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- frequency;
- height of receiver antenna;
- height of transmitter antenna;
- distance between transmitter and receiver antennas (in horizontal plane);
- environment factor (if relevant for the model).
This function is evaluated by calling a particular propagation model selected for the concerned path (VLT-VLR, ILT-ILR, ILT-VLR and ILT-VLT) in the scenario. The in-built SEAMCAT models do not take into account any path-specific topographic considerations (i.e. no terrain).
Guidance on selecting the propagation model
You can select any propagation model(s) depending on the scenario and purposes of your simulation, e.g. type of radio systems and environment considered in the scenario.
To aid in the selection process, the following table provides an indication of the application ranges and typical areas of suitability of the in-built propagation models in SEAMCAT:
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Testing the propagation model
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By default SEAMCAT assumes the height of local clutter to be 10 m for both RURAL and SUBURBAN environment and 20 m for URBAN environment. In SEAMCAT, you are given the option to define its own local clutter height, which may be then different from the above default values. Therefore, when using P.1546 model, it is very important to consider the height of receiver antenna with regards to the assumed height of local clutter.The figure below shows an example of how the median propagation loss calculated with P.1546 model would change depending on the height of receive antenna (h2), and how it compares with the corresponding Hata modelresults (the curves are for 600 MHz, 50% time, 50% locations, default local clutter setting in P.1546).
When the height of receiver antenna h2 in P.1546 is set to 1.5 m, which is much below the assumed height of local clutter (the default value of 10 dB was used in these simulations), then the propagation loss is much higher (by almost 20 dB) than the one generated with P.1546 for h2=10 m (i.e. when receiver antenna was set equal to the height of local clutter). In the latter case, the P.1546 losses are quite close to the results produced with Hata model, especially for shorter distances.The latest available version P.1546-1 (2003) had been implemented, which in particular contains revised definition of transmitter antenna height and some additional corrections, such as the correction for short urban/suburban paths.