The Dean's Seminar Series of College of Engineering, University of Florida 
Co-sponsored by Department of Electrical and Computer Engineering 
and IEEE Gainesville Section 


Cross-Layer Design for Multihop Wireless Networks

Dr. Ness B. Shroff, Professor 
School of Electrical and Computer Engineering
Purdue University

4:00-5:00pm, Wednesday, March 7, 2007
101 New Engineering Building 

Abstract:
      
The layered networking architecture has been instrumental in the
proliferation of communication systems. The success of the layered
architecture has been its ability to provide modularity and
transparency. However, optimizing within layers is insufficient to
obtain the orders -of -magnitude performance gains necessary to fuel
major growth in next-generation wireless services. To achieve these
performance gains, it is imperative that network protocols and
designs are engineered by jointly optimizing across the layers (cross-layer
design). Unfortunately, the Achilles heel of cross-layer design is
its  potential to destroy modularity, hence making the overall system
fragile. In this talk, we develop a "loose -coupling" approach to
address this issue. By loose -coupling, we mean that the cross-layer
solution only requires a minimal amount of interaction between the
layers, and is robust to imperfect decisions made at each layer.
Thus, we gain efficiency while still retaining modularity. We will
focus on the cross-layer congestion control and scheduling problem in
multi-hop wireless networks. We will show that the optimal solution
to this cross-layer problem can be decomposed into a congestion
control component and a scheduling component, with minimal coupling
through queue-length updates. We will also investigate the impact on
the performance of the cross -layer solution if the network can only
use an imperfect (and potentially distributed) scheduling component
that is easier to implement. We will establish desirable performance
bounds for our solution with imperfect scheduling and show how the
insights drawn from our analyses  enable the design of a fully
distributed cross-layer solution.


Biography:

Ness B. Shroff received his Ph.D. degree from Columbia University, NY
in 1994.  He joined Purdue University in November 1994, where he is
currently Professor of Electrical and Computer Engineering and
director of CWSA, a university-wide center for wireless systems and
applications.  He is currently a member of the editorial boards of
IEEE/ACM Trans. on Networking and the Computer Networks Journal.  He
works on fundamental problems aimed at understanding the design,
control, and security of communication networks. 

He is a fellow of the IEEE, and has received numerous awards such as
the NSF CAREER award in 1996, the 2003 best paper of the year award
for Computer Networks,  the 2005 best paper of the year award for the
Journal of Commnications and Networking, the IEEE INFOCOM 2006 best
paper award, and the IEEE IWQoS best student paper award (Also, his
paper on cross-layer design was selected as one of two runner-up
papers at IEEE INFOCOM'05).

In July 2007, he will join The Ohio State University as the Ohio
Eminent Scholar in Networking and Communications, and Professor of
ECE and CSE.

For further information, please contact Dr. Michael Fang at either 
352-846-3043 or fang@ece.ufl.edu