Suppression of signal distortion within CSI ratio based wireless sensing by orthogonal antennas

The utilization of the Channel State Information (CSI) ratio offers a promising avenue to extend the range and precision of wireless sensing applications. Recent research employing the CSI ratio has made steady progress, yet encountered unanticipated signal distortions, a phenomenon that lacks comprehensive exploration and elucidation. In this study, we first delve into the roots of this distortion by modifying the traditional CSI ratio model and establishing its connection with a pertinent parameter termed the Static to Dynamic Signal Amplitude (SDSA) ratio. We then demonstrate that the SDSA ratio wields substantial influence over the distortion encountered within diverse environmental scenarios. Finally, we introduce a novel approach involving the deployment of antennas with orthogonal orientations to counteract and suppress this form of signal distortion. Our experimental results successfully validate the rightness of our theoretical derivation as well as the efficacy of the proposed method in effectively mitigating pronounced distortions. Our proposed approach for the suppression of the signal distortion within CSI ratio based wireless sensing can pave the way to a variety of delicate applications requiring higher sensing accuracy.