Channel sounding for high-speed railway communication systems

High-speed railway (HSR) communications have recently attracted much attention due to some specific railway needs, such as passenger experience services, business process support services, and operational data and voice services. The HSR radio channel, as a basis for the design of HSR communication systems and the evaluation of HSR communication technologies, has not yet been sufficiently investigated. This article focuses on radio channel sounding techniques for future HSR communication systems. Emphasis is placed on the fundamental features of measuring the HSR channel, and a review of the state of the art in HSR channel measurements is given. We also propose a novel LTE-based HSR channel sounding scheme and present results from our own measurement campaigns.