A base station allocates downlink transmission powers to user equipments according to the reception qualities of the user equipments. The base station transmits a mixed data signal in which multiple data signals that are addressed to multiple user equipments and are not orthogonal to each other are mixed, and transmits multiple control signals to the multiple user equipments such that each user equipment can decode the data signal addressed to that user equipment using the control signal corresponding to that user equipment. Each control signal is scrambled using the identifier of the user equipment corresponding to that control signal. With a period longer than the transmission period for the control signal, the base station notifies the multiple user equipments of identifier information indicating multiple identifiers, and thus the user equipment can descramble a control signal for another user equipment to which an interference data signal with a higher transmission power is addressed.