Endre søk
Begrens søket
12 51 - 68 of 68
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Treff pr side
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 51.
    Sravani, Kancharla
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Study on Energy saving in Wireless Mesh Networks Using Network Simulator - 32016Independent thesis Advanced level (degree of Master (One Year)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Context: Wireless Mesh Network (WMN) is a form of ad-hoc network with flexible backhaul infrastructure and configuration, provides adaptive wireless internet connectivity to end users with high reliability. WMN is a wireless network consisting of mesh clients, mesh routers and gateways which are organized in a mesh topology with decentralized nature can consume more energy for data transmission. The networking performance of WMNs can be degraded due to the fact of high energy consumption for data transmission. Therefore, energy efficiency is the primary factor for attaining eminent performance. Organizing efficient routing and proper resource allocation can save huge amount of energy.

    Objectives: The main goal of this thesis is to reduce the energy consumption in WMNs. To do this, a new energy efficient routing algorithm is suggested. Adaptive rates based on rate allocation strategy and end to end delay metric are used mainly for optimal path selection in routing, which may in turn reduces the resource utilization and energy consumption.

    Method: An energy efficient routing algorithm is implemented by using the Ad hoc OnDemand Distance Vector (AODV) routing protocol. The RREQ packet in AODV is modified by adding a new field known as delay parameter which measures end to end delay between nodes. Adaptive rates obtained from Rate allocation policy are considered in the routing process to reduce energy consumption in the network. Energy measurement of the WMN and its performance is evaluated by measuring the metrics such as Throughput, End-to-End delay, Packet Delivery Ratio (PDR). For performing the simulation process, in this thesis, Network Simulator - 3 (NS-3) which is an open source discrete-event network simulator in which simulation models can be executed in C++ and Python is used. Using NetAnim-3.107 animator in NS-3-25.1, traffic flows between all the nodes are displayed.

    Results: The results are taken for existing algorithm and proposed algorithm for 25,50,75 and 100 nodes. Comparison of results shows that the total energy consumption is reduced for proposed algorithm for in all four scenarios. Conclusion: Energy efficient routing algorithm is implemented in different scenarios of radio access networks and energy is saved. Due to this algorithm even the performance metrics, Throughput, End-to-End delay, Packet Delivery Ratio (PDR) have shown eminent performance.

  • 52.
    Sriram Prashanth, Naguru
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    OpenFlow Switching Performance using Network Simulator - 32016Independent thesis Advanced level (degree of Master (One Year)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Context. In the present network inventive world, there is a quick expansion of switches and protocols, which are used to cope up with the increase in customer requirement in the networking. With increasing demand for higher bandwidths and lower latency and to meet these requirements new network paths are introduced. To reduce network load in present switching network, development of new innovative switching is required. These required results can be achieved by Software Define Network or Traditional layer-3 technologies.Objectives. In this thesis, the end to end (e2e) transmission performance of OpenFlow and Layer-3 switches and their dynamic characteristics are investigated using network simulation.Methods. To replicate real life network topology and evaluate e2e transmission performance, a simulation based test-bed is implemented for both OpenFlow switch and layer-3 switch. The test beds are implemented using Network Simulator-3 (NS3). A two-tire network topology is designed with specified components for performance evaluation.Results. The performance metrics like throughput, average delay, simulation time and Packet Delivery Ratio (PDR) are measured, results are analyzed statistically and are compared. The behavior of network traffic in both the topologies are understood using NS-3 and explained further in the thesis.Conclusions. The analytical and statistical results from simulation show that OpenFlow switching performs relatively better than layer-3 switching.

  • 53.
    Stezenbach, David
    et al.
    University of Vienna, AUT.
    Tutschku, Kurt Tutschku
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datalogi och datorsystemteknik.
    A Performance Evaluation Metric for NFV Elements on Multiple Timescales2013Inngår i: Proceeding of the Global Communications Conference 2013 (GLOBECOM 2013)., 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Todays virtualization technologies are manifold and a comparison is hardly achievable. Thus, a metric independent from the virtualization technology is required to compare different systems. The metric is measurable in a passive way, hence, no artificial traffic has to be generated, and the virtualization system needs not to be modified. It evaluates the throughput of events on different time slices. This methodology, in contrast to existing jitter evaluations, enables the identification of critical timescales in the virtualization system. In this demonstration a proof-of-concept for a performance metric for NFV elements on multiple timescales is presented. In a reduced environment consisting of a single virtual router host the influences of hardware resource sharing and other impact factors (e.g. cpu, memory or disc load) are made visible. The demonstration gives an example of a performance degrease on smaller timescales, which can not be identified by a common throughput measurement over time. Thus, the presented metric enables to identify critical system conditions and can be used to optimize the scheduling of NFV, to compare different virtualization technologies, or to grade the performance for specific applications.

