Cisco Cisco Aironet 350 Mini-PCI Wireless LAN Client Adapter Designanleitung
3-26
Enterprise Mobility 4.1 Design Guide
OL-14435-01
Chapter 3 WLAN Radio Frequency Design Considerations
Manually Fine-Tuning WLAN Coverage
Figure 3-12
Channel Allocated To APs
A site survey should be conducted using the same frequency plan as intended for the actual deployment.
Some sites have high noise backgrounds which may prohibit the use of one or more channels. This
provides a better estimate of how a particular channel at a particular location will react to the
interference and the multipath. Channel selection also helps in planning for co-channel and the adjacent
channel interference, and provides information about where you can reuse a frequency (see
Some sites have high noise backgrounds which may prohibit the use of one or more channels. This
provides a better estimate of how a particular channel at a particular location will react to the
interference and the multipath. Channel selection also helps in planning for co-channel and the adjacent
channel interference, and provides information about where you can reuse a frequency (see
In multi-story buildings, check the cell overlap between floors, especially where windows may be located,
according to these rules/guidelines. Careful pre-planning and selection of AP location might be required
in approximately 10 percent of the cases. Multi-story structures such as office towers, hospitals, and
university classroom buildings introduce a third dimension to coverage planning. The 2.4 GHz
waveform of 802.11b and 802.11g can pass through many walls. The 5 GHz waveform of 802.11a has
approximately half the tendency for a given power to transmit suitable amounts of energy through walls
because of its higher frequency. With 2.4 GHz Wi-Fi LANs in particular, you must not only avoid
overlapping cells on the same floor, but also on adjacent floors when coverage models include cells that
cover windows on both floors. With only three channels, this can be achieved through careful
three-dimensional planning.
according to these rules/guidelines. Careful pre-planning and selection of AP location might be required
in approximately 10 percent of the cases. Multi-story structures such as office towers, hospitals, and
university classroom buildings introduce a third dimension to coverage planning. The 2.4 GHz
waveform of 802.11b and 802.11g can pass through many walls. The 5 GHz waveform of 802.11a has
approximately half the tendency for a given power to transmit suitable amounts of energy through walls
because of its higher frequency. With 2.4 GHz Wi-Fi LANs in particular, you must not only avoid
overlapping cells on the same floor, but also on adjacent floors when coverage models include cells that
cover windows on both floors. With only three channels, this can be achieved through careful
three-dimensional planning.
As a final step, after setting up the WLAN network, you should always retest the site using the selected
channels and check for any interference. Keep in mind that the RRM algorithms are logical and subject
to the physical topology of the network. It thus takes into account the three-dimensional placement of
APs and provides the optimal channel/power setting for the sampling interval.
channels and check for any interference. Keep in mind that the RRM algorithms are logical and subject
to the physical topology of the network. It thus takes into account the three-dimensional placement of
APs and provides the optimal channel/power setting for the sampling interval.
Manual Channel Selection
shows a screenshot of the web page for configuring one of the 802.11b/g radios under the
wireless selection. On the top right-hand side, channel 11 has been manually selected and the transmit
power is set to 1, the highest level (8 sets the AP to the lowest level).
power is set to 1, the highest level (8 sets the AP to the lowest level).
Note
The assignment method should normally be left at the global setting, unless there is a desire to manually
control these settings. This allows the controller to dynamically change the channel number and transmit
power as determined by the RRM. See
control these settings. This allows the controller to dynamically change the channel number and transmit
power as determined by the RRM. See
for more
information.
221933
AP1
Channel 1
AP2
Channel 6
AP3
Channel 6
AP4
Channel 11
LWAPP
LWAPP
LWAPP
LWAPP