Placement Delivery Arrays for Coded Caching with Shared and Private Caches

Namboodiri, KKK and Peter, E and Rajan, BS (2024) Placement Delivery Arrays for Coded Caching with Shared and Private Caches. In: International Symposium on Information Theory, ISIT 2024, 7 July 2024 - 12 July 2024, Athens, pp. 1664-1669.

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Abstract

We consider a coded caching network consisting of a server with a library of N files connected to K users, where each user is equipped with a dedicated cache of size Mp units. In addition to that, the network consists of �� K helper caches, each with a size Mh units. Each helper cache can serve an arbitrary number of users; however, each user can access only a single helper cache. Also, we assume that the server knows the user-to-helper cache association, defined as the sets of users connected to each helper cache, during the cache placement phase. We propose a solution for the aforementioned coded caching problem by introducing a combinatorial structure called a Shared and Private Placement Delivery Array (SP-PDA). These SP-PDAs describe the helper cache placement, private cache placement, and the server transmissions in a single array. Further, we propose a novel construction of SP-PDAs using two Placement Delivery Arrays (PDAs). Interestingly, we observe that the permutations of the columns of the two chosen PDAs result in SP-PDAs with different performances. Moreover, we characterize the conditions for selecting the best column permutations of the chosen PDAs. Furthermore, the coded caching schemes resulting from SP-PDAs subsume two existing coded caching schemes as special cases. Additionally, SP-PDAs enable the construction of coded caching schemes with much smaller subpacketization numbers-subpacketization number is defined as the number of subfiles to which a file is divided-compared to the existing schemes, without paying much in terms of rate (the size of the transmission in the delivery phase). © 2024 IEEE.

Item Type:	Conference Paper
Publication:	IEEE International Symposium on Information Theory - Proceedings
Publisher:	Institute of Electrical and Electronics Engineers Inc.
Additional Information:	The copyright for this article belongs to the publishers.
Keywords:	Proxy caches, Arbitrary number; Cache placement; Caching scheme; Column permutations; Combinatorial structures; Condition; Novel construction; Performance; Private placements, Cache memory
Department/Centre:	Division of Electrical Sciences > Electrical Communication Engineering
Date Deposited:	23 Sep 2024 10:23
Last Modified:	23 Sep 2024 10:23
URI:	http://eprints.iisc.ac.in/id/eprint/86303

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