49 research outputs found
MOBILITY SUPPORT ARCHITECTURES FOR NEXT-GENERATION WIRELESS NETWORKS
With the convergence of the wireless networks and the Internet and the booming
demand for multimedia applications, the next-generation (beyond the third generation, or
B3G) wireless systems are expected to be all IP-based and provide real-time and non-real-time
mobile services anywhere and anytime. Powerful and efficient mobility support is
thus the key enabler to fulfil such an attractive vision by supporting various mobility
scenarios. This thesis contributes to this interesting while challenging topic.
After a literature review on mobility support architectures and protocols, the thesis
starts presenting our contributions with a generic multi-layer mobility support framework,
which provides a general approach to meet the challenges of handling comprehensive
mobility issues. The cross-layer design methodology is introduced to coordinate the
protocol layers for optimised system design. Particularly, a flexible and efficient cross-layer
signalling scheme is proposed for interlayer interactions. The proposed generic
framework is then narrowed down with several fundamental building blocks identified to
be focused on as follows.
As widely adopted, we assume that the IP-based access networks are organised into
administrative domains, which are inter-connected through a global IP-based wired core
network. For a mobile user who roams from one domain to another, macro (inter-domain)
mobility management should be in place for global location tracking and effective handoff
support for both real-time and non-real-lime applications. Mobile IP (MIP) and the Session
Initiation Protocol (SIP) are being adopted as the two dominant standard-based macro-mobility
architectures, each of which has mobility entities and messages in its own right.
The work explores the joint optimisations and interactions of MIP and SIP when utilising
the complementary power of both protocols. Two distinctive integrated MIP-SIP
architectures are designed and evaluated, compared with their hybrid alternatives and other
approaches. The overall analytical and simulation results shown significant performance
improvements in terms of cost-efficiency, among other metrics.
Subsequently, for the micro (intra-domain) mobility scenario where a mobile user
moves across IP subnets within a domain, a micro mobility management architecture is
needed to support fast handoffs and constrain signalling messaging loads incurred by intra-domain
movements within the domain. The Hierarchical MIPv6 (HMIPv6) and the Fast
Handovers for MIPv6 (FMIPv6) protocols are selected to fulfil the design requirements.
The work proposes enhancements to these protocols and combines them in an optimised
way. resulting in notably improved performances in contrast to a number of alternative
approaches
Mobile Networks
The growth in the use of mobile networks has come mainly with the third generation systems and voice traffic. With the current third generation and the arrival of the 4G, the number of mobile users in the world will exceed the number of landlines users. Audio and video streaming have had a significant increase, parallel to the requirements of bandwidth and quality of service demanded by those applications. Mobile networks require that the applications and protocols that have worked successfully in fixed networks can be used with the same level of quality in mobile scenarios. Until the third generation of mobile networks, the need to ensure reliable handovers was still an important issue. On the eve of a new generation of access networks (4G) and increased connectivity between networks of different characteristics commonly called hybrid (satellite, ad-hoc, sensors, wired, WIMAX, LAN, etc.), it is necessary to transfer mechanisms of mobility to future generations of networks. In order to achieve this, it is essential to carry out a comprehensive evaluation of the performance of current protocols and the diverse topologies to suit the new mobility conditions
Handover in Mobile WiMAX Networks: The State of Art and Research Issues
The next-generation Wireless Metropolitan Area
Networks, using the Worldwide Interoperability for Microwave
Access (WiMAX) as the core technology based on the IEEE
802.16 family of standards, is evolving as a Fourth-Generation
(4G) technology. With the recent introduction of mobility management
frameworks in the IEEE 802.16e standard, WiMAX
is now placed in competition to the existing and forthcoming
generations of wireless technologies for providing ubiquitous
computing solutions. However, the success of a good mobility
framework largely depends on the capability of performing fast
and seamless handovers irrespective of the deployed architectural
scenario. Now that the IEEE has defined the Mobile WiMAX
(IEEE 802.16e) MAC-layer handover management framework,
the Network Working Group (NWG) of the WiMAX Forum
is working on the development of the upper layers. However,
the path to commercialization of a full-fledged WiMAX mobility
framework is full of research challenges. This article focuses on
potential handover-related research issues in the existing and
future WiMAX mobility framework. A survey of these issues in
the MAC, Network and Cross-Layer scenarios is presented along
with discussion of the different solutions to those challenges. A
comparative study of the proposed solutions, coupled with some
insights to the relevant issues, is also included
Intégration et gestion de mobilité de bout en bout dans les réseaux mobiles de prochaine génération
Résumé - Pendant les dix dernières années, l'utilisation des systèmes de communication sans fil est devenue de plus en plus populaire tant chez les entreprises que chez les particuliers. Cette nouvelle tendance du marché est due, en grande partie, à la performance grandissante des réseaux mobiles qui concurrencent davantage les réseaux filaires en termes de bande passante, de coût et de couverture. Toutefois, cette catégorie de solutions sans fil est conçue pour des services spécifiques et utilise des technologies très variées. De plus, les usagers sont de plus en plus mobiles et requièrent des applications sensibles au délai (voix, multimédia, etc.).
