Page 108 - Integrated Wireless Propagation Models

86 C h a p t e r T w o

Buildings Buildings

Mobile

Buildings

wave

FIGURE 2.15.2 Defi i n g the street orientation angle.
n

ms
L d decreases for wider building separation (b). The quantities k a , k d , and k MHz determine
the dependence of loss on the distance (dkm) and the frequency (J MH J The term in the
formula for the multiscreen diffraction loss is given by

tlhb > 0
tlhb � 0 and dkm 2 0.5 (2.15.8)
!:J.hb � 0 and dkm < 0.5

This relation in Eq. (2.15.8) shows that there is a 54-dB diffraction loss if the base station
antenna is above the rooftops (tlhb > 0), but more than a 54-dB loss if it is below the rooftops.

5
Ill !_........___
""0 1---- �
-� /
rJ) �
rJ)
_Q 0 ............
c
0 /
�
c I
Q) -5
.§ /
'§
_J I
-10
0 1 0 20 30 40 50 60 70 80 90
<jl, angle of incidence in degree
FIGURE 2.15.3 Orientation loss versus angle of i n cidence.