48 research outputs found
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Heterogeneous Access: Survey and Design Considerations
As voice, multimedia, and data services are converging to IP, there is a need for a new networking architecture to support future innovations and applications. Users are consuming Internet services from multiple devices that have multiple network interfaces such as Wi-Fi, LTE, Bluetooth, and possibly wired LAN. Such diverse network connectivity can be used to increase both reliability and performance by running applications over multiple links, sequentially for seamless user experience, or in parallel for bandwidth and performance enhancements. The existing networking stack, however, offers almost no support for intelligently exploiting such network, device, and location diversity. In this work, we survey recently proposed protocols and architectures that enable heterogeneous networking support. Upon evaluation, we abstract common design patterns and propose a unified networking architecture that makes better use of a heterogeneous dynamic environment, both in terms of networks and devices. The architecture enables mobile nodes to make intelligent decisions about how and when to use each or a combination of networks, based on access policies. With this new architecture, we envision a shift from current applications, which support a single network, location, and device at a time to applications that can support multiple networks, multiple locations, and multiple devices
SCALABLE AND EFFICIENT VERTICAL HANDOVER DECISION ALGORITHMS IN VEHICULAR NETWORK CONTEXTS
A finales de los años noventa, y al comienzo del nuevo milenio, las redes inalámbricas han evolucionado bastante, pasando de ser sólo una tecnología prometedora para convertirse en un requisito para las actividades cotidianas en las sociedades desarrolladas. La infraestructura de transporte también ha evolucionado, ofreciendo comunicación a bordo para mejorar la seguridad vial y el acceso a contenidos de información y entretenimiento.
Los requisitos de los usuarios finales se han hecho dependientes de la tecnología, lo que significa que sus necesidades de conectividad han aumentado debido a los diversos requisitos de las aplicaciones que se ejecutan en sus dispositivos móviles, tales como tabletas, teléfonos inteligentes, ordenadores portátiles o incluso ordenadores de abordo (On-Board Units (OBUs)) dentro de los vehículos. Para cumplir con dichos requisitos de conectividad, y teniendo en cuenta las diferentes redes inalámbricas disponibles, es necesario adoptar técnicas de Vertical Handover (VHO) para cambiar de red de forma transparente y sin necesidad de intervención del usuario.
El objetivo de esta tesis es desarrollar algoritmos de decisión (Vertical Handover Decision Algorithms (VHDAs)) eficientes y escalables, optimizados para el contexto de las redes vehiculares. En ese sentido se ha propuesto, desarrollado y probado diferentes algoritmos de decisión basados en la infraestructura disponible en las actuales, y probablemente en las futuras, redes inalámbricas y redes vehiculares. Para ello se han combinado diferentes técnicas, métodos computacionales y modelos matemáticos, con el fin de garantizar una conectividad apropiada, y realizando el handover hacia las redes más adecuadas de manera a cumplir tanto con los requisitos de los usuarios como los requisitos de las aplicaciones.
Con el fin de evaluar el contexto, se han utilizado diferentes herramientas para obtener información variada, como la disponibilidad de la red, el estado de la red, la geolocalizaciónMárquez Barja, JM. (2012). SCALABLE AND EFFICIENT VERTICAL HANDOVER DECISION ALGORITHMS IN VEHICULAR NETWORK CONTEXTS [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/17869Palanci
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Integration of unidirectional technologies into wireless back-haul architecture
This thesis was submitted for the degree of Docter of Philosophy and awarded by Brunel University.Back-haul infrastructures of today's wireless operators must support the triple-play services demanded by the market or regulatory bodies. To cope with increasing capacity demand, the EU FP7 project CARMEN has developed a cost-effective heterogeneous
multi-radio wireless back-haul architecture, which may also leverage the native multicast
capabilities of broadcast technologies such as DVB-T to off-load high-bandwidth broadcast
content delivery. However, the integration of such unidirectional technologies into a packet-switched architecture requires careful considerations. The contribution of this thesis is the investigation, design and evaluation of protocols and mechanisms facilitating the integration of such unidirectional technologies into the wireless
back-haul architecture so that they can be configured and utilized by the spectrum and
capacity optimization modules. This integration mainly concerns the control plane and, in particular, the aspects related to resource and capability descriptions, neighborhood, link and Multi Protocol Label Switching (MPLS) Label-Switched Path (LSP) monitoring, unicast and multicast LSP signalling as well as topology forming and maintenance. During the course of this study we have analyzed the problem space, proposed solutions to the resulting research questions and evaluated our approach. Our results show that the now Unidirectional Technology (UDT)-aware architecture can readily consider
