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Interoperability of wireless communication technologies in hybrid networks: Evaluation of end-to-end interoperability issues and quality of service requirements
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Hybrid Networks employing wireless communication technologies have nowadays brought closer the vision of communication “anywhere, any time with anyone”. Such communication technologies consist of various standards, protocols, architectures, characteristics, models, devices, modulation and coding techniques. All these different technologies naturally may share some common characteristics, but there are also many important differences. New advances in these technologies are emerging very rapidly, with the advent of new models, characteristics, protocols and architectures. This rapid evolution imposes many challenges and issues to be addressed, and of particular importance are the interoperability issues of the following wireless technologies: Wireless Fidelity (Wi-Fi) IEEE802.11, Worldwide Interoperability for Microwave Access (WiMAX) IEEE 802.16, Single Channel per Carrier (SCPC), Digital Video Broadcasting of Satellite (DVB-S/DVB-S2), and Digital Video Broadcasting Return Channel through Satellite (DVB-RCS). Due to the differences amongst wireless technologies, these technologies do not generally interoperate easily with each other because of various interoperability and Quality of Service (QoS) issues.
The aim of this study is to assess and investigate end-to-end interoperability issues and QoS requirements, such as bandwidth, delays, jitter, latency, packet loss, throughput, TCP performance, UDP performance, unicast and multicast services and availability, on hybrid wireless communication networks (employing both satellite broadband and terrestrial wireless technologies).
The thesis provides an introduction to wireless communication technologies followed by a review of previous research studies on Hybrid Networks (both satellite and terrestrial wireless technologies, particularly Wi-Fi, WiMAX, DVB-RCS, and SCPC). Previous studies have discussed Wi-Fi, WiMAX, DVB-RCS, SCPC and 3G technologies and their standards as well as their properties and characteristics, such as operating frequency, bandwidth, data rate, basic configuration, coverage, power, interference, social issues, security problems, physical and MAC layer design and development issues. Although some previous studies provide valuable contributions to this area of research, they are limited to link layer characteristics, TCP performance, delay, bandwidth, capacity, data rate, and throughput. None of the studies cover all aspects of end-to-end interoperability issues and QoS requirements; such as bandwidth, delay, jitter, latency, packet loss, link performance, TCP and UDP performance, unicast and multicast performance, at end-to-end level, on Hybrid wireless networks.
Interoperability issues are discussed in detail and a comparison of the different technologies and protocols was done using appropriate testing tools, assessing various performance measures including: bandwidth, delay, jitter, latency, packet loss, throughput and availability testing. The standards, protocol suite/ models and architectures for Wi-Fi, WiMAX, DVB-RCS, SCPC, alongside with different platforms and applications, are discussed and compared. Using a robust approach, which includes a new testing methodology and a generic test plan, the testing was conducted using various realistic test scenarios on real networks, comprising variable numbers and types of nodes. The data, traces, packets, and files were captured from various live scenarios and sites. The test results were analysed in order to measure and compare the characteristics of wireless technologies, devices, protocols and applications.
The motivation of this research is to study all the end-to-end interoperability issues and Quality of Service requirements for rapidly growing Hybrid Networks in a comprehensive and systematic way.
The significance of this research is that it is based on a comprehensive and systematic investigation of issues and facts, instead of hypothetical ideas/scenarios or simulations, which informed the design of a test methodology for empirical data gathering by real network testing, suitable for the measurement of hybrid network single-link or end-to-end issues using proven test tools.
This systematic investigation of the issues encompasses an extensive series of tests measuring delay, jitter, packet loss, bandwidth, throughput, availability, performance of audio and video session, multicast and unicast performance, and stress testing. This testing covers most common test scenarios in hybrid networks and gives recommendations in achieving good end-to-end interoperability and QoS in hybrid networks.
Contributions of study include the identification of gaps in the research, a description of interoperability issues, a comparison of most common test tools, the development of a generic test plan, a new testing process and methodology, analysis and network design recommendations for end-to-end interoperability issues and QoS requirements. This covers the complete cycle of this research.
It is found that UDP is more suitable for hybrid wireless network as compared to TCP, particularly for the demanding applications considered, since TCP presents significant problems for multimedia and live traffic which requires strict QoS requirements on delay, jitter, packet loss and bandwidth. The main bottleneck for satellite communication is the delay of approximately 600 to 680 ms due to the long distance factor (and the finite speed of light) when communicating over geostationary satellites.
