BTS. Two separate parameters enable the activation or not of either of the two power control mechanisms. Generally, signal strength real values fluctuate greatly over time (see Figure 2.67). In order for either DL or UL power control to work, the idea of averaging is introduced. The mechanism of averaging is based on three parameters: signal level (L), window size (WS) and weighting (W). The samples of successive L measurements within WS are averaged with attribution of W to the last sample in order to produce one equivalent level averaged sample (LAS). Then the window is shifted in the time and the same calculation is repeated. When Px (probability number) values of LAS out of Nx (total number) fulfil the criterion of being bigger or smaller than the upper or lower thresholds respectfully, power control is launched. The bigger the window size, the smoother is the equivalent output power. Figure 2.68 shows the difference between the two different periods. In conclusion, power control has a direct impact on signal level. Since handover decisions take into account signal level, it can be said that there is a close interdependency between the power control and handover control mechanisms. Power control is, moreover, a feature that aims to reduce interference and thus influences many handover decisions. The idea is to reduce the power of the transmitter until the level is reached that is necessary and sufficient to the receiver to understand the signal. Practically speaking, if the MS is too close to the BTS, it asks it to reduce its power. In the power control mechanism, there is also a need for sampling and averaging the signal before any decision is taken. Power control can occur either in idle mode or connected mode. The PC algorithm has also a set of parameters, as mentioned earlier in the parameter tuning section. Handover and Adjacency Difference Each cell of the network should be operational intrinsically, but also integrated in the network and interoperational with other cells. Handover is the action of tran