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

— We 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 bitwise XOR and symbol-level superposition coding. We first derive its achievable rate regions when integrated with two known time control protocols over Gaussian channels. We then demonstrate its average maximum sum-rate and service delay performance over fading channels. Compared with the existing bitwise XOR and symbol-level superposition coding, the proposed superimposed XOR scheme achieves larger rate region in asymmetric channels. As a result, it performs much better in terms of averaged maximum sum-rate and service delay over fading channels. Numerical results also show that the proposed practical PLNC closely approaches the capacity bound given by the informationtheoretic random binning.

• Type: Conference
• Year: 2009
• Where: GLOBECOM
• Authors: Jianquan Liu, Meixia Tao, Youyun Xu, Xiaodong Wang
• Keywords: Bitwise Xor, GLOBECOM 2009, Symbol-level Superposition Coding, Telecommunications , Two-way Relay Channels