coverage

The coverage function shows improved performance in scenes with buildings when you specify a RayTracing propagation model object as input.

For example, the following code creates a coverage map for an antenna site in an urban scene by using the coverage function and a RayTracing propagation model object created using the propagationModel function. The code that creates the coverage map is about 1.2x faster in R2024b than in R2024a.

function timingTest
    % Create Site Viewer and site
    sv = siteviewer(Buildings="chicago.osm");
    tx = txsite(Latitude=41.88,Longitude=-87.6295, ...
           TransmitterFrequency=2.5e9);
    
    % Create RayTracing object
    pm = propagationModel("raytracing", ...
        MaxNumReflections=1,MaxNumDiffractions=1);

    % Create coverage map
    t1 = tic;
    coverage(tx,pm)
    toc(t1)

    close(sv)
end

The approximate execution times are:

This code was timed on a Windows^® 11, AMD EPYC™ 74F3 24-Core Processor @ 3.19 GHz test system by calling the function timingTest.

You can download the OpenStreetMap file used in this example from https://www.openstreetmap.org, which provides access to crowd-sourced map data all over the world. The data is licensed under the Open Data Commons Open Database License (ODbL), https://opendatacommons.org/licenses/odbl/.

When calculating coverage using ray tracing models, the coverage function models materials using the methods and equations in International Telecommunication Union Recommendations (ITU-R) P.2040-3 [1] and ITU-R P.527-5 through ITU-R P.527-6 [2].

In previous releases, the function used ITU-R P.2040-1. As a result of these changes, the coverage function can return different values in R2024a compared to previous releases.

The coverage function performs ray tracing analysis with multiple materials in the same scene when you create the scene from an OpenStreetMap^® file or a geospatial table, and you specify the propmodel input argument as "raytracing" or a RayTracing propagation model object with its BuildingsMaterial property set to "auto" (the default).

The coverage function performs the ray tracing analysis using the materials stored in the file or table. If the file or table does not specify materials, or if the file or table specifies a material that the ray tracing analysis does not support, then the function uses concrete instead of the absent or unsupported material.

As a result, the coverage function can return different values in R2023b compared to previous releases. To avoid using the materials stored in the file or table, create a RayTracing object (by using the propagationModel function) and set its BuildingsMaterial property to "concrete". Then, use the object as input to the coverage function.

The coverage function shows improved performance with complex scenes when you specify a RayTracing propagation model object that uses the shooting and bouncing rays (SBR) method as input.

The time that MATLAB^® requires to perform ray tracing analysis depends on the scene and on the properties of the RayTracing object, such as the AngularSeparation, MaxNumDiffractions, MaxNumReflections, MaxAbsolutePathLoss, and MaxRelativePathLoss properties. In some cases, with moderate values of the MaxAbsolutePathLoss and MaxRelativePathLoss properties, the ray tracing analysis can be more than 2x faster in R2023b than in R2023a.

Ray tracing propagation models discard propagation paths based on path loss thresholds. By default, when you specify the propmodel input argument as "raytracing" or a RayTracing object, the propagation model discards paths that are more than 40 dB weaker than the strongest path.

As a result, the coverage function can return different values in R2023a compared to previous releases. To avoid discarding paths based on relative path loss thresholds, create a RayTracing object (by using the propagationModel function) and set its MaxRelativePathLoss property to Inf. Then, use the object as input to the coverage function.

When calculating coverage using ray tracing models, the coverage function now incorporates multipath interference by using a phasor sum. In previous releases, the function used a power sum. As a result, the calculations in R2022b are more accurate than in previous releases.

Starting in R2021b, when you use the coverage function and specify the propmodel argument or PropagationModel name-value argument as "raytracing", the function uses the shooting and bouncing rays (SBR) method and calculates up to two reflections. In previous releases, the coverage function uses the image method and calculates up to one reflection.

To display or compute coverage maps using the image method instead, create a propagation model by using the propagationModel function. Then, use the coverage function with the propagation model as input. This example shows how to update your code.

pm = propagationModel("raytracing","Method","image");
coverage(txs,pm)

For information about the SBR and image methods, see Choose a Propagation Model.

Starting in R2021b, all RF Propagation functions use the SBR method by default and calculate up to two reflections. For more information, see Default modeling method is shooting and bouncing rays method.