Mr. Roderick K. Porter

Chief of the International Bureau

Federal Communications Commission

Washington, D.C. 20554

Dear Mr. Porter:

The National Telecommunications and Information Administration on behalf
of the Executive Branch Agencies, has approved the release of five
additional proposals for WRC-2000. These proposals are being forwarded
to your WRC-2000 Advisory Committee for review. Karl Nebbia from my
staff will contact Damon Ladson and reconcile any differences. The
following is a summary of our proposals:

> **WRC-2000 Agenda Item 1.3 -** Appendix **S7** provides the methods
> for determining the coordination area around earth stations. These
> methods have not been updated in the Radio Regulations since 1979. We
> are proposing that the current text of this appendix be suppressed. It
> will be replaced with "incorporation-by-reference"; furthermore, the
> references in Appendix **S5** TABLE **S5-1**, and Appendix **S5**
> Annex 1 TABLES 2, 3 and 4 will be updated.
>
> **WRC-2000 Agenda Item 1.4 -** WRC-97 added a primary allocation to
> the fixed service in the frequency band 31.8 - 33.4 GHz. Footnote
> S5.547A sets forth that the use of this band by the fixed service
> shall be in accordance with Resolution **126 (WRC-97)**, and footnote
> **S5.547** makes this band (among others) available for high-density
> applications in the fixed service per Resolution **726 (WRC-97)**. The
> criteria being considered for sharing are onerous and contrary to the
> operational requirements of the radionavigation service. No allowance
> is being made for the future requirements and development of the
> radionavigation service per *resolves* 2 of Resolution **126
> (WRC-97)**. For these reasons, we propose the removal of the
> provisional allocation of the band 31.8 -- 33.4 GHz to the fixed
> service and high-density applications there.
>
> **WRC-2000 Agenda Item 1.6.2** - This proposal addresses IMT-2000 and
> proposes that a radio control channel is not needed for this system.
>
> **WRC-2000 Agenda Item 1.7** - This proposal addresses High Frequency
> (HF) distress and safety communications for the aeronautical mobile
> (R) services which have been subjected to harmful interference. This
> proposal addresses ways to decrease this interference.
>
> **WRC-2000 Agenda Item 1.18 -** WP8B and the CPM recommend
> modifications to Appendix **S18** to provide administrations with
> further flexibility to use the channels of Appendix **S18** in simplex
> mode if required. Our proposal would modify Note M to allow simplex
> use of duplex channels for the remainder of the channels not already
> identified as simplex.
>
> Sincerely,
>
> William T. Hatch
>
> Acting Associate Administrator
>
> Office of Spectrum Management

Enclosures

**United States of America**

**(Draft) Proposals for the Work of the Conference**

# Proposals for Agenda Item 1.3

## to consider the results of ITU-R studies in respect of Appendix S7/28 on the method for the determination of the coordination area around an earth station in frequency bands shared among space services and terrestrial radiocommunication services, and to take the appropriate decision to revise this Appendix

**Background Information:** Appendix **S7** provides the methods for
determining the coordination area around earth stations. These methods
have not been updated in the Radio Regulations since 1979. Since that
time system characteristics have changed, new bands have been allocated
to satellite services, and propagation tools have been improved.

ITU-R Recommendation **IS. XX** consolidates the text of ITU-R
Recommendations **847** through **849**, uses updated system
characteristics, extends the frequency range, and separates the
propagation aspects from other probability aspects. Therefore, it serves
as a useful basis for updating Appendix **S7**.

**Proposal**[^1]**:**

Recognizing that the frequency bands covered by the methods for
determining coordination areas, the system technical characteristics,
and the potential operating scenarios will change with the decisions at
each WRC, the United States proposes incorporating ITU-R Recommendation
**IS. XX** into the Radio Regulations by reference. Even if Appendix
**S7** is updated based on ITU-R Recommendation **IS. XX**, it will
probably be out-of-date at the close of WRC-2000 based on decisions made
at the conference. It will remain so for years to come unless the
recommendation is referenced to facilitate future updates. If the
incorporation-by-reference method is not used, future updates will
require a specific agenda item to be agreed. Given that it has required
twenty years to update the current appendix and noting the rapid
evolution of satellite and terrestrial radio communications, another
long delay in updating the text would not be acceptable.

