The Effects of Mobility on the Hit Performance of Cached D2D Networks

TL;DR

This paper investigates how user mobility impacts the performance of cached device-to-device networks, introducing a new metric and analyzing the effects of different file-size distributions through explicit expressions and simulations.

Contribution

It introduces the Service Success Probability metric and derives explicit expressions for D2D networks considering mobility and file-size distributions.

Findings

Mobility influences the Service Success Probability significantly.

Different file-size distributions affect network performance distinctly.

Simulations validate analytical expressions and provide system design insights.

Abstract

A device-to-device (D2D) wireless network is considered, where user devices also have the ability to cache content. In such networks, users are mobile and communication links can be spontaneously activated and dropped depending on the users' relative position. Receivers request files from transmitters, these files having a certain popularity and file-size distribution. In this work a new performance metric is introduced, namely the Service Success Probability, which captures the specificities of D2D networks. For the Poisson Point Process case for node distribution and the SNR coverage model, explicit expressions are derived. Simulations support the analytical results and explain the influence of mobility and file-size distribution on the system performance, while providing intuition on how to appropriately cache content on mobile storage space. Of particular interest is the investigation on how different file-size distributions (Exponential, Uniform, or Heavy-Tailed) influence the performance.