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  • 1.
    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.

  • 2.
    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.

  • 3.
    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.

  • 4.
    Atanasovski, Vladimir M.
    et al.
    Faculty of Electrical Engineering, Ss. Cyril and Mehtodius, Skopje.
    van de Beek, Jaap
    Dejonghe, Antoine
    Interuniversity Micro-Electronics Center (IMEC), Leuven.
    Denkovski, Daniel
    Faculty of Electrical Engineering, Ss. Cyril and Mehtodius, Skopje.
    Gravilovska, Liljana M.
    Faculty of Electrical Engineering, Ss. Cyril and Mehtodius, Skopje.
    Grimoud, Sébastien
    Orange Labs, Telecom R and D, Issy-les-Moulineaux.
    Mähönen, Petri H.
    Institute for Networked Systems, RWTH Aachen University.
    Pavloski, Mihajlo
    Faculty of Electrical Engineering, Ss. Cyril and Mehtodius, Skopje.
    Rakovic, Valentin
    Faculty of Electrical Engineering, Ss. Cyril and Mehtodius, Skopje.
    Rihijärvi, Janne
    Institute for Networked Systems, RWTH Aachen University.
    Sayraç, Berna
    Orange Labs., Issy-les-Moulineaux.
    Constructing radio environment maps with heterogeneous spectrum sensors2011In: 2011 IEEE Symposium on New Frontiers in Dynamic Spectrum Access Networks (DySPAN 2011): Aachen, Germany, 3 - 6 May, 2011, Piscataway, NJ: IEEE Communications Society, 2011, p. 660-661, article id 5936266Conference paper (Refereed)
    Abstract [en]

    In this demonstration proposal we describe a prototype of a radio environment map (REM) for storing and reasoning about spectrum data obtained from heterogeneous sources. The architecture of the REM prototype is both modular and extendible, and can be used with very diverse spectrum sensors, ranging from high-fidelity spectrum analyzers to dedicated low-cost embedded solutions. In the proposed demonstration we will illustrate how information such as transmitter locations and estimates of spectrum occupancy over space and time can be inferred and made available through the REM, based on information obtained from a network of different spectrum sensors deployed specifically for the demonstration

  • 5.
    Browne Mwakyanjala, Moses
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. REMOS Space Systems AB, Luleå, Sweden.
    de Oliviera, Élcio Jeronimo
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Validation of a software-defined baseband system for satellite telemetry and telecommand2021In: International Journal of Satellite Communications And Networking, ISSN 1542-0973, E-ISSN 1542-0981, Vol. 39, no 6, p. 605-625Article in journal (Refereed)
    Abstract [en]

    This paper presents the validation of a software-defined baseband (SDB) system for satellite telemetry and telecommand (TM/TC). The baseband system was developed using the open-source GNU Radio development kit. It runs on a personal computer connected to a commercial-off-the-shelf (CoTS) RF frontend. The validation process was performed by the use of a mission-qualified satellite emulator, a state-of-the-art baseband unit, and orbiting satellites. The baseband is designed to offer multimission support. Hence, it includes a suite of modulation schemes, line codes, matched filters, and Consultative Committee for Space Data Systems (CCSDS) forward error correction codes (convolutional, Reed–Solomon, concatenated, and low-density parity-check [LDPC]) typically employed in TM/TC missions. The figures of merit used for the validation of the TM receiver are bit error rate (BER) and frame error rate (FER). For the TC transmitter, the validated features are modulation index, power spectrum, and the physical layer operations procedures (PLOP).

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  • 6.
    Browne Mwakyanjala, Moses
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Functional Analysis of Software-Defined Radio Baseband for Satellite Ground Operations2019In: Journal of Spacecraft and Rockets, ISSN 0022-4650, E-ISSN 1533-6794, Vol. 56, no 2, p. 458-475Article in journal (Refereed)
    Abstract [en]

    This paper presents functional analysis and system specifications of a baseband system using software-defined radio (SDR) technology. The analysis is primarily based on the latest blue-book standards from the Consultative Committee for Space Data Systems (CCSDS). It covers telemetry, telecommand, and ranging, as well as some specifications of the associated physical layers. The SDR-based baseband system is envisioned to support ground operations in the form of a software-as-a-Service (SaaS) private cloud.

  • 7.
    Browne Mwakyanjala, Moses
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Software-defined radio transceiver for QB50 CubeSat telemetry and telecommand2016In: Proceedings of the 34th AIAA International Communications Satellite Systems Conference (ICSSC 2016), American Institute of Aeronautics and Astronautics, 2016Conference paper (Refereed)
    Abstract [en]

    This paper presents the development of a ground system based on software-defined radio for supporting both ground testing and space telemetry and telecommand of one of the nanosatellites in the QB50 mission. The QB50 project is an ongoing European Commission Seventh Framework initiative, which aims at launching a constellation of 50 CubeSats in the lower thermosphere to carry out in-situ scientific measurements. The paper discusses the implementation of amateur radio protocols and telecommunication modulation schemes on the ground system. The system setup, deployment and scheduling are also discussed using two separate ground stations. The use of different software for testing the system is detailed, the results show the operability of the developed ground system. © 2016, American Institute of Aeronautics and Astronautics Inc

  • 8.
    Browne Mwakyanjala, Moses
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Institute for Aerospace Studies, University of Toronto.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Verification of phase and frequency modulation for software-defined radio baseband systems using field data2017In: 35th AIAA International Communications Satellite Systems Conference, ICSSC 2017, American Institute of Aeronautics and Astronautics, 2017, article id 2017-5407Conference paper (Refereed)
    Abstract [en]

    This paper presents the verification of phase and frequency modulation schemes for a software-defined radio baseband system that is being prototyped to support satellite telemetry, telecommand and ranging. It presents the theory behind the two modulation schemes, implementation and verification against emulated signals from a space-qualified hardware-based baseband system as well as from the Odin satellite.

