Ms. Helen Domenici

Chief of the International Bureau

Federal Communications Commission

445 12th Street SW

Washington, D.C. 20554

Dear Ms. Domenici:

The National Telecommunications and Information Administration (NTIA),
on behalf of the Executive Branch Agencies, approved the release of an
additional draft Executive Branch preliminary view for 2011 World
Radiocommunication Conference (WRC-11). This draft preliminary view
considers the Federal agency inputs toward the development of U.S.
Proposals for WRC-11.

The enclosure contains a draft preliminary view that addresses the
second part of WRC-11 Agenda Item 1.6 which is concerned with Resolution
955. This preliminary view is forwarded for your consideration and
review by your WRC-11 Advisory Committee. Darlene Drazenovich of my
staff is the primary contact for NTIA.

> Sincerely,
>
> *(Original Signed November 25, 2008)*
>
> Karl B. Nebbia
>
> Associate Administrator
>
> Office of Spectrum Management

Enclosure

***Radio Conference Subcommittee (RCS)***

Preparation for ITU World Radiocommunication Conferences

**UNITED STATES OF AMERICA**

**DRAFT PRELIMINARY VIEWS ON WRC-11**

**AGENDA ITEM 1.6 (Res. 955)**: 1.6 to review No. **5.565** of the Radio
Regulations in order to update the spectrum use by the passive services
between 275 GHz and 3 000 GHz, in accordance with Resolution **950
(Rev.WRC-07)**, and to consider possible procedures for free-space
optical-links, taking into account the results of ITU-R studies, in
accordance with Resolution **955 (WRC-07)**;[^1]

**ISSUES**: The primary issue is whether procedures are necessary for
free-space optical links above 3 000 GHz.

**BACKGROUND**: Resolution **955 (WRC-07)** considers possible
procedures for free-space optical links. Because the atmosphere is
essentially opaque at frequencies between 3 000 GHz and the
near-infrared range, terrestrial free-space optical links operate at
frequencies in or above the near-infrared range. Although
inter-satellite links do not suffer from absorption, such links also
generally use frequencies in the near-infrared range, due to the ready
availability of transceiver (laser) technology in that range.

No. 1005 of the Annex to the ITU Convention indicates that the term
"radiocommunication" is limited to "electromagnetic waves of frequencies
arbitrarily lower than 3 000 GHz,"[^2] except in the context of
radiocommunication study groups addressing study questions and WRC
resolutions and recommendations. However, the 2002 Plenipotentiary
Conference adopted Resolution **118** (Marrakesh), which resolves that
"world radiocommunication conferences can include in agendas for future
conferences, items relevant to spectrum regulation of frequencies above
3 000 GHz and take any appropriate measures, including revision of the
relevant parts of the Radio Regulations." The outcome of this agenda
item might be impacted by the outcome of the 2010 Plenipotentiary
Conference should the upper limit of 3 000 GHz remain in the definitions
in No. 1005.

Because emitters used in near-infrared, free-space links have extremely
narrow beamwidth, and terrestrial emitters can only cause interference
over very short distances, cases of terrestrial interference will be
very rare and easily resolved on a local basis. Moreover, interference
between inter-satellite links would also be rare due to directed and
narrow beamwidths, and the vast geometry of space.

**U.S. VIEW**: The United States believes that international regulations
are not needed for frequencies above 3 000 GHz. Therefore, the
development of procedures for free-space optical links is not necessary.

[^1]: This preliminary view only addresses the second part of the agenda
    item (free-space optical links), hereafter referred to as Agenda
    Item 1.6 (Res. 955). The first part of the agenda item (275 -- 3 000
    GHz), referred to as Agenda Item 1.6 (Res. 950), is addressed in a
    separate document.

[^2]: In the French text, the frequency limit is "by convention". In the
    Spanish text it is termed "conventionally", and in the English text
    it is termed "arbitrarily".