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    Definición de un sistema global de información en materia de discapacidad en la universidad : Observatorio Universidad y Discapacidad  Open access

     Guasch Murillo, Daniel; Hernández Galán, Jesús; Martin Escalona, Israel; Rico Novella, Francisco Jose; Guasch Murillo, Yolanda; Vállez Vidal, Raquel; Àlvarez Suau, Maria Hortènsia
    Date of publication: 2014
    Book

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    El estudio que se presenta a continuación aporta las reflexiones necesarias para empezar a trabajar en la consecución de un sistema de información que permita recopilar los datos estadísticos necesarios para extraer el conocimiento sobre la evolución del sistema universitario español. Demuestra la viabilidad legal, académica y técnica del sistema sin dudas ni lagunas. Aporta las especificaciones necesarias para su implementación. Y, finalmente, pone en manos de la voluntad la necesidad de su creación.

  • A topic on simulation in telecommunications engineering

     Barceló Arroyo, Francisco; Martin Escalona, Israel; Zola, Enrica Valeria
    IEEE Global Engineering Education Conference
    Presentation's date: 2014-04-03
    Presentation of work at congresses

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    Topics on network simulation are often offered as elective topics or short seminars of programs on computer sciences and telecommunications engineering. In other programs simulation is offered as part of a general core topic (e.g. probability and statistics, network performance, etc.). It is not frequent to find simulation as a core topic. At the Faculty of Telecommunications in Barcelona it was decided to include network simulation as a core topic in the former integrated master (5 academic years) on telecommunication engineering. This paper deals with the reasons after that decision. The goal of the paper is to present and discuss how the topic evolved through the years and how it has been migrated to the new careers with separated degree and master after the Bologna process.

    Topics on network simulation are often offered as elective topics or short seminars of programs on computer sciences and telecommunications engineering. In other programs simulation is offered as part of a general core topic (e.g. probability and statistics, network performance, etc.). It is not frequent to find simulation as a core topic. At the Faculty of Telecommunications in Barcelona it was decided to include network simulation as a core topic in the former integrated master (5 academic years) on telecommunication engineering. This paper deals with the reasons after that decision. The goal of the paper is to present and discuss how the topic evolved through the years and how it has been migrated to the new careers with separated degree and master after the Bologna process.

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    Positioning terminals in mobile computing networks  Open access

     Barceló Arroyo, Francisco; Martin Escalona, Israel; Ciurana Adell, Marc
    ERCIM news
    Date of publication: 2013-03-27
    Journal article

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  • Definir un sistema global de información en materia de discapacidad en la universidad

     Guasch Murillo, Daniel; Martin Escalona, Israel; Rico Novella, Francisco Jose; Guasch Murillo, Yolanda
    Participation in a competitive project

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  • Forecasting the next handoff for users moving with the Random Waypoint mobility model

     Zola, Enrica Valeria; Barceló Arroyo, Francisco; Martin Escalona, Israel
    Eurasip journal on wireless communication and networking
    Date of publication: 2013-01-25
    Journal article

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    Users in a cellular network can move while their connections are handed off to different access points. Studies prove that the mobility pattern followed have a strong impact on performance metrics (i.e., handoff (HO) rate, cell residence time). Recently, some key aspects of the Random Waypoint mobility model have been studied in depth, but relating those studies with different cellular layouts has not been reported. Interest in forecasting the cell to which a device may be handed off depending on the movement pattern is twofold. First, it gives insight into properties and statistics of the mobility model. Second, and from a more practical perspective, it is useful to manage resource allocation and reservation strategies in order to smooth the HO process. The goal of this article is to provide an analytical framework for these predictions in a simple layout. Given a node's current location and the timestamp and location of the last waypoint, an approximation for HO during time Delta t is derived. The analysis is provided along with numerical examples and simulations for a symmetrical layout and uniform speed distribution. Results shed light on how useful more advanced strategies can be.

