RWSoftware

Displaying 1-40 of 287 results

  • 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

    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

    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

    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

    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

    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

    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

    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

    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

    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

    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

    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

    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

    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

    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

    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

    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

    Model-Driven Engineering Meets the Platform-as-a-Service Model

    Organizations who want to migrate their applications to Platform-as-a-Service (PaaS) environments have a lot of PaaS vendors to choose from and many PaaS offerings within them. At the PaaS abstraction level within the cloud service model, each vendor offers many different configurations to meet the specific organization's criteria to migrate...

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  • White Papers // Feb 2010

    Performance Analysis of Reuse Partitioning Techniques in OFDMA Based Cellular Radio Networks

    Reuse partitioning is a useful method for mitigating Co-Channel Interference (CCI) in Orthogonal Frequency Division Multiple Access (OFDMA) based cellular environments. In this paper, theoretical analysis of a series of reuse partitioning approaches is carried out, which contains the well-known Soft Frequency Reuse (SFR) scheme, the novel Enhanced Fractional Frequency...

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  • White Papers // Feb 2010

    A Closed Loop Control Model Separating Resource and Packet Scheduling in Multihop Cellular Networks

    4G cellular systems and the IMT Advanced candidates will provide broadband wireless access with QoS. Especially in multihop configurations of these systems the base station controls resources centrally while relays can take over a part of the responsibility on the second hop. To make this work on layer two, scheduling...

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  • White Papers // Oct 2009

    Frequency Reuse Techniques for Attaining Both Coverage and High Spectral Efficiency in OFDMA Cellular Systems

    Inter-Cell Interference (ICI) is always a big obstacle to attain wide area coverage and high spectral efficiency in cellular systems. In this paper, the authors make a study of two well-known frequency reuse approaches, namely the Soft Frequency Reuse (SFR) scheme and the Incremental Frequency Reuse (IFR) scheme. Both of...

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  • White Papers // Dec 2010

    Prototypical Implementation of a Service Oriented Wireless Sensor Networks Application

    The Wireless Sensor Networks (WSN) environments are increasingly becoming intelligent with the rapid boost in the capabilities of sensor nodes. The Sun Small Programmable Object Technology (SPOT) platform offers a high-end sensing device in terms of processing, memory and battery configurations compared to the other existing in the community. Within...

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  • White Papers // Jun 2010

    Spectrum Load Smoothing in IEEE 802.16 Systems

    Today's framework for radio spectrum regulation and spectrum usage is undergoing fundamental changes. In the face of scarce radio resources, regulators, industry, and the research community are initiating promising approaches towards a more flexible spectrum usage, as for example cognitive radios for dynamic spectrum assignment. In this paper an intelligent...

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  • White Papers // Nov 2009

    Mobile Web Services in Health Care and Sensor Networks

    The Wireless Sensor Networks (WSN) environments are increasingly becoming intelligent with the rapid boost in the capabilities of sensor nodes. The sun Small Programmable Object Technology (SPOT) platform offers a high-end sensing device in terms of processing, memory and battery configurations compared to other existing in the community. Within the...

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  • White Papers // Oct 2009

    Enhanced Fractional Frequency Reuse to Increase Capacity of OFDMA Systems

    Inter-Cell Interference (ICI) mitigation is always a big challenge issue in cellular systems. In this paper, the authors propose an Enhanced Fractional Frequency Reuse (EFFR) scheme combined with power allocation and an interference-aware reuse mechanism to achieve not only ICI limitation at cell edge but also enhancement of overall cell...

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  • White Papers // Sep 2009

    Model-Based Radio and Channel Assignment in IEEE 802.11 Wireless Mesh Networks

    Local area wireless networks based on IEEE 802.11 have a cellular topology: stations associate to one of several access points, which are connected using a wired backbone. As connectivity is only possible close to the access points, a dense infrastructure is needed, resulting in high costs. A Wireless Mesh Network...

