83 research outputs found

    Myspeedtest: active and passive measurements of cellular data networks

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    As the number and diversity of applications available to mobile users increases, there is an increasing need for developers, network service providers, and users to understand how users perceive the network performance of these applications. MySpeedTest is a measurement tool that actively probes the network to determine not only TCP throughput and round trip time, but also the proximity to popular content providers, IP packet delay variation, and loss. It also records other metadata that could affect user experience, such as signal strength, service provider, connection type, battery state, device type, manufacturer, time of day, and location. The tool also takes passive measurements of the applications installed on the device and the network usage of these applications. My SpeedTest is available on the Google Play Store and currently has 1300+ active users. This thesis presents the design and implementation of MySpeedTest as well as effect of metrics like latency and IP packet delay variation on performance.MSCommittee Chair: Nick Feamster; Committee Member: Patrick Traynor; Committee Member: Raghupathy Sivakuma

    The effects of network factors on the performance of 3G UMTS applications

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    Includes bibliographical references (leaves 139-148).3G is the wireless network technology expected to allow wireless applications to perform on par with wired applications. However 3G has factors which limit its performance. These factors include both device factors such as small screens, limited battery power and life, as well as network factors such as high delay networks and low bandwidths. This thesis investigates the following: how network factors affect the performance of 3G UMTS applications; which network factors have the most significant impact on a specific application; whether there are any minimum requirements needed for an application. Eight popular 3G applications were investigated: FTP, email, MMS, SMS, HTTP web browsing, broadcast media, video calling and streaming media

    Characterization and Optimization of Resource Utilization for Cellular Networks.

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    Cellular data networks have experienced significant growth in the recent years particularly due to the emergence of smartphones. Despite its popularity, there remain two major challenges associated with cellular carriers and their customers: carriers operate under severe resource constraints, while many mobile applications are unaware of the cellular specific characteristics, leading to inefficient radio resource and handset energy utilization. My dissertation is dedicated to address both challenges, aiming at providing practical, effective, and efficient methods to monitor and to reduce the resource utilization and bandwidth consumption in cellular networks. Specifically, from carriers' perspective, we performed the first measurement study to understand the state-of-the-art of resource utilization for a commercial cellular network, and revealed that fundamental limitation of the current resource management policy is treating all traffic according to the same resource management policy globally configured for all users. On mobile applications' side, we developed a novel data analysis framework called ARO (mobile Application Resource Optimizer), the first tool that exposes the interaction between mobile applications and the radio resource management policy, to reveal inefficient resource usage due to a lack of transparency in the lower-layer protocol behavior. ARO revealed that many popular applications built by professional developers have significant resource utilization inefficiencies that are previously unknown. Motivated by the observations from both sides, we further proposed a novel resource management framework that enables the cooperation between handsets and the network to allow adaptive resource release, therefore better balancing the key tradeoffs in cellular networks. We also investigated the problem of reducing the bandwidth consumption in cellular networks by performing the first network-wide study of HTTP caching on smartphones due to its popularity. Our findings suggest that for web caching, there exists a huge gap between the protocol specification and the protocol implementation on today's mobile devices, leading to significant amount of redundant network traffic.PHDComputer Science and EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/94024/1/fengqian_1.pd

    WSN and M2M for mountain biking performance assessment

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    The thesis describes the design and implementation of the "Smart Mountain Bike” monitoring system enables the acquisition, storage and visualization of data on athlete training referring the cycling activity. The signals provided by the measurement channels are acquired and processed in order to better understand of the variables involved in this sport and consecutively to improve the methodology for the training of athletes. The "Smart Mountain Bike" system consists of a wireless sensor network that acquire data related to the applied force and body position during a training session. Each network end node comprises a microcontroller, a conditioning circuit and a set of sensors. The coordinator node Zig Bee compatible is composed by microcomputer (eg. Raspberry PI or BeagleBone), a GPS and an IMU. The cloud interfacing is done using a 3G/UMTS USB module connected to the microcomputer board. As the main component of the cloud the implemented database is accessed through a mobile application implemented in an Android OS device. The mobile application allows the visualization of the acquired and processed data by the user expressed by the athlete or the coach. This system can be used for other sports and other activities in which it is necessary to monitor physical activities such as physical therapy.Este documento descreve o desenvolvimento de um protótipo "Smart Mountain Bike", este sistema de monitorização permite a recolha, armazenamento e visualização dos dados relativos aos treinos do atleta durante a atividade ciclismo. Esta informação contribui para um melhor entendimento das variáveis envolvidas da prática deste desporto e consecutivamente, melhorar a metodologia de treino dos atletas. O sistema "Smart Mountain Bike" é constituído por uma rede sensores sem fios que recolhe a dados sobre força aplicada e posição do corpo numa sessão de treino, cada nó final da rede é composto por um microcontrolador, um circuito condicionador e um conjunto de sensores. O nó coordenador é composto por um microcomputador, um recetor GPS, um IMU e um módulo de comunicação móvel, este módulo permite um cenário Machine-to-Machine, onde o microcomputador comunica com o a nuvem permitindo o armazenamento da informação recolhida numa base de dados. Esta informação é acedida através de uma aplicação móvel desenvolvida para este projeto, a aplicação móvel permite ao utilizador, atleta ou treinador, visualizar e correlacionar os dados. Este sistema pode ser utilizado noutros desportos e noutras atividades em que seja necessário monitorizar atividades físicas, como por exemplo, fisioterapi

