548 research outputs found

    A methodology for obtaining More Realistic Cross-Layer QoS Measurements in mobile networks: A VoIP over LTE Use Case

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    Los servicios de voz han sido durante mucho tiempo la primera fuente de ingresos para los operadores móviles. Incluso con el protagonismo creciente del tráfico de datos, los servicios de voz seguirán jugando un papel importante y no desaparecerán con la transición a redes basadas en el protocolo IP. Por otra parte, hace años que los principales actores en la industria móvil detectaron claramente que los usuarios no aceptarían una degradación en la calidad de los servicios de voz. Es por esto que resulta crítico garantizar la experiencia de usuario (QoE) en la transición a redes de nueva generación basadas en conmutación de paquetes. El trabajo realizado durante esta tesis ha buscado analizar el comportamiento y las dependencias de los diferentes servicios de Voz sobre IP (VoIP), así como identificar configuraciones óptimas, mejoras potenciales y metodologías que permitan asegurar niveles de calidad aceptables al mismo tiempo que se trate de minimizar los costes. La caracterización del rendimiento del tráfico de datos en redes móviles desde el punto de vista de los usuarios finales es un proceso costoso que implica la monitorización y análisis de un amplio rango de protocolos y parámetros con complejas dependencias. Para abordar desde la raíz este problema, se requiere realizar medidas que relacionen y correlen el comportamiento de las diferentes capas. La metodología de caracterización propuesta en esta tesis proporciona la posibilidad de recoger información clave para la resolución de problemas en las comunicaciones IP, relaciolándola con efectos asociados a la propagación radio, como cambios de celda o pérdida de enlaces, o con carga de la red y limitaciones de recursos en zonas geográficas específicas. Dicha metodología se sustenta en la utilización de herramientas nativas de monitorización y registro de información en smartphones, y la aplicación de cadenas de herramientas para la experimentación extensiva tanto en redes reales y como en entornos de prueba controlados. Con los resultados proporcionados por esta serie de herramientas, tanto operadores móviles y proveedores de servicio como desarrolladores móviles podrían ganar acceso a información sobre la experiencia real del usuario y sobre cómo mejorar la cobertura, optimizar los servicios y adaptar el funcionamiento de las aplicaciones y el uso de protocolos móviles basados en IP en este contexto. Las principales contribuciones de las herramientas y métodos introducidos en esta tesis son los siguientes: - Una herramienta de monitorización multicapa para smartphones Android, llamada TestelDroid, que permite la captura de indicadores clave de rendimiento desde el propio equipo de usuario. Asimismo proporciona la capacidad de generar tráfico de forma activa y de verificar el estado de alcanzabilidad del terminal, realizando pruebas de conectividad. - Una metodología de post-procesado para correlar la información presente en las diferentes capas de las medidas realizadas. De igual forma, se proporciona la opción a los usuarios de acceder directamente a la información sobre el tráfico IP y las medidas radio y de aplicar metodologías propias para la obtención de métricas. - Se ha realizado la aplicación de la metodología y de las herramientas usando como caso de uso el estudio y evaluación del rendimiento de las comunicaciones basadas en IP a bordo de trenes de alta velocidad. - Se ha contribuido a la creación de un entorno de prueba realista y altamente configurable para la realización de experimentos avanzados sobre LTE. - Se han detectado posibles sinergias en la utilización de instrumentación avanzada de I+D en el campo de las comunicaciones móviles, tanto para la enseñanza como para la investigación en un entorno universitario