The delay and packet loss can be controlled using various methods, such as traffic classification, traffic prioritization, congestion control, buffer management, using delay compensator, protocol compensator, developing automatic request technique, flow scheduling, and bandwidth allocation
Interoperability of wireless communication technologies in hybrid networks : evaluation of end-to-end interoperability issues and quality of service requirements
Hybrid Networks employing wireless communication technologies have nowadays brought closer the vision of communication “anywhere, any time with anyone”. Such communication technologies consist of various standards, protocols, architectures, characteristics, models, devices, modulation and coding techniques. All these different technologies naturally may share some common characteristics, but there are also many important differences. New advances in these technologies are emerging very rapidly, with the advent of new models, characteristics, protocols and architectures. This rapid evolution imposes many challenges and issues to be addressed, and of particular importance are the interoperability issues of the following wireless technologies: Wireless Fidelity (Wi-Fi) IEEE802.11, Worldwide Interoperability for Microwave Access (WiMAX) IEEE 802.16, Single Channel per Carrier (SCPC), Digital Video Broadcasting of Satellite (DVB-S/DVB-S2), and Digital Video Broadcasting Return Channel through Satellite (DVB-RCS). Due to the differences amongst wireless technologies, these technologies do not generally interoperate easily with each other because of various interoperability and Quality of Service (QoS) issues. The aim of this study is to assess and investigate end-to-end interoperability issues and QoS requirements, such as bandwidth, delays, jitter, latency, packet loss, throughput, TCP performance, UDP performance, unicast and multicast services and availability, on hybrid wireless communication networks (employing both satellite broadband and terrestrial wireless technologies). The thesis provides an introduction to wireless communication technologies followed by a review of previous research studies on Hybrid Networks (both satellite and terrestrial wireless technologies, particularly Wi-Fi, WiMAX, DVB-RCS, and SCPC). Previous studies have discussed Wi-Fi, WiMAX, DVB-RCS, SCPC and 3G technologies and their standards as well as their properties and characteristics, such as operating frequency, bandwidth, data rate, basic configuration, coverage, power, interference, social issues, security problems, physical and MAC layer design and development issues. Although some previous studies provide valuable contributions to this area of research, they are limited to link layer characteristics, TCP performance, delay, bandwidth, capacity, data rate, and throughput. None of the studies cover all aspects of end-to-end interoperability issues and QoS requirements; such as bandwidth, delay, jitter, latency, packet loss, link performance, TCP and UDP performance, unicast and multicast performance, at end-to-end level, on Hybrid wireless networks. Interoperability issues are discussed in detail and a comparison of the different technologies and protocols was done using appropriate testing tools, assessing various performance measures including: bandwidth, delay, jitter, latency, packet loss, throughput and availability testing. The standards, protocol suite/ models and architectures for Wi-Fi, WiMAX, DVB-RCS, SCPC, alongside with different platforms and applications, are discussed and compared. Using a robust approach, which includes a new testing methodology and a generic test plan, the testing was conducted using various realistic test scenarios on real networks, comprising variable numbers and types of nodes. The data, traces, packets, and files were captured from various live scenarios and sites. The test results were analysed in order to measure and compare the characteristics of wireless technologies, devices, protocols and applications. The motivation of this research is to study all the end-to-end interoperability issues and Quality of Service requirements for rapidly growing Hybrid Networks in a comprehensive and systematic way. The significance of this research is that it is based on a comprehensive and systematic investigation of issues and facts, instead of hypothetical ideas/scenarios or simulations, which informed the design of a test methodology for empirical data gathering by real network testing, suitable for the measurement of hybrid network single-link or end-to-end issues using proven test tools. This systematic investigation of the issues encompasses an extensive series of tests measuring delay, jitter, packet loss, bandwidth, throughput, availability, performance of audio and video session, multicast and unicast performance, and stress testing. This testing covers most common test scenarios in hybrid networks and gives recommendations in achieving good end-to-end interoperability and QoS in hybrid networks. Contributions of study include the identification of gaps in the research, a description of interoperability issues, a comparison of most common test tools, the development of a generic test plan, a new testing process and methodology, analysis and network design recommendations for end-to-end interoperability issues and QoS requirements. This covers the complete cycle of this research. It is found that UDP is more suitable for hybrid wireless network as compared to TCP, particularly for the demanding applications considered, since TCP presents significant problems for multimedia and live traffic which requires strict QoS requirements on delay, jitter, packet loss and bandwidth. The main bottleneck for satellite communication is the delay of approximately 600 to 680 ms due to the long distance factor (and the finite speed of light) when communicating over geostationary satellites. The delay and packet loss can be controlled using various methods, such as traffic classification, traffic prioritization, congestion control, buffer management, using delay compensator, protocol compensator, developing automatic request technique, flow scheduling, and bandwidth allocation.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Avaliação de desempenho e mobilidade em redes auto-organizadas
Mestrado em Engenharia de Computadores e TelemáticaAs redes móveis ad hoc (ou auto-organizadas) são um assunto que nos últimos
anos tem ganho muita atenção da comunidade científica. Os problemas associados
a este tipo de redes foram amplamente estudados e expostos, foram
propostas soluções, e algumas até foram tornadas um padrão da indústria.
