Multiobjective Optimization Designs in Downlink NOMA Transmission Systems

Abstract

To further balance the high-capacity transmission requirement and the scarce spectrum resources status quo, we investigate the joint optimization of energy efficiency (EE) and spectral efficiency (SE) in a downlink multiuser NOMA system. While ensuring the user quality of service (QoS), a power allocation algorithm based on two-layer optimization is proposed by transforming the original multiobjective optimization problem into a univariate problem through the linear weighted sum method. Based on the optimal user power allocation coefficient solution obtained from the inner layer, the outer layer applies the bisection principle to search for the optimal system transmit power according to the uniqueness of the maximum value of pseudo-concave functions. Simulation results show that the proposed algorithm always converges within fewer iterations and can achieve the flexible tradeoff between EE and SE. This is of great significance for improving the energy utilization of actual scenarios with time-varying communication demands.