RWTH Aachen University

Displaying 1-40 of 67 results

  • White Papers // Aug 2012

    A Rendezvous Protocol with the Heterogeneous Spectrum Availability Analysis for Cognitive Radio Ad Hoc Networks

    In Cognitive Radio Ad Hoc Networks (CRANs) a frequently changing environment, licensed holders channel occupancy and heterogeneous spectrum availability result in a need of on-demand searching for a control traffic channel by CR users in order to be able to initiate a communication. A RenDezVous (RDV) is therefore a new...

    Provided By RWTH Aachen University

  • White Papers // Jul 2012

    Quorum Systems Towards an Asynchronous Communication in Cognitive Radio Networks

    This paper studies Quorum Systems (QS) and relevant properties, originally and widely used in the scope of operating systems and currently being applied in wireless communications. The objective of this paper is threefold. This paper gives a comprehensive guidance on QSs and their usage. And it shows that QS properties...

    Provided By RWTH Aachen University

  • White Papers // Jun 2012

    Torus Quorum System and Difference Set-Based Rendezvous in Cognitive Radio Ad Hoc Networks

    In Cognitive Radio Ad Hoc Networks (CRANs) a frequently changing environment and Primary Users channel occupancy result in a need of the searching for a common control channel by Secondary Users in order to be able to initiate a communication. A RenDezvous (RDV) is therefore a new challenge, not encountered...

    Provided By RWTH Aachen University

  • White Papers // May 2012

    Hackers in Your Pocket: A Survey of Smartphone Security Across Platforms

    In the past research on smart phone operating system security has been scattered over blog posts and other non-archival publications. Over the last 5 years with advent of Android, iOS and Windows Phone 7, an increasing amount of research has also been published in the academic sphere on individual security...

    Provided By RWTH Aachen University

  • White Papers // Mar 2012

    Dynamic Packet Scheduling in Wireless Networks

    The authors consider protocols that serve communication requests arising over time in a wireless network that is subject to interference. Unlike previous approaches, they take the geometry of the network and power control into account, both allowing to increase the network's performance significantly. They introduce a stochastic and an adversarial...

    Provided By RWTH Aachen University

  • White Papers // Jan 2012

    Introducing SOR: SSH-Based Onion Routing

    Traditional low-latency anonymization techniques apply non-standardized, complex, and often even proprietary protocols. Apart from poor performance, the high development effort leads to the existence of at most one single implementation. This in turn increases the risk of creating so-called software monocultures, where failures in the single implementation can compromise the...

    Provided By RWTH Aachen University

  • White Papers // Jan 2012

    Generalised Link-Layer Optimisation: Application and Performance Evaluation

    A wireless communication system work more efficiently if link-layer parameters such as modulation order, symbol rate and packet size are (adaptively) optimised. A common criterion is to maximise spectral efficiency subject to a very low bit-error constraint. But for systems equipped with strong error detection and a selective packet re-transmission...

    Provided By RWTH Aachen University

  • White Papers // Dec 2011

    Femtocell Downlink Power Control Based on Radio Environment Maps

    The paper investigates the use of Radio Environment Maps (REMs) as a tool for Interference Management (IM) in two-tier cellular networks comprising macro- and femto-cells. The REMs are databases that provide, through different instances distributed over network elements, a variety of network- and user-related context information for improving IM and...

    Provided By RWTH Aachen University

  • White Papers // Oct 2011

    Exploring Opportunistic Access Techniques Using Stochastic Models: Dynamic Spectrum Access Without Sensing

    In this paper, the authors explore the use of stochastic approaches for opportunistic access based on models of primary user activity. They focus in particular on a scenario where the secondary user does not perform traditional sensing at all, but relies only on statistical information of primary transmissions. Using techniques...

    Provided By RWTH Aachen University

  • White Papers // Sep 2011

    Lightweight Hidden Services

    Hidden Services (HS) are mechanisms designed to provide network services while preserving anonymity for the identity of the server. Besides protecting the identity of the server, hidden services help to resist censorship, are resistant against distributed DoS attacks, and allow server functionality even if the service provider does not own...

