illustrate this. Table 2.23 shows that for cell 40472, the relation with cell 40298 has the lowest priority and could be deleted without affecting the performance. However, the adjacency table of the target cell 40298 is considered, illustrated in Table 2.24, it can be seen that the relation with cell 40472 is important for cell 40298 and SO it is not advisable to delete this relation. An adjacency relation is generally symmetric. This means that if cell A is declared towards B auto- matically cell B will have to be declared towards A. This is why if the relation is important in either Radio Network Optimisation Table 2.23 Adjacency table of the source cell 40472 From_LAC From_CI HO=>Att HO=>Blck% HO=>Fail% HO<=Fail HO<=Blck% HO<=Att TO_CI TO_LAC 40472 15050 15804 40113 40472 40094 40472 40114 38 40472 40473 40472 40305 40472 40729 42 40472 49847 40472 40115 40472 40782 40472 49848 38 40472 40471 38 40472 40781 42 40472 40411 38 40472 40628 40472 40442 40472 40678 40472 40304 42 40472 40330 40472 40089 38 40472 54348 38 40472 40627 40472 49367 40472 40780 40472 40028 40472 40298 Table 2.24 Adjacency table of the target cell 40298 From. LAC From_CI HO=>Att HO=>Blck% HO=>Fail% HO<=Fail HO<=Blck% HO<=Att TO_CI TO_LAC 40298 40299 40298 40627 40298 40629 40298 40297 40298 40472 38 40298 40648 40298 40445 40298 40628 38 40298 40411 40298 40485 40298 40622 Radio Network Planning and Optimisation direction the declaration is kept in both ways. However, for optimisation reasons, sometimes the optimi- sation engineer decides to keep some relations asymmetric. This is the case when for special reasons a certain handover sequence needs to be forced. The idea is to declare adjacency from unwanted cells in the sequence towards the wanted cells in one direction. The aim is that if the mobile camps on an unwanted cell can still handover towards the cell supposed to cover the MS location and if the MS camps on the right cell, there is no room to let it handover towards an unwanted cell. The second criterion for adding/deleting un