Information Sought on Sharing the Lower 37 GHz Band in Connection With the National Spectrum Strategy Implementation Plan, 68610-68616 [2024-19081]

Agencies

• FEDERAL COMMUICATIONS COMMISSION

[Federal Register Volume 89, Number 166 (Tuesday, August 27, 2024)]
[Notices]
[Pages 68610-68616]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-19081]


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FEDERAL COMMUICATIONS COMMISSION

[WT Docket No. 24-243; DA 24-789; FR ID 240134]


Information Sought on Sharing the Lower 37 GHz Band in Connection 
With the National Spectrum Strategy Implementation Plan

AGENCY: Federal Communications Commission.

ACTION: Notice of collection; request for comment.

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SUMMARY: In this document, the Federal Communications Commission 
(Commission) seeks to further develop the record for the 37.0-37.6 GHz 
band (Lower 37 GHz band) with the goal of informing the forthcoming 
report mandated by the National Spectrum Strategy (NSS) Implementation 
Plan. The NSS identified the Lower 37 GHz band for in-depth study to 
determine how a co-equal, shared-use framework which allows Federal and 
non-federal operations should be implemented. The comments filed in 
response will be shared with the National Telecommunications and 
Information Administration and the Department of Defense to assist in 
developing the report required by the NSS Implementation Plan.

DATES: Comments may be submitted on or before September 9, 2024.

ADDRESSES: You may submit comments, identified by WT Docket No. 24-243, 
by any of the following methods:
     Electronic Filers: Comments may be filed electronically 
using the internet by accessing the ECFS: https://www.fcc.gov/ecfs/.
     Paper Filers: Parties who choose to file by paper must 
file an original and one copy of each filing.
     Filings can be sent by hand or messenger delivery, by 
commercial courier, or by the U.S. Postal Service. All filings must be 
addressed to the Secretary, Federal Communications Commission.
     Hand-delivered or messenger-delivered paper filings for 
the Commission's Secretary are accepted between 8:00 a.m. and 4:00 p.m. 
by the FCC's mailing contractor at 9050 Junction Drive, Annapolis 
Junction, MD 20701. All hand deliveries must be held together with 
rubber bands or fasteners. Any envelopes and boxes must be disposed of 
before entering the building.
     Commercial courier deliveries (any deliveries not by the 
U.S. Postal Service) must be sent to 9050 Junction Drive, Annapolis 
Junction, MD 20701. Filings sent by U.S. Postal Service First-Class 
Mail, Priority Mail, and Priority Mail Express must be sent to 45 L 
Street NE, Washington, DC 20554.
     People with Disabilities: To request materials in 
accessible formats for people with disabilities (Braille, large print, 
computer diskettes, audio format), send an email to [email protected] or 
call the Consumer & Governmental Affairs Bureau at 202-418-0530 
(voice).

FOR FURTHER INFORMATION CONTACT: Catherine Schroeder, Broadband 
Division, Wireless Telecommunications Bureau, at (202) 418-1956 or 
[email protected].

SUPPLEMENTARY INFORMATION: This is a summary of the Commission's 
document (Public Notice), in WT Docket No. 24-243, DA 24-789, released 
on August 9, 2024. The full text of this document is available at 
https://docs.fcc.gov/public/attachments/DA-24-789A1.pdf.

Information Sought on Sharing the Lower 37 GHz Band in Connection With 
the National Spectrum Strategy Implementation Plan

    With this Public Notice, the Wireless Telecommunications Bureau 
seeks to further develop the record for the 37.0-37.6 GHz band (Lower 
37 GHz band) with the goal of informing the forthcoming report mandated 
by the National Spectrum Strategy (NSS) Implementation Plan. The NSS 
identified the Lower 37 GHz band for in-depth study to determine how a 
co-equal, shared-use framework which allows Federal and non-federal 
operations should be implemented.\1\

[[Page 68611]]

