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Abstract
A research area that has recently gained great interest is the development of network architectures relating to the tracking of wireless VoIP devices. This is particularly so for architectures based on the popular Session Initiation Protocol (SIP). Previous work, however, in this area does not consider the impact of combined VoIP and tracking on the capacity and call set-up time of the architectures. Previous work also assumes that location information is always available from sources such as GPS, a scenario that rarely is found in practice. The inclusion of multiple positioning systems in tracking architectures has not been hitherto explored. It is the purpose of this thesis to design and test SIP-based architectures that address these key issues.
Our first main contribution is the development of a tracking-only SIP based architecture. This architecture is designed for intermittent GPS availability, with wireless network tracking as the back-up positioning technology. Such a combined tracking system is more conducive with deployment in real-world environments.
Our second main contribution is the development of SIP based tracking architectures that are specifically aimed at mobile wireless VoIP systems. A key aspect we investigate is the quantification of the capacity constraints imposed on VoIP-tracking
architectures. We identify such capacity limits in terms of SIP call setup time and VoIP QoS metrics, and determine these limits through experimental measurement and theoretical analyses.
Our third main contribution is the development of a novel SIP based location tracking architecture in which the VoIP application is modified. The key aspect of this architecture is the factor of two increase in capacity that it can accommodate relative
to architectures utilizing standard VoIP.
An important aspect of all our tracking architectures is the Tracking Server. This server supplies the location information in the event of GPS unavailability. A final contribution of this thesis is the development of novel particle-filter based tracking algorithms that specifically address the GPS intermittency issue. We show how these filters interact with other features of our SIP based architectures in a seamless fashion.