Study of RF Propagation Characteristics for Wireless Sensor Networks in Railroad Environments

2010PDFTech Report25-1121-0001-226Wireless LANsWireless communication systemsFreight serviceRailroadsSensorsFreight carsResearch HubUnited StatesMid-America Transportation CenterSharif, HamidHempel, MichaelUniversity of Nebraska at Omaha. Advanced Telecommunications Engineering LaboratoryMid-America Transportation CenterUS Transportation CollectionThe freight railroad industry in North America is exerting efforts to leverage Wireless Sensor Networks to monitor systems and components on railcars. This allows fault detection and accident prevention even while a train is moving. Railcars, constructed mostly of ferrous materials such as steel, are expected to severely impact signal propagation. To better understand this effect we first evaluated the signal characteristics when sensor nodes are placed in various locations around railcars. We used EM-Field modeling and evaluation techniques to obtain these results and found that node placement selection is critical for the node\u2019s communication distance. As a second research area we therefore aimed at understanding the protocol requirements and limitations of current WSN technologies. Based on the results of our study we found ZigBee to be inadequate for freight WSNs and developed a solution that remedies the problems we observed. Our evaluation of this new multi-tier approach shows a significant performance and network lifetime gain, making freight train wireless sensor networks feasible