BLE Channel Sounding - changing the number of samples.

[Vinay Bhagure]

I am testing out the Bluetooth Channel sounding sample with the nRF54L15-dk board using the samples of Channel sounding Initiator with ranging requester. How to change the number of samples in the round trip timing method and phase based ranging method. 

 

[Erik Sandgren]

Hello, 

Not sure if this is what you are looking for, but one way of changing the ratio of main mode to sub mode steps is by changing these two values https://github.com/nrfconnect/sdk-nrf/blob/509fa66004370f00faf13912cc6fced25dda6d6c/samples/bluetooth/channel_sounding_ras_initiator/src/main.c#L423-L424
For example if I change both to 1, I get roughly as many sub mode steps (RTT steps in this case) as I get main mode steps (PBR steps in this case). Example log from the sample with this change:

I: Estimated distance to reflector:
I: - Round-Trip Timing method: 4.592482 meters (derived from 78 samples)
I: - Phase-Based Ranging method: 0.434500 meters (derived from 79 samples)

[Vinay Bhagure]

Thankyou. That was exactly what I was looking for. But event if we change the number of samples, there is inconsistant and inaccurate values from RTT and PBR methods. It might take some time for Nordic to develop a consistant working solution for this. 

[Edvin]

Indeed this is not the final solution for the channel sounding. It is currently just a proof of concept, as I mentioned, to show that we can fetch the raw data correctly. 

Best regards,

Edvin

[Vinay Bhagure]

Is there any way to combine both the distances from RTT and PBR methods and get the average solution for the distance measurement?

[Edvin]

In this sample, you would have to do that in your application. I guess it is just some simple maths, but you need to decide how you want to weight them. If you weight them equally, just add together all measurements times the number of samples used, and divide by total samples. 

But again, neither of these are good measurements at the moment. My best advice is to wait for the sample to get some smart algorithms that actually gives decent results.

Best regards,

Edvin

[Vinay Bhagure]

Thankyou Edvin!