March 15, 2000

Mr. Donald Abelson

Chief of the International Bureau

Federal Communications Commission

Washington, D.C. 20554

Dear Mr. Abelson:

The National Telecommunications and Information Administration on behalf
of the Executive Branch Agencies, has approved the release of an
additional proposal for WRC-2000. The enclosed proposal considers
WRC-2000 Agenda Item 1.13.1. This agenda item is concerned with the
revision of the power limits appearing in Articles **S21** and **S22**
in relation to the sharing conditions among non-GSO FSS, GSO FSS, GSO
broadcasting-satellite service (BSS), and space science and terrestrial
services, to ensure the feasibility of these power limits and that these
limits do not impose undue constraints on the development of these
systems and services.

The purpose of this proposal is to update the constraints related to the
operational applications and technology in the band 13.75-14 GHz. We are
modifying footnotes **S5.502** and **S5.503**, plus a new footnote
**S5.502A** is being added to address the constraints issue. These
footnote changes would retain the delicate balance between the space
research, fixed-satellite, radiolocation, and radionavigation services
agreed to at **WARC-92** and confirmed at **WRC-95**. Since the earlier
technical studies did not account for non-GSO systems, their allocations
requirements are redefined. Technical studies have shown that non-GSO
receiving space stations will be susceptible to interference from
radiolocation and radionavigation stations operating in accordance with
the ITU radio regulations.

Karl Nebbia from my staff will contact Damon Ladson and reconcile any
differences.

> Sincerely,

###### 

> *Original Signed*
>
> William T. Hatch
>
> Associate Administrator
>
> Office of Spectrum Management

Enclosure

United States of America

proposals for the work of the conference

# Proposal for Agenda Item 1.13.1

## on the basis of the results of the studies in accordance with Resolutions 130 (WRC-97), 131 (WRC-97) and 538 (WRC-97): to review and, if appropriate, revise the power limits appearing in Articles S21 and S22 in relation to the sharing conditions among non-GSO FSS, GSO FSS, GSO broadcasting-satellite service (BSS), space science and terrestrial services, to ensure the feasibility of these power limits and that these limits do not impose undue constraints on the development of these systems and services;

### Proposal to update the constraints related to the operational applications and technology in the band 13.75-14 GHz (MOD S5.502, ADD S5.502A and MOD S5.503)

**Background Information:** At WARC-92 and as modified at WRC-95, Nos.
**S5.502**, **S5.503** and **S5.503A** were added to the Table of
Frequency Allocations to facilitate compatibility between the existing
applications of the radio services in the 13.75-14 GHz band. It was
agreed that any modifications to any of these footnotes in order to
accommodate new technology, new requirements and applications of the FSS
should consider the overall interference environment in the 13.75-14 GHz
band and be undertaken with great care in order to avoid upsetting the
delicate balance previously achieved between the services. The present
operational constraints, that satisfy the protection criteria of current
operational applications and technology in the band 13.75-14 GHz, are to
be found in Nos. **S5.502** and **S5.503**.

Studies that led to the development of these footnotes did not account
for non-geostationary-satellite orbit fixed-satellite service systems
(non-GSO FSS). With the introduction of non-GSO FSS into this band at
WRC-97, Resolution **130 (WRC-97)** was, among other things, drafted to
focus attention on the need to reexamine the sufficiency of these
footnotes in maintaining the delicate balance between the services
sharing the 13.75-14 GHz band.

Analysis of sharing between geostationary FSS and the radiolocation and
radionavigation services is contained in Recommendation ITU-R S. 1068.
Some studies have shown that sharing with radiolocation systems is
significantly more difficult for non-GSO FSS systems than for GSO FSS
systems. Other studies have shown that more restrictive e.i.r.p. density
limits are needed on non-GSO FSS systems than GSO FSS systems for
protection of space research systems. The protection criteria of the
space research links used are those included in Recommendation ITU-R
SA.1155. The CPM Report to WRC-2000 provides guidance on possible
methods for maintaining the present balance in the sharing conditions
between radiolocation, radionavigation, space science and FSS, and
accommodates non-GSO FSS systems within the 13.75-14 GHz band. The CPM
report and also studies presented at the WP4A meeting, 21-29 February
2000, do not provide any substantial evidence to relax the minimum
4.5-meter antenna diameter requirement. This requirement serves to limit
the number of FSS earth stations thus maintaining a sharing balance. It
would be premature to relax this requirement without further study. The
following proposed modifications/additions to the governing footnotes
are based on the work of the ITU-R.

