Hotplug Coded Caching: Uncoded versus Row-Wise Coded Placements
Abstract
In the hotplug coded caching model, K users fill their caches of size M as a function of N files, but only an unknown subset of A≤ K users is active in the delivery phase. In all regimes where the optimal hotplug tradeoff is known, it depends only on A, not on K; whether this holds in general is open. We show that: (i) Under uncoded placement, YMA delivery with MAN placement, where offline users are assigned the demands of active users, is optimal. Hence, offline users cause a strict load penalty at intermediate memory sizes, while the MAN placement is optimal for every number of active users; (ii) Under row-wise placement (RWP), where each cache is a function of the user's own row of each file, every classical scheme can be embedded in a Reed-Solomon code. The resulting hotplug scheme has the tradeoff of the classical model with A users, for every A≤ K: there is no load penalty, but the placement depends on K. We then derive a converse for RWP, which shows that: (a) for 2≤ N≤ A, the scheme of Gomez-Vilardebo (GV) is RWP optimal for AM≤ N/(N−1), which settles the RWP tradeoff for N=2; (b) YMA is RWP optimal at AM=N; and (c) for N=A=3, GV is RWP optimal for M≤ 1. Hence, the Reed-Solomon embeddings of these schemes are optimal among embedded RWP schemes.
Related
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BibTeX
@misc{tuninetti2026hotplug,
title = {{Hotplug Coded Caching: Uncoded versus Row-Wise Coded Placements}},
author = {Daniela Tuninetti},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.03045},
eprint = {2611.03045},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.03045},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Hotplug Coded Caching: Uncoded versus Row-Wise Coded Placements
AU - Daniela Tuninetti
PY - 2026
DA - 2026/11/02
PB - arXiv
DO - 10.48550/arxiv.2611.03045
UR - https://arxiv.org/abs/2611.03045
AB - In the hotplug coded caching model, K users fill their caches of size M as a function of N files, but only an unknown subset of A≤ K users is active in the delivery phase. In all regimes where the optimal hotplug tradeoff is known, it depends only on A, not on K; whether this holds in general is open. We show that: (i) Under uncoded placement, YMA delivery with MAN placement, where offline users are assigned the demands of active users, is optimal. Hence, offline users cause a strict load penalty at intermediate memory sizes, while the MAN placement is optimal for every number of active users; (ii) Under row-wise placement (RWP), where each cache is a function of the user's own row of each file, every classical scheme can be embedded in a Reed-Solomon code. The resulting hotplug scheme has the tradeoff of the classical model with A users, for every A≤ K: there is no load penalty, but the placement depends on K. We then derive a converse for RWP, which shows that: (a) for 2≤ N≤ A, the scheme of Gomez-Vilardebo (GV) is RWP optimal for AM≤ N/(N−1), which settles the RWP tradeoff for N=2; (b) YMA is RWP optimal at AM=N; and (c) for N=A=3, GV is RWP optimal for M≤ 1. Hence, the Reed-Solomon embeddings of these schemes are optimal among embedded RWP schemes.
ER -