RRM Design

On a WLAN, especially on the 2.4 GHz frequency band, out-of-band interference and in-band co-channel/adjacent-channel interference exist. STAs of different brands, types, and models behave differently. For optimal access services, radio resources and user access need to be managed in a coordinated manner. The specific radio resource management (RRM) capabilities include:

• Radio calibration

  The radio calibration function can dynamically adjust channels and power of APs managed by the same WAC to ensure that the APs work at the optimal performance. It is recommended that scheduled radio calibration be configured so that APs perform radio calibration in off-peak hours, for example, between 00:00 am and 06:00 am.

• Band steering

  Most STAs support both the 2.4 GHz and 5 GHz frequency bands. Generally, the 2.4 GHz frequency band is selected by default, on which a smaller number of channels are available. The 2.4 GHz frequency band is usually crowded and heavily loaded, and suffers high interference. In contrast, the 5 GHz frequency band with multiple channels and low interference cannot be brought into full play. The band steering function enables an AP to steer STAs to the 5 GHz radio first, which reduces traffic load and interference on the 2.4 GHz radio and improves user experience. It is recommended that this function be enabled by default.

• Smart roaming

  Some outdated and dumb terminals have low roaming aggressiveness. As a result, they stick to the initially connected APs regardless of the long distance from the APs, weak signals, or low rates. The STAs do not roam to neighboring APs with better signals. Such STAs are generally called sticky STAs. The negative impact of sticky STAs is described as follows:

  • The service experience of a sticky STA is poor, and the STA is always associated with the poor-signal AP. As a result, the channel rate decreases significantly.
  • The overall performance of wireless channels is affected. A sticky STA may encounter frequent packet loss or retransmission caused by poor signal quality and low rates, and therefore occupies the channel for a long time. As a result, other STAs cannot obtain sufficient channel resources.

  Smart roaming enables STAs to roam to neighboring APs with better signals in a timely manner, improving user experience.

  • Performance improvement

    Smart roaming can direct poor-signal STAs to APs with better signals, improving user service experience and overall channel performance.

  • Load balancing

    Smart roaming ensures that each STA is associated with the nearest AP, achieving inter-AP load balancing. It is recommended that this capability be enabled.

• STA steering

  After a STA connects to an AP, the target AP selection algorithm is used to comprehensively measure the dual-band capability of the STA, AP load, and AP signal quality to steer the STA to the optimal AP. It is recommended that this capability be enabled.