No entanto, a grande maioria do trabalho realizado, é dedicado a resolver só
um problema de cada vez. Da mesma forma, as soluções que são testadas
por forma a verificar a sua validade, muitas das vezes, são testadas recorrendo
a trabalho de simulação. Uma parte do trabalho que é apresentado
nesta dissertação de mestrado, junta uma série de protocolos desenvolvidos
para redes ad hoc, os quais providenciam funcionalidades como: auto configuração,
encaminhamento unicast e multicast, qualidade de serviço e taxação
com incentivos numa única solução integrada que interliga as redes ad hoc
a redes infra-estruturadas funcionando como uma extensão das mesmas. O
demonstrador criado é avaliado de forma experimental, e os resultados obtidos
são apresentados e discutidos. Uma vez que a rede ad hoc está interligada à
rede infra-estruturada, num ambiente de quarta geração, é também apresentada
uma arquitectura que suporta mobilidade de nós entre redes ad hoc e as
redes infra-estuturadas que fazem parte do ambiente heterogéneo, e de este
para as redes ad hoc é apresentada. A rede geral onde a rede ad hoc é integrada
suporta novas tecnologias e tendências em gestão de mobilidade, tais
como o protocolo em desenvolvimento IEEE 802.21 Media Independent Handover
e gestão de mobilidade baseada em Domínios de Mobilidade Local. A
forma como a rede ad hoc se integra com as tecnologias presentes na rede
infra-estruturada, e como as especificidades da rede ad hoc são escondidas, é
descrita e explicada.
ABSTRACT: Mobile Ad hoc network is a subject that has gained lots of attention from the
research community in recent years. The problems inherent to this types of networks
have been studied and exposed, solutions have been created and even
standardized. However, the vast majority of the work performed is dedicated to
only one problem at the time. In addition, the tests performed to validate the
produced solutions are, most of the times, obtained through simulation work.
The work presented in this thesis gathers together a set of ad hoc protocols,
providing functionalities such as auto-configuration, unicast and multicast routing,
quality of service and charging and rewarding in one integrated testbed,
serving as a stub network in a hotspot scenario. A experimental evaluation is
performed, and results are presented and discussed. Additionally, since the
network belongs to a hotspot of fourth generation, a architecture that supports
mobility of nodes between the ad hoc network and infrastructure networks is
presented. The general network that includes ad hoc network integrates and
supports the new technologies and tendencies in mobility management, such
as the IEEE 802.21 Media Independent Handover and mobility management
based on Local Mobility Domains. The way the MANET fully integrates with the
infrastructure network, and how the ad hoc networks specific characteristics
are hidden, is also presented and explained
Avaliação de controlo de sessões multicast em redes com contexto
Mestrado em Engenharia Electrónica e TelecomunicaçõesOs utilizadores pretendem aceder, cada vez mais, a serviços multimédia com
requisitos mais exigentes e personalizados. As limitações impostas pelos
ambientes existentes (internet, 3G) para fornecer estes serviços levam à
procura de melhores soluções, nomeadamente uma gestão eficaz das sessões
multiparty. Neste tipo de soluções é normalmente utilizado o multicast, já que
este permite reduzir os recursos utilizados, diminuindo o número de pacotes na
rede. Contudo, o multicast não está consistente ao nível dos cenários de
mobilidade, fundamentais nas redes de próxima geração.
Actualmente existe uma vasta gama de tecnologias de acesso sem fios como
WiFi, GPRS, UMTS e WiMAX. No futuro estas tecnologias diferentes
complementar-se-ão convergindo numa infra-estrutura heterogénea capaz de
fornecer um melhor serviço aos utilizadores, denominadas de redes 4G. A
evolução dos terminais móveis também permitirá que estes se liguem
simultaneamente a várias redes de acesso. Para uma melhor distribuição dos
serviços dos utilizadores pelas redes de acesso disponíveis são necessários
novos mecanismos de selecção. Uma nova selecção da rede baseada em
informação de contexto (entidades e ambiente) tem tido grande relevo na
comunidade científica. Assim, aplicações e rede reagem a alterações de
contexto para uma melhor selecção da mesma.
