Waveform Designs for Integrated Sensing and Communication With Low Probability of Intercept Based on the Cyclic Spectrum

In this paper, we investigate a waveform design for integrated sensing and communication (ISAC) systems which simultaneously sense the target and communicate with the user. In this design, we apply the concept of low probability of intercept (LPI) to the waveform design for resisting intercept by the electronic support measure (ESM) system. Different from the conventional LPI waveform design strategies, the cyclic frequency sidelobe level (CFSL) is adopted as the LPI performance metric. We also employ the integrated sidelobe level (ISL) optimization to improve the sensing performance. Consequently, a new LPI ISAC waveform design is proposed with the objective of minimizing the weighted sum of the CFSL and ISL under the constraints of energy budget and peak-to-average-power ratio (PAPR), as well as the similarity constraint to assure the communication quality. Then, to further enhance the sensing capability, a joint design of the transmit waveform and radar receive filter is proposed. As the formulated schemes require solving high-dimensional non-convex problems, efficient algorithms based on the majorization-minimization (MM) and alternating iteration are respectively developed. Finally, the effectiveness of the proposed schemes is verified by simulation experiments.