OFDRA: Optimal Femtocell Deployment for Accurate Indoor Positioning of RIS-Mounted AVs
Alireza Famili, Tolga Atalay, Angelos Stavrou, Haining Wang, Jung‐Min Park
Abstract
The pursuit of high-accuracy localization without relying on the global positioning system (GPS) has gained significant interest in recent years. The deployment of autonomous vehicles (AVs) in diverse indoor applications exemplifies a prominent domain where the demand for a robust positioning system is evident. With the advancements in 5G and beyond radio access networks (RAN), the availability of new positioning signals presents an opportunity to deliver accurate location estimates for these applications. Nevertheless, these signals encounter substantial path losses in indoor environments. Additionally, the precise localization within existing frameworks requires stringent synchronization, which is challenging to meet. In this paper, we propose OFDRA: Optimal Femtocell Deployment for Accurate Indoor Positioning of RIS-Mounted AVs, a novel positioning framework that is robust against multipath and does not require strict synchronization between anchor-anchor or anchor-target entities. Specifically, OFDRA is designed to operate in scenarios where the line of sight (LOS) exists. The first design objective of OFDRA is the mitigation of ranging errors by leveraging a compact reconfigurable intelligent surface (RIS) mounted on top of AVs acting as a programmable mirror in a 5G network. The second design objective is to achieve optimal anchor placement in three-dimensional indoor spaces, thereby reducing the geometric dilution of precision (GDOP) and mitigating geometric-induced errors in the final position estimation. Our experimental verification reveals that the localization error is influenced by GDOP, encompassing both the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$X-Y$ </tex-math></inline-formula> plane and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Z$ </tex-math></inline-formula> -axis estimations. Through optimized anchor placement, OFDRA demonstrates a seven-fold enhancement in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Z$ </tex-math></inline-formula> -axis accuracy compared to the state-of-the-art, achieving a sub-1 m three-dimensional accuracy for more than 95% of cases.