How SNR can have minus values ? Any theoritical explanation?

Dear All,

I have a test bed and get RSSI around -110 dBm and SNR -9 dB.

Due to RSSI calculation method I find the Psignal around 10^-14 watts that is taken in receiver. How is that possible ? Also similar power levels in SNR calculation.

What is the average received power levels in LoRa GW receiver ? Can someone make it more clear ?


see here
it says that when SNR is greater than 0 dB, then you have more signal than noise.
So when you have more noise than signal, you have a negative dB SNR.