Influence of Typical Railway Objects in a mmWave Propagation Channel

Abstract

In the future railway services, wireless communication is the fundamental part and millimeter wave (mmWave) is foreseen to be a key enabler towards the smart railway. An accurate understanding of the propagation environment can assist designing both systems and railway infrastructures for better communication services. In this paper, the influence of typical objects to the mmWave propagation channel are analyzed for "Train-to-infrastructure" and "Intra-wagon" railway scenarios with various configurations. Propagation measurements are conducted in the mmWave band for the 12 most common railway materials. The corresponding electromagnetic parameters are obtained and a 3D ray tracing (RT) simulator is calibrated. The mean absolute error of the simulated S21 parameter is-53.5 dB, indicating that the calibrated RT can be used to generate the close-to-real mmWave channel for railway scenarios. Statistically consistent scenarios and deployments are generated, which enables drawing unbiased numerical results based on intensive RT simulations. The influence of typical objects and corresponding material compositions are then compared and significant objects are determined for each scenario. The results of this work not only imply how the propagation environment impacts on the propagation channel, but also makes suggestions to efficiently reconstruct railway environment models for an accurate RT based channel model. Moreover, the understanding of the influence of the environment at object and material levels will in turn guide the construction of railway infrastructure for better railway services.

Millimeter Wave Channel Measurements in an Intra-Wagon Environment

“…In [1] and [2], at least five future railway service scenarios have been defined, including: train-to-infrastructure, inter-wagon, intra-wagon, inside-the-station, and infrastructure-toinfrastructure. There have been many recent studies on the mmWave band involved in both outdoor [2], [4]- [6], and indoor railway scenarios [6], [7]. In [2], channel measurements for inter-wagon communications have been performed at 64.5 GHz.…”

“…In [5], the authors have analyzed several propagation parameters using a 3D ray tracer in a train-to-infrastructure scenario at 25.25 GHz. In [6], the influence of typical railway objects in the propagation channel has been investigated using ray tracing techniques. However, with the exception of [7], there are no published works in which some aspects of the propagation channel in intra-wagon environments are analyzed from real measurements.…”

Realizing Multi-Gbps Vehicular Communication: Design, Implementation, and Validation

“…Temporal channel variation characteristics of the mmWave-based vehicular system were investigated in [14], where the impact of beamwidth was analyzed using the concept of beam coherence time. Channel models for high speed train moving at a speed up to 500 km/h were developed for various railway environments using 3D ray tracing simulations [15], [16]. Ray tracing-based channel modeling was also conducted for the mmWave-based V2X communications, showing the effects of beam alignment and beamwidth [17].…”

MC‐GiV2V: Multichannel Allocation in mmWave‐Based Vehicular Ad Hoc Networks

“…In [34], research results on propagation characteristics for V2V channels, particularly shadowing effects induced by obstructing vehicles between transmitter (Tx) and receiver (Rx), are introduced. In [35], measurement campaign is conducted in the mmWave band for the 12 most common railway materials; influence of typical objects to the mmWave propagation channel is analyzed for railway scenarios with various configurations. Reference [36] proposes an IEEE 802.11ad-based radar for long-range radar (LRR) applications at the 60 GHz unlicensed band, which enables a joint waveform for automotive radar and mmWave vehicle-tovehicle communications reusing hardware.…”