Issue with FSK Packet Reception During LCTT Certification

[saikrishna]

Dear ST Team,

We are working on the design and development of a LoRa/LoRaWAN end device using the STM32WB55RG and LR1121. As part of our project, we are in the process of certifying our device firmware using the LoRaWAN Certification Test Tool (LCTT) for the EU868 region.

Here are some details about our design:

• The LoRaWAN stack (v1.0.4) and radio layers are sourced from the LoRaMac-node repository.
• The LR1121 radio drivers are sourced from the SWSD003 repository.
• We have successfully implemented and tested LoRa and LoRaWAN functionalities on our custom hardware.

Issue Encountered During Certification

While performing LCTT certification, we are encountering challenges with tests involving FSK optional data rate packets:

• Observation 1: The Device Under Test (DUT) is unable to receive downlink FSK packets from the LCTT.
• Observation 2: The DUT successfully transmits uplink FSK packets, which are received correctly by the LCTT.

Debugging Findings

Upon further investigation on the DUT side, we observed the following:

1. The LR1121 module does not generate any interrupts (e.g., RX_TIMEOUT, RX_DONE, or RX_ERROR) when receiving downlink FSK packets during these tests.
2. All other tests in the certification process are passing without issues.
3. Even node to node communication in FSK mode also not working. Here we feel, the problem lies in Receiving configuration side.

Could you please assist us in identifying and resolving the root cause of this issue? Any insights into debugging steps or configurations specific to the LR1121 and FSK downlink reception in this context would be highly appreciated.

Thank you for your support.

[STTwo-32]

Hello @saikrishna 

The LE1121 is not an ST SubGHz component. So, if you are looking for any support concerning a certification process on this part, you may have to ask the owner of this component on his Community available on this link.

Best Regards.

STTwo-32