Physical Layer Techniques for Wireless Communication Systems

The increasing diffusion of mobile devices requiring, everywhere and every time, reliable connections able to support the more common applications, induced in the last years the deployment of telecommunication networks based on technologies capable to respond effectively to the ever-increasing market demand, still a long way off from saturation level. Multicarrier transmission techniques employed in standards for local networks (Wi-Fi) and metropolitan networks (WiMAX) and for many years hot research topic, have been definitely adopted beginning from the fourth generation of cellular systems (LTE). The adoption of multicarrier signaling techniques if on one hand has brought significant advantages to counteract the detrimental effects in environments with particularly harsh propagation channel, on the other hand, has imposed very strict requirements on sensitivity to recovery errors of the carrier frequency offset (CFO) due to the resulting impact on correct signal detection. The main focus of the thesis falls in this area, investigating some aspects relating to synchronization procedures for system based on multicarrier signaling. Particular reference will be made to a network entry procedure for LTE networks and to CFO recovery for OFDM, fltered multitone modulation and direct conversion receivers. Other contributions pertaining to physical layer issues for communication systems, both radio and over acoustic carrier, conclude the thesis

Mobile Ad Hoc Networks

Guiding readers through the basics of these rapidly emerging networks to more advanced concepts and future expectations, Mobile Ad hoc Networks: Current Status and Future Trends identifies and examines the most pressing research issues in Mobile Ad hoc Networks (MANETs). Containing the contributions of leading researchers, industry professionals, and academics, this forward-looking reference provides an authoritative perspective of the state of the art in MANETs. The book includes surveys of recent publications that investigate key areas of interest such as limited resources and the mobility of mobile nodes. It considers routing, multicast, energy, security, channel assignment, and ensuring quality of service. Also suitable as a text for graduate students, the book is organized into three sections: Fundamentals of MANET Modeling and Simulation—Describes how MANETs operate and perform through simulations and models Communication Protocols of MANETs—Presents cutting-edge research on key issues, including MAC layer issues and routing in high mobility Future Networks Inspired By MANETs—Tackles open research issues and emerging trends Illustrating the role MANETs are likely to play in future networks, this book supplies the foundation and insight you will need to make your own contributions to the field. It includes coverage of routing protocols, modeling and simulations tools, intelligent optimization techniques to multicriteria routing, security issues in FHAMIPv6, connecting moving smart objects to the Internet, underwater sensor networks, wireless mesh network architecture and protocols, adaptive routing provision using Bayesian inference, and adaptive flow control in transport layer using genetic algorithms

Mobile Ad Hoc Networks

Guiding readers through the basics of these rapidly emerging networks to more advanced concepts and future expectations, Mobile Ad hoc Networks: Current Status and Future Trends identifies and examines the most pressing research issues in Mobile Ad hoc Networks (MANETs). Containing the contributions of leading researchers, industry professionals, and academics, this forward-looking reference provides an authoritative perspective of the state of the art in MANETs. The book includes surveys of recent publications that investigate key areas of interest such as limited resources and the mobility of mobile nodes. It considers routing, multicast, energy, security, channel assignment, and ensuring quality of service. Also suitable as a text for graduate students, the book is organized into three sections: Fundamentals of MANET Modeling and Simulation—Describes how MANETs operate and perform through simulations and models Communication Protocols of MANETs—Presents cutting-edge research on key issues, including MAC layer issues and routing in high mobility Future Networks Inspired By MANETs—Tackles open research issues and emerging trends Illustrating the role MANETs are likely to play in future networks, this book supplies the foundation and insight you will need to make your own contributions to the field. It includes coverage of routing protocols, modeling and simulations tools, intelligent optimization techniques to multicriteria routing, security issues in FHAMIPv6, connecting moving smart objects to the Internet, underwater sensor networks, wireless mesh network architecture and protocols, adaptive routing provision using Bayesian inference, and adaptive flow control in transport layer using genetic algorithms

Integrated Architecture for Configuration and Service Management in MANET Environments

