The 802.11-2012 standard also defines another metric called signal quality (SQ), the signal quality could be a measurement of what might affect coding techniques, such as the Barker code or Complementary Code Keying (CCK), which relates to the transmission speed. Some SQ parameters might also be used in conjunction with RSSI as part of a clear channel assessment (CCA) scheme.Īlthough SQ metrics and RSSI metrics are technically separate measurements, most Wi-Fi vendors refer to both together as simply RSSI metrics.īecause the implementation of RSSI metrics is proprietary, two problems exist when trying to compare RSSI values between different manufacturers’ wireless cards. Another vendor might use an RSSI metric of 255 to represent –30 dBm of received signal amplitude and 0 to represent –100 dBm of received signal amplitude. The RSSI metric of 0 might be mapped to –110 dBm of received signal amplitude. RSSI metrics are typically mapped to receive sensitivity thresholds expressed in absolute dBm values, as shown in Table 3.4.įor example, an RSSI metric of 30 might represent –30 dBm of received signal amplitude. Wi-Fi vendors will usually specify their receive sensitivity thresholds at various data rates an example vendor specification for a 2.4 GHz radio is listed in Table 3.3. The RSSI value is designed to be used by the WLAN hardware manufacturer as a relative measurement of the RF signal strength that is received by an 802.11 radio. The 802.11 RSSI measurement parameter can have a value from 0 to 255. Received signal strength indicator (RSSI) is a relative metric used by 802.11 radios to measure signal strength (amplitude). It is the weakest signal that the transceiver can decode under normal circumstances. The lower the power level that the receiver can successfully process, the better the receive sensitivity. Receive sensitivity refers to the power level of an RF signal required to be successfully received by the receiver radio.

RSSI (Received Signal Strength Indicator)

Wifi rssi level