744 research outputs found
Trajectory and power design for aerial CRNs with colluding eavesdroppers
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
Security enhancement for NOMA-UAV networks
Owing to its distinctive merits, non-orthogonal multiple access (NOMA) techniques have been utilized in unmanned aerial vehicle (UAV) enabled wireless base stations to provide effective coverage for terrestrial users. However, the security of NOMA-UAV systems remains a challenge due to the line-of-sight air-to-ground channels and higher transmission power of weaker users in NOMA. In this paper, we propose two schemes to guarantee the secure transmission in UAV-NOMA networks. When only one user requires secure transmission, we derive the hovering position for the UAV and the power allocation to meet rate threshold of the secure user while maximizing the sum rate of remaining users. This disrupts the eavesdropping towards the secure user effectively. When multiple users require secure transmission, we further take the advantage of beamforming via multiple antennas at the UAV to guarantee their secure transmission. Due to the non-convexity of this problem, we convert it into a convex one for an iterative solution by using the second order cone programming. Finally, simulation results are provided to show the effectiveness of the proposed scheme
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