RWSoftware

Displaying 1-40 of 270 results

  • White Papers // Nov 2014

    Component-Based Specification of Software Product Line Architecture

    Software product lines have known an increasing use over the last years, taking advantage from the important benefits they may bring to software development in terms of time, cost and effort. However, product line approaches remain immature owing to the fact that they still base on traditional design concepts of...

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  • White Papers // Nov 2014

    Dealing with Deviations on Software Process Enactment : Comparison Framework

    Software development is a collective and complex task carried out through the cooperation of human agents and automated tools, this interaction defines the software process. PSEE (Process-centered Software Engineering Environment) are environments designed to support the creation and exploitation of software process models that define the expected behaviors of process...

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  • White Papers // Nov 2014

    Modeling Channel Allocation via BRS: Case of WMNs

    Wireless Mesh Networks (WMNs), is an emerging wireless technology which attracts more and more attention of service providers and enterprises. The main advantage of this new class of network is to offer a flexible and economical way to expand internet access. Their major concern is to improve the flow and...

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  • White Papers // Nov 2014

    Generating FoCaLiZe Specifications from UML Models

    UML is the defacto standard language to graphically describe systems in an object oriented way. Once an application has been modeled, Model Driven Architecture (MDA) techniques can be applied to generate code from such models. Because UML lacks formal basis to analyze and check model consistency, it is pertinent to...

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  • White Papers // Nov 2014

    BiCloud-2M: A Combined Bigraph Maude-based Tool for Cloud Specification and Analysis

    Service availability is a challenging issue in cloud computing. It implies continuous reconfiguration of cloud architecture by adding or removing different resources (virtual machines and services) to ensure the suited quality of service. Thus a main goal in cloud systems design is to model and analyze cloud architecture and its...

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  • White Papers // Nov 2014

    A Highly Adaptive Leader Election Algorithm for Mobile Ad Hoc Networks

    Leader election has been identified as a basic building block in distributed computing. MANETs are distinct from traditional distributed systems as they are dynamic and self-organizing networks because of their dynamic wireless link formation and removal, network partitioning and disconnections, limited bandwidth and energy and highly variable message delay. These...

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  • White Papers // Nov 2014

    Software Component Quality Evaluation

    Component-Based Software Engineering (CBSE) provides for developers the ability to easily reuse and assemble software entities to build complex software. It is based on the composition of prefabricated software entities called components. In this paper, the selection step is very important. It consists of searching and selecting appropriate software components...

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  • White Papers // Nov 2014

    A New Distributed Anonymization Protocol to Satisfy Multiple Data Provider's Privacy Requirements

    Privacy and security concerns are among the main obstacles facing the widespread adoption of this new technology. Data anonymization makes data worthless to anyone except the owner of the data. It is one of the methods for transforming the data in such a way that it prevents identification of key...

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  • White Papers // Nov 2014

    Ontology-Driven and Community-Based Framework for Services Description and Selection of Composite Services

    In this paper, the authors propose OWL DL ontology for web service description which aims at automating selection of composite web services. In this ontology, they identify communities as a mean to organize web services for a given shared domain. They relate concepts of community, service's functionality (atomic abstract service...

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  • White Papers // Nov 2014

    Specifing and Verifing Aspect-Oriented Systems in Rewriting Logic

    Aspect-Oriented (AO) systems have to deal with an important problem which is the management of aspect interaction. In this paper, the authors introduce a first tool, known as AO-Maude, which is based on Maude language for the specification and the verification of the AO systems. The proposed tool relies on...

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  • White Papers // Nov 2014

    A Multi-Objective Hybrid Particle Swarm Optimization-Based Service Identification

    Service identification step is a basic requirement for a detailed design and implementation of services in a Service Oriented Architecture (SOA). Existing methods for service identification ignore the automation capability while providing human based prescriptive guidelines, which mostly are not applicable at enterprise scales. In this paper, the authors propose...

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  • White Papers // Nov 2014

    Formal Specification of Multi-Agent System Architecture

    Multi-Agent Systems (MAS) are an emerging paradigm that has high potentials for developing distributed, open and concurrent complex systems. These systems often need to operate in dynamic environments and face the challenges of handling continuously changing requirements. These aspects increase the complexity of designing MAS. To handle the complexity and...