The final report with findings is to be completed by November 2024.\2\
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    \1\ National Telecommunications and Information Administration, 
National Spectrum Strategy at 3, 6-7 (2023), https://www.ntia.gov/sites/default/files/publications/national_spectrum_strategy_final.pdf (NSS). National 
Telecommunications and Information Administration, National Spectrum 
Strategy Implementation Plan at 6 (2024), https://www.ntia.gov/sites/default/files/publications/national-spectrum-strategy-implementation-plan.pdf (NSS Implementation Plan).
    \2\ NSS Implementation Plan at A-12.
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    Background. In 2016, the Commission, in coordination with the 
National Telecommunications and Information Administration (NTIA), made 
the Lower 37 GHz band available for coordinated, co-primary sharing 
between Federal and non-federal fixed and mobile users and determined 
that Federal and non-federal users would access the Lower 37 GHz band 
by registering individual sites through a coordination mechanism that 
would be developed through government/industry collaboration.\3\ In the 
accompanying Further Notice of Proposed Rulemaking, the Commission 
defined the parameters for a successful coordination mechanism and 
sought comment on the most appropriate coordination mechanism for the 
band.\4\ In 2018, the Commission noted that the Lower 37 GHz band would 
innovatively accommodate a variety of use cases and sought comment on 
utilizing a third-party coordinator or alternatively, implementing a 
coordination model similar to that used in part 101 point-to-point 
bands.\5\
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    \3\ Use of Spectrum Bands Above 24 GHz For Mobile Radio 
Services, GN Docket No. 14-177, Report and Order and Further Notice 
of Proposed Rulemaking, 81 FR 79894, 31 FCC Rcd 8014, 8057-8060, 
paras. 105, 111, and 113 (2016) (2016 R&O or 2016 FNPRM, as 
appropriate).
    \4\ 2016 FNPRM, 81 FR 58270, 31 FCC Rcd at 8171, paras. 449-450.
    \5\ Use of Spectrum Bands Above 24 GHz For Mobile Radio 
Services, GN Docket No. 14-177, Third Report and Order, Memorandum 
Opinion and Order, and Third Further Notice of Proposed Rulemaking, 
83 FR 34520, 33 FCC Rcd 5576, 5602, paras. 63-64 (2018) (2018 
FNPRM).
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    National Spectrum Strategy. The NSS identified the Lower 37 GHz 
Band as a band for further study ``to implement a co-equal, shared-use 
framework allowing Federal and non-federal users to deploy operations 
in the band.'' \6\ The NSS Implementation Plan established a schedule 
under which a study of the band would be completed by October 2024 and 
a final report issued by November 2024.\7\ In order to aid in the study 
of the band and the preparation of the report, the Commission seeks 
public input on various issues relating to the Lower 37 GHz Band.\8\ 
The record developed in response to this Public Notice will be publicly 
available in WT Docket No. 24-243 and shared with the NTIA, the 
Department of Defense (DoD), and other interested agencies.
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    \6\ NSS at 7.
    \7\ NSS Implementation Plan at A-12.
    \8\ The Commission notes that another proceeding generated 
relevant comments regarding potential uses of the Lower 37 GHz band. 
See Shared Use of the 42-42.5 GHz Band, WT Docket No. 23-158, Notice 
of Proposed Rulemaking, 88 FR 49423, 38 FCC Rcd 6362 (2023).
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    Potential Uses of the Lower 37 GHz Band. The Commission finds that 
additional information on potential uses of the Lower 37 GHz band would 
be helpful in the preparation of the Lower 37 GHz Report. The current 
record on potential uses of the band is limited. While commenters 
foresee uses including fixed wireless broadband, point-to-point links, 
Internet of Things networks, device-to-device operations, augmented 
reality applications, smart cities, smart grids, and as part of private 
networks,\9\ they have not provided much detail about implementation of 
these services in the band. The Commission therefore asks interested 
operators to provide specific and updated information on the 
contemplated uses of the band, to include interdependencies of pairing 
spectrum bands with the Lower 37 GHz band. The Commission also seeks 
input regarding the feasibility of Aeronautical Mobile Service (AMS) 
operations within the band.\10\ This information will be helpful as we 
develop sharing mechanisms for the band. The Commission anticipates 
that operations offered in the band initially will be point-to-point 
and point-to-multipoint operations, although other types of 
operations--including mobile operations--may develop later. The 
Commission encourages commenters to explain how the various ideas 
presented below would facilitate or hinder contemplated operations.
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    \9\ See, e.g.. Comments of Starry, Inc., GN Docket No. 14-177 
(filed Sep. 10, 2018); Comments of Qualcomm, Inc., WT Docket No. 23-
158 and GN Docket No. 14-177 (filed Aug. 30, 2023) at 4; Comments of 
NCTA--The internet & Television Association, WT Docket No. 23-158 
and GN Docket No. 14-177 (filed Aug. 30, 2023) at 3-4.
    \10\ A new allocation would be required to allow Aeronautical 
Mobile Service to operate in the Lower 37 GHz band.
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    Coordination Framework. Under the contemplated framework, proposed 
operations must be successfully coordinated with the relevant Federal 
and non-federal operators before they can be registered. A coordination 
portal, where Federal and non-federal operators could generate phase 
one coordination contour(s), which identifies if further phase two 
coordination would be required, has been proposed. The Commission seeks 
input on the portal's capabilities in all phases and how the 
coordination portal could be funded. As referenced in the NSS,\11\ in 
2020 the Commission began intra-governmental collaboration with NTIA 
and DoD to further define and develop a possible coordination mechanism 
that permits the innovative type of spectrum sharing envisioned for the 
band. These conversations focused on balancing the desire to make this 
spectrum available expeditiously for deployment with the need to 
protect both Federal and non-federal operations in the band from 
harmful interference. In addition, the Commission intends that the 
framework be sufficiently flexible to accommodate multiple uses while 
also being simple enough to deploy more quickly than other more 
elaborate sharing mechanisms.
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    \11\ NSS at 7.
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    As an outgrowth of prior discussions with representatives from the 
Commission, NTIA, and DoD, a two-phase process emerged as a possible 
coordination mechanism to ensure meaningful access to spectrum by later 
entrants, including Federal entrants, while ensuring adequate 
protection from harmful interference to incumbents.\12\ In the first 
phase, an interference contour would be drawn around each existing and 
potential site based on its technical parameters, including transmitter 
details such as location (latitude and longitude), equivalent isotropic 
radiated power, antenna height, and antenna azimuth angle. The contour 
calculation would also take into account propagation loss due to 
terrain. If the prospective site's contour does not overlap with that 
of any existing registration, coordination is successful, and 
registration of the new site may proceed. If there is overlap, there 
would be a second phase of coordination, in which operators would 
communicate directly to discuss whether and under what circumstances a 
placement inside the relevant contours might be feasible. This phase 
would allow for more advanced interference mitigation techniques, such 
as antenna directivity, polarization, or shielding to provide solutions 
in specific situations without requiring a one-size-fits-all approach. 
The operators would be required to provide technical information on 
their respective operations \13\ and cooperate in good faith to 
determine whether coexistence would be possible. A dispute resolution 
process would be established to resolve any disputes that arose during 
the coordination process. The Commission seeks input on what 
information should

