Codes and Capacity for Bidirectional Communication on Lines, Stars, and Rings

SPEAKER: Dr. Gerhard Kramer, Member of Technical Staff, Communications and Statistical Sciences Dept., Bell Labs, Alcatel-LucentABSTRACT: This talk describes codes and capacity bounds for two-way communication in three classes of networks that are elements of larger networks. We begin by considering bidirectional line networks with both edge and node capacity constraints, as well as multiple multi-cast traffic sessions. For wired line networks, we construct an explicit binary network code that achieves capacity. The converse theorem requires using our progressive d-separating edge set (PdE) bound, which is a fundamental generalization of a standard cut bound. Second, we extend the results to line networks with broadcasting nodes by studying a two-way relay channel with three nodes: two sources and a relay. We develop several coded modulation techniques that achieve all rate points inside the capacity region. Third, we extend coding for the three-node topology to many nodes and develop a separation-based coding method that achieves good rates. We show that this approach achieves capacity if the broadcast channels are physically degraded and the multi-access channels exhibit uniform-phase fading. Finally, we outline extensions of the ideas to star and ring networks.BIO: Gerhard Kramer received the B.Sc. and M.Sc. degrees in electrical engineering from the University of Manitoba in Canada and the Dr. sc. techn. (Doktor der Technischen Wissenschaften) degree from the Swiss Federal Institute of Technology (ETH) in Zurich, Switzerland. From July 1998 to March 2000, he was with Endora Tech AG, Basel, Switzerland, as a communications engineering consultant. Since May 2000 he has been with Bell Laboratories, Murray Hill, NJ, USA. His research has been focused on information theory, communications theory, iterative decoding, and source coding.Dr. Kramer is currently serving as an Associate Editor for Shannon Theory for the IEEE Transactions on Information Theory. He served as Guest Editor-in-Chief for an IEEE Transactions on Information Theory Special Issue on Relaying and Cooperation in Communication Networks in 2006-2007, and as Publications Editor for the same Transactions during 2004-2005. He is serving as Co-Chair of the Technical Program Committee for the 2008 IEEE International Symposium on Information Theory. Dr. Kramer is a co-recipient of the IEEE Communications Society 2005 Stephen O. Rice Prize paper award, a Bell Labs President's Gold Award in 2003, and a recipient of an ETH Medal in 1998.HOST: Dr. Alan Willner, willner@usc.edu

Location: Hughes Aircraft Electrical Engineering Center (EEB) - 248

Audiences: Everyone Is Invited

Contact: Mayumi Thrasher