598 research outputs found
Wireless communications in the new millennium and third generation wireless networks
At the end of the 20 century, and at the beginning of this one, wireless communications are making large advances. The new technologies are on the way to provide a high-speed, high-quality information exchange between handheld terminals, and information repositories. The so called 2,5 generation networks, using the techniques like the HSCSD1, GPRS2, EDGE3, and the 3r generation wireless systems will help the wireless world to reach those goals. In this thesis I will start from the first and second-generation wireless networks, and then look into the 2,5 generation and 3rd generation wireless communications more in detail. The latest advances in the wireless world are the main focus of this paper although a short history of wireless communications is also given. The various aspects related to 3rd generation systems will be explored in this thesis, for example the air interface discussions, its time scale, its elements like the mobile equipment, software and security, USLM4, services that will be offered, etc. In addition, the technical factors and key technologies that are likely to shape the wireless network environment of the future will be explored. This part is expected to help us to see beyond the 3rd generation
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An Emergent Architecture for Scaling Decentralized Communication Systems (DCS)
With recent technological advancements now accelerating the mobile and wireless Internet solution space, a ubiquitous computing Internet is well within the research and industrial community's design reach - a decentralized system design, which is not solely driven by static physical models and sound engineering principals, but more dynamically, perhaps sub-optimally at initial deployment and socially-influenced in its evolution. To complement today's Internet system, this thesis proposes a Decentralized Communication System (DCS) architecture with the following characteristics: flat physical topologies with numerous compute oriented and communication intensive nodes in the network with many of these nodes operating in multiple functional roles; self-organizing virtual structures formed through alternative mobility scenarios and capable of serving ad hoc networking formations; emergent operations and control with limited dependency on centralized control and management administration. Today, decentralized systems are not commercially scalable or viable for broad adoption in the same way we have to come to rely on the Internet or telephony systems. The premise in this thesis is that DCS can reach high levels of resilience, usefulness, scale that the industry has come to experience with traditional centralized systems by exploiting the following properties: (i.) network density and topological diversity; (ii.) self-organization and emergent attributes; (iii.) cooperative and dynamic infrastructure; and (iv.) node role diversity. This thesis delivers key contributions towards advancing the current state of the art in decentralized systems. First, we present the vision and a conceptual framework for DCS. Second, the thesis demonstrates that such a framework and concept architecture is feasible by prototyping a DCS platform that exhibits the above properties or minimally, demonstrates that these properties are feasible through prototyped network services. Third, this work expands on an alternative approach to network clustering using hierarchical virtual clusters (HVC) to facilitate self-organizing network structures. With increasing network complexity, decentralized systems can generally lead to unreliable and irregular service quality, especially given unpredictable node mobility and traffic dynamics. The HVC framework is an architectural strategy to address organizational disorder associated with traditional decentralized systems. The proposed HVC architecture along with the associated promotional methodology organizes distributed control and management services by leveraging alternative organizational models (e.g., peer-to-peer (P2P), centralized or tiered) in hierarchical and virtual fashion. Through simulation and analytical modeling, we demonstrate HVC efficiencies in DCS structural scalability and resilience by comparing static and dynamic HVC node configurations against traditional physical configurations based on P2P, centralized or tiered structures. Next, an emergent management architecture for DCS exploiting HVC for self-organization, introduces emergence as an operational approach to scaling DCS services for state management and policy control. In this thesis, emergence scales in hierarchical fashion using virtual clustering to create multiple tiers of local and global separation for aggregation, distribution and network control. Emergence is an architectural objective, which HVC introduces into the proposed self-management design for scaling and stability purposes. Since HVC expands the clustering model hierarchically and virtually, a clusterhead (CH) node, positioned as a proxy for a specific cluster or grouped DCS nodes, can also operate in a micro-capacity as a peer member of an organized cluster in a higher tier. As the HVC promotional process continues through the hierarchy, each tier of the hierarchy exhibits emergent behavior. With HVC as the self-organizing structural framework, a multi-tiered, emergent architecture enables the decentralized management strategy to improve scaling objectives that traditionally challenge decentralized systems. The HVC organizational concept and the emergence properties align with and the view of the human brain's neocortex layering