Patent ID: 8238273

Claim:
A communication system, comprising: a transmitter, including a plurality of transmission antennas that transmit a transmission data stream grouped by 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 perform retransmission processing for a grouped bit combination; and a receiver, including a plurality of reception antennas that receive a signal sent from the transmission antenna of said transmitter; and a reception processor that performs retransmission combination processing for each of the groups by combining likelihood calculated with respect to a reception signal received by the reception antennas for each of the groups, wherein a combination of data bits retransmitted from a part or all of the plurality of transmission antennas at the same time is the same as a combination of data bits having already been transmitted from a part or all of the plurality of transmission antennas at the same time; the combination of data bits retransmitted from a part or all of the plurality of transmission antennas at the same time includes at least one of data bits which are not object of the retransmission; and the retransmission combination processing is performed with the product or the sum of logarithm likelihood of the probability of specific combinations of grouped data bits that are the object of the retransmission and grouped data bits that are not the object of the retransmission wherein the logarithm likelihood of the probability of the specific combinations of grouped data bits used for combination processing meet optimized value criteria.