Energy Efficient Resource Allocation for Time Switching Wireless Powered NOMA Networks

Non-orthogonal multiple access (NOMA) has attracted much attention from not only industry but also academia and has the potential to meet the demand of increasing data rate. In this paper, the problem of joint resource allocation and time switching (TS) control in wireless-powered NOMA internet of things (IoT) network is considered. We aim to maximize the sum of user-centric energy efficiency (EE) in the system. The optimization problem is divided into subcarrier allocation, power control and TS control. Firstly, the subcarrier allocation problem is a mixed-integer non-linear programming problem which is non-convex. Thus two-sided matching algorithm is proposed to optimize subcarrier allocation with low complexity. Then because the sum of user-centric EE is the sum of fractional programming problem, successive convex approximation (SCA) is applied to solve the problem. Finally, the simulation results show convergence of the proposed optimization scheme and we achieve better performance than orthogonal frequency division multiple access (OFDMA) scheme.