The present invention relates to methods and arrangements in a wireless communication system that enable the use of multi-codeword transmission and ACK/NACK compression with low performance loss. It also enables the use of advanced receivers of reasonable complexity. This is achieved by a solution based on the even distribution of the symbols of separately coded blocks of information bits over the available physical resources before transmission. Each physical resource will thus carry a mixture of symbols from all blocks of information bits, which results in a more similar channel quality for the blocks of information bits. A compressed ACK/NACK message corresponding to the blocks of information bits will thus be more accurate and the performance loss due to the ACK/NACK compression can be reduced.