This proposed modification to Appendix **S7** involves the suppression
of the entire text of the Appendix and its replacement with the
"incorporation-by-reference" text as shown below. Furthermore, it
includes updated references in Appendix **S5** TABLE **S5-1**, and
Appendix **S5** Annex 1 TABLES 2, 3 and 4.

~~APPENDIX S7~~

~~Method for the Determination of the Coordination Area Around an\
Earth Station in Frequency Bands Between 1 GHz and 40 GHz Shared\
Between Space and Terrestrial Radiocommunication Services~~

**Reasons:** All text in the current Appendix **S7** should be
suppressed.

APPENDIX **S7**

# Method for the Determination of the Coordination Area Around an Earth Station in Frequency Bands Between 1 GHz and 40 GHz Shared Between Space and Terrestrial Radiocommunication Services

# The method for determining the coordination area around an earth station between the frequency bands between .1 GHz and 105 GHz shared between space and terrestrial radiocommunications services is given in Annexes 1 through 3 of ITU-R Recommendation IS. XX.

**Reason:** To update the method for determining coordination areas and
to provide a responsive mechanism for future updates.

APPENDIX **S5**

Identification of administrations with which coordination is to be
effected or agreement sought under the provisions of Article S9

TABLE S5-1

Technical conditions for coordination\
(see Article S9)

+------+-------------+------------+----------+----------+-----------+
| Re   | Case        | Frequency  | Thr      | Calc     | Remarks   |
| fere |             | bands\     | eshold/c | ulation\ |           |
| nce\ |             | (and       | ondition | method   |           |
| of   |             | Region) of |          |          |           |
| Art  |             | the        |          |          |           |
| icle |             | service\   |          |          |           |
| S9   |             | for which  |          |          |           |
|      |             | coo        |          |          |           |
|      |             | rdination\ |          |          |           |
|      |             | is sought  |          |          |           |
+------+-------------+------------+----------+----------+-----------+
| No.  | A specific  | Any        | The      | i\) For  |           |
| **S  | earth       | frequency  | coor     | bands    |           |
| 9.17 | station in  | band       | dination | in\      |           |
| A**\ | respect of  | allocated  | area of  | Tabl     |           |
| GSO, | other earth | to a space | the      | e S5-2,\ |           |
| non‑ | stations    | service    | earth    | see § 2  |           |
| GSO/ | operating   |            | station  | of Annex |           |
| GSO, | in the      |            | covers   | 1\       |           |
| non  | opposite    |            | the t    | of this  |           |
| ‑GSO | direction   |            | erritory | Appendix |           |
|      | of          |            | of       |          |           |
|      | t           |            | another  | ii\) See |           |
|      | ransmission |            | admini   | Recomm   |           |
|      | in          |            | stration | endation |           |
|      | frequency   |            | or the   | ITU-R    |           |
|      | bands       |            | earth    | IS.XX    |           |
|      | allocated   |            | station  |          |           |
|      | with equal  |            | is       |          |           |
|      | rights to   |            | located  |          |           |
|      | space       |            | within   |          |           |
|      | radioco     |            | the      |          |           |
|      | m­munication |            | coor     |          |           |
|      | services in |            | dination |          |           |
|      | both        |            | area of  |          |           |
|      | directions  |            | an earth |          |           |
|      | of          |            | station  |          |           |
|      | tr          |            |          |          |           |
|      | ansmission, |            |          |          |           |
|      | where the   |            |          |          |           |
|      | c           |            |          |          |           |
|      | oordination |            |          |          |           |
|      | area of the |            |          |          |           |
|      | earth       |            |          |          |           |
|      | station     |            |          |          |           |
|      | includes    |            |          |          |           |
|      | the         |            |          |          |           |
|      | territory   |            |          |          |           |
|      | of another  |            |          |          |           |
|      | country or  |            |          |          |           |
|      | the earth   |            |          |          |           |
|      | station is  |            |          |          |           |
|      | located     |            |          |          |           |
|      | within the  |            |          |          |           |
|      | c           |            |          |          |           |
|      | oordination |            |          |          |           |
|      | area of a   |            |          |          |           |
|      | coordinated |            |          |          |           |
|      | earth       |            |          |          |           |
|      | station,    |            |          |          |           |
|      | with the    |            |          |          |           |
|      | exception   |            |          |          |           |
|      | of the      |            |          |          |           |
|      | frequency   |            |          |          |           |
|      | bands       |            |          |          |           |
|      | subject to  |            |          |          |           |
|      | the Plans   |            |          |          |           |
|      | in Appendix |            |          |          |           |
|      | **S30A**    |            |          |          |           |
+------+-------------+------------+----------+----------+-----------+

