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About RSSI of STM32WL.

Weili
Associate II

Hi ST experts.

I used the pingpong sample code to test RSSI and SNR. I set SF=12, BW=62.5Khz.

I used SX1261 calculator tools to calculate, under this condition, its RSSI can reach -140dBm.

Weili_0-1701143447749.png

But during my actual test, our RSSI reached -120dBm and the SNR was unable to receive data after it reached -20dBm.

Weili_1-1701143713323.png

 

This is a module we designed ourselves. Is this normal behavior?

 

 

 

1 ACCEPTED SOLUTION

Accepted Solutions
STTwo-32
ST Employee

Hello @Weili 

the difference between the expected and actual RSSI values could happened in multiple cases such as the antenna characteristics, the interference or noise in the environment that is affecting the signal quality,...

Best Regards

STTwo-32

 

To give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

View solution in original post

2 REPLIES 2
STTwo-32
ST Employee

Hello @Weili 

the difference between the expected and actual RSSI values could happened in multiple cases such as the antenna characteristics, the interference or noise in the environment that is affecting the signal quality,...

Best Regards

STTwo-32

 

To give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

RL
ST Employee

The RSSI tested in STM32WLxx or SX126x chipset means the channel signal rssi, so when the signal strength below the noise, the tested rssi equal the noise's one, otherwise, the tested rssi is the truth, so we need to add the SNR number in the tested data as the truth rssi in this condition.  

Eg, RSSI=-119 dBm, SNR= -22dB, the signal RSSI= -119+(-22) = -141dBm.

hope this answer is useful to you!

 

BR.