A method by a terminal, method by a base station, a terminal, and a base station are provided. The method by the terminal includes transmitting two transport blocks; and if one of the two transport blocks is negatively acknowledged (NACKed) and a physical downlink control channel (PDCCH) including control information is not detected, adjusting retransmission for the NACKed transport block using a precoding index 0 and a number of layers corresponding to the NACKed transport block.