Cette thèse porte sur la conception d’amplificateurs de puissance reconfigurables en technologie CMOS avancée pour une application cellulaire de 4ème génération. Dans les systèmes de communication sans fil, le rendement énergétique est un critère primordial qui impacte la durée d’utilisation de la batterie. Principalement déterminé par la consommation d’énergie du transmetteur, il est plus particulièrement lié à celle de l’amplificateur de puissance (PA). Pour les terminaux mobiles de 4ème génération (4G), les techniques de transmission et les modulations utilisées pour atteindre les débits de données visés induisant une dynamique importante du signal à transmettre, l’implémentation de techniques d’amélioration du rendement autour du PA devient indispensable, afin de le reconfigurer en puissance.Nous avons mis au point dans ce travail de recherche des architectures innovantes utilisant les techniques d’amélioration du Power Cell Switching (PCS) et de l’Envelope Tracking (ET). Le double objectif visé étant d’améliorer significativement le rendement pour les faibles niveaux de puissance et d’apporter de la flexibilité par rapport à un PA utilisé seul. Une première architecture utilisant la technique du PCS totalement intégré en technologie CMOS 65nm de STMicroelectronics, mettant en œuvre des transformateurs comme combineurs de puissance, a été réalisée pour valider la fonctionnalité du concept proposé. Puis une deuxième architecture combinant les techniques du PCS et de l’ET a été conçue, afin d’évaluer les avantages qu’apporte la combinaison de ces deux techniques par rapport à un PA fonctionnant seul et à un PA développé utilisant la technique du PCS. / This thesis deals with the design of reconfigurable power amplifiers implemented in CMOS technology for 4G LTE application. For the next generation communication systems such as 4G LTE, orthogonal frequency division multiplexing (OFDM) is employed for a wideband communication. Indeed, signal information is encoded both in amplitude and phase domains, which results in a higher peak to average power ratio than for 2G and 3G systems. Consequently, the overall power amplifier (PA) efficiency does not only depend on efficiency at maximum power, but also and mainly on efficiency at back-off level where the PA operates most of the time. Obviously, classical PA architectures do not address this problem, because it can only achieve maximum efficiency at a single power level, usually around the peak output power. Therefore, the overall efficiency of the PA is considerably low and efficiency improvement techniques are required to increase the battery life-time. This thesis exposes innovative architectures using Power Cell Switching (PCS) and Envelope Tracking (ET) techniques. The main objective of the proposed architectures is to significantly improve the average efficiency in comparison with a stand-alone power amplifier at power back-off. Consequently, a reconfigurable PA architecture using a 4-step PCS technique has been implemented in CMOS 65nm technology. A second architecture was designed to evaluate the improvement obtained with the combination of these two techniques.

The purpose of the study was to find out and analysis the factors that can influence people's choice to mobile network service. Based on our research, we can give some practical advice to consumer and telecom companies.To achieve the purpose of the study we design a questionnaire and send it to our friends in Shanghai and Jinan China. The questionnaire was built around some questions about which factors can influence people’s choice and the importance of each factor.The study was performed with a quantitative research approach. We found five factors that affect users to choose different mobile networks, respectively usefulness, ease of use, price, speed and enjoyment. And in this paper we also proposed five hypotheses to test the relationship between these factors and gender. This provides us the theoretical basis to our research. The factors were included in our questionnaire, so the questionnaire gives the research some basic data. We analyze the data through the processional software SPSS.We have analyzed every aspect of our questionnaire. We put the data together and make visual figures. The figures make people easily understand the questions. Also these data help us understand the phenomena clearly and make a contribution to our study.Based on the findings, the research could be validated with a data analysis which gave grounds for the conclusion part.

Context. The single blackboard architecture is widely used in the LTE application area. Despite its several benefits, this architecture limits synchronization possibilities of the developed systems and increases the signal operational latency. As a result the DSP (Digital Signal Processing) utilization is suboptimal. Objectives. In this thesis, we design a new architecture, which combines concepts of Multi-Blackboards and Pipes & Filters architectures, as a replacement for the current single blackboard architecture at Ericsson. The implementation of the new architecture makes the environment asynchronous. We evaluate the new architecture at simulated environment of Ericsson with 222225 connection items from 9000 base stations all over the world. Each connection item has a complete UE session and one of possible connection statuses, e.g. active, inactive, connected, DRX sleeping, postponed. These connection items can be from any country in the world. Methods. We design a new architecture for UPCUL component of LTE network based on analysis of real network data from Ericsson. We perform a case study to develop and evaluate the new architecture at Ericsson. Results. We evaluate the new architecture by performing a case study at Ericsson. The results of case study show that the new architecture not only increases DSP utilization by 35%, but also decreases signal operational latency by 53%, FO operation time by 20% and FO operation cycles by 20%. Also, the new architecture increases correctness performance. Conclusions.  We conclude that the new architecture increases DSP utilization and decreases the signal operational latency, therefore, improves performances of UPCUL component of LTE.  Due to time constraints, we only considered four LTE FOs (Function Objects) and relative signals. Future work should focus mainly on the other FOs and signals. We also analyze unconsidered FOs, and make an integration solution table which contains solutions to integrate these unconsidered FOs into the new architecture.  The second avenue for future work is to re-size the size of the two blackboard storages. We find out that the maximum memory size of needed UE sessions per sub-frame is only 1.305% of the memory size of all UE sessions (31650 bytes). So the memory size of blackboard storage should be adjusted on the basis of needed UE sessions instead of all UE sessions.

