la 27.70% SDCCH_RADIO_FAIL /c1003 166 ( 2.52%) SDCCH_A_IF_FAIL_CALL /c1078 0 ( 0.00%) SDCCH_ABIS_FAIL_CALL /c1075 1658 ( 25.18%) SDCCH_USER_ACT /c1037 0 ( 0.00%) SDCCH_BCSU_RESET /c1038 0 ( 0.00%) SDCCH_NETW_ACT /c1039 0 ( 0.00%) SDCCH_BTS_FAIL /c1036 0 ( 0.00%) SDCCH_LAPD_FAIL /c1035 0 ( 0.00%) SDCCH_RF_OLD_HO (HO drop) /c1004 0 ( 0.00%) SDCCH_ABIS_FAIL_OLD.... (HO drop) /c1076 0 ( 0.00%) SDCCH_A_IF_FAIL_OLD... (HO drop) /c1079 0 ( 0.00%) Figure 2.18 Example of area-level KPI statistics from the NMS RADIO NETWORK OPTIMISATION 2.5.4 Network Performance Assessment The performance indicators are listed below: amount of traffic and blocking resource availability and access handovers (same cell/adjacent cell, success and failure) receiver level and quality power control. Coverage Drive test results will give the penetration level of signals in different regions of the network. These results can then be compared with the plans made before the network launch. In urban areas, coverage is generally found to be less at the farthest parts of the network, in the areas behind high buildings and inside buildings. These issues become serious when important areas and buildings are not having the desired level of signal even when care has been taken during the network planning phase. This leads to an immediate scrutiny of the antenna locations, heights and tilt. The problems are usually sorted out by moving the antenna locations and altering the tilting of the antennas. If optimisation is being done after a long time, new sites can also be added. Coverage also becomes critical in rural areas, where the capacity of the cell sites is already low. Populated areas and highways usually constitute the regions that should have the desired level of coverage. A factor that may lower the signal level could be propagation conditions, SO study of link budget calculations along with the terrain profile becomes a critical part of the rural optimisation. For highway coverage, additions of new sites may be one of the solutions. Capacity Data co