A device and a process which enable use of transmission diversity in transmission to a receiving station when wirelessly relaying wireless signals from a transmitting station to the receiving station. A reception antenna RA in a wireless relay device (RS) receives from the transmitting station such as a base station (BS) a signal in which data signals are respectively allocated to carriers at adjacent radio frequencies. The wireless relay device performs space frequency block coding (SFBC) of the received signal. Then, the wireless relay device transmits SFBC-encoded signals through two transmission antennas SA0 and SA1 to the receiving station such as a mobile station (MS).