Multimedia delivery in the future internet

The term “Networked Media” implies that all kinds of media including text, image, 3D graphics, audio and video are produced, distributed, shared, managed and consumed on-line through various networks, like the Internet, Fiber, WiFi, WiMAX, GPRS, 3G and so on, in a convergent manner [1]. This white paper is the contribution of the Media Delivery Platform (MDP) cluster and aims to cover the Networked challenges of the Networked Media in the transition to the Future of the Internet. Internet has evolved and changed the way we work and live. End users of the Internet have been confronted with a bewildering range of media, services and applications and of technological innovations concerning media formats, wireless networks, terminal types and capabilities. And there is little evidence that the pace of this innovation is slowing. Today, over one billion of users access the Internet on regular basis, more than 100 million users have downloaded at least one (multi)media file and over 47 millions of them do so regularly, searching in more than 160 Exabytes1 of content. In the near future these numbers are expected to exponentially rise. It is expected that the Internet content will be increased by at least a factor of 6, rising to more than 990 Exabytes before 2012, fuelled mainly by the users themselves. Moreover, it is envisaged that in a near- to mid-term future, the Internet will provide the means to share and distribute (new) multimedia content and services with superior quality and striking flexibility, in a trusted and personalized way, improving citizens’ quality of life, working conditions, edutainment and safety. In this evolving environment, new transport protocols, new multimedia encoding schemes, cross-layer inthe network adaptation, machine-to-machine communication (including RFIDs), rich 3D content as well as community networks and the use of peer-to-peer (P2P) overlays are expected to generate new models of interaction and cooperation, and be able to support enhanced perceived quality-of-experience (PQoE) and innovative applications “on the move”, like virtual collaboration environments, personalised services/ media, virtual sport groups, on-line gaming, edutainment. In this context, the interaction with content combined with interactive/multimedia search capabilities across distributed repositories, opportunistic P2P networks and the dynamic adaptation to the characteristics of diverse mobile terminals are expected to contribute towards such a vision. Based on work that has taken place in a number of EC co-funded projects, in Framework Program 6 (FP6) and Framework Program 7 (FP7), a group of experts and technology visionaries have voluntarily contributed in this white paper aiming to describe the status, the state-of-the art, the challenges and the way ahead in the area of Content Aware media delivery platforms

QoE de streaming de vídeo em redes veiculares com multihoming

With the ever-increasing interest and availability of vehicular networks, it is important to study the Quality-of-Experience provided by these networks, which ultimately determines the general public perception and thus the overall user adoption. The broad Internet access, the evolution of user equipment, such as smartphones, tablets and personal computers, and the appearance of services like Youtube and Netflix, is leading the user content consumption to be more and more in the form of video streaming. Either motivated by safety or commercial applications, video streaming in such highly mobile environments offers multiple challenges. This dissertation evaluates the QoE of a multihoming communication strategy, supported simultaneously byWAVE and Wi-Fi, for increasing the reliability and performance of video streams in these environments. Furthermore, it also investigates how distinct network functionalities, such as multihoming load balance, buffering, and network metrics such as throughput and latency affect the overall QoE observed. The results obtained led to the proposal of a multihoming load balance policy for video applications based on access technologies, aiming to improve QoE. The overall results show that QoE improves by 7.5% using the proposed approach.Com o aumento contínuo do interesse e disponibilidade de redes veiculares, é importante agora estudar a Qualidade de Experiência fornecida por estas redes, que fundamentalmente determina a opinião e a percepção do público geral sobre um dado serviço. O vasto acesso à Internet, a evolução dos equipamentos, como os telemóveis atuais, tablets e computadores pessoais, e o aparecimento de serviços como o YouTube e o Netflix, está a fazer com que o conteúdo mais consumido seja cada vez mais em forma de streaming de vídeo. Quer seja motivado por aplicações de segurança ou comerciais, o streaming de vídeo em ambientes altamente móveis levanta vários desafios. Esta dissertação avalia a Qualidade de Experiência de técnicas de multihoming, permitindo o uso de diferentes tecnologias de comunicação, como o WAVE e o Wi-Fi, para aumentar a fiabilidade e desempenho de streams de vídeo nestes ambientes. Para além disso, investiga também como é que diferentes mecanismos de rede, como o balanceamento, multihoming e o buffering, e métricas como a taxa de transferência e latência, afetam a QoE observada. Os resultados obtidos levaram à proposta de uma política de divisão de tráfego para aplicações de vídeo baseada em tecnologias de acesso para situações de multihoming, visando uma melhoria da QoE do utilizador. Utilizando o método proposto, os resultados mostram que a experiência do utilizador tem uma melhoria de 7,5%.Mestrado em Engenharia de Computadores e Telemátic