  • A software platform for measuring distances through round trip time in IEEE 802.11

     Martin Escalona, Israel; Barceló Arroyo, Francisco; Zola, Enrica Valeria
    Wireless and Mobile Networking Conference
    Presentation's date: 2013-04-23
    Presentation of work at congresses

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    Indoor positioning has focused the interest of researchers for years. Although there are several techniques proposed, they are difficult to reproduce and consequently to contrast and improve. This paper presents a modular location platform, which enhances the SoftMAC implementation in Linux with positioning capabilities. This platform can be deployed in any device running Linux kernel 2.6 or higher. The core of the platform is its software-based measuring system. This measuring system supports the 2-way TOA technique, but any time-based multilateration technique (e.g. passive TDOA) can be incorporated with minimum changes. Real data have been gathered to assess the performance of the measuring system. The RTTs estimated grow with the distance, which demonstrates the feasibility of the system.

    Indoor positioning has focused the interest of researchers for years. Although there are several techniques proposed, they are difficult to reproduce and consequently to contrast and improve. This paper presents a modular location platform, which enhances the SoftMAC implementation in Linux with positioning capabilities. This platform can be deployed in any device running Linux kernel 2.6 or higher. The core of the platform is its software-based measuring system. This measuring system supports the 2-way TOA technique, but any time-based multilateration technique (e.g. passive TDOA) can be incorporated with minimum changes. Real data have been gathered to assess the performance of the measuring system. The RTTs estimated grow with the distance, which demonstrates the feasibility of the system.

  • The introduction of a topic on accessibility in several engineering degrees

     Martin Escalona, Israel; Barceló Arroyo, Francisco; Zola, Enrica Valeria
    IEEE Global Engineering Education Conference
    Presentation's date: 2013-03-13
    Presentation of work at congresses

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    Together with the trend towards engineering designs more accessible to handicapped people there is an increasing concern at the engineering faculties to include topics related to accessibility in their programs. Engineers must be aware that handicapped people use technology and designs must take into account this fact. This paper explains how a topic on accessibility was started at a technical faculty as a cross topic to five different engineering degrees: Electrical, Electronics and Automatic Control, Industrial Product Design, Electronic Systems and Computer Science. The introduction process is explained along with the teaching methodology. Results after the first two courses are good in general but present some issues. The main issue to be corrected is that students from different branches achieve different academic performances.

    Together with the trend towards engineering designs more accessible to handicapped people there is an increasing concern at the engineering faculties to include topics related to accessibility in their programs. Engineers must be aware that handicapped people use technology and designs must take into account this fact. This paper explains how a topic on accessibility was started at a technical faculty as a cross topic to five different engineering degrees: Electrical, Electronics and Automatic Control, Industrial Product Design, Electronic Systems and Computer Science. The introduction process is explained along with the teaching methodology. Results after the first two courses are good in general but present some issues. The main issue to be corrected is that students from different branches achieve different academic performances.

  • From integrated to international masters in engineering: the increase of heterogeneity

     Barceló Arroyo, Francisco; Martin Escalona, Israel; Zola, Enrica Valeria
    International Conference on Education and New Learning Technologies
    Presentation's date: 2013-07-01
    Presentation of work at congresses

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    This paper analyses the difficulties found in some countries in Europe were the traditional integrated masters of five or six academic years were split into degree plus master after the Bologna process. Often, the master years of the former integrated master are oriented to international students and the lecturers find a high degree of diversity not present in the degree (this latter in local language and targeted to local students, close to the former first years of the integrated master). A case belonging to a master in computer networks is discussed together with some facts, difficulties found during the first years, discussion and possible ways to solve some of the detected issues.

