Abstract: The invention relates to incremental redundancy operation, and a basic idea of the invention is to provide an extended acknowledgment feedback, for each of a number of data blocks, from the receiving side to the transmitting side to enable indication whether any soft information associated with at least one sub-block of the data block has been stored in memory at the receiving side. This information helps the transmitter to select which of the data blocks that may be suitable to retransmit next. For example, by first retransmitting data blocks for which one or more sub-blocks are already stored in the receiver memory, the probability of successful decoding of these data blocks increases, and thus the corresponding sub-blocks can be removed from memory, allowing room for sub-blocks of new data blocks. This significantly improves the utilization of the memory on the receiving side, increases throughput and reduces delay.