Dans ce nouveau contexte de mobilité, la prochaine génération des réseaux sans fil (4G) s'annonce comme l'ultime solution visant à satisfaire les exigences des usagers tout en tirant profit de la complémentarité des services offerts par les systèmes mobiles existants. Pour ce faire, la principale vocation de la future génération (4G) consiste en l'intégration et la convergence des technologies sans fil existantes et celles à venir. Cette intégration passe obligatoirement par l'utilisation du protocole IP (Internet Protocol) qui permet de cacher l'hétérogénéité des systèmes intégrés puisqu'il demeure l'unique couche commune à toutes les plateformes mobiles.
Plusieurs solutions d'intégration ont été proposées dans la littérature. Celles-ci concernent des architectures d'intégration et des mécanismes de gestion de mobilité. Cependant, les approches proposées ne font pas l'unanimité et souffrent de plusieurs handicaps liés, en particulier, à l'interopérabilité et la garantie des relèves sans coupures.----------ABSTRACT
During the last few years, the use of wireless systems is becoming more and more popular. This tendency can be explained by the fact that mobile technologies are gaining in performance in terms of bandwidth, coverage and cost compared to the traditional wired solutions. However, each mobile network is tailored for a specific type of services and users. Moreover, end users are expected to become more and more mobile and show an increasing interest to real-time applications. In these circumstances, the next generation of mobile networks (4G) appears to be the ultimate solution that will satisfy mobile user demands and take benefit of the existing wireless systems. Indeed, the future generation consists of integrating, in an intelligent manner, the existing/future wireless systems in a way that users can obtain their services via the best available network.
This integration passes through the use of the Internet Protocol (IP) that will hide the heterogeneity pertaining to the integrated networks. To deal with this very important task, several solutions are available in the literature. The proposed approaches cover some basic topics such as interworking architecture and mobility management. Nevertheless, these proposals suffer from drawbacks relevant to the guarantee of QoS through heterogeneous technologies
Mecanismos de mobilidade rápida com suporte de QdS
Mestrado em Engenharia Electrónica e TelecomunicaçõesA área das redes de comunicações está, neste momento, a deparar-se com
um novo paradigma causado pela tendência de convergência de redes sem
fios e celulares. Desta convergência resultará a existência de uma camada de
rede integradora, para facilitar o suporte de mecanismos de Qualidade de
Serviço e mobilidade. Aqui, o suporte de mobilidade rápida e transparente,
sem ser perceptível pelo utilizador, tem sido alvo de muita atenção, apesar de
ainda existirem algumas limitações no seu suporte. A mobilidade transparente
entre redes celulares, sem fios e fixas, é ambicionada mas ainda não foi
alcançada.
O trabalho realizado nesta Dissertação consiste na descrição, especificação,
implementação e teste de uma nova arquitectura de mobilidade sobre o
protocolo IP. Esta arquitectura é baseada no protocolo de mobilidade Mobility
Support for IPv6 e em extensões de Fast Handovers for Mobile IPv6, sendo
capaz de efectuar handovers iniciados pelo terminal e pela rede. A mobilidade
é transparente entre tecnologias de acesso heterogéneas, através da
integração de mecanismos de qualidade de serviço, tais como autorização de
handovers, controlo de acesso, reserva e atribuição de recursos no novo ponto
de ligação e também integrada com subsistemas de autenticação. São
também propostos outros mecanismos de mobilidade rápida que fazem uso do
protocolo multicast para distribuir os fluxos de tráfego direccionados ao
terminal, pelos routers de acesso vizinhos, permitindo que os terminais móveis
mudem para qualquer router de acesso na vizinhança sem interrupção dos
serviços em curso. Estes mecanismos foram projectados para terminais
móveis com grandes requisitos de mobilidade.
No âmbito do projecto IST Daidalos foi efectuada a integração de uma rede de
próxima geração (4G) de forma a permitir a realização de testes de
desempenho e conformidade aos mecanismos propostos. A presente
Dissertação efectua uma avaliação de desempenho de uma arquitectura de
mobilidade, em cenários intra- e inter-tecnologia, numa rede de testes real.
Nesta avaliação foram utilizadas as métricas de atraso, jitter e perdas de
pacotes nas fases de preparação e execução do handover. O impacto deste
processo em comunicações de dados sobre TCP e UDP é também analisado.
A arquitectura e os resultados obtidos no demonstrador real são apresentados
e discutidos.
ABSTRACT: The field of network communications is, nowadays, facing a new paradigm
caused by the forthcoming convergence of cellular and wireless data networks,
which seems unavoidable. This convergence will result on an integration layer,
to ease the support for Quality of Service and mobility mechanisms. Here, the
support for fast and seamless mobility, not perceptible by the user, has been
getting much attention, although several limitations still exist in this support.
