Antenna GuidelineKeep standard azimuth 40/160/280Electrical tilt is the preferred tilting type, mechanical tilt should be avoided if possible. More than 8 degree need justification, Less than 2 degree tilt need justificationTo avoid unnecessary antenna adjustments, tilting shall be done in 2 degree steps for normal antennas 0, 2, 4, 6, 8 degreeAs high gain antennas are more critical for tilting for them 1 degree steps could be apply

Overshooting GuidelineOSS TA measurements are used for identification of general overshooting cases as the granularity is 550m only, DT confirmation is a must before physical adjustment

Capacity GuidelineMaximum TRX configuration for GSM 4 TRX and for DCS 8 TRXDCS is the main traffic layer and target is to bring as much traffic to DCS as possible. 3G share around 10% of voice traffic30% of HR can be accepted in cells with maximum configuration. More than 30% HR can only be a temporary solution to avoid blocking in the networkTraffic sharing between the layer and to neighbor cells without major impacts to coverage or performance has higher priority than new sites Also need to check 3G colo sites to share trafficPlanning 4 static PDCH for each cell (30% of TCH shall be defined as dynamic TCH/PDCH) for initial configuration, adjustment to traffic demand shall be apply based on traffic measurements

Uplink Interference GuidelineIdentification of Uplink Interferences by Idle Channel Measurements of the TRXMeasurements in Idle Band 3-5 >10% of samples indicates serious interference of the cellCDMA interference solution is installing filter, Inter modulation solution need to check hardware

Link Imbalance GuidelineLink imbalance between uplink and downlink case can be identified from the TRX measurementsDownlink issue if 30% of samples in Level 1&2Uplink issue if 30% of samples in Level 10&11Such link imbalance issues need hardware check

Summary Common RF issues

Correct setup of tool, test method, test time and test route are essential for reliable & comparable drive test results, all the setting should keep the same

Weak CoverageWeak coverage can only be judged from idle mode Rx_Lev measurements.Need to confirm if the cell had HW issues and confirm if coverage gap exist long time or short timeFor weak coverage near the site, need to check the real environment and antenna configuration (site audit report or sites audit)New site can be proposed in weak coverage area far away from current sites

Bad QualityBad RxQual values are 5, 6 and 7, if such values appear for a longer time period the network quality is bad and need improvementsBQ issues need to confirm no weak coverage problem firstNeed check BQ on BCCH or TCH and the serving cell and NB signal level Interferences on DCS TCH can only take place if the same sector from different sites are covering the same area (3*1 reuse pattern)Interference must be located and the interference signal from non serving cells need to be reduced by physical adjustment or increase signal level of serving cellSummary DT Issues

Handover IssueAll handover issues need to check the algorithm parameter setting firstHandover failure issue, need to check and improve the RF quality when handover happen. And need to check the target cell condition, like capacity or interference or HW issues. No handover issue, MS cannot handover to a suitable cell as algorithm defined, there is the need to check the reason like blocking of target cell, missing handover relation, bad quality and uplink problems of target cellPing-Pong handover, usually happened in no dominant server areas as identified during DT. There is the need to get a dominant server by improving coverage from one main cell and reduce signal of other cells. Or need to check HW issue like partial cross feeder. Summary DT Issues