Content Comparison

Anchor
A17.2 A17.2

This model describes the theoretical minimum propagation path loss achievable in free space conditions. This model is appropriate to use on paths were unobstructed direct-Line-of-Sight propagation could be expected (e.g. point-to-point fixed service links, links over short distances in open areas, etc). 

Image Removed 

...

Image Added

Anchor
F465F470F465 F470

Figure 465470: SEAMCAT Interface to the free space propagation model

...

For free space space  model the path loss is defined by:

 

...

Mathinline
body $L=32.4+10{{\log }_{10}}\left( {{\left( \frac{\left( {{h}_{tx}}-{{h}_{rx}} \right)}{1000} \right)}^{2}}+d_{{}}^{2} \right)+20{{\log }_{10}}f$

  (Eq. 189)

The variations correspond to the standard deviation variations.

Note: The Free space model allows the possibility to include some variations in the similar manner as it is done for all other built-in models. If user wants to use just the median theoretical value, the variations option should be disabled.

Figure 466 471 illustrates when the variation is disabled (i.e. no std).

Image Removed Image Added

Anchor
F466F471F466 F471

Figure 466471: Example of the vector events of the Free Space when Variation is disabled
(i.e. equivalent to σ = 0 dB) active (i.e. mean = 91.52 dB)

...

Figure 467 472 presents the Free Space when Variation is activated (std = σ = 2.5 dB). The value presented in Figure 466 471 and Figure 467 472 are extracted with the following parameters: f = 900 MHz, d =  1 km, h_tx = h_rx = 10 m.

Image Added

Anchor
F472 F472

  Example of Free Space results when the Variation (i.e. σ = 2.5 dB) is active 

(i.e. mean = 91.52 dB)