    INTELLIGENTE TRANSPORT SYSTEMEN ITS EN VERKEERSVEILIGHEID

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    This report discusses Intelligent Transport Systems (ITS). This generic term is used for a broad range of information-, control- and electronic technology that can be integrated in the road infrastructure and the vehicles themselves, saving lives, time and money bymonitoring and managing traffic flows, reducing conges-tion, avoiding accidents, etc. Because this report was written in the scope of the Policy Research Centre Mobility & Public Works, track Traffic Safety, it focuses on ITS systems from the traffic safety point of view. Within the whole range of ITS systems, two categories can be distinguished: autonomous and cooperative systems. Autonomous systems are all forms of ITS which operate by itself, and do not depend on the cooperation with other vehicles or supporting infrastructure. Example applications are blind spot detection using radar, electronic stability control, dynamic traffic management using variable road signs, emergency call, etc. Cooperative systems are ITS systems based on communication and cooperation, both between vehicles as between vehicles and infrastructure. Example applications are alerting vehicles approaching a traffic jam, exchanging data regarding hazardous road conditions, extended electronic brake light, etc. In some cases, autonomous systems can evolve to autonomous cooperative systems. ISA (Intelligent Speed Adaptation) is an example of this: the dynamic aspect as well as communication with infrastructure (eg Traffic lights, Variable Message Sign (VMS)...) can provide additional road safety. This is the clear link between the two parts of this report. The many ITS applications are an indicator of the high expectations from the government, the academic world and the industry regarding the possibilities made possible by both categories of ITS systems. Therefore, the comprehensive discussion of both of them is the core of this report. The first part of the report covering the autonomous systems treats two aspects: 1. Overview of European projects related to mobility and in particular to road safety 2. Overview for guidelines for the evaluation of ITS projects. Out of the wide range of diverse (autonomous) ITS applications a selection is made; this selection is focused on E Safety Forum and PreVENT. Especially the PreVent research project is interesting because ITS-applications have led to a number of concrete demonstration vehicles that showed - in protected and unprotected surroundings- that these ITS-applications are already technically useful or could be developed into useful products. The component “guidelines for the evaluation of ITS projects” outlines that the government has to have specific evaluation tools if the government has the ambition of using ITS-applications for road safety. Two projects -guidelines for the evaluation of ITS projects- are examined; a third evaluation method is only mentioned because this description shows that a specific targeting of the government can be desirable : 1. TRACE describes the guidelines for the evaluation of ITS projects which are useful for the evaluation of specific ITS-applications. 2. FITS contains Finnish guidelines for the evaluation of ITS project; FIS is an adaptation of methods used for evaluation of transport projects. 3. The third evaluation method for the evaluation of ITS projects is developed in an ongoing European research project, eImpact. eImpact is important because, a specific consultation of stake holders shows that the social importance of some techniques is underestimated. These preliminary results show that an appropriate guiding role for the government could be important. In the second part of this document the cooperative systems are discussed in depth. These systems enable a large number of applications with an important social relevance, both on the level of the environment, mobility and traffic safety. Cooperative systems make it possible to warn drivers in time to avoid collisions (e.g. when approaching the tail of a traffic jam, or when a ghost driver is detected). Hazardous road conditions can be automatically communicated to other drivers (e.g. after the detection of black ice or an oil trail by the ESP). Navigation systems can receive detailed real-time up-dates about the current traffic situation and can take this into account when calculating their routes. When a traffic distortion occurs, traffic centers can immediately take action and can actively influence the way that the traffic will be diverted. Drivers can be notified well in advance about approaching emergency vehicles, and can be directed to yield way in a uniform manner. This is just a small selection from the large number of applications that are made possible because of cooperative ITS systems, but it is very obvious that these systems can make a significant positive contribution to traffic safety. In literature it is estimated that the decrease of accidents with injuries of fatalities will be between 20% and 50% . It is not suprising that ITS systems receive a lot of attention for the moment. On an international level, a number of standards are being established regarding this topic. The International Telecommunications Uniont (ITU), Institute for Electrical and Electronics Engineers (IEEE), International Organization for Standardization (ISO), Association of Radio Industries and Business (ARIB) and European committee for standardization (CEN) are currently defining standards that describe different aspects of ITS systems. One of the names that is mostly mentioned in literature is the ISO TC204/WG16 Communications Architecture for Land Mobile environment (CALM) standard. It describes a framework that enables transparent (both for the application and the user) continuous communication through different communication media. Besides the innumerable standardization activities, there is a great number of active research projects. On European level, the most important are the i2010 Intelligent Car Initiative, the eSafety Forum, and the COMeSafety, the CVIS, the SAFESPOT, the COOPERS and the SEVECOM project. The i2010 Intelligent Car Initiative is an European initiative with the goal to halve the number of