Validation of a communication standard between detectors and telecontrol systems in the railway enviroment

The railway environment relies over several detection systems to provide a secure trans- portation; some of these devices are the lateral wind detector, fallen object detectors, weather stations, vertical impacts detector, among many others. Each device provides particular functionalities and claims its own communication requirements. Given the complexity of a telecontrol system, a homogeneous communication solution supposes an improvement tool in terms of eficiency and future growth of the network, allowing connection capability with open systems, supplier independence and reducing installation and maintenance costs. This project includes a classification of the detection systems in the railway environ- ment to be aware of their complexity, in addition, issues related to remote systems and transport SCADA protocols are summarized. Further on the study, some general concepts related to this project's scenario must be described to comprehend the communication between detection and control systems and provide a standard solution for the communication of the current detection systems in the railway environment. Once analyzed the requirements, the solution that better suites characteristics such as standardization, interoperability, scalability and extensibility is the IEC 60870-5-104 communication standard. To adapt this technology to the railway control environment a data model specification was developed to integrate each particular detection protocol and facilitates the development of the implementation to validate the communication between the local operation points and the technical buildings. The addressing architecture is described to take advantage of the protocol's bene- fits, considering the necessary modifications in the control centres equipment according to each addressing plan; also the database model created to adapt the information from each detector studied previously to the desired standard will be described and finally the applications developed as test model to validate the specification of the selected standard for its use in railways detection systems are explained

Validation of a communication standard between detectors and telecontrol systems in the railway enviroment

The railway environment relies over several detection systems to provide a secure trans- portation; some of these devices are the lateral wind detector, fallen object detectors, weather stations, vertical impacts detector, among many others. Each device provides particular functionalities and claims its own communication requirements. Given the complexity of a telecontrol system, a homogeneous communication solution supposes an improvement tool in terms of eficiency and future growth of the network, allowing connection capability with open systems, supplier independence and reducing installation and maintenance costs. This project includes a classification of the detection systems in the railway environ- ment to be aware of their complexity, in addition, issues related to remote systems and transport SCADA protocols are summarized. Further on the study, some general concepts related to this project's scenario must be described to comprehend the communication between detection and control systems and provide a standard solution for the communication of the current detection systems in the railway environment. Once analyzed the requirements, the solution that better suites characteristics such as standardization, interoperability, scalability and extensibility is the IEC 60870-5-104 communication standard. To adapt this technology to the railway control environment a data model specification was developed to integrate each particular detection protocol and facilitates the development of the implementation to validate the communication between the local operation points and the technical buildings. The addressing architecture is described to take advantage of the protocol's bene- fits, considering the necessary modifications in the control centres equipment according to each addressing plan; also the database model created to adapt the information from each detector studied previously to the desired standard will be described and finally the applications developed as test model to validate the specification of the selected standard for its use in railways detection systems are explained

Is the random access channel of LTE and LTE-A suitable for M2M communications? A survey of alternatives

The 3GPP has raised the need to revisit the design of next generations of cellular networks in order to make them capable and efficient to provide M2M services. One of the key challenges that has been identified is the need to enhance the operation of the random access channel of LTE and LTE-A. The current mechanism to request access to the system is known to suffer from congestion and overloading in the presence of a huge number of devices. For this reason, different research groups around the globe are working towards the design of more efficient ways of managing the access to these networks in such circumstances. This paper aims to provide a survey of the alternatives that have been proposed over the last years to improve the operation of the random access channel of LTE and LTE-A. A comprehensive discussion of the different alternatives is provided, identifying strengths and weaknesses of each one of them, while drawing future trends to steer the efforts over the same shooting line. In addition, while existing literature has been focused on the performance in terms of delay, the energy efficiency of the access mechanism of LTE will play a key role in the deployment of M2M networks. For this reason, a comprehensive performance evaluation of the energy efficiency of the random access mechanism of LTE is provided in this paper. The aim of this computer-based simulation study is to set a baseline performance upon which new and more energy-efficient mechanisms can be designed in the near future.Peer Reviewe

Terrain-aided navigation of an underwater vehicle

SIGLEAvailable from British Library Document Supply Centre-DSC:D200183 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Multi-radio cooperative retransmission scheme for reliable machine-to-machine multicast services

