Electrical Engineering
      and Computer Sciences

Electrical Engineering and Computer Sciences

COLLEGE OF ENGINEERING

UC Berkeley

Local Estimation of Collision Probabilities in 802.11 WLANs with Hidden Terminals

Michael N Krishnan, Sofie Pollin and Avideh Zakhor

EECS Department
University of California, Berkeley
Technical Report No. UCB/EECS-2009-2
January 5, 2009

http://www.eecs.berkeley.edu/Pubs/TechRpts/2009/EECS-2009-2.pdf

Current 802.11 networks do not typically achieve the maximum potential throughput despite link adaptation and crosslayer optimization techniques designed to alleviate many causes of packet loss. A primary contributing factor is the difficulty in distinguishing between various causes of packet loss, including collisions caused by high network use, co-channel interference from neighboring networks, and errors due to poor channel conditions. In this paper, we propose a novel method for estimating various collision type probabilities locally at a given node of an 802.11 network. Our goal is to design a practical approach, based on combining locally observable quantities with information observed and broadcast by the access point (AP) in order to obtain partial spatial information about the network traffic. We provide a systematic assessment and definition of the different types of collision, and show how to approximate each of them using only local and AP information. Additionally, we show how to approximate the sensitivity of these probabilities to key related configuration parameters including carrier sense threshold and packet length. We verify our methods through NS-2 simulations, and characterize estimation accuracy of each of the considered collision types.


BibTeX citation:

@techreport{Krishnan:EECS-2009-2,
    Author = {Krishnan, Michael N and Pollin, Sofie and Zakhor, Avideh},
    Title = {Local Estimation of Collision Probabilities in 802.11 WLANs with Hidden Terminals},
    Institution = {EECS Department, University of California, Berkeley},
    Year = {2009},
    Month = {Jan},
    URL = {http://www.eecs.berkeley.edu/Pubs/TechRpts/2009/EECS-2009-2.html},
    Number = {UCB/EECS-2009-2},
    Abstract = {Current 802.11 networks do not typically achieve the
maximum potential throughput despite link adaptation and crosslayer optimization techniques designed to alleviate many causes of packet loss. A primary contributing factor is the difficulty in distinguishing between various causes of packet loss, including collisions caused by high network use, co-channel interference from neighboring networks, and errors due to poor channel conditions. In this paper, we propose a novel method for estimating various collision type probabilities locally at a given node of an 802.11 network. Our goal is to design a practical approach, based on combining locally observable quantities with information
observed and broadcast by the access point (AP) in order to
obtain partial spatial information about the network  traffic. We provide a systematic assessment and definition of the different types of collision, and show how to approximate each of them using only local and AP information. Additionally, we show how to approximate the sensitivity of these probabilities to key related configuration parameters including carrier sense threshold and packet length. We verify our methods through NS-2 simulations, and characterize estimation accuracy of each of the considered collision types.}
}

EndNote citation:

%0 Report
%A Krishnan, Michael N
%A Pollin, Sofie
%A Zakhor, Avideh
%T Local Estimation of Collision Probabilities in 802.11 WLANs with Hidden Terminals
%I EECS Department, University of California, Berkeley
%D 2009
%8 January 5
%@ UCB/EECS-2009-2
%U http://www.eecs.berkeley.edu/Pubs/TechRpts/2009/EECS-2009-2.html
%F Krishnan:EECS-2009-2