電信通信專業(yè)外文翻譯譯文

.PAGE.RadionetworkplanningprocessandmethodsforWCDMAWCDMA無線網(wǎng)絡(luò)規(guī)劃過程和方法AbstractThispaperdescribesthesystemdimensioningandtheradionetworkplanningmethodologyforathirdgenerationWCDMAsystem.Theapplicabilityofeachmethodisdemonstratedusingexamplesoflikelysystemscenarios.Thechallengesofmodelingthemultiserviceenvironmentaredescribedandtheimplicationstothesystemperformancesimulationsareintroduced.摘要本文詳細介紹了系統(tǒng)的維數(shù)和第三代WCDMA系統(tǒng)無線網(wǎng)絡(luò)規(guī)劃方法。證明使用實例的可能的系統(tǒng)方案的每一種方法的適用性。描述了多業(yè)務(wù)環(huán)境中建模的挑戰(zhàn)并且介紹了性能仿真對系統(tǒng)的影響。Keywords:Telecommunicationnetworkplanning,Mobileradio-communication,Codedivisionmultipleaccess,Widebandtransmission,Multipleservicenetwork,Dimensioning,Simulator,Staticmodel,Dynamicmodel,Cellularnetwork.關(guān)鍵詞：電信網(wǎng)絡(luò)規(guī)劃,移動無線電通信,分碼多重存取,寬帶傳輸,多服務(wù)網(wǎng)絡(luò),維數(shù),模擬器,靜態(tài)模型,動態(tài)模型,蜂窩網(wǎng)絡(luò)。Resume<?>ContentsIntroductionII.Initialplanning,systemdimensioningIII.DetailedplanningprocessIV.ExampledimensioningcaseandverificationofdimensioningwithstaticsimulationsV.ComparisonofastatictoadynamicnetworksimulatorVI.Conclusion目錄產(chǎn)品簡介初步規(guī)劃,系統(tǒng)選型示例維數(shù)情況,在靜態(tài)模擬下核實維數(shù)比較靜態(tài)和動態(tài)網(wǎng)絡(luò)模擬器結(jié)論INTRODUCTIONAsthelaunchofthirdgenerationtechnologyapproaches,operatorsareformingstrategiesforthedeploymentoftheirnetworks.Thesestrategiesmustbesupportedbyrealisticbusinessplansbothintermsoffutureservicedemandestimatesandtherequirementforinvestmentinnetworkinfrastructure.Evaluatingtherequirementfornetworkinfrastructurecanbeachievedusingsystemdimensioningtoolscapableofassessingboththeradioaccessandthecorenetworkcomponents.Havingfoundanattractivebusinessopportunity,systemdeploymentmustbeprecededbycarefulnetworkplanning.Thenetworkplanningtoolmustbecapableofaccuratelymodelingthesystembehaviourwhenloadedwiththeexpectedtrafficprofile.Thethirdgenerationcellularsystemswillofferserviceswellbeyondthecapabilitiesoftoday'snetworks.Thetrafficprofile,aswellastheradioaccesstechnologyitselfformthetwomostsignificantchallengeswhendimensioningandplanningaWCDMAbasedthirdgenerationsystem.Thetrafficprofiledescribesthemixtureofservicesbeingusedbythepopulationofusers.Therearealsospecificsystemfunctionalitieswhichmustbemodelledincludingfastpowercontrolandsofthandover.InordertoaccuratelypredicttheradiocoveragethesystemeaturesassociatedwithWCDMAmustbetakenintoaccountinthenetworkmodelingprocess.Especiallythechannelcharacterization,andinterferencecontrolmechanismsinthecaseofanyCDMAsystemmustbeconsidered.InWCDMAnetworkmultipleservicesco-exist.Differentservices<voice,data>havedifferentprocessinggains,Eb/N0performanceandthusdifferentreceiverSNRrequirements.InadditiontothosetheWCDMAcoveragedependsontheloadcharacterization,handoverparameterization,andpowercontroleffects.Incurrentsecondgenerationsystems'coverageplanningprocessesthebasestationsensitivityisconstantandthecoveragethresholdisthesameforeachbasestation.InthecaseofWCDMAthecoveragethresholdisdependentonthenumberofusersandusedbitratesinallcells,thusitiscellandservicespecific.產(chǎn)品簡介推出第三代技術(shù)方法的同時,運營商正在形成他們的網(wǎng)絡(luò)部署策略。無論在對未來服務(wù)需求的估計還是網(wǎng)絡(luò)基礎(chǔ)設(shè)施投資的要求,這些策略必須支持實際的業(yè)務(wù)計劃。