsaskforanewchannelmodeltoeffectivelycharacterizechannelsintheTHzband.Inparticular,inthelowerTHzspectrum,suchasthefrequencybandbelow500GHz,channelcharacteristicsneedtobefurtherexploredandanalyzed.

Figure1:ChannelAttenuationCausedbyDifferentEnvironmentalFactorsinDifferentFrequencyBands[1]

1.2ResearchonTHzCommunicationinChinaandOverseas

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ThetermTerahertzwasfirstproposedbytheInternationalMicrowaveSymposiuminthe1970stodescribeinterferometers’frequencyspectrum,diodedetectors’coverage,andwater-laserresonanceamongothers[1][2][3][4].Inaround2000,THzwasreferredtoassub-millimeterwavesinthefrequencyrangefrom100GHzto10THz.However,therewasnotacleardefinitionontheboundarybetweensub-millimeterwaveandfar-infrared.TheconceptofusingTHzforultra-broadbandcommunicationbasedonnon-line-of-sight(NLOS)signalcomponentswasfirstproposedinarticle[5],whichwasconsideredasaviablesolutionforextremelyhighdataratetransmission.Sincethen,theapplicationofTHztechnologyincommunicationhasbeenafocusinacademicstudies.TherelevantstudieshavebeencapturedinthestatisticsofIEEEandWebofSciencepublicationsinrecentyears(asshowninFigure2).Throughjointefforts,researchteamsaroundtheworldaredevelopingnewdesigns,newmaterialsandnewprocesses,highlightingthehugeprospectoftheTHztechnology.Table1isanoverviewofglobalstudiesinthefieldofTHz(partiallysourcedfrom[1]).

Table1:OverviewofGlobalTHzStudies

Team/Lab

Region

ResearchInterests

MittlemanLab,BrownUniversity

United

States

THzphysicallayer,THzspectroscopy,THzdetection

BroadbandWirelessNetworkingLab,GeorgiaInstituteofTechnology

United

States

THzphysicallayeraccesslayer,THzmicro-nanocommunication,THzdevices

NaNoNetworkingCenter

Spain

THzmicro-nanocommunication

Ultra-broadband

Nano-CommunicationLaboratory,UniversityatBuffalo

United

States

THzphysicallayeraccesslayer,THzmicro-nanocommunication,THzdevices

TerahertzElectronicsLaboratory(UCLA)

United

States

THzsources,reconfigurablespectroscopy

detectors,spectrometers,

meta-film,imagingand

MITTerahertzIntegratedElectronicsGroup

United

States

Sensing,metrology,securityand

communicationintheTHzband

FraunhoferInstituteforAppliedSolidStatePhysicsIAF

Germany

THzphysicallayeraccesslayerandRFelectronics

TerahertzCommunications

Lab

Germany

Channelmeasurementandmodeling,THzreflectors

NTTCoretechnologylaboratoryGroup

Japan

THzintegrateddevicesandmodular

technology

TexasInstrumentKilby

Lab

United

States

Sub-THzultra-lowpowerCMOSsystems

TonouchiLab,OsakaUniversity

Japan

THznanoscience,THzbioscience,THzbiosensing,andindustrialapplications

THzElectronicsSystemsLab,KoreaUniversity

South

Korea

THzphysicallayeraccesslayerandRFelectronics

NanocommunicationsCenter,

TampereUniversityofTechnology

Finland

THzphysicallayerandmicro-nano

communication

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UniversityofElectronicScienceandTechnologyofChina

China

High-powerTHzsources,newTHzsources,THzquasi-opticaldevices,THzcommunication,THzactivemetasurface,keytechnologiesinthefrontpartofTHzimagingsystems,THzhigh-speeddirectcontroldevicesandapplications

CETCNo.13ResearchInstitute

China

THzmixers,frequencymultipliers,

amplifiers

Figure2:THzPublicationsinRecentYears[1]

