The present method groups a transmission data stream, taking a combination of data bits to be transmitted from a part or all of the plurality of transmission antennas at the same time as one group; and performs transmission processing, including at least either of bit repetition processing or retransmission processing by the unit of the group (bit combination). As a result, in MIMO communication, etc., it is possible to suppress deterioration of reception characteristic due to vanishing of correlation among bits transmitted at the same time.