Content Caching and Delivery in Wireless Radio Access Networks

TL;DR

This paper studies caching and delivery strategies in wireless radio access networks with edge caches, introducing new schemes that outperform existing methods by leveraging interference management and wireless fronthaul advantages.

Contribution

It presents two novel delivery schemes for different RAN architectures, combining interference management techniques with cache placement strategies to enhance content delivery efficiency.

Findings

New schemes outperform existing methods across various parameters.

Leveraging wireless fronthaul's broadcast nature improves cooperation among edge nodes.

Caching gains are maximized through opportunistic content placement and delivery.

Abstract

Today's mobile data traffic is dominated by content-oriented traffic. Caching popular contents at the network edge can alleviate network congestion and reduce content delivery latency. This paper provides a comprehensive and unified study of caching and delivery techniques in wireless radio access networks (RANs) with caches at all edge nodes (ENs) and user equipments (UEs). Three cache-aided RAN architectures are considered: RANs without fronthaul, with dedicated fronthaul, and with wireless fronthaul. It first reviews in a tutorial nature how caching facilitates interference management in these networks by enabling interference cancellation (IC), zero-forcing (ZF), and interference alignment (IA). Then, two new delivery schemes are presented. One is for RANs with dedicated fronthaul, which considers centralized cache placement at the ENs but both centralized and decentralized placement at the UEs. This scheme combines IA, ZF, and IC together with soft-transfer fronthauling. The other is for RANs with wireless fronthaul, which considers decentralized cache placement at all nodes. It leverages the broadcast nature of wireless fronthaul to fetch not only uncached but also cached contents to boost transmission cooperation among the ENs. Numerical results show that both schemes outperform existing results for a wide range of system parameters, thanks to the various caching gains obtained opportunistically.