    Provided By RWTH Aachen University

  • White Papers // Sep 2011

    Enabling Run-Time Utility-Based Optimization Through Generic Interfaces in Wireless Networks

    In this paper, the authors address the use of utility-based optimization in wireless networks. Their optimization approach is enabled by well-defined, technology- and platform-independent generic interfaces. The latter provide an abstract and unified representation of data and services available from the protocol stack, ranging from old legacy protocols to newer...

    Provided By RWTH Aachen University

  • White Papers // Aug 2011

    Optimization and Evaluation of a Multimedia Streaming Service on Hybrid Telco Cloud

    With recent developments in cloud computing, a paradigm shift from rather static deployment of resources to more dynamic, on-demand practices means more flexibility and better utilization of resources. This demands new ways to efficiently configure networks. In this paper, the authors will characterize a class of competitive cloud services that...

    Provided By RWTH Aachen University

  • White Papers // Jul 2011

    Mobile Cloud Computing: A Comparison of Application Models

    Cloud computing is an emerging concept combining many fields of computing. The foundation of cloud computing is the delivery of services, software and processing capacity over the Internet, reducing cost, increasing storage, automating systems, decoupling of service delivery from underlying technology, and providing flexibility and mobility of information. However, the...

    Provided By RWTH Aachen University

  • White Papers // Jul 2011

    Transmit Power Control for Secondary Use in Environments With Correlated Shadowing

    In this paper, the authors propose a general model to estimate the maximum allowed transmit power of a secondary node based on the measured signal from the primary transmitter that is willing to share its downlink spectrum. The transmit power should satisfy primary constraints related to the minimum required Signal...

    Provided By RWTH Aachen University

  • White Papers // Jul 2011

    Green Communications by Demand Shaping and User-in-the-Loop Tariff-Based Control

    The new field of green communications can be divided into energy-efficient communications equipment or using information and communication technology to improve the world to become more energy aware. Mobile data traffic and utility energy consumption have a lot in common. There is a limited supply due to limited resources, and...

    Provided By RWTH Aachen University

  • White Papers // Jun 2011

    A Multi-Objective Approach for Data Collection in Wireless Sensor Networks

    Wireless Sensors Networks (WSNs) are deployed to collect huge amounts of data from the environment. This produced data has to be delivered through sensor's wireless interface using multi-hop communications toward a sink. The position of the sink impacts the performance of the wireless sensor network regarding delay and energy consumption...

    Provided By RWTH Aachen University

  • White Papers // May 2011

    Security and Privacy Implications of URL Shortening Services

    URL shortening services replace long URLs with shorter ones and subsequently redirect all requests for the shortened URL to the original long URL. In this paper, the authors discuss and empirically analyze security and privacy risks caused by the use of URL shortening services. They empirically determine the most popular...

    Provided By RWTH Aachen University

  • White Papers // May 2011

    Cost Evaluation Of Credit Risk Securitization In The Electricity Industry: Credit Default Acceptance Vs. Margining Costs

    Institutions such as the European Commission (EC) are currently seeking to increase the transparency of the derivatives markets. This course of action includes in particular the installation of a centralized clearing entity and with this the obligation to clear all relevant financial derivatives. Besides the expected securitization of the financial...

    Provided By RWTH Aachen University

  • White Papers // Apr 2011

    Fair and Privacy-Preserving Multi-Party Protocols for Reconciling Ordered Input Sets

    In this paper, the authors introduce the first protocols for multi-party, privacy-preserving, fair reconciliation of ordered sets. The contributions are twofold. First, they show that it is possible to extend the round-based construction for fair, two-party privacy-preserving reconciliation of ordered sets to multiple parties using a multi-party privacy-preserving set intersection...

    Provided By RWTH Aachen University

  • White Papers // Apr 2011

    Secure Resolution of End-Host Identifiers for Mobile Clients

    Many efforts of the network research community focus on the introduction of a new identifier to relieve the IP address from its dual role of end-host identifier and routable locator. This identifier-locator split introduces a new identifier between human readable domain names and routable IP addresses. Mapping between identifiers and...

