I. Introduction
The multiple-input multiple-output (MIMO) systems are commonly used in automotive radars for detection, tracking, and classification of targets in traffic environments under diverse weather conditions [1]. The MIMO technology enables achieving high angular resolution while keeping the radar complexity and costs low. To implement the MIMO schemes, it is essential that the waveform of different transmitters can be identified upon signal reception. Therefore, the transmitted waveforms should be orthogonal or have very low cross-correlations.