New wireless tech locates users through walls without extra equipment
Researchers have developed a method to pinpoint a user's location and map communication channels simultaneously using smart reflective surfaces, even when direct signal paths are blocked. The technique cuts the data overhead needed for positioning by orders of magnitude, potentially enabling faster, more efficient next-generation wireless networks in urban environments and indoor spaces where traditional methods fail.
Originaltitel: Joint Pilot-Based Localization and Channel Estimation in RIS-Aided Communication Systems
<p>In this letter, we investigate the use of reconfigurable intelligent surfaces (RISs) to jointly estimate the position and channel of a user equipment (UE) using uplink pilot signals. We consider a setup with a user and a base station (BS), where the direct path between the BS and the UE is blocked and virtual line-of-sight (LOS) links are created over two reconfigurable intelligent surfaces (RISs). We investigate the benefits of exploiting the channel geometry to estimate the user’s position and the user-RIS channels jointly in terms of estimation performance and pilot overhead. To this end, we consider the Cramér-Rao Lower Bound for channel estimation and UE localization. Our numerical results show that exploiting the LOS structure of the channels improves the channel estimation performance by several orders of magnitude and reduces the channel estimation performance by reducing the number of unknown parameters.</p>