dBm（RSSI）与信号强度

Generally,
dBm >= -50 dBm = 100% quality
dBm <= -100 dBm = 0% quality

For RSSI signal between -50dBm and -100dBm,
quality ~= 2* (dBm + 100)
RSSI ~= (percentage / 2) – 100

For example:
High quality: 90% ~= -55dBm
Medium quality: 50% ~= -75dBm
Low quality: 30% ~= -85dBm
Unusable quality: 8% ~= -96dBm