PhD Dissertation, University of Helsinki, 2015


Collaborative Traffic Offloading for Mobile Systems

Abstract:

Due to the popularity of smartphones and mobile streaming 
services, the growth of traffic volume in mobile networks 
is phenomenal. This leads to huge investment pressure on 
mobile operators' wireless access and core infrastructure, 
while the profits do not necessarily grow at the same pace. 
As a result, it is urgent to find a cost-effective solution 
that can scale to the ever increasing traffic volume 
generated by mobile systems. Among many visions, mobile 
traffic offloading is regarded as a promising mechanism by 
using complementary wireless communication technologies, 
such as WiFi, to offload data traffic away from the 
overloaded mobile networks. The current trend to equip 
mobile devices with an additional WiFi interface also 
supports this vision. 

This dissertation presents a novel collaborative architecture 
for mobile traffic offloading that can efficiently utilize 
the context and resources from networks and end systems. 
The main contributions include a network-assisted offloading 
framework, a collaborative system design for energy-aware 
offloading, and a software-defined networking (SDN) based 
offloading platform. Our work is the first in this domain 
to integrate energy and context awareness into mobile traffic 
offloading from an architectural perspective. We have 
conducted extensive measurements on mobile systems to 
identify hidden issues of traffic offloading in the 
operational networks. We implement the offloading protocol 
in the Linux kernel and develop our energy-aware offloading 
framework in C++ and Java on commodity machines and 
smartphones. Our prototype systems for mobile traffic 
offloading have been tested in a live environment. The 
experimental results suggest that our collaborative 
architecture is feasible and provides reasonable improvement 
in terms of energy saving and offloading efficiency. We 
further adopt the programmable paradigm of SDN to enhance 
the extensibility and deployability of our proposals. We 
release the SDN-based platform under open-source licenses 
to encourage future collaboration with research community 
and standards developing organizations. As one of the 
pioneering work, our research stresses the importance of 
collaboration in mobile traffic offloading. The lessons 
learned from our protocol design, system development, and 
network experiments shed light on future research and 
development in this domain.


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@phdthesis{Ding:Thesis:PhD:2015,
author       = {Yi Ding}, 
title        = {Collaborative Traffic Offloading for Mobile Systems},
school       = {University of Helsinki},
year         = 2015,
month        = 11,
}

Yi Ding. Collaborative Traffic Offloading for Mobile Systems. Doctoral Dissertation, University of Helsinki, 2015.