GSM網(wǎng)絡容量規(guī)劃研究-外文譯文

中文譯文：GSM網(wǎng)絡容量規(guī)劃隨著GSM移動業(yè)務的迅猛發(fā)展，在保證通信質(zhì)量的前提下最大限度地提高GSM網(wǎng)絡容量始終是網(wǎng)絡運營商們孜孜以求的目標。GSM擴容的傳統(tǒng)方法是小區(qū)分裂與頻段擴展，但目前得到新的頻譜資源的可能性已經(jīng)不大，在話務密集地區(qū)因受到干擾的限制，小區(qū)分裂亦舉步維艱，因而采用更加緊密的頻率復用技術、建立微蜂窩/微微蜂窩、建設SM900/1800雙頻網(wǎng)絡以及進行網(wǎng)絡優(yōu)化等已經(jīng)成為解決GSM網(wǎng)絡容量的重要手段。1小區(qū)分裂技術小區(qū)分裂技術是增加網(wǎng)絡容量的理所當然的首選方案。GSM建網(wǎng)初期，主要是解決覆蓋問題。在頻譜資源寬裕的地區(qū)/時期，隨著用戶的增加，可將原來的小區(qū)分裂成更多的覆蓋面積較小的小區(qū)或者增加原有小區(qū)的載頻數(shù)，從而達到擴容的目的。通過小區(qū)分裂或新增載頻，全網(wǎng)基站數(shù)增加，全網(wǎng)載頻數(shù)、信道數(shù)、話務量、用戶數(shù)等均大幅度增加。小區(qū)分裂提高頻譜利用率的關鍵在于減小了單位小區(qū)的面積。選擇小區(qū)分裂擴容法應遵循以下原則:確保已建基站可繼續(xù)使用;應保持頻率復用方式的規(guī)則性與重復性;盡量減少或避免過渡區(qū);確保今后可繼續(xù)進行小區(qū)分裂。全向小區(qū)分裂為全向小區(qū)的方法主要有1：3分裂法;全向小區(qū)分裂為全向及走向小區(qū)的方法有：1：7分裂法;全向小區(qū)分裂為定向小區(qū)的方法有：1×3×4分裂法及1×6×3分裂法;定向小區(qū)分裂為定向小區(qū)的方法有：六角形邊中心分裂法及六角形頂點分裂法。2頻段擴展和頻率緊密復用技術頻段擴展當然是擴容的理想手段，但在現(xiàn)有情況下，得到新的頻譜的可能性不大。目前聯(lián)通在900MHz頻段有6MHz的資源，除個別熱點地區(qū)外，暫時還能基本滿足需要。電信GSM五期擴容后GSM網(wǎng)頻段范圍為：898.6-908.8MHz，共10.2MHz。本次期擴容原則上計劃將A網(wǎng)頻段延伸至885.0125MHz，GSM網(wǎng)頻段向下擴展至14.4MHz，使用23-94號頻點。目前，電信G網(wǎng)基站在許多地區(qū)已十分密集，部分基站間的距離只有四五百米，合適站址的選取已越來越困難。站間距離太近，導致了同頻及鄰頻干擾的增大。此外，天線增益越高，其在垂直面內(nèi)的波束寬度也就越窄，若站距太近，則移動臺處于天線主波束外的概率大大增加。另外，A網(wǎng)移頻的余地也不是很大，因此，頻譜擴展的空間十分有限。不過，由于GSM采用了諸如GMSK、均衡調(diào)制、交織編碼等手段，特別是還提供了其它一些旨在提高頻譜效率的技術，如跳頻、非連續(xù)發(fā)射、功率控制、半速率信道、分集接收以及移動輔助切換等，從而降低了網(wǎng)絡對同頻與鄰源干擾指標的要求，使得頻率的緊密復用成為可能。跳頻,跳頻就是載頻按某種頻率序列進行跳變，它包括基帶跳頻與射頻跳頻兩種。跳頻的作用是提供了頻率分集，提高了系統(tǒng)的抗干擾、抗衰落能力。非連續(xù)發(fā)射,采用DTX技術，可降低系統(tǒng)總的干擾水平。功率控制,這也是降低干擾從而提高容量的有效手段。半速率信道,這可使系統(tǒng)容量增加一倍。分集,分集有多種形式，利用分集技術，可以改善系統(tǒng)抗衰落的能力。3采用更緊密的頻率復用技術在頻段受到限制的情況下，采用更緊密的頻率復用方式無疑是提高系統(tǒng)容量最直接的方法之一。GSM中可以使用的頻率復用方法主要有肝：7小區(qū)復用方式、4×3復用方式、3×3復用方式，4×3與3×3的混合復用方式、2×6復用方式、1×3復用方式以及同心圓技術與多重復用MRP方式等等。7個基站區(qū)的復用方式:這種7個基站區(qū)為一個復用組的復用方式適用于話務量較低或用戶密度較小的地區(qū)，一般為全向基站，其D/R=4.58，同頻復用距離較遠。4×3復用方式:這是“900MHzTDMA數(shù)字公用陸地蜂窩移動通信網(wǎng)絡技術體制”建議采用的復用方式，也是GSM系統(tǒng)中最常用和最典型的復用方式。對于三葉草60度天線，其D/R=6;對于120度天線，其D/R=3.46采用三葉草60度無線時同頻干擾性能更好。3×3復用方式:這也是“900MHzTDMA數(shù)字公用陸地蜂窩移動通信網(wǎng)絡技術體制”建議采用的復用方式。3×3復用方式與跳頻、DTX、功率控制一起使用，可到同頻干擾要求。但帶寬在6MHz以下時，不能提供足夠的跳頻增益，因此性能不佳。2×6復用方式:這是Motrola提出的用以解決高話務地區(qū)頻率復用的方法。該方法在不同天線方向上有著不同的頻率復用程度，其D/R小于3×3復用方式。1×3復用方式:這一方式是目前最緊密的復用方式，其主要特點為：適用于頻帶較窄，容量比較集中，不需很多基站的地區(qū);可在較小的基站數(shù)下提供較大容量;需要采用部分加載方法，即載頻不能用滿，收發(fā)信機數(shù)目為載頻的一半左右;需要采用射頻跳頻、功率控制、不連續(xù)發(fā)射、天線分集等技術，以降低干擾;不需改變現(xiàn)有網(wǎng)絡結構。不過，雖然這一方式頻率利用率很高，但系統(tǒng)干擾增加很大，如采用的抗干擾措施不夠有效，可能對網(wǎng)絡質(zhì)量產(chǎn)生較大影響，因此應謹慎使用。同心圓技術:同心圓技術就是將通常的小區(qū)分為外層和內(nèi)層，外層的覆蓋范圍為傳統(tǒng)的蜂窩小區(qū)，而內(nèi)層的覆蓋范圍則主要集中在基站附近。