Design Uplink SCMA Codebook by Minimizing the Upper Bound of Error Probability

Sparse Code Multiple Access (SCMA) is a class of competitive non-orthogonal multiple access (NOMA) that is proposed to support massive Machine Type of Communication (m-MTC). In this paper, we propose a new scheme to construct the SCMA codebooks, where we jointly optimize the rotation angles and mother codebook parameters. The basic idea is to make the upper bound of the error probability as smaller as possible. To realize it, we search for suitable angles and parameters through the bare bones particle swarm optimization (BBPSO) algorithm. The simulation results demonstrate that compared with the original SCMA, Star-QAM SCMA and LDS the new proposed SCMA codebooks provides better performance in both additive white Gaussian noise (AWGN) and Rayleigh channels, moreover, it also gives better performance in high overloading.