Adaptive frequency hopping with Bluetooth LE audio broadcast

[MKir]

We are evaluating the nRF5340 chip for a Bluetooth LE audio broadcast streaming application.

Is it possible to use adaptive frequency hopping with the BLE audio network core image? If yes, how to do it with the audio sample?

[SwRa]

Hi Miklos,

This is what I heard back from the developers: 

AFH is a term that is only used in the context of BR/EDR support mode only.

Are you looking for Host Channel Classification being done by the Host stack? Or do you want an application from us for it? Both are not currently supported in upstream zephyr Bluetooth host stack or any samples, respectively.

Best Regards,

Swathy

[MKir]

Dear Swathy,

I was asking with this wording because a potential customer came to us with a requirement to "meet ETSI 300 328 requirements for Adaptive Mode" to allow for +20 dBm EIRP. They also explicitely spcecified "support for adaptive frequency hopping" with LE channel selection algorithm #2.

I believe this is what is described in the core specification as channel classification on the LE link layer and channel selection algorithm #2. I am interested in the implementation status of the controller's autonomous channel classification (and channel selection), not the host channel classification. Specifically, the implementation status in the BLE audio network core image.

Vol. 6 Part B of the core specification states the following:

4.4.6.8 Channel indices
Each packet containing a BIS PDU shall be transmitted on the channel index
specified by Channel Selection Algorithm #2 (see Section 4.5.8.3)

4.5.8.1 Channel classification

(different in spec version v5.2 and v5.3/v5.4, this is the content from v5.4)

The Link Layer can classify the general-purpose channels as being unknown,
bad, or good. These classifications are determined individually by the Link
Layer based on local information (e.g., from active or passive channel
assessment methods or from the Host). Information received from other
devices (e.g., via an LL_CHANNEL_MAP_IND) shall not be included in the
channel classification. The Host may provide channel classification information
to the Link Layer. The Link Layer may use the information provided by the
Host.

Kind regards,

Miklos