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  • 1.
    Akpotor Scott, Johnson
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Integrating Trust-Based Adaptive Security Framework with Risk Mitigation to enhance SaaS User Identity and Access Control based on User Behavior2022Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In recent years, the emerging trends in cloud computing technologies have given rise to different computing services through the Internet. Organizations across the globe have seized this opportunity as a critical business driver for computing resource access and utilities that will indeed support significant business operations. Embracing SaaS as a crucial business factor enhances corporate business strategy through economies of scale, easy manageability, cost-effectiveness, non-geographical dependence, high reliability, flexible resources, and fast innovation. However, this has also come with various risks due to the limitation of traditional user identity and access control solutions’ inability to effectively identify and manage cloud users’ authorization process when interacting with the cloud. The limit can result in a legitimate user account's impersonation to carry out malicious activities after the user account is compromised to go undetected since traditional solutions seldom function based on user behavior trust level behind any account.

    Furthermore, the limitation is a significant vulnerability to the cloud environment. This vulnerability is known to be exploited by threats that can eventually lead to substantial unacceptable risks that can undermine security principles or requirements such as confidentiality, integrity, and availability. Significant consequences of this risk are categorized into financial damages, legal implications, reputational damages, and regulatory implications to the cloud environment. As a result, a solution that could contribute to the remediation of these potential risks incurred due to the limitation of user identity and access control management was proposed and designed as User Behavior Trust-Based Adaptive Security framework. The design aims to enhance how cloud users' identity and access control might be managed effectively based on a user behavior trust context and adaptation of corresponding access control measures through adaptive security. The design capability was manifested by integrating it into the standard ISO/2705:2018 Risk Management process. Although, there have been several good information security frameworks such as ISO/IEC 27005:2018 and other technical countermeasures such as SaaS Identity & Access Management (IDaaS) to deal with this risk on the public cloud services. However, they are based on static mitigation approaches, so there is a solid need to shift towards a more dynamic strategical approach.

    The presented design work, User Behavior Trust-Based Adaptive Security framework, intends to serve as a proposed guideline for risk mitigation that would enhance user identity and access control limitations across the cloud. The solution functions by a trust modeling process that evaluates cloud user activities to compute a user behavior comprehensive trust degree. The resulting data is further used as input feeds parameters into a policy decision point process. The policy decision point process adapts the input parameters to user behavior trust level and behavior risk rating to determine the appropriate access control decision. Ultimately, the adaptive security solution consults the policy decision points to dynamically enforce the corresponding controls measures based on the access control decision received as input feed. The report also conducts a risk assessment process to identify vulnerabilities, threats, and risks related to user behavior trust level and risk rating regarding SaaS resources. Then adapt the mitigation solution, User Behavior Trust-Based Adaptive Security framework, as a possible risk treatment within the risk management process ISO/2705:2018.

    This report uses a design methodology derived from User Behavior Trust Modelling scientific research work, Gartner Adaptive Security Architecture Model, and eXtensible Access Control Markup Language's policy decision point concept. The design evaluates user behavior trust level by the trust modeling, while the integrated policy decision point processes the trust level to make the access control decision which is later enforced by the adaptive security solution. The report further adapts the risk management procedure ISO/2705:2018 to identify risk from user behavior and trust level, then implements the design solution as a possible risk treatment. The research findings were documented as Results and Discussion, where the functional and operational aspects of the designed framework were provided. In addition, the effects of applying the framework as a possible risk treatment solution were observed through conducting an ISO/2705:2018 risk management procedure. The notable outcome of a reduction of identified risk levels was an improvement in user attitude or behavior, which eventually increased user behavior trust level and reduced associated behavior risk. At the same time, the discussion detailed the interpretation of the results, implications, and limitation of the research, why the framework could be considered a remediation solution beyond the state-of-the-art for cloud user identity and access management—precisely by integrating user behavior, trust, policy decision making with adaptive security into risk management process to reduce IDM-associated risk in the SaaS.

    Finally, this study has outlined the significance of adopting the designed framework as a possible mitigation solution to enhance the shortcomings of user identity and access control management in the cloud. It has demonstrated that SaaS identified risk can be reduced to an acceptable level when user behavior and activities are taken seriously. Insight into the current trust state and associated risk level of cloud users are vital for continuous risk monitoring and reduction. The solution is to be used as a recommended guideline that might significantly contribute to the research community and information security field of cloud security. Future research direction to consider the possibility of simulating and transforming this conceptual and abstract framework into a real-world working solution due to research work limitations. The framework was designed based on recognized and accepted scientific and technological principles and concepts, from user behavior trust modeling, eXtensible access control markup language, and adaptive security architecture. In addition, to extend this concept to a future research area that will focus exclusively on application-processes behavior.

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  • 2.
    Andersson, Tommy
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Real-Time Inspired Hybrid Scheduler for 5G New Radio2022Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As an increasing position of the world’s communication moves towards the cloud and wireless solutions the requirement for good throughput and low delay increases. One step towards meeting higher requirements is the move from 4G Long Term Evolution (LTE) to 5G New Radio (NR). In order to utilize the potential of 5G NR, software needs to be improved. With the goal to lower the delay for delay critical applications and services when using 5G NR this thesis studies a new scheduler inspired by Earliest Deadline First (EDF) as a soft real-time system scheduler.

    This new scheduler called Real-Time Inspired Hybrid Scheduler (RTIHS) is proposed where two different schedulers are used depending on if the network traffic is delay critical or not. Delay critical traffic is served by the new Deadline Inspired Scheduler (DIS) scheduler and other traffic by a traditional Round Robin (RR) scheduler.

    The transmissions that are delay critical are prioritized differently with the use of a constant that has two functions. To determine if the transmission is in time or not, and how close the transmission is to the fixed deadline. Up until the deadline the priority of that transmission is increased with a factor that is affected by how close the current time is to the deadline. If the deadline has been missed the priority is, however, decreased with respect to how much it missed the deadline.RTIHS is implemented and tested in a state-of-the-art system simulator where services such as;Cloud Gaming (CG), Video on Demand (VoD), and web browsing are evaluated. An already existing technology named Low Latency Low Loss Scalable Throughput (L4S) is included in the evaluations to investigate how RTIHS scales. The performance of RTIHS is then compared to a Delay Scheduler(DS) and a RR scheduler that act as the baseline.

    The results show that RTIHS performs better for CG in terms of delay and nominal rate than the baseline, especially when the network is under high load. Using RTIHS compared to a DS shows an average increase of nominal rate by roughly 6 % and an average decrease of delay by 16 % for the average users. At the same time RTIHS does show higher delay and lower throughput for services such as VoD and web browsing, making its performance for those service worse than the baseline, especially when the network load is high. With the same comparison as before, RTIHS shows an average 17 % higher delay for web browsing and 1 % lower requested video rate than the DS for the average users. This is due to how the evaluated services are prioritized with the limited resources available. Since RTIHS prioritizes CG more, less resources remain for the other services. The baseline is not as biased towards CG and therefore has a lower nominal rate and higher delay for said service but better for the other services in comparison.

