2 research outputs found
State Amplification Subject To Masking Constraints
This paper considers a state dependent broadcast channel with one
transmitter, Alice, and two receivers, Bob and Eve. The problem is to
effectively convey ("amplify") the channel state sequence to Bob while
"masking" it from Eve. The extent to which the state sequence cannot be masked
from Eve is referred to as leakage. This can be viewed as a secrecy problem,
where we desire that the channel state itself be minimally leaked to Eve while
being communicated to Bob. The paper is aimed at characterizing the trade-off
region between amplification and leakage rates for such a system. An achievable
coding scheme is presented, wherein the transmitter transmits a partial state
information over the channel to facilitate the amplification process. For the
case when Bob observes a stronger signal than Eve, the achievable coding scheme
is enhanced with secure refinement. Outer bounds on the trade-off region are
also derived, and used in characterizing some special case results. In
particular, the optimal amplification-leakage rate difference, called as
differential amplification capacity, is characterized for the reversely
degraded discrete memoryless channel, the degraded binary, and the degraded
Gaussian channels. In addition, for the degraded Gaussian model, the extremal
corner points of the trade-off region are characterized, and the gap between
the outer bound and achievable rate-regions is shown to be less than half a bit
for a wide set of channel parameters.Comment: Revised versio
Joint Empirical Coordination of Source and Channel
In a decentralized and self-configuring network, the communication devices
are considered as autonomous decision-makers that sense their environment and
that implement optimal transmission schemes. It is essential that these
autonomous devices cooperate and coordinate their actions, to ensure the
reliability of the transmissions and the stability of the network. We study a
point-to-point scenario in which the encoder and the decoder implement
decentralized policies that are coordinated. The coordination is measured in
terms of empirical frequency of symbols of source and channel. The encoder and
the decoder perform a coding scheme such that the empirical distribution of the
symbols is close to a target joint probability distribution. We characterize
the set of achievable target probability distributions for a point-to-point
source-channel model, in which the encoder is non-causal and the decoder is
strictly causal i.e., it returns an action based on the observation of the past
channel outputs. The objectives of the encoder and of the decoder, are captured
by some utility function, evaluated with respect to the set of achievable
target probability distributions. In this article, we investigate the
maximization problem of a utility function that is common to both encoder and
decoder. We show that the compression and the transmission of information are
particular cases of the empirical coordination.Comment: accepted to IEEE Trans. on I