使用系統(tǒng)評估的無線接入和核心網(wǎng)絡(luò)組件的尺寸工具,可以實現(xiàn)網(wǎng)絡(luò)基礎(chǔ)設(shè)施的要求評價。在發(fā)現(xiàn)了一個有吸引力的商業(yè)機會時,在系統(tǒng)部署之前,必須通過周密的網(wǎng)絡(luò)規(guī)劃。隨著預(yù)期的流量配置文件加載時,網(wǎng)絡(luò)規(guī)劃工具必須能夠準(zhǔn)確模擬系統(tǒng)的行為。第三代蜂窩系統(tǒng)將提供的服務(wù)遠遠超出了今天的網(wǎng)絡(luò)能力。當(dāng)設(shè)計和規(guī)劃一個基于第三代系統(tǒng)的WCDMA時,流量模板,以及無線接入技術(shù)本身形成兩個最重要的挑戰(zhàn)。流量模板描述了綜合服務(wù)的用戶群。也有特定的系統(tǒng)必須建模,包括快速功率控制和軟切換的功能。為了準(zhǔn)確預(yù)測無線覆蓋與WCDMA系統(tǒng)相關(guān)的功能,必須考慮網(wǎng)絡(luò)的建模過程。特別是溝道表征,并在CDMA系統(tǒng)的情況下,任何的干擾控制機制必須加以考慮。在WCDMA網(wǎng)絡(luò)中多種服務(wù)并存。不同的服務(wù)〔語音,數(shù)據(jù)有不同的處理增益,Eb/N0的性能,因而有不同的接收器SNR的要求。除了那些WCDMA的覆蓋范圍取決于負載特性,交出的參數(shù)和電源控制效果都是如此。在當(dāng)前的第二代系統(tǒng)的覆蓋規(guī)劃處理中,基站的靈敏度是恒定的,對每個基站的覆蓋范圍的閾值是相同的。在WCDMA的覆蓋范圍的閾值的情況下是依賴于用戶的數(shù)量和在所有元件中使用的比特率,因此,這是元件和具體的服務(wù)。TheWCDMAplanningprocesscanbedividedintothreephases:initialplanning<dimensioning>,detailedradionetworkplanningandnetworkoperationandoptimization.Eachofthesephasesrequiresadditionalsupportfunctionslikepropagationmeasurements,KeyPerformanceIndicatordefinitionsetc.Inacellularsystemwherealltheairinterfaceconnectionsoperateonthesamecarrierthenumberofsimultaneoususersisdirectlyinfluencingonthereceivers'noisefloors.Therefore,inthecaseofVMTStheplanningphasescannotbeseparatedintocoverageandcapacityplanning.Inthecaseofthepostsecond-generationsystemsdataservicesstarttoplayanimportantrole.Thevarietyofservicesrequiresthewholeplanningprocesstoovercomeasetofmodifications.Oneofthemodificationsisrelatedtothequalityofservice<QoS>requirements.Sofarithasbeenadequatetospecifythespeechcoverageandblockingprobabilityonly.Alsomoreandmoreonehastoconsidertheindoorandin-carcoverageprobabilities.InthecaseofUMTStheproblemisslightlymoremultidimensional.ForeachservicetheQoStargetshavetobesetandnaturallyalsomet.Inpracticethismeansthatthetightestrequirementshalldeterminethesitedensity.InadditiontothecoverageprobabilitythepacketdataQoScriteriaarerelatedtotheacceptabledelaysandthroughput.Estimationofthedelaysintheplanningphaserequiresgoodknowledgeoftheuserbehaviourandunderstandinginthefunctionsofpacketscheduler.WCDMA規(guī)劃的過程可以分為三個階段：最初的規(guī)劃〔尺寸,詳細的無線網(wǎng)絡(luò)規(guī)劃和網(wǎng)絡(luò)運營與優(yōu)化。每個階段需要額外的支持功能,如傳播測量,關(guān)鍵績效指標(biāo)定義等。每個階段需要其他的支持功能,如傳播測量、關(guān)鍵績效指標(biāo)定義等。在蜂窩系統(tǒng)中,所有的空中接口連接在同一載波上運行,并發(fā)用戶數(shù)直接影響接收機的噪聲層。因此,在VMTS的情況下規(guī)劃階段不能被分離成覆蓋和容量規(guī)劃。在此后的情況下,第二代系統(tǒng)的數(shù)據(jù)服務(wù)開始發(fā)揮重要的作用。各種服務(wù)需要在整個規(guī)劃過程中克服一系列修改。其中一項修改關(guān)系到相關(guān)的服務(wù)質(zhì)量〔QoS要求。到目前為止,它已經(jīng)足夠指定語音覆蓋和阻塞概率。此外,越來越多的人們必須考慮的是室內(nèi)和車內(nèi)覆蓋概率。在UMTS的情況下,問題是稍微多維的。對于每個服務(wù)的QoS目標(biāo)都必須設(shè)置.。在實踐中,這意味著嚴格的要求應(yīng)確定網(wǎng)站密度。除了覆蓋概率的分組數(shù)據(jù)的QoS指標(biāo)與可接受的延遲和吞吐量有關(guān)。在規(guī)劃階段的延遲估計需要用戶行為的良好認知和理解數(shù)據(jù)包調(diào)度程序的功能。Commonfeaturesbetweensecondandthirdgenerationcoveragepredictionalsoexist.Inallthesystemsbothofthelinkshavetobeanalyzed.Incurrentsystemsthelinkstendtobeinbalancewhereasinthecaseofthirdgenerationoneofthelinkscanbehigherloadedthantheother,andthuseitheroneofthelinkscouldbelimitingthecellcapacityorcoverage.Thepropagationcalculationisbasicallythesameforallstandards,withtheexceptionthatdifferentpropagationmodelscouldbeused.Anothercommonfeatureistheinterferenceanalysis.InthecaseofWCDMAthisisneededfortheloadingandsensitivityanalysis,inthecaseofTDMA/FDMAitisessentialforfrequencyallocation.InordertofullyutilizetheWCDMAcapabilities,athoroughunderstandingoftheWCDMAairinterfaceisneededfromthephysicallayertothenetworkmodeling,planningandperformanceoptimization.