Radio resource management enables a WLAN to adapt to changes in the radio environment by dynamically adjusting radio resources. This improves service quality for wireless users.
WLAN technology uses radio signals (such as 2.4 GHz or 5 GHz radio waves) as a transmission medium. Radio signals are attenuated during transmission in the air, degrading service quality for wireless users. Radio resource management (RRM) enables APs to monitor the surrounding radio environment and adapt to changes in the radio environment by dynamically adjusting working channels and transmit power, reducing radio signal interference, and evenly distributing access to users.
RRM helps reduce radio signal interference, adjust radio coverage, and enable a wireless network to quickly adapt to changes in the radio environment. With the RRM function, the wireless network can provide high service quality for wireless users and maintain an optimal radio resource utilization.
In 2.4Ghz there are 3 non-overlapping channels 1,6 and 11 or channels 1,5,9,13 with small overlap.
After channel adjustment, each AP is allocated an optimal channel to minimize or avoid adjacent-channel or co-channel interference, ensuring reliable data transmission on the network.
The picture below should help understand this better.
The 5 GHz frequency band has even richer spectrum resources. In addition to 20 MHz channels, APs working on the 5 GHz frequency band support 40 MHz and 80 MHz channels. Please check the picture below for channels and 20/40/80 Mhz bands.
To help with the Radio resource management there are 3 radio calibration modes:
1.Auto mode: The device periodically implements global radio calibration at regular intervals (the interval is specified by interval and the default interval is 1440 minutes, and the start time for radio calibration is 03:00:00).
In auto mode, the device continuously detects neighbors and updates neighbor information. When a radio calibration interval is reached, global radio calibration is triggered
Automatic mode (enabling automatic channel selection): An AP automatically selects a proper channel based on the WLAN radio environment, removing the need to specify channels manually.
Automatic mode (enabling automatic transmit power selection): An AP automatically selects or adjusts the transmit power based on the WLAN radio environment, removing the need to specify AP power manually.
If auto mode is selected you cannot manualy set the channel
2.Manual mode: The device does not proactively perform radio calibration. You need to run the calibrate manual startup [ { ap-group group-name }&<1-4> | ap-id ap-list ] command to trigger global calibration or partial calibration based on the AP or AP group.
Example how to Manually trigger radio calibration.
<AC6605> system-view
[AC6605] wlan
[AC6605-wlan-view] calibrate enable auto
[AC6605-wlan-view] calibrate manual startup
Warning: The operation may cause business interruption, Continue? [Y/N]:y
3.Schedule mode: The device triggers global radio calibration at a time specified by the parameter time.
Please note that:
-Some functions are dependent on channel scanning, for example, radio calibration, smart roaming, and WIDS. After such a function is configured, a channel switchover during the scanning increases the users service data delay, which may affect wireless service experience.
-Radios in monitoring mode do not participate in calibration.
-Radio calibration does not take effect on radios enabled with WDS or Mesh functions.
-Radio calibration is not applicable to scenarios where APs cannot detect each other, for example, APs use directional antennas, are far from each other, or have obstacles between them.
-Radio calibration is not applicable to high-density, WDS/Mesh backhaul, rail transportation, or external directional-antenna scenarios.
For configuration example check the below link:
http://support.huawei.com/hedex/pages/EDOC1000175838NEG1031N/02/EDOC1000175838NEG1031N/02/resources/dc/dc_wlan_example_rrm_0005_copyto.html?ft=0&fe=10&hib=9.1.10.16.1&id=dc_wlan_example_rrm_0005&text=Example for Configuring Radio Calibration&docid=EDOC1000175838
If you have any questions regarding this topic please do not hesitate to leave a comment below :)
