Joint user grouping and power control using whale optimization algorithm for NOMA uplink system

Abstract

Non-orthogonal multiple access (NOMA) scheme is proved to be a potential candidate to enhance spectral potency and massive connectivity for 5G wireless networks. To achieve effective system performance, user grouping, power control, and decoding order are considered to be fundamental factors. In this regard, a joint combinatorial problem consisting of user grouping and power control is considered, to obtain high spectral-efficiency for NOMA uplink system with lower computational complexity. To solve joint problem of power control and user grouping, for Uplink NOMA, up to authors knowledge, we have used for the first time a newly developed meta-heuristic nature-inspired optimization algorithm i.e. Whale Optimization Algorithm (WOA). Further, for comparison a recently initiated Grey Wolf Optimizer (GWO) and the well-known Particle Swarm Optimization (PSO) algorithms are also applied for the same joint issue.To attain optimal and sub-optimal solutions, a NOMA-based model is used to evaluate the potential of the proposed algorithm. Numerical results validate that proposed WOA outperforms GWO, PSO and existing literature reported for NOMA uplink systems in-terms of spectral performance. In addition, WOA attains improved results in terms of joint user grouping and power control with lower system-complexity as compare to GWO and PSO algorithms. The proposed work is novel enhancement for 5G uplink applications of NOMA systems.