4TX codebook enhancement in LTE

摘要

Channel state information (CSI) feedback in a wireless communication system is disclosed. A precoding matrix is generated for multi-antenna transmission based on precoding matrix indicator (PMI) feedback, wherein the PMI indicates a choice of precoding matrix derived from a matrix multiplication of two matrices from a first codebook and a second codebook. In one embodiment, the first codebook comprises at least a first precoding matrix constructed with a first group of adjacent Discrete-Fourier-Transform (DFT) vectors. In another embodiment, the first codebook comprises at least a second precoding matrix constructed with a second group of uniformly distributed non-adjacent DFT vectors. In yet another embodiment, the first codebook comprises at least a first precoding matrix and a second precoding matrix, where said first precoding matrix is constructed with a first group of adjacent DFT vectors, and said second precoding matrix is constructed with a second group of uniformly distributed non-adjacent DFT vectors.

主权项

1. A method of channel state information (CSI) feedback in a wireless communication system, comprising:
receiving one or more precoding matrix indicator (PMI) signals from a remote transceiver; and generating a precoding matrix W derived from a matrix multiplication of two matrices W1 and W2, where said precoding matrix W is applicable to precoding one or more layers of data streams, matrix W1 selected from a first codebook C1 based on a first group of bits in the PMI signals, and matrix W2 selected from a second codebook C2 based on a second group of bits in the PMI signals, wherein the first codebook C1 comprises the following W1 matrices:
C1={W1(0),W1(1),W1(2), . . . ,W1(15)}and matrix W1(k), for k=0, 1, . . . , 15, can be written in the formW1(k)=[X(k)00X(k)],where 0 is a matrix with all entries equal to zero and X(k) is a matrix having two or more columns where at least one column is equal to bk mod N and at least one column is equal to b(k+N/2)mod N wherebk=[1ⅇj2π⁢⁢k/N]and N=32.