Multi-initiator Channel Sounding – best practice for fast distance updates (indoor tracking)

RE: Multi-initiator Channel Sounding – best practice for fast distance updates (indoor tracking)

Edvin — Fri, 19 Dec 2025 13:06:57 GMT

Please note that DevZone will be short staffed for the next two weeks. Please expect some delayed response. I am sorry for the inconvenience.

Best regards,

Edvin

RE: Multi-initiator Channel Sounding – best practice for fast distance updates (indoor tracking)

Edvin — Fri, 19 Dec 2025 13:05:46 GMT

I can't guarantee that you can manage every 3 seconds for each initiator.

It is a good idea, in this case, that you have many initiators and only one reflector. This distributes the CPU payload among the 5 initiators, instead of having the tracked device handle it all.

One recommendation that we have is that you consider making the reflector the BLE central in the connections. This way, the reflector/central will have control of all the connection timings, and you are much less prone to BLE timing issues. The initiators/peripherals can still initiate the channel sounding measurements.

So the first task would be to flip around on the default peripheral/central behavior.

Please see the application that I uploaded in this reply from the 11th of September, which does pretty much that. Then the next task would be to add more peripherals and have them connect to the same central.

Best regards,

Edvin

RE: Multi-initiator Channel Sounding – best practice for fast distance updates (indoor tracking)

Andygb40 — Fri, 19 Dec 2025 06:51:54 GMT

Hi Edvin, the devices would be in a one to many configuration where the one is the reflector. The maximum number of initiators planned is five, I’m not concerned about battery life at present as I already get a week and we only want one day of use between charges. The update frequency can be quite slow, maybe each device updating every two to three seconds.
Thanks

Andrew

RE: Multi-initiator Channel Sounding – best practice for fast distance updates (indoor tracking)

Edvin — Thu, 18 Dec 2025 22:03:51 GMT

Hello,

This very much depends on how you set up your devices. What devices that are battery powered vs. mains powered. How often do you plan on updating the measurements, and so on.

Perhaps you can give a brief explanation on what sort of use case you imagine. One-to-many? Many-to-many? Which devices has the smallest battery? And how often do you plan on taking new channel sounding measurements?

Best regards,

Edvin

RE: Multi-initiator Channel Sounding – best practice for fast distance updates (indoor tracking)

Andygb40 — Thu, 18 Dec 2025 20:28:51 GMT

I’m also looking into the possibility of connecting multiple initiators to one reflector. I haven’t made a lot of progress as yet, so was wondering if anyone here would be able to share some insight or code they have on how to manage the connections.

RE: Multi-initiator Channel Sounding – best practice for fast distance updates (indoor tracking)

Fhar — Fri, 24 Oct 2025 10:04:08 GMT

Hello Thanos,

I just wanted to ask you about the changes you made to the Nordic sample to connect two initiators. I’m trying to do the same, but I can’t seem to get data from both initiators — only from one at a time, after resetting one of them.

Thank you very much for your help!

RE: Multi-initiator Channel Sounding – best practice for fast distance updates (indoor tracking)

PaKa — Tue, 09 Sep 2025 01:52:29 GMT

To add to Edvin's comment: if you try to track more than one moving device then you are much more likely to run into scheduling conflicts. Longer connection intervals with lower duty cycles will make this easier to handle. This is given by the technology since you have to be in a connection to range and trying to keep multiple connections that are anchored in time by different devices will always be more difficult.

RE: Multi-initiator Channel Sounding – best practice for fast distance updates (indoor tracking)

Edvin — Mon, 08 Sep 2025 13:33:16 GMT

Hello,

Just to be clear,

You want to measure the distance between one moving device and 3 stationary devices, right?

In that case I suggest what PaKa says. Make the moving device the central in the BLE connection, and also the reflector. The reason for it being the central is so that it controls the timing of the BLE connections (which would not be the case if it was the peripheral in the connection). The reason it is the reflector is because it is a simpler task, not requiring so much CPU time. This way it would spread out the workload on the stationary devices, which only needs to keep track of one distance each. It will also save power on the moving device, as this is most likely battery powered (where the stationary devices could be mains powered?)

Best regards,

Edvin

RE: Multi-initiator Channel Sounding – best practice for fast distance updates (indoor tracking)

Thanos Vasiloglou — Sat, 06 Sep 2025 17:18:13 GMT

Do you have any updates on my problem ?

RE: Multi-initiator Channel Sounding – best practice for fast distance updates (indoor tracking)

Thanos Vasiloglou — Mon, 01 Sep 2025 11:52:02 GMT

I will face the same problem when i add more initiators then ( more than one moving tags) . I am not thinking of scaling it to large tag numbers but at least i want to be able to process 3 initiators for a moving reflector. Is there a suggested stable way to do that ?

RE: Multi-initiator Channel Sounding – best practice for fast distance updates (indoor tracking)

PaKa — Mon, 01 Sep 2025 11:36:41 GMT

Make the reflector the central and the initiators the peripherals. This allows the reflector to handle the scheduling of all the links so less likely to have overlaps and lost packets due to this.