SNR (Signal-to-Noise Ratio) is a ratio based value that evaluates your signal based on the noise being seen.
SNR is comprised of 2 values and is measured as a positive value between 0db and 120db and the closer it is to 120db the better: Signal Value and Noise Value typically these are expressed in decibels (db).
NOISE is any signal (interference) that is not WiFi traffic such as cordless phones, microwaves, radar, etc.Noise value is measured in decibels from 0 (zero) to -120 (minus 120) now when looking at this value the closer to -120 (minus 120) is better because that means there is little to no interference. Typical environments range between -90db and -98db.
SNR calculation:
So to calculate your SNR value you add the Signal Value to the Noise Value and it generates a positive number that is expressed in decibels (db); for example lets say your Signal value is -55db and your Noise value is -95db.
-55db + -95db = 40db this means you have an SNR of 40,
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In Huawei environments SNR can be configure for RRM (Radio Resource Management) Protocols such as Smart-Roaming & Band-Steering & User CAC
How ?
Answer : As you know huawei WLAN environments includes many radio management configurations,and all of these standarts have only one purpose;enhance STA(Terminal Device) performance,at this point SNR value can be used in these standarts to allocate a threshold for customer terminal signal value in order to decide initiate Smart Roaming ? Band Steering ?
For Example :
The smart-roam snr-margin command sets the SNR difference threshold that triggers terminal roaming.
By default, the higher and lower SNR difference thresholds that trigger terminal roaming is 15 dB and 6 dB, respectively.
Example
# Set the higher and lower SNR difference thresholds that trigger terminal roaming to 10 dB and 6 dB, respectively.
<AC6605> system-view[AC6605] wlan[AC6605-wlan-view] rrm-profile name huawei [AC6605-wlan-rrm-prof-huawei] undo smart-roam disable [AC6605-wlan-rrm-prof-huawei] smart-roam snr-margin high-level-margin 10 low-level-margin 6
