University of Patras

Displaying 1-40 of 46 results

  • White Papers // Jul 2012

    A Performance Study of Fractional Frequency Reuse in OFDMA Networks

    Long Term Evolution (LTE) technology is considered as the most possible candidate for next generation mobile communications. LTE networks offer high capacity and are specified and designed to accommodate small, high performance, power-efficient end-user devices. One limiting factor that influences LTE performance is the interference from neighbor cells, the so...

    Provided By University of Patras

  • White Papers // Jul 2012

    Genetic Optimization for Spectral Efficient Multicasting in LTE Systems

    Past research has proposed the usage of assisting cells with Multimedia Broadcast/Multicast Service (MBMS) over a Single Frequency Network (MBSFN) to increase the Spectral Efficiency (SE) of LTE. In this paper, the authors propose and investigate a method for optimizing the power consumption of the network while retaining an acceptable...

    Provided By University of Patras

  • White Papers // Jun 2012

    Enhancing Reliable Mobile Multicasting With RaptorQ FEC

    A crucial point on the successful deployment of multicast services is the enhanced reliability by means of advanced error control schemes. To this direction Third Generation Partnership Project (3GPP) has standardized exclusively for Multimedia Broadcast/Multicast Services (MBMS) the use of a Forward Error Correction (FEC) mechanism on the application layer...

    Provided By University of Patras

  • White Papers // Mar 2012

    Multilateration: Methods for Clustering Intersection Points for Wireless Sensor Networks Localization With Distance Estimation Error

    In this paper, the authors describe three methods for localizing a wireless sensor network node, using anchor nodes in its neighbourhood, when there is an error in distance estimation present. They use the intersection points of the circles formed with the estimated distances from each anchors and they apply different...

    Provided By University of Patras

  • White Papers // Feb 2012

    Plastic-Based Substrate Integrated Waveguide (SIW) Components and Antennas

    This paper presents the implementation of Substrate Integrated Waveguide (SIW) components and antennas in a PolyEthylene Terephthalate (PET) substrate. PET is a cheap and flexible material, which represents an important candidate for the development of future conformal and wearable wireless systems. The characterization of the electrical properties of the material...

    Provided By University of Patras

  • White Papers // Nov 2011

    A Low-Complexity Resource Allocation Algorithm for MIMO-OFDMA Multicast Systems With Spectrum-Guarantee Provisioning

    This paper studies the important problem of resource allocation for the down-link of Multiple-Input Multiple-Output (MIMO) Multicast Wireless Systems operating over frequency-selective channels. Multi-casting over wireless OFDMA networks is expected to enhance significantly the multimedia access and provide ubiquitous multimedia experience to large number of users, since a sub-carrier is...

    Provided By University of Patras

  • White Papers // Aug 2011

    AL-FEC for Streaming Services Over LTE Systems

    The Third Generation Partnership Project (3GPP), recently introduced the evolution of the Third Generation (3G) cellular networks, the Long Term Evolution (LTE) telecommunication system. A key aspect of LTE specifications is the enhancement of Multimedia Broadcast/Multicast Services (MBMS), where the same content is transmitted to multiple users located in a...

    Provided By University of Patras

  • White Papers // Jun 2011

    Reliable Multicasting Over LTE: A Performance Study

    With the booming of multimedia services, the 3rd Generation Partnership Project (3GPP) has introduced the evolved Multimedia Multicast/Broadcast Service (e-MBMS) feature for LTE systems. The main objective of MBMS is to introduce real broadcast distribution capabilities into cellular systems. This purposed 3GPP to introduce the MBMS over a Single Frequency...

    Provided By University of Patras

  • White Papers // Mar 2011

    Combining MBSFN and PTM Transmission Schemes for Resource Efficiency in LTE Networks

    Long Term Evolution (LTE) systems allow the transmission of rich multimedia services by utilizing the Multimedia Broadcast/Multicast Service (MBMS) over a Single Frequency Network (MBSFN). During MBSFN transmission a time-synchronized common waveform is transmitted from multiple cells. The 3rd Generation Partnership Project (3GPP) has specified that Point-To-Multipoint (PTM) transmission can...

