LCMV Beamforming for DDMA MIMO Radar: Nulling with Steering Vector Transformation

The linearly constrained minimum variance (LCMV) beamformer has been widely used in array signal processing for its high resolution and interference suppression capability. However, in Doppler-division multiple access (DDMA) MIMO radar, the coupling between target velocity and angle causes phase pollution in the virtual array, degrading direction-of-arrival (DOA) estimation accuracy. To address this problem, this paper proposes a modified LCMV beamforming method for DDMA radar. The proposed method introduces a Doppler-aware steering matrix transformation to suppress interference from strong targets. Simulation results demonstrate that the method effectively restores weak-target angular responses under single-snapshot conditions and maintains stable sidelobe suppression performance at low signal-to-noise ratios (SNRs).