规划试题39题e.docx
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规划试题39题e
填空题
FillingintheFollowingBlanks.
1.传播模型分为统计型模型和决定型模型。
常用的模型有:
Okumura-Hata和COST-231。
Thepropagationmodelsareclassifiedintostatisticsmodelanddecisionmodel.ThecommonmodelsareOkumura-HataandCOST-231.
2.常用的抗干扰技术有:
跳频(FH)和不连续发射(DTX)等。
Thecommonanti-interferencetechnologiesareFrequencyHopping(FH)andDiscontinuousTransmission(DTX).
3.常用的分集技术主要包括:
空间分集,时间分集,频率分集和极化分集。
Thecommondiversitytechnologiesincludespacediversity,timediversity,frequencydiversityandpolarizationdiversity.
4.GSM中的跳频可分为基带跳频和射频跳频。
ThefrequencyhoppinginGSMcanbeclassifiedintobasebandfrequencyhoppingandradiofrequencyhopping.
5.通常的频率复用方式有:
普通复用,双重复用,同心圆复用和多重复用MRP。
Thecommonfrequencyreusemodesincludeordinaryreuse,doublereuse,concentriccirclereuseandMultipleReusePattern(MRP).
6.描述天线增益通常使用的两个单位是dBi和dBd。
转换关系为:
dBianddBdarethetwounitsthataretypicallyusedtodescribetheantennagain.Theirrelationshipis:
0dbd=2.15dbi
0dbd=2.15dbi
7.手机开机时进行小区选择的准则是C1,手机在空闲状态下进行小区重选的准则是C2。
Thecriterionforcellselectionis____C1____whenthemobilephoneisswitchedon,andthecriterionforcellreselectionis___C2_____whenthemobilephoneisinidlestatus.
8.双频网规划原则:
GSM900网络保证覆盖,DCS1800网络充分吸纳话务量
Principlesfordual-bandnetworkplanning:
TheGSM900networkguaranteesthecoverage,whiletheDCS1800networkfullyacceptsthetraffic.
9.GSM中的跳频序列主要由两个参数描述:
(HSN(跳频序列号))和(MAIO(移动配置索引偏移量))
ThefrequencyhoppingsequenceinGSMismainlydescribedbytwoparameters:
(HSN(HoppingSequenceNumber))and(MAIO(MobileAllocationIndexOffset)).
10.一般人体损耗设为(3dB)
Generally,thelossofhumanbodyissetto(3dB).
11.BISC由(NCC)和(BCC)组成,取值范围分别是(0-7)和(0-7)。
BISCconsistsof(NCC)and(BCC),whosevaluerangesarerespectively(0-7)and(0-7).
12.控制信道用于携带信令或同步数据,可分为广播信道,公共控制信道和专用控制信道。
Thecontrolchannelisusedtocarrythesignalingorsynchronizedata.Therearethreetypesofcontrolchannel:
broadcastchannel,commoncontrolchannelanddedicatedcontrolchannel.
13.逻辑信道分为业务信道和控制信道。
LogicalchannelscanbedividedintoTrafficChannelandControlChannel.
14.GSM采用跳频有两个原因,是因为它可起到频率分集和干扰源分集的作用。
TherearetwocausesforuseoffrequencyhoppinginGSM:
Itcanactasfrequencydiversityandinterferencesourcediversity.
15.同频干扰保护比:
C/I>9dB,一般在工程中加3dB余量。
邻频干扰保护比:
C/A>-9dB,一般在工程中加3dB余量。
Theco-frequencyinterferenceprotectionratioC/I>9dB.Usually3dBallowanceisreservedintheengineering.TheadjacentfrequencyinterferenceprotectionratioC/I>-9dB.3dBallowanceisreservedintheengineering.
16.实现多址的方法基本有三种:
频分多址FDMA,时分多址TDMA,码分多址CDMA。
Multipleaccesscanbeimplementedinthreeways:
FDMA(FrequencyDivisionMultipleAccess),TDMA(TimeDivisionMultipleAccess),CDMA(CodeDivisionMultipleAccess).
17.GSM网的网络质量测试主要包括:
CQT测试和DT测试。
ThenetworkqualitytestsfortheGSMnetworkincludeCQTandDT.
18.GSM系统由一系列功能单元组成,分为MS(移动台),NSS(网络子系统),BSS(基站子系统),OSS(操作维护子系统)等组成。
TheGSMsystemconsistsofaseriesoffunctionalunits,includingMS(MobileStation),NSS(NetworkSubSystem),BSS(BaseStationSubsystem),OSS(OperationSupportSubsystem),etc.
