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

WINNER D5.4 v. 1.4
reflections can be expected due to the free-space conditions from/to the reflectors. Due to lack of
measurements we will use fixed angle-spread, delay-spread and XPR-value. Long and short-term fading
will be used however. Thus only a tapped delay-line model will be provided for this scenario. Note that
due to the single-bounce nature of the propagation, directive antennas are very effective in reducing
delay-spread and other impacts of multi-path, see e.g. the delay-spread reduction in [PT00]. We use the
RMS-delay-spread value of 40 ns. This is the largest value observed in a measurement campaign which
utilized antennas with 53 degrees and 10 degree opening angles in the link-ends, see [PT00]. This is also
close to the median RMS-delay-spread with basically omni-directional antennas measured in [OBL+02]
but somewhat larger than in [SCK05] but the measurements in [SCK05] are at very short range.
Therefore, the model should be understood such that it is applicable using omni-directional antennas for
up to 300meters distance, while beam-widths comparable or narrower that the aforementioned 10/53
degrees should be used at larger distances.
X
X
Figure 4.5: Single Bounce Reflection Model
4.2.2 B5b LOS stationary feeder: street-level to street-level
The measurement campaigns listed in the literature review are performed at very different frequencies: all
the way from 2 to 10GHz. However, in papers e.g. [Bal02], [SBA+02] the results for different carried
frequencies are very similar. Therefore we chose to disregard the difference in frequency for this interim
channel model. The principle adopted for the WINNER models allows for various correlations between
different parameters such as angle-spread, shadow-fading and delay-spread. We will use one such
dependence namely that in [MKA02], which dependence is between path loss and delay-spread. For B5b
however, only Clustered-delay-line models will be provided (CDL) and the dependence between path loss
and delay-spread is handled by selecting one of three different CDL models.
Our understanding of the scenario is that both the transmitter and receivers have many scatterers in their
close vicinity similar as theorized in [Sva02]. In addition there can also be long echoes from the ends of
the street. However, there is a line-of-sight ray between the transmitter and receiver. When this path is
strong the contribution from all the scatters is small and therefore also all the different foRMS of
dispersion. However, beyond the breakpoint distance the scatterers start to play an important role. Based
on the BS and MS height of most references we assume that model is valid for 2-5 meter access point
heights. A clustered delay-line model with the properties given below is defined. The parameters and their
motivations are as follows.
4.2.3 B5c hotspot LOS stationary-feeder: below rooftop to street-level.
This can be modelled identical to the LOS version of the B1 model except that support for the Doppler
spectrum of stationary cases has to be introduced. How to support higher feeder peripheral station
antennas than typical mobile-station heights has not been considered yet.
We propose the introduction of individual Doppler frequencies similar to the model in [TPE02]. The
Doppler frequency will not be a function of the AoA at the receiver since the channel variation is not due
to temporal variations of the channel in fixed applications. We select the Doppler model of [Erc01],
which has somewhat higher Doppler spread than [DGM+03] probably due to the influence of traffic.
4.2.4 B5d hotspot NLOS stationary feeder: rooftop to street-level.
This model is based on C2 model except the Doppler spectrum and an additional term in the path-loss
model. The Doppler spectrum can be handled as in B5c. To support higher heights of the feeder
peripheral stations than in the C2 model, a compensation term is introduced. We have investigated the
term based on the Cost 231 Walfish-Ikegami, Walfish-Bertoni and Hata-models [Cost231], [MBX94],
[Hat80] for the scenario depicted in Figure 3-2. We have set the parameters to w =30meter, x=w/2,
h = h +10
b B . The results for h
B
=12, 18 and 24 meter are shown in Figure 4.7. As a comprise between
these curves we propose a gain from using a higher MS antenna than 0.1meter as
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