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

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

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.

Orbits GEO Geostationary (or geosynchronous) : –36000 km MEO Medium Earth Orbit : – km LEO Low Earth Orbit : – < 1500 km

Coverage

Broadcast

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

On Board Processing (Switching) –One bond x

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

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

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

Terminals

Coverage and antennas

Africa and West Asia

SkyBridge 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

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

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

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

References Aleniaspazio EuroSkyWay Globalstar SkyBridge Teledesic Sky Station Eutelsat constellations/orbcomm.htmlhttp:// constellations/orbcomm.html