Reduction of sensitivity for received packets

In high-density scenarios such as stadiums, exhibition halls or auditoriums, it is inevitable that access points that use the same channel will use the medium to a high capacity. This can result in a situation where the access points withhold their transmissions to the clients because the channel is recognized more often as busy.

An access point can be set artificially "deaf" by reducing the reception sensitivity from LCOS 10.30 RU1 onwards. This means that transmissions further away from the access point are "overheard" and the channel is detected more often as "free". In simplified terms, more simultaneous transmissions on the same channel are possible. On the one hand, this increases the overall throughput of a system, but on the other hand, the interference on the client side also increases.

Because a client does not know anything about the artificial hearing loss, it continues to receive the desired signals from its access point as well as the signals from other access points on the same channel. Only if the signal-to-noise ratio (SNR) remains good, the the additional transmissions will be received properly by the client thanks to this feature. Another side effect of the clients' ignorance is that a value set too high can reverse the effect. Since the access point cannot distinguish between transmissions from its own clients and from other devices—both access points and clients—only what is above the set threshold is heard—no matter from whom it comes. It may happen that the transmission of a connected client from the access point is no longer "heard". This results in an asymmetrical connection, the client may still receive the access point properly and therefore assumes a good connection, while the access point does not notice anything from the client anymore and ignores it. It is recommendable to set the reduction so that there is no discrimination against clients.

You set the reduction via the console in value Setup > Interfaces > WLAN > Radio-Settings > Rx-Packet-Sens.-Reduction. The value range from 0-20 corresponds to a minimum reception strength in the range from -95 dBm (0) to -75 dBm (20). In principle, Wi‑Fi radio modules are subject to manufacturing variations. As a result, the real reception strength can deviate slightly.

For WLAN controllers, this setting can also be made via the console in the profile of an access point. Under Setup > WLAN-Management > AP-configuration > Accesspoints adjust the values Module-1-Rx-Packet-Sens.-Reduction resp. Module-2-Rx-Packet-Sens.-Reduction accordingly.

Important: This feature is for experts! As already mentioned in the description, instead of adding value, it can also have the opposite effect and disrupt transmissions on the access point side. On the one hand, the reduction should be configured with a buffer to the usual RSSI values of the clients on the access point side. On the other hand, the retries and Wi‑Fi quality indices must be observed. If these deteriorate significantly after increasing this value, this indicates that the value is too high.

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