    Activating L4S mitigates the underwhelming performance of RTIHS for VoD and web browsing further improves the performance for CG. This is also true for the baseline which increases performance for CG and further increases the performance for other services with a small amount. With L4S activated the average increase of nominal rate in CG for RTIHS compared to the DS is 13 % for the average users and the average delay decrease is 9 %. Meanwhile the average requested video rate for RTIHS is less than 1 % lower than that of the DS for the average users and the delay for web browsing is 10 % higher than the DS for the average users.

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  • 3.
    Antoja Lleonart, Guillem
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    New Generation 4-Channel GNSS Receiver: Design, Production, and Testing2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Due to the current research needs and the lack of commercial multi-channel, multi-constellation GNSS receivers, a two-board solution has been developed so it can be mated with and take advantage of the processing power of the FPGA board branded as MicroZed.

    In order to achieve the proposed goals, an initial phase for assessing and updating the older design, building, and testing of SiGe modules (including both the electronics and casings) has been carried out. The results included demonstrate performances at logging GPS-L1 data with similar C/N0 and AGC values as the previous versions of the modules and offering navigation solutions with accuracies of a few meters. Secondly, a first iteration and design proposal for the new generation receiver has been proposed for GPS and GLONASS L1 and L2, which has been manufactured and tested. Partial tests have been performed due to the flaws of the current revision of the MicroZed Board in regards to its communication peripherals, and the results have validated the receiver’s design provided certain modifications are considered for future iterations. Furthermore, voltage and frequency tests have provided results with an error of less than 7%, and signal tests have provided C/N0 values similar to those of the SiGe modules of around 47[dB-Hz] which will be a useful baseline for future iterations. Finally, a design proposal for an Interface Board used between the older NT1065_PMOD Board and other FPGA boards carrying the standardized FMC connectors has been added to the report and negotiations with manufacturers have been engaged.

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  • 4.
    Arbi, Tarak
    et al.
    Department U2IS, ENSTA Paris Institut Polytechnique de Paris, France.
    Geller, Benoit
    Department U2IS, ENSTA Paris Institut Polytechnique de Paris, France.
    Ye, Zi
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Turbo Equalization for Underwater Communication Systems using Rotated Constellations2023In: OCEANS 2023 - Limerick, Institute of Electrical and Electronics Engineers Inc. , 2023Conference paper (Refereed)
  • 5.
    Ashraf, Asra
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Carlson, Johan E.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Hagström, Björn
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Ultrasound Communication Through Thin Plates: Understanding and Estimating the Channel2022In: 2022 IEEE International Ultrasonics Symposium (IUS), IEEE, 2022Conference paper (Refereed)
    Abstract [en]

    As with all digital communications, understanding the propagation channel is essential. In this paper we present an analytical model of a channel consisting of a thin plate, including effects of frequency-dependent speed of sound and attenuation. We show how a compressed sensing approach can be used to estimate this channel impulse response from real measurements, even for cases when the plate thickness causes the reverberating pulses to overlap. The estimate can be seen as a sparsity constrained deconvolution of the combined impulse responses of the transmitting and receiving transducers. We then show with simulations that the proposed sparsity-constrained estimate is able to cope also in the presence of dispersion. We also analyze the performance of the proposed method both with simulations and experiments on 6 mm and 2 mm thick glass plate and 3 mm thick aluminum plate, and our results show that the model assumptions seems to hold.

  • 6.
    Ashraf, Asra
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Carlson, Johan E.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Reinholdsen, Fredrik
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Enabling High-speed Ultrasound Communication Through Thin Plates by Reverberation Suppression2021In: 2021 IEEE International Ultrasonics Symposium (IUS), IEEE, 2021Conference paper (Refereed)
    Abstract [en]

    In all digital communications, knowledge of the propagation channel between the transmitter and the receiver is essential. For transmitting of data through solid bodies, such as metal plates, pipe walls, etc., ultrasound is a viable alternative to radio communication and wired transmission. In ultrasound communication, the channel consists of two parts, the combined response of the transducers used as transmitter and receiver, and the impulse response of the propagation medium itself. For a thin plate with parallel surfaces, this results in a reverberating channel that significantly reduces the achievable bitrate if not handled properly. In this paper we show with simulations how the bit-error rate in Orthogonal Frequency Division Multiplexing (OFDM) communications, is affected by the reverberating nature of the plate, and how this can be overcome by the introduction of a channel shortening filter placed in front of the OFDM conventional receiver. The results show that this significantly reduces the bit-error rate, especially for thin plates. If the reverberations instead were to be compensated by the conventional channel equalization method in OFDM, we show that for the example in the simulations, the bitrate would drop by almost 25 %, from about 3.9 Mbit/s to about 2.9 Mbit/s.

  • 7.
    Ashraf, Asra
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Carlson, Johan E.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    The solid-body reverberating ultrasound communications channel and its OFDM interference2022In: 2022 IEEE Latin-American Conference on Communications (LATINCOM) / [ed] Igor M. Moraes; Miguel Elias M. Campista; Yacine Ghamri-Doudane; Luís Henrique M. K. Costa; Marcelo G. Rubinstein, Institute of Electrical and Electronics Engineers (IEEE), 2022Conference paper (Refereed)
    Abstract [en]

    In this paper we present an analytical approach to the solid-state ultrasound communications channel.  Channel reverberations and the long associated channel delay spreads pose the possibility that the channel length exceeds that of the moderate cyclic prefix in an orthogonal frequency division multiplexing (OFDM) system, resulting in intersymbol and intercarrier interference.  We present a channel model based on the propagation material characteristics and evaluate the extent and impact of the intrinsic OFDM interferences. We derive an analytical expression and show with simulations that the intersymbol and intercarrier interference (ISI and ICI) are spectrally concentrated to the lower frequencies of the OFDM multiplex.

  • 8.
    Borg, Fredrik
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Increasing energy efficiency of O-RAN through utilization of xApps2023Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As 5G becomes more established and faces widespread roll-out, energy consumption of radio access networks around the globe will increase. Since the high-frequency radio waves used in 5G communication has a shorter effective range compared to the waves used in previous generations, 5G networks will require a higher number of radio units to compensate for their reduced range. Since the transmission of radio waves is a costly procedure in terms of energy consumption, this further increases the relevancy of radio equipment when considering solutions for increasing radio access networks' energy efficiency. This thesis has therefore provided a possible solution for increasing the energy efficiency of an O-RAN compliant radio access network by decreasing the energy consumption of its radio units. If a network's radio units are capable of entering a low-power sleep mode whenever they are left idle, i.e. not handling any traffic, the energy efficiency of a network can thus be increased by forcing its radio units to enter sleep mode as often as possible. This can be done by offloading traffic from radio units with little traffic onto other nearby radio units. The handovers required to perform such offloading, however, need to be predicted on the fly somewhere within the network. The solution proposed within this thesis therefore utilizes a component indigenous to the O-RAN architecture called RIC and its functionality-defining xApps which are capable of automatically detecting situations where radio units can be put to sleep as well as handling the offloading procedures. Through testing inside a simulated network, the set of xApps designed as a solution resulted in a potential 20-35% decrease in energy consumption among a radio access network's radio units.

