Joint Transmit Waveform Design for Integrated Sensing and Communication Systems Using Symbol-Level Precoding

This letter investigates the transmit waveform design for an integrated sensing and communication (ISAC) system with multi-input multi-output (MIMO) architectures, which includes independent sensing and communication waveforms. Unlike existing studies that typically treat the sensing waveform as interference to communication, we utilize symbol-level precoding strategies to design sensing waveform that enhances communication and sensing performance simultaneously. The transmit waveform design is formulated as an optimization problem, where the objective function quantifies the difference between the total transmit waveform and the desired radar-only waveform, subject to constraints on the signal-to-interference-plus-noise ratio (SINR) of communication waveform, the transmit power budget, and the symbol-level precoding strategies of sensing waveform. We then solve this optimization problem through second-order cone programming (SOCP). To complete the design, we develop a design scheme for generating the constant-modulus radar-only waveform using the constrained least squares (CLS) algorithm. Finally, numerical results validate the effectiveness of the algorithm.