Proactive Eavesdropping in Relay Systems via Trajectory and Power Optimization

Wireless relays can effectively extend the transmission range of information. However, if relay technology is utilized unlawfully, it can amplify potential harm. Effectively surveilling illegitimate relay links poses a challenging problem. Unmanned aerial vehicles (UAVs) can proactively surveil wireless relay systems due to their flexible mobility. This work focuses on maximizing the eavesdropping rate (ER) of UAVs by jointly optimizing the trajectory and jamming power. To address this challenge, we propose a new iterative algorithm based on block coordinate descent and successive convex approximation technologies. Simulation results demonstrate that the proposed algorithm significantly enhances the ER through trajectory and jamming power optimization.