    Provided By University of Patras

  • White Papers // Mar 2011

    Enabling Live Video Streaming Services Realization in Telecommunication Networks Using P2P Technology

    Peer-To-Peer (P2P) systems enjoy wide adoption from internet users. Success of P2P architecture is due to its ability to scale and to organize dynamically the traffic according to the user resources and requests. On the contrary, P2P adoption is constrained in non-real time applications, like content distribution and file sharing....

    Provided By University of Patras

  • White Papers // Feb 2011

    Interference Mitigation Via Joint Detection in a Fading Environment

    This paper considers the detection problem for fading channels in the presence of interference when both the transmitter of interest and the interferers employ practical modulation schemes. It is shown that, for Rayleigh fading, it is possible to obtain symbol error rates that have the same dependence on the received...

    Provided By University of Patras

  • White Papers // Jan 2011

    Wiselib: A Generic Algorithm Library for Heterogeneous Sensor Networks

    One unfortunate consequence of the success story of Wireless Sensor Networks (WSNs) in separate research communities is an ever growing gap between theory and practice. Even though there are an increasing number of algorithmic methods for WSNs, the vast majority has never been tried in practice; conversely, many practical challenges...

    Provided By University of Patras

  • White Papers // Jan 2011

    Longitudinal Analytics on Web Archive Data: It's About Time!

    Organizations like the Internet Archive have been capturing Web contents over decades, building up huge repositories of time-versioned pages. The timestamp annotations and the sheer volume of multi-modal content constitutes a gold mine for analysts of all sorts, across different application areas, from political analysts and marketing agencies to academic...

    Provided By University of Patras

  • White Papers // Dec 2010

    Computational Intelligence Techniques and Agents' Technology in E-Learning Environments

    In this contribution a newly developed e-learning environment is presented, which incorporates Intelligent Agents and Computational Intelligence Techniques. The new e-learning environment is constituted by three parts, the E-learning platform Front-End, the Student Questioner Reasoning and the Student Model Agent. These parts are distributed geographically in dispersed computer servers, with...

    Provided By University of Patras

  • White Papers // Nov 2010

    Experimental Demonstration of an Impairment Aware Network Planning and Operation Tool for Transparent/Translucent Optical Networks

    Core optical networks using reconfigurable optical switches and tunable lasers appear to be on the road towards widespread deployment and could evolve to all-optical mesh networks in the coming future. Considering the impact of physical layer impairments in the planning and operation of all-optical (and translucent) networks is the main...

    Provided By University of Patras

  • White Papers // Oct 2010

    Using Flash Memories as Simo Channels for Extending the Lifetime of Solid-State Drives

    Reliability and I/O performance are the two basic metrics that determine the quality of Solid-State Drives (SSDs), especially in enterprise storage systems. Flash memories, the most popular non-volatile memory used in today's solid-state drives, demonstrate a time-varying behavior in terms of raw bit errors per program/erase cycle. This paper presents...

    Provided By University of Patras

  • White Papers // Aug 2010

    A Quantitative Research On Physicians-Detailers Long-Term Relationships Building, In Prescribed Drug Marketing Contexts

    The presented research is part of a doctoral study, which, among others, investigated a wide array of relationship building constituents and effects that may evolve in the context of a physicians - detailers-pharmaceutical companies' network. Specifically, for the purposes of this paper, the authors select the variables detailer's listening efficacy,...

    Provided By University of Patras

  • White Papers // Jul 2010

    An Approximation Simulator for Designing and Developing Accessible Java Swing Applications

    Failure to determine the requirements for accessibility support in Rich Internet Applications (RIA), and to verify that such support meets the needs of people with disabilities will result in the continued poor or non-existent levels of access for these applications. Developers and designers face a real challenge when implementing software...

    Provided By University of Patras

  • White Papers // Jun 2010

    Coverage-Adaptive Random Walks for Fast Sensory Data Collection

    Random walks in wireless sensor networks can serve as fully local, very simple strategies for sink motion that significantly reduce energy dissipation a lot but increase the latency of data collection. To achieve satisfactory energy-latency trade-offs the sink walks can be made adaptive, depending on network parameters such as density...

