Storage-Latency Trade-off in Cache-Aided Fog Radio Access Networks

TL;DR

This paper investigates the trade-off between storage capacity and latency in cache-enabled fog radio access networks, proposing a scheme that combines interference management techniques to optimize delivery time.

Contribution

It introduces a novel transmission scheme for F-RANs that combines interference alignment, zero-forcing, and interference cancellation, analyzing the normalized delivery time.

Findings

Achieves improved latency performance through combined interference techniques.

Provides analytical characterization of the normalized delivery time.

Demonstrates benefits of decentralized user caching in F-RANs.

Abstract

A fog radio access network (F-RAN) is studied, in which $K_T$ edge nodes (ENs) connected to a cloud server via orthogonal fronthaul links, serve $K_R$ users through a wireless Gaussian interference channel. Both the ENs and the users have finite-capacity cache memories, which are filled before the user demands are revealed. While a centralized placement phase is used for the ENs, which model static base stations, a decentralized placement is leveraged for the mobile users. An achievable transmission scheme is presented, which employs a combination of interference alignment, zero-forcing and interference cancellation techniques in the delivery phase, and the \textit{normalized delivery time} (NDT), which captures the worst-case latency, is analyzed.