Channel Characteristics in High-Speed Railway: A Survey of Channel Propagation Properties

In this article, we give an overview of recent research on propagation properties in high-speed railways (HSRs). The channel fading in HSRs is a big challenge for wireless access. It is essential to understand the channel-fading behavior before the system design. The novel results of propagation and channel models are presented. The details of channel characteristics, such as path loss, shadow fading, and Ricean K- factor, are discussed in each scenario. A comprehensive picture of propagation and channel-modeling research in railways is shown.