Towards the Personal Communicator

Presentation / Towards the Personal Communicator

Date Submitted: 06 June 2001

Written by RPC Telecommunications. Website: http://www.rpctelecom.com

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A short lecture presented to the Surrey Section of the IEE (the IEE is the British Institution of Electrical Engineers) by Mark C J Posen of RPC Telecommunications Ltd.

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 Printable Version
-Section 1
"Beam Me Up Scottie"
-Section 2
Concept
-Section 3
Orbit Mechanics
-Section 4
Iridium
-Section 5
ICO
-Section 6
Globalstar
-Section 7
Implementation & The Future

Orbit Mechanics

SLIDE 11

Digression - Orbit Mechanics!

Notes:
By way of a digression lets look at some orbit mechanics! This figure shows a generalised orbit... remember Kepler from school! The planet is at one focus... orbiting body sweeps out equal areas in equal time... define apogee, perigee, period, inclination mention stability

SLIDE 12

Orbit Mechanics (2)

  • Geostationary (GSO/GEO) - 36,000 km / 24 hour period / <5 inclination
  • Geosynchronous (GSO/GEO) - as stationary but higher inclination
  • Low Earth Orbit - <2,000 km / 80 - 130 minutes period
  • Medium (Intermediate) Earth Orbit - 2,000 km - 10,000 km / 130 minutes - 6 hours period

Notes:
Here are the main classes of orbit...

SLIDE 13

Orbit Mechanics (3)

-Other orbits

  • Inclined Highly Elliptical (HEO)
  • Sub- and super-synchronous

-Combine orbits into "constellations"

  • groups of orbits to provide global or regional coverage
  • key to defining service characteristics

Notes:
...and here are a few more! The CONSTELLATION puts a number of satellites together to provide a COVERAGE.

SLIDE 14

Concept (6) - Network Configuration

-There is no "typical" S-PCN configuration

-Some things to be considered: 

  • routing in space or on the ground (ISLs?)
  • integrated into terrestrial network / overlay / stand-alone?
  • gateway distribution... politically difficult!

We'll not try and answer these now but will look at specific proposals...

Notes:
Let's touch on the network configuration. This is complex and could be an entire lecture in itself! Mention some key considerations. (slide)

SLIDE 15

Proposals (1)

We'll focus on three specific examples

Bear in mind some of the key issues:

  • NGSO vs. Super-GEO
  • CDMA vs. TDMA
  • ISL vs. non-ISL

Next: Section 4 - Iridium

 
 

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