## Reason: Update references to recommendations dealing with determination of coordination areas.

## Appendix S5

Annex 1

TABLE 2

Earth stations operating at frequencies in the 1-3 GHz range

  -------------------------- ------------------- -------------- ----------------------------------
  Frequency sharing                              Coordination   
  situation                                      distance       

  Frequency band and earth   Other service\                     (in sharing situations involving
  station for which          or station (station                services\
  coordination area is       in terrestrial                     allocated with equal rights)(km)
  determined                 service\                           
                             or earth station)                  

  Ground-based mobile (NOTE  Ground-based                       Determined using Recommendation
  1)\                        stations in                        ITU-R **IS.XX ~~847~~** with the
  (GSO network)              terrestrial                        parameters specified therein for
                             services                           terrestrial stations and all
                                                                applicable equations and figures

  Ground-based mobile\       Ground-based                       The methodology of Recommendation
  (NOTE 1)\                  stations in                        ITU-R **IS.XX ~~849~~** is applied
  (non-GSO network)          terrestrial                        ~~in conjuncition with
                             services                           Recommendation ITU-R **IS.847**
                                                                (see above)~~

  NOTE 1 -- Recommendation                                      
  ITU-R **IS.XX** supplies                                      
  the necessary terrestrial                                     
  station parameters for the                                    
  bands 1 492-1 530 MHz,                                        
  1 555-1 559 MHz,                                              
  1 610-1 645.5 MHz,                                            
  1 646.5-1 660 MHz,                                            
  1 675-1 710 MHz,                                              
  1 980-2 025 MHz,                                              
  2 160-2 200 MHz,                                              
  2 483.5-2 520 MHz, and                                        
  2 655-2 690 MHz.                                              
  -------------------------- ------------------- -------------- ----------------------------------

**Reason:** Update references to recommendations dealing with
determination of coordination areas.

TABLE 3

Non-GSO MSS feeder-link earth stations

  ------------------ -------------------- -----------------------------------
  Frequency sharing                       Coordination distance
  situation                               

  Frequency band and Other service\       (in sharing situations involving
  earth station for  or station (station  services\
  which coordination in terrestrial       allocated with equal rights)
  area is determined service\             
                     or earth station)    

  19.3-19.7 GHz and\ Ground-based         Determined using Recommendations
  29.1-29.5 GHz;     stations in          ITU-R **IS.XX** ~~**847** and ITU-R
  earth station      terrestrial services **IS.849**~~ with the parameters
  operating\                              specified therein for terrestrial
  co-directionally                        stations and all applicable
  with other earth                        equations and figures.
  stations                                
  ------------------ -------------------- -----------------------------------

**Reason:** Update references to recommendations dealing with
determination of coordination areas.

TABLE 4

Non-GSO FSS earth stations

+--------------------+----------------+--------------------------------+
| Frequency sharing  |                | **Coordination distance**      |
| situation          |                |                                |
|                    |                | **(in sharing situations       |
|                    |                | involving services allocated   |
|                    |                | with equal rights)**           |
+--------------------+----------------+--------------------------------+
| Frequency band and | Other service  |                                |
| earth station for  | or station     |                                |
| which coordination | (station in    |                                |
| area is determined | terrestrial    |                                |
|                    | service or     |                                |
|                    | earth station) |                                |
+--------------------+----------------+--------------------------------+
| 18.9-19.3 GHz and  | Ground-based   | Determined using               |
| 28.7-29.1 GHz;     | stations in    | Recommendations ITU-R          |
| earth station      | terrestrial    | **IS.XX** ~~**847** and ITU-R  |
| operating          | services       | **IS.849**~~ with the          |
| co-directionally   |                | parameters specified therein   |
| with other earth   |                | for terrestrial stations and   |
| stations           |                | all applicable equations and   |
|                    |                | figures.                       |
+--------------------+----------------+--------------------------------+

