Date Added: Nov 2012
In traditional Multiple-Input - Multiple-Output (MIMO) channel and MIMO one-way relay system, nonlinear pre-coding design has shown significant performance gain over linear design. In this paper, the authors aim to study nonlinear pre-coding design for MIMO Amplify-and-Forward (AF) two-way relay systems, where nonlinear Minimal Mean Square Error (MMSE) Decision Feedback Equalizers (DFEs) are used in two destinations, and linear transmit pre-coding is applied at the source and relay nodes. They first investigate nonlinear pre-coding design, where the pre-coding is only conducted at two sources for a fixed-relay pre-coder. After some transformations, they prove that this design problem is convex, and an efficient algorithm is provided to find the optimal solution.