Unmanned aerial vehicles (UAVs) can provide wireless access services to
terrestrial users without geographical limitations and will become an essential
part of the future communication system. However, the openness of wireless
channels and the mobility of UAVs make the security of UAV-based communication
systems particularly challenging. This work investigates the security of aerial
cognitive radio networks (CRNs) with multiple uncertainties colluding
eavesdroppers. A cognitive aerial base station transmits messages to cognitive
terrestrial users using the spectrum resource of the primary users. All
secondary terrestrial users and illegitimate receivers jointly decode the
received message. The average secrecy rate of the aerial CRNs is maximized by
jointly optimizing the UAV's trajectory and transmission power. An iterative
algorithm based on block coordinate descent and successive convex approximation
is proposed to solve the non-convex mixed-variable optimization problem.
Numerical results verify the effectiveness of our proposed algorithm and show
that our scheme improves the secrecy performance of airborne CRNs.Comment: 10 pages, 7 figures.submitted to the IEEE journal for revie