comm.Ray
Create RF propagation ray
Description
A comm.Ray object contains the properties of an RF
propagation ray. The object contains the geometric and electromagnetic information of a radio
wave (approximated as a ray) that propagates from one point to another point.
Creation
Typically you create comm.Ray objects by using the raytrace function.
Description
ray = comm.Ray
ray = comm.Ray(Name=Value)comm.Ray(CoordinateSystem="geographic",TransmitterLocation=[40.730610;-73.935242;0])
creates a ray referenced to a geographic coordinate system with a transmitter located in
New York City.
Properties
Object Functions
plot (rays) | Display RF propagation rays in Site Viewer |
Examples
Perform ray tracing in Hong Kong and return the rays in comm.Ray objects. The comm.Ray objects contain geometric and electromagnetic information for propagation paths between the transmitter and receiver sites.
Launch Site Viewer with buildings in Hong Kong. For more information about the OpenStreetMap® file, see [1].
viewer = siteviewer(Buildings="hongkong.osm");
Create transmitter and receiver sites.
tx = txsite(Latitude=22.2789,Longitude=114.1625, ... AntennaHeight=10,TransmitterPower=5, ... TransmitterFrequency=28e9); rx = rxsite(Latitude=22.2799,Longitude=114.1617, ... AntennaHeight=1);
Create a ray tracing propagation model, which MATLAB® represents using a RayTracing object. Configure the model to find paths with up to 3 surface reflections and up to 1 edge diffraction. By default, the model uses the shooting and bouncing rays (SBR) method.
pm = propagationModel("raytracing",MaxNumReflections=3,MaxNumDiffractions=1);Perform the ray tracing analysis. The raytrace function returns a cell array containing the comm.Ray objects. By default, ray tracing models discard rays that are more than 40 decibels weaker than the strongest path.
rays = raytrace(tx,rx,pm)
rays = 1×1 cell array
{1×15 comm.Ray}
Display the properties of the first comm.Ray object. The value of the LineOfSight property is 1, and value of the NumInteractions property is 0. This combination indicates that the ray defines a line-of-sight path.
rays{1}(1)ans =
Ray with properties:
PathSpecification: 'Locations'
CoordinateSystem: 'Geographic'
TransmitterLocation: [3×1 double]
ReceiverLocation: [3×1 double]
LineOfSight: 1
Frequency: 2.8000e+10
PathLossSource: 'Custom'
PathLoss: 104.2656
PhaseShift: 4.6406
Read-only properties:
PropagationDelay: 4.6442e-07
PropagationDistance: 139.2294
AngleOfDeparture: [2×1 double]
AngleOfArrival: [2×1 double]
NumInteractions: 0
Display the properties of the third comm.Ray object. The value of the LineOfSight property is 0, and the value of the NumInteractions property is 2. This combination indicates that the ray defines a path with two interface interactions.
rays{1}(3)ans =
Ray with properties:
PathSpecification: 'Locations'
CoordinateSystem: 'Geographic'
TransmitterLocation: [3×1 double]
ReceiverLocation: [3×1 double]
LineOfSight: 0
Interactions: [1×2 struct]
Frequency: 2.8000e+10
PathLossSource: 'Custom'
PathLoss: 142.4192
PhaseShift: 0.7186
Read-only properties:
PropagationDelay: 8.3065e-07
PropagationDistance: 249.0217
AngleOfDeparture: [2×1 double]
AngleOfArrival: [2×1 double]
NumInteractions: 2
Display the interaction types, locations, and materials by querying the Interactions property.
rays{1}(3).Interactions(1)ans = struct with fields:
Type: 'Diffraction'
Location: [3×1 double]
MaterialName: "concrete"
rays{1}(3).Interactions(2)ans = struct with fields:
Type: 'Reflection'
Location: [3×1 double]
MaterialName: "concrete"
Visualize the sites and the ray tracing paths.
show(tx)
show(rx)
plot(rays{1})
Appendix
[1] The OpenStreetMap file is downloaded 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/.
Perform ray tracing in Chicago and return the rays in comm.Ray objects. Then, display the rays without performing the ray tracing analysis again.
Launch Site Viewer with buildings in Chicago. For more information about the OpenStreetMap® file, see [1].
viewer = siteviewer(Buildings="chicago.osm");
Create a transmitter site on one building and a receiver site on another building. Show the line-of-sight path between the sites using the los function.
tx = txsite(Latitude=41.8800, ... Longitude=-87.6295, ... TransmitterFrequency=2.5e9); rx = rxsite(Latitude=41.881352, ... Longitude=-87.629771, ... AntennaHeight=30); los(tx,rx)
Create a ray tracing propagation model, which MATLAB® represents using a RayTracing object. By default, the model uses the SBR method and calculates propagation paths with up to two reflections.
pm = propagationModel("raytracing");Perform the ray tracing analysis. The raytrace function returns a cell array containing the comm.Ray objects.
rays = raytrace(tx,rx,pm)
rays = 1×1 cell array
{1×3 comm.Ray}
View the properties of the first ray object.
rays{1}(1)ans =
Ray with properties:
PathSpecification: 'Locations'
CoordinateSystem: 'Geographic'
TransmitterLocation: [3×1 double]
ReceiverLocation: [3×1 double]
LineOfSight: 0
Interactions: [1×1 struct]
Frequency: 2.5000e+09
PathLossSource: 'Custom'
PathLoss: 92.7686
PhaseShift: 1.2945
Read-only properties:
PropagationDelay: 5.7088e-07
PropagationDistance: 171.1462
AngleOfDeparture: [2×1 double]
AngleOfArrival: [2×1 double]
NumInteractions: 1
Close Site Viewer.
close(viewer)
Create another Site Viewer with the same buildings, transmitter site, and receiver site. Then, display the propagation paths. Alternatively, you can plot individual paths by specifying a single ray object, for example rays{1}(2).
siteviewer(Buildings="chicago.osm"); show(tx) show(rx) plot(rays{1},Type="power", ... TransmitterSite=tx,ReceiverSite=rx)
Appendix
[1] The OpenStreetMap file is downloaded 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/.