    The strategies associated with the migration of networks to 4G

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    The networks need to provide higher speeds than those offered today. For it, considering that in the spectrum radio technologies is the scarcest resource in the development of these technologies and the new developments is essential to maximize the performance of bits per hertz transmitted. Long Term Evolution optimize spectral efficiency modulations with new air interface, and more advanced algorithms radius. These capabilities is the fact that LTE is an IPbased technology that enables end-to-end offer high transmission rates per user and very low latency, ie delay in the response times of the network around only 10 milliseconds, so you can offer any realtime application. LTE is the latest standard in mobile network technology and 3GPP ensure competitiveness in the future, may be considered a technology bridge between 3G networks - current 3.5G and future 4G networks, which are expected to reach speeds of up to 1G . LTE operators provide a simplified architecture but both robust, supporting services on IP technology. The objectives to be achieved through its implementation are ambitious, first users have a wide range of added services like capabilities that currently enjoys with residential broadband access at competitive prices, while the operator will have a network fully IP-based environment, reducing the complexity and cost of the same, which will give operators the opportunity to migrate to LTE directly. A major advantage of LTE is its ability to fuse with existing networks, ensuring interconnection with the same, increasing his current coverage and allowing a data connection established by a user in the environment continue when fade the coverage LTE. Moreover, the operator has the advantage of deploying network gradually, starting initially at areas of high demand for broadband services and expand progressively in line with this. RESUMEN. Las redes necesitan proporcionar velocidades mayores a las ofertadas a día de hoy. Para ello, teniendo en cuenta que en tecnologías radio el espectro es el recurso más escaso, en la evolución de estas tecnologías y en los nuevos desarrollos es esencial maximizar el rendimiento de bits por hercio transmitido. Long Term Evolution optimiza la eficiencia espectral con nuevas modulaciones en la interfaz aire, así como los algoritmos radio más avanzado. A estas capacidades se suma el hecho de que LTE es una tecnología basada en IP de extremo a extremo que permite ofrecer altas velocidades de transmisión por usuario y latencias muy bajas, es decir, retardos en los tiempos de respuesta de la red en torno a sólo 10 milisegundos, por lo que permite ofrecer cualquier tipo de aplicación en tiempo real. LTE es el último estándar en tecnología de redes móviles y asegurará la competitividad de 3GPP en el futuro, pudiendo ser considerada una tecnología puente entre las redes 3G – 3.5G actuales y las futuras redes 4G, de las que se esperan alcanzar velocidades de hasta 1G. LTE proporcionará a las operadoras una arquitectura simplificada pero robusta a la vez, soportando servicios sobre tecnología IP. Los objetivos que se persiguen con su implantación son ambiciosos, por una parte los usuarios dispondrá de una amplia oferta de servicios añadidos con capacidades similares a las que disfruta actualmente con accesos a banda ancha residencial y a precios competitivos, mientras que el operador dispondrá de una red basada en entorno totalmente IP, reduciendo la complejidad y el costo de la misma, lo que dará a las operadoras la oportunidad de migrar a LTE directamente. Una gran ventaja de LTE es su capacidad para fusionarse con las redes existentes, asegurando la interconexión con las mismas, aumentando su actual cobertura y permitiendo que una conexión de datos establecida por un usuario en el entorno LTE continúe cuando la cobertura LTE se desvanezca. Por otra parte el operador tiene la ventaja de desplegar la red LTE de forma gradual, comenzando inicialmente por las áreas de gran demanda de servicios de banda ancha y ampliarla progresivamente en función de ésta

