and the maximum possible values for the power. Within this set is also included the size of steps for increasing and decreasing the power. Averaging Before being compared with a certain threshold, quality and level values are averaged in order to reduce the ping-pong phenomenon. In fact, quality and level samples may vary much of the time. This is why averaging is used to make the variation curve smoother. Two parameters handle the averaging process. One is the 'window size' which gives the number of consecutive level or quality samples that are averaged. The second is 'weighting', which is the factor used to increase the importance of the last sample. A weighting greater than 1 is multiplied by the last sample before the series of window size values are averaged. Decision Each averaged value is compared to either a level or a quality threshold. When a comparison of Px with Nx fulfills the criteria of being greater than the upper limit or smaller than the lower limit, the power control mechanism is launched. Radio Network Optimisation Signal Averaging Process Phase 2 Phase 1 Level Averaged Threshold Figure 2.72 Signal averaging process and handover decision making Handover Control Handover control parameters handle the thresholds for activating the algorithm and the averaging mech- anisms. Handover control parameters are also classified into four groups. Enablability As a power control algorithm, handover control can be either enabled or disabled. From the perspective of the parameter, an 'enable handover' indicator exists for each type. The following list mentions only a Intrahandover due to interference in the uplink and downlink Power budget handover MS distance process SDCCH handover Umbrella handover Periodicity This category of parameters rules the periods when various handover events occur. One parameter, expressed in seconds, defines the minimum interval between handover requests. Another fixes the same indicator between unsuccessful attempts. 'Handover period' parameters set the minimum allowed time betw