Comparison Study Between PD-NOMA and SCMA

In this paper, the performance and system complexity of the candidate multiple access (MA) techniques for the next generation of cellular systems, namely, power domain nonorthogonal multiple access (PD-NOMA) and sparse code multiple access (SCMA), are investigated. To this end, for each MA technique, a resource allocation problem considering heterogeneous cellular networks is formulated. We apply successive convex approximation method to each problem and obtain their solutions. Simulation results show that SCMA-based system achieves better performance than PD-NOMA-based one at the cost of more complexity.