Edge Selection-Based Low Complexity Detection Scheme for SCMA System

Sparse code multiple access (SCMA), as a promising non-orthogonal multiple access approach, can support massive access devices communications for cellular the Internet of Things (IoT). This paper focuses on the research of low complexity detection scheme for SCMA system. Although the original message passing algorithm (MPA) detector achieves nearly optimal bit error ratio (BER) performance for SCMA system, the high computation complexity makes it hard to implement in practice. To handle this problem, we propose a low complexity detection scheme based on the edge selection. The message passing from function nodes (FNs) to variable nodes (VNs) on factor graph model is updated only with partial selected edges, furthermore the information loss brought by the edge selection is compensated via the mean feedback. Numerical results demonstrate that the proposed scheme can achieve an affordable trade-off between BER performance and complexity for SCMA system.