Hi,
We are experiencing an issue with downlink ACK reception on LoRaWAN devices using Mesh gateways with ChirpStack.
Current configuration :
- RX Delay set to 12s in the Device Profile
- Network: ChirpStack + Mesh gateways
- Uplinks are correctly received
- Downlink acknowledgements are never received by devices
Issue:
- Even with RX Delay configured to 12 seconds in the Device Profile, devices never receive any ACK downlinks.
Questions:
- Are there other ChirpStack parameters (Network Server, Application Server, Gateway Bridge, etc.) that affect RX1/RX2 delay timing?
- Are there any specific settings on the Mesh gateways (buffering, latency, scheduling, time sync, mesh routing, etc.) required for LoRaWAN downlinks?
- Are there known constraints between:
- High RX Delay values (12s)
- Downlinks
- Mesh gateways
- ChirpStack
Possible causes we are investigating:
- Mesh latency incompatible with RX windows
- Time synchronization issues (NTP / GPS / PPS)
- Downlink generated by ChirpStack but never transmitted by the gateway
- Mesh network downlink scheduling problems
If anyone has already faced this setup (Mesh gateways + ChirpStack), any feedback or experience would be highly appreciated.
Thanks in advance for your help
Please note that changing the RX1 Delay in the device-profile only becomes effective after ChirpStack has sent a mac-command to the device, and the device confirms this mac-command. Please check the delay field in the downlink payload in ChirpStack if the downlink is using 12s or 1s.