998 research outputs found
Acesso banda larga sem fios em ambientes heterogéneos de próxima geração
Doutoramento em Engenharia InformáticaO acesso ubíquo à Internet é um dos principais desafios para os operadores
de telecomunicações na próxima década. O número de utilizadores da Internet
está a crescer exponencialmente e o paradigma de acesso "always connected,
anytime, anywhere" é um requisito fundamental para as redes móveis de
próxima geração. A tecnologia WiMAX, juntamente com o LTE, foi
recentemente reconhecida pelo ITU como uma das tecnologias de acesso
compatíveis com os requisitos do 4G. Ainda assim, esta tecnologia de acesso
não está completamente preparada para ambientes de próxima geração,
principalmente devido à falta de mecanismos de cross-layer para integração de
QoS e mobilidade. Adicionalmente, para além das tecnologias WiMAX e LTE,
as tecnologias de acesso rádio UMTS/HSPA e Wi-Fi continuarão a ter um
impacto significativo nas comunicações móveis durante os próximos anos.
Deste modo, é fundamental garantir a coexistência das várias tecnologias de
acesso rádio em termos de QoS e mobilidade, permitindo assim a entrega de
serviços multimédia de tempo real em redes móveis.
Para garantir a entrega de serviços multimédia a utilizadores WiMAX, esta
Tese propõe um gestor cross-layer WiMAX integrado com uma arquitectura de
QoS fim-a-fim. A arquitectura apresentada permite o controlo de QoS e a
comunicação bidireccional entre o sistema WiMAX e as entidades das
camadas superiores. Para além disso, o gestor de cross-layer proposto é
estendido com eventos e comandos genéricos e independentes da tecnologia
para optimizar os procedimentos de mobilidade em ambientes WiMAX. Foram
realizados testes para avaliar o desempenho dos procedimentos de QoS e
mobilidade da arquitectura WiMAX definida, demonstrando que esta é
perfeitamente capaz de entregar serviços de tempo real sem introduzir custos
excessivos na rede.
No seguimento das extensões de QoS e mobilidade apresentadas para a
tecnologia WiMAX, o âmbito desta Tese foi alargado para ambientes de
acesso sem-fios heterogéneos. Neste sentido, é proposta uma arquitectura de
mobilidade transparente com suporte de QoS para redes de acesso multitecnologia.
A arquitectura apresentada integra uma versão estendida do IEEE
802.21 com suporte de QoS, bem como um gestor de mobilidade avançado
integrado com os protocolos de gestão de mobilidade do nível IP. Finalmente,
para completar o trabalho desenvolvido no âmbito desta Tese, é proposta uma
extensão aos procedimentos de decisão de mobilidade em ambientes
heterogéneos para incorporar a informação de contexto da rede e do terminal.
Para validar e avaliar as optimizações propostas, foram desenvolvidos testes
de desempenho num demonstrador inter-tecnologia, composta pelas redes de
acesso WiMAX, Wi-Fi e UMTS/HSPA.Ubiquitous Internet access is one of the main challenges for the
telecommunications industry in the next decade. The number of users
accessing the Internet is growing exponentially and the network access
paradigm of “always connected, anytime, anywhere” is a central requirement
for the so-called Next Generation Mobile Networks (NGMN). WiMAX, together
with LTE, was recently recognized by ITU as one of the compliant access
technologies for 4G. Nevertheless, WiMAX is not yet fully prepared for next
generation environments, mainly due to the lack of QoS and mobility crosslayer
procedures to support real-time multimedia services delivery.
Furthermore, besides the 4G compliant WiMAX and LTE radio access
technologies, UMTS/HSPA and Wi-Fi will also have a significant impact in the
mobile communications during the next years. Therefore, it is fundamental to
ensure the coexistence of multiple radio access technologies in what QoS and
mobility procedures are concerned, thereby allowing the delivery of real-time
services in mobile networks.
In order to provide the WiMAX mobile users with the demanded multimedia
services, it is proposed in this Thesis a WiMAX cross-layer manager integrated
in an end-to-end all-IP QoS enabled architecture. The presented framework
enables the QoS control and bidirectional communication between WiMAX and
the upper layer network entities. Furthermore, the proposed cross-layer
framework is extended with media independent events and commands to
optimize the mobility procedures in WiMAX environments. Tests were made to
evaluate the QoS and mobility performance of the defined architecture,
demonstrating that it is perfectly capable of handling and supporting real time
services without introducing an excessive cost in the network.
