# Throughput-Outage Analysis and Evaluation of Cache-Aided D2D Networks with Measured Popularity Distributions

## TL;DR

This paper investigates the real-world performance of cache-aided D2D networks using measured video popularity data modeled by MZipf distribution, confirming theoretical benefits in practical scenarios through analysis and numerical experiments.

## Contribution

It introduces a realistic popularity distribution model for mobile video requests and analyzes the throughput-outage tradeoff, validating theoretical scaling laws with real-world data.

## Key findings

- MZipf distribution fits practical data well
- Theoretical scaling laws hold for skewed MZipf distributions
- Cache-aided D2D outperforms traditional unicasting

## Abstract

Caching of video files on user devices, combined with file exchange through device-to-device (D2D) communications is a promising method for increasing the throughput of wireless networks. Previous theoretical investigations showed that throughput can be increased by orders of magnitude, but assumed a Zipf distribution for modeling the popularity distribution, which was based on observations in {\em wired} networks. Thus the question whether cache-aided D2D video distribution can provide in practice the benefits promised by existing theoretical literature remains open. To answer this question, we provide new results specifically for popularity distributions of video requests of mobile users. Based on an extensive real-world dataset, we adopt a generalized distribution, known as Mandelbrot-Zipf (MZipf) distribution. We first show that this popularity distribution can fit the practical data well. Using this distribution, we analyze the throughput--outage tradeoff of the cache-aided D2D network and show that the scaling law is identical to the case of Zipf popularity distribution when the MZipf distribution is sufficiently skewed, implying that the benefits previously promised in the literature could indeed be realized in practice. To support the theory, practical evaluations using numerical experiments are provided, and show that the cache-aided D2D can outperform the conventional unicasting from base stations.