BOOSTXL-AOA: wrong phase different between different antennas, derived from the raw IQ data

Hi Jet,

Good to have you back! It looks like your project is moving forward, that's nice.

The phase difference between two antennas depends on the path difference. As I have shown below, there are ways to obtain almost no path difference between antennas A1.2 and A1.3 while having path difference with A1.1.

When it comes to antenna switching, this is required by the Bluetooth Core specifications. You could modify the python script in order to force the CC2642R's radio to provide the over-sampled IQ data. That way you could have up to 4 consecutive samples per antenna. The following configuration should allow this (EDIT: It looks like you already have 4 samples per sampling slot - this code may be useful for others so I keep it here):

                    "aoa_run_mode": "AOA_MODE_RAW",  ## AOA_MODE_ANGLE, AOA_MODE_PAIR_ANGLES, AOA_MODE_RAW
                    "aoa_cc26x2": {
                        "aoa_slot_durations": 2,
                        "aoa_sample_rate": 1,
                        "aoa_sample_size": 1,
                        "aoa_sampling_control": int('0x11', 16),
                        ## bit 0   - 0x00 - default filtering, 0x01 - RAW_RF no filtering,
                        ## bit 4,5 - default: 0x10 - ONLY_ANT_1, optional: 0x20 - ONLY_ANT_2
                        "aoa_sampling_enable": 1,
                        "aoa_pattern_len": 3,
                        "aoa_ant_pattern": [0, 1, 2]
                    }

When it comes to estimation algorithms, MUSIC/ESPRIT can definitely work the one-by-one collect data. Actually, the total CTE length is 160 us and one sample is collected every 2 or 4 us. So for most of the use-cases, I think it is fair to consider that the samples are collected simultaneously.

I hope this will help,

Best regards, 

Hi Clement,

I later replace BPSK to single-tone in my attached code, and it works.

I also check the phase different it match your description, thanks.

Best

Jet