Realizing the Benefits of User-Level Channel Diversity

Speaker: Dr. Roch Guerin, University of Pennsylvania
Abstract: Channel or path diversity is known to improve performance in physical layer designs, channel access strategies, path switching mechanisms, etc. In this talk, we focus on ``user-level'' mechanisms that operate simply by distributing packet transmissions across multiple channels. We seek to understand when, why, and to what extent this can be of benefit, and equally important, whether these benefits can be realized with as little of an added cost as possible. In that context, our main contribution is not so much in identifying optimal policies for leveraging channel diversity, but in introducing the concept of channel ``equivalence'' and demonstrating that channel diversity yields substantial benefits mostly when channels are approximately equivalent. We build on this finding to investigate the robustness of these improvements against errors in the characterization of the available channels or changes in their characteristics. We also explore the sensitivity of the results as the number of available channels varies. Our findings demonstrate that by allowing packet transmissions from multiple users to intelligently share channels, it is possible to improve overall performance and robustness through simple and portable user-level mechanisms. This is joint work with E. Vergetis and S. Sarkar
Biography: Roch Guerin received an engineer degree from ENST, Paris, France, in 1983, and M.S. and Ph.D. degrees in Electrical Engineering from Caltech in 1984 and 1986, respectively. He joined the Electrical and System Engineering department of the University of Pennsylvania in 1998, where he is the Alfred Fitler Moore Professor of Telecommunications Networks. Before joining the University of Pennsylvania, he spent over twelve years at the IBM T. J. Watson Research Center in a variety of technical and management positions. From 2001 to 2004 he was on partial leave from Penn, starting Ipsum Networks, a company that pioneered the concept of route analytics for managing IP networks. Dr. Guerin has published over 100 papers in international journals and conferences, and holds more than 25 patents. He has also been active in standard organizations such as the IETF. His main research interests are in the general area of networking, and how networks are best used by different types of applications, with a particular emphasis on developing "robust" solutions that require minimum involvement on the network's part. Dr. Guerin is a Fellow of the IEEE, and in 1994 he received an IBM Outstanding Innovation Award for his work on traffic management. Dr. Guerin served as editor of the ACM SIGCOMM technical newsletter, CCR, from 1998 to 2001, and returned to CCR as an area editor in 2005. He was an editor for the Journal of Computer Networks, the IEEE Communications Surveys, the IEEE/ACM Transactions on Networking, the IEEE Transactions on Communications, and the IEEE Communications Magazine, and a guest editor of a JSAC issue on Internet QoS published in December 2000. He chaired the IEEE Technical Committee on Computer Communications from 1997 to 1999, and served as member-at-large of the Board-of-Governors of the IEEE Communications Society from 2000 to 2002. He was General Chair of the IEEE INFOCOM'98 conference, Technical Program co-chair of the ACM SIGCOMM'2001 conference, and General Chair of the ACM SIGCOMM’2005 conference. He has been on the Technical Advisory Board of France Telecom since 2001 and was on the Technical Advisory Board of Samsung Electronics in 2003-2004. He has consulted for numerous companies in the networking area. His web page is at http://www.seas.upenn.edu/~guerin and his email address is guerin@ee.upenn.edu.
Presented On: Friday, September 9, 2005
Videotape: Geurin.mov