An OFDM-Based Transceiver Analysis for Railroad Applications.

The proliferation of wireless technologies in recent years has significantly impacted the North American freight railroad industry, and enabled them to drastically expand their communications capabilities for various railroad applications. The main challenge they now face, however, is the extreme congestion of radio-frequency (RF) spectrum resources, including those licensed by the railroad industry. Hence, the railroad industry is increasingly interested in investigating underutilized RF spectrum bands, such as the 160 MHz RF band. Due to the advantages of multi-carrier communications systems over single-carrier approaches, in this paper we present our simulation results for the performance of an Orthogonal Frequency Division Multiplexing (OFDM)-based communications system designed for 160MHz and its evaluation for different railroad environments. The transceiver design follows an implementable software-defined radio operation while conforming with regulatory requirements for the 160 MHz band. Our investigation presents the performance of QAM modulation ranging from 4QAM to 256QAM utilizing the Two-Ray ground reflection, Hata, and Winner 2 models to represent different railroad environments. In this investigation we analyze the simulated throughput versus distance for each modulation scheme and channel model to determine the maximum achievable communication distance before throughput deterioration. In order to verify the performance of our developed OFDM-based transceiver we compare our simulation results with the theoretical throughput for each modulation scheme under the considered channel models. The findings in this study will assist with the performance predictions of 160 MHz-based transceivers for additional railroad applications.