  • 9.
    Browne Mwakyanjala, Moses
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. REMOS Space Systems AB, Norrbotten, Sweden.
    Hyvönen, Petrus
    Satellite Management Services, SSC—Swedish Space Corporation, Solna, Sweden.
    de Oliviera, Élcio Jeronimo
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Feasibility of using a software-defined baseband for multiple space per aperture (MSPA) ground operations2022In: International Journal of Satellite Communications And Networking, ISSN 1542-0973, E-ISSN 1542-0981, Vol. 40, no 2, p. 133-147Article in journal (Refereed)
    Abstract [en]

    This paper presents the feasibility of performing multiple spacecraft per aperture (MSPA) ground operations by using a low-cost software-defined baseband (SDB). The SDB is a Consultative Committee for Space Data Systems (CCSDS)-compliant baseband that employs a personal computer for signal processing and a low-cost commercial-off-the-shelf RF front end for RF signal sampling. The SDB is customized to offer traditional telemetry, tracking, and command (TT&C) services for near-Earth missions operating in S band. The study starts by reviewing MSPA methods already studied by space agencies such as NASA and ESA before going to MSPA methods proposed in the latest CCSDS blue book on RF and modulation systems. The feasibility of operating the CCSDS-proposed multiple uplink carrier MSPA method using the SDB is assessed after evaluating in-band interference and out-of-band emissions from the uplink signals radiated by the low-cost RF front end employed by the SDB. Furthermore, we present a case study where the SDB is used in MSPA operations on a typical solid-state amplifier (SSPA) amplifier typically used in near-Earth missions. 

  • 10.
    Browne Mwakyanjala, Moses
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Nieto‐Peroy, Cristóbal
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Emami, M. Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Concurrent development and verification of an all‐software baseband for satellite ground operations2020In: International Journal of Satellite Communications And Networking, ISSN 1542-0973, E-ISSN 1542-0981, Vol. 38, no 2, p. 209-227Article in journal (Refereed)
    Abstract [en]

    Communication systems are adopting all‐software architectures, because of their scalability, extensibility, flexibility, and cost‐effectiveness. This paper introduces a concurrent approach to the development and verification of baseband systems for satellite ground operations based on the behaviour‐driven development methodology. The open‐source GNU Radio development kit is used for developing the software‐defined radio baseband signal processing, as well as simulating the satellite and realistic channel impairments. The system performance at the end shows deviations of less than 1 dB with respect to the ideal performance and the Green Book standards specified by the Consultative Committee for Space Data Systems.

  • 11.
    Cai, Tao
    et al.
    R & D centre, Huawei Technologies Sweden AB, Kista, Sweden.
    Koudouridis, Georgios P.
    R & D centre, Huawei Technologies Sweden AB, Kista, Sweden.
    Johansson, Johan
    R & D centre, Huawei Technologies Sweden AB, Kista, Sweden.
    van de Beek, Jaap
    R & D centre, Huawei Technologies Sweden AB, Kista, Sweden.
    Nasreddinne, Jad
    Institute for Networked Systems, RWTH Aachen University, Aachen, Germany.
    Petrova, Marina
    Institute for Networked Systems, RWTH Aachen University, Aachen, Germany.
    Mähönen, Petri
    Institute for Networked Systems, RWTH Aachen University, Aachen, Germany.
    An implementation of cognitive resource management on LTE platform2010In: 2010 IEEE 21st International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC 2010): Istanbul, Turkey, 26 - 30 September 2010, Piscataway, NJ: IEEE Communications Society, 2010, p. 2663-2668Conference paper (Refereed)
    Abstract [en]

    In this paper we describe an LTE based demonstrator of the Universal Link Layer API (ULLA) and Cognitive Resource Manager (CRM) modules that are developed in ARAGORN project. The demonstrated LTE system comprises one LTE TDD eNode B and one User Equipment (UE). We first introduce ULLA and CRM framework and then demonstrate their suitability to be implemented with the existing LTE equipments. We show how, through ULLA, CRM is able to obtain PHY/MAC status information of the link between the eNode B and UE, and in turn change system parameters to achieve better resource utilization and transmission efficiency. The control logic can be implemented with simple adaptation or policy-based intelligent methods. The platform clearly shows the feasibility to use ULLA/CRM architecture for radio resource management in a LTE network. It also shows the neutrality of ULLA/CRM mechanisms towards PHY/MAC characteristics of LTE technology platform; hence the platform is viable to flexibly switch between technology platforms (e.g. between LTE access and WiFi access) under the control of ULLA/CRM.

  • 12.
    Cai, Tao
    et al.
    Huawei Technologies Sweden.
    van de Beek, Jaap
    Nasreddinne, Jad
    Institute for Networked Systems, RWTH Aachen University.
    Petrova, Marina M.
    Institute for Networked Systems, RWTH Aachen University.
    Mähönen, Petri H.
    Institute for Networked Systems, RWTH Aachen University.
    A TD-LTE prototype system with modules for general-purpose cognitive resource management and radio-environmental mapping2011In: International Journal of Wireless Information Networks, ISSN 1068-9605, E-ISSN 1572-8129, Vol. 18, no 3, p. 131-145Article in journal (Refereed)
    Abstract [en]

    In this article we describe a demonstrator that shows how the cognitive resource manager (CRM) and the radio-environmental map (REM) can be efficiently implemented in full commercial grade cellular system (i.e., LTE system). The demonstrator shows how the modular CRM together with its open interface, the universal link-layer API (ULLA), facilitates the implementation of efficient radio resource management techniques guaranteeing the quality of service in the LTE system. The CRM, through ULLA, is able to obtain PHY/MAC status information of the link between the tested eNode B and the user equipment, and reconfigure link parameters. This measure-and-control by CRM/ULLA is independent of the underlying radio access technology, which shows the neutrality of CRM/ULLA towards PHY/MAC characteristics. The article also shows how the REM can be easily implemented in such system and how the REM provides the CRM with environmental information that enhances system management performance