Unidirectional Technologies (UDTs) to distribute, for example, broadcast content
Lightweight mobile and wireless systems: technologies, architectures, and services
1Department of Information and Communication Systems Engineering (ICSE), University of the Aegean, 81100 Mytilene, Greece 2Department of Information Engineering and Computer Science (DISI), University of Trento, 38123 Trento, Italy 3Department of Informatics, Alexander Technological Educational Institute of Thessaloniki, Thessaloniki, 574 00 Macedonia, Greece 4Centre Tecnologic de Telecomunicacions de Catalunya (CTTC), 08860 Barcelona, Spain 5North Carolina State University (NCSU), Raleigh, NC 27695, US
Access Network Selection in a 4G Networking Environment
An all-IP pervasive networking system provides a comprehensive IP solution where voice, data and streamed multimedia can be delivered to users at anytime and anywhere. Network selection is a key issue in this converged heterogeneous networking environment. A traditional way to select a target network is only based on the received signal strength (RSS); however, it is not comprehensive enough to meet the various demands of different multimedia applications and different users. Though some existing schemes have considered multiple criteria (e.g. QoS, security, connection cost, etc.) for access network selection, there are still several problems unsettled or not being solved perfectly. In this thesis, we propose a novel model to handle this network selection issue. Firstly, we take advantage of IEEE 802.21 to obtain the information of neighboring networks and then classify the information into two categories: 1) compensatory information and 2) non-compensatory information; secondly, we use the non-compensatory information to sort out the capable networks as candidates. If a neighboring network satisfies all the requirements of non-compensatory criteria, the checking of the compensatory information will then be triggered; thirdly, taking the values of compensatory information as input, we propose a hybrid ANP and RTOPSIS model to rank the candidate networks. ANP elicit weights to compensatory criteria and eliminates the interdependence impact on them, and RTOPSIS resolves the rank reversal problem which happens in some multiple criteria decision making (MCDM) algorithms such as AHP, TOPSIS, and ELECTRE. The evaluation study verifies the usability and validity of our proposed network selection method. Furthermore, a comparison study with a TOPSIS based algorithm shows the advantage and superiority of the proposed RTOPSIS based model
Middleware de comunicações para a internet móvel futura
Doutoramento em Informática (MAP-I)A evolução constante em novas tecnologias que providenciam suporte à forma como os nossos dispositivos se ligam, bem como a forma como utilizamos diferentes capacidades e serviços on-line, criou um conjunto sem precedentes de novos desafios que motivam o desenvolvimento de uma recente área de investigação, denominada de Internet Futura. Nesta nova área de investigação, novos aspectos arquiteturais estão ser desenvolvidos, os quais, através da re-estruturação de componentes nucleares subjacentesa que compõem a Internet, progride-a de uma forma capaz de não são fazer face a estes novos desafios, mas também de a preparar para os desafios de amanhã. Aspectos chave pertencendo a este conjunto de desafios são os ambientes de rede heterogéneos compostos por diferentes tipos de redes de acesso, a cada vez maior mudança do tráfego peer-to-peer (P2P) como o tipo de tráfego mais utilizado na Internet, a orquestração de cenários da Internet das Coisas (IoT) que exploram mecanismos de interação Maquinaa-Maquina (M2M), e a utilização de mechanismos centrados na informação
(ICN). Esta tese apresenta uma nova arquitetura capaz de simultaneamente
fazer face a estes desafios, evoluindo os procedimentos de conectividade e
entidades envolvidas, através da adição de uma camada de middleware, que
age como um mecanismo de gestão de controlo avançado. Este mecanismo
de gestão de controlo aproxima as entidades de alto nível (tais como
serviços, aplicações, entidades de gestão de mobilidade, operações de encaminhamento, etc.) com as componentes das camadas de baixo nível
(por exemplo, camadas de ligação, sensores e atuadores), permitindo uma
otimização conjunta dos procedimentos de ligação subjacentes. Os resultados
obtidos não só sublinham a flexibilidade dos mecanismos que compoem
a arquitetura, mas também a sua capacidade de providenciar aumentos de
performance quando comparados com outras soluÇÕes de funcionamento
especÍfico, enquanto permite um maior leque de cenáios e aplicações.The constant evolution in new technologies that support the way our devices
are able to connect, as well the way we use available on-line services and capabilities, has created a set of unprecedented new challenges that motivated
the development of a recent research trend known as the Future Internet.
