159 research outputs found
Lifetime Estimation of Wireless Body Area Sensor Network for Patient Health Monitoring
Wireless Body Area Sensor Networks (WBASN) is an emerging technology which utilizes wireless sensors to implement real-time wearable health monitoring of patients to enhance independent living. These sensors can be worn externally to monitor multiple bio-parameters (such as blood oxygen saturation (SpO2), blood pressure and heart activity) of multiple patients at a central location in the hospital.
In health monitoring, the loss of critical or emergency information is a serious issue so there is a concern for quality of service which needs to be addressed. It is important to have an estimate of the time the first node will fail in order to replace or recharge the battery. A common type of failure happens when a node runs out of energy and shuts down.
In this work, Monte Carlo simulation is used to determine the lifetime of WBASN. The lifetime of the WBASN is defined in this work as the duration of time until the first sensor failure due to battery depletion. A parametric model of the health care network is created with sets of random input distributions. Probabilistic analysis is used to determine the timing and distributions of nodes\u27 failures in the health monitoring network
Avaliação de controlo de sessÔes multicast em redes com contexto
Mestrado em Engenharia Electrónica e TelecomunicaçÔesOs utilizadores pretendem aceder, cada vez mais, a serviços multimédia com
requisitos mais exigentes e personalizados. As limitaçÔes impostas pelos
ambientes existentes (internet, 3G) para fornecer estes serviços levam Ă
procura de melhores soluçÔes, nomeadamente uma gestão eficaz das sessÔes
multiparty. Neste tipo de soluçÔes é normalmente utilizado o multicast, jå que
este permite reduzir os recursos utilizados, diminuindo o nĂșmero de pacotes na
rede. Contudo, o multicast nĂŁo estĂĄ consistente ao nĂvel dos cenĂĄrios 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 permitirå que estes se liguem
simultaneamente a vårias redes de acesso. Para uma melhor distribuição dos
serviços dos utilizadores pelas redes de acesso disponĂveis sĂŁo necessĂĄrios
novos mecanismos de selecção. Uma nova selecção da rede baseada em
informação de contexto (entidades e ambiente) tem tido grande relevo na
comunidade cientĂfica. Assim, aplicaçÔes e rede reagem a alteraçÔes de
contexto para uma melhor selecção da mesma.
A dissertação apresentada encontra-se no ùmbito do transporte multiparty com
informação de contexto e reserva de recursos, permitindo a entrega do
conteĂșdo de uma forma personalizada e com Qualidade de Serviço a vĂĄrios
utilizadores mĂłveis, independentemente da tecnologia de acesso de cada um
e da prĂłpria tecnologia da rede. Em suma, Ă© utilizada uma arquitectura de rede
baseada em informação de contexto e que reage eficazmente a alteraçÔes do
mesmo.
De forma a implementar a proposta apresentada recorreu-se à criação de
vĂĄrias entidades no simulador de redes NS-2. Os resultados foram obtidos
usando diferentes cenĂĄrios, avaliando a influĂȘncia de cada parĂąmetro
individualmente. Demonstrou-se que a arquitectura implementada permite
suportar uma entrega dos conteĂșdos de uma maneira personalizada e
independente da tecnologia utilizada. Obteve-se ainda uma boa gestĂŁo dos
recursos da rede e uma melhoria na experiĂȘncia 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 reconfiguraçÔes frequentes necessårias.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
Flexible Application-Layer Multicast in Heterogeneous Networks
This work develops a set of peer-to-peer-based protocols and extensions in order to provide Internet-wide group communication. The focus is put to the question how different access technologies can be integrated in order to face the growing traffic load problem. Thereby, protocols are developed that allow autonomous adaptation to the current network situation on the one hand and the integration of WiFi domains where applicable on the other hand
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 contentâs
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
ComunicaçÔes veiculares hĂbridas
Vehicle Communications is a promising research field, with a great potential for
the development of new applications capable of improving road safety, traffic efficiency,
as well as passenger comfort and infotainment. Vehicle communication
technologies can be short-range, such as ETSI ITS-G5 or the 5G PC5 sidelink
channel, or long-range, using the cellular network (LTE or 5G). However, none of
the technologies alone can support the expected variety of applications for a large
number of vehicles, nor all the temporal and spatial requirements of connected
and autonomous vehicles. Thus, it is proposed the collaborative or hybrid use of
short-range communications, with lower latency, and of long-range technologies,
potentially with higher latency, but integrating aggregated data of wider geographic
scope.
In this context, this work presents a hybrid vehicle communications model, capable
of providing connectivity through two Radio Access Technologies (RAT), namely,
ETSI ITS-G5 and LTE, to increase the probability of message delivery and, consequently,
achieving a more robust, efficient and secure vehicle communication
system. The implementation of short-range communication channels is done using
Raw Packet Sockets, while the cellular connection is established using the Advanced
Messaging Queuing Protocol (AMQP) protocol.
The main contribution of this dissertation focuses on the design, implementation
and evaluation of a Hybrid Routing Sublayer, capable of isolating messages that
are formed/decoded from transmission/reception processes. This layer is, therefore,
capable of managing traffic coming/destined to the application layer of intelligent
transport systems (ITS), adapting and passing ITS messages between the highest
layers of the protocol stack and the available radio access technologies.
