A method for transmitting an information signal on a radio channel using hybrid automatic retransmission request HARQ codewords, the method comprising: generating at least two codewords, one for each HARQ process available for simultaneous transmission; mapping using a codeword-to-layer mapping said at least two codewords onto a first number of layers to generate said information signal having a first transmission rank equal to the first number of layers, wherein at least one of said at least two codewords is mapped to at least two layers and comprises a block of information bits; initially transmitting said information signal on said radio channel; receiving a request to resend the information contained in at least one of the plurality of codewords; retransmitting the block of information bits comprised in said one of the 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 the block of information bits; mapping using a codeword-to-layer mapping said retransmission codeword to a second number of layers; and transmitting said retransmission codeword at said second transmission rank equal to the second number of layers, wherein the second number of layers is the same number of layers that said one of the codewords was mapped to in the initial transmission, and wherein the layers are symbol streams which are input in parallel to a precoder, wherein the codeword-to-layer mapping to be used is signaled by setting to zero the transport format size field corresponding to the codeword that should remain unused. generating at least two codewords, one for each HARQ process available for simultaneous transmission; mapping using a codeword-to-layer mapping said at least two codewords onto a first number of layers to generate said information signal having a first transmission rank equal to the first number of layers, wherein at least one of said at least two codewords is mapped to at least two layers and comprises a block of information bits; initially transmitting said information signal on said radio channel; receiving a request to resend the information contained in at least one of the plurality of codewords; retransmitting the block of information bits comprised in said one of the 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 the block of information bits; mapping using a codeword-to-layer mapping said retransmission codeword to a second number of layers; and transmitting said retransmission codeword at said second transmission rank equal to the second number of layers, wherein the second number of layers is the same number of layers that said one of the codewords was mapped to in the initial transmission, and wherein the layers are symbol streams which are input in parallel to a precoder, wherein the codeword-to-layer mapping to be used is signaled by setting to zero the transport format size field corresponding to the codeword that should remain unused. generating one retransmission codeword based on the block of information bits; mapping using a codeword-to-layer mapping said retransmission codeword to a second number of layers; and transmitting said retransmission codeword at said second transmission rank equal to the second number of layers, wherein the second number of layers is the same number of layers that said one of the codewords was mapped to in the initial transmission, and wherein the layers are symbol streams which are input in parallel to a precoder, wherein the codeword-to-layer mapping to be used is signaled by setting to zero the transport format size field corresponding to the codeword that should remain unused.