Following the QoS and mobility extensions provided for WiMAX, the scope of
this Thesis is broaden and a seamless mobility architecture with QoS support in
heterogeneous wireless access environments is proposed. The presented
architecture integrates an extended version of the IEEE 802.21 framework with
QoS support, as well as an advanced mobility manager integrated with the IP
level mobility management protocols. Finally, to complete the work within the
framework of this Thesis, it is proposed an extension to the handover decisionmaking
processes in heterogeneous access environments through the
integration of context information from both the network entities and the enduser.
Performance tests were developed in a real testbed to validate the
proposed optimizations in an inter-technology handover scenario involving
WiMAX, Wi-Fi and UMTS/HSPA
Will SDN be part of 5G?
For many, this is no longer a valid question and the case is considered
settled with SDN/NFV (Software Defined Networking/Network Function
Virtualization) providing the inevitable innovation enablers solving many
outstanding management issues regarding 5G. However, given the monumental task
of softwarization of radio access network (RAN) while 5G is just around the
corner and some companies have started unveiling their 5G equipment already,
the concern is very realistic that we may only see some point solutions
involving SDN technology instead of a fully SDN-enabled RAN. This survey paper
identifies all important obstacles in the way and looks at the state of the art
of the relevant solutions. This survey is different from the previous surveys
on SDN-based RAN as it focuses on the salient problems and discusses solutions
proposed within and outside SDN literature. Our main focus is on fronthaul,
backward compatibility, supposedly disruptive nature of SDN deployment,
business cases and monetization of SDN related upgrades, latency of general
purpose processors (GPP), and additional security vulnerabilities,
softwarization brings along to the RAN. We have also provided a summary of the
architectural developments in SDN-based RAN landscape as not all work can be
covered under the focused issues. This paper provides a comprehensive survey on
the state of the art of SDN-based RAN and clearly points out the gaps in the
technology.Comment: 33 pages, 10 figure
Employing Unmanned Aerial Vehicles for Improving Handoff using Cooperative Game Theory
Heterogeneous wireless networks that are used for seamless mobility are expected to face prominent problems in future 5G cellular networks. Due to their proper flexibility and adaptable preparation, remote-controlled Unmanned Aerial Vehicles (UAVs) could assist heterogeneous wireless communication. However, the key challenges of current UAV-assisted communications consist in having appropriate accessibility over wireless networks via mobile devices with an acceptable Quality of Service (QoS) grounded on the users' preferences. To this end, we propose a novel method based on cooperative game theory to select the best UAV during handover process and optimize handover among UAVs by decreasing the (i) end-to-end delay, (ii) handover latency and (iii) signaling overheads. Moreover, the standard design of Software Defined Network (SDN) with Media Independent Handover (MIH) is used as forwarding switches in order to obtain seamless mobility. Numerical results derived from the real data are provided to illustrate the effectiveness of the proposed approach in terms of number of handovers, cost and delay
Recent Advances in Wireless Communications and Networks
This book focuses on the current hottest issues from the lowest layers to the upper layers of wireless communication networks and provides "real-time" research progress on these issues. The authors have made every effort to systematically organize the information on these topics to make it easily accessible to readers of any level. This book also maintains the balance between current research results and their theoretical support. In this book, a variety of novel techniques in wireless communications and networks are investigated. The authors attempt to present these topics in detail. Insightful and reader-friendly descriptions are presented to nourish readers of any level, from practicing and knowledgeable communication engineers to beginning or professional researchers. All interested readers can easily find noteworthy materials in much greater detail than in previous publications and in the references cited in these chapters
6G White Paper on Edge Intelligence
In this white paper we provide a vision for 6G Edge Intelligence. Moving towards 5G and beyond the future 6G networks, intelligent solutions utilizing data-driven machine learning and artificial intelligence become crucial for several real-world applications including but not limited to, more efficient manufacturing, novel personal smart device environments and experiences, urban computing and autonomous traffic settings. We present edge computing along with other 6G enablers as a key component to establish the future 2030 intelligent Internet technologies as shown in this series of 6G White Papers. In this white paper, we focus in the domains of edge computing infrastructure and platforms, data and edge network management, software development for edge, and real-time and distributed training of ML/AI algorithms, along with security, privacy, pricing, and end-user aspects. We discuss the key enablers and challenges and identify the key research questions for the development of the Intelligent Edge services. As a main outcome of this white paper, we envision a transition from Internet of Things to Intelligent Internet of Intelligent Things and provide a roadmap for development of 6G Intelligent Edge
Ubiquitous robust communications for emergency response using multi-operator heterogeneous networks
