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  • 1.
    Allison, R.S.
    et al.
    York University, Canada.
    Brunnström, Kjell
    RISE - Research Institutes of Sweden (2017-2019), ICT, Acreo.
    Chandler, D.M.
    Shizuoka University, Japan.
    Colett, H.
    Intel Corp, USA.
    Corriveau, P.
    Intel Corp, USA.
    Daly, S.
    Dolby Laboratories Inc, USA.
    Goel, J.
    Qualcomm Technologies, USA.
    Long, J.Y.
    Intel Corp, USA.
    Wilcox, L.M.
    York University, Canada.
    Yaacob, Y.
    Shizuoka University, Japan.
    Yang, S. N.
    Pacific University, USA.
    Zhang, Y.
    Xi’an Jiaotong University, China.
    Perspectives on the definition of visually lossless quality for mobile and large format displays2018In: Journal of Electronic Imaging, ISSN 10179909, Vol. 27, no 5, article id 053035Article in journal (Refereed)
    Abstract [en]

    Advances in imaging and display engineering have given rise to new and improved image and videoapplications that aim to maximize visual quality under given resource constraints (e.g., power, bandwidth).Because the human visual system is an imperfect sensor, the images/videos can be represented in a mathematicallylossy fashion but with enough fidelity that the losses are visually imperceptible—commonly termed“visually lossless.” Although a great deal of research has focused on gaining a better understanding ofthe limits of human vision when viewing natural images/video, a universally or even largely accepted definitionof visually lossless remains elusive. Differences in testing methodologies, research objectives, and targetapplications have led to multiple ad-hoc definitions that are often difficult to compare to or otherwise employ inother settings. We present a compendium of technical experiments relating to both vision science and visualquality testing that together explore the research and business perspectives of visually lossless image quality,as well as review recent scientific advances. Together, the studies presented in this paper suggest that a singledefinition of visually lossless quality might not be appropriate; rather, a better goal would be to establish varyinglevels of visually lossless quality that can be quantified in terms of the testing paradigm.

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  • 2.
    Anders, Berntson
    et al.
    Chalmers University of Technology, Sweden.
    Anderson, D.
    Chalmers University of Technology, Sweden.
    Doran, N. J.
    Chalmers University of Technology, Sweden.
    Forysiak, W.
    Chalmers University of Technology, Sweden.
    Nijhof, J. H. B.
    Chalmers University of Technology, Sweden.
    Power dependence and accessible bandwidth for dispersion-managed solitons in asymmetric dispersion maps1998Report (Other academic)
    Abstract [en]

    We investigate how the parameters of dispersion managed solitons depend on the asymmetry of the dispersion map. Using the variational approach and numerical simulations we show that asymmetric maps can increase the accessible bandwidth in the normal average dispersion regime and equalise the power in adjacent WDM channels.

  • 3.
    Anders, Berntson
    et al.
    Chalmers University of Technology, Sweden.
    Anderson, D.
    Chalmers University of Technology, Sweden.
    Doran, N. J.
    Aston University, UK.
    Forysiak, W.
    Aston University, UK.
    Nijhof, J. H. B.
    Aston University, UK.
    Power dependence and accessible bandwidth for dispersion-managed solitons in asymmetric dispersion maps1998In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 34, no 21, p. 2054-2056Article in journal (Refereed)
    Abstract [en]

    The authors investigate how the parameters of dispersion managed solitons depend on the asymmetry of the dispersion map. Using the variational approach and numerical simulations it is shown that asymmetric maps can increase the accessible bandwidth in the normal average dispersion regime and equalise the power in adjacent WDM channels.

  • 4.
    Anders, Berntson
    et al.
    Chalmers University of Technology, Sweden.
    Anderson, D.
    Chalmers University of Technology, Sweden.
    Lisak, M.
    Chalmers University of Technology, Sweden.
    Quiroga-Teixeiro, M. L.
    Chalmers University of Technology, Sweden.
    Karlsson, M.
    Chalmers University of Technology, Sweden.
    Self-phase modulation in dispersion compensated optical fibre transmission systems1996In: Optics Communications, ISSN 0030-4018, E-ISSN 1873-0310, Vol. 130, no 1-3, p. 153-162Article in journal (Refereed)
    Abstract [en]

    An analysis is made of the influence of self-phase modulation on optical fibre communication systems where the chromatic dispersion is compensated for by a dispersion compensation fibre. In particular we derive a simple and useful expression for the optimal fibre length in the presence of nonlinearities.

  • 5.
    Anders, Berntson
    et al.
    Chalmers University of Technology, Sweden.
    Anderson, Dan
    Chalmers University of Technology, Sweden.
    Lisak, Mietek
    Chalmers University of Technology, Sweden.
    Quiroga-Teixeiro, Manuel L.
    Chalmers University of Technology, Sweden.
    Karlsson, Magnus
    Chalmers University of Technology, Sweden.
    Self-phase modulation in dispersion compensated optical fibre transmission systems1998Report (Other academic)
    Abstract [en]

    An analysis is made of the influence of self-phase modulation on optical fibre communication systems where the chromatic dispersion is compensated for by a dispersion compensation fibre. In particular we derive a simple and useful expression for the optimal fibre length in the presence of nonlinearities.

  • 6.
    Anders, Berntson
    et al.
    Chalmers Univ of Technology, Sweden.
    Anderson, Dan
    Chalmers Univ of Technology, Sweden.
    Lisak, Mietek
    Chalmers Univ of Technology, Sweden.
    Teixeiro, Manuel L.Quiroga
    Chalmers Univ of Technology, Sweden.
    Karlsson, Magnus
    Chalmers Univ of Technology, Sweden.
    Self-phase modulation in dispersion-compensating systems1996In: Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS, IEEE , 1996, p. 405-406Conference paper (Refereed)
    Abstract [en]

    The effects of SPM in a dispersion-compensation system are investigated. An explicit and compact formula is presented for the optimal length of the DCF. In particular, it is shown that the order of the fibers is important when SPM is considered. Using precompensation SPM effects can improve system performance. A qualitative comparison between the analytical predictions and previously presented experimental results show good agreement.

  • 7.
    Anders, Berntson
    et al.
    Chalmers University of Technology, Sweden.
    Malomed, B. A.
    Tel Aviv University, Israel.
    Dispersion management with filtering1999In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 24, no 8, p. 507-509Article in journal (Refereed)
    Abstract [en]

    With regards to their potential to improving the pulse-based regimes in optical communication networks, dispersion-managed solitons in a fiber link including guiding filters and compensating gain were investigated. Combining the variational approximation and the perturbative treatment of the filtering and gain, stationary regimes are predicted. Among other features, the minimum map strength necessary for the existence of the pulses when path-averaged dispersion (PAD) is zero or normal is absent, rather, a minimum necessary normalized power for any PAD exists.

  • 8.
    Anders, Berntson
    et al.
    Ericsson Telecom, Sweden.
    Martensson, J.
    Ericsson Telecom, Sweden.
    Westlund, M.
    Ericsson Telecom, Sweden.
    Influence of pulse width and dispersion period on 40 Gbit/s dispersion-managed RZ transmission2000In: Conference on Lasers and Electro-Optics (CLEO 2000)Article in journal (Refereed)
    Abstract [en]

    An overview is given on the numerical investigation of the influence of the dispersion period and the pulse width on the performance of a dispersion-managed (DM) transmission link. Results from studying a transmission link of alternating pieces of standard fiber (SF) and dispersion compensating fiber (DCF) are discussed.

