Limited Feedback Unitary Precoding for MIMO Full Stream Transmission

Limited feedback precoding (LFP) significantly improves multiple-input-multiple-output (MIMO) spatial multiplexing link reliability with a small amount of feedback from the receiver back to the transmitter. One of the key problems with LFP is how to select an optimal precoder from a predetermined unitary codebook. We find that the conventional precoder selection criteria are not applicable to the full stream transmission mode with linear [zero forcing (ZF) and minimum mean square error (MMSE)] receivers. To solve this issue, a novel singular value decomposition (SVD)-based precoder selection criterion optimizing the bit error rate (BER) performance is proposed in this paper. The proposed criterion features a unified structure for both linear receivers and it can be calculated based on fast matrix computation algorithms. Its effectiveness in the full stream transmission mode is verified by simulation results.