Half-duplex relay systems based on polar codes

A cooperative communication scheme based on polar codes is proposed for time-division half-duplex relay systems, where the relay node is either a transmitter or a receiver in different time slots of each transmitting period. To enhance efficiency and reduce latency, the proposed codes utilise the decode-and-forward strategy and appropriate construction of polarisation. The authors prove that carefully constructed polar codes can achieve the theoretical capacity in the half-duplex relay channel, and time-division and information-division parameters are also optimised to improve the performance of the relay system. It is demonstrated that the random selection strategy is more effective than the appointed one. Simulation results show that the proposed scheme is useful not only for time-division half-duplex relay systems but also for other relay cases.