Columbia University Joint CS/EE Networking Seminar Series


Wireless Medium Access: From Local Interactions to Global Efficiency

Javad Ghaderi

University of Illinois at Urbana-Champaign

Apr. 19, 11:00AM, Interschool Lab, 750 CEPSR



Abstract: Emerging wireless networks typically lack any centralized access control entity, and instead vitally rely on the individual nodes to operate autonomously and to efficiently share the medium in a distributed fashion. This requires the nodes to schedule their individual transmissions and decide on the use of a shared medium based on knowledge that is locally available or only involves limited exchange of information. In this talk, I will present a class of random access (CSMA-type) algorithms that use only local queue-length information, yet could provide a striking capability to match the throughput of centralized scheduling algorithms. I will characterize the sharp conditions under which such throughput optimality holds in general network topologies. The random access algorithm is inherently distributed, and when combined with TCP-type congestion control mechanisms, it can provide maximum throughput and Quality-of-Service in multihop wireless networks with dynamic flows. The detailed analysis of the local interactions in wireless networks can also serve as a useful tool in the analysis of other complex networks.

Speaker Biography: Javad Ghaderi is a Ph.D. candidate in the Department of Electrical and Computer Engineering and the Coordinated Science Laboratory at the University of Illinois at Urbana-Champaign (UIUC). He received his M.S. from the University of Waterloo in 2008 and his B.S. from the University of Tehran in 2006, both in Electrical and Computer Engineering. His research interests include network algorithms, network control and optimization, and network information theory. While at UIUC, he has spent summers working in Qualcomm and Alcatel-Lucent Bell Laboratories. Javad is the recipient of the Mac Van Valkenburg Graduate Research Award at UIUC, and is a finalist for the Best Student Paper Award at the 2013 American Control Conference.