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  • White Papers // Nov 2014

    K-Maude Definition of Dynamic Software Architecture

    One of the complex issues in developing architectural models of software systems is the capturing of architectures dynamics, i.e., systems for which composition of interacting components, changes at run time. In this paper, the authors argue that it is possible and valuable to provide a Dynamic Software Architecture Meta-model (DySAM)...

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  • White Papers // Nov 2014

    The Wi-STARK Architecture for Resilient Real-Time Wireless Communications

    Networking communications play an important role to secure a dependable and timely operation of distributed and real-time embedded system applications; however, an effective real-time support is not yet properly addressed in the wireless realm. This paper presents Wi-STARK, a novel architecture for resilient and real-time wireless communications within a one-hop...

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  • White Papers // Nov 2014

    Constant Bandwidth Server Revisited

    The Constant Bandwidth Server (CBS) is an algorithm for providing temporal protection and real-time guarantees to real-time sporadic tasks. Recently, an implementation of this algorithm called SCHED-DEADLINE has been included in the Linux kernel. Therefore, the CBS algorithm is now used to serve more generic tasks than do not obey...

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  • White Papers // Nov 2014

    Validation of a Security Metamodel for Development of Cloud Applications

    Development of secure cloud applications requires a supportive approach that should also enable software assessment and certification by different mechanisms. These can assure by independent means that the required security is present. In this paper, the authors present a Core Security Meta-model (CSM) that is the director of a security...

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  • White Papers // Nov 2014

    On Metamodel Superstructures Employing UML Generalization Features

    The authors employ UML generalization features in order to describe multi-level meta-models and their connections. The basic idea is to represent several meta-model levels in one UML and OCL model and to connect the meta-models with (what they call) a superstructure. The advantage of having various levels in one model...

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  • White Papers // Oct 2014

    Software Analytics for MDE Communities

    The MDE research community has grown significantly in size and maturity in the last decade. During these years, a plethora of languages and tools has been proposed to address different challenges of the MDE approach to software development. As the community continues to broaden its expertise, it is worthwhile to...

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  • White Papers // Oct 2014

    Energy Efficiency Embedded Service Lifecycle: Towards an Energy Efficient Cloud Computing Architecture

    Cloud computing aims to streamline the on-demand provisioning of software, hardware, and data to provide flexibility and agility, and economies of scale in IT resource management. The paper argues the need to provide novel methods and tools to support software developers aiming to optimize energy efficiency and minimize the carbon...

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  • White Papers // Oct 2014

    Privacy-Preserving Indoor Localization

    Upcoming Wi-Fi-based localization systems for indoor environments face a conflict of privacy interests: server-side localization violates location privacy of the users, while localization on the user's device forces the localization provider to disclose the details of the system, e.g., sophisticated classification models. The authors show how secure two-party computation can...

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  • White Papers // Oct 2014

    Integrating Run-Time Observations and Design Component Models for Cloud System Analysis

    Run-time models have been proven beneficial in the past for predicting upcoming quality flaws in cloud applications. Observation approaches relate measurements to executed code whereas prediction models oriented towards design components are commonly applied to reflect reconfigurations in the cloud. Levels of abstraction differ between code observations and these prediction...

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  • White Papers // Oct 2014

    Eco-Reports in Clouds

    In this paper, the authors discuss the issues arising from the need of presenting to the user information about the environmental impact of their applications in a cloud environment. Several aspects have to be considered: to make aware the users of the energy consumption and environmental impact of their applications,...

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  • White Papers // Oct 2014

    Eco-Efficient Cloud Resource Monitoring and Analysis

    In this paper, the authors present an enhanced monitoring approach considering the infrastructure of providers' sites and the Virtual Machines (VMs) hosted on physical nodes. It considers the GAMES and the OPTIMIS projects that were both developing methods for energy-aware resource usage. This paper presents an approach for monitoring cloud...

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  • White Papers // Oct 2014

    On Developing Open Source MDE Tools: Our Eclipse Stories and Lessons Learned

    Tool development has always been a fundamental activity of software engineering. Now-a-days, open source is changing the way this is done in many organizations. Traditional ways of doing things are progressively enhanced or even sometimes replaced by new organizational schemes, benefiting as much as possible from the properties of Open...

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  • White Papers // Oct 2014

    On Static and Dynamic Analysis of UML and OCL Transformation Models

    This contribution discusses model transformations in the form of transformation models that connect a source and a target meta-model. The transformation model is statically analyzed within a UML and OCL tool by giving each constraint an individual representation in the underlying class diagram by highlighting the employed model elements. The...

