Photonic-Based Flexible Integrated Sensing and Communication With Multiple Targets Detection Capability for W-Band Fiber-Wireless Network

In the impending 6G era, the integration of sensing and communication (ISAC) systems in the millimeter-wave (MMW) band will assume a pivotal role across a myriad of applications, thus enhancing everyday convenience. The photonic-based MMW ISAC system, renowned for mitigating electromagnetic interference and integrating with the fiber-wireless network, exhibits tremendous potential across diverse application domains. In intricate application contexts, the ISAC system should possess the capability to execute multitarget detection to preclude false target generation, simultaneously maintaining a balance between radar sensing and communication performance. This article presents a flexible photonic-based
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-band ISAC system, designed to facilitate centralized, seamless fiber-wireless networks. It boasts the ability to detect multiple targets within the same angular sector. We scrutinize the potential causes for false target generation and the corresponding solutions in detail, validating the correctness of this theory through simulations and experiments. In addition, we incorporate subcarrier modulation (SCM) and linear frequency modulation (LFM) signals using frequency-division multiplexing (FDM). This allows us to allocate the bandwidth and power of these two signals, thus achieving a balance between sensing and communication. To demonstrate this concept, we designed a photonic-based ISAC system for the fiber-wireless network operating at 97.5 GHz over 10-km fiber transmission, which yielded access rates ranging from 15 to 60 Gbit/s after 1-m free-space transmission and range resolutions varying from 1.76 to 3.15 cm. The distance error subsequent to external calibration is under 3 cm.