Empirical Coordination over Markov Channel with Independent Source
Mengyuan Zhao, Maël Le Treust, Tobias J. Oechtering
TL;DR
This work addresses empirical coordination for joint source–channel coding over Markov channels with strictly causal encoders and noncausal decoders. It derives single-letter inner and outer bounds on the achievable joint distribution by introducing an auxiliary variable $W$ and an information constraint $I(X;Y|Y') - I(U;W|X) \ge 0$, capturing how the encoder conveys compressed source information to the decoder under Markov memory. The analysis introduces input-driven Markov typicality, along with its AEP and packing properties, to exploit channel structure beyond independence-based arguments. The results generalize coordination coding beyond DMCs, and special cases recover Shannon-style source–channel separation when variables are independent, highlighting the framework's practical relevance for JSCC with memory.
Abstract
We study joint source-channel coding over Markov channels through the empirical coordination framework. More specifically, we aim at determining the empirical distributions of source and channel symbols that can be induced by a coding scheme. We consider strictly causal encoders that generate channel inputs, without access to the past channel states, henceforth driving the current Markov state evolution. Our main result is the single-letter inner and outer bounds of the set of achievable joint distributions, coordinating all the symbols in the network. To establish the inner bound, we introduce a new notion of typicality, the input-driven Markov typicality, and develop its fundamental properties. Contrary to the classical block-Markov coding schemes that rely on blockwise independence for discrete memoryless channels, our analysis directly exploits the Markov channel structure and improves beyond the independence-based arguments.
