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  • 1.
    Bajracharya, Rojeena
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Shrestha, Rakesh
    Res Inst Sweden RISE, S-72212 Västerås, Sweden..
    Jung, Haejoon
    Kyung Hee Univ, Dept Elect Engn, Yongin 17104, South Korea..
    Shin, Hyundong
    Kyung Hee Univ, Dept Elect Engn, Yongin 17104, South Korea..
    Neutral Host Technology: The Future of Mobile Network Operators2022In: IEEE Access, E-ISSN 2169-3536, Vol. 10, p. 99221-99234Article in journal (Refereed)
    Abstract [en]

    The neutral host network (NHN) is a new self-contained network envisioned by fifth generation (5G) of cellular networks, which offers wireless connection to its subscribers from a variety of service providers, including both conventional mobile network operators and non-conventional service providers. The NHN infrastructure, which is operated and maintained by a third neutral party, is rented or leased to network operators looking to scale up their network capacities and coverage in a cost-effective way. This paper highlights NHN as an emerging communication technology for private networks and discuss its opportunities and challenges in realizing multi-tenanted space such as factory, hospitals, stadiums, and universities. The paper also investigates the current state of the art in NHN and elaborates on the underlying enabling technologies for the NHN. Lastly, an efficient radio access network (RAN) slicing scheme based on the multi-arm bandit approach has been proposed to allocate radio resources to various slices, which maximizes resource utilization while guaranteeing the availability of resources to meet the capacity needs of each multi-tenanted operator. The simulation results show that the proposed Thompson's sampling (TS)-based approach performs best in finding the optimal RAN slice for all the operators.

  • 2.
    Bilstrup, Katrin
    et al.
    Högskolan i Halmstad, Inbyggda system (CERES).
    Böhm, Annette
    Högskolan i Halmstad, Inbyggda system (CERES).
    Lidström, Kristoffer
    Högskolan i Halmstad, Inbyggda system (CERES).
    Jonsson, Magnus
    Högskolan i Halmstad, Inbyggda system (CERES).
    Larsson, Tony
    Högskolan i Halmstad, Inbyggda system (CERES).
    Uhlemann, Elisabeth
    Högskolan i Halmstad, Inbyggda system (CERES).
    Report on the Collaboration between CVIS and CERES in the Project Vehicle Alert System (VAS)2009Report (Other academic)
    Abstract [en]

    In March 2007, an agreement was made for interchange of experiences between CVIS and the Centre for Research on Embedded Systems (CERES) at Halmstad University in Sweden. The majority of the work relating to this collaboration has been conducted within the CERES project Vehicle Alert System (VAS), aiming to use vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications to provide different types of warning messages. The main focus of the VAS project is on communication and in particular the lower layers of the communication stack are investigated. VAS involves academic researchers from Halmstad University as well as researchers from Volvo Technology, SP Technical Research Institute of Sweden and the company Free2move. This report presents the results of the VAS project, its publications, and other issues of interest both to the CVIS consortium as well as a broader scope.

  • 3.
    Bilstrup, Katrin
    et al.
    Högskolan i Halmstad, Inbyggda system (CERES).
    Uhlemann, Elisabeth
    Högskolan i Halmstad, Inbyggda system (CERES).
    Ström, Erik G.
    Chalmers.
    Medium access control in vehicular networks based on the upcoming IEEE 802.11p standard2008In: 15th World Congress on Intelligent Transport Systems and ITS America Annual Meeting 2008, World Congress on ITS , 2008, p. 4155-4167Conference paper (Refereed)
    Abstract [en]

    In this paper, initial simulations are presented showing that the upcoming IEEE 802.11p standard is not suitable for traffic safety applications requiring reliable, low delay communication between vehicles. The medium access control procedure is one of the most important parts in the design of delay-constrained communication systems, and emerging vehicle safety applications put new stringent demands on timely and reliable delivery of data packets. The medium access procedure used in 802.11p is carrier sense multiple access, which is inherently unsuitable for time-critical data traffic since it is contention-based and cannot provide a finite upper bound on the time to channel access. The simulation results indicate that with IEEE 802.11p, channel access cannot be granted in a manner that is sufficiently predictable to support reliable, low-delay communications between vehicles on a highway.

  • 4.
    Bilstrup, Katrin
    et al.
    Högskolan i Halmstad, Inbyggda system (CERES).
    Uhlemann, Elisabeth
    Högskolan i Halmstad, Inbyggda system (CERES).
    Ström, Erik G.
    Chalmers.
    Bilstrup, Urban
    Högskolan i Halmstad, Inbyggda system (CERES).
    Evaluation of the IEEE 802.11p MAC method for vehicle-to-vehicle communication2008In: 68th IEEE Vehicular Technology Conference, 2008. VTC 2008-Fall: IEEE Vehicular Technology Conference (VTC) (2008), Piscataway, N.J.: IEEE Press , 2008, p. Article number 4657278-Conference paper (Refereed)
    Abstract [en]

    In this paper the medium access control (MAC) method of the upcoming vehicular communication standard IEEE 802.11p has been simulated in a highway scenario with periodic broadcast of time-critical packets (so-called heartbeat messages) in a vehicle-to-vehicle situation. The 802.11p MAC method is based on carrier sense multiple access (CSMA) where nodes listen to the wireless channel before sending. If the channel is busy, the node must defer its access and during high utilization periods this could lead to unbounded delays. This well-known property of CSMA is undesirable for time critical communications. The simulation results reveal that a specific node/vehicle is forced to drop over 80% of its heartbeat messages because no channel access was possible before the next message was generated. To overcome this problem, we propose to use self-organizing time division multiple access (STDMA) for real-time data traffic between vehicles. This MAC method is already successfully applied in commercial surveillance applications for ships (AIS) and airplanes (VDL mode 4). Our initial results indicate that STDMA outperforms CSMA for time-critical traffic safety applications in ad hoc vehicular networks.

