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  • 1351. Yang, Zhe
    et al.
    Mohammed, Abbas
    Hult, Tommy
    Grace, David
    Assessment of Coexistence Performance for WiMAX Broadband in High Altitude Platform Cellular System and Multiple-Operator Terrestrial Deployments2007Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, performance of providing WiMAX from High Altitude Platforms (HAPs) with multiple antenna payload will be investigated as well as considering the coexistence capability with multiple-operator terrestrial deployments. A scenario of a HAP and terrestrial WiMAX base stations deployed inside a HAP coverage area with a radius at 30 km will be proposed. HAP cellular formation with different reuse patterns will be established. Coexistence performance will be assessed in terms of HAP downlink signal interfered by terrestrial WiMAX deployment. This paper will show it is effective to deliver WiMAX via HAPs and can efficiently share the spectrum with terrestrial WiMAX systems.

  • 1352. Yang, Zhe
    et al.
    Mohammed, Abbas
    Hult, Tommy
    Grace, David
    Downlink Coexistence Performance Assessment and Techniques for WiMAX Services from High Altitude Platform and Terrestrial Deployments2008Ingår i: EURASIP Journal on Wireless Communications and Networking, ISSN 1687-1472, E-ISSN 1687-1499, Vol. 2008Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We investigate the performance and coexistence techniques for worldwide interoperability for microwave access (WiMAX) delivered from high altitude platforms (HAPs) and terrestrial systems in shared 3.5 GHz frequency bands. The paper shows that it is possible to provide WiMAX services from individual HAP systems. The coexistence performance is evaluated by appropriate choice of parameters, which include the HAP deployment spacing radius, directive antenna beamwidths based on adopted antenna models for HAPs and receivers. Illustrations and comparisons of coexistence techniques, for example, varying the antenna pointing offset, transmitting and receiving antenna beamwidth, demonstrate efficient ways to enhance the HAP system performance while effectively coexisting with terrestrial WiMAX systems.

  • 1353. Yang, Zhe
    et al.
    Mohammed, Abbas
    Hult, Tommy
    Grace, David
    Optimizing Downlink Coexistence Performance of WiMAX Services in HAP and Terrestrial Deployments in Shared Frequency Bands2007Konferensbidrag (Refereegranskat)
  • 1354.
    Yao, Yong
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    A Spectrum Decision Support System for Cognitive Radio Networks2012Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Cognitive Radio Networks (CRNs) offer a promising capability of alleviating the problem of spectrum insufficiency. In CRNs, the licensed spectrum channels are either exclusively reserved for licensed users or temporarily used by unlicensed users. The requirement for unlicensed users is to not harmfully impair the licensed users transmissions. Because of this, the unlicensed users must solve the task to decide which available channels should be selected. The selection process is often referred to as spectrum decision, with the aim to optimize the transmission performance of unlicensed users. A support system for CRNs is introduced, which is called Spectrum Decision Support System (SDSS). SDSS provides an intelligent spectrum decision strategy that integrates different decision making algorithms and takes into account various channel characterization parameters. The objective is to develop a scientific framework for decision making in CRNs, which involve theoretical analysis, simulation evaluation and practical implementation. Three important components of SDSS are discussed: 1) setting up an overlay decision maker, 2) prediction based spectrum decision strategy and 3) queuing modeling of CRNs. The reported results indicate the feasibility of the suggested algorithms.

  • 1355. Yao, Yong
    et al.
    Erman, David
    Popescu, Adrian
    Spectrum Decision for Cognitive Radio Networks2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    Cognitive Radio Networks (CRNs) are a key technology suggested to be part of 4G and beyond. The fundamental concept is to let Secondary Users (SUs) have temporal free access to spectrum bands not occupied by Primary Users (PUs). Since SUs are not allowed to cause harmful interference to PUs, SUs need to select the most available spectrum bands for access, also known as spectrum decision. In the paper, we suggest a middleware called Spectrum Decision Support System (SDSS) abstractly illustrated. The goal of SDSS is to combine the different decision methods together and to make intelligent band selection based upon partial characterizations of CRNs

  • 1356.
    Yao, Yong
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Ngoga, Said Rutabayiro
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Erman, David
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Popescu, Adrian
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Competition-Based Channel Selection for Cognitive Radio Networks2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    In cognitive radio networks, unlicensed users need to learn from environmental changes. This is a process that can be done in a cooperative or non-cooperative manner. Due to the competition for channel utilization among unlicensed users, the non-cooperative approach may lead to overcrowding in the available channels. This paper is about a fuzzy-logic based decision making algorithm for competition-based channel selection. The underlying decision criterion integrates both the statistics of licensed users' channel occupancy and the competition level of unlicensed users. By using such an algorithm, the unlicensed user competitors can achieve an efficient sharing of the available channels. Simulation results are reported to demonstrate the performance and effectiveness of our suggested algorithm.

  • 1357.
    Yao, Yong
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Ngoga, Said Rutabayiro
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Erman, David
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Popescu, Adrian
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Performance of Cognitive Radio Spectrum Access with Intra- and Inter-Handoff2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    Opportunistic spectrum access (OSA) is a technology that allows unlicensed users to access spectrum holes and to provide so efficient use of radio resources. Most of the studies done on OSA focus on the situation when the unlicensed user performs the spectrum handoff only within a single cognitive radio network (so-called intra-handoff). In this paper, we consider the users (licensed or unlicensed) to be able to do inter-handoff among different cognitive radio cells as well. The cells provide priority to inter-handoff users. By considering multiple cells being in steady-state, the arrival rates of inter-handoff users are determined. We study the OSA performance of unlicensed users under both intra- and inter-handoff schemes, with respect to the blocking and forced-termination probabilities of unlicensed users as well as the unlicensed user service-completion and inter-handoff throughputs. Our Markov chain based numerical analysis is validated by simulation experiments.

  • 1358.
    Yao, Yong
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Ngoga, Said Rutabayiro
    Popescu, Adrian
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    A System for Spectrum Decision in Cognitive Radio Networks2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    In Cognitive Radio (CR) networks, licensed radio channels are allowed to be used by Secondary Users (SUs) as long as SUs do not harmfully impair the transmission of Primary Users (PUs). Therefore, a crucial task for SUs is to decide which available channel should be selected, the so-called spectrum decision. To provide intelligent spectrum decision strategy to SUs, we suggest a system called Spectrum Decision Support System (SDSS). SDSS takes into account both heterogeneity aspects and interoperability requirements of CR networks. By this, SDSS is capable of jointly considering various channel characterizations and different decision making algorithms for doing spectrum decision. The paper is reporting the SDSS architecture as well as the related work-in-progress.

