Arbitrary decode-forward relaying with re-encoded bits selection strategy for polar codes

In this paper, we propose an arbitrary decode-forward single-relay scheme for finite block-length polar codes, which can be applied to the general symmetric discrete memoryless relay channel with orthogonal receiver components. The relay node decodes the received message. The relay node selectively re-encodes the message and transmits it to the destination node. Furthermore, in order to minimize the upper-bound of the block error probability, we propose a selection strategy to decide the proper re-encoded bit set by the relay. Simulation results are presented to illustrate the improvement in decoding performance of the proposed scheme compared to conventional relay schemes in both additive white Gaussian noise (AWGN) channel and Rayleigh fading channel (RFC).