34 research outputs found
Secure Multiterminal Source Coding with Side Information at the Eavesdropper
The problem of secure multiterminal source coding with side information at
the eavesdropper is investigated. This scenario consists of a main encoder
(referred to as Alice) that wishes to compress a single source but
simultaneously satisfying the desired requirements on the distortion level at a
legitimate receiver (referred to as Bob) and the equivocation rate --average
uncertainty-- at an eavesdropper (referred to as Eve). It is further assumed
the presence of a (public) rate-limited link between Alice and Bob. In this
setting, Eve perfectly observes the information bits sent by Alice to Bob and
has also access to a correlated source which can be used as side information. A
second encoder (referred to as Charlie) helps Bob in estimating Alice's source
by sending a compressed version of its own correlated observation via a
(private) rate-limited link, which is only observed by Bob. For instance, the
problem at hands can be seen as the unification between the Berger-Tung and the
secure source coding setups. Inner and outer bounds on the so called
rates-distortion-equivocation region are derived. The inner region turns to be
tight for two cases: (i) uncoded side information at Bob and (ii) lossless
reconstruction of both sources at Bob --secure distributed lossless
compression. Application examples to secure lossy source coding of Gaussian and
binary sources in the presence of Gaussian and binary/ternary (resp.) side
informations are also considered. Optimal coding schemes are characterized for
some cases of interest where the statistical differences between the side
information at the decoders and the presence of a non-zero distortion at Bob
can be fully exploited to guarantee secrecy.Comment: 26 pages, 16 figures, 2 table
Binary CEO Problem under Log-Loss with BSC Test-Channel Model
In this paper, we propose an efficient coding scheme for the two-link binary
Chief Executive Officer (CEO) problem under logarithmic loss criterion. The
exact rate-distortion bound for a two-link binary CEO problem under the
logarithmic loss has been obtained by Courtade and Weissman. We propose an
encoding scheme based on compound LDGM-LDPC codes to achieve the theoretical
bounds. In the proposed encoding, a binary quantizer using LDGM codes and a
syndrome-coding employing LDPC codes are applied. An iterative joint decoding
is also designed as a fusion center. The proposed CEO decoder is based on the
sum-product algorithm and a soft estimator.Comment: 5 pages. arXiv admin note: substantial text overlap with
arXiv:1801.0043
Successive structuring of source coding algorithms for data fusion, buffering, and distribution in networks
Supervised by Gregory W. Wornell.Also issued as Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.Includes bibliographical references (p. 159-165).(cont.) We also explore the interactions between source coding and queue management in problems of buffering and distributing distortion-tolerant data. We formulate a general queuing model relevant to numerous communication scenarios, and develop a bound on the performance of any algorithm. We design an adaptive buffer-control algorithm for use in dynamic environments and under finite memory limitations; its performance closely approximates the bound. Our design uses multiresolution source codes that exploit the data's distortion-tolerance in minimizing end-to-end distortion. Compared to traditional approaches, the performance gains of the adaptive algorithm are significant - improving distortion, delay, and overall system robustness.by Stark Christiaan Draper
Distributed signal processing using nested lattice codes
Multi-Terminal Source Coding (MTSC) addresses the problem of compressing correlated sources
without communication links among them. In this thesis, the constructive approach of this problem
is considered in an algebraic framework and a system design is provided that can be applicable
in a variety of settings. Wyner-Ziv problem is first investigated: coding of an independent and
identically distributed (i.i.d.) Gaussian source with side information available only at the decoder
in the form of a noisy version of the source to be encoded. Theoretical models are first established
and derived for calculating distortion-rate functions. Then a few novel practical code implementations are proposed by using the strategy of multi-dimensional nested lattice/trellis coding. By
investigating various lattices in the dimensions considered, analysis is given on how lattice properties affect performance. Also proposed are methods on choosing good sublattices in multiple
dimensions. By introducing scaling factors, the relationship between distortion and scaling factor
is examined for various rates. The best high-dimensional lattice using our scale-rotate method can
achieve a performance less than 1 dB at low rates from the Wyner-Ziv limit; and random nested
ensembles can achieve a 1.87 dB gap with the limit. Moreover, the code design is extended to
incorporate with distributed compressive sensing (DCS). Theoretical framework is proposed and
practical design using nested lattice/trellis is presented for various scenarios. By using nested
trellis, the simulation shows a 3.42 dB gap from our derived bound for the DCS plus Wyner-Ziv
framework
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/
Beyond Transmitting Bits: Context, Semantics, and Task-Oriented Communications
Communication systems to date primarily aim at reliably communicating bit
sequences. Such an approach provides efficient engineering designs that are
agnostic to the meanings of the messages or to the goal that the message
exchange aims to achieve. Next generation systems, however, can be potentially
enriched by folding message semantics and goals of communication into their
design. Further, these systems can be made cognizant of the context in which
communication exchange takes place, providing avenues for novel design
insights. This tutorial summarizes the efforts to date, starting from its early
adaptations, semantic-aware and task-oriented communications, covering the
foundations, algorithms and potential implementations. The focus is on
approaches that utilize information theory to provide the foundations, as well
as the significant role of learning in semantics and task-aware communications.Comment: 28 pages, 14 figure