There are two sources of packet loss- low SNR and collisions. The NbTrans calculation makes sense for low SNR nodes, but only escalates the problem in busy networks. I think this is the source of our problem. We will be deploying a network inside larger commercial buildings, and though we are working to reduce the LoRa transmissions to a minimum, there will be times where we have high packet rates.
For networks with a high probability of collisions, it would be very good to limit the ADR NbTrans setting.
Periodically LoRaServer (3.0.2) is ramping the NbTrans count from 1 to 2 to 3 in two separate back-to-back uplinks. During this time, the RN2903 returns only mac_err for any transmission attempt. Then inexplicably LoRa ramps NbTrans back down to 2 then to 1, in about 1 second.
We have verified the packet loss is currently less than 5%.
- Most importantly, is there a way to limit NbTrans to 1.
- Why is this happening? (And what information do I need to supply? Capturing packets is difficult because the LoRa Server portal eventually stops responding after not too many packets)