  • 54.
    Sun, Bin
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kreativa teknologier.
    Cheng, Wei
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kreativa teknologier.
    Bai, Guohua
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kreativa teknologier.
    Goswami, Prashant
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kreativa teknologier.
    Correcting and complementing freeway traffic accident data using mahalanobis distance based outlier detection2017Inngår i: Technical Gazette, ISSN 1330-3651, E-ISSN 1848-6339, Vol. 24, nr 5, s. 1597-1607Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A huge amount of traffic data is archived which can be used in data mining especially supervised learning. However, it is not being fully used due to lack of accurate accident information (labels). In this study, we improve a Mahalanobis distance based algorithm to be able to handle differential data to estimate flow fluctuations and detect accidents and use it to support correcting and complementing accident information. The outlier detection algorithm provides accurate suggestions for accident occurring time, duration and direction. We also develop a system with interactive user interface to realize this procedure. There are three contributions for data handling. Firstly, we propose to use multi-metric traffic data instead of single metric for traffic outlier detection. Secondly, we present a practical method to organise traffic data and to evaluate the organisation for Mahalanobis distance. Thirdly, we describe a general method to modify Mahalanobis distance algorithms to be updatable. © 2017, Strojarski Facultet. All rights reserved.

  • 55.
    Tran, Dang Ninh
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kreativa teknologier.
    Zepernick, Hans-Juergen
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kreativa teknologier.
    Chu, Thi My Chinh
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kreativa teknologier.
    On Moderately Significant Bit Data Hiding Techniques for High-Definition Images2018Inngår i: International Conference on Advanced Technologies for Communications, IEEE Computer Society , 2018, s. 47-52Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, we study moderately significant bit data hiding techniques for high-definition (HD) images. In contrast to least significant bit data hiding, we explore the potential of HD images to engage higher order bits for increasing the capacity of hiding secret images. In particular, the number of secret images embedded in moderately significant bits of a given cover image is successively increased to study the impact of this data hiding approach on image fidelity and image quality in the context of HD images. A comprehensive performance assessment is conducted on the stego-image carrying the secret images in terms of peak-signal-to-noise ratio (PSNR) and structural similarity (SSIM) index. It is shown that HD images indeed offer the potential of hiding several images within certain image fidelity and objective perceptual image quality constraints of the resulting stego-HD images. © 2018 IEEE.

  • 56.
    Tran, Hung
    et al.
    Malardalen Univ, S-72123 Vasteras, Sweden..
    Zepernick, Hans-Juergen
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem. Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för telekommunikationssystem. Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för signalbehandling. Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation. Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för elektroteknik.
    Phan, Hoc
    Univ Reading, Reading RG6 6AY, Berks, England..
    On Throughput and Quality of Experience in Cognitive Radio Networks2016Inngår i: 2016 IEEE WIRELESS COMMUNICATIONS AND NETWORKING CONFERENCE, IEEE , 2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, a performance analysis for cognitive radio networks (CRNs) under the outage probability constraint of the primary user and peak transmit power constraint of the secondary user is conducted. Given an automatic repeat request protocol, analytical expressions for the packet delay and throughput of the CRN are derived. Most importantly, these expressions can be used to understand the quality of experience on web services which are assumed to be offered by the considered CRN.

  • 57.
    Tran, Hung
    et al.
    Malardalen Univ, SWE.
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Proactive Attack: A Strategy for Legitimate Eavesdropping2016Inngår i: 2016 IEEE Sixth International Conference on Communications and Electronics (ICCE), IEEE, 2016, s. 457-461Konferansepaper (Fagfellevurdert)
  • 58.
    Tran, Hung
    et al.
    Mälardalen University, SWE.
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Sibomana, Louis
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Performance of cognitive radio networks under interference constraints of multiple primary users2016Inngår i: 2016, 10th International Conference on Signal Processing and Communication Systems, ICSPCS 2016 - Proceedings, IEEE, 2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, we study the performance of point-to-point communication in spectrum sharing systems under the peak interference power constraint of multiple primary users. In particular, we assume that the channels undergo independent but not necessarily identically distributed Nakagami-m fading with integer values of fading severity parameter m. The cumulative distribution function and probability density function for the signal-to-noise ratio are derived. Based on these formulas, we obtain analytical expressions for the outage probability, the ergodic capacity, and the symbol error probability. Numerical results are also provided to investigate the impact of the peak interference power-to-noise ratio, the number of primary users, and fading parameters on the performance of the secondary network. © 2016 IEEE.

