Table of Contents
Advertisement
Planning
5. 3. 2. 5
Traffic density
Once the supply range has been located and covered, the locations for the radio
units are known.
The second phase now looks at other requirements: The traffic volume, determined
by the number of cordless phones and the frequency and duration of connections
in an area defined by the customer. In most cases such a zone does not match the
coverage range of a radio unit.
For each zone you now need to determine how many radio units are currently be-
ing used to supply them. It may be necessary to boost the coverage with additional
radio units for insufficiently supplied areas (in accordance with the customer's re-
quirements). To do so we need to refer back to the radio unit locations that were
determined for the area coverage. For instance, it is a good idea to place additional
radio units at the centre of a zone with a higher traffic volume, even if those units
end up between two already positioned radio units.
To determine the traffic volume, we assume three typical ranges: "low", "medium",
"high". "High" means that approx. 50% of all cordless phones are making calls si-
multaneously. It is also important to note that the volume of traffic can vary consid-
erably in the course of a day. The question is always whether or not to cover a traffic
volume that may be higher only briefly in a particular zone.
5. 3. 2. 6
Hotspots
A hotspot is an area with an above-average number of cordless phones. Such an
area can be covered with several radio units as the resources in the coverage range
of neighbouring radio units are cumulated. It is also advisable to cover hotspots
with several SB-8 (or SB-4+) radio units, and, in CM_2.4.1, to set
mode
to No. This way, the radio units work in "zero-blind-spot mode" and calls can
be distributed over 120 radio channels (instead of over 60 of them in "blind-spot
mode").
In practice it has emerged that interference from neighbouring channels in a
hotspot without special measures means that only approximately one quarter of
the radio channels can be used simultaneously. This means that approx. 30 simulta-
neous connections are possible, which require for example four SB-8 radio units.
Thus approx. 60 cordless phones can be used in a hotspot with a high traffic vol-
ume (simultaneous call connections of approx 50% of the cordless phones). It is es-
sential to observe the minimum distances when installing the radio units (see
Chapter "Installing the radio units" in Aastra 415/430 or Aastra 470 system manual).
42
GAP compatibility
Planning Aastra 400 DECT systems as of R1.0
syd-0457/1.0 – R1.0 – 10.2012
Advertisement
Table of Contents
