中級培訓(xùn)第二模塊之二頻率規(guī)劃

1、中級培訓(xùn)第二模塊之二頻率規(guī)劃中國移動通信集團河南有限公司網(wǎng)優(yōu)專家小組工作頻段 我國陸地公用蜂窩數(shù)字移動通信網(wǎng)GSM通信系統(tǒng)采用900MHz頻段： 890915（移動臺發(fā)、基站收） 935960（基站發(fā)、移動臺收） 隨著業(yè)務(wù)的發(fā)展，可視需要向下擴展，或向1.8GHz頻段的DCSI800過渡，即1800MHz頻段： 17101785（移動臺發(fā)、基站收） 18051880（基站發(fā)、移動臺收） 工作頻段 中國移動公司：890909MH（上行），930954MHz（下行），共19M帶寬，95個頻道，頻道號為195。中國聯(lián)通公司：909915MH（上行），954960MHz（下行），共6M帶寬，29個頻道

2、，頻道號為96124。95號頻點做為兩個公司間的保護頻點不可使用。 工作頻段頻道間隔 相鄰兩頻道間隔為200kHz，每個頻道采用時分多址接入（TDMA）方式，分為8個時隙，即8個信道（全速率）。GSM采用半速率話音編碼后，每個頻道可容納16個半速率信道。為什么要頻率復(fù)用19MHz = 94 channels, 7 traffic timeslots gives 658users = Maximum only 658 simultaneous calls?!受限的頻段受限的頻段 Reuse frequencies as often as possible Increased capacity I

3、ncreased interferences頻率規(guī)劃的目標得到更高的頻點利用率。通過頻率規(guī)劃可分析出網(wǎng)絡(luò)性能，發(fā)現(xiàn)網(wǎng)絡(luò)存在的一些問題。降低網(wǎng)絡(luò)干擾。平衡干擾和容量。有限的頻段內(nèi)，盡可能增加網(wǎng)絡(luò)容量。如何增加網(wǎng)絡(luò)容量Signal =All useful signals carrierAll useless signalsinterference=under reference interference levelCo-channel interference, C/Ic = 9dBAdjacent (200kHz) interference, C/Ia1 = -9dBAdjacent (400k

4、Hz) interference, C/Ia2 = -41dBAdjacent (600kHz) interference, C/Ia3 = -49dBUseful signalNoise from environmentOther signalsFrequency Allocation頻率分配確定可用的頻點查找干擾源： CDMA 外部干擾 微波 直放站等不同層使用不同的頻率復(fù)用注意各層間的保護Three type of BCCH planning are availableDedicated BandCommon BandDedicated mixed BandBCCHTCHBCCH + T

5、CHBCCHTCHDedicated bandCommon bandDedicated mixed bandMultiple Reuse Pattern (MRP)136912151821safe planning(BCCH layer)normal planning(TCH macro layer)tight re-use planning (IUO layer)same frequencyin every cell(“spread spectrum”) 每層所使用的頻點數(shù)不同。 BCCH層使用最大的復(fù)用方式，即頻點最多。 第二層分配給第二塊載頻，頻點相對BCCH層要少。 隨著TRX數(shù)量的增

6、加，每組的復(fù)用度降低，頻點也變少。BCCHReuse 1512129TRX1TRX2TRX3Multiple Reuse Pattern (MRP)Multiple Reuse Pattern (MRP) Example of capacity increase with MRP Network with 300 cells Bandwidth : 8MHz (40 radio channels) Single reuse of 12 Network capacity = 40/12*300 = 1000 TRX Multiple reuseBCCH layer : reuse of 14,

7、14 frequencies allocatedNormal TCH : reuse of 10, 20 frequencies allocatedTight TCH : reuse of 6, 6 frequencies allocatedNetwork capacity = (14/14) + (20/10) + (6/6)*300 = 1200TRXMultiple Reuse Pattern (MRP)跳頻MAIO-012-345-678BTS-3BTS-2BTS-1(sector 3)(sector 2)(sector 1)f1f2f3f4f5f6f7f8f9f10f11f12MAI

8、O offset036HSN 333RADIO RESOURCE MANAGEMENTRF Hopping (Site based MAIO allocation)TRX-1BCCHTRX-2TCHTRX-3TCHTRX-4TCHTRX-5BCCHTRX-6TCHTRX-7TCHTRX-8TCHTRX-9BCCHTRX-10TCHTRX-11TCHTRX-12TCHRADIO RESOURCE MANAGEMENTRF Hopping: Flexible MAIO Management (Optional)MaioStep 1.62UnderlayMaioStep1.62ParametersV

9、alueFrequency Allocation PrincipalThere should be no co-channel frequency bands in one BTS. 同小區(qū)不能同頻。The frequency separation in the same cell should be at least 400KHz,e.g. BCCH=40, TCH1=42, TCH3=44 同小區(qū)的頻率間隔最少400K。Different layers can have different frequency reuse ratio 不同層使用不同的復(fù)用率。There shall be a

10、 guard channel between different frequency groups 不同頻率組間有一個保護頻點。In consideration of the antenna height and the complicated spreading environment, adjacent BSs should not stand face-to-face (or oppose diagonally) with co-channel frequency. 面對面的相鄰小區(qū)不可以同頻。Pay close attention to co-channel reuse, avoidi

11、ng the situation that has same BCCH and same BSIC in nearby areas. 相鄰小區(qū)不可同BCCH同BSIC。Frequency AllocationFrequency Allocation Mapinfo Planning Tool (MIPT) can be used to check co-channel and adjacent channel frequency. MIPT - Frequency Search It can be used together with BSIC or independently Red rep