1.3ProgressinStandardDevelopment

StandarddevelopmentforfuturewirelesscommunicationsystemsintheTHzbandwasinitiatedbytheIEEE802.15THzInterestGroupinearly2008.In2013,theIEEE802.15WPANTaskGroup3-D100Gbit/swireless(TG3d100G)[6]wasofficiallyestablishedtodevelop100Gbpswirelesscommunicationstandardsforthefrequencyrangefrom275GHzto325GHz.ThankstotheTG’sefforts,IEEE802.15.3d-2017,theworld'sfirstwirelesscommunicationstandard,wasapprovedonSeptember28,2017andreleasedonOctober12,2018[7].ThisstandardtargetsataseriesofTHzcommunicationapplicationscenarios,includingKioskdownload,intra-devicecommunication,wirelessbackhaulandfronthaul,andradiolinksindatacenters(asshowninFigure3).Relevantapplicationcases,performanceandsystemfunctionrequirementsaredefinedintheapplicationrequirementsdocumentofIEEE802.153d[8].

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Figure3:TargetApplicationScenariosofIEEE802.15.3d

ThestandardcoversthenewphysicallayertechnologyandtheMAClayertechnologythatsupport8channelswithabandwidthfrom2.16GHzto69.12GHz.Inaddition,itsupportssevenmodulationformats(BPSK,QuadraturePhaseShiftKeying(QPSK),8-PSK,16-QAM,64-QAMandOOK)andthreeencodingformats(RS(240,224),14/15-LDPCand11/14-LDPC).Thestandardalsosupportssingle-carriermodeandOOKmodeatthephysicallayer.

Thechannelmodelingdocument[9]summarizeschannelpropagationcharacteristicsoftargetscenarios,andspecificallyproposeschannelmodelsbasedondifferentapplicationscenarios.Asthenextstep,thestandardwilllookintotheinterferenceofTHzcommunicationonthefrequencybandsidentifiedbytheInternationalTelecommunicationUnion(ITU)andmakeitavailableforradioastronomy,satelliteearthexploration,andspaceresearchservicesamongotherapplications[10].Asisknowntoall,thepowerlossinTHzpropagationismainlyattributedtotheabsorptionofwatervapor.Therefore,animportantresearchareainthenextstepisdetailedanalysisofregionalpropagationcharacteristics.

ThewirelessTHzconnectivityspecifiedinIEEE802.15.3disonlyapplicabletofixedpoint-to-pointlinks.THz-basedapplicationsinWLANarestilltobeexploredfurther.Currentlyspeaking,IEEE802.15TAGTHzisalsoexploringnewsolutionsforthephysicallayerandthelinklayerinthesub-THzandTHzbandswithinthe10GHzto100GHzrange.TheideasandsolutionsproposedbyIEEE(802.15.3d)willcontributetotheimplementationofTHzcommunicationandsetafoundationfor6Gwirelesssystemsinthefuture.

1.4THzSpectrumUtilization

IntermsofTHzcommunicationspectrum,whileensuringsomepassiveservices,suchasradioastronomyandEarthExplorationSatelliteService(EESS),canbeprotectedfromharmfulinterference,radioregulationsallowtheuseofspectrumabove275GHz.The2015WorldRadiocommunicationConference(WRC)graduallyidentifiedthespectrumsforterrestrialmobileservicesandfixedservicesintherangefrom275GHzto450GHzwhileensuringnointerferencetopassiveservices,andthesespectrumswerediscussedundertheWRC2019agendaitem1.15.ThefrequencybandsidentifiedbytheWRC2019(275-296GHz,306-313GHz,318-333GHz

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and356-450GHz)willbeusedforimplementinglandmobileservicesandfixedservices,butintherangeof296-306GHz,313-318GHz,and333-356GHz,certainrestrictionsneedtobeintroduced.Addinguponthespectrumpreviouslyallocatedfrom252to275GHz,atotalof160GHzcanbeusedforTHzcommunicationintherangefrom275GHzto450GHzwithnospecificEESSprotectionrequirements..

