Superimposed XOR: A New Physical Layer Network Coding Scheme for Two-Way Relay Channels

The authors present a new Physical Layer Network Coding (PLNC) scheme, called superimposed XOR, for two-way relay channels. The new scheme specifically takes into account the channel as well as information asymmetry in the broadcast phase of two-way relaying. It is based upon both bit-wise XOR and symbol-level superposition coding. They first derive its achievable rate regions when integrated with two known time control protocols over Gaussian channels. They then demonstrate its average maximum sum-rate and service delay performance over fading channels.