Basic Satellite Communication (5) Ground Segment and Practical Aspects of SatCom

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Basic Satellite Communication (5)Ground Segment
and Practical Aspects of SatCom

• Dr. Joseph N. Pelton

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Typical VSAT System(Very Small Aperture
Terminals)

• Applications
• Credit Card Validation
• ATM/Pay at the Pump
• Inventory Control
• Store Monitoring
• Electronic Pricing
• Training Videos
• In-Store Audio
• Broadband Internet Access
• Distance Learning

Apartment Buildings
Corporate Offices
Residential
Gas Stations
Corporate Data Center
Branch offices
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Key Trends for Satellite and User Terminals

• Satellite in general are becoming more capable,
  with higher power and larger aperture antennas to
  promote frequency re-use and higher flux density.
  Thus satellites are increasingly massive (due to
  antenna and power systems) but are, in essence,
  highly capable super-computers-in-the-sky with
  specialized digital software.
• This allows user terminals to become smaller,
  lighter in weight and still handle broader band
  services. This is sometimes called technology
  inversion. Overall systems costs have decreased
  because of the explosion of low cost user
  terminals that can now receive video via
  hand-held units.
• User terminals with Geo-systems do not have to be
  re-pointed, but LEO or MEO-systems must be able
  to track or have omni (or quasi-omni) antennas so
  that signals can be received from all possible
  angles.

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Key in User Terminals

• Growth in VSATs towards 1 million with virtually
  all of them optimized via new IP over Satellite
  (IPoS) standard.
• Size of VSATs has decreased from around 3 meters
  down to about 1 to 1.2 meters and costs have
  continued to decline especially driven by Digital
  Video Broadcast and DOCSIS standards that allow
  very high speed low cost links (i.e. 45 to 60
  Mbps) with return channel service (RCS) that
  allows up stream speeds in the 56 to 384 kbps
  range.

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Ground Equipment Trends

• Terminals
• Omni directional or patch antennas
• Smaller, lighter, cheaper
• Yet more capable (i.e. video signals broadband)
• Pocket, notebook, rugged
• Sophisticated (ASIC driven) yet simple
• Application specific terminals, embedded modems
• Phones
• Satellite capability 3 GSM frequencies
  video
• Voice, Asynchronous Data and Packet Data
• Smaller (antenna and battery in particular)
• Long stand-by mode

Minimal Set-Up Time, Robust, Portable, Easy to Use
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Rural Hybrid Networks

• Internet backbone distribution using satellite
  local distribution using 2.4 GHz wireless

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Satellite-Fiber ComparisonComparing Satellite
and Fiber Characteristics
Capability Fiber Optic Cable Systems Geo Satellite in a Global System Meo Satellite in a Global System Leo Satellite in a Global System
Transmission Speed 10 Gbps 3.2 Terabits/second Single Sat 1Gbps-10Gbps Single Sat 0.5Gbps-5Gbps Single Sat .01Gbps-2Gbps
Quality of Service 10-11 - 10-12 10-2 - 10-11 10-2 - 10-11 10-2 - 10-11
Transmission latency 25 to 50 ms 250ms 100-150 ms 25-75 ms
System Availability w/o Backup 93 to 99.5 99.98 (C-Ku band) 99 (Ka band) 99.9 (C-Ku band) 99 (Ka band) 99.5 (L-C-Ku band) 99 (Ka band)
Broadcasting Capabilities Low to Nil High Low Low
Multicasting Capabilities Low High High Medium
Trunking Capabilities Very High High Medium Low
Mobile Services Nil Medium-to-High High High
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Dramatic decrease in the cost of Fiber Optic
Systems
lifetime
1995
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Satellite Based IP Services Growing

• Demand for all types of IP based satellite
  services is growing including VoIP and MMIP.
• Satellite service today requires special
  spoofing systems to achieve reasonable
  transmission efficiency (85 possible with the
  best system from Mentat, ViaSat, etc. and use of
  the new IPoS standards.
• Improvements can be achieved by increasing window
  sizes to reduce misinterpretation of latency for
  system congestion, spoofing software, and other
  modifications to satellites to address IP
  Security issues.

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Satellite Lifecycle and Failure Modes

• Most failures occur at start or end of life
• Many satellite failures are due to software or
  operator errors rather than hardware failures
• Infant Failures (deployment of antenna and solar
  arrays, failure to reach proper orbit, etc.)
• End-of-Life Failures and Wear-out (MTTF)
• Bathtub Curve of Satellite Failures
• Catastrophic Failures can occur at any time.
  (Orbital debris, Electro-Magnetic Storms, Cosmic
  Rays, Micro-meteorites, etc.)

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Satellite Employment Patterns 1998-2004 (97,000
to 162,000)
190,000 170,000 150,000 130,000 110,000
105,000 100,000 98,000 96,000 0
Launch Vehicle Manufacturing of Experimental
SatCom Satellite Manufacturing Ground
Equipment Manufacturing Satellite Services
1998 1999 2000
2001 2002 2003
2004
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Satellite Technologies of the Future

• On-Board Processing
• Signal Regeneration
• Advanced Antenna Systems (hopping/scanning beams,
  phased-array, inflatable structures,
  piezo-electric systems)
• More Efficient Power Systems
• Turbo-coding
• Advanced Modems and Enhanced Vocoder Algorithms
  and Error Correction Systems

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Satellite Technologies of the Future

• More Efficient Use of Spectrum
• New Materials for Light Weight Antennas and
  Satellite Construction
• Advanced Orientation and Propulsion Systems (and
  Autonomous Operation)
• Advances in Launch Systems
• USATs, VSATs, Micro-terminals (MEMS ASIC
  break-throughs)

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Course Review

• Satellite Services and Markets (Overview)
• Development of Satellite Technology from the
  1960s onward
• Basic Elements of Satellite Transmission
• Satellite Orbits (Pros and Cons)
• Satellite Frequencies and Spectrum Allocation
• Key Satellite Terms Concepts

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Assignment

• Assignment 6
• Write short notes on the terms highlighted in
  yellow color