Experimentation and Characterization of Mobile Broadband Networks

The Internet has brought substantial changes to our life as the main tool to access a large variety of services and applications. Internet distributed nature and technological improvements lead to new challenges for researchers, service providers, and network administrators. Internet traffic measurement and analysis is one of the most trivial and powerful tools to study such a complex environment from different aspects. Mobile BroadBand (MBB) networks have become one of the main means to access the Internet. MBB networks are evolving at a rapid pace with technology enhancements that promise drastic improvements in capacity, connectivity, and coverage, i.e., better performance in general. Open experimentation with operational MBB networks in the wild is currently a fundamental requirement of the research community in its endeavor to address the need for innovative solutions for mobile communications. There is a strong need for objective data relating to stability and performance of MBB (e.g., 2G, 3G, 4G, and soon-to-come 5G) networks and for tools that rigorously and scientifically assess their performance. Thus, measuring end user performance in such an environment is a challenge that calls for large-scale measurements and profound analysis of the collected data. The intertwining of technologies, protocols, and setups makes it even more complicated to design scientifically sound and robust measurement campaigns. In such a complex scenario, the randomness of the wireless access channel coupled with the often unknown operator configurations makes this scenario even more challenging. In this thesis, we introduce the MONROE measurement platform: an open access and flexible hardware-based platform for measurements on operational MBB networks. The MONROE platform enables accurate, realistic, and meaningful assessment of the performance and reliability of MBB networks. We detail the challenges we overcame while building and testing the MONROE testbed and argue our design and implementation choices accordingly. Measurements are designed to stress performance of MBB networks at different network layers by proposing scalable experiments and methodologies. We study: (i) Network layer performance, characterizing and possibly estimating the download speed offered by commercial MBB networks; (ii) End users’ Quality of Experience (QoE), specifically targeting the web performance of HTTP1.1/TLS and HTTP2 on various popular web sites; (iii) Implication of roaming in Europe, understanding the roaming ecosystem in Europe after the "Roam like Home" initiative; and (iv) A novel adaptive scheduler family with deadline is proposed for multihomed devices that only require a very coarse knowledge of the wireless bandwidth. Our results comprise different contributions in the scope of each research topic. To put it in a nutshell, we pinpoint the impact of different network configurations that further complicate the picture and hopefully contribute to the debate about performance assessment in MBB networks. The MBB users web performance shows that HTTP1.1/TLS is very similar to HTTP2 in our large-scale measurements. Furthermore, we observe that roaming is well supported for the monitored operators and the operators using the same approach for routing roaming traffic. The proposed adaptive schedulers for content upload in multihomed devices are evaluated in both numerical simulations and real mobile nodes. Simulation results show that the adaptive solutions can effectively leverage the fundamental tradeoff between the upload cost and completion time, despite unpredictable variations in available bandwidth of wireless interfaces. Experiments in the real mobile nodes provided by the MONROE platform confirm the findings

