Technical Reports

Providing Wireless Bandwidth for High-speed Rail Operations

  • 26
  • Jul
  • 2016
AUTHOR: Federal Railroad Administration
KEYWORDS: Positive train control, high-speed trains, bandwidth allocation and management, cell planning for high-speed trains
ABSTRACT: This project examined the possibility of providing wireless communication for train control systems on American high-speed trains. In this study, the key issue is that the frequencies allocated for rail operations in the U.S. and the frequencies used by GSM-R in other parts of the world have different capabilities. In Europe, GSM-R is transmitted over frequencies ranging from 800 MHz to 900 MHz. The U.S. has less bandwidth available with a lower frequency spectrum. This project was carried out in two phases: 1) A frequency analysis was done to see how the available frequency band should be divided to support train operations. For varying bit rates, modulation schemes and number of packets per handshake, models were developed to calculate the number of trains that a WIU can handle and the maximum speed the train can operate at, and 2) A detailed link budget analysis was used to calculate the received power level. Given that high-speed lines are currently not available, the project used SCRRA lines in Southern California and the Coast Starlight light rail line as case studies for the analysis. The locations of WIUs, points along the train line, and the terrain features were determined using existing maps; all of which were applied to calculate estimates of receive power for the train’s communications.