A dissertação apresentada encontra-se no âmbito do transporte multiparty com
informação de contexto e reserva de recursos, permitindo a entrega do
conteúdo de uma forma personalizada e com Qualidade de Serviço a vários
utilizadores móveis, independentemente da tecnologia de acesso de cada um
e da própria tecnologia da rede. Em suma, é utilizada uma arquitectura de rede
baseada em informação de contexto e que reage eficazmente a alterações do
mesmo.
De forma a implementar a proposta apresentada recorreu-se à criação de
várias entidades no simulador de redes NS-2. Os resultados foram obtidos
usando diferentes cenários, avaliando a influência de cada parâmetro
individualmente. Demonstrou-se que a arquitectura implementada permite
suportar uma entrega dos conteúdos de uma maneira personalizada e
independente da tecnologia utilizada. Obteve-se ainda uma boa gestão dos
recursos da rede e uma melhoria na experiência percepcionada pelo utilizador
através da selecção total da rede com base numa entidade de controlo central.
A introdução do overlay de transporte multiparty melhora o comportamento
geral da rede, minimizando as reconfigurações frequentes necessárias.Nowadays, more and more users want to access multimedia services with
strong and personalized requirements. The limitations intrinsic to current
environments (Internet and 3G) to provide this type of services motivate the
research for an efficient management of multiparty sessions. The solution can
also be based on multicast implementation, since it reduces resources
utilization, decreasing the number of packets in the network. However, current
multicast is not a strong solution in mobility scenarios, essential in next
generation networks.
Currently there is a wide range of wireless access technologies such as WiFi,
GPRS, UMTS and WiMAX. In the future, these different technologies will
converge in a complementary manner forming a heterogeneous infrastructure
able to offer a better service to its users, usually named 4G. The evolution of
mobile terminals will also allow them to connect simultaneously to several
access networks. In order to a better distribution of the users services
throughout available access networks, new selection mechanisms are required.
A new network selection based on context information (entities and
environments) is having a relevant role in scientific community. So, applications
and networks react according to context changes, improving network selection.
This Thesis is in the scope of context-aware multiparty transport with resources
allocation, allowing the delivery of content in a personalized way with Quality of
Service to several users, independently of the technology and the network.
Resuming, the solution implements a context-aware network architecture that
reacts efficiently to its changes.
In order to implement this architecture, new entities were created in the network
simulator NS-2. The results were obtained using different scenarios, evaluating
the influence of each parameter independently. It was demonstrated that the
integration of several components, allows a delivery of contents in a
personalized manner and independently of the technology. The results showed
a better management of the network resources and users experience,
throughout the total network selection, based on a central control unit. The
multiparty transport overlay improves the network behaviour, minimizing the
necessary frequent reconfigurations
Rigorous and Practical Proportional-fair Allocation for Multi-rate Wi-Fi
Recent experimental studies confirm the prevalence of the widely known performance anomaly
problem in current Wi-Fi networks, and report on the severe network utility degradation caused by
this phenomenon. Although a large body of work addressed this issue, we attribute the refusal of
prior solutions to their poor implementation feasibility with off-the-shelf hardware and their impre-
cise modelling of the 802.11 protocol. Their applicability is further challenged today by very high
throughput enhancements (802.11n/ac) whereby link speeds can vary by two orders of magnitude.
Unlike earlier approaches, in this paper we introduce the first rigorous analytical model of 802.11
stations’ throughput and airtime in multi-rate settings, without sacrificing accuracy for tractability.
