Dowlink to class C device issues

ChirpStack Application Server
1

I’ve an application running with class C devices and ABP joining method. End-nodes are installed in mobile devices and they can switch between gateways. So far, it is deployed and working but I would appreciate some help to overcome some problems I’m facing.

  • I cannot send dowlinks thorugh gateways if they have never received and uplink from that device. Right now, I’m forcing a first time uplink but I would like to avoid this since can cause some troubles for the application.
  • Similarlly, when using multicast, gateways are not sending downlinks unless they consider they have at least one device around.

I know the way we have implemented the system is not the most standard one but it cannot be changed, at leat, power comsumption is not and issue.

2

Unfortunately, this is just how Chirpstack works. Since the algorithm for deciding what gateway to send the downlink to is based off the RSSI and SNR of the device’s uplinks, without the uplink first Chirpstack cannot decide what gateway to queue the downlink in.

I think it would take serious reworking of the downlink code to change this.

3

Yes, I imagined it wouldn’t be that easy.