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  • 9.
    Carlson, Johan
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Mohamad, Medhat
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Mbit/second Communication through a Rock Bolt Using Ultrasound2017Conference paper (Refereed)
    Abstract [en]

    In most industrial processes transfer of data and software from or to sensors is an essential part of the monitoring and control systems. Many of the older, wired communication systems have been or are being replaced with wireless alternatives. A number of challenges are associated with this replacement: Radio receivers are subject to interference from other radio sources. Similarly, radio transmitters may cause undesired interference into other equipment and environments. Compared to wired solutions, security becomes an issue as radio communication links are more vulnerable to eavesdropping than wired schemes. Radio communication with sensors and sensor platforms embedded deep inside large metal structures or fluid tanks may be difficult or even impossible. The objective of this work is to develop and evaluate a high data-rate communications scheme based on ultrasound, which can be used to transmit wirelessly through solid structures. An example will be given using a one-meter segment of a rock bolt.

  • 10.
    Carlson, Johan
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Mohamad, Medhat
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Mbit/second Communication through a Rock Bolt Using Ultrasound2017In: IEEE International Ultrasonics Symposium, IUS, Piscataway, NJ: IEEE Computer Society, 2017, article id 8092474Conference paper (Refereed)
    Abstract [en]

    This paper presents a digital communication system based on Orthogonal Frequency Division Multiplexing (OFDM) and MHz-range ultrasound, for transmission of data through solid materials and liquids. The system is tested on experiments using a off-the-shelf ultrasound transducers with a center frequency of 3.5 MHz as transmitter and receiver, respectively. The propagation medium in the experiment was a 1 m long section of an epoxy coated steel rock bolt. The results show that data rates in excess of 1 Mbit/second is attainable, using readily available hardware and software.

  • 11.
    de Leon, Miguel Ponce
    et al.
    TSSG, Waterford Institute of Technology, Waterford, Ireland.
    Eriksson, Mats
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Distance- Spanning Technology.
    Balasubramaniam, Sasitharan
    TSSG, Waterford Institute of Technology, Waterford, Ireland.
    Donnelly, Willie
    TSSG, Waterford Institute of Technology, Waterford, Ireland.
    Creating a distributed mobile networking testbed environment - through the Living Labs approach2006In: TridentCom 2006: Proceedings of the second International Conference on Testbeds and Research Infrastructures for the Development of Networks and Communities : Barcelona, Spain, March 1-3, 2006., Piscataway, NJ: IEEE Communications Society, 2006, p. 139-143Conference paper (Refereed)
    Abstract [en]

    Today, new ways of constructing and delivering complex wireless and mobile services require more elaborate and distributed prototyping, testing, and validation facilities. Testbeds are becoming an important tool for integrating technology components into the complex environment of the wireless world and end-users in their daily life. However technology in itself is no longer valid-benefits and usefulness for people in their daily life must be proven before the technology or service can be said to be a success.

    Living Labs is a user-centred real-life approach to wireless and mobility service and technology design and development (as well as other service areas). The user-centred approach places special emphasis on the need to develop mobile services that are usable, i.e. effective, efficient and satisfying to use, and has full end user integration in the creation and validation processes, which is necessary for gauging market acceptance of the developed prototypes and solutions.

  • 12.
    Doria, Avri
    et al.
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    Hellstrand, Fiffi
    Sundell, Kenneth
    Worster, Thomas
    General switch management protocol (GSMP) V32002Report (Other academic)
    Abstract [en]

    This document describes the General Switch Management Protocol Version 3 (GSMPv3). The GSMPv3 is an asymmetric protocol that allows one or more external switch controllers to establish and maintain the state of a label switch such as, an ATM, frame relay or MPLS switch. The GSMPv3 allows control of both unicast and multicast switch connection state as well as control of switch system resources and QoS features.

  • 13.
    Eriksson, Oscar
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Jämförelse av tjänstefördelare (CPE:er)2023Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    This report is based on a final project carried out at Skellefteå Kraft Fibernät. The aim was to compare a number of different models of CPE's and find an alternative CPE to the one currently used today. In order to compare the devices, a number of tests were carried out such as a throughput-test, multicast-test and a evaluation of the ease of installation. It was made some interesting discoveries such as that a firmware upgrade improved throughput and that only one CPE had layer 3 functionality. In the discussion, a recommendation on CPE is finally made based on the results in the report.

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  • 14.
    Giri, Manav
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Rönnberg, Sarah K
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bollen, Math H. J.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Observed Harmonic Levels on the Low Voltage Grid during EV DC Fast Charging2022In: 2022 20th International Conference on Harmonics & Quality of Power (ICHQP) Proceedings: “Power Quality in the Energy Transition”, IEEE, 2022Conference paper (Refereed)
    Abstract [en]

    The paper contains a set of observations on the fast charging of electric vehicles (EV’s) on Swedish low voltage networks in rural/commercial and urban areas. The emphasis of the study has been to analyze the impact of EV charging on the electric grid and particularly on the observed waveform distortion. The paper focuses on the observation of harmonics on the grid and the variation in the observed harmonics with time as the charging current increases from a small value associated with limiting the inrush current, to the value required by the EV’s for the fast charging of the battery pack. Observations from a bus charging station at Gothenburg are also discussed.

  • 15.
    Halén, Axel
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Cloud Monitoring and observation measurements in OpenStack environment2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
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  • 16.
    Ibrahim, Emad Farouk
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Selected Topics on Reconfigurable Intelligent Surfaces2022Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Reconfigurable intelligent surface (RIS) is a promising technology for wireless communications applications. A RIS is a thin planar array that consists of multiple reflecting elements, each of which is connected to a tunable chip and can induce a controllable reflection coefficient to the incident signal. The RIS is a nearly passive unit as it only leverages the reflection on its elements and it does not consume any power for transmission. Furthermore, RISs can actively control the propagation channel, by accurately tuning the reflection coefficients of their elements to fit a specific need. The advantage of the RIS arises in creating energy-efficient smart radio environments wherein the wireless channel becomes an optimization variable. In this thesis, we study some of the potential applications and deployments for the RIS in wireless communications. First, the multiple-input multiple-output channel matrix in line-of-sight (LoS) environments turns out to be rank deficient such that spatial multiplexing becomes unattainable. Thus, we exploit the RISs to create additional degrees of freedom by synthesizing a sort of multi-path propagation. Then, we optimize the transmit covariance matrix and the reflection coefficients of the RISs using an alternating optimization algorithm to maximize the achievable rate. Alternatively, we propose different schemes to enhance the composite channel power which would result in an improvement to the achievable rate. Second, we characterize the efficient regions of RIS deployments with single and multiple antenna systems in Rician fading channels. We show that in RIS-aided single antenna systems, near RIS deployments relative to the transmitter or receiver are always better than far deployments. Moreover, we show that in RIS-aided multiple antenna systems, the efficient regions of operations are highly dependent on the propagation environment itself. In LoS environments, both the near and far deployments can result in substantial achievable rate gains. However, as the channel becomes richer with multipath, near deployments gradually become more efficient than the far deployments. Third, we propose the RIS to act as an access point for information transfer by exploiting the polarization control ability of the RIS. In particular, the RIS alternates the polarization state of the reflected waves to perform conventional as well as differential polarization shift keying (PolSK) modulation schemes. In RIS-aided conventional PolSK, two different schemes are proposed. In the first scheme, the receiver corrects for the polarization mismatch loss that occurs in the wireless channel. In the second scheme, the RIS additionally pre-codes the reflected wave to compensate for the polarization mismatch. In RIS-aided differential PolSK, the detection process is independent of the polarization mismatch. Thus, there is no need for a polarization mismatch compensation process by either the receiver or the RIS.