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  • White Papers // Oct 2014

    HybridRank : A Hybrid Content-Based Approach to Mobile Game Recommendations

    The massive number of mobile games available necessitates a technique to help the consumer find the right game at the right time. This paper introduces HybridRank, a novel hybrid algorithm to deliver recommendations for mobile games. This technique is based on a personalized random walk approach, with the incorporation of...

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  • White Papers // Oct 2014

    A Hybrid Strategy for Privacy-Preserving Recommendations for Mobile Shopping

    To calculate recommendations, recommender systems collect and store huge amounts of users' personal data such as preferences, interaction behavior, or demographic information. If these data are used for other purposes or get into the wrong hands, the privacy of the users can be compromised. Thus, service providers are confronted with...

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  • White Papers // Oct 2014

    Towards Testing Model Transformation Chains Using Precondition Construction in Algebraic Graph Transformation

    Complex model-based tools such as code generators are typically designed as chains of model transformations taking as input a model of a software application and transforming it through several intermediate steps and representations. The complexity of intermediate models is such that testing is more conveniently done on the integrated chain,...

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  • White Papers // Sep 2014

    Analytical Modeling of the IEEE 802.11e EDCA Network with Contention Free Burst

    Contention Free Burst (CFB) is a promising burst transmission scheme defined in the IEEE 802.11e Medium Access Control (MAC) protocol to achieve differentiated Quality of Service (QoS) and improve the utilization of the wireless scarce bandwidth. Although modeling and performance analysis of the IEEE 802.11e network have attracted tremendous research...

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  • White Papers // Sep 2014

    Derivation of a Queuing Network Model for Structured P2P Architectures

    Peer-To-Peer (P2P) networks have using commonly used for tasks such as file sharing or file distribution, and for building distributed applications in large scale network. Their performance measures are generally based on simulation methods software such as NS-2, P2PSim, OpenNet, etc. Hence, the absence of a validation of the simulation...

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  • White Papers // Sep 2014

    Applying Data Fragmentation in IEEE 802.15.4: Modeling and Analysis Under Unsaturated Traffic

    The IEEE 802.15.4 standard, which is developed for low rate applications, offers low latency and energy consumption for wireless sensor networks. The use of the standardized slotted Carrier Sense Multiple Access (CSMA/CA), as a channel access mechanism, can, however, lead to wastage of the bandwidth utilization and an additional transmission...

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  • White Papers // Sep 2014

    Mapping OCL Constraints Into CTL-Like Logic and SML for UML Validation

    The UML (Unified Modeling Language) graphical models miss providing some pertinent elements of specification as constraints over objects and operations. To fill this lack, OCL (Object Constraint Language) has been developed by IBM and integrated to UML as a modern and formal modeling language, which is easy to learn and...

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  • White Papers // Sep 2014

    Cross-Layer Energy-Aware Protocol for Wireless Sensor Networks

    The resource limited nature of WSNs requires that protocols implemented on these networks be energy-efficient, scalable and distributed. In this paper, the authors present a novel combined routing and MAC protocol. The protocol achieves energy efficiency by minimizing signaling overhead through stateless routing decisions that are made at the receiver...

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  • White Papers // Sep 2014

    Comparison of Routing Protocols in Wireless Sensor Networks

    Several routing protocols have been proposed to maximize the sensor networks lifetime. However, most of these solutions try to find an energy efficient path and don't account for energy consumption balancing in sensor network. This usually leads to network partitioning. The aim of this paper is to evaluate, analyze and...

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  • White Papers // Sep 2014

    Fairness Improvement of MAC in Wireless Ad Hoc Networks

    There are many Medium Access Control (MAC) protocols proposed to achieve fairness in presence of hidden and/or exposed nodes. In a general approach to address the problem of fairness is proposed. This approach defines a fairness index and the goal is to minimize this fairness index to achieve fairness. In...

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  • White Papers // Sep 2014

    Model-Checking Cloud Systems Using BigMC

    Cloud computing is a promising concept in the IT evolution that has increasingly attracted attention from both industry and academic sectors. However, it has introduced new security problems and obstacles. Since formal methods provide a reliable mathematical basis giving rise to safely analyzable and easily verifiable models, this paper, the...

