关键词: 多用户MIMO, 正交频分复用, 预编码, 有限反馈, 双码本

Abstract: Considering the problem of performance loss due to limited feedback in multiuser MIMO-OFDM downlink systems, an novel limited feedback precoding for multiuser MIMO systems based on double codebook is proposed. Only a part channels of subcarrier should be estimated, the maximum SINR criteria is used for selecting optimal codeword from the Grassmannian codebook and perturbation codeword at the receiving, exploiting the correlation between sub-carrier channels of OFDM（Orthogonal Frequency Dvision Multiplexing）, to feedback the Grassmannian precoding codeword index and perturbation codeword index to the transmitter and reconstructing the other precoding matrix, then the perturbation codeword is used at the transmitter to get optimal capacity, and compensating for the capacity performance loss due to the limited feedback. Simulation results show that the proposed method to ensure BER performance and the cost of the feedback link, the system throughput are improved effectively.

Key words: multiuser MIMO, Orthogonal Frequency Dvision Multiplexing（OFDM）, precoding, limited feedback, double codebook