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  • 17.
    Ibrahim, Emad Farouk
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Nilsson, Rickard
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Binary Polarization Shift Keying with Reconfigurable Intelligent Surfaces2022In: IEEE Wireless Communications Letters, ISSN 2162-2337, E-ISSN 2162-2345, Vol. 11, no 5, p. 908-912Article in journal (Refereed)
    Abstract [en]

    We propose a novel binary polarization shift keying modulation scheme for a line-of-sight environment by exploiting the polarization control ability of the reconfigurable intelligent surface (RIS). The RIS encodes the information data in terms of the polarization states of either the reflected wave from the RIS or the composite wireless channel between an RF source and receiver. In the first case, polarization mismatch correction becomes essential at the receiver. In the second case, the RIS pre-codes the reflected wave to compensate for the polarization mismatch which allows non-coherent demodulation at the receiver.

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  • 18.
    Ibrahim, Emad Farouk
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Nilsson, Rickard
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Differential Polarization Shift Keying Through Reconfigurable Intelligent Surfaces2022In: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558Article in journal (Other academic)
    Abstract [en]

    We propose a novel reconfigurable intelligent surface (RIS)-aided differential polarization shift keying modulation scheme for a line-of-sight environment. In this scheme, the RIS exploits the state of polarization (SoP) of the reflected waves over two successive reflection frames to encode the data bit. In particular, the RIS either preserves the SoP of the reflected wave similar to the previous reflection frame or switches it to another orthogonal SoP as a function of the information data bits. The proposed scheme allows non-coherent data detection without the need for polarization mismatch estimation and compensation processes at the receiver.    

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  • 19.
    Ibrahim, Emad
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Nilsson, Rickard
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Intelligent Reflecting Surfaces for MIMO Communications in LoS Environments2021In: 2021 IEEE Wireless Communications and Networking Conference (WCNC), IEEE, 2021Conference paper (Refereed)
    Abstract [en]

    In line-of-sight (LoS) environments, point-to-point (P2P) multiple-input multiple-output (MIMO) channel matrix turns out to be rank deficient such that spatial multiplexing becomes unattainable. In this paper, we propose the deployment of distributed intelligent reflecting surfaces (IRSs) to act as artificial scatterers and synthesize a sort of multi-path propagation such that additional degrees of freedom are created. We show that given the far-field deployment of the IRS, it simply resembles a full-duplex relay with a single effective reflection coefficient. However, to maximize the channel capacity both the effective reflection coefficients of all IRSs and the transmit covariance matrix should be jointly optimized, which is a nonconvex optimization problem. Thus, we develop an alternating optimization algorithm to iteratively find a sub-optimal solution. Moreover, we propose different schemes to enhance the composite channel power which would result in an improvement to the achievable rate. Our simulation results show that the deployment of distributed IRSs with P2P MIMO systems in LoS environments increases the rank of the channel matrix, and improves the achievable rate by making spatial multiplexing possible.

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  • 20.
    Isaksson, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Visning av internt genererad information med hjälp av Raspberry Pi2023Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
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  • 21.
    Jasim, Al-Hussein Hameed
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Blixt™: An Available Bandwidth Measurements’ Approach for High-Speed Mobile Networks2018Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    Mobile networks are in the process of becoming the world’s leading medium for data traffic. This challenge has raised the bar for Quality of Services (QoS) provided by the mobile network operators. It requires methods and tools to verify the Service Level Agreement (SLA) and benchmark competitors by comparing metrics of QoS, e.g. the round-trip time and available bandwidth. For this purpose, Blixt™ has been developed, which is a property of InfoVista Sweden AB. Blixt™ is an Android application which measures the available bandwidth and the round-trip time for the latest generation of mobile networks. Blixt™ approach relies on a time-stamping protocol commonly known as Two-Way Active Measurement Protocol (TWAMP). This research work discusses how the packet probing parameters affect the accuracy of measurements and the level of intrusiveness. The performance of the technique was experimentally tested and compared to other tools and methods, namely, iPerf3, nPerf and FTP test.

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  • 22.
    Krasheninnikov, Pavel V.
    et al.
    Siberian State University of Telecommunications and Information Sciences, Novosibirsk, Russia.
    Melent’ev, Oleg G.
    Siberian State University of Telecommunications and Information Sciences, Novosibirsk, Russia.
    Kleyko, Denis
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Shapin, Alexey
    Ericsson Research, Luleå, Sweden.
    Parameter Estimation for the Resulting Logical Channel Formed by Minimizing Channel Switching2019In: Automation and remote control, ISSN 0005-1179, E-ISSN 1608-3032, Vol. 80, no 2, p. 278-285Article in journal (Refereed)
    Abstract [en]

    We propose a method for calculating the parameters of the resulting discrete channel for secondary users in cognitive radio systems formed by the algorithm for minimizing channel switchings. The availability of channel slots is defined by a simple Markov chain. We obtain mathematical expressions for determining the transition probabilities of a graph reduced to two states for any number of primary channels.

  • 23.
    Krutrök, Wilma
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    QoE Indication Feedback used for Resource Allocation in 5G2022Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
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  • 24.
    Lau, Steven
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Analys och mätning av WLAN på äldreboende2022Independent thesis Basic level (university diploma), 80 credits / 120 HE creditsStudent thesis
    Abstract [sv]

    CGI har ett projekt från Skellefteå kommun där de ska mäta trådlösa nätverk hos olika siter för att försöka identifiera problem med frånkoppling från trådlösa nätverket samt tillföra förbättringar. 

    Mitt uppdrag blev att göra en site survey på trådlösa nätverket hos äldreboende sedan en analys och predictive survey samt förbättringsförslag. Verktyget jag har använt är ekahau PRO och ekahau survey. Platsen jag har mät är Björkhammargården i Jörn. Innan mätningen behövs en rätt skalad planritning vilket jag gjorde på adobe acrobat och ekahau programmet. Det trådlösa nätverket hos äldreboende var mestadels god, täckningen, signalstyrka och trådlösa nätverket var generellt god men en del av området var mindre lämplig och behöver en förbättring, två nya accesspunkter ska installeras. Efter site survey har en predictive survey gjorts, där har jag ritat upp väggar, satt ut accesspunkter för att få god täckning och signalstyrka, kanalplanering och hur transmit power control fungerar.

