Weissberger's model

Weissberger’s modified exponential decay model, or simply, Weissberger’s model, is a radio wave propagation model that estimates the path loss due to the presence of one or more trees in a point-to-point telecommunication link. This model belongs to the category Foliage or Vegetation models.

Applicable to/under conditions

* This model is applicable to the cases of line of sight propagation. Example is microwave transmission.

* This model is only applicable when there is an obstruction made by some foliage in the link. i.e. In between the transmitter and receiver.

* This model is ideal for application in the situation where the LOS path is blocked by dense, dry and leafy trees.

Coverage

Frequency: 230 MHz to 95 GHzRadio propagation in cellular networks, N. Blaunstein]

Depth of Foliage: up to 400 m

History

Formulated in 1982, this model is a development of the ITU Model for Exponential Decay (MED).

Mathematical formulation

Weissberger’s model is formally expressed as

:

where,

"L" = The loss due to foliage. Unit: decibels (dB)

"f" = The transmission frequency. Unit: gigahertz (GHz)

"d" = The depth of foliage ‘’’along’’’ the path. Unit: meters (m)

Points to note

* The equation is scaled for frequency specified in GHz range.
* Depth of foliage must be specified in meters (m).

Limitations

*This model is significant for frequency range 230 MHz to 95 GHz only, as pointed out by Blaunstein.

*This model does not define the operation if the depth of vegetation is more than 400 m.

*This model predicts the loss due to foliage. The path loss must be calculated with inclusion of the free space loss. [Introduction to RF propagation, John S. Seybold]

References

Further reading

* "Introduction to RF Propagation," John S. Seybold, 2005, John Wiley and Sons.
* "Radio Propagation in Cellular Networks," N. Blaunstein, 2000, Artech House
* "The Mobile Radio Propagation Channel," J. D. Parsons, 2000, Wiley
* cite paper
author = Mark A. Weissberger
title = An initial critical summary of models for predicting the attenuation of radio waves by trees
date = 1982
url =http://stinet.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA118343
format = PDF
accessdate = 2007-02-21

ee also

* Fresnel zone
* Radio propagation model

External links