  • Linux-based measuring platform for time-based location observables in IEEE 802.11 networks

     Martin Escalona, Israel; Barceló Arroyo, Francisco; Zola, Enrica Valeria
    Joint ERCIM eMobility and MobiSense Workshop
    Presentation's date: 2013-06-04
    Presentation of work at congresses

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    Positioning has been a hot topic in research for several years. GPS is accepted as a global solution for positioning outdoors, but indoor positioning still remains an open issue. Time-based multilateration techniques are presented as a good trade-off between performance and complexity for indoor positioning. Although several proposals for time-based multilateration has been presented, only some of them has been really implemented and of them, only few can be reproduced by other researchers (mainly due to hardware customization). This work presents a system for measuring time-based location observables in IEEE 802.11 networks. This measuring system has been implemented in Linux, so it can be deployed easily by any researcher. The current implementation supports the measurement of two kind of observables: round trip times (for two-way time-of-arrival techniques) and passive TDOAs (for the passive TDOA location technique). First experiments, presented in this paper, are focused on demonstrating the feasibility of the system for measuring these two location observables.

    Positioning has been a hot topic in research for several years. GPS is accepted as a global solution for positioning outdoors, but indoor positioning still remains an open issue. Time-based multilateration techniques are presented as a good trade-off between performance and complexity for indoor positioning. Although several proposals for time-based multilateration has been presented, only some of them has been really implemented and of them, only few can be reproduced by other researchers (mainly due to hardware customization). This work presents a system for measuring time-based location observables in IEEE 802.11 networks. This measuring system has been implemented in Linux, so it can be deployed easily by any researcher. The current implementation supports the measurement of two kind of observables: round trip times (for two-way time-of-arrival techniques) and passive TDOAs (for the passive TDOA location technique). First experiments, presented in this paper, are focused on demonstrating the feasibility of the system for measuring these two location observables.

  • Software based measurement of round trip time observables for location in IEEE 802.11 networks

     Martin Escalona, Israel; Barceló Arroyo, Francisco; Zola, Enrica Valeria
    International Conference on Telecommunications
    Presentation's date: 2013-07
    Presentation of work at congresses

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    Time-based multilateration in IEEE 802.11 networks usually involves custom hardware designs, which tend to slow down the implementation and deployment of the location system. This paper presents software for calculating time-based location observables. This software enhances the SoftMAC layer of the Linux operating system by adding location-related measuring capabilities. A plugin for calculating the round trip time between two network entities is included in the software definition. Real data have been collected to test the performance of the proposed system. Despite the relevant noise present in the measurements, the results prove that the round trip time measurements achieved are useful to estimate distances achieving estimates with RMS of the error close to 2 meters.

    Time-based multilateration in IEEE 802.11 networks usually involves custom hardware designs, which tend to slow down the implementation and deployment of the location system. This paper presents software for calculating time-based location observables. This software enhances the SoftMAC layer of the Linux operating system by adding location-related measuring capabilities. A plugin for calculating the round trip time between two network entities is included in the software definition. Real data have been collected to test the performance of the proposed system. Despite the relevant noise present in the measurements, the results prove that the round trip time measurements achieved are useful to estimate distances achieving estimates with RMS of the error close to 2 meters.

  • Software-based system for measuring location observables in IEEE 802.11 networks

     Martin Escalona, Israel; Barceló Arroyo, Francisco; Zola, Enrica Valeria
    IEEE IFIP Annual Mediterranean Ad Hoc Networking Workshop
    Presentation's date: 2013-06-26
    Presentation of work at congresses

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    Several techniques have been proposed for positioning nodes over IEEE 802.11 networks, but only few consist in time-based multilateration, mainly due to the protocol stack not supporting accurate timestamps. One frequent solution is to develop the hardware required for providing accurate timestamps. However, this approach tends to slow down the research and the ulterior deployment of the location techniques, since the performance of these techniques is bounded to a specific hardware design. This paper presents a measuring system aimed at providing location observables that can be used in time-based multilateration techniques. The system, which follows a software approach, is based on enhancing the SoftMAC layer of Linux with location-measuring capabilities. The system is conceived for supporting any kind of time-based measurements, by adding as many plugins as measured observables. Two plugins have been initially developed. The first one computes the round trip time of a message from a station to an access point and back again to the station. The second plugin calculates time-differences of arrival suitable for being used in the passive TDOA technique. This work provides the definition of the measuring system. Real data has been collected to test the system. The results indicate that the measurements provided by the system can be used for location purposes, i.e. they follow the physical laws in which metrics are based (e.g. they grow along with the distance between the nodes).

