Multi-Group Multiuser Two-Way Relay with Superposition Coding

In this paper, we investigate the application of superposition coding to multi-group multiuser two-way relay channel. A novel scheme combining network coding and superposition coding is proposed. In the two-phase communication scenario considered, single-antenna users of each group wish to exchange information with their corresponding partners with the assistance of the relay node (RN) which is equipped with multiple antennas. Decode-and-forward (DF) strategy is employed by RN. Network coding is used to handle intra-group interference while superposition coding is deployed to cope with inter-group interference. We make explicit analysis of ergodic sum rate and outage probability which are chosen as the metrics to evaluate the performance of the proposed scheme. Space-time coding (STC) adopted by the multi-antenna RN enables the users to achieve spatial diversity gain. It shows that the proposed scheme outperforms other existing comparable approaches in terms of sum rate and outage probability. Simulation results are provided to verify our analysis and demonstrate the performance of the proposed scheme.