RIS-Enhanced Backscatter Communication for Vehicular Self-Localization

In this letter, we propose a novel vehicular self-localization technique leveraging reconfigurable intelligent surface (RIS)-enhanced backscatter communication. Specifically, while transmitting frequency modulated continuous wave (FMCW) signals for collision avoidance, the vehicle simultaneously estimates its distance from multiple roadside units (RSUs) and demodulates RSUs’ location information backscattered from the RISs. To enable accurate parameter estimation and data demodulation, we propose an element-wise complex division algorithm that effectively decouples the sensing parameters and data symbols. We also demonstrate that the estimated sensing information can assist in symbol demodulation, thereby significantly reducing pilot overhead. Simulation results validate that the proposed algorithm significantly improves the localization accuracy and achieves comparable demodulation error performance to that of perfect channel state information with only 1% demodulation reference signal.