Polar-Coded Physical Layer Network Coding Over Two-Way Relay Channels

Abstract

Both polar codes and physical network coding (PNC) are promising techniques to achieve low-latency and high-rate transmission in 5G communications. In this letter, we investigate a joint polar-coded PNC system over a wireless two-way relay channel (TWRC). By exploiting the nature of PNC, we then propose two successive cancellation list (SCL) decoding schemes for the polar-coded PNC system, XOR-based conventional SCL (XOR-SCL) and joint decoding of PNC and SCL decoding (JPSCL), where message update rules are derived for odd and even channels. Simulation results demonstrate that JPSCL outperforms XOR-SCL over both AWGN and Rayleigh fading channels. In particular, JPSCL achieves a small bit error rate gap, i.e., within 1 dB at rate of 2/5, from SCL in the polar-coded point-to-point system at BER of $10^{-5}$ .