**United States of America**

## DRAFT PROPOSAL FOR THE WORK OF THE CONFERENCE

**WRC-03 Agenda Item 1.33**: to review and revise technical, operational
and regulatory provisions, including provisional limits in relation to
the operation of high altitude platform stations within IMT‑2000 in the
bands referred to in No. **5.388A**, in response to Resolution **221
(WRC‑2000)**;

**Background Information:** Provisions for operation of high altitude
platform stations (HAPS) were originally made at WRC-97 for HAPS
providing fixed service (FS) operations in the 47.2--47.5 GHz and
47.9--48.2 GHz bands (**5.552A**). A definition of HAPS was also added
to **1.66A**. The use of HAPS as base stations to provide terrestrial
IMT-2000 was approved at WRC-2000, resulting in provisions to facilitate
this being added to the Radio Regulations (**5.388A**). In accordance
with No. **5.388A**, HAPS may be used as base stations within the
terrestrial component of IMT-2000 in the bands 1** **885-1** **980 MHz,
2** **010-2** **025 MHz and 2** **110-2** **170 MHz in Regions 1 and 3
and 1** **885-1** **980 MHz and 2** **110-2** **160 MHz in Region 2; the
use by IMT-2000 applications using HAPS as base stations does not
preclude the use of these bands by any station in the services to which
they are allocated and does not establish priority in the Radio
Regulations.

Resolution **221** from WRC-2000 includes provisional co-channel and
out-of-band power-flux density limits for HAPS operation, for the
protection of other stations either sharing the same band or operating
in adjacent bands and asked for additional technical, operational and
regulatory studies to be conducted, in order to review and, if
necessary, revised, these limits. Resolution **221** also asks for
consideration of appropriate regulatory and technical provisions to
allow bilateral co-ordination of HAPS in an IMT-2000 system with
affected neighbouring administrations.

Based on updated information on typical noise figure of IMT-2000 mobile
stations, WP-8F updated the protection requirement of other IMT-2000
stations operating co-frequency has been revised to - 117 dB
(W/(m^2^MHz)). This PFD threshold is appropriate to protect other
IMT-2000 mobile stations from co-channel interference.

In order to adequately protect MMDS within IMT-2000 in some neighbouring
countries in Region 2 in the band 2 150-2 160 MHz from co-channel
interference, a HAPS operating as a base station to provide IMT-2000
shall not exceed the following co-channel pfd at the Earth's surface
outside an administration's borders unless agreed otherwise by the
administration of the affected neighbouring country:

> -- 127 dB(W/(m^2^MHz))for angles of arrival () less than 7° above the
> horizontal plane;
>
> -- 127**+** 0.666 ( -- 7) dB(W/(m^2^MHz))for angles of arrival between
> 7° and 22° above the horizontal plane; and
>
> -- 117 dB(W/(m^2^MHz)) for angles of arrival between 22° and 90° above
> the horizontal plane.

It is to be noted that the above is an issue concerning the protection
from co-channel interference of certain stations in some neighbouring
countries in Region 2 only.

**Proposal**:

**USA/ /1 MOD**

**RESOLUTION 221 (WRC-20~~00~~[03]{.underline})**

Use of high altitude platform stations as base stations providing
IMT-2000 in the bands 1 885-1 980 MHz, 2 010-2 025 MHz and 2 110-2 170
MHz in Regions 1 and 3 and 1 885-1 980 MHz and 2 110-2 160 MHz in Region
2

The World Radiocommunication Conference ~~(Istanbul, 2000),~~[(Geneva,
2003),]{.underline}

considering

*a)* that the bands 1 885-2 025 MHz and 2 110-2 200 MHz are identified
in No. **5.388** as intended for use on a worldwide basis for
International Mobile Telecommunications-2000 (IMT‑2000), including the
bands 1 980-2 010 MHz and 2 170-2 200 MHz for [both the terrestrial
and]{.underline} the satellite component of IMT-2000;

*b)* that a high altitude platform station (HAPS) is defined in No.
**1.66A** as "a station located on an object at an altitude of 20 to 50
km and at a specified, nominal, fixed point relative to the Earth";

*c)* that HAPS may offer a new means of providing IMT-2000 services with
minimal network infrastructure as they are capable of providing service
to a large footprint together with a dense coverage;

*d)* that the use of HAPS as base stations within the terrestrial
component of IMT-2000 is optional for administrations, and that such use
should not have any priority over other terrestrial IMT-2000 use;

*e)* that in accordance with No. **5.388** and Resolution **212
(Rev.WRC-97**), administrations may use the bands identified for
IMT-2000, including the bands referred to in this Resolution, for
stations of other primary services to which they are allocated;

*f)* that these bands are allocated to the fixed and mobile services on
a co-primary basis;

