Cache-Aided Fog Radio Access Networks with Partial Connectivity

TL;DR

This paper investigates cache-aided fog radio access networks with partial connectivity, proposing a coded caching scheme that minimizes worst-case delivery latency using MDS codes and interference alignment.

Contribution

It introduces a novel caching and transmission scheme for partially-connected F-RANs, optimizing delivery time with new coding and alignment techniques.

Findings

Achieves minimized normalized delivery time for r=2 and arbitrary cache sizes.

Provides bounds for delivery latency with large cache capacities.

Demonstrates effectiveness of MDS codes and interference alignment in this context.

Abstract

Centralized coded caching and delivery is studied for a partially-connected fog radio access network (F-RAN), whereby a set of H edge nodes (ENs) (without caches), connected to a cloud server via orthogonal fronthaul links, serve K users over the wireless edge. The cloud server is assumed to hold a library of N files, each of size F bits; and each user, equipped with a cache of size MF bits, is connected to a distinct set of r ENs; or equivalently, the wireless edge from the ENs to the users is modeled as a partial interference channel. The objective is to minimize the normalized delivery time (NDT), which refers to the worst case delivery latency, when each user requests a single file from the library. An achievable coded caching and transmission scheme is proposed, which utilizes maximum distance separable (MDS) codes in the placement phase, and real interference alignment (IA) in the delivery phase, and its achievable NDT is presented for r = 2 and arbitrary cache size M, and also for arbitrary values of r when the cache capacity is sufficiently large.