Propagation Characteristic Estimations of 5GHz-band Wireless Links in High-Speed Train Cars Using FDTD Analysis

Masami SHIRAFUNE  Takashi HIKAGE  Toshio NOJIMA  Motoharu SASAKI  Wataru YAMADA  Takatoshi SUGIYAMA  

B - Abstracts of IEICE TRANSACTIONS on Communications (Japanese Edition)   Vol.J97-B   No.9   pp.762-769
Publication Date: 2014/09/01
Online ISSN: 1881-0209
Type of Manuscript: Special Section PAPER (Special Section on Antennas and Propagation Technologies Supporting the Foundations of Wireless Systems)
wireless LAN,  high-speed train cars,  propagation characteristics,  large-scale FDTD analysis,  

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The aim of this study is to accurately estimate 5 GHz electromagnetic field (EMF) distributions in high-speed train cars by means of a large scale FDTD simulation technique. The EMF is created by a Wireless-LAN (WLAN) access-point antenna placed in a train car. The problem space consists of two connected cars in which only one antenna is used and the characteristics of EMF penetration into the non-antenna equipped car are analyzed as well. The estimations consider the effects of passenger occupancy rate on the EMF distributions. In order to estimate the effect of the occupancy rate statistically, we derive simplified histograms of the electric field distributions throughout the entire interior of the cars. We compare the propagation characteristics of the 5 GHz wireless transmitter inside the cars with those of a 2 GHz device based on the modes of the histograms. The increasing ratio of attenuation with occupancy rate in 5 GHz is comparable to that in 2 GHz. The result shows the effectiveness of using 5 GHz-band as same as 2 GHz-band for wireless LAN implementation in high-speed train cars.