What does this metric in WCS tell us, exactly? I could not find an explenation in any of the guides.
This is found on the Radio Details - On Demand Statistics page of each WAP.
I found this to be a good explanation of SNR Cutoff recommendations which this graph seems to relate to. Basically it tells you for the radio
what SNR the clients are reporting for that AP radio. This gives you an idea of the percentage of clients that are hearing it at a good level versus a bad level.
You may want to ask specific questions regarding power and design in a forum more related to that since I am answering this from the WCS side.