    Provided By University of Patras

  • White Papers // May 2010

    The Effect Of Tax Incentives On Investment - Decisions Of Transnational Enterprises (TNEs) In An Integrated World: A Literature Review

    The aim of this paper is to provide a selective survey of both theoretical and empirical literature, concerning the factors, especially tax - incentives, that affect Foreign Direct Investment (FDI) inflows. Nowadays, TransNational Enterprises (TNEs) are major actors in international trade. For this reason, central-governments in OECD countries compete with...

    Provided By University of Patras

  • White Papers // Apr 2010

    Enhancing Service Portability in Upcoming 3G UMTS Networks & Security Aspects

    Compared to other wired networks, complexity in the 3G UMTS is due its interactions with different entities. Within the UMTS, services have to deal with a great number of different QoS, small user display, variant bandwidth and small battery power. Most of the services are generally bind to the particular...

    Provided By University of Patras

  • White Papers // Apr 2010

    Designing and Developing Accessible Java Swing Applications

    Information and Communication Technology (ICT) applications and systems are not fully accessible today. This is because accessibility does not happen on its own. Many developers and designers are not fully equipped with evidence and knowledge related to the accessibility of their products or services. Existing development tools and pack-aged solutions...

    Provided By University of Patras

  • White Papers // Apr 2010

    Optimal Detector for Discrete Transmit Signals in Gaussian Interference Channels

    This paper addresses the design of optimal and near-optimal detectors for a practical interference channel scenario where the transmitters employ discrete modulation schemes. The conventional detectors, which either ignore the interference or successively detect then cancel the interference, typically assume that the desired signal and/or the interference are Gaussian. This...

    Provided By University of Patras

  • White Papers // Apr 2010

    Optimal Training Design and Placement for Channel Estimation in Cooperative Networks

    In this paper, optimal training design and placement are studied for channel estimation in a frequency selective, single relay, amplify and forward cooperative system. Using a two-phase transmission protocol, the power distribution between the phases, among the pilot tones as well as the positioning of pilot tones within the transmitted...

    Provided By University of Patras

  • White Papers // Feb 2010

    The Impact of FEC on Mobile Multicast Power Control

    3GPP has standardized the use of forward error correction for the provision of reliable data transmission in the mobile multicast framework. In this paper, the authors present a study of the impact of application layer forward error correction on power control during mobile multicast transmission. The evaluation is performed with...

    Provided By University of Patras

  • White Papers // Feb 2010

    Adopting Forward Error Correction for Multicasting Over Cellular Networks

    FEC is an error control method that can be used to augment or replace other methods for reliable data transmission. Such schemes inevitably add a constant overhead in the transmitted data. However, they are so simple as to meet a prime objective for UMTS multicast services, that is scalability to...

    Provided By University of Patras

  • White Papers // Jan 2010

    A Peer-to-Peer Framework for Globally-Available Sensor Networks and Its Application in Building Management

    In this paper, the authors present the architecture and implementation of WebDust, a software platform for managing multiple, heterogeneous (both in terms of software and hardware), geographically disparate sensor networks. They describe in detail the main concepts behind its design, and basic aspects of its implementation, including the services provided...

    Provided By University of Patras

  • White Papers // Jul 2009

    Optimal Detector for Channels With Non-Gaussian Interference

    The detection problem in the Gaussian interference channel is addressed, when transmitters employ non-Gaussian schemes designed for the single-user Gaussian channel. A structure consisting of a separate symbol-by-symbol detector and a hard decoder is considered. Given this structure, an optimal detector is presented that is compared to an interference-unaware conventional...

    Provided By University of Patras

  • White Papers // Jul 2009

    Security Services in the Greek School Network

    The Greek School Network (GSN) is a closed educational network that offers advanced telematic and networking services to all primary/secondary education schools and educational administration offices in Greece. The primary objective of GSN is to provide a network infrastructure for the interconnection of school PC laboratories so that modern educational...

    Provided By University of Patras

  • White Papers // Jun 2009

    Efficient Pipelined Hardware Implementation of RIPEMD-160 Hash Function

    In this paper an efficient implementation of Ripemd- 160 hash function is presented. Hash functions are a special family of cryptographic algorithms, which is used in technological applications with requirements for security, confidentiality and validity. Applications like PKI, IPSec, DSA, MAC's incorporate hash functions and are used widely today. The...