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  • 25.
    Lorentzson, Gabriel
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Performance and optimization of mobility between terrestrial networks and non-terrestrial networks2022Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The 3rd generation partnership program (3GPP) has in recent years started working on integratingnon-terrestrial networks (NTN) into the 5G eco-system. This thesis focuses on the mobility between NTN and TN, which is of great importance if 5G NTN is to provide seamless and limitless connectivity. The target of this thesis is to understand and improve the mobility performance ofnon-terrestrial and terrestrial networks in a heterogeneous scenario. We first analyze data from system-level simulations of rural deployment scenarios when altering the parameters of the A3 measurement event and and then we further evaluate the use of a new NTN-specific distance-based measurement event, the D1 measurement event. We also evaluate the impact of needing toperform GNSS measurements when performing handovers from a terrestrial to a non-terrestrialnetwork.

    The results show that acquiring GNSS data during the handover procedure significantly increases handover delay time but does not heavily impact overall network performance. Additionally, the results show that by changing the parameters of the A3 measurement event and using the D1measurement event, ping-pong events between NTN-TN and unnecessary handovers to NTN canbe significantly reduced and improve the overall network performance. 

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  • 26.
    Lundberg, Simon
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Load Distribution in the Open Radio Access Network2023Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As 5G and O-RAN become more widely used, the number of user equipment requesting access to the network will increase. This will require operators to expand their 5G solutions by purchasing more hardware to handle the increase in demand. The acquisition of new hardware will have both an economic and an environmental impact. Hardware is costly for operators, both in initial cost and when operating it. There is also a significant energy cost associated, which has a negative environmental impact.

        This thesis explores the benefits of more advanced control over the path taken within the Radio Access Network, with the goal of increasing the number of user equipment able to connect to a static set of hardware. The control comes from new algorithms designed with the intuition that providing connections with only the bare essentials and nothing more would, in theory, increase the capacity of the whole network. Three algorithms were tested, with one representing a basic control method of selecting the first valid connection, and the other two were built on the intuition of the worst acceptable connection.

        The three algorithms were tested on four different shapes of network configuration at four different sizes. The tests were run on a graph data structure implemented in C++ that represents the logical paths a connection could take. This resulted in a noticeable improvement in networks that exhibited a triangular structure, with more units as one moved toward the edge of the network. The largest improvement observed managed to fit 18.9% more units into the network.

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  • 27.
    Lyamin, Nikita
    et al.
    Halmstad University, Sweden.
    Kleyko, Denis
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Delooz, Quentin
    University of Liège, Belgium.
    Vinel, Alexey
    Halmstad University, Sweden.
    AI-Based Malicious Network Traffic Detection in VANETs2018In: IEEE Network, ISSN 0890-8044, E-ISSN 1558-156X, Vol. 32, no 6, p. 15-21Article in journal (Refereed)
    Abstract [en]

    Inherent unreliability of wireless communications may have crucial consequences when safety-critical C-ITS applications enabled by VANETs are concerned. Although natural sources of packet losses in VANETs such as network traffic congestion are handled by decentralized congestion control (DCC), losses caused by malicious interference need to be controlled too. For example, jamming DoS attacks on CAMs may endanger vehicular safety, and first and foremost are to be detected in real time. Our first goal is to discuss key literature on jamming modeling in VANETs and revisit some existing detection methods. Our second goal is to present and evaluate our own recent results on how to address the real-time jamming detection problem in V2X safety-critical scenarios with the use of AI. We conclude that our hybrid jamming detector, which combines statistical network traffic analysis with data mining methods, allows the achievement of acceptable performance even when random jitter accompanies the generation of CAMs, which complicates the analysis of the reasons for their losses in VANETs. The use case of the study is a challenging platooning C-ITS application, where V2X-enabled vehicles move together at highway speeds with short inter-vehicle gaps.

  • 28.
    Marchner Brandt, Joar
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Effects of water-vapor on the Ka/Q band Earth-space radio propagation channel2021Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A higher frequency radio channel both increase the possible data rate and de- crease the required antenna size to efficiently transmit data. Higher frequency also introduce larger weakness to signal loss due to atmospheric effects. Al- phasat satellite conduct experiments for future use of higher frequencies by the Aldo Paraboni Payload. Budapest University of Technology have receiv- ing antennas for both transmitted Alphasat signals in the Ka band and Q band. Meteorological surface data is also gathered in close proximity of the receiving antennas. The relationship between the meteorological data and attenuation on the received signal is studied. A focus lies on the effects of water vapor and clouds. 

    International Telecommunication Union prediction methods for clouds and atmospheric gases are applied on the meteorological data. This provide a foundation for the analysis of received attenuation on the Q band signal at frequency 39,402 GHz. The analysis aim to investigate if there is any rela- tionship between surface meteorological data and atmospheric effects such as cloud and atmospheric gases. Cross-correlation was used to find similarities between the parameters. 

    The analysed data is over the month of April 2018. During this month seven different rain events were indicated by the rain rate tipping bucket. These regions showed strong influence of rain on the surface temperature and hu- midity was used to identify other regions with no rain characteristics. Only four out of 16 regions above 2,5 dB had no characteristics similar to rain with four other regions showing indistinguishable source. These eight regions were most promising of being caused by cloud and atmospheric gases. The large quantity of attenuation events below 2,5 dB made further manual analysis difficult. ITU methods predicted a maximum attenuation of 3 dB for clouds and atmospheric gases. Future work could improve analysis on attenuation events below 2,5 dB by pattern recognition with the characteristics found in this work. 

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  • 29.
    Marques Lima, Francisco Rafael
    et al.
    Federal University of Ceará.
    Maciel, Tarcisio
    Federal University of Ceará.
    da Cruz Freitas Junior, Walter
    Federal University of Ceará.
    Porto Cavalcanti, Francisco Rodrigo
    Federal University of Ceará.
    Bezerra, Nibia Souza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    B. Rodrigues, Emanuel
    Federal University of Ceará.
    Method and apparatus for resource allocation satisfying multiple performance constraints2013Patent (Other (popular science, discussion, etc.))
  • 30.
    Nilsson, Daniel
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Evaluation of Secure Long Distance Communication in Non-Urban Environments2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
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  • 31.
    Nsabimana, Aimable
    et al.
    Department of Agricultural Economics and Rural Development, University of Rwanda, Kigali, Rwanda.
    Amuakwa-Mensah, Franklin
    Department of Economics, Swedish University of Agricultural Sciences (SLU), Box 7013, 750 07, Uppsala, Sweden.
    Does mobile phone technology reduce agricultural price distortions? Evidence from cocoa and coffee industries2018In: Agricultural and Food Economics, E-ISSN 2193-7532, Vol. 6, no 1, article id 20Article in journal (Refereed)
    Abstract [en]

    Agricultural price distortion which is the discrepancy between world market price of agricultural produce and price received by farmers as a result of market interventions by governments, either through subsidies or taxes or even trade protection systems, has received rare attention in the cocoa and coffee sub-sectors. This study examines the contribution of mobile phone technology in reducing price distortions in cocoa and coffee production. In addition, we tested stylized facts such as the development paradox, resource abundance, and group-size effect in agricultural price distortions literature. The findings suggest that access to mobile phones reduces the extent of price distortions. The effect of mobile phone usage on the extent of price distortion, the nominal rate of assistance, and relative price margin is conditional on internet connectivity. Whereas our results support the development paradox and group-size effect hypotheses, the resource abundance hypothesis is not supported. Based on our results, policies that seek to reduce the cost of telecommunication, increase competition in the telecommunication industry, and increase economic growth would go a long way to reduce price distortion in the cocoa and coffee industries.

