Testing of Zigbee System, Facing Unintentional and Intentional Electromagnetic Disturbances Present in Railway Environment

This paper deals with the performance of a sensor network system proposed to monitor and control freight trains, facing electromagnetic disturbances present in the railway environment. A study of existing technologies and systems demonstrated that a solution based on Zigbee technology is appropriate to our problem. A test bench, based on a hybrid coupler that sums the transmitted signal and the interfering one, was developed in order to measure the disturbances which can affect the on-board wireless communication systems. This measurement setup is used to physically simulate a telecommunication submitted to an electromagnetic disturbance but neglecting the contribution of the free propagation. The effect of the disruption of the sliding contact between the catenary and the pantograph on the Zigbee communication is studied. The impact of intentional electromagnetic interferences on communication performance is also analyzed and the relationship between the parameters of a jamming signal and the interruption of the Zigbee transmission is presented in the paper.