Channel reciprocity based frequency domain CQI feedback algorithm in TD-LTE-A systems

In TD-LTE-A systems, feedback information of uplink channel is of importance for eNodeB to perform downlink scheduling, beamforming, and adaptive Modulation and Coding Scheme (MCS). Channel quality indicator (CQI) is the most important parameter in all feedback information, and therefore, how to improve the accuracy of CQI feedback is a key issue for system configuration. In this paper, we propose a frequency domain CQI feedback algorithm, using channel capacity invariability criterion and channel reciprocity. Simulations show that periodic feedback with frequency domain CQI feedback algorithm can reduce system first retransmission ratio by about 4% and improve system throughput by about 7%, compared with normal periodic feedback Mode 1-1. In addition, compared with aperiodic feedback Mode 3-1, the proposed CQI feedback algorithm costs less signaling overhead, while keeping similar performance in terms of system first retransmission ratio.