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  • 1. Ahmed, J.
    et al.
    Josefsson, T.
    Johnsson, A.
    Flinta, C.
    Moradi, F.
    Pasquini, R.
    Stadler, Rolf
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik. KTH, Skolan för elektroteknik och datavetenskap (EECS), Centra, ACCESS Linnaeus Centre.
    Automated diagnostic of virtualized service performance degradation2018Inngår i: IEEE/IFIP Network Operations and Management Symposium: Cognitive Management in a Cyber World, NOMS 2018, Institute of Electrical and Electronics Engineers Inc. , 2018, s. 1-9Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Service assurance for cloud applications is a challenging task and is an active area of research for academia and industry. One promising approach is to utilize machine learning for service quality prediction and fault detection so that suitable mitigation actions can be executed. In our previous work, we have shown how to predict service-level metrics in real-time just from operational data gathered at the server side. This gives the service provider early indications on whether the platform can support the current load demand. This paper provides the logical next step where we extend our work by proposing an automated detection and diagnostic capability for the performance faults manifesting themselves in cloud and datacenter environments. This is a crucial task to maintain the smooth operation of running services and minimizing downtime. We demonstrate the effectiveness of our approach which exploits the interpretative capabilities of Self- Organizing Maps (SOMs) to automatically detect and localize different performance faults for cloud services. © 2018 IEEE.

  • 2.
    B. da Silva Jr., Jose Mairton
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Optimization and Fundamental Insights in Full-Duplex Cellular Networks2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The next generations of cellular networks are expected to provide explosive data rate transmissions and very low latencies. To meet such demands, one of the promising wireless transmissions candidates is in-band full-duplex communications, which enable wireless devices to simultaneously transmit and receive on the same frequency channel. Full-duplex communications have the potential to double the spectral efficiency and reduce the transmission delays when compared to current half-duplex systems that either transmit or receive on the same frequency channel. Until recently, full-duplex communications have been hindered by the interference that leaks from the transmitter to its own receiver,the so-called self-interference. However, advances in digital and analog self-interference suppression techniques are making it possible to reduce the self-interference to manageable levels, and thereby make full-duplex a realistic candidate for advanced wireless systems.

    Although in-band full-duplex promises to double the data rates of existing wireless technologies, its deployment in cellular networks must be gradual due to the large number of legacy devices operating in half-duplex mode. When half-duplex devices are deployed in full-duplex cellular networks, the user-to-user interference may become the performance bottleneck. In such new interference situation, the techniques such as user pairing, frequency channel assignment, power control, beamforming, and antenna splitting become even more important than before, because they are essential to mitigate both the user-to-user interference and the residual self-interference. Moreover, introduction of full- duplex in cellular networks must comply with current multi-antenna systems and, possibly, transmissions in the millimeter-wave bands. In these new scenarios, no comprehensive analysis is available to understand the trade-offs in the performance of full-duplex cellular networks.

    This thesis investigates the optimization and fundamental insights in the design of spectral efficient and fair mechanisms in full-duplex cellular networks. The novel analysis proposed in this thesis suggests new solutions for maximizing full-duplex performance in the sub-6 GHz and millimeter-wave bands. The investigations are based on an optimization theory approach that includes distributed and nonconvex optimization with mixed integer-continuous variables, and novel extensions of Fast-Lipschitz optimization. The analysis sheds lights on fundamental questions such as which antenna architecture should be used and whether full-duplex in the millimeter-wave band is feasible. The results establish fundamental insights in the role of user pairing, frequency assignment, power control and beamforming; reveal the special behaviour between the self-interference and user- to-user interference; analyse the trade-offs between antenna sharing and splitting for uplink/downlink signal separation; and investigate the role of practical beamforming design in full-duplex millimeter-wave systems. This thesis may provide input to future standardization process of full-duplex communications.

  • 3.
    B. da Silva Jr., Jose Mairton
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Ghauch, Hadi
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Fodor, Gabor
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Fischione, Carlo
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    How to Split UL/DL Antennas in Full-DuplexCellular Networks2018Inngår i: IEEE International Conference on Communication (ICC’18): ThirdWorkshop on Full-Duplex Communications for Future Wireless Networks, Kansas City, MO, USA: IEEE Communications Society, 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    To further improve the potential of full-duplex com-munications, networks may employ multiple antennas at thebase station or user equipment. To this end, networks thatemploy current radios usually deal with self-interference andmulti-user interference by beamforming techniques. Althoughprevious works investigated beamforming design to improvespectral efficiency, the fundamental question of how to split theantennas at a base station between uplink and downlink infull-duplex networks has not been investigated rigorously. Thispaper addresses this question by posing antenna splitting as abinary nonlinear optimization problem to minimize the sum meansquared error of the received data symbols. It is shown that thisis an NP-hard problem. This combinatorial problem is dealt withby equivalent formulations, iterative convex approximations, anda binary relaxation. The proposed algorithm is guaranteed toconverge to a stationary solution of the relaxed problem with muchsmaller complexity than exhaustive search. Numerical resultsindicate that the proposed solution is close to the optimal in bothhigh and low self-interference capable scenarios, while the usuallyassumed antenna splitting is far from optimal. For large numberof antennas, a simple antenna splitting is close to the proposedsolution. This reveals that the importance of antenna splittingdiminishes with the number of antennas.

  • 4.
    B. da Silva Jr., Jose Mairton
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Nätverk och systemteknik.
    Ghauch, Hadi
    Fodor, Gabor
    Skoglund, Mikael
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Teknisk informationsvetenskap.
    Fischione, Carlo
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Smart Antenna Assignment is Essential in Full-Duplex Communications2019Inngår i: IEEE Transactions on Communications, ISSN 0090-6778, E-ISSN 1558-0857Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Full-duplex communications have the potential to almost double the spectralefficiency. To realize such a potentiality, the signal separation at base station’s antennasplays an essential role. This paper addresses the fundamentals of such separationby proposing a new smart antenna architecture that allows every antenna to beeither shared or separated between uplink and downlink transmissions. The benefitsof such architecture are investigated by an assignment problem to optimally assignantennas, beamforming and power to maximize the weighted sum spectral efficiency.We propose a near-to-optimal solution using block coordinate descent that divides theproblem into assignment problems, which are NP-hard, a beamforming and powerallocation problems. The optimal solutions for the beamforming and power allocationare established while near-to-optimal solutions to the assignment problems are derivedby semidefinite relaxation. Numerical results indicate that the proposed solution isclose to the optimum, and it maintains a similar performance for high and low residualself-interference powers. With respect to the usually assumed antenna separationtechnique and half-duplex transmission, the sum spectral efficiency gains increase withthe number of antennas. We conclude that our proposed smart antenna assignment forsignal separation is essential to realize the benefits of multiple antenna full-duplexcommunications.

  • 5.
    B. da Silva Jr., Jose Mairton
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Nätverk och systemteknik.
    Skouroumounis, Christodoulos
    University of Cyprus.
    Krikidis, Ioannis
    University of Cyprus.
    Fodor, Gabor
    Fischione, Carlo
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Datavetenskap, Nätverk och systemteknik.
    Energy Efficient Full-Duplex Networks2019Inngår i: Green Communications for Energy-EfficientWireless Systems and Networks / [ed] A. Zappone, J. Yang, J. S. Thompson, H. Suraweera, The Institution of Engineering and Technology (IET) , 2019Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    As the specifications of the 5th generation of cellular networks mature, the deployment phase is starting up. Hence, peaks of data rates in the order of tens of Gbit/s as well as more energy efficient deployments are expected. Nevertheless, the quick development of new applications and services encourage the research community to look beyond 5G and explore new technological components. Indeed, to meet the increasing demand for mobile broadband as well as internet of things type of services, the research and standardization communities are currently investigating novel physical and medium access layer technologies, including further virtualization of networks, the use of the lower Terahertz bands, even higher cell densification, and full-duplex (FD) communications.

