Wi-Fi Receiver Sensitivity

The sensitivity of a radio is the minimum signal level at the input port required to demodulate and decode a signal.

Wi-Fi Receiver Sensitivity is specified in dBm and varies between -82 dBm and -48 dBm.

Wi-Fi Sensitivity Requirements

The table below from the 802.11 ac standard shows sensitivity as a function of modulation and bandwidth

The simplest modulation BPSK with the narrowest bandwidth of 20 MHz has a minimum Sensitivity of -82 dBm.

Contrast that with the most complex modulation format 256 with 160 MHz of bandwidth. In this case the minimum sensitivity is -48 dBm.

256-QAM provides a higher data rate than BPSK. The higher sensitivity requirement (-48 dBm vs -82 dBm) means the Wi-Fi client (laptop) will have to be closer to the Access Point as expected.

To get a higher data rate, the RSSI has to be higher.

RSSI to Internet Speed

This can be seen in the table below for Wi-Fi speed measurements we made. Higher levels of RSSI translate to faster upload and download speeds.

RSSI (dBm)Download (Mbps)Upload (Mbps)