**Reason:** Update references to recommendations dealing with
determination of coordination areas.

United States of America

**\[DRAFT\] PROPOSALS FOR THE WORK OF THE CONFERENCE**

# Proposals for Agenda Item 1.4[^2]

## to consider issues concerning allocations and regulatory aspects related to Resolutions 126 (WRC-97), 128 (WRC-97), 129 (WRC-97), 133 (WRC-97), 134 (WRC-97), and 726 (WRC-97)

# Background Information: WRC-97 added a primary allocation to the fixed service in the frequency band 31.8 - 33.4 GHz. Footnote S5.547A sets forth that the use of this band by the fixed service shall be in accordance with Resolution 126 (WRC-97), and Footnote S5.547 makes this band (among others) available for high-density applications in the fixed service per Resolution 726 (WRC-97).

Taken together, Resolutions **126 (WRC-97)** and **726 (WRC-97)**
*resolve* that;

-   the date of application of the fixed service and high-density
    applications therein is 1 January 2001, and,

-   that WRC-2000 should review this allocation, including the date of
    application, taking full account of the future requirements and
    development of the other services to which the band is allocated and
    available ITU-R studies.

The radionavigation service is one of the incumbent primary services in
the frequency band 31.8 -- 33.4 GHz. ITU-R WP 9D, per the *requests* of
Resolution **126 (WRC-97)**, has been studying the criteria necessary
for sharing between stations in the fixed service and stations in the
other services to which the frequency band 31.8 -- 33.4 GHz is
allocated. Study results indicate that there is a significant potential
for interference from stations in the radionavigation service into
stations of the fixed service. There is also a potential for degradation
in the performance of the radionavigation service due to the emissions
of the fixed service. This was intuitively obvious, and was the reason
the U.S. opposed this allocation at WRC-97.

Airborne radars \[aboard U.S. C-130 aircraft\] operate on a worldwide
basis in the frequency band 31.8 -- 33.4 GHz. Proponents of the use of
this frequency band for the fixed service are proposing that the
radionavigation service restricts its operations with respect to radar
antenna pointing angles and operational altitudes. They further propose
to assign "priority channels" (a communications term not generally used
with respect to radars) such that certain frequencies within the band
would be designated for use by the radars. This latter proposal is
actually a form of band segmentation (at least on a geographic basis)
and is in conflict with the opinions of both the fixed service and
radionavigation service that band segmentation is not recommended.

The criteria being considered for sharing, as described above, are
onerous and contrary to the operational requirements of the
radionavigation service. Further, no allowance is being made for the
future requirements and development of the radionavigation service per
*resolves* 2 of Resolution **126 (WRC-97)**. For these reasons, the
following proposals are made to remove the provisional allocation of the
band 31.8 -- 33.4 GHz to the fixed service and high-density applications
therein.

**Proposals:**

**Section IV -- Table of Frequency Allocations**

31.8-33.4 GHz

  ----------------------- ----------------------- -----------------------
  Allocation to services                          

  Region 1                Region 2                Region 3
  ----------------------- ----------------------- -----------------------

+-----------------------------------------------------------------------+
| **31.8-32** ~~FIXED S5.547A~~                                         |
|                                                                       |
| RADIONAVIGATION                                                       |
|                                                                       |
| SPACE RESEARCH (deep space) (space-to-Earth)                          |
|                                                                       |
| **MOD** S5.547 ~~S5.547B~~ S5.548                                     |
+-----------------------------------------------------------------------+

+-----------------------------------------------------------------------+
| **32-32.3** ~~FIXED S5.547A~~                                         |
|                                                                       |
| INTER-SATELLITE                                                       |
|                                                                       |
| RADIONAVIGATION                                                       |
|                                                                       |
| SPACE RESEARCH (deep space) (space-to-Earth)                          |
|                                                                       |
| **MOD** S5.547 ~~S5.547C~~ S5.548                                     |
+-----------------------------------------------------------------------+

