【正文】 ing4) 覆蓋預(yù)測(cè)與規(guī)劃Coverage prediction and planning5) 頻率規(guī)劃與干擾預(yù)測(cè)Frequency planning and interference prediction6) 工程的實(shí)施Construction 一個(gè)完整的網(wǎng)規(guī)工作首先要進(jìn)行系統(tǒng)需求調(diào)查分析，采集前方城市各個(gè)方面的數(shù)據(jù)，包括地形地貌，城市發(fā)展情況，現(xiàn)有網(wǎng)絡(luò)情況等等。The parameters of uplink and downlink should be considered in the link budget. Please list the factors that will affect the path loss. 答：人體損耗、建筑物損耗、饋線及其他損耗、雙工器損耗、分路器以及合路器的損耗。Set RXLEVMIN1800M of the adjacent cell a little larger than that of 900M, so as to ensure that the 1800M cell is the candidate cell that will be handed over to by precedence. Set the PBGT threshold of the 1800M cell a little smaller than that of the 900M cell, so that the 1800M cell will be handed over to by precedence when PBGT handover occurs. 這樣就可以實(shí)現(xiàn)話務(wù)的分擔(dān)。所以我們盡量要使網(wǎng)絡(luò)用戶占用到1800M上面來。For the call dropping due to handover, check whether the network parameters are set unreasonably, such as wrong definition of adjacent cell and unreasonable setting of threshold. 2. 請(qǐng)簡(jiǎn)要的談?wù)勲p頻網(wǎng)絡(luò)的話務(wù)分擔(dān)如何實(shí)現(xiàn)。增大基站的覆蓋范圍（如提高基站的最大發(fā)射功率或者改變天線的方位角、傾角和掛高等）。如果從報(bào)告中可以得出本小區(qū)受到干擾的結(jié)論，那么，下面要作的工作是檢查頻率規(guī)劃的方案，看看頻率規(guī)劃中是否錯(cuò)誤地將相鄰小區(qū)的頻點(diǎn)設(shè)為本小區(qū)的同頻或鄰頻，或者在實(shí)際的頻率配置操作中有所失誤。比如，如果此小區(qū)的TCH指派成功率也較低的話，我們將考慮是否此小區(qū)的收發(fā)信機(jī)有什么問題或者天線未能正確安裝(兩個(gè)小區(qū)的天線裝反了)，某段饋線或接頭處未能完成良好的屏蔽等。包括檢查掉話現(xiàn)象增多時(shí)的時(shí)間，以及設(shè)備的運(yùn)行中的告警和通知消息報(bào)告。The measures for reducing dropped call rate should be based on the actual cases. Generally, the areas that suffer call dropping can be identified using the dropped call statistics report for each period of time for each cell provided by the OMCR operation amp。硬件故障，天饋線原因引起掉話。切換參數(shù)設(shè)置錯(cuò)誤或者不良都可能引起掉話。同頻干擾或者是鄰頻干擾都可能引起掉話。孤島站比較明顯。The antenna feeder has a too large standing wave ratio, which reduces the transmitter power. 1. 掉話率在移動(dòng)通信網(wǎng)中是一項(xiàng)非常重要的指標(biāo)，掉話率的高低在一定程度上體現(xiàn)了移動(dòng)通信網(wǎng)絡(luò)的優(yōu)劣。周期位置更新的頻度是由網(wǎng)絡(luò)控制的，周期長度由參數(shù)T3212確定。尋呼區(qū)的定義、本系統(tǒng)的用戶數(shù)量等。 and makes the uplink signal of this point that arrives the base station to be larger than the receiver sensitivity of base station after deducting the loss and system allowance. It aims to make sure that the system is designed to satisfy the coverage requirements, reduce the possible unidirectional munication due to imbalanced uplink/downlink, and increase the effective wireless call pletion rate. In other words, an accurate uplink/downlink power balance budget is used to ensure two directions have the same traffic and munication quality. It is also related to the actual coverage of a cell.6. 