DOUBLY WEIGHTED DFT-BASED FEEDBACK CODEBOOK DESIGN FOR ORTHOGONAL SPACE-TIME BLOCK CODES

A doubly weighted DFT-based feedback codebook design for systems using linear precoding scheme and orthogonal space-time block codes (OSTBCs) is proposed. The proposed codebook design employs a two-stage phase-amplitude weighting of the DFT codewords, which can be better to match the channel state information (CSI) than that using phase-weighting only [1]. With the same amount of feedback bits, say 10 bits (1024 possible codewords), our codebook design can not only save a lot of codeword searching operations (80 vs 1024), but also achieve a precoding performance more close to the optimal scheme with full CSI feedback. The simulation results demonstrate that the proposed scheme is superior to the existing codebook design schemes in terms of both BER performance and computational complexity.