Lisa Zhang     
Dr. Lisa Zhang

Distinguished Member of Technical Staff
Bell Labs in Alcatel-Lucent
"Utility Optimization for Multi-Transmitter Wireless Data Systems ”

Tuesday, November 24, 4:00 PM
Packard Lab room 466

Abstract:  We study algorithms for carrier and rate allocation in cellular systems with distributed components such as a heterogeneous LTE system with macrocells and femtocells. Existing work on LTE systems often involves centralized techniques or requires significant signaling, and is therefore not always applicable in the presence of femtocells. More distributed CSMA-based algorithms (carrier-sense multiple access) were developed in the context of 802.11 systems and have been proven to be utility optimal. However, the proof typically assumes a single transmission rate on each carrier. Further, it relies on the CSMA collision detection mechanisms to know whether a transmission is feasible. In this talk we present a framework for LTE scheduling that is based on CSMA techniques. In particular we first prove that CSMA-based algorithms can be generalized to handle multiple transmission rates in a multi-carrier setting while maintaining utility optimality. We then show how such an algorithm can be implemented in a heterogeneous LTE system where the existing Channel Quality Indication (CQI) mechanism is used to decide transmission feasibility.

Bio:  Lisa Zhang is a Distinguished Member of Technical Staff Bell Labs in Murray Hill, New Jersey. Her research broadly concerns algorithmic and complexity issues of networking, with a focus on design and optimization, routing and scheduling protocols, and stability and Quality-of-Service analyses. She holds multiple patents on methods and devices for efficient communications. She has also served on technical and organizing committees of numerous IEEE and ACM conferences. Dr. Zhang received her B.A., summa cum laude, in mathematics from Wellesley College in 1993 and her Ph.D. in Theory of Computing from the Massachusetts Institute of Technology in 1997. She twice won the Bell Labs President's Gold Award and the Lucent Chairman's Award for innovation and technical excellence.

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