上行SCMA系统的串行球形解码MPA算法

Serial Spherical Decoding MPA Algorithm for Uplink SCMA System

稀疏码多址接入(Sparse Code Multiple Access,SCMA)作为5G新型非正交多址技术极大地提升了频谱效率,接收端使用消息传递算法(Message Passing Algorithm,MPA)进行多用户检测,但是MPA的复杂度限制了它在实际系统中的应用。为了降低MPA的复杂度,提升其实际应用性,提出一种串行球形解码消息传递算法(SSD-MPA)。考虑高斯噪声的分布特性,该算法只更新范围内的节点的消息,从而降低了复杂度。同时,该算法利用串行策略加快了收敛速度。仿真结果表明,所提算法在保持MPA性能的同时,减少了收敛所需的迭代次数,并降低了复杂度。

Sparse Code Multiple Access(SCMA),as a new non-orthogonal multiple access technology for 5G,has greatly improved spectrum efficiency.The receiver uses Message Passing Algorithm(MPA)for multi-user detection.However,the complexity of MPA limits its application in practical systems.In order to reduce the complexity of MPA and improve its practical application,a serial spherical decoding message passing algorithm(SSD-MPA)is proposed.Considering the distribution characteristics of Gaussian noise,only the messages of the nodes in the range are updated,and the serial strategy is used to accelerate the convergence speed.Simulation results show that the proposed algorithm reduces the number of iterations required for convergence and reduces complexity while maintaining MPA performance.