一种非二进制LDPC与SCMA系统的联合检测译码方案  

A joint detection decoding scheme for non-binary LDPC and SCMA system

作　　者：孙垠 葛文萍[1] 乔威 张世伟 SUN Yin;GE Wenping;QIAO Wei;ZHANG Shiwei(School of Information Science and Engineering,Xinjiang University,Urumqi 830046,China)

机构地区：[1]新疆大学信息科学与工程学院,乌鲁木齐830046

出　　处：《中国科技论文》2024年第2期241-248,共8页China Sciencepaper

基　　金：新疆维吾尔自治区自然科学基金资助项目(2022D01C426)。

摘　　要：针对现有的一些低密度奇偶校验码(low-density parity code,LDPC)与稀疏码多址(sparse code multiple access,SCMA)系统联合检测方案复杂度高、误码率高、传输时延大、收敛速度慢的问题,提出一个非二进制低密度奇偶校验码(non-binary lowdensity parity code,NB-LDPC)与SCMA系统的联合检测译码(joint detection decoding,JDD)方案。在SCMA多用户检测部分改进基于阈值辅助的期望传播算法(expect propagation algorithm,EPA),在LDPC部分采用NB-LDPC并且在两节点更新过程选取部分消息状态值来改进译码算法,同时,利用联合因子图在联合检测译码信息交互时加入一种消息阻尼因子来提高收敛速度,最终完成联合检测译码过程。通过多角度仿真发现,该方案降低了复杂度和误码率,减小了传输时延,提高了收敛速度,并且在不同码本下均验证了所提方案的适用性。In order to solve the problem of high complexity,high bit error rate,large transmission delay and slow convergence rate existing in current joint detection scheme including low-density parity code(LDPC)and sparse code multiple access(SCMA),a joint detection decoding(JDD)scheme,with the combination of non-binary low-density parity code(NB-LDPC)and SCMA sys-tem,was proposed.The threshold-assisted expectation propagation algorithm(EPA)in SCMA was improved,NB-LDPC was adopted in the LDPC part and some message status values were selected in the update process of two nodes to improve the decoding algorithm.Meanwhile,a message damping factor was added to the joint factor diagram when decoding information during joint detec-tion was exchanged.Then joint detection decoding process was completed.Through multi-angle simulation,it is found that the scheme reduces the complexity,the bit error rate and the transmission delay,improves the convergence speed,and verifies the appli-cability of the proposed scheme under different code books.

关 键 词：稀疏码多址 低密度奇偶校验码 联合检测译码 期望传播算法 消息阻尼因子 

分 类 号：TN929.5[电子电信—通信与信息系统]