Energy Efficiency Analysis of a SWIPT Enable Cooperative NOMA Communication System with the Presence of Eavesdropper

In this paper， we consider a simultaneous wireless information and power transfer （SWIPT） enable cooperative non-orthogonal multiple access （NOMA） communication system with the presence of eavesdropper， and then propose a multidimensional resource allocation scheme maximizing the energy efficiency of the far user. A multidimensional resource allocation problem to maximize energy efficiency of far users is established by jointly optimizing the transmitting power of the source node and near user as well as the energy collection time， subject to the energy-causality constraint and the safe transmission rate of the near users. As the formulated objective function is a fractional function， and includes couplings among optimization variables， it is non-convex and can not be solved by the existing convex tools. Therefore， we leverage the Dinkelbach method to transform the original problem into a convex optimization problem. On this basis， we propose an alternate iteration algorithm to solute this optimization problem. Finally， computer simulations verify the superiority of the proposed resource allocation method in terms of the energy efficiency of the remote user.