Research On Performance Enhancement Technology Of Wireless Communication For Heavy Haul Railway

In order to greatly raise the transporting capability of a single freight train, the heavy haul railway transportation is a certain developing decision in the world railway industry. The train weighs over10thousand tons needs to be pulled by multiple locomotives, which is controlled by LOCOTROL system. The LOCOTROL system requires high communication reliability and real-time ability. Generally, existing control system will have a good performance if the train runs in the plain open area. However, the connecting rate reduces in mountain area where there are a large number of communication dead zones. Therefore, how to further enhance the communication reliability for locomotives of a train is a problem to be solved. On the other side, while the reliability is guaranteed, the coverage efficiency of the cells should also be improved to save energy and reduce the cost of communication facility construction,In other to save energy and reduce the cost of communication facility construction, this paper studies the coverage efficiency of radio-over-fiber network for heavy haul railway. Coverage efficiency is determined by calculating the area power consumption of cell according to combined path loss and shadowing model. Then, the relation between coverage efficiency and the proportion of antennas installed on the roof of train and RAUs is analyzed. Afterwards, the optimal proportions of train antennas and RAUs for corresponding interval of separation distance of train antennas and different marshalling types are provided.In other to improve the communication reliability between locomotives, mobile relay technology is adopted and a GSM-R based mobile relay enhanced wireless communication mechanism for heavy haul train is designed in this paper. In this mechanism, mobile relays will cooperate with GSM-R network to process the communication between locomotives. The communication quality of the new mechanism is verified by an empirical propagation models. Colored Petri Net (CPN) models are built for traditional mechanism and mobile relay enhanced mechanism respectively, and simulations are made to compare the communication reliability between the two mechanisms. The experiment results show that the mobile relay enhanced mechanism can basically meet the communication reliability requirement of LOCOTROL system. Furthermore, the new mechanism can significantly improve the communication reliability compared to GSM-R mechanism.