The total path loss is the sum of the following individual components.
(3.71) LTOT LFS multiple screen diffraction diffraction to the ground level
1.5 GHz fc 2 GHz
30 m hBS 200 m
1 m hMS 10 m
1 km d 20 km
a(hMS) [44.9 6.55 # log(hBS)] # log(d) CM
Lurban
ModHata(dB) 46.3 33.9 # log( fc) 13.82 # log(hBS)
Lrural
Hata (dB) Lurban
Hata (dB) 4.78 # [log( fc)]2 18.33 # log( fc) 40.98
Lsuburban
Hata (dB) Lurban
Hata (dB) 2 cloga fc
28bd2
5.4
a(hMS) c8.29 # (log(1.54 # hMS)2 1.1 dB fc 300 MHz
3.2 # (log(11.75 # hMS)2 4.97 dB fc 300 MHz
a(hMS) (1.1 # log( fc) 0.7) # hMS (1.56 # log( fc) 0.8)
152 CHAPTER THREE
Next we discuss each component separately. The free space loss is given as
(3.72)
The multiple screen diffraction is the reduction in the rooftop signal at the building row just before
the subscriber as a result of the propagation past the previous rows of buildings.
(3.73)
(3.74)
And the diffraction to the ground level is the reduction due to the diffraction of the rooftop fields
down to the street level.
(3.75)
and (3.76)
The combined path loss is given as
(3.77)
Note the overall distance exponent is 3.8, which is remarkably close to the range of values typically
chosen between 3 and 4.
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