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team and between front line personneland back side support personnel.Project closureThe last phase of the projectincluded outputting the networkoptimization report for each servicearea to capture experience of, andlessons learned from the project. At theend of the project, the Erl drop ratioof the optimized service area had beengreatly increased, realizing the initialobjectives of the project.Network optimization servicesThe CDMA network optimizationproject was focused on improving theErl drop ratio results. In cases wherean important network performanceindicator is focused, the “TOP10”analysis method can improve the workefficiency. The Erl drop ratio is anapproach to understand the networkperformance, and it is computed usingthe following formula: the busy hourErl drop ratio (in minutes) = Busy hourtraffic load (Erl) (without handover)×60/total number of dropped calls in atraffic channel.It is obvious that to improve the Erldrop ratio, it is necessary to reducethe number of dropped calls. Theproject team began the optimizationprocess by selecting the top 10 basestations that had the largest numbersof dropped calls; finding out reasonsof dropped calls and poor qualityservice by analyzing the equipment,network, and resource utilization; andoffered targeted technical assistanceto enhance the overall performance ofbase station controllers (BSC).The engineers adopted the followingtechnical methods to reduce droppedcalls at a certain base station:● Single-station check and preoptimizationtestThe team performed single-stationcheck on most new BTSs as wellas the old BTS that had highdropped call rates throughanalyzing drive testdata and backgroundstatistics data. SomeBTSs were foundto be improperlyi n s t a l l e d .I n f o r m a t i o ncollected at thes i t e s a r e u s e f u lfor the future RFoptimization.● Statistical analysis ontest data and backgrounddataDespite heavy workload and tenseschedule, the team members finishedanalyzing the drive test data at anearly time and made a correspondingnetwork optimization plan. Thetest data and background statisticsdata acquired after implementingnetwork optimization, proved that theoptimization measures were effective.● RF optimizationThe RF optimization includesadjusting antenna pointing and height.● Wireless parameter optimizationA f t e r c h e c k i n g t h e w i r e l e s sparameters of all BTSs, the teamoptimized the wireless parameters ofthe BTSs that had high dropped callrates.With three-month effort, theGuizhou CDMA network optimizationproject had made remarkable progress.Take the Guiyang service area as anexample, its busy hour Erl drop ratiohad been greatly improved. The busyhour Erl drop ratio ofBSC0 hadi n c r e a s e dfrom 127 minutes to 172 minutesafter optimization, which not onlymet, but exceeded Guiyang Unicom’sexpectation (160 minutes). Similarly,the busy hour Erl drop ratio of BSC1had increased from 90 minutes to 132minutes.By applying the PMBOK theory,the project team strengthened theproject management which includesclarifying project goals, specifyinghow goals are achieved, along withproject control. With a focus on aseries of project-specific factors(time, scope, labor, quality, cost,risk, and communications), thenetwork optimization project cameto a successful conclusion within thespecified timeframe.ZTE TECHNOLOGIES 25