Base Station Coverage: In Practice
Page 9
Base Station Coverage: In Practice
In practice, no rules can be given for base station coverage. Coverage is affected by
many factors that are unique to each site. We can only guide you as to those things
that are likely to affect base station coverage
Obvious causes of signals problems:
– Metal surfaces, concrete thickness greater than one metre
Beware of:
–
Windows with reflective film or specialised glass: (e.g. Pilkington 'K')
This type of glass, e.g. car windscreens, produces increased signal
reflection and reduces signal pass-through
–
Wire Meshes and Grills with apertures of less than 4cm:
These block signals as effectively as continuous metal sheet
–
Fire Doors:
These block the signals. In multi-occupancy building such as hotels the high
number of fire-doors may be a problem
–
Stair Wells:
In modern office buildings, stair wells frequently combine concrete building
supports, fire doors and the intervening floor material, making them a special
problem
–
Screened Rooms:
Typically found in offices involved with TV, video and radio production, but
also possible in computer centres
Base station overlap areas:
– In overlap areas, the signal from one base station is getting weak and so the
handset will start call handover to the next base station. However this
process can take up to 10 seconds. In overlap areas look out for items such
as closing doors that might suddenly block the already weak signal before
handover is completed
–
To calculate the overlap required, based on the handset user's speed, allow
10 seconds to guarantee handover.
_ Remember that base stations located on different floors will add to the
number of overlaps
– Ideally base stations should be a minimum of 25 to 40 metres apart.
–
The number of base station signals which can be monitored by DECT
Handsets is four.
– Do not put more than 3 DBSs in a cluster for the purpose of maximising call
capacity, i.e. within 25cm of each other
Opportunities to be aware of:
– In multi-storey buildings, if the building construction allows, a base station on
one floor can also serve the floor above or below
Installation Manual
Page 9
INDeX CSLC
38DHB0002UKCA – Issue 8 (26/03/2002)