traffic casualties by 2010. The eSafety Forum is an initiative of the European Commission, industry and other stakeholders and targets the acceleration of development and deployment of safety-related ITS systems. The COMeSafety project supports the eSafety Forum on the field of vehicle-to-vehicle and vehicle-to-infrastructure communication. In the CVIS project, attention is given to both technical and non-technical issues, with the main goal to develop the first free and open reference implementation of the CALM architecture. The SAFEST project investigates which data is important for safety applications, and with which algorithmsthis data can be extracted from vehicles and infrastructure. The COOPERS project mainly targets communication between vehicles and dedicated roadside infrastructure. Finally, the SEVECOM project researches security and privacy issues. Besides the European projects, research is also conducted in the United States of America (CICAS and VII projects) and in Japan (AHSRA, VICS, Smartway, internetITS). Besides standardization bodies and governmental organizations, also the industry has a considerable interest in ITS systems. In the scope of their ITS activities, a number of companies are united in national and international organizations. On an international level, the best known names are the Car 2 Car Communication Consortium, and Ertico. The C2C CC unites the large European car manufacturers, and focuses on the development of an open standard for vehicle-to-vehicle and vehicle-to-infrastructure communications based on the already well established IEEE 802.11 WLAN standard. Ertico is an European multi-sector, public/private partnership with the intended purpose of the development and introduction of ITS systems. On a national level, FlandersDrive and The Telematics Cluster / ITS Belgium are the best known organizations. Despite the worldwide activities regarding (cooperative) ITS systems, there still is no consensus about the wireless technology to be used in such systems. This can be put down to the fact that a large number of suitable technologies exist or are under development. Each technology has its specific advantages and disadvantages, but no single technology is the ideal solution for every ITS application. However, the different candidates can be classified in three distinct categories. The first group contains solutions for Dedicated Short Range Communication (DSRC), such as the WAVE technology. The second group is made up of several cellular communication networks providing coverage over wide areas. Examples are GPRS (data communication using the GSM network), UMTS (faster then GPRS), WiMAX (even faster then UMTS) and MBWA (similar to WiMAX). The third group consists of digital data broadcast technologies such as RDS (via the current FM radio transmissions, slow), DAB and DMB (via current digital radio transmissions, quicker) and DVB-H (via future digital television transmissions for mobiledevices, quickest). The previous makes it clear that ITS systems are a hot topic right now, and they receive a lot of attention from the academic world, the standardization bodies and the industry. Therefore, it seems like that it is just a matter of time before ITS systems will find their way into the daily live. Due to the large number of suitable technologies for the implementation of cooperative ITS systems, it is very hard to define which role the government has to play in these developments, and which are the next steps to take. These issues were addressed in reports produced by the i2010 Intelligent Car Initiative and the CVIS project. Their state of the art overview revealed that until now, no country has successfully deployed a fully operational ITS system yet. Seven EU countries are the furthest and are already in the deployment phase: Sweden, Germany, the Netherlands, the United Kingdom, Finland, Spain and France. These countries are trailed by eight countries which are in the promotion phase: Denmark, Greece, Italy, Austria, Belgium,Norway, the Czech Republic and Poland. Finally, the last ten countries find themselves in the start-up phase: Estonia, Lithuania, Latvia, Slovenia, Slovakia, Hungary, Portugal, Switzerland, Ireland and Luxembourg. These European reports produced by the i2010 Intelligent Car Initiative and the CVIS project have defined a few policy recommendations which are very relevant for the Belgian and Flemish government. The most important recommendations for the Flemish government are: • Support awareness: research revealed that civilians consider ITS applications useful, but they are not really willing to pay for this technology. Therefore, it is important to convince the general public of the usefulness and the importance of ITS systems. • Fill the gaps: Belgium is situated in the promotion phase. This means that it should focus at identifying the missing stakeholders, and coordinating national and regional ITS activities. Here it is important that the research activities are coordinated in a national and international context to allow transfer of knowledge from one study to the next, as well as the results to be comparable. • Develop a vision: in the scope of ITS systems policies have to be defined regarding a large number of issues. For instance there is the question if ITS users should be educated, meaning that the use of ITS systems should be the subject of the drivers license exam. How will the regulations be for the technical inspection of vehicles equipped with ITS technology? Will ITS systems be deployed on a voluntary base, or will they e.g. be obliged in every new car? Will the services be offered by private companies, by the public authorities, or by a combination of them? Which technology will be used to implement ITS systems? These are just a few of the many questions where the government will have to develop a point of view for. • Policy coordination: ITS systems are a policy subject on an international, national and regional level. It is very important that these policy organizations can collaborate in a coordinated manner. • Iterative approach to policy development: developing policies for this complex matter is not a simple task. This asks for an iterative approach, where policy decisions are continuously refined and adjusted

