Research On The EMS Characteristics Of TD-LTE Vehicle-mounted Subsystems In The High-speed Railway

As the next generation of broadband mobile communication technology, TD-LTE will be applied to the next generation integrated mobile communication system of railway. In order to avoid the electromagnetic interference to degrade performance and security of TD-LTE vehicle subsystem, it’s necessary to analyze Electro Magnetic Compatibility (EMC) of TD-LTE system in the complex electromagnetic environment of electrified railway.Electro Magnetic Susceptibility (EMS) of TD-LTE system is researched in the thesis, when the system is applied in high-speed railway environment. Firstly, electromagnetic environment in the high-speed electrified railway is analyzed based on three elements of EMC. The pantograph and catenaries’offline noise from RF band is found to be the mainly electromagnetic interference for TD-LTE system. Secondly, combined with theoretical models of electrostatic discharge and lightning discharge, a new theoretical model of pantograph and catenaries’offline signal is proposed based on the qualitative analysis of previous, which reflects the physical characteristics of offline signal directly. Then a transient far field model of the offline signal is established, based on the Maxwell electromagnetic theory. Further research focuses on the transient characteristics of offline signal. Thirdly, based on the electromagnetic simulation software, the far field of the offline signal is simulated, which verifies the validity of the theoretical offline signal. Then combined with the measured data, the theoretical signal model and the transient far field model can be further confirmed. As the conclusion, the magnetic field from offline signal is certified to be weak, which is not enough to have an impact on signal equipment. At the same time, the electric field radiated from the offline signal is also not powerful enough, but further research is necessary for specific equipments. Finally, based on the theoretical research, simulated analysis and experimental data, the electromagnetic environment of TD-LTE vehicle subsystems in the high-speed railway is assessed. The results show that, for the TD-LTE system working in the frequency of1.88GHz～2.6GHz, the electromagnetic environment in high-speed railway affects the system weakly, but the further research is still necessary for specific equipments when applied. Based on the basic principle of EMC, the specific measures are put forward to suppress the electromagnetic interferences for TD-LTE vehicle subsystem in the high-speed railway.