19.GSM系统规定的载频间隔为200kHz
ThespecifiedcarrierfrequencyintervalfortheGSMsystemis200kHz.
20.在相同的传播环境中,1800MHz比900Mhz的贯穿损耗小。
1800MHzhasasmallerbreakthroughlossthan900Mhzinthesamepropagationenvironment.
选择题
SingleorMultipleChoices
1.传播模型的选择与覆盖区域的半径有关,一般认为,当覆盖半径大于___C____时,统计型模型的预测精度比较理想。
Selectionofpropagationmodelisrelatedtothecoverageradius.Generally,thestatisticsmodelhasamoredesirablepredictionaccuracywhenthecoverageradiusislargerthanC.
A.100m
B.500m
C.1km
D.35km
2.一般认为,设计蜂窝系统时,使用ErlangB呼损公式,为了便于工程计算,制成了ErlangB表。
ErlangB表直接给出了下列A选项的相互关系:
Generally,theErlangBcalllossformulacanbeusedindesignofacellularsystem.AnErlangBtableiscreatedforeaseofengineeringcalculation.TheErlangBtableshowstherelationshipbetweenAoptions.
A载频数、话音信道数和可提供的话务量;
Numberofcarrierfrequencies,numberofvoicechannelsandavailabletraffic
B人均话务量、话音信道数和可提供的话务量;
Trafficperperson,numberofvoicechannelsandavailabletraffic
C呼损率、话音信道数和可提供的话务量;
Calllossrate,numberofvoicechannelsandavailabletraffic
D呼损率、载频数和可提供的话务量;
Calllossrate,numberofcarrierfrequenciesandavailabletraffic
3.抑制干扰小区对被干扰小区的同频干扰,可采用以下哪些手段?
(ABCE)
Whichofthefollowingmeasurescanbetakentosuppresstheco-frequencyinterferencethattheinterferingcellhasontheinterferedcell?
(ABCE)
A更合理的频率规划Morereasonablefrequencyplanning
B干扰小区天线下倾
Declinationoftheantennafortheinterferingcel
C采用跳频技术Useoffrequencyhoppingtechnology
D干扰小区天线升高
Elevationoftheantennafortheinterferingcell
E降低干扰小区BTS发射功率
DecreaseoftransmissionpowerofBTSfortheinterferingcell
4.较强的同邻频干扰可能带来什么问题?
(ABD)
Whatwillresultfromstrongco-frequencyinterference?
(ABD)
A.话音质量差
Poorvoicequality
B.掉话
Calldrop
C.位置更新频繁
Frequentlocationupdate
D.切换成功率低
Lowhandoversuccessrate
5.适用于密集城区的站型及天线选型是___b_____;
ThebasestationandantennasuitablefordenseurbanareaareB.
A.全向基站;
Omni-directionalbasestation
B.3小区基站,水平65度,增益15.5dbi左右;
Basestationwith3cells,horizontal65degree,about15.5dbigain
C.3小区基站,水平65度,增益18dbi左右;
Basestationwith3cells,horizontal65degree,about18dbigain
D.3小区基站,水平90度,增益15.5dbi左右;
Basestationwith3cells,horizontal90degree,about15.5dbigain
6.具有相同BCCH载波频率的不同基站可以通过D来区分
DifferentbasestationswiththesameBCCHcarrierfrequencycanbedistinguishedby____D____.
A.C1参数C1parameter
B.C2参数
C2parameter
C.电平值Rxlev
LevelvalueRxlev
D.基站识别码BSIC
BaseStationIdentityCode(BSIC)
7.天线的VSWR合理的范围为:
B
ThereasonablerangeofVSWRforanantennais:
B
A.1B.1C.VSWR>1.5
D.VSWR>3.0
8.室内覆盖的的弱点是:
(ABCD)
Thedrawbacksofindoorcoverageare(ABCD).
A忙区
Busyarea
B盲区
Blindarea
C弱区
Weakarea
D冲突区
Conflictarea
9.网络规划与优化中描述场强值通常使用的单位是B
TheunitBisoftenusedtodescribethefieldstrengthvalueduringnetworkplanningandoptimization.
Adb
Bdbm
Cdbd
Ddbi
10.在网络规划中常用到的基站类型有:
(ABCD)
Thetypesofbasestationscommonlyusedinnetworkplanningare:
(ABCD).
A宏基站
Macrobasestation
B微蜂窝
Microcell
C射频拉远
Remoteradiounit
D直放站
Repeater
问答题
Questions
1.简要画出GSM网络规划流程图:
DrawtheflowchartofGSMnetworkplanning.
