Application
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Propagation of electromagnetic waves in areas with a low density of
buildings depends mainly on the topography
and the land usage (clutter).
The vector data of the buildings
must not be considered in such scenarios.
A wide selection of propagation models
for these scenarios based on topography
and land usage (clutter) are
available in the PRO-R module
of ProMan. As these models
are very flexible they can also be used where no vector building data is
available in urban scenarios.
Generally the usage of topography and land usage without any further
vector building data is recommended if the transmitting antenna
(basestation) is located on a hill (or very tall building/mast) and
if the propagation in the vertical plane between Tx and Rx is
dominating.
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A
typical propagation scenario where
topography
and land usage
should
be considerd
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Propagation Models
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WinProp offers a wide variety of propagation
models for scenarios based on topography and land usage.
More information about the prediction models for these scenarios can be
found on the Propagation Page.
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Sample prediction
with a prediction
model.
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Databases: Topography and Clutter (Land Usage)
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The topography of the scenario
has a very strong influence on the
propagation of the electromagnetic waves. Therefore a detailed
topographical database is mandatory for the propagation models.
Additionally to the topography, the land
usage (water, roads,
buildings, forest,...) influences the propagation of electromagnetic
waves. Therefore land usage (clutter) databases can be used optionally
to
improve the accuracy of the path loss predictions.
Clutter databases
should have the same or even a finer resolution as the topographical
database.
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Topographical
database of
the Grand Canyon
(USA).
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In ProMan's PRO-R module the
user can define frequency dependent
losses for each clutter class - these clutter dependent losses can be
calibrated automatically with measurements. Besides these frequency
depending losses also the height of the objects in each clutter class
can be defined by the user (this is important for the Knife-Edge Diffrcation model).
The clutter classes can
also be used to control the selection of propagation models (e.g.
selection of submodels of Hata-Okumura
model) and the electrical
properties of the ground can be defined for each clutter class to
improve the accuracy of the ground reflected ray in the deterministic
two ray model.
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