5 research outputs found
Wireless Physical Layer Security with Imperfect Channel State Information: A Survey
Physical layer security is an emerging technique to improve the wireless
communication security, which is widely regarded as a complement to
cryptographic technologies. To design physical layer security techniques under
practical scenarios, the uncertainty and imperfections in the channel knowledge
need to be taken into consideration. This paper provides a survey of recent
research and development in physical layer security considering the imperfect
channel state information (CSI) at communication nodes. We first present an
overview of the main information-theoretic measures of the secrecy performance
with imperfect CSI. Then, we describe several signal processing enhancements in
secure transmission designs, such as secure on-off transmission, beamforming
with artificial noise, and secure communication assisted by relay nodes or in
cognitive radio systems. The recent studies of physical layer security in
large-scale decentralized wireless networks are also summarized. Finally, the
open problems for the on-going and future research are discussed
MIMO Multiple Access Channel with an Arbitrarily Varying Eavesdropper
A two-transmitter Gaussian multiple access wiretap channel with multiple
antennas at each of the nodes is investigated. The channel matrices at the
legitimate terminals are fixed and revealed to all the terminals, whereas the
channel matrix of the eavesdropper is arbitrarily varying and only known to the
eavesdropper. The secrecy degrees of freedom (s.d.o.f.) region under a strong
secrecy constraint is characterized. A transmission scheme that orthogonalizes
the transmit signals of the two users at the intended receiver and uses a
single-user wiretap code is shown to be sufficient to achieve the s.d.o.f.
region. The converse involves establishing an upper bound on a
weighted-sum-rate expression. This is accomplished by using induction, where at
each step one combines the secrecy and multiple-access constraints associated
with an adversary eavesdropping a carefully selected group of sub-channels.Comment: submitted to IEEE Transactions on Information on 02/24/2012. The
ordering of authors is alphabetica
Strong Secrecy in Pairwise Key Agreement over a Generalized Multiple Access Channel
This paper considers the problem of pairwise key agreement without public
communication between three users connected through a generalized multiple
access channel (MAC). While two users control the channel inputs, all three
users observe noisy outputs from the channel and each pair of users wishes to
agree on a secret key hidden from the remaining user. We first develop a
"pre-generated" key-agreement scheme based on secrecy codes for the generalized
MAC, in which the channel is only used to distribute pre-generated secret keys.
We then extend this scheme to include an additional layer of rate-limited
secret-key generation by treating the observed channel outputs as induced
sources. We characterize inner and outer bounds on the strong secret-key
capacity region for both schemes. For a special case of the "pre-generated"
scheme, we obtain an exact characterization. We also illustrate with some
binary examples that exploiting the generalized nature of the generalized MAC
may lead to significantly larger key-agreement rates.Comment: 45 pages, 11 figures, Submitted to the IEEE Transactions on
Information Theor
The Arbitrarily Varying Channel with Colored Gaussian Noise
We address the arbitrarily varying channel (AVC) with colored Gaussian noise.
The work consists of three parts. First, we study the general discrete AVC with
fixed parameters, where the channel depends on two state sequences, one
arbitrary and the other fixed and known. This model can be viewed as a
combination of the AVC and the time-varying channel. We determine both the
deterministic code capacity and the random code capacity. Super-additivity is
demonstrated, showing that the deterministic code capacity can be strictly
larger than the weighted sum of the parametric capacities.
In the second part, we consider the arbitrarily varying Gaussian product
channel (AVGPC). Hughes and Narayan characterized the random code capacity
through min-max optimization leading to a "double" water filling solution.
Here, we establish the deterministic code capacity and also discuss the
game-theoretic meaning and the connection between double water filling and Nash
equilibrium. As in the case of the standard Gaussian AVC, the deterministic
code capacity is discontinuous in the input constraint, and depends on which of
the input or state constraint is higher. As opposed to Shannon's classic water
filling solution, it is observed that deterministic coding using independent
scalar codes is suboptimal for the AVGPC.
Finally, we establish the capacity of the AVC with colored Gaussian noise,
where double water filling is performed in the frequency domain. The analysis
relies on our preceding results, on the AVC with fixed parameters and the
AVGPC.Comment: This is a replacement of a paper that was previously titled 'The
Water Filling Game', after a major revision. The current version, titled 'The
Arbitrarily Varying Channel with Colored Gaussian Noise' contains a lot more
results, better literature review, and detailed proof
GC'11 Workshop on Physical-Layer Security Gaussian Two-way Wiretap Channel with an Arbitrarily Varying Eavesdropper
Abstract—In this work, we derive the secrecy degrees of freedom (s.d.o.f.) region of the Gaussian two-way wiretap channel in which the eavesdropper channel state is arbitrarily varying and is unknown to the legitimate nodes. We prove that the s.d.o.f. region is identical to that when the eavesdropper channel is fixed and globally known. A multi-stage coding scheme that combines secret key generation and confidential message transmission is developed to prove achievability. The confidentiality guarantee provided in this work is in the sense of strong secrecy