Joint Source-Relay Precoding with MMSE-based Interference Suppression in two-way MIMO Amplify and Forward Relays

In this paper, we consider a two-way multiple input multiple output (MIMO) Amplify-and-Forward (AF) relay system, where interference is observed at the relay node during the multiple access (MAC) phase. For such a scenario, two new joint source-relay precoding algorithms with interference suppression are proposed and their performance analyzed through simulation results. These linear minimum mean-squared error (MMSE) based receiver algorithms provide acceptable error rate performance even in the presence of strong interference. Additionally, the effect of number of relay antennas and the number of interference streams on the overall diversity of the system is also investigated. We show that it is possible to handle interference at the relay node at the cost of losing some of the diversity gain offered by the extra antennas available at the relay.