Random phase code for automotive MIMO radars using combined frequency shift keying‐linear FMCW waveform

Automotive radar is a key component for self-driving cars and advanced driver assistant systems. The major requirements of recent automotive radars are high angular resolution and multiple target detection with the constraints of small size, low power, and low cost. With appropriate transmitter spacing, co-located multiple-input–multiple-output (MIMO) radar can emulate larger aperture arrays, producing the required high angular resolution. However, MIMO radar requires waveforms that are orthogonal in frequency, time, or code domain, and orthogonal waveforms developed for pulse radars are unsuitable for automotive frequency modulated continuous waveform (FMCW) radars. This study proposes a code division multiplexing method for automotive MIMO radars by selecting the combined frequency shift key-linear FMCW waveform. The authors show the performance through simulation and discuss constraints. The proposed method is suitable for automotive radars because not only can high angular resolution be achieved by a small number of arrays, but also multiple targets can be detected with the low sampling rate and computational power.