Early ITU model

The ITU vegetation model is a radio propagation model that estimates the path loss encountered due to the presence of one or more trees inside a point to point telecommunication link. The predictions found from this model is congruent to those found from Weissberger’s modified exponential decay model in low frequencies.

History[edit]

The CCIR, predecessor of ITU, adopted this model in the late 1986.

This model is applicable on the situations where the telecommunication link has some obstructions made by trees along its way
This model is suitable for point-to-point microwave links that has a vegetation in their path.
Typical application of this model is to predict the path loss for microwave links.

Frequency: Not specified

Depth of Foliage: Not specified

The model is formulated as:

$L=0.2\,f^{0.3}\,d^{0.6}$

Where

L = The path loss. Unit: decibel (dB)

f = The frequency of transmission. Unit: megahertz (MHz)

d = The depth of foliage along the link: Unit: meter (m)

This equation is scaled for frequency specified in megahertz (MHz).

The depth of foliage must be in the units of meters.

The results of this model gets impractical at high frequencies.

v t e Radio frequency propagation models
Free space	Free-space path loss Friis transmission equation Dipole field strength in free space
Terrain	ITU terrain model Egli model Longley–Rice Irregular Terrain Model (ITM) Two-ray ground-reflection model
Foliage	Weissberger's model Early ITU model One woodland terminal model Single vegetative obstruction model
Urban	Okumura model Hata model COST Hata model Young model Six-rays model Ten-rays model
Indoor	ITU model for indoor attenuation Log-distance path loss model
Other	VOACAP (HF) Area-to-area Lee model (900 MHz) Point-to-point Lee model (900 MHz) Longley–Rice model (20 MHz - 20 GHz)