The Hybrid Routing Sublayer also reduces the financial costs due to the use of
cellular communications and increases the efficiency of the use of the available
electromagnetic spectrum, by introducing a cellular link controller using a Beacon
Detector, which takes informed decisions related to the need to connect to a cellular
network, according to different scenarios.
The experimental results prove that hybrid vehicular communications meet the requirements
of cooperative intelligent transport systems, by taking advantage of
the benefits of both communication technologies. When evaluated independently,
the ITS-G5 technology has obvious advantages in terms of latency over the LTE
technology, while the LTE technology performs better than ITS-G5, in terms of
throughput and reliability.As ComunicaçÔes Veiculares são um campo de pesquisa promissor, com um grande
potencial de desenvolvimento de novas aplicaçÔes capazes de melhorar a segurança
nas estradas, a eficiĂȘncia do trĂĄfego, bem com o conforto e entretenimento dos
passageiros. As tecnologias de comunicação veĂcular podem ser de curto alcance,
como por exemplo ETSI ITS-G5 ou o canal PC5 do 5G, ou de longo alcance, recorrendo
Ă rede celular (LTE ou 5G). No entanto, nenhuma das tecnologias por
si sĂł, consegue suportar a variedade expectĂĄvel de aplicaçÔes para um nĂșmero de
veĂculos elevado nem tampouco todos os requisitos temporais e espaciais dos veĂculos
conectados e autĂłnomos. Assim, Ă© proposto o uso colaborativo ou hĂbrido de
comunicaçÔes de curto alcance, com latĂȘncias menores, e de tecnologias de longo
alcance, potencialmente com maiores latĂȘncias, mas integrando dados agregados
de maior abrangĂȘncia geogrĂĄfica.
Neste contexto, este trabalho apresenta um modelo de comunicaçÔes veiculares
hĂbrido, capaz de fornecer conectividade por meio de duas Tecnologias de Acesso
por RĂĄdio (RAT), a saber, ETSI ITS-G5 e LTE, para aumentar a probabilidade de
entrega de mensagens e, consequentemente, alcançar um sistema de comunicação
veicular mais robusto, eficiente e seguro. A implementação de canais de comunicação
de curto alcance é feita usando Raw Packet Sockets, enquanto que a ligação
celular Ă© estabelecida usando o protocolo Advanced Messaging Queuing Protocol
(AMQP).
A contribuição principal desta dissertação foca-se no projeto, implementação e avaliação
de uma sub camada hibrĂda de encaminhamento, capaz de isolar mensagens
que se formam/descodificam a partir de processos de transmissão/receção. Esta
camadada Ă©, portanto, capaz de gerir o trĂĄfego proveniente/destinado Ă camada
de aplicação de sistemas inteligentes de transportes (ITS) adaptando e passando
mensagens ITS entre as camadas mais altas da pilha protocolar e as tecnologias
de acesso rĂĄdio disponĂveis.
A sub camada hibrĂda de encaminhamento tambĂ©m potencia uma redução dos custos
financeiros devidos ao uso de comunicaçÔes celulares e aumenta a eficiĂȘncia do
uso do espectro electromagnĂ©tico disponĂvel, ao introduzir um mĂșdulo controlador
da ligação celular, utilizando um Beacon Detector, que toma decisÔes informadas
relacionadas com a necessidade de uma conexĂŁo a uma rede celular, de acordo com
diferentes cenĂĄrios.
Os resultados experimentais comprovam que as comunicaçÔes veĂculares hĂbridas
cumprem os requisitos dos sistemas cooperativos de transporte inteligentes, ao
tirarem partido das vantagens de ambas tecnologias de comunicação. Quando
avaliadas de forma independente, constata-se que que a tecnologia ITS-G5 tem
vantagens evidentes em termos de latĂȘncia sobre a tecnologia LTE, enquanto que
a tecnologia LTE tem melhor desempenho que a LTE, ai nĂvel de dĂ©bito e fiabilidade.Mestrado em Engenharia EletrĂłnica e TelecomunicaçÔe
Recommended from our members
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 âanywhere, any time with anyoneâ. 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
Adaptive load balancing routing algorithms for the next generation wireless telecommunications networks
This thesis was submitted for the degree of Doctor of Philosophy and was awarded by Brunel UniversityWith the rapid development of wireless networks, mesh networks are evolving as a new important technology, presenting a high research and commercial interest. Additionally, wireless mesh networks have a wide variety of applications, offering the ability to provide network access in both rural and urban areas with low cost of maintenance. One of the main functionalities of a wireless mesh network is load balancing routing, which is the procedure of finding the best, according to some criteria, routes that data need to follow to transfer from one node to another. Routing is one of the state-of-the-art areas of research because the current algorithms and protocols are not efficient and effective due to the diversity of the characteristics of these networks. In this thesis, two new routing algorithms have been developed for No Intra-Cell Interference (NICI) and Limited Intra-Cell Interference (LICI) networks based on WiMAX, the most advanced wireless technology ready for deployment. The algorithms created are based on the classical Dijkstra and Ford-Fulkerson algorithms and can be implemented in the cases of unicast and multicast transmission respectively.State scholarships foundation of Greece
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 nodeâs network selection by reducing the delay associated and the packet losses incurred
13. Ilmenauer TK-Manager Workshop: Technische UniversitÀt Ilmenau, 12. September 2014 ; Tagungsband
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