Toronto Networking Seminar

Organized by Department of Computer Science and Department of Electrical and Computer Engineering, University of Toronto

Delay Performance of CSMA policies in Multihop Wireless Networks: A New Perspective

Mahdi Lotfinezhad
Department of Computer Science
University of Toronto


Thursday, May 11, 3pm
BAB025 (Bahen Centre Basement)


This talk focuses on the delay performance of CSMA policies in wireless networks, where the delay is defined as the average time that a silent wireless link needs to wait until it accesses the channel for packet transmission. It is well-known that CSMA policies can incur an access delay that may be correlated over time and may grow exponentially with the network size. This discourages practical implementation of CSMA policies in even mid-sized networks. This talk provides a new perspective on the delay performance of CSMA policies. It presents recently developed results for two important interference models and show how CSMA policies can be used to ensure an access delay that is memoryless over time or that does not grow with the network size. The two interference models that we consider are primary interference and the ``lattice interference graph''. The results presented suggest that CSMA policies can achieve a delay performance, as well as a delay-throughput trade-off, that makes them viable to be used in practice. These results find further applications in the analysis of percolative systems.


Mahdi Lotfinezhad received the B.Sc. degree in electrical engineering from the Sharif University of Technology in 2003, and the M.A.Sc. and Ph.D. degrees from the University of Toronto in 2004 and 2009, both in electrical and computer engineering. He is currently a post doctoral fellow in the department of Computer Science at University of Toronto. His doctoral research has focused on the complexity and stability properties of scheduling policies in wireless networks with time-varying channels and populations. His current focus is on the convergence and delay properties of CSMA random access policies.

Host of Talk:

Peter Marbach (