Joint source-channel with side information coding error exponents

TL;DR

This paper investigates bounds on the error exponents for joint source-channel coding with decoder side-information, extending classical results and analyzing the impact of encoder side-information on error performance.

Contribution

It extends Csiszar's classical bounds to scenarios with decoder side-information and establishes conditions where bounds coincide, showing encoder side-information does not improve error exponents.

Findings

Bounds on error exponents are tight for certain channels.

Encoder side-information does not increase error exponents.

Existence of saddle points in a game-theoretic framework for symmetric channels.

Abstract

In this paper, we study the upper and the lower bounds on the joint source-channel coding error exponent with decoder side-information. The results in the paper are non-trivial extensions of the Csiszar's classical paper [5]. Unlike the joint source-channel coding result in [5], it is not obvious whether the lower bound and the upper bound are equivalent even if the channel coding error exponent is known. For a class of channels, including the symmetric channels, we apply a game-theoretic result to establish the existence of a saddle point and hence prove that the lower and upper bounds are the same if the channel coding error exponent is known. More interestingly, we show that encoder side-information does not increase the error exponents in this case.