     

    FD has been proposed as one of the enabling technologies to increase the spectral efficiency of conventional wireless transmission modes, by overcoming our prior understanding that it is not possible for radios to transmit and receive simultaneously on the same time-frequency resource. Due to this, we can also refer to FD communications as in-band FD. In-band FD transceivers have the potential of improving the attainable spectral efficiency of traditional wireless networks operating with half-duplex (HD) transceivers by a factor close to two. In addition to the spectral efficiency gains, full-duplex can provide gains in the medium access control layer, in which problems such as the hidden/exposed nodes and collision detection can be mitigated and the energy consumption can be reduced.

     

    Until recently, in-band FD was not considered as a solution for wireless networks due to the inherent interference created from the transmitter to its own receiver, the so-called self-interference (SI). However, recent advancements in antenna and analog/digital interference cancellation techniques demonstrate FD transmissions as a viable alternative to traditional HD transmissions. Given the recent architectural progression of 5G towards smaller cells, higher densification, higher number of antennas and utilizing the millimeter wave (mmWave) band, the integration of FD communications into such scenarios is appealing. In-band FD communications are suited for short range communication, and although the SI remains a challenge, the use of multiple antennas and the transmission in the mmWave band are allies that help to mitigate the SI in the spatial domain and provide even more gains for spectral and energy efficiency. To achieve the spectral and energy efficiency gains, it is important to understand the challenges and solutions, which can be roughly divided into resource allocation, protocol design, hardware design and energy harvesting. Hence, FD communications appears as an important technology component to improve the spectral and energy efficiency of current communication systems and help to meet the goals of 5G and beyond.

     

    The chapter starts with an overview of FD communications, including its challenges and solutions. Next, a comprehensive literature review of energy efficiency in FD communications is presented along with the key solutions to improve energy efficiency. Finally, we evaluate the key aspects of energy efficiency in FD communications for two scenarios: single-cell with multiple users in a pico-cell scenario, and a system level evaluation with macro- and small-cells with multiple users.

  • 6.
    Barros da Silva Jr., José Mairton
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik. Royal Inst Technol, KTH, Stockholm, Sweden..
    Ghauch, Hadi
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Fodor, Gabor
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Fischione, Carlo
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    How to Split UL/DL Antennas in Full-Duplex Cellular Networks2018Inngår i: 2018 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS WORKSHOPS (ICC WORKSHOPS), IEEE, 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    To further improve the potential of full-duplex communications, networks may employ multiple antennas at the base station or user equipment. To this end, networks that employ current radios usually deal with self-interference and multi-user interference by beamforming techniques. Although previous works investigated beamforming design to improve spectral efficiency, the fundamental question of how to split the antennas at a base station between uplink and downlink in full-duplex networks has not been investigated rigorously. This paper addresses this question by posing antenna splitting as a binary nonlinear optimization problem to minimize the sum mean squared error of the received data symbols. It is shown that this is an NP-hard problem. This combinatorial problem is dealt with by equivalent formulations, iterative convex approximations, and a binary relaxation. The proposed algorithm is guaranteed to converge to a stationary solution of the relaxed problem with much smaller complexity than exhaustive search. Numerical results indicate that the proposed solution is close to the optimal in both high and low self-interference capable scenarios, while the usually assumed antenna splitting is far from optimal. For large number of antennas, a simple antenna splitting is close to the proposed solution. This reveals that the importance of antenna splitting diminishes with the number of antennas.

  • 7.
    Barros da Silva Jr., José Mairton
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Nätverk och systemteknik.
    Sabharwal, Ashutosh
    Fodor, Gabor
    Fischione, Carlo
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    1-bit Phase Shifters Suffice for Large-Antenna Full-Duplex mmWave Communications2019Inngår i: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Millimeter-wave using large-antenna arrays is a key technological component forthe future cellular systems, where it is expected that hybrid beamforming along withquantized phase shifters will be used due to their implementation and cost efficiency.In this paper, we investigate the efficacy of full-duplex mmWave communicationwith hybrid beamforming using low-resolution phase shifters, without any analogself-interference cancellation. We formulate the problem of joint self-interferencesuppression and downlink beamforming as a mixed-integer nonconvex joint opti-mization problem. We propose LowRes, a near-to-optimal solution using penaltydual decomposition. Numerical results indicate that LowRes using low-resolutionphase shifters perform within 3% of the optimal solution that uses infinite phaseshifter resolution. Moreover, even a single quantization bit outperforms half-duplextransmissions, respectively by 29% and 10% for both low and high residual self-interference scenarios, and for a wide range of practical antenna to radio-chain ratios.Thus, we conclude that 1-bit phase shifters suffice for full-duplex millimeter-wavecommunications, without requiring any additional new analog hardware.

  • 8.
    Barros da Silva Jr., José Mairton
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Sabharwal, Ashutosh
    Rice Univ, Houston, TX USA..
    Fodor, Gabor
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik. Ericsson Res, Kista, Sweden..
    Fischione, Carlo
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Low Resolution Phase Shifters Suffice for Full-Duplex mmWave Communications2019Inngår i: 2019 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS WORKSHOPS (ICC WORKSHOPS), IEEE , 2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Full-duplex base-stations with half-duplex nodes, allowing simultaneous uplink and downlink from different nodes, have the potential to double the spectrum efficiency without adding additional complexity at mobile nodes. Hybrid beam forming is commonly used in millimeter wave systems for its implementation efficiency. An important element of hybrid beam-forming is quantized phase shifters. In this paper, we ask if low-resolution phase shifters suffice for beamforming-based full-duplex millimeter wave systems. We formulate the problem of joint design for both self-interference suppression and downlink beamforming as an optimization problem, which we solve using penalty dual decomposition to obtain a near-optimal solution. Numerical results indicate that low-resolution phase shifters can perform close to systems that use infinite phase shifter resolution, and that even a single quantization bit outperforms half-duplex transmissions in both low and high residual self-interference scenarios.

  • 9. Bjuhr, O.
    et al.
    Segeljakt, K.
    Addibpour, M.
    Heiser, F.
    Lagerström, Robert
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Software architecture decoupling at ericsson2017Inngår i: Proceedings - 2017 IEEE International Conference on Software Architecture Workshops, ICSAW 2017: Side Track Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2017, s. 259-262, artikkel-id 7958500Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In order to evaluate and increase modularity this paper combines a method for visualizing and measuring software architectures and two algorithms for decoupling. The combination is tested on a software system at Ericsson. Our analysis show that the system has one large cluster of components (18% of the system, a Core), all interacting with each other. By employing cluster and dominator analysis we suggest 19 dependencies to be removed in order to decouple the Core. Validating the analysis output with experts at Ericsson six of the suggested dependencies where deemed impossible to remove. By removing the remaining 13 dependencies Ericsson would improve the architecture of their system considerably, e.g. core size would go down to 5%.

  • 10. Blom, Rikard
    et al.
    Korman, Matus
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Robert, Lagerström
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Mathias, Ekstedt
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Analyzing attack resilience of an advanced meter infrastructure reference model2016Inngår i: Joint Workshop on Cyber-Physical Security and Resilience in Smart Grids (CPSR-SG), IEEE conference proceedings, 2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Advanced metering infrastructure (AMI) is a key component of the concept of smart power grids. Although several functional/logical reference models of AMI exist, they are not suited for automated analysis of properties such as cyber security. This paper briefly presents a reference model of AMI that follows a tested and even commercially adopted formalism allowing automated analysis of cyber security. Finally, this paper presents an example cyber security analysis, and discusses its results.

  • 11.
    Borsub, Jatesada
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Papadimitratos, Panagiotis
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Hardened registration process for participatory sensing2018Inngår i: WiSec 2018 - Proceedings of the 11th ACM Conference on Security and Privacy in Wireless and Mobile Networks, Association for Computing Machinery, Inc , 2018, s. 281-282Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Participatory sensing systems need to gather information from a large number of participants. However, the openness of the system is a double-edged sword: by allowing practically any user to join, the system can be abused by an attacker who introduces a large number of virtual devices. This poster proposes a hardened registration process for Participatory Sensing to raise the bar: registrations are screened through a number of defensive measures, towards rejecting spurious registrations that do not correspond to actual devices. This deprives an adversary from a relatively easy take-over and, at the same time, allows a flexible and open registration process.

