MPhil Thesis Defence


"Distributed Position Estimation for Wireless Sensor Networks"

By

Mr. Victor Cheung


Abstract

In wireless sensor networks (WSNs), estimating nodal positions is
important for routing efficiency and position-based services. Traditional
techniques based on precise measurements of angles and distances are often
expensive and power-inefficient. On the other hand, approaches based on
landmarks often require many powerful landmarks for information
processing. In this thesis, we first discuss the applications and
traditional techniques to estimate positions in wireless environment. Then
a cost-effective and distributed scheme to accurately estimate nodal
positions for WSNs is proposed and inves-tigated. It is based on a machine
learning tool called ISOMAP and can work with coarse measurements without
the need of powerful landmarks. Each node only needs to identify nodes in
its neighborhood and exchange information with them to estimate its
position accurately. In addition, it allows estimation under network
dynamics like nodes joining/leaving the network and presence of nodes with
low power. During the position estimation process, useful information for
position-based routing is already embedded, so no extra transmission is
required for efficient route determination in reporting data to a
collecting node. We have studied and evaluated the scheme's performance
under various system settings through simulation. It is shown to have fast
convergence with low estimation error, even for large networks.


Date:				Monday, 21 August 2006

Time:				10:30a.m.-12:30p.m.

Venue:				Room 5501
				Lifts 25-26

Committee Members:		Dr. Gary Chan (Supervisor)
				Dr. Jogesh Muppala (Chairperson)
				Dr. Shing-Chi Cheung


**** ALL are Welcome ****