Coded Caching with Nonuniform Demands

TL;DR

This paper introduces a coded caching scheme for networks with nonuniform file demands, demonstrating that traditional caching of only popular files is suboptimal and proposing a near-optimal alternative.

Contribution

It presents a novel coded caching strategy tailored for nonuniform demands, improving upon traditional methods that cache only the most popular files.

Findings

Coded caching significantly reduces network load with nonuniform demands.

Traditional caching of only popular files is suboptimal in multi-cache settings.

Proposed scheme is proven to be close to optimal.

Abstract

We consider a network consisting of a file server connected through a shared link to a number of users, each equipped with a cache. Knowing the popularity distribution of the files, the goal is to optimally populate the caches such as to minimize the expected load of the shared link. For a single cache, it is well known that storing the most popular files is optimal in this setting. However, we show here that this is no longer the case for multiple caches. Indeed, caching only the most popular files can be highly suboptimal. Instead, a fundamentally different approach is needed, in which the cache contents are used as side information for coded communication over the shared link. We propose such a coded caching scheme and prove that it is close to optimal.