  • 59.
    Tutschku, Kurt
    Institute of Computer ScienceUniversity of Würzburg, DEU.
    A Measurement-based Traffic Profile of the eDonkey Filesharing Service2004Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Peer-to-peer file sharing applications have evolved to one of the major traffic sources in the Internet. In particular, the eDonkey file sharing system and its derivatives are causing high amounts of traffic volume in today’s networks. The eDonkey system is typically used for exchanging very large files like audio/video CDs or even DVD images. In this report we provide a measurement based traffic profile of the eDonkey service. Furthermore, we discuss how this type of service increases the ”mice and elephants” phenomenon in the Internet traffic characteristics.

  • 60.
    Tutschku, Kurt
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Ahmadi Mehri, Vida
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Carlsson, Anders
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Chivukula, Krishna Varaynya
    CityNetwork Webbhotell AB.
    Johan, Christenson
    CityNetwork Webbhotell AB.
    On Resource Description Capabilities of On-Board Tools for Resource Management in Cloud Networking and NFV Infrastructures2016Inngår i: 2016 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS WORKSHOPS (ICC), 2016, s. 442-447Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The rapid adoption of networks that are based on "cloudification" and Network Function Virtualisation (NFV) comes from the anticipated high cost savings of up to 70% in their build and operation. The high savings are founded in the use of general standard servers, instead of single-purpose hardware, and by efficiency resource sharing through virtualisation concepts. In this paper, we discuss the capabilities of resource description of "on-board" tools, i.e. using standard Linux commands, to enable OPEX savings. We put a focus on monitoring resources on small time-scales and on the variation observed on such scales. We introduce a QoE-based comparative concept that relates guest and host views on "utilisation" and "load" for the analysis of the variations. We describe the order of variations in "utilisation" and "load" by measurement and by graphical analysis of the measurements. We do these evaluations for different host operating systems and monitoring tools.

  • 61.
    Tutschku, Kurt Tutschku
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Ahmadi Mehri, Vida
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Carlsson, Anders
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Towards Multi-layer Resource Management in Cloud Networking and NFV Infrastructures2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Cloud Networking (CN) and related conceptsoffer appealing novelties to Cloud Computing (CC) customers.They can do a one-stop-shopping for network-enhanced cloudservices. In addition, the costs of such services might below due to multiple customers sharing the infrastructures.Moreover, telecommunication network operators are adopt-ing the CN in theirNetwork Functions Virtualisation (NFV)framework for reducing costs and increasing the flexibility oftheir networks. The technical appeal of CN comes from thetight integration of CC and smart networks. The economicalattractiveness results from avoiding dedicated hardware, shar-ing of resources, and simplified resource management (RM) asseen by the users respectively by the applications. The visionof cheap and integrated CN services is obviously attractive,but it is also evident that it will require more complex RMprocedures for efficiently balancing the usage of all resources.In this contribution, we suggest an initial architecture forintegrated and practical RM in CN and NFV systems. TheRM concept aims at locating and analysing performancebottlenecks, efficiency problems, and eventually discover un-used resources. The suggested architecture is based on alayered view on the system. Moreover, we detail difficultiesin practical resources usage monitoring which, in turn, definerequirements for a RM architecture. The requirement analysisis based on measurements in a CN infrastructure.

  • 62.
    Tutschku, Kurt Tutschku
    et al.
    Universität Wien, AUT.
    Zinner, Thomas
    University of Wuerzburg.
    Nakao, Akihiro
    University of Tokyo.
    Tran-Gia, Phuoc
    University of Wuerzburg.
    Network Virtualization: Implementation Steps Towards the Future Internet.2009Inngår i: Workshop on Overlay and Network Virtualization at KIVS 2009, 2009Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper we will investigate why and how Network Virtualization (NV) can overcome the shortfalls of the current system and how it paves the way for the Future Internet. Therefore, we will first discuss some major deficiencies and achievements of today’s Internet. Afterwards, we identify three major building blocks of NV: a) the use of application-specific routing overlays, b) the safe consolidation of resources by OS virtualization on a generic infrastructure, and c) the exploitation of the network diversity for performance enhancements and for new business models, such as the provisioning of intermediate nodes or path oracles. Subsequently, we discuss an implementation scheme for network virtualization or routing overlays based on one-hop source routers (OSRs). The capabilities of the combination of NV and OSRs are demonstrated by a concurrent multipath transmission (CMP) mechanism (also known as stripping) for obtaining high throughput transmission pipes. The suggested stripping mechanism constitutes a first instance of a refinement of the concept of NV, the idea of transport system virtualization.