另外，內(nèi)外層的頻率復用系數(shù)一般也不同，外層一般用4×3復用方式，而內(nèi)層則采用更緊密的復用方式，如3×3、2×3或1×3等方式。根據(jù)同心圓的實現(xiàn)方式不同，可分為普通同心圓與智能雙層網(wǎng)兩種，兩者的主要區(qū)別在于內(nèi)層的發(fā)射功率與內(nèi)外層的切換算法。普通同心圓內(nèi)層的發(fā)射功率一般要低于外層，從而降低了同頻干擾，其內(nèi)外層的切換一般是基于功率與距離的。而IUO內(nèi)外層的發(fā)射功率是完全相同的，并基于C/I進行切換。普通同心圓對容量的提高約為10%-30%左右，提高量不大，IUO方式對容量提高相對較大，一般為20%-40%，并能在提高容量的基礎上保證通話質(zhì)量。MRP方式:MRP方式就是將所有可用載頻分為幾組，每一組載頻作為獨立的一層，不同層的頻率采用不同的復用方式，頻率復用逐層緊密。為保證BCCH的安全，MRP中用于BCCH的載頻數(shù)應不少于12個。按TCH分組方法的不同，MRP又可分為嚴格的MRP與改進的MRP。MRP復用方式有以下幾個特點：可較大程度提高容量，在7.2MHz帶寬情況下，比4×3復用率提高47%;信道分配靈活;可釋放出一些頻率用于微蜂窩;采用基帶跳頻，較易實現(xiàn)。在使用MRP時，應注意以下問題:必須采用跳頻、功率控制、DTX等抗干擾手段，這也是MRP技術應用的前提;采用MRP技術時，應注意頻率分配的順序。一般應先分配BCCH，然后分配TCH5，接著分配TCH4，直至TCH1;不同區(qū)域基站的頻率應分別規(guī)劃;根據(jù)具體的干擾情況，調(diào)整鄰區(qū)設置。從深圳及山東等地的使用情況看，MRP技術可根據(jù)容量需求及話務分布情況靈活進行頻率規(guī)劃，可逐步提高網(wǎng)絡容量，比僅使用3×3復用網(wǎng)絡容量高，與1×3復用相比對網(wǎng)絡質(zhì)量影響較小，采用的技術如跳頻、功率控制、不連續(xù)發(fā)射是GSM系統(tǒng)應具備的技術，在硬件設備及軟件上無其它特殊要求，是目前應用得比較成功的頻率復用方式。4微蜂窩與微微蜂窩技術采用微蜂窩及微微蜂窩技術也是提高網(wǎng)絡容量的有效方法之一。在以下兩類地區(qū)可考慮使用微蜂窩：一是“熱點”地區(qū)。最主要的“熱點”地區(qū)是如大型賓館、飯店、寫字樓、大型商場、娛樂場所及車站、碼頭、機場等等。二是為解決全網(wǎng)容量問題，在現(xiàn)有宏蜂窩下再建一個連續(xù)覆蓋的微蜂窩。宏蜂窩用于覆蓋低話務密度地區(qū)，以解決高速移動用戶的覆蓋;微蜂窩用于覆蓋高話務地區(qū)，以解決低速運動用戶的覆蓋。微蜂窩具有以下優(yōu)點：設備體積小，安裝簡單靈活，可快速解決熱點地區(qū)的容量與覆蓋問題;無需改變網(wǎng)絡結構，無需特殊手機;采用后容量可明顯提高。微蜂窩也具有以下一些缺點：為解決大城市的連續(xù)覆蓋，需要大量的微蜂窩，投資十分龐大;采用分層結構時，網(wǎng)絡結構復雜，增加了頻率規(guī)劃的難度。目前，浙江電信已大量采用了微蜂窩。對于浙江聯(lián)通，建議按如下思路發(fā)展微蜂窩：在宏蜂窩覆蓋不到而話務量又很大的地點，應使用微蜂窩作為覆蓋補充，而話務量很高的商業(yè)街道等地則可采用多層網(wǎng)形式進行連續(xù)覆蓋。為解決整個大型建筑物的覆蓋，可考慮采用室內(nèi)覆蓋系統(tǒng)。5采用GSM900/1800雙頻系統(tǒng)在話務量特別大或頻率資源特別緊張的地區(qū)，可考慮適時推出GSM900/1800雙頻網(wǎng)絡。雙頻系統(tǒng)具有以下優(yōu)點：除射頻部分外，GSM1800系統(tǒng)具有與GSM900系統(tǒng)基本相同的軟硬件結構;兩網(wǎng)絡拓撲結構相同，可共用MSC、HLR、BSC及OMC;兩網(wǎng)絡可共站址，可充分利用機房、傳輸、電源、空調(diào)及其它配套設施，大大節(jié)省建設投資與日常維護費用;雖然900MHz與1800MHz電波的傳播特性不盡相同，但GSM1800與GSM900的無線頻率規(guī)劃方法及工具卻基本相同;GSM1800無線覆蓋范圍小，小區(qū)半徑小，覆蓋相同的區(qū)域需要較多基站，因此提高了單位面積的網(wǎng)絡容量;由于兩者原理與系統(tǒng)結構相同，可以節(jié)約網(wǎng)絡運行維護及人員培訓費用。在建設雙頻網(wǎng)絡的過程中，應注意以下幾個問題：雙頻系統(tǒng)的建設應視具體情況區(qū)別對待，應堅持解決話務密集地區(qū)為重點的方針，并要充分利用現(xiàn)有的GSM900系統(tǒng)的設備，將兩者有機結合。對于話務量較小的地區(qū)，雙頻網(wǎng)絡可共用MSC、BSC等設備，甚至可共基站，這樣可靈活配置網(wǎng)絡，為未來的擴容留出余地。對于話務量相對較大的地區(qū)，應考慮將兩者的交換機分開設置。這可以減輕原有的GSM900交換機的壓力，并降低實施GSM1800系統(tǒng)工程時對GSM900系統(tǒng)的影響。應盡可能共基站，以節(jié)省建設投資與維護費用。應減少雙頻切換，盡量讓GSM900系統(tǒng)保證覆蓋，而GSM1800系統(tǒng)充分吸收話務。這可通過調(diào)整兩系統(tǒng)間的切換算法及切換電平門限等方法而實現(xiàn)。在建網(wǎng)時應盡量選用高增益的天線、低損耗的饋線。因在GSMPhase2中增補了許多性能，信令種類相對增多，因此，在A接口的信令鏈路配置上應有一定的冗余度。6定期進行網(wǎng)絡優(yōu)化隨著網(wǎng)絡規(guī)模與復雜度的不斷增加，定期進行網(wǎng)絡優(yōu)化已日顯緊迫，網(wǎng)絡優(yōu)化已成為間接提高網(wǎng)絡容量的一種十分有效的手段。網(wǎng)絡優(yōu)化是在系統(tǒng)正常運行下對系統(tǒng)的一個全范圍的調(diào)整，通過對網(wǎng)絡資源的經(jīng)常性調(diào)整，可使網(wǎng)絡實時地適應移動通信網(wǎng)動態(tài)變化的要求。