Cache-Aided Multi-Access Multi-User Private Information Retrieval

Abstract

In this paper, we consider the multi-access cache-aided multi-user Private Information Retrieval (MuPIR) problem. In this problem, N files are replicated across S servers. There are K users and C cache nodes, each capable of storing M files. Each user can access L cache nodes, and every cache node can be accessed by several users. Each user wants to retrieve one file from the servers, but users don’t want the servers to know their demands. This problem is an extension of the dedicated cache-aided MuPIR problem, which itself generalizes the single-user PIR setup. In this paper, we propose an order optimal MuPIR scheme that utilizes a multi-access setup of the coded caching problem where every set of L caches is accessed by one user resulting in K=$\begin{pmatrix} c\\ L \end{pmatrix}$. We also propose