Page 274 - Integrated Wireless Propagation Models

252 C h a p t e r F o u r

-1 + 0.354<p for 0° � <p < 35°
0
2.5 + 0.075( <p-35) for 35° � <p < 55° (4.5.5.3.1.4)
4.0- 0 .114(<p-35) for 55° � <p < 90°

where

( 4.5.5.3. . 5)
1
L0,; is the street orientation correction factor, which takes into account the effect of
rooftop-to-street diffraction into streets that are not perpendicular to the direction of
[
propagation (see Fig. 4.5.5.3.1.1 b ); i s the incidence angle, w is the width of the street,
<p
]
and h, is the building height, as shown in Fig. 4.5.5.3.1.1(a).
Because the signal propagates passing over the rows of buildings, the multiple­
screen diffraction loss L d depends on the BS antenna height relative to the building
ms
heights h , and on the incidence angle <p. A criterion for grazing incidence is the "settled
field distance," d,:
(4.5.5.3.1.6)

where

(4.5.5.3.1.7)

For the calculation of L d for the distance l > ds, and, more accurately, when l >> ds,
ms
( 4.5.5.3. . 8)
1
where

for hb > h,
(4.5.5.3.1.9)
for hb � h,

L lr is a loss term that depends on the BS height:
bs
1 54 for hb > h,

-
Ka - 54- 0 .8�hb for hb � h, and d :::0: 500 m (4.5.5.3.1.10)
54- 1 .6Mb �000 for hb � h, and d < 500 m

18 for hb > h,
1 15 h,
Kd = 8 - Mb (4.5.5.3. . 11)
1
1