What is RSSI and its acceptable signal strength?
RSSI stands for Received Signal Strength Indicator. It is an estimated measure of power level that an RF client device is receiving from an access point or router.
At larger distances, the signal gets weaker and the wireless data rates get slower, leading to a lower overall data throughput. Signal is measured by the receive signal strength indicator (RSSI), which in most cases indicates how well a particular radio can hear the remote connected client radios.
Indoor RSSI Set-Up Best Practices
Indoor RSSI Maximums
For mixed use networks:
-75 dB to -80 dB
For session based networks: (Such as video conferencing, Wi-Fi calling, inventory management, etc.)
-60 dB to -65 dB
Recommended Tx Output Power on APs
For mixed use networks: (Such as web browsing, accessing email, etc.)
18 dBm to 20 dBm on the 5 GHz radio
11 dBm to 14 dBm on the 2.4 GHz radio
For session based networks:
11 dBm to 15 dBm on the 5 GHz radio
11 dBm on the 2.4 GHz radio
Channel Width Relation to RSSI
Wider channels normally have lower RSSI values. Therefore, smaller channel widths are recommended in all but some special circumstances; when configuring EnGenius APs.
Note: Special circumstances are low AP density deployments, such as a small home network. A wider channel setting should only be considered after the RF deployment has been qualified. (40 MHz - 80 MHz and channel widths)
Visualize your project's RSSI through the subscription-free network design tool, ezWiFi Planner. Try it now to measure your project's projected coverage.
Source : https://helpcenter.engeniustech.com/hc/en-us/articles/234761008-What-is-RSSI-and-its-acceptable-signal-strength-#:~:text=RSSI%20stands%20for%20Received%20Signal,a%20lower%20overall%20data%20throughput.