A Low Complexity SCMA Detector Based on Avoiding Redundant Iterations

Sparse code multiple access (SCMA), a competitive air-interface technology with the message passing algorithm (MPA) employed at the receiver, has a broad application prospect. However, the computational complexity of MPA is still an extreme challenge for SCMA decoding. In this paper, a low complexity multiuser detection algorithm based on avoiding redundant iterations, namely Avoiding Redundant Iterations-MPA (ARI-MPA), is proposed for the uplink SCMA system. ARI-MPA can achieve low complexity by avoiding redundant iterations, in which the number of iterations required is determined by the convergence rate of codeword probability. Numerical results demonstrate that the proposed scheme can achieve an affordable trade-off between bit error ratio (BER) performance and decoding complexity for the SCMA system.