Specifications
20 Basic Cell Planning
The 5 GHz band consists of several sets of channels listed in the table below. See also Section ,
“802.11a Radar Protection, Dynamic Frequency Selection (DFS)”, on page -13.
NOTE: The handset supports, but does not make use of, 40 MHz channel bonding. The channels
to support in the handset can be configured using PDM, or the Device Manager(WSG).
NOTE: For examples on channel placing layouts refer to manufacturers planning documentation.
For a multi-cell system based on 802.11 the following factors affects the cell planning:
• Coverage
•Capacity
• Roaming
• Noise interference
The wireless cell planning is done using an AP placement tool which estimates the placement of
APs based on the building/campus characteristics. It is recommended that a site survey is done
using the built-in tools in the handset. The tool provides a true measurement of the RF environ
-
ment based upon the radio of the handset. Other wireless analyzers can be used to provide addi-
tional assistance during a site survey.
The basic approach to cell planning is to have sufficient overlap between adjacent cells in order
to ensure that sufficient radio signal strength is present during a handover between the cells, see
<Blue>Figure 3.
Figure 3.
Figure 3 Cell overlap between adjacent cells
The distance between the APs is often a trade-off between the amount of APs and coverage.
To make up for fading effects in an indoor office environment it is recommended that the radio sig-
nal strength at the cell coverage boundary does not drop below -70 dBm. The APs should be
placed to overlap their boundaries by approximately 6–10 dB.
This means that when the STA reaches a point where the RSSI is -70 dBm, the STA is also inside
the adjacent cell and the RSSI from that AP is between -60 to -64 dBm. For information on distance
attenuation and attenuation in construction materials, see
Section , “RF Signal Corruption in an
VoWiFi System”, on page -21.
Radio ETSI FCC
2.4GHz, 802.11b/g/n 20MHz 3 3
5GHz, 802.11a/n 20MHz 4 + 15 (DFS) 9 + 12 (DFS)
2.4GHz, 802.11n 40MHz 2 1
5GHz, 802.11n 40MHz 2 + 7 (DFS) 4 + 5 (DFS)