[[Page 68612]]

be included within a dispute resolution process. If the second phase of 
coordination is successfully achieved, the applicant would be permitted 
to register that particular site.
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    \12\ See Appendix A: Draft Lower 37 GHz Phase 1 Coordination 
Zone Contour Methodology and Appendix B: Draft Lower 37 GHz Phase 2 
Coordination Methodology, attached. The Commission also seeks input 
on the methodologies contained in these appendices, including the 
parameters proposed.
    \13\ DoD contemplates that in some instances there may be 
complications with data exchange due to data security concerns.
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    For non-federal site registrations, the technical details of the 
proposed site would be part of the registration and publicly available 
in the Universal Licensing System (ULS). For Federal site 
registrations, NTIA would maintain the relevant technical details. For 
non-federal coordination with Federal incumbents, these Federal site 
registration details would be queried during the first phase of 
coordination. That query would return either a green light (no contour 
overlap), or a yellow light (overlapping contours and potential 
interference risk); for a yellow light result, contact information for 
the relevant Federal agency would be provided to allow a non-federal 
applicant to proceed to phase two, as described above. The Commission 
seeks input on this coordination framework.
    Adjacent Band Protection. In the 2016 R&O, the Commission adopted 
an out-of-band emission limit that it concluded would ``keep emissions 
from an UMFUS device into the 36-37 GHz band well below the -10 dBW 
level specified by footnote US550A,'' noting that the -10 dBW power 
limit ``was adopted to protect passive sensors in the 36-37 GHz band in 
accordance with ITU Resolution 752 (WRC-07).'' \14\ Under FCC part 
30.203, operations are limited to -13 dBm/MHz, which expands to -13 
dBW/GHz. Subsequently, Resolution 243 (WRC-19), Table 1, established a 
-23 dBW/GHz unwanted emission mean power for IMT stations within the 
frequency band 36-37 GHz.\15\ In light of these developments, the 
Commission seeks input on whether additional measures are needed to 
protect spaceborne remote passive sensors in the 36-37 GHz band.
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    \14\ 2016 R&O, 81 FR 79894, 31 FCC Rcd at 8073, para. 156.
    \15\ Terrestrial component of International Mobile 
Telecommunications in the frequency bands 37-43.5 GHz and 47.2-48.2 
GHz, Resolution 243, WRC-19.
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    Licensing. For non-federal operations, the licensing process would 
consist of two steps. A non-federal entity seeking to operate in the 
Lower 37 GHz band would first obtain a nationwide non-exclusive license 
from the Commission, and then, following successful coordination, would 
register specific site locations in ULS. All registered site locations 
would be protected from harmful interference from any subsequent 
registrations, on a first-come first-served basis.\16\ Registered non-
federal sites would then generally be required to finish construction 
and begin operation within 120 days of the date the registration is 
accepted, or the registration would be cancelled, and the licensee 
would forfeit their interference protection priority. As discussed 
above, the Commission anticipates that most sites initially would be 
either point-to-point links or point-to-multipoint deployments, but 
this licensing process would potentially be able to accommodate other 
uses as well. The Commission seeks input on this licensing process.
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    \16\ First-in-time priority would apply to both Federal and non-
federal operations.
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    Priority Access. Consistent with the questions asked in the 2018 
FNPRM,\17\ the Commission envisions that the lower 200 megahertz band 
segment, 37.0-37.2 GHz, would be subject to priority use by DoD and 
military agency departments. The goal of this priority access would be 
to ensure that spectrum is available for military deployments, which 
may be on a longer timescale than commercial deployments. Military 
interests include pursuing air-to-ground use as part of a future 
sharing framework for the Lower 37 GHz band. This interest, in part, 
reflects the physics of the band inasmuch as in the upper atmosphere, 
the propagation is dominated by line-of-sight paths with reduced 
obstruction and atmospheric absorption. Given technology advancements 
since the adoption of the 2016 R&O, the Commission seeks input on this 
matter. The Commission also invites suggestions on the conditions under 
which non-federal users could operate in this portion of the band while 
maintaining the requisite flexibility for military deployments. For 
example, allowing non-federal users to register and deploy sites 
immediately, subject to a condition that they must modify or 
potentially cease operations in the future if those operations conflict 
with later military deployments could allow this spectrum to more 
quickly be put into use. Further, the Commission could impose 
conditions that specify that non-federal operators would not be 
protected from harmful interference from subsequent military 
deployments. The Commission seeks input on implementing priority 
access.
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    \17\ 2018 FNPRM, 83 FR 34520, 33 FCC Rcd at 5604, para. 68.
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    The Commission seeks input on these and any other suggestions for 
the use of this band, as we continue to explore options for making this 
spectrum available for shared use.
    Ensuring Widespread Access to Lower 37 GHz Spectrum. Given the 
limited number of channels available in the Lower 37 GHz band, the 
variety of potential uses of the band, and the fact that both Federal 
and non-federal entities will have access to the band, the Commission 
anticipates that initial demand for the band may exceed the available 
supply of channels in some areas. The Commission recognizes there is a 
risk, particularly in larger markets, that future entrants (both 
Federal and non-federal) may be precluded from accessing the band if 
the band is fully licensed in the initial licensing phase. On the other 
hand, the Commission wants operators to put this available spectrum to 
use quickly--both for non-federal and Federal uses--in order to serve 
the public interest.
    The Commission seeks input on what measures could be taken to 
control access to the Lower 37 GHz band during the initial site 
registration phase. For example, during this phase, applicants could be 
limited to a single 100 megahertz channel per site, which would ensure 
that multiple operators could access the band. Another possible 
approach would be to establish accelerated buildout deadlines (e.g., 60 
or 90 days) for registrations issued during the initial phase. That 
would provide some assurance that only bona fide operators who are 
ready to construct and commence operations file site registrations. 
Finally, to avoid cases where multiple applicants seek to register the 
same channel, the Commission could reserve the right to grant an 
applicant a different 100 megahertz channel than the channel it 
originally sought.
    Finally, the Commission seeks input on whether there are 
alternative measures that should be considered to enable multiple 
providers to operate in the Lower 37 GHz band.

