A Linear Complexity SCMA Detection Algorithm

Abstract

Sparse Code Multiple Access (SCMA) is a promising non-orthogonal multiple access scheme. Although message passing algorithm (MPA) can reduce the detection complexity exploiting the sparsity of SCMA, it is still exponential order. Excessive detection complexity is a major obstacle to SCMA engineering applications. In this paper, based on expectation propagation algorithm (EPA), a linear order complexity SCMA multi-user detection algorithm Max-Log-EPA is proposed. The average block error rate (BLER) simulation results prove that the proposed algorithm has a slight performance loss at low signal-to-noise ratio (SNR), while there is almost no performance loss at high SNR. This indicates that the proposed algorithm can significantly reduce the detection complexity with only a slight performance loss, which greatly promotes the engineering application of SCMA scheme.