網(wǎng)絡優(yōu)化的基本步驟包括：網(wǎng)絡數(shù)據(jù)的收集。主要包括：通過場強測試而掌握無線覆蓋情況;通過呼叫質(zhì)量的測試，從用戶的角度去了解網(wǎng)絡情況;通過OMC的話務報告，掌握話務分布情況;通過收集頻率規(guī)劃數(shù)據(jù)，了解小區(qū)頻率規(guī)劃的合理性;通過采集交換機數(shù)據(jù)，了解交換機運行情況等等。對收集到的數(shù)據(jù)進行分析，并依據(jù)分析結果進行以下幾方面的網(wǎng)絡調(diào)整：提高交換機的處理效率、增加容量;信道數(shù)調(diào)整、基站位置變更、盡量利用高大建筑物作隔離;天線位置的變更、DownTilt角度的適當調(diào)整;切換參數(shù)、頻率等的調(diào)整。7建議綜合考慮無線覆蓋要求及工程建設的經(jīng)濟合理性與時間緊迫性，我們認為提高GSM網(wǎng)絡容量的一般方法是：首先，采用宏蜂窩，并用小區(qū)分裂技術，建設更多的小的宏蜂窩;其次，采用較緊密的頻率復用方式，以提高頻率利用率;第三，在“熱點”地區(qū)及重要場所建立微蜂窩與微微蜂窩;第四，采用雙頻系統(tǒng)。在上述四種方法中，還應同步進行網(wǎng)絡的優(yōu)化。

原文：ImprovetheGSMnetworkcapacityplanningWiththerapiddevelopmentofGSMmobilebusiness,andensuringthequalityofcommunicationsunderthepremiseofmaximizeGSMnetworkcapacityisalwaysnetworkoperatorssought-aftergoal.ThetraditionalmethodsofGSMexpansionisthebandsplitandexpansion,butnowgetnewspectrumresourcesthepossibilityisnotbig,inthecallcentersforinterferencewiththelimit,districtdivisionalsocrippled,soitismorecloselyfrequencyreusetechnology,establishingmicrocells/slightlyhoneycomb,constructionSM900/1800double-frequencynetworkandnetworkoptimizationsolutionGSMnetworkcapacityhasbecometheimportantmeans.1Districtsplittechnology Districtsplittechnologyistoincreasethecapacityofthenetworkcoursepreferredplan.GSMearlyarrangement,themainproblemistosolvethecover.Inthespectrumresourcesbounteousarea/period,alongwiththeincreaseoftheuser,butwilltheoriginaldistrictsplitintomorecoverageareaislesserareaorincreasethenumberoforiginaltransmits,soastoachievethepurposeofexpansion.Throughthevillagesplitortransmitsnew,overthebasestationnumber,number,numberofchannel,whichtransmits,traffic,subscribersareincreasedsubstantially.Improvetheutilizationratioofthecommunitydividedspectrumkeyliesintheareaofreducingtheunitarea.Choosedistrictsplitexpansionmethodshallcomplywiththefollowingprinciples:ensurethathasbuiltthebasestationcancontinuetouse;shouldholdthefrequencymultiplexingmethodofregularityandrepeatability;trytoavoidorreducethetransitionzone;toensurethatfuturemaycontinuedistrictdivision.Thesplitinthevillagetovillagetothemainmethods1:3anti-secessionlaw;Thesplitinthevillagetovillagetothemethodandtohave:"anti-secessionlaw;Thevillagefordirectionaldistricttosplitthemethodsare:1x3x4anti-secessionlawand1x6×3anti-secessionlaw;Directionaldistrictsplitthemethodfordirectionalhave:hexagonalsidecenteranti-secessionlawandhexagonalvertexanti-secessionlaw.2TheexpansionandthefrequencybandclosemultiplexingtechniqueFrequencyband,ofcourse,istheidealofcapacityexpansionmethod,butinthecurrentcase,