  • 1359.
    Yao, Yong
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Ngoga, Said Rutabayiro
    Popescu, Adrian
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Cognitive Radio Spectrum Decision Based on Channel Usage Prediction2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    The paper is about a new strategy suggested for spectrum decision in Cognitive Radio (CR) networks. By jointly considering sensing error, Secondary Users (SUs) competition and SUs transmission collision, a new parameter called Channel Usage State (CUS) is introduced. For a particular channel, we predict the respective probabilities of occurrence of CUS states by using the LeZi-update scheme. We also adopt a fuzzy comparison algorithm to combine the prediction results as a joint value. The largest joint value is associated with the most available channel for access by SUs in the near future. By comparing with random channel access, the suggested strategy can improve SUs transmission throughput. This is demonstrated by the simulation evaluations.

  • 1360.
    Yao, Yong
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Popescu, Adrian
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    On Energy Consumption in Mobile Multimedia Networks with OpenFlow Switch2016Ingår i: 2016 INTERNATIONAL CONFERENCE ON COMMUNICATIONS (COMM 2016), IEEE, 2016, s. 309-312Konferensbidrag (Refereegranskat)
    Abstract [en]

    In mobile multimedia networks, the video flow usually operates in an end-to-end manner from Head-End to mobile terminals. However, measuring the energy consumption associated with a video flow is a sophisticated process due to the complexity related to this. In the paper, a theoretical measurement approach is suggested to estimate the energy consumption of a video flow through mobile multimedia networks enhanced with the support of OpenFlow switch. Two different power models are built up to compute the traffic related energy consumption at the network element side. The numerical derivation of these two theoretical models is presented.

  • 1361.
    Yao, Yong
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datalogi och datorsystemteknik.
    Popescu, Adrian
    Blekinge Tekniska Högskola.
    On Energy Consumption in Mobile Multimedia Networks with OpwnFlow Switch2016Ingår i: International Conference on Communications (COMM), 2016, IEEE, 2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    With the advance of new wireless technologies and ubiquitous radio access, mobile multimedia is becoming a very important application for both service providers and end users. This also leads to different business models such as mobile television, mobile conferencing, and remote gaming. A Mobile Multimedia Network (MMN) generally refers to several parts, which are known as the video contribution, the network distribution and the mobile terminals. The video contribution is connected to the functions of generating and processing the video content, which is eventually transferred onto the network for further distribution to mobile terminals.

  • 1362.
    Yao, Yong
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datalogi och datorsystemteknik.
    Popescu, Adrian
    Blekinge Tekniska Högskola.
    Fiedler, Markus
    Blekinge Tekniska Högskola.
    Ljung, Rickard
    Sony Mobile Communications, SWE.
    On the Performance of Video Streaming in Energy-Aware Wireless Mesh Networks2017Ingår i: European Conference on Networks and Communications (EuCNC) 2017, IEEE, 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    Mobile multimedia has today become a promising application for end users and service providers. With reference to the existing systems for mobile communications, this application further demands for solving several technical problems, especially regarding video streaming over wireless networks. An interesting approach is in form ofWireless Mesh Network (WMN) based networks, where the individual video flows operate in an end-to-end (e2e) manner along a particular networking scenario including several mesh routers. That means, a particular mesh router may be traversed by multiple video flows. This situation may become even more complicated in the case of a large amount of packet retransmissions, which may deteriorate the performance of video flows. To investigate this problem, a two-level Modulated Markov Poisson Process (MMPP) based queueing model is built up and the transport performance of e2e video streaming in WMN based mobile multimedia system is analysed. Four metrics are used to study the system performance, namely e2e throughput, e2e delay, e2e error-rate and traffic-related energy consumption. Numerical analysis and evaluation studies are done. Based on the reported results, two different solutions are suggested and discussed with regard to the trade-off among these metrics.

  • 1363.
    Yao, Yong
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Popescu, Alexandru
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Ngoga, Said Rubatayiro
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Popescu, Adrian
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    On Prioritized Spectrum Access in Cognitive Radio Networks with Imperfect Sensing2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    Cognitive Radio networks allow the unlicensed users to share the available spectrum opportunities. However, this demands for solving the problem of contention among multiple unlicensed user packets for transmission. In our paper, we consider the Opportunistic Spectrum Access model for packet transmission between two unlicensed users. We suggest a priority scheme for a unlicensed user to concurrently transmit different types of packets. Our scheme reserves a fixed number of queueing places in the buffer for the prioritized packets. We study the transmission performance under both the priority scheme and imperfect spectrum sensing, with respect to the blocking probabilities, average transmission delay and transmission throughput of unlicensed users packets. The Markov chain based numerical analysis is validated by simulation experiments. Our results show that the suggested priority scheme is able to enhance transmission throughput of unlicensed users packets, together with significant decreased average transmission delay and minor decreased total transmission throughput.

  • 1364.
    Yao, Yong
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Popescu, Alexandru
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Popescu, Adrian
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    On Fuzzy Logic-Based Channel Selection in Cognitive Radio Networks2014Ingår i: Software-Defined and Cognitive Radio Technologies for Dynamic Spectrum Management / [ed] Kaabouch, Naima; Hu, Wen-Chen, Hershey, PA 17033, USA: IGI-Global , 2014Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Cognitive radio networks are a new technology based on which unlicensed users are allowed access to licensed spectrum under the condition that the interference perceived by licensed users is minimal. That means unlicensed users need to learn from environmental changes and to take appropriate decisions regarding the access to the radio channel. This is a process that can be done by unlicensed users in a cooperative or non-cooperative way. Whereas the non-cooperative algorithms are risky with regard to performance, the cooperative algorithms have the capability to provide better performance. Our paper reports therefore a new fuzzy logic based decision making algorithm for channel selection. The underlying decision criterion considers statistics of licensed users channel occupancy as well as information about the competition level of unlicensed users. Our theoretical studies indicate that the unlicensed users can obtain an efficient sharing of the available channels. Simulation results are reported to demonstrate the performance and effectiveness of the suggested algorithm.

