624 research outputs found
UAV Swarm-Enabled Aerial CoMP: A Physical Layer Security Perspective
Unlike aerial base station enabled by a single unmanned aerial vehicle (UAV),
aerial coordinated multiple points (CoMP) can be enabled by a UAV swarm. In
this case, the management of multiple UAVs is important. This paper considers
the power allocation strategy for a UAV swarm-enabled aerial network to enhance
the physical layer security of the downlink transmission, where an eavesdropper
moves following the trajectory of the swarm for better eavesdropping. Unlike
existing works, we use only the large-scale channel state information (CSI) and
maximize the secrecy throughput in a whole-trajectory-oriented manner. The
overall transmission energy constraint on each UAV and the total transmission
duration for all the legitimate users are considered. The non-convexity of the
formulated problem is solved by using max-min optimization with iteration. Both
the transmission power of desired signals and artificial noise (AN) are derived
iteratively. Simulation results are presented to validate the effectiveness of
our proposed power allocation algorithm and to show the advantage of aerial
CoMP by using only the large-scale CSI
Securing UAV Communications Via Trajectory Optimization
Unmanned aerial vehicle (UAV) communications has drawn significant interest
recently due to many advantages such as low cost, high mobility, and on-demand
deployment. This paper addresses the issue of physical-layer security in a UAV
communication system, where a UAV sends confidential information to a
legitimate receiver in the presence of a potential eavesdropper which are both
on the ground. We aim to maximize the secrecy rate of the system by jointly
optimizing the UAV's trajectory and transmit power over a finite horizon. In
contrast to the existing literature on wireless security with static nodes, we
exploit the mobility of the UAV in this paper to enhance the secrecy rate via a
new trajectory design. Although the formulated problem is non-convex and
challenging to solve, we propose an iterative algorithm to solve the problem
efficiently, based on the block coordinate descent and successive convex
optimization methods. Specifically, the UAV's transmit power and trajectory are
each optimized with the other fixed in an alternating manner until convergence.
Numerical results show that the proposed algorithm significantly improves the
secrecy rate of the UAV communication system, as compared to benchmark schemes
without transmit power control or trajectory optimization.Comment: Accepted by IEEE GLOBECOM 201
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
Robust Resource Allocation to Secure Physical Layer Using UAV-Assisted Mobile Relay Communications in 5G Technology
The unmanned aerial vehicles (UAVs) are also known as drones. Recently, UAVs have attracted the next generation researchers due to their flexible, dynamic, and cost-effective deployment, etc. Moreover, the UAVs have a wide range of application domains, such as rescue operation in the remote area, military surveillance, emergency application, etc. Given the UAVs are appropriately deployed, the UAVs provide continuous and reliable connectivity, on-demand, and cost-effective features to the desired destination in the wireless communication system. Thus, the UAVs can be a great choice to deploy as a mobile relay in co-existence with the base stations (BSs) on the ground to serve the 5G wireless users. In this thesis, the UAV-assisted mobile relay (UAV-MR) in the next generation wireless networks has been studied, which also considers the UAV-MR physical layer security. The proposed system also considers one ground user, one BS on the ground, and active presence of multiple eavesdroppers, situated nearby the ground user. The locations of these nodes (i.e., the ground user, the BS, and the eavesdroppers) are considered fixed on the ground. Moreover, the locations of the eavesdroppers are not precisely known to the UAV-MR. Thus, this thesis aims to maximize the achievable secrecy rate, while the BS sends the secure information to the ground user via the UAV-MR. However, the UAV-MR has some challenges to deploy in wireless networks, such as 3D deployment, robust resource allocation, secure UAV-MR to ground communication, the channel modeling, the UAV-MR flight duration, and the UAV-MR robust trajectory design, etc. Thus, this project investigates the UAV-MR assisted wireless networks, which addresses those technical challenges to guarantee efficient UAV-MR communication. Moreover, the mathematical frameworks are formulated to support the proposed model. An efficient algorithm is proposed to maximize the UAV-MR achievable secrecy rate. Finally, the simulation results show the improved performance for the UAV-MR assisted next-generation networks
Covert Communication in UAV-Assisted Air-Ground Networks
Unmanned aerial vehicle (UAV) assisted communication is a promising technique for future wireless networks due to its characteristics of low cost and flexible deployment. However, the high possibility of line-of-sight (LoS) air-ground channels may result in a great risk of being attacked by malicious users. Especially compared to the encryption and physical layer security that prevent eavesdropping, covert communication aims at hiding the existence of transmission, which is able to satisfy the more critical requirement of security. Thus, in this article, we focus on the covert communication issues of UAV-assisted wireless networks. First, the preliminaries of secure communications including encryption, physical layer security and covert communication are discussed. Then, current works and typical applications of UAV in covert communications are demonstrated. We then propose two schemes to enhance the covertness of UAV-assisted networks for some typical scenarios. Specifically, to improve the covert rate in UAV-assisted data dissemination, an iterative algorithm is proposed to jointly optimize the time slot, transmit power and trajectory. For the covertness of ground-air communication, a friendly jammer is employed to confuse the wardens, where the location of the jammer, the jamming power and the legitimate transmit power are jointly optimized. Numerical results are presented to validate the performance of these two proposed schemes. Finally, several challenges and promising directions are pointed out
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