Secure UAV communication against cooperative adaptive eavesdroppers

The flexibility of the adaptive eavesdropper (AE) who can act as a passive eavesdropper or active jammer adaptively makes the attack mode more powerful, which will bring new security threats for unmanned aerial vehicle (UAV) communications. In this paper, we investigate secure UAV communications under multiple cooperative AEs. A cooperative attack game (CAG) is proposed to get the optimal joint attack action of multiple AEs according to the position of the aerial base station (ABS) and the Nash equilibrium (NE) point of CAG exist by proving the game as an exact potential game with at least one NE. Then, a Stackelberg game is applied to derive the ABS’s optimal position based on its own sensing according to AEs’ joint attack action by constructing the interactions between ABS and multiple AEs. Finally, a hierarchical learning algorithm is proposed to optimize the ABS’s position for enhancing the secrecy rate under the cooperative AEs. The simulation results show that the secrecy performance can be degraded severely by the cooperative AEs, and the ABS’s position promotes the enhancement of secrecy rate greatly within reasonable iteration times.