User's Manual

Chapter 4 - Operation and Administration
BreezeACCESS VL System Manual
144
force the SU(s) to re-initiate the association process, including the search for the
best AU (or a preferred AU) using the Best AU process, without performing a full
reset.
The Disassociate submenu includes two options:
 Disassociate All SUs
 Disassociate SU By MAC Address: to disassociate a selected SU
4.2.6.2.18 Noise Immunity Control
The Adaptive Noise Immunity (ANI) mechanism is designed to reduce the wireless
physical layer errors and by that enhance the AU processing power of the unit,
delivering higher packet processing efficiency.
This ANI mechanism is triggered by the rate of detected Physical Errors and it is
modifying different thresholds affecting the immunity to specific interference
types.
This feature, active by default, exists in all units with HW revision C and higher
running SW version 3.0 and higher. Starting in SW version 4.0, the processing
power of the system has been increased dramatically. When using version 4.0 the
units are capable to process more packets per seconds, including physical error
packets. As a result, the ANI mechanism (triggered by the number of received
error packets) may not function properly in certain scenarios, resulting in link
performances that are far below the expectations. The option of manually
controlling the various parameters used by the ANI mechanism enables to
achieve optimal performance in certain deployments where the automatic ANI
mechanism may not function properly.
It is strongly recommended to consult with Alvarion experts before switching to
manual mode and modifying any of the parameters.
The general rules for using the Noise Immunity Control parameters are:
In the SU, if performance (Modulation Level) is lower than expected based on the
SNR, try switching to Manual mode without changing any of the parameters.
CAUTION
Do not change any of the SU’s Noise Immunity Control parameters (except the Noise Immunity
State Control) from remote, as it may result in loss of connectivity to the unit.
In the AU, try switching to Manual mode if overall throughput is too low or if SUs
are lost although communication conditions are sufficient for good connectivity.
In many deployments the transition to Manual mode is sufficient. If not, you may
try changing the Noise Immunity Level and/or Spur Immunity Level parameters.
The target is to reduce the amount of Phy Error rate reported by the unit (see