    Provided By University of Patras

  • White Papers // Jun 2009

    Integrating e-Learning Environments With Computational Intelligence Assessment Agents

    In this contribution an innovative platform is being presented that integrates intelligent agents in legacy e-learning environments. It introduces the design and development of a scalable and interoperable integration platform supporting various assessment agents for e-learning environments. The agents are implemented in order to provide intelligent assessment services to computational...

    Provided By University of Patras

  • White Papers // Jun 2009

    Architecture and DSP Implementation of a DVB-S2 Baseband Demodulator

    This paper presents the design and implementation of a baseband demodulator for DVB-S2 satellite receivers. In order to meet the requirements of different complex and multi-domain signal processing stages of the DVB-S2 baseband signal-flow, the presented architecture is based on efficient fixed-point implementation of the various demodulation algorithms and on...

    Provided By University of Patras

  • White Papers // May 2009

    A Framework Supporting Extreme Emergency Services

    In many extreme emergency scenarios, such as natural or manmade disasters, the rescuers may face difficulty using traditional legacy networks due to destruction or collapse of infrastructure in such events or in case of remote disaster locations. The nature of Mobile Ad hoc NETworks (MANETs) makes them suitable to be...

    Provided By University of Patras

  • White Papers // May 2009

    Multimedia Transmission Over Optic, DSL and PLC Systems

    This work presents an analysis based on an multimedia transmission generated on optical fiber backbone and two combined access technologies, PLC (Power Line Communications) and ADSL2+ (Asymmetric Digital Subscriber Line), called of pDSL. This paper points a case study of multimedia traffic using pDSL combination with intention to present measured...

    Provided By University of Patras

  • White Papers // Apr 2009

    Coding Efficiency and Reliability in Probe-Based Storage Devices

    High density probe-based storage devices use multiple, simultaneously accessed parallel channels for achieving high I/O data rates. This paper presents an analytical methodology for evaluating the performance of coding and interleaving schemes in such devices, when they are affected by burst errors. Markov processes are used to describe the burstiness...

    Provided By University of Patras

  • White Papers // Mar 2009

    Measurements-Based Modeling of Burst Errors on Multiple Parallel Storage Channels

    This paper presents a measurement-based burst error model for storage devices that use multiple parallel channels when they are affected by external disturbances. The burst errors are modeled using a set of Markov processes and channel error measurements are exploited to specify the parameters of the Markov processes and to...

    Provided By University of Patras

  • White Papers // Mar 2009

    A Software-Based Instrument for Testing and Monitoring Multi-Processing Communications Devices

    This paper presents a software-based instrument for testing and monitoring the behavior of complex communications systems that employ a number of interconnected DSPs. The instrument is based on a dynamic architecture that incorporates a set of distributed software probes for signal capturing and a central data acquisition unit for acquiring...

    Provided By University of Patras

  • White Papers // Feb 2009

    EXtensible Animator for Mobile Simulations: EXAMS

    One of the most widely used simulation environments for mobile wireless networks is the Network Simulator 2 (NS-2). However NS-2 stores its outcome in a text file, so there is a need for a visualization tool to animate the simulation of the wireless network. The purpose of this tool is...

    Provided By University of Patras

  • White Papers // Feb 2009

    Optimizing MBMS Power Allocation Through HSDPA Transmissions

    Multimedia Broadcast Multicast Service (MBMS) epitomizes the increasing popularity of enhanced end-user experience in Universal Mobile Telecommunications System (UMTS), since it allows the economical delivery of multimedia services to a large number of users. MBMS multicast supports both Point-To-Point (PTP) and Point-To-Multipoint (PTM) modes in order to confront the strict...

    Provided By University of Patras

  • White Papers // Feb 2009

    A Heuristic Method for Error Correction in Parallel Probe-Based Storage Devices

    This paper presents a new decoding algorithm that improves the reliability of probe-based storage devices, that use multiple, simultaneously accessed parallel fields, when they are affected by burst errors. The presented algorithm exploits the parallelism of the multiple storage fields and the used data allocation method and flags symbols as...

