MSINR based precoding design for non-regenerative MIMO relay system

The maximum signal-to-interference plus noise ratio (MSINR) design criterion is proposed in this paper to maximize the geometric product of signal-to-interference plus noise ratio (GEOM-SINR) in non-regenerative MIMO relay system. It is shown that the optimal MSINR based precoding at relay will diagonalize the equivalent source-relay-destination channel into parallel sub-channels, and the MSINR based MIMO relay precoding design will be transformed into the MSINR criterion based power allocation among multiple sub-channels. Simulation results are presented to corroborate the MSINR-based MIMO relay precoding design. It is unveiled that, compared with the existing maximal mutual information (MMI) based MIMO relay precoding design and the minimal mean square error (MMSE) based MIMO relay precoding design, MSINR-based MIMO relay precoding design is able to achieve a better tradeoff between the communication reliability and the realized ergodic capacity. © 2012 IEEE

Constructive Interference Beamforming for Cooperative Dual-Hop MIMO Relay Systems - Invited Paper

In this paper, we consider the downlink transmission for a dual-hop amplify-and-forward (AF) multiple-antenna relay systems, where we propose beamforming techniques for interference exploitation on a symbol level. Based on the constructive interference (CI), we firstly propose a joint source/relay precoding, where the precoding matrices at the source and the output signals at the relay are jointly optimized. To alleviate the high computational costs and circumvent the difficulty of practical implementation of the joint design, we further propose a low-complexity decoupled approach, where a closed-form linear precoding method is first employed at the source, and we then optimize the beamforming matrix at the relay for interference exploitation. It is revealed by numerical results that the proposed approaches that exploit the instantaneous interference can achieve an improved performance over the conventional case with a linear approach