structure of sensory storage, prediction and intelligence. It is the position in this thesis, that for DCS to scale and maintain broad stability, network control and management must strive towards an emergent or natural approach. While today's models for network control and management have proven to lack scalability and responsiveness based on pure centralized models, it is unlikely that singular organizational models can withstand the operational complexities associated with DCS. In this work, we integrate emergence and learning-based methods in a cooperative computing manner towards realizing DCS self-management. However, unlike many existing work in these areas which break down with increased network complexity and dynamics, the proposed HVC framework is utilized to offset these issues through effective separation, aggregation and asynchronous processing of both distributed state and policy. Using modeling techniques, we demonstrate that such architecture is feasible and can improve the operational robustness of DCS. The modeling emphasis focuses on demonstrating the operational advantages of an HVC-based organizational strategy for emergent management services (i.e., reachability, availability or performance). By integrating the two approaches, the DCS architecture forms a scalable system to address the challenges associated with traditional decentralized systems. The hypothesis is that the emergent management system architecture will improve the operational scaling properties of DCS-based applications and services. Additionally, we demonstrate structural flexibility of HVC as an underlying service infrastructure to build and deploy DCS applications and layered services. The modeling results demonstrate that an HVC-based emergent management and control system operationally outperforms traditional structural organizational models. In summary, this thesis brings together the above contributions towards delivering a scalable, decentralized system for Internet mobile computing and communications
Wireless communication, identification and sensing technologies enabling integrated logistics: a study in the harbor environment
In the last decade, integrated logistics has become an important challenge in
the development of wireless communication, identification and sensing
technology, due to the growing complexity of logistics processes and the
increasing demand for adapting systems to new requirements. The advancement of
wireless technology provides a wide range of options for the maritime container
terminals. Electronic devices employed in container terminals reduce the manual
effort, facilitating timely information flow and enhancing control and quality
of service and decision made. In this paper, we examine the technology that can
be used to support integration in harbor's logistics. In the literature, most
systems have been developed to address specific needs of particular harbors,
but a systematic study is missing. The purpose is to provide an overview to the
reader about which technology of integrated logistics can be implemented and
what remains to be addressed in the future
Mobility management in 5G heterogeneous networks
In recent years, mobile data traffic has increased exponentially as a result of widespread popularity and uptake of portable devices, such as smartphones, tablets and laptops. This growth has placed enormous stress on network service providers who are committed to offering the best quality of service to consumer groups. Consequently, telecommunication engineers are investigating innovative solutions to accommodate the additional load offered by growing numbers of mobile users.
The fifth generation (5G) of wireless communication standard is expected to provide numerous innovative solutions to meet the growing demand of consumer groups. Accordingly the ultimate goal is to achieve several key technological milestones including up to 1000 times higher wireless area capacity and a significant cut in power consumption.
Massive deployment of small cells is likely to be a key innovation in 5G, which enables frequent frequency reuse and higher data rates. Small cells, however, present a major challenge for nodes moving at vehicular speeds. This is because the smaller coverage areas of small cells result in frequent handover, which leads to lower throughput and longer delay.
In this thesis, a new mobility management technique is introduced that reduces the number of handovers in a 5G heterogeneous network. This research also investigates techniques to accommodate low latency applications in nodes moving at vehicular speeds
Digital Ecosystems: Ecosystem-Oriented Architectures
We view Digital Ecosystems to be the digital counterparts of biological
ecosystems. Here, we are concerned with the creation of these Digital
Ecosystems, exploiting the self-organising properties of biological ecosystems
to evolve high-level software applications. Therefore, we created the Digital
Ecosystem, a novel optimisation technique inspired by biological ecosystems,
where the optimisation works at two levels: a first optimisation, migration of
agents which are distributed in a decentralised peer-to-peer network, operating
continuously in time; this process feeds a second optimisation based on
evolutionary computing that operates locally on single peers and is aimed at
finding solutions to satisfy locally relevant constraints. The Digital
Ecosystem was then measured experimentally through simulations, with measures
originating from theoretical ecology, evaluating its likeness to biological
ecosystems. This included its responsiveness to requests for applications from
the user base, as a measure of the ecological succession (ecosystem maturity).