Table2:ListofTHzCommunicationSpectrumsIdentifiedbyWRC-19[11]

FrequencyBand(GHz)

RulesforSpectrumUse

252-275

Prioritizelandmobileservicesandfixedservices

275-296

Forlandmobileservicesandfixedservices

NospecificEESSprotectionrequirements

306-313

318-333

356-450

296-306

Limiteduseforlandmobileservicesandfixedservices,withEESSprotectionrequirements

TheConfederationofEuropeanPostsandTelecommunications(CEPT)completedusagespecificationsforthe92to114.25GHz(Wband)andthe130to174.8GHz(Dband)in2018[12].Otherthanthat,therearesofarlimitedregulationsonusing90GHzandabovefrequenciesinEurope.Fixedwirelessservicesoperatinginthespectrumsdefinedabovefeaturethefollowing:1)Verylargeavailablebandwidththatallowslow-costdatatrafficintheareasofdiversifiedserviceproviders;2)Thedeploymentofradiolinksismorefeasiblethanthatofwiredconnections;3)Lowsignalinterferenceandlowinterceptionprobability,whichensuringhighsecurityofsignals.In2019,inordertoaddresstheETSIrequirementsforradiomeasurementapplicationsinthefrequencyrangefrom120GHzto260GHz,CEPTdevelopedstandardsforthecorrespondingspectrums.

Alsoin2019,theFederalCommunicationsCommission(FCC)decidedtoapplynewregulationstofrequencybandsabove95GHz,soastoacceleratetheapplicationofsub-THzandTHzbands[13].Thismeansthatexperimentallicensescanbeobtainedforthefrequencyrangefrom95GHzto3THz,aswellastheunlicensedspectrumat21.2GHz.

1.5Government-FundedResearchProgramsonTHzCommunication

TheTHzbandguaranteesalargethroughput,andcantheoreticallyexpandtheavailablefrequencyspectrumtoseveralTHzandachieveacapacityofTbps[10].BecauseofthehugepotentialofTHztechnology,extensiveresearchiscarryingout,alongwithnewdesigns,newmaterialsandnewmanufacturingtechnologiesintheTHzband.Governmentsandscientificinstitutesaroundtheworldwishtoopenanewhorizonfor6Gintermsofcommunicationanddevices,andarethereforeprovidingrobustsupportforthevariousTHzprograms.Table3liststhelatestTHzprogramsprojectsathomeandabroad(partiallysourcedfrom[1]).

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Table3:ListofGovernment-FundedTHzPrograms

Program

Fundedby

Commencement

Objectives

R&DProgramonExpandingRadioSpectrumResources

TheMinistryofInformationand

Communications

andtheMinistryofEducation,Culture,Sports,ScienceandTechnology,Japan

2008

Explorenewtechnologiestoincreasespectrumutilization,promotesharedspectrumuseandadoptionofhigherfrequencybands

WirelessLAN

Communication

TechnologyinTHz

band

SouthKorean

government/IITA

2008

ExploreTHzWLAN/PANcommunicationsystemsbasedonelectronicdevices

Roomtemperature

TheEUFramework

2010

Manufacturesolid-state

THzemissionand

Programmefor

transmittersanddetectors

detection

Research

operatingintheTHzband

semiconductor

nano-devices

(ROOTHzProgram)

TERAPAN:

FederalMinistryof

2013

DevelopanindoorTHz

Controllable

Educationand

adaptivewireless

Antenna-based

Research,Germany

communicationprototype

Ultra-HighDataRate

withadatarateof100Gbps

TransmissionSystem

fortheTHzBand

iBROW:Omni-present

Horizon2020ofEU

2015

Exploreinnovative

Ultra-Broadband

ultra-broadbandshort-range

Wireless

wirelesstransceiver

Communicationbased

technologywithalowcost

onTHzTransceiver

andhighefficiency

Technology

TERAPOD:

