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AWR2944: Seeking Solutions for DDMA Speed Overlap and Phase Shifter Configuration on TI AWR2944

?? ?
Prodigy 100 points
Part Number: AWR2944

Tool/software:

Hey everyone,
As we know, the TI AWR2944 uses DDMA technology to divide the Doppler spectrum into multiple subbands for signal separation. However, when multiple targets are located within the same range cell and their speed differences are integer multiples of the Doppler subband spacing, these targets will overlap in the Doppler domain. For example, if two targets have a speed difference that is exactly equal to the Doppler subband spacing, their echo signals will overlap in the Doppler spectrum, making it impossible for the radar to distinguish between the two targets.
Currently, in 2944, chirp can be configured up to 512 types at most. If we use two different DDMA modulation parameters, we need to limit each set of modulation parameters to 256, or reconfigure the phase shifter before each frame transmission. However, our tests have found that reconfiguring the phase shifter for 384 chirps before each transmission takes about 7ms. So, I have several questions:
  1. Are there any other solutions to address the issue of DDMA speed indistinguishability?
  2. Can chirp now be configured with more than 512 types?
  3. Is there a fast configuration method that can reconfigure the phase shifter in a shorter time?
Any insights or suggestions would be highly appreciated!
Best regards,
Patrick
  • +1
    TI__Mastermind 20810 points

    Hi Patrick,

    ?? ? said:
    Are there any other solutions to address the issue of DDMA speed indistinguishability?

    Currently we do not handle such cases in the application. We expect the velocity of the vehicle to change in the next frame and the detection should be possible in the next frame.

    ?? ? said:
    Can chirp now be configured with more than 512 types?

    In AWR2944, you can configure a maximum of 512 unique chirps. But you have another parameter - chirp loops to repeat the given set of chirps in each frame. With legacy chirp configuration, upto 255 chip loops can be configured.

    Refer to "C:\ti\mmwave_mcuplus_sdk_04_07_00_01\mmwave_dfp_02_04_17_00\docs\mmWave-Radar-Interface-Control.pdf"

    ?? ? said:
    Is there a fast configuration method that can reconfigure the phase shifter in a shorter time?

    If you are looking at reconfiguration of the phase shifter while the frames are on-going, refer to 

    (+) AWR2944: dynamic chirp and phase shift reconfiguration - Sensors forum - Sensors - TI E2E support forums

    Regards,

    Samhitha