  • 13.
    Cai, Tao
    et al.
    Huawei Technologies Sweden.
    van de Beek, Jaap
    Sayraç, Berna
    Orange Labs., Issy-les-Moulineaux.
    Grimoud, Sébastien
    Orange Labs., Issy-les-Moulineaux.
    Nasreddine, Jad
    Institute for Networked Systems, RWTH Aachen University.
    Rihijärvi, Janne
    Institute for Networked Systems, RWTH Aachen University.
    Mähönen, Petri H.
    Institute for Networked Systems, RWTH Aachen University.
    Design of layered radio environment maps for RAN optimization in heterogeneous LTE systems2011In: 2011 IEEE 22nd International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC 2011): Toronto, Ontario, Canada, 11 - 14 September 2011, Piscataway, NJ: IEEE Communications Society, 2011, p. 172-176, article id 6139803Conference paper (Refereed)
    Abstract [en]

    In this contribution a layered radio environment map (REM) architecture is designed and applied in the framework of radio-access network optimization for heterogeneous LTE systems that comprise both macrocells and femtocells. We define layer as the hierarchical representation of a geographical area. In each layer, different instances of the same architectural block will have different spatial/temporal granularities, associated with network functionalities. The effectiveness of the proposed architecture to support LTE functions like automatic neighbor relation (ANR) and minimization of drive tests (MDT) is discussed. In addition, we present the benefits of using such architecture in the implementation of these functions along with its potential to bring performance gains

  • 14.
    Carlson, Johan E.
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Andren, Erik
    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.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Monitoring Changes in Mechanical Properties of Rock Bolts Using a Low-Power Coded-Excitation Scheme2018In: 2018 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IUS), IEEE, 2018, article id 8580038Conference paper (Refereed)
    Abstract [en]

    In-situ inspection and quality assessment of rock bolts and other load-bearing structural elements, has received significant attention over the years, but there are still no techniques available capable of monitoring changes over time in mechanical properties of already installed bolts. Since mechanical changes will also affect the propagation of mechanical waves, ultrasound is a strong candidate. In this paper we propose a technique based on Orthogonal Frequency Division Multiplexing (OFDM) for coding the transmitted ultrasound pulse in such a way that the propagation channel (transducer and rock bolt combined) can be estimated. We show that a transmit voltage of 1.1 V r.m.s. is sufficient to obtain reliable channel estimates even in bolts as long as one meter. The channel estimates are then used to predict changes in tensile stress on the bolt, from experiments conducted in a laboratory environment.

  • 15.
    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.

  • 16.
    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.

  • 17.
    Chiaraviglio, Luca
    et al.
    CNIT, Italy.
    Blefari-Melazzi, Nicola
    CNIT, Italy.
    Liu, William
    AUT, New Zealand.
    Gutierrez, Jairo A.
    AUT, New Zealand.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Birke, Robert
    IBM Research, Switzerland.
    Chen, Lydia
    IBM Research, Switzerland.
    Idzikowski, Filip
    Faculty of Electronics and Telecommunications, Poznan University of Technology.
    Kilper, Daniel
    The University of Arizona.
    Monti, Paolo
    KTH Royal Institute of Technology.
    Wu, Jinsong
    University of Chile.
    5G in rural and low-income areas: Are we ready?2017In: Proceedings of the 8th ITU Kaleidoscope academic conference: ICTs for a Sustainable World, Piscataway, NJ: IEEE Communications Society, 2017, p. 99-106, article id 7805720Conference paper (Refereed)
    Abstract [en]

    Current trends in telecommunication networks foresee the adoption of the,fifth generation (5G) of wireless networks in the near fixture. However; a large number of people are living without coverage and connectivity. To face this issue, we consider the possibility of deploying 5G networks in rural and low-income zones. After detailing the current state-of-the-art, we consider the main challenges that need to be faced. Moreover; we define the main pillars to follow in order to deploy 5G networks in such zones, as well as a proposal of a future network architecture.

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  • 18.
    Chiaraviglio, Luca
    et al.
    Consorzio Nazionale Interuniversitario per le Telecomunicazioni and University of Rome Tor Vergata.
    Blefari-Melazzi, Nicola
    Consorzio Nazionale Interuniversitario per le Telecomunicazioni and University of Rome Tor Vergata.
    Liu, William
    Auckland University of Technology.
    Gutiérrez, Jairo A.
    Auckland University of Technology.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Birke, Robert
    IBM Research, Switzerland.
    Chen, Lydia
    IBM Research.
    Idzikowski, Filip
    Poznan University of Technology.
    Kilper, Daniel
    University of Arizona.
    Monti, Paolo
    KTH Royal Institute of Technology.
    Bagula, Antoine
    University of Western Cape.
    Wu, Jinsong
    University of Chile.
    Bringing 5G into Rural and Low-Income Areas: Is It Feasible?2017In: IEEE Communications Standards Magazine, ISSN 2471-2825, Vol. 1, no 3, p. 50-57Article in journal (Refereed)
    Abstract [en]

    Nowadays, at least two billion people are experiencing a complete lack of wireless cellular network coverage. These users live in rural areas and low-income regions, where network operators are not keen to invest, mainly due to high capital expenditure and operational expenditure costs, as well as the scarcity of electricity from the grid. We tackle this challenge by proposing a 5G network explicitly designed to serve rural and low-income areas. Our solution investigates the possibility of mounting remote radio heads on top of unmanned aerial vehicles, as well as large cells (LCs) to increase the coverage range. In addition, 5G nodes are powered by solar panels and batteries. Preliminary results, obtained over three representative case studies located in Italy, Cook Islands, and Zimbabwe, show that providing connectivity in rural and low-income areas by means of the proposed 5G architecture is feasible. At the same time, we also show that the monthly subscription fee paid by the users can be kept sufficiently low, that is, less than €1/month in low-income areas, and around €11/month in rural regions.

