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Recommendation ITU-R P.2108-1 - U.S. Reference Implementation

Persistent Identifier: DOI

This code repository contains the U.S. Reference Software Implementation of Recommendation ITU-R P.2108. This Recommendation contains three methods for the prediction of clutter loss: Height Gain Terminal Correction Model, Terrestrial Statistical Model, Aeronautical Statistical Model. The software implements Section 3 of Annex 1 of the Recommendation.

Height Gain Terminal Correction Model

The height gain terminal correction model is described in Section 3.1. This end-point clutter method gives the median loss due to different terminal surroundings for terrestrial paths for frequencies between 0.3 to 3 GHz. This model can be applied to both transmitting and receiving ends of the path.

Inputs (Height Gain Terminal Correction Model)

Variable Type Units Limits Description
f__ghz double GHz 0.3 <= f__ghz <= 3 Frequency
h__meter double meter 0 <= h__meter Antenna height
w_s__meter double meter 0 < w_s__meter Street width
R__meter double meter 0 < R__meter Representative clutter height
clutter_type int Clutter type
  • 1 = Water/sea
  • 2 = Open/rural
  • 3 = Suburban
  • 4 = Urban
  • 5 = Trees/forest
  • 6 = Dense urban

Where site-specific values for the representative clutter height are not available, the following default values are recommended.

Clutter Type R__meter
Water/sea 10
Open/rural 10
Suburban 10
Urban 15
Trees/forest 15
Dense urban 20

Outputs (Height Gain Terminal Correction Model)

Variable Type Units Description
A_h__db double dB Additional loss (clutter loss)

Return Codes (Height Gain Terminal Correction Model)

Possible return codes, including the corresponding defined constant name as defined in Errors.h:

Value Const Name Description
0 SUCCESS Successful execution
3100 ERROR31__FREQUENCY Frequency must be between 0.3 and 3 GHz, inclusive
3101 ERROR31__ANTENNA_HEIGHT Antenna height must be >= 0 meters
3102 ERROR31__STREET_WIDTH Street width must be > 0 meters
3103 ERROR31__CLUTTER_HEIGHT Representative clutter height must be > 0 meters
3104 ERROR31__CLUTTER_TYPE Invalid value for clutter type

Terrestrial Statistical Model

The statistical clutter loss model for terrestrial paths as described in Section 3.2. This model is valid for urban and suburban clutter environments. For paths between 0.25 and 1 km, this model can only be applied to one end of the path. For paths greater than 1 km, the model can be applied to both terminals, if desired.

Inputs (Terrestrial Statistical Model)

Variable Type Units Limits Description
f__ghz double GHz 2 <= f__ghz <= 67 Frequency
d__km double km 0.25 <= d__km Path distance
p double % 0 < p < 100 Percentage of locations clutter loss not exceeded

Outputs (Terrestrial Statistical Model)

Variable Type Units Description
L_ctt__db double dB Clutter loss

Return Codes (Terrestrial Statistical Model)

Possible return codes, including the corresponding defined constant name as defined in Errors.h:

Value Const Name Description
0 SUCCESS Successful execution
3200 ERROR32__FREQUENCY Frequency must be between 2 and 67 GHz, inclusive
3201 ERROR32__DISTANCE Path distance must be >= 0.25 km
3202 ERROR32__PERCENTAGE Percentage must be between 0 and 100

Aeronautical Statistical Model

The Earth-space and aeronautical statistical clutter loss model as described in Section 3.3. This model is applicable when one end of the path is within man-made clutter and the other end is a satellite, aeroplane, or other platform above the Earth. This model is valid for urban and suburban clutter environments.

Inputs (Aeronautical Statistical Model)

Variable Type Units Limits Description
f__ghz double GHz 10 <= f__ghz <= 100 Frequency
theta__deg double deg 0 <= theta__deg <= 90 Elevation angle
p double % 0 < p < 100 Percentage of locations clutter loss not exceeded

Outputs (Aeronautical Statistical Model)

Variable Type Units Description
L_ces__db double dB Clutter loss

Return Codes (Aeronautical Statistical Model)

Possible return codes, including the corresponding defined constant name as defined in Errors.h:

Value Const Name Description
0 SUCCESS Successful execution
3300 ERROR33__FREQUENCY Frequency must be between 10 and 100 GHz, inclusive
3301 ERROR33__THETA Elevation angle must be between 0 and 100 GHz, inclusive
3302 ERROR33__PERCENTAGE Percentage must be between 0 and 100, inclusive

Example Values

The Study Group Clutter Excel Workbook contains an extensive set of validation example values.

Notes on Code Style

  • In general, variables follow the naming convention in which a single underscore denotes a subscript (pseudo-LaTeX format), where a double underscore is followed by the units, i.e. h_1__meter.
  • Variables are named to match their corresponding mathematical variables in the underlying Recommendation text.
  • Wherever possible, equation numbers are provided. It is assumed that a user reviewing this source code would have a copy of the Recommendation's text available as a primary reference.

Configure and Build

C++ Software

The software is designed to be built into a DLL (or corresponding library for non-Windows systems). The source code can be built for any OS that supports the standard C++ libraries. A Visual Studio 2019 project file is provided for Windows users to support the build process and configuration.

C#/.NET Wrapper Software

The .NET support of P.2108 consists of a simple pass-through wrapper around the native DLL. It is compiled to target .NET Framework 4.8.1. Distribution and updates are provided through the published NuGet package.

References

Contact

For questions, contact Billy Kozma, wkozma@ntia.gov