  • 9.
    Anders, Berntson
    et al.
    Ericsson Telecom AB, Sweden.
    Popov, S.
    Ericsson Telecom AB, Sweden.
    Vanin, E.
    Ericsson Telecom AB, Sweden.
    Jacobsen, G.
    Ericsson Telecom AB, Sweden.
    Karlsson, J.
    Ericsson Telecom AB, Sweden.
    Polarisation dependence and gain tilt of Raman amplifiers for WDM systems2001In: Conference on Optical Fiber Communication, Technical Digest Series, 2001, no 1, p. MI2/1-MI2/3Conference paper (Refereed)
    Abstract [en]

    We investigate the polarisation dependence and gain tilt of Raman amplifiers for WDM systems. We find no polarisation dependence of the gain for backward propagating pumps. Results from experiments on commercial 32-channel WDM system are presented, highlighting the effect of gain tilt and pump depletion.

  • 10. Andersson, L. I.
    et al.
    Hedekvist, P. O.
    Rudberg, B. G. R.
    Djupsjöbacka, Anders
    Ericsson, Sweden.
    Andrekson, P. A.
    10 Gb/s Optical Transmission using a Silicon Bipolar Chipset1995In: IEEE/LEOS 1995 Digest of the LEOS Summer Topical Meetings. Flat Panel Display Technology, 1995, p. 59-60Conference paper (Refereed)
    Abstract [en]

    A 10 Gb/s silicon chip set including a 8:1 MUX, a 1.8 DMUX, a dynamic divider, and circuits for clock recovery is described. Results from optical transmission experiments utilizing dispersion compensation techniques such as prechirp and MSSI, and bridging distances from 50 to 100 km, will be presented.

  • 11.
    Behravesh, Rasoul
    et al.
    University of Bologna, Italy.
    Harutyunyan, Davit
    Robert Bosch GmbH, Germany.
    Coronado, Estefania
    I2CAT Foundation, Spain.
    Riggio, Roberto
    RISE Research Institutes of Sweden, Digital Systems, Data Science.
    Time-Sensitive Mobile User Association and SFC Placement in MEC-Enabled 5G Networks2021In: IEEE Transactions on Network and Service Management, ISSN 1932-4537, E-ISSN 1932-4537, Vol. 18, no 3, p. 3006-3020Article in journal (Refereed)
    Abstract [en]

    The ongoing roll-out of 5G networks paves the way for many fascinating applications such as virtual reality (VR), augmented reality (AR), and autonomous driving. Moreover, 5G enables billions of devices to transfer an unprecedented amount of data at the same time. This transformation calls for novel technologies like multi-access edge computing (MEC) to satisfy the stringent latency and bitrate requirements of the mentioned applications. The main challenge pertaining to MEC is that the edge MEC nodes are usually characterized by scarce computational resources compared to the core or cloud, arising the challenge of efficiently utilizing the edge resources while ensuring that the service requirements are satisfied. When considered with the users’ mobility, this poses another challenge, which lies in minimization of the service interruption for the users whose service requests are represented as service function chains (SFCs) composed of virtualized network functions (VNFs) instantiated on the MEC nodes or on the cloud. In this paper, we study the problem of joint user association, SFC placement, and resource allocation, employing mixed-integer linear programming (MILP) techniques. The objective function of this MILP-based problem formulation are to minimize (i) the service provisioning cost, (ii) the transport network utilization, and (iii) the service interruption. Moreover, a heuristic algorithm is proposed to tackle the scalability issue of the MILP-based algorithms. Finally, comprehensive experiments are performed to draw a comparison between these approaches.

  • 12.
    Bosse, Sebastian
    et al.
    Fraunhofer, Germany.
    Brunnström, Kjell
    RISE - Research Institutes of Sweden (2017-2019), ICT, Acreo. Mid Sweden University, Sweden.
    Arndt, Sebastian
    NTNU Norwegian University of Science and Technology, Norway.
    Martini, Maria G.
    Kingston University, UK.
    Ramzan, Naeem
    University of the West of Scotland, UK.
    Engelke, Ulrich
    CSIRO, Australia.
    A common framework for the evaluation of psychophysiological visualquality assessment2019In: Quality and User Experience, ISSN 2366-0139, E-ISSN 2366-0147, Vol. 4, no 3Article in journal (Refereed)
    Abstract [en]

    The assessment of perceived quality based on psychophysiological methods recently gained attraction as it potentiallyovercomes certain flaws of psychophysical approaches. Although studies report promising results, it is not possible toarrive at decisive and comparable conclusions that recommend the use of one or another method for a specific applicationor research question. The video quality expert group started a project on psychophysiological quality assessment to studythese novel approaches and to develop a test plan that enables more systematic research. This test plan comprises of a specificallydesigned set of quality annotated video sequences, suggestions for psychophysiological methods to be studied inquality assessment, and recommendations for the documentation and publications of test results. The test plan is presentedin this article.

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  • 13.
    Brandt, Rasmus
    et al.
    KTH Royal Institute of Technology, Sweden.
    Mochaourab, Rami
    KTH Royal Institute of Technology, Sweden.
    Bengtsson, Mats
    KTH Royal Institute of Technology, Sweden.
    Interference Alignment-Aided Base Station Clustering using Coalition Formation2015In: Proceedings of the 49th Asilomar Conference on Signals, Systems and Computers, 2015Conference paper (Refereed)
    Abstract [en]

    Base station clustering is necessary in large interference networks, where the channel state information (CSI) acquisition overhead otherwise would be overwhelming. In this paper, we propose a novel long-term throughput model for the clustered users which addresses the balance between interference mitigation capability and CSI acquisition overhead. The model only depends on statistical CSI, thus enabling long-term clustering. Based on notions from coalitional game theory, we propose a low-complexity distributed clustering method. The algorithm converges in a couple of iterations, and only requires limited communication between base stations. Numerical simulations show the viability of the proposed approach.

  • 14.
    Brunnström, Kjell
    et al.
    RISE - Research Institutes of Sweden (2017-2019), ICT, Acreo. Mid Sweden University, Sweden.
    Barkowsky, Marcus
    University of Applied Sciences, Germany.
    Statistical quality of experience analysis: on planning the sample size and statistical significance testing2018In: Journal of Electronic Imaging (JEI), ISSN 1017-9909, E-ISSN 1560-229X, Vol. 27, no 5, article id 053013Article in journal (Refereed)
    Abstract [en]

    This paper analyzes how an experimenter can balance errors in subjective video quality tests betweenthe statistical power of finding an effect if it is there and not claiming that an effect is there if the effect is not there,i.e., balancing Type I and Type II errors. The risk of committing Type I errors increases with the number ofcomparisons that are performed in statistical tests. We will show that when controlling for this and at thesame time keeping the power of the experiment at a reasonably high level, it is unlikely that the number oftest subjects that are normally used and recommended by the International Telecommunication Union (ITU),i.e., 15 is sufficient but the number used by the Video Quality Experts Group (VQEG), i.e., 24 is more likelyto be sufficient. Examples will also be given for the influence of Type I error on the statistical significance ofcomparing objective metrics by correlation. We also present a comparison between parametric and nonparametricstatistics. The comparison targets the question whether we would reach different conclusions on the statisticaldifference between the video quality ratings of different video clips in a subjective test, based on thecomparison between the student T-test and the Mann–Whitney U-test. We found that there was hardly a differencewhen few comparisons are compensated for, i.e., then almost the same conclusions are reached. Whenthe number of comparisons is increased, then larger and larger differences between the two methods arerevealed. In these cases, the parametric T-test gives clearly more significant cases, than the nonparametrictest, which makes it more important to investigate whether the assumptions are met for performing a certaintest.

