METHOD AND APPARATUS FOR QUANTIZING CHANNEL STATE INFORMATION

摘要

The present invention relates to a method and an apparatus for quantizing channel state information (CSI). An embodiment of the present invention provides a method for providing codeword index information to a base station configured with Nt directional antennas, including: determining a first codeword in a first codebook whose rank is r, where r=1, 2, . . . , Nt, and sending an index of the codeword to the base station; and determining a second codeword in a second codebook whose rank is r, and sending an index of the codeword to the base station. The first codeword is a block diagonal matrix, and a matrix on a diagonal block of the block diagonal matrix is a matrix with Nt/2 rows and Nb columns. The Nb columns are Nb different Discrete Fourier Transform (DFT) vectors arbitrarily selected from N predefined DFT vectors, N is an integer power of 2, 1≦Nb≦N, and the length of each DFT vector is Nt. Each column corresponding to each data stream in the second codeword includes an equal-length column selection vector for individually selecting from the Nb columns in the first codeword the DFT vectors used in two polarization directions and co-phasing information θ=2πm/M between the two polarization directions, where M is an integer power of 2, and 0≦m≦M−1.

主权项

1. A method for providing codeword index information to a base station from a user equipment (UE), the base station being configured with Nt directional antennas, the method comprising:
determining by the UE, according to an estimated broadband channel matrix and based on a first predetermined criterion, a first codeword in a first codebook whose rank is r, wherein the first codeword indicates broadband/long-term channel characteristics of antenna pairs having the same polarization direction, and r=1, 2, . . . , Nt; sending a codeword index of the first codeword to the base station; determining by the UE, for each sub-band according to an estimated sub-band channel matrix and based on a second predetermined criterion, a second codeword in a second codebook whose rank is r, wherein the second codeword indicates sub-band/short-term channel characteristics of each polarization direction and between the polarization directions; and sending a codeword index of the second codeword to the base station, wherein the first codeword is a block diagonal matrix, a matrix on a diagonal block of the block diagonal matrix is a matrix with Nt/2 rows and Nb columns, the Nb columns are Nb different Discrete Fourier Transform (DFT) vectors arbitrarily selected from N predefined DFT vectors, N is an integer power of 2, 1≦Nb≦N, and the length of each DFT vector is Nt; and the second codeword is constructed based on column selection of the first codeword and co-phasing information between the polarization directions, and each column corresponding to each data stream in the second codeword comprises an equal-length column selection vector for individually selecting from the Nb columns in the first codeword the DFT vectors used in two polarization directions and co-phasing informationθ=2πmMbetween the two polarization directions, where M is an integer power of 2, and 0≦m≦M−1.