A wireless communication system having a plurality of wireless base stations (BSs), and a second BS included under at least one of a first BS among the plurality of BSs and usable by a specified mobile station, the wireless communication system includes registering first identifiers as identifiers of the first BS and a second identifier as an identifier of the second BS in the specified mobile station in advance. The wireless communication system includes transmitting first information to the second BS when an identifier of a present cell is other than the first and second identifiers, and transmitting second information to the second BS when the identifier of the present cell is the first or second identifier, and controlling an operation of the second BS based on the received first or second information.