  • 1365.
    Yao, Yong
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Popescu, Alexandru
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Popescu, Adrian
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    On prioritised opportunistic spectrum access in cognitive radio cellular networks2015Ingår i: European transactions on telecommunications, ISSN 1124-318X, E-ISSN 2161-3915, Vol. 27, nr 2, s. 294-310Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cognitive radio (CR) networks allow secondary users (SUs) to opportunistically access licensed spectrum, thus providing efficient use of radio resources. Different studies carried out on CR networks have focused on the procedure of spectrum handoff of SUs such as the data transmission in a communication that can be carried out in different channels. In this paper, we consider cellular networks enhanced with facilities for CR communication where a user with a call in progress moves across neighbouring cells, that is, the so-called inter-cell handoff. Our model assumes that the cell gives priority to inter-cell handoff calls over the calls originating within it. A finite queue is used in every cell for SUs, and a fixed number of buffer slots are reserved for the inter-handoff SU calls. With these considerations, we study the transmission performance of SUs by using Markov chains-based modelling approach. The numerical analysis is validated by simulation experiments. We also suggest a fuzzy logic-based hybrid decision-making algorithm to select the best solution for inter-handoff prioritisation. The goal is to optimise the transmission performance of SUs by leveraging their requirements on service completion throughput and waiting time in each cell. Copyright © 2014 John Wiley & Sons, Ltd.

  • 1366.
    Yarrapothu, Sindhura
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Effectiveness of Backup and Disaster Recovery in Cloud: A Comparative study on Tape and Cloud based Backup and Disaster Recovery2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Context: Backup and Disaster Recovery, DR play a vital role in day-to-day IT operations. They define extensive aspects of business continuity plan in an enterprise. There is a continuous need to improve backup and recovery performance concerning attributes such as backup window size, high availability, security, etc. Definitive information is what enterprises strive for and rely upon to deviate from traditional methods towards advancing technologies, which are an intrinsic segment of business mundane actions.

    Objectives: In this study, we investigate Backup and DR plans on an enterprise level. They are compared in terms of performance metrics such as Recovery Time Objective, Recovery Point Objective, Time taken to backup, Time taken to recover and Total cost of ownership. Also, how CPU and memory utilization conduct differ in both tape-based, cloud-based Backup and DR.

    Methods: Literature study was the first step to formulate research questions by understanding present technologies in Backup and DR. This led us to conduct a survey for further understanding of challenges faced in industries gaining a more practical exposure. A case study was conducted in an enterprise to capture accurate values. An experiment had been deployed to compare performance of both scenarios and analyze which methodology elevates Backup and DR performance by overcoming challenges.

    Results: The results attained through this thesis encompass performance related metrics and also the load in terms of CPU and memory utilizations. Survey results were observed to gain better understanding of current technologies and challenges with Backup and DR in enterprises. The cloudbased backup has proved to be better in considered enterprise environment during experimentation in terms of RPO, RTO, CPU, memory utilizations and Total Cost of ownership.

    Conclusions: There have been numerous research works conducted on how backup and DR plans can be made better. But, they lack accurate information on how their performances vary, what all parameters can be improved by shifting towards advanced and contemporary methodologies withaddressing features such as scalability, flexibility and adaptability, which is provided in this study.

  • 1367.
    Yasir, Mukhtar Muhammad
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Kamal, Badar Munir
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Issues In WiMax Handover2009Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    WiMax, the Worldwide Interoperability for Microwave Access is a new technology dealing with provision of data over long distance using wireless communication method in many different ways. Based on IEEE 802.16 WiMax is claimed as an alternative broadband rather than cable and DSL. In our thesis study we will findout the phenomenon and factors involved in WiMax handover and their effect on overall quality of service. We also intend to look into the solutions possible for those problems effecting WiMax QoS in handover. Handover is the main theme of wireless technolgy and it makes interoperability between diffrent network technologies and provides mobility. However there are some problems during handover and the problem in our focus will be handover delay. Handover delay if longer than expected makes the communication faulty and introduces errors and packet loss which in turns degrade QoS in WiMax

  • 1368. Yatawara, Yeshan
    et al.
    Caldera, Manora
    Kusuma, Tubagus Maulana
    Zepernick, Hans-Jürgen
    Unequal Error Protection for ROI Coded Images over Fading Channels2005Konferensbidrag (Refereegranskat)
    Abstract [en]

    Region of interest (ROI) coding is a feature supported by the Joint Photographic Experts Group 2000 (JPEG2000) image compression standard and allows particular regions of interest within an image to be compressed at a higher quality than the rest of the image. In this paper, unequal error protection (UEP) is proposed for ROI coded JPEG2000 images as a technique for providing increased resilience against the effects of transmission errors over a wireless communications channel. The hierarchical nature of an ROI coded JPEG2000 code-stream lends itself to the use of UEP whereby the important bits of the code-stream are protected with a strong code while the less important bits are protected with a weaker code. Simulation results obtained using symbol-by-symbol maximum a posteriori probability (MAP) decoding demonstrate that the use of UEP offers significant gains in terms of the peak signal to noise ratio (PSNR) and the percentage of readable files. Moreover, the use of ROI-based UEP leads to reduced computational complexity at the receiver.

  • 1369.
    Yazdani, Tulha Moaiz
    et al.
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för telekommunikationssystem.
    Islam, Munawar
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för telekommunikationssystem.
    Design And Fabrication Of A Microstrip Antenna For WI-MAX Applications2008Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Worldwide Interoperability for Microwave Access (Wi-Max) is a broadband technology enabling the delivery of last mile (final leg of delivering connectivity from a communication provider to customer) wireless broadband access (alternative to cable and DSL). It should be easy to deploy and cheaper to user compared to other technologies. Wi-Max could potentially erase the suburban and rural blackout areas with no broadband Internet access by using an antenna with high gain and reasonable bandwidth Microstrip patch antennas are very popular among Local Area Network (LAN), Metropolitan Area Network (MAN), Wide Area Network (WAN) technologies due to their advantages such as light weight, low volume, low cost, compatibility with integrated circuits and easy to install on rigid surface. The aim is to design and fabricate a Microstrip antenna operating at 3.5GHz to achieve maximum bandwidth for Wi-Max applications. The transmission line model is used for analysis. S-parameters (S11 and S21) are measured for the fabricated Microstrip antenna using network analyzer in a lab environment. The fabricated single patch antenna brings out greater bandwidth than conventional high frequency patch antenna. The developed antenna also is found to have reasonable gain.

  • 1370.
    Yellakonda, Amulya
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    DESIGN AND IMPLEMENTATION OF RICH COMMUNICATION SERVICE SCENARIO REPLAYER AND PERFORMANCE EVALUATION OF APPLICATION SERVICE2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Rich Communication Services(RCS) program is a GSM Association (GSMA) initiative to create inter-operator communication services based on IP Multimedia Subsystem (IMS) . This initiative came up as the Global Telecom Operators ́response to the decline in their revenues and to help compete ’Over The Top’(OTT) service providers such as Viber, whatsapp, etc. RCS is an universal standard, making it inter-operable between mul- tiple service providers unlike OTT services with closed communities. RCS services use IMS as the underlying architecture with a RCS stack imple- mented into Android background service which offers high level API. For the purpose of testing RCS stack functionality which is usually affected by external dependencies like third party vendors, or ISP customizations in real telecommunication scenario, there is a persistent demand for scenario replay tools that can recreate the range of test conditions similar to those experienced in live deployments. There is also a need to evaluate the per- formance of service provided by application servers in the network in-order to predict the factors affecting the RCS service in general.

