242 resultados para TDD-LTE


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Long Term Evolution (LTE) represents the fourth generation (4G) technology which is capable of providing high data rates as well as support of high speed mobility. The EU FP7 Mobile Cloud Networking (MCN) project integrates the use of cloud computing concepts in LTE mobile networks in order to increase LTE's performance. In this way a shared distributed virtualized LTE mobile network is built that can optimize the utilization of virtualized computing, storage and network resources and minimize communication delays. Two important features that can be used in such a virtualized system to improve its performance are the user mobility and bandwidth prediction. This paper introduces the architecture and challenges that are associated with user mobility and bandwidth prediction approaches in virtualized LTE systems.

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With the current growth of mobile devices usage, mobile net- works struggle to deliver content with an acceptable Quality of Experience. In this paper, we propose the integration of Information Centric Networking into 3GPP Long Term Evolution mobile networks, allowing its inherent caching feature to be explored in close proximity to the end users by deploying components inside the evolved Node B. Apart from the advantages brought by Information-Centric Networking’s content requesting paradigm, its inherent caching features enable lower latencies to access content and reduce traffic at the core network. Results show that the impact on the evolved Node B performance is low and ad- vantages coming from Information-Centric Networking are considerable. Thus, mobile network operators reduce operational costs and users end up with a higher perceived network quality even in peak utilization periods.

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Mobile networks usage rapidly increased over the years, with great consequences in terms of performance requirements. In this paper, we propose mechanisms to use Information-Centric Networking to perform load balancing in mobile networks, providing content delivery over multiple radio technologies at the same time and thus efficiently using resources and improving the overall performance of content transfer. Meaningful results were obtained by comparing content transfer over single radio links with typical strategies to content transfer over multiple radio links with Information-Centric Networking load balancing. Results demonstrate that Information-Centric Networking load balancing increases the performance and efficiency of 3GPP Long Term Evolution mobile networks while greatly improving the network perceived quality for end users.

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Cloudification of the Centralized-Radio Access Network (C-RAN) in which signal processing runs on general purpose processors inside virtual machines has lately received significant attention. Due to short deadlines in the LTE Frequency Division Duplex access method, processing time fluctuations introduced by the virtualization process have a deep impact on C-RAN performance. This paper evaluates bottlenecks of the OpenAirInterface (OAI is an open-source software-based implementation of LTE) cloud performance, provides feasibility studies on C-RAN execution, and introduces a cloud architecture that significantly reduces the encountered execution problems. In typical cloud environments, the OAI processing time deadlines cannot be guaranteed. Our proposed cloud architecture shows good characteristics for the OAI cloud execution. As an example, in our setup more than 99.5% processed LTE subframes reach reasonable processing deadlines close to performance of a dedicated machine.

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Recently telecommunication industry benefits from infrastructure sharing, one of the most fundamental enablers of cloud computing, leading to emergence of the Mobile Virtual Network Operator (MVNO) concept. The most momentous intents by this approach are the support of on-demand provisioning and elasticity of virtualized mobile network components, based on data traffic load. To realize it, during operation and management procedures, the virtualized services need be triggered in order to scale-up/down or scale-out/in an instance. In this paper we propose an architecture called MOBaaS (Mobility and Bandwidth Availability Prediction as a Service), comprising two algorithms in order to predict user(s) mobility and network link bandwidth availability, that can be implemented in cloud based mobile network structure and can be used as a support service by any other virtualized mobile network services. MOBaaS can provide prediction information in order to generate required triggers for on-demand deploying, provisioning, disposing of virtualized network components. This information can be used for self-adaptation procedures and optimal network function configuration during run-time operation, as well. Through the preliminary experiments with the prototype implementation on the OpenStack platform, we evaluated and confirmed the feasibility and the effectiveness of the prediction algorithms and the proposed architecture.

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Location prediction has attracted a significant amount of research effort. Being able to predict users’ movement benefits a wide range of communication systems, including location-based service/applications, mobile access control, mobile QoS provision, and resource management for mobile computation and storage management. In this demo, we present MOBaaS, which is a cloudified Mobility and Bandwidth prediction services that can be instantiated, deployed, and disposed on-demand. Mobility prediction of MOBaaS provides location predictions of a single/group user equipments (UEs) in a future moment. This information can be used for self-adaptation procedures and optimal network function configuration during run-time operations. We demonstrate an example of real-time mobility prediction service deployment running on OpenStack platform, and the potential benefits it bring to other invoking services.