  • Calculating distances between wireless nodes for wireless network localization

     Martin Escalona, Israel; Barceló Arroyo, Francisco; Ciurana Adell, Marc
    Recent Advances in Communications and Networking Technology
    Date of publication: 2012-12-01
    Journal article

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    This paper presents a patent targeted to obtain distance measurements between nodes belonging to a wireless network. The main motivation for this patent is the measurement of the distance between a user device and an access point (or base station). After several distance measurements to different access points at sight and assuming the position of the access points known, the device can compute its own position by trilateration. The main advantage in front of previously existing methods to obtain distance measurements is that the method presented here involves only software modifications to legacy terminals, thus allowing avoiding the need for hardware modifications at the user terminal.

  • Performance evaluation of the passive TDOA algorithm in dark areas

     Martin Escalona, Israel; Malpartida, Marta; Barceló Arroyo, Francisco
    International Conference and Exhibition on Ubiquitous Positioning, Indoor Navigation and Location Based Services
    Presentation's date: 2012-10-04
    Presentation of work at congresses

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    Positioning in wireless networks has recently concentrated the interest of the research community. Outdoor positioning has been addressed successfully, but location indoors poses some open issues. Time-based ranging techniques, such as 2-way time-of-arrival (TOA), are promising for indoor positioning but present issues such as scalability and landmark dependency. Handling these problems separately makes it difficult to find solutions that can be implemented over communication networks on which positioning solutions rely. The passive TDOA algorithm was proposed for overcoming both issues together. Preliminary results indicate that scalability can be improved. This work assesses the performance of the passive TDOA in scenarios where there are not enough landmarks to run a regular 2-way TOA algorithm. Results show that the accuracy provided is worse than in scenarios with enough landmarks but, depending on the power of the ranging noise, good enough for most of the location-based services indoors.

  • Impact of the range and geometry estimation in the accuracy of the passive TDOA algorithm

     Martin Escalona, Israel; Barceló Arroyo, Francisco; Zola, Enrica Valeria
    Annual Mediterranean Ad Hoc Networking Workshop
    Presentation's date: 2012-06-22
    Presentation of work at congresses

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    The positioning ability is essential in mobile networks. Providing the position of entities is in general a complex task that becomes especially hard in ad hoc networks. In these networks, the topology cannot be planned and network nodes usually present restrictions in terms of computation capabilities and autonomy that constrain the network lifetime. Passive algorithms have been proposed for minimizing the impact of location services in the network, i.e. reducing the location traffic and extending the network life. However, the accuracy of passive algorithms tends to be worse than the accuracy for active approaches. This paper studies the impact of several proposals focused on improving the accuracy of the passive TDOA algorithm. Results indicate that weighing the ordinary least squares algorithm with the appropriate factors could be enough for improving the accuracy of the algorithm in some scenarios.

  • Enhanced vehicle navigation unit with wifi 802.11 ranging and communication capabilities

     Tappero, Fabrizio; Ciurana Adell, Marc; Batlle, Jordi; Uijt de Haag, M.; Martin Escalona, Israel; Fernández Fernández, Daniel
    International Conference on Space Applications
    Presentation's date: 2012-06-25
    Presentation of work at congresses

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    This paper discusses the implementation of a modified IEEE 802.11 transceiver that is employed to enhance the positioning capabilities of a traditional vehicle on-board navigation unit (OBU). In this paper, we propose to use the current wireless local access network (WLAN) as enhancing infrastructure for ubiquitous localisation and positioning. We describe the architecture of a localisation receiver built around a FPGA that is capable of measuring the signal round trip time and thus distance between itself and visible WiFi access points. The proposed system has great potentials to enhance the performance of traditional hardware solutions often based on GNSS plus INS traditionally used as fundamental component in an intelligent transportation system. The proposed system offers vehicle-to-vehicle communication and ranging capabilities using the current IEEE 802.11 standard. This paper describes the details of the WLAN ranging estimation method, possible integration approaches with a GPS plus INS system and an analysis of the proposed system’s positioning performance in a crowded urban environment.