Mobile Machine-to-Machine (M2M) market is expected to grow dramatically in the upcoming years; predictions agree that the majority of wireless traffic will correspond to this type of communication. M2M devices deployed in proximity to each other might be handled as groups or clusters when sharing the same communication attributes and serving to achieve joint target. Moreover, devices that feature multiple radio interfaces are commonly used nowadays; they can be connected to a cellular access network, e.g., LTE, and simultaneously to a short-range network, also known as capillary network, among surrounding devices, e.g., Wi-Fi and ZigBee. For services such as over-the-air (OTA) firmware update, the same information shall be sent to all the group members over the cellular access network. A Multi-Radio Cooperative Retransmission Scheme for Reliable Multicast Services is presented as a solution to reliably manage reception errors occurred over the cellular network; by carrying out retransmissions over a short-range network it is possible to reduce both the traffic load over the cellular link and the energy consumption in error recovery. Ns-3 simulations were performed with LTE network models to analyze the scheme in terms of energy consumption and prove its usefulness in autonomous, battery driven, devices.Peer Reviewe

Experimental study of Bluetooth, ZigBee and IEEE 802.15.4 technologies on board high-speed trains

This paper studies the feasibility of using low-power wireless technologies such as Bluetooth, IEEE 802.15.4 and ZigBee in high-speed railway scenarios that involve bidirectional ground-to-train communication. The presented results have been obtained through experimental tests conducted at the Madrid-Barcelona high-speed rail line. A multiplatform communication system has been installed in a high-speed train, circulating at velocities up to 300 km/h, whereas autonomous devices have been disseminated along of the railway path to communicate with the onboard devices. The conclusions drawn from this work will be used as guidelines for the future implementation of autonomous communication platforms for high-speed rail connectivity.Peer ReviewedPostprint (published version

Experimental study of bluetooth, ZigBee and IEEE 802.15.4 technologies on board high-speed trains

This paper studies the feasibility of using low-power wireless technologies such as Bluetooth, IEEE 802.15.4 and ZigBee in high-speed railway scenarios that involve bidirectional ground-to-train communication. The presented results have been obtained through experimental tests conducted at the Madrid- Barcelona high-speed rail line. A multiplatform communication system has been installed in a high-speed train, circulating at velocities up to 300 km/h, whereas autonomous devices have been disseminated along of the railway path to communicate with the onboard devices. The conclusions drawn from this work will be used as guidelines for the future implementation of autonomous communication platforms for high-speed rail connectivity.Peer Reviewe

Experimental study of bluetooth, ZigBee and IEEE 802.15.4 technologies on board high-speed trains

This paper studies the feasibility of using low-power wireless technologies such as Bluetooth, IEEE 802.15.4 and ZigBee in high-speed railway scenarios that involve bidirectional ground-to-train communication. The presented results have been obtained through experimental tests conducted at the Madrid- Barcelona high-speed rail line. A multiplatform communication system has been installed in a high-speed train, circulating at velocities up to 300 km/h, whereas autonomous devices have been disseminated along of the railway path to communicate with the onboard devices. The conclusions drawn from this work will be used as guidelines for the future implementation of autonomous communication platforms for high-speed rail connectivity.Peer Reviewe

Characterisation and modelling of 2.3 GHz in-building radio channels

Available from British Library Document Supply Centre- DSC:DX181299 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

An experimental study of multi-radio platform coexistence in the 5 GHz band for railway applications

This paper studies the practical challenges that arise due to the coexistence of two wireless technologies, both operating in the license-exempt 5 GHz band. In particular, WiFi and WiMAX equipment have been used in the experiments. The mutual interference caused by the two technologies operating in different but narrowly separated frequency channels has a negative impact on the performance of both systems. Further challenges are introduced when the two systems are in close physical proximity of each other or, in a more extreme scenario, share the same antenna as could be required in railway applications. This paper investigates these issues through a series of experimental tests based on a multi-radio platform testbed. The conclusions drawn from this study will be used as a base for the implementation of a multi-radio platform to provide communications between train and land in both directions in the context of the Spanish high-speed railway system.Peer Reviewe