Patent ID: 8644422

Claim:
A method for searching for a pairing precoding matrix indicator (PMI), comprising: estimating a multiple input/multiple output (MIMO) wireless propagation channel from an access point transmitter to a receiver at a user equipment (UE); quantizing the estimated channel with a codebook consisting of a plurality of codewords, the quantization result being an actual single user MIMO (SU-MIMO) PMI of a plurality of potential SU-MIMO PMIs currently applicable to the UE; estimating a channel quality corresponding to the actual SU-MIMO PMI, resulting in at least one channel quality indicator (CQI) for the UE; constructing a plurality of subsets from the codebook of codewords, wherein each subset comprises potential multi-user MIMO (MU-MIMO) PMIs that represent channels that have reduced interference with a channel represented by one of the plurality of potential SU-MIMO PMIs; associating each of the plurality of potential SU-MIMO PMIs with a subset of the plurality of subsets that comprises the potential MU-MIMO PMIs that represent channels that have reduced interference with the channel represented by the each of the plurality of potential SU-MIMO PMIs; searching for an appropriate potential MU-MIMO PMI and an associated CQI for the UE only in the subset associated with the each of the plurality of potential SU-MIMO PMIs that is the same as the actual SU-MIMO PMI for the UE; and pairing the appropriate potential MU-MIMO PMI with the actual SU-MIMO PMI for the UE.