Capacity of Large-scale CSMA Wireless Networks

In the literature, asymptotic studies of multi-hop wireless network capacity often consider only centralized and deterministic TDMA (time-division multi-access) coordination schemes. There have been fewer studies of the asymptotic capacity of large-scale wireless networks based on CSMA (carrier-sensing multi-access), which schedules transmissions in a distributed and random manner. With the rapid and widespread adoption of CSMA technology, a critical question is that whether CSMA networks can be as scalable as TDMA networks. To answer this question and explore the capacity of CSMA networks, we first formulate the models of CSMA protocols to take into account the unique CSMA characteristics, not captured by existing interference models in the literature. These CSMA models determine the feasible states, and consequently the capacity of CSMA networks. We then study the throughput efficiency of CSMA scheduling as compared to TDMA. Finally, we tune the CSMA parameters so as to maximize the throughput to the optimal order. As a result, we show that CSMA can achieve throughput as Ω(1/√n), the same order as optimal centralized TDMA, on uniform random networks. Our CSMA scheme makes use of an efficient backbone-peripheral routing scheme and a careful design of dual carrier-sensing and dual channel scheme. We also address practical implementation issues of our capacity-optimal CSMA scheme.

This is a joint work with Dr. Chi-Kin Chau from University College London, and Soung Chang Liew from The Chinese University of Hong Kong.

Speaker Details

Minghua Chen received his B.Eng. and M.S. degrees from the Department of Electronics Engineering at Tsinghua University in 1999 and 2001, respectively. He received his Ph.D. degree from the Department of Electrical Engineering and Computer Sciences at University of California at Berkeley in 2006. He spent one year visiting Microsoft Research Redmond as a Postdoc Researcher. He joined the Department of Information Engineering, the Chinese University of Hong Kong, in 2007, where he currently is an Assistant Professor. He received the Eli Jury award from UC Berkeley in 2007 (presented to a graduate student or recent alumnus for outstanding achievement in the area of Systems, Communications, Control, or Signal Processing), the ICME Best Paper Award in 2009, and the IEEE Transactions on Multimedia Best Paper Award in 2009. His research interests include complex systems (currently focusing on smart
grid) and networked systems, distributed and stochastic network optimization and control, multimedia networking, Peer-to-Peer networking, wireless networking, multi-level trust data privacy, secure network coding and network coding for security.

Date:
Speakers:
Minghua Chen
Affiliation:
Chinese University of Hong Kong
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      Minghua Chen

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