34 research outputs found
Models and Methods for Network Selection and Balancing in Heterogeneous Scenarios
The outbreak of 5G technologies for wireless communications can be considered a response to the need for widespread coverage, in terms of connectivity and bandwidth, to guarantee broadband services, such as streaming or on-demand programs offered by the main television networks or new generation services based on augmented and virtual reality (AR / VR).
The purpose of the study conducted for this thesis aims to solve two of the main problems that will occur with the outbreak of 5G, that is, the search for the best possible connectivity, in order to offer users the resources necessary to take advantage of the new generation services, and multicast as required by the eMBMS.
The aim of the thesis is the search for innovative algorithms that will allow to obtain the best connectivity to offer users the resources necessary to use the 5G services in a heterogeneous scenario. Study UF that allows you to improve the search for the best candidate network and to achieve a balance that allows you to avoid congestion of the chosen networks. To achieve these two important focuses, I conducted a study on the main mathematical methods that made it possible to select the network based on QoS parameters based on the type of traffic made by users. A further goal was to improve the computational computation performance they present.
Furthermore, I carried out a study in order to obtain an innovative algorithm that would allow the management of multicast. The algorithm that has been implemented responds to the needs present in the eMBMS, in realistic scenarios
Performance Assessment of Routing Protocols for IoT/6LoWPAN Networks
The Internet of Things (IoT) proposes a disruptive communication paradigm that allows
smart objects to exchange data among themselves to reach a common goal. IoT application
scenarios are multiple and can range from a simple smart home lighting system to fully controlled
automated manufacturing chains. In the majority of IoT deployments, things are equipped with
small devices that can suffer from severe hardware and energy restrictions that are responsible
for performing data processing and wireless communication tasks. Thus, due to their features,
communication networks that are used by these devices are generally categorized as Low Power
and Lossy Networks (LLNs).
The considerable variation in IoT applications represents a critical issue to LLN networks,
which should offer support to different requirements as well as keeping reasonable
quality-of-service (QoS) levels. Based on this challenge, routing protocols represent a key issue
in IoT scenarios deployment. Routing protocols are responsible for creating paths among devices
and their interactions. Hence, network performance and features are highly dependent
on protocol behavior. Also, based on the adopted protocol, the support for some specific requirements
of IoT applications may or may not be provided. Thus, a routing protocol should be
projected to attend the needs of the applications considering the limitations of the device that
will execute them.
Looking to attend the demand of routing protocols for LLNs and, consequently, for IoT
networks, the Internet Engineering Task Force (IETF) has designed and standardized the IPv6
Routing Protocol for Low Power and Lossy Networks (RPL). This protocol, although being robust
and offering features to fulfill the need of several applications, still presents several faults and
weaknesses (mainly related to its high complexity and memory requirement), which limits its
adoption in IoT scenarios. An alternative to RPL, the Lightweight On-demand Ad Hoc Distancevector
Routing Protocol – Next Generation (LOADng) has emerged as a less complicated routing
solution for LLNs. However, the cost of its simplicity is paid for with the absence of adequate
support for a critical set of features required for many IoT environments. Thus, based on the
challenging open issues related to routing in IoT networks, this thesis aims to study and propose
contributions to better attend the network requirements of IoT scenarios. A comprehensive survey,
reviewing state-of-the-art routing protocols adopted for IoT, identified the strengths and
weaknesses of current solutions available in the literature. Based on the identified limitations,
a set of improvements is designed to overcome these issues and enhance IoT network performance.
The novel solutions are proposed to include reliable and efficient support to attend
the needs of IoT applications, such as mobility, heterogeneity, and different traffic patterns.
Moreover, mechanisms to improve the network performance in IoT scenarios, which integrate
devices with different communication technologies, are introduced.