getnewspectrumisunlikely.Atpresentinthe900MHzbandunicom6MHzresources,inadditiontotheindividualthehotspot,cansatisfytheneedforbasic.TelecomGSMfiveperiodexpansionafterGSMnetsfrequencyrangefor:898.6-908.8MHz,total10.2MHz.TheexpansionplaninprincipleofAnetworkextendstothebandwillbe885.0125MHz,GSMnetsfrequencybanddownto14.4MHzexpansion,theuseof23-94numberfrequency.Atpresent,thetelecomGnetsbasestationinmanyareasalreadyverycrowded,partofthedistancebetweenthebasestationonly-meters,theappropriateselectionofhailhasmoreandmoredifficult.Thedistancebetweenthestandingtooclose,leadingtothesamefrequencyandadjacenttheincreaseoffrequencyinterference.Inaddition,thehighertheantennagain,therestrictedinthebeamwidthofthenarrow,ifstandtooclosetothedistance,themobileinantennabeamoftheLordtheprobabilityincreasegreatly.Inaddition,Anetsfrequencyshiftroomalsoisnotverybig,therefore,thespectrumofthespaceexpandisverylimited.However,duetotheGSMsuchasGMSK,balancedmodulation,mixedcodingmethod,especiallyalsoprovidessomeotheraimstoimprovespectrumefficiencytechnology,suchasfrequencyhopping,thecontinuousfiring,powercontrol,halfratechannel,diversityandmobileauxiliaryswitch,receive,soastoreducethenetworkofthesamefrequencyandadjacentinterferencesourceindexrequest,thefrequencyoftheclosereusepossible.hopping.Frequencyhoppingisaccordingtosomefrequencytransmitsjumpingintheseries,itincludesbasebandfrequencyhoppingandrffrequencyhoppingtwokinds.Frequencyhoppingroleistoprovidethefrequencydiversity,andimprovethesystemofanti-disturbanceability,resistancetodecline.Thecontinuousfiring.UsingDTXtechnology,mayreducethesystemoveralllevelofinterference.Powercontrol.Thisisalsoreduceinterferencesoastoimprovethecapacityoftheeffectivemeans.Halfratechannel.Thiscanmakethesystemcapacitydoubled.Diversity.Diversityhavevariousforms,usediversitytechnology,canimprovetheabilityofthesystemofdecline.3Thecloserfrequencymultiplexingtechnique Inthespectrumoflimitedcircumstances,adoptmorecloselyfrequencymultiplexingmethodisundoubtedlyimprovesystemcapacityofoneofthemostdirectway.CanyouuseGSMfrequencymultiplexingmethodmainlyhaveliver:7villagemultiplexingmethod,4x3multiplexingmethod,3by3multiplexingmethod,4x3and3by3mixedmultiplexingmethod,2x6multiplexingmethod,1x3multiplexingmethodandConcentriccirclestechnologyandMultiplereuseMRPstyleandetc.sevenofthebasestationmultiplexingmethod:Thesevenbasestationareaforareusethereuseofthegroupusedinlowtrafficwayoruserdensitysmallerareas,forthegeneraltobasestation,theD/R=4.58,withfrequencymultiplexingdistanceisfarther.4x3multiplexingmethod:Thisis"900MHzTDMAdigitalpubliclandcellularmobilecommunicationnetworktechnologysystem"recommendedthereuseoftheway,andisalsothemostcommonandGSMsystemthemosttypicalmultiplexingmethod.Forclover60degreesantenna,theD/R=6;For120degreesantenna,theD/R=3.46theclover60degreeswhenwirelesswithfrequencyinterferencebetterperformance.3by3multiplexingmethod:Thisis"900MHzTDMAdigitalpubliclandcellularmobilecommunicationnetworktechnologysystem"recommendedthereuseoftheway.3by3multiplexingmethodandfrequencyhopping,DTX,powercontrolareusedtogether,withfrequencyinterferencerequirements.Butinthefollowing6MHzbandwidth,can'tprovideenoughfrequencyhoppinggain,sopoorperformance.2x6multiplexingmethod:ThisisMotrolaproposedtosolvehightrafficareasoffrequencyreusemethod.Themethodinthedirectionofthedifferentantennahasadifferentfrequencyreusedegree,theD/Rlessthan3by3multiplexingmethod.1x3multiplexingmethod:Thiswayisthemostcloselymultiplexingmethod,itsmainfeatures:Applicabletoanarrowfrequencyband,capacitymoreconcentrated,donotneedmanyofthebaseareas;ButinsmallerNumbersprovidelargerbasestationcapacity;Theneedtopartoftheloadingmethods,namelytransmitscan'tusefull,sendandreceivelettermachineforabouthalfthenumbersoftware-processable;Needtoadoptrffrequencyhopping,powercontrol,discontinuouslaunch,antennadiversitytechnologyetc,inordertoreduceinterference;Donotneedtochangetheexistingnetworkstructure.But,althoughthiswayfrequencyutilizationrateisveryhigh,butthesystemdisturbanceincreaseisverybig,ifuseanti-interferencemeasuresnoteffective,mayhavegreatinfluenceonthequalityofnetwork,soshouldbeusedwithcaution.concentriccirclestechnology:Technologyistheusualconcentriccirclesareadividedintoouterandtheinner,theouterlayerofthecoverageforthetraditionalcellularvillage,andtheinnercoveragearemainlyconcentratedinthebasestationnearby.Inaddition,insideandoutsideofthecoefficientoffrequencyreusearealsodifferent,outergeneraluse4x3multiplexingmethod,andtheinnerusedtheclosermultiplexingmethod,suchas3by3,2x3or1x3ways.Accordingtotherealizationoftheconcentriccirclesindifferentways,canbedividedintoordinaryconcentriccirclesandintelligentdoublenets(IUO)twokinds,theessentialdifferencebetweenboththelaunchoftheinnerpowerandinternalandexternallayerofswitchingalgorithm.Thelaunchoftheinnerordinaryconcentriccirclesofpoweringeneraltobelowouter,soastoreducethesamefrequencyinterference,whichgenerallyisbasedontheouterlayeroftheswitchpoweranddistance.AndIUOinsideandoutsideofthelayerarequitethesametransmissionpower,andbasedonC/Iswitch.Toimprovethecapacityofordinaryconcentriccirclesabout10%-30%orso,improvequantityisnotbig,IUOwaytoimprovetherelativelylargecapacity