Early ITU Model

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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.

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[edit] History

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

[edit] Applicable to/under conditions

  • 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.

[edit] Coverage

Frequency: Not specified

Depth of Foliage: Not specified

[edit] Mathematical formulation

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)

[edit] Points to note

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

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

[edit] Limitations

The results of this model gets impractical at high frequencies.

[edit] Further reading

Introduction to RF Propagation, John S. Seybold, 2005, John Wiley and Sons.

[edit] See also