    Provided By RWTH Aachen University

  • White Papers // Feb 2011

    Multihop Wireless Channel Models Suitable for Stochastic Petri Nets and Markov State Analysis

    In this paper the system analysis of modern wireless systems is simplified by providing simple yet powerful models for the wireless channel in the environment of higher layer abstract system descriptions with generalized Stochastic Petri Nets (SPN). This modeling approach is capable of deriving performance metrics in terms of packet...

    Provided By RWTH Aachen University

  • White Papers // Jan 2011

    Transfer Function Synthesis Without Quantifier Elimination

    Recently it has been shown how transfer functions for linear template constraints can be derived for bit-vector programs by operating over propositional Boolean formulae. The drawback of this method is that it relies on existential quantifier elimination, which induces a computational bottleneck. The contribution of this paper is a novel...

    Provided By RWTH Aachen University

  • White Papers // Oct 2010

    Using Cognitive Radio Principles for Wireless Resource Management in Home Networking

    The demand for higher data rates, capacity and better quality-of-service is constantly growing for home networks. Therefore, there is a pressing need for efficient use of wireless network resources. In this paper, the application of cognitive radio principles that enable network nodes to characterize their environment and control their resources...

    Provided By RWTH Aachen University

  • White Papers // Sep 2010

    An Implementation of Cognitive Resource Management on LTE Platform

    In this paper, the authors describe an LTE based demonstrator of the Universal Link Layer API (ULLA) and Cognitive Resource Manager (CRM) modules that are developed in ARAGORN project. The demonstrated LTE system comprises one LTE TDD eNode B and one User Equipment (UE). They first introduce ULLA and CRM...

    Provided By RWTH Aachen University

  • White Papers // Sep 2010

    Enabling Secondary Access Through Robust Primary User Channel Assignment

    A common concept to mitigate the effects of spectrum scarcity is to allow opportunistic Dynamic Spectrum Access (DSA) to licensed frequency bands. In this paper, the license holder may experience a decrease in the performance of its network. For cellular networks this may lead to unwanted coverage holes at locations...

    Provided By RWTH Aachen University

  • White Papers // Jul 2010

    Parallel Processing of Data From Very Large-Scale Wireless Sensor Networks

    In this paper the authors explore the problems of storing and reasoning about data collected from very large-scale Wireless Sensor Networks (WSNs). Potential worldwide deployment of WSNs for, e.g., environmental monitoring purposes could yield data in amounts of petabytes each year. Distributed database solutions such as BigTable and Hadoop are...

    Provided By RWTH Aachen University

  • White Papers // Jul 2010

    Distributed Storage and Parallel Processing in Large-Scale Wireless Sensor Networks

    In this paper, the authors explore the problems of storing and reasoning about data collected from very large-scale Wireless Sensor Networks (WSNs). Potential worldwide deployment of WSNs for, e.g., environmental monitoring purposes could yield data in amounts of petabytes each year. Distributed database solutions such as BigTable and Hadoop are...

    Provided By RWTH Aachen University

  • White Papers // Jun 2010

    Expanding the Event Horizon in Parallelized Network Simulations

    The simulation models of wireless networks rapidly increase in complexity to accurately model wireless channel characteristics and the properties of advanced transmission technologies. Such detailed models typically lead to a high computational load per simulation event that accumulates to extensive simulation runtimes. Reducing runtimes through parallelization is challenging since it...

    Provided By RWTH Aachen University

  • White Papers // Jun 2010

    Demo Abstract: A Decentralized MAC Protocol for Opportunistic Spectrum Access in Cognitive Wireless Networks

    Cognitive MACs are becoming a reality for efficiently utilizing the constrained spectral resources. The spectrum opportunities are volatile and often difficult to predict. Furthermore, infrastructure based coordinated spectrum sharing is not a viable option for some applications and spectrum bands. Therefore, dynamic and decentralized medium access becomes highly desirable. The...

    Provided By RWTH Aachen University

  • White Papers // May 2010

    Mobile Access to MPEG-7 Based Multimedia Services

    Multimedia information systems have been developed into service-ware. With the paradigms of web services, Service Oriented Architectures (SOA), and Web 2.0 widgets, multimedia has become truly ubiquitous. However, interoperability, scalability, reliability and security are arising challenges at mobile multimedia service development. This paper focuses on the analysis, design, development and...