  • 5.
    Bilstrup, Katrin
    et al.
    Högskolan i Halmstad, Inbyggda system (CERES).
    Uhlemann, Elisabeth
    Högskolan i Halmstad, Inbyggda system (CERES).
    Ström, Erik G.
    Högskolan i Halmstad, Inbyggda system (CERES).
    Bilstrup, Urban
    Högskolan i Halmstad, Inbyggda system (CERES).
    On the ability of the 802.11p MAC method and STDMA to support real-time vehicle-to-vehicle communications2009In: EURASIP Journal on Wireless Communications and Networking, ISSN 1687-1472, E-ISSN 1687-1499, Vol. 2009, no 902414, p. 1-14Article in journal (Refereed)
    Abstract [en]

    Traffic safety applications using vehicle-to-vehicle (V2V) communication is an emerging and promising area within the intelligent transportation systems (ITS) sphere. Many of these new applications require real-time communication with high reliability, meaning that packets must be successfully delivered before a certain deadline. Applications with early deadlines are expected to require direct V2V communications, and the only standard currently supporting this is the upcoming IEEE 802.11p, included in the wireless access in vehicular environment (WAVE) stack. To meet a real-time deadline, timely and predictable access to the channel is paramount. However, the medium access method used in 802.11p, carrier sense multiple access with collision avoidance (CSMA/CA), does not guarantee channel access before a finite deadline. In this paper, we analyze the communication requirements introduced by traffic safety applications, namely, low delay, reliable, real-time communications.We show by simulation of a simple, but realistic, highway scenario, that vehicles using CSMA/CA can experience unacceptable channel access delays and, therefore, 802.11p does not support real-time communications. In addition, we present a potential remedy for this problem, namely, the use of self-organizing time division multiple access (STDMA). The real-time properties of STDMA are investigated by means of the same highway simulation scenario, with promising results.

  • 6.
    Bilstrup, Katrin
    et al.
    Högskolan i Halmstad, Inbyggda system (CERES).
    Uhlemann, Elisabeth
    Högskolan i Halmstad, Inbyggda system (CERES).
    Ström, Erik G.
    Chalmers, Gothenburg.
    Bilstrup, Urban
    Högskolan i Halmstad, Inbyggda system (CERES).
    On the ability of the IEEE 802.11p and STDMA to provide predictable channel access2009In: Proceedings of the 16th World Congress on Intelligent Transport Systems (ITS), 2009, p. 10-Conference paper (Refereed)
    Abstract [en]

    Emerging traffic safety applications requiring low delay communications will need vehicle ad-hoc networks. The only communication standard currently supporting this is IEEE 802.11p. However, 802.11p uses the medium access method CSMA/CA, which has a major drawback: unbounded worst case channel access delay. We therefore propose an algorithm already in commercial use in the shipping industry: STDMA. With STDMA, nodes always get predictable channel access regardless of the number of competing nodes and the maximum delay is deterministic. In this paper we elaborated with different parameter settings for the two protocols with the aim of improving performance without altering the standards.

     

  • 7.
    Dabcevic, Kresimir
    Mälardalen University, School of Innovation, Design and Engineering.
    Evaluation of Software Defined Radio platform with respect to implementation of 802.15.4 Zigbee2011Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    With the development of powerful computational resources such as Digital Signal Processors and Field Programmable Gate Arrays, It has become possible to utilize many radio functions via software. This is the main concept of an up-and-coming technology of Software Defined Radio.

    In the Thesis, a number of platforms for implementation of Software Defined Radio has been evaluated. Platform that proved to be most suitable for the project was Ettus’ USRP N210. Using the platform, implementation of 802.15.4 Zigbee’s physical layer was done, where experiments whose outputs can later be used to compare performance with respect to "hardware radios" were performed.

