基于串行策略的SCMA多用户检测算法

摘要

稀疏码多址接入(SCMA)作为一个前景广阔的5 G无线空口技术，能够满足海量连接的需求。针对现有SCMA 通信系统都是基于并行策略的消息传递算法(MPA)进行多用户检测，存在信息收敛速度不理想的问题，该文提出一种串行策略的多用户检测算法。该算法以资源节点为序，按串行方式依次进行消息更新与传递，保证更新的消息能够立即进入当前迭代过程，改善了消息传递的收敛速度，相比并行策略的多用户检测算法，降低了算法复杂度；同时，充分利用消息间相互关联的特点，融合消息传递步骤，降低了存储器的要求。理论与仿真结果表明，该算法在误比特率(BER)性能与算法复杂度之间可以达到较理想的平衡。%Sparse Code Multiple Access (SCMA) is a promising air-interface technology for 5 G wireless communication networks, which can enable massive connectivity. The existing multiuser detection schemes are based on a parallel message updating for Message Passing Algorithm (MPA), thus it is not efficient in terms of convergence. In this paper, an efficient multiuser detection scheme for uplink SCMA is proposed based on serial updating of function nodes, messages. Compared to the existing detection schemes, the proposed scheme accelerates the convergence due to that the updated messages can join the belief propagation immediately in current iteration, which avoids being used in the next iteration. Furthermore, the proposed scheme can reduce the storage burden, which fuses message passing process on the basis of the relationship between messages. Numerical results show that the proposed scheme can offer a good trade-off between complexity and Bit Error Rate (BER) performance.