La llegada de redes de cuarta generación cambia el paradigma de creación y consumo de contenidos. Este cambio se sustenta principalmente en las mejoras en la velocidad de conexión que ofrecen estas redes y en el uso de arquitecturas de red de próxima generación (NGN). Ambos factores hacen posible el despliegue de servicios convergentes que se caracterizan por permitir la interacción de servicios tradicionales bajo una misma plataforma. El objetivo del presente trabajo de memoria es la utilización de la arquitectura de red IMS y la red de acceso LTE para el desarrollo de servicios de televisión de próxima generación de carácter convergente y que ofrezcan interfaces gráficas interactivas y amigables, logrando así sacar mayor provecho de las características que ofrecen estas tecnologías de red. Este trabajo es parte de un proyecto de desarrollo continuo del Departamento de Ingeniería Eléctrica de la Facultad de Ciencias Físicas y Matemáticas de la Universidad de Chile que busca la creación de ambientes docentes para el estudio de redes 4G que aún no existen comercialmente en el país. Tras una presentación del contexto y antecedentes respecto a las características principales de los conceptos involucrados, se presenta el diseño de dos servicios de televisión. En primer lugar, se muestra un servicio de IPTV básico que permite la elección flexible de contenido y la interacción con otros usuarios a través de video conferencias, llamadas de voz y mensajería de texto. En segundo lugar, en base al ambiente de creación de servicios Mobicents, se muestra la construcción de una plataforma web para la elección del contenido de video que permite el envío de trailers a dispositivos móviles y la posibilidad de compra de películas. Una vez terminados los diseños, se hace un especial énfasis en detallar la implementación de los servicios mencionados con el propósito de aportar en el proceso de construcción de herramientas para el estudio de redes y facilitar su posterior puesta en marcha. Finalmente, se muestran diversas capturas de tráfico para verificar el correcto funcionamiento de los servicios. En base a estas pruebas, se verifica que el trabajo cumple con los objetivos propuestos, en cuanto se logra la implementación de servicios de televisión convergentes sobre redes LTE en un ambiente de laboratorio controlado y replicable para futuras experiencias. Es relevante el hecho de haber logrado estos desarrollos en base a un ambiente de creación de servicios, pues entrega un punto de partida para continuar con la mejora de estos servicios o la elaboración de nuevas experiencias de laboratorio en trabajos futuros.

El objetivo general del presente trabajo de título es estudiar la tecnología LTE y el posible comportamiento que podría tener la incorporación de esta en Chile, específicamente en los sistemas de datos de alta velocidad como la banda ancha móvil (BAM). El trabajo de título se centra en dos tópicos relevantes, por un lado, el estudio técnico de la tecnología misma y las capacidades que puede entregar, lo que permite fundamentar las ventajas que entregará en comparación a los actuales sistemas de datos de alta velocidad. Y por otro lado, el estudio de tendencia del mercado mundial y nacional de los sistemas móviles, específicamente de la BAM, que permite realizar una proyección a nivel nacional sobre el futuro ingreso de las redes LTE en Chile. Los sistemas de comunicaciones móviles se han ido desarrollando acorde a los nuevos intereses de los usuarios. Las actuales tecnologías permiten conectarse a internet pero con ciertas limitaciones en velocidad, cobertura y movilidad. Lo que se espera con la llegada de LTE es mejorar la experiencia de usuario de tal forma de entregar un servicio de banda ancha similar a las redes de banda ancha fija, pero con la posibilidad de movilidad. En este trabajo se determinan y discuten factores que podrían influir en la entrada de LTE al mercado nacional, tomando en consideración el desarrollo en Chile de los sistemas de banda ancha móvil. Entre ellos se puede mencionar el desarrollo de nuevos dispositivos y servicios, el ingreso de nuevos operadores junto con la aplicación de la portabilidad numérica, el proceso de licitación de bandas de frecuencia, los cambios en la experiencia de usuario, las modificaciones en el modelo de negocio y evaluaciones comerciales de implementar LTE. De esta forma se concluye que los sistemas de banda ancha ofrecidos por LTE serán posibles en el territorio nacional, ya que las compañías locales tienen todas las posibilidades técnicas y regulatorias para incorporar LTE. Esto último se ve reflejado en los compromisos que han asumido EntelPCS y Movistar para desplegar sus redes LTE durante el 2012. Por otra parte, la incorporación de nuevas redes de banda ancha HSPA+ logrará fomentar el uso de la BAM, generando mayor interés por sistemas que siguen la línea de LTE. La llegada de LTE permitirá a las compañías operadores competir con la banda ancha fija ya que ofrecerá una experiencia de usuario similar, lo que permitirá un desarrollo del mercado móvil.