    Chaotic assessment of the key performance indicators for a GSM Network congestion in an election period in Nigeria

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    This paper investigates the chaos-based assessment of the Key performance Indicators (KPIs) for the Cellular network congestion during and after 2011 People Democratic Party (PDP) presidential primary election in Eagle Square within Abuja and its environs. Chaotic quantifiers such as average mutual information, Lyapunov exponents and specific attenuation were employed to study the congestion rate or dynamical state of the network. The chaotic assessment of the Wideband Code Division Multiplexing Access (WCDMA) data services provided by MTN network using KPIs are reported. The data retrieved from the three Base Transceiver Stations (BTSs) were used to analyse the performance of the network. The results revealed the state of dynamical behaviour of the congestion during the study period. Keywords: Key performance Indicators (KPIs); Wideband Code Division Multiplexing Access (WCDMA); Global System of Mobile communication (GSM); Base Transceiver Station (BTS); Chaotic Quantifier

    Mobiilin Internetin käytön mittaukset Suomessa

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    Mobile Internet is the outcome of two intense and global trends of the recent years: mobile/wireless and the Internet. Despite the potential the hundreds of millions of new mobile devices sold globally each year present, little information on mobile data service usage apart from mobile operator portals is currently available. In this research, mobile Internet usage was measured in fall 2005 using three fundamentally different methods to answer the question What are the characteristics of consumer mobile Internet usage in Finland? First, data on 80-90% of all Finnish mobile subscribers and terminals was collected with mobile operators' charging-oriented reporting systems. The observed Finnish mobile terminal installed base was old and did not widely support key features for data usage as e.g. packet data capability was in 48% and WCDMA capability in less than 1% of terminals. Nokia's market share was a remarkable 87%. Smartphones constituted 6% of all terminals, over 99% of which were Nokia's Symbian handsets and one third of these Nokia communicators. The terminal base was fairly concentrated as the 50 most common models made up 88% of all terminals. Some 92-94% of all mobile subscribers were postpaid subscribers, 75% of them consumers. While 99% of consumers had operators' default usage-based packet data tariff plan, the remaining 1% created 82% of all consumer subscriber packet data traffic. Second, 50% of all Finnish mobile network packet data traffic was captured in TCP/IP header collection -based measurements. Strikingly, the Windows operating system originated 65% of all packet data traffic in mobile networks. Moreover, VPN usage created 46% of traffic volume leading to a very high 85% share of UDP traffic. The Internet APN accounted for 90% of all packet data traffic. Third, a panel of 500 Finnish Symbian S60 handsets was monitored with software installed in the handsets. Panelists with higher radio capability handsets used packet data more frequently and in higher volumes. Data usage volumes were also higher for users with relatively cheaper fixed fee packet data plans. Operator sites and infotainment dominated web/wap site visits with 32% and 33% shares of all visits. Using handset as a modem formed a 21-25% part of all smartphone data traffic. The most active 20% of data users created 80% of traffic, even when modem traffic was excluded. Browsing was the most important data application area with a 72% share of non-modem traffic, and its relative share increased with data usage volume. In conclusion, Finnish mobile data usage is currently business driven. Traffic to non-operator controlled sites appears to be important. The usage of 3G terminals and effectively flat-rate packet data tariffs seems to increase data usage considerably, and browser is a central application also in mobiles. Mobile operators are recommended to include items on off portal traffic to their regular reporting. Similar measurements enabling evaluation of the development of Finnish mobile data usage should be repeated. The measurement methods could also be productized or sold to operators as a service by a 3rd party. Potential ways to utilize the handset-based data are numerous.Mobiili Internet on seurausta kahden viimeaikaisen voimakkaan ja globaalin trendin, liikkuvuuden ja Internetin yhdistymisestä. Huolimatta satojen miljoonien vuosittain globaalisti myytyjen mobiililaitteiden edustamasta potentiaalista, operaattoreiden portaalien ulkopuolista mobiilien datapalveluiden käyttöä ei tunneta hyvin. Tässä tutkimuksessa mitattiin mobiilin Internetin käyttöä syksyllä 2005 käyttäen kolmea erilaista menetelmää vastattaessa kysymykseen Mitkä ovat mobiilin Internetin kuluttajakäytön ominaispiirteet Suomessa? Ensimmäiseksi, mobiilioperaattoreiden laskutukseen perustuvien raportointijärjestelmien avulla kerättiin aineistoa 80-90% Suomen mobiilitilaajista ja -päätelaitteista. Suomen päätelaitekanta havaittiin vanhaksi ja datakäytölle keskeiset ominaisuudet rajallisesti levinneiksi, sillä pakettidatakyvykkyys oli 48% ja WCDMA kyvykkyys vain 1% päätelaitteista. Nokian markkinaosuus oli huomattava 87%. Kaikista päätelaitteista älypuhelimia oli 6%, joista 99% oli Nokian Symbian puhelimia ja näistä kolmannes Nokian kommunikaattoreita. Päätelaitekanta oli varsin keskittynyt 50 yleisimmän mallin vastatessa 88% kaikista päätelaitteista. Mobiilitilaajista 92-94% oli postpaid-tilaajia, 75% heistä kuluttajia. Vaikka 99% kuluttajista oli oletusarvoisen käyttöperusteisen pakettidatahinnoittelun piirissä, loput 1% loi 82% kuluttajatilaajien pakettidataliikenteestä. Toiseksi, 50% suomalaisten mobiiliverkkojen pakettidataliikenteestä mitattiin keräämällä TCP/IP otsakkeita. Silmäänpistävin tulos oli Windows-käyttöjärjestelmän 65% osuus kaikesta pakettidataliikenteestä. VPN-käyttö loi 46% liikennevolyymistä johtaen UDP-liikenteen hyvin korkeaan 85% osuuteen. Internet APN vastasi 90% kaikesta pakettidataliikenteestä. Kolmanneksi, 500 suomalaisen Symbian S60 puhelimen paneelia monitoroitiin puhelimiin asennetulla sovelluksella. Radioltaan kyvykkäämpiä puhelinten käyttäjät käyttivät pakettidataa useammin ja enemmän. Datakäytön volyymit olivat korkeampia suhteellisesti halvemman kiinteän hinnoittelun käyttäjillä. Operaattoreiden sivustot ja tietoviihde hallitsisivat web/wap käyttöä 32% ja 33% osuuksilla kaikista vierailuista. Modeemikäyttö muodosti 21-25% osuuden kaikesta älypuhelinten dataliikenteestä. Aktiivisin 20% datakäyttäjistä loi 80% liikenteestä, myös kun modeemikäyttöä ei huomioitu. Selainkäyttö oli tärkein datasovellusalue 72% osuudella ei-modeemiliikenteestä, sen suhteellinen osuus kasvoi datakäytön volyymin myötä. Suomalainen mobiilidatakäyttö on tällä hetkellä yrityskäyttäjävetoista. Operaattoreiden portaalien ulkopuolinen liikenne vaikuttaa tärkeältä. Kolmannen sukupolven päätelaitteiden ja kiinteän hinnoittelun käyttö näyttää kasvattavan datakäyttöä merkittävästi, ja selain on keskeinen sovellus myös mobiilissa. Mobiilioperaattoreiden tulisi liittää portaaliliikenteen ulkopuolinen käyttö sisäiseen raportointiinsa. Vastaavat mittaukset tulisi toistaa mobiilidatakäytön kehittymisen arvioimiseksi. Käytettyjen mittausmenetelmien tuotteistaminen tai myynti palveluna operaattoreille kolmannen osapuolen toimesta on mahdollista. Päätelaitepohjaisella aineistolla on lukuisia käyttökohteita

