Secrecy Energy Efficiency Maximization in a NOMA System

In this paper, for the downlink of a non-orthogonal multiple access (NOMA) system, the power allocation scheme is proposed for the legitimate users. Attaching importance to the physical layer security and the green requirements of 5G, the secrecy energy efficiency (SEE) has first been defined. Then, we formulate an optimization problem, where each user's power allocation factor and total power allocation factor are determined. For reducing the computational complexity, we decouple the optimization problem into two concatenate subproblems and solve them one by one. Finally, some numerical results are presented to validate our proposed power allocation algorithm.