Contents Telektronikk - Telenor

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≈ first first year year
26 fortnights
second year
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sity, the measurement period as a preselected
time for measurements, and the
dimensioning hour intensity, created by
certain rules and prognoses from the
measured or estimated intensities.
In the choice of intensity measurement
routine, the knowledge of traffic profile
stability is important: if they are stable,
the short pre-selected measurement periods
save data handling capacities; if they
are unstable, continuous measurement
with data post-selection is needed.
In Helsinki Telephone Company (HTC),
from the end of the 1970s to the year
1993, some intensity measurements have
been carried out in order to resolve the
validity of the common assumptions
about stable intensity peaks, and ideality
y%
20 30 50 50
Fortnights
Figure 1 Illustration of two years of peak-hours’ fortnight average
intensities Y in one circuit-group, with its timing error dt and
intensity error y %
dt
of traffic during the
peak-hour. Since the
measuring resources
were convenient, it
was possible to perform
the measurements
on a mass
scale, not only taking
a few samples. Thus,
the results are widely
representative, at
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least in the Helsinki circumstances. The
measurements used the methods and routines
which were in daily use in Helsinki;
just the data processing afterwards was
modified in order to simulate different
measurement routines under study.
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Several presentations in international
fora are summarised in the following,
Trunk groups number 2728 trunk groups
-25 -20 -15 -10 -5 0 5 10 15 20 25
Figure 3 Distribution of timing errors dt [5]
0
-20 -10 0 10 20 ∆t
Figure 2 Timing errors dt and intensity errors y % of
2728 circuit-groups [5]. The 305 error-free cases are
not indicated
and their most relevant results are
referred to.
As references are used the Elementary
Conceptions, being formulated to support
the traditional understanding and thus the
high stability of profiles.
3 The high season and
its stability
The Elementary Conception (ElCo)
about seasons is that there is in the year
a season with higher traffic than other
seasons, and it is stable from one year to
another. If the ElCo about seasons is
valid, the intensity measurements can be
concentrated to these seasons only, when
a high load has been discovered in earlier
measurements.
The study object in the Helsinki local
network was the 2728 circuit-groups connected
to the measuring system
AUTRAX. It measured each circuitgroup
continuously, all year round, in ten
consecutive working day rounds, i.e. in
fortnight periods, each being registered
as an average of the days’ peak-hours.
The measurement during two years, 1980
to 1981, thus included 52 fortnightly
intensities. On an average a circuit-group