In this research trend, new architectural aspects are being developed which,
through the restructure of underlying core aspects composing the Internet,
reshapes it in a way capable of not only facing these new challenges,
but also preparing it to tackle tomorrow’s new set of complex issues. Key
aspects belonging to this set of challenges are heterogeneous networking
environments composed by di↵erent kinds of wireless access networks, the
evergrowing change from peer-to-peer (P2P) to video as the most used kind
of traffic in the Internet, the orchestration of Internet of Things (IoT) scenarios exploiting Machine-to-Machine (M2M) interactions, and the usage of
Information-Centric Networking (ICN). This thesis presents a novel framework
able to simultaneous tackle these challenges, empowering connectivity
procedures and entities with a middleware acting as an advanced control
management mechanism. This control management mechanism brings together
both high-level entities (such as application services, mobility management
entities, routing operations, etc.) with the lower layer components
(e.g., link layers, sensor devices, actuators), allowing for a joint optimization of the underlying connectivity and operational procedures. Results highlight not only the flexibility of the mechanisms composing the framework, but also their ability in providing performance increases when compared with other specific purpose solutions, while allowing a wider range of scenarios and deployment possibilities
Distribuição de vídeo para grupos de utilizadores em redes móveis heterogéneas19
The evolutions veri ed in mobile devices capabilities (storage capacity, screen
resolution, processor, etc.) over the last years led to a signi cant change
in mobile user behavior, with the consumption and creation of multimedia
content becoming more common, in particular video tra c. Consequently,
mobile operator networks, despite being the target of architectural evolutions
and improvements over several parameters (such as capacity, transmission
and reception performance, amongst others), also increasingly become more
frequently challenged by performance aspects associated to the nature of
video tra c, whether by the demanding requirements associated to that
service, or by its volume increase in such networks.
This Thesis proposes modi cations to the mobile architecture towards a more
e cient video broadcasting, de ning and developing mechanisms applicable
to the network, or to the mobile terminal. Particularly, heterogeneous
networks multicast IP mobility supported scenarios are focused, emphasizing
their application over di erent access technologies. The suggested changes
are applicable to mobile or static user scenarios, whether it performs the role
of receiver or source of the video tra c. Similarly, the de ned mechanisms
propose solutions targeting operators with di erent video broadcasting goals,
or whose networks have di erent characteristics. The pursued methodology
combined an experimental evaluation executed over physical testbeds,
with the mathematical evaluation using network simulation, allowing the
veri cation of its impact on the optimization of video reception in mobile
terminalsA evolução veri cada nas características dos dispositivos moveis (capacidade
de armazenamento, resolução do ecrã, processador, etc.) durante os
últimos anos levou a uma alteração signi cativa nos comportamentos dos
utilizadores, sendo agora comum o consumo e produção de conteúdos
multimédia envolvendo terminais móveis, em particular o tráfego vídeo.
Consequentemente, as redes de operador móvel, embora tendo também sido
alvo constante de evoluções arquitecturais e melhorias em vários parâmetros
(tais como capacidade, ritmo de transmissão/recepção, entre outros), vêemse
cada vez mais frequentemente desa adas por aspectos de desempenho
associados à natureza do tráfego de vídeo, seja pela exigência de requisitos
associados a esse serviço, quer pelo aumento do volume do mesmo nesse
tipo de redes.