交換機(jī)局?jǐn)?shù)據(jù)檢查主要包括那些項(xiàng)目：Please describe the items that should be checked for the exchange data of switch. 答：主要包括本系統(tǒng)內(nèi)處理機(jī)的配置、中繼群、中繼電路的定義及配置、對(duì)端局類型、所采用的信令類型等。也就是準(zhǔn)確的上下行鏈路功率平衡預(yù)算是保證在兩個(gè)方向上具有同等的話務(wù)量和通信質(zhì)量的手段，也關(guān)系到小區(qū)的實(shí)際覆蓋范圍。目的是保證設(shè)計(jì)系統(tǒng)滿足覆蓋要求。頻率分集實(shí)際上是提高了網(wǎng)絡(luò)的覆蓋范圍，干擾分集則提高了網(wǎng)絡(luò)的容量。其中控制信道用于攜載信令或同步數(shù)據(jù)，包括三類控制信道：廣播信道、公共控制信道和專用控制信道。無線子系統(tǒng)的物理信道支撐著邏輯信道。常用的頻率復(fù)用方式有7*4*3*1*3。Divide the sum of the two numbers by 8 to obtain the carrier frequencies required for the cell of the base station. 3) 根據(jù)覆蓋確定需要的BTS數(shù)，根據(jù)用戶容量確定需要的BTS數(shù)量，兩者之間取大者Determine the number of required BTSs according to the coverage, and determine the number of required BTSs according to the subscriber capacity. The larger one of the two numbers should be used. 簡(jiǎn)答題Questions1. 頻率復(fù)用的定義，常用的幾種頻率復(fù)用方式？Describe the definition of frequency reuse and list the several mon frequency reuse modes. 答：頻率復(fù)用就是指在數(shù)字蜂窩系統(tǒng)中重復(fù)使用相同的頻率，一般把有限的頻率分成若干組，依次形成一簇頻率分配給相鄰小區(qū)使用。 查愛爾蘭B表，估算所需的話音信道數(shù)和控制信道數(shù)；Check the Erlang B table and estimate the number of voice channels and the number of control channels. 216。 用規(guī)劃區(qū)面積除以基站最小覆蓋面積（估算）得到基站總數(shù)；Divide the area of planned region by the minimum coverage (estimated) of the base station to get the total of base stations. 216。 由話務(wù)模型、愛爾蘭B表，得到話音信道數(shù)、控制信道數(shù)和容量。 由頻率資源及頻率復(fù)用方式，估算每個(gè)基站最大站型和容量；Estimate the largest station type and capacity based on the frequency resources and frequency reuse pattern. 216。Install the antenna to another place or change the offset of antenna direction. 3. 請(qǐng)簡(jiǎn)述容量規(guī)劃過程。Discontinuous transmission (DTX). 降低基站天線高度。Answer: Increase the distance between two cells with the same channel. 降低基站和MS的發(fā)射功率電平來避免同頻干擾。