Algorithms for Local Sensor Synchronization

MPhil Thesis Defence


Title: "Algorithms for Local Sensor Synchronization"

By

Mr. Lixing Wang


Abstract

In a wireless sensor network (WSN), each sensor monitors environmental 
parameters, and reports its readings to a base station, possibly through other 
nodes. A sensor works in cycles, in each of which it stays active for a fixed 
duration, and then sleeps until the next cycle. The frequency of such cycles 
determines the portion of time that a sensor is active, and is the dominant 
factor on its battery life. The majority of existing work assumes globally 
synchronized WSN where all sensors have the same frequency. This leads to waste 
of battery power for applications that entail different accuracy of 
measurements, or environments where sensor readings have large variability.

To overcome this problem, we propose LS, a query processing framework for 
locally synchronized WSN. We consider that each sensor ni has a distinct 
sampling frequency fi, which is determined by the application or environment 
requirements. The complication of LS is that ni has to wake up with a network 
frequency Fi>=fi, in order to forward messages of other sensors. Our goal is 
to minimize the sum of Fi without delaying package transmissions. 
Specifically, given a routing tree, we first present a dynamic programming 
algorithm that computes the optimal network frequency of each sensor; then, we 
develop a heuristic for finding the best tree topology, if this is not fixed in 
advance.


Date:			Wednesday, 29 February 2012

Time:			2:00pm – 4:00pm

Venue:			Room 3401
 			Lifts 17/18

Committee Members:	Prof. Dimitris Papadias (Supervisor)
 			Dr. Qiong Luo (Chairperson)
 			Dr. Raymond Wong


**** ALL are Welcome ****