The studies conducted to assess the performance of the proposed solutions showed
the high potential of the proposed solutions. When the approaches presented in this thesis
were compared with others available in the literature, they presented very promising results
considering the metrics related to the Quality of Service (QoS), network and energy efficiency,
and memory usage as well as adding new features to the base protocols. Hence, it is believed
that the proposed improvements contribute to the state-of-the-art of routing solutions for IoT
networks, increasing the performance and adoption of enhanced protocols.A Internet das Coisas, do inglês Internet of Things (IoT), propõe um paradigma de
comunicação disruptivo para possibilitar que dispositivos, que podem ser dotados de comportamentos
autónomos ou inteligentes, troquem dados entre eles buscando alcançar um objetivo
comum. Os cenários de aplicação do IoT são muito variados e podem abranger desde um simples
sistema de iluminação para casa até o controle total de uma linha de produção industrial. Na
maioria das instalações IoT, as “coisas” são equipadas com um pequeno dispositivo, responsável
por realizar as tarefas de comunicação e processamento de dados, que pode sofrer com severas
restrições de hardware e energia. Assim, devido Ă s suas caracterĂsticas, a rede de comunicação
criada por esses dispositivos Ă© geralmente categorizada como uma Low Power and Lossy Network
(LLN).
A grande variedade de cenários IoT representam uma questão crucial para as LLNs,
que devem oferecer suporte aos diferentes requisitos das aplicações, alĂ©m de manter nĂveis
de qualidade de serviço, do inglês Quality of Service (QoS), adequados. Baseado neste desafio,
os protocolos de encaminhamento constituem um aspecto chave na implementação de
cenários IoT. Os protocolos de encaminhamento são responsáveis por criar os caminhos entre
os dispositivos e permitir suas interações. Assim, o desempenho e as caracterĂsticas da rede
sĂŁo altamente dependentes do comportamento destes protocolos. Adicionalmente, com base
no protocolo adotado, o suporte a alguns requisitos especĂficos das aplicações de IoT podem
ou nĂŁo ser fornecidos. Portanto, estes protocolos devem ser projetados para atender as necessidades
das aplicações assim como considerando as limitações do hardware no qual serão
executados.
Procurando atender Ă s necessidades dos protocolos de encaminhamento em LLNs e,
consequentemente, das redes IoT, a Internet Engineering Task Force (IETF) desenvolveu e padronizou
o IPv6 Routing Protocol for Low Power and Lossy Networks (RPL). O protocolo, embora
seja robusto e ofereça recursos para atender às necessidades de diferentes aplicações, apresenta
algumas falhas e fraquezas (principalmente relacionadas com a sua alta complexidade e
necessidade de memória) que limitam sua adoção em cenários IoT. Em alternativa ao RPL, o
Lightweight On-demand Ad hoc Distance-vector Routing Protocol – Next Generation (LOADng)
emergiu como uma solução de encaminhamento menos complexa para as LLNs. Contudo, o
preço da simplicidade é pago com a falta de suporte adequado para um conjunto de recursos
essenciais necessários em muitos ambientes IoT. Assim, inspirado pelas desafiadoras questões
ainda em aberto relacionadas com o encaminhamento em redes IoT, esta tese tem como objetivo
estudar e propor contribuições para melhor atender os requisitos de rede em cenários IoT.
Uma profunda e abrangente revisĂŁo do estado da arte sobre os protocolos de encaminhamento
adotados em IoT identificou os pontos fortes e limitações das soluções atuais. Com base nas debilidades
encontradas, um conjunto de soluções de melhoria é proposto para superar carências
existentes e melhorar o desempenho das redes IoT. As novas soluções são propostas para incluir
um suporte confiável e eficiente capaz atender às necessidades das aplicações IoT relacionadas
com suporte à mobilidade, heterogeneidade dos dispositivos e diferentes padrões de tráfego.
Além disso, são introduzidos mecanismos para melhorar o desempenho da rede em cenários IoT
que integram dispositivos com diferentes tecnologias de comunicação.
Os vários estudos realizados para mensurar o desempenho das soluções propostas mostraram
o grande potencial do conjunto de melhorias introduzidas. Quando comparadas com
outras abordagens existentes na literatura, as soluções propostas nesta tese demonstraram um aumento do desempenho consistente para métricas relacionadas a qualidade de serviço, uso de
memória, eficiência energética e de rede, além de adicionar novas funcionalidades aos protocolos
base. Portanto, acredita-se que as melhorias propostas contribuiem para o avanço do estado
da arte em soluções de encaminhamento para redes IoT e aumentar a adoção e utilização dos
protocolos estudados
Hierarchical network topographical routing
Within the last 10 years the content consumption model that underlies many of the assumptions about traffic aggregation within the Internet has changed; the previous short burst transfer followed by longer periods of inactivity that allowed for statistical aggregation of traffic has been
increasingly replaced by continuous data transfer models. Approaching this issue from a clean slate perspective; this work looks at the design of a network routing structure and supporting protocols for assisting in the delivery of large scale content services. Rather than approaching a content support model through existing IP models the work takes a fresh look at Internet routing through a hierarchical model in order to highlight the benefits that can be gained with a new structural Internet or through similar modifications to the existing IP model. The work is divided into three major sections: investigating the existing UK based Internet structure as compared to the traditional Autonomous System (AS) Internet structural model; a localised hierarchical network topographical routing model; and intelligent distributed localised service models.
The work begins by looking at the United Kingdom (UK) Internet structure as an example of a current generation technical and economic model with shared access to the last mile connectivity and a large scale wholesale network between Internet Service Providers (ISPs) and the end user. This model combined with the Internet Protocol (IP) address allocation and transparency of the wholesale network results in an enforced inefficiency within the overall network restricting the ability of ISPs to collaborate. From this model a core / edge separation hierarchical virtual tree based routing protocol based on the physical network topography (layers 2 and 3) is developed to remove this enforced inefficiency by allowing direct management and control at the lowest levels of the network. This model
acts as the base layer for further distributed intelligent services such as management and content delivery to enable both ISPs and third parties to actively collaborate and provide content from the most efficient source
Design and analysis of a 3-dimensional cluster multicomputer architecture using optical interconnection for petaFLOP computing
In this dissertation, the design and analyses of an extremely scalable distributed
multicomputer architecture, using optical interconnects, that has the potential to
deliver in the order of petaFLOP performance is presented in detail. The design
takes advantage of optical technologies, harnessing the features inherent in optics,
to produce a 3D stack that implements efficiently a large, fully connected system of
nodes forming a true 3D architecture. To adopt optics in large-scale multiprocessor
cluster systems, efficient routing and scheduling techniques are needed. To this
end, novel self-routing strategies for all-optical packet switched networks and on-line
scheduling methods that can result in collision free communication and achieve real
time operation in high-speed multiprocessor systems are proposed. The system is designed
to allow failed/faulty nodes to stay in place without appreciable performance
degradation. The approach is to develop a dynamic communication environment that
will be able to effectively adapt and evolve with a high density of missing units or
nodes. A joint CPU/bandwidth controller that maximizes the resource allocation in
this dynamic computing environment is introduced with an objective to optimize the
distributed cluster architecture, preventing performance/system degradation in the
presence of failed/faulty nodes. A thorough analysis, feasibility study and description of the characteristics of a 3-Dimensional multicomputer system capable of achieving
100 teraFLOP performance is discussed in detail. Included in this dissertation is
throughput analysis of the routing schemes, using methods from discrete-time queuing
systems and computer simulation results for the different proposed algorithms. A
prototype of the 3D architecture proposed is built and a test bed developed to obtain
experimental results to further prove the feasibility of the design, validate initial assumptions,
algorithms, simulations and the optimized distributed resource allocation
scheme. Finally, as a prelude to further research, an efficient data routing strategy
for highly scalable distributed mobile multiprocessor networks is introduced
Recent Trends in Communication Networks
In recent years there has been many developments in communication technology. This has greatly enhanced the computing power of small handheld resource-constrained mobile devices. Different generations of communication technology have evolved. This had led to new research for communication of large volumes of data in different transmission media and the design of different communication protocols. Another direction of research concerns the secure and error-free communication between the sender and receiver despite the risk of the presence of an eavesdropper. For the communication requirement of a huge amount of multimedia streaming data, a lot of research has been carried out in the design of proper overlay networks. The book addresses new research techniques that have evolved to handle these challenges
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Cognitive virtual ad hoc mobile cloud-based networking architecture
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University LondonThis thesis proposed cognitive techniques and intelligent algorithms that offered adaptive and advanced facilities to cloud-based networking by using Virtual Ad Hoc Mobile Cloud Computing Networks architecture (VAMCCNs). This is presented as a working case to address their global network challenges and to add cognitive support to the network design and implementation for better meeting traffic management and application requirements in mission objectives. The thesis concentrates on three main contributions.
