Patent ID: 8913682

Claim:
A mobile station configured to receive transmissions from a two-dimensional array of antennas at a base station, wherein the array comprises a plurality of groups of antennas, the mobile station comprising a main processor, the main processor configured: to receive from the base station a first configuration for a first set of reference signals and a second configuration for a second set of reference signals; to estimate a first channel state with the first set of reference signals and a second channel state with the second set of reference signals; to determine a co-phasing scalar component for each of the groups of antennas based on the first channel state; to generate a matrix X comprising a plurality of column vectors selected from a codebook based on the second channel state, wherein each of the column vectors quantizes channel coefficients for one of the groups of antennas; to generate a matrix P 1 , wherein the matrix P 1 comprises a block diagonal matrix having the matrix X for each block diagonal element; to generate a matrix P 2 comprising a plurality of vector elements, wherein each vector element comprises one of the co-phasing scalar components and a column selector vector configured to select a column of the matrix X; to transmit to the base station a first precoding matrix information corresponding to the matrix P 1 and a second precoding matrix information corresponding to the matrix P 2 ; and to transmit to the base station a channel quality information (CQI), wherein the CQI is derived with a precoding matrix P defined by P=P 1 P 2 .