An Efficient Low Complexity Gaussian Approximation-Based Scheme for SCMA Detection

Message passing algorithm (MPA) scheme is employed to detect multiuser signals for a sparse code multiple access (SCMA) system. However, the huge complexity of the original MPA scheme makes it hard to be implemented in practice. In this paper, we propose an efficient low complexity detection scheme based on the Gaussian approximation. The original discrete messages on the factor graph are approximated as continuous Gaussian messages, which can avoid the complex marginalization operation of the original MPA scheme, such that the total complexity is reduced to scaling linearly with the codebook size. Besides simulation results demonstrate that our proposed scheme achieves almost the same bit error ratio (BER) performance with the original MPA scheme.