**Proposal:**

+-------------+--------------------------------------------------------+
| USA/1.13/   | S5.502 In the band 13.75-14 GHz, the e.i.r.p. of any   |
|             | emission from an earth station in the fixed-satellite  |
| MOD         | service [operating with a space station in             |
|             | geostationary-satellite orbit]{.underline} shall be at |
|             | least 68 dBW, and should not exceed 85 dBW, with a     |
|             | minimum antenna diameter of 4.5 metres. In addition    |
|             | the e.i.r.p., averaged over one second, radiated by a  |
|             | station in the radiolocation or radionavigation        |
|             | services towards the geostationary-satellite orbit     |
|             | shall not exceed 59 dBW.                               |
+-------------+--------------------------------------------------------+

> **Reasons:** Footnotes **MOD S5.502, ADD S5.502A** and **MOD S5.503**
> retain the delicate balance between the space research,
> fixed-satellite, radiolocation, and radionavigation services agreed to
> at WARC-92 and confirmed at WRC-95. Since the earlier studies did not
> account for non-GSO systems, their allocations requirements are
> redefined and addressed by new footnote S5.502A. Footnote S5.502 is
> clarified to apply to geostationary-satellite orbit fixed-satellite
> service systems.

+-------------+--------------------------------------------------------+
| USA/1.13/   | S5.502A In the band 13.75-14 GHz, the e.i.r.p. of any  |
|             | emission from an earth station in the fixed-satellite  |
| **ADD**     | service operating with a space station in              |
|             | non-geostationary-satellite orbit should not exceed    |
|             | 85 dBW and shall have a minimum antenna diameter of    |
|             | 4.5 metres. Receiving space stations in                |
|             | non-geostationary satellite orbit shall not claim      |
|             | protection from radiolocation and radionavigation      |
|             | transmitting stations operating in accordance with the |
|             | Radio Regulations.                                     |
+-------------+--------------------------------------------------------+

> **Reasons:** Footnotes **MOD S5.502, ADD S5.502A** and **MOD S5.503**
> retain the delicate balance between the space research,
> fixed-satellite, radiolocation, and radionavigation services agreed to
> at WARC-92 and confirmed at WRC-95. Since the earlier studies did not
> account for non-GSO systems, their allocations requirements are
> redefined. Studies have shown that non-GSO receiving space stations
> will be susceptible to interference from radiolocation and
> radionavigation stations operating in accordance with the RR.

+-------------+--------------------------------------------------------+
| USA/1.13/   | **S5.503** In the band 13.75-14 GHz, geostationary     |
|             | space stations in the space research service for which |
| **MOD**     | information for advance publication has been received  |
|             | by the Bureau prior to 31 January 1992 shall operate   |
|             | on an equal basis with stations in the fixed-satellite |
|             | service; after that date, new geostationary space      |
|             | stations in the space research service will operate on |
|             | a secondary basis. ~~The e.i.r.p. density of emissions |
|             | from any earth station in the fixed-satellite service  |
|             | shall not exceed 71 dBW in any 6 MHz band in the       |
|             | frequency range 13.772-13.778 GHz until~~              |
|             | [Until]{.underline} those geostationary space stations |
|             | in the space research service for which information    |
|             | for advance publication has been received by the       |
|             | Bureau prior to 31 January 1992 cease to operate in    |
|             | this band~~.~~[:]{.underline}                          |
|             |                                                        |
|             | [a) The e.i.r.p. density of emissions from any earth   |
|             | station in the fixed-satellite service operating with  |
|             | a space station in geostationary-satellite             |
|             | orbit]{.underline} [shall not exceed 71 dBW in any 6   |
|             | MHz band in the frequency range 13.772-13.778          |
|             | GHz;]{.underline}                                      |
|             |                                                        |
|             | [b) The e.i.r.p. density of emissions from any earth   |
|             | station in the fixed-satellite service operating with  |
|             | a space station in non-geostationary-satellite orbit   |
|             | shall not exceed 51 dBW in any 6 MHz band in the       |
|             | frequency range 13.772-13.778 GHz.]{.underline}        |
|             |                                                        |
|             | Automatic power control may be used to increase the    |
|             | e.i.r.p. density ~~above 71 dBW~~ in any 6 MHz band in |
|             | this frequency range to compensate for rain            |
|             | attenuation, to the extent that the power flux-density |
|             | at the fixed-satellite service space station does not  |
|             | exceed the value resulting from use of an e.i.r.p. of  |
|             | 71 dBW [or 51 dBW, as appropriate,]{.underline} in any |
|             | 6 MHz band in clear sky conditions.                    |
+-------------+--------------------------------------------------------+

> Reasons: Footnotes **MOD S5.502, ADD S5.502A** and **MOD S5.503**
> retain the delicate balance between the space research,
> fixed-satellite, radiolocation, and radionavigation services agreed to
> at WARC-92 and confirmed at WRC-95. Since the earlier studies did not
> account for non-GSO systems, their allocations requirements are
> redefined. Studies have shown that an e.i.r.p. density limit of 51
> dB(W/6 MHz) on non-GSO fixed-satellite service earth station emissions
> will facilitate co-equal sharing with the space research service.

\_\_\_\_\_\_\_\_\_\_\_\_\_