Direction finding packet

[Lorens]

Hi,
Considering the new Bluetooth spec. 5.1 and in particular the direction finding feature in the AoA architecture I am wondering if both the devices: the LE transmitter and the LE receiver, must have NRF52811 chip or the transmitter with single antenna can transmit classic BLE advertise (using older chips)?
I mean, will I be able to use my beacon already developed as tag.

Thank you very much

Best regards

[Fred]

There is no requirement for the transmitter. The receiver (that has two or more antennas) will be doing the hard work.

[Simonr]

Hi Lorenzo

It is not possible to use older chips as AoA transmitters, as according to the Bluetooth specifications, you have to send special direction finding signals" that won't be possible to send from chips not supporting Bluetooth 5.1. It is possible to send AoA transmissions in other ways, but this will be out of the Bluetooth spec. and therefore proprietary. So to implement direction finding in nRF products, both transmitter and receiver must be nRF52811.

This blog post is great for learning about how direction finding is implemented in the Bluetooth stack.

Best regards,

Simon

[Fred]

This is technically correct for BLE 5. However, companies (such as Quuppa) have used AoA with standard / older BLE 4 transmitters. So it depends on how far you want to go with your own receiver development.

[Simonr]

Hi Fred

Yes, Quuppa does this, but technically this is proprietary, as they are not implementing AoA according to the Bluetooth specification. So just to clarify, you will have to use nRF52811 transmitters (and receivers) to implement direction finding as the Bluetooth spec. is suggesting.

Best regards,

Simon

[Dave]

Simonr What is the most direct path to get a PCB up and running with nRF52811 5.1-compliant AoA Continuous Tone transmissions?  And how about CT reception and I/Q data reporting for AoA calculation?