Page 150 - Integrated Wireless Propagation Models

128 C h a p t e r T h r e e

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Coverage area

Tunnel

FIGURE 3.1.5.2.7 The importance of integrated attribute; morphology.

Some trees are taller than 30 ft and will have some impact on signal propagation, espe­
cially in situations where signals pass through a boundary from LOS to non-LOS.
A sudden change of signal strength can easily be from 10 to 20 dB.
Figure 3.1.5.2.7 shows the whole scenario of a radial path from the beginning at the
BTS to the end at the mobile with morphology. Immediately after exiting a tunnel, a
spike of signal strength is expected.

3 . 1 .5.2.3 Knife-Edge Diffraction As shown in Fig. 3.1.5.2.8, the edge h, which is gener­
ally used to calculate the shadow loss is replaced by H, which equals the sum of h and
the human-made structure height a. Also, the formula of calculating the diffraction loss
with morphology will be different.

Morphology

c
0
i
[jJ

Radial distance
FIGURE 3.1.5.2.8 The portance of integrated attribute/morphology with terrain.
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i