Seminar Series
Topics in Systems

A Theory of QoS for Wireless

I-Hong Hou
UIUC

Abstract
Wireless networks are increasingly used to carry applications with QoS
constraints. Two problems arise when dealing with traffic with QoS
constraints. One is admission control, that is, how to verify whether it is
possible to fulfill the demands of a set of clients. The other is finding an
optimal scheduling policy to meet the demands of all clients. We propose a
framework for jointly addressing three QoS criteria: channel reliability,
end-to-end delay, and delivery ratio. We analytically prove a necessary and
sufficient condition for a set of clients to be feasible with respect to the
above three criteria. We further propose two scheduling policies and prove
they are optimal in the sense that they can meet the demands of every
feasible set of clients. In addition, we show that these policies are easily
implementable on existing IEEE 802.11 mechanisms. We also determine a linear
time algorithm to decide whether a set of clients is feasible. Simulation
results confirm the theoretical studies and suggest that the proposed
policies outperform others tested under a variety of settings.

3:30 - 4:30 pm, Tuesday
September 9, 2008

301 CSL
(Please note room change)