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

WINNER D5.4 v. 1.4
break-points or the dual-slope behaviour could not be found in our measurements. However, this depends
most probably on the randomness of the practical situation: We have decided to take it as part of our rural
LOS model.
For the line of sight (LOS) conditions the measurements suggest the path-loss equations:
with the standard deviation s = 3.5 dB.
PL(d) = 44.6 + 21.5 log 10 (d) (5.63)
The model is based partly on our measurements and partly on the literature research, where we have
adopted the two ray model for distances higher than the break-point. For the LOS environment we get
then:
where d = distance
PL(d) = 44.6 + 21.5 log 10 (d), s = 3.5 dB, d d BP
The path losses behave very similarly at the two frequencies. As a matter of fact the mean behaviour is
very near free-space path-loss in LOS conditions. The formula above can be adapted for the frequencies
between 2000 and 6000 MHz by replacing the constant 44.6 by a factor
C(f c ) = 36.2 + 20 log 10 (f c /(2·10 9 )) (5.65)
Note that the LOS path-loss depends on antenna heights only through the break-point distance.
5.6.1.5.2 NLOS model
The NLOS model is based on our measurements which have been fitted to results found in the literature
research. The measured path-loss curve for the NLOS conditions has the equation
with s = 6.7 dB.
PL = 55.8 + 25.1 log 10 (d) (5.66)
This path-loss equation was measured for the BS antenna height 23 m and MS antenna height 1.7 m. This
equation will be compared to some theoretical path-loss curves. From the literature we found that mostly
the standard deviation was a little bit higher than 6.7. Because our measurement was limited, we decided
to use the value 8 dB for the standard deviation.
The formula (5.66) above can be adapted for the frequencies between 2000 and 6000 MHz by replacing
the constant 55.8 by a factor
C(f c ) = 46.9 + 20 log 10 (f c / (2·10 9 )) · 1.063 (5.67)
= 46.9 + 21.3 log 10 (f c / (2·10 9 ))
The constant 1.063 is based on our finding that the path loss difference in between 5.25 and 2.45 GHz for
NLOS conditions was about 2.5 dB higher than for free space, see paragraph 5.6.9.
After D5.3 the following equation was proposed for the D1 rural NLOS scenario path-loss by the WP5 to
other work-packages. This model is called. COST231-Hata model, originally for urban and suburban
environments. Slightly simplified it reads as
f
c
d
PL = 20log10 ( ) + [ 44.9 −6.55log10
( hBS
) ] log10
( ) −13.82log10
( hBS
) + 153. 39 (5.68)
2000
1000
where h BS is the height of the base station, f c is the centre-frequency (MHz), and d is the distance between
BS and MS (m).
This model and another well-known model, Erceg model 1, will be compared to the measured curve.
The modification of the BS antenna height is probably needed, because the environment of the
measurements is extremely flat. This can be compensated by adding 25 m to get an effective BS antenna
height that is greater in flat than in hilly environments.
Both models work equally well, if the BS antenna height is between, say, 10 and 100 m. For higher
antenna heights the curves begin to differ. According to the comparison, the modified COST231-Hata
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