IMDEA Networks Institute Digital Repository
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1915 research outputs found
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NEMO-Enabled Localized Mobility Support for Internet Access in Automotive Scenarios
Get PDFThis article surveys the major existing approaches and proposes a novel architecture to support mobile networks in network-based, localized mobility domains. Our architecture
enables conventional terminals without mobility support to obtain connectivity either from fixed locations or mobile platforms (e.g., vehicles) and move between them, while keeping their ongoing sessions. This functionality offers
broadband Internet access in automotive scenarios such as public transportation systems, where users spend time both in vehicles and at stations. The key advantage of our proposal, as compared with current alternatives, is that the
described mobile functionality is provided to conventional IP devices that lack mobility functionality. We also performed an experimental evaluation of our proposal that shows that our architecture improves the quality perceived by the end users.TRUEpu
Supporting Carrier Grade Services Over Wireless Mesh Networks: The Approach of the European FP-7 STREP CARMEN
Get PDFCARMEN is a three-year Specific Targeted Research Project (STREP) funded by the European Commission within the 7th Framework Program. The CARMEN access network will complement existing access technologies by exploiting low cost mesh networking techniques, thus minimizing deployment and maintenance costs. The CARMEN architecture introduces an abstraction layer that hides the specifics of the underlying access technology providing an abstract interface on top of which higher layers can be easily developed. This allows for the integration of current and future heterogeneous wireless technologies to provide scalable and efficient mobile ubiquitous Internet access, able to adapt to different environments and user requirements. Following these goals, CARMEN aims to define, study and implement link and technology abstractions, mobility support, and quality of service. The architecture also includes advanced monitoring features that allow for dynamic self-configuration, thereby reducing the installation and operational costs.TRUEpu
Perceptibility of DigitalWatermarks Embedded in 3D Meshes using Unimodal and Bimodal Hapto-Visual Interaction
Get PDFIn this paper, a study is conducted in order to measure
and analyze the perceptibility of watermarks embedded in 3D meshes when (1) visual feedback is present, (2) haptic feedback is present, and (3) visual and haptic feedback are simultaneously available. More specifically, our experiments are intended to assess whether the use of a bimodal approach, where a subject is looking at, and touching a 3D mesh could in fact improve the perceptibility of a watermark as opposed to when only a single modality is available. The experiments are performed using a hapto-visual interface which integrates a haptic device with stereo graphics for an immersive high quality 3D experience. Overall, the results suggested that relying on bimodal hapto-visual feedback is better than any of the single modalities when detecting a watermark embedded in a 3D model. Further experiments with a greater number of subjects would however be necessary to bet-
ter confirm this conclusionTRUEpu
Throughput and Energy Efficiency in IEEE 802.11 WLANs: Friends or Foes?
Get PDFUnderstanding and optimizing the energy consumption of
wireless devices is critical to maximize network lifetime and to provide guidelines for the design of new protocols and interfaces. In this work we first provide an accurate analysis of the energy performance of an IEEE 802.11 WLAN, and then we derive the configuration to maximize it. We also analyze the impact of the energy configuration of the device on the throughput performance, and discuss in which circumstances throughput and energy efficiency can be both maximized and where they constitute different challenges.TRUEpu
Benefits on using H-P2PSIP in mobile environments
Get PDFThis research work is being supported by the European Commission under the IST Content Network of Excellence3 (FP6-2006-IST-038423), by the Regional Government of Madrid under the BioGridNet4 project (CAM, S-0505/TIC- 0101) and by the Ministry of Science and Innovation under the CONPARTE project (MEC, TEC2007-67966-C03-03/TCM).The use of peer-to-peer technologies is increasing everyday and the improvement of mobility technologies is a reality. Now, it is expected that peer-to-peer applications run on mobile devices, but the conjunction of these two technologies is an open research issue. The user mobility impacts on the churn suffered by peer-to-peer networks and consequently it impacts on their performance. Therefore, some mechanisms are necessary to minimize this undesirable effect. Our proposal tries to solve this problem by using a Hierarchical P2PSIP architecture where different overlays are used for different peer mobility behaviours and they are interconnected between them through an interconnection overlay. In this way it is possible for peers that share the same behaviour to choose a certain protocol or to optimize some functionality that suits best with their mobility situation, while maintaining connectivity with all peers.TRUEpu
Energy-Efficient Management of UMTS Access Networks
Get PDFThe increasing concern about the energy consumption
of telecommunication networks is driving operators to
manage their equipments so as to optimize energy utilization
without sacrificing the user experience. In this paper, we focus on UMTS access networks, since access devices are the main energy consumers in UMTS networks. We propose a novel approach for the energy-aware management of UMTS access networks, consisting in a dynamic network planning, that, based on the instantaneous traffic intensity, reduces the number of active access devices when they are underutilized (typically at night).
