How to get high qulity IQ data in Channel Sounding?

RE: How to get high qulity IQ data in Channel Sounding?

Simonr — Mon, 01 Dec 2025 10:26:22 GMT

Can you create a separate ticket explaining your issue in detail? And is the actual range you take measurements from up to 40 meters in this case, or closer to 1-5 meters?

Best regards,

Simon

RE: How to get high qulity IQ data in Channel Sounding?

witc — Fri, 28 Nov 2025 13:04:16 GMT

Is the fix already merged in to the main branch of ncs?
Not sure if that fix could resolve my problem: IFFT method works really bad.

The label Fused is basically RTT method:

RE: How to get high qulity IQ data in Channel Sounding?

Simonr — Tue, 11 Nov 2025 09:47:20 GMT

A fix has now been implemented to cover the FFT implementation issue you reported. It is a part of this pull request if you're interested: https://github.com/nrfconnect/sdk-nrf/pull/25480

Best regards,

Simon

RE: How to get high qulity IQ data in Channel Sounding?

Simonr — Wed, 05 Nov 2025 08:49:51 GMT

Hi again

I got some replies overnight.

1. FFT implementation: This seems to in fact be a bug on our side, and we're currently investigating. I'll keep you updated. Thank you for making us aware.

3. IQ data evaluation: We suggest trying to increase the T_PM using the following Kconfig option https://github.com/nrfconnect/sdk-nrf/blob/005f9d544cdcbe7376a537aed7424137923e88a5/subsys/bluetooth/controller/Kconfig#L649-L684. The T_PM is the duration of each tone measurement within the mode 2 and 3 steps in channel sounding. Our default is 10µs which is the minimum allowed by the specification.

Best regards,

Simon

RE: How to get high qulity IQ data in Channel Sounding?

Simonr — Tue, 04 Nov 2025 13:27:45 GMT

Hi Qianjunwang

1. This is a design choice, and I need to ask the developers why this decision was made. I can't guarantee I can provide a straight-forward answer.

2. We are continuously working on improving our algorithm, but I'm not aware of any specific things improving this. If you have suggestions we're open to them.

3. Not that I'm aware of, but I will ask the developers about this as well.

I'll get back to you on Friday at the latest with an update from our developers or at least a progress update. Thank you for your patience.

Best regards,

Simon

RE: How to get high qulity IQ data in Channel Sounding?

Susheel Nuguru — Mon, 03 Nov 2025 09:31:47 GMT

Hi,

The person who can answer this is away today, he is back hopefully tomorrow. I appreciate your patience in advance.