RSSI Calculations

[dan-pistorino]

I am new to developing RF applications but am tasked with developing a signal profile for a LoRa sensor node. I want to use the lsnr and rssi values calculated by the gateway to map signal strength over a set of environmental parameters. I need to explain how the rssi and lsnr values are calculated, but I am unable to find this in the source code. I searched the semtec radio source code, but it seems like it is pulling the rssi value from a register. Can you refer me to where the libraries calculate the RSSI value by measuring received power or voltage? I am also trying to find the source for the lsnr value.

I have the NUCLEO-F746ZG (+ RisingHF LRWAN_GS_LF1 LoRa riser) configured as a gateway and a NUCLEO-WL55JC2 setup as a node. The gateway and sensor are communicating as shown in the images below. The lsnr and rssi values I am trying to explain are the values reported by the gateway in these images.

Thank you for any help you can provide.

[STTwo-32]

Hello @dan-pistorino 

As you can see on the Figure 13 of the UM2587, the LRWAN_GS_LF1 is based on the SX1255 and SX1301. So, this value should be provided by the Semtech modules. I suggest you take a look at the sx1301-1523429.pdf specially part 3.7.1. It should give you an idea about how to extract the SNR and RSSI of your received message. For more details, you can contact Semtech on the Contact | Semtech Corporation | Semtech

Best Regards.

STTwo-32