Efficient wireless content delivery network design and control

Abstract

Demand for mobile data traffic by a rapid proliferation of mobile devices has explosively increased. According to the Cisco VNI report, mobile video will increase 13-fold between 2015 and 2020, taking a share of 72% of the total mobile data traffic in 2020. This growth of mobile video services has introduced a significant challenge for efficient delivery of video content in wireless networks while satisfying user quality of service (QoS) expectations. Content delivery networks (CDNs) have rapidly grown in popularity as a primary alternative to improve content accessibility and QoS as well as to alleviate network congestion. A number of previous research efforts have focused on addressing design and control strategies for efficient CDN systems. They have been mainly studied in the context of wired networks. Unfortunately, the issues in wireless networks have gone relatively unexplored. This strongly motivated us to tackle an intriguing problem of how to design and control an efficient CDN system to achieve optimal performance in wireless environment. As a clue to the fundamental solution of the problem, we note the deep caching concept that is a advanced CDN variant in which content caches are installed within networks (not at borders or edges) closer to users. As feasible approaches to realize deep caching, we consider two candidates widely known as low-cost networking solutions: small-cell mesh networking and device-to-device (D2D) communication networking. In the first part of this thesis, we address cache placement design issues in a wireless CDN with small-cell mesh networking and propose efficient design strategies for the system. In the second part, we consider a network-assisted D2D CDN where a cellular network assists and controls D2D communication processes and propose efficient content placement design and request routing control algorithms.