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  • White Papers // Jul 2009

    4G Cross-Layer Closed Loop Control Scheduling

    Packet and resource scheduling are two distinct tasks inside the medium access control layer of a wireless system of the fourth generation. Packet scheduling is the determination of the ordering of packets among competing connections or users, where the server itself is not specified. Resource Scheduling (RS) is the determination...

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  • White Papers // May 2009

    Adaptive Power Control for 4G OFDMA Systems on Frequency Selective Fading Channels

    Future cellular radio systems aim at maximizing the spectral efficiency. OFDMA radio resources are the scarce good with their dimensions bandwidth, time and space. Due to frequency selective fading the effective path-loss varies in all dimensions. Adaptive algorithms are available which allocate the best modulation and coding scheme depending on...

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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 // Jun 2009

    Enabling High Performance Mobile Web Services Provisioning

    The TeleCommunication (TelCo) and Information Technology (IT) domains are converging at their intersection to provide vast variety of efficiently accessible services to the consumers. Especially in mobile communication domain, a vital factor that can affect the performance of any mobile application is the resource constraint nature of mobile devices with...

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  • White Papers // Jul 2009

    Analysis of a TDMA Coexistence Approach for IEEE 802.16 Systems

    Today's radio frequency regulation is undergoing fundamental changes. There is a high demand for radio frequency spectrum for data communication but no blank spots in the frequency assignments plan. Under the approach of coexistence and cognitive radio multiple systems can share spectrum in unlicensed bands. Additionally non-exclusive licensing allowing secondary...

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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 // Jul 2009

    Coordination Across Base Stations for Effective Control of Space Division Multiple Access Enhanced IEEE 802.16m Systems

    In recent years, smart antenna technologies are of ever-increasing interest to boost the capacity of existing and future wireless systems. Several standards support these techniques such as the wireless metropolitan area network IEEE 802.16 (WiMAX) and IMT-Advanced candidates. In applying smart antenna beam-forming and Space Division Multiple Access (SDMA) techniques,...

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  • White Papers // Jun 2009

    An IEEE 802.11 Model for the Planning of Wireless Mesh Networks

    Service-area specific optimization is a necessity for large-scale wireless networks. For this task, a model to estimate the quality of a radio network configuration is required. In the case of cellular radio networks, much work exists on models for Radio Network Planning (RNP). This work cannot be applied to optimize...

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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 // Apr 2009

    IEEE 802.16 Coexistence Through Regular Channel Occupation

    Today's radio frequency regulation is undergoing fundamental changes. There is a high demand for radio frequency spectrum for data communication but no blank spots in the frequency assignments plan. Under the approach of coexistence and cognitive radio, spectrum is made available to systems if a license holder is not using...

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  • White Papers // Jun 2009

    A Service-Oriented Approach for In-Network Computations in Wireless Networks

    The concept of Mobile Web Services (Mob-WS) is catching pace within research communities due to rapid classification of mobile devices enabling pervasive environments. Beside consumer oriented use cases, another aspect of utilizing the potential of Mob-WS is to use them as computation resources within a wireless network. Such Mob-WS are...

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  • White Papers // Aug 2008

    Architecture for Consuming Long-Lived Mobile Web Services Over Multiple Transport Protocols

    The concept of Mobile Web Services (Mob-WS) is catching pace within research communities due to rapid classification of mobile devices enabling pervasive environments. A web service based middleware for mobile applications is a promising platform to accelerate the application development for mobile systems. This paper introduces a middleware for time...

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  • White Papers // Jun 2009

    A Multi-Mode MAC Protocol Integrating FDD and TDD for Next Generation Multi-Hop Mobile Radio Networks

    There are two basic duplexing schemes for present and future mobile radio networks, frequency-division duplexing and time-division duplexing. In general each of these methods has its benefits and drawbacks. However, both schemes are more or less appropriate under consideration of the communication environment. In future mobile radio systems typical wireless...

