nRF52833 and using Coded PHY and CTE: mutual exclusive?

[Smeedy]

Hi there,

Right now I am doing some dry research into long range Coded PHY for S=8 or S=2 since I need to have some extra room in the link budget to go the distance. The 833 will act as a beacon sending some basic advertising data. I'm also planning to do some direction finding using the 52811 on stationary locations with AoA/ULA since the 533 cannot do IQ-data I read.

But looking at the infocenter radio specs on the 533 (well both actually, the 511 as well) for direction finding, it states that CTE only supports the 1M and 2M data rates.

Is this just an implementation issue? Or is this something deeper within the BT5.1 spec itself? If I look at the Bluetooth Direction Finding specification (page 17), the CTE is appended after CRC and Whitening. But if I look at the Coded PHY page on the Bluetooth 5 Final (page 13) the FEC with the parity info is also appended after the CRC and Whitening. Thus using both at the same time is mutual exclusive?

Thanks for your time,
kind regards,
Martijn

[bjorn-spockeli]

Hi Martijn, 

In the BLUETOOTH CORE SPECIFICATION Version 5.1 | Vol 1, Part A page 281 the following is stated:

DIRECTION FINDING USING BLUETOOTH LOW ENERGY

An LE device can make its direction available for a peer device by transmitting
direction finding enabled packets. Using direction information from several
transmitters and profile-level information giving their locations, an LE radio can
calculate its own position.

This feature is supported over the LE Uncoded PHYs, but not over the LE
Coded PHY.

So yes, Coded PHY and CTE are mutually exclusive. 

BEst regards

Bjørn