基于Polar码的速率兼容调制方案设计

提出了一种基于Polar码的速率兼容调制（rate compatible modulation，RCM）联合设计方案，用于提高无线通信频谱利用率.相应地设计了基于置信度传播（belief propagation，BP）和软抵消（soft cancellation，SCAN）的接收端高效联合迭代译码算法.根据该算法可通过优化变量节点对数似然比（log-likelihood ratio，LLR）信息迭代方式以及采用限制译码符号上限的改进措施，提高译码过程的稳定性与时效性.与距离优化的级联低密度奇偶校验（low-density parity-check codes，LDPC）码RCM方案对比结果表明，提出的高效联合迭代译码算法在低信噪比（signal noise ratio，SNR）下有更低的译码复杂度，并且具有更优的吞吐量和误码率性能.因此，本文所提方案适合在恶劣信道条件下的无线传输.

The design of rate compatible modulation scheme based on Polar code

A joint design scheme of rate compatible modulation (RCM) based on polar codes is proposed to improve the spectrum utilization rate of wireless communication. Correspondingly, an efficient joint iterative decoding algorithm based on belief propagation (BP) and soft cancellation (SCAN) is designed. According to the algorithm, the stability and timeliness of the decoding process can be improved by optimizing the information iteration method of the variable node log-likelihood ratio (LLR) and adopting the improvement measures of limiting the upper limit of decoding symbols. Finally, compared with the scheme of RCM based on the distance-optimized cascade low-density parity-check codes(LDPC), the proposed efficient joint iterative decoding algorithm has lower decoding complexity under low signal-to-noise ratio conditions, and has better throughput and bit error rate performance. Therefore, the scheme proposed in this paper is suitable for wireless transmission under harsh channel conditions.