Various embodiments disclosed herein provide for a base station device that can determine which layers should be mapped to codewords in a multi-layer, multi-antenna transmission. The base station device can transmit reference signals to a user equipment device, with each reference signal associated with a respective codeword to layer mapping combination, and the user equipment can send channel state information associated with each reference signal back to the base station device, and the base station device can rank each combination in terms of spectral efficiency or capacity and/or throughput. The base station device can inform the user equipment of the ranked combinations by sending a bit map with the ranked combinations to the user equipment device.