  • 19.
    Edfors, Ove
    et al.
    Luleå University of Technology.
    Sandell, Magnus
    Luleå University of Technology.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Landström, Daniel
    Luleå University of Technology.
    Sjöberg, Frank
    Luleå University of Technology.
    An introduction to orthogonal frequency-division multiplexing1997Report (Other academic)
    Abstract [en]

    This report is an introduction to orthogonal frequency-division multiplexing (OFDM). The focus is on signal processing areas pursued by our research group at Luleå University of Technology. We present an historical background and some frequently used system models. Typical areas of applications are also described, both wireless and wired. In addition to the general overview, the addressed areas include synchronization, channel estimation and channel coding. Both time and frequency synchronization are described, and the effects of synchronization errors are presented. Different types of channel estimators are described, where the focus is on low-complexity algorithms, and in this context, advantages and disadvantages of coherent and differential modulation are also discussed. Channel coding is described, both for wireless and wired systems, and pointers are included to evaluation tools and bitloading algorithms. An extensive bibliography is also included.

  • 20.
    Edfors, Ove
    et al.
    Luleå University of Technology.
    Sandell, Magnus
    Luleå University of Technology.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Landström, Daniel
    Luleå University of Technology.
    Sjöberg, Frank
    Luleå University of Technology.
    An introduction to orthogonal frequency-division multiplexing1997Report (Other academic)
    Abstract [en]

    This report is an introduction to orthogonal frequency-division multiplexing (OFDM). The focus is on signal processing areas pursued by our research group at Luleå University of Technology. We present an historical background and some frequently used system models. Typical areas of applications are also described, both wireless and wired. In addition to the general overview, the addressed areas include synchronization, channel estimation and channel coding. Both time and frequency synchronization are described, and the effects of synchronization errors are presented. Different types of channel estimators are described, where the focus is on low-complexity algorithms, and in this context, advantages and disadvantages of coherent and differential modulation are also discussed. Channel coding is described, both for wireless and wired systems, and pointers are included to evaluation tools and bitloading algorithms. An extensive bibliography is also included.

    Download full text (pdf)
    FULLTEXT01
  • 21.
    Edfors, Ove
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Sandell, Magnus
    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.
    Wilson, Sarah Kate
    Purdue University, USA.
    Börjesson, Per Ola
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    An application of the singular value decomposition to OFDM channel estimation1996In: Proceedings of the 1996 SNRV and NUTEK Conference on Radio Sciences and Telecommunications in Luleå and Kiruna June 3-6, 1996: RVK 96 / [ed] Lars H. Zetterberg, Luleå: Luleå tekniska universitet, 1996, p. 678-682Conference paper (Refereed)
    Abstract [en]

    A new approach to low-complexity channel estimation in orthogonal-frequency division multiplexing (OFDM) systems is described. A low-rank approximation is applied to a linear minimum mean-squared error (LMMSE) estimator that uses the frequency correlation of the channel. By using the singular-value decomposition (SVD) an optimal low-rank estimator is derived, where performance is essentially preserved - even for low computational complexities. A fixed estimator, with nominal values for channel correlation and signal-to-noise ratio (SNR), is analysed. Analytical mean-squared error (MSE) and symbol-error rates (SER) are presented for a 16-QAM OFDM system.

    Download full text (pdf)
    fulltext
  • 22.
    Edfors, Ove
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Sandell, Magnus
    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.
    Wilson, Sarah Kate
    Purdue University, USA.
    Börjesson, Per Ola
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Analysis of DFT-based channel estimators for OFDM1996Report (Other academic)
    Abstract [en]

    In this paper we analyze the performance of three low-complexity channel estimators, based on the discrete Fourier-transform (DFT), for orthogonal frequency-division multiplexing (OFDM) systems. Estimators of this type have been analyzed for discrete-time channels, and we extend this analysis to continuous-time channels. We present analytical expressions for their mean-squared error (MSE) and evaluate their complexity versus symbol-error rate (SER) for 16-QAM. The analysis shows that this type of estimators may experience an irreducible error floor at high SNRs. However, in one of the three estimators the error floor can be eliminated while the complexity stays low and the performance is maximized.

    Download full text (pdf)
    FULLTEXT01
  • 23.
    Edfors, Ove
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Sandell, Magnus
    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.
    Wilson, Sarah Kate
    Purdue University, USA.
    Börjesson, Per Ola
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    OFDM channel estimation by singular value decomposition1996Report (Other academic)
    Abstract [en]

    In this report we present and analyse low-rank channel estimators for orthogonal frequency-division multiplexing (OFDM) using the frequency correlation of the channel. Low-rank approximations based on the discrete Fourier transform (DFT) have been proposed but they suffer from poor performance when the channel is not sample-spaced. We apply the theory of optimal rank-reduction to linear minimum mean-squared error (LMMSE) estimators and show that these estimators, when using a fixed design, are robust to changes in channel correlation and signal-to-noise ratio (SNR). The performance is presented in terms of uncoded symbol-error rate (SER) for a system using 16-QAM.