+-----------------------------------------------------------------------+
| **32.3-33** ~~FIXED S5.547A~~                                         |
|                                                                       |
| INTER-SATELLITE                                                       |
|                                                                       |
| RADIONAVIGATION                                                       |
|                                                                       |
| **MOD** S5.547 ~~S5.547D~~ S5.548                                     |
+-----------------------------------------------------------------------+

+-----------------------------------------------------------------------+
| **33-33.4 ~~FIXED S5.547A~~**                                         |
|                                                                       |
| **RADIONAVIGATION**                                                   |
|                                                                       |
| **MOD S5.547 ~~S5.547E~~**                                            |
+-----------------------------------------------------------------------+

**S5.547** The bands ~~31.8 - 33.4 GHz~~, 51.4 -- 52.6 GHz, 55.78 -- 59
GHz, and 64 -- 66 GHz are available for high-density applications in the
fixed service (see **MOD** Resolution **726 (WRC-97)**).

**S5.547A**

**S5.547B**

**S5.547C**

**S5.547D**

**S5.547E**

**Reasons:** ITU-R studies have shown that unacceptable operational
limitations would be necessary upon the existing radionavigation service
in the band 31.4 -- 33.4 GHz, in order to accommodate fixed service use
of this band. Such operational limitations (such as limitations upon
altitude of use and antenna pointing angles) are contrary to the
inherent requirements of the radionavigation service. Further,
postulated assignment of "priority channels" for use by the
radionavigation service will reduce the bandwidth available for
frequency agile and frequency hopping systems, which is required to meet
system performance requirements in adverse environmental conditions and
increase intra-system interference problems within the radionavigation
service. Finally, sharing with the fixed service will severly impact
future requirements and restrict developments by the radionavigation
service.

~~RESOLUTION 126 (WRC-97)~~

#### ~~USE OF THE FREQUENCY BAND 31.8 -- 33.4 GHz FOR HIGH DENSITY~~

~~SYSTEMS IN THE FIXED SERVICE~~

**Reason:** Consequential to changes made to the allocation table.

**RESOLUTION 726 (WRC-97)**

##### FREQUENCY BANDS ABOVE 30 GHz AVAILABLE FOR HIGH-DENSITY APPLICATIONS IN THE FIXED SERVICE

*Resolves*

that administrations should take into account that the bands ~~31.8 -
33.4 GHz~~, 51.4 - 52.6 GHz, 55.78 -- 59 GHz and 64 -- 66 GHz are
available for high-density applications in the fixed service, when
considering allocations or other regulatory provisions in relation to
these bands,

~~\*The date of provisional application of this allocation shall be in
conformity with Resolution 126.~~

**Reason:** Consequential to the changes made to the allocation table.

**United States of America**

**(Draft) Proposals for the Work of the Conference**

# Proposal for Agenda Item 1.6.2

## Identification of a global radio control channel to facilitate multimode terminal operation and worldwide roaming of IMT-2000

Background Information: At the time that the WRC-2000 agenda was
established, studies were underway within TG8/1 examining whether global
roaming could be accomplished by identifying one or more global radio
control channels that could allow radios to be tuned to the appropriate
frequency band identifying a "physical" channel was wanted, in favor of
using other approaches that may include the development of a "logical"
channel structure for this purpose.

Based on discussions to date within TG8/1, it has been determined that
facilitation of multimode terminal operation and worldwide roaming of
IMT-2000 is possible without a specific physical global radio control
channel.

Proposal:

There is not a need to identify a global radio control channel for
IMT-2000 in the Radio Regulations, therefore no action is required by
WRC-2000.

Reasons: There is no need for a physical radio control channel in order
to facilitate the global roaming of IMT-2000 terminals.

**United States of America**

**(DRAFT) PROPOSALS FOR THE WORK OF THE CONFERENCE**

# Proposal for Agenda Item 1.7

(Part 1 of 2)[^3]

## (Review of the use of the HF bands by the aeronautical mobile (R) and maritime mobile services with a view to protecting operational, distress and safety communications, taking into account Resolution 346 (WRC-97))

**Background Information:** WP8B and the CPM have identified two issues
comprising this agenda item;

1)  High Frequency (HF) bands allocated for the distress and safety
    communications of the maritime and aeronautical mobile (R) services
    have been subjected to an increase in harmful interference caused by
    unauthorized use. It is essential for the safety-of-life and
    property that these distress and safety channels, in particular for
    aeronautical use, are kept free from unauthorized use and harmful
    interference.

