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Original question:

AWR1843: Is there a possibility of BPM transmission for 3Txs

AWR1843: Beam steering for x degrees in mmwave studio

Isura Nirmal
Prodigy 80 points
Part Number: AWR1843

Hi ,

I have browsed the forum to look for a minimal example which uses an x degrees beamwidth for one single frame using all the 3 antennas. I think this is frame-based beam steering

It turned out that there are several examples for the BPM mode but not for the phase shifter settings. My confusion is there are many places to change but there is no way for me to verify I'm doing this correctly. Appreciate it any explanations for this.

1 st attempt.  Phase Shifter in sensor Config.

I have followed the following formula the below document to generate the phase shift values for +20 degrees and put them into the Phase Shifter in sensor Config. 

dev.ti.com/.../node

2nd attempt.  BPM config tab

Here I have tried the same formula but divided it by 5.625. I wanted all the chirps in the frame to have this configuration. 

Q1: First thing is I don't see much SNR gain for the objects in 20 degrees compared with TDM-MIMO. Am I doing something wrong?

Q2: Is there a way to get the beam width, I assume 20 degrees is the boresight angle. 

Q3: What changes need to be done for the signal processing pipeline when it comes to AoA estimation to calculate azimuth and elevation angle?

Q4: What will be the angle resolution in this mode? 

Thank You!

Isura

  • 0
    TI__Guru*** 148954 points

    Hi,

    Please find attached an example on how to compute the phase shifter values and how to capture the raw data with mmwave studio.

    Please note the script was used with AWR1843AOP board. For the AWR1843BOOST board the order of Tx numbers is reversed.

    Thank you

    Cesar

    AWR1843AOP_Phase_Shifter_Script.zip

  • 0 in reply to Cesar
    Prodigy 80 points

    Hi Cesar, thanks a lot for the answer and scripts. I will use the instructions for the mmwave studio. Appreciate it if you could answer the Q2-Q4

  • 0 in reply to Isura Nirmal
    TI__Guru*** 148954 points

    Hi

    Please give me a few days to get back to you

    thank you

    Cesar

  • 0 in reply to Cesar
    Prodigy 80 points

    Hi Cesar, Just following up whether there is any update regarding this. 

    Thank You! 

  • 0 in reply to Isura Nirmal
    TI__Guru*** 148954 points

    Hi,

    Here are some answers

    Please see some helpful threads

    https://e2e.ti.com/support/sensors-group/sensors/f/sensors-forum/862661/iwr6843isk-beam-forming-3d-vs-tx-power-of-each-antenna

    https://e2e.ti.com/support/sensors-group/sensors/f/sensors-forum/964171/awr2243-question-of-the-rx-azimuth-angle-resolution-in-txbf-mode

    Q2: We don't have beam width information available

    Q3: If the phase is changed for all the chirps in the frame there is no change to the processing chain. If the chirps within a frame have different phases than you would have to modify the processing chain accordingly.

    Q4: see threads above

    thank you

    Cesar

  • 0 in reply to Cesar
    Prodigy 80 points

    Hi Cesar,

    Thanks a lot for the information. Ihave few other questions.

    1) About the antenna indexing. I do understand that we add the pahse shift to the the transmitter closests to the receiver. In this case Tx3 . 

    I have a setup where two objects are present. Range and angle information of the objects are correct in both experiment


    As you have mentioned, I have reversed the phase shift values for AWR1843 so that the phase shifter line became like this.
    ar1.SetPerChirpPhaseShifterConfig(0, 0, 45,23, 0)

    The detection results looks like this. 

    However, for the original code you have provided(for AWRAOP), detection results are as follows.

    ar1.SetPerChirpPhaseShifterConfig(0, 0, 0,23, 45)

    You can see the SNR has a clear improvement. I don't know any other way to interpret this result but seems to me either I'm doing something wrong from my side or there seems to be an issue with the configuration file. 

    2) LDO Bypass operation, I can see the script does it, do I have to do anything to the bord to enable this.

    3) FOr MIMO radar processing angle estimation, if we enable 3 Tx and 4 Rx, w ehave virtual antenna array of 12. So we can select 8 for the azimuth plane and 4 for the elevation.

    For Beam steering, we have only 4 Rx since the 3 Tx transmit simulteneously. My confusion is how to select antennas for angle estimation. 

    We can take 4 rx as azimuth processing, what about the elevation processing, we require to have at least two antennas to do that. 

    Appreciate it any help related to this.

  • 0 in reply to Isura Nirmal
    TI__Guru*** 148954 points

    Hi

    Q1 - 0 phase shift is applied to Tx1. In mmWave Studio API you should still use ar1.SetPerChirpPhaseShifterConfig(0, 0, 0,23, 45)

    Q2 - There is nothing else to do

    Q3 - with beam steering there is no elevation information

    thank you

    Cesar

  • 0 in reply to Cesar
    Prodigy 80 points

    Hi Cesar, Thanks a lot for the reply.

    Q1 I seem to have taken your advice wrongly when you mention to me to reverse the order of the Tx between AOP and BOOST Boards.
    Q 2. Thanks for confirming this
    Q 3. I didn't see the advanced frame configuration in the MRR beam steering lab where a subframe has MIMO mode so it can get x-z plane information. Is there any way to get the configuration information in that lab? Seems to me that it's hardcoded. 

  • 0 in reply to Isura Nirmal
    TI__Guru*** 148954 points

    Hi,

    The MRR beam steering lab does not support MIMO mode.

    You can get the MIMO configuration from the MRR lab. It is provided in

    mmwave_automotive_toolbox_3_3_0\labs\lab0007_medium_range_radar\src\common\mrr_config_chirp_design_USRR30.h

    Thank you

    Cesar