SUBJECT E3)

In the early ATM days terrestrial data communications people laughed at the idea of ATM over Satellite technology. But there are organizations and researchers working on applying cell-relay technology in a satellite environment. More is being done as time goes on. Initially with using existing Satellites as raw bandwidth. In the next few years expect to see new communications satellites with on board cell processors to do some sort of cell switching between downlinks.

One place to to check out for ongoing work is the NASA ACTS Satellite ( http://kronos.lerc.nasa.gov/acts/acts.html); it can do OC-12 (4 separate OC-3's) between two ground stations. George Schmitt (george@cmf.nrl.navy.mil) reports to have run ATM videoteleconferencing hardware we built over it between Seattle and Cleveland, with 100 Mbps data in each direction. The transmission is up around 26 GHz and the ground stations put out ~53 dBm (into the directional dish). More info at the web site.

Data Communications April '96 issue had a relevent article titled 'Trials and Tests; Cell-estial ATM', starting on page 117. This lists several trials of ATM over Satellites. A brief summary follows:

• AKT Technical Trial -- AT&T, KDD, Telstra -- 45 Mbps between Australia, Japan, and US
• Aries -- NASA, etc. -- 2 Mbps between Gulf of Mexico and Pasadena
• NTN (National Test Network) -- Telesat, Bell Canada, CRC, etc. -- 8 Mbps across Canada (?)
• Northwest Telecom Trial -- Northwest Telecom, suppliers -- 8 Mbps across Northern Canada
• ESA Switched VSAT -- ESA, SAIT, ABB Nera, MPR -- E1 between Spain, Netherlands, and Germany
• Icaros -- Swiss Telecom, Telefonica de Espana, Telia AB -- 34 Mbps between Basel and Madrid
• RACE Expert -- Ascom, Swiss Telecom -- 2 Mbps in Basel

William D. Ivancic reports that the NASA Lewis Research Center performed an ATM over satellite quality of service test in support of the satellite industry and international standard making bodies such as the ITU. Surf their WEB site at http://sulu.lerc.nasa.gov/ctdreps.html. Experimental results for ATM over satellite quality of service tests using Motion-JPEG results are available to download. Parameters that were varied including BER and Eb/No. Measurements were performed on Cell Loss and Cell Errors.

Other URLs which may have ATM over Satellite information include:

• http://www.msc.edu/aries/
• http://www.ee.surrey.ac.uk/Personal/T.Ors/atmsat.html ATM over Satellite Page
• http://www.cis.ohio-state.edu/~jain/cis788/wireless_atm/index.html Wireless ATM (Ohio State)
• http://www.cam-orl.co.uk/radio.html Wireless ATM (Olivetti)

Some ATM over satellite work was done as early as 1993. COMSAT for example conducted an ATM over satellite demonstration back in September 1993 and they believe they were the first to do so. The demonstration used a transportable earth station set up at DISA Headquarters in Arlington Virginia, space segment via the SBS 2 satellite, with the other end at their Gateway station located at Clarksburg, MD. Completing the demonstration, the Gateway was connected by fiber optic link to the NAVAL RESEARCH LAB in the south part of Washington DC. The end-to-end rate was 45 mbps. They had fore ATM switches at each end connected to numerous SUN Sparc workstations. Two applications ran on the system, a telemedicine application with Doctors from Walter Reed and a mission planning application using Defense Mapping Agency Three Dimensional software. During the same period, we they also ran some experiments using a "Link Enhancer" developed by Dr. Chitre of COMSAT Labs. The demonstration ran for two weeks and many high ranking people saw it including Dr. Gibbons, the President's Science Advisor.

In 1997, Sprint began testing COMSAT World Systems' satellite-based ATM service with Hong Kong Telecom and Taiwan's Chunghwa Telecom Co. Ltd. The ATM-via-satellite trial is expected to be expanded to Thailand and Singapore by the end of the test period. The trial represents one of the earliest tests of multipoint ATM via satellite among multiple carriers. COMSAT initiated commercial ATM satellite services in March 1997, supporting speeds up to DS-3.

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