***RCS WRC --07 Agenda Item Scope and High-Level Work Plan***[^1]

**Agenda Item 1.18**: to review pfd limits in the band 17.7-19.7 GHz for
satellite systems using highly inclined orbits, in accordance with
Resolution **141 (WRC‑03)**;

**Short Description:** Resolution **141 (WRC-03),** asks to conduct
studies to determine if the pfd limits in Article 21 for certain types
of non-geostationary satellite systems using highly-inclined orbits are
adequate to protect the fixed service in the 17.7-19.7 GHz band.

**Background:** At WRC-2003, France insisted that their fixed-service
(FS) systems need more protection from highly-inclined non-geostationary
satellites than from circular orbit non-geostationary satellites since
highly-inclined satellites can remain over a service area longer than a
circular orbit satellite. Article **21** power flux density limits were
modified at WRC-2000 to protect the FS from all non-geostationary
satellites (France claims that highly-inclined orbits were not
considered in the studies). A small number of highly-inclined
non-geostationary orbit satellite systems have operated successfully in
the fixed-satellite service (FSS) for over 10 years, including in the
17.7-19.7 GHz band. Currently, France claims that they need to tighten
the pfd values by up to 30 dB, while the US believes that the current
pfd limits are adequate.

Resolution **141 (WRC-03)** also asks to determine if there are
technical and operational measures that could be implemented in the
fixed service in the band 17.7-19.7 GHz to mitigate interference for the
FSS.

**Interested Countries:** France, Norway, Japan and UK are the biggest
proponents of modifying the pfd limits. So far, no administration has
raised its support for the US position of no modification of the pfd
limits.

**Agenda Item Scope:** Studies for **t**his agenda item are expected to
encompass non-GSO systems using highly inclined orbits and fixed service
systems operating in the 17.7-19.7 GHz band. An unresolved issue is
whether non-GSO systems using circular orbits but meeting the apogee and
inclination limits described in *considering g* of Resolution 141
(WRC-03) should be considered as systems using highly inclined orbits
and be included in the studies. France, Norway, and UK are in favour of
including non-GSO system with circular orbits while Canada currently
supports the US position of not including them.

Within the US, DoD has been the only entity operating a non-GSO system
in the band of interest. However, two commercial companies have recently
filed with the FCC to operate their own non-GSO systems in the band.

**Key technical issues to be resolved:** Are the current pfd limits in
Article **21** adequate to protect the fixed service from the non-GSO
systems using highly inclined orbits in the 17.7-19.7 GHZ band? In order
to answer this question, the number of non-GSO systems used in the
studies needs to be determined. Past studies have used numbers of
systems as high as 30 whereas the US believes the number should be as
low as 2.5 systems. Also, a determination needs to be made on including
non-GSOs using circular orbits.

Also, practicable mitigation measures, both technical and operational,
need to be determined.

**Key policy issues to be resolved:** None. The federal government and
the commercial satellite community are in accord on this agenda item and
support no change as the US position.

**Work Plan and Organization Participation:** Work to be completed in
support of this agenda item is as follows:

1.  Conduct studies to validate that the current pfd limits are adequate
    to protect the fixed service from non-GSO systems using highly
    inclined orbits in the 17.7-19.7 GHz band.

2.  Study mitigation measures and determine effective and practical
    means to protect the fixed service from non-GSO systems using highly
    inclined orbits in the 17.7-19.7 GHz band.

The responsible group for this agenda item is WP 4-9S, with WP 4A, WP
9A, and WP 9D as contributing groups. Government contributors are: Jerry
Conner, ITT Industries for DoD OSD/NII, and Gary Chinault, DISA/DSO.

[^1]: **Author**: Jerry Conner **Document Date**: May 24, 2004