Propagation Models

Introduction

Propagation models allows you to predict the propagation and attenuation of radio signals as the signal travels through the environment. You can use the propagationModel function to simulate different models and determine the range and pathloss of radio signals in these simulated models.

Basic, Urban, Terrain and Multipath

Basic propagation models predict path loss as a function of distance between sites and assume line-of-sight (LOS) conditions, disregarding the curvature of the Earth, terrain, or other obstacles.

Urban propagation models also predict path loss as a function of distance but use empirical models that are derived from measurements in non-line-of-sight (NLOS) conditions..

Terrain propagation models such as Longley-Rice and Terrain Integrated Rough Earth Model™ (TIREM™) assumes that propagation occurs over a slice of terrain between two points. For both these models, you can calculate the point to point path loss between sites over irregular terrain including buildings. The path loss is calculated from free space loss, diffraction over obstacles and around Earth, ground reflection, refraction through atmosphere, and tropospheric scatter. The models combine physics with empirical data to provide path loss estimates.

Multipath propagation models use ray tracing techniques to predict path loss for multiple propagation paths that are computed from 3-D environment geometry. Electromagnetic analysis is applied to determine polarization changes and path loss due to rays interacting with surfaces.. The models support both 3-D outdoor and indoor environments.

Propagation Models

Model	Description	Frequency	Type	Combinations	Limitations
freespace	Ideal propagation model with clear line of sight between transmitter and receiver.		Basic	Can be combined with rain, fog, and gas propagation models.	Assumes line of sight
rain	Propagation of a radio wave signal and its path loss in rain.	1 to 1000 GHz	Basic	Can be combined with any other propagation model	Assumes line of sight.
gas	Propagation of radio wave signal and its path loss due to oxygen and water vapor.	1 to 1000 GHz	Basic	Can be combined with any other propagation model	Assumes line of sight
fog	Propagation of the radio wave signal and its path loss in cloud and fog.	10 to 1000 GHz	Basic	Can be combined with any other propagation model	Assumes line of sight
close-in	Propagation of signals in urban macro cell scenarios.		Urban	Can be combined with rain, fog, and gas propagation models.	—
longley-rice	Also known as Irregular Terrain Model (ITM). You can use this model to calculate point to point path loss between sites over irregular terrain, including buildings.	20 MHz to 20 GHz	Terrain	Can be combined with rain, fog, and gas.	Antenna height minimum is 0.5 m and maximum is 3000 m.
tirem	Terrain Integrated Rough Earth Model. Propagation model to calculate point to point path loss between sites.	1 MHz to 1000 GHz	Terrain	Can be combined with rain, fog, and gas.	Requires access to external TIREM library. Antenna height maximum is 30000 m.
raytracing-image-method	Multipath propagation model using ray trace analysis to compute propagation paths and corresponding path losses	100 MHz to 100 GHz	Multipath	Can be combined with rain, fog, and gas.	Does not include effects from refraction, diffraction, and scattering.