When running the channel sounding example on the nrf54l15, how can one obtain the IQ values of the ranging signal?

[a9876]

When running the channel sounding example on the nrf54l15, how can one obtain the IQ values of the ranging signal?I want to obtain the IQ value and then use my own algorithm to calculate the distance.

[Edvin]

Hello,

I am not 100% certain it is possible to increase it much more. Channel sounding requires a lot of radio activity, which takes a bit of time. 

Can you, however, upload what you currently have? Then I can have a look, and try to tweak some CS parameters, to see if it is possible to speed it up. 

Best regards,

Edvin

[a9876]

channel_sounding_ras_initiator.rarI am using version 3.0.2 of ncs. The code is shown in the attachment. Thank you, Edvin.

[Edvin]

Hello,

Can you please try the following:

Decrease this:

https://github.com/nrfconnect/sdk-nrf/blob/main/samples/bluetooth/channel_sounding_ras_initiator/src/main.c#L741-L742

Decrease the ACL interval:

https://github.com/nrfconnect/sdk-nrf/blob/main/samples/bluetooth/channel_sounding_ras_initiator/src/main.c#L555

Note that if you decrease the procedure interval by "too much" there will probably not be enough time for the RAS (Ranging service) to relay the CS measurement data from the rrsp to the rreq before the next proedure starts. This will lead to dropping some of the procedures, and perhaps an effictively reduced rate of new distance estimates.

One option to combat this issue is to reduce the amount of CS measurement data of CS measurements data per CS procedure. Note that this will always be at the cost of reduced accuracy. This could be done in a dew different ways.

Reducing the number of enabled channels in the channel map by settting fewer bits here:

https://github.com/nrfconnect/sdk-nrf/blob/main/samples/bluetooth/channel_sounding_ras_initiator/src/main.c#L719

Reducing the subevent length (1) and configuring the max_procedure_len subevent len (2)

(1) https://github.com/nrfconnect/sdk-nrf/blob/main/samples/bluetooth/channel_sounding_ras_initiator/src/main.c#L744-L745

(2) https://github.com/nrfconnect/sdk-nrf/blob/main/samples/bluetooth/channel_sounding_ras_initiator/src/main.c#L740

Configuring the submode as unused here:

https://github.com/nrfconnect/sdk-nrf/blob/main/samples/bluetooth/channel_sounding_ras_initiator/src/main.c#L705-L707

(this may reduce the security of CS)

Best regards,

Edvin