    Provided By RWTH Aachen University

  • White Papers // Apr 2010

    Placing Regenerators in Optical Networks to Satisfy Multiple Sets of Requests

    The placement of regenerators in optical networks has become an active area of research during the last years. Given a set of light-paths in a network G and a positive integer d, regenerators must be placed in such a way that in any light-path there are no more than d...

    Provided By RWTH Aachen University

  • White Papers // Apr 2010

    Evaluation of Quality of Experience for Video Streaming Over Dynamic Spectrum Access Systems

    In this paper, the authors study the problem of quantifying the value of spectrum opportunities to secondary users in Dynamic Spectrum Access (DSA) systems. They especially focus on estimating the impact of key channel parameters, namely the activity patterns of the primary users on the expected quality of experience for...

    Provided By RWTH Aachen University

  • White Papers // Feb 2010

    Impact of Primary User Activity Patterns on Spatial Spectrum Reuse Opportunities

    Activity patterns of primary users have significant influence on the opportunities for secondary use of spectrum. In this paper, the authors explore this impact in terms of spatial spectrum reuse opportunities. More specifically, they model the primary user activity as a Semi-Markov ON/OFF process with varying distributions of holding times...

    Provided By RWTH Aachen University

  • White Papers // Feb 2010

    Dynamic TinyOS: Modular and Transparent Incremental Code-Updates for Sensor Networks

    Long-term deployments of sensor networks in physically inaccessible environments make remote re-programmability of sensor nodes a necessity. Ranging from full image replacement to virtual machines, a variety of mechanisms exist today to deploy new software or to fix bugs in deployed systems. However, TinyOS - the current state of the...

    Provided By RWTH Aachen University

  • White Papers // Feb 2010

    Cognitive Radio for Home Networking

    Cognitive Radios have emerged as one of the most promising methods to increase wireless system efficiency through dynamic spectrum access combined with cross-layer optimization methods. Most of the research prototypes and demonstrations have so far focused on either general platforms or scenarios that are predominantly taken from military or emergency...

    Provided By RWTH Aachen University

  • White Papers // Feb 2010

    Location-Based Adaptive Detection Threshold for Dynamic Spectrum Access

    In this paper, the authors propose a heuristic algorithm that exploits additional information, such as related to geo-location and frequency allocation, that can be in general known by a secondary network willing to opportunistically access the spectrum allocated to a primary network. The algorithm aims at finding the maximum allowed...

    Provided By RWTH Aachen University

  • White Papers // Jan 2010

    Promoting Power to a First Class Metric in Network Simulations

    Accurate prediction of energy consumption early in the design process is essential to efficiently optimize algorithms and protocols. However, despite energy efficiency gathering significant attention in networking research, limited effort has been invested in providing requisite evaluation tools and models. Hence, developers demand powerful evaluation tools to assist them in...

    Provided By RWTH Aachen University

  • White Papers // Jan 2010

    Secure Roaming and Handover Procedures in Wireless Access Networks

    A growing number of wireless technologies and providers, as well as users increasing need and desire to be connected and reachable at all times, call for solutions that enable interoperation between providers and technologies. Roaming procedures enable wireless access in areas that are covered by network providers with which the...

    Provided By RWTH Aachen University

  • White Papers // Dec 2009

    Polytool: Polynomial Interpretations as a Basis for Termination Analysis of Logic Programs

    The authors' goal is to study the feasibility of porting termination analysis techniques developed for one programming paradigm to another paradigm. In this paper, they show how to adapt termination analysis techniques based on polynomial interpretations - very well known in the context of Term Rewrite Systems (TRSs) - to...

    Provided By RWTH Aachen University

  • White Papers // Dec 2009

    Enabling Resource-Oriented Mobile Web Server for Short-Lived Services

    Mobile Web Services (MobWSs) are a promising technology for the integration of Information Technology (IT) and TeleCommunication (TelCo) domains. The advancements in mobile communication and device technology, in terms of software and hardware, have revolutionized the focus of research and industry to investigate mobile service provisioning platforms and architectures. In...

