Based on the realistic channel measurement on High-Speed Railway (HSR) in viaduct scenarios at 2.35 GHz, the dynamic evolution of multipath components is investigated from the birth-death process point of view. Due to the distinction in the amount of resolvable multipath signals, the channel is divided into five segments and can be completely parameterized by several sets of statistical parameters associated with the type of environment and scenario. Then the four-state Markov chain, describing the birth-death number variation of the detected propagation waves, is employed to specialize the temporal stochastic properties. Furthermore, the steady probabilities and transition probabilities are provided which will facilitate the development and evaluation of wireless communication systems under HSR.
Wireless communication for high-speed railways (HSRs) that provides reliable and high data rate communication between the train and trackside networks is a challenging task. It is estimated that the wireless communication traffic could be as high as 65 Mbps per high-speed train. The development of such HSR communications systems and standards requires, in turn, accurate models for the HSR propagation channel. This article provides an overview of existing HSR channel measurement campaigns in recent years. Particularly, some important measurement and modeling results in various HSR scenarios, such as viaduct and U-shaped groove (USG), are briefly described and analyzed. In addition, we review a novel channel sounding method, which can highly improve the measurement efficiency in HSR environment.
This paper presents results from a wide band single-input-single-output (SISO) and 16 × 16 virtual multiple-input-multiple-output (MIMO) measurement campaign at a center frequency of 1.4725 GHz in a 100-meter long tunnel laboratory which is terminated by a vertical wall with a metallic door. The path loss, root-mean-square delay spread (RMS-DS) characteristics, and power delay profiles (PDPs) are described. In addition, we provide results for the MIMO channel amplitude matrix, which offers a new perspective in understanding MIMO characteristics in tunnel scenarios. Our measurement results are analyzed and compared to ray tracing simulations. The relationships among the angle spread, channel matrix singular values, and MIMO capacity at various link distances are illustrated, and these provide insights into MIMO system deployment.
This paper focuses on the analysis of propagation characteristics for train-ground communication (TGC) systems in tunnel scenarios at both low frequency and millimeter-wave (mmWave) bands, based on ray-tracing (RT) simulation. The material parameters in the RT simulation are calibrated by measurement data collected in realistic tunnel environments. A practical three dimension (3D) tunnel TGC environment considering the existence of train cars is established, which is further divided into three kinds of scenarios, involving the direct coverage, relay coverage, and in-train coverage scenarios. Both large-scale and small-scale propagation characteristics, such as path loss and root mean square delay spread, are analyzed for the three tunnel TGC scenarios. The obtained results can provide useful information for the design of future fifth-generation (5G) tunnel TGC systems.INDEX TERMS 5G, train-ground communications, channel modeling, propagation characteristics, millimeter-wave, and tunnel.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.