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  • White Papers // Sep 2014

    Coping with Spoofed PS-Poll Based DoS Attack in IEEE 802.11 Networks

    IEEE 802.11 networks are particularly vulnerable to DoS (Denial of Service) attacks targeting the network availability. In this paper, the authors focus on the PS-Poll based DoS attack, where the attacker spoofs the polling frame on behalf of the client in order to discard the client's buffered packets at the...

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  • White Papers // Sep 2014

    Graph Clustering Evaluation Metrics as Software Metrics

    Graph Clustering Evaluation (GCE) metrics quantify the quality of clusters obtained by graph clustering (community detection) algorithms. In this paper, the authors argue that GCE metrics can be applied on graph representations of software systems in order to evaluate the degree of cohesiveness of software entities. In contrast to widely...

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  • White Papers // Sep 2014

    Feature Models at Run Time: Feature Middleware for Multi-Tenant SaaS Applications

    Software Product Line Engineering (SPLE) techniques revolve around a central variability model which in many cases is a feature model that documents the logical capabilities of the system as features and the variability relationships between them. In more traditional SPLE, this feature model is a result of domain analysis and...

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  • White Papers // Sep 2014

    Approaches for Test Case Generation From UML Diagrams

    Model Based Testing (MBT) is an important approach with many advantages that can reduce the cost and increase the effectiveness and quality of a testing procedure. In MBT, test cases can be derived from different models, also from the popularly used UML diagrams. Different UML diagrams include various important pieces...

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  • White Papers // Jun 2012

    Performance Evaluation of Channel Access Protocols in Overlapping ECMA-368 Wireless Personal Area Networks

    Medium Access Control (MAC) protocols for Wireless Local Area Networks (WLANs) as well as Wireless Personal Area Networks (WPANs) like Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) are known to provide stable distributed channel access for multiple users. The wide acceptance of wireless systems operating in licensed-exempt frequencies demands...

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  • White Papers // Jun 2012

    Cell Spectral Efficiency Optimization in Relay Enhanced Cells

    The broad acceptance of Smartphones results in increasing capacity demands for mobile radio networks. Decode-and-Forward (DF)-Relay Stations (RSs) are promising to improve Cell Spectral Efficiency (CSE) and to better meet the capacity demands. In this paper, the authors investigate the potential of DF-RSs combined with a pico Base Station (BS)...

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  • White Papers // Feb 2011

    Analytical Evaluation of an IMT-Advanced Compliant LTE System Level Simulator

    LTE-Advanced (LTE-A) proposed by the 3rd Generation Partnership Project (3GPP) has been accepted by the International Telecommunication Union (ITU) in 2010 as an IMT-Advanced (IMT-A) compliant 4G mobile radio system. As part of this application 3GPP has provided LTE-A system level simulation results for cell spectral efficiency and cell edge...

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  • White Papers // Feb 2011

    Performance Analysis of a Framework for Multi-Interfaced Service Level Agreements on Mobile Devices

    Today, the service computing research is focusing on the ubiquitous and on-the-move availability of Internet applications as cloud services. As a result, the mobility is rapidly becoming an important requirement of the future. In addition to that, the integration of mobile and service computing domains enables the existing mobile devices...

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  • White Papers // Sep 2010

    A Correlation-Based MIMO Performance Model for the System Level Analysis on MAC Layer

    IMT-Advanced systems are currently in their evaluation phase. Due to the complexity of all the integrated algorithms and the multidimensional variability of the wireless channels a system evaluation is not easy and only very few large enterprises have the manpower to construct software to simulate all relevant effects. Traditionally the...

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  • White Papers // Oct 2010

    A Framework for Multi-Interfaced Service Level Agreements on Mobile Devices

    Today, the service computing research is focusing on providing efficient solutions to the challenges of the future internet applications. The major difference that is created by these applications is their ubiquitous on-the-move availability as cloud services. This means that the mobility is rapidly becoming a fundamental requirement of the future....

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  • White Papers // Sep 2010

    On Increasing the Spectral Efficiency More Than 100% by User-in-the-Control-Loop

    OFDMA has become the key technology for future cellular wireless networks like the IMT-Advanced systems IEEE 802.16m and 3GPP LTE-A. The advantage of allowing different modulation & coding schemes (PhyModes) adaptively for each radio resource is at the same time a new disadvantage because the performance is now distance-dependent from...

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  • White Papers // Aug 2010

    Interference Aware Scheduling for Ultra Wideband Networks

    Wireless Personal Area Networks (WPANs) are used for a wide variety of applications. Earlier WPANs, like Bluetooth, offer data rates only for low rate communication. Now-a-days, consumer electronic devices have high demands on communication systems, e.g. for high definition video transmission. Users expect future WPANs to act like wired systems...

