Coded Caching Clusters with Device-to-Device Communications

TL;DR

This paper analyzes energy-efficient coded caching in D2D networks, demonstrating that erasure coding significantly reduces energy costs and offers economic benefits for operators in geographically constrained mobile communities.

Contribution

It provides closed-form expressions for energy costs and shows that erasure coding combined with D2D caching drastically reduces energy consumption and costs.

Findings

Energy consumption reduced by over 90% with coding.

Coded D2D caching offers notable savings for operators.

Closed-form formulas for energy costs are derived.

Abstract

We consider a geographically constrained caching community where popular data files are cached on mobile terminals and distributed through Device-to-Device (D2D) communications. Further, to ensure availability, data files are protected against user mobility, or churn, with erasure coding. Communication and storage costs (in units of energy) are considered. We focus on finding the coding method that minimizes the overall cost in the network. Closed-form expressions for the expected energy consumption incurred by data delivery and redundancy maintenance are derived, and it is shown that coding significantly decreases the overall energy consumption -- by more than 90% in a realistic scenario. It is further shown that D2D caching can also yield notable economical savings for telecommunication operators. Our results are illustrated by numerical examples and verified by extensive computer simulations.