Descentralização da gestão da mobilidade IP nas redes do futuro

Doutoramento em Engenharia ElectrotécnicaThe massive adoption of sophisticated mobile devices and applications led to the increase of mobile data in the last decade, which it is expected to continue. This increase of mobile data negatively impacts the network planning and dimension, since core networks are heavy centralized. Mobile operators are investigating atten network architectures that distribute the responsibility of providing connectivity and mobility, in order to improve the network scalability and performance. Moreover, service providers are moving the content servers closer to the user, in order to ensure high availability and performance of content delivery. Besides the e orts to overcome the explosion of mobile data, current mobility management models are heavy centralized to ensure reachability and session continuity to the users connected to the network. Nowadays, deployed architectures have a small number of centralized mobility anchors managing the mobile data and the mobility context of millions of users, which introduces issues related to performance and scalability that require costly network mechanisms. The mobility management needs to be rethought out-of-the box to cope with atten network architectures and distributed content servers closer to the user, which is the purpose of the work developed in this Thesis. The Thesis starts with a characterization of mobility management into well-de ned functional blocks, their interaction and potential grouping. The decentralized mobility management is studied through analytical models and simulations, in which di erent mobility approaches distinctly distribute the mobility management functionalities through the network. The outcome of this study showed that decentralized mobility management brings advantages. Hence, it was proposed a novel distributed and dynamic mobility management approach, which is exhaustively evaluated through analytical models, simulations and testbed experiments. The proposed approach is also integrated with seamless horizontal handover mechanisms, as well as evaluated in vehicular environments. The mobility mechanisms are also speci ed for multihomed scenarios, in order to provide data o oading with IP mobility from cellular to other access networks. In the pursuing of the optimized mobile routing path, a novel network-based strategy for localized mobility is addressed, in which a replication binding system is deployed in the mobility anchors distributed through the access routers and gateways. Finally, we go further in the mobility anchoring subject, presenting a context-aware adaptive IP mobility anchoring model that dynamically assigns the mobility anchors that provide the optimized routing path to a session, based on the user and network context. The integration of dynamic and distributed concepts in the mobility management, such as context-aware adaptive mobility anchoring and dynamic mobility support, allow the optimization of network resources and the improvement of user experience. The overall outcome demonstrates that decentralized mobility management is a promising direction, hence, its ideas should be taken into account by mobile operators in the deployment of future networks.Na última década verificou-se uma massificação dos dispositivos móveis e das suas aplicações, o que tem vindo a aumentar o consumo de dados móveis. Este aumento dificulta o planeamento e dimensionamento das redes devido principalmente aos modelos extremamente centralizados adoptados por estas. Os operadores móveis têm vindo a estudar modelos mais até para as redes, os quais distribuem a responsabilidade de fornecer conectividade e mobilidade, no sentido de melhorar a escalabilidade e desempenho da rede. Além disso, de forma a garantir um desempenho elevado na entrega dos conteúdos, os fornecedores de serviço têm vindo a mover os servidores de conteúdos para locais mais próximos do utilizador. Apesar do esforço na procura de soluções para o crescente consumo de dados móveis, os modelos atuais de gestão de mobilidade são demasiado centralizados para conseguir assegurar a continuidade de sessão aos utilizadores conectados à rede. As arquiteturas implementadas têm um número muito reduzido de âncoras móveis centralizadas que gerem todos os dados móveis e a informação de contexto da mobilidade, o que leva a uma diminuição de desempenho e escalabilidade, solucionadas através de mecanismos de rede dispendiosos. A gestão da mobilidade precisa de ser repensada de forma a poder lidar com arquiteturas de rede até com a distribuição dos servidores de conteúdos para nós mais próximos dos utilizadores, que é o objectivo principal da Tese apresentada. Primeiro, é apresentada a caracterização da gestão de mobilidade em blocos funcionais, a interação entre eles e potenciais agrupamentos dos mesmos. A gestão da mobilidade descentralizada é estudada através de modelos analíticos e simulações, em que diferentes abordagens distribuem as funcionalidades da mobilidade pela rede. Como resultado deste estudo verificou-se que a descentralização da mobilidade traz vantagens claras. Com base nestes resultados foi proposta uma nova abordagem de gestão de mobilidade distribuída e dinâmica, que é exaustivamente avaliada através de modelos analíticos, simulações e experiências numa bancada de testes. A abordagem proposta é também integrada com mecanismos de handovers horizontais transparentes, assim como é avaliada em ambientes veiculares. Os mecanismos de mobilidade da abordagem proposta são também especificados para cenários de multihoming, de forma a proporcionar o offloading de dados com suporte de mobilidade das redes celulares para outras redes de acesso. Com o objectivo de optimizar o encaminhamento de dados móveis, foi criada uma nova estratégia para o suporte da mobilidade localizada, em que um sistema de replicação de bindings é integrado nas âncoras de mobilidade distribuídas através dos routers de acesso e dos gateways. Finalmente apresenta-se um modelo de ancoramento adaptativo para a mobilidade com base em contexto, o qual dinamicamente determina as âncoras de mobilidade que oferecem a melhor rota para uma dada sessão, baseado na informação do utilizador e da rede. A integração de conceitos de dinamismo e de distribuição na gestão da mobilidade, como o ancoramento adaptativo e o suporte dinâmico da mobilidade, permitem a optimização dos recursos da rede e uma melhor experiência por parte do utilizador. Os resultados demonstram, de uma forma geral, que a gestão descentralizada da mobilidade é um caminho promissor, logo este deve ser tomado em consideração pelas operadoras móveis aquando do desenvolvimento das redes do futuro

