Analysis on Cache-enabled Wireless Heterogeneous Networks

TL;DR

This paper analyzes cache-enabled heterogeneous wireless networks, proposing a content delivery scheme with theoretical performance metrics, and investigates how caching and network heterogeneity affect throughput and delay.

Contribution

It introduces a comprehensive analytical framework for cache-based content delivery in three-tier HetNets, including new models for throughput, delay, and network performance.

Findings

Proposed a content access protocol for cache-enabled HetNets.

Derived theoretical expressions for ergodic rate and outage probability.

Analyzed the impact of network heterogeneity and caching capacity on performance.

Abstract

Caching the popular multimedia content is a promising way to unleash the ultimate potential of wireless networks. In this paper, we contribute to proposing and analyzing the cache-based content delivery in a three-tier heterogeneous network (HetNet), where base stations (BSs), relays and device-to-device (D2D) pairs are included. We advocate to proactively cache the popular contents in the relays and parts of the users with caching ability when the network is off-peak. The cached contents can be reused for frequent access to offload the cellular network traffic. The node locations are first modeled as mutually independent Poisson Point Processes (PPPs) and the corresponding content access protocol is developed. The average ergodic rate and outage probability in the downlink are then analyzed theoretically. We further derive the throughput and the delay based on the \emph{multiclass processor-sharing queue} model and the continuous-time Markov process. According to the critical condition of the steady state in the HetNet, the maximum traffic load and the global throughput gain are investigated. Moreover, impacts of some key network characteristics, e.g., the heterogeneity of multimedia contents, node densities and the limited caching capacities, on the system performance are elaborated to provide a valuable insight.