Deployment
The capacity of the multi-cell system must be high enough to guarantee that subscribers can be reached in high-density
traffic. The capacity of the multi-cell system is determined by the following:
l
Number of connection channels available. Connection channels are used for phone calls and for list access actions
(when the handset accesses the History or Directory).
l
Grade of service (GoS) determines the number of connections that may not be achieved due to the system being at
full capacity. With a grade of service of 5%, it is permissible for 5% of 300 calls (15 connections) not to be
established. This means that only 285 connections have to be achieved.
To calculate the number of connection channels required, use the following formula:
(<Number of calls per hour> – (<Number of calls per hour> x <GoS%>)) x <Average length of call per
hour> / 60 min.
As an example, you set the GoS at 5% and you require 300 calls per hour at an average length of 5 minutes each. The
equation would be: (300 – (300 x 5%)) x 5/60 = 23.75. This means that 24 connection channels would be required, and
you would need 3 base stations.
Since the traffic volume is not normally evenly distributed over the site to be covered, the traffic volume must be
calculated for each area (offices, hotspots, stairwells) to determine the number of base stations that need to be
installed.
Estimating number of base stations based upon area
Estimate the approximate number of base stations according to the total area of expected DECT coverage.
The calculation for this is:
Number of base stations = <size of coverage area (in square meters)> / 800
The suggested distance between two base stations depends on the physical path between the base stations.
The following table lists the recommended distance between two base stations:
Area
Distance between two base stations
Office areas
Up to 40 meters
Office areas with obstacles such as elevator shafts,
stairwells or metal walls
Up to 10 meters
Shop floors
Up to 60 meters
Exhibition halls or production areas without obstacles
Up to 100 meters
Underground garages
Up to 20 meters
As the base stations can interfere with each other, sufficient distance should be maintained between two base stations.
The minimum distance depends on the circumstances. If there are no obstacles between them, the required distance
can be from 5 to 10 meters. If there are obstacles such as absorbent walls or absorbent furniture between them, 1 to 2
meters may be sufficient.
FortiFone FON-D72 User Guide
11
Fortinet Technologies Inc.
