A Novel Design of Low-PAPR OFDM-DCSK Waveform With Riemann Matrix-Based G-SLM for ISAC

Abstract

This letter introduces an orthogonal frequency division multiplexing differential chaos shift keying (OFDM-DCSK) waveform for communication-centric integrated sensing and communication (ISAC), which simultaneously enables reliable noncoherent communication and robust sensing capabilities. To further address the high peak-to-average power ratio (PAPR) issue of OFDM-based waveforms, a Riemann matrix–based group selected mapping (G-SLM) scheme is incorporated to reduce PAPR under ISAC sensing constraints. The proposed G-SLM achieves significant PAPR improvement compared with conventional SLM methods while requiring no side information at the receiver. Closed-form expressions are derived for the ambiguity function and bit error rate (BER) in the proposed systems with and without G-SLM. Both analytical and simulation results verify that the OFDM-DCSK waveform integrated with G-SLM maintains communication reliability and sensing accuracy compared to the conventional OFDM-DCSK waveform, while reducing the PAPR with only slight main lobes broadening and modest side lobes elevation. These features make the proposed scheme particularly suitable for ISAC applications in complex wireless environments under low and moderate mobility conditions.