as not taking place at the time of measurement. Symptoms: low Ec/10 in the UE and Ec/10 on the scanner; normal RSCP in the UE and in the scanner; small number of scrambling codes in the active and monitored sets; high RSSI. Radio Network Optimisation Problem: external interference. Someone is transmitting on the WCDMA frequency band. The source of interference is to be investigated. Symptoms: plotting the individual scrambling codes RSCP shows that the cell has a strong RSCP beyond the first-trie neighbours; plotting the Ec/10 shows that the site has a large area with a poor Ec/10 outside its first-tier neighbours, or it has dominance in the area that it is not intended to be the dominant server. Problem: overshooting site. The antenna should be tilted to limit cell coverage within the first-tier neighbours on the intended dominance area. By tilting this type of site the performance of surrounding sites will improve. Symptoms: plotting the individual scrambling codes RSCP shows that the cell has a small coverage area; plotting the Ec/10 shows that the site has a poor Ec/10; it is not a dominant server in the area in which it is supposed to have been a serving cell. Problem: limited coverage. The antennas and hardware should be checked for problems. If the only terrain is limiting and there are only a few users in the dominance area of the cell, the cell could even be switched off to limit the interference. System Issues If the radio interface does not indicate any problems with RF conditions the problem is likely to be related to the UE, network or measurement system functionality. The L3 signalling messages before the dropped call should be analysed to find out if there were any messages sent that would indicate abnormal system behaviour. In the case where an L3 message indicating problem is found the signalling flow is analysed to find out details of the system problem (shown in Figure 2.96). In addition to L3 messages, the power control commands, the bitch error ratio (BER), the block error rate (BLER), and L2