Multi-Access Coded Caching Schemes From Cross Resolvable Designs

Abstract

We present a novel caching and coded delivery scheme for a multi-access network where multiple users can have access to the same cache (shared cache) and multiple caches can be accessed by the same user. This scheme is obtained from resolvable designs satisfying certain conditions which we call cross resolvable designs. To be able to compare different multi-access coded schemes with different number of users we normalize the rate of the schemes by the number of users served. Based on this per-user-rate we show that our scheme performs better than the well known Maddah-Ali -Niesen (MaN) scheme and the recently proposed ("Multi-access coded caching: gains beyond cache-redundancy" by Serbetci, Parrinello and Elia) SPE scheme. It is shown that the resolvable designs from affine planes are cross resolvable designs and our scheme based on these performs better than the MaN scheme for large memory size cases. The exact size beyond which our performance is better is also presented. The SPE scheme considers only the cases where the product of the number of users and the normalized cache size is 2, whereas the proposed scheme allows different choices depending on the choice of the cross resolvable design.

Maddah-Ali-Niesen Scheme for Multi-access Coded Caching

“…In [7], the authors develop a multi-access scheme from a specific type of resolvable designs called Cross Resolvable Designs (CRD) and the setup of the multi-access network discussed here depends on the cross resolvable design chosen. The effective file fraction accessible to the user by this setup is less than zM N as opposed to the other schemes discussed previously.…”

“…The number of users supported here, is significantly higher than the other existing schemes for the same number of caches and for practically realizable subpacketization levels. Our work considers only the setup in [7]. To perform comparison of coded caching schemes for various multi-access topologies, we use the metric per user rate or rate per user defined in [7].…”

“…Our work considers only the setup in [7]. To perform comparison of coded caching schemes for various multi-access topologies, we use the metric per user rate or rate per user defined in [7].…”

“…In such cases caching schemes suited for such situations have to be implemented. In the recent years, coded caching schemes for various cache share situations have been studied in the work of [2], [3], [4], [5], [6], [7], [8], [9] etc. In this work, we propose a new construction of a combinatorial structure called cross resolvable designs which was first discussed in [7] and develop multi-access coded caching from it.…”

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Multi-access coded caching schemes from cross resolvable designs (CRD) have been reported recently [7]. To be able to compare coded caching schemes with different number of users and possibly with different number of caches a new metric called rate-per-user was introduced and it was shown that under this new metric the schemes from CRDs perform better than the Maddah-Ali-Niesen scheme in the large memory regime.

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