Infrastructure Dependant Features
Automatic RF Adaptations in WLAN Systems
Infrastructure Dependant Features
This chapter includes information on tools and features dependant on the WLAN infrastructure.
Automatic RF Adaptations in WLAN Systems
Many WLAN infrastructures make use of an internal tool that is changing the AP channels and/or
transmit power level in a dynamic way. The intention of the tool is to compensate for changes in
the RF environments due to layout changes of furnishings and/or AP failure.
However, very frequent dynamic changes (that happen multiple times per day) make the RF
environment inconsistent and are not recommended when real-time applications like VoWiFi
are deployed. The effects of dynamic RF adaptations when APs switch channels are dropped
speech frames and, at worst, dropped calls.
If the power level is changed, the link budgets may be asymmetrical with co-channel interfer-
ence as a result, which makes the WLAN system perform poorly. The handset monitors the out-
put power of the APs and automatically adapts itself to match in the best way possible.
Load Balancing
Some WLAN infrastructures have an automatic load balancing feature. The purpose is to dynam-
ically move stations between APs to avoid overload and to spread the load. The move of the sta-
tions is done by forcing them to connect to another AP than the current one.This forced transition
causes a loss of speech frames and, in worst case, the call is disconnected.
OpenScape WLAN Phone WL4
OpenScape WLAN Phone WL4 does not support any procedure for a smooth transition of sta-
tions between APs. Instead, the move is done by deauthenticating the handset until it associates
to another AP.
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