Co-wavelength integration of distributed acoustic sensing and communication with peak-to-average power ratio mitigation.

Co-wavelength integrated sensing and communication (ISAC) systems with a shared transmitter suffer from severe power competition between high-energy sensing pulses and communication signals. Direct waveform superposition results in an extremely high peak-to-average power ratio (PAPR), while conventional peak-clipping methods inevitably bring a distortion of sensing waveforms. To address such an issue, we propose a valley-filling waveform shaping (VFWS) scheme. Instead of suppressing sensing pulses-induced peaks, VFWS enhances the communication waveform during the temporal intervals without sensing pulses, thereby reducing the PAPR without modifying the sensing pulses. Experimental results verify that the proposed VFWS scheme significantly improves the dynamic-range utilization at the shared transmitter and effectively enhances the communication performance under the quantization-limited condition. Compared with the conventional scheme, the VFWS scheme achieves a 2.1 dB OSNR gain and reduces the required communication-to-sensing power ratio (CSPR) by 4 dB at the 7% hard-decision forward error correction (HD-FEC) threshold. Meanwhile, the sensing performance remains almost the same. Those results indicate that VFWS does provide a hardware-efficient solution for the co-wavelength ISAC systems.