Joint Empirical Coordination of Source and Channel

TL;DR

This paper explores how autonomous communication devices can coordinate their actions in a decentralized network by achieving specific joint symbol distributions, optimizing a shared utility function.

Contribution

It characterizes the set of achievable joint distributions in a point-to-point source-channel model with decentralized policies and maximizes a common utility function.

Findings

Achievable distributions are characterized for non-causal encoder and strictly causal decoder.

The framework generalizes compression and transmission as special cases of empirical coordination.

Optimal policies can be designed to maximize shared utility in decentralized networks.

Abstract

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.