Postprocessing Time-Alignment Method of Power Angular Delay Profile for Automated mmWave WPAN Channel Sounding

Abstract

Accurate propagation channel measurements and modeling—encompassing both angular and delay characteristics—are fundamental to the design of millimeter wave (mmWave) communication systems. Accordingly, steerable directional antennas and strict time-synchronization are commonly employed to capture power angle delay profiles (PADPs) that share synchronized standard time axes. However, time synchronization requires labor-intensive management to ensure clock synchronization during or after measurements, which hinders the construction of massive propagation channel databases. Thus, this study aimed to develop a streamlined channel sounding system by fully automating the PADP acquisition flow. First, an automated data-driven postprocessing method is proposed to reconstruct a time-synchronized PADP from an unsynchronized PADP, thereby discarding the requirement for managing clock synchronization. This approach is well-suited for simple channel sounding setups in mmWave wireless personal area network (WPAN) scenarios. The proposed method was evaluated through raytracing simulations tailored to WPAN systems with a comprehensive analysis of the impact of various measurement parameters. Simulation results demonstrated that the method achieved a time-alignment error of less than 1 ns in over 99% of cases across various receiver (Rx) locations and Rx antenna rotation angles in noise-free environments. Moreover, a real-world experimental evaluation revealed that the time-aligned PADP obtained using the proposed method reached an alignment root-mean-square error (RMSE) below 1 ns. These findings strongly demonstrate the feasibility of the proposed method for channel sounding in mmWave WPAN systems.