Federal Communications Commission
John Schauble,
Deputy Division Chief, Broadband Division, Wireless Telecommunications 
Bureau.

Appendix A

Draft Lower 37 GHZ Phase 1 Coordination Zone Contour Methodology

Overview

    Application process initiated and validated at NTIA for Federal 
users and FCC for non-federal users
    Under Phase 1 Coordination:

--Establish coordination zone contour based on station type
--The same technical assumptions will apply to Federal and non-
federal users
--Identify overlap between coordination zone contours of existing 
and proposed systems

[[Page 68613]]

--If no overlap in coordination zone contours proposed station 
approved for licensing (non-federal stations) or frequency 
authorization (Federal stations), otherwise proceed to Phase 2 
(e.g., compatibility analysis performed by operators)
--Note: Provide an interference resolution process for non-
overlapping contours

1. Point-to-Multipoint Station Coordination Zone Contours

Transmitter Parameters (Provided by Federal and Non-Federal 
Applicant)

--Equivalent Isotropic Radiated Power (EIRP) (dBm/100 MHz)
--Latitude and Longitude (decimal degrees)
--Antenna Height (meters)

Reference Receiver

--Antenna Height: 10 meters

Coordination Trigger

--Power Spectral Density Threshold (PSDT): -110 dBm/100 MHz

Required Propagation Loss Calculation

--LRequired = EIRP--PSDT
--Irregular Terrain Model (ITM) and ITU-R Recommendation P.676 
atmospheric attenuation used to determine distance corresponding to 
LRequired
--ITM parameters provided in Table 1
--ITU-R P.676 parameters provided in Table 2
--No clutter loss

Coordination Zone Contours

--Use each distance for each radial to establish coordination zone 
contour

2. Base-to-Mobile Station Coordination Zone Contours

Transmitter Parameters (Provided by Federal and Non-Federal 
Applicant)

--Equivalent Isotropic Radiated Power (EIRP) (dBm/100 MHz)
--Latitude and Longitude (decimal degrees)
--Antenna Height (meters)

Reference Receiver

--Antenna Height: 1.5 meters

Coordination Trigger

--Power Spectral Density Threshold (PSDT): -110 dBm/100 MHz

Required Propagation Loss Calculation

--LRequired = EIRP--PSDT
--Irregular Terrain Model (ITM) and ITU-R Recommendation P.676 
atmospheric attenuation used to determine distance corresponding to 
LRequired
--ITM parameters provided in Table 1
--ITU-R P.676 parameters provided in Table 2
--No clutter loss

Coordination Zone Contours

--Use each distance for each radial to establish coordination zone 
contour

3. Coordination Zone Contours for Point-to-Point Stations

Parameters (Provided by Federal and Non-Federal Applicant)

--Equivalent Isotropic Radiated Power (EIRP) (dBm/100 MHz)
--Latitude and Longitude (decimal degrees)
--Transmitter and Receiver Antenna Height (meters)
--Antenna Azimuth Angle (degrees)

