Cyclic Wrap-Around Multi-Access Coded Caching with Private Caches

TL;DR

This paper introduces a new cyclic wrap-around multi-access coded caching model with private caches, deriving bounds and schemes that optimize data transmission rates and generalize existing caching strategies.

Contribution

It develops a lower bound and an achievable scheme for the new caching model, extending the Maddah-Ali-Niesen scheme to cyclic multi-access scenarios.

Findings

The proposed scheme is optimal in large memory regimes.

The lower bound applies to both coded and uncoded cache placements.

Numerical results show the scheme's rate matches the lower bound in key regimes.

Abstract

We consider a variant of the coded caching problem where users connect to two types of caches, called private caches and access caches. The problem setting consists of a server having a library of files and a set of access caches. Every user, equipped with a private cache, connects to $L$ neighboring access caches in a cyclic wrap-around fashion. The server populates the private and access caches with file contents in either coded or uncoded format. For this setting, we derive a lower bound on the optimal worst-case transmission rate using cut-set arguments. This lower bound applies to both coded and uncoded placements. We then provide an achievable scheme with uncoded placement and show that our scheme specializes to the well-known Maddah-Ali-Niesen scheme for the dedicated cache network in the absence of access caches. Finally, we show that the proposed scheme achieves optimality in large memory regimes and provide numerical plots comparing the rate of the proposed scheme with the derived lower bound, demonstrating the optimality of our scheme.