Cooperative localization in wireless ad-hoc networks based on vector-addition localization scheme with fast message dissemination.
Date of Issue2009
School of Electrical and Electronic Engineering
Positioning and Wireless Technology Centre
Cooperative localization in wireless ad-hoc networks deals with how to utilize local ranging measurements for locating remote nodes. In view of both the pervasive deployment of wireless ad-hoc networks and the incapability of wireless nodes for long-distance ranging, cooperative localization can be found in various applications. This thesis presents the research contributions to a number of theoretical and practical problems about cooperative localization, which can be grouped into two categories. The first contribution consists of using a simple Local Coordinate System for map construction, devising a Vector-addition Localization Scheme for anchor-free cooperative localization, and developing optimal path selection mechanisms for such vector-addition scheme to achieve better accuracy. Two mechanisms for optimal path selection are proposed in this thesis. The first mechanism is based on some geometric heuristics about local coordinate system, which is simple yet universal. Our second mechanism discloses some underlying properties of vector-addition localization scheme, and it makes use of Cramer-Rao Lower Bound (CRLB) as well as geometric principles for optimal path selection. Both mechanisms are able to produce, in term of localization accuracy, better solutions than conventional arbitrary shortest-path approach. The second part of our research work is focused on how to quickly disseminate the local ranging measurement information to the whole wireless ad-hoc network. Such fast message dissemination strategies are generic and thus applicable to many other general operations in wireless ad-hoc networks. Our main contribution in this area is to provide, for collision and collision-free cases, an approximate algorithm that maximizes the number of receptions in each dissemination wave. Our research work does not only produce faster dissemination strategies than previous methods as proved by numerical results, but also sheds light on the underlying theoretical aspects of the generic fast message dissemination problem.
DRNTU::Engineering::Electrical and electronic engineering::Wireless communication systems