    Ray Launching Modeling in Curved Tunnels with Rectangular or Non Rectangular Section

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    International audienceSeveral methods to model radio wave propagation in tunnels have been published in the literature and will be presented in this chapter with their advantages and drawbacks. Among them, only few works are dedicated to non rectangular cross section and curved tunnels. Hence, we focus on a new method recently developed. The structure of the chapter is as follows. Section 2 presents the context of the works and why deployments of wireless telecommunication systems are needed for transport applications. Existing techniques to model radio wave propagation in tunnel are presented in section 3 with their respective advantages and drawbacks. The fourth and fifth sections are respectively devoted to the design and the evaluation of a propagation prediction model for curved tunnel with a rectangular or a circular cross section. Finally, section 6 concludes and presents some perspectives to these works

    Quadri-dimensional approach for data analytics in mobile networks

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    The telecommunication market is growing at a very fast pace with the evolution of new technologies to support high speed throughput and the availability of a wide range of services and applications in the mobile networks. This has led to a need for communication service providers (CSPs) to shift their focus from network elements monitoring towards services monitoring and subscribers’ satisfaction by introducing the service quality management (SQM) and the customer experience management (CEM) that require fast responses to reduce the time to find and solve network problems, to ensure efficiency and proactive maintenance, to improve the quality of service (QoS) and the quality of experience (QoE) of the subscribers. While both the SQM and the CEM demand multiple information from different interfaces, managing multiple data sources adds an extra layer of complexity with the collection of data. While several studies and researches have been conducted for data analytics in mobile networks, most of them did not consider analytics based on the four dimensions involved in the mobile networks environment which are the subscriber, the handset, the service and the network element with multiple interface correlation. The main objective of this research was to develop mobile network analytics models applied to the 3G packet-switched domain by analysing data from the radio network with the Iub interface and the core network with the Gn interface to provide a fast root cause analysis (RCA) approach considering the four dimensions involved in the mobile networks. This was achieved by using the latest computer engineering advancements which are Big Data platforms and data mining techniques through machine learning algorithms.Electrical and Mining EngineeringM. Tech. (Electrical Engineering
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