1,751 research outputs found
Empirical and Strong Coordination via Soft Covering with Polar Codes
We design polar codes for empirical coordination and strong coordination in
two-node networks. Our constructions hinge on the fact that polar codes enable
explicit low-complexity schemes for soft covering. We leverage this property to
propose explicit and low-complexity coding schemes that achieve the capacity
regions of both empirical coordination and strong coordination for sequences of
actions taking value in an alphabet of prime cardinality. Our results improve
previously known polar coding schemes, which (i) were restricted to uniform
distributions and to actions obtained via binary symmetric channels for strong
coordination, (ii) required a non-negligible amount of common randomness for
empirical coordination, and (iii) assumed that the simulation of discrete
memoryless channels could be perfectly implemented. As a by-product of our
results, we obtain a polar coding scheme that achieves channel resolvability
for an arbitrary discrete memoryless channel whose input alphabet has prime
cardinality.Comment: 14 pages, two-column, 5 figures, accepted to IEEE Transactions on
Information Theor
Strong Coordination with Polar Codes
In this paper, we design explicit codes for strong coordination in two-node
networks. Specifically, we consider a two-node network in which the action
imposed by nature is binary and uniform, and the action to coordinate is
obtained via a symmetric discrete memoryless channel. By observing that polar
codes are useful for channel resolvability over binary symmetric channels, we
prove that nested polar codes achieve a subset of the strong coordination
capacity region, and therefore provide a constructive and low complexity
solution for strong coordination.Comment: 7 pages doublespaced, presented at the 50th Annual Allerton
Conference on Communication, Control and Computing 201
Information Design for Strategic Coordination of Autonomous Devices with Non-Aligned Utilities
In this paper, we investigate the coordination of autonomous devices with
non-aligned utility functions. Both encoder and decoder are considered as
players, that choose the encoding and the decoding in order to maximize their
long-run utility functions. The topology of the point-to-point network under
investigation, suggests that the decoder implements a strategy, knowing in
advance the strategy of the encoder. We characterize the encoding and decoding
functions that form an equilibrium, by using empirical coordination. The
equilibrium solution is related to an auxiliary game in which both players
choose some conditional distributions in order to maximize their expected
utilities. This problem is closely related to the literature on "Information
Design" in Game Theory. We also characterize the set of posterior distributions
that are compatible with a rate-limited channel between the encoder and the
decoder. Finally, we provide an example of non-aligned utility functions
corresponding to parallel fading multiple access channels.Comment: IEEE Proc. of the Fifty-fourth Annual Allerton Conference Allerton
House, UIUC, Illinois, USA September 27 - 30, 201
Source-channel coding for coordination over a noisy two-node network
Recently, the concept of coordinating actions between distributed agents has emerged in the information theory literature. It was first introduced by Cuff in 2008 for the point-to-point case of coordination. However, Cuff’s work and the vast majority of the follow-up research are based on establishing coordination over noise-free communication links. In contrast, this thesis investigates the open problem of coordination over noisy point-to-point links. The aim of this study is to examine Shannon’s source-channel separation theorem in the context of coordination. To that end, a general joint scheme to achieve the strong notion of coordination over a discrete memoryless channel is introduced. The strong coordination notion requires that the L1 distance between the induced joint distribution of action sequences selected by the nodes and a prescribed joint distribution vanishes exponentially fast with the sequence block length. From the general joint scheme, three special cases are constructed, one of which resembles Shannon’s separation scheme. As a surprising result, the proposed joint scheme has been found to be able to perform better than a strictly separate scheme. Finally, the last part of the thesis provides simulation results to confirm the presented argument based on comparing the achievable rate regions for the scheme resembling Shannon’s separation and a special case of the general joint scheme
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
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