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With a boom in the usage of mobile devices for traffic-heavy applications, mobile networks struggle to deliver good performance while saving resources to support more users and save on costs. In this paper, we propose enhanced strategies for the preemptive migration of content stored in Information-Centric Networking caches at the edge of LTE mobile networks. With such strategies, the concept of content following the users interested in it becomes a reality and content within caches is more optimized towards the requests of nearby users. Results show that the strategies are feasible, efficient and, when compared to default caching strategies, ensure that content is delivered faster to end users while using bandwidth and storage resources more efficiently at the core of the network.

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The accurate computation of radioactive opacities is needed in several research fields such as astrophysics, magnetic fusion or ICF target physics analysis, in which the radiation transport is an important feature to determine in detail. Radiation transport plays an important role in the transport of energy in dense plasma and it is strongly influenced by the variation of plasma opacity with density and temperature, as well as, photon energy. In this work we present some new features of the opacity code ATMED [1]. This code has been designed to compute the spectral radioactive opacity as well as the Rosseland and Planck means for single element and mixture plasmas. The model presented is fast, stable and reasonably accurate into its range of application and it can be a useful tool to simulate ICF experiments in plasma laboratory.

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Este Proyecto Investigador se presenta como parte de la documentación requerida para el Concurso de Acceso a plazas de cuerpos docentes universitarios. Centro: E.T.S.I. de Telecomunicación. Cuerpo: Profesores Titulares de Universidad. Departamento: Señales, Sistemas y Radiocomunicaciones (0935). Área de conocimiento: Teoría de la Señal y Comunicaciones (800). Perfil docente: Radiocomunicaciones; Comunicaciones Móviles. Perfil investigador: Tecnología de las Telecomunicaciones (3325). Dedicación: Completa

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Este proyecto, recoge el estudio de diferentes simuladores sobre comunicaciones móviles, que se encargan de analizar el comportamiento de las tecnologías UMTS (Universal Mobile Telecommunications System), 3G y LTE (Long Term Evolution),3.9G, centrándose principalmente en el caso de los simuladores LTE, ya que es la tecnología que se está implantando en la actualidad. Por ello, antes de analizar las características de la interfaz radio más importante de esta generación, la 3.9G, se hará una overview general de cómo han ido evolucionando las comunicaciones móviles a lo largo de la historia, se analizarán las características de la tecnología móvil actual, la 3.9G, para posteriormente centrarse en un par de simuladores que demostrarán, mediante resultados gráficos, estas características. Hoy en día, el uso de estos simuladores es totalmente necesario, ya que las comunicaciones móviles, avanzan a un ritmo vertiginoso y es necesario por lo tanto conocer las prestaciones que pueden producir las diferentes tecnologías móviles utilizadas. Los simuladores utilizados por este proyecto, permiten analizar el comportamiento de varios escenarios, ya que existen diferentes tipos de simuladores, tanto a nivel de enlace como a nivel de sistema. Se mencionarán una serie de simuladores correspondientes a la tercera generación UMTS, pero los simuladores en cuestión que se estudiarán y analizarán con más profundidad en este proyecto fin de carrera son los simuladores “Link-Level” y “System-Level”, desarrollados por el “Institute of Communications and Radio-Frecuency Engineering” de la Universidad de Viena. Estos simuladores permiten realizar diferentes simulaciones, como analizar el comportamiento entre una estación base y un único usuario, para el caso de los simuladores a nivel de enlace, o bien analizar el comportamiento de toda una red en el caso de los simuladores a nivel de sistema. Con los resultados que se pueden obtener de ambos simuladores, se realizarán una serie de preguntas, basadas en la práctica realizada por el profesor de la universidad Politécnica de Madrid, Pedro García del Pino, tanto de tipo teóricas como de tipo prácticas, para comprobar que se han entendido los simuladores analizados. Finalmente se citarán las conclusiones que se obtiene de este proyecto, así como las líneas futuras de acción. PROJECT ABSTRACT This project includes the study of different simulators on mobile communications, which are responsible for analyzing the behavior of UMTS (Universal Mobile Telecommunications System), 3G and LTE (Long Term Evolution), 3.9G, mainly focusing on the case of LTE simulators because it is the technology that is being implemented today. Therefore, before analyzing the characteristics of the most important radio interface of this generation, 3.9G, there will give a general overview how the mobile communications have evolved throughout history, analyzing the characteristics of current mobile technology, the 3.9G, later focus on a pair of simulators that demonstrate through graphical results, these characteristics. Today, the use of these simulators is absolutely necessary, because mobile communications advance at a high rate, and it is necessary to know the features that can produce different mobile technologies that are used. The simulators used for this project, allow to analyze the behavior of several scenarios, as there are different types of simulators, both link and system level. It mentioned a number of simulators for the third generation UMTS, but the simulators in question to be studied and analyzed in this final project are the simulators "Link-Level" and "System-Level", developed by the "Institute of Communications and Radio-Frequency Engineering" at the University of Vienna. These simulators allow realize different simulations, analyze the behavior between a base station and a single user, in the case of the link-level simulators or analyze the performance of a network in the case of system-level simulators. With the results that can be obtained from both simulators, will perform a series of questions, based on the practice developed by Pedro García del Pino, Professor of “Universidad Politécnica de Madrid (UPM)”. These questions will be both of a theoretical and practical type, to check that have been understood the analyzed simulators. Finally, it quotes the conclusions obtained from this project and mention the future lines of action.

