Controller Based WLANs

Co-Channel Interference or CCI is crosstalk from two different radio transmitters using the same frequency. There can be several causes of co-channel radio interference; for example: In some dense deployments, it is possible for APs to hear other APs on the same channel. This creates co-channel
interference and reduces the overall usage of the channel in a given area.

Channel reuse enables dynamic control over the receive (Rx) sensitivity in order to improve spatial reuse of the channel. The channel reuse feature applies to non-DFS channels only. It is internally disabled for DFS channels and is does not affect DFS radar signature detection

Channel reuse feature can be configured to operate in either of the following three modes: 

• Static
• Dynamic
• Disable

NOTE: This feature is disabled by default.

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.

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.

Disable mode: This mode does not support the tuning of the CCA Detect Threshold.


Where to Configure:

The channel reuse mode is configured through an 802.11a or 802.11g radio profile as shown in the following image:

Rx Sensitivity Threshold: If the Rx Sensitivity Tuning Based Channel reuse feature is set to static mode, this parameter manually sets the AP’s Rx sensitivity threshold (in -dBm). The AP will filter out and ignore weak signals that are below the channel threshold signal strength. If the value for this parameter is set to zero, the feature will automatically determine an appropriate threshold.