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Réseaux et Télécommunications

Réseaux et Télécommunications. 4 - Introduction aux réseaux par satellite Edoardo Berera Telelinea. Plan. Orbits and coverage: GEO, MEO, LEO Broadcast, point-to-point “Bent-pipe” vs. on-board processing Examples Iridium Globalstar EuroSkyWay SkyBridge Teledesic Sky Station e-BIRD 1 .

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Réseaux et Télécommunications

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  1. Réseaux et Télécommunications 4 - Introduction aux réseaux par satellite Edoardo Berera Telelinea

  2. Plan • Orbits and coverage: GEO, MEO, LEO • Broadcast, point-to-point • “Bent-pipe” vs. on-board processing • Examples • Iridium • Globalstar • EuroSkyWay • SkyBridge • Teledesic • Sky Station • e-BIRD 1

  3. Satellites • From Sputnik... to military • Since the first russian Sputnik satellite in 1957 : • 5000 satellites have been launched • 2500 are still in orbit • Half of them are used by the military

  4. Civilian usage • The remaining ones (> 1200) are used for: • telecommunications (Telecom-1, Telecom-2,...) • television (Astra, HotBird 5, ...) • meteorology (Meteosat, Med Hycos) • earth observation (Landsat, Spot) • astronomy (Hubble) • 2000 are expected to be launched in the next 10 years, including a number of satellite constellations.

  5. Orbits • GEO Geostationary (or geosynchronous) : • 36000 km • MEO Medium Earth Orbit : • 1500 - 10000 km • LEO Low Earth Orbit : • < 1500 km

  6. Coverage

  7. Broadcast

  8. X “Bent Pipe” (Mirror) • VSAT Very Small Aperture Terminal • Terrestrial Switching Center • Two bonds

  9. On Board Processing (Switching) • One bond x

  10. Iridium • Consortium: • Motorola main contractor • Operational service since November 1998 • $ 5 bn, 7 years • 66 LEO fast-moving satellites (+ 14 spares), • 780 km • Unique inter-satellite "cross-links" • 11 earth stations

  11. Globalstar • Consortium • Loral Space and Communications • Qualcomm • France Telecom • Vodafone Group (UK) • Hong Kong Telecom • Service operational since September 1999 • $ 3 bn • 48 LEO satellites (+ 4 back-up), 1400 km • 50 earth stations • Primary market is "cellular network extension" • Call price: 0.70 €/min

  12. EuroSkyWay • Aggregate capacity • 45 Gbps • cluster of five satellites • geostationary satellites • Digital on-board processing (OBP) • Inter-satellite links (ISL) • Alenia Aerospazio

  13. Terminals

  14. Coverage and antennas

  15. Africa and West Asia

  16. Consortium: Alcatel Loral Space & Communications Toshiba Mitsubishi Constellation 80 LEO satellites 1469 km Space segment cost: $4.2 bn Ground segment cost: $1.9 bn By working through local operators, SkyBridge is positioned as a local access system, “DSL in the sky” solving the "last mile problem" as well as providing Universal Service worldwide low cost terminals ( < $500) 20 Mbps down-link / 2 Mbps up-link per residential user 100 Mbps down-link / 10 Mbps up-link per business user SkyBridge

  17. Teledesic Project • Bill Gates (Microsoft) • Craig McCaw (McCaw Cellular now sold to AT&T) • Prince Alwaleed of Saudi Arabia • Boeing and Motorola • Initially 840, now down to 288 LEO satellites at 700 km • $ 9 bn • Subscribers service at 64 Mb/s downlink and 2 Mb/s uplink • Broadband terminals at 64 Mb/s bidirectional

  18. Sky Station Project • Telecommunications • Earth Sciences Applications • 250 Sky Stations (157 x 62 m) • 22 km (stratosphere) • coverage 20 000 km2 • 2 - 10 Mb/s • Alenia Aerospazio • Thomson-CSF • Daimler-Benz Aerospace • COMSAT Laboratories • United Solar Systems Corp

  19. e-BIRD 1 • Eutelsat, Paris • Boeing satellite • Ariane 5 launch Sep. 2003 • Operational Nov. 2003 • Internet broadband service

  20. References • Aleniaspazio EuroSkyWay • Globalstar • SkyBridge • Teledesic • Sky Station • Eutelsat • http://www.ee.surrey.ac.uk/Personal/L.Wood/constellations/orbcomm.html

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