A number of disasters in various places of the planet have caused an extensive loss of lives, severe damages to properties and the environment, as well as a tremendous shock to the survivors. For relief and mitigation operations, emergency responders are immediately dispatched to the disaster areas. Ubiquitous and robust communications during the emergency response operations are of paramount importance. Nevertheless, various reports have highlighted that after many devastating events, the current technologies used, failed to support the mission critical communications, resulting in further loss of lives. Inefficiencies of the current communications used for emergency response include lack of technology inter-operability between different jurisdictions, and high vulnerability due to their centralized infrastructure. In this article, we propose a flexible network architecture that provides a common networking platform for heterogeneous multi-operator networks, for interoperation in case of emergencies. A wireless mesh network is the main part of the proposed architecture and this provides a back-up network in case of emergencies. We first describe the shortcomings and limitations of the current technologies, and then we address issues related to the applications and functionalities a future emergency response network should support. Furthermore, we describe the necessary requirements for a flexible, secure, robust, and QoS-aware emergency response multi-operator architecture, and then we suggest several schemes that can be adopted by our proposed architecture to meet those requirements. In addition, we suggest several methods for the re-tasking of communication means owned by independent individuals to provide support during emergencies. In order to investigate the feasibility of multimedia transmission over a wireless mesh network, we measured the performance of a video streaming application in a real wireless metropolitan multi-radio mesh network, showing that the mesh network can meet the requirements for high quality video transmissions
Interoperabilidade e mobilidade na internet do futuro
Research on Future Internet has been gaining traction in recent years,
with both evolutionary (e.g., Software Defined Networking (SDN)-
based architectures) and clean-slate network architectures (e.g., Information
Centric Networking (ICN) architectures) being proposed. With
each network architectural proposal aiming to provide better solutions
for specific Internet utilization requirements, an heterogeneous Future
Internet composed by several architectures can be expected, each targeting
and optimizing different use case scenarios. Moreover, the increasing
number of mobile devices, with increasing capabilities and
supporting different connectivity technologies, are changing the patterns
of traffic exchanged in the Internet.
As such, this thesis focuses on the study of interoperability and mobility
in Future Internet architectures, two key requirements that need to be
addressed for the widely adoption of these network architectures. The
first contribution of this thesis is an interoperability framework that,
by enabling resources to be shared among different network architectures,
avoids resources to be restricted to a given network architecture
and, at the same time, promotes the initial roll out of new network
architectures. The second contribution of this thesis consists on the
development of enhancements for SDN-based and ICN network architectures
through IEEE 802.21 mechanisms to facilitate and optimize
the handover procedures on those architectures. The last contribution
of this thesis is the definition of an inter-network architecture mobility
framework that enables MNs to move across access network supporting
different network architectures without losing the reachability to
resources being accessed. All the proposed solutions were evaluated
with results highlighting the feasibility of such solutions and the impact
on the overall communication.A Internet do Futuro tem sido alvo de vários estudos nos últimos anos,
com a proposta de arquitecturas de rede seguindo quer abordagens
evolutionárias (por exemplo, Redes Definidas por Software (SDN))
quer abordagens disruptivas (por exemplo, Redes Centradas na Informação (ICN)). Cada uma destas arquitecturas de rede visa providenciar
melhores soluções relativamente a determinados requisitos de
utilização da Internet e, portanto, uma Internet do Futuro heterogénea
composta por diversas arquitecturas de rede torna-se uma possibilidade,
onde cada uma delas é usada para optimizar diferentes casos
de utilização. Para além disso, o aumento do número de dispositivos
móveis, com especificações acrescidas e com suporte para diferentes
tecnologias de conectividade, está a mudar os padrões do tráfego na
Internet.
Assim, esta tese foca-se no estudo de aspectos de interoperabilidade e
mobilidade em arquitecturas de rede da Internet do Futuro, dois importantes
requisitos que necessitam de ser satisfeitos para que a adopção
destas arquitecturas de rede seja considerada. A primeira contribuição
desta tese é uma solução de interoperabilidade que, uma vez que permite
que recursos possam ser partilhados por diferentes arquitecturas
de rede, evita que os recursos estejam restringidos a uma determinada
arquitectura de rede e, ao mesmo tempo, promove a adopção de novas
arquitecturas de rede. A segunda contribuição desta tese consiste
no desenvolvimento de extensões para arquitecturas de rede baseadas
em SDN ou ICN através dos mecanismos propostos na norma IEEE
802.21 com o objectivo de facilitar e optimizar os processos de mobilidade
nessas arquitecturas de rede. Finalmente, a terceira contribuição
desta tese é a definição de uma solução de mobilidade envolvendo diferentes
arquitecturas de rede que permite a mobilidade de dispositivos
móveis entre redes de acesso que suportam diferentes arquitecturas de
rede sem que estes percam o acesso aos recursos que estão a ser acedidos.
Todas as soluções propostas foram avaliadas com os resultados
a demonstrar a viabilidade de cada uma das soluções e o impacto que
têm na comunicação.Programa Doutoral em Informátic
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