Fundamental limits of caching: Improved rate-memory tradeoff with coded prefetching

We consider a cache network in which a single server is connected to multiple users via a shared error free link. The server has access to a database with N files of equal length F, and serves K users each with a cache memory of MF bits. A novel centralized coded caching scheme is proposed for scenarios with more users than files N ≤ K and cache capacities satisfying 1/K ≤ M ≤ N/K . The proposed scheme outperforms the best rate-memory region known in the literature if N ≤ K ≤ N2+1/2 .Grant numbers : This work was partially supported by the Catalan Government under grant SGR2017-1479 and the Spanish Government under grant TEC2013-44591-P (INTENSYV).© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works