  • Study of the results in a heterogeneous group for a course on computer networks

     Barceló Arroyo, Francisco; Martin Escalona, Israel
    International Conference on Interactive Collaborative Learning
    Presentation's date: 2012-09-26
    Presentation of work at congresses

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    This paper shows statistics of a group at the Faculty of Telecommunications Engineering in Barcelona (Spain). Due to the different origin and academic background of the students, planning the course is a challenging task. This work shows the features that characterize the group as heterogeneous. Statistics about the origin and the grades of a test before the course are shown along with the existing correlation between both. The paper also analyzes the grades obtained in the final exams and relates them to the origin and initial test. In the statistics some groups can be differentiated with students belonging to each group showing a similar degree of academic progress. The results allow drawing some conclusions on how a careful observation of the countries of origin, academic background and the results of a test before starting the course can help to plan a balanced course and evaluation.

    This paper shows statistics of a group at the Faculty of Telecommunications Engineering in Barcelona (Spain). Due to the different origin and academic background of the students, planning the course is a challenging task. This work shows the features that characterize the group as heterogeneous. Statistics about the origin and the grades of a test before the course are shown along with the existing correlation between both. The paper also analyzes the grades obtained in the final exams and relates them to the origin and initial test. In the statistics some groups can be differentiated with students belonging to each group showing a similar degree of academic progress. The results allow drawing some conclusions on how a careful observation of the countries of origin, academic background and the results of a test before starting the course can help to plan a balanced course and evaluation.

  • Study of the results in a heterogenous group for a course on computer networks

     Barceló Arroyo, Francisco; Martin Escalona, Israel
    Interactive Collaborative Learning: International Conference on Interactive Collaborative Learning and International Conference on Engineering Pedagogy
    Presentation's date: 2012-09-28
    Presentation of work at congresses

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    This paper shows statistics of a group at the Faculty of Telecommunications Engineering in Barcelona (Spain). Due to the different origin and academic background of the students, planning the course is a challenging task. This work shows the features that characterize the group as heterogeneous. Statistics about the origin and the grades of a test before the course are shown along with the existing correlation between both. The paper also analyzes the grades obtained in the final exams and relates them to the origin and initial test. In the statistics some groups can be differentiated with students belonging to each group showing a similar degree of academic progress. The results allow drawing some conclusions on how a careful observation of the countries of origin, academic background and the results of a test before starting the course can help to plan a balanced course and evaluation.

  • Comparative performance evaluation of IEEE 802.11v for positioning with time of arrival

     Ciurana Adell, Marc; Barceló Arroyo, Francisco; Martin Escalona, Israel
    Computer Standards & Interfaces
    Date of publication: 2011-03
    Journal article

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    Time of Arrival (TOA) based techniques are expected to overcome performance limitations of existing WLAN positioning approaches. The upcoming IEEE 802.11v standard is expected to play a key role because it will include new specific mechanisms for TOA-based positioning with WLAN. This article analyzes some of these new capabilities and evaluates the performance enhancement that they can provide in practice. To this end, a comparative assessment between an existing WLAN TOA-based approach that uses IEEE 802.11 b/g and an analogous solution employing IEEE 802.11v is performed.

  • Sistema de localització de terminals sense fils WLAN a l' interior d'edificis

     Barceló Arroyo, Francisco; Martin Escalona, Israel
    Participation in a competitive project

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  • Middleware for positioning in cellular networks

     Martin Escalona, Israel; Barceló Arroyo, Francisco; Ciurana Adell, Marc
    Date of publication: 2011-04-23
    Book chapter

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  • Fusion of WLAN and GNSS observables for positioning in urban areas: the position ambiguity

     Fernández, Daniel; Barceló Arroyo, Francisco; Martin Escalona, Israel; Ciurana Adell, Marc; Jofre, Martí; Gutiérrez, Esteban
    IEEE Symposium on Computers and Communications
    Presentation's date: 2011
    Presentation of work at congresses