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En este proyecto realizaremos un estudio del efecto de las interferencias procedentes de las redes públicas y veremos cómo afectan el rendimiento de las comunicaciones GSM-R que están en la banda de frecuencias adyacente, por un lado, definiremos las características de las redes públicas y como afectan los niveles de potencia y los anchos de banda de redes de banda ancha, especialmente LTE que dispone de un ancho de banda adaptativo que puede llegar hasta 20 MHZ, y por otro lado definiremos las características y las exigencias de las comunicaciones GSM-R que es una red privada que se utiliza actualmente para comunicaciones ferroviales. Con el objetivo de determinar el origen y los motivos de estas interferencias vamos a explicar cómo se produzcan las emisiones no deseadas de las redes públicas que son fruto de la intermodulación que se produzca por las características no lineales de los amplificadores, entre las emisiones no deseadas se puede diferenciar entre el dominio de los espurios y el dominio de las emisiones fuera de banda, para determinar el nivel de las emisiones fuera de banda definiremos la relación de fugas del canal adyacente, ACLR, que determina la diferencia entre el pico de la señal deseada y el nivel de señal interferente en la banda de paso. Veremos cómo afectan estas emisiones no deseadas a las comunicaciones GSMR en el caso de interferencias procedentes de señales de banda estrecha, como es el caso de GSM, y como afectan en el caso de emisiones de banda ancha con los protocolos UMTS y LTE, también estudiaremos como varia el rendimiento de la comunicación GSM-R frente a señales LTE de diferentes anchos de banda. Para reducir el impacto de las interferencias sobre los receptores GSM-R, analizaremos el efecto de los filtros de entrada de los receptores GSM-R y veremos cómo varia la BER y la ACLR. Además, con el objetivo de evaluar el rendimiento del receptor GSM-R ante diferentes tipos de interferencias, simularemos dos escenarios donde la red GSM-R se verá afectada por las interferencias procedente de una estación base de red pública, en el primer escenario la distancia entre la BS y MS GSM-R será de 4.6 KM, mientras en el segundo escenario simularemos una situación típica cuando un tren está a una distancia corta (25 m) de la BS de red pública. Finalmente presentaremos los resultados en forma de graficas de BER y ACLR, y tablas indicando los diferentes niveles de interferencias y la diferencia entre la potencia a la que obtenemos un valor óptimo de BER, 10-3, sin interferencia y la potencia a la que obtenemos el mismo valor con interferencias. ABSTRACT In this project we will study the interference effect from public networks and how they affect the performance of GSM-R communications that are in the adjacent frequency band, furthermore, we will define the characteristics of public networks and will explain how the power levels and bandwidth broadband networks are affected as a result, especially LTE with adaptive bandwidth that can reach 20 MHZ. Lastly, we will define the characteristics and requirements of the GSM-R communications, a private network that is currently used for railways communications. In order to determine the origin and motives of these interferences, we will explain what causes unwanted emissions of public networks that occur as a result. The intermodulation, which is caused by the nonlinear characteristics of amplifiers. Unwanted emissions from the transmitter are divided into OOB (out-of-band) emission and spurious emissions. The OOB emissions are defined by an Adjacent Channel Leakage Ratio (ACLR) requirement. We'll analyze the effect of the OOB emission on the GSM-R communication in the case of interference from narrowband signals such as GSM, and how they affect emissions in the case of broadband such as UMTS and LTE; also we will study how performance varies with GSM-R versus LTE signals of different bandwidths. To reduce the impact of interference on the GSM-R receiver, we analyze the effect of input filters GSM-R receivers to see how it affects the BER (Bits Error Rate) and ACLR. To analyze the GSM-R receiver performance in this project, we will simulate two scenarios when the GSM-R will be affected by interference from a base station (BS). In the first case the distance between the public network BS and MS GSM-R is 4.6 KM, while the second case simulates a typical situation when a train is within a short distance, 25 m, of a public network BS. Finally, we will present the results as BER and ACLR graphs, and tables showing different levels of interference and the differences between the power to obtain an optimal value of BER, 10-3, without interference, and the power that gets the same value with interference.