  • 32.
    Olsson, Robert
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    An intelligent gateway for LoRaWAN coverage extension2020Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    LoRaWAN is one of the most adopted low-power wide-area networks, which use theproprietary LoRa modulation developed by Semtech to provide high sensitivity at lowdata rates for long ranges. LoRaWAN providing coverage using single-hop gatewaysto thousands of end-devices (sensors) running on batteries. Each gateway requires aconnection to the internet or a private network (Ethernet, 3G/4G, Wifi) to communicatewith the network server. In obstructed areas, with mountains, foliage, or simplyvast areas, multiple gateways are required to provide coverage for the end-devices.Internet/mobile coverage might be missing in some areas. Which quickly brings upthe cost of internet connection in these areas, unless a solution is developed that routesmessages between the gateways using the existing LoRa radio communication standard.Thus reducing required internet connections while providing coverage. This solutionwas developed and evaluated, with a focus on supporting LoRaWAN deviceswith bidirectional capabilities, following the regional regulations, and providing arouting protocol that minimizes the extra data that comes with routing messages overa network. Experiments of three gateways showed that the solution provides a functioningrouting protocol, with as low as 3 extra bytes for routing. While fast enough toprovide bidirectional communication support for end-devices located farthest awayfrom the gateway with the server connection.

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  • 33.
    Palm, Jonathan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Optimization of 5G New Radio for Fixed Wireless Access2019Independent thesis Advanced level (professional degree), 300 HE creditsStudent thesis
    Abstract [en]

    With the advent of new 5G networks, the interest in connecting house-hold to the Internet via mobile networks has increased. One such way toconnect users is using completely stationary antennas. This use-case iscalled Fixed Wireless Access (FWA) and is seen as promising, cost-efficient means of expanding internet connectivity. Stationary users connected at high frequencies, such as 28 GHz, leads to a special use-case and environment for 5G New Radio (NR). This thesis investigates the characteristics of these FWA deployments and the control signaling on the physical layer of NR. The overhead and feasibility of eachsignal is considered. A FWA deployment in the 28 GHz band with 64 users is simulated with different line-of-sight settings and receiver placements. It is concluded that direct line-of-sight to the base station is vital for high user and cell throughput and that there are significant drawbacks of placing the receiver indoors. New algorithms for Channel State Information Reference Signal (CSI-RS) transmission for both beam management and link adaptation are proposed and evaluated. The beam management algorithms do not displayany significant performance gains over the default sweeping algorithm. Closer investigation of simulation results shows that several beams can have almost equal signal strength with the chosen antenna set up, minimizing potential gains of quickly adapting to environmental changes. Results show there are clear benefits of using an aperiodic and adaptive transmission scheme for CSI-RS transmissions over a fixed-rate transmission scheme, yielding a 7% increase in user goodput at similar levels of overhead.

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  • 34.
    Perdomo, José
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    UE Performance in a 5G Multi-connectivity UDN City Scenario2019Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    Multi-connectivity and network densification are two solutions intended to enhance user throughput and reliability. These solutions are critical since 5G NR uses a wide range of frequency bands, which exhibit different varying radio coverage characteristics. This work studies the user equipment (UE) performance using multi-connectivity within an ultra-dense network (UDN) deployed in an urban city environment. By being connected to more than one access node simultaneously, the UE should benefit from increased reliability and data rates at the expense of a potentially increased power consumption. In this letter, we have constructed an urban city environment and a context-aware UE power consumption model. The performance of the UE is assessed with an uplink power control scheme for multi-connectivity and a novel multi-connectivity scheme is proposed. Our simulation results show that dual-connectivity increases performance by up to 44% and 27% in average downlink and uplink throughput, respectively. Similarly, tri-connectivity does the same by up to 45% and 25%. At mid load (forty-five users), the average increase in UE power consumption compared to single-connectivity is 25% and 60% for dual-connectivity and tri-connectivity, respectively. Dual-connectivity increases global UE energy efficiency by up to 30%. Within an urban environment, dual-connectivity decreases the RLF rate by 20% compared to single-connectivity for high speed users.

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  • 35.
    Petersson Steenari, Kim
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    A neuromorphic approach for edge use allocation2022Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This paper introduces a new way of solving an edge user allocation problem. The problem is to be solved with a network of spiking neurons. This network should quickly and with low energy cost solve the optimization problem of allocating users to servers and minimizing the amount of servers hired to reduce the related hiring cost. The demonstrated method is a simulation of a method which could be implemented onto neuromorphic hardware. It is written in Python using the Brian2 spiking neural network simulator. The core of the method involves simulating an energy function through the use of circuit motifs. The dynamics of these circuit motifs mimic a search for the lowest energy point in an energy landscape, corresponding to a valid solution for the edge user allocation problem. The paper also shows the results of testing this network within the Brian2 environment. 

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  • 36.
    Pinoé Chacón, Luis
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    IEEE 802.11nImplementering och Analys: Accesspunkter2014Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    Abstract

    This thesis has been performed at the company Axe'L Data Service. My assignment was to implement a wireless network for the company GUNSHILL ​​AB.

    GUNSHILL ​​AB, works with milk- and meat production, and use a robotic milking system called Lely. This system is controlled through application software installed on Android or iPhone platforms, specifically mobile phones. The wireless network implemented at GUNSHILL AB, has about tree hundred fifty square meter Wi-Fi coverage.

    In addition to the wireless system, we deployed a monitoring system as a tool for measuring performance of the access points and monitoring them.

    This thesis summarizes and goes through the entire process of the wireless- and monitoring system deployment, and performs analysis of the IEEE 802.11n technology based on the technology primarily in Ubiquiti features for 802.11n devices.

    The conclusion of this thesis is that the project meets the requirements of GUNSHILL ​​AB as expected. The implemented wireless network system covers three hundred fifty square meters and delivers a wireless Internet connection with a speed of 6.4 Mbit/s, which resembles, approximately 90.6 % of the initial speed provided by the ISP (7 Mbit/s).

