Limited Feedback-based Maximum SINR Linear Antenna Combiner for MIMO Broadcast Channels

MultiUser Interference (MUI) caused by channel quantization error degrades the performance of the limited feedback-based multiuser Multiple-Input Multiple-Output (MIMO) systems. Antenna combining techniques can effectively improve the system performance with the additional dimension of freedom. In this paper, a linear antenna combiner is proposed for the feedback overhead allocation strategy which is proved to be the optimal scheme. First, the closed-form lower bound of each users expected post-combining Signal-to-Interference- plus-Noise Ratio (SINR) is derived. Then, using this bound expression, the proposed combiner is obtained which aims to maximize the expected post-combining SINR. Monte Carlo simulations show that the proposed combiner achieves better performance compared with the existing antenna combining algorithms.