Comparison of I/Q- and Magnitude-based UWB Channel Impulse Responses for Device-free Localization

Ultra-wideband (UWB) channel impulse response (CIR) measurements contain information about the presence and location of a person in proximity of sensors. Typically, parts of the CIR, such as the amplitudes of specific multipath components (MPCs) or the magnitudes of the complete CIR are employed for localization. Discarding the phase information of the CIR measurements ignores important information and finally requires longer CIR measurements. Especially in setups where only a small number of sensors are deployed, discarding information degrades the system performance. In this paper, we propose a method that processes the I/Q values of CIR measurements, by aligning, cropping, and rotating the measured CIRs. Localization with I/Q-based CIR measurements is compared with results of magnitude-based approach. In summary, I/Q-based CIR measurements reduce localization errors by approx. 10%. Finally, I/Q-based CIRs provide comparable results with CIRs that are 30% shorter compared to magnitude-based solutions.