 and umbrella handovers. Priority In a lot of handover mechanisms, prioritisation is important in the selection of a target cell for handover. It is based on giving more priority to cells experiencing less traffic load. This issue is driven by three main parameters: a threshold in percentage starting from what a cell is considered as loaded; a load factor that gives in units the offset to apply to overloaded cells; a priority level that ranks primarily all of the adjacent cells. Radio Network Planning and Optimisation The algorithm is simple. The final priority to rank adjacent cells is equal to the primary priority decreased by the load factor for cells loaded with more than the load threshold. At the end, cells with a high traffic load have the lowest priority and handover is then commanded to cells with no load. Averaging Averaging is important to prevent repetitive handover attempts between two cells. Four parameters drive the process: Window size gives the number of measurements that should be averaged. Weight indicates the importance given to the last measurement in the averaging formula. Nx is the total number of averaged samples that are to be considered. Px is the required number among the Nx samples that should fulfil the criterion before a handover can be triggered. Thresholds Once the network performs averaging, it compares the Nx samples to a given threshold. Depending on the type of handover (quality, level or interference, for example), there is a special criterion that Px samples should meet before the handover is initiated. Level and interference thresholds are in the 'RXLEV' terms whereas the quality threshold is given as 'RXQUAL' values. Adjacency Parameters An adjacency is defined on a cell-to-cell basis. These are in fact parameters that define the behaviour of a couple of cells linked by an adjacency relationship. Adjacency Definition An adjacent parameter set is useless unless the two cells are declared as adjacents. In defining an adjacency between two cells, each direction can have its ow