Game theory for dynamic spectrum sharing cognitive radio

This thesis was submitted for the degree of Doctor of Philosophy and was awarded by Brunel University on 21 June 2010.‘Game Theory’ is the formal study of conflict and cooperation. The theory is based on a set of tools that have been developed in order to assist with the modelling and analysis of individual, independent decision makers. These actions potentially affect any decisions, which are made by other competitors. Therefore, it is well suited and capable of addressing the various issues linked to wireless communications. This work presents a Green Game-Based Hybrid Vertical Handover Model. The model is used for heterogeneous wireless networks, which combines both dynamic (Received Signal Strength and Node Mobility) and static (Cost, Power Consumption and Bandwidth) factors. These factors control the handover decision process; whereby the mechanism successfully eliminates any unnecessary handovers, reduces delay and overall number of handovers to 50% less and 70% less dropped packets and saves 50% more energy in comparison to other mechanisms. A novel Game-Based Multi-Interface Fast-Handover MIPv6 protocol is introduced in this thesis as an extension to the Multi-Interface Fast-handover MIPv6 protocol. The protocol works when the mobile node has more than one wireless interface. The protocol controls the handover decision process by deciding whether a handover is necessary and helps the node to choose the right access point at the right time. In addition, the protocol switches the mobile nodes interfaces ‘ON’ and ‘OFF’ when needed to control the mobile node’s energy consumption and eliminate power lost of adding another interface. The protocol successfully reduces the number of handovers to 70%, 90% less dropped packets, 40% more received packets and acknowledgments and 85% less end-to-end delay in comparison to other Protocols. Furthermore, the thesis adapts a novel combination of both game and auction theory in dynamic resource allocation and price-power-based routing in wireless Ad-Hoc networks. Under auction schemes, destinations nodes bid the information data to access to the data stored in the server node. The server will allocate the data to the winner who values it most. Once the data has been allocated to the winner, another mechanism for dynamic routing is adopted. The routing mechanism is based on the source-destination cooperation, power consumption and source-compensation to the intermediate nodes. The mechanism dramatically increases the seller’s revenue to 50% more when compared to random allocation scheme and briefly evaluates the reliability of predefined route with respect to data prices, source and destination cooperation for different network settings. Last but not least, this thesis adjusts an adaptive competitive second-price pay-to-bid sealed auction game and a reputation-based game. This solves the fairness problems associated with spectrum sharing amongst one primary user and a large number of secondary users in a cognitive radio environment. The proposed games create a competition between the bidders and offers better revenue to the players in terms of fairness to more than 60% in certain scenarios. The proposed game could reach the maximum total profit for both primary and secondary users with better fairness; this is illustrated through numerical results

Concurrent Multipath Transfer: Scheduling, Modelling, and Congestion Window Management

Known as smartphones, multihomed devices like the iPhone and BlackBerry can simultaneously connect to Wi-Fi and 4G LTE networks. Unfortunately, due to the architectural constraints of standard transport layer protocols like the transmission control protocol (TCP), an Internet application (e.g., a file transfer) can use only one access network at a time. Due to recent developments, however, concurrent multipath transfer (CMT) using the stream control transmission protocol (SCTP) can enable multihomed devices to exploit additional network resources for transport layer communications. In this thesis we explore a variety of techniques aimed at CMT and multihomed devices, such as: packet scheduling, transport layer modelling, and resource management. Some of our accomplishments include, but are not limited to: enhanced performance of CMT under delay-based disparity, a tractable framework for modelling the throughput of CMT, a comparison of modelling techniques for SCTP, a new congestion window update policy for CMT, and efficient use of system resources through optimization. Since the demand for a better communications system is always on the horizon, it is our goal to further the research and inspire others to embrace CMT as a viable network architecture; in hopes that someday CMT will become a standard part of smartphone technology

