【答案】《无线通信原理(双语)》(南京邮电大学)章节期末中国大学慕课答案

Chapter1IntroductiontoWirelessCommunicationsIntroductiontoWirelessCommunications1.单选题：In2000,ITUapprovedthreestandardsofWCDMA,CDMA2000and___.

选项：

A、TD-CDMA

B、IS-95

C、GSM

D、TD-SCDMA

答案：【TD-SCDMA】2.单选题：Forawirelesscommunicationsystem,iftheinputpoweris8dBm,andtheoutputpoweris5dBm,thesystemattenuationis___.

选项：

A、3dBm

B、3dB

C、13dBm

D、13dB

答案：【3dB】3.单选题：Ifacarrierfrequencyf=60GHzisadoptedforawirelesscommunication,thewavelengthλofthecarrierwaveis___.

选项：

A、5mm

B、10mm

C、20mm

D、50mm

答案：【5mm】4.单选题：TheBluetoothsystemsbelongtothewirelessnetworkof___.

选项：

A、WMAN

B、WLAN

C、WPAN

D、WWAN

答案：【WPAN】5.单选题：TheShannoncapacitydeterminesthetheoreticallimitonchannelcapacityforagivenbandwidthandsignal-to-noiseratio.

选项：

A、正确

B、错误

答案：【正确】6.单选题：WIFIisawirelesslocalnetworkthatrunsoftheIEEE802.15standardsset.

选项：

A、正确

B、错误

答案：【错误】7.单选题：Frequencydivisionduplexingsystemusesdifferenttimeslotsfortheforwardandreversechannels.

选项：

A、正确

B、错误

答案：【错误】8.单选题：Mostcellphonesoperateinthefrequencyrangeof800to2,200KHz.

选项：

A、正确

B、错误

答案：【错误】IntroductiontoWirelessCommunications1.Whatarethedifferencesamongthesimplexing,half-duplexingandfull-duplexing?

答案：【主要考察概念的具体描述】2.PleasedescribetheTDDandFDD,andthedifferencesbetweenthem.

答案：【主要考察概念的具体描述】3.100W=?dBW=?dBm

答案：【主要考察单位的理解和转换计算】4.Whattypescanthewirelesscommunicationnetworksbedividedinto?Pleasetakeatleastoneapplicationforeachtypeofthem.

答案：【主要考察概念的具体描述】Chapter2TheCellularConcept:SystemDesignFundamentalsTheCellularConcept:SystemDesignFundamentals1.If20MHzoftotalspectrumisallocatedforaduplexwirelesscellularsystemandeachsimplexchannelhas25kHzRFbandwidth,find(a)thenumberofduplexchannels.(b)thetotalnumberofchannelspercellsite,ifN=4cellreuseisused.

答案：【每问3分，主要考察公式的使用。】2.ForaN=7systemwithaPr[Blocking]=1%averagecalllengthfortwominutes,findthetrafficcapacitylossduetotrunkingfor57channelswhengoingfromomnidirectionalantennasto60degreesectoredantennas.(Assumethatblockedcallsareclearedandtheaverageperusercallrateisλ=1perhour.)

答案：【主要考察公式使用】3.Acertainareaiscoveredbyacellularradiosystemwith84cellsandaclustersizeN.300voicechannelsareavailableforthesystem.Usersareuniformlydistributedovertheareacoveredbythecellularsystem,andtheofferedtrafficperuseris0.04Erlang.AssumethatblockedcallsareclearedandthedesignatedblockingprobabilityisPb=1%(a)DeterminethemaximumcarriedtrafficpercellifclustersizeN=4isused.(b)Determinethemaximumnumberofusersthatcanbeservedbythesystemforablockingprobabilityof1%andclustersizeN=4.

答案：【每问4分，其中每种情况占10分。】TheCellularConcept:SystemDesignFundamentals1.单选题：IntheN-Cellreusepattern,thefrequencyreusefactoris1/N.

选项：

A、正确

B、错误

答案：【正确】2.单选题：Inadynamicchannelassignmentstrategy,eachcellisallocatedapredeterminedsetofchannels.

选项：

A、正确

B、错误

答案：【错误】3.单选题：Foraproperhandoffsituation,thehandoverthresholdshouldbesetslightlyweakerthanMinimumusablesignallevel

选项：

A、正确

B、错误

答案：【错误】4.单选题：InanN-cellreusepattern,Ncanchooseanypositivenumber.

