Joint Symbol and ToA Estimation in RIS-Assisted UWB Indoor Localization

The paper introduces a system that combines reconfigurable intelligent surfaces (RIS) with ultra-wideband (UWB) technology for communication and localization. Although UWB has strong potential for location-based services, the low transmitted power of UWB signal currently limits its performance. Reflecting elements at the RIS panel tune the phase of impinged UWB signal towards the receiver (Rx), which enhances its signal power. However, RIS phase optimization is a challenging problem due to wideband nature of UWB signals. The paper analyzes two types of phase settings, perfect and random, for the RIS panel in the RIS-assisted UWB (RUWB) system. Results show that RUWB's bit error rate (BER) and time-of-arrival (ToA) error performance improve significantly as compared to the conventional UWB system without RIS.