12、resent the frequency selected Eg. 80 Green frequency represents (channel 1) Eg. 79 Blue frequency represents (channel + 1) Eg. 81Frequency Allocation MIPT - Find Neighbors. Select “Check Co-Neighbors BCCH” Neighbors having same BCCH is listed in message box. A Red dotted line is draw from “Parent ce

13、ll” to “Neighbor cell” Check if these pairs of cells can cause interference to each other.Frequency Allocation鄰區(qū)規(guī)劃1、在地圖上看周圍的基站周圍的地形、地貌、阻擋物2、檢查基站信息 看站高、方向角、傾角3、小區(qū)覆蓋的預(yù)測，查看交迭覆蓋情況Adjacency Planning同站的其它扇區(qū)必須做成鄰區(qū)。第一圈須做鄰區(qū)，第二圈根據(jù)情況考慮。通常相鄰小區(qū)是要做成雙向的，A做B，那么B也要做A。相鄰小區(qū)最多做32個，如果要加入新的鄰區(qū)，那么就要先刪除一個。相鄰小區(qū)不要做的太多，這樣手機就有更

14、充足的時間來掃描鄰區(qū)，使得測試報告的結(jié)果更準確，從而使切換更準確。規(guī)劃原則Mapinfo Planning Tool (MIPT) can be used to check neighbor cells on map. Theres a button “Click Find Neighbor” on the toolbar.RED is the serving cell that you want to find its neighbor.Yellow is the neighbors of the serving cell.Gray is not the neighbors of the s

15、erving cell.Neighbors can be added/deleted from the database using MIPT - Edit database. Demonstration in Mapinfo.Adjacency PlanningAdjacency PlanningCheck unnecessary adjacenciesNetwork Doctor report 153 Adjacencies having high HO failure ratioIf HO attempt is small between pairs of cells, after cr

16、oss-checking on Map, this neighbor pairs can be removed.Adjacency PlanningFind missing adjacent cellsNetwork Doctor report 72 Defined, Undefined and used adjacencies of a cellIf number of samples is big, after cross-checking on Map, the neighbor pairs can be added.Adjacency PlanningAudit adjacent pa

17、rametersAdjacency Discrepancies ND060錯誤鄰區(qū)fAAdj listfBAdj listfBAdj listfAAdj listBSCNMSCell ACell BmismatchAdjacency PlanningCell ACell BFind one-way neighborsNon Symmetrical adjacency ND061單向鄰區(qū)cell B is neighbour of Cell Acell A is not neighbour of Cell BAdjacency PlanningCell A(10)Cell B(9,10 or 1

18、1)Frequency check of adjacent cellsAdjacent cells with same or adjacent frequency ND062相鄰小區(qū)中有同，鄰頻 cell A has carrier 10cell B has carrier 9, 10 or 11Adjacency PlanningCheck redundant adjacenciesAdjacencies to Non-existing Cells ND065不存在鄰區(qū)Cell B is deleted but incoming adjacencieswere not removedCell

19、 C is not known in OMC Area 1 databaseCell ACell COMC 1OMC 2Cell BBSC 1BSC 2Adjacency PlanningBSIC規(guī)劃在地圖上規(guī)劃BSIC相對麻煩。由于現(xiàn)在中國移動BSIC的分配空間較大，同一BCCH，就可以有7*8=56種不同的BISC，因此，要想把同BCCH同BSIC的兩個基站隔離較遠的距離，是很容量的。我們可以在EXCEL中，把經(jīng)緯度排度，再通過篩選相同的BCCH小區(qū)，分配不同的BSIC。BSIC規(guī)劃檢查頻率檢查及修改 首先，要在MAPINFO中劃分出若干區(qū)域，在每一區(qū)域中將1-94個頻點利用MIPT的FR

20、EQ SEARCH工具逐一顯示出來，利用視覺觀察的方法來檢查同鄰頻，并將有問題的頻點及時修改。值得注意的一點是劃分區(qū)域時，每兩區(qū)域應(yīng)適當?shù)闹丿B一部分，以免疏忽了兩塊的交迭部分。劃分的每一區(qū)域越小，檢查的效果越好，具體可視時間安排情況而定。其次，由于目前所使用的MAPINFO只是平面圖，而無線信號的傳播與地形、建筑物、基站的高度、下傾角等因素有著非常密切的關(guān)系，因此在平面圖上看似不大相關(guān)的兩個站也許會有很多的切換，所以另一種頻點檢查方法，就是利用相鄰小區(qū)數(shù)據(jù)，通過制作EXCEL的宏命令，對照切換報告來做更進一步的檢查。這也是前面強調(diào)的及時將相鄰小區(qū)數(shù)據(jù)導(dǎo)入現(xiàn)網(wǎng)的原因。 Heavily loaded frequenciesFrequency Allocation Less loaded frequenciesFrequency Allocation頻率規(guī)劃經(jīng)驗總結(jié)頻率規(guī)劃前的準備工作：是非常關(guān)鍵的，時間人員的安排、基站信息的準確 性直接影響到頻率規(guī)劃的進度和質(zhì)量。頻率規(guī)劃最好選在網(wǎng)絡(luò)變化小的時期。相互協(xié)作、互相溝通：頻率規(guī)劃最好要有2 3人配合完成，1個人的思維往往會受到局限. 在頻率規(guī)劃的過 程中，網(wǎng)絡(luò)由于擴容、改型、 新建站等，也處于不斷的變化之中，作為規(guī)