第二代和第三代之間也存在覆蓋預(yù)測的共同特點。在所有系統(tǒng)中兩個鏈接是必須要進行分析的。在目前的系統(tǒng)中,連結(jié)往往是處于平衡狀態(tài),而在第三代的情況下的鏈接比其他加載更高,因此其中的鏈接可能會限制電池容量或覆蓋。傳播計算所有標(biāo)準(zhǔn)基本上是相同的,與此不同的是不同的傳播模型被應(yīng)用。另一個共同特點是干擾分析。在WCDMA的情況下,這是裝載和敏感度分析所需要的,在TDMA/FDMA的情況下,對于頻率分配它是必不可少的。為了充分利用的WCDMA能力,對WCDMA空中接口的透徹理解,需要來自物理層的網(wǎng)絡(luò)建模,規(guī)劃和性能優(yōu)化。Inthispaperthepre-operationalphaseoftheWCDMAplanningprocess,asdepictedinFigure1indetail,isdiscussed.SectionIIisconcentratingontheinitialplanningissues.TheWCDMAlinkbudgetisintroducedanditisdemonstratedhowdifferentservicesandtheirQoSrequirementsimpactonthesitedensityestimate.InSectionIIIastaticradionetworksimulatorisintroduced.ThemethodologyrequiredinthecoverageandcapacityestimationforWCDMAisdescribedforbothuplinkanddownlink.TopicofSectionIVistodemonstratetheaccuracyofdimensioning:anexampleareaisdimensionedandtheaveragesitedistanceisdetermined.Thedimensioningresultiscomparedwiththeoutcomeofastaticnetworksimulation.InSectionVtheanalysismethodsofthestaticsimulatorareverified.Theverificationwasperformedwithadynamicsystemsimulator.ThepaperisconcludedinSectionVI.在本文中討論了,圖1中所詳細描繪的運行前階段的WCDMA規(guī)劃過程。第二部分主要討論最初的規(guī)劃問題。介紹了WCDMA的鏈路預(yù)算并且證明了不同的服務(wù)和QoS要求對站點密度估計的影響。在第三部分介紹靜態(tài)無線網(wǎng)絡(luò)模擬器。上行鏈路和下行鏈路描述了用于WCDMA的覆蓋范圍和容量估計所需的方法。第四部分的一個主題是為了演示的尺寸精度,例如區(qū)域的尺寸和確定平均站點距離,將尺寸的結(jié)果與靜態(tài)網(wǎng)絡(luò)仿真的結(jié)果作對比。在第五部分驗證了靜態(tài)仿真分析方法。用一個動態(tài)的系統(tǒng)模擬器進行了核查。第六部分對本文做出總結(jié)。INITIALPLANNING,SYSTEMDIMENSIONINGInitialplanning<i.e.systemdimensioning>providesthefirstandmostrapidevaluationofthenetworkelementcountaswellastheassociatedcapacityofthoseelements.Thisincludesboththeradioaccessnetworkaswellasthecorenetwork.Thispaperfocusesupontheradioaccesspartsolely.Thetargetoftheinitialplanningphaseistoestimatetherequiredsitedensityandsiteconfigurationsfortheareaofinterest.Initialplanningactivitiesincluderadiolinkbudget<RLB>andcoverageanalysis,capacityestimation,andfinally,estimationfortheamountofbasestationhardwareandsites,radionetworkcontrollers<RNC>,equipmentatdifferentinterfaces,andcorenetworkelements.Theservicedistribution,trafficdensity,trafficgrowthestimatesandQoSrequirementsareessentialalreadyintheinitialplanningphase.Intheinitialplanningphasethequalityistakenintoaccountintermsofblockingandcoverageprobability.RLBcalculationisdoneforeachservice,andthetightestrequirementshalldeterminethemaximumallowedisotropicpathloss.二。初步規(guī)劃,系統(tǒng)尺寸初步規(guī)劃〔即系統(tǒng)選型為網(wǎng)絡(luò)元素數(shù)量以及這些元素相關(guān)的能力提供最早最快速的評估。這包括無線接入網(wǎng)絡(luò)和核心網(wǎng)絡(luò)。本文僅側(cè)重于無線接入部分。初始規(guī)劃階段的目標(biāo)是估計所需的站點密度和感興趣地區(qū)的現(xiàn)場配置。初步規(guī)劃活動包括無線鏈路預(yù)算〔RLB和覆蓋分析、容量估計,以及最后對基站硬件和網(wǎng)站數(shù)量、無線網(wǎng)絡(luò)控制器〔RNC、不同接口的設(shè)備、核心網(wǎng)絡(luò)元素的估計。服務(wù)分布、交通密度、交通量的增長估計和QoS的要求是初步規(guī)劃階段必不可少的。在最初的規(guī)劃階段質(zhì)量被考慮在阻塞和覆蓋概率內(nèi)。RLB計算完成每項服務(wù),嚴格的要求應(yīng)確定最大允許各向同性路徑損耗。