选项：

A、正确

B、错误

答案：【错误】5.单选题：Inthecellularnetworks,thecoverageareaofeachbasestationisnamedascell.

选项：

A、正确

B、错误

答案：【正确】6.单选题：Sectoringhasthecapabilityofdecreasingtheco-channelinterferenceandthusincreasingsystemperformance.

选项：

A、正确

B、错误

答案：【正确】7.单选题：Asmallvalueoftheco-channelreuseratioprovideslargercapacity.

选项：

A、正确

B、错误

答案：【正确】8.单选题：Cellularradiosystemsrelyontrunkingtoaccommodatealargenumberofusersinalimitedradiospectrum.

选项：

A、正确

B、错误

答案：【正确】9.单选题：Aradiochannelthatisoccupiedfor20minutesduringanhourcarriers20Erlangsoftraffic.

选项：

A、正确

B、错误

答案：【错误】10.单选题：Cellsplittingisusedinhighdensitysubscriberareastodecreasesystemcapacity.

选项：

A、正确

B、错误

答案：【错误】Chapter3MobileRadioPropagation:Large-ScalePathLossMobileRadioPropagation:Large-ScalePathLoss1.IfPt=10W,Gt=0dB,andfc=900MHz,findPrinWattsatafreespacedistanceof1km.

答案：【主要考察公式使用】2.Assumethatlocalaveragesignalstrengthfieldmeasurementsaremadeinsideabuilding,andpostprocessingrevealedthatthemeasureddatafitadistant-dependentmeanpowerlawmodelhavingalog-normaldistributionaboutthemean.AssumethemeanpowerlawwasfoundtobePr(d)∝.Ifasignalof1mWwasreceivedat=1mfromthetransmitter,andatadistanceof10m,10%ofthemeasurementswerestrongerthan-25dBm,definethestandarddeviationσ,forthepasslossmodelatd=10m.

答案：【主要考察公式使用】3.Fourreceivedpowermeasurementsweretakenatdistancesof100m,200m,1km,and2kmfromatransmitter.Themeasuredvaluesatthreedistancesare-0dBm,-25dBm,-35dBm,and-38dBm,respectively.Itisassumedthatthepathlossforthesemeasurementsfollowsthelog-normalshadowingmodelwith=100m.(a)Findtheminimummeansquareerror(MMSE)estimateforthepathlossexponentn.(b)Calculatethestandarddeviationofshadowingaboutthemeanvalue.(c)Estimatethereceivedpoweratd=2kmusingtheresultingmodel.(d)Predictthelikelihoodthatthereceivedsignallevelat2kmwillbegreaterthan-35dBm.ExpressyouranswerasaQ-function.

答案：【每问2分，主要考察公式使用。】MobileRadioPropagation:Large-ScalePathLoss1.单选题：TheQ-functionisdeterminedbythefactorsexceptthe___ofthereceivedsignal.

选项：

A、thresholdlevel

B、averagepower

C、coveragearea

D、standarddeviation

答案：【coveragearea】2.单选题：Thegrowthrateofthepathlossinfreespaceis___.

选项：

A、1dB/decade

B、10dB/decade

C、20dB/decade

D、100dB/decade

答案：【20dB/decade】3.单选题：___occurswhenapropagatingwaveimpingesuponanobjectwhichhasverylargedimensionswhencomparedtothewavelengthofthewave.

选项：

A、Reflection

B、Diffraction

C、Scattering

D、Reflectionordiffraction

答案：【Reflection】4.单选题：Theeffectiveradiatedpowerdenotesthemaximumradiatedpowerascomparedtothe___.

选项：

A、isotropicantenna

B、monopoleantenna

C、half-wavedipoleantenna

D、parabolicantenna

答案：【half-wavedipoleantenna】5.单选题：Theclose-inreferencedistance,thepathlossexponentandthestandarddeviationstatisticallydescribethepathlossmodelconsideringrandomshadowingeffects.

选项：

A、正确

B、错误

答案：【正确】6.单选题：Thepathlossrepresentssignalgainasapositivedifferencebetweentheeffectivetransmittedpowerandthereceivedpower.

选项：

A、正确

B、错误

答案：【错误】7.单选题：Whenthemediumconsistsofalargenumberofobjectswithdimensionsthataresmallcomparedtothewavelength,scatteringwavecanbeobserved.

选项：

A、正确

B、错误

答案：【正确】8.单选题：Infreespace,thereceivedpowerisproportionaltothecarrierwavelength.

