Scheduling and resource allocation in broadband multimedia wireless local area networks

by Kautz, Richard

SCHEDULING AND RESOURCE ALLOCATION IN BROADBAND MULTIMEDIA WEWLESS LOCAL AREA NETWORKS Richard Wayne Kautz Doctor of Philosophy in Electrical and Computer Engineering University of Toronto Two maintopics of research in modern cornputer netarorks are the development of new wireless architectures and technologies, and the addition of new multimedia services. These two topics have converged in the design of multimedia Wireles Local Area Netwotks (WLANs). The sgnthesis of wire1ess and multimedia networks has opened new problem areas in transmission scheduling and resource allocation. Techniques suitable for wireless telephony are unsuitable for a multimedia environment, and techniques for wired muitimedia networks are not immediately applicable to a wireless medium. The problems of transmission scheduling and resource allocation are explored in three areas: The-Division Multiple Access (TDMA), hybrid TDMA/ Code Division Multiple Access (CDMA) ,and multicellular TDMA environments. The problem of scheduling îs explored in TDMA networks through Distributed Fair Queueing (DFQ), a centralized scheduling protocol. The necessary concepts of Fair Queueing are reviewed, and the resource allocation problem for multimedia semces is addressed. The DFQ architecture is then introduced, and the problems due to physical and error control overhead are studied, Behaviour of a nrix of multimedia services is simulateci tO determine average system performance. The problems of Quaiity-of-Service (QoS) delivery in hybrid TDMA/Code Division Multiple Access (CDMA) are addresseci by introducing difkential power control for QoS preservation. The optimal power levels are determined in order to maximize the capaciw of the network. Two scheduling methodologies are introduced, Mering in aciency and cornpl & @. Finally, the problem of channel allocation in an unlicensed, distributecl-architecture environment is explored through a simple interfmce avoidance protocol med Active Channel Avoidance (ACA). The ACA protocol attempts to minimize interference between melated networks in an environment while allowing communication between cells of mdticellular networks. The performance of simple network models under ACA is dculated, in order to estimate performance for rd-world networb and provide a theoretical hework for hrther refinement. This thesis is dedicated to my parents, who have instilled a Lifelong !ove of leaming in me. I would like to thank my supervisors, Professors Leon-Garciaand Pasupathy, who have given me direction and constructive criticism throughout my program.