  • 12. Camenisch, J.
    et al.
    Papadimitratos, Panagiotis
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Preface2018Inngår i: 17th International Conference on Cryptology and Network Security, CANS 2018, Springer Verlag , 2018Konferansepaper (Fagfellevurdert)
  • 13.
    Canat, Mert
    et al.
    KTH.
    Català, Nuria
    KTH.
    Jourkovski, Alexander
    KTH.
    Petrov, Svetlomir
    KTH.
    Wellme, Martin
    KTH.
    Lagerström, Robert
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Datavetenskap, Nätverk och systemteknik.
    Enterprise Architecture and Agile Development: Friends or Foes?2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Nowadays, both agile development and enterprise architecture are often employed in large organizations. However there is still some confusion if these can and should be used together, and there is not much research about the possible interplay. The aim of this study is to bring new knowledge to the field of enterprise architecture and its relation to agile development. Twelve qualitative interviews with professionals in different roles, such as developers and architects, have been carried out. The participants belong to five different companies and the information obtained from them has been used to compare opinions and stated challenges regarding agile and EA. We found that some common opinions among the interviewees are; 1) agile development and enterprise architecture can be combined, 2) there are clear communication problems among architects, different teams, and project owners, and 3) there is a lack of system and application reusability. © 2018 IEEE.

  • 14.
    Champati, Jaya Prakash
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Teknisk informationsvetenskap.
    Al-Zubaidy, Hussein
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Gross, James
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Teknisk informationsvetenskap.
    On the Distribution of AoI for the GI/GI/1/1 and GI/GI/1/2*Systems: Exact Expressions and Bounds2019Inngår i: IEEE CONFERENCE ON COMPUTER COMMUNICATIONS (IEEE INFOCOM 2019), IEEE , 2019, s. 37-45Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Since Age of Information (AoI) has been proposed as a metric that quantifies the freshness of information updates in a communication system, there has been a constant effort in understanding and optimizing different statistics of the AoI process for classical queueing systems. In addition to classical queuing systems, more recently, systems with no queue or a unit capacity queue storing the latest packet have been gaining importance as storing and transmitting older packets do not reduce AoI at the receiver. Following this line of research, we study the distribution of AoI for the GI/GI/1/1 and GI/GI/1/2* systems, under non-preemptive scheduling. For any single-source-single-server queueing system, we derive, using sample path analysis, a fundamental result that characterizes the AoI violation probability, and use it to obtain closed-form expressions for D/GI/1/1, M/GI/1/1 as well as systems that use zero-wait policy. Further, when exact results are not tractable, we present a simple methodology for obtaining upper bounds for the violation probability for both GI/GI/1/1 and GI/GI/1/2* systems. An interesting feature of the proposed upper bounds is that, if the departure rate is given, they overestimate the violation probability by at most a value that decreases with the arrival rate. Thus, given the departure rate and for a fixed average service, the bounds are tighter at higher utilization.

  • 15.
    Du, Rong
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Optimal Networking in Wirelessly Powered Sensor Networks2018Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Wireless sensor networks (WSNs) are nowadays widely used for the long-term monitoring of small or large regions, such as lakes, forests, cities, and industrial areas. The performance of a WSN typically consists of two aspects: i) the monitoring performance, e.g., the accuracy and the timeliness of the measurements or estimations produced by the sensor nodes of the WSN; and ii) the lifetime, i.e., how long the WSN can sustain such a performance. Naturally, we would like to have the monitoring performance as good as possible, and the lifetime as long as possible. However, in traditional WSNs, the sensor nodes generally have limited resources, especially in terms of battery capacity. If the nodes make measurements and report them frequently for a good monitoring performance, they drain their batteries and  this leads to a severely shortened network lifetime. Conversely, the sensors can have a longer lifetime by sacrificing the monitoring performance. It shows the inherent trade-off between the monitoring performance and the lifetime in WSNs.

    We can overcome the limitations of the trade-off described above by wireless energy transfer (WET), where we can provide the sensor nodes with additional energy remotely. The WSNs with WET are called wirelessly powered sensor networks (WPSNs). In a WPSN, dedicated energy sources, e.g., static base stations or mobile chargers, transmit energy via radio frequency (RF) waves to the sensor nodes. The nodes can store the energy in their rechargeable batteries and use it later when it is needed. In so doing, they can use more energy to perform the sensing tasks. Thus, WET is a solution to improve the monitoring performance and lifetime at the same time.  As long as the nodes receive more energy than they consume, it is possible that the WSN be immortal, which is impossible in traditional WSNs. 

    Although WPSNs can potentially break the trade-off between monitoring performance and lifetime, they also bring many fundamental design and performance analysis challenges. Due to the safety issues, the power that the dedicated energy sources can use is limited. The propagation of the RF waves suffers high path losses. Therefore, the energy received by the sensor nodes is much less than the energy transmitted from the sources. As a result, to have a good WSN performance, we should optimize the energy transmission on the energy source side and the energy consumption on the nodes side. Compared to the traditional WSN scenarios where we can only optimize the sensing and data communication strategies, in WPSNs, we have an additional degree of freedom, i.e., the optimization of the energy transmission strategies. This aspect brings new technical challenges and problems that have not been studied in the traditional WSNs. Several novel research questions arise, such as when and how to transmit the energy, and which energy source should transmit. Such questions are not trivial especially when we jointly consider the energy consumption part.

    This thesis contributes to answer the questions above. It consists of three contributions as follows.

    In the first contribution, we consider a WPSN with single energy base stations (eBS) and multiple sensor nodes to monitor several separated areas of interest. The eBS has multiple antennas, and it uses energy beamforming to transmit energy to the nodes. Notice that, if we deploy multiple sensor nodes at the same area, these nodes may receive the energy from the eBS at the same time and they can reduce the energy consumption by applying sleep/awake mechanism. Therefore, we jointly study the deployment of the nodes, the energy transmission of the eBS, and the node activation. The problem is an integer optimization, and we decouple the problem into a node deployment problem and a scheduling problem. We provide a greedy-based algorithm to solve the problem, and show its performance in terms of optimality.

    The second contribution of the thesis starts by noticing that wireless channel state information (CSI) is important for energy beamforming. The more energy that an eBS spends in channel acquisition, the more accurate CSI it will have, thus improving the energy beamforming performance. However, if the eBS spends too much energy on channel acquisition, it will have less energy for WET, which might reduce the energy that is received by the sensor nodes. We thus investigate how much energy the eBS should spend in channel acquisition, i.e., we study the power allocation problem in channel acquisition and energy beamforming for WPSNs. We consider the general optimal channel acquisition and show that the problem is non-convex. Based on the idea of bisection search, we provide an algorithm to find the optimal solution for the single eBS cases, and a closed-form solution for the case where the eBS uses orthogonal pilot transmission, least-square channel estimation, and maximum ratio transmission for WET. The simulations show that the algorithm converges fast, and the performance is close to the theoretical upper bound.

    In the third contribution, we consider a joint energy beamforming and data routing problem for WPSNs. More specifically, we investigate the WPSNs consisting of multiple eBSs, multiple sensor nodes, and a sink node. Based on the received energy, the sensor nodes need to decide how to route their data. The problem aims at maximizing the minimum sensing rate of the sensor nodes while guaranteeing that the received energy of each node is no less than that is consumed. Such a problem is non-convex, and we provide a centralized solution algorithm based on a semi-definite programming transformation. We extend this approach with a distributed algorithm using alternating direction method of multipliers (ADMM). We prove that the centralized algorithm achieves the optimal energy beamforming and routing, and we show by simulation that the distributed one converges to the optimal solution. Additionally, for the cases where the energy beamforming options are pre-determined, we study the problem of finding the energy that should be spent on each vector. We observe that, if the pre-determined beamforming options are chosen wisely, their performance is close to the optimal.

    The results of the thesis show that WET can prolong the lifetime of WSNs, and even make them work sufficiently long for general monitoring applications. More importantly, we should optimize the WPSN by considering both the energy provision and the energy consumption part. The studies of the thesis have the potential to be used in many Internet of Things (IoT) systems in smart cities, such as water distribution lines and building monitoring.

