The Japan Aerospace Exploration Agency (JAXA) together with the Japan National Institute of Information and Communications Technology are planning to launch a
new communication satellite called the Wideband Internetworking Engineering Test and Demonstration Satellite (WINDS) in 2007. The WINDS satellite will provide high-speed data communication for the Asia Pacific
countries including Hong Kong with a goal to promote the use of satellites in such fields as Internet communications, education, medicine, disaster measures and Intelligent Transport Systems.
Over the past several years we have been participating in the international collaboration efforts organized by JAXA and we have been granted access to the WINDS satellite to conduct
research and experiments. This project aims at leveraging the access to the WINDS satellite for the research and experiment of multimedia content multicasting over the WINDS satellite system. This project has two
objectives. The first objective is to explore new research opportunities and to tackle the research challenges in delivering high-bandwidth multimedia contents such as audio and video to a large number of users
across multiple countries and regions. The second objective is to offer a content distribution platform for JAXA WINDS members to multicast research, cultural, and educational contents to other JAXA WINDS members as
well as ordinary Internet users.
2. Research and Development
The current Internet does not yet support multicast transmission over a global scale. Therefore distributing high-quality multimedia contents to a
large number of users is still very costly. By contrast, satellite communication is inherently broadcast in nature and thus could offer a cost effective solution for multicasting high-quality multimedia contents.
For regions not covered directly by the satellite, we could extend the network's reach by routing and forwarding data over the terrestrial Internet. As shown in the following figure the media server sends out data
over both the satellite and the terrestrial Internet.
Given there are now two network channels available, one research challenge is on the routing of media data to a user, who may have access to either one or both of the
network channels. Beginning with the simplest routing policy, the server can simply be configured to route media data over the satellite channel whenever the user is known to
have satellite connectivity (e.g., identification via user ID or IP address). Otherwise the media data will be routed via the Internet using application-layer multicast (ALM).
Taking this idea one step further, the system can also exploit the fact that some users will have access to both network channels, and thus instead of receiving data through a fixed
network channel, can monitor the network performance and then dynamically route the data through the best-performing network channel. This idea can be extended even
further by exploring the transmission of media data over both Internet and satellite channels simultaneously – multi-path routing. This will be more complex as the
characteristics of the Internet channel and the satellite channel, in terms of bandwidth, delay, and loss, are very different. Therefore new media streaming algorithms will need
to be developed to compensate for the differences and to exploit the benefits of multi-path routing.
This research project comprises two components, namely the network communications module and the content management module. The former is the focus of this research
project while the latter will be supported by the CUHK Video Multicast Platform already developed and deployed for use in the Internet. With the CUHK Video Multicast Platform,
this project will extend it with a satellite communications module to access the JAXA WINDS satellite for multicasting media contents to JAXA WINDS members. This will enable
the system to stream media data to three types of users, namely unicast-only, multicast-ready, and satellite-ready users as shown below.
Professor Jack Y. B. Lee, Department of Information Engineering
Professor Peter T. S. Yum, Department of Information Engineeering
Japan Aerospace Exploration Agency (JAXA)
Shun Hing Institute of Advanced Engineering (SHIAE)