Adaptive Transmission Combining Physical-Layer Network Coding and Successive Interference Cancellation for Two-Way Relay System

When two wireless terminals exchange information through an intermediate relay, physical-layer network coding (PNC) improves the spectrum efficiency by allowing concurrent message transmission. In two-way relay systems, the performance gain of PNC under practical limits has been investigated. The results show that generally the performance would be significantly degraded by channel impairments like asymmetric channel gain at the multiple-access phase. As an alternative interference exploitation scheme, successive interference cancellation (SIC) works well when multiple sources’ signals have different power levels at the destination to successfully decoding. In this paper, an adaptive transmission scheme combing PNC and SIC is proposed for the two-way relay systems. Separate sum-rate simulation results for PNC and SIC show the opposite tendency with the channel impairment in two-way relaying, which means combining them would get a smooth sum-rate gain and let the system be more robust to dynamic scenarios.