    Download full text (pdf)
    FULLTEXT01
  • 24.
    Edfors, Ove
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Sandell, Magnus
    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.
    Wilson, Sarah Kate
    School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA.
    Börjesson, Per Ola
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    OFDM channel estimation by singular value decomposition1996In: Mobile technology for the human race: 1996 IEEE 46th Vehicular Technology Conference, Atlanta, Georgia, USA, April 28 - May 1, 1996 / [ed] Jim Worsham, Piscataway, NJ: IEEE Communications Society, 1996, p. 923-927Conference paper (Refereed)
    Abstract [en]

    A new approach to low-complexity channel estimation in orthogonal-frequency division multiplexing (OFDM) systems is proposed. A low-rank approximation is applied to a linear minimum mean-squared error (LMMSE) estimator that uses the frequency correlation of the channel. By using the singular-value decomposition (SVD) an optimal low-rank estimator is derived, where performance is essentially preserved - even for low computational complexities. A fixed estimator, with nominal values for channel correlation and signal-to-noise ratio (SNR), is analysed. Analytical mean-squared error (MSE) and symbol-error rates (SER) are presented for a 16-QAM OFDM system.

    Download full text (pdf)
    fulltext
  • 25.
    Edfors, Ove
    et al.
    Department of Applied Electronics, Lund University, Lund, Sweden.
    Sandell, Magnus
    Bell Labs, Lucent Technologies, Swindon, U.K..
    van de Beek, Jan-Jaap
    Nokia Svenska AB, R&D, Kista, Sweden.
    Wilson, Sarah Kate
    Luleå University of Technology.
    Börjesson, Per Ola
    Department of Applied Electronics, Lund University, Lund, Sweden.
    Analysis of DFT-Based Channel Estimators for OFDM2000In: Wireless personal communications, ISSN 0929-6212, E-ISSN 1572-834X, Vol. 12, no 1, p. 55-70Article in journal (Refereed)
    Abstract [en]

    In this paper we analyze the performance of three low-complexity channel estimators, based on the discrete Fourier transform (DFT), for orthogonal frequency-division multiplexing (OFDM) systems. Estimators of this type have been analyzed for discrete-time channels, and we extend this analysis to continuous-time channels. We present analytical expressions for their mean-squared error (MSE) and evaluate their complexity vs. symbol-error rate (SER) for 16-QAM. The analysis shows that this type of estimators may experience an irreducible error floor at high SNRs. However, in one of the three estimators the error floor can be eliminated while the complexity stays low and the performance is maximized.

  • 26.
    Edfors, Ove
    et al.
    Department of Applied Electronics, Lund University, Lund, Sweden.
    Sandell, Magnus
    Bell Laboratories, Lucent Technologies Inc., Swindon, UK.
    van de Beek, Jan-Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Wilson, Sarah Kate
    Luleå University of Technology.
    Börjesson, Per-Ola
    Luleå University of Technology.
    OFDM channel estimation by singular value decomposition1998In: IEEE Transactions on Communications, ISSN 0090-6778, E-ISSN 1558-0857, Vol. 46, no 7, p. 931-939Article in journal (Refereed)
    Abstract [en]

    We present and analyze low-rank channel estimators for orthogonal frequency-division multiplexing (OFDM) systems using the frequency correlation of the channel. Low-rank approximations based on the discrete Fourier transform (DFT) have been proposed, but these suffer from poor performance when the channel is not sample spaced. We apply the theory of optimal rank-reduction to linear minimum mean-squared error (LMMSE) estimators and show that these estimators, when using a fixed design, are robust to changes in channel correlation and signal-to-noise ratio (SNR). The performance is presented in terms of uncoded symbol-error rate (SER) for a system using 16-quadrature amplitude modulation (QAM).

    Download full text (pdf)
    fulltext
  • 27.
    Elfvelin, Martin
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Lorentzson, Gabriel
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Sanchez, Gabriel
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Nieto Peroy, Cristóbal
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Golemis, Aris
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Laufer, René
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Enell, Carl-Fredrik
    EISCAT Scientific Association, Bengt Hultqvistsväg 1, 981 92 Kiruna, Sweden.
    Browne Mwakyanjala, Moses
    Remos Space Systems AB, Aurorum 1C, 977 75, Luleå, Sweden.
    A flexible ground segment for small satellite operations2021In: IAC 2021 Congress Proceedings, 72nd International Astronautical Congress (IAC), Dubai, United Arab Emirates, International Astronautical Federation (IAF) , 2021, article id 65716Conference paper (Refereed)
    Abstract [en]

    With the launch of the first CubeSat a trend of easy access to Low Earth Orbit was started. Today many educational institutes around the world design, build and operate CubeSats for educational as well as scientific purposes. This paper presents designs and development in hardware and software made to achieve a flexible ground segment at the Luleå University of Technology Space Campus in Kiruna, Sweden. The existing ground station is adapted to support more frequencies and modes of operation to enable future satellite projects at the university easy access to space communications. New equipment has been procured and integrated with existing equipment in a new location using a 19-inch server rack. The article presents a ground segment design using software-defined radio to promote flexibility and adaptability. A in-house developed sequence control board is presented that enables the ground station to quickly switch between full duplex and half-duplex modes.

  • 28.
    Eriksson, Mats
    et al.
    Arctos Labs Scandinavia AB.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Rural 5G: Oxymoron or Opportunity?2015In: IEEE ComSoc Technology News, no NovemberArticle in journal (Other (popular science, discussion, etc.))
  • 29.
    Gavrilovska, Liljana M.
    et al.
    Ss. Cyril and Methodius University, Skopje.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Xie, Yong
    Huawei Technologies, Chengdu.
    Lidström, Erik
    Huawei Technologies, Stockholm.
    Riihijärvi, Janne
    RWTH Aachen University.
    Mähönen, Petri H.
    RWTH Aachen University.
    Atanasovski, Vladimir M.
    Ss. Cyril and Methodius University, Skopje, Faculty of Electrical Engineering, Ss. Cyril and Mehtodius, Skopje.
    Denkovski, Daniel
    Faculty of Electrical Engineering, Ss. Cyril and Mehtodius, Skopje.
    Rakovic, Valentin
    Faculty of Electrical Engineering, Ss. Cyril and Mehtodius, Skopje.
    Enabling LTE in TVWS with radio environment maps: From an architecture design towards a system level prototype2014In: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 53, p. 62-72Article in journal (Refereed)
    Abstract [en]

    This paper reports recent prototyping efforts that show the feasibility of the radio environmental map to enable efficient exploitation of TV white spaces by a cellular LTE system. We describe a flexible REM backend implementation, fully integrated with standard-compliant operational LTE base station equipment. Simulations results indicate that REMs enhance white-space detection by their means to incorporate accurate and local channel propagation information, while experimental laboratory results illustrate the feasibility and performance of transmitter localization capabilities in a REM.

