# Modified Free Space Model (MF)

The modified-free-space model analyzes the building concerning distances between walls and penetration losses of the walls, but the individual positions of the walls and their material properties are not considered.

This model computes the path loss similar to the free space loss with an adjustable
exponent and offset. Herewith it assumes that the excess path loss (in dB) is linearly
dependent on the distance with a specific attenuation coefficient *n*:

The modified-free-space model does not consider the walls of the building, thus no database
is required. With constant values for *n* and *l _{c}* the prediction
leads to field strength values decreasing in concentric circles around the transmitter.
According to this the prediction results are fairly inaccurate and only suited for a rough
estimation.

To calibrate this model with measurement data the exponent and the offset to be used for
this model can be specified by using the Settings button. For
line-of-sight to the transmitter, the values for *n* are in the range between 1.0 and
1.4, in non-line-of-sight scenarios values up to 2.0 are possible.