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  • 15.
    Brunnström, Kjell
    et al.
    RISE - Research Institutes of Sweden (2017-2019), ICT, Acreo. Mid Sweden University, Sweden.
    Dima, Elijs
    Mid Sweden University, Sweden.
    Andersson, Mattias
    Mid Sweden University, Sweden.
    Sjöström, Mårten
    Mid Sweden University, Sweden.
    Qureshi, Tahir
    HIAB, Sweden.
    Johanson, Mathias
    Alkit Communications AB, Sweden.
    Quality of Experience of hand controller latency in a Virtual Reality simulator2019In: Human Vision and Electronic Imaging 2019 / [ed] Damon Chandler, Mark McCourt and Jeffrey Mulligan, 2019, article id 3068450Conference paper (Refereed)
    Abstract [en]

    In this study, we investigate a VR simulator of a forestry crane used for loading logs onto a truck, mainly looking at Quality of Experience (QoE) aspects that may be relevant for task completion, but also whether there are any discomfort related symptoms experienced during task execution. A QoE test has been designed to capture both the general subjective experience of using the simulator and to study task performance. Moreover, a specific focus has been to study the effects of latency on the subjective experience, with regards to delays in the crane control interface. A formal subjective study has been performed where we have added controlled delays to the hand controller (joystick) signals. The added delays ranged from 0 ms to 800 ms. We found no significant effects of delays on the task performance on any scales up to 200 ms. A significant negative effect was found for 800 ms added delay. The Symptoms reported in the Simulator Sickness Questionnaire (SSQ) was significantly higher for all the symptom groups, but a majority of the participants reported only slight symptoms. Two out of thirty test persons stopped the test before finishing due to their symptoms.

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  • 16.
    Brunnström, Kjell
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems.
    Djupsjöbacka, Anders
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems.
    Andrén, Börje
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems.
    Objective video quality assessment methods for Video assistant refereeing (VAR) System: Phase 4 report on synchronizationand latency measurements2021Report (Other academic)
    Abstract [en]

    This report describes the work and conclusions drawn after phase 4 for the synchronization and latencymeasurements in the project “Assessment methods for Video Assistant Refereeing (VAR) System”.In phase 4, we have focused on up-dating the software so that it automatically detects: p (progressive),i (interlaced), and PsF (progressive segmented frame) formats and analyse the different video types. Wehave also the performed a field-test with an OB-van at an arena.

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  • 17.
    Carlsson, A.
    et al.
    RISE, Swedish ICT, Acreo.
    Jacobsen, G.
    RISE, Swedish ICT, Acreo.
    Anders, Berntson
    RISE, Swedish ICT, Acreo.
    Receiver Model Including Square-Law Detection and ISI from Arbitrary Electrical Filtering2003In: Conference on Optical Fiber Communication, Technical Digest Series, 2003, p. 68-69Conference paper (Refereed)
    Abstract [en]

    A dynamic receiver model, which uses the electrical filter time response to include the effects of inter-symbol-interference (ISI) was described. The model consisted an arrayed waveguide grating (AWG), a photodiode (PD), an electrical low pass filter (LPF) and a decision circuit. The model used matrix formalism, which made it directly applicable to numerical simulations. An example, measurements and numerical results on 10Gbit/s simulations, that showed the influence of ISI from a 4th order Bessel filter on the Bit Error Ratio (BER) was also presented.

  • 18.
    Carlsson, A.
    et al.
    Ericsson Telecom, Sweden.
    Jacobsen, G.
    Ericsson Telecom, Sweden.
    Anders, Berntson
    Ericsson Telecom, Sweden.
    Rigorous modeling of noise and ISI in optical WDM receivers with arbitrary electrical filtering2002In: Pacific Rim Conference on Lasers and Electro-Optics, CLEO - Technical Digest, 2002, p. 532-533Conference paper (Refereed)
    Abstract [en]

    Rigorous modeling of noise and intersymbol signal interference in optical wavelength division multiplexing receivers with arbitrary electrical filtering was presented. Simulations of a WDM back-to-back system was performed with 32 signal channels. Bit-error-rate was evaluated as a function of received power at the input to the pre-amplifier. Results indicated that for a filter with a narrow bandwidth, the impulse response was spread out, and the detected bit was affected by the impulse response from previous bits.

  • 19. Chen, Lei
    et al.
    Englund, Cristofer
    RISE, Swedish ICT, Viktoria. Halmstad University, Sweden; Chalmers University of Technology, Sweden.
    Cooperative Intersection Management: A Survey2016In: IEEE transactions on intelligent transportation systems (Print), ISSN 1524-9050, E-ISSN 1558-0016, Vol. 17, no 2, p. 570-586, article id 7244203Article in journal (Refereed)
    Abstract [en]

    Intersection management is one of the most challenging problems within the transport system. Traffic light-based methods have been efficient but are not able to deal with the growing mobility and social challenges. On the other hand, the advancements of automation and communications have enabled cooperative intersection management, where road users, infrastructure, and traffic control centers are able to communicate and coordinate the traffic safely and efficiently. Major techniques and solutions for cooperative intersections are surveyed in this paper for both signalized and nonsignalized intersections, whereas focuses are put on the latter. Cooperative methods, including time slots and space reservation, trajectory planning, and virtual traffic lights, are discussed in detail. Vehicle collision warning and avoidance methods are discussed to deal with uncertainties. Concerning vulnerable road users, pedestrian collision avoidance methods are discussed. In addition, an introduction to major projects related to cooperative intersection management is presented. A further discussion of the presented works is given with highlights of future research topics. This paper serves as a comprehensive survey of the field, aiming at stimulating new methods and accelerating the advancement of automated and cooperative intersections.

  • 20.
    Chen, Lei
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Mobility and Systems.
    Habibovic, Azra
    RISE Research Institutes of Sweden, Digital Systems, Mobility and Systems.
    Gråsjö, Mikael
    Carmenta AB, Sweden.
    Adebahr, Martin
    CEVT China Euro Vehicle Technology AB, Sweden.
    King, Philip
    Volvo Car Corporation, Sweden.
    Cloud-based traffic control: a system of systems for accelerating c-its deployment and autonomous vehicle integration2020In: Proceedings of Virtual ITS European Congress, 2020, article id Paper number ITS-TP18522Conference paper (Other academic)
    Abstract [en]

    The traffic system is transforming into a highly complex system of systems with increasing connectivity and automation. Engineering such a system of systems requires close interaction between related stakeholders including authorities, car manufacturers, and the service and technology providers, both from the organizational and technical perspective. This paper describes a cloud-based traffic control system that provides a platform to support cross-sector interoperable information sharing, and data intelligence for future connected and autonomous vehicle integration. The system is engineered from a system of systems perspective with multi-stakeholder engagement and is designed to be cloud-native for stakeholder and service scalability. The paper discusses the motivation of the system, followed by a detailed description on the system architecture and the constituent systems. Supported services are presented with their working process, information flow, as well as their public demonstrations.

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  • 21.
    Condo Neira, Edith
    Chalmers University of Technology, Sweden.
    Antenna Evaluation for VehicularApplications in Multipath Environment2017Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Antennas are essential components in any wireless communication system. To evaluate them is challenging, especially when new technologies are emerging.

    Future intelligent transport systems, where vehicular communications play an important role will cover important aspects such as traffic safety and traffic efficiency. These applications will be covered by technologies such as IEEE 802.11p and LTE. For these emerging technologies, traditional methods for measuring the vehicular antennas such as anechoic chamber measurements or expensive and time-consuming field measurements may not be enough or suitable. Thus a new method for evaluating the antennas performance is desirable. A method that includes the multipath environment to give an idea of the antenna performance in the whole system and at the same time be able to be applied at early stages of product development. This thesis aims to provide such method.

    The thesis is divided in two parts. The first part contains an overview and background of important concepts needed for development of methods for evaluation of vehicular antennas. In the second part, the papers that constitute the core of this work are appended.

