SWRA662A January   2020  – September 2022 AWR1243 , AWR1443 , AWR1642 , AWR1843 , AWR1843AOP , AWR2243 , AWR6843 , AWR6843AOP , IWR1443 , IWR1642 , IWR1843 , IWR6443 , IWR6843 , IWR6843AOP

 

  1.   Interference Mitigation For AWR/IWR Devices
  2.   Trademarks
  3. 1Introduction
  4. 2Types of Interference in FMCW Radar
    1. 2.1 FMCW Radar
    2. 2.2 The Radar Equation for Interference
    3. 2.3 Types of Interference
      1. 2.3.1 Crossing Interference
      2. 2.3.2 Performance Analysis for Crossing Interference
      3. 2.3.3 Parallel Interference
      4. 2.3.4 Between Crossing and Parallel Interference
  5. 3Interference Avoidance
    1. 3.1 Standardization: Different Frequency Band and Time Slot for Different Radars
    2. 3.2 Different Starting Time for Parallel Interference
    3. 3.3 Sensing and Avoidance
    4. 3.4 Antenna Polarization
  6. 4Localization and Interference Mitigation
    1. 4.1 Localization
    2. 4.2 Mitigation
  7. 5Dithering and Randomization
  8. 6Conclusion
  9. 7References
  10. 8Revision History

The Radar Equation for Interference

First, let us define two terms: a victim and an aggressor. A victim is a radar device whose receiver is affected by interferers. An aggressor is a radar device whose transmit affects the victim's receiver.

The received signal strength in dBm (PInterference) of an interfering radar can be computed using Equation 1.

Equation 1. GUID-EF87EEB4-F996-43C5-8BA4-BBBB22734B67-low.gif

where

  • Ptx is the aggressor radar’s transmit power (in dBm)
  • txAntGain is the aggressor radar’s transmit antenna gain (in dB)
  • rxAntGain is the victim radar’s receive antenna gain (in dB).

The distance between the aggressor and the victim is R, and the average RF wavelength is λ.

The radar equation for targets is shown in Equation 2.

Equation 2. GUID-58F1D1D0-3915-4B79-A3E7-281BFB67A6EE-low.gif

Comparing the two equations shows that the path loss effect (that is, the effect of R) is weaker for interferers than targets. In other words, interference is likely to dominate the received signal even if it is far away.