WINNER II pdf - Final Report - Cept

WINNER II D1.1.2 V1.2
Doppler information is not specified explicitly for CDL models. This is because Doppler is determined by
the AoAs of the MPCs, MS speed and direction, and the specified antenna patterns at the MS and BS,
upon which there are no restrictions, except in fixed feeder link scenarios, as discussed in the section of
feeder link models.
3.6.1 Cluster Delay Line models for mobile and portable scenarios
Cluster delay line (CLD) models for all mobile scenarios have been generated from the corresponding
generic models by selecting typical values from a set of random channel realisations. The CLD models
consist of the average power, mean AoA, mean AoD, and angle spreads at the BS and MS associated with
each cluster within the cluster delay line models. Tables of CDL parameters for the above-cited scenarios
can be found in Section 6. Although AoA and AoD values are fixed, it is recommended to have
directional variation for e.g. beamforming simulations by adding network layout related angle parameter
Ω MS and Ω BS to all tabulated angles (see Figure 5-2).
3.6.2 Cluster Delay Line models for fixed feeder links
Only CDL models have been created for fixed feeder links (B5 scenarios). Model parameters have mostly
been derived from the literature as described in [WIN1D54], but some of them have been created by
applying models generated in WINNER. CDL models for B5 scenarios are given in the tables of Section
6. As for the mobile and portable scenarios, any desired antenna patterns can be chosen. However, for
scenarios B5a and B5b, at distances greater than 300 metres, the 3 dB beamwidth of the antenna at one
end of the link should be less than 10 degrees, while that at the other end of the link should be less than
53 degrees. Different parameters are specified in the cited tables for scenarios B5a, b, c, and d.
For fixed link scenarios B5a, B5b, B5d and B5f, Doppler shifts are independent of AOAs. Instead, they
are derived from considerations concerning the movement of interacting objects. One interacting object
per cluster is modelled as having motion, while the others are fixed. Associated Doppler frequencies are
specified in CDL tables. For the scenario B5c, two whole cluster are moving with random velocity.
3.6.3 Complexity comparison of modelling methods
Computational complexity of simulation of channel models is an important issue in system performance
evaluations. Complexity comparison of WINNER modelling approach with the popular correlation matrix
based method is studied in [KJ07]. A common supposition is that the correlation method is simpler and
computationally more effective than the geometric method. Conclusion of [KJ07] is that complexity of
both methods is about the same order of magnitude. With a high number of MIMO antenna pairs (>16)
correlation based method is clearly more complex.
The computation complexity is compared in terms of the number of “real operations”. With the term “real
operations” is equated complexity of real multiplication, division, addition and table lookup. In Figure 3-9
the number of real operations per delay tap per MIMO channel time sample (matrix impulse response),
with different MxN MIMO antenna numbers, is depicted assuming 10 or 20 rays (M in eq. 3.3) and 8 th
order IIR filter in correlation matrix method. It was also noted that complexity of channel realisation
generation is several order of magnitudes lower than computational complexity of simulation of channel
convolution.
Figure 3-9. Computational complexity comparison.
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