pathloss
Path loss of radio wave propagation
Description
Examples
Path Loss of Receiver In Heavy Rain
Create a transmitter site and a receiver site.
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 a propagation model for heavy rain. Then, calculate the path loss at the receiver site using the propagation model.
pm = propagationModel("rain",RainRate=50);
pl = pathloss(pm,rx,tx)
pl = 127.3208
Input Arguments
propmodel
— Propagation model
propagation model object
Propagation model, specified as a FreeSpace
, Rain
,
Gas
,
Fog
,
CloseIn
,
LongleyRice
, TIREM
, or RayTracing
object.
Create propagation models by using the propagationModel
function.
rx
— Receiver site
rxsite
object  array of rxsite
objects
Receiver site, specified as an rxsite
object or an array of rxsite
objects.
tx
— Transmitter site
txsite
object  array of txsite
objects
Transmitter site, specified as a txsite
object or an array txsite
objects.
NameValue Arguments
Specify optional pairs of arguments as
Name1=Value1,...,NameN=ValueN
, where Name
is
the argument name and Value
is the corresponding value.
Namevalue arguments must appear after other arguments, but the order of the
pairs does not matter.
Example: pathloss(propmodel,rx,tx,Map="none")
Before R2021a, use commas to separate each name and value, and enclose
Name
in quotes.
Example: pathloss(propmodel,rx,tx,"Map","none")
Map
— Map for visualization or surface data
siteviewer
object  triangulation
object  string scalar  character vector
Map for visualization or surface data, specified as a siteviewer
object, a triangulation
object, a string scalar, or a character vector.
Valid and default values depend on the coordinate system.
Coordinate System  Valid map values  Default map value 

"geographic" 


"cartesian" 


^{a} Alignment of boundaries and region labels are a presentation of the feature provided by the data vendors and do not imply endorsement by MathWorks^{®}. 
In most cases, if you specify this argument as a value other than a siteviewer
or
"none"
, then you must also specify an output argument.
Data Types: char
 string
Output Arguments
pl
— Path loss
scalar  MbyN cell array
Path loss, returned as a scalar or as an MbyN cell array, where each cell contains a row vector of path losses in decibels. M is the number of transmitter sites and N is the number of receiver sites.
The function computes the path loss along the shortest propagation paths through space by connecting the centers of the transmitters and receivers.
For terrain propagation models, the function computes path loss using a
terrain elevation profile that it creates from sample locations on the great
circle path between the transmitter and receiver. If
Map
is a siteviewer
object with
buildings specified, the function adjusts the elevation to include the
heights of the buildings.
info
— Information corresponding to each propagation path
MbyN structure array  MbyN cell array
Information corresponding to each propagation path, returned as an MbyN structure array or cell array.
For most propagation models,
info
is a structure array.For ray tracing propagation models,
info
is a cell array, where each cell contains a vector of structures.
The structures contain these fields:
PropagationDistance
— Total length of the propagation path, returned as a double scalar in meters.AngleOfDeparture
— Angle of departure of the signal from the transmitter site, returned as a 2by1 double vector of azimuth and elevation angles in degrees.AngleOfArrival
— Angle of arrival of the signal at the receiver site, returned as a 2by1 double vector of azimuth and elevation angles in degrees.NumReflections
— Number of reflections along the propagation path, returned as a nonnegative integer. This field and value is applicable only for ray tracing propagation models.NumDiffractions
— Number of diffractions along the propagation path, returned as0
,1
, or2
. This field and value is applicable only for ray tracing propagation models.
The angle values in the structure depend on
CoordinateSystem
.
When
CoordinateSystem
is"geographic"
, the angle values are defined using the local eastnorthup coordinate system of the antenna. The azimuth angle is measured from east.When
CoordinateSystem
is"cartesian"
, the angle values are defined using the global Cartesian coordinate system. The azimuth angle is measured from the global xaxis around the global zaxis.
The elevation angle is measured from the horizontal (or xy) plane to the xaxis of the antenna, in the range –90 to 90.
References
[1] International Telecommunications Union Radiocommunication Sector. Effects of Building Materials and Structures on Radiowave Propagation Above About 100MHz. Recommendation P.2040. ITUR, approved August 23, 2023. https://www.itu.int/rec/RRECP.2040/en.
[2] International Telecommunications Union Radiocommunication Sector. Electrical Characteristics of the Surface of the Earth. Recommendation P.527. ITUR, approved September 27, 2021. https://www.itu.int/rec/RRECP.527/en.
Version History
Introduced in R2017bR2024a: Ray tracing functions model materials using updated ITU recommendations
When calculating path loss using ray tracing models, the
pathloss
function models materials using the methods and
equations in International Telecommunication Union Recommendations (ITUR) P.20403
[1] and ITUR P.5275
through ITUR P.5276 [2].
In previous releases, the function used ITUR P.20401. As a result of these
changes, the pathloss
function can return different values
in R2024a compared to previous releases.
R2024a: Get number of diffractions along ray tracing propagation paths
When you specify propmodel
as a RayTracing
object, info
stores the number of diffractions along
propagation paths in the NumDiffractions
field.
R2023a: Ray tracing models discard paths based on path loss
Ray tracing propagation models discard propagation paths based on path loss
thresholds. By default, when you specify the propmodel
input
argument as a RayTracing
object, the propagation model discards paths that are more than 40 dB weaker than
the strongest path.
As a result, the pathloss
function can return different
values in R2023a compared to previous releases. To avoid discarding propagation
paths based on relative path loss thresholds, set the
MaxRelativePathLoss
property of the ray tracing object to
Inf
.
R2022b: Ray tracing models using SBR method find paths with exact geometric accuracy
Ray tracing models that find propagation paths by using the shooting and bouncing rays (SBR) method correct the results so that the geometric accuracy of each path is exact, using singleprecision floatingpoint computations. In previous releases, the paths have approximate geometric accuracy.
As a result, when you use a ray tracing model as input to the
pathloss
function, the function can return different
results than in previous releases.
See Also
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