Esta Tese propôe alterações à arquitetura móvel para a disseminação de vídeo
mais e ciente, de nindo e desenvolvendo mecanismos aplicáveis à rede, ou
ao utilizador móvel. Em particular, são focados cenários suportados por IP
multicast em redes móveis heterogéneas, isto é, com ênfase na aplicação
destes mecanismos sobre diferentes tecnologias de acesso. As alterações
sugeridas aplicam-se a cenários de utilizador estático ou móvel, sendo este a
fonte ou receptor do tráfego vídeo. Da mesma forma, são propostas soluções
tendo em vista operadores com diferentes objectivos de disseminação de
vídeo, ou cujas redes têm diferentes características. A metodologia utilizada
combinou a avaliação experimental em testbeds físicas com a avaliação
matemática em simulações de redes, e permitiu veri car o impacto sobre
a optimização da recepção de vídeo em terminais móveisPrograma Doutoral em Telecomunicaçõe
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
Quality of service differentiation for multimedia delivery in wireless LANs
Delivering multimedia content to heterogeneous devices over a variable networking environment while maintaining high quality levels involves many technical challenges. The research reported in this thesis presents a solution for Quality of Service (QoS)-based service differentiation when delivering multimedia content over the wireless LANs. This thesis has three major contributions outlined below:
1. A Model-based Bandwidth Estimation algorithm (MBE), which estimates the available bandwidth based on novel TCP and UDP throughput models over IEEE 802.11 WLANs. MBE has been modelled, implemented, and tested through simulations and real life testing. In comparison with other bandwidth estimation techniques, MBE shows better performance in terms of error rate, overhead, and loss.
2. An intelligent Prioritized Adaptive Scheme (iPAS), which provides QoS service differentiation for multimedia delivery in wireless networks. iPAS assigns dynamic priorities to various streams and determines their bandwidth share by employing a probabilistic approach-which makes use of stereotypes. The total bandwidth to be allocated is estimated using MBE. The priority level of individual stream is variable and dependent on stream-related characteristics and delivery QoS parameters. iPAS can be deployed seamlessly over the original IEEE 802.11 protocols and can be included in the IEEE 802.21 framework in order to optimize the control signal communication. iPAS has been modelled, implemented, and evaluated via simulations. The results demonstrate that iPAS achieves better performance than the equal channel access mechanism over IEEE 802.11 DCF and a service differentiation scheme on top of IEEE 802.11e EDCA, in terms of fairness, throughput, delay, loss, and estimated PSNR. Additionally, both objective and subjective video quality assessment have been performed using a prototype system.
3. A QoS-based Downlink/Uplink Fairness Scheme, which uses the stereotypes-based structure to balance the QoS parameters (i.e. throughput, delay, and loss) between downlink and uplink VoIP traffic. The proposed scheme has been modelled and tested through simulations. The results show that, in comparison with other downlink/uplink fairness-oriented solutions, the proposed scheme performs better in terms of VoIP capacity and fairness level between downlink and uplink traffic
Network selection mechanism for telecardiology application in high speed environment
The existing network selection schemes biased either to cost or Quality of Service (QoS) are not efficient enough for telecardiology application in high traveling speed environment. Selection of the candidate network that is fulfilling the telecardiology service requirements as well as user preference is a challenging issue. This is because the preference of telecardiology user might change based on the patient health condition. This research proposed a novel Telecardiology-based Handover Decision Making (THODM) mechanism that consists of three closely integrated algorithms: Adaptive Service Adjustment (ASA), Dwelling Time Prediction (DTP) and Patient Health Condition-based Network Evaluation (PHCNE). The ASA algorithm guarantees the quality of telecardiology service when none of the available networks fulfils the service requirements. The DTP algorithm minimizes the probability of handover failure and unnecessary handover to Wireless Local Area Network (WLAN), while optimizing the connection time with WLAN in high traveling speed environment. The PHCNE algorithm evaluates the quality of available networks and selects the best network based on the telecardiology services requirement and the patient health condition. Simulation results show that the proposed THODM mechanism reduced the number of handover failures and unnecessary handovers up to 80.0% and 97.7%, respectively, compared with existing works. The cost of THODM mechanism is 20% and 85.3% lower than the Speed Threshold-based Handover (STHO) and Bandwidth-based Handover (BWHO) schemes, respectively. In terms of throughput, the proposed scheme is up to 75% higher than the STHO scheme and 370% greater than the BWHO scheme. For telecardiology application in high traveling speed environment, the proposed THODM mechanism has better performance than the existing network selection schemes