Deutsche Telekom

Displaying 1-18 of 18 results

  • White Papers // May 2012

    Same But Different? - Using Speech Signal Features for Comparing Conversational VoIP Quality Studies

    In this paper, the authors demonstrate how speech signal features can be used to detect and explain differences in human to human conversation tests. To this end, they compare the results of two conversational VoIP quality experiments designed to quantify the impact of network delay on perceived speech quality. Both...

    Provided By Deutsche Telekom

  • White Papers // Apr 2011

    OFRewind: Enabling Record and Replay Troubleshooting for Networks

    Debugging operational networks can be a daunting task, due to their size, distributed state, and the presence of black box components such as commercial routers and switches, which are poorly instrumentable and only coarsely configurable. The debugging tool set available to administrators is limited, and provides only aggregated statistics (SNMP),...

    Provided By Deutsche Telekom

  • White Papers // Mar 2011

    Online Strategies for Intra and Inter Provider Service Migration in Virtual Networks

    Network virtualization allows one to build dynamic distributed systems in which resources can be dynamically allocated at locations where they are most useful. In order to fully exploit the benefits of this new technology, protocols need to be devised which react efficiently to changes in the demand. This paper argues...

    Provided By Deutsche Telekom

  • White Papers // Jan 2011

    Competitive and Deterministic Embeddings of Virtual Networks

    Network virtualization is a paradigm that allows for flexible and efficient allocation of the resources among multiple Virtual Networks (VNets). In this paper, the authors deal with the problem of embedding dynamically arriving VNet requests. They describe a generic algorithm for the online VNet embedding problem and analyze its competitive...

    Provided By Deutsche Telekom

  • White Papers // Jan 2011

    Intelligent Selection of Access Nodes for Multi-Interface Mobile Terminals

    This paper tackles the problems of intelligent interface selection for mobile terminals connected to Fixed & Mobile Converged (FMC) network and equipped with multiple network interfaces of different access technologies. Selection mechanisms that can be found in today's networks are analyzed and their drawbacks are estimated. A new selection policy...

    Provided By Deutsche Telekom

  • White Papers // Oct 2010

    TCPSpeaker: Clean and Dirty Sides of the Same Slate

    The performance and fairness problems of TCP in 802.11 multi-hop Wireless Mesh Networks (WMN). Approaches to solve them fall roughly into two different categories: those which maintain legacy TCP compatibility, and clean-slate protocols which fundamentally redefine WMN transport, breaking TCP compatibility. Clean-slate approaches such as block-switched and cross-layer transport protocols...

    Provided By Deutsche Telekom

  • White Papers // Oct 2010

    Energy Conservation in Multi-Tenant Networks Through Power Virtualization

    In the service-centric Internet, multiple virtual services (tenants) are over-layed on top of the same infrastructure (both in wide-area networks and in datacenter networks). The authors propose conserving energy, in this setting, by virtualizing network power consumed by each tenant, feeding back that information to the tenant, and incentivizing the...

    Provided By Deutsche Telekom

  • White Papers // Sep 2010

    Can the Production Network Be the Testbed?

    A persistent problem in computer network research is validation. When deciding how to evaluate a new feature or bug fix, a researcher or operator must trade-off realism (in terms of scale, actual user traffic, real equipment) and cost (larger scale costs more money, real user traffic likely requires downtime, and...

    Provided By Deutsche Telekom

  • White Papers // Sep 2010

    Design of a Configurable Wireless Network Testbed With Live Traffic

    Testbeds have become standard tools for performance evaluation in wireless networks as they allow for evaluation with realistic wireless propagation and interference conditions, hardware constraints and timing requirements. However, in most testbeds, traffic and user mobility is generated by either using synthetic load generation tools, or replaying traffic traces. Evaluations...

    Provided By Deutsche Telekom

  • White Papers // May 2010

    LENS: LEveraging Anti-Social Networking Against Spam

    Spam is still an open problem from the network operator's perspective. The common state-of-the-art strategy to place filters against spam is at the recipient's edge. Although, this strategy largely solves the spam problem from the user's perspective - false positives/negatives may still exist - it cannot prevent spam from traversing...

    Provided By Deutsche Telekom

  • White Papers // Feb 2010

    Fair Performance Comparison Between CQI- And CSI-Based MU-MIMO for the LTE Downlink

    The authors compare the performance of the downlink of a 3GPP UTRAN Long Term Evolution (LTE) system with MultiUser (MU) Multiple Input Multiple Output (MIMO) support and Channel State Information (CSI) feedback to a standard MUMIMO LTE system utilizing Channel Quality Indicator (CQI) feedback only. For the latter case, they...

    Provided By Deutsche Telekom

  • White Papers // Feb 2010

    A Nash Equilibrium Analysis for Interference Coupled Wireless Systems

    This paper studies the properties of Nash equilibrium for non-cooperative games in interference coupled wireless systems, where it serves as an incentive-compatible solution concept and an operating point. A broad class of non-cooperative power control games played among the users of the wireless system is defined based on a general...

