Experimental study of propagation characteristics for wireless communications in high-speed train cars

This paper describes the measurement results of propagation loss characteristics in high-speed train cars. We focus on the propagation loss in intra-car communications using a 2-GHz band and inter-car communications using a 5-GHz band. The measurement campaign is carried out using real train cars under both running and non-running conditions. The measurement results for intra-car communications indicate a waveguide effect in a closed space environment, and based on the results, we clarify the maximum propagation loss expected in intra-car communications. The measurement results for intercar communications indicate that the propagation loss is greatly affected by waves re-entering the car through train windows, and we evaluate the influence of the re-entering waves on the variance in the propagation loss between the train cars.