Wireless Network Design: Optimization Models and Solution ...

3 Channel Models for Wireless Communication Systems 51
for large cities:
for small cities:
Typical sub-urban
Rural area
a(hm) = 8.29(log 10 (1.54hm)) 2 − 1.1 for fc ≤ 200MHz (3.3)
a(hm) = 3.2(log 10 (11.75hm)) 2 − 4.97 for fc ≥ 400MHz (3.4)
a(hm) = (1.1log 10 ( fc) − 0.7)hm − (1.56log 10 ( fc) − 0.8) (3.5)
PL(dB) = 69.55 + 26.16log 10 fc
= (44.9 − 6.55log 10 ∆hb)log10d − 13.82log 10 hb
− a(hm)2(log 10 ( fc/28)) 2 − 5.4. (3.6)
PL(dB) = 69.55 + 26.16log 10 fc
= (44.9 − 6.55log 10 hb)log10d − 13.82log 10 hb
−a(hm) − 4.78(log 10 fc) 2 + 18.33log 10 ( fc) − 40.94. (3.7)
AT&T Bell Labs had made extensive measurements in the 1.9 GHz frequency
band for an outdoor fixed wireless system. For a given close-in distance d0, the
median path loss (PL in dB) is given by
PLa = A + 10γ log 10 (d/d0) + s f ord > d0, (3.8)
where A = 20log 10 (4πd0/λ),λ being the wavelength in meters, s is the shadow
fade margin, γ is the path-loss exponent with γ = (abhb + c/hb) for hb between 10
m and 80 m d0 = 100m and a,b,c are constants which depend on the terrain as given
in Table 3.1. The shadowing margin, s takes a value between 8.2 dB and 10.6 dB
Table 3.1 Values of a,b,c for different terrains
Model parameter Terrain Type A Terrain Type B Terrain Type C
a 4.6 4 3.6
b 0.0075 0.0065 0.005
c 12.6 17.1 20
depending on the terrain.
The above path loss model is for receive antenna heights close to 2 m. In order
to use the model for other frequencies and for receive antenna heights between 2 m
and 10 m, several experiments were conducted at Stanford University and correction