98 research outputs found
Trajectory and Power Design for Aerial Multi-User Covert Communications
Unmanned aerial vehicles (UAVs) can provide wireless access to terrestrial
users, regardless of geographical constraints, and will be an important part of
future communication systems. In this paper, a multi-user downlink dual-UAVs
enabled covert communication system was investigated, in which a UAV transmits
secure information to ground users in the presence of multiple wardens as well
as a friendly jammer UAV transmits artificial jamming signals to fight with the
wardens. The scenario of wardens being outfitted with a single antenna is
considered, and the detection error probability (DEP) of wardens with finite
observations is researched. Then, considering the uncertainty of wardens'
location, a robust optimization problem with worst-case covertness constraint
is formulated to maximize the average covert rate by jointly optimizing power
allocation and trajectory. To cope with the optimization problem, an algorithm
based on successive convex approximation methods is proposed. Thereafter, the
results are extended to the case where all the wardens are equipped with
multiple antennas. After analyzing the DEP in this scenario, a tractable lower
bound of the DEP is obtained by utilizing Pinsker's inequality. Subsequently,
the non-convex optimization problem was established and efficiently coped by
utilizing a similar algorithm as in the single-antenna scenario. Numerical
results indicate the effectiveness of our proposed algorithm.Comment: 30 pages, 9 figures, submitted to the IEEE journal for revie
Clustered Jamming in Aerial HetNets with Decoupled Access
The tremendous increase in wireless connectivity demand will result in the degradation of the service quality and the scarcity of network capacity and coverage in the beyond 5 th generation era. To ensure reliable connectivity and enhance the network’s performance, the evolution of heterogeneous networks (HetNets) must incorporate aerial platforms in addition to traditional terrestrial base stations. The performance of Aerial-HetNets (A-HetNets) is largely dependent on the users’ association. The conventional user-association scheme based on downlink received power provides sub-optimal performance for the edge users. For this reason, decoupled user-association along with the reverse frequency allocation (RFA) strategy has been employed in A-HetNets. The performance of A-HetNets is also affected if wide-band jammers (WBJs) are present in the vicinity and impose jamming interference. In this paper, a two-tier A-HetNet with RFA and decoupled access is analyzed in the presence of jamming interference. The obtained results show that for a signal-to-interference ratio threshold of −20 dBm, the percentage decrease in the coverage probability of the decoupled access due to WBJ activity is up to 7.4%, 13.5%, and 19.7%, for the average number of WBJs equal to 2, 4, and 6, respectively. The performance of the decoupled access in A-HetNets is further decreased by increasing the transmit power of the WBJs while it is increased by increasing the radius of the WBJ’s cluster
Physical layer security against eavesdropping in the internet of drones (IoD) based communication systems
rones or unmanned aerial vehicles (UAVs) communication technology, which has recently been
thoroughly studied and adopted by 3GPP standard (Release 15) due to its dynamic, flexible, and flying
nature, is expected to be an integral part of future wireless communications and Internet of drones
(IoD) applications. However, due to the unique transmission characteristics and nature of UAV systems
including broadcasting, dominant line of site and poor scattering, providing confidentiality for legitimate
receivers against unintended ones (eavesdroppers) appears to be a challenging goal to achieve in such
scenarios. Besides, the special features of UAVs represented by having limited power (battery-operated)
and precessing (light RAM and CPU capabilities), makes applying complex cryptography approaches
very challenging and inefficient for such systems. This motives the utilization of alternative approaches
enabled by physical layer security (PLS) concept for securing UAV-based systems. Techniques based
on PLS are deemed to be promising due to their ability to provide inherent secrecy that is complexity independent, where no matter what computational processing power the eavesdropper may have, there
is no way to decrypt the PLS algorithms. This work is dedicated to highlight and overview the latest
advances and state of art researches on the field of applying PLS to UAV systems in a unified and
structured manner. Particularity, it discusses and explains the different, possible PLS scenarios and
use cases of UAVs, which are categorized based on how the drone is utilized and employed in the
communication system setup. The main classified categories include the deployment of the flying, mobile
UAV as a 1) base station (BS), 2) user equipment (UE), 2) relay, or 4) jammer. Then, recommendations
and future open research issues are stated and discussed.No sponso
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