Multifrequency Channel Characterization for Curved Tunnels

In this letter, the channel characteristics of tunnels with different curvatures at different frequencies for vehicle-to-vehicle communications are investigated. The relationship between the mean value of path loss, delay spread (DS), frequency, and curvature is analyzed. A high-order polynomial is proposed to describe the path loss exponent (PLE) and a first-order polynomial is used to fit the root-mean-square (RMS) DS. Finally, the neural network is used to build a model to predict the PLE and RMS-DS and to verify the proposed model.