CONTENTS

Recommendation ITU-R P.452-18
Policy on Intellectual Property Right (IPR)
 1     Introduction
 2     Interference propagation mechanisms
 3     Clear-air interference prediction
        3.1     General comments
        3.2     Deriving a prediction
                  3.2.1     Outline of the procedure
 4     Clear-air propagation models
        4.1     Line-of-sight propagation (including short-term effects)
        4.2     Diffraction
                  4.2.1     The Bullington part of the diffraction calculation
                  4.2.2     Spherical-Earth diffraction loss
                  4.2.3     Complete ‘delta-Bullington’ diffraction loss model
                  4.2.4     The diffraction loss not exceeded for p% of the time
        4.3     Tropospheric scatter
        4.4     Ducting/layer reflection
        4.5     The overall prediction
        4.6     Calculation of transmission loss
 5     Hydrometeor-scatter interference prediction
        5.1     Theoretical basis of transmission loss due to hydrometeor scatter
        5.2     The model input parameters
                  5.2.1     Link geometric parameters
        5.3     Steps of applying the hydrometeor scatter algorithm
                  5.3.2     Step 2: Constructing a local raindrop bi-static cross section
                  5.3.3     Step 3: Constructing hydrometeor scatter geometry
                  5.3.4     Step 4: Constructing the scattering transfer function elements
                  5.3.5     Step 5: Integration of the scatter transfer function
                  5.3.6     Tables for section 5.3.1.2
                  5.3.7     Tables for section 5.3.2
Attachment 1 to Annex 1  Radio-meteorological data required for the clear-air  prediction procedure
 1     Introduction
 2     Maps of vertical variation of radio refractivity data and surface refractivity
Attachment 2 to Annex 1  Path profile analysis
 1     Introduction
 2     Construction of path profile
 3     Path length
 4     Path classification
 5     Derivation of parameters from the path profile
        5.1     Trans-horizon paths and LoS paths
                  5.1.1     Interfering antenna horizon elevation angle, θt
                  5.1.2     Interfering antenna horizon distance, dlt
                  5.1.3     Interfered-with antenna horizon elevation angle, θr
                  5.1.4     Interfered-with antenna horizon distance, dlr
                  5.1.5     Angular distance θ (mrad)
                  5.1.6     “Smooth-Earth” model and effective antenna heights
Attachment 3 to Annex 1  An approximation to the inverse cumulative normal distribution function for x £ 0.5