Users Guide

You can configure the channel reuse feature to operate in either of the following three modes; static, dynamic
or disable. (This feature is disabled by default.)
l Static mode: This mode of operation is a coverage-based adaptation of the Clear Channel Assessment
(CCA) thresholds. In the static mode of operation, the CCA is adjusted according to the configured
transmission power level on the AP, so as the AP transmit power decreases as the CCA threshold increases,
and vice versa.
l Dynamic mode: In this mode, the Clear Channel Assessment (CCA) thresholds are based on channel loads,
and take into account the location of the associated clients. When you set the Channel Reuse feature to
dynamic mode, this feature is automatically enabled when the wireless medium around the AP is busy
greater than half the time, and the CCA threshold adjusts to accommodate transmissions between the AP
its most distant associated client.
l Disable mode: This mode does not support the tuning of the CCA Detect Threshold.
The channel reuse mode is configured through an 802.11a or 802.11g RF management profile. For details on
modifying 802.11a or 802.11g RF management profiles, refer to RF Management on page 593 .
Configuring Non-802.11 Noise Interference Immunity
When an AP attempts to decode a non-802.11 signal, that attempt can momentarily interrupt its ability to
receive traffic. The noise immunity feature can help improve network performance in environments with a high
level of non-802.11 noise from devices such as Bluetooth headsets, video monitors and cordless phones.
You can configure the noise immunity feature for any one of the following levels of noise sensitivity. Note that
increasing the level makes the AP slightly “deaf” to its surroundings, causing the AP to lose a small amount of
range.
l Level 0: no ANI adaptation.
l Level 1: Noise immunity only. This level enables power-based packet detection by controlling the amount of
power increase that makes a radio aware that it has received a packet.
l Level 2: Noise and spur immunity. This level also controls the detection of OFDM packets, and is the default
setting for the Noise Immunity feature.
l Level 3: Level 2 settings and weak OFDM immunity. This level minimizes false detects on the radio due to
interference, but may also reduce radio sensitivity. This level is recommended for environments with a high-
level of interference related to 2.4Ghz, appliances such as cordless phones.
l Level 4: Level 3 settings, and FIR immunity. At this level, the AP adjusts its sensitivity to in-band power,
which can improve performance in environments with high, constant levels of noise interference.
l Level 5: The AP completely disables PHY error reporting, improving performance by eliminating the time the
controller would spend on PHY processing.
Only 802.11n-capable APs simultaneously support both the RX Sensitivity Tuning Based Channel Reuse feature and a
level-3 to level-5 Noise Immunity setting. Do not raise the noise immunity default setting on APs that do not support
802.11n unless you first disable the Channel Reuse feature.
You can manage Non-802.11 Noise Immunity settings through the Non 802.11 Interference Immunity
parameter in the 802.11a or 802.11g RF management profile. For details on configuring this profile, refer to RF
Management on page 593
Troubleshooting ARM
If the APs on your WLAN do not seem to be operating at an optimal channel or power setting, you should first
verify that both the ARM feature and ARM scanning have been enabled. Optimal ARM performance requires
Dell Networking W-Series ArubaOS 6.4.x | User Guide Adaptive Radio Management | 530