Signal To Noise Ratio (Snr) - Alcatel OmniAccess Wireless System 2.1 Product Manual

Signal to Noise Ratio (SNR)

Signal to Noise Ratio (SNR)
The SNR view displays the relationship between RSSI and 802.11 Interference and environmental noise
as described in the next section. Under good circumstances, without adjacent, interfering access points
configured on close channels (such as channels 1 and 2), the SNR value should be close to RSSI value.
With high interference, the SNR can drop down to zero, making data transfer very slow or impossible.
SNR is calculated as follows:
Signal to Noise Ratio (SNR) = RSSI - Noise Level
Please note that the SNR visualization is based on a computational worst-case estimate from the
recorded data - not concrete SNR observations from the WLAN card. Momentary SNR values are not
used because they may be affected by momentary variation such as varying number of clients trans-
mitting data, or random radio interference, such as a microwave oven.
The figure below shows that if the Signal-to-Noise Ratio is significantly lower than the signal strength,
there is radio interference affecting your network performance.
The grid and survey route visualizations have been turned off.
11/5/04 Analysis Features
90-100831-300 Rev 2Alcatel OmniAccess Wireless Access Point Quick Installation Guide 24