Photonic-Based W-Band Integrated Sensing and Communication System With Flexible Time- Frequency Division Multiplexed Waveforms for Fiber-Wireless Network

In the upcoming 6G, the integrated sensing and communication (ISAC) system in the millimeter wave (MMW) band will have a vital role in numerous application scenarios, enhancing the convenience of our lives. The photonic-based MMW ISAC system can exploit the broad bandwidth of photonic devices, significantly improving system performance. Furthermore, the use of photonic devices enables the seamless integration of the ISAC system with the fiber-wireless network. In this paper, we proposed a simple-structured photonic-based W-band ISAC system, incorporating optical fiber transmission into the system. Additionally, we designed integrated waveforms for time-frequency-division multiplexing (TFDM), allowing for flexible tradeoffs between data rate, range resolution, and detection distance according to the requirements of application scenarios. As a proof-of-concept, a photonic-based ISAC system for the fiber-wireless network with flexible TFDM waveforms at 96.5 GHz over 10-km fiber transmission was demonstrated, achieving adaptive access rates from 15 to 60 Gbit/s after transmission over 1-m free space, and adaptive range resolutions from 1.53 to 4.39 cm. Moreover, this paper provides a detailed analysis of the causes of system distance error and corresponding solutions. In the experiment, the distance error of the proposed system can be reduced to less than 3 cm after external calibration.