propagationModel

Create RF propagation model

Syntax

pm = propagationModel(modelname)

pm = propagationModel(___,Name,Value)

Description

pm = propagationModel(modelname) creates an RF propagation model for the specified model.

pm = propagationModel(___,Name,Value) specifies options using name-value arguments. For example, pm = propagationModel('rain','RainRate',96) creates a rain propagation model with a rain rate of 96 mm/h.

Examples

Signal Strength of Receiver in Heavy Rain

Specify transmitter and receiver sites.

tx = txsite('Name','MathWorks Apple Hill',...
       'Latitude',42.3001, ...
       'Longitude',-71.3504, ...
       'TransmitterFrequency', 2.5e9);
 
rx = rxsite('Name','Fenway Park',...
       'Latitude',42.3467, ...
       'Longitude',-71.0972);

Create the propagation model for a heavy rainfall rate.

pm = propagationModel('rain','RainRate',50)

pm = 
  Rain with properties:

    RainRate: 50
        Tilt: 0

Calculate the signal strength at the receiver using the rain propagation model.

ss = sigstrength(rx,tx,pm)

ss = -87.1559

Longley-Rice Propagation Model

Create a default transmitter site.

tx = txsite;

Create a Longley-Rice propagation model by using the propagationModel function.

pm = propagationModel("longley-rice","TimeVariabilityTolerance",0.7)

pm = 
  LongleyRice with properties:

              AntennaPolarization: 'horizontal'
               GroundConductivity: 0.0050
               GroundPermittivity: 15
          AtmosphericRefractivity: 301
                      ClimateZone: 'continental-temperate'
         TimeVariabilityTolerance: 0.7000
    SituationVariabilityTolerance: 0.5000

Find the coverage of the transmitter site by using the defined propagation model.

coverage(tx,"PropagationModel",pm)

Input Arguments

modelname — Name of propagation model

'freespace' | 'rain' | 'gas' | 'fog' | 'close-in' | 'longley-rice' | 'tirem' | 'raytracing'

Name of propagation model, specified as one of these:

• 'freespace' — Free space propagation model.

• 'rain' — Rain propagation model. For more information, see [3].

• 'gas' — Gas propagation model. For more information, see [6].

• 'fog' — Fog propagation model. For more information, see [2].

• 'close-in' — Close-in propagation model typically used in urban macro-cell scenarios. For more information, see [1].

  Note

  The close-in model implements a statistical path loss model and can be configured for different scenarios. The default values correspond to an urban macro-cell scenario in a non-line-of-sight (NLOS) environment.

• 'longley-rice' — Longley-Rice propagation model. This model is also known as Irregular Terrain Model (ITM). You can use this model to calculate point-to-point path loss between sites over an irregular terrain, including buildings. Path loss is calculated from free-space loss, terrain diffraction, ground reflection, refraction through atmosphere, tropospheric scatter, and atmospheric absorption. For more information and list of limitations, see [4].

  Note

  The Longley-Rice model implements the point-to-point mode of the model, which uses terrain data to predict the loss between two points.

• 'tirem' — Terrain Integrated Rough Earth Model™ (TIREM™). You can use this model to calculate point-to-point path loss between sites over an irregular terrain, including buildings. Path loss is calculated from free-space loss, terrain diffraction, ground reflection, refraction through atmosphere, tropospheric scatter, and atmospheric absorption. This model needs access to an external TIREM library. The actual model is valid from 1 MHZ to 1000 GHz. But with Antenna Toolbox™ elements and arrays the frequency range is limited to 200 GHz.

• 'raytracing' — A multipath propagation model that uses ray tracing analysis to compute propagation paths and corresponding path losses. Path loss is calculated from free-space loss, reflection loss due to material, and antenna polarization loss. You can perform ray tracing analysis using the shooting and bouncing rays (SBR) method or the image method. Specify a method using the 'Method' property. The SBR method includes effects from surface reflections but does not include effects from diffraction, refraction, or scattering. The image method considers surface reflection only. Both ray tracing methods are valid for a frequency range of 100 MHz to 100 GHz. For information about differences between the image and SBR methods, see Choose a Propagation Model. Use the raytrace function to compute and plot the propagation paths between the sites.

Data Types: char

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: propagationModel("rain","RainRate",50) sets the rate of rainfall in the rain propagation model to 50 millimeters per hour.