    Download full text (pdf)
    Evaluation of SDR Platform with respect to implementation of 802.15.4 ZigBee
  • 8.
    Dao, Van-Lan
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Hoang, Le-Nam
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Girs, Svetlana
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Uhlemann, Elisabeth
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Defeating Jamming Using Outage Performance Aware Joint Power Allocation and Access Point Placement in Uplink Pairwise NOMA2021In: IEEE Open Journal of the Communications Society, E-ISSN 2644-125X, Vol. 2, p. 1957-1979Article in journal (Refereed)
    Abstract [en]

    In this paper, an uplink pairwise Non-Orthogonal Multiple Access (NOMA) scenario using a mobile access point (AP) or an unmanned aerial vehicle in the presence of a jamming attack is considered. To mitigate the influence of the jamming attack, a joint power allocation and AP placement design is proposed. Accordingly, closed-form expressions of the overall outage probability (OOP) and the individual outage probability (TOP) considering imperfect channel state information for each of the source nodes the AP serves, are derived over Nakagami-m fading channels using dynamic decoding order and fixed pairwise power allocation. We conduct an investigation of the effect of different parameters such as power allocation, source node placements, AP placement, target rates, and jammer location on the OOP and the IOP performance. By adapting the power allocation and the AP placement to the jamming attack, the communication reliability can be increased significantly compared to neglecting the presence of the jammer or treating the jammer as noise. Since the malicious jammer and the AP have conflicting interests in terms of communication reliability, we formulate a non-cooperative game for the two players considering their positions and the power allocation of the NOMA nodes as their strategies and the OOP as utility function. We propose using hybrid simulated annealing - greedy algorithms to address the joint power allocation and AP placement problem for the cases of both a fixed and a mobile jammer. Finally, the Nash equilibrium points are obtained and then the UAV goes directly to this position and keeps staying there to save power consumption.

  • 9.
    Dao, Van-Lan
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Tran, Hung Vinh
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Girs, Svetlana
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Uhlemann, Elisabeth
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Reliability and Fairness for CANT Communication Based on Non-Orthogonal Multiple Access2019In: 2019 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS WORKSHOPS (ICC WORKSHOPS), IEEE , 2019Conference paper (Refereed)
    Abstract [en]

    Recently, communication using unmanned aerial vehicles (LAVO as relay nodes has been considered beneficial for a number of applications. Moreover, nomorthogonM multiple access (NONIA) with users being assigned different signal passer levels while sharing the same tune-frequency domain has been found effective to enhance spectrum utilization and provide predictable access to the channel. Thus, in this paper we consider an UAV communication system with NOMA and propose a solution to find the optimal values for the user's power allocation coefficients (PA(s) needed to achieve the required levels of communication reliability. We present a closed-form expression for the PAC of each user and also propose an algori for finding the optimal altitude of the UAV required to satisfy the fairness condition for all users. Finally, we provide numerical mutinies and compare the results tar three types of communication environments.

  • 10.
    Deivard, Johannes
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Johansson, Valentin
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Diagnostics Framework for Time-Critical Control Systems in Cloud-Fog Automation2022Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Evolving technology in wireless telecommunication, such as 5G, provides opportunities to utilize wireless communication more in an industrial setting where reliability and predictability are of great concern. More capable Industrial Internet of Things devices (IIoT) are, indeed, a catalyst for Industry 4.0. Still, before the IIoT devices can be deemed capable enough, a method to evaluate the IIoT systems unobtrusively—so that the evaluation does not affect the performance of the systems—must be established. This thesis aims to answer how the performance of a distributed control system can be unobtrusively evaluated, and also determine what the state-of-the-art is in latency measurements in distributed control systems. To answer the question, a novel diagnostics method for time-critical control systems in cloud-fog automation is proposed and extensively evaluated on real-life testbeds that use 5G, WiFi 6, and Ethernet in an edge-computing topology with real control systems. The feasibility of the proposed method was verified by experiments conducted with a diagnostics framework prototype developed in this thesis. In the proposed diagnostics framework, the controller application is monitored by a computing probe based on an extended Berkeley Packet Filter program. Network communication between the controller and control target is evaluated with a multi-channel Ethernet probe and custom-made software that computes several metrics related to the performance of the distributed system. The data from the unobtrusive probes are sent to a time-series database that is used for further analysis and real-time visualization in a graphical interface created with Grafana. The proposed diagnostics method together with the developed prototype can be used as a research infrastructure for future evaluations of distributed control systems.

    Download full text (pdf)
    cfa_diagnostics_framework
  • 11.
    Ekström, Martin
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Bergblomma, Marcus
    Mälardalen University, School of Innovation, Design and Engineering.
    Lindén, Maria
    Mälardalen University, School of Innovation, Design and Engineering.
    Björkman, Mats
    Mälardalen University, School of Innovation, Design and Engineering.
    Ekström, Mikael
    Edith Cowan University, Bunbury, Australia.
    A Bluetooth Radio Energy Consumption Model for Low Duty-Cycle Applications2012In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 61, no 3, p. 609-617Article in journal (Refereed)
    Abstract [en]

    This paper presents a realistic model of the radio energy consumption for Bluetooth-equipped sensor nodes used in a low-duty-cycle network. The model is based on empirical energy consumption measurements of Bluetooth modules. This model will give users the possibility to optimize their radio communication with respect to energy consumption while sustaining the data rate. This paper shows that transmission power cannot always be directly related to energy consumption. Measurements indicate that, when the transmission power ranges from $-$5 to $+$10 dBm, the difference in consumed energy can be detected for each transmission peak in the sniff peak. However, the change is negligible for the overall energy consumption. The nonlinear behavior of the idle state for both master and slave when increasing the interval and number of attempts is presented. The energy consumption for a master node is in direct relation to the number of slaves and will increase by approximately 50% of the consumption of one slave per additional slave, regardless of the radio setting.

