Patent ID: 8855229

Claim:
A method for transmitting information in a closed-loop multi-antenna system, comprising: receiving, by a transmitting device, information comprising codeword index information transmitted from a receiving device; selecting, by the transmitting device, a corresponding codeword from a codebook in a two-stage structure according to the codeword index information; generating, by the transmitting device, a pre-coding matrix from the selected codeword; pre-coding, by the transmitting device, data to be transmitted according to the pre-coding matrix; and transmitting, by the transmitting device, the pre-coded data to the receiving device; wherein a codeword c n r in the codebook in the two-stage structure satisfies the following relationship: c n r = ⁢ [ Φ k r ⁡ ( : , 1 ) ⊗ w m r ⁡ ( : , 1 ) Φ k r ⁡ ( : , 2 ) ⊗ w m r ⁡ ( : , 2 ) … Φ k r ⁡ ( : , r ) ⊗ w m r ⁡ ( : , r ) ] = ⁢ [ Φ k r ⁡ ( 1 , 1 ) ⁢ w m r ⁡ ( : , 1 ) Φ k r ⁡ ( 1 , 2 ) ⁢ w m r ⁡ ( : , 2 ) … Φ k r ⁡ ( 1 , r ) ⁢ w m r ⁡ ( : , r ) Φ k r ⁡ ( 2 , 1 ) ⁢ w m r ⁡ ( : , 1 ) Φ k r ⁡ ( 2 , 2 ) ⁢ w m r ⁡ ( : , 2 ) … Φ k r ⁡ ( 2 , r ) ⁢ w m r ⁡ ( : , r ) ] , wherein Φ k r is a 2×r-dimension matrix, k=0, 1, . . . , K−1, w m r is a N T /2×r-dimension matrix, m=0, 1, . . . , M r −1, r is the number of Ranks, N T is the number of transmitting antennas, X(:,l) represents the l th column of a matrix X, X(l 1 ,l 2 ) represents an element in the l 1 th row and in the l 2 th column of the matrix X, and represents a direct product of matrices; and a set consists of a number K r of Φ k r is a transformation codebook of the codebook in the two-stage structure, and a set consists of a number M r of w m r is a basic codebook of the codebook in the two-stage structure.