选项：

A、正确

B、错误

答案：【正确】Chapter4Small-ScaleFadingandMultipath,andIntroductionofMIMOTechnologiesSmall-ScaleFadingandMultipath,andIntroductionofMIMOTechnologies1.单选题：SmallScaleFadingisdividedintotwomain,i.e.,multipathdelayspreadandfrequencyspread.

选项：

A、正确

B、错误

答案：【错误】2.单选题：MIMOstandsfor‘MultipleInput,MultipleOutput’,andisaformofradioantennathatincreasesefficiencybyincreasingthenumberoftransmittersandreceivers.

选项：

A、正确

B、错误

答案：【正确】3.单选题：MIMOcapacityisindependentonpropagationchannel.

选项：

A、正确

B、错误

答案：【错误】4.单选题：ForabadMIMOchannels,spatialcorrelationishighandthecapacityislow.

选项：

A、正确

B、错误

答案：【正确】5.单选题：Whatisfrequencyflatfading?Atypeofsmallscalefadingwherefrequencysignalcomponentsexperiencedifferentmagnitudesoffading.

选项：

A、正确

B、错误

答案：【错误】6.单选题：Iftheattenuationandpathdelayofacomplexchannelresponsevarywithfrequency,thechanneliscalledatime-variantcomplexchannel.

选项：

A、正确

B、错误

答案：【错误】7.单选题：Forsimulatingafrequencyselectivechannel,discrete-timeTDLfiltersismandatorytohaveN=1whileNisthenumbertapsofthefilter.

选项：

A、正确

B、错误

答案：【错误】8.单选题：TherearemanydiversitymethodstorealizeIndependentfadingpaths,suchasSpaceDiversity,PolarizationDiversity,Frequencydiversityandtimediversity.

选项：

A、正确

B、错误

答案：【正确】9.单选题：Fadingcanbeclassifiedintosmallscalefadingandlargescalefading.

选项：

A、正确

B、错误

答案：【正确】10.单选题：Small-scalefadesarecharacterizedbydeepandslowamplitudefluctuationswhichoccurasthemobilemovesoverdistancesofjustafewwavelengths.

选项：

A、正确

B、错误

答案：【错误】Small-ScaleFadingandMultipath,andIntroductionofMIMOTechnologies1.Thetermchannelreferstothemediumbetweenthetransmittingantennaandthereceivingantennaandthemodelofthemediumiscalledchannelmodel.Thecharacteristicsofwirelesssignalchangesasittravelsfromthetransmitter(Tx)tothereceiver(Rx).ApartfromthedistancebetweenTxandRx,whatdothesecharacteristicsdependupon?

答案：【主要考察概念的理解】2.Theobjectslocatedaroundthepathofthewirelesssignalreflectthesignal，someofwhicharealsoreceivedatthereceiver.Sinceeachofthesereflectedsignalstakesadifferentpath,1)Determineiftheamplitudeandphaseofeachsignalarethesame;2)Howdoesthereceivedpowerchangewhentwocomplexsignalswithaphasedifferenceof180degreesareadded?andgiveanexample.

答案：【主要考察概念的理解】3.Dopplershiftisthefrequencyshiftofthesignalduetotherelativemotionbetweenthetransmitterandreceiver.DescribewhatDopplershiftiscalculatedbasedon.

答案：【主要考察概念的理解】4.Traditionalmethodsformodelingwirelesschannels,suchasPowerDelayProfileandDopplerspectrumcanaccuratelyrepresentthemultipatheffectsisasingle-input,single-output(SISO)system.However,theydonottypicallyincludethespatialcharacteristicsthatmayintroducecorrelationbetweenthechannelsofaMIMOsystem.Thesespatialeffectsinclude:thepowerazimuthspectrum,antennapositionandpolarization.Describewhatthepowerazimuthspectrumcharacterizes?

答案：【Thepowerazimuthspectrumcharacterizestheanglespreadassociatedwithanglesthatmaybedifferentforthesignalpathsconnectingtransmit/receiveantennapairs.】Chapter5MultipleAccessTechniquesforWirelessCommunicationsMultipleAccessTechniquesforWirelessCommunications1.单选题：CDMAusesthepowercontroltocombatthe.

选项：

A、self-jamming

B、near-farproblem

C、multi-userinterference

D、noiseinterference

答案：【near-farproblem】2.单选题：Whichsystemneedstheequalization?

选项：

A、OFDMA

B、FDMA

C、CDMA

D、TDMA

答案：【TDMA】3.多选题：WhichisthefeatureofslottedAloha?

选项：

A、Timeisdividedintoequaltimeslots.

