6,032 research outputs found
Lecture Notes on Network Information Theory
These lecture notes have been converted to a book titled Network Information
Theory published recently by Cambridge University Press. This book provides a
significantly expanded exposition of the material in the lecture notes as well
as problems and bibliographic notes at the end of each chapter. The authors are
currently preparing a set of slides based on the book that will be posted in
the second half of 2012. More information about the book can be found at
http://www.cambridge.org/9781107008731/. The previous (and obsolete) version of
the lecture notes can be found at http://arxiv.org/abs/1001.3404v4/
Asymptotic Estimates in Information Theory with Non-Vanishing Error Probabilities
This monograph presents a unified treatment of single- and multi-user
problems in Shannon's information theory where we depart from the requirement
that the error probability decays asymptotically in the blocklength. Instead,
the error probabilities for various problems are bounded above by a
non-vanishing constant and the spotlight is shone on achievable coding rates as
functions of the growing blocklengths. This represents the study of asymptotic
estimates with non-vanishing error probabilities.
In Part I, after reviewing the fundamentals of information theory, we discuss
Strassen's seminal result for binary hypothesis testing where the type-I error
probability is non-vanishing and the rate of decay of the type-II error
probability with growing number of independent observations is characterized.
In Part II, we use this basic hypothesis testing result to develop second- and
sometimes, even third-order asymptotic expansions for point-to-point
communication. Finally in Part III, we consider network information theory
problems for which the second-order asymptotics are known. These problems
include some classes of channels with random state, the multiple-encoder
distributed lossless source coding (Slepian-Wolf) problem and special cases of
the Gaussian interference and multiple-access channels. Finally, we discuss
avenues for further research.Comment: Further comments welcom
Fundamental rate-loss tradeoff for optical quantum key distribution
Since 1984, various optical quantum key distribution (QKD) protocols have
been proposed and examined. In all of them, the rate of secret key generation
decays exponentially with distance. A natural and fundamental question is then
whether there are yet-to-be discovered optical QKD protocols (without quantum
repeaters) that could circumvent this rate-distance tradeoff. This paper
provides a major step towards answering this question. We show that the
secret-key-agreement capacity of a lossy and noisy optical channel assisted by
unlimited two-way public classical communication is limited by an upper bound
that is solely a function of the channel loss, regardless of how much optical
power the protocol may use. Our result has major implications for understanding
the secret-key-agreement capacity of optical channels---a long-standing open
problem in optical quantum information theory---and strongly suggests a real
need for quantum repeaters to perform QKD at high rates over long distances.Comment: 9+4 pages, 3 figures. arXiv admin note: text overlap with
arXiv:1310.012
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