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  • White Papers // Jul 2010

    The Resource-Oriented Mobile Web Server for Long-Lived Services

    The web servers are globally accepted as the backbone of the Internet. The researchers in the area of the enterprise computing have studied, analyzed and implemented several architectures to optimize the performance of the large-scale web servers. However, due to the convergence of the IT and the mobile communication domains,...

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  • White Papers // Sep 2010

    Uplink Capacity Analysis of OFDMA Based Cellular Networks with Reuse-1

    OFDMA based cellular radio networks aim to operate as close as possible to frequency reuse distance of one, where the whole spectrum would be available in every cell. Modern systems are able to adjust parameters such as transmission power, modulation, and coding separately for each frequency sub-channel on a very...

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  • White Papers // Jun 2010

    QoS and Flow Management for Future Multi-Hop Mobile Radio Networks

    Mobile radio networks of the IMT-Advanced systems family promise ubiquitous broadband access and high area coverage, with rates of several 100 Mb/s. The authors claim to guarantee QoS support in terms of low delay and guaranteed throughput. However, with the availability of flat rate plans and bandwidth-hungry applications of future...

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  • White Papers // Jun 2010

    System Level Performance Evaluation of LTE with MIMO and Relays in Reuse-1 IMT-Advanced Scenarios

    Cellular radio systems of the next generation will have to comply with the IMT-Advanced guidelines. Advanced radio techniques must be integrated into wireless systems to achieve the high spectral efficiency numbers required. Multiple antenna techniques such as MIMO are beneficial in regions of high SINR and low spatial stream correlation....

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  • White Papers // Mar 2012

    Evaluation and Improvement of VoIP Capacity for LTE

    LTE-Advanced (LTE-A) proposed by the 3rd Generation Partnership Project (3GPP) has been accepted by the International Telecommunication Union (ITU) in 2010 as an IMT-Advanced (IMT-A) compliant 4G mobile radio system. Besides high spectral efficiency for data services, LTE-A had to prove its capability to support a large number of voice...

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  • White Papers // May 2011

    Total Optimisation of a Media-Streaming Wireless Terminal: Energy-Efficient Link Adaptation Under Higher-Layer Criteria

    It has long been recognized that a wireless communication system can be more efficient if link-layer parameters such as modulation order, symbol rate and packet size, are (adaptively) optimized. A common optimizing criterion is to maximize spectral efficiency (bits per second per Hertz (bps/Hertz)) subject to a very low bit-error...

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  • White Papers // Jul 2011

    Analytical Evaluation of LTE Uplink Performance in the IMT-Advanced Indoor Hotspot Scenario

    LTE-Advanced (LTE-A) proposed by the 3rd Generation Partnership Project (3GPP) has been accepted by the International Telecommunication Union (ITU) in 2010 as an IMT-Advanced (IMT-A) compliant 4G mobile radio system. As part of this application 3GPP has provided LTE-A system level simulation results for cell spectral efficiency and cell edge...

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  • White Papers // Feb 2011

    Credit-Based Flow Control for Multihop Wireless Networks and Stochastic Petri Nets Analysis

    As the increase of data traffic is expected to grow faster than wireless capacity, dealing with congestion is unavoidable in the future. The capacity imbalance between wired and wireless links leaves a bottleneck on the wireless link while traffic keeps coming in through the bigger pipe. In current systems, the...

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  • White Papers // May 2009

    On Flow Management for Future Multi-Hop Mobile Radio Networks

    Next generation mobile radio networks of IMT-Advanced systems family will offer ubiquitous broadband high area coverage, at up to 1GBit/s in cities and 100MBit/s in rural areas and QoS support in terms of throughput and low delay. Candidate technologies like 3GPP-LTE, WiMAX, as well as the WINNER system design are...

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  • White Papers // Aug 2009

    Capacity Analysis and Improvement for Coexisting IEEE 802.16 Systems in Unlicensed Spectrum

    Today spectrum demand for wireless communication is tremendous and even keeps growing. In contrast, there are no blank spots in the spectrum map. Additional spectrum opportunities are available in unlicensed bands and so-called non-exclusively licensed bands which are currently made available. This non-exclusive spectrum can be exploited whenever a license...

