On the Self-Decoding of Polar-Coded HARQ

In this letter, we concern the self-decoding capability of polar-coded hybrid automatic repeat request (Polar-HARQ) schemes. The proposed self-decoding method enables the incremental redundancy (IR) based Polar-HARQ to recover all source bits solely using the retransmission codewords. It provides an extra decoding chance when the joint decoding attempt fails. With this, the final decoding success probability increases such that the number of retransmissions can be reduced and the system latency goes down. We derive one necessary condition for the successful self-decoding, which can also guide the optimization of Polar-HARQ. Three mainstream Polar-HARQ schemes are compared from the perspective of self-decoding. Simulation results validate the analysis.