  • 30.
    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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  • 31.
    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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  • 32.
    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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    fulltext
  • 33.
    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.
    On the Position of Intelligent Reflecting Surfaces2021In: 2021 Joint European Conference on Networks and Communications & 6G Summit (EuCNC/6G Summit), IEEE, 2021, p. 66-71Conference paper (Refereed)
    Abstract [en]

    We study the positional impact of an intelligent reflecting surface (IRS) on the achievable rate for single and multiple antenna systems. We show that in IRS-aided single antenna systems, it is always best to place the IRS as close as possible to the transmitter or receiver since the large-scale fading for IRS-reflected links is the main factor that characterizes the performance gain. However, for IRS-aided multiple antenna systems, the propagation environment has an important role in characterizing the efficient regions of IRS placement. In the case of a line-of-sight environment, the channel matrix turns out to be rank-deficient. Thus, both far and near IRS placements result in significant achievable rate improvements where the former provides a substantial additional degree-of-freedom, while the latter results in a power gain. Furthermore, as the wireless channel becomes richer with multipath, the rank of the channel matrix increases. Thus, the efficient far placement regions gradually shrink until they disappear in the case of a Rayleigh fading channel where IRS near placements become more efficient than far placements as they result in higher power gains.

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  • 34.
    Idzikowski, Filip
    et al.
    Poznan University of Technology, Faculty of Electronics and Telecommunications.
    Chiaraviglio, Luca
    University of Rome Tor Vergata.
    Liu, William
    Auckland University of Technology.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Future internet architectures and sustainability: An overview2018Conference paper (Refereed)
    Abstract [en]

    The Internet Protocol (IP) traffic is constantly growing. The annual global IP traffic is estimated to reach 2.3 Zettabyte per year by 2020 according to the recent Cisco forecasts. New Internet infrastructures are required to handle the emerging Big Data. Several pilot initiatives have proposed Future Internet (FI) architectures. We provide an overview of the FI architectures from the perspective of sustainable development.

  • 35.
    Landström, Anders
    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.
    Transmitter Localization for 5G mmWave REMs by Stochastic Generalized Triangulation2016In: 23rd International Conference on Telecommunications (ICT 2016), Piscataway, NJ: IEEE Communications Society, 2016, p. 789-793, article id 7500413Conference paper (Refereed)
    Abstract [en]

    Future mobile networks will need new tools to deal with the challenges of emerging technologies. In particular, more flexible networks will require localization of transmitters in the networks. In this work we present a novel method for transmitter localization, suitable for rich multipath mmWave 5G scenarios such as dense urban environments. Our work combines stochastic estimation of Radio Environmental Maps (REMs) with the well known concept of triangulation, generalizing the latter into a method for localization in anisotropic propagation environments. It can be considered a conceptual bridge from classical distance-based triangulation into a generalized version where the propagation environment is taken into account. The result is a highly flexible tool for network planning in general and transmitter localization in particular.

  • 36.
    Landström, Anders
    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.
    Simonsson, Arne
    Ericsson Research AB, Sweden.
    Thurfjell, Magnus
    Ericsson Research AB, Sweden.
    Ökvist, Peter
    Ericsson Research AB, Sweden.
    Measurement-Based Stochastical mmWave Channel Modeling2016In: 2016 IEEE Globecom Workshops (GC Wkshps), Piscataway, NJ: IEEE Communications Society, 2016, article id 7848959Conference paper (Refereed)
    Abstract [en]

    Emerging mmWave technology will require newchannel models. Compared to the lower frequency bands,mmWaves will be more reflected and absorbed but less diffracted.Hence, placement of individual physical structures in the en-vironment will affect the propagation much more than before,providing a challenge for channel modeling. At the same time,however, an increasing amount of information about the topologyof the physical environment, in particular for buildings, is madeavailable through better measurement equipment and servicesfor obtaining 3D data. We propose a Monte-Carlo approachfor channel modeling where interactions between mmWaves andthe surrounding small-scale environment can be included, givena stochastic representation. This method is not only suitablefor assessment of basic effects such as material reflection andabsorption, but can also in the future be extended to variousadditional effects such as weather, traffic, foliage, etc. Theframework is verified against 15 GHz measurements from anurban environment, demonstrating how major reflection pathscan be replicated by modeling the closest buildings.IndexTerms

  • 37.
    Landström, Daniel
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems. Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Distance- Spanning Technology.
    Arenas, Julia Martinez
    Ecole National Supérieure de Télecommunications, Site de Toulouse, Toulouse, France.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems. Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Distance- Spanning Technology.
    Börjesson, Per Ola
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems. Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Distance- Spanning Technology.
    Boucheret, Marie-Laure
    Ecole National Supérieure de Télecommunications, Site de Toulouse, Toulouse, France.
    Ödling, Per
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems. Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Distance- Spanning Technology.
    Time and frequency offset estimation in OFDM systems employing pulse shaping1997In: Bridging the way to the 21st century: 1997 IEEE 6th International Conference on Universal Personal Communications record ; 12 - 16 October 1997, Hotel Del Coronado, San Diego, CA, USA ; conference record, Piscataway, NJ: IEEE Communications Society, 1997, p. 279-283Conference paper (Refereed)
    Abstract [en]

    Time and frequency offset estimation is addressed in an OFDM system that uses a cyclic prefix and pulse shaping. Earlier work has presented a method that avoids the use of pilots by exploiting the inherent correlation in the cyclically extended OFDM symbol. In this paper this technique is extended to include systems with pulse shaping. The joint Maximum Likelihood estimator of time and frequency offsets for such systems is presented and evaluated. An implementable structure of the extended estimator is given. Simulations show that it is possible to maintain the performance when introducing pulse shaping into an OFDM system.

