Channel sounding using multiple reflectors

[psychogenic]

I am attempting to do channel sounding with one initiator and two reflectors.  Switching between reflectors, by connecting to each in turn, does work, but it is very slow.

I have tried both

• connecting to both, enabling channel sounding at the time of connection and leaving it enabled
• connecting to both, enabling and disabling channel sounding with one reflector connection at a time

Both methods lead to successful sounding at the time of connection, but from the point where there have been CS events between the initiator and the second reflector it only ever works with the last connection made, and infinite aborted sub-events with the first device connection, basically getting a subevent_done_status of  BT_CONN_LE_CS_SUBEVENT_ABORTED with the reason being declared BT_CONN_LE_CS_PROCEDURE_ABORT_CHMAP_INSTANT_PASSED.

What is this error, why is it happening?  More importantly, what would be the steps to enable rapid switching or simultaneous CS with two reflectors?

I had some hope that the question posed on  channel sounding cs channel map update instant passing would give some info, but 3 months later Swathy's update is still pending. 

[Simonr]

Hi Pat

Sorry about the late reply here. I have had a look around and can't find a good explanation on this, other than it being that the channel map instant passed before the subevent completed. I think this could be due to the channel mapping on both reflector using the same channel map, so they are blocking each other. I guess you can try using different channel maps for the two so they don't overlap.

I have forwarded this request to the developers now, and will update this ticket when I hear something. Unfortunately it seems like the case you linked to fell through our cracks over the summer vacation period, and I'll try to kickstart that again as well.

Best regards,

Simon