Coded caching with helper nodes: an index coding bound and optimality results

Parrinello, Emmanuele; Ünsal, Ayse; Elia, Petros
Technical Report RR-18-336, April 2018 ; Also Submitted to ArXiV, 25 September 2018

The work identifies the fundamental limits of coded caching when the K receiving users share {Lambda} K helper-caches, each assisting an arbitrary number of different users. The main result is the derivation of the exact optimal worst-case delivery time - under the assumption of uncoded cache placement - for any user-to-cache association profile, where each such profile describes how many users are helped by each cache. This is achieved with a new information-theoretic converse that is based on index coding and which proves that a simple XOR-shrinking-and-removal coded-caching scheme is optimal irrespective of the user-to-cache association profile. All the results also apply directly to the coded caching problem with multiple file requests.
 

Type:
Rapport
Date:
2018-04-17
Department:
Systèmes de Communication
Eurecom Ref:
5533
Copyright:
© EURECOM. Personal use of this material is permitted. The definitive version of this paper was published in Technical Report RR-18-336, April 2018 ; Also Submitted to ArXiV, 25 September 2018 and is available at :

PERMALINK : https://www.eurecom.fr/publication/5533