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En este proyecto se estudiarán las interferencias en el canal adyacente de los sistemas celulares, ubicados en las bandas de 900 y 1800 MHz. Para esto, se analizarán medidas de interferencia entre LTE y otros sistemas de comunicación celular. En el primer capítulo, se dará una breve descripción de los principales parámetros empleados en los distintos estándares de comunicaciones móviles, que operan en las bandas de frecuencia de interés. En el segundo, se van a explicar los distintos tipos de interferencias existentes entre sistemas celulares. También se verán las diferentes técnicas para reducir dichas interferencias, como por ejemplo, la de control de potencia y la de coordinación de interferencia entre celdas. Además, se explicarán los parámetros para determinar la interferencia en el canal adyacente, como son el ACLR, ACS y ACIR. Para finalizar se resumirán las principales características de los sistemas LTE y WiMAX. En el tercer capítulo, se estudiarán las interferencias que genera principalmente LTE a los otros sistemas celulares, mediante los parámetros que miden la interferencia en el canal adyacente explicados en el capítulo dos. Además, se determinará la separación en frecuencia que debe existir entre los canales para que los sistemas puedan coexistir. El capítulo cuatro se basa en la simulación de tres escenarios de interferencia entre dichos sistemas. Para esto, se utilizará el software de simulación de propagación radio, denominado Radio Plan. Con estas simulaciones se cuantificarán las pérdidas de rendimiento que sufren los sistemas interferidos. Por último, en el capítulo cinco se resumirán las conclusiones a las que se llegaron después de simular los diferentes escenarios de interferencia. SUMMARY In this project an adjacent channel interference study for cellular systems, allocated within 900 MHz and 1800 MHz bands will be performed. For this aim a set of measurements will be analyzed. In the first chapter, a brief explanation of the main parameters used in different mobile communications standards that operate in the frequency bands of interest, will be given. In the second chapter, different types of interference between cellular systems will be explained, as well as different techniques to reduce such interference. For example, power control and interference coordination between cells, will be shown. Furthermore, the parameters to determine the adjacent-channel interference, such as the ACLR, ACS and ACIR will be overviewed. Finally, the main features of LTE and WiMAX systems will be summarized. In the third chapter, the interference generated by the other mainly LTE cellular systems via parameters that measure the adjacent channel interference explained in chapter two will be studied. Also, the frequency separation that must exist between the channels so that the systems can coexist will be determined. The fourth chapter is based on the simulation of three scenarios of interference between these systems. For this purpose, a radio propagation simulation software package Radio Plan will be used. These simulations will quantify performance losses suffered by systems that interfered. Finally, in chapter five the conclusions about the results of simulations of interference in different scenarios will be presented.

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El proyecto consiste en la actualización del sistema de soporte operacional (OSS) con respecto a las nuevas redes para acceso móvil LTE/4G. El trabajo es un ejercicio real ejercido para Vodafone, compañía de telefonía en España. El producto OSS de Ericsson España es un sistema de supervisión de soporte de la red para cualquier tipo de nodo, pero el proyecto se centrará en los nodos de red LTE (Long Term Evolution). Con este sistema se puede gestionar cualquier cambio en los nodos, incidencias o actualizaciones en la red de manera fiable y sin pérdida de datos. Se profundizará en la descripción del software y del hardware del producto OSS. Se hablará de la tecnología LTE, detallando la evolución sufrida en las redes, el paso de 2G/3G a 4G y todo ello centrado en la industria puntera de las redes de telefonía móviles, así como las nuevas características que esta tecnología aporta y la compatibilidad con las anteriores. ABSTRACT. This project consists of the upgrade of the operational & support system (OSS) regarding the new functionality implemented for the LTE/4G mobile access networks. The project has been implemented in a live environment in Vodafone Spain. Ericsson OSS product consists of a network monitoring system for support and configuration of Core and Radio network elements. This project will be focused on LTE (Long Term Evolution) network nodes. The OSS system can manage any changes in the nodes, incidents or updates to the network in a reliable way without data loss. The description of OSS software and hardware is going to be explained in detail. LTE technology is going to be introduced, detailing the network evolution from 2G/3G to 4G, all focused on the industry leading mobile phone networks and the new features that this technology provides.

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This 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.