    Provided By University of Patras

  • White Papers // Feb 2009

    EXtensible Animator for Mobile Simulations: EXAMS

    One of the most widely used simulation environments for mobile wireless networks is the Network Simulator 2 (NS-2). However NS-2 stores its outcome in a text file, so there is a need for a visualization tool to animate the simulation of the wireless network. The purpose of this tool is...

    Provided By University of Patras

  • White Papers // Jun 2009

    Integrating e-Learning Environments With Computational Intelligence Assessment Agents

    In this contribution an innovative platform is being presented that integrates intelligent agents in legacy e-learning environments. It introduces the design and development of a scalable and interoperable integration platform supporting various assessment agents for e-learning environments. The agents are implemented in order to provide intelligent assessment services to computational...

    Provided By University of Patras

  • White Papers // Dec 2010

    Computational Intelligence Techniques and Agents' Technology in E-Learning Environments

    In this contribution a newly developed e-learning environment is presented, which incorporates Intelligent Agents and Computational Intelligence Techniques. The new e-learning environment is constituted by three parts, the E-learning platform Front-End, the Student Questioner Reasoning and the Student Model Agent. These parts are distributed geographically in dispersed computer servers, with...

    Provided By University of Patras

  • White Papers // Aug 2010

    A Quantitative Research On Physicians-Detailers Long-Term Relationships Building, In Prescribed Drug Marketing Contexts

    The presented research is part of a doctoral study, which, among others, investigated a wide array of relationship building constituents and effects that may evolve in the context of a physicians - detailers-pharmaceutical companies' network. Specifically, for the purposes of this paper, the authors select the variables detailer's listening efficacy,...

    Provided By University of Patras

  • White Papers // Jan 2011

    Longitudinal Analytics on Web Archive Data: It's About Time!

    Organizations like the Internet Archive have been capturing Web contents over decades, building up huge repositories of time-versioned pages. The timestamp annotations and the sheer volume of multi-modal content constitutes a gold mine for analysts of all sorts, across different application areas, from political analysts and marketing agencies to academic...

    Provided By University of Patras

  • White Papers // Jun 2009

    Efficient Pipelined Hardware Implementation of RIPEMD-160 Hash Function

    In this paper an efficient implementation of Ripemd- 160 hash function is presented. Hash functions are a special family of cryptographic algorithms, which is used in technological applications with requirements for security, confidentiality and validity. Applications like PKI, IPSec, DSA, MAC's incorporate hash functions and are used widely today. The...

    Provided By University of Patras

  • White Papers // May 2010

    The Effect Of Tax Incentives On Investment - Decisions Of Transnational Enterprises (TNEs) In An Integrated World: A Literature Review

    The aim of this paper is to provide a selective survey of both theoretical and empirical literature, concerning the factors, especially tax - incentives, that affect Foreign Direct Investment (FDI) inflows. Nowadays, TransNational Enterprises (TNEs) are major actors in international trade. For this reason, central-governments in OECD countries compete with...

    Provided By University of Patras

  • White Papers // Jan 2010

    A Peer-to-Peer Framework for Globally-Available Sensor Networks and Its Application in Building Management

    In this paper, the authors present the architecture and implementation of WebDust, a software platform for managing multiple, heterogeneous (both in terms of software and hardware), geographically disparate sensor networks. They describe in detail the main concepts behind its design, and basic aspects of its implementation, including the services provided...

    Provided By University of Patras

  • White Papers // Feb 2011

    Interference Mitigation Via Joint Detection in a Fading Environment

    This paper considers the detection problem for fading channels in the presence of interference when both the transmitter of interest and the interferers employ practical modulation schemes. It is shown that, for Rayleigh fading, it is possible to obtain symbol error rates that have the same dependence on the received...

    Provided By University of Patras

  • White Papers // Apr 2010

    Optimal Detector for Discrete Transmit Signals in Gaussian Interference Channels

    This paper addresses the design of optimal and near-optimal detectors for a practical interference channel scenario where the transmitters employ discrete modulation schemes. The conventional detectors, which either ignore the interference or successively detect then cancel the interference, typically assume that the desired signal and/or the interference are Gaussian. This...

