Characterization and Optimization of Delay Guarantees for Real-Time Multimedia Traffic Flows in IEEE 802.11 WLANs
Abstract: Due to the rapid growth of real-time applications and the ubiquity of IEEE 802.11 MAC as a layer-2 protocol for wireless local area networks (WLANs), it becomes increasingly important to support delay-based quality of service (QoS) in such WLANs. In this paper, we develop a simple and accurate enough analytical model for predicting the queueing delay of real-time multimedia traffic flows in nonhomogeneous random access based WLANs. This leads to tractable analysis for meeting queueing delay specifications of a number of flows. In particular, we address the feasibility problem of whether the mean delays required by a set of User Datagram Protocol (UDP) flows supporting real-time multimedia traffic can be guaranteed in WLANs. Based on the model and feasibility analysis, we further develop an optimization technique to minimize the delays for the traffic flows. Moreover, we present a decentralized algorithm and report its implementation and present extensive simulation and experimental trace-based results to demonstrate the accuracy of our model and the performance of the algorithms.