Caching in Combination Networks: Novel Multicast Message Generation and Delivery by Leveraging the Network Topology

TL;DR

This paper introduces a new caching and multicast delivery scheme for combination networks that leverages network topology, significantly reducing download time compared to existing methods.

Contribution

It proposes a novel multicast message generation and delivery method tailored for combination networks, exploiting their symmetric topology for improved efficiency.

Findings

Reduces download time compared to existing schemes

Effective in decentralized and more general relay networks

Outperforms known methods in various network configurations

Abstract

Maddah-Ali and Niesen's original coded caching scheme for shared-link broadcast networks is now known to be optimal to within a factor two, and has been applied to other types of networks. For practical reasons, this paper considers that a server communicates to cache-aided users through $H$ intermediate relays. In particular, it focuses on combination networks where each of the $K = \binom{H}{r}$ users is connected to a distinct $r$-subsets of relays. By leveraging the symmetric topology of the network, this paper proposes a novel method to general multicast messages and to deliver them to the users. By numerical evaluations, the proposed scheme is shown to reduce the download time compared to the schemes available in the literature. The idea is then extended to decentralized combination networks, more general relay networks, and combination networks with cache-aided relays and users. Also in these cases the proposed scheme outperforms known ones.