Power Allocation for Proactive Eavesdropping with Spoofing Relay in UAV Systems

Unmanned aerial vehicles (UAVs) are used in legitimate surveillance systems. In this paper, we consider a wireless monitor system that consists of three UAVs. One UAV acts as a legitimate eavesdropper that adopts 1) spoofing relaying and 2) proactive eavesdropping via jamming techniques. In particular, two scenarios are considered if the legitimate eavesdropper has enough power for successful eavesdropping throughout flight time. If the legitimate eavesdropper has enough power, the formulated problem is a convex optimization problem, which can be solved by standard convex optimization techniques. If not, we formulate a non-convex optimization problem and solve it by an iterative algorithm. Numerical results show that the proposed power allocation scheme outperforms the passive eavesdropping and equally distributed jamming power allocation schemes.