Evidence Theory Based Self-Interference Suppression for Two-Way Full-Duplex MIMO Relays

In this paper, a novel self-interference (SI) suppression scheme based on Dempster-Shafer (D-S) evidence theory is proposed to cancel self-interference in two-way full-duplex (FD) MIMO relay. D-S evidence theory can appropriately characterize uncertainty and make full use of multiple evidence source information by Dempster´s combination rule to obtain reliable decisions. Instead of traditional spatial-domain suppression schemes, the proposed DS-Sum and Difference(SAD)-PNC scheme adopts D-S evidence theory to detect the sum and difference signal for two source nodes considering the SI cancellation in obtaining basic probability assignment (BPA) function in the multiple access (MA) phase. For comparison, Log-Likelihood-Ratio (LLR) combining technique is extended for FD mode with SI suppression considered in soft information computation for network-coded symbol. In the broadcast (BC) phase, antenna selection scheme is adopted to achieve full transmit diversity gain. Simulation results reveal that the proposed DS-SAD-PNC scheme obtains better end-to-end average bit error rate (BER) performance compared with extended MIMO-LLR-PNC and traditional spatial-domain suppression schemes like ZF and MMSE with a little complexity increased.