nández-Durán are with Alcatel-Lucent.

Long Term Evolution (LTE) is considered to be the natural evolution for the current Global System for Mobile Communications–Railways (GSM‐R) in high speed railway environments, not only for its technical advantages and increased performance, but also due to the current evolution of public communication systems. In railway environments, mission critical services, operation assistance services, and passenger services must be supported by reliable mobile communication systems. Reliability and availability are key concerns for railway operators and as a consequence, railway operators are usually conservative adopters of information and communication technologies (ICT). This paper describes the feasibility of LTE as a successor to GSM‐R for new railway mobile communication systems. We identify key features of LTE as a technology and analyze its ability to support both the migration of current railway services and the provisioning of potential future ones. We describe the key challenges to address specific requirements for railway communication services including the provisioning of voice service in LTE networks, handover performance, multicast multimedia transmission, and the provisioning of group communications service and railway emergency calls. © 2013 Alcatel‐Lucent.

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Abstract. In this article, a novel approach to deal with the design of in-building wireless networks deployments is proposed. This approach known as MOQZEA (Multiobjective Quality Zone Based Evolutionary Algorithm) is a hybrid evolutionary algorithm adapted to use a novel fitness function, based on the definition of quality zones for the different objective functions considered. This approach is conceived to solve wireless network design problems without previous information of the required number of transmitters, considering simultaneously a high number of objective functions and optimizing multiple configuration parameters of the transmitters.

The volume of traffic generated in indoor environments is increasing exponentially, and emerging femtocell networks are being deployed to meet associated challenges. These specific in‐building deployments provide an opportunity for improving the performance of indoor positioning systems. Femtocell networks can be used to support accurate and reliable location services based on received‐ power and fingerprint location techniques. In fingerprint positioning methods, calibration and recalibration procedures are extremely time‐consuming tasks. To address this problem, we developed a novel scenario‐dependent procedure that reduced calibration points. We also analyzed several indoor propagation models, evaluating their suitability to reduce the effort required for calibration as well as their applicability for the recalibration procedures necessary to update previously recorded fingerprints. Our procedure includes both a simulation and a measurement phase, and obtains important improvements in accuracy, precision, and reliability while reducing the time and effort associated with both calibration and recalibration procedures. © 2013 Alcatel‐Lucent.

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SUMMARYThis paper assesses the main challenges associated with the propagation and channel modeling of broadband radio systems in a complex environment of high speed and metropolitan railways. These challenges comprise practical simulation, modeling interferences, radio planning, test trials and performance evaluation in different railway scenarios using Long Term Evolution (LTE) as test case. This approach requires several steps; the first is the use of a radio propagation simulator based on ray-tracing techniques to accurately predict propagation. Besides the radio propagation simulator, a complete test bed has been constructed to assess LTE performance, channel propagation conditions and interference with other systems in real-world environments by means of standard-compliant LTE transmissions. Such measurement results allowed us to evaluate the propagation and performance of broadband signals and to test the suitability of LTE radio technology for complex railway scenarios.

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