ISAC-Fi: Enabling Full-fledged Monostatic Sensing over Wi-Fi Communication

Whereas Wi-Fi communications have been exploited for sensing purpose for over a decade, the bistatic or multistatic nature of Wi-Fi still poses multiple challenges, hampering real-life deployment of integrated sensing and communication (ISAC) within Wi-Fi framework. In this paper, we aim to re-design WiFi so that monostatic sensing (mimicking radar) can be achieved over the multistatic communication infrastructure. Specifically, we propose, design, and implement ISAC-Fi as an ISAC-ready Wi-Fi prototype. We first present a novel self-interference cancellation scheme, in order to extract reflected (radio frequency) signals for sensing purpose in the face of transmissions. We then subtly revise existing Wi-Fi framework so as to seamlessly operate monostatic sensing under Wi-Fi communication standard. Finally, we offer two ISAC-Fi designs: while a USRP-based one emulates a totally re-designed ISAC-Fi device, another plug-andplay design allows for backward compatibility by attaching an extra module to an arbitrary Wi-Fi device. We perform extensive experiments to validate the efficacy of ISAC-Fi and also to demonstrate its superiority over existing Wi-Fi sensing proposals.