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  • 38.
    Landström, Daniel
    et al.
    Lund University, Dept. of Applied Electronics, SE-221 00 Lund, Sweden.
    Wilson, Sarah Kate
    Luleå University of Technology.
    van de Beek, Jaap
    Nokia Svenska AB, Box 1070, SE-164 25 Kista, Sweden.
    Ödling, Per
    Lund University, Dept. of Applied Electronics, SE-221 00 Lund, Sweden.
    Börjesson, Per Ola
    Lund University, Dept. of Applied Electronics, SE-221 00 Lund, Sweden.
    Symbol time offset estimation in coherent OFDM systems1999In: IEEE International Conference on Communications: ICC '99, Piscataway, NJ: IEEE Communications Society, 1999, Vol. 1, p. 500-505Conference paper (Refereed)
    Abstract [en]

    This paper presents a symbol time offset estimator for coherent OFDM systems. This estimator exploits both the redundancy in the cyclic prefix and the pilot symbols used for channel estimation. The estimator is robust against frequency offsets and is suitable for use in dispersive channels. We base the estimator on the ML estimator for the AWGN channel. Simulations of an example system indicate a system performance as close as 0.3 dB to a perfectly synchronized system. Compared to an estimator not using pilots, our estimator's performance could allow a shorter cyclic prefix and thus a more spectrally efficient system.

  • 39.
    Landström, Daniel
    et al.
    Luleå University of Technology. Lund Institute of Technology, Lund University, Sweden.
    Ödling, Per
    Department of Applied Electronics, Lund University.
    Börjesson, Per Ola
    Luleå University of Technology. Lunds universitet, Lund Institute of Technology, Department of Applied Electronics.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Uplink OFDM synchronization of future multiuser radio systems1999In: Proceedings of radiovetenskap och kommunikation: Karlskrona 14-17 juni 1999 / RVK 99 / [ed] Jan-Olof Gustafsson, Karlskrona: Högskolan i Karlskrona/Ronneby , 1999Conference paper (Refereed)
  • 40.
    Lindberg, Johanna
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Digital Services and Systems.
    Trojer, Elmar
    Ericsson Research.
    Jobér, Johan
    Netmore.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Tiger, Jonas
    IT Norrbotten.
    Value chains, operator sharing models, and regulatory aspects2020Report (Other academic)
  • 41.
    Martinez Arenas, Julia
    et al.
    Ecole National Superieure de Telecommunications, Site de Toulouse.
    Landström, Daniel
    Luleå University of Technology. Lund Institute of Technology, Lund University, Sweden.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Börjesson, Per Ola
    Lund Institute of Technology, Department of Applied Electronics.
    Boucheret, Marie-Laure
    Ecole Nationale Supérieure des Télécommunications.
    Ödling, Per
    Department of Electrosciences, Lund Institute of Technology.
    Synchronization in OFDM systems: Sensitivity to the choice of pulse shape1997Conference paper (Refereed)
  • 42.
    Mohamad, Medhat
    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.
    A Novel Transmitter Architecture for Spectrally-Precoded OFDM2018In: IEEE Transactions on Circuits and Systems Part 1: Regular Papers, ISSN 1549-8328, E-ISSN 1558-0806, Vol. 65, no 8, p. 2592-2605Article in journal (Refereed)
    Abstract [en]

    Frequency nulling spectral precoding is an approachthat suppresses the out-of-band emission in OFDM systems.In this paper, we discuss the transmitter architecture of thespectrally precoded OFDM systems. We design a novel precoderthat matches the practical implementation of the OFDM modulator.We show that spectral precoding can relax the analog lowpass filtering requirements of the OFDM system transmitter. Weexamine the effect of spectral precoding on the PAPR as wellas the effect of the PA on the spectral precoding suppressionperformance. We also study the compliance of the spectrallyprecoded OFDM transmitter with the 3GPP standardizationmeasures and analyze its computation complexity. At the receiverside, we analyze the in-band interference and BER performanceof the suggested precoding approach.

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  • 43.
    Mohamad, Medhat
    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.
    An analysis of out-of-band emission and in-band interference for precoded and classical OFDM systems2015In: European Wireless 2015: 21th European Wireless Conference, 20-22 May 2015, Budapest, Hungary, Piscataway, NJ: IEEE Communications Society, 2015, article id 7147703Conference paper (Refereed)
    Abstract [en]

    In this paper we present analytical expressions for the out-of-band (OOB) emission and in-band interference of two different OOB suppressed OFDM-systems; classical low-pass filtered and precoded. Then, we analytically compare their performance in terms of OOB emission suppression and introduced level of in-band interference. We analyse the fact that the in-band interference introduced by the filter depends on the length of the cyclic prefix as well as the behavior of the channel while that of the precoded OFDM does not. The analysis confirms that edged subcarriers suffer higher in-band interference than central subcarriers. Moreover, frequency precoders, for a specific choice of notching frequencies, can outperform time precoders.