  • 16.
    Du, Rong
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Fischione, Carlo
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Power Allocation for Channel Estimation and EnergyBeamforming in Wirelessly Powered Sensor Networks2018Inngår i: Proceedings of IEEE International Conference on Communications Workshops, 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Wirelessly powered sensor networks (WPSNs) are becoming increasingly important to monitor many internet-of-things systems. In these WPSNs, dedicated base stations (BSs) with multiple antennas charge the sensor nodes without the need of replacing their batteries thanks to two essential procedures: i)  getting of the channel state information of the nodes by sending pilots, and based on this, ii) performing energy beamforming to transmit energy to the nodes. However, the BSs have limited power budget and thus these two procedures are not independent, contrarily to what  is assumed in some previous studies. In this paper, we investigate the novel problem of how to optimally allocate the power for channel estimation and energy transmission. Although the problem is non-convex, we provide a new solution approach and a performance analysis in terms of optimality and complexity. We also provide a closed form solution for the case where the channels are estimated based on a least square estimation. The simulations show a gain of approximately 10% in allocating the power optimally, and the importance of improving the channel estimation efficiency.

  • 17.
    Du, Rong
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Gkatzikis, Lazaros
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Reglerteknik.
    Fischione, Carlo
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Xiao, Ming
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Teknisk informationsvetenskap.
    On Maximizing Sensor Network Lifetime by Energy Balancing2018Inngår i: IEEE Transactions on Control of Network Systems, ISSN 2325-5870, Vol. 5, nr 3Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Many physical systems, such as water/electricity distribution networks, are monitored by battery-powered wireless-sensor networks (WSNs). Since battery replacement of sensor nodes is generally difficult, long-term monitoring can be only achieved if the operation of the WSN nodes contributes to long WSN lifetime. Two prominent techniques to long WSN lifetime are 1) optimal sensor activation and 2) efficient data gathering and forwarding based on compressive sensing. These techniques are feasible only if the activated sensor nodes establish a connected communication network (connectivity constraint), and satisfy a compressive sensing decoding constraint (cardinality constraint). These two constraints make the problem of maximizing network lifetime via sensor node activation and compressive sensing NP-hard. To overcome this difficulty, an alternative approach that iteratively solves energy balancing problems is proposed. However, understanding whether maximizing network lifetime and energy balancing problems are aligned objectives is a fundamental open issue. The analysis reveals that the two optimization problems give different solutions, but the difference between the lifetime achieved by the energy balancing approach and the maximum lifetime is small when the initial energy at sensor nodes is significantly larger than the energy consumed for a single transmission. The lifetime achieved by energy balancing is asymptotically optimal, and that the achievable network lifetime is at least 50% of the optimum. Analysis and numerical simulations quantify the efficiency of the proposed energy balancing approach.

  • 18.
    Du, Rong
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Ozcelikkale, Ayca
    Fischione, Carlo
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Xiao, Ming
    Towards Immortal Wireless Sensor Networks by Optimal Energy Beamforming and Data Routing2018Inngår i: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 17, nr 8, s. 5338-5352Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The lifetime of a wireless sensor network (WSN) determines how long the network can be used to monitor the area of interest. Hence, it is one of the most important performance metrics for WSN. The approaches used to prolong the lifetime can be briefly divided into two categories: reducing the energy consumption, such as designing an efficient routing, and providing extra energy, such as using wireless energy transfer (WET) to charge the nodes. Contrary to the previous line of work where only one of those two aspects is considered, we investigate these two together. In particular, we consider a scenario where dedicated wireless chargers transfer energy wirelessly to sensors. The overall goal is to maximize the minimum sampling rate of the nodes while keeping the energy consumption of each node smaller than the energy it receives. This is done by properly designing the routing of the sensors and the WET strategy of the chargers. Although such a joint routing and energy beamforming problem is non-convex, we show that it can be transformed into a semi-definite optimization problem (SDP). We then prove that the strong duality of the SDP problem holds, and hence the optimal solution of the SDP problem is attained. Accordingly, the optimal solution for the original problem is achieved by a simple transformation. We also propose a low-complexity approach based on pre-determined beamforming directions. Moreover, based on the alternating direction method of multipliers (ADMM), the distributed implementations of the proposed approaches are studied. The simulation results illustrate the significant performance improvement achieved by the proposed methods. In particular, the proposed energy beamforming scheme significantly out-performs the schemes where one does not use energy beamforming, or one does not use optimized routing. A thorough investigation of the effect of system parameters, including the number of antennas, the number of nodes, and the number of chargers, on the system performance is provided. The promising convergence behaviour of the proposed distributed approaches is illustrated.

  • 19.
    Du, Rong
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Santi, Paolo
    Xiao, Ming
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Teknisk informationsvetenskap.
    Vasilakos, Athanasios
    Fischione, Carlo
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    The sensable city: A survey on the deployment and management for smart city monitoringInngår i: IEEE Communications Surveys and Tutorials, ISSN 1553-877X, E-ISSN 1553-877XArtikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In last two decades, various monitoring systems have been designed and deployed in urban environments, toward the realization of the so called smart cities. Such systems are based on both dedicated sensor nodes, and ubiquitous but not dedicated devices such as smart phones and vehicles' sensors. When we design sensor network monitoring systems for smart cities, we have two essential problems: node deployment and sensing management. These design problems are challenging, due to large urban areas to monitor, constrained locations for deployments, and heterogeneous type of sensing devices. There is a vast body of literature from different disciplines that have addressed these challenges. However, we do not have yet a comprehensive understanding and sound design guidelines. This paper addresses such a research gap and provides an overview of the theoretical problems we face, and what possible approaches we may use to solve these problems. Specifically, this paper focuses on the problems on both the deployment of the devices (which is the system design/configuration part) and the sensing management of the devices (which is the system running part). We also discuss how to choose the existing algorithms in different type of monitoring applications in smart cities, such as structural health monitoring, water pipeline networks, traffic monitoring. We finally discuss future research opportunities and open challenges for smart city monitoring.

  • 20.
    Du, Rong
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Shokri-Ghadikolaei, Hossein
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Fischione, Carlo
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Wirelessly-powered Sensor Networks: Power Allocation for Channel Estimation and Energy beamformingInngår i: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Wirelessly-powered sensor networks (WPSNs) are becoming increasingly important to monitor many internet-of-things systems. We consider a WPSN where a multiple-antenna base station, dedicated for energy transmission, sends pilot signals to estimate the channel state information and consequently shapes the energy beams toward the sensor nodes. Given a fixed energy budget at the base station, in this paper, we investigate the novel problem of optimally allocating the power for the channel estimation and for the energy transmission. We formulate this problem for general channel estimation and beamforming schemes, which turns out to be non-convex. We provide a new solution approach and a performance analysis in terms of optimality and complexity. We also present a closed-form solution for the case where the channels are estimated based on a least square channel estimation and a maximum ratio transmit beamforming scheme. The analysis and simulations indicate a significant gain in terms of the network sensing rate, compared to the fixed power allocation, and the importance of improving the channel estimation efficiency.

  • 21.
    Du, Rong
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Xiao, Ming
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Teknisk informationsvetenskap.
    Fischione, Carlo
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Optimal Node Deployment and Energy Provision for Wirelessly Powered Sensor Networks2018Inngår i: IEEE Journal on Selected Areas in Communications, ISSN 0733-8716, E-ISSN 1558-0008, Vol. 37, nr 2, s. 407-423Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In a typical wirelessly powered sensor network (WPSN), wireless chargers provide energy to sensor nodes by using wireless energy transfer (WET). The chargers can greatly improve the lifetime of a WPSN using energy beamforming by a proper charging scheduling of energy beams. However, the supplied energy still may not meet the demand of the energy of the sensor nodes. This issue can be alleviated by deploying redundant sensor nodes, which not only increase the total harvested energy, but also decrease the energy consumption per node provided that an efficient  scheduling of the sleep/awake of the nodes is performed. Such a problem of joint optimal sensor deployment, WET scheduling, and node activation is posed and investigated in this paper. The problem is an integer optimization that is challenging due to the binary decision variables and non-linear constraints. Based on the analysis of the necessary condition such that the WPSN be immortal, we decouple the original problem into a node deployment problem and a charging and activation scheduling problem. Then, we propose an algorithm and prove that it achieves the optimal solution under a mild condition. The simulation results show that the proposed algorithm reduces the needed nodes to deploy by approximately 16%, compared to a random-based approach. The simulation also shows if the battery buffers are large enough, the optimality condition will be easy to meet.

