LoRaWAN 915 FTD – User guide version 1.0
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ANNEX 2: RSSI and SNR
The uplink frame contains information about the RSSI and the SNR of the previous DL.
RSSI
The RSSI value is the actual absolute value in dB. It is in fact a negative number.
Example: if the value is 100, this means that the RSSI is -100 dBm
SNR
The SNR value is a signed value in two’s complement, ranging from -128 to +127
Values from 0 to 127 are positive values: 0=0; 1=1; 2=2…
Example: if the value is 10, the SNR is +10dB
Values from 255 to 128 are negative values: 255=-1; 254=-2; 253=-3…
Example: if the value is 251, the SNR is -5dB