Seamless mobility between cellular, wireless and wired data networks is
envisioned, but not yet achieved.
The work performed in the scope of this thesis aims to describe, specify,
implement and test a novel mobility architecture based on the IP protocol. This
architecture is based on the mobility protocol Mobility Support for IPv6 and on
extensions of Fast Handovers for Mobile IPv6 RFCs, and is able to provide
mobile terminal and network initiated handovers. The mobility is seamless
across heterogeneous access technologies, by integrating Quality of Service
mechanisms, such as handover authorization, access control, resources
reservation and allocation at the new point of attachment, also integrated with
an authentication sub-system. Other novel fast mobility mechanisms are also
proposed, which make use of the multicast protocol to distribute the traffic flows
directed to the terminal during the handover process among the neighbour
access routers, allowing the terminal to handover to any access router in the
vicinity without disruption of the ongoing services. These latter mechanisms
were designed to mobile terminals with high mobility requirements.
In the scope of the IST Daidalos framework an integration process of a next
generation (4G) network was carried out in order to perform performance and
compliance tests to the proposed mechanisms. Furthermore, this thesis also
evaluates the performance of a mobility architecture, both in intra and intertechnology
scenarios, in a real testbed. In this evaluation were considered
metrics such as packet delay, jitter and loss of the handover in its preparation
and execution phases. The impact of the handover on ongoing TCP and UDP
data communications is also addressed. The architecture and results obtained
from the real demonstrator are also presented and discussed
Architectural and mobility management designs in internet-based infrastructure wireless mesh networks
Wireless mesh networks (WMNs) have recently emerged to be a cost-effective solution to support large-scale wireless Internet access. They have numerous ap- plications, such as broadband Internet access, building automation, and intelligent transportation systems. One research challenge for Internet-based WMNs is to design efficient mobility management techniques for mobile users to achieve seamless roam- ing. Mobility management includes handoff management and location management. The objective of this research is to design new handoff and location management techniques for Internet-based infrastructure WMNs.
Handoff management enables a wireless network to maintain active connections as mobile users move into new service areas. Previous solutions on handoff manage- ment in infrastructure WMNs mainly focus on intra-gateway mobility. New handoff issues involved in inter-gateway mobility in WMNs have not been properly addressed. Hence, a new architectural design is proposed to facilitate inter-gateway handoff man- agement in infrastructure WMNs. The proposed architecture is designed to specifi- cally address the special handoff design challenges in Internet-based WMNs. It can facilitate parallel executions of handoffs from multiple layers, in conjunction with a data caching mechanism which guarantees minimum packet loss during handoffs. Based on the proposed architecture, a Quality of Service (QoS) handoff mechanism is also proposed to achieve QoS requirements for both handoff and existing traffic before and after handoffs in the inter-gateway WMN environment.
Location management in wireless networks serves the purpose of tracking mobile users and locating them prior to establishing new communications. Existing location management solutions proposed for single-hop wireless networks cannot be directly applied to Internet-based WMNs. Hence, a dynamic location management framework
in Internet-based WMNs is proposed that can guarantee the location management performance and also minimize the protocol overhead. In addition, a novel resilient location area design in Internet-based WMNs is also proposed. The formation of the location areas can adapt to the changes of both paging load and service load so that the tradeoff between paging overhead and mobile device power consumption can be balanced, and at the same time, the required QoS performance of existing traffic is maintained. Therefore, together with the proposed handoff management design, efficient mobility management can be realized in Internet-based infrastructure WMNs
Vertical Handoff between 802.11 and 802.16 Wireless Access Networks
Heterogeneous wireless networks will be dominant in the next-generation wireless networks with the integration of various wireless access networks. Wireless mesh networks will become to a key technology as an economically viable solution for wide deployment of high speed, scalable and ubiquitous wireless Internet services. In this thesis, we consider an interworking architecture of wireless mesh backbone and propose an effective vertical handoff scheme between 802.11 and 802.16 wireless access networks. The proposed vertical handoff scheme aims at reducing handoff signaling overhead on the wireless backbone and providing a low handoff delay to mobile nodes. The handoff signaling procedure in different scenarios is discussed. Together with call admission control, the vertical handoff scheme directs a new call request in the 802.11 network to the 802.16 network, if the admission of the new call in the 802.11 network can degrade quality-of-service (QoS) of the existing real-time traffic flows. Simulation results demonstrate the performance of the handoff scheme with respect to signaling cost, handoff delay, and QoS support
Architecture d'interopérabilité et mécanismes de relève pour les réseaux sans fil de prochaine génération
Intégration, interopéribilité et mobilité -- An analytical framework for performance evaluation of IPV6-Based mobility management protocols -- An architecture for seamless mobility support in Ip-Based next generation wireless networks -- Adaptive handoff scheme for heterogeneous ip wireless networks -- Enhanced fast handoff scheme for heterogeneous wireless networks