Events - Colloquia & Seminars

CCIS Colloquium Spring 2007

Distributed Persistent Data Storage in Wireless Sensor Networks

Speaker: Ben Liang

Affiliation: The University of Toronto

Date: Wednesday, April 18, 2007

Talk: 11:40 a.m., 366 WVH

Abstract

Wireless sensor networks consist of unreliable and energy constrained sensors operating in an unstable communication environment. When these networks are scaled up to thousands or hundreds of thousands of nodes, it is generally inefficient or infeasible to deploy powered sinks or fixed gateways to collect data and forward them to the outside world. In this talk, we discuss how distributed coding techniques can be employed to provide fault-tolerant data storage in a large-scale wireless sensor network where the sensors collectively store the measured data. Attracted by the coding performance and decoding efficiency of fountain codes with a large data set, we propose two decentralized implementations of fountain codes over multiple sensors. Both implementations are based on network-wide random walks. The first implementation, termed Exact Decentralized Fountain Codes, provides the same level of fault tolerance as the original centralized fountain codes. The second implementation, termed Approximate Decentralized Fountain Codes, trades off fault tolerance for lower data dissemination cost. We discuss the design choices and performance analysis of these implementations. We show that, asymptotically and in actual experiments, both implementations are able to provide near-optimal fault tolerance with minimum storage requirement in each sensor.

Brief Biography

Ben Liang received honors simultaneous B.Sc. (valedictorian) and M.Sc. degrees in electrical engineering from Polytechnic University in Brooklyn, New York, in 1997 and the Ph.D. degree in electrical engineering with computer science minor from Cornell University in Ithaca, New York, in 2001. In the 2001 - 2002 academic year, he was a visiting lecturer and post-doctoral research associate at Cornell University. He joined the Department of Electrical and Computer Engineering at the University of Toronto as an Assistant Professor in 2002. His current research interests are in mobile networking and multimedia systems. He received an Intel Foundation Graduate Fellowship in 2000 toward the completion of his Ph.D. dissertation, the Best Paper Award at the IFIP Networking conference in 2005, and the Runner-up Best Paper Award at the International Conference on Quality of Service in Heterogeneous Wired/Wireless Networks in 2006. He has served as Technical Vice Co-chair for IEEE MASS 2006, General Co-chair for Ambi-sys 2008, and a technical program member of several major conferences including IEEE INFOCM, ACM MobiCom, IFIP Networking, IEEE Globecom, IEEE ICC, and IEEE LCN. He is a senior member of IEEE and a member of ACM and Tau Beta Pi.