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    This paper proposes a positioning method that combines GPS pseudoranges and WLAN ranges when less than four GPS satellites are within sight. To enhance the positioning availability, a tight hybridization approach with both technologies is considered. Although the work has been performed considering WLAN and GPS, most of the presented ideas, procedures and results are also valid for generic tight non-synchronized fusion of GNSS with terrestrial signals. Special emphasis is placed on the phenomenon of positioning ambiguity that appears due to the combination of measurements with different characteristics. To solve this ambiguity, a method is proposed and studied. The availability and accuracy of the system are tested considering different satellite and terrestrial geometries. The results show that the proposed system is able to improve the availability while maintaining the accuracy of GPS as a standalone.

  • Analysis of a heterogeneous group belonging to an international master course on computer networks

     Barceló Arroyo, Francisco; Cruz Llopis, Luis Javier de La; Martin Escalona, Israel
    International Conference on Engineering and Computer Education
    Presentation's date: 2011-09-25
    Presentation of work at congresses

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  • A field study on the fusion of terrestrial and satellite location methods in urban cellular networks

     Barceló Arroyo, Francisco; Martin Escalona, Israel; Manente, Cyrille
    European transactions on telecommunications
    Date of publication: 2010-05-01
    Journal article

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    This work studies the improvement in service coverage obtained by three different approaches to combining two triangulation (terrestrial and satellite) location methods for cellular networks in an urban environment. The paper assumes that the terrestrial cellular network uses enhanced observed time difference (E-OTD) in 2G or observed time difference of arrival (OTDOA) in 3G, while the satellite GNSS uses the assisted global positioning system (A-GPS), but the analysis can be easily generalised to other triangulation methods. A straightforward analytical model is presented to evaluate the service coverage resulting from each of the three approaches. The model is fed with actual coverage figures, gathered from test measurements carried out in Paris (France) for several urban scenarios. Numerical results show that the three approaches lead to improvements in all the tested scenarios, and that the improvement obtained by the increasing complexity of the fusion approach depends highly on the coverage of each individual method and on the joint probability function of individual performances

  • Location in wireless Local Area Networks

     Ciurana Adell, Marc; Martin Escalona, Israel; Barceló Arroyo, Francisco
    Date of publication: 2010-07-01
    Book chapter

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    Discrete event simulation of wireless cellular networks  Open access

     Zola, Enrica Valeria; Martin Escalona, Israel; Barceló Arroyo, Francisco
    Date of publication: 2010-09
    Book chapter

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    Location in ad-hoc networks  Open access

     Martin Escalona, Israel; Ciurana Adell, Marc; Barceló Arroyo, Francisco
    Date of publication: 2010
    Book chapter

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  • Contributions to location in cellular networks

     Martin Escalona, Israel
    Defense's date: 2010-05-10
    Department of Telematics Engineering, Universitat Politècnica de Catalunya
    Theses

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  • ENCAMINAMIENTO PARA REDES AD-HOC BASADO EN LOCALIZACION DE TERMINALES. APLICACIONES Y SINERGIAS CON

     Rojas Espinosa, Alfonso; Martin Escalona, Israel; Zola, Enrica Valeria; Ciurana Adell, Marc; Barceló Arroyo, Francisco
    Participation in a competitive project

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  • Cost Action IC0906: Wireless Networking for Moving Objects (WiNeMO)

     Koucheryavy, Yevgeni; Martin Escalona, Israel; Barceló Arroyo, Francisco; Zola, Enrica Valeria
    Participation in a competitive project

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    Impacto del modelo de error en distancia en la simulación de sistemas de localización  Open access

     Guardiola, Salvador; Martin Escalona, Israel; Barceló Arroyo, Francisco; Ciurana Adell, Marc
    Jornadas de Ingeniería Telemática1
    Presentation's date: 2010-09
    Presentation of work at congresses

