Handover in sectorized radiocells

A base station apparatus measures the statistic of a reported known reference signal with receivable level from another base station, refers to the reported angle difference information and located base station information with respect to the known reference signal of another base station showing the receivable level in a predetermined period, detects a location of the cell with the known reference signal, and when it is determined that the cell is not appropriate for the cell for a handover, outputs an interference degree notification signal to the another base station of that cell. In addition, in the case where it is notified that interference to a certain cell is large by the interference degree notification signal, the notified base station controls to decrease an antenna directivity toward the direction to the certain cell based on the located base station information.