See-Through Walls With Wi-Fi: Joint Utilization of RSSI and CSI for Enhancing Building Layout Reconstruction

In building layout reconstruction (BLR), electromagnetic (EM) wave propagation in indoor environments involves not only direct paths (DPs) but also multiple non-DPs due to reflections, diffractions, and scattering. Traditionally, received signal strength indicator (RSSI)-based methods have been employed for BLR. However, RSSI is highly susceptible to multipath interference, leading to degraded reconstruction accuracy. To address this limitation, this article leverages the fine-grained characterization capabilities of channel state information (CSI) to mitigate the weaknesses of RSSI in multipath environments. Specifically, we propose a novel method that integrates CSI phase fluctuations with RSSI measurements to achieve high-quality BLR for various building structures. This approach enables the independent reconstruction of different building features, which are subsequently fused to enhance the overall BLR image. Experimental results demonstrate that, compared to conventional RSSI-based BLR methods, the proposed approach significantly reduces multipath interference, resulting in improved reconstruction accuracy.