Advertising via coded PHY

RE: Advertising via coded PHY

Vidar Berg — Fri, 23 Jan 2026 12:38:55 GMT

Thanks. I got this feedback from one of the developers in response the parameters you used:

Change parameters to BN=2, NSE=2, double their current iso interval (keep SDU interval the same). Note, this will increase the latency but improve amount of air time available. This could be increased further if latency is not an issue e.g. BN=3. NSE=3. triple the current iso_interval, BN=4, NSE=4, four times the iso_interval...
Change the advertiser to use coding=s2 if this is acceptable to the customer. Unfortunately, we do not currently support s2 on BIG

RE: Advertising via coded PHY

gab987 — Wed, 21 Jan 2026 11:24:29 GMT

Hey, sorry for the late response.

I used different values for the broadcast parameters where i changed values like .num_subevents, .irc and .pto in the bt_iso_big_create_param and bt_iso_chan_qos structures.
On coded phy i only tested values where .irc = .pto = .nse = 1 and .pdu = .pdu is on of 30/40/80.

RE: Advertising via coded PHY

Vidar Berg — Tue, 30 Dec 2025 13:30:10 GMT

I checked with the developers, it turns out you can have a valid BIG that uses all the airtime from the advertiser without HCI error. Could you please provide us with the parameters you are using for the broadcast source?

RE: Advertising via coded PHY

gab987 — Thu, 18 Dec 2025 10:28:53 GMT

And yes, i was able to find the advertisement when no stream was running.

RE: Advertising via coded PHY

gab987 — Thu, 18 Dec 2025 10:27:25 GMT

No, i did not make any progress.

I started out using the zephyr/bap_broadcast_(source/sink) samples and modified them.

RE: Advertising via coded PHY

Vidar Berg — Tue, 16 Dec 2025 14:56:02 GMT

Sorry for the delay. Have you made any progress on this in the meantime? If not, could you point me to the exact SDK samples you used as a starting point?

[quote user="gab987"]When the stream is started immediately after the advertisement is started the receiver cannot find the advertisement.[/quote]

Does this mean that it works with coded PHY when the stream is not started?

RE: Advertising via coded PHY

gab987 — Thu, 04 Dec 2025 10:07:36 GMT

I just checked on the logs for the bis source app + controller and the bis sink app + controller and there are no error messages. The controller just spits out the `hci_ipc: Sent/Received messages of x bytes.` and the app does not print any error/warnings and does not return any error values.

RE: Advertising via coded PHY

Vidar Berg — Thu, 04 Dec 2025 09:15:17 GMT

If you have not already, please enable logging to help catch any errors reported by the controller and app. The controller should give an error if there are issues with the configuration.

RE: Advertising via coded PHY

gab987 — Wed, 03 Dec 2025 17:46:48 GMT

I think I found the combination of issues. For context I am trying to send/receive Broadcast isochronous streams.

I added the `CONFIG_BT_CTLR_PHY_CODED` and `CONFIG_BT_EXT_ADV_CODING_SELECTION` to the `prj.conf` of both controller, which is weird, since i was able to create/connect to BIS on the coded PHY without those options
I introduced a delay on the broadcast source source between the start of the periodic + extended advertising and the creation of the BIG. I think the receiver cannot find the advertisement when the source is streaming. When the stream is started immediately after the advertisement is started the receiver cannot find the advertisement.

RE: Advertising via coded PHY

Vidar Berg — Wed, 03 Dec 2025 13:58:05 GMT

Hi,

Do you have logging enabled to see if bt_le_scan_start() returning an error code or not? I would also recommend you have a look at the central_hr_coded sample in the SDK to compare the configurations.

Best regards,

Vidar