Bluetooth 5.1

[Siddharth Venkatesh]

Hi I have a few questions about bluetooth 5.1 and the CTE packets that it transmits. 

1. I know that there is a physical difference in the hardware of a Bluetooth 5.0 chip and a Bluetooth 5.1 chip. I just wanted to know what this difference is exactly. What is added in a Bluetooth           5.1 chip to allow direction finding functionality. 

2. Can the AoD (Angle of Departure) method be implemented? If it cannot be implemented, why not?

3. What do the I/Q samples that are transmitted represent?  

Thanks in advance. You guys have been really helpful. 

[Dmitry]

Hi,

Siddharth Venkatesh said:

1. I know that there is a physical difference in the hardware of a Bluetooth 5.0 chip and a Bluetooth 5.1 chip. I just wanted to know what this difference is exactly. What is added in a Bluetooth           5.1 chip to allow direction finding functionality. 

BT5.1 chip contains direction finding engine  - a module that generates CTE signal, controls antenna switching and writes I/Q samples to memory.  While antenna switching could be implemented with GPIOTE, CTE signal could be generated manually, but without I/Q sampler there's no chance to implement direction finding.

Siddharth Venkatesh said:

2. Can the AoD (Angle of Departure) method be implemented? If it cannot be implemented, why not?

A question is not clear to me...  can it be implemented with BT5.1? - yes. Can it be implemented with BT5.0? - no, there is no hardware support.

Siddharth Venkatesh said:

3. What do the I/Q samples that are transmitted represent? 

You can read good articles here and here about direction finding principles.