Dear Rack team,
In this question, I understand that LBT for LoraWAN is V4.0.0.
When do you plan to support LBT for P2P?
CAD or LBT (not sure what will be used) is on the list for the next RUI3 version.
Basically they do the same, but with different methods.
CAD - Channel Activity Detection - is listening on the requested send frequency for any activity and returns whether the frequency is in use or not.
LBT - Listen before Talk - is checking the RSSI levels on the requested send frequency to see if there is any activity.
I think the LoRaWAN stack implemented LBT because not all LoRa transceivers support CAD (I know the SX1262 supports it)
beegee Thank you for your reply.
Will LBT support in this way?
Sorry for the Japanese site.
If my Google translation is correct:
It supports the LBT (Listen before talk) function. LBT refers to how a device enters Rx mode and checks for interference signal levels before it starts transmitting.
That is exactly how we are implementing LBT.
I see in the latest firmware release for RAK3172 (4.0.6) with the AT+CAD command added.
Please, do you already have the documentation for this new command?
Documentation is not yet online.
Activate CAD with AT+CAD=1.
Send packet with AT+PSEND=303132
If CAD finds channel actrivity, it will return an error, otherwise it will return +EVT:TXP2P DONE
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@beegee very good!
Is the CAD setting stored in Flash or it is necessary to set on every system startup?
The AT+PSEND=303132 was only an example, right? I expect it will work with any payload…
Thank you
I have to check whether you need to activate CAD only once. I am not sure.
The AT+PSEND is just an example, you can use any payload.
I tested here, it is stored in flash.
Does the CAD insert any delay in the communication or it should be not relevant?
For sure there is a short delay, as the device is first listening on the send frequency for any activity.
I didn’t make any measurements regarding the delay.