Each type of propagation model object supports a different set of properties. For a full list of the properties and their descriptions for a propagation model type, see the associated object page.

Type of Propagation Model	Object Page
'freespace'	FreeSpace
'rain'	Rain
'gas'	Gas
'fog'	Fog
'close-in'	CloseIn
'longley-rice'	LongleyRice
'tirem'	TIREM
'raytracing'	RayTracing

Output Arguments

pm — Propagation model

FreeSpace object | Rain object | Gas object | Fog object | CloseIn object | ...

Propagation model, returned as a FreeSpace, Rain, Gas, Fog, CloseIn, LongleyRice, TIREM, or RayTracing object.

References

[1] Sun, Shu, Theodore S. Rappaport, Timothy A. Thomas, Amitava Ghosh, Huan C. Nguyen, Istvan Z. Kovacs, Ignacio Rodriguez, Ozge Koymen, and Andrzej Partyka. “Investigation of Prediction Accuracy, Sensitivity, and Parameter Stability of Large-Scale Propagation Path Loss Models for 5G Wireless Communications.” IEEE Transactions on Vehicular Technology 65, no. 5 (May 2016): 2843–60. https://doi.org/10.1109/TVT.2016.2543139.

[2] International Telecommunications Union Radiocommunication Sector. Attenuation due to clouds and fog. Recommendation P.840-6. ITU-R, approved September 30, 2013. https://www.itu.int/rec/R-REC-P.840-6-201309-S/en.

[3] International Telecommunications Union Radiocommunication Sector. Specific attenuation model for rain for use in prediction methods. Recommendation P.838-3. ITU-R, approved March 8, 2005. https://www.itu.int/rec/R-REC-P.838-3-200503-I/en.

[4] Hufford, George A., Anita G. Longley, and William A.Kissick. A Guide to the Use of the ITS Irregular Terrain Model in the Area Prediction Mode. NTIA Report 82-100. National Telecommunications and Information Administration, April 1, 1982.

[5] Seybold, John S. Introduction to RF Propagation. Hoboken, N.J: Wiley, 2005.

[6] International Telecommunications Union Radiocommunication Sector. Attenuation by atmospheric gases. Recommendation P.676-11. ITU-R, approved September 30, 2016. https://www.itu.int/rec/R-REC-P.676-11-201609-S/en.

[7] International Telecommunications Union Radiocommunication Sector. Effects of building materials and structures on radiowave propagation above about 100MHz. Recommendation P.2040-1. ITU-R, approved July 29, 2015. https://www.itu.int/rec/R-REC-P.2040-1-201507-I/en.

[8] International Telecommunications Union Radiocommunication Sector. Electrical characteristics of the surface of the Earth. Recommendation P.527-5. ITU-R, approved August 14, 2019. https://www.itu.int/rec/R-REC-P.527-5-201908-I/en.

[9] Yun, Zhengqing, and Magdy F. Iskander. “Ray Tracing for Radio Propagation Modeling: Principles and Applications.” IEEE Access 3 (2015): 1089–1100. https://doi.org/10.1109/ACCESS.2015.2453991.

[10] Schaubach, K.R., N.J. Davis, and T.S. Rappaport. “A Ray Tracing Method for Predicting Path Loss and Delay Spread in Microcellular Environments.” In [1992 Proceedings] Vehicular Technology Society 42nd VTS Conference - Frontiers of Technology, 932–35. Denver, CO, USA: IEEE, 1992. https://doi.org/10.1109/VETEC.1992.245274.

Version History

Introduced in R2017b

R2022a: propagationModel('raytracing-image-method') syntax will be removed in a future release

Warns starting in R2022a

The propagationModel('raytracing-image-method') syntax will be removed in a future release.

Use the propagationModel('raytracing','Method','image') syntax to use the image ray tracing method. Alternatively, using the propagationModel('raytracing') syntax sets the ray tracing method to SBR.

R2021b: Default modeling method is shooting and bouncing rays method

Behavior changed in R2021b

Starting in R2021b, when you create a propagation model using the syntax propagationModel('raytracing'), MATLAB^® returns a RayTracing model with the Method value set to 'sbr' and two reflections (instead of 'image' and one reflection as in previous releases).

To create ray tracing propagation models that use the image method, use the syntax propagationModel('raytracing','Method','image').