WCDMAspecificitemsintheradiolinkbudgetInthissectiontheWCDMAuplinkanddownlinkbudgetsarediscussed.ToestimatethemaximumrangeofacellaRLBcalculationisneeded.IntheRLBtheantennagains,cablelosses,diversitygains,fadingmargins,diversitygainsetc.aretakenintoaccount.TheoutputoftheRLBcalculationisthemaximumallowedpropagationpathlosswhichinreturndeterminesthecellrangeandthustheamountofsitesneeded.ThereareafewWCDMAspecificitemsinthelinkbudgetifonecomparestothecurrentTDMAbasedradioaccesssystemlikeGSM.Theseincludeinterferencedegradationmargin,fastfadingmargin,transmitpowerincreaseandsofthandovergain.Theinterferencedegradationmarginisafunctionofthecellloading.Themoreloadingisallowedinthesystem,thelargerinterferencemarginisneededinuplink,andthesmalleristhecoveragearea.Theuplinkloadingcanbederivedasfollows,forsimplicitythederivationisperformedwithserviceactivityv=1.TofindouttherequireduplinktransmittedandreceivedsignalpowerforamobilestationMSkconnectedtoaparticularbasestationBSn,thebasicCDMAEb/N0equationisused.Theusual,slightlytheoretical,assumptionisthatIoth,theinterferencereceivedfromtheMSsconnectedtotheothercellsisdirectlyproportional<proportionalityconstanti>toIown,theinterferencereceivedfromtheMSsconnectedtothesameBSnasthedesiredMS.AssumethattheMSkusesbitrateRk,itsEb/N0requirementisPkandtheCDMAmodulationbandwidthisW.Thenthereceivedpowerofthek-thmobile,Pk,atthebasestationitisconnectedto,mustbeatleastsuchthat公式<1>k=lKwhereKnisthenumberofMSsconnectedtoBSn,N=NoW=NfkToWisthenoisepowerinthecaseofanemptycell,Nfisthereceivernoisefigure,kistheBoltzmannconstantandT0istheabsolutetemperature.WCDMA無線鏈路預(yù)算的具體項目在本節(jié)中討論的是WCDMA的上行鏈路和下行鏈路預(yù)算。有必要估計一個單元格的最大范圍的一個RLB計算。在RLB中要考慮天線增益、電纜損耗、分集增益、衰落余量、分集增益等。RLB計算的輸出是最大允許的傳播路徑損耗,這種損耗確定返回的單元格的范圍,從而需要大量的網(wǎng)站。也有少數(shù)的WCDMA的鏈路預(yù)算中的特定項可以與當(dāng)前的基于TDMA的無線接入系統(tǒng)作比較,如GSM。這些措施包括干擾降解保證金、快衰落余量、發(fā)射功率增加和軟切換增益。干擾退化利潤率是元件裝載的一個功能。系統(tǒng)中允許更多的加載,就要在上行鏈路中需要較大的干擾余量和越小的覆蓋區(qū)域。上行負載,可以得出如下簡單的推導(dǎo)進行服務(wù)活動V=1。為了移動臺的MSK連接到一個特定的基站BSn,要用CDMA的Eb/N0基本方程找出所需的上行鏈路的發(fā)送和接收信號功率。通常簡單的理論是假設(shè)Ioth,從連接到其他元件的移動站接收的干擾與Iown接收到的干擾信號成正比〔比例常數(shù)。假設(shè)該MSK使用比特率為RK,則Eb/N0的要求是PK和CDMA調(diào)制帶寬為W。然后,第k個移動峰值,它是連接到在基站處的接收功率,必須至少是這樣的。公式<1>k=lKKN是MSs連接到BSN的數(shù),,N=NoW=NfkToW是一個空單元格情況下的噪聲功率,Nf是接收機的噪聲系數(shù),k是玻耳茲曼常數(shù),T0為絕對溫度。Theinequalitiesin<1>areslightlyoptimisticbecauseitisassumedthatthereisnointerferencefromtheownsignal.Inrealitythisisnotexactlytrueinmultipathpropagationconditions.Equation<1>ishoweverstillchosentoavoidtakingmultipathinterferenceintoaccounttwice.I.e.,theEb/N0requirementsdeterminedfromlinklevelsimulationsarepresentedsothatN0meansonlynoiseandmultipathinterferenceisvisibleinhigherEb/N0requirementtoacertainBERperformance.Solvingtheinequalitiesasequalitiesmeanssolvingfortheminimumrequiredreceivedpower<sensitivity>,Pk:公式<2>IftheEquationsin<2>aresummedoverthemobilestationsconnectedtoBSnthen公式公式<3>since/ow,=~Pk'Ifloadingisdefinedask公式<4>thisloadingdefinitioncanbeenhancedtoincludegainandserviceactivity,v:公式<5>In[12]theuplinkloadingisestimatedusingequation公式<6>wheremisthenumberofservicesused.ThedifferencebetweenEquations<5>and<6>areduetothefactthat<6>doesnotincludesectorisationgainandthatinthederivationstartingfromEquation<1>thedenominatorisIown-Pk+iIow+NratherthanIown+iIown+N,whichisonlythecasewhenPk<<Iown"〔1中的不等式比較理想,因為它是假定不存在干擾的自身信號。