94 research outputs found
Service Delivery Utilizing Wireless Technology Within The Air Traffic Control Communication And Navigation Domain To Improve Positioning Awareness
Current air traffic levels around the world have pushed the enterprise architecture deployed to support air traffic management to the breaking point. Technology limitations prevent expansion of the current solutions to handle rising utilization levels without adopting radically different information delivery approaches. Meanwhile, an architectural transition would present the opportunity to support business and safety requirements that are not currently addressable. The purpose of this research paper is to create a framework for more effectively sharing positioning information utilizing improved air traffic control navigation and communication systems
Media independent handovers : network selection for mobile IP nodes in heterogeneous wireless networks
Includes abstract.Includes bibliographical references (p. 79-82).In Next Generation Networks (NGN), also known as 4G, Beyond 3G, Converged, Integrated and Interworked Network, user node mobility in wireless and wired environments will seamlessly cross disparate network boundaries. The effort to offer ubiquitous computing, providing access to services anywhere and anytime, strongly encourages the ability to roam across the different existing and future networks. Literature shows investigation of concepts such as Always Best Connected (ABC) when heterogeneous networks co-exist , which will work or compete with other schemes like Home Network Default (HND), Compatibility and Network Operator Agreements (CNOA) to guide network selection or access . With the variety of available networks, the mobile node may be faced with having to decide which network to connect to. We concentrate on the network selection aspects of these envisaged mobile, overlay and integrated environment in heterogeneous networks. The standard developments by the IEEE802.21 Working group and the IETF Networking group form the base of our approach that seeks to see mobility across heterogeneous networks a reality. We propose an IEEE802.21 Media Independent Handover Function (MIHF) based network discovery and network selection, leading to a handover. The selection may be further assisted by an MIHF capable Broker Node that is Third party to the Network Providers to provide a central yet distributed database of the available networks as encountered by the Mobile Node, to cater for Nodes with no prior knowledge of networks and software repository. A Mobile Node (MN) in our solution uses 802.21 communication messages to obtain information about foreign networks encountered before selecting the networks to connect to. Our evaluation through simulations, shows that network selection in heterogeneous wireless networks environment for the appropriately equipped devices is greatly enhanced by the use of the Media Independent Handover Protocol. In scenarios where the mobile node has no prior knowledge of the encountered different network architectures, the use of a Broker node can, for an optimal number of available networks also greatly enhance the mobile node’s network selection by reducing the delay associated and the packet losses incurred
Heterogeneous networks using mobile-IP technology
Whenever a mobile user moves between networks a handover must occur. This basically means that a network-layer protocol must handle the moving of the mobile device. In a cellular phone a GSM/UMTS infrastructure performs horizontal handover and the user does not notices any call or ongoing session interruption while roaming. The handover procedure begins when the received signal strength identificator (RSSI) of a mobile device falls below a level, it discovers a neighbour access point with better quality of services (QoS) than its current access point. In heterogeneous wireless networks different portions of RF spectrum are used and is difficult or impossible for a mobile node to concurrently maintain its connectivity without signal interruptions. Thus, the different network environments must be integrated and support a common platform to achieve seamless handover. The seamless or vertical handover's target is to maintain the mobile user's IP address independently of user's location or of the physical parameters the current network is using. A mechanism that keeps a mobile device to an ongoing connection by maintaining its home-location IP address is the Mobile-IP protocol which operates at the network-layer of the Open System Interconnection (OSI) model.
In this M.Sc. thesis we perform heterogeneous network scenarios with the Mobile-IP technology. Moreover, we have built the system practically and assist the applicability of such heterogeneous wireless networks through real-side measurements. We used Linux operating system (Ubuntu & Debian) between different network technologies, made at the National Center for Scientific Research (NCSR) ''Demokritos'' institute, in Greece. The required applications for the Mobile-IP and 3G technologies were implemented and configured in a platform of fixed and mobile devices at Demokrito's departmental laboratory. The idea of using the Mobile-IP protocol was to gather information about time differences that occurred in handover delay between different networks.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format
Soft Handover scheme for WSN nodes using media independent handover functions
The present wireless networks are equipped with multiple radio links and operate in a collaborative way to enable continuous data transfer even when any link goes down. The IEEE 802.21 is a standard to provide continuous wireless connectivity between heterogeneous link technologies using media independent handover functions as MIHF. The standard supports handover between IEEE 802.11, IEEE 802.16, 3GPP cellular networks. The wireless sensor networks (WSN) based on IEEE 802.15.4 consists of sensors to monitor various physical or physiological activities and to transfer the collected data to the remote controlling station using a short range radio. But in this case if the wireless node moves out of each other's communication range data transfer is not possible. So in this paper, the WSN communication protocol is made as a part of the IEEE 802.21 stack to explore the handover feature offered by the standard. The proposed stack has an internal partition to make WSN protocol to operate independently with other similar modules as long as they are in range, and the MIH function gets triggered by the application when the home networks are not available thus to provide handover from other link interfaces. The proposed hardware has IEEE 802.11, IEEE 802.16, and 3GPP links which are operated by the MIH functions along with the IEEE 802.15.4 interface. So the WSN modules are provisioned to have connectivity from multiple radio interfaces even if they move out of the coverage range from the current point of access. The proposed primitives for handover between WSN and other links are efficient in providing reliable handoff. Keywords: IEEE 802.21, Media independent handover, IEEE 802.15.4, Wireless sensor network
Towards a GNU/Linux IEEE 802.21 Implementation
Abstract-Multiaccess mobile devices and overlapping wireless network deployments have emerged as a next generation network fixture. To make the most of all available networks, mobile devices should be capable of handing over between heterogeneous networks seamlessly and automatically. At the same time, operators should be able to steer network attachment based on their criteria. Although several cross layer mechanisms have been proposed in recent years, only the Media Independent Handover (MIH) Services framework has advanced in any of the established standardization bodies. This paper presents a blueprint for a GNU/Linux implementation of IEEE 802.21. We review the salient points of the standard, introduce our software implementation architecture, detail information gathering in GNU/Linux, and show how our prototype implementation can be used in practice. In contrast with prior published work, this paper presents a real IEEE 802.21 implementation, not an abstracted or reduced MIH-like framework, tested and empirically evaluated over real heterogeneous networks
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
Network-Assisted Handover for Heterogeneous Wireless Networks using IEEE 802.21
The IEEE 802.21 is a standard for enabling handover in heterogeneous wireless networks. Published in January 2009, it defines protocols and messages for mobile-to-node and node-to-node communication in a technology-neutral and flexible manner. The need arises because of the widespread diffusion of different technologies for wireless communications (e.g., WiFi, WiMAX, LTE) coexisting in the same geographical area. Even though the number of multi-radio multi-technology mobile devices is increasing significantly, there are no open solutions in the market to enable efficient inter-technology handover.
