Recommendation ITU-R P.2108

Published

June 28, 2024

Modified

November 20, 2024

Recommendation ITU-R P.2108 Prediction of clutter loss contains three methods for the prediction of clutter loss: the Height Gain Terminal Correction Model, Terrestrial Statistical Model, and Aeronautical Statistical Model [1, Secs. 3.1–3.3]. This software implements each of the three models.

Getting Started

This page documents the inputs, outputs, and primary functions of this software in a language-agnostic way. Language-specific documentation is additionally provided for this library. The pages linked below include installation instructions as well as usage examples for each supported language.

C++ .NET MATLAB Python

Model Selection

Selection and use of the appropriate model is required to obtain meaningful outputs. Refer to Table 1 from [1, Sec. 2] for a summary of the applicable scenarios for each model. Further details about the applicability and assumptions of each of the P.2108 models are available in the sections of the Recommendation in which they are described.

Functions

Height Gain Terminal Correction Model

The height gain terminal correction model is described in [1, Sec. 3.1]. This model calculates an additional loss, \(A_h\), which can be added to the basic transmission loss of a path calculated above the clutter. Therefore basic transmission loss should be calculated to/from the height of the representative clutter height used. This model can be applied to both transmitting and receiving ends of the path.

Table 1: Inputs for the height gain terminal correction model

Variable	Type	Units	Limits	Description
`f__ghz`	double	GHz	\(0.03 \leq f \leq 3\)	Frequency
`h__meter`	double	meter	\(0 \leq h\)	Antenna height
`w_s__meter`	double	meter	\(0 < w_s\)	Street width
`R__meter`	double	meter	\(0 < R\)	Representative clutter height
`clutter_type`	`ClutterType` enum	N/A	enum	See Table 2

The values for \(w_s\) and \(R\) should be set based upon local information. If local information is not available, [1, Sec. 3.1.1] defines appropriate default values: \(w_s=27\) and a set of values for \(R\) based on the clutter type, which are reproduced in Table 2. This table also provides the integer values mapped to each clutter type in the enumeration objects are provided by the software for ease of use.

Table 2: Clutter types for the [1, Sec. 3.1] model

Clutter Type	Enum Value	Default \(R\) (m)
Water/sea	1	10
Open/rural	2	10
Suburban	3	10
Urban	4	15
Trees/forest	5	15
Dense urban	6	20

Examples

Language-specific code examples showing the use of this function are available by following these links:

C++ .NET MATLAB Python

Terrestrial Statistical Model

The terrestrial statistical model is described in [1, Sec. 3.2]. The model can be applied for urban and suburban environments provided terminal heights are well below the clutter height. The correction produced by this model can be applied at one terminal, or, if the path length is at least 1 km, at both terminals.

This model calculates an additional loss, \(L_{ctt}\), which can be added to the transmission loss or basic transmission loss. As this is a statistical model, the term \(L_{ctt}\) is the clutter loss not exceeded for \(p\) percent of locations for a terrestial path of length \(d\). If the transmission loss or basic transmission loss has been calculated using a model that inherently accounts for clutter over the entire path then this model should not be applied.

Table 3: Inputs for the terrestrial statistical model

Variable	Type	Units	Limits	Description
`f__ghz`	double	GHz	\(0.5 \leq f \leq 67\)	Frequency
`d__km`	double	km	\(0.25 \leq d\)	Path distance. Must be \(\geq 1\) km to apply the correction at both ends of the path.
`p`	double	%	\(0 < p < 100\)	Percentage of locations at which predicted clutter loss will not be exceeded

Examples

Language-specific code examples showing the use of this function are available by following these links:

C++ .NET MATLAB Python

Aeronautical Statistical Model

The Earth-space and aeronautical statistical clutter loss model is described in [1, Sec. 3.3]. This model is applicable when one terminal is within man-made clutter and the other is a satellite, aeroplane, or other platform above the surface of the Earth. The model is applicable to urban and suburban clutter environments.

This model calculates an additional loss, \(L_{ces}\), which can be added to the basic transmission loss of a path calculated. As this is a statistical model, the term \(L_{ces}\) is the clutter loss not exceeded for \(p\) percent of locations.

The method used to develop this model is described in [2].

Table 4: Inputs for the aeronautical statistical model

Variable	Type	Units	Limits	Description
`f__ghz`	double	GHz	\(10 \leq f \leq 100\)	Frequency
`theta__deg`	double	degree	\(0 \leq \theta \leq 90\)	Elevation angle
`p`	double	%	\(0 < p < 100\)	Percentage of locations at which predicted clutter loss will not be exceeded

Examples

Language-specific code examples showing the use of this function are available by following these links:

C++ .NET MATLAB Python

References

[1]

“Prediction of clutter loss,” International Telecommunications Union, Recommendation ITU-R P.2108-1, Sep. 2021. Available: https://www.itu.int/rec/R-REC-P.2108

[2]

“A method to predict the statistics of clutter loss for earth-space and aeronautical paths,” International Telecommunications Union, Recommendation ITU-R P.2402-0, Mar. 2017. Available: https://www.itu.int/pub/R-REP-P.2402-2017