在現(xiàn)實中,在多徑傳播條件下,這是不完全正確的。方然而程〔1仍選擇避免兩次考慮多徑干擾。即讓N0表示只有噪聲和多徑干擾,確定鏈路級仿真的Eb/N0要求更高的Eb/N0要求有一定的誤碼率。解決不平等等式意味著解決所需的最小接收功率〔靈敏度,PK：公式<2>k=lK如果方程〔2中的移動臺的總和連接到為BSn的移動站則：公式公式<3>since/ow,=~Pk'Ifloadingisdefinedas公式<4>此加載定義可以被增強,從而包括增益和服務(wù)活動,V：公式<5>使用公式[12]中的上行鏈路負載估計公式<6>其中m是所使用的服務(wù)的數(shù)量。方程〔5和〔6之間的差異是由于,當(dāng)PK<<Iown,〔6并沒有包括,在推導(dǎo)從方程〔1中的分母是IownPK+iIow+?而不是Iown+iIown+?。Thedownlinkdimensioningisfollowingthesamelogicastheuplink.Foraselectedcellrangethetotalbasestationtransmitpoweroughttobeestimated.Inthisestimationthesofthandoverconnectionsmustbeincluded.Ifthepowerisexceededeitherthecellrangeoughttobelimited,ornumberofusersinacellhastobereduced.Fordownlinktheloading<ηDL>isestimatedbasedon公式〔7whereLPmiisthelinklossfromtheservingBSmtoMSi,LPniisthelinklossfromanotherBSn,toMSi,PiisthetransmitEb/N0requirementfortheMSi,includingtheSHOcombininggainandtheaveragepowerraisecausedbyfastpowercontrol,Nisthenumberofbasestations,Iisthenumberofconnectionsinasectorandαiistheorthogonalityfactordependingonmultipathconditions<α=1:fullyorthogonal>.公式：Theterm~"definestheiDL.n=l,n~:mLPniDirectoutputofthedownlinkRLBisthesinglelinkpowerrequiredbyauseratthecelledge.Thetotalbasestationpowerestimationmusttakeintoaccountmultiplecommunicationlinkswithaverage<LPmi>distancefromtheservingbasestation.Furthermore,themulticellenvironmentwithorthogonalitiesaishouldbeincludedinthemodeling.Moreonthedownlinkloadingandtransmitpowerestimationscanbefoundin[13].IntheRLBcalculationinuplinkdirectionthelimitingfactoristhemobilestationtransmitpower,indownlinkdirectionthelimitisthetotalbasestationtransmitpower.Whenbalancingtheuplinkanddownlinkserviceareasbothlinksmustbeconsidered.下行尺寸與上行尺寸按照同樣的邏輯進行的。對于一個選定的單元格范圍應(yīng)該估計總基站發(fā)射功率。在此估計的軟切換連接必須包括在內(nèi)。如果電源被超出,則應(yīng)該限制單元格范圍或必須降低一個小區(qū)中的用戶數(shù)。對于下行鏈路加載〔ηDL的基礎(chǔ)估計公式〔7其中LPmi是從服務(wù)BSm到MSi的鏈路損耗,LPni是從另一個BSn到MSi鏈路損耗,Pi是微星傳輸?shù)腅b/N0要求,包括SHO結(jié)合增益和控制快速功率引起的功率平均提高,N是基站的數(shù)量,I是在一個部分的連接數(shù),αi是取決于多徑條件下〔α=1：完全正交的正交因子。公式：Theterm~"definestheiDL.n=l,n~:mLPni直接輸出的下行鏈路RLB是由在小區(qū)邊緣的用戶所需的單個鏈路功率?？偦竟墓浪?必須考慮到到平均值〔LPmi距離從服務(wù)基站的多條通信鏈路。此外,與正交αi的多小區(qū)環(huán)境應(yīng)包含在建模中。在[13]中可以找到更多下行鏈路上的負荷和傳輸功率估計。在RLB計算在中,上行鏈路方向上的限制因素是移動臺的發(fā)射功率,在下行鏈路方向上的限制因素是總基站發(fā)射功率。必須考慮在平衡在上行鏈路和下行鏈路的服務(wù)區(qū)時的兩個鏈接。Theinterferencedegradationmargintobetakenintoaccountinthelinkbudgetduetoacertainloadingη<eitherinuplinkordownlink>is公式<8>在鏈路預(yù)算中,考慮在一定的負荷η〔無論是在上行鏈路或下行鏈路的干擾退化邊緣率是公式〔8FastfadingmarginorpowercontrolheadroomisanotherCOMAspecificitemintheRLB.Somemarginisneededinthemobilestationtransmissionpowerformaintainingadequateclosedloopfastpowercontrolinunfortunatepropagationconditionslikethecelledge.ThisisapplicableespeciallyforpedestrianuserswheretheEb/N0tobemaintainedismoresensitivetotheclosedlooppowercontrol.Thepowercontrolheadroomhasbeenstudiedmorein[6]and[7].Anotherimpactofthefastpowercontrolisthetransmitpowerincrease.Inthecaseofaslowlymovingmobilestationthepowercontrolisabletofollowthefadingchannelandtheaveragetransmittedpowerincreases.Inowncellthisisneededtoprovideadequatequalityfortheconnectionanddoesnotcauseanyharm,sinceincreasedtransmitpoweriscompensatedbythefadingchannel.Forneighbouringcellshoweverthismeansadditionalinterference.Thetransmitpowerincrease<TxPowerlnc>isusedtoreducethereuseefficiencyaccordingtoEquation<9>.InEquation<4>ishouldbereplacedwithtermTxPowerlnc×iincasethemobilestationtransmitpowerincreaseissignificant.