Stepped-Frequency PMCW-Radar Modulation Scheme for Automotive Applications.

For digital modulation schemes like phase-modulated continuous wave (PMCW) and orthogonal frequency division multiplexing (OFDM), the baseband bandwidth equals the radio frequency bandwidth. High bandwidth is necessary for achieving fine-range resolution. While high sampling rates require expensive analog-to-digital converters (ADCs) at the receiver, low-cost radar solutions are preferred for automotive radar systems. In prior research, a stepped-frequency OFDM modulation scheme was proposed to achieve fine-range resolution while reducing the sampling rates of the ADCs. Motivated by this, we propose a stepped-frequency PMCW modulation scheme to obtain highly separable range-Doppler measurements at reduced sampling rates. For this purpose, the carrier frequency of successively transmitted sequences is varied, resulting in a range-dependent frequency shift along the slow-time domain. The modulation scheme is presented analytically, and its feasibility is investigated in a simulated environment.