As is often the case with communication standards, the structure of the required components, the procedures, and the algorithms are left unspecified by the IEEE 802.21 standard so as to promote competion by differentiation of equipment capabilities and services. The contribution of this thesis is two-fold: i) a design and an implemenation of the Media Independent Information Service (MIIS) server; and, ii) a solution to enable network-assisted handover using the IEEE 802.21 standard, aimed at reducing the handover latency and the energy consumption of mobile devices due to scanning.
The MIIS server has been fully implemented in C++ under Linux. In order to perform testbed evaluations, all the required components have been implemented, as well, within an open source framework for IEEE 802.21 called ODTONE. Modifications to the latter have been performed for optimization and fine tuning, and for extending those functional modules needed but not fully implemented.
For a realistic evaluation, Linux-based embedded COTS devices have been used, equipped with multiple IEEE 802.11a and IEEE 802.11g wireless network interface cards. This has required additional development for kernel/user space binding and hardware control.
Testbed results are reported to show the effectiveness of the proposed solution, also proving the MIIS server scalability
Desempenho de redes de acesso heterogéneas com suporte de mobilidade
Mestrado em Engenharia Electrónica e TelecomunicaçõesO desenvolvimento crescente da Internet e das tecnologias sem fios levou à
necessidade de estarmos sempre ligados, onde quer que estejamos, dentro de
casa ou fora, estacionários ou em movimento. O protocolo IEEE 802.21,
desenvolvido pelo grupo IEEE, surge como um mecanismo independente da
tecnologia de acesso que visa optimizar os processos de handover.
Esta dissertação apresenta mecanismos de mobilidade independentes entre as
tecnologias de WiFi, WiMAX e UMTS. São descritos os processos de handover
entre as diferentes tecnologias para efectuar mobilidade transparente, e
optimização do processo de mobilidade através do suporte de servidores com
informação dinâmica da rede.
Posteriormente é analisado o simulador de redes, ferramenta utilizada na
avaliação do desempenho dos handovers em redes heterogéneas através dos
mecanismos apresentados pelo protocolo IEEE 802.21, e são feitas alterações a
estes mesmos mecanismos de forma a optimizar os handovers.
Com a criação de cenários com suporte das diferentes tecnologias de acesso sem
fios, foram realizados, testados e analisados handovers entre as diversas
tecnologias, com e sem suporte de servidores com informação dinâmica da rede.
Através da análise dos resultados obtidos pode-se constatar que as alterações
propostas, em termos da integração do IEEE 802.21 com as diferentes
tecnologias e de disponibilização de informação dinâmica na rede, apresentam
melhorias significativas no processo, e consequente tempo de handover.
ABSTRACT: The growing development of the Internet and the wireless access technologies
lead us to the need of being always connected, wherever we are, at home or
outside, stationary or moving. The IEEE 802.21 protocol, developed by the IEEE
group, comes up as a mechanism independent from the access technology, with
the purpose of improving the handover process.
This thesis presents possible independent mobility mechanisms between WiFi,
WiMAX and UMTS technologies. It is described the handover process between
the different technologies to have transparent mobility, and the optimization of
the mobility process through the support of dynamic information servers.
Later, it is analyzed the network simulator, tool used to evaluate the performance
of the handovers between heterogeneous networks through the mechanisms
presented in the IEEE 802.21 protocol, and are made modifications to the same
mechanisms in order to improve the handovers.
With the creation of scenarios supporting several wireless access technologies,
were made, analyzed and tested handovers between the different technologies,
with and without the support for servers in the network with dynamic
information.
Through the analysis of the obtained results it is possible to see that the
modifications presented, regarding the IEEE 802.21 integration with the
different technologies and the availability of dynamic information in the
network, present significant improvements to the process, and consequent
handover time
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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