    Provided By RWTH Aachen University

  • White Papers // Jul 2012

    Quorum Systems Towards an Asynchronous Communication in Cognitive Radio Networks

    This paper studies Quorum Systems (QS) and relevant properties, originally and widely used in the scope of operating systems and currently being applied in wireless communications. The objective of this paper is threefold. This paper gives a comprehensive guidance on QSs and their usage. And it shows that QS properties...

    Provided By RWTH Aachen University

  • White Papers // Jun 2001

    Monitoring Public Perception of Medical Products by Automatically Assigning Metadata to Online Discussion Group Postings

    This paper describes an ongoing project whose goal is to create a digital library of public perceptions of over-the-counter and prescription drugs. The Web has created an unprecedented opportunity to mine and organize public perceptions and experiences with medications. There are hundreds of chat rooms devoted to medical conditions and...

    Provided By RWTH Aachen University

  • White Papers // Mar 2009

    Can Cloud Computing Reach the TOP500?

    Computing as a utility has reached the mainstream. Scientists can now rent time on large commercial clusters through several vendors. The cloud computing model provides flexible support for "Pay as you go" systems. In addition to no upfront investment in large clusters or supercomputers, such systems incur no maintenance costs....

    Provided By RWTH Aachen University

  • White Papers // Jul 2009

    Flexible Multi-Dimensional Visualization of Process Enactment Data

    The management of development processes is a challenging task and needs adequate tool support. In the course of a development project, many different engineering and management processes are enacted and have to be controlled. The management data has an inherently multidimensional character. Most project and process management systems fail to...

    Provided By RWTH Aachen University

  • White Papers // Jan 2010

    Secure Roaming and Handover Procedures in Wireless Access Networks

    A growing number of wireless technologies and providers, as well as users increasing need and desire to be connected and reachable at all times, call for solutions that enable interoperation between providers and technologies. Roaming procedures enable wireless access in areas that are covered by network providers with which the...

    Provided By RWTH Aachen University

  • White Papers // Jun 2009

    Demo Abstract: Spectrum Agile Medium Access Control Protocol for Wireless Sensor Networks

    In this demonstration paper the authors describe a low-power spectrum agile medium access control protocol for wireless sensor networks. The protocol allows sensor nodes to dynamically select an interference minimal channel for data communication. It does not pose any synchronization restrictions on the nodes and effectively handles the dynamics of...

    Provided By RWTH Aachen University

  • White Papers // Jul 2010

    Parallel Processing of Data From Very Large-Scale Wireless Sensor Networks

    In this paper the authors explore the problems of storing and reasoning about data collected from very large-scale Wireless Sensor Networks (WSNs). Potential worldwide deployment of WSNs for, e.g., environmental monitoring purposes could yield data in amounts of petabytes each year. Distributed database solutions such as BigTable and Hadoop are...

    Provided By RWTH Aachen University

  • White Papers // Oct 2008

    WSIM: A Software Platform to Simulate All-Optical Security Operations

    Network throughput rates increase every day in contrast to electronic chip processing speed and electronic I/O. Today's firewalls operate by using traditional electronic circuits just like any common PC. However, performing these operations in a fast fiber optics network on the scale of 40Gbps is impossible. In this paper, the...

    Provided By RWTH Aachen University

  • White Papers // Jul 2009

    QMetric - A Metric Tool Suite for the Evaluation of Software Process Data

    Configuration and change request management systems offer valuable information for the assessment of process quality characteristics. The definition of appropriate metrics that address the information needs of an organization is an intricate task. The authors present the QMetric tool suite which provides a general infrastructure for specifying metrics, relating them...

    Provided By RWTH Aachen University

  • White Papers // Apr 2011

    Fair and Privacy-Preserving Multi-Party Protocols for Reconciling Ordered Input Sets

    In this paper, the authors introduce the first protocols for multi-party, privacy-preserving, fair reconciliation of ordered sets. The contributions are twofold. First, they show that it is possible to extend the round-based construction for fair, two-party privacy-preserving reconciliation of ordered sets to multiple parties using a multi-party privacy-preserving set intersection...