    Provided By University of Patras

  • White Papers // Apr 2010

    Optimal Training Design and Placement for Channel Estimation in Cooperative Networks

    In this paper, optimal training design and placement are studied for channel estimation in a frequency selective, single relay, amplify and forward cooperative system. Using a two-phase transmission protocol, the power distribution between the phases, among the pilot tones as well as the positioning of pilot tones within the transmitted...

    Provided By University of Patras

  • White Papers // Apr 2010

    Enhancing Service Portability in Upcoming 3G UMTS Networks & Security Aspects

    Compared to other wired networks, complexity in the 3G UMTS is due its interactions with different entities. Within the UMTS, services have to deal with a great number of different QoS, small user display, variant bandwidth and small battery power. Most of the services are generally bind to the particular...

    Provided By University of Patras

  • White Papers // Nov 2011

    A Low-Complexity Resource Allocation Algorithm for MIMO-OFDMA Multicast Systems With Spectrum-Guarantee Provisioning

    This paper studies the important problem of resource allocation for the down-link of Multiple-Input Multiple-Output (MIMO) Multicast Wireless Systems operating over frequency-selective channels. Multi-casting over wireless OFDMA networks is expected to enhance significantly the multimedia access and provide ubiquitous multimedia experience to large number of users, since a sub-carrier is...

    Provided By University of Patras

  • White Papers // Nov 2010

    Experimental Demonstration of an Impairment Aware Network Planning and Operation Tool for Transparent/Translucent Optical Networks

    Core optical networks using reconfigurable optical switches and tunable lasers appear to be on the road towards widespread deployment and could evolve to all-optical mesh networks in the coming future. Considering the impact of physical layer impairments in the planning and operation of all-optical (and translucent) networks is the main...

    Provided By University of Patras

  • White Papers // Oct 2010

    Using Flash Memories as Simo Channels for Extending the Lifetime of Solid-State Drives

    Reliability and I/O performance are the two basic metrics that determine the quality of Solid-State Drives (SSDs), especially in enterprise storage systems. Flash memories, the most popular non-volatile memory used in today's solid-state drives, demonstrate a time-varying behavior in terms of raw bit errors per program/erase cycle. This paper presents...

    Provided By University of Patras

  • White Papers // Apr 2009

    Coding Efficiency and Reliability in Probe-Based Storage Devices

    High density probe-based storage devices use multiple, simultaneously accessed parallel channels for achieving high I/O data rates. This paper presents an analytical methodology for evaluating the performance of coding and interleaving schemes in such devices, when they are affected by burst errors. Markov processes are used to describe the burstiness...

    Provided By University of Patras

  • White Papers // Jun 2009

    Architecture and DSP Implementation of a DVB-S2 Baseband Demodulator

    This paper presents the design and implementation of a baseband demodulator for DVB-S2 satellite receivers. In order to meet the requirements of different complex and multi-domain signal processing stages of the DVB-S2 baseband signal-flow, the presented architecture is based on efficient fixed-point implementation of the various demodulation algorithms and on...

    Provided By University of Patras

  • White Papers // Mar 2009

    Measurements-Based Modeling of Burst Errors on Multiple Parallel Storage Channels

    This paper presents a measurement-based burst error model for storage devices that use multiple parallel channels when they are affected by external disturbances. The burst errors are modeled using a set of Markov processes and channel error measurements are exploited to specify the parameters of the Markov processes and to...

    Provided By University of Patras

  • White Papers // Mar 2009

    A Software-Based Instrument for Testing and Monitoring Multi-Processing Communications Devices

    This paper presents a software-based instrument for testing and monitoring the behavior of complex communications systems that employ a number of interconnected DSPs. The instrument is based on a dynamic architecture that incorporates a set of distributed software probes for signal capturing and a central data acquisition unit for acquiring...

    Provided By University of Patras

  • White Papers // Feb 2009

    A Heuristic Method for Error Correction in Parallel Probe-Based Storage Devices

    This paper presents a new decoding algorithm that improves the reliability of probe-based storage devices, that use multiple, simultaneously accessed parallel fields, when they are affected by burst errors. The presented algorithm exploits the parallelism of the multiple storage fields and the used data allocation method and flags symbols as...

