PhD Thesis Defence


"Multimedia Access Protocols for Shared Medium Networks"

By

Mr. Lixin Wang


Abstract

In shared medium networks, the design of the Medium Access Control (MAC)
protocol is the most crucial and challenging aspect for these networks
since the decisions made at this level will determine the major functional
characteristics of the network and set the upper limits of its
capabilities in general. In particular, it will determine the capability
of the network in providing quality of service (QoS). Most of previously
proposed protocols are not suitable for multimedia applications because
they have been designed with one generic traffic type in mind.  They
perform quite well for the traffic types they have been designed for, but
poorly for other traffic streams with different characteristics.

The objective of this thesis is to propose a methodology and framework for
integrating different MAC protocols into a single shared medium network to
efficiently accommodate various types of multimedia traffic streams with
different characteristics and QoS demands. The proposed protocol, termed
Multimedia Medium Access Control (Multimedia-MAC) protocol, is proven to
efficiently and simultaneously serve three types of multimedia traffic
streams including CBR, VBR and ABR type traffic.

We have developed a priority queuing system with vacation model to
establish a mathematical framework for the analysis and performance
evaluation of our Multimedia-MAC protocol in addition to using extensive
computer simulations, by adopting an efficient approximation approach to
numerically resolve this complicated model.  We use this analysis result
to estimate the QoS for the multimedia streams on a given shared medium
network. This estimation results in more efficient admission control which
is built-up on the basis of our Multimedia-MAC protocol.

We have applied our Multimedia-MAC approach to two widely different
networks: A wavelength division multiplexing network and a wireless
network. We have demonstrated that our Multimedia-MAC protocol design
approach is general enough to be used in various shared medium networks,
able to satisfy the QoS requirements of various mixes of multimedia
traffic streams, and outperforms state-of-the-art MAC protocols.


Date:			Thursday, 30 August 2001

Time:			10:00a.m.-12:00noon

Venue:			Room 3598
			Lifts 27-28

Chairman:		Dr. Yundong Wu (CHEM)

Committee Members:		Dr. Mounir Hamdi (Supervisor)
			Dr. Gary Chan
			Dr. Jelena Misic
			Dr. Danny Tsang (ELEC)
			Dr. Chunming Qiao (Comp., Sci. & Engg., SUNY at Buffalo)


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