NUCLEO WL55JC1 P2P(GW) Support and LoRaWAN Node Capacity

[Deep23]

Hello,

We are currently working with the NUCLEO-WL55JC1 board for LoRa communication and have a few technical queries.

1. STM32WL as Gateway / P2P Receiver
We are planning to use two NUCLEO-WL55JC1 boards, where:

• One board will act as a LoRa end node

• The other board will act as a gateway or P2P receiver

• Is there any gateway or P2P receiver firmware example available in the STM32WL SDK for the NUCLEO-WL55JC1 board?

2. LoRaWAN Gateway Capacity

We would also like to understand the theoretical number of end nodes that can be supported by a single LoRaWAN gateway under the following conditions:

 

• Payload size: 16 bytes

• Spreading Factor: SF10

• Uplink transmission interval: 1 hour per nodeAny calculation method, reference document, or guideline from your side would be very helpful.
  
  

 

[Erlkoenig]

You can't use a STM32WL55 as a compliant LoRaWAN gateway, as a gateway needs to be able to listen to all SFs simultaneously. With a STM32WL55 or any SX126x you can only build a non-LoRaWAN-compliant "custom" gateway.

Have a look at the "SubGHz_Phy_PingPong" or "SubGHz_Phy_Per" examples in STM32CubeWL; you can easily change the modulation from FSK to LoRa.

Using the TTN airtime calculator you can see that one 16 B packet at SF10 (BW125 assumed for EU868) is 411ms, so that leaves time for theoretically over 7000 messages per hour and therefore 7000 nodes. However factoring in downlinks (particularly for ADR) and the time gap for that I probably wouldn't use more than ~1000. This is assuming all nodes have perfect time synchronization and transmit in a specifically chosen time slot.