    In this work, we propose a tool to address the RCS scenario repro- duction in a test environment. The tool is implemented within an automated test environment with full control on interaction with the RCS stack, hence the ability to replay the scenario in a controlled fashion. To achieve the goal, the tool replays trace interactively with the RCS stack in a stateful manner , it ensures no improper packet generation which is critical feature for test environments where protocol semantics accuracy is fundamental. A detailed demonstration of how the tool can be deployed in test environ- ments is stated. A novel approach is used to validate the effectiveness of the replayed scenario, the sequence of events and states are compared to those from the recorded scenario using a call-back service to indicate the state. The replayed scenario showed strong relationship with the recorded RCS scenario. The paper also presents a performance evaluation of Application service by considering the request-reponse times of Network Registration procedure. The obtained results show that the average time taken for the Registration process is 555 milliseconds and in few instances there exists larger deviations from this average value showing the faulty behavior of the Server which is most crucial during the debugging process for the developers. 

  • 1371. Yeoh, Phee
    et al.
    Elkashlan, Maged
    Yang, Nan
    Benevides Da Costa, Daniel
    Duong, Quang Trung
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    MIMO multi-relay networks with TAS/MRC and TAS/SC in Weibull fading channels2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    We examine transmit antenna selection with receiver maximal-ratio combining (TAS/MRC) and transmit antenna selection with receiver selection combining (TAS/SC) in multiple-input multiple-output (MIMO) relay networks. Amongst L two-hop relay links, a single relay offering the highest end-to-end signal-to-noise ratio (SNR) is activated. Assuming independent non-identically distributed Weibull fading between the hops, new closed-form asymptotic expressions for the outage probability and the symbol error rate are derived considering NS, NR, and ND antennas at the source, the relays, and the destination, respectively. Based on such expressions, the diversity order and the array gain for M-ary phase shift keying and M-ary quadrature amplitude modulation are analyzed. We highlight that the diversity order of TAS/MRC is the same as TAS/SC. As such, we explicitly characterize the SNR gap between TAS/MRC and TAS/SC as the ratio of their respective array gains. An interesting observation is reached that for equal per-hop SNRs, the SNR gap between the two protocols is independent of L.

  • 1372. Yeoh, Phee Lep
    et al.
    Elkashlan, Maged
    Yang, Nan
    da Costa, Daniel B.
    Duong, Quang Trung
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Unified Analysis of Transmit Antenna Selection in MIMO Multi-Relay Networks2013Ingår i: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 62, nr 2Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present a unified asymptotic framework for transmit antenna selection in multiple-input multiple-output (MIMO) multi-relay networks with Rician, Nakagami-m, Weibull, and Generalized-K fading channels. We apply this framework to derive new closed-form expressions for the outage probability and symbol error rate (SER) of amplify-andforward relaying in MIMO multi-relay networks with two distinct protocols: 1) transmit antenna selection with receiver maximalratio combining (TAS/MRC), and 2) transmit antenna selection with receiver selection combining (TAS/SC). Based on these expressions, the diversity order and the array gain with M-ary phase shift keying and M-ary quadrature amplitude modulation are derived.We corroborate that the diversity order only depends on the fading distribution and the number of diversity branches, whereas the array gain depends on the fading distribution, the modulation format, the number of diversity branches, and the average per-hop signal-to-noise ratios (SNRs). We highlight that the diversity order of TAS/MRC is the same as TAS/SC, regardless of the underlying fading distribution. As such, we explicitly characterize the SNR gap between TAS/MRC and TAS/SC as the ratio of their respective array gains. An interesting observation is reached that for equal per-hop SNRs, the SNR gap between the two protocols is independent of the number of relays.

  • 1373. Yeoh, Phee Lep
    et al.
    Elkashlan, Maged
    Yang, Nan
    da Costa, Daniel
    Duong, Quang Trung
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Unified Analysis of Transmit Antenna Selection in MIMO Multirelay Networks2013Ingår i: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 62, nr 2, s. 933-939Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present a unified asymptotic framework for transmit antenna selection in multiple-input multiple-output (MIMO) multirelay networks with Rician, Nakagami-m, Weibull, and generalized-K fading channels. We apply this framework to derive new closed-form expressions for the outage probability and symbol error rate (SER) of amplify-and-forward (AF) relaying in MIMO multirelay networks with two distinct protocols: 1) transmit antenna selection with receiver maximal-ratio combining (TAS/MRC) and 2) transmit antenna selection with receiver selection combining (TAS/SC). Based on these expressions, the diversity order and the array gain with M-ary phase-shift keying and M-ary quadrature-amplitude modulation are derived. We corroborate that the diversity order only depends on the fading distribution and the number of diversity branches, whereas the array gain depends on the fading distribution, the modulation format, the number of diversity branches, and the average per-hop signal-to-noise ratios (SNRs). We highlight that the diversity order of TAS/MRC is the same as TAS/SC, regardless of the underlying fading distribution. As such, we explicitly characterize the SNR gap between TAS/MRC and TAS/SC as the ratio of their respective array gains. An interesting observation is reached that for equal per-hop SNRs, the SNR gap between the two protocols is independent of the number of relays.

  • 1374.
    Yong, Yao
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Adrian, Popescu
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    On Prioritized Uplink Transmission in Cognitive Radio Mesh Networks2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    In cognitive radio mesh networks, the unlicensed users are allowed to use spectrum opportunities under the restriction of protection of licensed users. The transmission operation of unlicensed users packets is typically done through multiple mesh routers. In the case of a large amount of packet retransmissions, the performance of the whole network system may degrade. To solve this problem, a queueing buffer based priority scheme for mesh routers is suggested. Based on this scheme, the uplink transmission performance of unlicensed users in cognitive radio mesh networks is studied under the condition of imperfect spectrum sensing. 

  • 1375.
    Yong, Yao
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Adrian, Popescu
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    On the Performance of Uplink Transmission in Cognitive Radio Mesh Networks2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    In cognitive radio mesh networks, the unlicensed users are allowed to use spectrum opportunities under the restriction of protection of licensed users. The transmission operation of unlicensed users packets is typically done through multiple mesh routers. In the case of a large amount of packet retransmissions, the performance of the whole network system may degrade. To solve this problem, a queueing buffer based priority scheme for mesh routers is suggested. Based on this scheme, the uplink transmission performance of unlicensed users in cognitive radio mesh networks is studied under the condition of imperfect spectrum sensing. Numerical evaluation results show the feasibility and effectiveness of the suggested priority scheme. 

