107 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
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 on-off transmission design with channel estimation errors
Physical layer security has recently been regarded
as an emerging technique to complement and improve the
communication security in future wireless networks. The current
research and development in physical layer security are often
based on the ideal assumption of perfect channel knowledge or
the capability of variable-rate transmissions. In this paper, we
study the secure transmission design in more practical scenarios
by considering channel estimation errors at the receiver and
investigating both fixed-rate and variable-rate transmissions.
Assuming quasi-static fading channels, we design secure on-off
transmission schemes to maximize the throughput subject to
a constraint on secrecy outage probability. For systems with
given and fixed encoding rates, we show how the optimal on-off
transmission thresholds and the achievable throughput vary with
the amount of knowledge on the eavesdropper’s channel. In
particular, our design covers the interesting case where the
eavesdropper also uses the pilots sent from the transmitter to
obtain imperfect channel estimation. An interesting observation
is that using too much pilot power can harm the throughput
of secure transmission if both the legitimate receiver and the
eavesdropper have channel estimation errors, while the secure
transmission always benefits from increasing pilot power when
only the legitimate receiver has channel estimation errors but
not the eavesdropper. When the encoding rates are controllable
parameters to design, we further derive both a non-adaptive
and an adaptive rate transmission schemes by jointly optimizing
the encoding rates and the on-off transmission thresholds to
maximize the throughput of secure transmissions
A Versatile Secure Transmission Strategy in the Presence of Outdated CSI
We study secure transmission considering the practical scenario
where only outdated knowledge of the legitimate receiver’s channel
and statistical knowledge of the eavesdropper’s channel is available at
the transmitter. Conditioned on the limited channel knowledge, we adopt
an on-off secure transmission scheme and propose a versatile strategy to
determine the codeword transmission rate. We first analyze the outage
performance of the system and then provide the design of optimal wiretap
code parameters maximizing the secrecy throughput. Compared with
the existing solution in the literature, the proposed secure transmission
design enlarges the achievable reliability-security region and increases
the maximum secrecy throughput.ARC Discovery Projects Grant DP15010390
Power allocation and signal labelling on physical layer security
PhD ThesisSecure communications between legitimate users have received considerable
attention recently. Transmission cryptography, which introduces
secrecy on the network layer, is heavily relied on conventionally to secure
communications. However, it is theoretically possible to break the
encryption if unlimited computational resource is provided. As a result,
physical layer security becomes a hot topic as it provides perfect secrecy
from an information theory perspective. The study of physical layer
security on real communication system model is challenging and important,
as the previous researches are mainly focusing on the Gaussian
input model which is not practically implementable.
In this thesis, the physical layer security of wireless networks employing
finite-alphabet input schemes are studied. In particular, firstly, the secrecy
capacity of the single-input single-output (SISO) wiretap channel
model with coded modulation (CM) and bit-interleaved coded modulation
(BICM) is derived in closed-form, while a fast, sub-optimal power
control policy (PCP) is presented to maximize the secrecy capacity performance.
Since finite-alphabet input schemes achieve maximum secrecy
capacity at medium SNR range, the maximum amount of energy that
the destination can harvest from the transmission while satisfying the
secrecy rate constraint is computed. Secondly, the effects of mapping
techniques on secrecy capacity of BICM scheme are investigated, the secrecy
capacity performances of various known mappings are compared on
8PSK, 16QAM and (1,5,10) constellations, showing that Gray mapping
obtains lowest secrecy capacity value at high SNRs. We propose a new
mapping algorithm, called maximum error event (MEE), to optimize the
secrecy capacity over a wide range of SNRs. At low SNR, MEE mapping
achieves a lower secrecy rate than other well-known mappings, but
at medium-to-high SNRs MEE mapping achieves a significantly higher
secrecy rate over a wide range of SNRs. Finally, the secrecy capacity and
power allocation algorithm (PA) of finite-alphabet input wiretap channels
with decode-and-forward (DF) relays are proposed, the simulation
results are compared with the equal power allocation algorithm
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