Coordination For Satellite Networks

Presentation / Coordination For Satellite Networks

Date Submitted: 02 October 2001

Written by RPC Telecommunications. Website:

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Covers topics including Satellite Coordination Background, Satellite - Terrestrial and Satellite - Satellite Coordination and the role of the ITU in coordination.

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 Printable Version
-Section 1
Satellite Coordination Background
-Section 2
What Is Coordination?
-Section 3
Key Issues
-Section 4
Frequency Allocations
-Section 5
Satellite - Terrestrial Coordination
-Section 6
Satellite - Satellite Coordination
-Section 7

What Is Coordination?

Before an “administration” allows an operator to commence operation of a new network it must in principle undergo coordination. This involves the following steps:
  • Inform other operators about the plans
  • Receive comments if appropriate
  • Conduct technical discussions with priority networks
  • Agree technical and operational parameters
  • Gain international recognition and protection on the Master
  • International Frequency Register
  • Bring the network into use

Coordination thus ensures:

  • All administrations know the technical plans of other administrations
  • All operators (satellite and terrestrial) have the opportunity to determine if unacceptable interference is likely to be caused to their existing and planned “priority” networks
  • An opportunity to object
  • An opportunity to discuss and review
  • An opportunity to reach technical and operational sharing agreements
Digression: ITU Priority
Coordination is closely bound to "date of protection" or "priority", defined by the date on which complete coordination data is received by the ITU. New planned networks must coordinate with all networks with an earlier “date of protection” but are protected against all networks with a later "date of protection". Planned (but not implemented) networks acquire status under this procedure but time limits ensure that protection is not for ever if networks are not implemented.
Interference Paths For Satellite Coordination
Frequencies can be used for both satellite and terrestrial networks. The same frequency can (in some cases) be used for satellite uplinks and downlinks. Therefore there are 6 paths by which a satellite network transmitter can cause interference to a satellite or a terrestrial receiver.

This lecture will focus only on paths 1 - 4.

Coordination And Interference
Coordination is thus concerned with:
  • Assessing the potential for interference along these paths
  • Determining if such interference is unacceptable
  • Finding conditions to resolve the interference
  • Technical conditions: limiting power, power density, coverage, etc.
  • Operational conditions: frequency planning, time-domain sharing, etc.
Why Is Satellite Coordination Important?
Coordination may seem like a rather arcane and specialist activity, and maybe not the most important aspect of network planning but for satellite networks, frequency coordination is critically important. Over-filing can mean that coordination constraints make a network unusable so coordination tends to mean if and not how. Satellite projects are increasingly driven not by financial/marketing/construction etc. but by coordination!

Next: Section 3 - Key Issues


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