Mr. John Giusti

Chief of the International Bureau

Federal Communications Commission

445 12th Street SW

Washington, D.C. 20554

Dear Mr. Giusti:

The National Telecommunications and Information Administration (NTIA),
on behalf of the Executive Branch Agencies, has approved the release of
an additional draft Executive Branch proposal for WRC-07. This proposal
considers the federal agency inputs toward the development of U.S.
Proposals for WRC-07.

The enclosed document contains a draft proposal, which addresses Agenda
Item 1.7 is forwarded for your consideration and review by your WRC-07
Advisory Committee. Jim Vorhies of my staff is the primary contact for
NTIA.

Sincerely,

> *(Original Signed September 27, 2006)*

Fredrick R. Wentland

> Associate Administrator
>
> Office of Spectrum Management

Enclosure

# United States of America

### PROPOSAL FOR THE WORK OF THE CONFERENCE

**Agenda Item 1.7**: to consider the results of ITU-R studies regarding
sharing between the mobile-satellite service and the space research
service (passive) in the band 1 668 - 1 668.4 MHz, and between the
mobile-satellite service and the mobile service in the band 1 668.4 -
1 675 MHz in accordance with Resolution **744 (WRC‑03)**;

**Background Information**: **(Issue A)** The band 1 668-1 668.4 MHz is
allocated to the space research (passive) service (SRS (passive)) and
the mobile-satellite service (MSS) (Earth-to-space). The space research
allocation may be used by space-based radio astronomy applications, as
part of Space Very Long Baseline Interferometry systems (S-VLBI). The
band 1 668-1 668.4 MHz is a part of the band, 1 660.5-1 668.4 MHz,
allocated to the SRS (passive). However S-VLBI spaceborne receivers
typically receive over a wider frequency band because a wider band is
desirable for increasing the sensitivity of systems and also to observe
highly red-shifted objects.

The potential for interference from mobile earth stations (MES)
operating in the MSS to the S-VLBI systems has been studied by the
ITU-R, in accordance with Resolution **744**. The studies concluded that
to ensure protection of future SRS (passive) systems operating in highly
elliptical orbits, with an apogee of 150 000 km and higher, the power
density of MESs operating in the GSO MSS networks should not exceed to
-- 12.5 dBW/4 kHz in any part of the frequency band 1 668-1 668.4 MHz.

**(Issue B)** The band 1 668.4-1 675 MHz is allocated to the MSS in the
Earth-to-space direction. There are two potential interference
scenarios: 1) interference from transmitting stations in the mobile
service to receiving space stations in the mobile satellite service; and
2) interference from transmitting mobile earth stations to receiving
mobile stations. Regulatory provisions relating to scenario 2 were dealt
with at WRC-03 by the inclusion of a coordination mechanism and
appropriate parameters in Appendix **7** of the Radio Regulations.
However, there are currently no regulatory provisions which address
potential interference from systems in the mobile service to MSS systems
in the band 1 668.4-1 675 MHz. Therefore, the ITU sharing studies have
been focused on scenario 1. No proposals are included herein concerning
this issue.

**Proposal**:

**USA/ /1 ADD**

**5.379\[F\]** In order to protect the space research service (passive)
in the band 1 668-1 668.4 MHz the maximum emission power density of any
mobile earth station in a mobile-satellite service network in the
geostationary satellite orbit network operating in this band, shall not
exceed -12.5 dBW/4 kHz in any part of the frequency band 1 668-1 668.4
MHz.

**Reasons**: To ensure the protection of and future S-VLBI systems
operating in the SRS (passive).

**USA/ /2 MOD**

**5.379D** For sharing of the band 1 668-1 675 MHz between the
mobile-satellite service and the fixed, [and]{.underline} mobile ~~and
space research (passive)~~ services, Resolution **744 (WRC‑03)** shall
apply.     (WRC-03)

**Reasons**: Studies under Res. **744** have concluded with regard to
the SRS (passive).

USA/ /3 MOD

RESOLUTION 744 (WRC-~~03~~[07]{.underline})

Sharing between the mobile-satellite service (Earth-to-space) ~~and the
space research (passive) service in the band 1 668-1 668.4 MHz~~ and
between ~~and the space\
research (passive) service in the band 1 668-1 668.4 MHz and between~~\
the mobile-satellite service (Earth-to-space) and the fixed and\
mobile services in the band 1 668.4-1 675 MHz

The World Radiocommunication Conference (Geneva,
200[7]{.underline}~~2003~~),

Considering

a\) that [WRC-03]{.underline} ~~this conference~~ made a global
allocation to the mobile-satellite service (MSS) (Earth-to-space) in the
band 1 668-1 675 MHz and a global allocation to the MSS (space-to-Earth)
in the band 1 518-1 525 MHz;

b\) that due to sharing conditions between MSS (space-to-Earth) and the
aeronautical mobile service for telemetry in the band 1 518-1 525 MHz
(see No. **5.348B**), MSS operation in the United States of America is
unlikely to be feasible;

c\) that the above constraints on the MSS in the band 1 518-1 525 MHz
therefore limit the possible use of the band 1 668-1 675 MHz by the MSS
in the United States of America;

d\) that the band 1 660.5-1 668.4 MHz is allocated to the space research
(passive) service;

~~e) that in the band 1 668-1 68.4 MHz, mobile earth stations and space
research (passive) stations are subject to coordination under
**No.9.11A**;~~

~~[f]{.underline}~~e) that the band 1 670-1 675 MHz is currently planned
for use in the United States of America for the fixed and mobile
services,

considering further

a\) that the band 1 668.4-1 675 MHz is allocated to the fixed and mobile
services;

b\) that No. **5.380** identifies the band 1 670-1 675 MHz for
aeronautical public correspondence systems but that no such systems
exist;

resolves

that, in the band 1 670-1 675 MHz, stations in the MSS shall not claim
protection from fixed and mobile stations operating within the United
States of America,

**Reasons**: Studies called for in this resolution have been completed.