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  • 37.
    Pinto, Rui
    et al.
    Department of Informatics Engineering, Faculty of Engineering, University of Porto, Porto, Portugal.
    Gonçalves, Gil
    Department of Informatics Engineering, Faculty of Engineering, University of Porto, Porto, Portugal.
    Delsing, Jerker
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Embedded Internet Systems Lab.
    Tovar, Eduardo
    Research Centre in Real-Time and Embedded Computing Systems, Polytechnic of Porto - School of Engineering, Porto, Portugal.
    Enabling data-driven anomaly detection by design in cyber-physical production systems2022In: Cybersecurity, E-ISSN 2523-3246, Vol. 5, article id 9Article in journal (Refereed)
    Abstract [en]

    Designing and developing distributed cyber-physical production systems (CPPS) is a time-consuming, complex, and error-prone process. These systems are typically heterogeneous, i.e., they consist of multiple components implemented with different languages and development tools. One of the main problems nowadays in CPPS implementation is enabling security mechanisms by design while reducing the complexity and increasing the system’s maintainability. Adopting the IEC 61499 standard is an excellent approach to tackle these challenges by enabling the design, deployment, and management of CPPS in a model-based engineering methodology. We propose a method for CPPS design based on the IEC 61499 standard. The method allows designers to embed a bio-inspired anomaly-based host intrusion detection system (A-HIDS) in Edge devices. This A-HIDS is based on the incremental Dendritic Cell Algorithm (iDCA) and can analyze OPC UA network data exchanged between the Edge devices and detect attacks that target the CPPS’ Edge layer. This study’s findings have practical implications on the industrial security community by making novel contributions to the intrusion detection problem in CPPS considering immune-inspired solutions, and cost-effective security by design system implementation. According to the experimental data, the proposed solution can dramatically reduce design and code complexity while improving application maintainability and successfully detecting network attacks without negatively impacting the performance of the CPPS Edge devices.

  • 38.
    Poirot, Valentin
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Energy-Efficient Multi-Connectivity for Ultra-Dense Networks2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In 5G systems, two radio air interfaces, evolved LTE and New Radio (NR), will coexist. By using millimeter waves, NR will provide high throughputs, but the higher frequencies will also lead to increased losses and a worse coverage. Multi-connectivity is therefore envisioned as a way to tackle these effects by connecting to multiple base stations simultaneously, allowing users to benefit from both air interfaces’ advantages. In this thesis, we investigate how multi-connectivity can be used efficiently in ultra-dense networks, a new paradigm in which the number of access nodes exceeds the number of users within the network. A framework for secondary cell association is presented and an energy efficiency’s condition is proposed. Upper and lower bounds of the network’s energy efficiency are analytically expressed. Algorithms for secondary cell selection are designed and evaluated through simulations. Multi-connectivity showed an improvement of up to 50% in reliability and and an increase of up to 20% in energy efficiency.

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  • 39.
    Raghavendran, Krishnaraj
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Analysis Of Fastlane For Digitalization Through Low-Code ML Platforms2022Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Even a professional photographer sometimes uses automatic default settings that come up with the camera to take a photo. One can debate the quality of outcome from manual vs automatic mode. Until and unless we have a professional level of competence in taking a photo, updating our skills/knowledge as per the latest market trends and having enough time to try out different settings manually, it is worthwhile to use Auto-mode. As camera manufacturers, after several iterations of testing, comes up with the list of ideal parameter values, which is embedded as a factory default setting when we choose auto-mode. For non-professional photographers or amateurs recommend using the auto-mode that comes with the camera for not missing the moment. Similarly, in the context of developing machine learning models, until and unless we have the required data-engineering and ML development competence, time to train and test different ML models and tune different hyper parameter settings, it is worth to try out to Automatic Machine learning feature provided out-of-shelf by all the Cloud-based and Cloud-agnostic ML platforms. This thesis deep dives into evaluating possibility of generating automatic machine learning models with no-code/low-code experience provided by GCP, AWS, Azure and Databricks. We have made a comparison between different ML platforms on generating automatic ML model and presenting the results. It also covers the lessons learnt by developing automatic ML models from a sample dataset across all four ML platforms. Later, we have outlined machine learning subject matter expert’s viewpoints about using Automatic Machine learning models. From this research, we found automatic machine learning can come handy for many off-the-shelf analytical use-cases, this can be highly beneficial especially for time-constrained projects, when resource competence or staffing is a bottleneck and even when competent data scientists want a second-opinion or compare AutoML results with the custom ML model built. 

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  • 40.
    Raheem, Muiz Olalekan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Rogue Drone Detection2023Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Rogue drones have become a significant concern in recent years due to their potential to cause harm to people and property and disrupt critical infrastructure and public safety. As a result, there has been a growing need for effective methods to detect and mitigate the risks posed by these drones. The proposed study aims to address the task by using a Radio Frequency (RF) based approach. Also, ensemble Machine Learning (ML) methods, as well as Deep Learning (DL) techniques were utilized as classification algorithms. Three levels of classification were defined for the task which includes drone detection, identification, and characterization based on operation mode. For the three levels, Deep-Complex Convolutional Neural Network performed the best and achieved an average accuracy of 99.82%, 94.20%, and 90.25%, respectively. 

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  • 41.
    Reinholdsen, Fredrik
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    A Blind Constellation Agnostic VAE Channel Equalizer and Non Data-Assisted Synchronization2021Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    High performance and high bandwidth wireless digital communication underlies much of modern society. Due to its high value to society, new and improved digital communication technologies, allowing even higher speeds, better coverage, and lower latency are constantly being developed. The field of Machine Learning has exploded in recent years, showing incredible promise and performance at many tasks in a wide variety of fields. Channel Equalization and synchronization are critical parts of any wireless communication system, to ensure coherence between the transmitter and receiver, and to compensate for the often severe channel conditions. This study mainly explores the use of a Variational Autoencoder (VAE) architecture, presented in a previous study, for blind channel equalization without access to pilot symbols or ground-truth data. This thesis also presents a new, non data-assisted method of carrier frequency synchronization based around the k-means clustering algorithm. The main addition of this thesis however is a constellation agnostic implementation of the reference VAE architecture, for equalization of all rectangular QAM constellations. The approach significantly outperforms the traditional blind adaptive Constant Modulus algorithm (CMA) on all tested constellations and signal to noise ratios (SNRs), nearly equaling the performance of a non-blind Least Mean Squares (LMS) based Decision Feedback Equalizer (DFE).

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  • 42.
    Shapin, Alexey G.
    et al.
    Ericsson Research, Luleå, Sweden.
    Kleyko, Denis V.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Krasheninnikov, Pavel V.
    SibSUTIS, Novosibirsk, Russia .
    Melentyev, Oleg G.
    SibSUTIS, Novosibirsk, Russia.
    An Algorithm for the Exact Packet Error Probability Calculation for Viterbi Decoding2018In: 2018 14th International Scientific Technical Conference on Actual Problems of Electronic Instrument Engineering (APEIE – 2018) – Proceedings: [Труды XIV международной научнотехнической конференцииактуальные проблемыэлектронного приборостроения (АПЭП – 2018)], IEEE, 2018, p. 282-287Conference paper (Refereed)
    Abstract [en]

    The performance of the Viterbi decoding algorithm in a binary symmetric channel is usually estimated by a lower or an upper bounds of a bit error probability. Nowadays, there are expressions for the exact bit error probability estimation for several trivial convolutional codes. However, traffic in modern systems is packetized. Thus, packet error probability is also an important performance metric. Besides, the existed methods could not be used for the task of packet error probability estimation. Therefore this paper presents an algorithm for the calculation of the exact packet error probability for the Viterbi decoding. The algorithm is based on a recurrent search of the cases, which lead to an error free-decoding and then cumulative probabilities of these cases are calculated.

