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Government and industry teams in the United States and Japan have begun a series of experiments to test the transmission of high definition video (HDV), computer data, high resolution images and video signals over the Pacific Ocean via an unprecedented combination of satellite links and fiber optic cable.

If successful, the experiments could lead to the creation of new, high-performance global telecommunications networks, said Edison Hsu, High Definition Video experiment coordinator at NASA's Jet Propulsion Laboratory, which is coordinating the U.S. portion of the tests on behalf of NASA. A number of these tests, including an experiment currently under way, are planned for coming years to develop techniques, standards, and protocols for the satellite transmission of high data rate images and scientific data, which until now have been transmitted solely via fiber optic cable.

The first experiment, currently being conducted, tests the ability of satellites to carry high-definition video signals from Tokyo to California, for such potential applications as transcontinental editing of movies and television programs shot on HDV and transmission of HDV features directly to movie theaters. Specific goals include sending and receiving images back and forth across the ocean in real time using a moderate amount of compression, and sending master tapes back and forth in slightly less than real time without any compression.

For this experiment, a Sony Research Laboratory facility in Tokyo is now linked via fiber optic cable to an Earth station in Otemachi, then to the GTE Hawaiian Tel Earth station in Hawaii via an Intelsat satellite, from there to a Earth station at the Tripler Army Medical Center in Hawaii via fiber optic cable, from Hawaii to a downlink at JPL's Woodbury Supercomputer Center in Altadena, CA, via NASA's Advanced Communications Technology Satellite (ACTS) and, finally, via fiber optic cable to the Sony Pictures High Definition Center in Culver City, CA.

"These experiments, the result of cooperative work by participants in Japan and the U.S., are indeed an exciting beginning in the demonstration of the crucial role satellites can play in the Global Information Infrastructure, or GII," Hsu explained. "They are designed to establish a broadband ATM link via satellite. This means that we can have a high bandwidth link comparable to that provided by fiber optic cables even in areas where a fiber optic infrastructure is not available or feasible, such as within or over oceans, rain forests or deserts."

Added JPL Deputy Section Manager Dr. Larry Bergman, one of the experiment's principal investigators, "These experiments are being performed at the high data rates normally transmitted by fiber optic cables, 45 to 155 million data bits per second. They are aimed at very high quality of service, about one error in a billion bits. It is our expectation that these satellite links will be comparable to fiber optics, and it is our hope that these experiments will demonstrate the striking capabilities of satellites and help us close the performance gap between these two important technologies."

Potential applications of the new networks include astronomy, telemedicine, tele-education, digital libraries and electronic commerce. The experiments will help to determine the types of upgrades of the satellite and fiber optic infrastructure that will be necessary before such applications can be practical.

NASA and Japan's Communications Research Laboratory are key sponsors of the experiments, which have been jointly organized by the Japan-U.S. Science, Technology and Space Applications Program (JUSTSAP) Working Group on Satellite Communications and the GII Satellite Quadrilateral Working Group.

Among the companies and institutions contributing facilities and services are COMSAT World Systems, George Washington University, GTE Hawaiian Tel, Intelsat, Kokusai Denshin Denwa Co., Ltd. (Japan's international phone carrier), Mitsubishi Electric Corp., Nippon Telephone and Telegraph, Lockheed Martin, Pacific Bell, Pacific Space Center, Sony Corp., Sony Pictures Entertainment High Definition Center and the State of Hawaii's Dept. of Business, Economic Development and Tourism.

The European Space Agency and the Canadian government have agreed to participate in future experiments and several Asia Pacific nations are expected to join in as well. As the experiments progress in complexity, additional satellite and cable networks will be employed. The experiments have been incorporated into an international project, Global Interoperability for Broadband Networks (GIBN), sponsored by the G-7 leading economic nations.

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