 that place. Adjacent sites are continuously added and/or deleted. The add/delete task can be automated using of Man-Machine Language (MML) in order to minimise the risk of human error. MML is a text based command language with a standardised structure, designed to facilitate direct user control of a system through a user interface function. An adjacency network is also used to monitor after BTS or BSC re-hosting. In fact, the network may require some reallocation of sites to new BSCs with a new LAC. Here, close coordination should be done with the MSC operation team in order to update the database (CI and LAC) at the BSC and MSC levels simultaneously. For instance, a bad adjacency declaration can cause a cell not to take any incoming handovers! This generally happens when LAC, CI, BCCH, BSIC_NCC or BSIC_BCC are false in the adjacent database. An alarm may indeed exist, which indicates a false declaration of target cell parameters in the source cell adjacency table. Such an anomaly has as a direct impact 100 % failure of outgoing handovers between those two cells. Therefore, at any change on a cell, attention should also be paid to this cell's incoming adjacency declarations. Two elements to consider in optimising an adjacency network are the statistical aspect and the geo- graphical aspect. As explained before, a subscriber's voice activity generates the necessary statistics used to measure the performance of the network. For handover and adjacency behaviour, it is possible to collect the number of handovers and the percentage of failure between each pair of cells in both directions over a period of time. Considering one source cell, by sorting the outgoing handover attempts in decreasing order, it is possible to calculate which relations are less useful for this cell. The operation is, however, not that simple. Before deciding to delete an adjacency, the opposite case should be considered to see whether the weight of this relation is not important from the target cell to the source cell. Consider an example to 