Dwell time for AS923 frequency plans

TTN Network and Services The Things Stack v3
1

Hi all,
I’m testing my devices with AS923_x in The Things Stack Sandbox.
I understand there is optional Dwell Time for AS923_x.

For AS923 Group 2, there are 03 options in Frequency Plans | The Things Stack for LoRaWAN

  1. Asia 920-923 MHz (AS923 Group 2) with only default channels
  2. Asia 920-923 MHz (AS923 Group 2) with only default channels and dwell time disabled
  3. Asia 920-923 MHz (AS923 Group 2) with only default channels and dwell time enabled

Option 2 and 3 are easy to understand.
What does option 1 mean? Option 1 means no dwell time settings or dwell time disabled? How is Option 1 different from Option 2 and 3?

Could you help to advise me?
Thanks a lot and have a nice day.

2

Interesting question. Some observations:

  • The frequency plans from the dropdown selection when registering a device are listed here.
  • For e.g. US915 which has uplink dwell time limitations, there is a section with these rules listed:
    dwell-time:
  uplinks: true
  downlinks: false
  duration: 400ms
  • For e.g. EU868 which has no dwell time limitations, there is no mention of dwell time in the corresponding file. So I guess an absence of the section above means that TTS will not apply dwell time limitations.
  • If we look at the main list again for e.g. AS923_2, there are indeed three entries:
    - id: AS_923_2
  band-id: AS_923_2
  name: Asia 920-923 MHz (AS923 Group 2) with only default channels
  ...
  file: AS_923_2.yml

- id: AS_923_2_NDT
  band-id: AS_923_2
  name: Asia 920-923 MHz (AS923 Group 2) with only default channels and dwell time disabled
  ...
  base-id: AS_923_2
  file: disable_dwell_time.yml

- id: AS_923_2_DT
  band-id: AS_923_2
  name: Asia 920-923 MHz (AS923 Group 2) with only default channels and dwell time enabled
  ...
  base-id: AS_923_2
  file: enable_dwell_time_400ms.yml
  • AS923_2 base file does not include any mention of dwell time, just as for EU868.
  • disable_dwell_time.yml contains the lines similar to US915 (but disabled), just like enable_dwell_time_400ms.yml does.

Given that this additional file that we can see for DT and NDT is not listed for the ‘normal’ AS923_2, I’d suspect it works similar to EU868 for which these lines are also absent, implying there are no dwell time limitations. But that makes one wonder why this first option exists… :man_shrugging: I guess that’s something to ask on Slack.

1 Like
3
  1. Asia 920-923 MHz (AS923 Group 2) with only default channels
  2. Asia 920-923 MHz (AS923 Group 2) with only default channels and dwell time disabled
  3. Asia 920-923 MHz (AS923 Group 2) with only default channels and dwell time enabled

Thanks a lot for your response.

May be later I use RAK3172 to test with TTS.
The interesting of RAK3172 for AS923_x is

  • The default Dwell time is true in the source code of the device.
  • It will set Dwell time after join based on MAC commands from server.

So based on your reply, now I suspect there is difference between Option 1 (not mention DwellTime) and Option 2 (DwellTime disabled).

In Option 1, there would be no DwellTime setting in MAC commands, so RAK3172 will keep the default DwellTime (in this case is true).
In Option 2, RAK3172 will set DwellTime to false.
In Option 3, RAK3172 will set DwellTime to true.

Let me have some time to test the theory.

4

I would agree indeed. You should also be able to test this with RadioLib with debug mode enabled if you squint your eyes :wink: (or send me logs), but sure try it out with a RAK device :+1:

1 Like
5

Ok, I will do the test with RadioLib this weekend.