2)  Several maritime HF distress and safety frequencies are also used
    for international routine calling. The routine calling causes
    interference to distress and safety communications.

AERONAUTICAL ISSUES

The interference to HF frequencies allocated to the aeronautical mobile
(R) service between 2 850 kHz and 22 000 kHz appears to be the result of
unauthorized non-aviation use of aeronautical mobile (R) frequencies. In
some parts of the world the aeronautical mobile (R) HF frequencies are
being used for land mobile, broadcast, fixed point-to-point
communications and unlicensed applications to support fishing fleets.
These unauthorized applications have diminished the spectrum available
for the aeronautical mobile (R) safety-of-life applications.

Administrations should ensure that stations of services other than the
aeronautical mobile (R) service abstain from using frequencies in the
bands allocated exclusively to the aeronautical mobile (R) service.
Administrations should make every effort to identify and locate the
source of any unauthorized emission capable of endangering human life
and property and the safe and regular conduct of aircraft operations,
and to take necessary measures to prevent stations from operating in
contravention of ITU Radio Regulations.

WP8B and the CPM recommend modifications of Article **S15** to ensure
that suitable provisions are made for the aeronautical mobile (R)
service.

The United States proposes modifications to Article **S15** to include
reference to Appendix **S27**. This modification will ensure special
consideration is given to avoiding interference on the frequencies used
for safety and regularity of flight. Currently, Article **S15** only
refers to Article **S31** Appendix **S13**, which is primarily for
maritime services.

The United States proposes no changes to Appendix **S27**. Presently,
the HF bands allocated to the aeronautical mobile (R) service are nearly
saturated by the use of analog voice communications. This spectrum must
be maintained for the new digital high frequency data link (HFDL)
communications. HFDL communications will provide a capability for the
transfer of air traffic control data to and from pilots operating over
oceanic airspace, on polar routes, and in airspace over sparsely
populated or undeveloped countries where other communications systems
are not practical. The world-wide implementation of HFDL communications
will reduce the burden on voice communications between pilots and
controllers by using the data link for routine communications and
freeing voice communications for more critical communications. HFDL will
not replace voice communications. The International Civil Aviation
Organization (ICAO) will have completed Standards and Recommended
Practices for HFDL before the end of 1999. Appendix **S27** contains the
Allotment Plan for the aeronautical use of HF aeronautical mobile
(Route) service. Review of Appendix **S27**, if necessary, should be
performed by ICAO and by ITU-R Working Party 8B and consequently
considered by the ITU-R for action.

**Proposal:**

ARTICLE S15

Interferences

Section I -- Interference from Radio Stations

**S15.8** § 4 Special consideration shall be given to avoiding
interference on distress and safety frequencies and those related to
distress and safety identified in Appendix** S13** [and safety and
regularity of flight identified in Appendix **S27**,]{.underline}

**Reasons:** Frequencies for safety and regulatory of flight in the
Aeronautical Mobile (R) service are not listed in Appendix **S13**,
since this appendix is primarily for maritime services. Inclusion of
Appendix **S27** in this provision will ensure special consideration is
given to avoiding interference on these frequencies used for safety and
regularity of flight.

Section VI -- Procedure in a case of harmful interference

**S15.28** § 20 Recognizing that transmissions on the distress and
safety frequencies [and frequencies used for the safety and regularity
of flight]{.underline} (See Article **S31[,]{.underline}** ~~and~~
Appendix** S13** [and Appendix **S27**]{.underline}) require absolute
international protection[,]{.underline} and that the elimination of
harmful interference to such transmissions is imperative,
administrations [should]{.underline} ~~undertake to~~ act immediately
when their attention is drawn to any such harmful interference.

**Reasons:** Frequencies for safety and regulatory of flight in the
Aeronautical Mobile (R) service are not listed in Article **S31** or
Appendix **S13**, since this appendix is primarily for maritime
services. Inclusion of Appendix **S27** would lead to the protection of
frequencies used for safety and regularity of flight against
interference.

