New approach to joint MIMO precoding for 2-way AF relay systems

In this paper, we propose methods for joint design of source relay precoders that optimize the performance of two-way amplify and forward (AF) multiple input multiple output (MIMO) relay systems. In particular, we propose three iterative methods to optimize the system performance. The design criteria we consider in this paper are, the conventional Arithmetic sum of average Mean Square Error (AMSE) criteria, and the lesser know Arithmetic sum of average Bit Error Rate (ABER) criteria. The proposed methods are applicable to any number antennas at all three nodes which is advantage compared to the existing joint source relay optimization technique that optimizes the sum rate. Using the extensive simulations we observe that the proposed methods performs better than the existing techniques. By using a judicious combination of both the ABER and AMSE criteria, joint MIMO precoders for two-way relay system are constructed, which clearly outperform existing joint design.