  • 1376.
    Yousefi, Erfan
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för elektroteknik.
    Farhat, Nasrin
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för elektroteknik.
    Antenna Performance Software2013Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Antenna performance software is a tool to measure the quality and enactment of the newly developed products. This is an important matter to the development department of the company since the products must be verified to work with regarding to the user specifications.

    Using LabView, this tool has been developed in order to provide ease for this test. This software has been compared with previous solutions given and has been optimized to be able to do the tests successfully. 

  • 1377.
    Yousuf, Kamran
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Time controlled network traffic shaper2010Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Network performance metrics such as delay variations and packet loss influence the performance of the network. As a consequence, the performance of applications on the network is also affected as most of the networked applications existing today are very much sensitive to the network performance. Therefore it is of utmost importance to test the intensity of such network level disturbances on the performance of applications. A network traffic shaper/emulator shapes the network traffic in terms of these performance metrics to test such applications in a controlled environment. Most of the traffic shapers existing today give the instantaneous step transition in delay and packet loss on network. In this work, we present time-controlled network traffic shaper, a tool that facilitates testing and experimentation of network traffic through emulation. It focuses on time variant behavior of the traffic shaper. A linear transition of delay and packet loss that is varying with respect to time may fits much better to the real network scenarios instead of an instantaneous step transition in delay and packet loss. This work illustrates the emulation capabilities of time-controlled network traffic shaper and presents its design architecture. Several approaches are analyzed to do the task and one of them is followed to develop the desired architecture of the shaper. The shaper is implemented in a small scenario and is tested to see whether the desired output is achieved or not. The shortfalls in the design of the shaper are also discussed. Results are presented that show the output from the shaper in graphical form. Although the current implementation of the shaper does not provide linear or exponential output but this can be achieved by implementing a configuration setting that is comprised of small transition values that are varying with respect to very small step sizes of time e.g. transitions on milli seconds or micro seconds. The current implementation of the shaper configuration provides the output with a transition of one milli second on every next second.

  • 1378.
    Yu, Jhang Shih
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Optimal Power Control in Cognitive Radio Networks with Fuzzy Logic2010Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    In this thesis, we consider a pair of primary link (PU link) and a pair of cognitive link (CR link) in a fading channel. The PU link and CR link share spectrum simultaneously with different priorities, establishing the spectrum sharing network. The PU link has a higher priority to utilize spectrum with respect to the CR link. A desired quality of service (QoS) is given as a threshold on the PU link when it utilizes spectrum. The CR link utilizes spectrum only when the PU link is assured with the desired QoS or recognized as idle, not utilizing spectrum. Under this constraint, the CR link utilizes spectrum with an opportunistic power scale to assure the desired QoS on the PU link. To optimize the spectrum usage, we propose a fuzzy-based optimal power control strategy for the CR link using Mamdani fuzzy control. With the proposed control strategy, the CR link can estimate an optimal power scale for the spectrum sharing network.To illustrate the proposed fuzzy-based optimal power control strategy and its advantages, we approach the spectrum sharing network in two different propagation environments: without path loss and with path loss. In the propagation environment without path loss, we assume all channel state information (CSI) on each transmission side is available to the others, including the PU’s signal-to-noise (PU’s SNR) and PU’s interference channel gain . These two variables are used as fuzzy antecedents to estimate a corresponding power scale. In the propagation environment with path loss, we analyze the spectrum sharing network from the geometric point of view. We assume all CSI on each side is available to the others, including the PU’s SNR, PU’s interference channel gain and relative distance is fixed and normalized to 1, we use PU’s SNR and relative distance as fuzzy antecedents to calculate a corresponding power scale.

  • 1379.
    Yves, Hawa
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för signalbehandling.
    A Study of Fast Backprojection Algorithm for UWB SAR and a Comparison between Fast- and Global Backprojection2008Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    In this thesis, we present a study of the Fast Backprojection (FBP) known to be a fast time-domain algorithm for image retrieval in Synthetic Aperture Radar (SAR). As a time domain algorithm, FBP possesses inherent advantages such as perfect motion compensation, unlimited scene size, wide bandwidth and ability to handle long integration angles. Although FBP reproduces SAR images on pixel-by-pixel basis, the processing time for FBP is reduced significant compared to the Global Backprojection (GBP) with a heavy computational load. For GBP, the number of operations to process a N×N SAR image with N aperture positions is proportional to N . Whereas, the number of operation required by FBP in the same case is reduced by a factor of sqrt(N) i.e. proportional to N2sqrt(N). We give a detailed explanation on how to implement FBP in Matlab in order to retrieve a SAR image. We explain about different techniques of interpolation used to obtain a high quality image. We also present a method to compare between interpolation techniques in term of SAR image quality and processing time. A comparison between FBP and GBP is also a topic to be discussed in this thesis. In this comparison, the processing time in theory and reality will be focused.

  • 1380.
    Yılmazer, Şafak Enes
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Integrated Coverage Measurement and Analysis System for Outdoor Coverage WLAN2011Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Daily usage of Wireless Local Area Networks (WLAN) in business life for specific purposes has became much more critical than before since it is sometimes crucial to have wireless connectivity and seamless roaming around the working environment. In this thesis, steps required in order to design and implement a large scale outdoor IEEE 802.11g WLAN will be shown. This WLAN project has been deployed in north of Sweden and target coverage was an open area consisting of a deep pit mine, connecting roads, workshops, offices, dumps and storage areas. All telecommunications equipment used in this project is from the manufacturer Cisco using centralized solution. The special purpose of this project is to collect and analyze a series of coverage measurement data and correlate this data to predict the coverage area. Linux bash scripting and Gnuplot has been used to analyze coverage data. Finally, WRAP spectrum management and radio planning software has been used in modeling and designing of the whole network.

  • 1381.
    Zaahid, Mohammed
    Blekinge Tekniska Högskola.
    Performance Metrics Analysis of GamingAnywhere with GPU acceletayed NVIDIA CUDA using gVirtuS2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The modern world has opened the gates to a lot of advancements in cloud computing, particularly in the field of Cloud Gaming. The most recent development made in this area is the open-source cloud gaming system called GamingAnywhere.

    The relationship between the CPU and GPU is what is the main object of our concentration in this thesis paper. The Graphical Processing Unit (GPU) performance plays a vital role in analyzing the playing experience and enhancement of GamingAnywhere. In this paper, the virtualization of the GPU has been concentrated on and is suggested that the acceleration of this unit using NVIDIA CUDA, is the key for better performance while using GamingAnywhere. After vast research, the technique employed for NVIDIA CUDA has been chosen as gVirtuS.