    Provided By University of Patras

  • White Papers // Jul 2008

    A Software-Radio Test-Bed for Measuring the Performance of DVB-S2 Receiver Circuits

    This paper presents a flexible and versatile DVBS2 test-bed that combines a set of automated signal generation and analysis instruments along with a powerful software radio processing unit for executing performance analysis experiments of DVB-S2 receiver circuits using realistic scenarios. The testbed provides a rich set of forward satellite channel...

    Provided By University of Patras

  • White Papers // May 2008

    Diversity and MIMO Performance Evaluation of Common Phase Center Multi Element Antenna Systems

    The diversity and Multiple Input Multiple Output (MIMO) performance provided by Common Phase Center Multi Element Antenna (CPCMEA) systems is evaluated using two practical methods which make use of the realized active element antenna patterns. These patterns include both the impact of the mutual coupling and the mismatch power loss...

    Provided By University of Patras

  • White Papers // Jun 2010

    Coverage-Adaptive Random Walks for Fast Sensory Data Collection

    Random walks in wireless sensor networks can serve as fully local, very simple strategies for sink motion that significantly reduce energy dissipation a lot but increase the latency of data collection. To achieve satisfactory energy-latency trade-offs the sink walks can be made adaptive, depending on network parameters such as density...

    Provided By University of Patras

  • White Papers // Mar 2011

    Enabling Live Video Streaming Services Realization in Telecommunication Networks Using P2P Technology

    Peer-To-Peer (P2P) systems enjoy wide adoption from internet users. Success of P2P architecture is due to its ability to scale and to organize dynamically the traffic according to the user resources and requests. On the contrary, P2P adoption is constrained in non-real time applications, like content distribution and file sharing....

    Provided By University of Patras

  • White Papers // May 2009

    A Framework Supporting Extreme Emergency Services

    In many extreme emergency scenarios, such as natural or manmade disasters, the rescuers may face difficulty using traditional legacy networks due to destruction or collapse of infrastructure in such events or in case of remote disaster locations. The nature of Mobile Ad hoc NETworks (MANETs) makes them suitable to be...

    Provided By University of Patras

  • White Papers // Mar 2012

    Multilateration: Methods for Clustering Intersection Points for Wireless Sensor Networks Localization With Distance Estimation Error

    In this paper, the authors describe three methods for localizing a wireless sensor network node, using anchor nodes in its neighbourhood, when there is an error in distance estimation present. They use the intersection points of the circles formed with the estimated distances from each anchors and they apply different...

    Provided By University of Patras

  • White Papers // Feb 2010

    Adopting Forward Error Correction for Multicasting Over Cellular Networks

    FEC is an error control method that can be used to augment or replace other methods for reliable data transmission. Such schemes inevitably add a constant overhead in the transmitted data. However, they are so simple as to meet a prime objective for UMTS multicast services, that is scalability to...

    Provided By University of Patras

  • White Papers // Jun 2012

    Enhancing Reliable Mobile Multicasting With RaptorQ FEC

    A crucial point on the successful deployment of multicast services is the enhanced reliability by means of advanced error control schemes. To this direction Third Generation Partnership Project (3GPP) has standardized exclusively for Multimedia Broadcast/Multicast Services (MBMS) the use of a Forward Error Correction (FEC) mechanism on the application layer...

    Provided By University of Patras

  • White Papers // Jul 2012

    A Performance Study of Fractional Frequency Reuse in OFDMA Networks

    Long Term Evolution (LTE) technology is considered as the most possible candidate for next generation mobile communications. LTE networks offer high capacity and are specified and designed to accommodate small, high performance, power-efficient end-user devices. One limiting factor that influences LTE performance is the interference from neighbor cells, the so...

    Provided By University of Patras

  • White Papers // Jul 2012

    Genetic Optimization for Spectral Efficient Multicasting in LTE Systems

    Past research has proposed the usage of assisting cells with Multimedia Broadcast/Multicast Service (MBMS) over a Single Frequency Network (MBSFN) to increase the Spectral Efficiency (SE) of LTE. In this paper, the authors propose and investigate a method for optimizing the power consumption of the network while retaining an acceptable...