    Provided By Deutsche Telekom

  • White Papers // Sep 2009

    Enabling Secure Secret Sharing in Distributed Online Social Networks

    The authors study a new application of threshold-based secret sharing in a Distributed Online Social Network (DOSN), where users need a means to back up and recover their private keys in a network of untrusted servers. Using a simple threshold-based secret sharing in such an environment is insufficiently secured since...

    Provided By Deutsche Telekom

  • White Papers // Jul 2009

    Real World Routing Using Virtual World Information

    In this paper, the authors propose to leverage social graphs from Online Social Networks (OSN) to improve the forwarding efficiency of mobile networks, more particularly Delay Tolerant Networks (DTN). They extract community structures from three popular OSNs, Flickr, LiveJournal, and YouTube, and quantify the clustering features of each network at...

    Provided By Deutsche Telekom

  • White Papers // Jul 2009

    Distributed and Robust Rate Control for Communication Networks

    Contemporary networks are distributed, complex, and heterogeneous. Ensuring an efficient, fair, and incentive-compatible allocation of bandwidth among their users constitutes a challenging and multi-faceted research problem. This paper presents three control and game-theoretic approaches that address rate control problems from different perspectives. First, a non-cooperative rate control game focusing on...

    Provided By Deutsche Telekom

  • White Papers // Jun 2009

    Adaptive Wireless Services for Augmented Environments

    This paper presents a system that combines mobile services, ubiquitous computing, and augmented reality concepts in order to bring the kind of information-rich environment, which is currently limited to computer screens, to the physical world. This objective is achieved by constructing an architecture based on existing wireless Web application and...

    Provided By Deutsche Telekom

  • White Papers // May 2009

    Delay-Tolerant Social Networking

    To address privacy concerns in current online social networks, the authors previously proposed to use a peer-to-peer infrastructure and encryption, thereby recreating the features of online social networks in a distributed, provider-less, community-driven, and privacy-preserving way. Once the functionality is distributed, social networks are no longer dependent on Internet connectivity...

    Provided By Deutsche Telekom

  • White Papers // Dec 2008

    A Case for P2P Infrastructure for Social Networks - Opportunities & Challenges

    Online Social Networks like Facebook, MySpace, Xing, etc. have become extremely popular. Yet they have some limitations that the authors want to overcome for a next generation of social networks: privacy concerns and requirements of Internet connectivity, both of which are due to web-based applications on a central site whose...

    Provided By Deutsche Telekom

  • White Papers // May 2010

    LENS: LEveraging Anti-Social Networking Against Spam

    Spam is still an open problem from the network operator's perspective. The common state-of-the-art strategy to place filters against spam is at the recipient's edge. Although, this strategy largely solves the spam problem from the user's perspective - false positives/negatives may still exist - it cannot prevent spam from traversing...

    Provided By Deutsche Telekom

  • White Papers // Oct 2010

    Energy Conservation in Multi-Tenant Networks Through Power Virtualization

    In the service-centric Internet, multiple virtual services (tenants) are over-layed on top of the same infrastructure (both in wide-area networks and in datacenter networks). The authors propose conserving energy, in this setting, by virtualizing network power consumed by each tenant, feeding back that information to the tenant, and incentivizing the...

    Provided By Deutsche Telekom

  • White Papers // Mar 2011

    Online Strategies for Intra and Inter Provider Service Migration in Virtual Networks

    Network virtualization allows one to build dynamic distributed systems in which resources can be dynamically allocated at locations where they are most useful. In order to fully exploit the benefits of this new technology, protocols need to be devised which react efficiently to changes in the demand. This paper argues...

    Provided By Deutsche Telekom

  • White Papers // Apr 2011

    OFRewind: Enabling Record and Replay Troubleshooting for Networks

    Debugging operational networks can be a daunting task, due to their size, distributed state, and the presence of black box components such as commercial routers and switches, which are poorly instrumentable and only coarsely configurable. The debugging tool set available to administrators is limited, and provides only aggregated statistics (SNMP),...

    Provided By Deutsche Telekom

  • White Papers // Sep 2010

    Can the Production Network Be the Testbed?

    A persistent problem in computer network research is validation. When deciding how to evaluate a new feature or bug fix, a researcher or operator must trade-off realism (in terms of scale, actual user traffic, real equipment) and cost (larger scale costs more money, real user traffic likely requires downtime, and...

    Provided By Deutsche Telekom

  • White Papers // Jan 2011

    Competitive and Deterministic Embeddings of Virtual Networks

    Network virtualization is a paradigm that allows for flexible and efficient allocation of the resources among multiple Virtual Networks (VNets). In this paper, the authors deal with the problem of embedding dynamically arriving VNet requests. They describe a generic algorithm for the online VNet embedding problem and analyze its competitive...

