ectors of two base stations (case 1 in Figure 7.6). A signal comes to the mobile from two 3G RADIO NETWORK PLANNING AND OPTIMISATION Softer HO (case 2) Site 1 Site2 Soft HOV (case 1) Figure 7.6 Handover in WCDMA radio network directions, but with the use of RAKE receivers the mobile antenna receives a combined signal. Another type of handover is called 'softer'; in this case, the mobile is connected to two different sectors of the same base stations (case 2 in Figure 7.6). Again, the mobile receives both the signals owing to the presence of RAKE receivers. In both the cases, as the mobile is using two different paths (interfaces) for communicating with the base station, two different codes are used SO that the mobile can recognise the different paths. There is not much difference in the downlink direction, but is a significant difference in the uplink direction for the two handovers. In the case of soft handover, the received signal is routed to the RNC from both the base stations so that the best RNC can take a decision on keeping the signal which is giving a better quality. As this decision-making process takes time (about 10-80ms). double air-interface capacity is used by a single mobile for one call. Hence, radio engineers have to take into account this process when capacity planning for the radio network. About 30% of the links witness soft handover, against 10% for softer handover. The measurements generally include received signal code power (signal power received on one code), signal power received within the channel bandwidth, and the ratio of the received bit energy to the thermal noise, E/No (see below). 7.5.8 Coverage Planning As mentioned above, coverage is an issue that is dependent upon the area to be covered, terrain type and the propagation conditions. Coverage should include all the regions such as dense urban, urban, rural, etc. As in GSM networks, all these factors have an impact on the distance that can be covered by a given cell (the cell range). But in contrast to GSM, capacity within a cel