    In Paper A, we evaluate the vehicle’s antenna performance using only simulations. We start by defining the multipath environment for vehicle-tovehicle and vehicle-to-infrastructure (V2X) communication. Then, the V2X environment is simulated using a multipath simulation tool to evaluate the vehicle’s antennas radiation patterns placed at different positions on the vehicle. This will result in the received power cumulative distribution functions (CDFs) for the voltage samples at the receiving antennas port.

    In Paper B, we present the design and evaluation of an antenna module for IEEE 802.11p and LTE technologies. The module is designed taking into consideration the available space and suitable placement on the vehicle. The proposed module is in accordance with the requirements for LTE and IEEE 802.11p technologies. This is validated with the analysis of the antenna efficiencies, S-parameters, radiation patterns, and diversity performance for the simulated and measured antenna module.

    Finally, Paper C presents a method for the evaluation of V2V antennas in a simulated measurement-based multipath environment. Here, a measurement campaign is performed to obtain the parameters (i.e., the angular received power spectrum) that define a realistic V2V multipath environment. These parameters are then introduced in a multipath simulation tool where the antennas radiation patterns are evaluated. Results are expressed in terms of received power CDFs. This method is validated by comparing the simulated and measured received power for two roof-top vehicle antennas.

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  • 22.
    Condo Neira, Edith
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Safety and Transport, Electronics.
    Jan, Carlsson
    RISE, SP – Sveriges Tekniska Forskningsinstitut.
    Karlsson, Kristian
    RISE - Research Institutes of Sweden (2017-2019), Safety and Transport, Electronics.
    Erik G., Ström
    Chalmers University of Technology, Sweden.
    Combined LTE and IEEE 802.11p Antenna for Vehicular Applications2015In: 2015 9th European Conference on Antennas and Propagation (EuCAP), 2015, article id 7228685Conference paper (Refereed)
    Abstract [en]

    Vehicles may contain multiple antennas for different applications. Among all of them, Vehicle-to-Vehicle and Vehicle-to-Infrastructure (V2X) is one of the most recent applications. This new technology focuses on traffic safety and traffic efficiency. In this paper we present a new compact antenna module suitable for vehicular applications. This module could be easily integrated into the rear-spoiler on a vehicle. The module consists of two identical monopoles for V2X applications based on the IEEE 802.11p standard and two identical printed inverted F-antennas for Long-Term Evolution (LTE) communications. The evaluation of the proposed module is done by analyzing the simulated and measured antenna S-parameters, antenna efficiencies, radiation patterns, as well as by calculating the diversity performance. The results show that the antennas are well matched and well isolated for both LTE and V2X and exhibits a radiation pattern close to the desired omnidirectional in the horizontal plane for V2X. The two LTE antennas have radiation patterns that complement each other ensuring an omnidirectional coverage by combination. Furthermore the module presents good radiation efficiency for both LTE and V2X.

  • 23.
    Dargie, W.
    et al.
    Technical University of Dresden, Germany.
    Schill, A.
    Technical University of Dresden, Germany.
    Mochaourab, Rami
    Technical University of Dresden, Germany.
    Guan, L.
    Loughborough University, UK.
    A Topology Control Protocol for 2D Poisson Distributed Wireless Sensor Networks2009Conference paper (Refereed)
    Abstract [en]

    Topology control in a wireless sensor network is useful for ensuring that the network remains connected in the presence of nodes that exhaust their energy or become altogether dysfunctional (for whatever reasons). It also ensures that all the link that can be established are energy-efficient links and the nodes utilize their energy fairly. In this paper, we propose a fair and energy efficient topology control protocol for a two-dimensional random sensor deployment in which the nodes can estimate the distances to their neighbors and vary their transmission power accordingly. The protocol applies a neighbor eligibility metric in order to ensure a fair distribution of energy in the network. We introduce the notion of weighted relaying regions defined over the plane of a searching node to drop out inefficient links. Unlike most topology control protocols that rely on nearest neighbor approaches, we use a distance measure that is radio characteristic and channel condition dependent. We verify the performance of the protocol through simulation results on network graph properties and energy consumption.

  • 24.
    Dima, Elijs
    et al.
    Mid Sweden University, Sweden.
    Brunnström, Kjell
    RISE - Research Institutes of Sweden (2017-2019), ICT, Acreo. Mid Sweden University, Sweden.
    Sjöström, Mårten
    Mid Sweden University, Sweden.
    Andersson, Mattias
    Mid Sweden University, Sweden.
    Edlund, Joakim
    Mid Sweden University, Sweden.
    Johanson, Mathias
    Alkit Communications AB, Sweden.
    Qureshi, Tahir
    HIAB AB, Sweden.
    View Position Impact on QoE in an Immersive Telepresence System for Remote Operation2019In: 2019 Eleventh International Conference on Quality of Multimedia Experience (QoMEX), Berlin, Germany: IEEE , 2019Conference paper (Refereed)
    Abstract [en]

    In this paper, we investigate how different viewingpositions affect a user’s Quality of Experience (QoE) and performancein an immersive telepresence system. A QoE experimenthas been conducted with 27 participants to assess the generalsubjective experience and the performance of remotely operatinga toy excavator. Two view positions have been tested, an overheadand a ground-level view, respectively, which encourage relianceon stereoscopic depth cues to different extents for accurate operation.Results demonstrate a significant difference between groundand overhead views: the ground view increased the perceiveddifficulty of the task, whereas the overhead view increased theperceived accomplishment as well as the objective performanceof the task. The perceived helpfulness of the overhead view wasalso significant according to the participants.

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  • 25.
    Dima, Elijs
    et al.
    Mid Sweden University, Sweden.
    Brunnström, Kjell
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems. Mid Sweden University, Sweden.
    Sjöström, Mårten
    Mid Sweden University, Sweden.
    Andersson, Mattias
    Mid Sweden University, Sweden.
    Edlund, Joakim
    Mid Sweden University, Sweden.
    Johansson, Mathias
    Alkit Communications AB, Sweden.
    Qureshi, Tahir
    HIAB AB, Sweden.
    Joint effects of depth‑aiding augmentations and viewing positionson the quality of experience in augmented telepresence2020In: Quality and User Experience, ISSN 2366-0139, Vol. 5, article id 2Article in journal (Refereed)
    Abstract [en]

    Virtual and augmented reality is increasingly prevalent in industrial applications, such as remote control of industrial machinery,due to recent advances in head-mounted display technologies and low-latency communications via 5G. However, theinfluence of augmentations and camera placement-based viewing positions on operator performance in telepresence systemsremains unknown. In this paper, we investigate the joint effects of depth-aiding augmentations and viewing positionson the quality of experience for operators in augmented telepresence systems. A study was conducted with 27 non-expertparticipants using a real-time augmented telepresence system to perform a remote-controlled navigation and positioningtask, with varied depth-aiding augmentations and viewing positions. The resulting quality of experience was analyzed viaLikert opinion scales, task performance measurements, and simulator sickness evaluation. Results suggest that reducing thereliance on stereoscopic depth perception via camera placement has a significant benefit to operator performance and qualityof experience. Conversely, the depth-aiding augmentations can partly mitigate the negative effects of inferior viewingpositions. However the viewing-position based monoscopic and stereoscopic depth cues tend to dominate over cues basedon augmentations. There is also a discrepancy between the participants’ subjective opinions on augmentation helpfulness,and its observed effects on positioning task performance.

