Channel Measurement, Characterization, and Utilization of the ETC Systems in All-Metal Immersed Tunnel Scenario

The channel characteristics of immersed tunnels play a crucial role in the design and optimization of electronic toll collection (ETC) communication systems in such environments. Due to the lack of channel characteristics for all-metal immersed tunnel environments, this paper conducts an in-depth study on channel measurement, channel modeling, and optimization of ETC systems within all-metal immersed tunnels. Using a channel measurement system based on the universal software radio peripheral (USRP), this study extracts multidimensional channel characteristic parameters from the measured data, such as path loss (PL), shadow fading (SF), K-factor (KF), root mean square delay spread (RMS DS), power angular spectrum (PAS), and azimuth angle spread (ASA). The unique characteristics of the all-metal tunnel are analyzed in comparison to tunnels made of other materials. To develop a comprehensive all-metal immersed tunnel channel model meeting the quasi-deterministic radio channel generator (QuaDRiGa) requirements, we employed ray tracing (RT) methods to supplement angle domain parameters. Subsequently, we used this channel model to aid in the design and optimization of ETC systems, addressing transaction failures and erroneous transactions within all-metal immersed tunnels by establishing optimization targets and constraints, resulting in optimal height, tilt angle, transmission power, and beamforming. The findings of this research not only enrich the channel scenarios in QuaDRiGa but also provide practical guidance for improving the performance of ETC systems.