    There is an experimental study conducted to evaluate the feasibility and performance of GPU solutions by VMware in cloud gaming scenarios given by GamingAnywhere. Performance is measured in terms of bitrate, packet loss, jitter and frame rate. Different resolutions of the game are considered in our empirical research and our results show that the frame rate and bitrate have increased with different resolutions, and the usage of NVIDIA CUDA enhanced GPU.

  • 1382.
    Zafar, Muhammad-Sarfraz
    et al.
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för telekommunikationssystem.
    Gill, Muhammad-Shoaib
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för telekommunikationssystem.
    Evaluation of UDP and SCTP for SIP-T and TCP, UDP and SCTP with constant traffic2009Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    In recent years, Voice over IP (VoIP) has gained a lot of popularity. Signaling being an important part of VoIP has been addressed by the (IETF) SIGTRAN working group to meet Quality of Service as given by Public Switched Telephone Network (PSTN), so that both PSTN and VoIP can co-exit and work together in a seamless manner SIP (Session Initiation Protocol) developed by IETF for VoIP signaling is a communication control protocol capable of running on different transport layers, e.g., TCP, UDP or SCTP. Today’s SIP application is mostly operating over the unreliable transport protocol UDP. In lossy environment such as wireless networks and congested Internet networks, SIP messages can be lost or delivered out of sequence. The SIP application then has to retransmit the lost messages and re-order the received packets. This additional processing overhead can degrade the performance of the SIP application. Therefore to solve this problem, the researchers are looking for a more appropriate transport layer for SIP. SCTP, a transport protocol providing acknowledged, error-free, non-duplicated transfer of messages, has been proposed to be an alternative to UDP [1] and TCP [2]. The multi-streaming and multi-homing features of SCTP are especially attractive for applications that have stringent performance and high reliability requirements and an example is the SIP proxy server. In this research, we have analyzed the performance offered by SCTP for SIP message delivery in the perspective of historic research work as well as determined call setup time using UDP and SCTP by simulating SIP traffic in Network Simulator-2 (ns-2). We also evaluate TCP, UDP and SCTP traffic with constant bit rate of traffic through ns-2

  • 1383.
    Zahoor, Amir
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Koodtalang, Wittaya
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Visual Quality Improvement of Digital Video by Stabilization Using Adaptive CMAC Filtering2013Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    A Digital Video Stabilization (DVS) system removes the unwanted shaking in the videos acquired by hand-held cameras and preserves the panning. In this thesis work, a digital video stabilization model is proposed based upon adaptive cerebellar model articulation controller (CMAC) filtering. A CMAC is a manifestation of the associative memory learning structure present in the cerebellum of human being. Adaptive CMAC filtering has favorable properties of small size, good generalization, rapid learning and dynamic response. So, it is more suitable for high-speed signal processing applications. The adaptive CMAC is used to adjust the coefficients of IIR filter employed in the proposed model. The training of CMAC is based upon a fuzzy rule. The efficiency of the proposed adaptive CMAC filtering has been validated by evaluating it on a set of test videos sequences. We have done performance comparison of CMAC algorithm with already existing algorithms such Kalman filter, Modified proportional integrated (MPI) controller and adaptive fuzzy filtering in terms of smooth index (SI), peak signal to noise ratio (PSNR), mean square error (MSE) and point spread function (PSF).

  • 1384.
    Zar, Abu
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    Asghar, Raja Abid
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap.
    MATLAB SIMULATOR FOR ADAPTIVE FILTERS2013Självständigt arbete på grundnivå (kandidatexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Adaptive filters play an important role in modern day signal processing with applications such as noise cancellation, signal prediction, adaptive feedback cancellation and echo cancellation. The adaptive filters used in our thesis, LMS (Least Mean Square) filter and NLMS (Normalized Least Mean Square) filter, are the most widely used and simplest to implement. The application we tested in our thesis is noise cancellation. A detail study of both filters is done by taking into account different cases. Broadly test cases were divided into two categories of stationary signal and non-stationary signal to observe performance against the type of signal involved. Noise variance was another factor that was considered to learn its effect. Also parameters of adaptive filter, such as step size and filter order, were varied to study their effect on performance of adaptive filters. The results achieved through these test cases are discussed in detail and will help in better understanding of adaptive filters with respect to signal type, noise variance and filter parameters.

  • 1385.
    Zasad, Muhammad Rabiul
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Uddin, Jia
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Study and Performance Comparison of MANET Routing Protocols:TORA, LDR and ZRP.2010Självständigt arbete på avancerad nivå (masterexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    Ad-hoc network has opened a new dimension in wireless networks. It allows wireless nodes to communicate with each other in the absence of centralised support. It does not follow any fixed infrastructure because of the mobility of nodes and multi-path propagations. Link instability and node mobility make routing a core issue in MANETs. A suitable and effective routing mechanism helps to extend the successful deployment of MANETs. In this thesis, we have studied details of TORA, LDR and ZRP routing protocols which are routing protocols on use in MANET. The effects on the routing efficiencies with a special focus on the pause time, scalability and node density using throughput, network load, end-to-end delay and packet delivery ratio as indices of performance evaluation for FTP traffic were observed by using OPNET 14.0 modular as simulation tool. Based on our observations from literature and empirical study conducted using OPNET, we have found that among the three protocols, no single protocol can successfully provide optimum efficiency in different MANET scenarios.

  • 1386.
    Zepernick, Hans-Juergen
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kreativa teknologier. Blekinge Inst Technol, SE-37179 Karlskrona, Sweden..
    Toward Immersive Mobile Multimedia: Opportunities, Challenges, and Enablers2018Ingår i: 2018 12TH INTERNATIONAL CONFERENCE ON SIGNAL PROCESSING AND COMMUNICATION SYSTEMS (ICSPCS) / [ed] Wysocki, TA Wysocki, BJ, IEEE , 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    In recent years, we have seen an increasing interest in immersive mobile multimedia applications and services. Advanced human-machine interfaces (HMIs) and related head-mounted displays (HMDs) support different levels of computer-generated virtual worlds. These worlds include mobile virtual reality (VR), mobile augmented reality (VR), and mobile mixed reality (MR) which are jointly captured under the term mobile extended reality (XR). In addition, the development of fifth generation (5G) mobile networks aims at catering for ultra-reliable low-latency communications such as mobile XR and the tactile Internet. In this context, 5G mobile networks are essential enablers to carry mobile XR beyond video gaming to the general consumer and industry markets. In this keynote lecture, the fundamentals of interconnected immersive mobile multimedia are reviewed, and opportunities, challenges, and enablers are discussed. An overview of immersive mobile multimedia from mobile video to mobile 360-degree video, mobile VR, mobile AR, mobile MR, and mobile XR is provided. Major components of interconnected immersive mobile multimedia will be discussed and application opportunities in different vertical industries are pointed out. Furthermore, challenges associated with the delivery of immersive mobile XR applications are shown through service integrity parameters. Several enablers for interconnected immersive mobile multimedia applications are highlighted including standardization activities.