快衰落余量或功率控制余量是在RLB中另一個CDMA特定項目。一定的余量需要在移動站中的發(fā)送功率保持足夠的閉環(huán)傳播條件,例如小區(qū)邊緣的快速功率控制。這是適用的,特別是對于要維持的Eb/N0的更敏感的閉環(huán)功率控制的行人用戶。功率控制余量在[6]和[7]已經(jīng)進行了研究?？焖俟β士刂频牧硗庖粋€影響因素是增加發(fā)射功率。在緩慢移動的移動臺的情況下,功率控制能夠按照衰落信道和平均發(fā)送功率來的增加。這是需要在自己的元件提供足夠的連接質(zhì)量且不會造成任何傷害,因為發(fā)射功率的增加經(jīng)過衰落信道進行補償。然而對于相鄰小區(qū)來說這意味著額外的干擾。發(fā)送功率增加〔TxPowerlnc根據(jù)公式〔9是用來降低的復(fù)用效率。如果移動臺的發(fā)射功率的增加是顯著的,則在公式〔4中i應(yīng)該被替換為TxPowerlnc×I。公式〔9Softhandovergainisdiscussedalreadyin[3].Handovers-softorhard-providegainagainstshadowfadingbyreducingtherequiredfadingmargin.Duetothefactthattheslowfadingispartlyuncorrelatedbetweencells,andbymakinghandoversthemobilecanselectabettercommunicationlink.Furthermore,softhandover<macrodiversity>givesanadditionalgainagainstfastfadingbyreducingtherequiredEb/N0relativetoasingleradiolink.Theamountofgainisafunctionofmobilespeed,diversitycombiningalgorithmusedinthereceiverandchanneldelayprofile.MoreabouttheSHOgaincanbefoundinSectionIIC.軟切換增益[3]中已經(jīng)討論。切換軟、硬對陰影衰落提供增益,減少所需的衰落余量。由于事實上慢衰落是部分元件之間不相關(guān)的通過使越區(qū)切換的移動臺可以選擇一個更好的通信鏈路。此外,軟切換〔宏分集給出了一個額外的增益減少到一個單一的無線鏈路所需的Eb/N0相對抗快衰落。增益量的移動速度是一個函數(shù),用于在接收器和信道延遲分布的分集組合算法。第二節(jié)C可以找到更多關(guān)于SHO增益。ReceiversensitivityestimationInthelinkbudgettheBSreceivernoisedensityisestimatingthenoiseleveloveroneWCDMA—carrier.TherequiredreceiverSNRcontainstheprocessinggainandthelossduetotheloading.Theloadingusedisthetotalloadingduetodifferentservicesonthecarrierinquestion.Therequiredsignalpower<S>dependsontheSNRrequirement,receivernoisefigureandbandwidth.公式〔10Where公式〔11公式〔12whereNfisthereceivernoisefigure,ΚisBoltzmannconstant,Toistheabsolutetemperatureandηistheloading.Insomecasesthebasicnoise/interferencelevelisfurthercorrectedwiththemanmadenoiseterm.B.接收靈敏度估計在鏈路預(yù)算中的BS接收機噪聲密度估計超過一個WCDMA載波的噪音水平。由于裝載,所需的接收SNR中包含的處理增益和損失。由于不同的服務(wù)問題,使用的加載是載體上的總負載。信噪比要求接收器的噪聲系數(shù)和帶寬取決于所需要的信號功率〔S。公式〔10Where公式〔11公式〔12其中NF是接收機噪聲系數(shù),Κ是玻爾茲曼常數(shù),To為絕對溫度,η為加載。在某些情況下,基本的噪聲/干擾水平進一步修正與人為噪聲術(shù)語。ShadowingmarginandsofthandovergainestimationThenextstepistoestimatethemaximumcellrangeandcellcoverageareaindifferentenvironments/regions.TheRLBisestimatingthemaximumallowedisotropicpathloss,fromthatvalueaslowfadingmargin,relatedtothecoverageprobability,hastobesubtracted.Whenestimatingthecoverageprobabilitythepropagationmodelexponentandthestandarddeviationforthelog-normalfadingmustbeset.Iftheindoorcaseisconsideredtheindoorlossisfrom15dBto18dBandthestandarddeviationforlog-normalfadingmargincalculationissetto10-12dB.Inthecaseofoutdoorcoveragetypicalstandarddeviationvalueis7to8dB.Typicalpropagationconstantsrangefrom2.5to4.TraditionallytheareacoverageprobabilityusedintheRLBisforsinglecellcase[1].Therequiredprobabilityis90%to95%andtypicallythisleadsto7-8dBfadingmargin,dependingonthepropagationconstantandstandarddeviationofthelog-normalfading.TheEquation<13>estimatestheareacoverageprobabilityforsinglecellcase:公式〔13Pristhereceivedlevelatcelledge,nisthepropagationconstant,x0istheaveragesignalstrengththresholdandσisthestandarddeviationofthefieldstrength.InrealWCDMAcellularnetworksthecoverageareasofcellsoverlapandthemobilestationisabletoconnecttomorethanjustoneservingcell.Ifmorethanonecellcanbedetectedthelocationprobabilityincreasesandishigherthandeterminedforasingleisolatedcell.Analysisperformedin[2]indicatesthatifthearealocationprobabilityisreducedfrom96%to90%thenumberofbasestationsisreducedby38%,Thisnumberindicatesthattheconceptofmultiserverlocationprobabilityshouldbecarefullyconsidered.Inrealitythesignalsfromtwobasestationsarenotcompletelyuncorrelated,andthusthesofthandovergainisslightlylessthanestimatedin[2].In[3]thetheoryofthemultiservercasewithcorrelatedsignalsisintroduced:公式〔14wherePistheoutageatthecelledge,γisthefadingmargininthecaseofsofthandover,σisthestandarddeviationofthefieldstrengthandfor50%correlationa=b=1/21/2.Withthetheorypresentedforexamplein[1]thisprobabilityatthecelledgecanbeconvertedtotheareaprobability.IntheWCDMAlinkbudgettheSHOgainisneeded.Thegainconsistsoftwoparts:combininggainagainstfastfadingandgainagainstslowfading.Thegainagainstslowfadingisdominatinganditisspecifiedas:公式〔15Ifweassume95%areaprobability,n=3.5andthestandarddeviationis7dBthegainwillbe7.3dB-4dB=3.3dB.Ifthestandarddeviationislargerandtheprobabilityrequirementhigherthegainwillbemore.C:陰影利潤率和軟切換增益估計下一個步驟是估計最大的單元格區(qū)域和在不同的環(huán)境/地區(qū)的單元覆蓋區(qū)域。RLB估計了允許的最大各向同性路徑損耗,從該值中減去與覆蓋概率有關(guān)的慢衰落余量。當(dāng)估計覆蓋概率時,必須設(shè)置。傳播模型的指數(shù)和對數(shù)正態(tài)衰落的標(biāo)準(zhǔn)偏差。如果在室內(nèi)的情況下被認為是室內(nèi)損耗從15dB到18dB,對數(shù)正態(tài)衰落裕度計算的標(biāo)準(zhǔn)偏差設(shè)置為10-12dB。在室外覆蓋的情況下,典型的標(biāo)準(zhǔn)偏差值是7至8分貝。典型的傳播常數(shù)的范圍從2.5到4。RLB中使用的傳統(tǒng)的區(qū)域覆蓋概率是在單電池的情況下的,根據(jù)對數(shù)正態(tài)衰落的傳播常數(shù)和標(biāo)準(zhǔn)偏差,所求的概率是90％至95％,這通常導(dǎo)致7-8分貝衰落余量。式〔13估計的面積覆蓋率為單電池的情況下的概率：公式〔13Pr是在元件邊緣的接收電平,n是傳播常數(shù),x0是平均信號強度閾值,σ是磁場強度的標(biāo)準(zhǔn)偏差。在實際的WCDMA蜂窩網(wǎng)絡(luò)中,元件重疊的覆蓋區(qū)域和移動臺能夠連接到超過一個服務(wù)小區(qū)。如果多個單元格可以被檢測到的位置的概率增加,此概率高于確定為一個單一的孤立小區(qū)。[2]進行分析顯示,如果區(qū)域位置的概率從96％減少到90％,那么基站數(shù)量減少38％,這個數(shù)字表明,應(yīng)慎重考慮多服務(wù)器位置概率的概念。在現(xiàn)實中,從兩個基站的信號不是完全不相關(guān)的,因此軟切換增益略小于[2]中的估計。[3]中介紹了多服務(wù)器的情況下相關(guān)信號的理論。公式〔14其中,P是小區(qū)邊緣中斷,γ是在軟越區(qū)切換的情況下的衰落余量,σ是磁場強度的標(biāo)準(zhǔn)偏差,且為50％的相關(guān)性為a=b=1/21/2。例如在[1]中提出的理論,這一小區(qū)邊緣概率可以被轉(zhuǎn)換為區(qū)域概率。在WCDMA鏈路預(yù)算的SHO增益是必要的。收益由兩部分組成：增益對抗快衰落和慢衰落的增益對相結(jié)合。對慢衰落的增益支配,它被指定為：公式<15>如果我們假設(shè)95％區(qū)域的概率,n=3.5,標(biāo)準(zhǔn)偏差為7dB,增益為7.3dB-4dB=3.3dB.CellrangeandcellcoverageareaestimationOncethemaximumallowedpropagationlossinacellisknown,itiseasytoapplyanyknownpropagationmodelforthecellrangeestimation.Thepropagationmodelshouldbechosensothatitoptimumdescribesthepropagationconditionsinthearea.Therestrictionsofthemodelarerelatedtothedistancefromthebasestation,thebasestationeffectiveantennaheight,themobileantennaheightandthefrequency.OnetypicalexampleformacrocellularenvironmentisOkumura-Hata.Equation<16>presentsanexampleOkumura-Hatapathlossmodelforanurbanmacrocellwithbasestationantennaheightof25m,mobileantennaheightof1.5mandcarrierfrequencyof1950MHz[4].公式<16>Afterchoosingthecellrangethecoverageareacanbecalculated.Thecoverageareaforonecellinhexagonalconfigurationcanbeestimatedwith:公式<17>D：單元范圍和小區(qū)覆蓋范圍估計一旦在單元格中所允許的最大傳播損耗是已知的,所以容易適用于任何已知的單元格范圍估計的傳播模型。應(yīng)選擇在該區(qū)域的傳播條件下描述最佳的傳播模型。模型的限制與從基站的距離、基站有效天線高度,移動臺天線高度和頻率有關(guān)。