Channel Forcing and Configuring Channel Selection Algorithm

[Yash.P]

Hello Nordic Support Team,

I have three queries to make. 

• Is it possible to force the channel in which the data transmission is happening using nRF52840 DK. 

To explain more, I am implementing a UART Communication with nRF DK and connected to a mobile phone and capturing the data using a Dongle. I am seeing this regular channel hopping(FHSS) mechanism of BLE. Instead of that, I'd like to force the data to be transmitted in one channel even if there is interference.

• The next is I would like to configure the Channel Selection Algorithm, I guess we have the feasibility to do so.
• Finally, I want to know whether it is possible to configure the channel hopping sequence or is there any relation with CSA to it?

Thanks in advance!

[Edvin]

Hello,

No, it is not possible to set a BLE device to use only one single channel. It is against the Bluetooth Specification. I don't have the number from the top of my head, but I believe that you need to use 15 channels in your channel map. 

So you will not be able to do this using our SoftDevice Controller (Bluetooth stack). Zephyr's bluetooth stack is open source, so in theory you can do anything there, but in the end, a peripheral (which is the usual role for the nRF) can only request channel map updates. They are then accepted or declined by the central (the phone, typically). 

If you were the central in the connection, however, and the phone the peripheral, the central could in theory send a channel map update with only one channel, but I doubt that a phone (or any serious/certified BLE device) would accept this, and it would probably disconnect immediately.

May I ask why you want to only use one channel?

Best regards,

Edvin