Reference Receiver

--Antenna Height: Provided by Applicant

Coordination Trigger

--Power Spectral Density Threshold (PSDT): -110 dBm/100 MHz

Required Propagation Loss Calculation

Key Hole Coordination Zone Contour Distance (Within 5[deg] 
of Mainbeam)

--Keyhole Angle: Fixed 5 degrees with respect to azimuth 
angle
--LRequired = EIRP--PSDT
--Irregular Terrain Model (ITM) and ITU-R Recommendation P.676 
atmospheric attenuation used to determine distance corresponding to 
LRequired
--ITM parameters provided in Table 1
--ITU-R P.676 parameters provided in Table 2
--No clutter loss

Circular Coordination Zone Contour Distance (5[deg] to 
15[deg] of Mainbeam)

--LRequired = EIRP--Antenna Discrimination Factor (ADF)--PSDT, where 
the ADF is 0 dB at 5 degrees off the axis of the main beam of the 
antenna and increases linearly at 3dB for each additional degree off 
axis up to 30 dB at 15 degrees off the axis of the main beam of the 
antenna.
--Irregular Terrain Model (ITM) and ITU-R Recommendation P.676 
atmospheric attenuation used to determine distance corresponding to 
LRequired
--ITM parameters provided in Table 1
--ITU-R P.676 parameters provided in Table 2
--No clutter loss

Circular Coordination Zone Contour Distance (15[deg] to 
45[deg] of Mainbeam)

--LRequired = EIRP-30 dB-PSDT
--Irregular Terrain Model (ITM) and ITU-R Recommendation P.676 
atmospheric attenuation used to determine distance corresponding to 
LRequired
--ITM parameters provided in Table 1
--ITU-R P.676 parameters provided in Table 2
--No clutter loss

Circular Coordination Zone Contour Distance (45[deg] to 
55[deg] of Mainbeam)

--LRequired = EIRP-ADF-PSDT, where the ADF is 30 dB at 45 degrees 
off the axis of the main beam of the antenna and increases linearly 
at 1dB for each additional degree off axis up to 40dB at 55 degrees 
off the axis of the main beam of the antenna.
--Irregular Terrain Model (ITM) and ITU-R Recommendation P.676 
atmospheric attenuation used to determine distance corresponding to 
LRequired
--ITM parameters provided in Table 1
--ITU-R P.676 parameters provided in Table 2
--No clutter loss

Circular Coordination Zone Contour Distance (55[deg] to 
80[deg] of Mainbeam)

--LRequired = EIRP-40 dB-PSDT
--Irregular Terrain Model (ITM) and ITU-R Recommendation P.676 
atmospheric attenuation used to determine distance corresponding to 
LRequired
--ITM parameters provided in Table 1
--ITU-R P.676 parameters provided in Table 2
--No clutter loss

Circular Coordination Zone Contour Distance (80[deg] to 
100[deg] of Mainbeam)

--LRequired = EIRP-ADF-PSDT,, where the ADF is 40 dB at 80 degrees 
off the axis of the main beam of the antenna and increases linearly 
at 0.5 dB for each additional degree off axis up to 50 dB at 100 
degrees off the axis of the main beam of the antenna.
--Irregular Terrain Model (ITM) and ITU-R Recommendation P.676 
atmospheric attenuation used to determine distance corresponding to 
LRequired
--ITM parameters provided in Table 1
--ITU-R P.676 parameters provided in Table 2
--No clutter loss

Circular Coordination Zone Contour Distance (outside of 100[deg] of Mainbeam)

--LRequired = EIRP-50 dB-PSDT
--Irregular Terrain Model (ITM) and ITU-R Recommendation P.676 
atmospheric attenuation used to determine distance corresponding to 
LRequired
--ITM parameters provided in Table 1
--ITU-R P.676 parameters provided in Table 2
--No clutter loss

Coordination Zone Contours

--Use each distance for each radial to establish coordination zone 
contour starting from system location

  Table 1--ITM Parameters Used in Coordination Zone Contour Generation
                                  \18\
------------------------------------------------------------------------
               Parameter                              Value
------------------------------------------------------------------------
Frequency..............................  37 GHz.
Mode...................................  Terrain Dependent.
Transmitter Antenna Height (Above        Provided by Applicant.
 Ground Level).
Reference Receiver Antenna Height        Point-to-Multipoint: 10 meters
 (Above Ground Level).                    Base-to-Mobile: 1.5 meters
                                          Point-to-Point: Provided by
                                          Applicant.

