e 7.7 Cell breathing (decrease in coverage area with increase in subscribers) factor is 1 in a WCDMA radio network, but code planning needs to done accurately. As there are 512 sets of codes, it is recommended that the automatic code allocation technique be used rather than manual allocation as the latter may lead to errors, thereby degrading the quality. One concept that is important to understand at this point is cell breathing. The coverage area of a cell depends on the number of subscribers and their data rates. If the number of subscribers using the cell increases, the area covered by the cell decreases. As the load decreases, the area increases. This phenomenon is depicted in Figure 7.7. Another phenomenon that directly affects capacity and quality is soft capacity. Erlang B tables can be used for the capacity calculation based on hardware limitations. However, in WCDMA radio networks, as the capacity is limited by interference (on the air interface), it is described as soft capacity. The less the interference from neighbouring cells, the more the capacity increases. The concept of soft capacity is important for data users. More capacity leads to a better connection (i.e. lower blocking) for real-time data users. Soft capacity can be obtained in one cell only if the adjacent cells have a lower loading (or fewer subscribers in them). Uplink soft capacity is based on the total interference at the base station, which includes own-cell and other-cell interference. 7.6.2 Radio Resource Management For parameter planning in a WCDMA radio network, radio resource management (RRM) and mobility management (MM) should be understood. RRM and MM, as in GSM networks, consists of concepts such as the control of radio resources, admissions, power, han- dovers, etc. RRM is important from the perspective of air-interface resource utilisation, thereby offering optimum coverage and capacity and, above all, guaranteeing the quality of service. As seen in Figure 7.3, the radio resource control (RRC) layer has two main layers bene