We use the proportional-fair allocation criterion to formulate network utility maximisation as a con-
vex optimisation problem for which we give a closed-form solution. We present a fully functional
light-weight implementation of our scheme on commodity access points and evaluate this extensively
via experiments in a real deployment, over a broad range of network conditions. Results demonstrate
that our proposal achieves up to 100% utility gains, can double video streaming goodput and reduces
TCP download times by 8x
Wi-Fi Enabled Healthcare
Focusing on its recent proliferation in hospital systems, Wi-Fi Enabled Healthcare explains how Wi-Fi is transforming clinical work flows and infusing new life into the types of mobile devices being implemented in hospitals. Drawing on first-hand experiences from one of the largest healthcare systems in the United States, it covers the key areas associated with wireless network design, security, and support. Reporting on cutting-edge developments and emerging standards in Wi-Fi technologies, the book explores security implications for each device type. It covers real-time location services and emerging trends in cloud-based wireless architecture. It also outlines several options and design consideration for employee wireless coverage, voice over wireless (including smart phones), mobile medical devices, and wireless guest services. This book presents authoritative insight into the challenges that exist in adding Wi-Fi within a healthcare setting. It explores several solutions in each space along with design considerations and pros and cons. It also supplies an in-depth look at voice over wireless, mobile medical devices, and wireless guest services. The authors provide readers with the technical knowhow required to ensure their systems provide the reliable, end-to-end communications necessary to surmount today’s challenges and capitalize on new opportunities. The shared experience and lessons learned provide essential guidance for large and small healthcare organizations in the United States and around the world. This book is an ideal reference for network design engineers and high-level hospital executives that are thinking about adding or improving upon Wi-Fi in their hospitals or hospital systems
Internet Access and QoS in Ad Hoc Networks
It is likely that the increased popularity of wireless local area networks (WLANs) together with the continuous technological advances in wireless communication, also increase the interest for ad hoc networks. An ad hoc network is a wireless, autonomous, infrastructure-less network composed of stations that communicate with each other directly in a peer-to-peer fashion. When discussing mobile ad hoc networks (MANETs), we often refer to an ad hoc network where the stations cooperate in forwarding packets on behalf of each other to allow communication beyond their transmission range over multi-hop paths. In order to realize the practical benefits of ad hoc networks, two challenges (among others) need to be considered: distributed quality of service (QoS) guarantees and multi-hop Internet access. This thesis presents conceivable solutions to both of these problems. The first two papers focus on the network layer and consider the provisioning of Internet access to ad hoc networks whereas the last two papers focus on the data link layer and investigate the provisioning of QoS to ad hoc networks. The first paper studies the interconnection between a MANET and the Internet. In addition, it evaluates three approaches for gateway discovery, which can be initiated by the gateway (proactive method), by the mobile station (reactive method) or by mixing these two approaches (hybrid method). The second paper also studies Internet access for MANETs, but with focus on micro mobility, i.e. mobile stations moving from one gateway to another. In particular, it evaluates a solution that allows mobile stations to access the Internet and roam from gateway to gateway. The third paper, gives an overview of the medium access mechanisms in IEEE 802.11 and their QoS limitations. Moreover, it proposes an enhancement to the contention-free medium access mechanism of IEEE 802.11e to provide QoS guarantees in WLANs operating in ad hoc network configuration. The fourth paper continues the work from the third paper by enhancing the scheme and dealing with the problems that occur due to hidden stations. Furthermore, it discusses how to deal with the problems that occur when moving from single-hop ad hoc networks (i.e. WLANs in ad hoc network configuration) to multi-hop ad hoc networks
Smart PIN: performance and cost-oriented context-aware personal information network
The next generation of networks will involve interconnection of heterogeneous individual
networks such as WPAN, WLAN, WMAN and Cellular network, adopting the IP as common infrastructural protocol and providing virtually always-connected network. Furthermore,
there are many devices which enable easy acquisition and storage of information as pictures, movies, emails, etc. Therefore, the information overload and divergent content’s
characteristics make it difficult for users to handle their data in manual way. Consequently, there is a need for personalised automatic services which would enable data exchange across heterogeneous network and devices. To support these personalised services, user centric approaches
for data delivery across the heterogeneous network are also required.
In this context, this thesis proposes Smart PIN - a novel performance and cost-oriented context-aware Personal Information Network. Smart PIN's architecture is detailed including its network, service and management components. Within the service component, two novel schemes for efficient delivery of context and content data are proposed:
Multimedia Data Replication Scheme (MDRS) and Quality-oriented Algorithm for Multiple-source Multimedia Delivery (QAMMD).
MDRS supports efficient data accessibility among distributed devices using data replication which is based on a utility function and a minimum data set. QAMMD employs a buffer underflow avoidance scheme for streaming, which achieves high multimedia quality without content adaptation to network conditions. Simulation models for MDRS and
QAMMD were built which are based on various heterogeneous network scenarios. Additionally a multiple-source streaming based on QAMMS was implemented as a prototype and tested in an emulated network environment. Comparative tests show that MDRS and QAMMD perform significantly better than other approaches