ADR issue - DR not changing from SF7 to SF12 as distance is increasing

ChirpStack Network Server
1
  • I am using Chirpstack v3 with Kerlink iFemtoCell evolution gateway and I am using OTAA.
  • When device is rejoined at SF12, as the distance between gateway and node reduces, the DR changes from SF12 to SF7.
  • But when the device rejoined at SF7, with the increasing distance, the data rate never adapts to greater spreading factors.
  • I have enabled ADR on both end-node and Chirpstack.
  • What could be the issue?
2

Hi @RonNad,
There is probably no issue. Default ADR never decrease DR (or increase SF if you prefer) to avoid cascading effect on the network. But it can increase DR (or decrease SF).
Other fact to consider: if your device joins on SF7 and is going out of range from the network, whatever the ADR is, it will never receive the MAC commands to change SF (except if it rejoins periodically or after unsuccessful ACK).
So if your devices are moving, you should not use ADR.

2 Likes
3

Your device should implement ADR backoff strategy to overcome this issue.

See: Implementing Adaptive Data Rate (ADR) | DEVELOPER PORTAL

2 Likes