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  • White Papers // Aug 2009

    A Hybrid Solution for Vehicular Communications

    Wireless Access in Vehicular Environments (WAVE) and Universal Mobile Telecommunication System (UMTS) are two technologies that can be used for vehicular communication. WAVE realizes Car-To-X (C2X) communication with WLAN based ad-hoc networks of vehicles and roadside infrastructure. UMTS is a state-of-the-art technology for mobile communication and offers a cellular infrastructure...

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  • White Papers // May 2009

    OpenWNS - Open Wireless Network Simulator

    This paper presents the open Wireless Network Simulator (openWNS). This simulation tool was developed in the last 5 years at the department of Communication Networks (ComNets) at RWTH Aachen University and has been released as open source software recently. The openWNS is a dynamic event driven system level simulation platform...

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  • White Papers // Feb 2011

    Upper Bound Cell Spectral Efficiency of IMT-Advanced Scenarios

    The International Telecommunication Union - Radio Group (ITU-R) has established a set of requirements to be met by candidate systems to be accepted as International Mobile Telecommunications - Advanced (IMT-A) compliant and has set up evaluation guidelines to asses compliance. In this paper, a numerical model following these guidelines is...

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  • White Papers // Mar 2012

    Decode-and-Forward Relay Placement for Maximum Cell Spectral Efficiency

    To meet increasing capacity demands in mobile radio networks Decode-and-Forward (DF) Relay Stations (RSs) have been proposed. In this paper, the authors investigate the potential of low power DF-RSs to increase the Cell Spectral Efficiency (CSE) under rate fair scheduling. They introduce a model based on simulated-annealing to find optimal...

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  • White Papers // Oct 2012

    First Survey Results of Quantified User Behavior in User-in-the-Loop Scenarios for Sustainable Wireless Networks

    Traffic in mobile radio networks is expected to continue to increase by 100% per year. This imposes a big challenge for future generations (4G and 5G) of access technologies which were previously dimensioned for over-provisioning especially in the busy hours. Recent forecasts hint that this assumption and approach will not...

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  • White Papers // Oct 2012

    Quantified User Behavior in User-in-the-Loop Spatially and Demand Controlled Cellular Systems

    User-centric services are a growing concern. While the digital society definitely needs better Quality-of-Experience (QoE) for the user, the applications on smart mobile devices will continue to raise traffic in mobile radio networks by almost 100% per annum. Future generations of access technologies are challenged by this and the conventional...

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  • White Papers // May 2012

    Modeling and Performance Evaluation for Mobile Ricean MIMO Channels

    The authors propose a general channel model for mobile Ricean Multiple-Input Multiple-Output (MIMO) channels, which is characterized by parameters that are readily obtainable from measurements. To this end, a moment-based channel decomposition is derived. For the case of statistical Channel State Information (CSI) at the Transmitter (TX) and instantaneous CSI...

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  • White Papers // May 2012

    Mesh-DHT: A Locality-Based Distributed Look-Up Structure for Wireless Mesh Networks

    Distributed Hash Tables (DHTs) offer an elegant and fully distributed solution for reliably storing and retrieving data. Wireless Mesh Networks (WMNs) envision a fully decentralized fashion, and as such require efficient decentralized mechanisms for service discovery, mobility support and data storage and retrieval. Hence, DHTs and WMNs seem to complement...

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  • White Papers // May 2012

    On the Performance of Cellular Network Deployments in TV Whitespaces

    In this paper, the authors analyze the prospects of deploying a cellular network in the TV whitespaces. They study the challenges of planning for a large-scale transmitter network that is constrained by an interference-to-primary regulation. For this purpose they derive a novel methodology to maximize the downlink capacity at the...

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  • White Papers // May 2012

    Wi-Fi, But Not on Steroids: Performance Analysis of a Wi-Fi-Like Network Operating in TVWS Under Realistic Conditions

    The recent decisions by regulators in the USA and UK to open up unused portions of UHF spectrum for secondary use have been met with keen interest in using these TV White Spaces (TVWS) for providing broadband services through Wi-Fi-like connectivity. Amid the ensuing media hype about "Wi-Fi on steroids",...

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  • White Papers // May 2012

    Shadow Fading Correlations With Compressive Sensing: Prediction Accuracy

    The cross-correlation between shadowing components in wireless communications has important implications for wireless systems. The new cooperative and cognitive communications methods can exploit these correlations, if the statistical properties of shadowing correlations were known in particular radio environment under the consideration. The statistical large scale models have higher uncertainty compared...

