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Figure 3-17:
ITU multipath propagation model
Satellites above the Open Sky limit are not affected by multipath propagation.
Satellites in the Multipath Zone (elevation angle between Obstruction Limit and Open
Sky Limit) are considered LOS signals, but affected by multipath propagation. The ITU
model for LOS situation is used for these satellites.
For satellites in the Obstruction Zone (elevation angle below Obstruction Limit), the dir-
ect signal path may be obstructed, e.g., by a building. This is modelled by giving a probability
for an NLOS situation. With the given probability, the simulator classifies satellites as NLOS
and takes the ITU model for the NLOS situation into use. The NLOS situation changes only
when a satellite leaves the Obstruction Zone.
Note that, in addition to the two elevation limits mentioned above, the Elevation mask set-
ting applies to the simulation as normally.
The Propagation environment is defined by the environment type (open/rural/sub-
urban/ urban) and three parameters:
Open sky limit, Obstruction limit and NLOS probability.
Default values for the parameters in each environment type are given in the table below.
The Open environment type is the default, meaning that all satellites assume free-space
propagation.
Table 3-1:
Propagation environment type parameters
Environment Open sky limit Obstruction limit NLOS probability
Rural 20° 15° 0.1
70 User Manual GSG-5/6 Series Rev. 27
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