Rseaux et Tlcommunications

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 (gt 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
• lt 1500 km

6
Coverage
7
Broadcast
8
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
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 ( lt 500)
• 20 Mbps down-link / 2 Mbps up-link per
  residential user
• 100 Mbps down-link / 10 Mbps up-link per business
  user

17
Teledesic Project

• Bill Gates (Microsoft)
• Craig McCaw (McCaw Cellular now sold to ATT)
• 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
(No Transcript)
19
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

20
e-BIRD 1

• Eutelsat, Paris
• Boeing satellite
• Ariane 5 launch Sep. 2003
• Operational Nov. 2003
• Internet broadband service

21
References

• Aleniaspazio EuroSkyWay
• Globalstar
• SkyBridge
• Teledesic
• Sky Station
• Eutelsat
• http//www.ee.surrey.ac.uk/Personal/L.Wood/constel
  lations/orbcomm.html