    Download full text (pdf)
    fulltext
  • 12.
    Folkesson, Joel
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Ky, Minh Luong
    Mälardalen University, School of Innovation, Design and Engineering.
    Impacts of Using Programmable Network Architectures on Datastreams2020Independent thesis Basic level (degree of Bachelor), 180 HE creditsStudent thesis
    Abstract [en]

    With an increase of popularity in live video streaming, there are new demands on current networks. Therefore it is interesting to explore if new architectures has what it takes. Software defined networking (SDN) is a new architecture that brings benefits in terms of control and management of networks. In this thesis we explore SDN's capabilities in terms of live streaming and put forth the question: What are the effects of using SDN-based network architecture on data streams with respect to jitter and latency? To answer this question we also need to know how to design an evaluation framework for measuring jitter and latency. We developed two iterations of a live stream, time stamping each video frame. These were used in two similar network topologies, a conventional network and an SDN-network using OpenFlow. The first iteration of the live stream depended on clock synchronization. After inconsistencies between tests we suspected that the clock synchronization was not accurate and reprogrammed the stream. The second iterations showed the same inconsistencies in latency meaning our results were inconclusive due to randomness in operative systems and inconsistencies in time stamping. This work shows several considerations to take into account when measuring latency on an application level in a network environment. Our most distinctive result shows that SDN and conventional networks have comparable jitter.

    Download full text (pdf)
    fulltext
  • 13.
    Fu, Hao
    et al.
    Tianjin Univ, Minist Educ, Key Lab Smart Grid, Tianjin 300072, Peoples R China..
    Li, Peng
    Tianjin Univ, Minist Educ, Key Lab Smart Grid, Tianjin 300072, Peoples R China..
    Fu, Xiaopeng
    Tianjin Univ, Minist Educ, Key Lab Smart Grid, Tianjin 300072, Peoples R China..
    Wang, Zhiying
    Tianjin Univ, Minist Educ, Key Lab Smart Grid, Tianjin 300072, Peoples R China..
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Wu, Jianzhong
    Cardiff Univ, Inst Energy, Sch Engn, Cardiff, Wales..
    Wang, Chengshan
    Tianjin Univ, Minist Educ, Key Lab Smart Grid, Tianjin 300072, Peoples R China..
    Asynchronous multi-rate method of real-time simulation for active distribution networksIn: IET Renewable Power Generation, ISSN 1752-1416, E-ISSN 1752-1424Article in journal (Refereed)
    Abstract [en]

    The real-time simulation of active distribution networks (ADNs) can provide an accurate insight into transient behaviours, but faces challenges in simulation efficiency and flexibility brought by larger system scales and wider time-scale ranges. This paper presents an asynchronous multi-rate (AMR) method and design for the real-time simulation of large-scale ADNs. In the proposed method, the entire ADN was decoupled into different subsystems according to accuracy requirements, and optimized time-steps were allocated to each subsystem to realize a fully distributed simulation. This not only alleviated the time-step coordination problem existing in multi-rate real-time simulations, but also enhanced the flexible expansion capabilities of the real-time simulator. To realize the AMR real-time simulation, a multi-rate interfacing method, synchronization mechanism, and data communication strategy are proposed in this paper, and their hardware design is also presented in detail. A modified IEEE 123-node system with photovoltaics and wind turbine generators was simulated on a 3 field-programmable gate arrays (FPGAs)-based AMR real-time simulator. The real-time results were captured by the oscilloscope and verified with PSCAD/EMTDC, which demonstrated the superiority in simulation flexibility and accuracy compared with the synchronous multi-rate (SMR) method.

  • 14.
    Gore, Rahul Nandkumar
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Investigating Software-based Clock Synchronization for Industrial Networks2021Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    A rising level of industrialization and advances in Industry 4.0 have resulted in Industrial Internet of Things (IIoT) gaining immense significance in today’s industrial automation systems. IIoT promises to achieve improved productivity, reliability, and revenues by connecting time-constrained embedded systems to “the Internet”. New opportunities bring with them challenges, and in particular for industrial networks, massively interconnected IIoT devices communicating in real-time,  require synchronized operation of devices for the ordering of information collected throughout a  network. Thus,   a   time or clock synchronization service that aligns the devices’ clocks in the network to ensure accurate timestamping and orderly event executions, has gained great importance. Achieving adequate clock synchronization in the industrial domain is challenging due to heterogeneous communication networks and exposure to harsh environmental conditions bringing interference to the communication networks. The investigative study based on existing literature and the envisioned architecture of the future industrial automation system unveils that the key requirements for future industrial networks are to have a cost-effective, accurate, scalable, secured, easy to deploy and maintain clock synchronization solution. Today’s industrial automation systems employ clock synchronization solutions from a wide plethora of hardware and software based solutions. The most economical, highly scalable, maintainable software-based clock synchronization means are best candidates for the identified future requirements as their lack in accuracy compared to hardware solutions could be compensated by predictive software strategies.