  • 1387.
    Zepernick, Hans-Juergen
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kreativa teknologier.
    Chu, Thi My Chinh
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kreativa teknologier.
    Descriptive Statistical Analysis of Subjective Experiments in Mobile Imaging2017Ingår i: 11th International Conference on Signal Processing and Communication Systems, ICSPCS 2017 / [ed] Wysocki, TA Wysocki, BJ, IEEE , 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we provide a descriptive statistical analysis of subjective experiments in mobile imaging. Most of the statistical analyses of such experiments use condensed statistics such as mean opinion scores along with standard deviations. These statistics give only limited insights on the underlaying distribution of a data set. On the other hand, higher order statistics such as skewness and kurtosis provide additional information about a distribution but their qualitative interpretation is complicated. In order to alleviate these shortcomings, we advocate the use of box plots to efficiently visualize and compare distributions between different sets of image quality scores. Specifically, box plots serve the purposes of accounting for the diversity in image quality scores as well as supporting an intuitive qualitative interpretation of the results. It is shown by analysing two subjective experiments of the wireless imaging quality database that notched box plots are beneficial in quickly assessing the statistical significance among differences in such experiments. Further, box plots are used to identify those test material that received a wide diversity in image quality scores including outliers.

  • 1388.
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Quality of Mobile Multimedia Experience: Past, Present and Future2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    The rapid evolution of wireless networks is driven by the growth of wireless packet data applications such as interactive mobile multimedia applications, wireless streaming services, and video-on-demand. The largely heterogeneous network structures, severe channel impairments, and complex traffic patterns make the wireless networks much more unpredictable compared to their wired counterparts. One of the major challenges with the roll-out of these services is therefore the design of wireless networks that fulfill the stringent quality of service requirements of mobile multimedia applications. In this tutorial, we provide a survey on the evolution of quality of experience (QoE) concepts in the context of mobile multimedia systems touching on the past, present, and future aspects. Specifically, the ideas behind QoE are discussed and an overview of related standardization work and major research initiatives is provided. On this basis, QoE metrics for speech, image, and video are described. Given the increase on visual services, perceptual image and video quality metrics for real-time quality assessment of mobile multimedia experience are discussed. This includes a classification of quality assessment methods, comparison of psychophysical versus engineering approaches, perceptual image and video quality assessment, and some example applications. An outlook on future work and challenges is also provided.

  • 1389.
    Zepernick, Hans-Jürgen
    et al.
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för signalbehandling.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för telekommunikationssystem.
    Lundberg, Lars
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för programvarusystem.
    Pettersson, Mats
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för signalbehandling.
    Quality of Experience Based Cross-Layer Design of Mobile Video Systems2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper introduces and discusses quality of experience based cross-layer design of mobile video systems as a means of providing technologies for jointly analyzing, adopting, and optimizing system quality. The many benefits of our novel approaches over traditional concepts will range from efficient video processing techniques over advanced real-time scheduling algorithms, to networking and service level management techniques. This will lead to better service quality and resource utilization in mobile video systems.

  • 1390. Zhao, Fan
    et al.
    Shin, Yongjoo
    Wu, Felix
    Johnson, Henric
    Nilsson, Arne A.
    RBWA: an efficient random-bit window-based authentication protocol2003Konferensbidrag (Refereegranskat)
    Abstract [en]

    Given the wide and rapid depolyment of "visitor networks", how to authenticate the user and account the usage on the per-packet basis securely and yet efficiently is still a challenging problem. In this paper, we explore the tradoff between performance and security, and propose a per-data-packet authentication and access control called RBWA (Random Bit Window based Authentication). Deployed in the IP layer, RBWA can work with various underlying link layer specific mechanisms and network topologies. And comparing to IPSec, it dramatically reduces the overhead and power consumption by adding only a few bits to each packet. Furthermore, RBWA is strong against a suite of attacks such as replay attack, Denial-of-Service attack and spoofing etc. In particular, a robust anti-replay window scheme is developed to counter the svere packet reordering. The performance of RBWA is evaluated via the simulation.

  • 1391. Zheng, Zhibo Pang
    et al.
    Zheng, Lirong
    Tian, Junzhe
    Kao-Walter, Sharon
    Blekinge Tekniska Högskola, Fakulteten för teknikvetenskaper, Institutionen för maskinteknik.
    Dubrova, Elena
    Chen, Qian
    Design of a terminal solution for integration of in-home health care devices and services towards the Internet-of-Things2015Ingår i: Enterprise Information Systems, ISSN 1751-7575, E-ISSN 1751-7583, Vol. 9, nr 1, s. 86-116Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In-home health care services based on the Internet-of-Things are promising to resolve the challenges caused by the ageing of population. But the existing research is rather scattered and shows lack of interoperability. In this article, a business-technology codesign methodology is proposed for cross-boundary integration of in-home health care devices and services. In this framework, three key elements of a solution (business model, device and service integration architecture and information system integration architecture) are organically integrated and aligned. In particular, a cooperative Health-IoT ecosystem is formulated, and information systems of all stakeholders are integrated in a cooperative health cloud as well as extended to patients’ home through the inhome health care station (IHHS). Design principles of the IHHS includes the reuse of 3C platform, certification of the Health Extension, interoperability and extendibility, convenient and trusted software distribution, standardised and secured electrical health care record handling, effective service composition and efficient data fusion. These principles are applied to the design of an IHHS solution called iMedBox. Detailed device and service integration architecture and hardware and software architecture are presented and verified by an implemented prototype. The quantitative performance analysis and field trials have confirmed the feasibility of the proposed design methodology and solution.

  • 1392. Zhou, Kaibo
    et al.
    Liu, Gang
    Yao, Yong
    Popescu, Adrian
    A Mobility Management Solution for Simultaneous Mobility with mSCTP2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    The paper is about mobile Stream Control Transmission Protocol (mSCTP) and the problems related to simultaneous mobility. Simultaneous mobility is when the both endpoints of a communication session are mobile and they move at about the same time. mSCTP works well in the case of non-simultaneous mobility where the SCTP association is established between a mobile endpoint and a stationary one. In the case of simultaneous mobility however, the probability of broken association may become high because both endpoints may suffer from losing address binding update. This is a consequence of the fact that the targeted addresses become unreachable. In this paper, we suggest a solution based on Host Name Address (HNA), together with pro-active Name Server, Address Handling Function (AHF) and Simultaneous Mobility Detection Function (SMDF) to eliminate this problem. Our preliminary results show that the performance of our solution is as good as for non-simultaneous mobility situation in terms of packet loss rate for low rate stream. On the other hand, the drawback is that some modifications to the current standard mSCTP are needed.