  • 63.
    van der Mei, Rob
    et al.
    Centrum Wiskunde and Informatica (CWI), NLD.
    van den Berg, Hans
    TNO, NLD.
    Ganchev, Ivan
    University of Limerick, IRE.
    Tutschku, Kurt Tutschku
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datalogi och datorsystemteknik.
    Leitner, Philipp
    University of Zurich, CHE.
    Lassila, Pasi
    Aalto University, FIN.
    Burakowski, Wojciech
    Warsaw University of Technology, POL.
    Liberal, Fidel
    University of the Basque Country (UPV/EHU), ESP.
    Arvidsson, Åke
    Kristianstad University, SWE.
    Hoßfeld, Tobias
    lInstitute of Computer Science and Business Information Systems (ICB), DEU.
    Wac, Katarzyna
    University of Geneva, CHE.
    Melvin, Hugh
    National University of Ireland, IRE.
    Galinac Grbac, Tihana
    University of Rijeka, HRV.
    Haddad, Yoram
    JCT-Lev Academic Center, ISR.
    Key, Peter
    Microsoft Research Ltd., GBR.
    State of the Art and Research Challenges in the Area of Autonomous Control for a Reliable Internet of Services2018Inngår i: Autonomous Control for a Reliable Internet of Services: Methods, Models, Approaches, Techniques, Algorithms, and Tools / [ed] Ganchev, Ivan, van der Mei, Robert D., van den Berg, J.L., Springer Publishing Company, 2018Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    The explosive growth of the Internet has fundamentally changed the global society. The emergence of concepts like service-oriented architecture (SOA), Software as a Service (SaaS), Platform as a Service (PaaS), Infrastructure as a Service (IaaS), Network as a Service (NaaS) and Cloud Computing in general has catalyzed the migration from the information-oriented Internet into an Internet of Services (IoS). This has opened up virtually unbounded possibilities for the creation of new and innovative services that facilitate business processes and improve the quality of life. However, this also calls for new approaches to ensuring quality and reliability of these services. The goal of this book chapter is to first analyze the state-of-the-art in the area of autonomous control for a reliable IoS and then to identify the main research challenges within it. A general background and high-level description of the current state of knowledge is presented. Then, for each of the three subareas, namely the autonomous management and real-time control, methods and tools for monitoring and service prediction, and smart pricing and competition in multi-domain systems, a brief general introduction and background are presented, and a list of key research challenges is formulated.

  • 64.
    venkesh, kandari
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Implementation and Performance Optimization of WebRTC Based Remote Collaboration System2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
  • 65.
    Vesterlund, Martin
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datalogi och datorsystemteknik.
    Wiklund, Viktor
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datalogi och datorsystemteknik.
    Is this your smart phone?: On connecting MAC-addresses to a specific individual using access point data2015Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Context. The potential to track individuals become greater and greater in the society today. We want to develop a method that is easy to understand so more people can participate in the discussion about the collection, and storing, of seemingly non-invasive device data and personal integrity.

    Objectives. In this work we investigate the potential to connect a WiFi enabled device to a known individual by analysing log files. Since we want to keep the method as simple as possible we choose to not use machine learning because this might add unnecessary layers of complexity.

    Methods. The conducted experiments were performed against a test group consisting of six persons. The dataset used consisted of authentication logs from a university WiFi-network collected during a month and data acquired by capturing WiFi-traffic.

    Results. We were able to connect 67% of the targeted test persons to their smart phones and 60% to their laptops.

    Conclusions. In this work we conclude that a device identifier in combination with data that can tie it to a location at a given time is to be seen as sensitive information with regard to personal integrity. We also conclude that it is possible to create and use an easy method to connect a device to a given person.

