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Speaker:        Dr. Bo Li
                Department of Computer Science
                Hong Kong University of Science & Technology

Topic:          "An End-to-End Adaptation Protocol for Layered
                 Video Multicast"

Date:           Monday, 8 April 2002

Time:           4:00pm - 5:00pm

Venue:          Lecture Theater F
                (Leung Yat Sing Lecture Theater, near lift nos. 25/26)
                HKUST

ABSTRACT:

Layered transmission has been proposed as a solution to video multicast
over the Internet. Existing protocols usually perform adaptation at the
receiver's side and use static rate allocation techniques at the sender's
side. As a result, significant mismatches between the fixed transmission
rates and the heterogeneous and dynamic rate requirements from the
receivers could still occur.

In this talk, we first show that such mismatches can be minimized by
employing dynamic layer rate allocation at the sender's side by taking
advantage of the recent development in layered video coding. Specifically,
we study the optimisation criteria for layer rate allocation, and propose
a metric called Application-aware Fairness Index. This metric takes into
consideration of  1) the non-linear relation between the perceived video
quality and the delivered bandwidth, and  2) the degree of fairness in
term of receiver's satisfaction with heterogeneous bandwidth requirements.
We formulate the rate allocation into an optimisation problem with the
objective of maximizing the expected fairness index for all receivers in a
session, and derive an efficient and scalable solution using dynamic
programming. We further demonstrate that such an optimal sender rate
allocation can be seamlessly integrated into an end-to-end adaptation
protocol called HALM (Hybrid Adaptation Layered Multicast). This protocol
is designed for the current best-effort Internet and is TCP-friendly.

This is a joint work with my PhD student Jiangchuan Liu, and Dr. Ya-Qin
Zhang of Microsoft Research, which will appear in IEEE Infocom'2002, New
York City, June 23-27, 2002.



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Biography:

Bo Li received the B.S. and M.S. degrees in the Computer Science Dept.,
from Tsinghua University, Beijing, with honors, and the Ph.D. degree in
the Computer Engineering from University of Massachusetts at Amherst.
Between 1994 and 1996, he worked on high performance routers and ATM
switches in IBM Networking System Division, Research Triangle Park, North
Carolina. Since then, he has been with the Computer Science Department,
the Hong Kong University of Science and Technology.

His current research interests include wireless mobile networking
supporting multimedia, video multicast and all optical networks using WDM.
He co-authored the first paper on internet proxy server placement (1999).
He has been active in the research community, particularly in IEEE and
ACM, and has published over 40 journal papers, served as an editor or
guest editor for over 10 journals in related areas, such as IEEE
Transactions on Wireless Communications, IEEE Transactions on Vehicular
Technology, ACM/Kluwer Journal of Wireless Networks (WINET), IEEE Journal
on Selected Areas in Communications, and IEEE Communications Magazine. In
addition, He has been involved in organizing over 30 conferences, esp.
IEEE Infocom since 1996.


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