Fig. 2: Comparison of typical Power Delay Profiles (PDP) before and after back-to-back calibration.

a The raw PDP observed before calibration, where significant fake multipath components (highlighted by red rectangles) appear hundreds of nanoseconds after the peak due to system hardware response. b The calibrated PDP using the back-to-back method, showing the elimination of fake multipaths and a reduction in the noise floor. The red dashed line indicates the multipath extraction threshold (defined as the peak value minus 30 dB). Grey dots represent the original data samples, blue dots denote the filtered valid multipath components, and the vertical magenta dashed line marks the position of the peak power.