短波通信中的低码率CRC-Polar编译码设计与仿真

Design and Simulation of Low Bit Rate CRC-Polar Encoding and Decoding for HF Communication

针对短波通信中业务传输可靠性高的要求,设计了一种低码率循环冗余校验码(Cyclic Redundancy Check,CRC)级联极化(CRC-Polar)编译码算法。首先给出了基于CRC-Polar编译码的短波通信系统模型及参数,讨论了分段CRC校验、低码率构造与编码算法;其次对打孔、缩短及重复等码率适配方案进行对比分析,并针对性地设计了分段CA-SCL译码算法;最后从不同分段、不同码率适配等角度进行了性能仿真。结果表明,重复码率适配的分段CRC8-Polar码性能最好,优于似然比打孔方案约1dB。此外,在加性高斯白噪声(Additive White Gaussian Noise,AWGN)信道条件下,当数据传输速率为300bit/s、误比特率为10^(-4)时,所需信噪比为-6.4dB,优于美军标188-110C约3.4dB,实现了低信噪比下的可靠传输。

In response to the high reliability of service transmission in HF communication,a low bit rate CRC-Polar (Cyclic Redundancy Check-Polar) encoding and decoding algorithm is designed.First,the model and parameters of HF communication system based on CRC-Polar encoding and decoding are presented,and the segmented CRC check,low bit rate construction and coding algorithm are discussed.Then,the code rate adaptation schemes such as punching,shortening and repeating are compared and analyzed,and the segmented CA-SCL decoding algorithm is designed.Finally,the performance simulation is carried out in terms of different segmented and different bit rate adaptation.The results indicate that the segmented CRC8-Polar code with repeated rate adaptation has the best performance,outperforming the likelihood ratio drilling scheme by about 1 dB.In addition,under the condition of AWGN (Additive White Gaussian Noise) channel,when the data transmission rate is 300 bps and the bit error rate is 10^(-4),the required SNR is-6.4 dB,which is better than the U.S.military standard 188-110C by about 3.4 dB,and it achieves the reliable transmission under low SNR.