A New Method for Employing Feedback to Improve Coding Performance
Abstract
We introduce a novel mechanism, called timid/bold coding, by which feedback can be used to improve coding performance. For a certain class of DMCs, called compound-dispersion channels, we show that timid/bold coding allows for an improved second-order coding rate compared with coding without feedback. For DMCs that are not compound dispersion, we show that feedback does not improve the second-order coding rate. Thus we completely determine the class of DMCs for which feedback improves the second-order coding rate. An upper bound on the second-order coding rate is provided for compound-dispersion DMCs. We also show that feedback does not improve the second-order coding rate for very noisy DMCs. The main results are obtained by relating feedback codes to certain controlled diffusions.
Keywords
Cite
@article{arxiv.1908.11428,
title = {A New Method for Employing Feedback to Improve Coding Performance},
author = {Aaron B. Wagner and Nirmal V. Shende and Yücel Altuğ},
journal= {arXiv preprint arXiv:1908.11428},
year = {2019}
}