    Validation platform specification – D5.1

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    Deliverable D5.1 del projecte Europeu OneFIT (ICT-2009-257385)The present deliverable introduces the OneFIT Proof-of-Concept (PoC) Architecture which will be used as a basis for the validation platform development throughout the project. This PoC Architecture proposal is validated by identifying the roles of the various components in the framework of the OneFIT Scenarios as derived and detailed in WP2. The applied methodology ensures that all required features are appropriately considered. Furthermore, the hardware components available to the project are detailed which are the basis for the development of an integrated validation platform. Their role is highlighted by an instantiation step which maps the PoC Architecture components to the identified hardware components. Finally, a scenario instantiation is derived which illustrates the role of the various hardware components for the validation of selected OneFIT scenarios.Postprint (published version

    Mobile three-dimensional city maps

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    Maps are visual representations of environments and the objects within, depicting their spatial relations. They are mainly used in navigation, where they act as external information sources, supporting observation and decision making processes. Map design, or the art-science of cartography, has led to simplification of the environment, where the naturally three-dimensional environment has been abstracted to a two-dimensional representation, populated with simple geometrical shapes and symbols. However, abstract representation requires a map reading ability. Modern technology has reached the level where maps can be expressed in digital form, having selectable, scalable, browsable and updatable content. Maps may no longer even be limited to two dimensions, nor to an abstract form. When a real world based virtual environment is created, a 3D map is born. Given a realistic representation, would the user no longer need to interpret the map, and be able to navigate in an inherently intuitive manner? To answer this question, one needs a mobile test platform. But can a 3D map, a resource hungry real virtual environment, exist on such resource limited devices? This dissertation approaches the technical challenges posed by mobile 3D maps in a constructive manner, identifying the problems, developing solutions and providing answers by creating a functional system. The case focuses on urban environments. First, optimization methods for rendering large, static 3D city models are researched and a solution provided by combining visibility culling, level-of-detail management and out-of-core rendering, suited for mobile 3D maps. Then, the potential of mobile networking is addressed, developing efficient and scalable methods for progressive content downloading and dynamic entity management. Finally, a 3D navigation interface is developed for mobile devices, and the research validated with measurements and field experiments. It is found that near realistic mobile 3D city maps can exist in current mobile phones, and the rendering rates are excellent in 3D hardware enabled devices. Such 3D maps can also be transferred and rendered on-the-fly sufficiently fast for navigation use over cellular networks. Real world entities such as pedestrians or public transportation can be tracked and presented in a scalable manner. Mobile 3D maps are useful for navigation, but their usability depends highly on interaction methods - the potentially intuitive representation does not imply, for example, faster navigation than with a professional 2D street map. In addition, the physical interface limits the usability

    3G Wideband CDMA : packet-based optimisation for high data-rate downlink transmission

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    A third generation (3G) of mobile communication systems, based on Wideband CDMA, are intended to offer high-speed packet-based services. Network operators wish to maximise the throughput in the downlink of3G systems, which requires efficient allocation ofresources. This thesis considers the problem ofmaximising throughput in an interference dominated channel. Cooperative broadcasting is a theoretical technique to mitigate this problem. Its implementation in practical systems requires efficient resource allocati.on to maximise the thr(oughput whilst meeting system and user-imposed constramts. A resource allocation approach is presented for implementing cooperative broadcasting. Users are paired and a teclmique for allocating resources between the pair is developed. Then, a method for pairing the users is considered. Simulation results are presented, which show a throughput improvement over existing resource allocation approaches. The problem ofcontrolling the distribution ofrandomly arriving data to meet the resource allocation specifications is examined. A single-threshold buffer is proposed, which requires fewer calculations than an existing double-threshold buffer. Simulation results are presented which show a throughput improvement may be realised, greater than that which would achievable using other rate control schemes. Cooperative broadcasting may lead to transmissions to some users being allocated low power. When full channel infonnation is available at the transmitter, a water filling solution may be used to maximise capacity. However, when combined with buffer management, erasure may result. This erasure may be overcome using an erasure protection code. Such a code is examined. When combined with Turbo coding, ajoint detector may be used for providing error and erasure protection. Analysis ofthis detector shows a lower limit on the error rate, dependent on the probability of erasure. Simulation results show that using this approach the error rate is significantly improved. This code can then be used to increase capacity, whilst achieving low error rates.Imperial Users onl
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