ADAPTIVE CODEBOOK FOR BEAMFORMING IN LIMITED FEEDBACK MIMO SYSTEMS

摘要

A method for beamforming is described. The method includes generating a pseudo-random unitary matrix. A first codebook is rotated with the pseudo-random unitary matrix. The method includes generating a second codebook based upon the rotated codebook and a correlation matrix. A codeword is selected from the second codebook using a channel matrix. The correlation matrix is updated based upon the selected codeword. The method includes transmitting an index of the selected codeword in the codebook. The method includes receiving the codeword index. A codebook is consulted using the codeword index to locate a codeword. Beamforming is performed based upon the located codeword. An apparatus is also described.