  • 22.
    Ekstedt, Mathias
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Industriella informations- och styrsystem.
    Johnson, Pontus
    KTH, Skolan för elektro- och systemteknik (EES), Industriella informations- och styrsystem.
    Lagerström, Robert
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Gorton, Dan
    Foreseeti AB, Sweden.
    Nydren, Joakim
    Foreseeti AB, Sweden.
    Shahzad, Khurram
    Foreseeti AB, Sweden.
    securiCAD by foreseeti: A CAD tool for enterprise cyber security management2015Inngår i: Proceedings of the 2015 IEEE 19th International Enterprise Distributed Object Computing Conference Workshops and Demonstrations, EDOCW 2015, 2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents a CAD tool for enterprise cyber security management called securiCAD. It is a software developed during ten years of research at KTH Royal Institute of Technology, and it is now being commercialized by foreseeti (a KTH spin-off company). The idea of the tool is similar to CAD tools used when engineers design and test cars, buildings, etc. Specifically, the securiCAD user first models the IT environment, an existing one or one under development, and then securiCAD, using attack graphs, calculates and highlights potential weaknesses and avenues of attacks. The main benefits with securiCAD are; 1) built in security expertise, 2) visualization, 3) holistic security assessments, and 4) scenario comparison (decision-making) capabilities.

  • 23.
    Ekstedt, Mathias
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Lapalme, J.
    Franke, U.
    Schulte, S.
    Message from the EDOC 2018 Workshop and Demo Chairs2018Inngår i: 22nd IEEE International Enterprise Distributed Object Computing Conference Workshops, EDOCW 2018, ISSN 1541-7719, Vol. 2018-October, artikkel-id 8536091Artikkel i tidsskrift (Fagfellevurdert)
  • 24.
    Elsner, Daniel
    et al.
    TU Munich.
    Khosroshahi, Pouya
    TU Munich.
    MacCormack, Alan
    Harvard.
    Lagerström, Robert
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Multivariate Unsupervised Machine Learning for Anomaly Detection in Enterprise Applications2019Konferansepaper (Fagfellevurdert)
  • 25. Enyioha, Chinwendu
    et al.
    Magnusson, Sindri
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik. KTH - Royal Institute of Technology.
    Heal, Kathryn
    Na, Li
    Carlo, Fischione
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Tarokh, Vahid
    On Variability of Renewable Energy and Online Power Allocation2018Inngår i: IEEE Transactions on Power Systems, ISSN 0885-8950, E-ISSN 1558-0679, Vol. 33, nr 1, s. 451-462Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    As electric power system operators shift from conventional energy to renewable energy sources, power distribution systems will experience increasing fluctuations in supply. These fluctuations present the need to not only design online decentralized power allocation algorithms, but also characterize how effective they are given fast-changing consumer demand and generation. In this paper, we present an online decentralized dual descent (OD3) power allocation algorithm and determine (in the worst case) how much of observed social welfare can be explained by fluctuations in generation capacity and consumer demand. Convergence properties and performance guarantees of the OD3 algorithm are analyzed by characterizing the difference between the online decision and the optimal decision. We demonstrate validity and accuracy of the theoretical results in the paper through numerical experiments using real power generation data.

  • 26.
    Forsby, Filip
    et al.
    KTH.
    Furuhed, M.
    Papadimitratos, Panagiotis
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Raza, S.
    Lightweight X.509 Digital Certificates for the Internet of Things2018Inngår i: 3rd International Conference on Interoperability in IoT, InterIoT 2017 on conjunction with 4th International Conference on Safety and Security in Internet of Things, SaSeIoT 2017, Springer, 2018, Vol. 242, s. 123-133Konferansepaper (Fagfellevurdert)
    Abstract [en]

    X.509 is the de facto digital certificate standard used in building the Public Key Infrastructure (PKI) on the Internet. However, traditional X.509 certificates are too heavy for battery powered or energy harvesting Internet of Things (IoT) devices where it is crucial that energy consumption and memory footprints are as minimal as possible. In this paper we propose, implement, and evaluate a lightweight digital certificate for resource-constrained IoT devices. We develop an X.509 profile for IoT including only the fields necessary for IoT devices, without compromising the certificate security. Furthermore, we also propose compression of the X.509 profiled fields using the contemporary CBOR encoding scheme. Most importantly, our solutions are compatible with the existing X.509 standard, meaning that our profiled and compressed X.509 certificates for IoT can be enrolled, verified and revoked without requiring modification in the existing X.509 standard and PKI implementations. We implement our solution in the Contiki OS and perform evaluation of our profiled and compressed certificates on a state-of-the-art IoT hardware.

  • 27.
    Ghasemi-Goojani, Shahab
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Papadimitratos, Panagiotis
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    On the Capacity of Gaussian "Dirty" Z-Interference Channel with Common State2018Inngår i: 2018 52ND ANNUAL CONFERENCE ON INFORMATION SCIENCES AND SYSTEMS (CISS), IEEE , 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A class of Gaussian Z-interference channels with state is investigated in the regime of high state power with two transmitters communicating two independent messages through a "dirty" Z-interference channel with state. Transmitter 1 (primary user) interferes with receiver 2, while transmitter 2 (secondary user) does not interfere with receiver 1. In our model, we assume that both states are the same. Using lattice coding schemes, we obtain achievable rate-regions to characterize the boundary of the capacity region either fully or partially. Surprisingly, we observe that the achievable rate-region under a common state can include some points out of the rate-region when the channel is only corrupted by a state, i.e., when the additional interference is not harmful for the channel.

  • 28.
    Ghasemi-Goojani, Shahab
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Papadimitratos, Panagiotis
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    On the Capacity of State-Dependent Gaussian Z-Interference Channel2019Inngår i: Proceedings of 2018 International Symposium on Information Theory and Its Applications, ISITA 2018, Institute of Electrical and Electronics Engineers Inc. , 2019, s. 653-657Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We study the State-Dependent Gaussian Z-Interference Channel (SDG-ZIC), with two senders transmitting two independent messages through a Gaussian Z-interference channel with the same state. Transmitter 1 interferes with receiver 2, while transmitter 2 does not interfere with receiver 1. In addition, both receivers suffer from the same but differently scaled random state sequence, which is non-causally known at both transmitters. As mentioned in [1], the challenge here is to fully cancel differently scaled states at both receivers. Proposing transmission schemes based on nested lattice codes, we show that under some new conditions, the state at both receivers can be fully canceled and the capacity region can be fully achieved.

  • 29.
    Ghasemi-Goojani, Shahab
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Papadimitratos, Panagiotis
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    The Symmetric Two-Hop Channel with an Untrusted Relay2019Inngår i: Proceedings of 2018 International Symposium on Information Theory and Its Applications, ISITA 2018, Institute of Electrical and Electronics Engineers Inc. , 2019, s. 673-677Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We study, using information-theoretic security methods, the so-called symmetric two-hop channel with an untrusted relay. In this model, a source wants to send its message reliably and securely to the destination through an honest but curious relay. The relay acts as a passive eavesdropper. Our investigation, in line with the relevant literature, seeks to determine what rate, termed secrecy rate, is achievable. To do that, we consider a typical setting, with the destination cooperating with the source, sending a 'scrambling' signal to conceal the message from the relay. To derive the achievable secrecy rate, we propose a novel scheme based on nested lattice codes. We show that our scheme outperforms all existing schemes and it achieves the outer bound for this channel model within 0.33 bits.

