293 research outputs found
Artificial-Noise-Aided Secure Multi-Antenna Transmission with Limited Feedback
We present an optimized secure multi-antenna transmission approach based on
artificial-noise-aided beamforming, with limited feedback from a desired
single-antenna receiver. To deal with beamformer quantization errors as well as
unknown eavesdropper channel characteristics, our approach is aimed at
maximizing throughput under dual performance constraints - a connection outage
constraint on the desired communication channel and a secrecy outage constraint
to guard against eavesdropping. We propose an adaptive transmission strategy
that judiciously selects the wiretap coding parameters, as well as the power
allocation between the artificial noise and the information signal. This
optimized solution reveals several important differences with respect to
solutions designed previously under the assumption of perfect feedback. We also
investigate the problem of how to most efficiently utilize the feedback bits.
The simulation results indicate that a good design strategy is to use
approximately 20% of these bits to quantize the channel gain information, with
the remainder to quantize the channel direction, and this allocation is largely
insensitive to the secrecy outage constraint imposed. In addition, we find that
8 feedback bits per transmit antenna is sufficient to achieve approximately 90%
of the throughput attainable with perfect feedback.Comment: to appear in IEEE Transactions on Wireless Communication
Secure Transmission for Relay Wiretap Channels in the Presence of Spatially Random Eavesdroppers
We propose a secure transmission scheme for a relay wiretap channel, where a
source communicates with a destination via a decode-and-forward relay in the
presence of spatially random-distributed eavesdroppers. We assume that the
source is equipped with multiple antennas, whereas the relay, the destination,
and the eavesdroppers are equipped with a single antenna each. In the proposed
scheme, in addition to information signals, the source transmits artificial
noise signals in order to confuse the eavesdroppers. With the target of
maximizing the secrecy throughput of the relay wiretap channel, we derive a
closed-form expression for the transmission outage probability and an
easy-to-compute expression for the secrecy outage probability. Using these
expressions, we determine the optimal power allocation factor and wiretap code
rates that guarantee the maximum secrecy throughput, while satisfying a secrecy
outage probability constraint. Furthermore, we examine the impact of source
antenna number on the secrecy throughput, showing that adding extra transmit
antennas at the source brings about a significant increase in the secrecy
throughput.Comment: 7 pages, 5 figures, accepted by IEEE Globecom 2015 Workshop on
Trusted Communications with Physical Layer Securit
Optimal Number of Transmit Antennas for Secrecy Enhancement in Massive MIMOME Channels
This paper studies the impact of transmit antenna selection on the secrecy
performance of massive MIMO wiretap channels. We consider a scenario in which a
multi-antenna transmitter selects a subset of transmit antennas with the
strongest channel gains. Confidential messages are then transmitted to a
multi-antenna legitimate receiver while the channel is being overheard by a
multi-antenna eavesdropper. For this setup, we approximate the distribution of
the instantaneous secrecy rate in the large-system limit. The approximation
enables us to investigate the optimal number of selected antennas which
maximizes the asymptotic secrecy throughput of the system. We show that
increasing the number of selected antennas enhances the secrecy performance of
the system up to some optimal value, and that further growth in the number of
selected antennas has a destructive effect. Using the large-system
approximation, we obtain the optimal number of selected antennas analytically
for various scenarios. Our numerical investigations show an accurate match
between simulations and the analytic results even for not so large dimensions.Comment: 6 pages, 4 figures, IEEE GLOBECOM 201
Principles of Physical Layer Security in Multiuser Wireless Networks: A Survey
This paper provides a comprehensive review of the domain of physical layer
security in multiuser wireless networks. The essential premise of
physical-layer security is to enable the exchange of confidential messages over
a wireless medium in the presence of unauthorized eavesdroppers without relying
on higher-layer encryption. This can be achieved primarily in two ways: without
the need for a secret key by intelligently designing transmit coding
strategies, or by exploiting the wireless communication medium to develop
secret keys over public channels. The survey begins with an overview of the
foundations dating back to the pioneering work of Shannon and Wyner on
information-theoretic security. We then describe the evolution of secure
transmission strategies from point-to-point channels to multiple-antenna
systems, followed by generalizations to multiuser broadcast, multiple-access,
interference, and relay networks. Secret-key generation and establishment
protocols based on physical layer mechanisms are subsequently covered.
Approaches for secrecy based on channel coding design are then examined, along
with a description of inter-disciplinary approaches based on game theory and
stochastic geometry. The associated problem of physical-layer message
authentication is also introduced briefly. The survey concludes with
observations on potential research directions in this area.Comment: 23 pages, 10 figures, 303 refs. arXiv admin note: text overlap with
arXiv:1303.1609 by other authors. IEEE Communications Surveys and Tutorials,
201
Secure Communication with a Wireless-Powered Friendly Jammer
In this paper, we propose to use a wireless-powered friendly jammer to enable
secure communication between a source node and destination node, in the
presence of an eavesdropper. We consider a two-phase communication protocol
with fixed-rate transmission. In the first phase, wireless power transfer is
conducted from the source to the jammer. In the second phase, the source
transmits the information-bearing signal under the protection of a jamming
signal sent by the jammer using the harvested energy in the first phase. We
analytically characterize the long-time behavior of the proposed protocol and
derive a closed-form expression for the throughput. We further optimize the
rate parameters for maximizing the throughput subject to a secrecy outage
probability constraint. Our analytical results show that the throughput
performance differs significantly between the single-antenna jammer case and
the multi-antenna jammer case. For instance, as the source transmit power
increases, the throughput quickly reaches an upper bound with single-antenna
jammer, while the throughput grows unbounded with multi-antenna jammer. Our
numerical results also validate the derived analytical results.Comment: accepted for publication in IEEE Transactions on Wireless
Communication
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