Precoding for MIMO Full-Duplex Amplify-and-Forward Relay Communication Systems

This paper considers the linear source and relay precoders and destination combiner design for a multiple-input multiple-output (MIMO) full-duplex (FD) amplify-and-forward (AF) relay communication system. The effect of the residual interference due to imperfect loop interference (LI) cancellation is also considered. By taking the full-duplex relay into account, an iterative algorithm is proposed to minimize the mean squared error (MSE) of the received signal at the destination. The original non-convex problem is converted into three convex subproblems, and these are solved alternately to obtain a suboptimal solution to the design problem. The convergence of the iterative algorithm is investigated. Results are presented which show that the proposed FD relay communication system can approximately double the achievable rate compared to the corresponding half-duplex (HD) system when the residual LI level is not high.