Mobilidade distribuida em ambientes dinâmicos

Mestrado em Engenharia Eletrónica e TelecomunicaçõesConventional networks have implemented a specific hierarchical structure, which in many cases deals with centralized mobility anchoring models to ensure IP session continuity. In this context, mobility management demands the existence of a centralized and static anchor point to allow reachability to mobile nodes connected to distinct networks. However, such centralized element is a single point of failures, introducing longer delays and higher management signalling. It may be more vulnerable to attacks, causing problems in the system. For this reason, mobility management addressed to centralized models is a satisfactory and non-optimal solution when mobile networks become less hierarchical. In order to improve mobility management to meet the requirements in mobile network evolution, there have been proposed solutions to distribute the anchor points closer to the end-user. This way, distributed and dynamic mobility anchoring improves scalability and availability, avoiding single points of failure and bottlenecks, as well as enabling transparent mobility support. In this framework, it is idealized and implemented a set of Vehicular scenarios using two different types of mobility management models, one centralized and another distributed. The results shows that the distributed mobility management protocol provides better results in terms of data loss, average data delay, data cost and signaling cost, when compared with the centralized mobility management protocol. The rapid growth of mobile nodes has lead to the increase of mobile data traffic consumption, and they are currently equipped with multiple network interfaces, which in many cases use different access technologies simultaneously. Therefore, session continuity of a certain user's services should be guaranteed independently of the access network technology. Consequently, there is a fundamental change in the network architectures, which is adopting flatten model to cope with users' behaviour and the evolution of the mobile data traffic consumption. Thus, it is specified a distributed mobility management scheme with multihoming support to provide continuity to active sessions when mobile nodes roam between networks/interfaces. This mobility mechanism is evaluated and tested in a real environment, demonstrating the capability to provide uninterrupted sessions for multihomed scenarios, such as the addition/removal of a link, likewise the capability to improve user experience.As redes de telecomunicações sem fios convencionais têm implementada uma estrutura hierárquica específica que em muitos casos lida com entidades centralizadas para garantirem continuidade de sessão e acessibilidade nas comunicações IP. Neste contexto, a gestão de mobilidade exige que haja uma âncora central e estática para permitir que os nós móveis se encontrem acessíveis quando conectados nas diferentes redes. Porém, este elemento central é suscetível a falhas introduzindo maiores atrasos, exigindo uma maior gestão da sinalização, sendo mais vulnerável a ataques o que pode causar problemas no sistema. Por estas razões, à medida que as redes móveis se tornam cada vez menos hierárquicas, a gestão da mobilidade baseada em modelos centralizados torna-se menos otimizada. Para melhorar a gestão de mobilidade tendo em consideração as exigências evolutivas da rede, têm vindo a ser propostas soluções para distribuir as âncoras, colocando-as mais perto do utilizador final com o objetivo de tornar a rede menos hierárquica, descentralizando o processo de gestão de mobilidade de uma forma dinâmica pelos nós da rede. Desta forma, a mobilidade distribuída em ambientes dinâmicos melhora a escalabilidade, acessibilidade e evita pontos centrais de falhas e engarrafamentos. Neste contexto, são idealizados e implementados três cenários de redes veiculares usando dois modelos de gestão de mobilidade, um centralizado e outro distribuído. Os resultados mostram que o protocolo de gestão de mobilidade distribuído apresenta melhores resultados em termos de perda de pacotes, atraso médio por pacote, custo de dados e custo de sinalização quando comparado com o protocolo de gestão de mobilidade centralizado. O rápido crescimento de nós móveis tem levado ao aumento do consumo de trafego de dados e, atualmente, estes estão equipados com múltiplas interfaces que, em muitos casos, utilizam diferentes tecnologias de acesso à rede. No entanto, a continuidade de sessão de um determinado serviço deve ser garantido, independentemente da tecnologia de acesso utilizada. Consequentemente, há uma preocupação em transformar a arquitetura da rede em modelos menos hierárquicos para lidar com o comportamento dos utilizadores e com a evolução do consumo de tráfego de dados móveis. Desta forma, é especificado um esquema de gestão de mobilidade distribuída com suporte a múltiplas interfaces para manter continuidade de sessões quando os nós móveis mudam de rede ou interface. Este mecanismo de mobilidade foi avaliado e testado num cenário real, demonstrando a capacidade de manter as sessões ativas em cenários com múltiplas interfaces melhorando a experiência do utilizador, dando como exemplo cenários de perda de ligação, ligação a outras redes e ligar/desligar uma interface