Esta tesis nos ha permitido trasladar algunos conceptos teóricos de la computación ubicua a escenarios reales, identificando las necesidades específicas de diferentes tipos de aplicaciones. Con el fin de alcanzar este objetivo, proponemos dos prototipos que proporcionan servicios sensibles al contexto en diferentes entornos, tales como conferencias o salas de recuperación en hospitales. Estos prototipos experimentales explotan la tecnología Bluetooth para ofrecer información basada en las preferencias del usuario. En ambos casos, hemos llevado a cabo algunos experimentos con el fin de evaluar el comportamiento de los sistemas y su rendimento. También abordamos en esta tesis el problema de la autoconfiguración de redes MANET basadas en el estándar 802.11 a través de dos soluciones novedosas. La primera es una solución centralizada que se basa en la tecnología Bluetooth, mientras la segunda es una solución distribuida que no necesita recurrir a ninguna tecnología adicional, ya que se basa en el uso del parámetro SSID. Ambos métodos se han diseñado para permitir que usuarios no expertos puedan unirse a una red MANET de forma transparente, proporcionando una configuración automática, rápida, y fiable de los terminales. Los resultados experimentales en implementaciones reales nos han permitido evaluar el rendimiento de las soluciones propuestas y demostrar que las estaciones cercanas se pueden configurar en pocos segundos. Además, hemos comparado ambas soluciones entre sí para poner de manifiesto las diferentes ventajas y desventajas en cuanto a rendimento. La principal contribución de esta tesis es EasyMANET, una plataforma ampliable y configurable cuyo objetivo es automatizar lo máximo posible las tareas que afectan a la configuración y puesta en marcha de redes MANET, de modo que su uso sea más simple y accesible.Cano Reyes, J. (2012). Integrated Architecture for Configuration and Service Management in MANET Environments [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/14675Palanci

A coarse-grained dynamically reconfigurable MAC processor for power-sensitive multi-standard devices

DRMP, a Dynamically Reconfigurable MAC Processor, is an innovative, dynamically reconfigurable System-on-Chip architecture. The architecture exploits substantial overlaps in the functionality of different wireless MAC layers. Its flexibility is specialized for addressing the requirements of the MAC layer of wireless standards. It is targeted at consumer, multi-standard, handheld devices, and its design is meant to address the balance of flexibility and power-efficiency that this target market demands. The DRMP reconfigures packet-by-packet on the fly, allowing execution of concurrent protocol modes on a single hardware co-processor. An interrupt-driven programming model has also been presented and shown to implement the protocol state-machine of the three protocols on a CPU. These features will allow the DRMP to replace three MAC processors in a hand-held device. The most innovative component of the DRMP architecture is its Interface and Reconfiguration Controller. It uses a combination of asynchronous controllers to dynamically reconfigure the functional units in the architecture and delegate MAC tasks to them. The architecture has been modeled in Simulink at cycle-approximate abstraction. Results of simulations involving transmission and reception of packets have been presented, showing that the platform concurrently handles three protocol streams, reconfigures dynamically, yet meets and exceeds the protocol timing constraints, all at a moderate frequency. Its heterogeneous and coarse-grained functional units, limited connectivity requirements between these units, and proportionally large time that these resources are idle, promise a very modest power-consumption, suitable for mobile devices, while offering flexibility to implement different MAC protocols

Modernisation and Innovation Management: Developing a Digital Society. An investigation into public sector modernisation and innovation management in its introduction of wireless technology.

This thesis presents an exploratory study into the development of digital societies and it examines public sector modernization and innovation from a technology management perspective. The study presents reasons why most city-wide or council-wide development of wireless broadband access networks currently end in failure or are unsustainable. It also suggests its links with wider problems of innovation management and the commercial failure of otherwise technically competent solutions It explores the modernisation of society, government, the underlying theories that influence it as well as the innovations triggered by its wake. The exercise reveals a myriad of innovations; firstly in the modernisation of the infrastructure of government and secondly in the development of societal infrastructure in the form of broadband networks

Optimisation of wireless communication system by exploitation of channel diversity

Communication systems are susceptible to degradation in performance because of interference received through their side lobes. The interference may be deliberate electronic counter measure (ECM), Accidental RF Interference (RFI) or natural noise. The growth of interference communication systems have given rise to different algorithms, Adaptive array techniques offer a possible solution to this problem of interference received through side lobes because of their automatic null steering in both spatial and frequency domains. Key requirement for space-time architecture is to use robust adaptive algorithms to ensure reliable operation of the smart antenna. Space division multiple access (SDMA) involves the use of adaptive nulling to allow two or more users (mobiles) in the same cell to share same frequency and time slot. One beam is formed for each user with nulls in the direction of other users. Different approaches have been used to identify the interferer from desired user. Thus a basic model for determining the angle of arrival of incoming signals, an appropriate antenna beam forming and adaptive algorithms are used for array processing. There is an insatiable demand for capacity in wireless data networks and cellular radio communication systems. However the RF environment that these systems operate in is harsh and severely limits the capacity of traditional digital wireless networks. With normal wireless systems this limits the data rate in cellular radio environments to approximately 200 kbps whereas much higher data rates in excess of 25Mbps are required. A common wireless channel problem is that of frequency selective multi-path fading. To combat this problem, new types of wireless interface are being developed which utilise space, time and frequency diversity to provide increasing resilience to the channel imperfections. At any instant in time, the channel conditions may be such that one or more of these diversity methods may offer a superior performance to the other diversity methods. The overall aim of the research is to develop new systems that use a novel combination of smart antenna MIMO techniques and an advanced communication system based on advanced system configuration that could be exploited by IEEE 802.20 user specification approach for broadband wireless networking. The new system combines the Multi-input Multi-output communication system with frequency diversity in the form of an OFDM modulator. The benefits of each approach are examined under similar channel conditions and results presented.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Contribution to the Design and Operation of Advanced Mobile Communlcations Systems

