A communication system comprising: a plurality of integrative radio base stations, each of which being adapted to hold station data including information on cells managed by the station and information on cells adjacent thereto, determine whether the station holds information on an adjacent cell that is a destination of a mobile terminal and information that is required at the time of handover of the mobile terminal, acquire the information on the cell if the station does not hold the information on the cell, and relay communication between the mobile terminal and a core network; and a station data management device which is adapted to manage station data for each integrative radio base station, perform an authentication process in accordance with a request from the integrative radio base station, provide station data required for a processing operation by the integrative radio base station if the integrative radio base station which has made the request for authentication is permitted to be connected to a network, and send back the information on the cell to the integrative radio base station that is the source of the request if the integrative radio base station requests the station data management device to send the information on the cell, wherein said integrative radio base station is adapted to request said station data management device to carry out authentication when connecting to a radio access network, wherein said integrative radio base station is adapted to determine whether handover of the mobile terminal is required based on a received report of a measurement result and to specify a cell of destination of the mobile terminal, and wherein, if said integrative radio base station does not hold information on the specified cell, said integrative radio base station is adapted to request the station data management device to send only the information on the specified cell. a plurality of integrative radio base stations, each of which being adapted to hold station data including information on cells managed by the station and information on cells adjacent thereto, determine whether the station holds information on an adjacent cell that is a destination of a mobile terminal and information that is required at the time of handover of the mobile terminal, acquire the information on the cell if the station does not hold the information on the cell, and relay communication between the mobile terminal and a core network; and a station data management device which is adapted to manage station data for each integrative radio base station, perform an authentication process in accordance with a request from the integrative radio base station, provide station data required for a processing operation by the integrative radio base station if the integrative radio base station which has made the request for authentication is permitted to be connected to a network, and send back the information on the cell to the integrative radio base station that is the source of the request if the integrative radio base station requests the station data management device to send the information on the cell, wherein said integrative radio base station is adapted to request said station data management device to carry out authentication when connecting to a radio access network, wherein said integrative radio base station is adapted to determine whether handover of the mobile terminal is required based on a received report of a measurement result and to specify a cell of destination of the mobile terminal, and wherein, if said integrative radio base station does not hold information on the specified cell, said integrative radio base station is adapted to request the station data management device to send only the information on the specified cell.