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

WINNER D5.4 v. 1.4
model can be used from 100 m to 10 km, although originally the model has been defined for distances
greater than 1 km. The modified Erceg model 1 could be applied as well.
5.6.1.5.3 Unified model
For the overall path-loss in the D1 scenario we get from measurements the formula
PL(d) = 50.4 + 25.8 log 10 (d) (5.69)
The drawback of this model is that it is based on relatively few measurements. In addition the LOS
condition disappeared after quite a small distance from the BS. This depends e.g. on the fact that the BSs
were located slightly off the roads for practical reasons. Real BS:s would be located probably in more
beneficial way.
The unified model can be formed also by combining the LOS model and the NLOS model using the LOS
probability p LOS (d):
PL(d) = p LOS (d) PL LOS (d) + [1- p LOS (d)] PL NLOS (d) (5.70)
where d is the distance between MS and BS. p LOS will be defined in Section 5.6.1.5.4
The drawback of this model is that the p LOS used here is only theoretical one. However, it gives
reasonable results, and is used therefore as basis of comparison of our model and the models found in the
literature.
5.6.1.5.4 Probability of LOS model
Probability of LOS in the D1 scenario is proposed to be modelled with an exponential function
P LOS
d
( d)
= exp( − )
(5.71)
where d is the distance between the BS and the MS and d 0 is the constant defining the steepness of the
exponential decay.
Default value for d 0
is proposed to be 1 km. The reason for proposing this model is the following: It is
very near the model for LOS probability defined in [SCM] at small distances. In addition it does not go to
zero at the cell boundary, so that it can be used in the system-level modelling of interference.
5.6.1.5.5 Model comparison
In the figure below there are the measurement based PL curves obtained in the WINNER project
compared to some well-known PL models from the literature. In addition there is the free-space loss
curve. In the comparison the base station antenna height was 24.5 m; mobile antenna height was the
default value 1.7 m.
d 0
Figure 5.89: Comparison of channel models for a rural environment.
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