Final report on link level and system level channel models - Winner

WINNER D5.4 v. 1.4
transmitter locations. The mean of the difference in one location was 12 dB and for the other 7 dB. In the
paper the path-loss model of [SMI+00] is found to fit the 1.9 GHz measurements on LOS streets. This
model is given by
PL
LOS
= e
−sr
λ
π
⎛
⎜
⎝ 4
2
⎞
⎟
⎠
1
e
r
t
1
+ R e
r
− jkrt − jkr n
m
2
(5.36)
where rt
is the line-of-sight path-length, R is the reflection coefficient of the road surface, and s is the
visibility factor. The variable r rm is the distance via reflection which is described as
r
(( h − h ) + ( h − h )) 2
2
rm = r +
(5.37)
b 0 m 0
where hb
and hm
are the base- and mobile-station heights and h0
is an effective surface height which is
different from zero due to reflections from cars and other obstacles. A best fit to the eighteen LOS streets
was found to be h
0 = 1.2m and s = 0.001. The RMS-error from this model in the eighteen LOS streets is
listed in a table. We notice that the breakpoint distance which is based on the clearance of the first Fresnel
zone with the parameters of the paper appears at such a short distance as 60 meters. The path-loss curve is
similar to a fourth-order slope beyond the breakpoint. We calculate an average the RMS error to be 7.1
dB from this data. The RMS-delay spread is <strong>report</strong>ed to be 15-20% lower at 5.9 GHz than at 1.9 GHz.
From inspection of the plots in the paper it appears that for LOS cases the delay-spread is 100-150 ns
quite independently of the frequency.
The paper [SMI+00] presents measurements with the transmitter at a height of 4 meters and the receiver
at 2.7 meters in a Japanese residential area at 3.5 GHz. The height of the buildings is on average eight
meters and is therefore higher than the antennas. If the ground level, h
0 , is set to zero then breakpoint
distance appears at 678 meters. The measurements up to 460 meters confirmed that free-space
propagation conditions existed. Delay-spreads never exceeded 200 ns for the LOS measurements. The
plotted power-delay profiles for LOS case seemed to show approximately the form of an exponential
decay plus a direct path.
The paper [MKA02] studies the impact of the traffic intensity in an urban area on the effective ground
level. In the paper the base-station height is 4meters and the mobile-station height 1.6 meter or 2.7 meter.
Measurements are done at 3.35, 8.45 and 15.75 GHz. The effective ground level is estimated to about 0.5
meter during night-time and 1.4meter during daytime. The paper also presents RMS-delay-spread values
versus path loss during night-time. From these figures we deduce that it is less than 200 ns at midnight
before the breakpoint distance. Beyond the breakpoint a 3.6 to 4.6 path-loss slope is observed. The
standard deviation around the mean value seems to be about ±5 dB before the breakpoint and ±10 dB
after the breakpoint. A formula for the delay-spread is fitted to the data as
s
[ ns] exp( β )
= , (5.38)
where β is 0.050 during day-time and 0.049 during night time. The sample-points used for the fitting of
this formula contain measurements at 3.35, 8.45 and 15.75 GHz. The paper does not state any variation
with frequency.
In [FBR+94] micro-cell measurements at 1900 MHz are analyzed for path loss and delay-spread with an
MS height of 1.7meter and base-station heights of 3.7, 8.5, and 13.3. A path-loss model is fitted where a
free-space propagation law is used up to the breakpoint and a 3rd or 4th order law is recommended
beyond that point, shadow fading estimates are in the range 7-8 dB. No effective street-level modelling is
used – maybe measurements were done when there was no traffic? An exponential dependence between
the path loss and delay-spread as in previous reference is also found – however this time the model
considers the maximum delay-spread. A visual inspection of the viewgraph of the paper seems to confirm
that typical delay-spreads obey the formula of [MKA02] given above.
In [FDS+94] measurements were done with the transmitter at 4meter height and the receiver on the top of
a Van at 2.5 meters. The measurements were done on Southampton University Campus at 1.8 GHz. The
results for LOS show a K-factor between 1 and 30 at range of up to the breakpoint. In contrast for the
NLOS measurements the K-factor is between 0 and 2.
In [KVV05] polarization is analyzed in various urban scenarios. The one, most similar to what is
considered here, is the urban micro-cell LOS case although the base-station is considerably more elevated
than what we are considering here and the mobile-station is less (BS height 10 meters, MS height 1.6
meter in the measurements). For this scenario an XPR of around 9 dB is obtained.
In [MIS01] directional measurements in an urban area with rotating antennas at 8.45 GHz are presented.
The base-station height is four or eight meters while the mobile-station height is 3.0 meters. The angle-
PL dB
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