  • 66.
    Wen, Wei
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Khatibi, Siamak
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    A Software Method to Extend Tonal Levels and Widen Tonal Range of CCD Sensor Images2015Inngår i: 2015 9TH INTERNATIONAL CONFERENCE ON SIGNAL PROCESSING AND COMMUNICATION SYSTEMS (ICSPCS), IEEE Communications Society, 2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    As one of important outcomes of the past decades of researches on sensor arrays for digital cameras, the manufacturers of sensor array technology have responded to the necessity and importance of obtaining an optimal fill factor, which has great impact on collection of incident photons on the sensor, with hardware solution e.g. by introducing microlenses. However it is still impossible to make a fill factor of 100% due to the physical limitations in practical development and manufacturing of digital camera. This has been a bottle neck problem for improving dynamic range and tonal levels for digital cameras e.g. CCD cameras. In this paper we propose a software method to not only widen the recordable dynamic range of a captured image by a CCD camera but also extend its tonal levels. In the method we estimate the fill factor and by a resampling process a virtual fill factor of 100% is achieved where a CCD image is rearranged to a new grid of virtual subpixels. A statistical framework including local learning model and Bayesian inference is used for estimating new sub-pixel intensity values. The highest probability of sub-pixels intensity values in each resampled pixel area is used to estimate the pixel intensity values of the new image. The results show that in comparison to the methods of histogram equalization and image contrast enhancement, which are generally used for improving the displayable dynamic range on only one image, the tonal levels and dynamic range of the image is extended and widen significantly and respectively.

  • 67. Yeoh, Phee Lep
    et al.
    Elkashlan, Maged
    Duong, Trung Q.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Yang, Nan
    da Costa, Daniel Benevides
    Transmit Antenna Selection for Interference Management in Cognitive Relay Networks2014Inngår i: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 63, nr 7, s. 3250-3262Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We propose transmit antenna selection (TAS) in decode-and-forward (DF) relaying as an effective approach to reduce the interference in underlay spectrum sharing networks with multiple primary users (PUs) and multiple antennas at the secondary users (SUs). We compare two distinct protocols: 1) TAS with receiver maximal-ratio combining (TAS/MRC) and 2) TAS with receiver selection combining (TAS/SC). For each protocol, we derive new closed-form expressions for the exact and asymptotic outage probability with independent Nakagami-m fading in the primary and secondary networks. Our results are valid for two scenarios related to the maximum SU transmit power, i.e., P, and the peak PU interference temperature, i.e., Q. When P is proportional to Q, our results confirm that TAS/MRC and TAS/SC relaying achieve the same full diversity gain. As such, the signal-to-noise ratio (SNR) advantage of TAS/MRC relaying relative to TAS/SC relaying is characterized as a simple ratio of their respective SNR gains. When P is independent of Q, we find that an outage floor is obtained in the large P regime where the SU transmit power is constrained by a fixed value of Q. This outage floor is accurately characterized by our exact and asymptotic results.

  • 68.
    Zepernick, Hans-Jürgen
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Iqbal, Muhammad Imran
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Khatibi, Siamak
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Quality of Experience of Digital Multimedia Broadcasting Services: An Experimental Study2016Inngår i: 2016 IEEE Sixth International Conference on Communications and Electronics (ICCE), IEEE, 2016, s. 437-442Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Digital multimedia broadcasting (DMB), also know as mobile TV, has been developed as a digital radio transmission technology that supports multimedia services such as TV, radio and datacasting. Especially, the terrestrial version of DMB, referred to as T-DMB, has been widely deployed in South Korea to deliver multimedia services to mobile devices ranging from smartphones to laptops, car navigation systems, and telematic devices for automotives. Although T-DMB is claimed to theoretically work without difficulties in vehicles with speeds up to 300 km/h, in practice, occasional skips and other temporal and spatial artifacts have been observed. In this paper, we provide an experimental study of the Quality of Experience (QoE) of T-DMB with focus on TV services. The study is based on a measurement campaign that was conducted in a live T-DMB system in South Korea consisting of TV broadcasters and DMB receivers in vehicles. In particular, a comprehensive subjective test has been conducted on the DMB test material that was obtained in the measurement campaign. A statistical analysis of the user ratings obtained from the subjective tests is reported to quantify the QoE of T-DMB in terms of mean opinion scores (MOSs) and higher order statistics. The obtained results may be used to develop related QoE models for this type of systems and services. In particular, the results may suggest to exploit insights obtained from higher order statistics such as skewness and kurtosis into QoE modeling rather than considering only MOS and variance.

12 51 - 68 of 68
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf