Abstract
Unmanned aerial vehicles (UAVs) equipped with visible light communication (VLC) have attracted growing interest due to their capability of providing simultaneous illumination and wireless connectivity in outdoor nighttime environments. However, VLC-UAV networks are inherently vulnerable to eavesdropping , making secure transmission a critical challenge. In this letter, we propose a cooperative jamming-enhanced secure VLC-UAV scheme that jointly ensures illumination, data rate requirements, and secure service fairness among all users. The secrecy enhancement problem is formulated as maximizing the average achievable secrecy rate through coordinated optimization of user association and VLC-UAVs' trajectories. To efficiently solve this mixed-integer non-convex problem, we delicately transform it into tractable convex forms and develop an iterative algorithm based on block coordinate descent and successive convex approximation. Numerical results verify that the proposed scheme achieves superior secrecy performance and robustness compared with existing benchmark methods. Index Terms—Cooperative jamming, physical layer security, unmanned aerial vehicle, visible light communication.