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    Las redes inalámbricas han favorecido enormemente el interés de los usuarios, proveedores de servicio y operadores de red en el posicionamiento geográfico. Como consecuencia, se han propuesto mecanismos en la mayor parte de tecnologías de red inalámbrica con los que soportar la localización de usuarios. La evaluación de calidad ofrecida por dichas técnicas de localización, normalmente en términos de precisión, latencia y escalabilidad, recae en herramientas de simulación. Es esencial por tanto, que los modelos de error empleados en estas herramientas estén acordes a la realidad. Este hecho es si cabe más importante en el caso de emplear técnicas de localización basadas en medida de la distancia a partir de métricas temporales, como son el tiempo de llegada (TOA) o la diferencia entre tiempos de llegada (TDOA). Estas técnicas son especialmente sensibles a no disponer de visión directa entre los distintos elementos involucrados en la localización, por lo que la evaluación de sus capacidades suele hacerse bajo esas condiciones. El presente artículo compara bajo un mismo escenario, diversos modelos de error para las métricas empleadas en técnicas como TOA o TDOA. Los resultados concluyen que los modelos que no tienen en cuenta las distancias reales (que son los más habituales) tienden a proporcionar una estimación optimista el error de posicionamiento, cosa que no ocurre en el caso de modelos más complejos que sí tienen en cuenta esa información.

  • Performance stability of software ToA-based ranging in WLAN

     Ciurana Adell, Marc; Giustiniano, Domenico; Neira, Albert; Barceló Arroyo, Francisco; Martin Escalona, Israel
    International Conference on Indoor Positioning and Indoor Navigation
    Presentation's date: 2010-09
    Presentation of work at congresses

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    This article proposes a set of strategies to improve the performance stability and reliability of purely software ToA-based ranging with off-the-shelf WLAN equipment. Taking as starting point the core design lines proposed in (1), where timing measurements were taken at OS level using the CPU clock of the client device, we optimize the OS configuration and the capture of the time-stamps. Results obtained with a prototype demonstrate that the proposed enhancements improve the performance stability by a factor four. The interest in this kind of ranging methods is because they enable cost-effective and accurate positioning in GNSSless environments.

  • Passive TDOA location in mobile ad-hoc networks

     Martin Escalona, Israel; Barceló Arroyo, Francisco
    International Conference on Ultra Modern Telecommunications
    Presentation's date: 2010-10
    Presentation of work at congresses

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  • A Field Study on Satellite and Cellular Signals as Sources for Location

     Gete-Alonso Roldan, Oscar; Martin Escalona, Israel; Barceló Arroyo, Francisco
    International Conference on Computer Engineering and Applications
    Presentation's date: 2010-03-20
    Presentation of work at congresses

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    This article presents a statistical study on the availability of location sources. In particular, it rates the availability of cellular network base stations and GPS satellites in urban scenarios. Individual and joint availability density functions have been obtained for both types of signal sources, as well as statistical information that complements these functions. This information is of great importance due to the growing interest in fusion (i.e., combination) of location techniques. The results indicate that the improvements in coverage from fusion techniques depend both on the fusion mechanism and the scenario, obtaining noticeable benefits in constrained situations.

  • On the Resolution of position ambiguity when integrating GNSS and WLAN observables

     Fernández, Daniel; Ciurana Adell, Marc; Jofre, Martí; Gutiérrez, Esteban; Chester, Edward Ian; Barceló Arroyo, Francisco; Martin Escalona, Israel
    European Navigation Conference on Global Navigation Satellite Systems
    Presentation's date: 2010-10-20
    Presentation of work at congresses

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  • Process and system for calculating distances between wireless node

     Martin Escalona, Israel; Barceló Arroyo, Francisco; Ciurana Adell, Marc
    Date of request: 2010-05-11
    Invention patent

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  • Procedimiento y sistema para el cálculo de distancias entre nodos inalámbricos

     Martin Escalona, Israel; Barceló Arroyo, Francisco; Ciurana Adell, Marc
    Date of request: 2010-04-16
    Invention patent

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  • A survey on classical teletraffic models and network planning issues for cellular telephony