    Provided By Deutsche Telekom

  • White Papers // Jan 2011

    Intelligent Selection of Access Nodes for Multi-Interface Mobile Terminals

    This paper tackles the problems of intelligent interface selection for mobile terminals connected to Fixed & Mobile Converged (FMC) network and equipped with multiple network interfaces of different access technologies. Selection mechanisms that can be found in today's networks are analyzed and their drawbacks are estimated. A new selection policy...

    Provided By Deutsche Telekom

  • White Papers // Sep 2010

    Design of a Configurable Wireless Network Testbed With Live Traffic

    Testbeds have become standard tools for performance evaluation in wireless networks as they allow for evaluation with realistic wireless propagation and interference conditions, hardware constraints and timing requirements. However, in most testbeds, traffic and user mobility is generated by either using synthetic load generation tools, or replaying traffic traces. Evaluations...

    Provided By Deutsche Telekom

  • White Papers // Oct 2010

    TCPSpeaker: Clean and Dirty Sides of the Same Slate

    The performance and fairness problems of TCP in 802.11 multi-hop Wireless Mesh Networks (WMN). Approaches to solve them fall roughly into two different categories: those which maintain legacy TCP compatibility, and clean-slate protocols which fundamentally redefine WMN transport, breaking TCP compatibility. Clean-slate approaches such as block-switched and cross-layer transport protocols...

    Provided By Deutsche Telekom

  • White Papers // Feb 2010

    A Nash Equilibrium Analysis for Interference Coupled Wireless Systems

    This paper studies the properties of Nash equilibrium for non-cooperative games in interference coupled wireless systems, where it serves as an incentive-compatible solution concept and an operating point. A broad class of non-cooperative power control games played among the users of the wireless system is defined based on a general...

    Provided By Deutsche Telekom

  • White Papers // Jun 2009

    Adaptive Wireless Services for Augmented Environments

    This paper presents a system that combines mobile services, ubiquitous computing, and augmented reality concepts in order to bring the kind of information-rich environment, which is currently limited to computer screens, to the physical world. This objective is achieved by constructing an architecture based on existing wireless Web application and...

    Provided By Deutsche Telekom

  • White Papers // Jul 2009

    Distributed and Robust Rate Control for Communication Networks

    Contemporary networks are distributed, complex, and heterogeneous. Ensuring an efficient, fair, and incentive-compatible allocation of bandwidth among their users constitutes a challenging and multi-faceted research problem. This paper presents three control and game-theoretic approaches that address rate control problems from different perspectives. First, a non-cooperative rate control game focusing on...

    Provided By Deutsche Telekom

  • White Papers // Dec 2008

    A Case for P2P Infrastructure for Social Networks - Opportunities & Challenges

    Online Social Networks like Facebook, MySpace, Xing, etc. have become extremely popular. Yet they have some limitations that the authors want to overcome for a next generation of social networks: privacy concerns and requirements of Internet connectivity, both of which are due to web-based applications on a central site whose...

    Provided By Deutsche Telekom

  • White Papers // Sep 2009

    Enabling Secure Secret Sharing in Distributed Online Social Networks

    The authors study a new application of threshold-based secret sharing in a Distributed Online Social Network (DOSN), where users need a means to back up and recover their private keys in a network of untrusted servers. Using a simple threshold-based secret sharing in such an environment is insufficiently secured since...

    Provided By Deutsche Telekom

  • White Papers // May 2009

    Delay-Tolerant Social Networking

    To address privacy concerns in current online social networks, the authors previously proposed to use a peer-to-peer infrastructure and encryption, thereby recreating the features of online social networks in a distributed, provider-less, community-driven, and privacy-preserving way. Once the functionality is distributed, social networks are no longer dependent on Internet connectivity...

    Provided By Deutsche Telekom

  • White Papers // Jul 2009

    Real World Routing Using Virtual World Information

    In this paper, the authors propose to leverage social graphs from Online Social Networks (OSN) to improve the forwarding efficiency of mobile networks, more particularly Delay Tolerant Networks (DTN). They extract community structures from three popular OSNs, Flickr, LiveJournal, and YouTube, and quantify the clustering features of each network at...

    Provided By Deutsche Telekom

  • White Papers // Feb 2010

    Fair Performance Comparison Between CQI- And CSI-Based MU-MIMO for the LTE Downlink

    The authors compare the performance of the downlink of a 3GPP UTRAN Long Term Evolution (LTE) system with MultiUser (MU) Multiple Input Multiple Output (MIMO) support and Channel State Information (CSI) feedback to a standard MUMIMO LTE system utilizing Channel Quality Indicator (CQI) feedback only. For the latter case, they...

    Provided By Deutsche Telekom

  • White Papers // May 2012

    Same But Different? - Using Speech Signal Features for Comparing Conversational VoIP Quality Studies

    In this paper, the authors demonstrate how speech signal features can be used to detect and explain differences in human to human conversation tests. To this end, they compare the results of two conversational VoIP quality experiments designed to quantify the impact of network delay on perceived speech quality. Both...

    Provided By Deutsche Telekom