Abstract: In order to solve the low communication spectrum efficiency problem of radar-centered integrated sensing and communication (ISAC) waveform, a waveform design method for reconfigurable intelligent surface (RIS)-assisted full-duplex (FD) ISAC is proposed. Firstly, by introducing RIS and FD technology, ISAC signal and communication signal are transmitted respectively in radar pulse repetition interval, and RIS-assisted FD-ISAC system model is constructed. Secondly, combined with radar requirement of low integrated sidelobe level (ISL) and communication requirement of low symbol error rate, an ISAC waveform design optimization model is established, where minimizing ISL as objective function and communication symbol phase similarity, energy and peak-to-average power ratio as constraint criteria, and it is solved by the majorization minimization algorithm. Then, radar and communication performance of RIS-assisted FD-ISAC system are analyzed, and the closed expressions of detection probability and spectrum efficiency are given. Simulation results show that designed ISAC waveform can effectively realize radar detection and information transmission. In addition, compared with traditional FD-ISAC system, the proposed RIS-assisted FD-ISAC system has higher spectrum efficiency and lower symbol error rate.

Key words: integrated sensing and communication, waveform design, full-duplex system, reconfigurable intelligent surface, integrated sidelobe level