Spatial-Domain Mutual Interference Mitigation for MIMO-FMCW Automotive Radar

This paper considers mutual interference mitigation among automotive radars using frequency-modulated continuous wave (FMCW) signal and multiple-input multiple-output (MIMO) virtual arrays. For the first time, we derive a spatial-domain interference signal model that accounts for not only the time-frequency incoherence (e.g., different FMCW parameters and time offsets) but also the slow-time MIMO code incoherence and array configuration differences between the victim and interfering radars. Using the explicit interference signal model with the standard MIMO-FMCW object signal model, we turn the interference mitigation into a spatial-domain object detection under incoherent MIMO-FMCW interference. By exploiting the structural property of the derived interference model at both transmit and receive steering vector space, we derive a detector via beamforming optimization to achieve good detection performance and further propose an adaptive version of this detector to enhance its practical applicability. Performance evaluation using analytical closed-form expressions, synthetic-level simulation and system-level simulation confirms the effectiveness of our proposed detectors over selected baseline methods.