基于SSCANL译码器的联合迭代检测译码算法

为了提升基于极化码的稀疏码多址接入（sparse code multiple access，SCMA）系统接收机性能，提出了基于简化软消除列表（simplify soft cancellation list，SSCANL）译码器的循环冗余校验（cyclic redundancy check，CRC）辅助联合迭代检测译码接收机方案。该方案中极化码译码器使用SSCANL译码算法，采用译码节点删除技术对软消除列表（soft cancellation list，SCANL）算法所需要的L次软消除译码（soft cancellation， SCAN）进行简化，通过近似删除冻结位节点，简化节点间软信息更新计算过程，从而降低译码算法的计算复杂度。仿真结果表明，SSCANL算法可获得与SCANL算法一致的性能，其计算复杂度与SCANL算法相比有所降低，码率越低，算法复杂度降低效果越好；且基于SSCANL译码器的CRC 辅助联合迭代检测译码接收机方案相较基于SCAN译码器的联合迭代检测译码（joint iterative detection and decoding based on SCAN decoder， JIDD-SCAN）方案、基于SCAN译码器的CRC辅助联合迭代检测译码（CRC aided joint iterative detection and decoding based on SCAN decoder，C-JIDD-SCAN）方案，在误码率为10^-4时，性能分别提升了约0.65 dB、0.59 dB。

SSCANL decoder based joint iterative detection and decoding algorithm

In order to improve the receiver performance of the sparse code multiple access (SCMA) system based on polar codes, the cyclic redundancy check (CRC) aided joint iterative detection and decoding receiver scheme based on simplify soft cancellation list (SSCANL) decoder (C-JIDD-SSCANL) was proposed.A polar code decoder in the C-JIDD-SSCANL receiver used the SSCANL algorithm.In this algorithm, decoding node deletion technology was used to simplify L times of soft cancellation (SCAN) decoding required by soft cancellation list (SCANL) algorithm by deleting frozen bit nodes, then the computational process of soft information update between nodes was simplified, and the computational complexity of decoding algorithm was reduced.The simulation results show that the SSCANL algorithm can obtain the same performance as the SCANL algorithm, and its computational complexity is reduced compared with the SCANL algorithm.Compared with the joint iterative detection and decoding scheme based on SCAN decoder (JIDD-SCAN) and the CRC aided joint iterative detection and decoding scheme based on SCAN decoder (C-JIDD-SCAN), the performance of C-JIDD-SSCANL receiver scheme based on SSCANL decoder is improved by about 0.65 dB and 0.59 dB respectively when the bit error rate is 10^-4.