SPEAKER: Dr. Ekram Hossain, Department of Electrical and Computer Engineering,
University of Manitoba

TITLE:Interference Modeling in Random Carrier-Sense Multiple Access (CSMA) 
Wireless Networks: A Stochastic Geometry Approach

ABSTRACT
In random networks, point processes are used to statistically describe the 
spatial distribution of the network nodes. A common and analytically tractable 
assumption is that the nodes are distributed in the space according to a 
homogeneous Poisson point process (PPP). Then the aggregate interference is 
obtained using the shot noise theory. However, a PPP cannot be directly used 
to model the spatial distribution of interference sources when modeling 
aggregate interference in random networks using carrier sense multiple access 
with collision avoidance (CSMA/CA). This is because using PPP forbids any two 
points of the process to coexist within a distance less than a certain value. 
This distance reflects the sensing range of the CSMA/CA protocol and defines 
an exclusion region around a receiver. Hard core point process (HCPP), 
introduced by Matern in 1960, is one form of the point processes that has been 
used to model the spatial distribution of interferers in CSMA/CA networks. 
However, HCPP suffers from two major drawbacks. First, it highly underestimates 
the number of the interferers existing in the network, hence, underestimates 
the resultant aggregate interference. Secondly, HCPP is no longer a PPP; hence, 
the well-known formulas available in the literature for the PPP do not apply 
to it. 

In this talk, I will present a modified HCPP model to eliminate the 
underestimation problem and obtain the intensity of the modified HCPP (MHCPP). 
Subsequently, closed-form approximate expressions for the moment generating 
function, mean and variance of the associated aggregate interference will be 
obtained. The accuracy of the MHCPP modeling and the aggregate interference 
approximation will be validated. Extension of the model for the generalized 
fading environments will be also discussed.

SPEAKER BIOGRAPHY: Dr. Ekram Hossain is a Professor in the Department of 
Electrical and Computer Engineering at University of Manitoba, Winnipeg, 
Canada. He received his Ph.D. in Electrical Engineering from University of 
Victoria, Canada, in 2001. Dr. Hossain's main research interest lies in 
resource allocation and multiple-access in wireless/mobile communications 
networks and cognitive radio systems. The books Dynamic Spectrum Access and 
Management in Cognitive Radio Networks (Cambridge University Press, 2009) and 
Cognitive Wireless Communication Networks (Springer, 2007, 
ISBN: 978-0-387-68830-5) are two of his important contributions in these areas. 
Currently he serves as the Area Editor for the IEEE Transactions on Wireless 
Communications in the area of  "Resource Management and Multiple Access", an 
Editor for the IEEE Transactions on Mobile Computing, the IEEE Communications 
Surveys and Tutorials, and IEEE Wireless Communications. He has been appointed 
the Editor-in-Chief for the IEEE Communications Surveys and Tutorials for the 
term 2012-2013. Dr. Hossain has several research awards to his credit, which 
include the University of Manitoba Merit Award in 2010 (for Research and 
Scholarly Activities) and the 2011 IEEE Communications Society Fred Ellersick 
Prize Paper Award. He is a registered Professional Engineer in the province of 
Manitoba, Canada.