AWR6843AOP: How to configure antGeometry0, antGeometry1, and antPhaseRot if we want to implement beamforming (i.e. use 3 TX to focus on the same direction)

Hey T.C. Chou,

The antenna geometry and phase rotation should still be specified for all antennas, even if they aren't used. You will use the channelCfg to specify which antennas are transmitting and receiving.

antGeometry0 {-1, -1, 0, 0, -3, -3, -2, -2, -1, -1, 0, 0}
antGeometry1 {-1, 0, -1, 0, -3, -2, -3, -2, -3, -2, -3, -2}
antPhaseRot {-1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1}

Regards,

Kristien

Hi Kristien,

Let me move another message into this E2E post below:

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Hey T.C. Chou,

The antenna geometry will be dependent upon the Tx antenna you use, but the antenna phase rotation should always be {-1, 1, -1, 1} due to this being dependent upon Rx phase inversion. As an example, if the Tx antenna used is Tx3, then the antenna geometry would be the following:

antGeometry0 -1 -1 0 0
antGeoemtry1 -3 -2 -3 -2

For any other Tx antennas, refer to the figure above to determine antenna geometry indices for the corresponding virtual antennas.

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Sincerely,

TC.Chou

Hi Kristien,

It's sorry to make some mis-understanding.

When we implement beamforming/beamsteering, we still use 3 TXs (Tx1 + Tx2 + Tx3). However, we modify Phase-Shifter to make 3TX focus on the same direction.

In this case, we think its antenna will be not 3x4(12 virtual antenna), it should be 1x4(4 virtual antenna).

Do you think our opinion is correct or not ?  If it's correct, how to modify antGeometry0 and antGeometry1.

Many thanks again for your help.

Sincerely,

TC.Chou

Hi, Chou:

I checked these CLI commands, they all expect 12 entries.  

And then when I dive deeper, I see the system is support total 4 virtual antenna as below.  

if ((moduleConfig->nRxAnt != 8) && (moduleConfig->nRxAnt != 12))
*errorCode = RADARDEMO_AOACAPONBF_NUMANT_NOTSUPPORTED;

it seems that you will have a problem when using total 4 virtual antennas. 

Best,

Zigang

Dear Zigang,

Many thanks for your information.

We find the code section your provide is located in occupancy_detection_3d_68xx_dss\dss\modules\caponBF2D\src\RADARDEMO_aoaEst2DCaponBF.c 

Does it mean the example of "occupancy_detection_3d" implement CaponBF for AoA Estimation ? 

Sorry for this question. Because we don't find any document to describe CaponBF feature in the example of occupancy_detection_3d.

Sincerely,

TC.Chou

Hi, Chou:

Yes, AWR6843 CPD with classification demo implement capon algorithm for angle spectrum generation and zoom-in angle estimation. 

Best,

Zigang