  • 30.
    Ghauch, Hadi
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Kim, Taejoon
    Univ Kansas, Dept EECS, Lawrence, KS 66045 USA..
    Fischione, Carlo
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Skoglund, Mikael
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Teknisk informationsvetenskap.
    Compressive Sensing with Applications to Millimeter-wave Architectures2019Inngår i: 2019 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH AND SIGNAL PROCESSING (ICASSP), IEEE , 2019, s. 7834-7838Konferansepaper (Fagfellevurdert)
    Abstract [en]

    To make the system available at low-cost, millimeter-ave (mmWave) multiple-input multiple-output (MIMO) architectures employ analog arrays, which are driven by a limited number of radio frequency (RF) chains. One primary challenge of using large hybrid analog-digital arrays is that the digital baseband cannot directly access the signal to/from each antenna. To address this limitation, recent research has focused on retransmissions, iterative precoding, and subspace decomposition methods. Unlike these approaches that exploited the channel's low-rank, in this work we exploit the sparsity of the received signal at both the transmit/receive antennas. While the signal itself is de facto dense, it is well-known that most signals are sparse under an appropriate choice of basis. By delving into the structured compressive sensing (CS) framework and adapting them to variants of the mmWave hybrid architectures, we provide methodologies to recover the analog signal at each antenna from the (low-dimensional) digital signal. Moreover, we characterizes the minimal numbers of measurement and RF chains to provide this recovery, with high probability. We discuss their applications to common variants of the hybrid architecture. By leveraging the inherent sparsity of the received signal, our analysis reveals that a hybrid MIMO system can be " turned into" a fully digital one: the number of needed RF chains increases logarithmically with the number of antennas.

  • 31.
    Ghauch, Hadi
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Kim, Taejoon
    KTH, Skolan för elektroteknik och datavetenskap (EECS). City University of Hong Kong.
    Skoglund, Mikael
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Teknisk informationsvetenskap.
    Fischione, Carlo
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Low-Overhead Coordination in Sub-28 Millimeter-Wave Networks2018Inngår i: 2018 IEEE International Conference on Communications (ICC), 2018Konferansepaper (Fagfellevurdert)
  • 32.
    Ghauch, Hadi
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Rahman, Muhammad Mahboob Ur
    KTH. Informat Technol Univ, Dept Elect Engn, Lahore 54000, Pakistan..
    Imtiaz, Sahar
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Teknisk informationsvetenskap.
    Qvarfordt, Christer
    Huawei Technol, S-16440 Kista, Sweden..
    Skoglund, Mikael
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Teknisk informationsvetenskap.
    Gross, James
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Teknisk informationsvetenskap.
    User Assignment in C-RAN Systems: Algorithms and Bounds2018Inngår i: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 17, nr 6, s. 3889-3902Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, we investigate the problem of mitigating interference between so-called antenna domains of a cloud radio access network (C-RAN). In contrast to previous work, we turn to an approach utilizing primarily the optimal assignment of users to central processors in a C-RAN deployment. We formulate this user assignment problem as an integer optimization problem and propose an iterative algorithm for obtaining a solution. Motivated by the lack of optimality guarantees on such solutions, we opt to find lower bounds on the problem and the resulting interference leakage in the network. We thus derive the corresponding Dantzig-Wolfe decomposition, formulate the dual problem, and show that the former offers a tighter bound than the latter. We highlight the fact that the bounds in question consist of linear problems with an exponential number of variables and adapt the column generation method for solving them. In addition to shedding light on the tightness of the bounds in question, our numerical results show significant sum-rate gains over several comparison schemes. Moreover, the proposed scheme delivers similar performance as weighted minimum mean squared-error (MMSE) with a significantly lower complexity (around 10 times less).

  • 33. Guerreiro, Sérgio
    et al.
    Guédria, Wided
    Lagerström, Robert
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    van Kervel, Steven
    A Meta Model for interoperability of Secure Business Transaction using BlockChain and DEMO2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Business transactions executed between organizations and individuals are largely operated on digital environments, conducting to an industrial interoperability challenge demanding secure environments to cooperate safely, therefore increasing credibility, and trust ability between end-users. This paper conceptualizes and prescribes a fine-grained control solution for the execution of business transactions involving critical assets, and using a human-based coordination and interaction design to minimize the negative impacts of security risks, the non-conformable operation and the coarse-grained control. This solution integrates the DEMO-based Enterprise Operating System (EOS) with BlockChain as a way to redesign, and distribute globally, a set of services that are founded in a human-oriented approach, and therefore, offering trust, authenticity, resilience, robustness against fraud and identification and mitigation of risk. The impacts for organizations and individuals are manifold: a security risk-based solution for end-users with budgetary constraints; educate on cyber security issues; and augment the trust for digital business processes environments.

  • 34.
    Gupta, Gagan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Monitoring Water Distribution Network using Machine Learning2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Water is an important natural resource. It is supplied to our home by water distribution network thatis owned and maintained by water utility companies. Around one third of water utilities across the globereport a loss of 40% of clean water due to leakage. The increase in pumping, treatment and operationalcosts are pushing water utilities to combat water loss by developing methods to detect, locate, and xleaks. However, traditional pipeline leakage detection methods require periodical inspection with humaninvolvement, which makes it slow and inecient for leakage detection in a timely manner. An alternativeis on-line, continuous, real-time monitoring of the network facilitating early detection and localization ofthese leakages. This thesis aims to nd such an alternative using various Machine Learning techniques.For a water distribution network, a novel algorithm is proposed based on the concept of dominantnodes from graph theory. The algorithm nds the number of sensors needed and their correspondinglocations in the network. The network is then sub-divided into several leakage zones, which serves as abasis for leak localization in the network. Thereafter, leakages are simulated in the network virtually,using hydraulic simulation software. The obtained time series pressure data from the sensor nodes ispre-processed using one-dimensional wavelet series decomposition by using daubechies wavelet to extractfeatures from the data. It is proposed to use this feature extraction procedure at every sensor nodelocally, which reduces the transmitted data to the central hub over the cloud thereby reducing the energyconsumption for the IoT sensor in real world.For water leakage detection and localization, a procedure for obtaining training data is proposed,which serves as a basis for recognition of patterns and regularities in the data using supervised Machinelearning techniques such as Logistic Regression, Support Vector Machine, and Articial Neural Network.Furthermore, ensemble of these trained model is used to build a better model for leakage detection andits localization. In addition, Random Forest algorithm is trained and its performance is compared tothe obtained ensemble of earlier models. Also, leak size estimation is performed using Support VectorRegression algorithm.It is observed that the sensor node placement using proposed algorithm provides a better leakage localizationresolution than random deployment of sensor. Furthermore, it is found that leak size estimationusing Support Vector Regression algorithm provides a reasonable accuracy. Also, it is noticed that RandomForest algorithm performs better than the ensemble model except for the low leakage scenario. Thus,it is concluded to estimate the leak size rst, based on this estimation for small leakage case ensemblemodels can be applied while for large leakage case only Random Forest can be used.

  • 35.
    He, Qing
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Dán, Gyorgy
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Fodor, Viktoria
    Joint Assignment and Scheduling for Minimizing Age of Correlated Information2019Inngår i: IEEE/ACM Transactions on Networking, ISSN 1063-6692, E-ISSN 1558-2566Artikkel i tidsskrift (Fagfellevurdert)
  • 36.
    He, Qing
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Dán, György
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Fodor, Viktória
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Minimizing Age of Correlated Information for Wireless Camera Networks2018Inngår i: IEEE INFOCOM 2018 - IEEE CONFERENCE ON COMPUTER COMMUNICATIONS WORKSHOPS (INFOCOM WKSHPS), IEEE , 2018, s. 547-552Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Freshness of information is of critical importance for a variety of applications based on wireless camera networks where multi-view image processing is required. In this study, we propose to jointly optimize the use of communication and computing resources such that information from multiple views is delivered is obtained in a timely fashion. To this end, we extend the concept of age of information to capture packets carrying correlated data. We consider the joint optimization of processing node assignment and camera transmission policy, so as to minimize the maximum peak age of information from all sources. We formulate the multi-view age minimization problem (MVAM) and prove that it is NP-hard. We provide fundamental results including tractable cases and optimality conditions. To solve the MVAM efficiently, we develop a modular optimization algorithm following a decomposition approach. Numerical results show that, by employing our approach, the maximum peak age is significantly reduced in comparison to a traditional centralized solution with minimum-time scheduling.