Overall, we have advanced the understanding of Digital Ecosystems, creating
Ecosystem-Oriented Architectures where the word ecosystem is more than just a
metaphor.Comment: 39 pages, 26 figures, journa
A Generic Network and System Management Framework
Networks and distributed systems have formed the basis of an ongoing communications revolution
that has led to the genesis of a wide variety of services. The constantly increasing size and
complexity of these systems does not come without problems. In some organisations, the
deployment of Information Technology has reached a state where the benefits from downsizing and
rightsizing by adding new services are undermined by the effort required to keep the system
running.
Management of networks and distributed systems in general has a straightforward goal: to provide
a productive environment in which work can be performed effectively. The work required for
management should be a small fraction of the total effort. Most IT systems are still managed in an
ad hoc style without any carefully elaborated plan. In such an environment the success of
management decisions depends totally on the qualification and knowledge of the administrator.
The thesis provides an analysis of the state of the art in the area of Network and System
Management and identifies the key requirements that must be addressed for the provisioning of
Integrated Management Services. These include the integration of the different management related
aspects (i.e. integration of heterogeneous Network, System and Service Management).
The thesis then proposes a new framework, INSMware, for the provision of Management Services.
It provides a fundamental basis for the realisation of a new approach to Network and System
Management. It is argued that Management Systems can be derived from a set of pre-fabricated
and reusable Building Blocks that break up the required functionality into a number of separate
entities rather than being developed from scratch. It proposes a high-level logical model in order to
accommodate the range of requirements and environments applicable to Integrated Network and
System Management that can be used as a reference model.
A development methodology is introduced that reflects principles of the proposed approach, and
provides guidelines to structure the analysis, design and implementation phases of a management
system. The INSMware approach can further be combined with the componentware paradigm for
the implementation of the management system. Based on these principles, a prototype for the
management of SNMP systems has been implemented using industry standard middleware
technologies. It is argued that development of a management system based on Componentware
principles can offer a number of benefits. INSMware Components may be re-used and system
solutions will become more modular and thereby easier to construct and maintain
Managing data on the World Wide Web : state of the art survey of innovative tools and techniques
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1995.Includes bibliographical references (p. 96-102).by Prasanth Duvvur.M.S
Future Trends and Challenges for Mobile and Convergent Networks
Some traffic characteristics like real-time, location-based, and
community-inspired, as well as the exponential increase on the data traffic in
mobile networks, are challenging the academia and standardization communities
to manage these networks in completely novel and intelligent ways, otherwise,
current network infrastructures can not offer a connection service with an
acceptable quality for both emergent traffic demand and application requisites.
In this way, a very relevant research problem that needs to be addressed is how
a heterogeneous wireless access infrastructure should be controlled to offer a
network access with a proper level of quality for diverse flows ending at
multi-mode devices in mobile scenarios. The current chapter reviews recent
research and standardization work developed under the most used wireless access
technologies and mobile access proposals. It comprehensively outlines the
impact on the deployment of those technologies in future networking
environments, not only on the network performance but also in how the most
important requirements of several relevant players, such as, content providers,
network operators, and users/terminals can be addressed. Finally, the chapter
concludes referring the most notable aspects in how the environment of future
networks are expected to evolve like technology convergence, service
convergence, terminal convergence, market convergence, environmental awareness,
energy-efficiency, self-organized and intelligent infrastructure, as well as
the most important functional requisites to be addressed through that
infrastructure such as flow mobility, data offloading, load balancing and
vertical multihoming.Comment: In book 4G & Beyond: The Convergence of Networks, Devices and
Services, Nova Science Publishers, 201
Calypso Service Architecture for Broadband Networks
The Calypso project aims at developing an extremely flexible control and service architecture for ATM-based broadband networks. This architecture provides various alternatives to distribute the network and service control functions among clients, servers and different network nodes. This means that a control or service function can reside not only in a network node, but in the customer's workstation or in the service provider's dedicated server. Instead of the traditional ATM or IN signalling, the Calypso architecture uses the TCP/IP protocol suite for the management and control of the network and services. The management, control and user data is transferred by means of IP switching. In addition to IP switching, the architecture will support endto -end native ATM streams with guaranteed Quality of Service. In this paper we compare the Calypso architecture with the traditional B-ISDN and IN architectures. We focus on describing the Java-based Service Execution Environment that provides..
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