~~*g)* that ITU-R has studied sharing and coordination between HAPS and
other stations within IMT-2000, has considered compatibility of HAPS
within IMT‑2000 with some services having allocations in the adjacent
bands, and has established Recommendation ITU-R M.1456;~~

~~*h)* that ITU-R did not address sharing and coordination between HAPS
and some existing systems, particularly PCS (personal communications
service), MMDS (multichannel multipoint distribution system) and systems
in the fixed service, which are currently operating in some countries in
the bands 1 885-2 025 MHz and 2** **110-2** **200 MHz;~~

*~~i)~~[g)]{.underline}* that in accordance with No. **5.388A**, HAPS
may be used as base stations within the terrestrial component of
IMT-2000 in the bands 1** **885-1** **980 MHz, 2** **010-2** **025 MHz
and 2** **110-2** **170 MHz in Regions 1 and 3 and 1** **885-1** **980
MHz and 2** **110-2** **160 MHz in Region 2; the use by IMT‑2000
applications using HAPS as base stations does not preclude the use of
these bands by any station in the services to which they are allocated
and does not establish priority in the Radio Regulations,

~~recognizing~~

~~that the values in *resolves* 1 may not be appropriate for the
protection of some stations operating in these bands in the fixed and
mobile services,~~

*h)* [that ITU-R has studied sharing and coordination between HAPS and
other stations within IMT-2000, has considered compatibility of HAPS
within IMT-2000 with some services having allocations in the adjacent
bands, and has established Recommendation ITU-R M.1456;]{.underline}

[*i)* that ITU-R has addressed sharing and coordination between HAPS and
some existing systems, particularly PCS (personal communications
service), MMDS (multichannel multipoint distribution service) and
systems in the fixed service, which are currently operating in some
countries in the bands 1 885-2 025 MHz and 2 110-2 200 MHz;]{.underline}

[*j)* that HAPS stations are intended to transmit in the band 2 110-2
170 MHz in Regions 1 and 3 and in the band 2110-2160 MHz in Region
2]{.underline}

> resolves

**1** that:

**1.1** for the purpose of protecting~~certain~~ [IMT-2000
mobile]{.underline} stations operating~~within IMT-2000~~ in
neighbouring countries from co-channel interference, a HAPS operating as
a base station to provide IMT-2000 shall not exceed a ~~provisional~~
[threshold of]{.underline} co-channel power-flux density (pfd) of
~~\_121.5 dB(W/(m2 · MHz))~~[--117 dB (W/(m^2^ ∙ MHz))]{.underline} at
the Earth's surface outside an administration's borders unless agreed
otherwise by the [consulted]{.underline} administration of the affected
neighbouring country;

~~1.2 a HAPS operating as a base station to provide IMT-2000, in order
to protect fixed stations from interference, shall not exceed the
following provisional values of out‑of‑band pfd at the Earth's surface
in the bands 2 025-2 110 MHz:~~

[1.2 for the purpose of protecting MMDS stations in some neighbouring
countries in Region 2 in the band 2 150-2 160 MHz from co-channel
interference, a HAPS operating as a base station to provide IMT‑2000
shall not exceed the following co-channel power-flux density (pfd)
threshold at the Earth's surface outside an administration's borders
unless agreed otherwise by the consulted administration of the affected
neighbouring country:]{.underline}

~~-- --165 dB(W/(m2 · MHz))~~ [--127 dB(W/(m^2^ ∙MHz))]{.underline} for
angles of arrival () less than ~~5°~~[7°]{.underline} above the
horizontal plane;

[--127 **+** 0.666 ( -- 7) dB(W/(m^2^ ∙ MHz)) for angles of arrival
between 7° and 22° above the horizontal plane; and]{.underline}

[--117 dB(W/(m^2^ ∙ MHz)) for angles of arrival between 22° and 90°
above the horizontal plane;]{.underline}

~~-- --165  1.75 (θ -- 5) dB(W/(m2 · MHz)) for angles of arrival
between 5° and 25° above the horizontal plane; and~~

~~-- --130 dB(W/(m2 · MHz)) for angles of arrival between 25° and 90°
above the horizontal plane;~~

[1.3 a HAPS operating as a base station to provide IMT-2000, in order to
protect fixed stations from interference, shall not exceed the following
limits of out-of-band power-flux density (pfd) at the Earth's surface in
the bands 2 025-2 110 MHz:]{.underline}

[--165 dB(W/(m^2^ ∙ MHz))for angles of arrival () less than 5 the
horizontal plane;]{.underline}

[--165 **+** 1.75 (-- 5) dB(W/(m^2^ ∙ MHz)) for angles of arrival
between 5 and 25 above the horizontal plane; and]{.underline}

[--130 dB(W/(m^2^ ∙ MHz)) for angles of arrival between 25 and 90 above
the horizontal plane;]{.underline}

~~2 that, as of the end of WRC-03, such a HAPS shall operate only in
accordance with such limits as are confirmed or, if appropriate, revised
by WRC-03, irrespective of its date of bringing into use;~~

