IEEE International Conference on Communication Technology (ICCT)
Physical Layer Security Enhancement Techniques for UAV Relay Systems Based on Artificial Noise Assistance
Yunqi Hao, Youyang Xiang, Xianglu Li, Chen Ding, Qilong Du, Dong Hou, Jie Tian
Abstract
The broadcast nature of wireless channels introduces significant security risks during information transmission. When the eavesdropper is in close proximity to the legitimate receiver, their channel state information (CSI) may be highly correlated or even superior to that of the legitimate channel, rendering traditional power optimization methods ineffective in suppressing eavesdropping rates. To address this issue, this paper proposes an artificial noise (AN)-assisted unmanned aerial vehicle (UAV) relay system. By leveraging the UAV relay to inject artificial noise while transmitting signals and dynamically adjusting the power allocation factor based on real-time CSI and the UAV's position, precise interference control over the eavesdropping channel is achieved. This study establishes a fournode communication system comprising a source, relay, legitimate receiver, and eavesdropper, formulating a joint optimization problem aimed at maximizing secrecy capacity. Given the nonconvex nature of the optimization problem, this paper employs slack variables and the successive convex approximation (SCA) method to equivalently transform the original problem into a convex problem. A closed-form analytical solution for the power allocation factor is derived using the staircase water-filling (WF) algorithm. Furthermore, an alternating iterative optimization algorithm based on artificial noise assistance is proposed to achieve global optimization of system parameters. Simulation results demonstrate that, compared to traditional power optimization schemes, the proposed algorithm reduces the eavesdropping capacity and improves the information transmission efficiency, significantly enhancing both system security and transmission performance.