3 research outputs found
Covert Surveillance via Proactive Eavesdropping Under Channel Uncertainty
Surveillance performance is studied for a wireless eavesdropping system,
where a full-duplex legitimate monitor eavesdrops a suspicious link efficiently
with the artificial noise (AN) assistance. Different from the existing work in
the literature, the suspicious receiver in this paper is assumed to be capable
of detecting the presence of AN. Once such receiver detects the AN, the
suspicious user will stop transmission, which is harmful for the surveillance
performance. Hence, to improve the surveillance performance, AN should be
transmitted covertly with a low detection probability by the suspicious
receiver. Under these assumptions, an optimization problem is formulated to
maximize the eavesdropping non-outage probability under a covert constraint.
Based on the detection ability at the suspicious receiver, a novel scheme is
proposed to solve the optimization problem by iterative search. Moreover, we
investigate the impact of both the suspicious link uncertainty and the jamming
link uncertainty on the covert surveillance performance. Simulations are
performed to verify the analyses. We show that the suspicious link uncertainty
benefits the surveillance performance, while the jamming link uncertainty can
degrade the surveillance performance.Comment: 28 pages, 10 figure
Energy Management and Trajectory Optimization for UAV-Enabled Legitimate Monitoring Systems
Thanks to their quick placement and high flexibility, unmanned aerial
vehicles (UAVs) can be very useful in the current and future wireless
communication systems. With a growing number of smart devices and
infrastructure-free communication networks, it is necessary to legitimately
monitor these networks to prevent crimes. In this paper, a novel framework is
proposed to exploit the flexibility of the UAV for legitimate monitoring via
joint trajectory design and energy management. The system includes a suspicious
transmission link with a terrestrial transmitter and a terrestrial receiver,
and a UAV to monitor the suspicious link. The UAV can adjust its positions and
send jamming signal to the suspicious receiver to ensure successful
eavesdropping. Based on this model, we first develop an approach to minimize
the overall jamming energy consumption of the UAV. Building on a judicious
(re-)formulation, an alternating optimization approach is developed to compute
a locally optimal solution in polynomial time. Furthermore, we model and
include the propulsion power to minimize the overall energy consumption of the
UAV. Leveraging the successive convex approximation method, an effective
iterative approach is developed to find a feasible solution fulfilling the
Karush-Kuhn-Tucker (KKT) conditions. Extensive numerical results are provided
to verify the merits of the proposed schemes.Comment: IEEE Transactions on Wireless Communications, revised, Apr. 202
Jamming-assisted Proactive Eavesdropping over Two Suspicious Communication Links
This paper studies a new and challenging wireless surveillance problem where
a legitimate monitor attempts to eavesdrop two suspicious communication links
simultaneously. To facilitate concurrent eavesdropping, our multi-antenna
legitimate monitor employs a proactive eavesdropping via jamming approach, by
selectively jamming suspicious receivers to lower the transmission rates of the
target links. In particular, we are interested in characterizing the achievable
eavesdropping rate region for the minimum-mean-squared-error (MMSE) receiver
case, by optimizing the legitimate monitor's jamming transmit covariance matrix
subject to its power budget. As the monitor cannot hear more than what
suspicious links transmit, the achievable eavesdropping rate region is
essentially the intersection of the achievable rate region for the two
suspicious links and that for the two eavesdropping links. The former region
can be purposely altered by the monitor's jamming transmit covariance matrix,
whereas the latter region is fixed when the MMSE receiver is employed.
Therefore, we first analytically characterize the achievable rate region for
the two suspicious links via optimizing the jamming transmit covariance matrix
and then obtain the achievable eavesdropping rate region for the MMSE receiver
case. Furthermore, we also extend our study to the MMSE with successive
interference cancellation (MMSE-SIC) receiver case and characterize the
corresponding achievable eavesdropping rate region by jointly optimizing the
time-sharing factor between different decoding orders. Finally, numerical
results are provided to corroborate our analysis and examine the eavesdropping
performance