  • 37. Hollick, M.
    et al.
    Papadimitratos, Panagiotis
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Enck, W.
    Foreword2016Inngår i: 9th ACM Conference on Security and Privacy in Wireless and Mobile Networks, WiSec 2016Artikkel i tidsskrift (Fagfellevurdert)
  • 38.
    Hylamia, Abdullah
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Varshney, Ambuj
    Uppsala Univ, Uppsala, Sweden..
    Soleiman, Andreas
    Uppsala Univ, Uppsala, Sweden..
    Papadimitratos, Panagiotis
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Rohner, Christian
    Uppsala Univ, Uppsala, Sweden..
    Voigt, Thiemo
    Uppsala Univ, Uppsala, Sweden.;RISE SICS, Stockholm, Sweden..
    Demo: Towards Battery-free Radio Tomographic Imaging2018Inngår i: WISEC'18: PROCEEDINGS OF THE 11TH ACM CONFERENCE ON SECURITY & PRIVACY IN WIRELESS AND MOBILE NETWORKS, ACM Digital Library, 2018, s. 293-295Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Radio Tomographic Imaging (RTI) enables novel radio frequency (RF) sensing applications such as intrusion detection systems by observing variations in radio links caused by human actions. RTI applications are, however, severely limited by the requirement to retrofit existing infrastructure with energy-expensive sensors. In this demonstration, we present our ongoing efforts to develop the first battery-free RTI system that operates on minuscule amounts of energy harvested from the ambient environment. Our system eliminates the energy-expensive components employed on state-of-the-art RTI systems achieving two orders of magnitude lower power consumption. Battery-free operation enables a sustainable deployment, as RTI sensors could be deployed for long periods of time with little maintenance effort. Our demonstration showcases an intrusion detection scenario enabled by our system.

  • 39.
    Hylamia, Sam
    et al.
    KTH.
    Spanghero, Marco
    KTH.
    Varshney, Ambuj
    Uppsala University, Uppsala, Sweden.
    Voigt, Thiemo
    Uppsala University and RISE SICS, Uppsala and Stockholm, Sweden.
    Papadimitratos, Panagiotis
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Security on harvested power2018Inngår i: WiSec 2018 - Proceedings of the 11th ACM Conference on Security and Privacy in Wireless and Mobile Networks, Association for Computing Machinery, Inc , 2018, s. 296-298Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Security mechanisms for battery-free devices have to operate under severe energy constraints relying on harvested energy. This is challenging, as the energy harvested from the ambient environment is usually scarce, intermittent and unpredictable. One of the challenges for developing security mechanisms for such settings is the lack of hardware platforms that recreate energy harvesting conditions experienced on a battery-free sensor node. In this demonstration, we present an energy harvesting security (EHS) platform that enables the development of security algorithms for battery-free sensors. Our results demonstrate that our platform is able to harvest sufficient energy from indoor lighting to support several widely used cryptography algorithms.

  • 40.
    Imtiaz, Sahar
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Teknisk informationsvetenskap.
    Koudouridis, Georgios P.
    Ghauch, Hadi
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Gross, James
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Teknisk informationsvetenskap.
    Random forests for resource allocation in 5G cloud radio access networks based on position information2018Inngår i: EURASIP Journal on Wireless Communications and Networking, ISSN 1687-1472, E-ISSN 1687-1499, Vol. 2018, nr 1, artikkel-id 142Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Next generation 5G cellular networks are envisioned to accommodate an unprecedented massive amount of Internet of things (IoT) and user devices while providing high aggregate multi-user sum rates and low latencies. To this end, cloud radio access networks (CRAN), which operate at short radio frames and coordinate dense sets of spatially distributed radio heads, have been proposed. However, coordination of spatially and temporally denser resources for larger sets of user population implies considerable resource allocation complexity and significant system signalling overhead when associated with channel state information (CSI)-based resource allocation (RA) schemes. In this paper, we propose a novel solution that utilizes random forests as supervised machine learning approach to determine the resource allocation in multi-antenna CRAN systems based primarily on the position information of user terminals. Our simulation studies show that the proposed learning based RA scheme performs comparably to a CSI-based scheme in terms of spectral efficiency and is a promising approach to master the complexity in future cellular networks. When taking the system overhead into account, the proposed learning-based RA scheme, which utilizes position information, outperforms legacy CSI-based scheme by up to 100%. The most important factor influencing the performance of the proposed learning-based RA scheme is antenna orientation randomness and position inaccuracies. While the proposed random forests scheme is robust against position inaccuracies and changes in the propagation scenario, we complement our scheme with three approaches that restore most of the original performance when facing random antenna orientations of the user terminal.

  • 41.
    Iqbal, Asif
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Mahmood, Farhan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Ekstedt, Mathias
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    An Experimental Forensic Test bed: Attack-based Digital Forensic Analysis of WAMPAC Applications2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The global trend is to go digital, in other words go 'smart'. Like the rest of the world getting smarter, so is the power sector hence the term smart power grids and substations. Such capability comes at a price, in this case increasing risk of potential cyber threats to substations. With all such potential risks, it is important that we are able to trace back and attribute any potential threats to its root. In this paper, we're exploring substations to find potential evidences in case a forensic investigation becomes a necessity. Moreover, a forensic experimental test bed is proposed for digital forensic analysis. Finally, a mapping of attack-based forensic evidences is presented.

  • 42.
    Iqbal, Asif
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Mahmood, Farhan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Ekstedt, Mathias
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Digital Forensic Analysis of Industrial Control Systems Using Sandboxing: A Case of WAMPAC Applications in the Power Systems2019Inngår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 12, nr 13, artikkel-id 2598Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In today's connected world, there is a tendency of connectivity even in the sectors which conventionally have been not so connected in the past, such as power systems substations. Substations have seen considerable digitalization of the grid hence, providing much more available insights than before. This has all been possible due to connectivity, digitalization and automation of the power grids. Interestingly, this also means that anybody can access such critical infrastructures from a remote location and gone are the days of physical barriers. The power of connectivity and control makes it a much more challenging task to protect critical industrial control systems. This capability comes at a price, in this case, increasing the risk of potential cyber threats to substations. With all such potential risks, it is important that they can be traced back and attributed to any potential threats to their roots. It is extremely important for a forensic investigation to get credible evidence of any cyber-attack as required by the Daubert standard. Hence, to be able to identify and capture digital artifacts as a result of different attacks, in this paper, the authors have implemented and improvised a forensic testbed by implementing a sandboxing technique in the context of real time-hardware-in-the-loop setup. Newer experiments have been added by emulating the cyber-attacks on WAMPAC applications, and collecting and analyzing captured artifacts. Further, using sandboxing for the first time in such a setup has proven helpful.

  • 43.
    Iqbal, Asif
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Mahmood, Farhan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Shalaginov, Andrii
    Department of Information Security & Communication Technology, Norwegian University of Science and Technology, Norway.
    Ekstedt, Mathias
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Identification of Attack-based Digital Forensic Evidences for WAMPAC Systems2018Inngår i: Proceedings - 2018 IEEE International Conference on Big Data, Big Data 2018, Seattle, Washington, USA: IEEE conference proceedings, 2018, s. 3078-3086, artikkel-id 8622550Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Power systems domain has generally been very conservative in terms of conducting digital forensic investigations, especially so since the advent of smart grids. This lack of research due to a multitude of challenges has resulted in absence of knowledge base and resources to facilitate such an investigation. Digitalization in the form of smart grids is upon us but in case of cyber-attacks, attribution to such attacks is challenging and difficult if not impossible. In this research, we have identified digital forensic artifacts resulting from a cyber-attack on Wide Area Monitoring, Protection and Control (WAMPAC) systems, which will help an investigator attribute an attack using the identified evidences. The research also shows the usage of sandboxing for digital forensics along with hardware-in-the-loop (HIL) setup. This is first of its kind effort to identify and acquire all the digital forensic evidences for WAMPAC systems which will ultimately help in building a body of knowledge and taxonomy for power system forensics.

