On Hierarchical Coded Caching with Offline Users
Abstract
This paper studies a two-layer hierarchical network in which some users are offline during the content delivery phase. A two-layer hierarchical network consists of a single server connected to multiple cache-aided mirror sites, and each mirror site is connected to a distinct set of cache-aided users. A scheme for such a hierarchical system with offline users has been proposed recently but considered a special case where all mirror caches have zero memory, which is a significant limitation. We propose an array known as a hierarchical hotplug placement delivery array (HHPDA), which describes the placement and delivery phases of a coded caching scheme for a general two-layer hierarchical network with offline users. Further, we construct a class of HHPDAs using combinatorial t-designs.
Cite
@article{arxiv.2507.00727,
title = {On Hierarchical Coded Caching with Offline Users},
author = {Rashid Ummer N. T. and B. Sundar Rajan},
journal= {arXiv preprint arXiv:2507.00727},
year = {2025}
}
Comments
A short version of this is accepted for presentation in 2025 IEEE Information Theory Workshop; 8 pages, one figure