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  • White Papers // Jan 2013

    MR-DSJ: Distance-Based Self-Join for Large-Scale Vector Data Analysis with MapReduce

    Data analytics gets faced with huge and tremendously increasing amounts of data for which MapReduce provides a very convenient and effective distributed programming model. Various algorithms already support massive data analysis on computer clusters but, in particular, distance-based similarity self-joins lack efficient solutions for large vector data sets though they...

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  • White Papers // Oct 2012

    Rate Selection Analysis Under Semi-Persistent Scheduling in LTE Networks

    Upcoming LTE networks have basically two different modes for scheduling data in the down-link by the base station. Dynamic scheduling brings the advantage of exploiting instantaneous channel state information while it puts on the other hand a significant burden on the system in terms of overhead and computation requirements. Especially...

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  • White Papers // Oct 2012

    The Outage Performance of Realtime Transmission in Multiple Asynchronous Relays Enhanced OFDM System

    This paper considers the outage performance of multiple relays transmission in Orthogonal Frequency Division Multiplexing (OFDM) systems. Relaying has been suggested in general to improve the reliability of wireless systems significantly and is therefore a candidate for wireless industrial communication systems that need to meet tough latency and outage requirements....

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  • White Papers // Jan 2013

    On the Outage Probability and Effective Capacity of Multiple Decode-and-Forward Relay System

    This paper investigates the quality-of-service performance of multiple decode-and-forward relay system. In particular, the authors study the outage probability and effective capacity performance of the system based on average channel gain. First, a closed-form expression of outage probability is derived which is more concise than the previous work. Second, they...

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  • White Papers // Aug 2012

    Distributed TV Spectrum Allocation for Cognitive Cellular Network Under Game Theoretical Framework

    This paper proposes efficient schemes for wireless cellular base stations to utilize TV white spectrum (such base stations referred to as white base stations - WBS), so that WBSes can provide good services to their end terminals without violating the incumbent TV services. In particular, the authors consider two complementary...

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  • White Papers // Apr 2012

    Multi-Level Parallelism for Time-And Cost-Efficient Parallel Discrete Event Simulation on GPUs

    Developing complex technical systems requires a systematic exploration of the given design space in order to identify optimal system configurations. However, studying the effects and interactions of even a small number of system parameters often requires an extensive number of simulation runs. This in turn results in excessive runtime demands...

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  • White Papers // Mar 2012

    Know Thy Simulation Model: Analyzing Event Interactions for Probabilistic Synchronization in Parallel Simulations

    Efficiently scheduling and synchronizing parallel event execution constitutes the fundamental challenge in parallel discrete event simulation. Existing synchronization algorithms typically do not analyze event interactions within the simulation model - mainly to minimize runtime overhead and complexity. However, the authors argue that disregarding event interactions results in a lack of...

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  • White Papers // May 2011

    Predicting Runtime Performance Bounds of Expanded Parallel Discrete Event Simulations

    Predicting and analyzing runtime performance characteristics is a vital step in the development process of parallel discrete event simulations. For instance, model developers need to identify and eliminate performance bottlenecks within a simulation model in order to derive a model structure that aids parallel execution. Similarly, developers of parallel simulation...

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  • White Papers // May 2010

    A Game-Theoretic Approach to Routing Under Adversarial Conditions

    The authors present a game-theoretic framework for modeling and solving routing problems in dynamically changing networks. The model covers the aspects of reactivity and non-termination, and it is motivated by quality-of-service provisioning in cognitive radio networks where data transmissions are interfered by primary systems. More precisely, they propose an infinite...

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  • White Papers // Apr 2012

    Intelligibility Assessment of a System for Artifical Bandwidth Extension of Telephone Speech

    For the present study, the extension from the 0.3 - 3.4 kHz range towards higher audio frequencies was considered. The employed ABWE algorithm follows the source-filter model of speech production. Techniques for Artificial BandWidth Extension (ABWE) aim to extend the limited audio bandwidth of current narrowband telephone systems (0.3 -...

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  • White Papers // Aug 2011

    Rate-Compatible LDPC Codes using Optimized Dummy Bit Insertion

    Much attention has been paid to Low-Density Parity-Check (LDPC) codes since their rediscovery by MacKay. They belong to the most powerful channel coding techniques known today and have a broad range of applications. In wireless communication systems it is desirable to be able to adjust the code rate of the...

    Provided By RWSoftware