宏蜂窩環(huán)境的一個典型的例子是Okumura-Hata。方程〔16提出了一個例子,Okumura-Hata城市宏蜂窩路徑損耗模型的基站天線高度25M,移動天線高度1.5m,載波頻率為1950兆赫[4]。公式〔16在選擇單元格范圍的覆蓋區(qū)域可以計算出來。六邊形結(jié)構(gòu)的覆蓋區(qū)域中的一個單元可估計：公式〔17TABLEI.-ExampleofaWCDMARLB.Exempled'unbilandeliaisonradioWCDMA.WhereSisthecoveragearea,risthemaximumcellrangeandKisaconstant,dependingonthenetworktopology.Thenumberofsectorsistypicallyfrom1to3.InthecaseofWCDMAreasonablevaluesareupto6sectors.Inthecaseof6sectorstheestimationofthecellcoverageareabecomesproblematic,sinceasix-sectoredsitedoesnotnecessaryresembleahexagon.Aproposalforthecellareacalculationatthisstageisthattheequationfortheomnicaseisusedalsointhecaseof6sectorsandthelargerareaisduetoahigherantennagain.Themoresectorsareusedthemorecarefulsofthandoveroverheadhastobeanalysedtoprovideanaccurateestimate.InTableIIsomeoftheK-valuesarelisted.TABLEII.--K-valuesforthesiteareacalculation.Valeursduparam~treKpourlecalculd'unezonedecouvertureautourd'unsiteCapacityandcoverageanalysisintheinitialplanningphaseOncethesitecoverageareaisknownthesiteconfigurationsintermsofchannelelements,sectorsandcarriers,andsitedensity<cellrange>hastobeselectedsothatthesupportedtrafficdensitycanfulfiltherequirements.AnexampledimensioningcasecanbeseeninSectionIV.TheWCDMARLBisslightlymorecomplexthantheTDMAone.Thecellrangedependsonthenumberofsimultaneoususers<numberofchannels/usersintermsofinterferencemargin,seeEquation<6>>.Thusthecoverageandcapacityareconnectedandalreadyintheverybeginningtheoperatorshouldhaveknowledgeandvisionofthesubscriberdistributionandgrowthsinceithasadirectimpactonthecoverage.Findingthecorrectconfigurationforthenetworksothatthetrafficrequirementsaremetandthenetworkcostminimisedisnotasimpletask.Thenumberofcarriers,numberofsectors,loading,numberofusersandthecellrangeallhaveanimpactontheresult.表一WCDMARLB的例子其中,根據(jù)網(wǎng)絡(luò)的拓撲結(jié)構(gòu),S為在覆蓋區(qū)域中,r是最大的單元格范圍,K是一個常數(shù)。扇區(qū)數(shù)通常是1至3個。在WCDMA的情況下,合理的值是6個扇區(qū)。在6個扇區(qū)的情況下的覆蓋區(qū)域的估計成為問題,因為一個六扇區(qū)站點沒有必要像六邊形。在此階段的小區(qū)面積計算的提案是,全方位的情況下的方程也適用于在6個扇區(qū)的情況下和由于更高的天線增益引起的更大的區(qū)域。使用的扇區(qū)越多,那么對軟越區(qū)切換系統(tǒng)開銷的分析要更加小心,為了提供精確的估計。表表Ⅱ中的K值被列出。表II地盤面積計算的K值。E.容量和覆蓋分析的初步規(guī)劃階段一旦網(wǎng)站覆蓋區(qū)域被稱為站點配置,無論在通道元素,行業(yè)和運營商,和站點密度〔單元格范圍和交通密度,都必須進行選擇以便能滿足要求。在第IV節(jié)可以看到一個尺寸的情況例子。WCDMARLB比TDMA稍微復(fù)雜一點。單元格區(qū)域取決于并發(fā)用戶數(shù)〔數(shù)量的頻道/用戶的干擾余量,見公式〔6。這樣的覆蓋范圍和容量被連接并且操作者在最開始就對用戶分布和增長具備應(yīng)有的知識和遠見,因為它的覆蓋范圍有直接的影響。尋找正確的網(wǎng)絡(luò)配置使這樣的交通要求得到滿足并且網(wǎng)絡(luò)成本最小化不是一個簡單的任務(wù)。載波數(shù),扇區(qū)數(shù),加載,用戶數(shù)和單元格范圍都對結(jié)果有一個影響。III.DETAILEDPLANNINGPROCESSIntroductiontoastaticradionetworkplanningsimulatorInthisstudythesimulatorfirstintroducedin[9]wasused.Itisofstaticnatureandneedsasinputsadigitalmap,thenetworklayoutandthetrafficdistributioninformofadiscreteusermap.Eachoftheuserscanhavedifferentterminalspeedandusesadifferentservice<bitrate,activityfactor,whichbothcanbedifferent’foruplinkanddownlink>.ThereforeeachmobilestationgetsassignedanindividualEb/N0requirementimportedfromlinklevelsimulations.Thesimulatoritselfconsistsofbasicallythreeparts-initialisation,combineduplinkanddownlinkanalysisandpostprocessingphase.Followingtheinitialisationpart,roundafterroundinthemainpartofthetool,boththeuplinkanddownlinkforallmobile