User manual

Chapter 2 - Managing a Single Device/Cell Air Interface General Page
AlvariCRAFT Device Manager 44 User Manual
2.3.6 Noise Floor Parameters
The Noise Floor calculation mechanism incorporated in the units is used for
estimating the level of the noise floor. This value is used for estimating SNR values
and for decisions on existence of signals in the channel. In some cases, especially
when a very strong signal exists in neighboring channels, the noise floor
calculated by the built-in mechanism may be significantly below the actual noise
floor level.
Typically, the expected noise floor level is:
 5 MHz bandwidth: -102 (dBm)
 10 MHz bandwidth: -99 (dBm)
 20 MHz bandwidth: -96 (dBm)
The default calculation mode is Fully Automatic, using only the built-in
mechanism. If you experience problems in the wireless link such as excessively
long association process or very low throughput, it may be caused by errors in
noise floor calculation. In this case, it is recommended to perform a Spectrum
Analysis and view the Average Noise Floor values. If the calculated Noise Floor is
lower by more than 5 dB from the expected value, it is recommended to change
the calculation mode to Automatic with Minimum Value, using the expected value
as the minimum (Forced Value).
Note that if the SNR of received signals is very low (typically below 10 dB), it is
recommended to maintain the default calculation mode (Fully Automatic).
Changing the calculation mode to Automatic with Minimum Value may result in
loss of connectivity with units for which the calculated SNR before the change was
relatively low.
The Noise Floor Parameters include the following: