Decentralized Coded Caching Without File Splitting

TL;DR

This paper introduces a decentralized coded caching scheme that keeps files intact, simplifying implementation and significantly reducing data delivery rates compared to traditional subfile caching methods.

Contribution

It proposes a novel coded file caching scheme with decentralized placement and efficient delivery algorithms, demonstrating improved performance over uncoded caching.

Findings

Coded file caching reduces delivery rate more than uncoded caching.

The proposed schemes are effective with a small number of subfiles.

Approximate delivery rates are accurately predicted by derived formulas.

Abstract

Coded caching is an effective technique to reduce the redundant traffic in wireless networks. The existing coded caching schemes require the splitting of files into a possibly large number of subfiles, i.e., they perform coded subfile caching. Keeping the files intact during the caching process would actually be appealing, broadly speaking because of its simpler implementation. However, little is known about the effectiveness of this coded file caching in reducing the data delivery rate. In this paper, we propose such a file caching scheme which uses a decentralized algorithm for content placement and either an online clique cover or matching algorithm for the delivery of missing data. We derive approximations for the expected delivery rate of both schemes using the differential equations method, and show them to be tight through concentration analysis and computer simulations. Our numerical results demonstrate that the proposed coded file caching is significantly more effective than uncoded caching in reducing the delivery rate. We furthermore show the additional improvement in the performance of the proposed scheme when its application is extended to subfile caching with a small number of subfiles.