A Hybrid Slow-Time Coding Framework for Automotive MIMO Radar

The implementation of MIMO radar in automotive applications requires careful waveform design in order to permit the separation of the transmit channels at the receiver. While there are a number of approaches for achieving this, slow-time coding is preferred in automotive applications as it allows the use of scaled versions of a single LFM waveform waveform across all antennas and pulses. In this paper, we present hybrid slow-time scheme that delivers the MIMO functionality in automotive radar systems by partitioning the transmit array into groups of transmit elements. Code division multiplexing is then applied across the groups whereas DDMA is used within each group. Spatial processing is then employed to generate a two dimensional angle-Doppler spectrum, leaving the target detection to the end. This approach requires only a small number of orthogonal codes to be designed, which alleviates the code design challenge, and enhances performance while keeping the probability of target collisions to a minimum. Simulations demonstrate the ability of the proposed method to resolve the target ambiguities.