With certain building environment assumptions such as hMS 1.5 m, hBS 30 m, b 60 m,
hroof 10 m we can write an approximation as
(3.78)
(3.79)
This close agreement supports the assumption that propagation takes place over the buildings, with
diffraction from the rooftop to the ground level. We will make various comparisons about measurements
published across the world. Their details can be found in references: [98??“123].
LHata 49.2 26.2 # log ( fc) 35.2 # log(R)
LTOT 53.7 21 # log( fc) 3.8 # log(R)
LTOT a l
4pRb2
# (2.3474)2 # ca?„b
l d1.8
# l
2p2r
# a1
u
1
2p ub2
r 2(hroof hMS)2 x2 u a tanahroof hMS
l b
LDS
l
2p2r
# a1
u
1
2p ub2
a a tan chBS hroof
R d >
hBS hroof
R
LMSD (2.3474)2 # ca?„b
l d1.8
LFS c l
4pRd2
WIRELESS MULTIPATH CHANNEL 153
hBS
hroof
b
R
a
x
hBS
q
r
FIGURE 3.45 Mathematical propagation model.
First we present a summary of the published results for a microcell environment. We will define
microcells as those cells that have a radius of less than 1 km. In viewing the following microcell path loss
summary we can make a few observations (see Fig. 3.46). First we can see a large variation in the published
results mainly due to differences in countries, BS antenna height, MS antenna height, surrounding
154 CHAPTER THREE
Microcell Comparison
??“140
??“130
??“120
??“110
??“100
??“90
??“80
??“70
??“60
??“50
??“40
??“30
10 100 1000 10000
Distance (meters)
Path Loss (dB)
PL (London, 905 MHz)
PL (CA, 1.
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