Page 228 - Integrated Wireless Propagation Models

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

The received signal strength under flat terrain is as follows:

P , = F: G , - L s + G , (4.2.3.1.1)
+
w
where P, = received signal strength, P, = transmitted power, G = transmitter antenna
,
=
gain, L s l oss under LOS, and G = r eceiving antenna gain. L s is computed as follows:
w
w
,
First, calculate the near-in distance (see Sec. 4.2. . 1 ) from the following equation:
1
4 h
d - � 2 (4.2.3.1.2)
I - A
where d = near-in distance (Eq. [4.2.1.1.4]), h = transmitter height, h = receiver height,
1
2
1
and = Wavelength. If the mobile's position at distance d is within the near-in area, d � d f'
A
47td
L s = 20 log T (4.2.3.1.3)
w
4nd 1 d
-
L s 20 log - - y log d ( 4.2.3.1.4)
_
w - A
f
where y = slope and d = distance between transmitter and receiver.
Considering Figure 4.2.3.1.2 under true terrain conditions, taking a case of terrain
sloping up the terrain contour does have an effect on the signal received by the mobile.
There is an effective antenna gain that is due to the position of the mobile on an elevated
slope. The signal received under this condition would be
( 4.2.3.1.5)
The effective antenna gain G is given as
,ff"
h
Ge = 20 log ft (4.2.3.1.6)
ff a
where at the base station antenna h , = effective height, and ha = actual height.
Equation (4.2.3.1.5) is the same as used in Lee macrocell prediction model (see Sec. 3.1.2.4) .

. . ....... Y
FIGURE 4.2.3.1.2 LOS.