     Thus, the thesis’s overall goal is to enhance the accuracy of software-based clock synchronization in heterogeneous industrial networks using predictable software strategies. The first step towards developing an accurate clock synchronization for heterogeneous industrial networks with real-time requirements is to investigate communication parameters affecting time synchronization accuracy. Towards this goal, we investigated actual industrial network data for packet delay profiles and their impact on clock synchronization performance.  We further analyzed wired and wireless local area networks to identify key network parameters for clock synchronization and proposed an enhanced clock synchronization algorithm CoSiNeT for field IoT devices in industrial networks. CoSiNeT matches well with state-of-the-practice SNTP and state-of-the-art method SPoT in good network conditions in terms of accuracy and precision;  however,  it outperforms them in scenarios with degrading network conditions.

    Download full text (pdf)
    fulltext
  • 15.
    Hassani, Abtin
    Mälardalen University, School of Innovation, Design and Engineering.
    Designing a fault tolerant and secure network core for inter-organization communication2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Service providers which provide services within customers’ networks often deal with the issue of needing to use a large number of VPN accounts and RSA tokens to access customers’ networks. One service provider (SP) has solved this by setting up an inter-organizational communication network (IOCN) to facilitate access to customer places systems. This system has out grown its original setup.  Research on network architectures is abundant but there is very limited research focusing on IOCNs. The aim of this thesis has been to contribute to the lack of that research by intending to redesign the above mentioned IOCN with focus on ensuring network security and fault tolerance. This was done by analyzing the existing IOCN, evaluating its flaws with regards to network security and fault tolerance and finally suggesting a new setup based on the original infrastructure. The solution has been generalized to be adaptable to the needs of any service provider. The infrastructure has been setup with a cascading firewall structure increasing security by using generalized rules on the outer firewalls and specifying rules further in to the network.

    Download full text (pdf)
    fulltext
  • 16.
    Henriksson, Johannes
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Magnusson, Alexander
    Mälardalen University, School of Innovation, Design and Engineering.
    Impact of using cloud-based SDNcontrollers on the networkperformance2019Independent thesis Basic level (university diploma), 180 HE creditsStudent thesis
    Abstract [en]

    Software-Defined Networking (SDN) is a network architecture that differs from traditionalnetwork planes. SDN has tree layers: infrastructure, controller, and application. Thegoal of SDN is to simplify management of larger networks by centralizing control into thecontroller layer instead of having it in the infrastructure. Given the known advantages ofSDN networks, and the flexibility of cloud computing. We are interested if this combinationof SDN and cloud services affects network performance, and what affect the cloud providersphysical location have on the network performance. These points are important whenSDN becomes more popular in enterprise networks. This seems like a logical next step inSDN, centralizing branch networks into one cloud-based SDN controller. These questionswere created with a literature studies and answered with an experimentation method. Theexperiments consist of two network topologies both locally hosted SDN (baseline) and cloudhosted SDN. The topology used Zodiac FX switches and Linux hosts. The following metricswas measured: throughput, latency, jitter, packet loss, and time to add new hosts. Theconclusion is that SDN as a cloud service is possible and does not significantly affect networkperformance. One limitation with this thesis was the hardware, resulting in big fluctuationin throughput and packet loss.

    Download full text (pdf)
    fulltext
  • 17.
    Hoang, Le-Nam
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Uhlemann, Elisabeth
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Jonsson, M.
    School of Information Technology, Halmstad University, Halmstad, Sweden.
    Relay Grouping to Guarantee Timeliness and Reliability in Wireless Networks2019In: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 23, no 9, p. 1661-1664, article id 8737952Article in journal (Refereed)
    Abstract [en]

    Relaying can increase reliability, range, or throughput. In many cyber-physical systems (CPS), relaying is used to maximize reliability before a given deadline. Since concurrent transmissions are not supported by most CPS, time-division multiple access (TDMA) is typically used. However, a major drawback of relaying in TDMA is that pre-allocated time-slots are wasted if their respective transmitters do not have any correctly received packet to relay. Therefore, in this letter, we propose a novel relay grouping scheme to overcome this drawback. Numerical results show that the proposed scheme significantly enhances the reliability while guaranteeing the deadline for each message. 

  • 18.
    Huu, Tung Pham
    et al.
    NUCE, Fac Informat Technol, 55 Giai Phong Rd, Hanoi, Vietnam.
    Quach, Truong Xuan
    TNU Univ Informat & Commun Technol, Ho Chi Minh City, Vietnam.
    Tran, Hung Vinh
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Zepernick, Hans-Jurgen
    Blekinge Inst Technol, Karlskrona, Sweden..
    Sibomana, Louis
    Univ Rwanda, Kigali, Rwanda..
    On Proactive Attacks for Coping With Cooperative Attacks in Relay Networks2017In: 2017 23RD ASIA-PACIFIC CONFERENCE ON COMMUNICATIONS (APCC): BRIDGING THE METROPOLITAN AND THE REMOTE, IEEE , 2017, p. 220-225Conference paper (Refereed)
    Abstract [en]

    Cooperative communications in which relays assist the transmission of signals from source to destination offer extended radio coverage and improved link reliable. However, transmitting signals with the help of a relay network may also open additional avenues for eavesdropper to overhear confidential information. Further, as jammers and eavesdroppers may cooperate to attack the relay network, offering secure communications becomes a challenging problem. To cope and reduce the effect of such cooperative attacks, we propose a proactive attack scheme in which the legitimate users generate jamming signals in an attempt to counteract such hostile cooperative attacks. In order to assess the security performance of the proactive attack scheme compared to a non-protection scheme, an analytical expression of the secrecy outage probability is derived. Numerical results for different system settings are provided showing that the proactive attack scheme can indeed significantly improve the security performance of the considered relay networks.