Fourth Generation (4G) cellular technology Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) offers high data rate capabilities to mobile users; and, operators are trying to deliver a true mobile broadband experience over LTE networks. Mobile TV and Video on Demand (VoD) are expected to be the main revenue generators in the near future [36] and efficient video streaming over wireless is the key to enabling this. 3GPP recommends the use of H.264 baseline profiles for all video based services in Third Generation (3G) Universal Mobile Telecommunication System (UMTS) networks. However, LTE networks need to support mobile devices with different display resolution requirements like small resolution mobile phones and high resolution laptops. Scalable Video Coding (SVC) is required to achieve this goal. Feasibility study of SVC for LTE is one of the main agenda of 3GPP Release10. SVC enhances H.264 with a set of new profiles and encoding tools that may be used to produce scalable bit streams. Efficient adaptation methods for SVC video transmission over LTE networks are proposed in this thesis. Advantages of SVC over H.264 are analyzed using real time use cases of mobile video streaming. Further, we study the cross layer adaptation and scheduling schemes for delivering SVC video streams most efficiently to the users in LTE networks in unicast and multicast transmissions. We propose SVC based video streaming scheme for unicast and multicast transmissions in the downlink direction, with dynamic adaptations and a scheduling scheme based on channel quality information from users. Simulation results indicate improved video quality for more number of users in the coverage area and efficient spectrum usage with the proposed methods.

No description available.

The subject of the diploma thesis are procedures in EPS network related to the operation of mobile terminals. In the introduction of my work I described the EPS system, including the quality of services and bearers. The following section focuses on control procedures in the EPS system such as attach network procedure, detach procedure, service request, handover or tracking area procedure. Further, three technologies for Internet of Things were described, namely EC-GSM-IoT, LTE-M and NB-IoT. All the procedures mentioned above were also captured in the experimental VUT EPS network and analyzed by TravelHawk using software M5 and Wireshark. Theoretical and practical findings were subsequently used out for setting of laboratory task for subject MKPM.

The master thesis is focused on control procedures in EPS-IMS networks. Firstly the thesis describes systems IMS and EPS. The second part of thesis includes the theory of control procedures in EPS such as cell acquisition, random access procedure, identification of subscriber, authentication of subscriber, security procedures, tracking area procedure, default bearer creation, implementation of CSFB procedure and detach procedure. Processes related to subsystem IMS such as registration to IMS, bearer creation for IMS signalling and voice service VoLTE are the next part of thesis. The next main topic is the VoLTE implementation problematic and VoLTE cooperation with diverse terminals. There is also explained the principle of Circuit Switched Fallback for realization voice services in EPS without VoLTE service. All procedures mentioned above except of procedures which are related to IMS were captured and analyzed using software Wireshark and QualiPoc. The final part of the thesis is lab task creation based of the analyzed messages.

The purpose of this study was to determine the availability of Internet access for students attending East Tennessee State University during the fall semester 2013. It has been unknown to what degree broadband access is available in the East Tennessee State University service area that includes counties in East Tennessee, Southwest Virginia, and Western North Carolina. The research was conducted during the fall semester 2013 including the months of August, September, and October of 2011. Data were gathered by surveying currently enrolled students of the university. Seven hundred eighty-four students responded to the survey. The survey instrument covered areas of demographics and Internet connection type from home. In addition, the instrument covered usage of 3G/4G Mobile Broadband Service, ETSU computer labs, and high-speed Internet service for coursework. The results of the data analysis provided insight into the availability, frequency of use, and perceived importance of high-speed Internet access for students at ETSU. For example, over 95% of the respondents had either a high-speed Internet connection or 3G/4G Mobile Broadband Service at their place of residence. Fifteen percent were dissatisfied with their current high-speed Internet service. Approximately 70% reported that high-speed Internet service was very important in completing coursework. This study provided an increase in the body of knowledge related to Internet access for ETSU students and the counties surrounding the university.