April 29, 2008 - Dina Papagiannaki

Title: Self-Organization in High Density 802.11 Wireless Access Networks

Abstract:
The increased popularity of IEEE 802.11 WLANs has led to dense deployments in urban areas. Such high density leads to sub-optimal performance unless the interfering networks learn how to optimally share the spectrum. In this talk I will describe three distributed algorithms that allow (i) multiple interfering 802.11 WLANs to select their operating frequency in a way that minimizes global interference, (ii) clients to choose their Access Point so that the bandwidth of all interfering networks is shared optimally, (iii) APs and clients to select their transmission power and Clear Channel Assessment (CCA) threshold so as to maximize the overall network capacity. All algorithms fall into a unified framework based on Gibbs sampling and optimize global network performance based on local information. They do not require explicit coordination among the wireless devices, and can thus operate in diverse cooperative environments with no single administrative authority. We study implementation requirements and show that significant benefits can be gained using a prototype implementation on the Intel 2915 ABG wireless network interface cards.