Relaying in Networks

Back to Seminar Archive...

Friday, November 4, Storer Hall 1322, 12:10pm-1:00pm

Speaker: Abbas El Gamal
Stanford University

Host: Professor Bernard Levy


Ford and Fulkerson (1956) showed that the capacity of graphical unicast networks is achieved by routing at the relay nodes. Ahlswede, Cai, Li, Yeung (2000) showed that routing alone does not achieve the capacity in the multicast case and more sophisticated "network coding" is needed at the relays. This seminal result has since been extended to deterministic networks by Ratnakar and Kramer (2006) and Avestimehr, Diggavi, and Tse (2007), and to erasure networks by Dana, Gowaikar, Palanki, Hassibi, and Effros (2006). In a separate and seemingly unrelated line of investigation, Cover and El Gamal (1979) developed the decode--forward and compress--forward schemes for the relay channel, which is the simplest example of a wireless multihop network. Recently, we showed that a generalization of compress--forward naturally extends network coding and its subsequent extensions to networks with interference, broadcasting and noise. I will present the ideas behind these results without as suming background in network information theory.

This talk is based on material from the upcoming Network Information Theory book with Young-Han Kim.



Abbas El Gamal is the Hitachi America Professor in the School of Engineering at Stanford University. His research contributions have spanned several areas, including network information theory, Field Programmable Gate Array, and digital imaging devices and systems. He has authored or coauthored over 200 papers and holds 30 patents in these areas. El Gamal is a Fellow of the IEEE and has received several honors and awards for his research contributions, including the 2012 Claude E. Shannon Award and the 2004 INFOCOM Paper Award.