Measurement-Based Characterization of Train-to-Infrastructure 2.6 GHz Propagation Channel in a Modern Subway Station

Channel characterization is essential when planning wireless communication deployments. We consider the wireless channel characterization in a modern subway station and its corresponding entrance tunnel, a topic greatly overlooked in the literature. We setup a Long-Term Evolution (LTE) Evolved NodeB (eNodeB) transmitter in the middle of the platform of a modern station in the Madrid Metro, Spain, to cyclically transmit frequency-division duplex (FDD) LTE signals at a carrier frequency of 2.6 GHz with a bandwidth of 10 MHz. Two receivers were used to investigate both the eNodeB-train and the eNodeB-mobile links. The train was moving at a constant speed of 18 km/h from the entrance tunnel until it is completely stopped at the end of the station. Using the multipath components extracted with the space-alternating generalized expectation-maximization (SAGE) algorithm, we characterized the wireless channel response for both links based on the following parameters: power delay profile, root mean square delay spread, Doppler power spectral density, small-scale fading distribution, and K-factor.