WINNER II pdf - Final Report - Cept

WINNER II D1.1.2 V1.2
4. Channel Models and Parameters
In this section, we summarize all the channel models and parameters. The path loss models are mainly
based on 5 GHz and 2 GHz measurements. However, the frequency bands are extended for 2 − 6 GHz
range.
It should be noted that the scenarios Indoor-to-Outdoor and Outdoor-to-Indoor have been combined and
represented by a single channel model in this deliverable. This combining has been discussed in Part II
document of this report.
4.1 Applicability
4.1.1 Environment dependence
Different radio-propagation environment would cause different radio-channel characteristics. Instead of
attempt to parameterize environment directly (e.g. street widths, average building height etc.) WINNER
models are using (temporal and spatial) propagation parameters obtained from channel measurements in
different environments. In this context, environments in which measurements are conducted to observe
radio-channel characteristics are called propagation scenarios. For each scenario measured data is
analyzed and complemented with results from literature to obtain scenario-specific parameters. After this
point, same generic channel is used to model all scenarios, just by using different values of channel
parameters.
Usually, even for the same scenario, existence of LOS component substantially influences values of
channel parameters. Regarding to this property, most WINNER scenarios are differentiating between
LOS and NLOS conditions. To enable appropriate scenario modelling, transition between LOS and
NLOS cases have to be described. For this purpose distance dependent probability of LOS is used in the
model.
4.1.2 Frequency dependence
Dependence on carrier frequency in WINNER model is found in path-loss models. All the scenarios
defined by WINNER support frequency dependent path-loss models valid for the ranges of 2 – 6 GHz.
The path-loss models are based on measurements that are mainly conducted in 2 and 5 GHz frequency
range. In addition the path-loss models are based on results from literature, like Okumura-Hata and other
well-known models [OOK+68], [OTT+01], which have been extended to the desired frequency range.
Path-loss frequency dependence has been considered in more detail in the paragraph 4.3.
From WINNER measurement results and literature survey it was found that model parameters DS, AS
and Ricean K-factor do not show significant frequency dependence [BHS05]. For that reason these
parameters show only dependence on environment (scenario).
For modelling of systems with time-division-duplex (TDD) all models are using same parameters for both
uplink and downlink. If system is using different carriers for duplexing (FDD), then (additionally to path
loss) random phases of scatterer contributions between UL and DL are modelled as independent.
For the WINNER purposes it is required that channel model supports bandwidths up to 100 MHz.
Following the approach described in [SV87] (for indoor propagation modelling) and further with SCME
[BHS05] WINNER II model introduces intra-cluster delay spread as a mean to support 100 MHz
bandwidth and to suppress frequency correlation. Instead of zero-delay-spread-cluster approach of Phase I
model, the two strongest clusters with 20 multipath components (MPCs) are subdivided into 3 zero-delay
sub-clusters. Thus we keep the total number of MPCs constant, but introduce four additional delay taps
per scenario.
4.2 Generation of Channel Coefficients
This section gives general description of the channel coefficient generation procedure, depicted also in
Figure 4-1. Steps of the procedure refer to parameter and model tables of Sections 4.2 to 4.4 give the
minimum description of the system level channel model.
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