Prediction of the
Mobile Radio Channel for Satellite Transmitters
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Transmitters
in ProMan must not be terrestrial. Also satellite transmitters can be considered.
Geostationary satellites are defined by their height (e.g. 36,000 km) and
their longitude. All LEOs and navigation satellites are described either
by the Two Line Element method or for the GPS satellites by the data provided
in the Almanac. Antenna gains for the satellite transmitters are considered in the path
loss predictions.
The satellite
radio transmission to the mobile terminal is strongly
affected by the variation of the received signal power
because of the presence of fading phenomena (slow fading due
to obstacles and fast fading due to multipath propagation).
Multipath propagation arises from signal reflection and
diffraction on obstacles. In satellite communications, the
received signal is usually the superposition of two
components: a main path and a summation of time-delayed
scattered paths. The occurence of these fading phenomena can
be predicted with ProMan by using specific wave propagation
models depending on the environment.
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Wave Propagation
Model for Wide Areas
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For wide areas
(corresponding to thousands of km^2) the empirical
prediction model according to DLR is used. This model
provides realistic and representative characterisations of
the land mobile satellite (LMS) radio channel based on the
evaluation of measurement data without taking into account a
specific transmitter-receiver configuration. The prediction
of the channel impulse response depends on the elevation of
the satellite and the land usage (clutter) at the receiver
location.
The following
clutter types are supported:
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urban
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sub-urban
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rural
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open
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 Satellite LOS Prediction based on clutter
map
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The wideband
channel model uses three submodels describing the different
parts of the impulse response depending on the echo delay:
direct path, near echos and far echos. The impulse response
of the satellite wideband channel is then superposed by a
sum of all echos.
ProMan needs
topographical
and
clutter databases to work with the DLR model.
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Wave Propagation
Model for Urban Areas
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The mobile radio
channel in urban environments is characterised by multipath
propagation. Dominant propagation mechanisms in these
scenarios are reflection, diffraction and shadowing by
discrete obstacles. With an ray optical approach it is
possible to consider these effects in a wave propagation
model. The urban ray-optical propagation model (IRT)
included in ProMan is used for the prediction of
ProMan needs
building (and
optionally topographical)
databases to work with the ray-optical prediction model
(IRT). |
 Satellite received power in Munich
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Modelling of the
Satellite to Indoor Channel
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The satellite to
indoor propagation channel is becoming of significant
importance (especially in L and S bands) as future satellite
mobile communication, broadcast and navigation systems (as
e.g. S-DMB and Galileo) are aiming at optimum performance in
all kind of environments, i.e. even in indoor scenarios. The
indoor scenarios are of special relevance for the
attractiveness of new MSS services in order to provide
ubiquitous coverage over all environments.
Of course also the penetration into buildings can be
computed with ProMan. To see the influence of the walls (and
their materials) inside the building and the neighboring
buildings, the ray-optical propagation models are used for
the prediction of
As basis for the
computation ProMan needs an
indoor database
(including the outdoor walls of the neighboring buildings)
which will be used as input for the ray-optical prediction
model. |
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Examples
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Here are some
sample predicitons presented. Please click on the pictures
to enlarge them.
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Predicted channel profile for satellite
transmitter
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Predicted channel profile (relative delays)
for hybrid network in
urban enviroment
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