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.

About Lisa Zhang

I was born and brought up in Shanghai, China. I spent eight years of my childhood in Jing’an District Primary School and Kindergarten, and six years of my adolescence in Yucai High School. I arrived in America in the summer of 1989 and spent the next eight years in the Boston area, first studying at Wellesley College then at MIT. In 1997, after my Ph.D, I landed a research position at Bell Labs in Murray Hill, NJ, and it remains the only job I have had. At the time Bell Labs was the research arm of Lucent Technologies. It was spun off from AT&T in 1996 and merged with Alcatel in 2006.

My research broadly concerns algorithmic and complexity issues of networking, which includes network planning and optimization, routing and scheduling protocols, and stability and Quality-of-Service analysis. My work is interdisciplinary, covering topics in theoretical computer science, applied mathematics, operations research and electrical engineering.

Right now I’m serving on the organizing committees of IEEE FOCS 2014 and the 4th Women in Theory Workshop 2014, and the technical program committee of ACM STOC 2014. In the past, I served on the committees of IEEE Infocom 2012, IEEE FOCS 2011, ISAAC 2011, IEEE Infocom 2011, IEEE IPDPS 2010, IEEE Infocom 2010, ACM STOC 2009, ACM-SIAM SODA 2009, ACM SPAA 2009, IEEE Infocom 2009, IEEE Infocom 2008, APPROX 2007, DCOSS 2007, IEEE Infocom 2007 ACM STOC 2001. Recently I taught an Analysis of Algorithms course at Columbia University, which I really enjoyed.

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This event will be conducted in English