  • 44.
    Iqbal, Asif
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Shalaginov, Andrii
    Department of Information Security & Communication Technology, Norwegian University of Science and Technology, Norway.
    Mahmood, Farhan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Intelligent analysis of digital evidences in large-scale logs in power systems attributed to the attacks2018Inngår i: Proceedings - 2018 IEEE International Conference on Big Data, Big Data 2018, 2018, s. 3087-3092Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Smart grid improves and revolutionizes the way how energy is generated, distributed and consumed. Despite utilization of such technologies for better life of end-users and communities, there might be outlier events happening that will introduce disturbance to the smart grids. To mitigate impact from such events in power grid, particularly in Wide Area Monitoring Protection and Control (WAMPAC) has been introduced for mitigation and prevention of large disruption and extreme events. Large network of interconnected devices is being monitored through WAMPAC sub-system to avoid major events with negative impact through analysis of system-wide contextual information. The assessment of the state is being made based on the data from Phasor Measurement Unit (PMUs) collected and processed in the Phasor Data Concentrator (PDC). There is an enormous amount of Machine-to-Machine (M2M) communication that the system has to analyze. However, blackout prediction and mitigation is done using measurements data and does not necessarily focus on more high level adversarial events. This paper proposes an ongoing research into timely detection of adversarial attack on the power grid.  During the experimental phase, authentication attack scenario was successfully executed on power substation setup. Further, framework for intelligent identification of digital evidences related to attack was suggested unveiling possibility for crime investigations preparedness.

  • 45.
    Jiang, Xiaolin
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Wireless Communication Networks for Time-critical Industrial Applications2018Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Wireless communication is of paramount importance to enable the vision of Industry 4.0. Compared to mobile communications, industrial communications pose demanding requirements in terms of ultra low latency and high reliability. Currently, for the most time-critical industrial applications, there is no available wireless solutions satisfying these latency requirements. This thesis studies effective techniques to reduce the latency for the time-critical industrial applications, especially from the Physical Layer (PHY) point of view.

    The thesis is organized in two main parts. In the first part, the available methods for low latency are surveyed and analyzed in terms of end-to-end latency. It is argued that the enabling techniques should be optimized together to reduce the end-to-end latency while satisfying other requirements such as reliability and throughput. Moreover, the realistic timing constraints of different PHY algorithms, hardware, and mechanisms are derived based on the state-of-art wireless implementations. In the second part, a revision of PHY with an optimized PHY structure is proposed to reduce the latency. It is shown that a PHY with just a short one-symbol preamble and dedicated packet detection and synchronization algorithms for short packets is robust to carrier frequency offsets and false alarms by both theoretical and site experiments.

    The investigations of this thesis show that revising the PHY structure/parameters is effective to reduce the packet transmission time, and further improve the latency performance of wireless communication network for time-critical industrial applications. In the future, we include the PHY results of this thesis in the investigation of the Medium Access Control (MAC), for industrial wireless communications with very low latencies.

  • 46.
    Jiang, Xiaolin
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Pang, Zhibo
    ABB Corp Res Ctr, Wireless Commun, Vasteras, Sweden..
    Luvisotto, Michele
    ABB Corp Res Ctr, Vasteras, Sweden..
    Pan, Fei
    Univ Elect Sci & Technol China, Natl Key Lab Sci & Technol Commun, Commun & Informat Syst, Chengdu, Sichuan, Peoples R China..
    Candell, Richard
    NIST, Gaithersburg, MD 20899 USA..
    Fischione, Carlos
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik. Synopsys, Mountain View, CA USA.;United Technol Res Ctr, E Hartford, CT 06108 USA..
    Using a Large Data Set to Improve Industrial Wireless Communications Latency, Reliability, and Security2019Inngår i: IEEE Industrial Electronics Magazine, ISSN 1932-4529, E-ISSN 1941-0115, Vol. 13, nr 1, s. 6-12Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Trealize the Industry 4.0 vision and enable mobile connectivity and flexible deployment in harsh industrial environments, wireless communication is essential. But before wireless communications technology can be widely deployed for critical control applications, first it must be assessed, and that requires a comprehensive characterization of the wireless channel. This can be done by analyzing large amounts of wireless data collected from different industrial environments. In this article, we discuss the possibilities offered by a recently published industrial wireless data set. This data set is more exhaustive than measurements previously reported. We show two cases of how those data have been applied to improve latency performance and to investigate the feasibility of physical-layer security techniques for wireless communication in industrial environments.

  • 47.
    Jiang, Xiaolin
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Pang, Zhibo
    ABB Corporate Research, Sweden.
    N. Jansson, Roger
    ABB Corporate Research, Sweden.
    Pan, Fei
    University of Electronic Science and Technology of China, China.
    Fischione, Carlo
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Fundamental Constraints for Time-slotted MAC Design in Wireless High Performance : the Realistic Perspective of Timing2018Konferansepaper (Fagfellevurdert)
  • 48.
    Jiang, Xiaolin
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Pang, Zhibo
    Zhan, Ming
    Dzung, Dacfey
    Luvisotto, Michele
    Fischione, Carlo
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Packet Detection by a Single OFDM Symbol in URLLC for Critical Industrial Control: A Realistic Study2019Inngår i: IEEE Journal on Selected Areas in Communications, ISSN 0733-8716, E-ISSN 1558-0008, Vol. 37, nr 4, s. 933-946Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ultra-high reliable and low-latency communication (URLLC)is envisaged to support emerging applications with strict latency and reliability requirements. Critical industrial control is among the most important URLLC applications where the stringent requirements make the deployment of wireless networks critical, especially as far as latency is concerned. Since the amount of data exchanged in critical industrial communications is generally small, an effective way to reduce the latency is to minimize the packet's synchronization overhead, starting from the physical layer (PHY). This paper proposes to use a short one-symbol PHY preamble for critical wireless industrial communications, reducing significantly the transmission latency with respect to other wireless standards. Dedicated packet detection and synchronization algorithms are discussed, analyzed, and tuned to ensure that the required reliability level is achieved with such extremely short preamble. Theoretical analysis, simulations, and experiments show that detection error rates smaller than 10(-6) can be achieved with the proposed preamble while minimizing the latencies.

  • 49.
    Jiang, Xiaolin
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Pang, Zhibo
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Teknisk informationsvetenskap.
    Zhan, Ming
    KTH.
    Dzung, Dacfey
    Luvisotto, Michele
    Fischione, Carlo
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Packet Detection by Single OFDM Symbol in URLLC for Critical Industrial Control: a Realistic Study2018Inngår i: IEEE Journal on Selected Areas in Communications, ISSN 0733-8716, E-ISSN 1558-0008Artikkel i tidsskrift (Annet vitenskapelig)
  • 50.
    Jiang, Xiaolin
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik. KTH.
    Shokri-Ghadikolaei, Hossein
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Fischione, Carlo
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Nätverk och systemteknik.
    Pang, Zhibo
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    A Simplified Interference Model for Outdoor Millimeter-waveNetworks2019Inngår i: Mobile Networks and Applications, ISSN 1383-469X, Vol. 24, nr 3, s. 983-990Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Industry 4.0 is the emerging trend of the industrial automation. Millimeter-wave (mmWave) communication is a prominent technology for wireless networks to support the Industry 4.0 requirements. The availability of tractable accurate interference models would greatly facilitate performance analysis and protocol development for these networks. In this paper, we investigate the accuracy of an interference model that assumes impenetrable obstacles and neglects the sidelobes. We quantify the error of such a model in terms of statistical distribution of the signal to noise plus interference ratio and of the user rate for outdoor mmWave networks under different carrier frequencies and antenna array settings. The results show that assuming impenetrable obstacle comes at almost no accuracy penalty, and the accuracy of neglecting antenna sidelobes can be guaranteed with sufficiently large number of antenna elements. The comprehensive discussions of this paper provide useful insights for the performance analysis and protocol design of outdoor mmWave networks.

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