A survey on vehicular cloud computing

In recent years, the range of sensing technologies has expanded rapidly, whereas sensor devices have become cheaper. This has led to a rapid expansion in condition monitoring of systems, structures, vehicles, and machinery using sensors. Key factors are the recent advances in networking technologies such as wireless communication and mobile ad hoc networking coupled with the technology to integrate devices. Wireless sensor networks (WSNs) can be used for monitoring the railway infrastructure such as bridges, rail tracks, track beds, and track equipment along with vehicle health monitoring such as chassis, bogies, wheels, and wagons. Condition monitoring reduces human inspection requirements through automated monitoring, reduces maintenance through detecting faults before they escalate, and improves safety and reliability. This is vital for the development, upgrading, and expansion of railway networks. This paper surveys these wireless sensors network technology for monitoring in the railway industry for analyzing systems, structures, vehicles, and machinery. This paper focuses on practical engineering solutions, principally, which sensor devices are used and what they are used for; and the identification of sensor configurations and network topologies. It identifies their respective motivations and distinguishes their advantages and disadvantages in a comparative review.

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Wireless Sensor Networks for Condition Monitoring in the Railway Industry: A Survey

一种高速调制解调器，它通过电话线发送和接收一载频集的数字数据。 该调制解调器包括在载波之间可变地分配数据和功率，以便补偿等效噪声和使数据速率最大的系统。 此外，也介绍不需要一个均衡网络、可自适应地分配信道的控制和可跟踪线上参数变化的系统。

Ensemble modem structure for imperfect transmission media

Various wireless communication systems exist, which enable a wide range of applications and use cases in the vehicular environment. These applications can be grouped into three types, namely, road safety, traffic efficiency, and infotainment, each with its own set of functional and performance requirements. In pursuance of assisting drivers to travel safely and comfortably, several of these requirements have to be met simultaneously. While the coexistence of multiple radio access technologies brings immense opportunities towards meeting most of the vehicular networking application requirements, it is equally important and challenging to identify the strength and weaknesses of each technology and understand which technology is more suitable for the given networking scenario. In this paper, we evaluate two of the most viable communication standards, Institute of Electrical and Electronics Engineers (IEEE) 802.11p and long-term evolution (LTE) by 3rd Generation Partnership Project for vehicular networking. A detailed performance evaluation study of the standards is given for a variety of parameter settings such as beacon transmission frequency, vehicle density, and vehicle average speed. Both standards are compared in terms of delay, reliability, scalability, and mobility support in the context of various application requirements. Furthermore, through extensive simulation-based study, we validated the effectiveness of both standards to handle different application requirements and share insight for further research directions. The results indicate that IEEE 802.11p offers acceptable performance for sparse network topologies with limited mobility support. On the other hand, LTE meets most of the application requirements in terms of reliability, scalability, and mobility support; however, it is challenging to obtain stringent delay requirements in the presence of higher cellular network traffic load.

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LTE and IEEE 802.11p for vehicular networking: a performance evaluation

This paper presents a novel and practical study on the position-based radio propagation channel for High-Speed Railway by performing extensive measurements at 2.35 GHz in China. The specification on the path loss model is developed. In particular, small scale fading properties such as K-factor, Doppler frequency feature and time delay spread are parameterized, which show dynamic variances depending on the train location and the transceiver separation. Finally, the statistical position-based channel models are firstly established to characterize the High-Speed Railway channel, which significantly promotes the evaluation and verification of wireless communications in relative scenarios.

Position-Based Modeling for Wireless Channel on High-Speed Railway under a Viaduct at 2.35 GHz

This article presents a telecommunication network architecture based on mobile worldwide interoperability for microwave access (WiMAX) technology that fulfills the telecommunications needs in the railway domain.

WiMax on Rails

With the increment of passenger railway traffic especially in high speed lines, improvements in railway transportation safety become even more crucial. This paper presents technological and commercial trends in this area, enumerates innovative on-going related projects and proposes the application of new wireless communication standards such as, DSRC - WAVE (Dedicated Short Range Communications and Wireless Access in Vehicular Environment) or 802.11p; 802.16 or WiMAX; and MBWA (Mobile Broadband Wireless Access) or 802.20, in train control communications networks. In order to validate this proposal, we have designed a model for a wireless communication system deployed in a fully redundant configuration. The application of these new open-standard technologies will allow an affordable deployment, ubiquitous, always-on and interoperable muti-vendor mobile broadband train control communication system that supports new safety services and applications. Railway, signaling, wireless, 802.11b/g, MBWA

Railway signaling systems and new trends in wireless data communication

One of the key research issues in further strengthening the role of railways in the transportation system is to achieve the highest possible level of cyber security against significant threats to the signaling and telecom systems. The European Rail Traffic Management System (ERTMS) was designed in the 1990s with the security measures and strategies available at the time. However, ERTMS’ underlying communication technology, GSM-R, needs replacing, and replacement strategies are already underway. Due to their direct effects on safety, ERTMS security mechanisms also need updating to face current security threats. This article provides a security analysis of ERTMS’ safety layer, Euroradio, in terms of current security threats. After identifying its vulnerabilities, we present four main recommendations: a more robust cryptographic mechanism, a new key distribution scheme, a new key storage and system integrity module, and a set of countermeasures for avoiding radio jamming attacks.

Cyber security analysis of the European train control system

Reliability is a key research issue to promote the role of rail in the transportation system. An important set of critical and vital railway services, such as Traction Power Supply and Supervision Systems, relay currently on modern Supervisory Control and Data Acquisition (SCADA) systems. At the same time, these large scale and networked SCADA systems are deployed over heterogeneous wide area networks. Current strategies to warrant reliability on these systems focus on costly equipment redundancy or retransmission techniques with associated delay penalization. In this paper, we propose a MultiPath strategy with redundant policy to increase reliability in railway SCADA over TCP/IP systems. We built a hybrid simulation tool with real Modbus over TCP/IP equipment and validate our approach comparing the obtained results with three alternative strategies (default TCP/IP, backup and default delivery policy).

SCADA Systems in the Railway Domain: Enhancing Reliability through Redundant MultipathTCP

This article presents a mobile WiMAX network deployment as a candidate for broadband and low latency V2I communication architecture. Firstly, it looks over the current state of development of the standards involved, outlining the newest trends (i.e. 802.16m support for 500 km/h). Secondly, the opportunities and the main characteristics that this technology offers are highlighted. Thirdly, by stressing this network in two highly demanding scenarios, the challenges that this WiMAX network deployment faces are also identified. Network simulation modeling techniques have been used to carry out the corresponding performance analysis. The inter ASN handover is identified as the critical point to be tackled, so that, the proposed mobile WiMAX architecture meets the WiMAX radio system profile release 1.0 and RNM (reference network model) requirements when the class 2 group real time applications (VoIP & video conference) are deployed.

Marina Aguado

Papers

WiMax on Rails

Railway signaling systems and new trends in wireless data communication

Cyber security analysis of the European train control system

SCADA Systems in the Railway Domain: Enhancing Reliability through Redundant MultipathTCP

The WiMAX ASN Network in the V2I Scenario