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Original question:

IWR6843ISK: modified antenna design

IWR6843ISK: order of doppler chirps to be supplied to doppler computation

Takatoshi Tsuji
Expert 1550 points
Part Number: IWR6843ISK

Hello support team,

According to below doppler DPU, data processing is started with Tx0-Rx1 and Tx1-Rx1 as 1st iretation and Tx0-Rx2 and Tx1-Rx2 is supplied as 2nd iretation. 

C:\ti\mmwave_sdk_03_03_00_03\packages\ti\datapath\dpc\dpu\dopplerproc\docs\doxygen\html\index.html

I suppose it is not necessary to mofiy the order of doppler chirps to be supplied to the data processing, regardless of antenna array.

Am I right ? I appreciate any of your advice.

(Actually I am concerned about our original antenna design, as discussed https://e2e.ti.com/support/sensors/f/1023/p/916460/3409875#3409875 .)

Best regards,

Taka

 

  • 0
    TI__Mastermind 30405 points

    Hi Taka-san,

    The order of received symbols depends upon the transmit order and the ordering is important for the angle of arrival functionality to work correctly. If you are not changing the TX order (i.e. the chirp to TX antenna association in the chirpCfg commands), the Doppler chirp order will not change i.e. you do not need to modify the order.

    Regards

    -Nitin

  • 0 in reply to Nitin Sakhuja
    Expert 1550 points

    4428.MIMO_config.xlsx

    Hello Nitin,

    > The order of received symbols depends upon the transmit order and the ordering is important for the angle of arrival functionality to work correctly.

    Yes. I have modifed data order before RX phase compensation block in AOA DPU, depending on virtual antenna array in our original design.

    > . If you are not changing the TX order (i.e. the chirp to TX antenna association in the chirpCfg commands), the Doppler chirp order will not change i.e. you do not need to modify the order

    I appreciate if you can advise correct doppler chirp order (=ping/pong pattern) for attached antenna array.

    Best regards,

    Taka

  • 0 in reply to Takatoshi Tsuji
    TI__Mastermind 30405 points

    Hello Taka-san,

    It is not clear why you need to modify the order of symbols before the RX phase compensation in AoA DPU? Could you please clarify?

    Regards

    -Nitin

  • 0 in reply to Takatoshi Tsuji
    TI__Expert 5235 points

    For the purpose of estimating doppler and generating the detection matrix, the order of Tx-Rx pairs in the processing does not matter, each pair will produce the same doppler estimates but we do all pairs to accumulate the energies (sum of log abs) of all pairs to improve the SNR for detection. We are doing what is non-coherent combining here.

  • 0 in reply to Piyush_
    Expert 1550 points

    Hello Piyush, Nitin,

    Thank you for your reply. I understand the order of Tx-Rx pairs basically does not matter but it may be better to choose non-coherent pairs.

    Best regadrs,

    Taka