基于部分码字消息传递的SCMA多用户检测算法

基于消息传递算法(MPA)进行多用户检测的稀疏码多址接入(SCMA)技术是一种面向5G的非正交多址技术(NOMA)。针对MPA复杂度较高的问题，该文首先分析接收信号概率密度函数值在不同信噪比(SNR)下的统计结果，并根据SCMA的非正交特性，综合考虑资源节点和用户节点之间的数据映射关系，提出基于概率密度函数值门限判决的部分码字搜索(PCS)MPA多用户检测算法(PCS-MPA)。仿真结果表明，在门限值合理的条件下，PCS-MPA在几乎不改变系统误比特率(BER)的条件下，降低了MPA的复杂度，尤其在高SNR条件下效果更好。

Message Passing Multiuser Detection Algorithm for SCMA Based on Partial Codewords Searching

Sparse Code Multiple Access (SCMA), based on Message Passing Algorithm (MPA) for multiuser detection, is a Non-Orthogonal Multiple Access (NOMA) scheme proposed to meet the demands of the future 5G communication. For the problem that the MPA has the characteristics of high algorithm complexity, some statistical results for the Probability Density Function (PDF) of received signal at various Signal to Noise Ratio (SNR) are first derived. Then, data mapping relationship between resources node and users node is fully considered based on the non-orthogonal property of SCMA, therefore a Partial Codewords Searching of MPA (PCS-MPA) is proposed with threshold decision scheme of PDF. Simulations results show that the proposed PCS-MPA can reduce the complexity without changing the Bit Error Ratio (BER), especially at the case of high SNR.