Joint automotive radar-communications waveform design

The paper studies the problem of waveform design for a joint Radar-Communications (RadComms) system in an automotive setting characterized by a multitarget environment. The envisaged joint waveform allows exploitation of existing infrastructure to support additional functionalities. In this contribution, an automotive radar employing Phase Modulated Continuous Waveform (PMCW) is considered wherein, the transmission of communications bits is additionally facilitated. Particularly, the RadComms system is enabled by the transmission of Differential Phase Shift Keying (DPSK) communications symbols, each symbol modulated by the PMCW sequence. Further, the receiver processing includes demodulation of the communication symbols in addition to the extraction of the radar parameters — range, Angles of Arrival (AoA) and Doppler returns of the targets. In particular, FFT and subspace-based methods are proposed for estimating the radar parameters which are subsequently used in the demodulation of the communication symbols using diversity combining techniques. The performed study demonstrates the impact of the joint set-up on the two systems. It also highlights the effect of system parameters on the performance of receiver algorithms and the trade-off between the FFT and sub-spaced based processing.