Parametrizations of a 77 GHz OFDM Joint Radar Communication

The parametrization of Orthogonal Frequency-Division Multiplexing (OFDM) radar is fundamental when designing a Joint Radar and Communication (JRC) system. The parameters of the OFDM frame simultaneously influence both communication and detection performance. While the radar component requires accurate range and speed estimation, the communication subsystem must transmit a robust signal over the transmission channel. Careful optimization of these parameters in the 77 GHz frequency band enables the design of a communicating radar (RadCom) suitable for automotive applications. In this article, we propose two configurations for OFDM radar and present their effects on both radar and communication performance. The first configuration is designed to provide range and Doppler coverage and resolution as close as possible to those of a typical automotive Frequency-Modulated Continuous Wave (FMCW) corner radar, yielding a subcarrier spacing (SCS) greater than 1 MHz. The second configuration employs a 480 kHz subcarrier spacing, which is compatible with current communication standards, while maintaining acceptable speed and distance resolutions. Simulations show that the second configuration offers advantages in terms of radar detection and communication data rate compared to both the first configuration and FMCW radar. On the other hand, the first configuration delivers better communication performance in terms of Bit Error Rate (BER) under Doppler shift and in noisy environments. Measurement results confirm the good radar performance of OFDM configuration 2 compared with FMCW radar and OFDM in configuration 1 in terms of Signal-to-Noise Ratio (SNR). Therefore, it can be concluded that in configuration 2, the OFDM waveform-based Radcom system is capable of achieving higher radar performance than current automotive radar, while simultaneously enabling fast and reliable V2X communication.