Rateless Superposition Spinal Coding Scheme for Half-Duplex Relay Channel

In this paper, we propose a rateless superposition spinal coding scheme for the half-duplex relay channel, which is an optimal realization of the information theoretic coding scheme for decode-and-forward (DF) relaying. The proposed coding scheme has a simple coding structure and can be implemented flexibly. More importantly, the encoders and decoders can maintain unchanged for varying channel conditions. We also contribute to the optimization of the proposed coding scheme, which can provide an excellent rate performance. Since only two parameters are considered in the optimization, the optimization can be realized with low complexity. Furthermore, we prove that the proposed coding scheme can achieve the theoretic limit of half-duplex DF relaying. Simulation results show that the average transmission rates of the proposed coding scheme are very close to the theoretic limits for both Gaussian relay channel and fading relay channel.