PhD Thesis Proposal Defence


"Wireless Video: Modeling and Performance Study"

By

Mr. Jian Zhao


Abstract

With the emergence of advanced video encoding technology and the rapid
deployment of broadband wireless networks, high quality wireless video
services become increasingly feasible. Transporting of video traffic over
the broadband wireless networks is likely to be a dynamic industry.
A critical issue for multimedia applications on wireless is to ensure
that the quality-of-service (QoS) is maintained at an acceptable level.
Furthermore, this QoS must be ensured under unreliable and time-varying
wireless channels. Thus it is particularly important to develop analytical
performance model for wireless video transmission systems.

In this research we examine the link level performance of video
transmission over the uplink of an unreliable wireless channel.
We formally define the discrete time batch Markovian arrival process
(DBMAP) with marked transitions. We show that the marked DBMAP can
be used to model video traffic such as MPEG-4, taking into account
the inherent nature of the adaptiveness of the video traffic.
We propose a priority based scheduling protocol with automatic
retransmission request (ARQ) control for video data transmission,
by taking advantage of the scalability of MPEG-4 video traffic.
We prove that in a hidden Markov modeled (HMM) wireless channel with
probabilistic transmission, the service time for an arbitrary radio link
control (RLC) data burst follows discrete time phase (PH) type
distribution.

Extensive simulations are carried out to study the queueing behavior
of the video data transmission buffer, as well as the error and drop
behavior at both the RLC burst and video packet level. The results
demonstrate that the proposed priority scheduling and ARQ control
protocol can substantially improve video quality by preserving the
high priority video data during the transmission.
Based on the marked DBMAP arrival process and the PH type service,
we obtain a DBMAP/PH/1 priority queue. We plan to extend this research
by studying the underlying Markov chain of the DBMAP/PH/1 priority queue,
develop computation algorithms for the probability distribution of the
number of jobs in the system. We will derive the key performance indices
of the queueing model. We will also study video traces with layered coding
and develop a traffic model for scalable video encoded in multiple layers.
The model will be based on the marked DBMAP process.


Date:				Friday, 25 October 2002

Time:				3:30p.m.-5:30p.m.

Venue:				Room 3315
				Lifts 17-18

Main Supervisor:		Dr. Ishfaq Ahmad

Committee Members:		Dr. Bo Li (Supervisor)
				Prof. Dik-Lun Lee (Chairman)
				Dr. Brahim Bensaou
				Dr. Michael Brown


**** ALL are Welcome ****