[[Page 68614]]

 
Transmitter Location...................  Latitude (Decimal Degrees) and
                                          Longitude (Decimal Degrees).
Mode of Variability....................  Single Message.
Surface Refractivity...................  301 N-Units.
Dielectric Constant of Ground..........  15.
Radio Climate..........................  Continental Temperate.
Reliability............................  50%.
Confidence.............................  50%.
Terrain Data...........................  United States Geological Survey
                                          1-Second.
Atmospheric Attenuation................  Recommendation ITU-R P.676
                                          \19\.
Number of Radials......................  360 (1 Degree Increments).
Spacing Along Radial...................  30 meters.
Distance Criteria......................  1st point along radial where
                                          the required path loss is
                                          achieved.
------------------------------------------------------------------------


                  Table 2--ITU-R P.676 Parameter Inputs
------------------------------------------------------------------------
               Parameter                              Value
------------------------------------------------------------------------
Frequency..............................  37 GHz.
Air Temperature........................  23 C.
Surface Atmospheric Pressure...........  1013.25 hPa.
Ground-level Water Vapor Density.......  7.5 g/m3.
------------------------------------------------------------------------

Station Definitions \20\
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    \18\ National Telecommunications and Information Administration, 
NTIA Report 82-100, A Guide to the Use of the ITS Irregular Terrain 
Model in the Area Prediction Mode (April 1982).
    \19\ Recommendation ITU-R P.676-12, Attenuation by atmospheric 
gases and related effects (Aug. 2019). The model in ITM is limited 
to an upper frequency limit of 20 GHz. ITM does not explicitly 
compute gaseous attenuation (the remaining propagation loss models 
in ITM are not affected by going to higher frequencies). By 
augmenting (i.e., adding) the basic transmission losses predicted by 
ITM with the product of the P.676 specific attenuations (dB/km) and 
the path distance (in consistent units), the basic transmission loss 
will include gaseous attenuation that is required.
    \20\ These station definitions are taken from, or based on, the 
definitions set forth in 47 CFR 30.2.
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    Point-to-Multipoint Hub Station. A fixed point-to-multipoint 
radio station that provides one-way or two-way communication with 
fixed Point-to-Multipoint Service User Stations.
    Point-to-Multipoint Service. A fixed point-to-multipoint radio 
service consisting of point-to- multipoint hub stations that 
communicate with fixed point-to-multipoint user stations.
    Point-to-Multipoint User Station. A fixed radio station located 
at users' premises, lying within the coverage area of a Point-to-
Multipoint Hub station, using a directional antenna to receive one-
way communications from or providing two-way communications with a 
fixed Point-to- Multipoint Hub Station.
    Point-to-point station. A station that transmits a highly 
directional signal from a fixed transmitter location to a fixed 
receive location.
    Transportable station. Transmitting equipment that communicates 
with a base station and is not intended to be used while in motion, 
but rather at stationary locations.
    Base station. A fixed station that communicates with mobile or 
transportable stations.
    Mobile station. A station in the mobile service intended to be 
used while in motion or during halts at unspecified points.\21\
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    \21\ This station definition is taken from the FCC rules. See 47 
CFR 2.1.
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Appendix B

Draft Lower 37 GHZ Phase 2 Coordination Methodology

Overview

    The phase two coordination methodology provides guidance to the 
operators (Federal and non-federal) performing compatibility 
analysis when there is an overlap in the coordination contours 
generated in Phase 1.
    When phase one contours overlap and trigger phase two 
coordination, the applicant will contact the incumbent, who should 
provide a response within 15 working days.
    Under Phase 2 Coordination:

--Parties should exchange technical characteristics to perform 
compatibility analysis.
--Operators should negotiate in good faith and work cooperatively.
--The same Phase 1 technical assumptions will apply to Federal and 
non-federal users. Additional Phase 2 coordination may apply agreed 
upon models.
--Applicable propagation terrain and building databases should be 
used when available.
--Operators should take full advantage of interference mitigation 
techniques such as antenna directivity, polarization, frequency 
selection, shielding, site selection, and transmitter power control 
to facilitate the implementation, operation, compatibility between 
systems.
--A dispute resolution process will be established by FCC and NTIA 
to resolve disagreements between operators that arise during the 
coordination process.

Technical Parameters for Phase 2 Coordination

    Table 1 provides the technical parameters to be exchanged 
between operators for the Lower 37 GHz Phase 2 Coordination. If 
operators agree, a subset or additional technical parameters can be 
exchanged for the compatibility analysis.
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    \22\ Emission Bandwidth is synonymous with the definition of 
occupied bandwidth in the ITU radio regulations and FCC rules--
Occupied bandwidth. The frequency bandwidth such that, below its 
lower and above its upper frequency limits, the mean powers radiated 
are each equal to 0.5 percent of the total mean power radiated by a 
given emission.
    \23\ National Spectrum Management Association.

           Table 1--Phase 2 Coordination Technical Parameters
------------------------------------------------------------------------
       Technical parameter               Units             Comments
------------------------------------------------------------------------
Transmitter Geographic            Degrees/Minutes/    ..................
 Coordinates.                      Seconds.
Transmitter Antenna Ground        Meters............  Above Mean Sea
 Elevation.                                            Level (as
                                                       indicated by the
                                                       USGS terrain
                                                       database).
Transmitter Antenna Height......  Meters............  Above Ground
                                                       Level.