Horizon2020ofEU

2017

DemonstrateTHzradiolink

THz-based

communicationand

Ultra-Broadband

proof-of-concept

WirelessAccess

Network

ThoR:THzEnd-to-endWireless

Communication

SystemDeliveringHighDateRate

Horizon2020ofEUandtheNationalInstituteofInformationand

Communications

Technology(NICT),Japan

2018

Proposesolutionstosupportthedatabackhaulandfronthaulofthe300GHz

frequencyband

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ULTRAWAVE:

mmWaveTravelingWaveTube-based

Large-capacity

Wireless

Communicationinthe100GHzandabove

FrequencyBands

Horizon2020ofEU

2017

Achieve5Gcellularintensitybyemployingthe100GHz

andabovefrequencybandstodeveloplarge-capacity

backhaullink

TERRANOVA:THzWirelessTransmissionTechnologytoDelivertheQualityExperienceofOpticalNetworks

Horizon2020ofEU

2017

Provideareliableconnectionwithhighrateandalmostzerolatencytorealizetheevolutionfromopticalfibertowireless

EPIC:Next-generationofChannelEncodingforTbpsTransmission

Horizon2020ofEU

2017

ExplorenewFECencodingtechnologytoenableTbpswirelesstransmission

DREAM:D-bandWirelessSolutiontoAchieveaReconfigurableMeshNetworkbeyond100Gbps

Horizon2020ofEU

2017

ExploreawirelessbackhaulsolutionwithadatarateexcellingthecurrentV-bandandE-bandtoachievethedatarateofopticalfibersystems

WORTECS:WirelessOpticalandRadioTHzCommunications

Horizon2020ofEU

2017

DevelopawirelesstransmissiontechnologycapableofdeliveringTbpsrateinthefrequencybandabove90GHzthroughtheintegrationofphotonicandelectronictechnologies

TeraNova:IntegratedTestPlatformforTHz

Communication

NationalScience

Foundation(NSF)

2017

DevelopthefirstR&Dandtestplatformfortheultra-broadbandTHz

communicationnetwork

EAGER:ResearchandDevelopmentofTHzComponentsbasedonHigh-performance

OpticalPhonons

NationalScience

Foundation(NSF)

2017

SystematicallyexplorehowtoimplementinnovativeTHzsourcesindifferent

workingmodes

InnovativeTHzGeneratorsbasedon

MagneticMaterials

NationalScience

Foundation(NSF)

2017

ExploreinnovativeTHzgeneratorsbasedonthetheoryoftransformingTHzwavesthroughmagneticoscillation

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mmWaveandTHz

Wireless

Communication

Technology

Development

TheNational863

ProgramofChina

2010

Researchonthreeterahertzcommunicationarchitecturescoveringthefrequencyrangefrom0.1THzto7THz

THzWireless

Communication

Technologiesand

Systems

Amajor

program

specialofthe

2018

Inresponsetotheapplicationrequirementsofhigh-speedspacetransmissionandthenext-generationofmobilecommunication,exploreanoveralltechnicalsolutionforTHzhigh-speedcommunicationsystems;explorechannelmodelofTHzspatialandterrestrialcommunication;

explorehigh-speedandhigh-precisionTHzsignalcapturingandtrackingtechnology;explorehigh-speedbasebandsignalprocessingtechnologyfeaturinglowcomplexityandlowpowerconsumptionaswellastheICdesignmethod;exploreTHzhigh-speedcommunicationbasebandplatform;exploreTHzhigh-speedmodulationtechnologies,includingTHzdirectmodulation,THzmixedmodulation,andTHzphotoelectricmodulation;exploreRFunitsforTHzhigh-speedcommunication;integrateTHzcommunicationbaseband,RFandantennatodevelopanexperimentalTHzhigh-speedcommunicationsystem,andcompleteTHzhigh-speedcommunicationtesting

MinistryofScienceandTechnologyofChina

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2.TypicalTHzApplications

TheTHzbandcanprovidealargeamountofavailablebandwidthtomeettherequirementsofultra-high-speedwirelessconnectionandtheTbpsrateinthefuture.BecauseofthelargepathlossandenvironmentalimpactsintheTHzband,ithasalimitedcoverageandisthereforemoresuitableforhigh-speedcommunicationwithinasmallerrange.HowtoeffectivelyutilizethelargebandwidthoftheTHzbandwhileensuringreasonablecoverageisoneofthekeyproblemstoberesolvedinthestudyofTHzapplicationscenarios.Inconsiderationofthelargebandwidthandtheuniquechannelcharacteristics,regardlessofthechallengesahead,THzcommunicationcanstillfosterawiderangeofuniqueapplicationstoaddressthepotentialneedsofhumankindinthe6Gera,suchasground-basedindoorandoutdoorwirelessaccess,minimum-rangecommunication,air-and-spaceintegration,andjointcommunicationandsensingservices.

