Concurrent channel sounding procedures

[Triscuit]

Hi,

I am trying to create a trilateration system with 3 initiators and 1 reflector (Hopefully multiple reflectors in the future) on the nrf54l15. The channel sounding with range requestor sample code demonstrates a one to one connection, but I modified the reflector logic so it keeps up to 4 connections in an array. When I run channel sounding with just one to one connection everything works perfectly. When I try to connect two initiators they both connect but usually only one initiator is able to receive the distance data, the other one just keeps displaying "tried to parse empty data", but once in a while they would both receive data, and sometimes they both don't get data. I am not sure what the issue really is. I thought about the reflector not having enough buffer but I turned it up already in the config file. Could this be a hardware issue? Is it just interference or maybe the sample code just cannot handle concurrent connections? I only saw one other post about concurrent connections and they only got it in sequential order. Any advice is appreciated as I cannot really progress at this point, thanks!

[Elfving]

Hi and sorry about the delay on this one,

Please let me if these requests are urgent for you. Any update on this from your side?

Triscuit said:

Do you know if sequential would work if I enable and disable channel sounding procedure instead of connect and disconnect the devices?

Sounds like this would keep the connections and avoid the main issue, which is scheduling conflicts between the different CS procedures- And I agree that keeping the connections alive would be faster. I guess there could also be conflicts between the CS procedures and other normal connections but I haven't heard of that being a problem. I can check with the relevant team.

Triscuit said:

My only idea is that it might be due to the sdc not being optimized to keep multiple connections alive as well as perform channel sounding procedure.

I'll ask with the team about this. Is sequential what you are currently going for?

Regards,

Elfving

[Triscuit]

Hi Elfving,

I tried the sequential method where I simply just enable and disable channel sounding as well as connect and disconnect, but they all won't work unless I reboot the reflectors. Perhaps I did not shut down the procedure properly? But even when I disconnect and try to connect again, they fail to connect. I had a reply from another dev and they said to use the recycle callback but even that did not work. I am not sure what rebooting does that disconnecting and connecting don't do. 

Could you ask the team if the issue with concurrent is because of the scheduling conflicts in the sdc please? It is my ultimate goal to do it concurrently, but right now I have to settle for sequential where I connect, disconnect, and then reboot each reflector every time I disconnect. Thank you so much for your time.

Sincerely, 

Triscuit

[Elfving]

Triscuit said:

Could you ask the team if the issue with concurrent is because of the scheduling conflicts in the sdc please?

Yeah, this is the case. Not because that there necessarily is a scheduling conflict, but that there scheduling conflicts might happen. I've also now learned that it can happen between CS and normal connections as well, which would explain why there would still be issues with just one device doing CS at the time and the other connections just waiting. It might be that rebooting does something with the connection priorities, making these conflicts less frequent.

It seems that making a new connection for CS each time is the only way of making sure that you are not running into a scheduling conflict at the moment. I'll ask the team about your specific scenario. 

Regards,

Elfving

[Hareesh123]

I tried the way you told . Its not working to concurrently get the data. Only when I press reset I am switching to the next board any way to resolve this

[Elfving]

Hi,

I might be misunderstanding you here but doing it sequentially is what we currently support.

Regards,

Elfving