  • 19.
    Jiang, X.
    et al.
    Jilin Jianzhu University, Changchun, 130118, China.
    Song, X.
    Harbin Institute of Technology, Harbin, 150006, China.
    Zhao, H.
    Jilin Jianzhu University, Changchun, 130118, China.
    Zhang, Haoran
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. LocationMind Inc, 3-5-2 Iwamotocho, Chiyoda-ku, Tokyo, 101-0032, Japan; The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba, 277-8568, Japan.
    Rural tourism network evaluation based on resource control ability analysis: A case study of Ning’an, China2021In: Land, E-ISSN 2073-445X, Vol. 10, no 4, article id 427Article in journal (Refereed)
    Abstract [en]

    Organization of rural tourism resources is important for optimizing rural land use based on rational resource classification. Quantitative analysis was performed to evaluate the resource control ability of rural tourism networks. This was achieved by determining the resource control relationship and assessing the structure of the rural tourism network. The ability of resource control was analyzed via resource abstraction, which included the extraction of resource nodes and corridors, control scope analysis, and network structure level evaluation. The proposed approach was applied to the Ning’an in Heilongjiang Province, China, and proved to be effective for exploring the network degree and development trends in rural tourism resources. By examining the resource control ability, the spatial characteristics and development trend in rural tourism networks were quantitatively analyzed, especially the connection mode of key tourism resources, network structure analysis, and resource linking ability. The core resources showed a lack of outward ability in the network, and the secondary resource expansion ability was limited. Via resource control ability analysis, this study focused on areas with rich tourism but an unbalanced spatial structure, combining the directional characteristics of the network to provide suggestions for the optimization rural tourism resources network in other regions of the world. 

  • 20.
    Kunert, Kristina
    et al.
    Högskolan i Halmstad, Centrum för forskning om inbyggda system (CERES).
    Uhlemann, Elisabeth
    Högskolan i Halmstad, Centrum för forskning om inbyggda system (CERES).
    Jonsson, Magnus
    Högskolan i Halmstad, Centrum för forskning om inbyggda system (CERES).
    Enhancing reliability in IEEE 802.11 based real-time networks through transport layer retransmissions2010In: 2010 International Symposium on Industrial Embedded Systems (SIES), 2010, p. 146-155Conference paper (Refereed)
    Abstract [en]

    As the number of application areas for wireless technologies grows, the need for providing both predictable and reliable communication over wireless networks becomes apparent. Cooperative embedded systems for industrial automation are one example of systems with these needs. Previously, we developed a framework for reliable real-time communication in a single-hop wireless network with a logical star topology. The framework was placed on top of IEEE 802.15.4 and combines transport layer retransmissions with real-time analysis admission control. IEEE 802.15.4 was selected due to its advantageous energy saving techniques, making it an interesting choice for wireless sensor networks in industrial contexts. However, its achievable data rate is rather low, especially when voice or video for industrial surveillance and monitoring need to be transferred. Hence, we adapt our framework to fit the IEEE 802.11 standard and evaluate its performance using a data traffic model from industrial control and surveillance systems. The performance of the framework is evaluated in terms of network utilization, message error rate and delay distribution using theoretical analysis as well as computer simulations.

     

  • 21.
    Kunert, Kristina
    et al.
    Högskolan i Halmstad, Centrum för forskning om inbyggda system (CERES).
    Uhlemann, Elisabeth
    Högskolan i Halmstad, Centrum för forskning om inbyggda system (CERES).
    Jonsson, Magnus
    Högskolan i Halmstad, Centrum för forskning om inbyggda system (CERES).
    Predictable real-time communications with improved reliability for IEEE 802.15.4 based industrial networks2010In: 2010 8th IEEE International Workshop on Factory Communication Systems (WFCS), 2010, p. 13-22Conference paper (Refereed)
    Abstract [en]

    Emerging industrial applications requiring reliable wireless real-time communications are numerous. Using existing standards such as IEEE 802.15.4 is essential for reasons of interoperability and cost efficiency. However, since 802.15.4 is unable to provide predictable channel access, real-time guarantees cannot be given. Further, the noisy wireless channel makes reliable communications particularly challenging. By adding a deterministic medium access method and a transport protocol with a truncated retransmission scheme to 802.15.4, we jointly enforce reliability and predictability. We evaluate our solution analytically by real-time schedulability analysis including retransmissions, and by computer simulations. We show that the message error rate can be improved by several orders of magnitude while keeping the utilization penalty at reasonable levels.