  • 1393. Zhu, Chunsheng
    et al.
    Yang, Laurence T.
    Shu, Lei
    Duong, Quang Trung
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för telekommunikationssystem.
    Nishio, Shojiro
    Secured Energy-aware Sleep Scheduling Algorithm in Duty-cycled Sensor Networks2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    Sleep scheduling algorithms for duty-cycled sensor networks have received great attention, since sensors should dynamically awake and asleep to save energy consumption. Among all current sleep scheduling algorithms, only the recently proposed energy consumed uniformly-connected k-neighborhood (EC-CKN) algorithm focuses on not only the coverage of the resultant network, but also the network lifetime after sleep scheduling. However, all sleep scheduling processes ignore the fact that potential insider attacks actually can seriously affect or destroy proper sleep scheduling operations and properties. In this paper, we discuss these vulnerabilities and propose corresponding countermeasures for EC-CKN, i.e., secure neighborhood authentication

  • 1394. Zinner, Thomas
    et al.
    Hossfeld, Tobias
    Minhas, Tahir Nawaz
    Fiedler, Markus
    Controlled vs. Uncontrolled Degradations of QoE: The Provisioning-Delivery Hysteresis in Case of Video2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper applies the recently proposed provisioning-delivery hysteresis for Quality of Experience (QoE) to the case of video. The study is based on evaluations using the Structural Similarity Metric (SSIM) for different versions of a video in terms of resolution on one hand, and suffering from different packet loss ratios on the other hand. Upon translation of the SSIM into MOS, the QoE plotted versus the effective throughput shows the predicted behaviour: a controlled quality and throughput reduction leads to a better user perceived quality than the quality degradation due to packet loss. The results clearly quantify the necessity to control quality, instead of "getting hit" in an uncontrolled way.

  • 1395. Östlin, Erik
    et al.
    Suzuki, Hajime
    Zepernick, Hans-Jürgen
    Comparisons and Evaluation of ITU-R Recomendation P.1546 Versions2006Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, the validity of P.1546, in short range (typically less than 20km) terrestrial environment is analysed by comparing its three versions (P.1546, P.1546-1, and P.1546-2) against simple models and against measurement results obtained by utilising the pilot signal of a commercial CDMA mobile network in rural Australia. The results show that the latest version on average underestimates the field strength by more than 10 dB for typical Australian rural areas, however it improves the error standard deviation. The causes of these effects and the suggestions for further development of the Recommendation are discussed.

  • 1396. Östlin, Erik
    et al.
    Suzuki, Hajime
    Zepernick, Hans-Jürgen
    Evaluation of the propagation model Recommendation ITU-R P. 1546 for mobile services in rural Australia2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, the validity of Recommendation ITU-R P.1546 in a short-range terrestrial environment is analyzed. Its three versions (P.1546, P.1546-1, and P.1546-2) are compared against simple models and evaluated using measurement results that were obtained by utilizing the pilot signal of a commercial code-division multiple-access mobile telephone network. Measurement results show that P.1546-2, on average, underestimates the field strength by more than 10 dB for typical Australian rural areas. However, it improves the error standard deviation compared to previous versions. The causes of these effects and the suggestions for further development of the Recommendation are discussed and evaluated.

  • 1397. Östlin, Erik
    et al.
    Zepernick, Hans-Jürgen
    Suzuki, Hajime
    Evaluation of a New Effective Antenna Height Definition in ITU-R Recommendation P.1546-12005Konferensbidrag (Refereegranskat)
    Abstract [en]

    The International Telecommunication Union has recently developed a new Recommendation on the method of point-to-area predictions for terrestrial services in the frequency range 30MHz to 3000 MHz. It supersedes well-known Recommendations such as P.370 and P.529 (modified Okumura-Hata method) used mainly for broadcasting and mobile services, respectively. The Recommendation serves as a standard in areas of spectrum management and radio technology and is constantly under development. The work is undertaken by the ITU-R Working Party 3K followed by an extensive international approval process. At the moment, P.1546-1 incorporates an effective antenna height concept similar to that in the Okumura model. It is well known that this definition for certain scenarios produces negative transmitting/base antenna height values leading to unrealistic prediction results. Therefore, a widely accepted alternative method is called for. In this paper, an effective antenna height definition that overcomes this problem is investigated. The prediction results are compared with measurement data obtained by utilising the IS-95 pilot signal of a commercial CDMA mobile network in rural Australia.

  • 1398. Östlin, Erik
    et al.
    Zepernick, Hans-Jürgen
    Suzuki, Hajime
    Small-Scale Fading Prediction Using an Artificial Neural Network2005Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper proposes and evaluates an artificial neural network used for prediction of the Ricean K-factor. The model is trained with measurement data obtained by utilising the IS-95 pilot signal of a commercial CDMA mobile network in rural Australia. The neural network inputs are chosen to be distance to base station, parameters easily obtained from terrain path profiles and a clutter parameter extracted from a vegetation density data base. The Ricean K-factor indicates the small-scale fading margin required in a link budget calculation scenario, where pessimistic modelling, assuming Rayleigh fading, would lead to unnecessary high base station transmitter power and possible interference problems. The statistical analysis shows that the artificial neural network can be applied to accurately predict variations in the small-scale fading characteristics due to different terrain and vegetation.

  • 1399.
    Özcan, Mehmet Batuhan
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Iro, Gabriel
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    PARAVIRTUALIZATION IMPLEMENTATION IN UBUNTU WITH XEN HYPERVISOR2014Självständigt arbete på grundnivå (kandidatexamen)Studentuppsats (Examensarbete)
    Abstract [en]

    With the growing need for efficiency, cost reduction, reduced disposition of outdated electronics components as well as scalable electronics components, and also reduced health effects of our daily usage of electronics components. Recent trend in technology has seen companies manufacturing these products thinking in the mentioned needs when manufacturing and virtualizations is one important aspect of it. The need to share resources, the need to use lesser workspace, the need to reduce cost of purchase and manufacturing are all part of achievements of virtualization techniques. For some people, setting up a computer to run different virtual machines at the same time can be difficult especially if they have no prior basic knowledge of working in terminal environment and hiring a skilled personnel to do the job can be expensive. The motivation for this thesis is to help people with little or no basic knowledge on how to set up virtual machine with Ubuntu operating system on XEN hypervisor.

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