    Provided By RWTH Aachen University

  • White Papers // Jul 2010

    Distributed Storage and Parallel Processing in Large-Scale Wireless Sensor Networks

    In this paper, the authors explore the problems of storing and reasoning about data collected from very large-scale Wireless Sensor Networks (WSNs). Potential worldwide deployment of WSNs for, e.g., environmental monitoring purposes could yield data in amounts of petabytes each year. Distributed database solutions such as BigTable and Hadoop are...

    Provided By RWTH Aachen University

  • White Papers // Oct 2010

    Using Cognitive Radio Principles for Wireless Resource Management in Home Networking

    The demand for higher data rates, capacity and better quality-of-service is constantly growing for home networks. Therefore, there is a pressing need for efficient use of wireless network resources. In this paper, the application of cognitive radio principles that enable network nodes to characterize their environment and control their resources...

    Provided By RWTH Aachen University

  • White Papers // Feb 2009

    Spatial Statistics of Spectrum Usage: From Measurements to Spectrum Models

    Several measurement studies have found a large amount of underutilized radio spectrum. More flexible regulation employing Dynamic Spectrum Access (DSA) has been proposed as solution to this problem. The analysis of several aspects of DSA systems, e.g., cooperative sensing, requires good spatial models of spectrum usage. However, only very focused...

    Provided By RWTH Aachen University

  • White Papers // Sep 2010

    Enabling Secondary Access Through Robust Primary User Channel Assignment

    A common concept to mitigate the effects of spectrum scarcity is to allow opportunistic Dynamic Spectrum Access (DSA) to licensed frequency bands. In this paper, the license holder may experience a decrease in the performance of its network. For cellular networks this may lead to unwanted coverage holes at locations...

    Provided By RWTH Aachen University

  • White Papers // Sep 2010

    An Implementation of Cognitive Resource Management on LTE Platform

    In this paper, the authors describe an LTE based demonstrator of the Universal Link Layer API (ULLA) and Cognitive Resource Manager (CRM) modules that are developed in ARAGORN project. The demonstrated LTE system comprises one LTE TDD eNode B and one User Equipment (UE). They first introduce ULLA and CRM...

    Provided By RWTH Aachen University

  • White Papers // Aug 2009

    Exploring Simulated Annealing and Graphical Models for Optimization in Cognitive Wireless Networks

    In this paper, the authors discuss the design of optimization algorithms for Cognitive Wireless Networks (CWNs). Maximizing the perceived network performance towards applications by selecting appropriate protocols and carrying out cross-layer optimization on the resulting stack is a key functionality of any CWN. They take a "Black box" approach to...

    Provided By RWTH Aachen University

  • White Papers // May 2009

    Modelling Primary System Activity in Dynamic Spectrum Access Networks by Aggregated ON/OFF-Processes

    Accurate modeling of primary system activity is key to reliable performance evaluation of Dynamic Spectrum Access (DSA) technologies. Measurements on spectrum use show that in some cases the lengths of the vacant periods in a given frequency band can be correlated, a feature commonly used semi-Markov ON/OFF-models cannot reproduce. In...

    Provided By RWTH Aachen University

  • White Papers // Jun 2009

    A Common Application Requirement Interface for Cognitive Wireless Networks

    The authors discuss the design of a Common APplication Requirement Interface (CAPRI) for cognitive wireless networks. Applications can use CAPRI to express optimization goals and policies they expect the network to follow, which can subsequently be used by cognitive engines in their optimization processes. They believe that CAPRI design fills...

    Provided By RWTH Aachen University

  • White Papers // Jan 2009

    Lessons Learned From an Extensive Spectrum Occupancy Measurement Campaign and a Stochastic Duty Cycle Model

    Several measurement campaigns have shown that numerous spectrum bands are vacant although licenses have been issued by the regulatory agencies. Dynamic Spectrum Access (DSA) has been proposed in order to alleviate this problem and increase the spectral utilization. In this paper, the authors present the spectrum measurement setup and discuss...

    Provided By RWTH Aachen University

  • White Papers // Jan 2009

    Measuring Complexity and Predictability in Networks With Multiscale Entropy Analysis

    The authors propose to use multiscale entropy analysis in characterisation of network traffic and spectrum usage. They show that with such analysis one can quantify complexity and predictability of measured traces in widely varying timescales. They also explicitly compare the results from entropy analysis to classical characterisations of scaling and...

