Symbol-Level Precoding-Based Waveform Design for Low-PAPR Multi-User MIMO-OFDM Integrated Sensing and Communication Systems

The multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM)-based integrated sensing and communication (ISAC) system has been intensively investigated in the past years, as it is a promising candidate for realizing ISAC in next-generation wireless systems. However, even though it is clear that OFDM-based systems could suffer from high peak-to-average power ratio (PAPR), the design of low-PAPR multi-user MIMI-OFDM ISAC systems has not been well-explored. To fill this gap, this paper investigates the low-PAPR multi-user MIMI-OFDM ISAC system design. Specifically, by using radar ambiguity function and symbol-level precoding concept, this paper first formulates a low-PAPR multi-user MIMI-OFDM ISAC system design problem that optimizes the sensing performance subject to communication performance and PAPR constraints. To solve the problem, the communication performance and PAPR constraints are first transformed to convex constraints, and then the successive convex approximation is used to derive an iterative solution approach. Simulation results show that our proposed design approach can provide the effective low-PAPR ISAC design that outperforms the reference scheme.