[[Page 68615]]

 
Transmitter Power...............  dBm...............  ..................
Mainbeam Antenna Gain...........  dBi...............  ..................
Equivalent Isotropic Radiated     dBm...............  ..................
 Power.
Center Frequency................  MHz...............  ..................
Emission Bandwidth \22\.........  MHz...............  ..................
Emission Designator.............  Emission            ..................
                                   Classification
                                   Symbols.
Emission Spectrum...............  Relative            -3 dB, -20 dB, -60
                                   Attenuation (dB)    dB points.
                                   as a Function of
                                   Frequency Offset
                                   from Center
                                   Frequency (MHz).
Transmitter Antenna Azimuth of    Degrees...........  With Respect to
 Maximum Gain.                                         True North.
Transmitter Antenna Downtilt/     Degrees...........  With Respect to
 Uptilt (Elevation) Angle.                             Horizontal.
Transmit Antenna Polarization...  ..................  ..................
Transmitter Azimuth Off-Axis      dBi as a function   Required for all
 Antenna Pattern.                  of off-axis angle   use cases; point-
                                   in degrees.         to-point systems
                                                       should use NSMA
                                                       \23\ Format.
Transmitter Elevation Off-Axis    dBi as a function   Required for all
 Antenna Pattern.                  of off-axis angle   use cases; point-
                                   in degrees.         to-point systems
                                                       should use NSMA
                                                       Format.
Transmitter Cable/Insertion Loss  dB................  ..................
Receiver Geographic Coordinates.  Degrees/Minutes/    ..................
(Point to Point Systems Only)...   Seconds.
Receiver Antenna Ground           Meters............  Above Mean Sea
 Elevation (Point to Point                             Level (as
 Systems Only).                                        indicated by the
                                                       USGS terrain
                                                       database).
Receiver Antenna Height (Point-   Meters............  Above Ground
 to-Point Systems Only).                               Level.
Receiver Mainbeam Antenna Gain..  dBi...............  ..................
Receiver Threshold/Sensitivity..  dBm...............  Minimum
                                                       Discernible
                                                       Single/Criteria.
Receiver Noise Figure...........  dB................  ..................
Receiver IF Selectivity.........  Relative            -3 dB, -20 dB, -60
                                   Attenuation (dB)    dB points.
                                   as a Function of
                                   Frequency Offset
                                   from Center
                                   Frequency (MHz).
Receiver Antenna Azimuth of       Degrees...........  With Respect to
 Maximum Gain.                                         True North.
Receiver Antenna Downtilt/Uptilt  Degrees...........  With Respect to
 (Elevation) Angle.                                    Horizontal.
Receive Antenna Polarization....  ..................  ..................
Receiver Azimuth Off-Axis         dBi as a function   Required for all
 Antenna Pattern.                  of off-axis angle   use cases; point-
                                   in degrees.         to-point systems
                                                       should use NSMA
                                                       Format.
Receiver Elevation Off-Axis       dBi as a function   Required for all
 Antenna Pattern.                  of off-axis angle   use cases; point-
                                   in degrees.         to-point systems
                                                       should use NSMA
                                                       Format.
Receiver Cable/Insertion Loss...  dB................  ..................
------------------------------------------------------------------------

Interference Criteria for Phase 2 Coordination

    The interference criteria for the Phase 2 coordination are set 
forth in Table 2. If coordinating parties are able to agree on 
mutually acceptable alternative interference criteria, such 
alternative criteria may be used in the compatibility analysis.

   Table 2--Phase 2 Coordination Interference Criteria Use Case Matrix
------------------------------------------------------------------------
                                  Incumbent use
      Applicant use case               case        Interference criteria
------------------------------------------------------------------------
B-M...........................  B-M..............  Receiver Noise--6 dB.
B-M...........................  P-MP.............  Receiver Noise--6 dB.
B-M...........................  P-P..............  Receiver Noise--6 dB.
P-MP..........................  P-MP.............  Receiver Noise--6 dB.
P-MP..........................  B-M..............  Receiver Noise--6 dB.
P-MP..........................  P-P..............  Receiver Noise--6 dB.
P-P...........................  P-P..............  Receiver Noise--6 dB.
P-P...........................  B-M..............  Receiver Noise--6 dB.
P-P...........................  P-MP.............  Receiver Noise--6 dB.
------------------------------------------------------------------------
Receiver Noise = -114 + 10 Log IFBW + NF (Noise temperature is assumed
  to be 290 degrees Kelvin (room temperature) for all systems using this
  band)
IFBW is the receiver 3 dB intermediate frequency bandwidth, in MHz, if
  available. If not available, emission bandwidth may be used.
NF is the receiver noise figure, in dB
I/N of -6dB, used to determine the interference criteria unless another
  interference criteria is identified and agreed to by Federal and non-
  federal operators


[[Page 68616]]

Compatibility Analysis

    The following general equation will be used to calculate the 
received interference power at the input of a receiver: \24\
---------------------------------------------------------------------------

    \24\ The link budget analysis approach used is described in 
Joint Spectrum Center, JSC-CR-10-004, Communications Receiver 
Performance Degradation Handbook (Aug. 11, 2010), Section 2, 
available at https://www.ntia.doc.gov/files/ntia/publications/jsc-cr-10-004final.pdf.