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    fulltext
  • 26.
    Djupsjöbacka, Anders
    Ericsson, Sweden.
    A linearization concept for integrated-optic modulators1992In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 4, no 8, p. 869-872Article in journal (Refereed)
    Abstract [en]

    A novel linearization concept to reduce the distortion products from integrated-optic modulators is proposed and analyzed. The proposed linearization concept could be used on any type of modulator with an odd transfer function. A dual parallel Mach-Zehnder modulator was linearized, and the results are compared to those obtained using a conventional linearization concept. The proposed concept gives a 40% higher modulation index compared to a concept based on reduction of the cubic nonlinearity of the modulator

  • 27.
    Djupsjöbacka, Anders
    Ericsson, Sweden.
    Prechirped duobinary modulation1998In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 10, no 8, p. 1159-1161Article in journal (Refereed)
    Abstract [en]

    The proposed modulation scheme enables us to combine the advantages of the duobinary modulation, i.e., reduced transmission bandwidth compared to traditional intensity modulation, together with the advantages of prechirped modulation. Below, a theoretical investigation is presented where four different methods of modulating a double electrode Mach-Zehnder modulator is compared. It will be shown that the proposed prechirped duobinary modulation scheme will have the best performance in terms of power penalty.

  • 28.
    Djupsjöbacka, Anders
    Ericsson, Sweden.
    Time division multiplexing using optical switches1988In: IEEE Journal on Selected Areas in Communications, ISSN 0733-8716, E-ISSN 1558-0008, Vol. 6, no 7, p. 1227-1231Article in journal (Refereed)
    Abstract [en]

    Design considerations are considered for optical time-division multiplexing in terms of bandwidth requirements for the modulators and switches for a particular multiplexing scheme and the corresponding drive signals are derived using a time-domain approach. It is shown that these requirements are stricter than expected from simple considerations. Different types of multiplexing schemes are analyzed and are shown to behave differently due to varying chirping properties; this chirping is also calculated. A comparison to nonmultiplexed systems is made

  • 29.
    Djupsjöbacka, Anders
    KTH Royal Institute of Technology, Sweden.
    Traveling Wave Modulators in Lithum Niobate1995Doctoral thesis, monograph (Other academic)
  • 30.
    Fan, Yuchuan
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems. KTH Royal Institute of Technology, Sweden.
    Pang, Xiaodan
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems. KTH Royal Institute of Technology, Sweden.
    Udalcovs, Aleksejs
    RISE Research Institutes of Sweden.
    Natalino, Carlos
    Chalmers University of Technology, Sweden.
    Schatz, Richard
    KTH Royal Institute of Technology, Sweden.
    Furdek, Marija
    Chalmers University of Technology, Sweden.
    Popov, Sergei
    KTH Royal Institute of Technology, Sweden.
    Ozolins, Oskars
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems. KTH Royal Institute of Technology, Sweden.
    Laser Linewidth Tolerant EVM Estimation Approach for Intelligent Signal Quality Monitoring Relying on Feedforward Neural Networks2021In: 2021 European Conference on Optical Communication (ECOC), 2021Conference paper (Refereed)
    Abstract [en]

    Robustness against the large linewidth semiconductor laser-induced impairments in coherent systems is experimentally demonstrated for a feedforward neural network-enabled EVM estimation scheme. A mean error of 0.4% is achieved for 28 Gbaud square and circular QAM signals and linewidths up to 12.3 MHz.

  • 31.
    Fan, Yuchuan
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems. KTH Royal Institute of Technology, Sweden.
    Pang, Xiaodan
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems. KTH Royal Institute of Technology, Sweden.
    Udalcovs, Aleksejs
    RISE Research Institutes of Sweden, Digital Systems.
    Natalino, Carlos
    Chalmers University of Technology, Sweden.
    Zhang, Lu
    Zhejiang University, Hangzhou, China; Zhejiang Lab, China.
    Spolitis, Sandis
    Riga Technical University, Latvia.
    Bobrovs, Vjaceslavs
    Riga Technical University, Latvia.
    Schatz, Richard
    KTH Royal Institute of Technology, Sweden.
    Yu, Xianbin
    Zhejiang University, Hangzhou, China; Zhejiang Lab, China.
    Furdek, Marija
    Chalmers University of Technology, Sweden.
    Popov, Sergei
    KTH Royal Institute of Technology, Sweden.
    Ozolins, Oskars
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems. KTH Royal Institute of Technology, Sweden; Zhejiang Lab, China.
    Linear Regression vs. Deep Learning for Signal Quality Monitoring in Coherent Optical Systems2022In: IEEE Photonics Journal, E-ISSN 1943-0655, Vol. 14, no 4, article id 8643108Article in journal (Refereed)
    Abstract [en]

    Error vector magnitude (EVM) is a metric for assessing the quality of m-ary quadrature amplitude modulation (mQAM) signals. Recently proposed deep learning techniques, e.g., feedforward neural networks (FFNNs) -based EVM estimation scheme leverage fast signal quality monitoring in coherent optical communication systems. Such a scheme estimates EVM from amplitude histograms (AHs) of short signal sequences captured before carrier phase recovery (CPR). In this work, we explore further complexity reduction by proposing a simple linear regression (LR) -based EVM monitoring method. We systematically compare the performance of the proposed method with the FFNN-based scheme and demonstrate its capability to infer EVM from an AH when the modulation format information is known in advance. We perform both simulation and experiment to show that the LR-based EVM estimation method achieves a comparable accuracy as the FFNN-based scheme. The technique can be embedded with modulation format identification modules to provide comprehensive signal information. Therefore, this work paves the way to design a fast-learning scheme with parsimony as a future intelligent OPM enabler. 

  • 32.
    Fan, Yuchuan
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems.
    Udalcovs, Aleksejs
    RISE Research Institutes of Sweden.
    Natalino, Carlos
    Chalmers University of Technology, Sweden.
    Pang, Xiaodan
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems. KTH Royal Institute of Technology, Sweden.
    Schatz, Richard
    KTH Royal Institute of Technology, Sweden.
    Furdek, Marija
    Chalmers University of Technology, Sweden.
    Popov, Sergei
    KTH Royal Institute of Technology, Sweden.
    Ozolins, Oskars
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems. KTH Royal Institute of Technology, Sweden.
    Experimental validation of CNNs versus FFNNs for time- and energy-efficient EVM estimation in coherent optical systems2021In: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 13, no 10, p. E63-E71Article in journal (Refereed)
    Abstract [en]

    Error vector magnitude (EVM) has proven to be one of the optical performance monitoring metrics providing the quantitative estimation of error statistics. However, the EVM estimation efficiency has not been fully exploited in terms of complexity and energy consumption. Therefore, in this paper, we explore two deep-learning-based EVM estimation schemes. The first scheme exploits convolutional neural networks (CNNs) to extract EVM information from images of the constellation diagram in the in-phase/quadrature (IQ) complex plane or amplitude histograms (AHs). The second scheme relies on feedforward neural networks (FFNNs) extracting features from a vectorized representation of AHs. In both cases, we use short sequences of 32 Gbaud m-ary quadrature amplitude modulation (mQAM) signals captured before or after a carrier phase recovery. The impacts of the sequence length, neural network structure, and data set representation on the EVM estimation accuracy as well as the model training time are thoroughly studied. Furthermore, we validate the performance of the proposed schemes using the experimental implementation of 28 Gbaud 64QAM signals. We achieve a mean absolute estimation error below 0.15%, with short signals consisting of only 100 symbols per IQ cluster. Considering the estimation accuracy, the implementation complexity, and the potential energy savings, the proposed CNN- and FFNN-based schemes can be used to perform time-sensitive and accurate EVM estimation for mQAM signal quality monitoring purposes.