B、Transmitonlyatthebeginningofatimeslot.

C、Avoidpartialcollisions.

D、Increasedelay,andrequiresynchronization.

答案：【Timeisdividedintoequaltimeslots.;Transmitonlyatthebeginningofatimeslot.;Avoidpartialcollisions.;Increasedelay,andrequiresynchronization.】4.多选题：WhicharefeaturesoftheCDMAsystem?

选项：

A、Softhandoff

B、near-farproblem

C、self-jammingandsoftcapacitylimit

D、RAKEreceiver

答案：【Softhandoff;near-farproblem;self-jammingandsoftcapacitylimit;RAKEreceiver】5.多选题：_____and____canimprovethecapacityofCDMAsystem.

选项：

A、AntennaSectorization

B、Cellsplitting

C、Voiceactivity

D、Coveragezoom

答案：【AntennaSectorization;Voiceactivity】6.单选题：Spreadspectrumlowersthesignalleverandreducesthebandwidthofchannel.

选项：

A、正确

B、错误

答案：【错误】7.单选题：ThevulnerableperiodinpureAlohaistwopackets,andthevulnerableperiodinslottedAlohaisapacket.

选项：

A、正确

B、错误

答案：【正确】8.单选题：ThereareTDMA/TDDandTDMA/FDD.

选项：

A、正确

B、错误

答案：【正确】9.单选题：CDMAissuperiortoTDMAandFDMA.

选项：

A、正确

B、错误

答案：【错误】10.单选题：ThecapacityofFDMAandTDMAsystemisinterferencelimited,whilethecapacityofCDMAsystemisbandwidthlimited.

选项：

A、正确

B、错误

答案：【错误】Chapter6IntroductionofNewCellularCommunicationTechnologyIntroductionofNewCellularCommunicationTechnology1.单选题：OFDMAisthehybirdofFDMAand.

选项：

A、CDMA

B、TDMA

C、FHMA

D、CSMA

答案：【TDMA】2.单选题：IntheOFDMA,eachsub-bandhas______sub-carriers.

选项：

A、12

B、10

C、8

D、14

答案：【12】3.单选题：5GdenotestheproposednextmajorphaseofmobiletelecommunicationstandardsbeyondthecurrentLTE-Advancedstandards.Theend-to-endlatencyrequirementin5Gsystemis.

选项：

A、0.01ms

B、0.1ms

C、1ms

D、10ms

答案：【1ms】4.单选题：mMTCof5Gdenotesmassivemachinetypecommunications.

选项：

A、正确

B、错误

答案：【正确】5.单选题：5GBandshavebeenbroadlydividedintotwocategories:sub-6GHz(FR1)andvisiblelight(FR2).

选项：

A、正确

B、错误

答案：【错误】IntroductionofNewCellularCommunicationTechnology1.WhatisLTEandLTE-A?PleasedescribetheLTEnetworkarchitecture.

答案：【主要考察概念的具体表达】2.Whatarethethreeapplicationscenariosof5G?

答案：【主要考察概念的具体表达】PrinciplesofWirelessCommunicationsPrinciplesofWirelessCommunications1.单选题：4Goffersfasteraccesstodatausingmobilephones,because4Gisdesignedfor_____.

选项：

A、voicetransmission

B、datatransmission

答案：【datatransmission】2.单选题：OFDMAisthehybirdofFDMAand_____.

选项：

A、CDMA

B、SSMA

C、TDMA

D、FHMA

答案：【TDMA】3.单选题：IntheOFDMA,eachsub-bandhas_____sub-carriers.

选项：

A、8

B、10

C、14

D、12

答案：【12】4.单选题：Fadingmodels:fadingtypesinwirelesscommunicationareimplementedinvariousmodelsordistributionswhichincludeRayleigh,_______,etc.

选项：

A、Gaussian

B、Rician

答案：【Rician】5.单选题：Spreadspectrumlowersthesignalleveland______thebandwidthofchannel.

选项：

A、reduces

B、improves

答案：【improves】6.单选题：SSMAcanconfrontthenarrowbandwidthinterferenceandthe_______.

选项：

A、co-frequencyinterference

B、multi-userinterference

答案：【multi-userinterference】7.单选题：CDMAusesthepowercontroltocombatthe_____.

选项：

A、self-jamming

B、near-farproblem

答案：【near-farproblem】8.单选题：CSMAismore_____thanAlohaprotocol.