Firstly, an adaptive model, namely: a Heterogeneous Mobile Cloud Computing Network (HMCCN), was proposed to integrate different cloud networks architectures into one workflow. The cognitive data offloading task and the routing decision methods were applied using two different approaches: Fuzzy Analytic Hierarchy system (FAH) as a first approach and cognitive Software Defined Network (SDN) model as a second centralised approach. Experimental results show improvement in network reliability and throughputs, minimised in both nodes’ energy consumption and network latency with efficient intelligent data load balance and network resources allocation with best cloud model selection.
Secondly, based on a virtual Ad Hoc cloud network with a realistic Random Waypoint Motion (RWM) model, an innovative cognitive routing algorithm was presented to improve efficient and reliable route selection among multiple possible routes. Routing protocols based on conventional, Fuzzy logic used important parameters with two data collections and decisions techniques and a new adaptive Intelligent Hybrid Fuzzy-Neural routing protocol (IHFN) that included prior knowledge to the network of the underlying motion and energy parameters were all proposed and compared. Results with the new hybrid algorithm shown a significant improvement to solve the network end-to-end performance degradation problem. The new hybrid protocol improved network throughput with an average of 20% higher than traditional Ad Hoc On-Demand Distance Vector (AODV) Routing protocol, improved the usage of network resources and reduced the maintenance process in adynamic topologies network.
Finally, based on datasets collected from a realistic motion RWM model in a virtual Ad Hoc cloud network, the performance behaviour of six selected deep learning algorithms to predict the next steps of positions, speed and residual battery energy values of these mobile nodes have been evaluated and compared. This work goes further by presenting two algorithm's training techniques to predict the next 300-time steps of position, speed, and energy. Results and dissuasion show the differences concerning prediction accuracy between using the single node dataset model or Multiple node's dataset model
Privacy-preserving spatiotemporal multicast for mobile information services
Mobile devices have become essential for accessing information services anywhere at any time. While the so-called geographic multicast (geocast) has been considered in detail in existing research, it only focuses on delivering messages to all mobile devices that are currently residing within a certain geographic area. This thesis extends this notion by introducing a Spatiotemporal Multicast (STM), which can informally be described as a "geocast into the past". Instead of addressing users based on their current locations, this concept relates to the challenge of sending a message to all devices that have resided within a geographic area at a certain time in the past. While a wide variety of applications can be envisioned for this concept, it presents several challenges to be solved. In order to deliver messages to all past visitors of a certain location, an STM service would have to fully track all user movements at all times. However, collecting this kind of information is not desirable considering the underlying privacy implications, i.e., users may not wish to be identified by the sender of a message as this can disclose sensitive personal information. Consequently, this thesis aims to provide a privacy-preserving notion of STM. In order to realize such a service, this work first presents a detailed overview of possible applications. Based on those, functional, non-functional, as well as security and privacy objectives are proposed. These objectives provide the foundation for an in-depth literature review of potential mechanisms for realizing an STM service. Among the suggested options, the most promising relies on Rendezvous Points (RPs) for datagram delivery. In simple terms, RPs represent "anonymous mailboxes" that are responsible for certain spatiotemporal regions. Messages are deposited at RPs so that users can retrieve them later on. Protecting the privacy of users then translates to obfuscating the responsibilities of RPs for specific spatiotemporal regions. This work proposes two realizations: CSTM, which relies on cryptographic hashing, and OSTM, which considers the use of order-preserving encryption in a CAN overlay. Both approaches are evaluated and compared in detail with respect to the given objectives. While OSTM yields superior performance-related properties, CSTM provides an increased ability of protecting the privacy of users.Mobilgeräte bilden heute die Grundlage allgegenwärtiger Informationsdienste. Während der sogenannte geografische Multicast (Geocast) hier bereits ausführlich erforscht worden ist, so bezieht sich dieser nur auf