Degrees of Freedom of Cache-Aided Interference Channels Assisted by Active Intelligent Reflecting Surfaces

TL;DR

This paper explores how active intelligent reflecting surfaces (IRSs) can significantly improve the degrees of freedom in cache-aided wireless networks by joint design of content placement, delivery, and IRS configuration.

Contribution

It introduces a novel one-shot achievability scheme that leverages IRS capabilities, cooperation, and interference alignment to enhance DoF in cache-aided networks.

Findings

IRS deployment increases achievable DoF across various network configurations.

Maximum DoF can be achieved with sufficient IRS elements and cache sizes.

The proposed scheme outperforms traditional methods without IRS assistance.

Abstract

This paper studies cache-aided wireless networks in the presence of active intelligent reflecting surfaces (IRSs) from an information-theoretic perspective. Specifically, we investigate interference management in a cache-aided wireless network assisted by an active IRS to enhance the achievable degrees of freedom (DoF). To this end, we jointly design the content placement, delivery phase, and IRS coefficients, and propose a one-shot achievability scheme. Our scheme exploits transmitters' cooperation, cache contents, interference alignment, and IRS capabilities, based on the network parameters. We derive the achievable one-shot sum-DoF for different cache sizes, network configurations, and numbers of IRS elements, followed by an upper bound. Our results highlight the potential of deploying an IRS in cache-aided wireless communication systems. In particular, they underscore the enhancement of achievable DoF for various parameter regimes, especially when cache sizes are inadequate. Notably, we show that access to an IRS with a sufficient number of elements enables the achievement of the maximum possible DoF for various parameter regimes of interest.