IEEE Gainesville Section and Department of Electrical and 
Computer Engineering Presents 


Cross-Layer Optimization for Routing Data Traffic 
in UWB-based Sensor Networks 

Thomas Hou, Assistant Professor 
Department of Electrical and Computer Engineering 
Virginia Tech 

2:30-4:00pm, Thursday, August 18, 2005 
201 New Engineering Building 

Abstract 

Ultra-wideband (UWB) has great potential for wireless communications in 
emerging applications such as sensor networks. This talk focuses on 
UWB-based sensor networks and studies the following problem: given a set 
of source sensor nodes in the network each generating a certain data rate, 
is it possible to relay all these rates successfully to the base-station? 
We follow a cross-layer optimization approach, with joint consideration of 
link layer scheduling, power control, and network layer routing. The 
optimization problem is formulated as a non-linear programming problem. 
For small-sized networks, we develop a powerful approximation solution 
procedure to this problem based on the branch-and-bound approach and the 
novel Reformulation-Linearization Technique (RLT). For large-sized networks, 
we propose an efficient heuristic algorithm by partitioning the sensor 
network into a core centered around the base-station and an edge that is 
outside the core. We also provide a closed-form analysis for the maximum 
rate that a base-station can receive. Simulation results exhibit the 
efficacy of our proposed optimization solution procedure and demonstrate 
the importance of the cross-layer approach to UWB-based sensor networks.

Biography
%%%%%%%%%

Dr. Thomas Hou obtained his B.E. degree from the City College of New York 
in 1991, the M.S. degree from Columbia University in 1993, and the Ph.D. 
degree from Polytechnic University, Brooklyn, New York, in 1998, all in 
Electrical Engineering. From 1997 to 2002, Dr. Hou was a principal research 
scientist and project leader at Fujitsu Laboratories of America, IP 
Networking Research Department, Sunnyvale, California. Since Fall 2002, he 
has been an Assistant Professor at Virginia Tech, the Bradley Department of 
Electrical and Computer Engineering, Blacksburg, Virginia.  Dr. Hou's 
research interests are in the algorithmic design and optimization for 
network systems. His current research focuses on wireless ad hoc networks, 
sensor networks, and video over ad hoc networks. He has published over 100 
journal and conference papers in the above areas and is a recipient of 
several best paper awards.  He received ONR Young Investigator Award in 
2003 and NSF CAREER Award in 2004. 


If you have any questions, please contact Dr. Michael Fang at 352-846-3043 
or fang@ece.ufl.edu.