5,222 research outputs found
Construction of Slepian-Wolf Source Code and Broadcast Channel Code Based on Hash Property
The aim of this paper is to prove theorems for the Slepian-Wolf source coding
and the broadcast channel coding (independent messages and no common message)
based on the the notion of a stronger version of the hash property for an
ensemble of functions. Since an ensemble of sparse matrices has a strong hash
property, codes using sparse matrices can realize the achievable rate region.
Furthermore, extensions to the multiple source coding and multiple output
broadcast channel coding are investigated.Comment: The proofs of Lemmas 4 and 9 are revised. Some proofs are simplified.
Some typos are fixed. A part of this paper has been published in Proceedings
of 2010 IEEE International Symposium on Information Theory (ISIT2010) and
Proceedings of 7th Asia-Europe Workshop "CONCEPTS in INFORMATION THEORY"
(AEW7), 2011, 39 page
Construction of Multiple Access Channel Codes Based on Hash Property
The aim of this paper is to introduce the construction of codes for a general
discrete stationary memoryless multiple access channel based on the the notion
of the hash property. Since an ensemble of sparse matrices has a hash property,
we can use sparse matrices for code construction. Our approach has a potential
advantage compared to the conventional random coding because it is expected
that we can use some approximation algorithms by using the sparse structure of
codes.Comment: This paper has been presented in part at Proc. 2011 IEEE Internal
Symposium on Information Theory and submitted to IEEE Transactions on
Information Theory. 39 page
Information-theoretic Physical Layer Security for Satellite Channels
Shannon introduced the classic model of a cryptosystem in 1949, where Eve has
access to an identical copy of the cyphertext that Alice sends to Bob. Shannon
defined perfect secrecy to be the case when the mutual information between the
plaintext and the cyphertext is zero. Perfect secrecy is motivated by
error-free transmission and requires that Bob and Alice share a secret key.
Wyner in 1975 and later I.~Csisz\'ar and J.~K\"orner in 1978 modified the
Shannon model assuming that the channels are noisy and proved that secrecy can
be achieved without sharing a secret key. This model is called wiretap channel
model and secrecy capacity is known when Eve's channel is noisier than Bob's
channel.
In this paper we review the concept of wiretap coding from the satellite
channel viewpoint. We also review subsequently introduced stronger secrecy
levels which can be numerically quantified and are keyless unconditionally
secure under certain assumptions. We introduce the general construction of
wiretap coding and analyse its applicability for a typical satellite channel.
From our analysis we discuss the potential of keyless information theoretic
physical layer security for satellite channels based on wiretap coding. We also
identify system design implications for enabling simultaneous operation with
additional information theoretic security protocols
Channel Coding and Lossy Source Coding Using a Constrained Random Number Generator
Stochastic encoders for channel coding and lossy source coding are introduced
with a rate close to the fundamental limits, where the only restriction is that
the channel input alphabet and the reproduction alphabet of the lossy source
code are finite. Random numbers, which satisfy a condition specified by a
function and its value, are used to construct stochastic encoders. The proof of
the theorems is based on the hash property of an ensemble of functions, where
the results are extended to general channels/sources and alternative formulas
are introduced for channel capacity and the rate-distortion region. Since an
ensemble of sparse matrices has a hash property, we can construct a code by
using sparse matrices, where the sum-product algorithm can be used for encoding
and decoding by assuming that channels/sources are memoryless.Comment: submitted to IEEE Transactions on Information Theory, 42 page
Construction of Codes for Wiretap Channel and Secret Key Agreement from Correlated Source Outputs by Using Sparse Matrices
The aim of this paper is to prove coding theorems for the wiretap channel
coding problem and secret key agreement problem based on the the notion of a
hash property for an ensemble of functions. These theorems imply that codes
using sparse matrices can achieve the optimal rate. Furthermore, fixed-rate
universal coding theorems for a wiretap channel and a secret key agreement are
also proved.Comment: A part of this paper is presented in part at 2009 IEEE Information
Theory Workshop (ITW2009), Taormina, Italy, pp.105-109, 2009. This paper is
submitted to IEEE Transactions on Information Theory. 34 page
Construction of wiretap codes from ordinary channel codes
From an arbitrary given channel code over a discrete or Gaussian memoryless
channel, we construct a wiretap code with the strong security. Our construction
can achieve the wiretap capacity under mild assumptions. The key tool is the
new privacy amplification theorem bounding the eavesdropped information in
terms of the Gallager function.Comment: 5 pages, no figure, IEEEtran.cls. Submitted to 2010 IEEE ISI
Polar Coding for Secure Transmission and Key Agreement
Wyner's work on wiretap channels and the recent works on information
theoretic security are based on random codes. Achieving information theoretical
security with practical coding schemes is of definite interest. In this note,
the attempt is to overcome this elusive task by employing the polar coding
technique of Ar{\i}kan. It is shown that polar codes achieve non-trivial
perfect secrecy rates for binary-input degraded wiretap channels while enjoying
their low encoding-decoding complexity. In the special case of symmetric main
and eavesdropper channels, this coding technique achieves the secrecy capacity.
Next, fading erasure wiretap channels are considered and a secret key agreement
scheme is proposed, which requires only the statistical knowledge of the
eavesdropper channel state information (CSI). The enabling factor is the
creation of advantage over Eve, by blindly using the proposed scheme over each
fading block, which is then exploited with privacy amplification techniques to
generate secret keys.Comment: Proceedings of the 21st Annual IEEE International Symposium on
Personal, Indoor, and Mobile Radio Communications (PIMRC 2010), Sept. 2010,
Istanbul, Turke
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