Patent ID: 9698881
Date: 2017-07-04
CPC Classifications: H04B

Claim:
1. A method by a network node in a communications system, the method comprising: determining a codebook subset restriction indicating a reduced set of precoding matrices out of an original set of precoding matrices in an original codebook, wherein a full set of Precoding Matrix Indicator, PMI, bits is used to identify the original set of precoding matrices in the original codebook; determining a reduced set of PMI bits for use in a feedback channel based on a number of entries in the reduced set of precoding matrices, wherein the reduced set of PMI bits has fewer bits than the full set of PMI bits; determining a mapping of the entries in the reduced set of precoding matrices to entries in the original set of precoding matrices; and decoding signals from the feedback channel using the reduced set of PMI bits.