Combinatorial Multi-Access Coded Caching: Improved Rate-Memory Trade-off with Coded Placement

Namboodiri, KKK and Sundar Rajan, B (2023) Combinatorial Multi-Access Coded Caching: Improved Rate-Memory Trade-off with Coded Placement. In: 2023, IEEE Information Theory Workshop, ITW 2023, Saint-Malo, pp. 159-164.

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Abstract

This work considers the combinatorial multi-access coded caching problem introduced in the recent work by Muralidhar et al. [P. N. Muralidhar, D. Katyal, and B. S. Rajan, "MaddahAli-Niesen scheme for multi-access coded caching,"in IEEE Inf. Theory Workshop (ITW), 2021] The problem setting consists of a central server having a library of N files and C caches each of capacity M. Each user in the system can access a unique set of r < C caches, and there exist users corresponding to every distinct set of r caches. Therefore, the number of users in the system is (C r). For the aforementioned combinatorial multi-access setting, we propose a coded caching scheme with an MDS code-based coded placement. This novel placement technique helps to achieve a better rate in the delivery phase compared to the optimal scheme under uncoded placement, when M > N/C. For a lower memory regime, we present another scheme with coded placement, which outperforms the optimal scheme under uncoded placement if the number of files is no more than the number of users. Further, we derive an information-theoretic lower bound on the optimal rate-memory trade-off of the combinatorial multi-access coded caching scheme. Finally, using the derived lower bound, we show that the first scheme is optimal in the higher memory regime, and the second scheme is optimal if N ≤(C r).

Item Type:	Conference Paper
Publication:	2023 IEEE Information Theory Workshop, ITW 2023
Publisher:	Institute of Electrical and Electronics Engineers Inc.
Additional Information:	The copyright for this article belongs to the Institute of Electrical and Electronics Engineers Inc.
Keywords:	C (programming language); Information theory, Caching scheme; Central servers; Information-theoretic lower bounds; Low memory; MDS code; Multiaccess; Optimal rate; Optimal scheme; Trade off; UNCODED, Economic and social effects
Department/Centre:	Division of Electrical Sciences > Electrical Communication Engineering
Date Deposited:	01 Aug 2023 05:08
Last Modified:	01 Aug 2023 05:08
URI:	https://eprints.iisc.ac.in/id/eprint/82751

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