Page 136 - Integrated Wireless Propagation Models

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

� aansition region
hP is negative,
v is between 0 and 1
FIGURE 3.1.2.4.3 Transition from shadow.

3.1.2.5 Adjustment Factor
The adjustment factor is the fifth component of the model as shown in Eq. (3 1 . 2.1). The
.
initial signal strength prediction at each point along the radial assumes a set of standard
conditions in making certain parameters at a base station transmit and at a mobile unit,
as follows:

P1 = b ase station output power = 10 W
h1 = b ase station antenna height = 100 ft ( -30.5 m)
h2 = mobile antenna height = 10 ft (-3.0 m)
g = b ase station antenna gain = 6 dBd
b
g = mobile antenna gain = 0 dBd
,
The fifth component of the Lee model in Eq. (3 1 . 2 . 1 ) also applies an adjustment
.
factor a for the signal strength prediction to compensate for the difference between
the standard conditions and the actual values of these parameters, which are defined
as follows:
�' = actual base station output power in watts
J; = actual base station antenna height in feet
h; = actual mobile antenna height (a default at 5 ft or . 5 ms)
1
g; = actual base station antenna gain in dBd
g:, = mobile antenna gain in dBd (a default at 0 dBd)
Note that the adjustment factor calculated here does not include an adjustment for
the standard base station antenna height. The standard base station antenna height is
used in determining the effective antenna height gain, whereas the actual base station
antenna height is used in determining diffraction loss.
The adjustment factor a is given by the following equation:

(3 1 . 2.5.1)
.
Because the actual mobile antenna height (h;) is always fixed at a half of the stan­
dard condition mobile antenna height (h 2 ), the adjustment for mobile antenna height is
10 log(0.5) = -3 dB. Also, because the mobile antenna gain is fixed a 0 dBd for both the
standard and the actual conditions, no adjustment is needed. Thus, the adjustment
factor needs only to adjust the actual base station output power and actual base station