Toronto Networking Seminar


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







Connectivity Properties of 
Cooperative Wireless Ad Hoc Networks





Don Towsley


Department of Computer 
Science


University of Massachusetts




Date:  Tuesday, September 1,  10:30am

Location: BA 5256 



Abstract:




  Extensive research has demonstrated the potential improvement in physical 
  layer performance when multiple radios transmit concurrently in the same radio 
  channel. We consider here how such cooperation affects the required node 
  density for full connectivity and percolation for different values of the path 
  loss exponent, $\alpha$ in large wireless ad hoc networks. For one-dimensional 
  (1-D) extended networks, in contrast to non-cooperative networks, full 
  connectivity occurs for any node density when $\alpha$ <= one. Conversely, 
  there exist unconnected nodes with probability one when $\alpha$ > 1, and the 
  network does not percolate for any node density if $\alpha$ > 2. The existence 
  of percolation remains an open problem for 1 < $\alpha$ <= 2 in the 
  one-dimensional (1-D) case. In two-dimensional (2-D) extended networks with 
  non-coherent cooperation, full connectivity is achieved for any node density 
  with $\alpha$ <= 2. Conversely, there exist disconnected nodes with 
  probability one when $\alpha$ > 2; however the cooperative network percolates 
  for node densities above a threshold which is strictly less than that of the 
  non-cooperative network.

  

  The above results hold in the presence of receiver cooperation. We also 
  present results for the case that senders cooperate but receivers do not.

  

  Joint work with D. Goeckel, B. Liu, L. Wang, C. Westphal 



Bio:


Don Towsley received a B.A. 
  degree in physics and a Ph.D. degree in computer science, both from University 
  of Texas University. He is currently a Distinguished University Professor in 
  the Department of Computer Science at the University of Massachusetts - 
  Amherst, where he co-directs the Networking Research Laboratory. Professor 
  Towsley has been a Visiting Scientist at AT&T Labs - Research, IBM Research, 
  INRIA , Microsoft Research Cambridge, and the University of Paris 6.

  

  Dr. Towsley's research interests include network measurement, modeling, and 
  analysis. He served as Editor-in-Chief of the IEEE/ACM Transactions on 
  Networking and is on the editorial boards of Journal of the ACM and IEEE 
  Journal of Selected Areas in Communications. He is also currently Chair of the 
  IFIP Working Group 7.3 on computer performance measurement, modeling, and 
  analysis. He has also served on numerous editorial boards including those of 
  IEEE Transactions on Communications and Performance Evaluation. He has been 
  active in the program committees for numerous conferences including IEEE 
  Infocom, ACM SIGCOMM, ACM SIGMETRICS, and IFIP Performance conferences for 
  many years, and has served as Technical Program Co-Chair for ACM SIGMETRICS 
  and Performance conferences.

  

  Dr. Towsley has received the 2007 IEEE Koji Kobayashi Computer and 
  Communications Award , the 2007 ACM SIGMETRICS Achievement Award, the 1999 
  IEEE Communications Society William Bennett Award, and several conference and 
  workshop best paper awards. He is also the recipient of the University of 
  Massachusetts Chancellor's Medal and the Outstanding Research Award from the 
  College of Natural Science and Mathematics at the University of Massachusetts. 
  He is one of the founders of the Computer Performance Foundation. He has twice 
  received IBM Faculty Fellowship Awards, and is a Fellow of the IEEE and the 
  ACM.



Host of the talk



  Peter Marbach (marbach@cs.toronto.edu)