Geräte, welche sich aktuell innerhalb einer geografischen Zielregion befinden. Diese Arbeit erweitert dieses Konzept durch einen räumlich-zeitlichen Multicast, welcher sich informell als "Geocast in die Vergangenheit" beschreiben lässt. Dabei wird die Zustellung einer Nachricht an alle Nutzer betrachtet, die sich in der Vergangenheit an einem bestimmten Ort aufgehalten haben. Während eine Vielzahl von Anwendungen für dieses Konzept denkbar ist, so ergeben sich hier mehrere Herausforderungen. Um Nachrichten an ehemalige Besucher eines Ortes senden zu können, müsste ein räumlich-zeitlicher Multicast-Dienst die Bewegungen aller Nutzer vollständig erfassen. Aus Gründen des Datenschutzes ist das zentralisierte Sammeln solch sensibler personenbezogener Daten jedoch nicht wünschenswert. Diese Arbeit befasst sich daher insbesondere mit dem Schutz der Privatsphäre von Nutzern eines solchen Dienstes. Zur Entwicklung eines räumlich-zeitlichen Multicast-Dienstes erörtert diese Arbeit zunächst mögliche Anwendungen. Darauf aufbauend werden funktionale, nicht-funktionale, sowie Sicherheits- und Privatsphäre-relevante Anforderungen definiert. Diese bilden die Grundlage einer umfangreichen Literaturrecherche relevanter Realisierungstechniken. Der vielversprechendste Ansatz basiert hierbei auf der Hinterlegung von Nachrichten in sogenannten Rendezvous Points. Vereinfacht betrachtet stellen diese "anonyme Briefkästen" für bestimmte räumlich-zeitliche Regionen dar. Nachrichten werden in diesen so hinterlegt, dass legitime Empfänger sie dort später abholen können. Der Schutz der Nutzer-Privatsphäre entspricht dann der Verschleierung der Zuständigkeiten von Rendezvous Points für verschiedene räumlich-zeitliche Regionen. Diese Arbeit schlägt zwei Ansätze vor: CSTM, welches kryptografische Hashfunktionen nutzt, sowie OSTM, welches ordnungserhaltende Verschlüsselung in einem CAN Overlay einsetzt. Beide Optionen werden detailliert analytisch sowie empirisch bezüglich ihrer Diensteigenschaften untersucht und verglichen. Dabei zeigt sich, dass OSTM vorteilhaftere Leistungseigenschaften besitzt, während CSTM einen besseren Schutz der Nutzer-Privatsphäre bietet
Analysis, design and experimental evaluation of connectivity management in heterogeneous wireless environments
MenciĂłn Internacional en el tĂtulo de doctorThe future of network communications is mobile as many more users demand for ubiquitous connectivity. Wireless has become the primary access technology or even the only one, leading to an explosion in traffic demand. This challenges network providers to manage and configure new requirements without incrementing costs in the same amount.
In addition to the growth in the use of mobile devices, there is a need to operate simultaneously different access technologies. As well, the great diversity of applications and the capabilities of mobile terminals makes possible for us to live in a hyper-connected world and offers new scenarios. This heterogeneity poses great challenges that need to be addressed to offer better performance and seamless experience to the final user. We need to orchestrate solutions to increase flexibility and empower interoperability.
Connectivity management is handled from different angles. In the network stack, mobility is more easily handled by IP mobility protocols, since IP is the common layer between the different access technologies and the application diversity. From the end-user perspective, the connection manager is in charge of handling connectivity issues in mobile devices, but it is an unstandardized entity so its performance is heavily implementation-dependent.
In this thesis we explore connectivity management from different angles. We study mobility protocols as they are part of our proposed solutions. In most of the cases we include an experimental evaluation of performance with 3G and IEEE 802.11 as the main technologies. We consider heterogeneous scenarios, with several access technologies where mobile devices have also several network interfaces. We evaluate how connectivity is handled as well as its influence in a handover. Based on the analysis of real traces from a cellular network, we confirm the suitability of more efficient mobility management.
Moreover, we propose and evaluate three different solutions for providing mobility support in three different heterogeneous scenarios. We perform an experimental evaluation of a vehicular route optimization for network mobility, reporting on the challenges and lessons learned in such a complicated networking environment. We propose an architecture for supporting mobility and enhance handover in a passive optical network deployment. In addition, we design and deploy a mechanism for mobility management based on software-defined networking.Programa Oficial de Doctorado en IngenierĂa TelemáticaPresidente: Arturo Azcorra Saloña.- Secretario: RamĂłn AgĂĽero Calvo.- Vocal: Daniel Nunes Coruj