2014 Poster Sessions : On Feedback in Gaussian Multi-Hop Networks

Student Name : Farzan Farnia
Advisor : Ayfer Özgur Aydin
Research Areas: Information Systems
The study of feedback has been mostly limited to single-hop communication settings of a few nodes. In this poster, we consider arbitrary Gaussian networks where we assume that some links in the network can be bidirected providing opportunities for feedback. We ask the following question: can the information transfer in both directions of a link be critical to maximizing the end-to-end communication rates in the network? Equivalently, could one of the directions in each bidirected link (and more generally at least one of the links forming a cycle) be shut down and the capacity of the network still be approximately maintained? We show that in any arbitrary Gaussian network with bidrected edges and cycles and unicast, multiple-access or broadcast traffic, we can always identify a directed acyclic subnetwork that approximately maintains the capacity of the original network. On the other hand, with multicast and multiple unicast traffic bidirected information flow across links can be critical to maximizing the end-to-end capacity.

Farzan Farnia is a PhD candidate in the Electrical Engineering department at Stanford University. Prior to joining Stanford, He earned a B.Sc. in Electrical Engineering and a B.Sc. in Mathematics at Sharif University of Technology where he graduated as the top ranking student in his class. His research interests include information theory, wireless networks and bioinformatics. Farzan has been the recipient of the Stanford Graduate Fellowship (Sequoia Capital Fellow) at Stanford University. He was also awarded the Numerical Technologies Founders Prize as the second top performer on the Stanford’s EE PhD Qualifying Exam.