This article studies the secure communication of a non-orthogonal multiple access (NOMA) system with the help of an unmanned aerial vehicle (UAV). The UAV flies from an initial location to a final location and assists the NOMA communication between terrestrial nodes, including a source, a near user, and a far user, in the presence of an eavesdropper. Artificial noise (AN) is inserted into the transmitted signal of the UAV to enable secure communication for the users. To maximize the system secrecy sum-rate (SSSR), an algorithm is proposed to optimize key system parameters, such as the UAV’s trajectory, the power–allocation factors, and the transmit powers of the source and the UAV. Since the objective function of the SSSR maximization problem is non-convex, the successive convex optimization (SCO) and block coordinate descent (BCD) methods are applied to find efficient approximate solutions. The effectiveness of the proposed algorithms is confirmed by simulation results.

本文研究了在无人机 (UAV) 的帮助下非正交多址 (NOMA) 系统的安全通信。无人机从初始位置飞行到最终位置，并在窃听者存在的情况下协助地面节点（包括源、近端用户和远端用户）之间的 NOMA 通信。人工噪声（AN）被插入到无人机的传输信号中，以实现用户的安全通信。为了最大化系统保密和速率（SSSR），提出了一种算法来优化关键系统参数，例如无人机的轨迹、功率分配因素以及源和无人机的发射功率。由于SSSR最大化问题的目标函数是非凸的，连续凸优化 (SCO) 和块坐标下降 (BCD) 方法用于寻找有效的近似解。仿真结果证实了所提出算法的有效性。