# 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.

## 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.[2]

## See also

## References

- Radio propagation in cellular networks, N. Blaunstein
- Introduction to RF propagation, John S. Seybold

## 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- Mark A. Weissberger (1982). "An initial critical summary of models for predicting the attenuation of radio waves by trees" (PDF). Retrieved 2012-02-01. Cite journal requires
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