2.1Indoor/OutdoorWirelessTransmission

TakingoverallconsiderationoftheTHzchannelcharacteristicsandthecurrentITUallocationoftheTHzspectrum,theapplicationprospectsofthelow-frequencypartofTHzspectruminthe6Geraarediscussedinthebelow.Therefore,theTHzbandreferredtointhebelowismainlyfrom100GHzto500GHz,thatis,thesub-THzspectrum.

High-speedwirelessaccessisthemostprominentapplicationofwirelesscommunication.THzcommunicationcanbeusedin6Gcellularcellstoestablishahierarchicalcellularnetworkor

heterogeneousnetworkincombinationwiththelowfrequencybandsystems,providingultra-high-speeddatacommunicationwithinacoverageof10mto50m,andofferinglargecapacitytransmissionservicetohotspots.Apartfromhotspotcoverage,theTHzbandalsoneedstoaddresstherequirementsandchallengesofcontinuoushigh-speedoutdoorcoverage.Continuouscoverageisakeyrequirementofwirelesscommunicationapplications.TheapplicationoutlookoftheTHzbandinthisareaisanimportantindicatorwhenconsideringitasakey6Gcandidatetechnology.

Figure4:High-speedAccessApplication(Source:Internet)

FWA(fixwirelessaccess)isawirelessaccessoperatingmodethatprovidesfixedandmobile

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userswithseamlessconnectivitybetweenultra-high-speedwirednetworkandwirelessdevices.ItmeetsthetransmissionrequirementsofHDmultimediastreamingandUHDvideoconferencing,andaddressesthelastbitofchallengewhenextendingnetworkcoveragefromoutdoortoindoor.

Figure5:FWAOperatingMode

THzcansupportshort-rangecommunicationandeffectivelyminimizethenegativeeffectsduetohighpathattenuationandmolecularattenuationintheTHzband.Thetypicalapplicationscenariosincludeshort-rangehigh-speeddownload(suchasKIOSK).Suchapplicationsrequireterminalstobecapableoftransmittingathighdatarates.Thedistancebetweentheuserandtheterminalisusuallylessthan1m,soastofitintheshorttransmissionrangeandthepoint-to-point(P2P)networktopology.

THzcommunicationenablesseamlessinterconnectionbetweentheultra-high-speedwirednetworkandpersonalwirelessdevices.Bycoordinatingthewirelessandwiredlinktransmissionrates,itcansupportbandwidth-intensiveapplicationssuchasHDholographicvideoconferencing.ItcanbeusedtoestablishaTbpslinkamongadjacentdevices,suchastheultra-high-speeddatatransmissionbetweenpersonaldevices,greatlyimprovingthedatatransmissionrate.

TheTHzbandlaysasolidfoundationforthedevelopmentoflarge-capacitywirelessfronthaul/backhaullinks,andcanbeexpandedfurtherforthedeploymentofultra-densenetworksandcoordinatedmultipointtransmission.TakingthelargebandwidthofTHzintoconsideration,intheapplicationscenariosofbackhaulandfronthaullinks,large-scalehigh-gaindirectionalantennaarrayscanbeemployedatthetransmittingandreceivingendstoincreasethebeamforminggain,hencetoenablelong-rangetransmission.

Figure6:ApplicationofBackhaulLink

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Apartfromtheabove,THzcanalsobeusedforsecurecommunication.Themainapplicationsinvolvethefollowing:usingultra-broadbandsecurecommunicationlinksinmilitaryapplicationstodete