**S15.35 § 27 On being informed that a station over which it has
jurisdiction is believed to have been the cause of harmful interference,
an administration shall, as soon as possible, acknowledge receipt of
that information by ~~telegram~~ [the quickest means
available]{.underline}. Such acknowledgement shall not constitute an
acceptance of responsibility.**

**Reasons:** Improvements in technology provide quicker means of
communicating information, such email and facsimiles. The quicker a case
of interference is reported, the quicker the action can be taken against
that interference, and the shorter the duration of the interference.

APPENDIX S27

**Frequency allotment Plan for the aeronautical mobile (R) service and
related information**

**Reasons:** ICAO in consultation with the ITU-R should perform any
review of Appendix **S27**, if necessary. The HF bands allocated to the
aeronautical mobile (R) service are nearly saturated by the use of
analog voice communications. This spectrum must be maintained for the
new digital high frequency data link (HFDL) communications. The
world-wide implementation of HFDL communications will reduce the burden
on voice communications between pilots and controllers by using the data
link for routine communications and freeing voice communications for
more critical communications.

**United States of America**

**(DRAFT) PROPOSALS FOR THE WORK OF THE CONFERENCE**

# Proposal for Agenda Item 1.18

## (To consider the use of new digital technology for the maritime mobile service in the band 156-174 MHz and consequential revision of Appendix S18, taking into account Resolution 342 (WRC-97)

**Background Information:** Appendix **S18** of the ITU Radio
Regulations defines the channels of the maritime mobile service. These
channels support a variety of functions including "Distress, Safety and
Calling: public correspondence, inter-ship, ship/shore/ship, port
operations and ship movement. The maritime mobile frequency band,
156-174 MHz, (effectively 156-162 MHz in the United States due to
previous domestic regulatory actions), supports maritime communications
worldwide.

WP8B and the CPM studied this agenda item and determined that the
modification of Appendix **S18** includes the possibility to implement
new applications and the relief of congestion in the band. The status of
the ITU-R studies indicate that revision s of Appendix **S18** to
introduce new digital technologies is not possible at this conference.
However, it is possible to take action to address the issue of
congestion.

With the rapidly increasing use of the VHF maritime mobile band,
particularly for data communications, increased congestion and mutual
interference is being experienced which, among others, has resulted in
unacceptable degradation of the distress and safety related function for
which this band is utilized. Unless action is taken this situation will
only worsen as usage continue to grow.

At WRC-97, the United States and CITEL proposed simplex use of duplex
channels for Appendix **S18**. This was approved for a few specific
public correspondence channels only, channels 18 and 82-86. Note M to
Appendix **S18** must be modified to add more channels for simplex use.
This will allow for more efficient use of Appendix **S18** channels and
provide flexibility for administrations to meet their immediate
requirements, while maintaining compatibility with the vast number of
ships and pleasure craft now using the band in accordance with Appendix
**S18**.

WP8B and the CPM recommend modifications to Appendix **S18** to provide
administrations with further flexibility to use the channels of Appendix
**S18** in simplex mode if required. This would allow the use of duplex
channels in Appendix **S18** in simplex mode and would increase the
number of available channels. The cost of the change would be minimal
and administrations could be able to quickly address certain local
problems of congestion.

The United States proposes to modify Note M to allow simplex use of
duplex channels for the remainder of the channels not already identified
as simplex.

**Proposal:**

APPENDIX **S18**

Table of transmitting frequencies in the VHF\
maritime mobile band

(See Article **S52**)

> NOTE -- For assistance in understanding the Table, see notes *a)* to
> *n)* below.

**Notes referring to the Table**

*Specific notes*

*m)* These channels ~~(18 and 82 to 86)~~ may be operated as single
frequency channels, subject to special arrangement between interested or
affected administrations.

> **Reasons**: Adding more channels for simplex use will allow for more
> efficient use of Appendix **S18** channels and provide flexibility for
> administrations to meet their immediate requirements, while
> maintaining compatibility with the vast number of ships and pleasure
> craft now using the band in accordance with Appendix **S18**.

[^1]: Only the portion of the tables being modified are shown in this
    proposal.

[^2]: ^^ The proposals advanced in this paper may not represent the
    full extent of U.S. proposals to WRC-2000 on Agenda Item 1.4.

[^3]: This proposal will only address item 1 above as it relates to
    aeronautical issues. Another proposal is being developed regarding
    maritime issues.