  • 33.
    Fan, Yuchuan
    et al.
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems. KTH Royal Institute of Technology, Sweden.
    Udalcovs, Aleksejs
    RISE Research Institutes of Sweden.
    Pang, Xiaodan
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems. KTH Royal Institute of Technology, Sweden.
    Natalino, C.
    Chalmers University of Technology, Sweden.
    Schatz, Richard
    KTH Royal Institute of Technology, Sweden.
    Furdek, M.
    Chalmers University of Technology, Sweden.
    Popov, Sergei
    KTH Royal Institute of Technology, Sweden.
    Ozolins, Oskars
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems. KTH Royal Institute of Technology, Sweden.
    Deep learning assisted pre-carrier phase recovery EVM estimation for coherent transmission systems2021In: Optics InfoBase Conference Papers 2021 Article number STh1F.2, The Optical Society , 2021Conference paper (Refereed)
    Abstract [en]

    We exploit deep supervised learning and amplitude histograms of coherent optical signals captured before carrier phase recovery (CPR) to perform time-sensitive and accurate error vector magnitude (EVM) estimation for 32 Gbaud mQAM signal monitoring purposes. © OSA 2021, © 2021 The Author(s)

  • 34.
    Forzati, Marco
    et al.
    RISE, Swedish ICT, Acreo.
    Anders, Berntson
    RISE, Swedish ICT, Acreo.
    Mårtensson, J.
    RISE, Swedish ICT, Acreo.
    Ifwm suppression by asynchronous phase modulation2006In: 2006 European Conference on Optical Communications Proceedings, ECOC 2006, 2006Conference paper (Refereed)
    Abstract [en]

    We propose a cost-effective way to increase the non-linear tolerance of all channels in a 40-Gb/s WDM transmission system, which is shown to greatly improve the performance of RZ and especially NRZ transmission.

  • 35.
    Forzati, Marco
    et al.
    RISE, Swedish ICT, Acreo.
    Anders, Berntson
    RISE, Swedish ICT, Acreo.
    Mårtensson, J.
    RISE, Swedish ICT, Acreo.
    Davies, R. J.
    TRLabs,, Norway.
    Performance analysis of single-MZM APRZ transmitter2005In: IET Conference Publications, Institution of Engineering and Technology , 2005, no CP502, p. 663-664Conference paper (Refereed)
    Abstract [en]

    We present the first numerical study of 67%-duty-cycle single-MZM APRZ, comparing it with 33% RZ, 33% APRZ and standard CSRZ. This transmitter is shown to combine CSRZ implementation simplicity with the improved nonlinear tolerance of π/2-APRZ.

  • 36.
    Forzati, Marco
    et al.
    RISE, Swedish ICT, Acreo.
    Anders, Berntson
    RISE, Swedish ICT, Acreo.
    Mårtensson, J.
    RISE, Swedish ICT, Acreo.
    Djupsjöbacka, Anders
    RISE, Swedish ICT, Acreo.
    IFWM suppression in NRZ transmission experiment at 40 Gb/s using asynchronous phase modulation2007In: Optics InfoBase Conference Papers, Optical Society of America , 2007Conference paper (Refereed)
    Abstract [en]

    The Asynchronous Phase Modulation (APM) scheme is experimentally studied for the first time. APM is shown to increase the power tolerance of NRZ-OOK over a 3x75-km link. © 2006 Optical Society of America.

  • 37. Forzati, Marco
    et al.
    Anders, Berntson
    RISE, Swedish ICT, Acreo.
    Mårtensson, J.
    RISE, Swedish ICT, Acreo.
    Pincemin, E.
    RISE, Swedish ICT, Acreo.
    Gavignet, P.
    RISE, Swedish ICT, Acreo.
    NRZ-OOK transmission of 16×40 Gb/s over 2800 km SSMF using asynchronous phase modulation2008In: 2008 Conference on Quantum Electronics and Laser Science Conference on Lasers and Electro-Optics, CLEO/QELS, 2008Conference paper (Refereed)
    Abstract [en]

    We use the cost-effective APM technique to increase the non-linear tolerance of NRZ-OOK, and we demonstrate, in a recirculating loop experiment, the transmission over 2800 km SSMF of 16 NRZ-OOK 40 Gb/s channels with 100 GHz spacing.

  • 38.
    Forzati, Marco
    et al.
    RISE, Swedish ICT, Acreo.
    Anders, Berntson
    RISE, Swedish ICT, Acreo.
    Mårtensson, J.
    RISE, Swedish ICT, Acreo.
    Pincemin, E.
    RISE, Swedish ICT, Acreo.
    Gavignet, P.
    RISE, Swedish ICT, Acreo.
    NRZ-OOK transmission of 16£40 Gb/s Over 2800 km SSMF using asynchronous phase modulation2008In: Optics InfoBase Conference Papers, Optical Society of America , 2008Conference paper (Refereed)
    Abstract [en]

    We use the cost-e®ective APM technique to increase the non-linear tolerance of NRZ-OOK, and we demonstrate, in a recirculating loop experiment, the transmission over 2800 km SSMF of 16 NRZ-OOK 40 Gb/s channels with 100 GHz spacing. © 2007 Optical Society of America.

  • 39.
    Forzati, Marco
    et al.
    RISE, Swedish ICT, Acreo.
    Anders, Berntson
    RISE, Swedish ICT, Acreo.
    Mårtensson, Jonas
    RISE, Swedish ICT, Acreo.
    Djupsjöbacka, Anders
    RISE, Swedish ICT, Acreo.
    Li, J.
    RISE, Swedish ICT, Acreo.
    Melin, S.
    TeliaSonera AB, Sweden.
    Carlden, H.
    TeliaSonera AB, Sweden.
    40-gb/s field transmission through 540 km ssmf using the aprz modulation format2005In: Optics InfoBase Conference Papers, Optical Society of America , 2005Conference paper (Refereed)
    Abstract [en]

    We report the first field transmission experiment using the APRZ modulation format for 40-Gb/s transmission through 540 km SSMF, which confirms the improved nonlinear tolerance of APRZ. The optimum phase-modulation amplitude in this experiment is p/2. 

  • 40.
    Ghauch, Hadi
    et al.
    KTH Royal Institute of Technology, Sweden.
    Mochaourab, Rami
    KTH Royal Institute of Technology, Sweden.
    Bengtsson, Mats
    KTH Royal Institute of Technology, Sweden.
    Skoglund, Mikael
    KTH Royal Institute of Technology, Sweden.
    Distributed precoding and user selection in MIMO interfering networks2015In: 2015 IEEE 6th International Workshop on Computational Advances in Multi-Sensor Adaptive Processing, CAMSAP 2015, 2015, p. 461-464Conference paper (Refereed)
    Abstract [en]

    In this work we shed light on the problem of precoding and user selection in MIMO networks. We formulate the problem using the framework of stable matching, whereby a set of users wish to be matched to a set of serving base stations, such as to maximize the sum-rate performance of the system. Though the problem is NP-hard, we propose a suboptimal heuristic that tackles the problem in a distributed fashion: we apply a many-to-one stable matching algorithm to generate a sequence of matchings, and the Weighted MMSE algorithm to perform the precoding. We benchmark our algorithm againt the recently proposed Weighted MMSE with User Assignment algorithm.

