Non-Regenerative Multi-Way Relaying: Ordered MMSE-SIC Receivers Exploiting Temporal Diversity

We consider the multi-way relaying (MWR) network, where each user communicate with the other users through a relay. The single-antenna users transmit to the multi-antenna relay simultaneously. Then the relay randomly precodes the received or estimated signal, and broadcasts it back to all the users. Focusing on a specific user, we set up the equivalent space-time channel from the other users to it. Afterwards, for both amplify-and-forward and estimate-and-forward MWR, we design the ordered minimum mean square error (MMSE) receivers with successive interference cancellation (SIC) at users. In particular, three types of metrics determining the order of SIC are derived by approximating the interference-plus-noise term as Gaussian. Simulation results on error performance evidence that our proposed receivers are able to harvest the inherent temporal diversity gains within the MWR networks. Moreover, the proposed receivers perform even well in the overloaded scenarios.