Answer: t3212 is the periodic location update time parameter that is used to force the mobile station to initiate a location update request to the network after this timer expires. The smaller value of T3212 indicates the better overall performance of the network. However, the frequent location update has two side effects. One is the signaling flow of the network will increase substantially, so the utilization of radio resources decreases. In the worst case, this will negatively affect the processing capability of MSC\BSC\BTS. The other is the mobile station has a rapidly increased power consumption, so the standby time of the mobile station in this system reduced greatly. Also note that T3212 must be less than the implicit shutdown time set within NSS, so as to prevent the mobile station from failing to connect to the network because it does not conduct location update timely. 2. 請(qǐng)簡(jiǎn)述幾種消除同頻道干擾的方法。在嚴(yán)重時(shí)將影響MSC\BSC\BTS的處理能力；另一方面將是移動(dòng)臺(tái)的耗電量急劇增加，使該系統(tǒng)中移動(dòng)臺(tái)的待機(jī)時(shí)間大大縮短。Please describe the precautions on setting of T3212 parameter. 答：t3212是周期性位置更新時(shí)間參數(shù)，用來強(qiáng)制移動(dòng)臺(tái)在該定時(shí)器逾時(shí)后自動(dòng)向網(wǎng)絡(luò)發(fā)起位置更新請(qǐng)求。例如，在正常供電時(shí)，系統(tǒng)能根據(jù)話務(wù)量的下降適當(dāng)關(guān)閉部分載頻模塊的電源。4路分集功能和DPCT同時(shí)使用，可使基站實(shí)現(xiàn)超遠(yuǎn)覆蓋。 支持DPCT（Dual Power Combining Transmission）方式的擴(kuò)展覆蓋BTS的雙密度載頻模塊中的兩個(gè)發(fā)信機(jī)實(shí)現(xiàn)相干聯(lián)合DPCT。主要完成GSM系統(tǒng)中兩路載波的無線信道的控制和處理、無線信道數(shù)據(jù)的發(fā)送與接收、基帶信號(hào)在無線載波上的調(diào)制和解調(diào)、無線載波的發(fā)送與接收等功能。 雙載波216。提高帶寬利用率，降低CAPEX。由于信號(hào)通過更多的路徑到達(dá)收發(fā)信機(jī)，因此，此功能可以增強(qiáng)上行鏈路預(yù)算，即提高基站的接收靈敏度。增強(qiáng)基站上行鏈路的接收性能的同時(shí)，還可降低MS的發(fā)射功率，4路分集功能和延時(shí)發(fā)射分集同時(shí)使用，可使基站實(shí)現(xiàn)超遠(yuǎn)覆蓋。兩個(gè)發(fā)信機(jī)在短時(shí)延內(nèi)發(fā)射相同信號(hào)，兩個(gè)發(fā)信機(jī)當(dāng)作一個(gè)“虛擬發(fā)信機(jī)”來使用，使下行信號(hào)增強(qiáng)，可以獲得3dB的下行增益，從而提高了覆蓋范圍，能夠?qū)崿F(xiàn)20%（甚至30%）以上的增強(qiáng)覆蓋。IRC分集接收方式，可以提高接收機(jī)的上行靈敏度指標(biāo)，增大基站上行的覆蓋范圍。支持同一站點(diǎn)54個(gè)載頻擴(kuò)展，一個(gè)站點(diǎn)支持S18/18/18的擴(kuò)展。 （4）請(qǐng)V3宏基站產(chǎn)品相對(duì)比V2宏基站產(chǎn)品而言具有的優(yōu)勢(shì)？ANS：V3 設(shè)備是公司新開發(fā)的產(chǎn)品，相對(duì)于V2產(chǎn)品有了很大的改進(jìn)。而如果網(wǎng)絡(luò)側(cè)新的下行數(shù)據(jù)到來時(shí)，T3192還未超時(shí)，則網(wǎng)絡(luò)可以直接發(fā)送“分組下行指配”消息，來建立一個(gè)新的下行TBF，縮短TBF的建立時(shí)間。216。 216。在TBF釋放階段，如果MS處于ready狀態(tài)并且收到上行指配，MS將立即響應(yīng)該命令；如果在TBF釋放階段沒有收到上行指配，MS將進(jìn)入分組空閑模式。T3192代表的時(shí)間長度必須小于網(wǎng)絡(luò)側(cè)下行TBF的保護(hù)時(shí)間T3193，以確保MS在同一時(shí)刻TFI的唯一。手機(jī)在T3192定時(shí)器保護(hù)期內(nèi)，若收到網(wǎng)絡(luò)側(cè)來的PACKET DOWNLINK ASSIGNMENT消息或PACKET TIMESLOT RECONFIGURE消息，則T3192定時(shí)器停止，并轉(zhuǎn)入分組傳輸態(tài)。這時(shí)手機(jī)啟動(dòng)T3192定時(shí)器。在分組下行傳輸過程中，若待發(fā)RLC數(shù)據(jù)塊是最后一下行數(shù)據(jù) 塊，網(wǎng)絡(luò)將通過發(fā)送一個(gè)最后塊標(biāo)識(shí)（FBI