A communication apparatus comprising: a communication section adapted to: receive an original signal from a sender; acquire data from the original signal and perform error detection on one or more pieces of the acquired data to determine whether data reception has succeeded; transmit information regarding a configuration of a retransmission signal for retransmitting information of the original signal whose demodulation has failed to the sender of the retransmission signal; retain the information regarding the configuration of the retransmission signal transmitted as retained information; receive the retransmission signal transmitted from the sender on a basis of the retained information; and a synthesis section adapted to perform information synthesis by using the original signal and the retransmission signal received by the communication section on a basis of the retained information, wherein: the information regarding the configuration of the retransmission signal includes information regarding data whose retransmission is requested; the information regarding data whose retransmission is requested includes information regarding an identifier of a first piece of the data, a bitmap identifying a second or succeeding pieces of the data and information regarding a length of the data relative to the identifier of the first piece of the data as a reference; and the information regarding the length of the data is repeated as many times as the number of pieces of data whose retransmission is requested. receive an original signal from a sender; acquire data from the original signal and perform error detection on one or more pieces of the acquired data to determine whether data reception has succeeded; transmit information regarding a configuration of a retransmission signal for retransmitting information of the original signal whose demodulation has failed to the sender of the retransmission signal; retain the information regarding the configuration of the retransmission signal transmitted as retained information; receive the retransmission signal transmitted from the sender on a basis of the retained information; and a synthesis section adapted to perform information synthesis by using the original signal and the retransmission signal received by the communication section on a basis of the retained information, wherein: the information regarding the configuration of the retransmission signal includes information regarding data whose retransmission is requested; the information regarding data whose retransmission is requested includes information regarding an identifier of a first piece of the data, a bitmap identifying a second or succeeding pieces of the data and information regarding a length of the data relative to the identifier of the first piece of the data as a reference; and the information regarding the length of the data is repeated as many times as the number of pieces of data whose retransmission is requested. the information regarding the configuration of the retransmission signal includes information regarding data whose retransmission is requested; the information regarding data whose retransmission is requested includes information regarding an identifier of a first piece of the data, a bitmap identifying a second or succeeding pieces of the data and information regarding a length of the data relative to the identifier of the first piece of the data as a reference; and the information regarding the length of the data is repeated as many times as the number of pieces of data whose retransmission is requested. <EOS>