Reducing the Feedback Overhead for Adaptive MIMO Multicarrier Transmission

Appropriate scheduling and link adaptation are key techniques to realize the significant throughput gain for systems which exploit multiple-input multiple-output (MIMO) in conjunction with orthogonal frequency division multiplexing (OFDM). In many cases, however, achieving this gain requires feedback of the channel quality indication (CQI) information to the transmitter, which may lead to high overhead. In this paper, a method of reducing the total amount of feedback for adaptive multistream multicarrier transmission is proposed. This method can make flexible use of the fading channel variance by permuting the original CQI sequences according to certain permutation pattern, which forms the input of the CQI compression module. Through analysis and simulations, we find that the optimal permutation that minimize the amount of the feedback is determined by the fading parameters such as the coherent bandwidth and the antenna number, as well as by the multistream transmission scheme exploited.