A frame synchronizing unit of a slave base station synchronizes its own frame with a frame of the master base station, reception control slot setting control unit sets, as a reception control slot, a predetermined reception slot in its own frame matching in timing with a reception control slot in the frame of the master base station. A reception level obtaining unit of each of the base stations obtains a reception level of the reception control slot thus set when a link channel establishment request message is received in the set reception control slot. A traffic channel allocation control unit allocates a traffic channel with respect to a mobile station transmitting the link channel establishment request message to predetermined transmission and reception slots in the frame according to a traffic channel allocation instruction.