[2 that, as of the end of WRC-03, such a HAPS shall operate only in
accordance with such power-flux density (pfd) values as are
confirmed]{.underline} [by WRC-03, irrespective of its date of bringing
into use;]{.underline}

[3 that the consultation with neighboring administrations, as mentioned
in *Resolves* 1, be conducted taking into account ITU-R
Rec.\[(HAPS_CON)\] under development;]{.underline}

~~4 that administrations wishing to implement HAPS within a terrestrial
IMT-2000 system shall, prior to their bringing into use, take into
account in their bilateral coordination with affected neighbouring
administrations the operation and growth of existing and planned systems
in the fixed and mobile services having allocations on a primary
basis;~~

~~3~~[4]{.underline} that administrations wishing to implement HAPS
within a terrestrial IMT-2000 system shall comply with the following:

~~3~~[4]{.underline}.1 for the purpose of protecting certain stations
operating within IMT-2000 in neighbouring countries from co-channel
interference, administrations using HAPS as base stations within
IMT‑2000 shall use antennas that comply with the following antenna
pattern:

*G*(ψ) = *Gm* -- 3(ψ/ψ*b*)^2^ dBi for 0° ≤ ψ ≤ ψ1

*G*(ψ) = *Gm*  *LN* dBi for ψ1 \< ψ ≤ ψ2

*G*(ψ) = *X* -- 60 log (ψ) dBi for ψ2 \< ψ ≤ ψ3

*G*(ψ) = *LF* dBi for ψ3 \< ψ ≤ 90°

where:

*G*(ψ)  : gain at the angle ψ from the main beam direction (dBi)

*Gm*  : maximum gain in the main lobe (dBi)

ψ*b*  : one-half of the 3 dB beamwidth in the plane considered (3 dB
below *Gm*) (degrees)

*LN*  : near side-lobe level in dB relative to the peak gain required by
the system design, and has a maximum value of --25 dB

*LF*  : far side-lobe level, *Gm* -- 73 dBi

ψ1 = ψ*b* $\sqrt{\frac{- L_{N}}{3}}$ degrees

ψ2 = 3.745 ψ*b* degrees

*X* = *Gm*  *LN* + 60 log (ψ2) dBi

ψ3 $= \ \text{10}^{(X - L_{F}\frac{)}{\text{60}}}$ degrees

The 3 dB beamwidth (2ψ*b*) is again estimated by:

(ψ*b*)2 = 7 442/(100.1*G~m~*) degrees2

where *Gm* is the peak aperture gain (dBi);

~~3~~[4]{.underline}.2 for the purpose of protecting mobile earth
stations within the satellite component of IMT-2000 from interference, a
HAPS operating as a base station to provide IMT-2000, shall not exceed
an out-of-band pfd of --165 dB(W/(m2 ·  4 kHz)) at the Earth's surface
in the bands 2** **160-2** **200 MHz in Region 2 and 2** **170-2** **200
MHz in Regions 1 and 3;

~~4~~[5]{.underline} that administrations wishing to implement HAPS
within a terrestrial IMT-2000 system shall, prior to their bringing into
use, take into account in their bilateral coordination with affected
neighbouring administrations the operation and growth of existing and
planned systems in the fixed and mobile services having allocations on a
primary basis;

~~5~~[6]{.underline} that, for the purpose of protecting fixed service
stations operating in neighbouring countries from co-channel
interference, administrations wishing to implement HAPS within a
terrestrial IMT-2000 system shall~~, pending the review by WRC-03 of the
studies mentioned below,~~ take full account of the relevant ITU-R
Recommendations relating to protection values for fixed stations (see
Recommendation ITU-R F.758),

~~invites ITU-R~~

~~1 to complete, as a matter of urgency, additional regulatory,
operational and technical studies on sharing criteria for HAPS with
other systems in the bands 1** **885-1** **980 MHz,
2** **010-2** **025 MHz and 2** **110-2** **170 MHz in Regions 1 and 3
and 1** **885-1** **980 MHz and 2** **110-2** **160 MHz in Region 2, and
in adjacent bands, so as to allow revision of the values in *resolves*
1;~~

~~2 to develop appropriate regulatory and technical provisions to allow
the coordination mentioned in *resolves* 4;~~

~~3 to report on the results of these studies in time for consideration
by WRC‑03.~~

**Reasons**: The ITU-R has addressed sharing and coordination between
HAPS and existing systems, particularly IMT-2000 stations operating in
adjacent countries and MMDS (multichannel multipoint distribution
service), which are currently operating in the bands 1 885-2 025 MHz and
2 110-2 200 MHz. The resolution is being modified to reflect the
conclusions of the studies and the PFD thresholds required updating.
Some of the proposed "block" edits to Resolution **221** are merely to
re-organize the text into a more logical manner.