Channel Sounding Synchronization Mechanism and Application

RE: Channel Sounding Synchronization Mechanism and Application

cheng — Sun, 22 Jun 2025 09:04:07 GMT

Thanks!

RE: Channel Sounding Synchronization Mechanism and Application

Asbjørn — Fri, 20 Jun 2025 09:30:01 GMT

Hi,

it's done at connection establishment as you see. Since it is two Nordic devices, it is not retriggered by default. Mode-0 step is still present, but not renegotiated.. I'd expect you to see different output if you were connected to a different vendors reflector.

Bestregards

Asbjørn

RE: Channel Sounding Synchronization Mechanism and Application

cheng — Tue, 17 Jun 2025 08:55:54 GMT

Hi Asbjon,

I can see this output. Is this the output after mode-0 has finished executing?
I am currently using two nRF 54L15 devices. I only see this output during the connection establishment, and for each subsequent subevent measurement, the results are output directly.
In each subevent, is the mode-0 step also present? According to the protocol, mode-0 must be executed at least once at the beginning of every subevent.

Best,
Cheng

RE: Channel Sounding Synchronization Mechanism and Application

Asbjørn — Wed, 11 Jun 2025 13:09:03 GMT

Hello Cheng,

Are you logging any output from the nRF54L15 during this on the RTT? There should be a statement in the beginning on the connection that says "CS capability exchanged completed" or along those line. That would be the indication that the exchange has happened and then the next phase of the measurement is done with multiple packages sent and reflected.

Best regards

Asbjørn

RE: Channel Sounding Synchronization Mechanism and Application

cheng — Tue, 10 Jun 2025 15:59:54 GMT

Hi Asbjørn,

Thank you very much for your reply.

When I run channel sounding tests using two 54L15 development boards, how can I confirm whether mode-0 is enabled? In nCS 2.9.0/3.0.0, the minimum step number for mode-0 is 1, which means it should be executed at least once at the start of each subevent. If both sides are using nRF54L15, is it possible that nothing actually happens during mode-0? I’m not sure if my understanding is correct.

Regarding the register I mentioned, it can be found in the nRF54L15 Product Specification (https://docs.nordicsemi.com/bundle/ps_nrf54L15/page/radio.html#ariaid-title159). After reviewing the documentation again, it seems that CSTONES.FFOSET is more relevant for frequency offset measurement.

Best regards,
Cheng

RE: Channel Sounding Synchronization Mechanism and Application

Asbjørn — Fri, 06 Jun 2025 12:06:08 GMT

Dear Cheng,

For nordics implementation we support using mode-0 synch, but it is no necessary. This is sometimes referred to as CS without Frequency Actuation Error (FAE). Essentially, it means the initiator transmits on the frequency specified by the channel number without any further frequency adjustments. This can be beneficial for simplifying the ranging process and ensuring consistency across different devices. It can be enabled on Nordic if needed by the other end of the ranging.

I'd encourage you to have a look at Bluetooth SIG own technical summary of the spec 6 features, including channel sounding here: https://www.bluetooth.com/core-specification-6-feature-overview/

To keep the synch you would have to re-synch as they will drift compared to each other.

CSTONE.PCT, where are you finding this register? Are you able to share some link to what you are referring to?

Best regards

Asbjørn