Research and Improvement on Detection Algorithm of SCMA System

In this paper, a grouping low-complexity MPA detection algorithm (DPG-MPA) based on dynamic pruning is proposed to solve the problem of high computational complexity at the receiver of SCMA system. In this algorithm, users are grouped into groups, and the user nodes in the group adopt the serial message transmission mode, and the priority of updating user information is judged according to the node convergence degree of user information. After a predetermined number of iterations, residual values of user nodes are calculated, nodes whose residual values are lower than the threshold value are marked as trusted nodes, and information values on trusted nodes are stopped in subsequent iterations. Simulation results show that the proposed algorithm can accelerate convergence and reduce redundant operations without losing the system's excellent bit error performance.