     Barceló Arroyo, Francisco; Martin Escalona, Israel
    International journal of business data communications and networking
    Date of publication: 2009-09-10
    Journal article

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  • Chapter 4: Mobility Support

     Barceló Arroyo, Francisco; Aguayo-Torres, M.C.; Al Begain, K.; Martin Escalona, Israel; Vassilou, V.
    Date of publication: 2009-04-01
    Book chapter

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  • On the impact of ranging-error models for simulating indoors location systems

     Guardiola, Salvador; Martin Escalona, Israel; Barceló Arroyo, Francisco
    IEEE International Symposium on Personal, Indoor, and Mobile Radio Communications
    Presentation of work at congresses

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  • Sistema y procedimiento de localización basados en medidas pasivas de diferencias temporales para el posicionamiento conjunto de nodos en redes colaborativas

     Martin Escalona, Israel; Barceló Arroyo, Francisco
    Date of request: 2009-09-18
    Invention patent

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    Sistema y procedimiento de localización basados en medidas pasivas de diferencias temporales para el posicionamiento conjunto de nodos en redes colaborativas.

    Procedimiento destinado a obtener la localización conjunta de nodos en una red colaborativa de forma pasiva, basado en la existencia de un nodo (pasivo) que se posiciona a partir de las peticiones de localización realizadas por un subconjunto de nodos de la misma red (nodos activos), que emplean una técnica de localización basada en la estimación del tiempo de ida y vuelta. El procedimiento permite la estimación de los tiempos de propagación de los nodos activos en el nodo pasivo, pudiéndose calcular la posición de los nodos activos y la del nodo pasivo de forma conjunta en éste último. El procedimiento está basado en "Sistema y procedimiento de localización basados en medidas pasivas de diferencias temporales tomadas a partir de escuchas de tiempo de llegada de otros nodos", donde se transforman las medidas de tiempo con las que operan los nodos activos, en diferencias temporales en los nodos pasivos.

  • A new time-based algorithm for positioning mobile terminals in wireless networks

     Martin Escalona, Israel; Barceló Arroyo, Francisco
    Eurasip journal on advances in signal processing
    Date of publication: 2008-05
    Journal article

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  • Premio al mejor artículo ofrecido por la Fundación Vodafone en el marco del congreso JITEL 2008

     Martin Escalona, Israel; Barceló Arroyo, Francisco
    Award or recognition

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  • Impact of geometry on the accuracy of the passive-TDOA algorithm

     Martin Escalona, Israel; Barceló Arroyo, Francisco
    IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC 2008)
    Presentation of work at congresses

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  • Localización pasiva de terminales mediante TDOA en redes de difusión

     Martin Escalona, Israel; Barceló Arroyo, Francisco
    Jornadas de Ingeniería Telemática
    Presentation of work at congresses

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  • On the availability of GNSS and terrestrial location techniques: a field study

     Martin Escalona, Israel; Barceló Arroyo, Francisco; De la fuente, Andres
    IEEE Vehicular Technology Conference
    Presentation of work at congresses

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    Hybridization is a hot topic in the location field. Since there is no universal location technique that is capable of positioning in indoor and outdoor environments, two or more techniques must be coupled to produce a complete location solution. Accordingly, information on the availability of each of the techniques being coupled is of great relevance in the design and implementation stages of the location system. In public cellular networks, this coupling usually involves a terrestrial triangulation technique (e.g. E-OTD, OTDOA) and a GNSSbased technique (e.g. A-GPS). The purpose of this paper is twofold. Firstly, it presents a software tool developed for studying the availability of location systems in certain environments, which is able to capture and present information on the availability of satellites in the NAVSTAR constellation (i.e. GPS) and the GSM/GPRS base stations being received in the user terminal. Secondly, it studies the coverage of these techniques using the tool described. Availability data for three routes in an urban environment are gathered and analyzed. In two of them, GPS did not cover 100% of the route, which demonstrated the need to couple the technique with another terrestrial technique to cope with the “dark” areas.