选项：

A、efficient

B、inefficient

答案：【efficient】9.单选题：Infrequencyselectivechannels,theoutputofthechannelwillbethe_____oftheinputandthechannelresponse.However,infrequencyflatchannel,theeffectofthechannelismultiplicative

选项：

A、multiplication

B、convolution

答案：【convolution】10.单选题：InAWGNchannel,xistransmittedsignalandniscomplexGaussianrandomvariable,thenthereceivesignalyis______.

选项：

A、x+n

B、x*n

答案：【x+n】11.单选题：DelayspreadinfadingchannelsleadstoISIanderrorratesandequalization,spreadspectrum,_________maybeusedtomitigatetheeffects.

选项：

A、Channelcoding

B、OFDM

答案：【OFDM】12.单选题：_______standsfor‘MultipleInput,MultipleOutput’,andisaformofradioantennathatincreasesefficiencybyincreasingthenumberoftransmittersandreceivers.

选项：

A、MIMO

B、Multipleaccess

答案：【MIMO】13.单选题：Small-scalefadesoccurasthemobilemovesoverdistancesofjust_____wavelengths.

选项：

A、thousandsof

B、afew

答案：【afew】14.单选题：DopplershiftisalsoknownastheDopplereffectischaracterizedasachangeinwavelengthorwavefrequencywithrespecttotheobserverwhois______relativetothewavesource.

选项：

A、motion

B、instatic

答案：【motion】15.单选题：WhatisfrequencyselectiveFading?Atypeofsmallscalefadingwherefrequencysignalcomponentsexperiencedifferent______offading.

选项：

A、frequencies

B、magnitudes

答案：【magnitudes】16.单选题：FrequencyselectiveFadingiscausedby________wherethereceivedsignalconsistsofmultipledelayedandattenuatedversionsofthetransmittedsignal.

选项：

A、thecomplexpathattenuation

B、InterSymbolInterference

答案：【InterSymbolInterference】17.单选题：In____cell,basestationsatthecentreofeachcellwithomnidirectionalantennas.

选项：

A、centre-excited

B、edge-excited

答案：【centre-excited】18.单选题：Whenamobilemovesintoadifferentcellwhileaconversationisinprocess,a___isrequiredincellularradiosystem.

选项：

A、transferring

B、handover

C、trunking

答案：【handover】19.单选题：Forthe_____handoff,connectingtothenewcellisbeforedisconnectingfrompreviouscell.

选项：

A、soft

B、hard

答案：【soft】20.单选题：Theinterferencebetweenthesignalsfromthecellsusingthesamechannelsisnamedas___.

选项：

A、co-channelinterference

B、inter-modulationinterference

答案：【co-channelinterference】21.单选题：ThevalueofanantennagainindBdis___thatindBi.

选项：

A、>

B、<

C、=

D、≥

答案：【＜】22.单选题：Thefree-spacepathlossisproportionaltothe___andthepropagationdistance.

选项：

A、antennagain

B、carrierwavelength

C、antennaheight

D、carrierfrequency

答案：【carrierfrequency】23.单选题：Theaveragepathlossincreasesexponentiallywith___.

选项：

A、obstacle

B、distance

C、frequency

D、wavelength

答案：【distance】24.单选题：Inthecellularnetworks,many___powertransmittersareusedtoprovidecoveragetoonlyasmallportionoftheservicearea.

选项：

A、high

B、low

答案：【low】25.单选题：Ifeachuseraveragestwocallsperhourwithanaveragecalldurationofthreeminutes,thetrafficintensityperuseris____.

选项：

A、0.1

B、6

C、0.5

D、30

答案：【0.1】26.单选题：Bydecreasingthecellradiusandkeepingtheco-channelreuseratiounchanged,______increasesthenumberofchannelsperunitarea.

选项：

A、cellsplitting

B、sectoring

答案：【cellsplitting】27.单选题：Sectoring______thetrunkingefficiencywhileimprovingtheS/Iforeachuserinthesystem.

选项：

A、decreases

B、increases

答案：【decreases】28.单选题：Therearetwoduplexingtechnologies,thatisFrequencydivisionduplexingand_____.

选项：

A、Codedivisionduplexing

B、Timedivisionduplexing

答案：【Timedivisionduplexing】29.单选题：By___theratioofD/R,thespatialseparationbetweenco-channelcellsrelativetothecoveragedistanceofacellisincreased.

选项：

A、increasing

B、decreasing

答案：【increasing】30.单选题：Cellularradiosystemsrelyon___toaccommodatealargenumberofusersinalimitedradiospectrum.