El objetivo de esta tesis es estudiar la capacidad de los sistemas LTE (LongTerm Evolution) y Mobile WiMAX (Mobi/e Worldwide fnteroperab;/ity far Microwave Access), definida ésta como "el número máximo de usuarios simultáneos, con diferentes perfiles de servicios, que puede soportar cada nodo de acceso, para cada configuración del sistema". Para poder calcular ésta y la tasa binaria (throughput) se requiere primero calcular dinámicamente !a cantidad de recursos demandados y disponibles, que, a su vez, dependen de cómo se forma la correspondiente MAU (Mínimum Allocation Unit), tanto en LTE como en WiMAX. Ambas tecnologías, propuestas como respuesta a la iniciativa IMT (lnternational Mobile Telecommunications)-Advanced, tienen en común que el cómputo de estos MAUs es complejo debido a que parte de los recursos (overhead) tiene que utilizarse para labores necesarias de señalización, control o sincronización. Aunque el conjunto de tecnologías 3G (Third Generation) basadas en WCDMA (Wide-bond Code Division Mu/tiple Access) y HSPA (High-Speed Packet Access) constituyen en la actualidad el fundamento de las redes móviles de banda ancha más empleadas, LTE es, sin embargo, la tecnología móvil con el crecimiento más rápido de toda la historia. LTE es capaz de proporcionar velocidades de datos muy elevadas con una latencia extremadamente reducida, especialmente en el enlace descendente, DL (downlink), a expensas de incrementar su complejidad. Éstas son algunas de las características que convierten a LTE en una tecnología de banda ancha móvil con enormes posibilidades, no solo para usuarios domésticos sino también para aplicaciones novedosas en comunicaciones M2M (machine-to-machine), servicios de salud tipo mHea/th, los nuevos servicios asociados a las ciudades inteligentes (smart grids). Hay varias razones que explican este rápido despliegue de las redes LTE. Por un lado, el mercado de dispositivos móviles está creciente a tasas muy elevadas(::: 80%), constituyendo ya los teléfonos inteligentes (smartphones) el 75% de los dispositivos de usuario. Por otro lado, la técnica OFDMA (Orthogonal Frequency Division Mu/tiple Access) en el enlace descendente permite que LTE sea capaz de soportar tasas de datos más elevadas que las de HSPA. Hay incluso nuevos comportamientos de usuarios, sobre todo del segmento de población más joven, que están modificando sus preferencias a la hora de ver TV, desplazándose progresivamente desde el televisor convencional al streaming en sus smartphones. La combinación de todos estos factores está espoleando una demanda fuertemente creciente de servicios novedosos y muy intensivos en Mbps (HDTV, vídeo bajo demanda (VoG), gaming, etc.): el tráfico de datos ha crecido un ::: 65% entre los primeros cuatrimestres de 2015 y 2016. Además de la utilización de OFDM, LTE y Mobile-WiMAX tiene otros aspectos en común, como la posible integración de técnicas AMC (Adaptive Modulation and Cading) y MIMO (Multip/elnput ond Multip/e-Output) para poder proveer conexiones más fiables y rápidas. Sin embargo, y a pesar de estas similitudes, LTE y Mobile-WiMAX constituyen soluciones tecnológicas muy complejas que exhiben numerosas diferencias. En particular, un elemento crucial que aumenta la dificultan inherente a ambas se encuentra se encuentra en su flexibilidad en el sentido de que se dejan abiertos muchos aspectos de configuración para que cada empresa pueda diseñar la opción que considere más adecuada. El rendimiento de estas redes depende pues de la forma en la que se soluciona el problema de optimización entre la adecuación de los recursos disponibles en cada configuración a los recursos consumidos por !os usuarios. En esta Tesis se realiza diferentes trabajos de investigación tendentes a: 1. Modelar de forma exacta la velocidad de datos (throughput) disponible para los usuarios. Esto requiere calcular en paralelo los recursos disponibles -una vez descontado el overhead -y los recursos demandados. 2. Calcular, utilizando la heurística anterior, !a capacidad (o número máximo de usuarios simultáneos, con diferentes perfiles de servicios, que puede soportar cada nodo de acceso, para cada configuración del sistema). La validez de los modelos obtenidos se ha probado de forma exitosa en una gran variedad de configuraciones posibles en ambas tecnologías, publicando !os resultados en varias revistas y congresos internacionales