    Provided By RWTH Aachen University

  • White Papers // Jul 2009

    The EIFFEL Approach Towards Visions for a Future Networked Society

    The Internet was not designed to be a critical part of the economy - but it has become exactly that. In fact, it has become a critical infrastructure for the overall society in developed countries. There are many questions today on how the Internet will or should develop in the...

    Provided By RWTH Aachen University

  • White Papers // May 2012

    Hackers in Your Pocket: A Survey of Smartphone Security Across Platforms

    In the past research on smart phone operating system security has been scattered over blog posts and other non-archival publications. Over the last 5 years with advent of Android, iOS and Windows Phone 7, an increasing amount of research has also been published in the academic sphere on individual security...

    Provided By RWTH Aachen University

  • White Papers // May 2009

    Enhancing Cognitive Radios With Spatial Statistics: From Radio Environment Maps to Topology Engine

    Radio environment maps are a promising architectural concept for storing environmental information for use in cognitive wireless networks. However, if not applied carefully their use can lead to large amounts of measurement data communicated over wireless links, causing substantial overhead. The authors propose enhancing the basic radio environment map concept...

    Provided By RWTH Aachen University

  • White Papers // Mar 2009

    A Case for Generic Interfaces in Cognitive Radio Networks

    Cognitive wireless networks are envisioned as a solution for intelligent ubiquitous networks that are capable of adapting to the dynamic environment through programmable radio devices. Each functional module and protocol accomplishes such learning by observing the various environmental, networking and application related parameters and adapts its behavior to improve the...

    Provided By RWTH Aachen University

  • White Papers // Nov 2009

    Low-Latency Linux Drivers for Ethernet Over High-Speed Networks

    Now-a-days, high computing demands are often tackled by clusters of single computers, each of which is basically an assembly of a growing number of CPU cores and main memory, also called a node; these nodes are connected by some kind of communication network. With the growing speed and number of...

    Provided By RWTH Aachen University

  • White Papers // Apr 2010

    Evaluation of Quality of Experience for Video Streaming Over Dynamic Spectrum Access Systems

    In this paper, the authors study the problem of quantifying the value of spectrum opportunities to secondary users in Dynamic Spectrum Access (DSA) systems. They especially focus on estimating the impact of key channel parameters, namely the activity patterns of the primary users on the expected quality of experience for...

    Provided By RWTH Aachen University

  • White Papers // Apr 2011

    Secure Resolution of End-Host Identifiers for Mobile Clients

    Many efforts of the network research community focus on the introduction of a new identifier to relieve the IP address from its dual role of end-host identifier and routable locator. This identifier-locator split introduces a new identifier between human readable domain names and routable IP addresses. Mapping between identifiers and...

    Provided By RWTH Aachen University

  • White Papers // Feb 2010

    Dynamic TinyOS: Modular and Transparent Incremental Code-Updates for Sensor Networks

    Long-term deployments of sensor networks in physically inaccessible environments make remote re-programmability of sensor nodes a necessity. Ranging from full image replacement to virtual machines, a variety of mechanisms exist today to deploy new software or to fix bugs in deployed systems. However, TinyOS - the current state of the...

    Provided By RWTH Aachen University

  • White Papers // Jun 2012

    Torus Quorum System and Difference Set-Based Rendezvous in Cognitive Radio Ad Hoc Networks

    In Cognitive Radio Ad Hoc Networks (CRANs) a frequently changing environment and Primary Users channel occupancy result in a need of the searching for a common control channel by Secondary Users in order to be able to initiate a communication. A RenDezvous (RDV) is therefore a new challenge, not encountered...

    Provided By RWTH Aachen University

  • White Papers // Jun 2010

    Expanding the Event Horizon in Parallelized Network Simulations

    The simulation models of wireless networks rapidly increase in complexity to accurately model wireless channel characteristics and the properties of advanced transmission technologies. Such detailed models typically lead to a high computational load per simulation event that accumulates to extensive simulation runtimes. Reducing runtimes through parallelization is challenging since it...

