2024-19081. Information Sought on Sharing the Lower 37 GHz Band in Connection With the National Spectrum Strategy Implementation Plan

Table 1—ITM Parameters Used in Coordination Zone Contour Generation ¹⁸

Parameter	Value
Frequency	37 GHz.
Mode	Terrain Dependent.
Transmitter Antenna Height (Above Ground Level)	Provided by Applicant.
Reference Receiver Antenna Height (Above Ground Level)	Point-to-Multipoint: 10 meters Base-to-Mobile: 1.5 meters Point-to-Point: Provided by Applicant.
( print 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

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]

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.

Table 1—Phase 2 Coordination Technical Parameters

Technical parameter	Units	Comments
Transmitter Geographic Coordinates	Degrees/Minutes/Seconds
Transmitter Antenna Ground Elevation	Meters	Above Mean Sea Level (as indicated by the USGS terrain database).
Transmitter Antenna Height	Meters	Above Ground Level.
( print page 68615)
Transmitter Power	dBm
Mainbeam Antenna Gain	dBi
Equivalent Isotropic Radiated Power	dBm
Center Frequency	MHz
Emission Bandwidth 22	MHz
Emission Designator	Emission Classification Symbols
Emission Spectrum	Relative Attenuation (dB) as a Function of Frequency Offset from Center Frequency (MHz)	-3 dB, -20 dB, -60 dB points.
Transmitter Antenna Azimuth of Maximum Gain	Degrees	With Respect to True North.
Transmitter Antenna Downtilt/Uptilt (Elevation) Angle	Degrees	With Respect to Horizontal.
Transmit Antenna Polarization
Transmitter Azimuth Off-Axis Antenna Pattern	dBi as a function of off-axis angle in degrees	Required for all use cases; point-to-point systems should use NSMA 23 Format.
Transmitter Elevation Off-Axis Antenna Pattern	dBi as a function of off-axis angle in degrees	Required for all use cases; point-to-point systems should use NSMA Format.
Transmitter Cable/Insertion Loss	dB
Receiver Geographic Coordinates (Point to Point Systems Only)	Degrees/Minutes/Seconds
Receiver Antenna Ground Elevation (Point to Point Systems Only)	Meters	Above Mean Sea Level (as indicated by the USGS terrain database).
Receiver Antenna Height (Point-to-Point Systems Only)	Meters	Above Ground Level.
Receiver Mainbeam Antenna Gain	dBi
Receiver Threshold/Sensitivity	dBm	Minimum Discernible Single/Criteria.
Receiver Noise Figure	dB
Receiver IF Selectivity	Relative Attenuation (dB) as a Function of Frequency Offset from Center Frequency (MHz)	-3 dB, -20 dB, -60 dB points.
Receiver Antenna Azimuth of Maximum Gain	Degrees	With Respect to True North.
Receiver Antenna Downtilt/Uptilt (Elevation) Angle	Degrees	With Respect to Horizontal.
Receive Antenna Polarization
Receiver Azimuth Off-Axis Antenna Pattern	dBi as a function of off-axis angle in degrees	Required for all use cases; point-to-point systems should use NSMA Format.
Receiver Elevation Off-Axis Antenna Pattern	dBi as a function of off-axis angle in degrees	Required for all use cases; point-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

Applicant use case	Incumbent use 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

( print page 68616)

Compatibility Analysis

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

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]

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.

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 Ground Level)	Provided by Applicant.
Reference Receiver Antenna Height (Above Ground Level)	Point-to-Multipoint: 10 meters 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.