Fading Analysis for the High Speed Railway Viaduct and Terrain Cutting Scenarios

A good understanding of the fading characteristics in high speed railway environment is essential for the design of a high reliable railway wireless network. In this paper, measurements have been taken in both high speed viaduct and terrain cutting scenarios using track side base stations (BSs) of the railway wireless network in China. The measurement sites have been chosen with special care; thus the whole measured route can be characterized either by viaduct or terrain cutting. Kolmogorov-Smirnov (K-S) test has been first introduced in the statistical analysis to find out which is the most appropriate model for the small scale fading envelope. Though both Rice and Nakagami distributions provide a good fit to the first-order envelope data in both scenarios, only the Rice model generally fits the second-order statistics data accurately. For the viaduct scenario, higher Rice K factor can be observed. The change tendency of the K factor as a function of distance in the two scenarios is completely different. It can be concluded that the over bridges which span the railway tracks in terrain cutting scenario would affect the Rice K value severely.