    Provided By RWTH Aachen University

  • White Papers // Aug 2011

    Optimization and Evaluation of a Multimedia Streaming Service on Hybrid Telco Cloud

    With recent developments in cloud computing, a paradigm shift from rather static deployment of resources to more dynamic, on-demand practices means more flexibility and better utilization of resources. This demands new ways to efficiently configure networks. In this paper, the authors will characterize a class of competitive cloud services that...

    Provided By RWTH Aachen University

  • White Papers // Jun 2010

    Demo Abstract: A Decentralized MAC Protocol for Opportunistic Spectrum Access in Cognitive Wireless Networks

    Cognitive MACs are becoming a reality for efficiently utilizing the constrained spectral resources. The spectrum opportunities are volatile and often difficult to predict. Furthermore, infrastructure based coordinated spectrum sharing is not a viable option for some applications and spectrum bands. Therefore, dynamic and decentralized medium access becomes highly desirable. The...

    Provided By RWTH Aachen University

  • White Papers // May 2010

    Mobile Access to MPEG-7 Based Multimedia Services

    Multimedia information systems have been developed into service-ware. With the paradigms of web services, Service Oriented Architectures (SOA), and Web 2.0 widgets, multimedia has become truly ubiquitous. However, interoperability, scalability, reliability and security are arising challenges at mobile multimedia service development. This paper focuses on the analysis, design, development and...

    Provided By RWTH Aachen University

  • White Papers // Oct 2011

    Exploring Opportunistic Access Techniques Using Stochastic Models: Dynamic Spectrum Access Without Sensing

    In this paper, the authors explore the use of stochastic approaches for opportunistic access based on models of primary user activity. They focus in particular on a scenario where the secondary user does not perform traditional sensing at all, but relies only on statistical information of primary transmissions. Using techniques...

    Provided By RWTH Aachen University

  • White Papers // Jun 2009

    Practical Distributed Channel Selection Protocol for Single-Hop Transmissions in Cognitive Radio Ad Hoc Networks

    In this paper, the authors propose a practical distributed channel selection protocol for cognitive radio ad hoc networks considering single hop transmission. The proposed protocol uses the control channel in order to exchange information concerning the available data channels and also to establish communications. The channel selection is performed based...

    Provided By RWTH Aachen University

  • White Papers // Feb 2010

    Location-Based Adaptive Detection Threshold for Dynamic Spectrum Access

    In this paper, the authors propose a heuristic algorithm that exploits additional information, such as related to geo-location and frequency allocation, that can be in general known by a secondary network willing to opportunistically access the spectrum allocated to a primary network. The algorithm aims at finding the maximum allowed...

    Provided By RWTH Aachen University

  • White Papers // Feb 2010

    Cognitive Radio for Home Networking

    Cognitive Radios have emerged as one of the most promising methods to increase wireless system efficiency through dynamic spectrum access combined with cross-layer optimization methods. Most of the research prototypes and demonstrations have so far focused on either general platforms or scenarios that are predominantly taken from military or emergency...

    Provided By RWTH Aachen University

  • White Papers // Jan 2010

    Promoting Power to a First Class Metric in Network Simulations

    Accurate prediction of energy consumption early in the design process is essential to efficiently optimize algorithms and protocols. However, despite energy efficiency gathering significant attention in networking research, limited effort has been invested in providing requisite evaluation tools and models. Hence, developers demand powerful evaluation tools to assist them in...

    Provided By RWTH Aachen University

  • White Papers // Dec 2011

    Femtocell Downlink Power Control Based on Radio Environment Maps

    The paper investigates the use of Radio Environment Maps (REMs) as a tool for Interference Management (IM) in two-tier cellular networks comprising macro- and femto-cells. The REMs are databases that provide, through different instances distributed over network elements, a variety of network- and user-related context information for improving IM and...

    Provided By RWTH Aachen University

  • White Papers // Sep 2011

    Enabling Run-Time Utility-Based Optimization Through Generic Interfaces in Wireless Networks

    In this paper, the authors address the use of utility-based optimization in wireless networks. Their optimization approach is enabled by well-defined, technology- and platform-independent generic interfaces. The latter provide an abstract and unified representation of data and services available from the protocol stack, ranging from old legacy protocols to newer...

    Provided By RWTH Aachen University