,aregenerally20%-40%,andcanimprovethecapacityinbasedonthecallqualityguarantee.MRPway:MRPwaywillallavailableisdividedintoseveralgroupstransmits,eachgroupasaseparatelayertransmits,thefrequencyofthedifferentlayerswithdifferentmultiplexingmethod,frequencyreuseclosestepbystep.ToensurethesafetyoftheBCCH,usedintheBCCHtransmitstheMRPnumbershouldnotlessthan12.AccordingtothedifferentmethodofgroupingTCH,MRPandcanbedividedintostrictMRPandimprovedMRP.MRPmultiplexingmethodhasthefollowingfeatures:Largecapacitycanbeimproved,in7.2MHzbandwidthcases,than4x3reuseimprovetherateof47%;Channelallocationflexible;Canreleaseasomefrequenciesusedformicrocells;Usingbasebandfrequencyhopping,easiertoachieve.InusingMRP,shouldpayattentiontothefollowingquestions:Mustusefrequencyhopping,powercontrol,suchasDTXanti-jammingmethod,thisalsoisthepremiseofMRPtechnologyapplication;UsingMRPtechnology,attentionshallbepaidtotheorderoffrequencydistribution.GenerallyshouldfirstBCCHdistribution,andthenTCH5distribution,thenTCH4distribution,untilTCH1;Differentareaofthebasefrequencyrespectivelyplanning;AccordingtothespecificinterferenceofadjustmentadjacentregionsSettings.Fromshenzhenandshandong,astheuseoftheland,wecanseetheMRPtechnologycanaccordingtocapacitydemandandtrafficdistributionforflexiblefrequencyplanning,butgraduallyimprovenetworkcapacitythanusingonly3by3reusenetworkcapacity,high,and1x3reusecomparedtothenetworkqualitylessinfluence,thetechnologysuchasfrequencyhopping,powercontrol,discontinuouslaunchisGSMsystemshouldhavetechnology,inthehardwareequipmentandsoftwarewithoutotherspecialrequirements,isthepresentapplicationmoresuccessfulfrequencymultiplexingmethod.4MicrocellsandslightlycellulartechnologyAdoptingmicrocellularandslightlycellulartechnologyimprovenetworkcapacityisoneoftheeffectiveways.Inthefollowingtwotypesofareacanconsidertousemicrocells:Oneisthe"hotspots"area.Themain"hotspots"suchaslargeareaishotels,restaurants,officebuildings,shoppingmall,entertainmentandstations,docksandairports,andsoon.itistosolvetheentirenetworkcapacityproblemsinexistingundermacrotobuildhoneycombacontinuouscoverageofthemicrocells.Macrohoneycombusedtocoverlowtrafficdensityareas,inordertosolvethehigh-speedmobileuserscoverage;Microcellsusedtocoverhightrafficareas,inordertosolvethelowspeedmovementofusercovered.Microcellshasthefollowingadvantages:Theequipmentissmall,easyinstallationflexibility,canquicklysolvehotspotsofcapacityandcoveringproblems;Neednotchangethenetworkstructure,toneednotspecialmobilephones;Aftercanobviouslyincreasethecapacity.Microcellsalsohasthefollowingsomedisadvantages:Tosolvethebigcitiesforcover,needalotofmicrocells,isveryhugeinvestment;Thelayeredstructure,thenetworkstructureiscomplex,increasedfrequencyplanningofdifficulty.Atpresent,zhejiangtelecomhasconsiderableexperiencewithmicrocells.Forzhejiangunicom,Suggestionsaccordingtothefollowingtrainofthoughtdevelopmentmicrocells:inthemacrocellularcoverageandtrafficandlessthanaplace,shouldusethecellularcoverageasacomplement,andhighcommercialstreettrafficandbyusingmulti-levelnetsformcanbecontinuouscoverage.Tosolvethelargebuildingcover,canconsidertouseindoorcoveragesystem.5TheGSM900/1800double-frequencySystemInthetrafficspecialbigorfrequencyresources,especiallynervousarea,canconsiderreleasingGSM900/1800double-frequencynetwork.Thesystemhasthefollowingadvantagescycle:Inadditiontotheradiofrequencypart,GSM1800systemhasGSM900systemandbasicsamehardwareandsoftwarestructure;Twonetworktopologystructureissame,canbeSharedbyMSC,HLR,BSCandOMC;Twoofthenetworkcanhail,canmakefulluseofcomputerroom,transmissionandpowersupply,andairconditioningandotherfacilities,saveConstructioninvestmentandmaintenancecost;Althoughthe900MHzand1800MHzwavespropagationcharacteristicsofendlessandsame,butGSM1800andGSM900radiofrequencyplanningmethodsandtoolsbutbasicsame;GSM1800wirelesscoveragesmall,thesmallradius,coveringthesameareasthatneedtobemorestations,thusincreasingthenetworkcapacityperunitarea;Becausebothprincipleandsystemstructureissame,cansavethenetworkoperationmaintenanceandtrainingofpersonnelcosts.Intheprocessofnetworkconstructionexperiments,shouldpayattentiontothefollowingproblems:theconstructionofthesystemshouldbeexcitedtodifferentiatebetweenaccordingtospecificsituation,shouldsticktosolvetrafficpopulatedareasoffocusforpolicy,andtomakefulluseoftheexistingGSM900systemequipment,willbothorganicunion.Fortrafficsmallerareas,double-frequencynetworkcanbeSharedbyMSC,BSCequipment,andevenusbasestation,socanflexibleconfigurationnetwork,setasideforfutureexpansionisnegotiable.Forarelativelylargeareatraffic,shouldconsiderwillbothswitchessetapart.ItcanreducethepressureoftheoriginalGSM900switches,andreducetheimplementationGSM1800systemengineeringtotheinfluenceoftheGSM900whensystem.ofthebasestationshouldasfaraspossible,inordertosaveconstructioninvestmentandmaintenancecosts.shouldreducedouble-frequencyswitch,asfaraspossibleletGSM900systemguaranteecoverage,andGSM1800systemfullyabsorbedbytelephone.Thiscanbeadjustedbybetweentwosystemsswitchingalgorithmandswitchinglevelthreshold,andrealizingmethod.inthearrangementshouldasfaraspossiblewhenchoosehighgainantenna,lowlossfeeder.inGSMPhase2becauseofAsupplementtomanyperforman