2.无线网络规划的内容
Pleasedescribewhatshouldbeplannedfortheradionetwork.
1)确定规划区内所需的基站数和相应的站址
Determinethenumberofbasestationsnecessaryintheplannedareaandtheaddressesofsites.
2)确定小区参数:
天线类型、天线高度、方向角、下倾角、有效辐射功率等RF参数
Determinethecellparameters:
antennatype,antennaheight,directionangle,tiltangle,effectiveradiatedpowerandotherRFparameters.
3)确定小区应配置的TRX数
DeterminethenumberofTRXsthatshouldbeconfiguredforthecell.
4)确定小区频率配置
Determinethecellfrequencyconfiguration.
5)确定小区相关无线资源参数
Determinetheradioresourceparametersrelatedtothecell.
6)容量规划、小区规划、频率规划
Capacityplanning,cellplanning,frequencyplanning
7)场强分析、覆盖分析、同邻频干扰分析及话务分析等(验证规划效果)
Fieldstrengthanalysis,coverageanalysis,co-frequencyinterferenceanalysisandtrafficanalysis(verifytheeffectofplanning).
3.请简述规划中上下行链路功率平衡预算的主要目的是什么?
Pleasedescribethemajorpurposesofpowerbalancebudgetfortheuplinkanddownlinkduringtheplanning.
答:
上下行链路功率平衡预算通过调整基站的发射功率,使得覆盖区边界上的点下行接收信号扣除损耗及系统裕量后大于手机接收灵敏度,而该点上行信号到达基站后扣除损耗及系统裕量大于基站接收灵敏度。
Answer:
Thepowerbalancebudgetforuplinkanddownlinkmakes,throughadjustmentoftransmitterpowerofbasestation,thereceiveddownlinksignalatthepointontheedgeofcoveragetobelargerthanthereceiversensitivityofmobilephoneafterdeductingthelossandsystemallowance;andmakestheuplinksignalofthispointthatarrivesthebasestationtobelargerthanthereceiversensitivityofbasestationafterdeductingthelossandsystemallowance.
目的是保证设计系统满足覆盖要求。
降低可能的因为上下行链路不平衡引起的单向通话、提高有效的无线接通率。
也就是准确的上下行链路功率平衡预算是保证在两个方向上具有同等的话务量和通信质量的手段,也关系到小区的实际覆盖范围。
Itaimstomakesurethatthesystemisdesignedtosatisfythecoveragerequirements,reducethepossibleunidirectionalcommunicationduetoimbalanceduplink/downlink,andincreasetheeffectivewirelesscallcompletionrate.Inotherwords,anaccurateuplink/downlinkpowerbalancebudgetisusedtoensuretwodirectionshavethesametrafficandcommunicationquality.Itisalsorelatedtotheactualcoverageofacell.
4.设共有频点10MHz,BCCH的复用方式为4X3,业务信道的复用方式为3X3,不采用跳频时频率规划及容量分析如何?
Supposethefrequencyis10MHz,thereusemodeofBCCHis4X3,andthereuseoftrafficchannelis3X3.Pleasedescribethefrequencyplanningandcapacityanalysiswhenthefrequencyhoppingisnotused.
10MHz共50个频点,去掉1个保护频点和12个BCCH频点,还剩37个频点,则每小区可分得4个业务频点((37-1)/9),总共还剩一个频点,即最大的配置为5+5+5。
每小区可提供的信道数为37个(1BCCH+2SDCCH+37TCH)。
10MHzhas50frequenciesintotal.Besides1protectionfrequencyand12BCCHfrequencies,thereare37frequenciesleft.Soeachcellcanbeassignedwith4trafficfrequencies((37-1)/9),andthereisonefrequencyleft,namelythemaximumconfigurationis5+5+5.Eachcellcanprovide37channels(1BCCH+2SDCCH+37TCH).
5.GSM基站站址的选择原则:
PleasedescribetheprinciplestoselectthelocationofGSMbasestation.
1)站址,并利用其机房、电源及铁塔等设施。
Theexistingtelecommunicationbuilding,postofficeormicrowavestationisusedasthesiteaddress,andtheequipmentroom,powersupplyandtowerofsuchbuildingscanbeused.
2)交通方便、市电可靠、环境安全及占地面积小。
Thetransportationisconvenient,themainsupplyisstable,thesurroundingareaissafe,andtheareaofsiteissmall.
3)在建网初期设站较少时,选择的站址应保证重要用户和用户密度大的市区有良好的覆盖。
Intheinitialphaseofnetworksetupwhereonlyafewofsitesareconstructed,thesitesshouldresideatsuchplacesastocovermajorcustomersandtheurb