Sparsity-based channel state information acquisition and feedback scheme for MIMO-OFDMA systems

In MIMO-OFDMA (multiple-in multiple-out orthogonal frequency multiple access) based systems, the downlink channel state information (CSI) acquired at the basestation is an important factor to impact the system capacity, since both scheduling and precoding cannot work efficiently without accurate and enough CSI. On the other hand, the CSI feedback overhead should be as small as possible to improve the system efficiency. Obviously, there is a tradeoff between the accuracy and the feedback overhead. In this paper, a CSI acquisition and feedback scheme based on the delay-domain sparsity of channel impulse response is proposed. Analysis and simulation results show that the proposed scheme will guarantee the throughput performance with greatly reduced feedback overhead by comparing with the CQI(channel quality indicator) feedback scheme used in 3GPP LTE(the third generation partner project long term evolution).