# Model_UrbanIRT

## Detailed Description

Model_UrbanIRT: Parameter for urban IRT model. See This structure is used for the definition of the parameters for the Intelligent Ray Tracing Model. The structure can be passed to the OutdoorPlugIn_ComputePrediction function but this is optional. It can be initialized with default values by using WinProp_Structure_Init_Model_UrbanIRT(). Determination of Diffraction Loss using the Empirical Interaction Model If the empirical interaction model is turned on (DiffractionModel = 'e') for the determination of the diffraction loss the following parameters are considered:
• LossDiffractionMin (LInc,min)
• LossDiffractionMax (LInc,max)
• LossDiffractionOut (LDiff)
For the empirical diffraction model the total loss of the diffracted rays is computed depending on the angles Phi and Phi' using the following relations indicated in the next figures: The empirical diffraction model computes the total diffraction loss in a two step approach based on the three parameters LInc,min, LInc,max and LDiff. In the first step the loss depending on the angle of incidence is determined (see left figure above). For this purpose the first two parameters LInc,min and LInc,max are evaluated. The corresponding loss increases with decreasing angle of incidence (i.e. increasing grazing incidence). Based on this first result the second curve (shown in the right figure above) is evaluated, leading to the total diffraction loss. Basically the diffraction loss increases with increasing interaction angle. However for a difference of 180 degrees, the total diffraction loss is fixed to 6 dB as in this special case the incident wave propagates straight forward while half of the space is shadowed according to the given obstacle. Therefore the range of possible total diffraction losses is given by [6 dB; LInc,max + LDiff]. The given angle dependence is derived from the uniform diffraction theory (UTD) by the evaluation of measurements with different materials (brick, concrete) in an anechoic chamber and can be varied with the parameters LInc,min, LInc,max and LDiff within appropriate limits.

## Field Documentation

DefaultMaterial
INTERFACE_MATERIAL Model_UrbanIRT::DefaultMaterial
GroundMaterial
INTERFACE_MATERIAL Model_UrbanIRT::GroundMaterial
BreakpointExponentBefore
double Model_UrbanIRT::BreakpointExponentBefore
Path Loss Exponent before breakpoint for NLOS areas.
BreakpointExponentAfter
double Model_UrbanIRT::BreakpointExponentAfter
Path Loss Exponent after breakpoint for NLOS areas.
BreakpointExponentBeforeLOS
double Model_UrbanIRT::BreakpointExponentBeforeLOS
Path Loss Exponent before breakpoint for LOS areas.
BreakpointExponentAfterLOS
double Model_UrbanIRT::BreakpointExponentAfterLOS
Path Loss Exponent after breakpoint for LOS areas.
BreakpointExponentSat
double Model_UrbanIRT::BreakpointExponentSat
Path Loss Exponent for a satellite transmitter.
PostProcessingMode
unsigned char Model_UrbanIRT::PostProcessingMode
Post-processing mode
• 0 = none
• 2 = KE (Knife edge)
Postprocessing
unsigned char Model_UrbanIRT::Postprocessing
Boolean to enable/disable post-processing with Knife edge model
• true = enabled
• false = disabled
DiffractionModel
char Model_UrbanIRT::DiffractionModel
Interaction model for IRT prediction model
• 'g' = fresnel & GTD/UTD
• 'e' = empirical interaction model
MaxReflections
char Model_UrbanIRT::MaxReflections
Maximum number of reflections
MaxDiffractions
char Model_UrbanIRT::MaxDiffractions
Maximum number of diffractions
MaxScatterings
char Model_UrbanIRT::MaxScatterings
Maximum number of scatterings
MaxSumReflDiff
char Model_UrbanIRT::MaxSumReflDiff
Maximum number of reflections + diffractions + scatterings.
GroundReflection
unsigned char Model_UrbanIRT::GroundReflection
Boolean to enable/disable ground reflection
• true = enabled
• false = disabled
AngularTolerance
double Model_UrbanIRT::AngularTolerance
Max. angular tolerance for ground reflection.
RaysPostProcessSRT
unsigned char Model_UrbanIRT::RaysPostProcessSRT
Boolean to enable/disable postprocessing of IRT rays with SRT
• true = enabled
• false = disabled
KE_Interactions
short Model_UrbanIRT::KE_Interactions
Max. number of interactions for Knife-Edge Model (if postprocessing with Knife-Edge Model is enabled).
KE_DiffractionLossOffset
double Model_UrbanIRT::KE_DiffractionLossOffset
Offset (dB) for Knife-Edge diffraction computation (if postprocessing with Knife-Edge Model is enabled).
KE_DiffractionLossAngle
double Model_UrbanIRT::KE_DiffractionLossAngle
Max. diffraction loss (dB) for Knife-Edge Model (if postprocessing with Knife-Edge Model is enabled).
KE_IRT_Interactions
int Model_UrbanIRT::KE_IRT_Interactions
1 to activate the combined KE & IRT interactions, 0 otherwise
FreeSpaceCancel
unsigned char Model_UrbanIRT::FreeSpaceCancel
Boolean to enable/disable abortion of computation of rays for one receiver pixel if free space loss is reached.
• true = enabled
• false = disabled
Superposition
unsigned char Model_UrbanIRT::Superposition
Mode for superposition of rays
• 0 = Uncorrelated
• 1 = Coherent (with phase)
COST_Transition
unsigned char Model_UrbanIRT::COST_Transition
Parameter for COST postprocessing. Please leave the default value.
COST_Trans_Min
double Model_UrbanIRT::COST_Trans_Min
Parameter for COST postprocessing. Please leave the default value.
COST_Trans_Max
double Model_UrbanIRT::COST_Trans_Max
Parameter for COST postprocessing. Please leave the default value.
Parameter for COST postprocessing. Please leave the default value.
Parameter for COST postprocessing. Please leave the default value.