Events Calendar

Opportunistic Routing in Wireless Networks: A Stochastic/Adaptive Control Approach

Speaker: Tara Javidi,
University of California, San DiegoAbstract: Opportunistic routing for multi-hop wireless networks has seen recent research interest to overcome deficiencies of traditional routing. First, we, briefly, cast opportunistic routing as a Markov decision problem (MDP) and introduce a stochastic variant of distributed bellman-ford which provides a unifying framework for various versions of opportunistic routing such as SDF, GeRaF, and EXOR.In the second part of the talk, we touch upon the issue of congestion and throughput optimality by contrasting the opportunistic MDP-based schemes with some back-pressure opportunistic schemes. We propose a modification of the MDP framework to arrive at a throughput-optimal policy, aka ORCD, that exhibits significant delay improvements over existing candidates in the literature. In the process of proving throughput optimality for ORCD, we introduce a new Lyapunov function construction which characterizes an important and large class of throughput optimal policies. The proposed class includes backpressure and ORCD as simple special cases.To formulate and identify the optimal routing strategy, MDP formulations rely on the availability of probabilistic (Markov) models. Lastly (and time-permitting), we build on our earlier work on sensitivity analysis for opportunistic schemes and use a reinforcement learning framework to propose an adaptive opportunistic routing algorithm. The proposed scheme minimizes the expected average cost per packet independently of the initial knowledge about the channel quality and statistics across the network.Biography: Tara Javidi studied electrical engineering at Sharif University of Technology, Tehran, Iran from 1992 to 1996. She received the MS degrees in electrical engineering (systems), and in applied mathematics (stochastics) from the University of Michigan, Ann Arbor, in 1998 and 1999, respectively. She received her Ph.D. in electrical engineering and computer science from the University of Michigan, Ann Arbor, in 2002.From 2002 to 2004, she was an assistant professor at the Electrical Engineering Department, University of Washington, Seattle. She joined University of California, San Diego, in 2005, where she is currently an assistant professor of electrical and computer engineering. She was a Barbour Scholar during 1999-2000 academic year and received an NSF CAREER Award in 2004. Her research interests are in communication networks, stochastic resource allocation, stochastic control theory, and wireless communications.Hosts: Rahul Jain, rahul.jain@usc.edu, EEB 328, x02246
Michael Neely, neely@usc.edu, EEB 520, x03505

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

Audiences: Everyone Is Invited

Contact: Gerrielyn Ramos