The CP inserter 182 inserts a cyclic prefix into the transmission signal input from the IFFT 180. The cyclic prefix may be, for example, a cyclic copy of a portion of subsequent symbols. Then, the CP inserter 182 outputs the transmission signal into which a cyclic prefix is inserted to the RF circuit 184.

The transmitting antenna 154 (158) is connected to the RF circuit 184 and used for transmission of a radio signal. The RF circuit 184 causes the transmitting antenna 154 (158) to transmit the transmission signal input from the CP inserter 182 as a radio signal after the transmission signal being DA (Digital to Analogue) converted, frequency converted, and amplified.

According to the first configuration example shown in FIG. 8A, the encoder 162, the interleaver 164, the mapper 178, the IFFT 180, the CP inserter 182, and the RF circuit 184 are shared between the first transmitting unit 152 and the second transmitting unit 156. Accordingly, it becomes possible to downsize hardware of the relay station 100 or to reduce manufacturing costs thereof.

The modulation and/or multiplexing method used by the relay station 100 for transmission of a radio signal can serially be switched for each time slot by the operation of the switch 166. That is, for example, the relay station 100 can transmit a radio signal by using the first modulation and/or multiplexing method in a first time slot (or a first resource block) and then transmit a radio signal by using the second modulation and/or multiplexing method in a second time slot (or a second resource block).

(Second Configuration Example of the Transmitting Circuit)