  • 43.
    Sitepu, Feter Akira Vedaalana
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Performance Evaluation of Various QUIC Implementations: Performance and Sustainability of QUIC Implementations on the Cloud2022Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    QUIC is a new secure multiplexed transport protocol built on top of UDP. This general-purpose transport protocol aims to provide the lowest connection latency possible and solve the shortcomings of TCP, UDP, and current problems of the internet. Furthermore, it allows further development of the transport protocol without upgrading the network infrastructure. Last year in May 2021, QUIC was finally standardized by the IETF, allowing for full development and release while also opening the path for future research as older research dated due to using the older version and the finalization of QUIC standard protocol. While there are a lot of different QUIC implementations, this thesis selected two and conducted a performance evaluation on the cloud environment and compared the two while also taking the sustainability aspect into account. Asa result, we will find which of the selected implementation is environmentally friendly through this experiment while also providing good performance.

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  • 44.
    Stöggl, Thomas
    et al.
    Mittuniversitetet, Avdelningen för hälsovetenskap.
    Holst, Anders
    School of Computer Science and Communication, Royal Institute of Technology, Stockholm, Sweden .
    Jonasson, Arndt
    Swedish Institute of Computer Science, Kista, Sweden.
    Andersson, Erik
    Mittuniversitetet, Avdelningen för hälsovetenskap.
    Wunsch, Thomas
    Department of Sport Science and Kinesiology, University of SalzburgHallein/Rif, Austria .
    Norström, Christer
    Swedish Institute of Computer Science, Kista, Sweden .
    Holmberg, Hans-Christer
    Mittuniversitetet, Avdelningen för hälsovetenskap.
    Automatic classification of the sub-techniques (gears) used in cross-country ski skating employing a mobile phone2014In: Sensors, E-ISSN 1424-8220, Vol. 14, no 11, p. 20589-20601Article in journal (Refereed)
    Abstract [en]

    The purpose of the current study was to develop and validate an automatic algorithm for classification of cross-country (XC) ski-skating gears (G) using Smartphone accelerometer data. Eleven XC skiers (seven men, four women) with regional-to-international levels of performance carried out roller skiing trials on a treadmill using fixed gears (G2left, G2right, G3, G4left, G4right) and a 950-m trial using different speeds and inclines, applying gears and sides as they normally would. Gear classification by the Smartphone (on the chest) and based on video recordings were compared. Formachine-learning, a collective database was compared to individual data. The Smartphone application identified the trials with fixed gears correctly in all cases. In the 950-m trial, participants executed 140 ± 22 cycles as assessed by video analysis, with the automatic Smartphone application giving a similar value. Based on collective data, gears were identified correctly 86.0% ± 8.9% of the time, a value that rose to 90.3% ± 4.1% (P < 0.01) with machine learning from individual data. Classification was most often incorrect during transition between gears, especially to or from G3. Identification was most often correct for skiers who made relatively few transitions between gears. The accuracy of the automatic procedure for identifying G2left, G2right, G3, G4left and G4right was 96%, 90%, 81%, 88% and 94%, respectively. The algorithm identified gears correctly 100% of the time when a single gear was used and 90% of the time when different gears were employed during a variable protocol. This algorithm could be improved with respect to identification of transitions between gears or the side employed within a given gear.

  • 45.
    Thakur, Aruna
    et al.
    Luleå University of Technology.
    Carr-Motyckova, Lenka
    Luleå University of Technology.
    Performance of a dynamic controller for layered streaming of video in internet2003In: 10th International Conference on Telecommunications: ICT 2003 ; February 23 - March 1, 2003, Sofitel Coralia Maeva Beach Hotel, Tahiti, Papeete, French Polynesia ; [conference proceedings], Piscataway, NJ: IEEE, 2003, Vol. 2, p. 1349-1355Conference paper (Refereed)
    Abstract [en]

    The layered video approach has been considered as one of the many approaches for solving the problems related to heterogeneity in the current Internet for real time applications. A number of schemes have been propounded taking into consideration only the network requirements. Another aspect is to a develop layering scheme based on a combination of network requirements and the perceptual quality of video. In this study, a post-codec controller has been described that sends the video sequence in an optimal way, taking into consideration the effect of the type of video sequence, the number of layers and distribution of frames among different layers of the perceptual quality of video, and the load on sender and bandwidth requirement. The controller has been tested in real network for two different configurations: (a) one sender and one receiver; and (b) one sender and many receivers connected in parallel. It has been observed that the quality of transmission improves by the use of the controller.

  • 46.
    Van-Eckmann, Nik
    Luleå University of Technology, Department of Arts, Communication and Education, Media, audio technology and experience production and theater.
    Wildlife Sound Recording: Dealing With The Distance And On-Axis Issues2017Licentiate thesis, monograph (Other academic)
    Abstract [en]

    In natural history filmmaking recording fauna vocalisation often produces difficult challenges especially when recording sound from a distance. The camera in many cases is able to solve these problems due to lens changes, but the microphone cannot do this, which creates major problems when combining sound and picture. This thesis using a multi disciplinary approach, looks at these problems in particular the 'Distance' and 'On-Axis' issues and attempts to solve them using both a theoretical and practical approach. The thesis consists of two parts, part one the theoretical section discusses the idiosyncrasies of natural history sound recording giving examples where the problems of actual situations have been resolved. Part two is an applied method or practical experimentation using technology designed to test certain theories in effectively dealing with the 'Distance' and 'On-Axis' issues. The practical experimentation takes place at various locations using avian subjects to demonstrate the problems and solutions when recording wildlife vocalisation. As a result of the tests, a remote-controlled microphone operating system was developed and tested in the field to ascertain its capabilities. Although still a prototype it has the potential through further development, to be a useful technological instrument for recording wildlife sound.

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    fulltext
  • 47.
    Zhohov, Roman
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Evaluating quality of experience and real-time performance of industrial internet of things2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Industrial Internet of Things (IIoT) is one of the key technologies of Industry 4.0 thatwill be an integral part of future smart and sustainable production. The current constitutedmodels for estimating Quality of Experience (QoE) are mainly targeting the multimediasystems. Present models for evaluating QoE, specifically leveraged by the expensivesubjective tests, are not applicable for IIoT applications. This work triggers the discussionon defining the QoE domain for IIoT services and applications. Industry-specific KPIs areproposed to assure QoE by linking business and technology domains. Tele-remote miningmachines are considered as a case study for developing the QoE model by taking intoaccount key challenges in QoE domain. As a result, QoE layered model is proposed, whichas an outcome predicts the QoE of IIoT services and applications in a form of pre-definedIndustrial KPIs. Moreover, software tool and analytical model is proposed to be used as anevaluation method for certain traffic types in the developed model.

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    fulltext
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