  • 22.
    Lööf, Mattias
    Mälardalen University, School of Innovation, Design and Engineering.
    Morgondagens Nätverksadministratör2018Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Datornätverken håller på att förändras i grunden där det traditionella sättet med enheter som konfigureras en och en byts mot ett mer automatiserat sätt. Denna nya typ av nätverk benämns ofta ”Software Defined Network (SDN)” och använder sig av en centraliserad Controller som styr nätverket. För automatisering och användning av applikationer inom SDN används Application Programming Interface(API).Denna nya typ av nätverk förändrar kraven som ställs på nätverksadministratörer och skapar nya möjligheter. Några av dessa möjligheter skapas genom öppnande av API:er där applikationer nu kan integreras in i nätverket. Detta gör att nätverksadministratörer även behöver ha kunskap kring API:er och förstå vilka möjligheter de skapar i nätverket. Rapportens syfte var att redogöra för dessa genom följande frågeställningar:

    1. Vilken kompetens kommer att krävas av morgondagens nätverksadministratör (två- till fyra-års sikt)

    2. Hur kommer det programmerbara (API) nätverket att förändra sättet att etablera nya tjänster/applikationer i företagens nätverk?

    3. Hur kan dessa applikationer implementeras på ett nytt och automatiserat sätt?

    För att besvara frågeställningarna användes en exempelteknik ”Cisco Software Defined Access (SDA)” som är en ny SDN-lösning släppt på marknaden under 2017.Resultatet från frågeställning ett visade att kunskap kring nya protokoll som implementeras för att lösa utmaningen kring segmentering, mobilitet och säkerhet i nätverk blir viktigt. Exempel på detta var protokollen LISP och VXLAN som tillsammans med ett overlay-lager skapar dessa möjligheter. Resultatet visade även att kunskap kring hur Northbound och Southbound Interfaces används för styrande av nätverksenheterna och integration mellan applikationer blir en viktig kompetens.Resultatet för frågeställning två visade hur API:er förenklar utvecklingen av tredjeparts applikationer, något som gör att användningen och utvecklingen av applikationer kommer öka i allt snabbare takt. Slutligen visade resultatet exempel på hur en brandväggsapplikation kan förenkla och effektivisera arbetet för en nätverksadministratör.

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  • 23.
    Magnusson, Alexander
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Pantzar, David
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Integrating 5G Components into a TSN Discrete Event Simulation Framework2021Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    TSN has for many years been the staple of reliable communication over traditional switched Ethernet and, has been used to advance the industrial automation sector. However, TSN is not mobile, which is needed to fully enable Industry 4.0. The development of 5G and its promised URLLC combined with TSN would give both a mobile and reliable heterogeneous network. The 3GPP has suggested different designs for a 5G and TSN integration. This thesis investigates the different proposed integration designs. Besides the integration design, one of the most essential steps towards validity of the integration is to evaluate the TSN-5G networks based on simulation. Currently, this simulation environment is missing. The investigation in this thesis shows that the most exhaustive work had been done on the Logical TSN Bridge design for simulators, such as the ones based on OMNeT++. Capabilities of the simulator itself are also investigated, where aspects such as the lack of a 5G medium and clock synchronization are presented. In this thesis, we implement the 5G-TSN component that results in a translator which sets different 5G channel parameters depending on the Ethernet packet's priority and its corresponding value. To verify the functionality of the translator that is developed within the simulator, it is tested in a use case inspired by the vehicle industry, containing both TSN and 5G devices. Results from the use case indicate that the translation is performed correctly.

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  • 24.
    Morsi Mahmod, Mohamed
    et al.
    University of Twente, Sweden.
    Khalil, Issam
    Ericsson AB, Branch Office Sudan, Sudan.
    Uhlemann, Elisabeth
    Högskolan i Halmstad, Sweden.
    Nygren, Niclas
    Volvo Technology Corporation, Transport, Information and Communication, Sweden.
    Wireless strategies for future and emerging ITS applications2008In: 15th World Congress on Intelligent Transport Systems: New York, USA, November 16-20, 2008 : ITS connections, saving time, saving lives, New York: World Congress on Intelligent Transport Systems (ITS) , 2008, p. 12-Conference paper (Refereed)
    Abstract [en]

    Within the Intelligent Transportation Systems (ITS) field, many applications of a diverse nature are considered and thus their communication requirements differ significantly. This makes it difficult for one wireless carrier to support all or most of these applications. Therefore, we have complied a list of communication requirements for future ITS applications and used it to analyze different ITS applications as well as different wireless carriers. Accordingly, the applications can be grouped into different requirements profiles with recommended wireless carriers assigned to each profile. The concept of profiling can also be used to classify the applications according to their non-technical requirements and hence accelerate their future deployment by encouraging involved stakeholders to make the most common requirements available. It can also be useful when developing a roadmap for deployment of future ITS applications defining which application will most likely be implemented first.

  • 25.
    Satka, Zenepe
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Alvarez Vadillo, Ines
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. Universitat de les Illes, Balears, Spain.
    Ashjaei, Seyed Mohammad Hossein
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Mubeen, Saad
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Work in Progress: A Centralized Configuration Model for TSN-5G Networks2022In: IEEE International Conference on Emerging Technologies and Factory Automation, ETFA, Institute of Electrical and Electronics Engineers Inc. , 2022, Vol. 2022-SeptemberConference paper (Refereed)
    Abstract [en]

    The integration of Time-Sensitive Networks (TSN) with 5G cellular networks requires a defined architecture for network configuration and management. Although 3GPP specifications provide necessary means for the TSN-5G integration, the operation of such converged TSN-5G network remains an open challenge for the research community. To address this challenge, this paper presents the ongoing work in developing a centralized architectural model to configure the TSN-5G network, and forward traffic from TSN to 5G and vice-versa. The proposed architectural model uses knowledge of the traffic characteristics to carry out a more accurate mapping of quality of service attributes between TSN and 5G.

