Provided are a method and an apparatus for transmission and reception based on hybrid automatic repeat request in a communication system. A first communication node includes a coherent channel region (CCR) mapper configured to determine W representative soft bit values for each CCR on the basis of X original soft bit values of signals and determine a sign sequence of the X original soft bit values, and a CCR demapper configured to restore X soft bit values for each CCR using W representative soft bit values and a sign sequence. Since the CCR mapper compresses soft bits using channel coherency, a hybrid automatic repeat request (HARQ) buffer size is reduced compared to that of an existing method. Therefore, performance of a communication system may be improved.