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  • 44.
    Mohamad, Medhat
    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.
    An SDR-based prototype of spectrally-precoded OFDM2017In: EuCNC 2017: European Conference on Networks and Communications, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2017, article id 7980758Conference paper (Refereed)
    Abstract [en]

    Spectrally precoded OFDM is a recent approach that aims for the suppression of the OOB, as well as the in-band gap, emissions in OFDM systems. Theoretically, the technique shows High suppression of the OOB and the in-band gap emissions. Although, practically hardware impairments may limit the precoder's performance. Yet, this demonstration shows that despite the hardware impairments, implemented spectrally precoded OFDM generates emissions tens of decibels less than that of plain OFDM. Therefore, the demonstration proves that communications links are less vulnerable to interference coming from spectrally precoded OFDM signals than to interference coming from plain OFDM signals

  • 45.
    Mohamad, Medhat
    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.
    Minimum-EVM N-continuous OFDM2016In: 2016 IEEE International Conference on Communications (ICC): Kuala Lumpur, 22-27 May 2016, Piscataway, NJ: IEEE Communications Society, 2016, article id 7511164Conference paper (Refereed)
    Abstract [en]

    The N-continuous precoder for the suppression ofOOB emission in OFDM systems that minimizes the EVM isintroduced. We show that the minimum in-band interference dueto the introduced precoding approach is 3 dB less than the inbandinterference of existing N-continuous precoders. Moreover,we introduce a novel practical block precoder that approachesthe performance of the suggested optimal precoder. We analyzethe spectrum of the OFDM signal after block precoding, the inbandinterference due to block precoding and the effect of blockprecoding on the BER. The price to pay for block precoding isthe computational complexity that grows linearly with the blocksize.

  • 46.
    Mohamad, Medhat
    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.
    N-smooth OFDMIn: Article in journal (Refereed)
    Abstract [en]

    This paper introduces a new multicarrier system - a practical alternative for N-continuous OFDM: N-smooth OFDM. N-smooth OFDM improves the spectral compactness of practical OFDM systems by suppressing OOB emission. The higher spectral compactness of N-smooth OFDM allows the system to relax requirements of the digital to analog converter (DAC) construction filter. Moreover, it decreases the signal's self interference that results from spectral precoding as well as precoder's computational complexity. 

  • 47.
    Mohamad, Medhat
    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.
    Spectrally-Precoded OFDM for 5G Wideband Operation in Fragmented sub-6GHz SpectrumArticle in journal (Refereed)
    Abstract [en]

    We consider spectrally-precoded OFDM waveforms for 5G wideband transmission in sub-6GHz band. In this densely

    packed spectrum, a low out-of-band (OOB) waveform is a critical 5G component to achieve the promised high spectral

    efficiency. By precoding data symbols before OFDM modulation, it is possible to achieve extremely low out-of-band

    emission with very sharp spectrum transition enabling an efficient and flexible usage of frequency resources. Spectrallyprecoded

    OFDM shows promising results for reaching 5G targets in high-data rate enhanced mobile broadband and ultrareliable

    low-latency communications use cases. Spectral precoding is particularly efficient for wideband transmission

    enabling short-time transmission, which will often require flexible fragmented spectrum usage.

  • 48.
    Mohamad, Medhat
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Taheri, Tayebeh
    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.
    Subspace-precoded OFDM with low Out-of-Band Emissions:it will workManuscript (preprint) (Other academic)
    Abstract [en]

    Today’s multicarrier transmitters, deployed in essentially all communications radio equipment we use(phones, TV’s, computers, etc.), contain means to avoid undesired out-of-band power emissions. Standards and regulations typically restrict the levels of these emissions in order to allow for an efficient use of the radio spectrum. Radio vendors deploy well-established algorithms such as low-pass filtering or windowing to satisfy these regulations. A new approach, specifically applicable to OFDM systems, known as spectralprecoding, has been studied during the last decade. In particular, subspace precoding has attracted theinterest of academia, for its elegance, and despite a few adamant disadvantages. Recent advances now provide a breakthrough: subspace precoding is now a viable alternative to today’s algorithms.

  • 49.
    Mwakyanjala, Moses B.
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Emami, Reza
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. University of Toronto.
    van de Beek, Jaap
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Software-defined radio baseband system for satellite management services2017In: AIAA SPACE and Astronautics Forum and Exposition, Aerospace Research Central (ARC) , 2017, article id 2017-5244Conference paper (Refereed)
    Abstract [en]

    This paper presents functional analysis and system specifications of a baseband system based on software-defined radio (SDR) technology. The analysis is primarily based on the latest blue-book standards from the Consultative Committee for Space Data Systems(CCSDS). It covers telemetry, telecommand, ranging, and Doppler measurements, as well as some specifications of the associated physical layers. The SDR-based baseband system can support satellite management in the form of a software-as-a-service (SaaS) private cloud.

  • 50.
    Nilsson, Rickard
    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.
    Channel measurements in an open-pit mine using USRPs: 5G-Expect the unexpected2016In: 2016 IEEE Wireless Communications and Networking Conference: WCNC 2016, Doha, Qatar, 3-7  April 2016, 2016, p. 212-217, article id 7564672Conference paper (Refereed)
    Abstract [en]

    In this paper, we describe and analyze the results of a radio channel measurement campaign in an extreme industrial environment; a large open-pit copper mine targeted by next generation’s highly voiced device communications. We present a practical and efficient method to perform robust and high-sensitivity impulse response measurements without a common clock reference using the widely spread USRP hardware. With this technique, we performed channel sounding on a large number of locations within the mine. One important observation is that the radio channel’s impulse response in an open-pit mine can often be more than 10 microseconds long, and much unlike the responses normally associated with Wi-Fi and mobile cellular radio systems, which poses serious design challenges for future 5G radio systems.

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    fulltext
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