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  • White Papers // Jun 2009

    Theoretical Analysis of Saturation Throughput in MU-DCF

    In this paper, the calculation of saturation throughput for previously proposed Multi-User - Distributed Coordination Function (MU-DCF) is presented. MU-DCF is an IEEE 802.11 based protocol that supports Multi-User (MU)-Multiple Input-Multiple Output (MIMO) transmissions. The analysis is for two extreme case scenarios: Access Point (AP) downlink in a hotspot scenario,...

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  • White Papers // Jun 2009

    An FDD Multihop Cellular Network for 3GPP-LTE

    The future cellular radio networks like 3G-LTE are based on an OFDMA physical layer. The duplex scheme is preferably Frequency Division (FDD) because of its advantages in long range. Huge area coverage in a cost-efficient way is important problem for the early deployment. Time after time the demand in densely...

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  • White Papers // Mar 2009

    The Influence of Subchannel Diversity on the Performance of OFDMA Systems Based on IEEE 802.16

    The performance of a mobile radio system based on OFDMA is determined by the type of mapping of logical sub-channels, which are allocated for data transmissions, onto the frequency channel. The mapping scheme affects the diversity both within and between the OFDMA sub-channels. This paper provides a performance comparison of...

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  • White Papers // Jun 2009

    Opportunistic Wireless Internet Access in Vehicular Environments Using Enhanced WAVE Devices

    The emerging Car-To-Car communication (C2C) technology, known as Wireless Access in Vehicular Environments (WAVE), enables vehicles on the roadway to communicate with each other and with the roadside infrastructure. In addition to safety-relevant services, drivers may also need internet access through C2C communications for infotainment services and car maintenance services,...

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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 // Jun 2010

    Frame Delay Distribution Analysis of IEEE 802.11 Networks Using Signal Flow Graphs

    Frame delay variance in CSMA/CA networks is large. Wireless applications may require both, limited mean delay and limited delay jitter. These parameters can be derived easily from Cumulative Distribution Function (CDF) of frame delay. This paper applies Signal Flow Graphs (SFGs) to calculate the CDF of frame delay in IEEE...

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  • White Papers // Dec 2009

    Region Coordination Across Space Division Multiple Access Enhanced Base Stations in IEEE 802.16m Systems

    In recent years, smart antenna technologies are of ever-increasing interest to boost the capacity of future wireless systems. Several standards support these techniques such as the Wireless Metropolitan Area Network IEEE 802.16 (WiMAX) and IMT-Advanced candidates. In applying smart antenna beamforming and Space Division Multiple Access (SDMA) techniques, adaptive antennas...

    Provided By RWSoftware

  • White Papers // Apr 2010

    How Bad Is Interference in IEEE 802.16e Systems?

    This paper presents a performance model for dynamic resource allocation in cellular deployments of IEEE 802.16e-like systems. More specifically, the authors derive a framework which allows to quantify the number of VoIP calls that can be supported in downlink of such systems purely based on the average SINR per terminal....

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  • White Papers // Dec 2009

    The K - Constrained Bipartite Matching Problem: Approximation Algorithms and Applications to Wireless Networks

    In communication networks, resource assignment problems appear in several different settings. These problems are often modeled by a maximum weight matching problem in bipartite graphs and efficient matching algorithms are well known. In several applications, the corresponding matching problem has to be solved many times in a row as the...

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  • White Papers // Apr 2010

    Considering Microelectronic Trends in Advanced Wireless System Design

    Wireless communication system design has been a booming topic since the shift into the digital era in the 1990s. In the same period of time, microelectronic technologies have reached new paradigm points as they were going deeper into the sub-micron area. This paper gives an overview of these emerging constraints...

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  • White Papers // Sep 2012

    Energy Efficiency of Network-Based Acoustic Echo Control in Mobile Radio

    In this paper, the authors investigate the energy efficiency of network-based Acoustic Echo Control (AEC). Usually, AEC is implemented in the mobile terminal. Due to the limited resources of the mobile terminal in terms of the battery, computational capacity and memory, the complexity of the AEC algorithm has to be...

    Provided By RWSoftware