OTFS-Chirp-Based Dual-Functional Waveform Design for Sensing and Communication

The integrated sensing and communication (ISAC), which enables the same waveform to perform communication and sensing tasks, has increasingly garnered widespread attention in academic and industrial circles. The sidelobe level of the ambiguity function (AF) is a crucial metric for evaluating sensing performance. In this paper, we propose a novel waveform design that integrates Orthogonal Time Frequency Space (OTFS) modulated signal and chirp signal, termed OTFS-chirp. Our design aim is to reduce the sidelobes of the AF of OTFS by introducing the chirp signal while the designed waveform still has excellent communication performance. Furthermore, the bit error rate (BER) and the AF of the designed OTFS-chirp waveform are derived approximated closed-forms. Experimental results indicate that the proposed OTFS-chirp waveform has better sensing performance compared with OTFS and OFDM; Meanwhile, the communication performance of OTFS-chirp is similar to that of OTFS, which is better than that of OFDM.