Patent ID: 8064394

Claim:
A method for transmitting an information signal on a radio channel using hybrid automatic retransmission request (HARQ) codewords comprising: generating at least two codewords, one for each HARQ process available for simultaneous transmission; mapping said at least two codewords onto a first plurality of layers to generate said information signal having a first transmission rank, wherein at least one of said at least two codewords is mapped to at least two layers; initially transmitting said information signal on said radio channel; and subsequently retransmitting a block of information bits in one of the at least two codewords that was mapped to at least two layers, with a second transmission rank on said radio channel, wherein the second transmission rank is at least two, and wherein the second transmission rank is reduced compared to the first transmission rank, using one of said HARQ processes, the retransmitting comprising the steps of: generating one retransmission codeword based on said block of information bits in said one of the at least two codewords; mapping said retransmission codeword to a second plurality of layers, and transmitting said retransmission codeword at said second transmission rank, wherein the second plurality of layers are fewer than the first number of layers and the same number of layers that said one of the at least two codewords was mapped to in the initial transmission, and wherein said second plurality of layers corresponds to as many layers as said second transmission rank.