Page 246 - Integrated Wireless Propagation Models

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

used to verify the models as well as to understand the key issues that are to be
addressed in this section. From the measured data, we clearly understand the impact
of the nature and thus enhance the models so that the models interact among them­
selves and smoothly transition from one to another.
In this section, we will focus on the transition of models from microcell to macro­
1 1
cell. 7· 8 The microcell prediction can work closely with the concept of using multiple radio
radials. We have to ensure that the characteristics of microcell propagation are simulated
through the multiple radials in the database of the macrocell model.

I
3
4. . 1 The Algorithms for n tegrating the Two Models
The Lee model for microcell prediction has been enhanced to support this multiple
breakpoint macrocell propagation prediction model, as mentioned in Chap. 3. The
1-mile intercept is used as the final breakpoint of this multiple-breakpoint microcell
propagation model. Note that the symbol for distance is the Lee macrocell model uses
r, and the Lee microcell model uses d. It is for making a distinguishability between the
two groups of formulas.

A. The Lee Macrocell formula used for distances greater than 1 mile is

P, = P - y log(� J + Geffh + L0 +a for r > r 0 in dBm (4.3.l.la)
0
When the signal is obtained over a flat ground with a standard setting (a = 0), then

P, = P - y l og (� J for r > r 0 in dBm (4.3 l . l b)
.
0
where P = a power at r in dBm;
0
0
r = distance from the transmitter in meters;
r = distance measured in feet or meters (the default distance is 1 mile or 1.6 km);
0
y = macrocell slope in dB I dec;
Ge!Jh = effective height gain = 20 log (h/h) in dB, when in shadow Geffh = 0;
he = effective antennas height in meters\
h1 = height of base station antenna in meters;
L0 = shadow loss in dB if blocked (when in LOS, L0 = 0; and
a = standard adjustments in dB for those parameters having different values from
the standard set.
B. The received signal for the area within a radius of the near-in distance d is
1
expressed as
4nd
P, = P,, - 20 log ( ) + L0 + Geff1' + a in dBm for d s; d in dB (4.3.1.2a)
T 1
C. The radio signal received at the near-in distance is

in dBm (4.3.1.2b)