    Provided By University of Patras

  • White Papers // Aug 2011

    AL-FEC for Streaming Services Over LTE Systems

    The Third Generation Partnership Project (3GPP), recently introduced the evolution of the Third Generation (3G) cellular networks, the Long Term Evolution (LTE) telecommunication system. A key aspect of LTE specifications is the enhancement of Multimedia Broadcast/Multicast Services (MBMS), where the same content is transmitted to multiple users located in a...

    Provided By University of Patras

  • White Papers // Mar 2011

    Combining MBSFN and PTM Transmission Schemes for Resource Efficiency in LTE Networks

    Long Term Evolution (LTE) systems allow the transmission of rich multimedia services by utilizing the Multimedia Broadcast/Multicast Service (MBMS) over a Single Frequency Network (MBSFN). During MBSFN transmission a time-synchronized common waveform is transmitted from multiple cells. The 3rd Generation Partnership Project (3GPP) has specified that Point-To-Multipoint (PTM) transmission can...

    Provided By University of Patras

  • White Papers // Jun 2011

    Reliable Multicasting Over LTE: A Performance Study

    With the booming of multimedia services, the 3rd Generation Partnership Project (3GPP) has introduced the evolved Multimedia Multicast/Broadcast Service (e-MBMS) feature for LTE systems. The main objective of MBMS is to introduce real broadcast distribution capabilities into cellular systems. This purposed 3GPP to introduce the MBMS over a Single Frequency...

    Provided By University of Patras

  • White Papers // Feb 2010

    The Impact of FEC on Mobile Multicast Power Control

    3GPP has standardized the use of forward error correction for the provision of reliable data transmission in the mobile multicast framework. In this paper, the authors present a study of the impact of application layer forward error correction on power control during mobile multicast transmission. The evaluation is performed with...

    Provided By University of Patras

  • White Papers // Dec 2008

    An Efficient Mechanism for Power Control Optimization in MBMS Enabled UTRAN

    This paper proposes a power control mechanism for the efficient radio bearer selection in the Multimedia Broadcast/Multicast Service (MBMS) framework of Universal Mobile Telecommunications System (UMTS). The selection of the most efficient transport channel in terms of power consumption is a key point for MBMS enabled UMTS networks, since a...

    Provided By University of Patras

  • White Papers // Feb 2009

    Optimizing MBMS Power Allocation Through HSDPA Transmissions

    Multimedia Broadcast Multicast Service (MBMS) epitomizes the increasing popularity of enhanced end-user experience in Universal Mobile Telecommunications System (UMTS), since it allows the economical delivery of multimedia services to a large number of users. MBMS multicast supports both Point-To-Point (PTP) and Point-To-Multipoint (PTM) modes in order to confront the strict...

    Provided By University of Patras

  • White Papers // Feb 2012

    Plastic-Based Substrate Integrated Waveguide (SIW) Components and Antennas

    This paper presents the implementation of Substrate Integrated Waveguide (SIW) components and antennas in a PolyEthylene Terephthalate (PET) substrate. PET is a cheap and flexible material, which represents an important candidate for the development of future conformal and wearable wireless systems. The characterization of the electrical properties of the material...

    Provided By University of Patras

  • White Papers // Jul 2008

    ISOLA a Fortran Code and a Matlab GUI to Perform Multiple-Point Source Inversion of Seismic Data

    In this paper a software package for multiple or single point source inversion is presented. The package consists of ISOLA-GUI, a user-friendly MATLAB-based interface, and the ISOLA Fortran code, which is the computational core of the application. The software advantage is the graphical interface that provides the user with an...

    Provided By University of Patras

  • White Papers // Sep 2008

    Recent Advances in Multimedia Information System Security

    A multimedia communication system enables multimedia data's generation, storage, management, distribution, receiving, consuming, editing, sharing, and so on. In such systems, there are various security issues, which must be considered such as eavesdropping, intrusion, forgery, piracy and privacy, etc. Until now, various security solutions for multimedia communication systems have been...

    Provided By University of Patras

  • White Papers // Jul 2009

    Security Services in the Greek School Network

    The Greek School Network (GSN) is a closed educational network that offers advanced telematic and networking services to all primary/secondary education schools and educational administration offices in Greece. The primary objective of GSN is to provide a network infrastructure for the interconnection of school PC laboratories so that modern educational...

    Provided By University of Patras