With the anticipation of Positive Train Control (PTC), as well as many other advanced rail applications, a modern end-to-end communication network infrastructure has become an essential requirement for the North American railroad industry. One focus area is on wireless technologies for track-side and yard deployments. Among the available broadband technologies, Mobile WiMAX has emerged as the most favorable solution for deployment in such an environment. It provides high throughput, large coverage and the support for many diverse applications, with attractive features like seamless handover, Quality-of-Service (QoS), the recovery from packet loss through mechanisms like Hybrid-Automatic Repeat reQuest (H-ARQ) and vehicular mobility support.
In this paper, we provide an overview of our research endeavors in evaluating Mobile WiMAX. We discuss our design and implementation of Mobile WiMAX computer model based on Network Simulator 2 (NS-2), which can simulate sophisticated scenarios frequently encountered by the railcars. We describe our experience in setting up our WiMAX testbeds in Ashland, NE and Logan, IA, utilizing the infrastructure from BNSF and UP in those locations, respectively. Since our test beds serve as prototypes, similar design principles can be applied for the eventual large-scale nationwide network deployment by the railroad industry. Furthermore, we present laboratory and field test results that clearly validate our design principles and demonstrates the advantages of Mobile WiMAX deployments for railroad operations.