Wave-guide effects in urban viaduct propagation channels for high-speed railway at 930 MHz

The path loss exponent of the urban viaduct propagation channel in high-speed railway (HSR) scenarios is often larger than 2. This is because, particularly in urban environments, buildings and vegetation distributed along the railway tracks at least partially obstruct the signal from the rail side base station. However, given the appropriate distribution of these buildings and vegetation, they can serve as scatterers that partially guide energy via multipath to decrease the path loss, via a wave-guide effect. In this paper, we report on this wave-guide effect for the viaduct channel for HSR in urban scenarios. We collected our measurement data at three example locations in two cities (Xuzhou and Bengbu) along the Beijing-Shanghai HSR in China, and we find that the measured path loss exponents are often less than 2. We also analyze shadow fading in these three areas.