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

WINNER D5.4 v. 1.4
d = distance between BS and MS (m).
The original model is applicable up to 2 GHz, and in the distance range 1 – 20 km.
It should be noted that COST-231-Hata model is not a NLOS model, but it does not make difference
between the propagation conditions. However, at longer distances the propagation conditions are mostly
NLOS. So it can be applied for NLOS in spite of the afore-mentioned fact.
In reference [Zha02] the path-loss model for NLOS was
PL ( dB) = −27.8
+ 59log10 ( d)
, σ =1. 9 dB (5.51)
The parameters differ quite much from the values found out in this campaign. One reason is the hilly
terrain, the other could be the relatively small number of routes measured.
One interesting empirical channel model for suburban environment is [Erc99]. The suburban environment
is divided to three sub-environments according to the tree density and the height variation of the
environment. One of these environments could well be applied to the rural environment. This model is
created for 1. 9 GHz. With the same reasoning as afore it can be also extended to 5 GHz. The model is
PL = 20 log10 (4p 100/?) + 10 (a – b hBS + c/hBS) log10 (d/100) (5.52)
where the parameters a, b and c may get three sets of values depending on the environment (see below)
and the other parameters are the same as in the previous formula. The model is applicable for distances
100 m – 20 km.
The parameter set that is closest to the rural environment in Tyrnävä is the one for low tree density and
flat terrain. Then the constants are: a = 3.6, b = 0.005 and c = 20. The complete model defines also a
distance dependent standard deviation for the path loss, but it is not discussed further in this document.
5.5.6.1.3 Probability of LOS
There are few references about the LOS probability. Especially for the rural environment where relatively
high BS antenna heights are likely to be used. Reference [30] discusses LOS probability in a peer to peer
and ad-hoc environment, where the antenna heights are low. The result is that the LOS probability
decreases from one to zero approximately in the interval 30 m to 300 m. No formula for the decay is
given.
In [SCM] there is a model given for the LOS probability. The probability formula proposed is
p LOS (d) = (d 0 - d) / d 0 , 0 < d