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