  • 41.
    Guimarães, Carlos
    et al.
    University Carlos III de Madrid, Spain.
    Groshev, Milan
    University Carlos III de Madrid, Spain.
    Cominardi, Luca
    ADLINK Technology, Taiwan.
    Zabala, Aitor
    Telcaria Ideas SL, Spain.
    Contreras, Luis
    Telefónica I+D, Spain.
    Talat, Samer
    Industrial Technology Research Institute, Taiwan.
    Zhang, Chao
    Lund University, Sweden.
    Hazra, Saptarshi
    RISE Research Institutes of Sweden, Digital Systems, Data Science.
    Mourad, Alain
    InterDigital Europe, UK.
    de la Oliva, Antonio
    University Carlos III de Madrid, Spain.
    DEEP: A Vertical-Oriented Intelligent and Automated Platform for the Edge and Fog2021In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 59, no 6, p. 66-72Article in journal (Refereed)
    Abstract [en]

    The fifth generation (5G) of mobile communications introduces improvements on many fronts when compared to its previous generations. Besides the performance enhancements and new advances in radio technologies, it also integrates other technological domains, such as cloud-to-things continuum and artificial intelligence. In this work, the 5G-DIVE Elastic Edge Platform (DEEP) is proposed as the linking piece for the integration of these technological domains, making available an intelligent edge and fog 5G end-to-end solution. This solution brings numerous benefits to vertical industries by enabling streamlined, abstracted, and automated management of their vertical services, thus contributing to the introduction of novel services, cost savings, and improved time to market. Preliminary validation of the proposed platform is performed through a proof of concept, along with a qualitative analysis of its benefits for Industry 4.0 and autonomous drone scouting vertical industries.

  • 42.
    Gutierrez, Jesus
    et al.
    University Politcnica de Madrid, Spain.
    Perez, Pablo
    Nokia Bell Labs, Spain.
    Orduna, Marta
    University Politcnica de Madrid, Spain.
    Singla, Ashutosh
    Technical University of Ilmenau, Germany.
    Cortes, Carlos
    University Politcnica de Madrid, Spain.
    Mazumdar, Pramit
    University degli Studi Roma Tre, Italy.
    Viola, Irene
    CWI, Netherlands.
    Brunnström, Kjell
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems.
    Battisti, Frederica
    Roma Tre University, Italy.
    Cieplinska, Natalia
    AGH University of Science and Technology, Poland.
    Juszka, Dawid
    AGH University of Science and Technology, Poland.
    Janowski, Lucjan
    AGH University of Science and Technology, Poland.
    Leszczuk, Mikoaj
    AGH University of Science and Technology, Poland.
    Adeyemi-ejeye, Femi
    University of Surrey, UK.
    Hu, Yaosi
    Wuhan University, China.
    Chen, Zhengzhong
    Wuhan University, China.
    Van Wallendael, Glenn
    Universiteit Gent, Belgium.
    Lambert, Peter
    Universiteit Gent, Belgium.
    Diaz, Cesar
    University Politecnica de Madrid, Spain.
    Hedlund, John
    RISE Research Institutes of Sweden.
    Hamsis, Omar
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems.
    Fremerey, Stephan
    Technical University of Ilmenau, Germany.
    Hofmeyer, Frank
    Technical University of Ilmenau, Germany.
    Raake, Alexander
    Technical University of Ilmenau, Germany.
    Cesar, Pablo
    CWI, Netherlands.
    Subjective evaluation of visual quality and simulator sickness of short 360 videos: ITU-T Rec. P.9192022In: IEEE transactions on multimedia, ISSN 1520-9210, E-ISSN 1941-0077, Vol. 24, p. 3087-3100Article in journal (Refereed)
    Abstract [en]

    Recently an impressive development in immersive technologies, such as Augmented Reality (AR), Virtual Reality (VR) and 360 video, has been witnessed. However, methods for quality assessment have not been keeping up. This paper studies quality assessment of 360 video from the cross-lab tests (involving ten laboratories and more than 300 participants) carried out by the Immersive Media Group (IMG) of the Video Quality Experts Group (VQEG). These tests were addressed to assess and validate subjective evaluation methodologies for 360 video. Audiovisual quality, simulator sickness symptoms, and exploration behavior were evaluated with short (from 10 seconds to 30 seconds) 360 sequences. The following factors' influences were also analyzed: assessment methodology, sequence duration, Head-Mounted Display (HMD) device, uniform and non-uniform coding degradations, and simulator sickness assessment methods. The obtained results have demonstrated the validity of Absolute Category Rating (ACR) and Degradation Category Rating (DCR) for subjective tests with 360 videos, the possibility of using 10-second videos (with or without audio) when addressing quality evaluation of coding artifacts, as well as any commercial HMD (satisfying minimum requirements). Also, more efficient methods than the long Simulator Sickness Questionnaire (SSQ) have been proposed to evaluate related symptoms with 360 videos. These results have been instrumental for the development of the ITU-T Recommendation P.919. Finally, the annotated dataset from the tests is made publicly available for the research community.

  • 43.
    Gómez, Blas
    et al.
    University of Castilla-La Mancha, Spain.
    Coronado, Estefania
    i2CAT Foundation, Spain.
    Villalón, Jose
    University of Castilla-La Mancha, Spain.
    Riggio, Roberto
    RISE Research Institutes of Sweden, Digital Systems, Data Science.
    Garrido, Antonio
    University of Castilla-La Mancha, Spain.
    WiMCA: multi-indicator client association in software-defined Wi-Fi networks2021In: Wireless networks, ISSN 1022-0038, E-ISSN 1572-8196, Vol. 27, p. 3109-Article in journal (Refereed)
    Abstract [en]

    In a world with increasing traffic demands, wireless technologies aim to meet them by means of new Radio Access Technologies that provide faster connectivity. Such is the case of 4G and 5G. However, in indoor scenarios, where the capabilities of these technologies are significantly affected by the distance to the base station and the materials used in the construction of buildings, Wi-Fi is still the technology of reference thanks to its low cost and easy deployment. In this context, it is usual to find multi-AP Wi-Fi networks whose deployment has been carefully planned. However, the user-AP association decision procedure is not defined by the IEEE 802.11 standard. As a result, vendors choose selfish approaches based on signal strength. This leads to uneven user distributions and nonoptimal resource utilization. To deal with this, densification has been used over the years, but this is expensive as it needs more infrastructure. Moreover, this results in more APs in the same collision domain. To avoid the need for densification, in this paper we introduce WiMCA, a joint SDN-based user association and channel assignment solution for Wi-Fi networks that considers signal strength, channel occupancy and AP load to make better association decisions. Experimental results have demonstrated that, in terms of aggregated goodput, WiMCA outperforms approaches based on signal strength by 55%, providing better user level fairness and accommodating more users and traffic before reaching the point at which densification is needed. © 2021, The Author(s)

  • 44.
    Habibovic, Azra
    et al.
    RISE Research Institutes of Sweden.
    Chen, Lei
    RISE Research Institutes of Sweden, Digital Systems, Mobility and Systems.
    Connected Automated Vehicles: Technologies, Developments, and Trends2021In: International Encyclopedia of Transportation / [ed] Roger Vickerman, Elsevier, 2021, p. 180-188Chapter in book (Other academic)
  • 45.
    Han, M.
    et al.
    Beijing Jiaotong University, Sweden; KTH Royal Institute of Technology, Sweden.
    Wang, M.
    Beijing Jiaotong University, Sweden.
    Fan, Yuchuan
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems.
    Salgals, T.
    Riga Technical University, Latvia.
    Louchet, H.
    Keysight Technologies GmbH, Germany.
    Schatz, R.
    KTH Royal Institute of Technology, Sweden.
    Gruen, M.
    Keysight Technologies GmbH, Germany.
    Pittala, F.
    Keysight Technologies GmbH, Germany.
    Krüger, B.
    Keysight Technologies GmbH, Germany.
    Dippon, T.
    Keysight Technologies GmbH, Germany.
    Zhang, L.
    Zhejiang University, China; Zhejiang Lab, China.
    Yu, X.
    Zhejiang University, China; Zhejiang Lab, China.
    Spolitis, S.
    Riga Technical University, Latvia; .
    Bobrovs, V.
    Riga Technical University, Latvia.
    Popov, Sergei
    KTH Royal Institute of Technology, Sweden.
    Pang, Xiaodan
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems. KTH Royal Institute of Technology, Sweden.
    Ozolins, Oskars
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems. KTH Royal Institute of Technology, Sweden.
    Optical amplification-free deep reservoir computing-assisted high-baudrate short-reach communication2023In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 48, no 8, p. 2122-2125Article in journal (Refereed)
    Abstract [en]

