MIMO Signal Design for Coexistence with LFM

Most of existing waveform optimization works for colocated Multiple-Input Multiple-Output (MIMO) radar focuses on polyphased-coded waveforms, which are discrete and suitable for optimization. In this paper, we optimize MIMO radar waveform design for a radar system that can also simultaneously illuminate continuous Linear Frequency Modulated (LFM) waveforms, such that in the receive end, they have good auto correlation sidelobes, and good cross correlation sidelobes to separate returns caused by different transmit signals. We first samples an LFM signal under a sampling frequency and then formulates a waveform optimization criterion that simultaneously suppress auto correlation sidelobes of MIMO waveforms and cross correlation sidelobes with the sampled discrete LFM signal. Numerical results with a phase coded signal indicate that this method can reach a cross correlation level lower than that between an LFM signal with opposite frequency modulation ratios. Moreover, more phase coded signals are also given to test the method and to investigate the impact of the LFM sampling interval on the final sidelobe level.