PR = PT + GT + GR - LP - LT - LR - LC - LA - LPol - FDR (1)
where:
PT is the transmitter power (dBm);
EIRP is the equivalent isotropically radiated power of the 
transmitter (dBm); GT is the transmitter antenna gain in the 
direction of the receiver (dBi);
GR is the receiver antenna gain in the direction of the receiver 
(dBi); LP is the basic transmission loss, in the absence of clutter 
(dB);
LT is the transmitter cable/insertion losses (dB); LR is the 
receiver cable/insertion losses (dB); LC is the clutter loss (dB);
LA is the atmospheric loss (dB);
LPol is the polarization loss (dB); and
FDR is the Frequency Dependent Rejection (dB)
    The compatibility analysis only considers single-entry 
interference. If operators mutually agree to do so, they may 
consider aggregate interference.
    The computed receiver interference power will be compared to 
interference criteria to determine whether there is compatibility. 
The operators may exchange the interference threshold exceedance 
once the analysis is complete.
    The amount in dB that the calculated interference from Equation 
1 exceeds the interference criteria specified in Table 2 will be 
exchanged between the Federal and non-federal users.

Antenna Models

    Measured antenna patterns are preferred and should be used 
whenever available; in their absence, the operators may use modeled 
antenna patterns provided by the manufacturer, or a model that 
estimates the antenna pattern.\25\
---------------------------------------------------------------------------

    \25\ For an active Advanced Antenna System (AAS) in the lower 37 
GHz band ITU-R M.2101 contains a possible antenna model for a single 
element and composite pattern. For non-AAS, ITU-R F.1336 may be 
considered.
---------------------------------------------------------------------------

Propagation Model

    To calculate the propagation loss, operators may mutually agree 
to apply proprietary propagation models, actual measurement data, or 
other environmental data, consistent with good engineering 
practices. Both operators must agree on and accept the results of 
the analysis performed using the agreed-upon methodology. The Phase 
2 coordination analysis should not consider worst-case conditions 
unless otherwise justified.
    Coordinating parties may consider the use of open-source 
propagation models such as ITM and ITU-R P.676.\26\ Annex 1 of this 
document contains the suggested propagation model inputs and 
application descriptions.
---------------------------------------------------------------------------

    \26\ ITU-R P.452 is another open-source propagation model that 
can be implemented if both parties agree to it.
---------------------------------------------------------------------------

Clutter Loss Model

    The operators may mutually agree to use proprietary clutter loss 
and building height databases. Operators may also consider using 
ITU-R P.2108, an open-source statistical clutter loss model.

Variation Acceptance in Analysis Results

    Using the methodology in this document, it is possible for both 
operators to produce different analysis results if they choose to 
implement each model individually. Therefore, the operators are 
encouraged to exchange analysis results to resolve differences. The 
FCC and NTIA will establish a dispute resolution process through 
which operators can discuss their analyses and adjudicate disputes 
through NTIA and the FCC.

Annex 1

    This section provides a brief description of public models that 
can be used to calculate propagation loss, LP in equation 1. The 
models herein assume all operations are outdoor and all transmitters 
and receivers have fixed antenna heights.

ITM + ITU R P. 676

Application

    This model might be used to calculate the propagation loss for 
paths in suburban and rural environments. ITM requires an array of 
terrain elevations as an input. A terrain database and terrain 
elevation extraction methods will be required to obtain the terrain 
elevations. ITM only considers bare-earth obstruction without any 
building, vegetation or other material clutter losses.

Source Code

NTIA/itm: The Irregular Terrain Model (ITM) (github.com)

                      Table 1--ITM Input Parameters
------------------------------------------------------------------------
               Parameter                              Value
------------------------------------------------------------------------
Frequency..............................  Operating Frequency (GHz).
Mode...................................  Terrain Dependent.
Transmitter Antenna Height (Above        Provided by Applicant.
 Ground Level).
Reference Receiver Antenna Height        Point-to-Multipoint: 10 meters
 (Above Ground Level).                    Base-to-Mobile: 1.5 meters
                                          Point-to-Point: Provided by
                                          Applicant.
Transmitter Location...................  Latitude (Decimal Degrees) and
                                          Longitude (Decimal Degrees).
Mode of Variability....................  Single Message.
Surface Refractivity...................  301 N-Units.
Dielectric Constant of Ground..........  15.
Radio Climate..........................  Continental Temperate.
Reliability............................  50%.
Confidence.............................  50%.
------------------------------------------------------------------------


                  Table 3--ITU-R P.676 Input Parameters
------------------------------------------------------------------------
                 Parameter                              Value
------------------------------------------------------------------------
Frequency.................................  37 GHz.
Air Temperature...........................  23 C.
Surface Atmospheric Pressure..............  1013.25 hPa.
Ground-level Water Vapor Density..........  7.5 g/m3.
------------------------------------------------------------------------

[FR Doc. 2024-19081 Filed 8-26-24; 8:45 am]
BILLING CODE 6712-01-P