    An optical amplification-free deep reservoir computing (RC)-assisted high-baudrate intensity modulation direct detection (IM/DD) system is experimentally demonstrated using a 100G externally modulated laser operated in C-band. We transmit 112 Gbaud 4-level pulse amplitude modulation (PAM4) and 100 Gbaud 6-level PAM (PAM6) signals over a 200-m single-mode fiber (SMF) link without any optical amplification. The decision feedback equalizer (DFE), shallow RC, and deep RC are adopted in the IM/DD system to mitigate impairment and improve transmission performance. Both PAM transmissions over a 200-m SMF with bit error rate (BER) performance below 6.25% overhead hard-decision forward error correction (HD-FEC) threshold are achieved. In addition, the BER of the PAM4 signal is below the KP4-FEC limit after 200-m SMF transmission enabled by the RC schemes. Thanks to the use of a multiple-layer structure, the number of weights in deep RC has been reduced by approximately 50% compared with the shallow RC, whereas the performance is comparable. We believe that the optical amplification-free deep RC-assisted high-baudrate link has a promising application in intra-data center communications.

  • 46.
    Han, M.
    et al.
    Beijing Jiaotong University, China; KTH Royal Institute of Technology, Sweden.
    Wang, M.
    Beijing Jiaotong University, China.
    Fan, Yuchuan
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems. KTH Royal Institute of Technology, Sweden.
    Salgals, T.
    Riga Technical University, Latvia.
    Louchet, H.
    Keysight Technologies GmbH, Germany.
    Schatz, Richard
    KTH Royal Institute of Technology, Sweden.
    Gruen, M.
    Keysight Technologies GmbH, Germany.
    Pittala, F.
    Keysight Technologies GmbH, Germany.
    Krüger, B.
    Keysight Technologies GmbH, Germany.
    Dippon, T.
    Keysight Technologies GmbH, Germany.
    Zhang, L.
    Zhejiang University, China.
    Yu, X.
    Zhejiang University, China.
    Spolitis, S.
    Riga Technical University, Latvia.
    Bobrovs, V.
    Riga Technical University, Latvia.
    Popov, Sergei
    KTH Royal Institute of Technology, Sweden.
    Pang, Xiaodan
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems. KTH Royal Institute of Technology, Sweden; Riga Technical University, Latvia.
    Ozolins, Oskars
    RISE Research Institutes of Sweden, Digital Systems, Industrial Systems. KTH Royal Institute of Technology, Sweden; Riga Technical University, Latvia.
    Deep Reservoir Computing for 100 Gbaud PAM6 IM/DD Transmission Impairment Mitigation2023In: Opt. Fiber Commun. Conf. Exhib., OFC - Proc., Institute of Electrical and Electronics Engineers Inc. , 2023Conference paper (Refereed)
    Abstract [en]

    We experimentally evaluate a deep Reservoir Computing (RC)-based post-equalization for 100 Gbaud PAM6 IM/DD transmissions. It achieves ∼1 dB higher sensitivity than DFE, and ∼50% implementation complexity reduction compared with the conventional RC configuration.

  • 47.
    Helczynski, L.
    et al.
    Chalmers University of Technology, Sweden.
    Anders, Berntson
    Ericsson Telecom, Sweden.
    Comparison of EDFA and bidirectionally pumped raman amplifier in a 40-Gb/s RZ transmission system2001In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 13, no 7, p. 669-671Article in journal (Refereed)
    Abstract [en]

    We numerically compare the performance of a bidirectionally pumped Raman- and an erbium-doped fiber amplifier (EDFA) system in a 40-Gb/s dispersion-managed return-to-zero (RZ) transmission. The Raman amplifier system shows a substantially higher Q-value compared to that of the EDFA.

  • 48.
    Hess, Andrea
    et al.
    RISE - Research Institutes of Sweden (2017-2019), ICT, SICS.
    Marsh, Ian
    RISE - Research Institutes of Sweden (2017-2019), ICT, SICS.
    Gillblad, Daniel
    RISE - Research Institutes of Sweden (2017-2019), ICT, SICS.
    Exploring communication and mobility behaviour of 3G network users and its temporal consistency2015Conference paper (Refereed)
    Abstract [en]

    Over the past decade, telecommunication network operators have more and more realized the added value of data analytics for their network deployment efficiency. Early studies targeted the global network perspective by localizing peak loads, both in terms of area and time period. Due to their higher granularity and information richness, current telecommunication datasets allow increasingly deeper insights into the network activities of the users. Existing network traffic classification studies tend to divide users into groups without considering the transitions between different groups caused by individual behavioral traits, which we expect to show observable regularities. Our approach defines a profiling model that characterizes the user behavior as well as its temporal dynamics from two perspectives: w.r.t. (i) the network load the users generate, and (ii) their mobility patterns. The model is evaluated with two unsupervised clustering algorithms of different complexity (namely, XMeans and EM) by means of a 3G trace dataset from a European operator.

  • 49.
    Ho, K. M. Z.
    et al.
    Eurecom Institute, France.
    Gesbert, D.
    Eurecom Institute, France.
    Jorswieck, E.
    Dresden University of Technology, Germany.
    Mochaourab, Rami
    Dresden University of Technology, Germany.
    Beamforming on the MISO interference channel with multi-user decoding capability2010Conference paper (Refereed)
    Abstract [en]

    This paper considers the multiple-input-single-output interference channel (MISO-IC) in which transmitters and receivers share the same time and frequency resources. We consider receivers with interference decoding capability (IDC) so that the interference signal can be decoded and subtracted from the received signal. On the MISO-IC with single user decoding, transmit beamforming vectors are designed to mitigate interference at the receivers. With IDC, receivers can potentially decode interference which yields a higher data rate. Yet, decoding interference pose a rate constraint on the interferer and in turn on the sum rate of the system. This brings some interesting questions: when should the Txs mitigate interference and when should Txs amplify interference? Under what situations should Txs change from mitigating interference to amplifying interference? We answer these questions in this paper.

  • 50.
    Holfeld, B.
    et al.
    Fraunhofer, Germany.
    Mochaourab, Rami
    Fraunhofer, Germany.
    Wirth, T.
    Fraunhofer, Germany.
    Stable Matching for Adaptive Cross-Layer Scheduling in LTE Downlink2013In: 2013 IEEE 77TH VEHICULAR TECHNOLOGY CONFERENCE (VTC SPRING), 2013Conference paper (Refereed)
    Abstract [en]

    Resource allocation from base stations to mobile users in realistic MIMO-OFDMA systems such as the 3GPP Long Term Evolution (LTE) downlink is based on limited and quantized channel feedback over a fine-granular resource grid of multiple dimensions. This allows for opportunistic scheduling but impedes application of enhanced cross-layer strategies due to the discrete and combinatorial problem space. Integer optimization for this allocation problem is strongly complex and prohibits use of efficient algorithms. Provided solutions in practice are given by sub-optimal greedy heuristics. In this paper, we apply two-sided stable matchings for adaptive multi-user scheduling. Our framework gives Pareto-efficient allocations and yields a tunable tradeoff between system throughput and user fairness. We form stable pairings of system resources and users based on queue-and channel-aware lists of preferred matches. The derived concept aims to find a stable matching state under presence of non-strict preference relations if such exist or redefines the allocation problem to a solvable strict problem instance. A performance evaluation for scheduling is done by system level simulations for high traffic loads in a realistically modeled LTE deployment.

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