选项：

A、handoff

B、trunking

答案：【trunking】31.单选题：Aradiochannelthatisoccupiedfor20minutesduringanhourcarriers_____Erlangsoftraffic.

选项：

A、1/3

B、20

C、1

D、3

答案：【1/3】32.单选题：Thegradeofserviceisusedtomeasuretheabilityofausertoaccessatrunkedsystem,whichcanbecomputedby_____.

选项：

A、Prob.[delay

B、Prob.[delay>T]

答案：【Prob.[delay】33.单选题：Ifacarrierfrequencyf=60GHzisadoptedforawirelesscommunication,thewavelengthλofthecarrierwaveis___.

选项：

A、5mm

B、10mm

C、20mm

D、50mm

答案：【5mm】34.单选题：Themobilecellularsystemsbelongtothewirelessnetworkof___.

选项：

A、WMAN

B、WLAN

C、WPAN

D、WWAN

答案：【WWAN】35.单选题：Thebroadcastingsystemisakindof___.

选项：

A、Simplexsystem

B、Half-duplexsystem

C、Full-duplexsystem

D、Timedivisionduplexsystem

答案：【Simplexsystem】36.单选题：10W=___dBm

选项：

A、10000

B、0.1

C、40

D、30

答案：【40】37.单选题：MIMOantennascansendandreceivesignalsoverthesamechannel,whichincreases______withoutsacrificingspectrum.

选项：

A、SNR

B、capacity

答案：【capacity】38.单选题：5GOverallsystemarchitectureconsistsof_____,CN(CoreNetwork)comprisingEPC(4GEvolvedPacketCore)and5GC(5GCN).

选项：

A、RAN

B、WLAN

答案：【RAN】39.单选题：Accordingtothe5Gand6GroadmappredictionwhichillustratesChina's6GPromotionGroup,3GPP's6Gstandardwork,etc.theusageperiodof5Gis2020-_______.

选项：

A、2020

B、2040

C、2025

D、2030

答案：【2030】40.单选题：mMTCof5Gdenotesmassive______typecommunications

选项：

A、thing

B、multiple

C、model

D、machine

答案：【machine】41.单选题：Azero-meancomplexsignalthathasanidenticalGaussiandistributiononboththein-phaseandquadraturecomponentswillhaveaphasethatisRayleighdistributed.

选项：

A、正确

B、错误

答案：【错误】42.单选题：WidebandFadingreferstoradiochannelswhoseoperationalbandwidthmaysignificantlyexceedthecoherencetimeofthechannel.Thechannelsarecalledselectivefadingorfrequencyselectivefadingchannelsbecausedifferentpartsofthesignalwillbeaffectedbythedifferentfrequencies.

选项：

A、正确

B、错误

答案：【错误】43.单选题：Thecentrallimittheorem(CLT)statesthatthesumofalargenumberofindependentrandomvariableswillhaveadistributionthattendstowardaGaussiandistributionregardlessofthedistributionoftheindividualprocesses.

选项：

A、正确

B、错误

答案：【正确】44.单选题：FrequencyselectiveFadingcorrespondstothecasewherethesignalbandwidthisremarkablylargerthanthechannelcoherencebandwidth(BW).

选项：

A、正确

B、错误

答案：【正确】45.单选题：LTE-Ahasradioaccessnetworkandcorenetwork,adoptsSC-FDMAforthedownlinkandOFDMAfortheuplink.

选项：

A、正确

B、错误

答案：【错误】46.单选题：DifferentPNsequencesareuesdforthespreadinganddispreadingoperationsforauserinthethespectrumspreadingcommunications.

选项：

A、正确

B、错误

答案：【错误】47.单选题：ThecapacityoftheTDMAsystemissoftcapacity.

选项：

A、正确

B、错误

答案：【错误】48.单选题：Fadingsignalsoccurduetoreflectionsfromgroundandsurroundingbuildingsaswellasscatteredsignalsfromtrees,peopleandtowerspresentinthelargearea.

选项：

A、正确

B、错误

答案：【正确】49.单选题：GoalofuRLLC:millisecondlevelslatencyrequirementandultrareliabilityservicescenario:InternetofVehicles.

选项：

A、正确

B、错误

答案：【正确】50.单选题：Duetothecoveragecharacteristicsofthe5Gfrequencybands,high-bandsaresuitableforbothdenseurbanareasandnationalwidecoverage.

选项：

A、正确

B、错误

答案：【错误】51.单选题：Thesub-6GHzbandmeansth