Decentralized Coded Caching with Distinct Cache Capacities

TL;DR

This paper introduces a new decentralized coded caching scheme for systems with users having different cache sizes, improving delivery efficiency especially when user cache capacities vary significantly.

Contribution

A novel decentralized coded caching scheme tailored for users with distinct cache capacities, outperforming existing methods in scenarios with more users than files.

Findings

Improved delivery rate over shared link compared to state-of-the-art.

Performance gain increases with skewed cache capacities.

Scheme benefits systems with more users than files.

Abstract

Decentralized coded caching is studied for a content server with $N$ files, each of size $F$ bits, serving $K$ active users, each equipped with a cache of distinct capacity. It is assumed that the users' caches are filled in advance during the off-peak traffic period without the knowledge of the number of active users, their identities, or the particular demands. User demands are revealed during the peak traffic period, and are served simultaneously through an error-free shared link. A new decentralized coded caching scheme is proposed for this scenario, and it is shown to improve upon the state-of-the-art in terms of the required delivery rate over the shared link, when there are more users in the system than the number of files. Numerical results indicate that the improvement becomes more significant as the cache capacities of the users become more skewed.