RIS-Enabled Self-Localization With FMCW Radar

In the upcoming vehicular networks, reconfigurable intelligent surfaces (RISs) are considered as a key enabler of user self-localization without the intervention of the access points (APs). In this paper, we investigate the feasibility of RIS-enabled self-localization with no APs. We first develop a digital signal processing (DSP) unit for estimating the geometric parameters such as the angle, distance, and velocity and for RIS-enabled selflocalization. Second, we set up an experimental testbed consisting of a Texas Instrument frequency modulated continuous wave (FMCW) radar for the user, and a Sivers transceiver module that emulates RIS-like directional reflections via analog beam steering and signal loopback. While the Sivers module is not a passive RIS, it enables a controlled emulation of RIS behavior suitable for experimental evaluation. Our results confirm the validity of the developed DSP unit and demonstrate the feasibility of RISenabled self-localization using analog RIS emulation.