optimizing nRF5340 Audio application for maximum range

[JeraDrson]

Hello,

I am working on unidirectional voice broadcasting device where the maximum range is the priority. At this time I am developing on Audio DK boards.

I need some help to choose the correct settings.

16KHz/16b, single stream (mono) quality is good enough, audio latency is not important

I need some few bytes short custom data advertisement about 5x per second. No other communication is needed.

I made some adjustments in nRF Kconfig GUI to select the audio format, audio works but it is hard to tell the the sittings is close to optimal (tested outdoor range is about 150m with optimal antenna orientation).

I understand setting the device to coded PHY should help, however I do not know how to do that.

I added

CONFIG_BT_CTLR_PHY_CODED=y

CONFIG_BT_EXT_ADV=y

CONFIG_BT_USER_PHY_UPDATE=y

to the prj.conf but i get message that CONFIG_BT_CTLR_PHY_CODED  was set to n because of dependencies. I could not find any related options in kconfig editor.

Also how can i determine the number of retransmissions?

Thank you

Regards Jeronym

[Amanda Hsieh]

Hi,

Which NCS version are you using?

I added

CONFIG_BT_CTLR_PHY_CODED=y

CONFIG_BT_EXT_ADV=y

CONFIG_BT_USER_PHY_UPDATE=y

to the prj.conf

Please try to add those configs to hci_ipc.conf.

Regards,
Amanda H.

[JeraDrson]

v 2.6.1

I moved the option to hci_ipc.conf (i tried it before).

I cleared the project, restarted to visual studio and i no longer see the dependencies issues. Is there a way to know ir is really working? Maybe some debug prints?

[Amanda Hsieh]

Then, your audio DK should support coded phy now. 

What is your other target, phone or another Audio DK? Do you also set coded phy on another board?

How do you measure the distance? Outdoor without building?

[JeraDrson]

The options are in nrf5340_audio/build/hci_ipc/zephyr even in unmodified project. I than add the 3 options to child_image/gci_ipc.conf.

To demonstrate i added check to main. Those options do not propagate to the preprocessor.

Does the same work on your size? Could you share your project?

I have 2pcs of DK. Of course i make the settings on both sides when i test range...

[JeraDrson]

Here is another picture that may explain something.

Options under nrf5340_audio/build/hci_ipc/zephyr/.config do not match the kconfig

[JeraDrson]

I did more experiments:

When I create new clean application i can find 

Bluetooth Controller (BT_CTLR) 

and inside

Coded PHY Support (BT_CTLR_PHY_CODED)

option in Kconfig GUI, however it does not build.

warning: ENTROPY_NRF5_RNG (defined at drivers/entropy/Kconfig.nrf5:14) has direct dependencies !ENTROPY_NRF_FORCE_ALT && DT_HAS_NORDIC_NRF_RNG_ENABLED && ENTROPY_GENERATOR with value n, but is currently being y-selected by the following symbols:
- BT_LLL_VENDOR_NORDIC (defined at subsys/bluetooth\controller\Kconfig.ll_sw_split:8), with value y, direct dependencies SOC_COMPATIBLE_NRF && !n && !n && BT_LL_SW_SPLIT && BT_CTLR && BT_HCI && BT (value: y), and select condition SOC_COMPATIBLE_NRF && !n && !n && BT_LL_SW_SPLIT && BT_CTLR && BT_HCI && BT (value: y)

error: Aborting due to Kconfig warnings

This is all very confusing.

I need someone to test the Audio Application with coded PHY enable option.

[Amanda Hsieh]

Hi, 

Sorry for the delay. 

I have checked with the team and got

Unfortunately, we might not be able to support coded PHY properly at this moment.

Since coded PHY will need more time to transmit an encoded frame, we cannot use the 10ms ISO interval. However, all of our audio datapath is designed for the 10ms ISO interval. We are working on it, but no schedule promise. 

Regards,
Amanda H.

[JeraDrson]

Thank you for the investigation. We can design the prototypes of the product without coded phy and update it later (hopefully it will be ready in few months). Can I get some notification when this feature will be ready?

[Amanda Hsieh]

Please contact our regional sales manager on this requirement or Use the sales-related questions on contact us:
https://www.nordicsemi.com/About-us/Contact-us