Join requests are being sent outside of the defined sub band. All of the data messages are sent in the correct sub band however. I can replicate the issue on the WLR089 Xplained board as well.
Some details about the setup:
MLS_SDK_1_0_P_5
End Device example project
@mrpackethead I’m wondering if there was any resolution with Microchip?
I think there are also issues with the frequency selection in ABP mode as well, but I didn’t have the RTL-SDR when I was fighting those issues.
I’m attaching a screenshot of 1 successive join attempts within SDRsharp. There were other join attempts outside the range, some far enough away to only see the noise surrounding them.
This is normal. Join Requests in US915/AU915 and CN470 are transmitted across all FSBs. Once the join is accepted, the Network Server instructs the device to disable all other FSBs than the configured one.
With ABP you need to hardcode all configuration, and make sure the configuration on your end device exactly matches the configuration in the Network Server. Do yourself a favor and just use OTAA which negotiates all that on/after join.
Yes, that’s what the LoRaWAN spec says should happen, though there are nodes that can be given a hint to use only the subband actually supported by a network such as TTN - which is non-standard and not future proof, but more efficient at the moment.
With ABP you need to hardcode all configuration, and make sure the configuration on your end device exactly matches the configuration in the Network Server. Do yourself a favor and just use OTAA which negotiates all that on/after join.
Ironically in US915/AU915 there’s no CFlist in the join accept, so apart from the RX window settings this has to happen afterwards using MAC commands which are also available in ABP anytime a server suspects they might not have the full configuration. The main thing that OTAA thus ends up doing there is making it certain that the server needs to configure the channel map. I was under the impression it tended to do so with ABP too until it got an ack for each of those MAC commands, but could be wrong on the current TTN server behavior.
Interesting @htdvisser, good to know. Thanks for the quick reply.
I’ve had ABP working in the past, but for the WLR089 I could only get it to work when selecting a region other than Australia. This then sent me towards using the CLI to get around the Nonce not being incremented and stored with each join attempt during firmware development. It can be a little annoying needing to do the join request multiple times, before being able to check if the updated code is functioning correctly. For a production unit with Backoff implemented it won’t really matter.
