3 research outputs found
Technology Integration Framework for Fast and Low Cost Handovers—Case Study: WiFi-WiMAX Network
The Next Generation Wireless Networks (NGWNs) are seemed to be heterogeneous networks based on the integration of several wireless technologies. These networks are required
to achieve performances equivalent to classic wireless networks by ensuring the continuity of communications and the homogeneity of network management during horizontal and vertical handovers. This task is even more important when management services, like security and quality of service (QoS), are deployed at access technology level. In this paper, we propose a framework for heterogeneous wireless technology integration based on network architecture skeleton and a handover management mechanism. This framework optimizes the layer-2 handover procedure to achieve performances required by sensitive applications while ensuring the minimization of signaling overhead required for operated networks. As an application example, we make use of this framework to propose a heterogeneous network based on WiFi and WiMAX technologies. We present an application example of the framework using the specification of a WiFi-WiMAX network. We propose several performance evaluations based on simulation tests based on this application. The latter confirm the efficiency of handover delay optimization and the minimization of management signaling costs
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
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