When some access devices are switched off, radio coverage and service provisioning are taken care of by the devices that remain active, possibly with some small increase in the emitted power, so as to guarantee that service is available over the whole area, with the desired quality.TRUEpu
Experiences with a flexible QoS capable residential Gateway within a multiservice Framework
Get PDFIt is sometimes believed that a “broadband access” network,
providing ample transmission capacity to residential environments, is enough so as to allow a flawless delivery of advanced services. However, the provisioning of a combination of multiple services with guaranteed quality up to the end-user terminal requires a carefully designed architecture incorporating the appropriated Quality of Service (QoS) concepts throughout the data path. And this path includes the Residential Gateway (RGW) as the last hop towards the home network. This paper describes the architecture of a RGW prototype designed and implemented within the framework of the European IST research
project MUSE. The paper also addresses the different experiences performed with the prototype. Special emphasis will be made on the QoS capabilities of the RGW as well as on authentication and auto-configuration features.TRUEpu
Plataforma Genérica para la Provisión de Servicios en Redes con Plano de Control IMS
No full textExiste una tendencia hacia la convergencia entre los
distintos dominios de redes de comunicación denominada Convergencia Fijo-Móvil, que promulga la consolidación de una red única en la cual sea posible la provisión de servicios a los que hasta ahora se ha accedido mediante distintos mecanismos de control. El presente artículo se centra en el diseño y desarrollo de una plataforma genérica para la provisión de servicios en redes con plano de control IMS (Subsistema Multimedia IP). Esta consistirá en un Sistema Cliente, capaz de realizar cualquier descripción de sesión e iniciar el establecimiento de dicha sesión y en un Sistema Servidor que proporcionará una interfaz genérica sobre la que será
posible implementar servicios multimedia de valor añadido.
Adicionalmente, se validará la solución presentada,
mediante la implementación de un servidor de Video bajo Demanda.TRUEpu
Segmentación Geográfica en los Servicios de Telecomunicaciones: Aspectos Económicos y Tecnológicos
Get PDFLa Comisión Europea y los reguladores nacionales están planteando la posibilidad de segmentar geográficamente mercados que tradicionalmente se han considerado de ámbito nacional. Atendiendo al caso británico, donde la segmentación geográfica ha dado lugar a la supresión de las obligaciones regulatorias que pesaban sobre el operador incumbente en determinadas zonas, esta medida puede considerarse un paso adelante en el proceso de progresiva liberalización y apertura hacia la competencia de las telecomunicaciones. En este artículo, revisamos los principales estudios que han analizado la relación entre regulación y bienestar e inversión con el objeto de arrojar algo de luz sobre el posible impacto de la segmentación geográfica como instrumento para reducir el
alcance de la regulación en el sector de las telecomunicaciones. Este análisis resulta de especial relevancia en el momento actual para el sector español, en el que la CMT está llevando a cabo su revisión de los mercados y los operadores están decidiendo sobre inversiones multimillonarias en despliegue de redes de acceso de nueva generación.pu