改进型极化码混合自动请求重传法

极化码与混合自动请求重传结合的传输方案适用于物联网应用的短数据包场景。现有的极化码与蔡司合并结合的传输方案能够提供合并增益，但并未提供编码增益。极化码与增量冗余结合的传输方案能够获得更好的性能，但计算复杂度较高，不适用于短数据包场景。该文提出一种改进型极化码与混合自动请求重传结合的传输方案。与现有的极化码与蔡司合并结合的传输方案相比，当码率为1/2、重传次数为1时，该方案能够获得额外的0.7 dB的编码增益，与码率为1/4的极化码性能相近。该文所提方案的编译码复杂度相比于码率为1/4的极化码，降低了50%的复杂度。仿真结果验证了该方案的有效性。

An Improved HARQ Scheme with Polar Codes

Hybrid Automatic Repeat reQuest (HARQ) scheme with polar codes is suitable for short packets applied to Internet of Things (IoT). Existing HARQ scheme with Chase Combing (HARQ-CC) provides combining gain without coding gain. The HARQ scheme with Incremental Redundancy (HARQ-IR) achieves better performance with significantly high complexity, which is unacceptable for IoT applications. In this paper, an improved HARQ scheme with polar codes is proposed. The proposed coding scheme achieves 0.7 dB gain for code rate R=1/2 and retransmission time T=1 compared with HARQ-CC scheme and the performance of this scheme is approaching the polar codes with rate R=1/4. The encoding and decoding complexity of the proposed scheme is reduced by about 50% compared with the polar codes with rate R=1/4. Simulation results validate the effectiveness of this scheme.