Modern society demands cheap, more efficient, and safer public transport. These enhancements, especially an increase in efficiency and safety, are accompanied by huge amounts of data traffic that need to be handled by wireless communication systems. Hence, wireless communications inside and outside trains are key technologies to achieve these efficiency and safety goals for railway operators in a cost-efficient manner. This paper briefly describes nowadays used wireless technologies in the railway domain and points out possible directions for future wireless systems. Channel measurements and models for wireless propagation are surveyed and their suitability in railway environments is investigated. Identified gaps are pointed out and solutions to fill those gaps for wireless communication links in railway environments are proposed.
Within the next decades the railway systems will change to fully autonomous high speed trains (HSTs). An increase in efficiency and safety and a reduction of costs would go hand in hand. Today's centralized railway management system and established regulations can not cope with trains driving within the absolute braking distance as it would be necessary for electronic coupling or platooning maneuvers. Hence, to ensure safety and reliability, new applications and changes in the train control and management are necessary. Such changes demand new reliable control communication links between train-to-train (T2T) and future developments on train-to-ground (T2G). T2G will be covered by long term evolution-railway (LTE-R) which shall replace today's global system for mobile communications-railway (GSM-R). The decentralized T2T communication is hardly investigated and no technology has been selected. This publication focuses on the wide band propagation for T2T scenarios and describes a extensive channel sounding measurement campaign with two HSTs. First results of T2T communication at high speed conditions in different environments are presented. Index Terms-train-to-train, high speed train, propagation, measurement.
The profound knowledge of wireless propagation is essential for wireless communication between vehicles. To evolve and test communication standards we need channel models in representative environments to neither over-, nor underestimate the effect of the surrounding environment and the movement of the vehicles; typical environments for railway communication are railway station, open field and hilly environments. We introduce train-to-train (T2T) path loss models and large scale fading statistics based on channel sounder measurement data as a first step towards a geometry-based stochastic channel model (GSCM). The models represent the mentioned typical environments for railway applications. We compare the results with previous published intelligent transportation system (ITS-G5) measurement based models and highlight the differences.
Within the next few decades, railways will undergo a major modernisation in order to increase their efficiency and safety. The modernisation process will enable new concepts such as fully autonomous trains and dynamic coupling of consists. Today's centralised railway management systems will not be able to safely handle these train concepts and, thus, will be replaced or complemented by new systems. These systems require a tight train monitoring which is based on the reliable exchange of information covering among others the accurate position and velocity of trains. The authors are sure that modern train concepts demand both reliable train‐to‐train (T2T) communication and improved capabilities for train‐to‐ground communication. However, T2T communication is hardly investigated and so far no technology has been selected. With this publication, the authors like to provide more insight into T2T signal propagation. This is the basis for the future development of a modern T2T communication system. The authors focus on wide band propagation for T2T scenarios and describe an extensive channel sounding measurement campaign involving two high speed trains. Results on signal propagation measurements in high speed T2T scenarios are presented for different environments. Hence, path loss models for rural, sub‐urban and tunnel environments are introduced.
Fundamental modernisation of railway transportation is on the agenda of the next generation train project funded by the German Aerospace Center DLR as well as the Roll2Rail project within the Shift2Rail initiative. Reliable direct train‐to‐train (T2T) communication can significantly enhance train control and signalling towards semi‐ or fully autonomous operation, in order to significantly increase the efficiency and safety. With terrestrial trunked radio a communication standard is available with high potential for this use‐case. It offers the ability of direct communications between vehicles, i.e. ad hoc communications over several kilometres. The authors summarise the results of T2T measurements conducted at 450 MHz. The authors will characterise the propagation conditions and assess the link performance by analysing transmissions in different scenarios and railway environments.
This paper explains the main results obtained from the research carried out in the work package 2 (WP2) of the Roll2Rail (R2R) project. This project aims to develop key technologies and to remove already identified blocking points for radical innovation in the field of railway vehicles, to increase their operational reliability and to reduce life-cycle costs. This project started in May 2015 and has been funded by the Horizon 2020 program of the European Commission. The goal for WP2 is to research on both technologies and architectures to develop a new wireless Train Communication Network (TCN) within IEC61375 standard series. This TCN is today entirely wired and is used for Train Control and Monitoring System (TCMS) functions (some of them safetyrelated), operator-oriented services and customer-oriented services. This paradigm shift from wired to wireless means a removal of wirings implies, among other benefits, a significant reduction of life cycle costs due to the removal of cables, and the simplification of the train coupling procedure, among others. IntroductionRailways are evolving very rapidly to meet the increasing demands of its users. Rolling stock is a cornerstone in this development, but there are some blocking points that need to be addressed. This is the main purpose of the EU-funded Roll2Rail (R2R) Project. Work package 2 (WP2) is focused on communication issues (which is one of the most challenging fields in railways [1]), and its final objective is to specify the requirements (and validate in a laboratory) for a wireless train communication network (TCN), at least with the same performance as the wired one. This wireless TCN would be very helpful to design, manufacture, operate and maintain trains from LCC (Life-Cycle Costs) point of view and able to avoid a significant number of failures due to broken connectors and cables. The partners in this WP were fourteen of the most relevant railway companies (see Table I), working as a single one.The first task to meet this goal is to clarify the state-of-theart of both radio technologies and related initiatives [2]. This review considered radio technologies and services, not only in railways, but also in the aeronautic, industry and automotive fields. Some of them have proven to be very useful in certain aspects (like GSM-R for train-to-ground communications), but they are unlikely to meet the requirements in other aspects. 3GPP LTE [3] and the IEEE 802.11 standards (commonly known as WiFi) [4] completed with deterministic communication features are two of the technologies that were identified as potential choices for the R2R project. Cognitive radio [5] is also a suitable approach that can help to achieve some of the objectives.The structure of the paper is the following one: in section II the general requirements that a Wireless TCMS needs to meet are depicted; in section III it is provided a model for each one of the radio channels of the project; in section IV, the security and reliability, availability, maintainability, and safety (RAMS) issues are...
Today’s railway network capacity is limited by constraints imposed by traditional train protection systems. A way to overcome those limitations, maximize the railway network performance and also increase the operational flexibility is presented by the Virtually Coupled Train Set (VCTS) concept. This paper evaluates the technical feasibility of this approach, that was developed and is further evaluated in the framework of the Shift2Rail (S2R) project X2Rail-3. The main functionality of virtually coupled train sets is achieved by replacing the mechanical coupler between two railway vehicles by an electronic (virtual) coupling link. This operational change requires a permanent vehicle-to-vehicle communication and precise distance measurement, while enabling much faster coupling and decoupling procedures, increased interoperability and the operation of trains with a headway below absolute braking distance. To evaluate the technical feasibility of the VCTS concept, a series of technical and operational subsystem have been identified and analyzed. Interviews with experts from a variety of VCTS linked topics have been conducted, to evaluate the state of the art and new developments for those subsystems. Subsequently, the capabilities of the subsystems have been compared with the requirements of the VCTS system. In addition, different mitigations to overcome possible obstacles have been identified and evaluated. As the result, the most critical technical aspects for the implementation and success of VCTS have been identified as the requirement of controllable, fast and accurate responding braking systems, the availability of suitable communication technologies and frequency bands, the need for highly-accurate measurement of distance, speed and acceleration and the fast detection and monitoring of train integrity. Considering those results, a qualitative roadmap for the future VCTS development and introduction strategy is derived.
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.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.