  • 26.
    Satka, Zenepe
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Pantzar, David
    Mälardalen University.
    Magnusson, Alexander
    Mälardalen University.
    Ashjaei, Seyed Mohammad Hossein
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Fotouhi, Hossein
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Sjödin, Mikael
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Daneshtalab, Masoud
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Mubeen, Saad
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Developing a Translation Technique for Converged TSN-5G Communication2022In: IEEE International Workshop on Factory Communication Systems - Proceedings, WFCS, Institute of Electrical and Electronics Engineers Inc. , 2022, p. 103-110Conference paper (Refereed)
    Abstract [en]

    Time Sensitive Networking (TSN) is a set of IEEE standards based on switched Ethernet that aim at meeting high-bandwidth and low-latency requirements in wired communication. TSN implementations typically do not support integration of wireless networks, which limits their applicability to many industrial applications that need both wired and wire-less communication. The development of 5G and its promised Ultra-Reliable and Low-Latency Communication (URLLC) in-tegrated with TSN would offer a promising solution to meet the bandwidth, latency and reliability requirements in these industrial applications. In order to support such an integration, we propose a technique to translate the traffic between TSN and 5G communication technologies. As a proof of concept, we implement the translation technique in a well-known TSN simulator, namely NeSTiNg, that is based on the OMNeT ++ tool. Furthermore, we evaluate the proposed technique using an automotive industrial use case. 

  • 27.
    Sjöberg, Katrin
    et al.
    Högskolan i Halmstad, Inbyggda system (CERES).
    Karedal, Johan
    Dept. of Electrical and Information technology, Lund University.
    Moe, Marie
    Q-Free ASA, Trondheim, Norway.
    Kristiansen, Øyvind
    Q-Free ASA, Trondheim, Norway.
    Søråsen, Runar
    Q-Free ASA, Trondheim, Norway.
    Uhlemann, Elisabeth
    Högskolan i Halmstad, Inbyggda system (CERES).
    Tufvesson, Fredrik
    Dept. of Electrical and Information technology, Lund University.
    Evensen, Knut
    Q-Free ASA, Trondheim, Norway.
    Ström, Erik
    Dept. of Signals and Systems, Chalmers University of Technology.
    Measuring and using the RSSI of IEEE 802.11p2010Conference paper (Refereed)
    Abstract [en]

    The scalability of intelligent transport systems (ITS) applications is difficult to test in a field operational test (FOT) due to the high number of ITS equipped vehicles required. Therefore, computer simulations for evaluating different wireless communication technologies for ITS different applications can serve as a complement. In this paper we present results from lab measurements conducted on the CVIS hardware platform equipped with the upcoming standard IEEE 802.11p. We have measured the packet error rate versus the signal-to-noise ratio (SNR) for different packet lengths. This lab measurement is the first step towards an outdoor measurement campaign which also considers interference. The outdoor measurements will then be fed into a computer simulator together with a realistic channel model for evaluating the scalability of VANETs in a highway scenario.

  • 28.
    Sjöberg, Katrin
    et al.
    Högskolan i Halmstad, Inbyggda system (CERES).
    Uhlemann, Elisabeth
    Högskolan i Halmstad, Inbyggda system (CERES).
    Ström, Erik G.
    Chalmers Technical University, Gothenbur, Sweden.
    Delay and interference comparison of CSMA and self-organizing TDMA when used in VANETs2011In: IWCMC 2011: IWCMC 2011 - 7th International Wireless Communications and Mobile Computing Conference / [ed] IEEE, New York, NY: IEEE Press , 2011, p. 1488-1493Conference paper (Refereed)
    Abstract [en]

    IEEE 802.11p is the proposed wireless technology for communication between vehicles in a vehicular ad hoc network (VANET) aiming to increase road traffic safety. In a VANET, the network topology is constantly changing, which requires distributed self-organizing medium access control (MAC) algorithms, but more importantly the number of participating nodes cannot be restricted. This means that MAC algorithms with good scalability are needed, which can fulfill the concurrent requirements on delay and reliability from road traffic safety applications. The MAC method of IEEE 802.11p is a carrier sense multiple access (CSMA) scheme, which scales badly in terms of providing timely channel access for a high number of participating nodes. We therefore propose using another MAC method: selforganizing time division multiple access (STDMA) with which all nodes achieve timely channel access regardless of the number of participating nodes. We evaluate the performance of the two MAC methods in terms of the MAC-to-MAC delay, a measure which captures both the reliability and the delay of the delivered data traffic for a varying number of vehicles. The numerical results reveal that STDMA can support almost error-free transmission with a 100 ms deadline to all receivers within 100 m, while CSMA suffers from packet errors. Moreover, for all considered cases, STDMA offers better reliability than CSMA.

  • 29.
    Sjöberg-Bilstrup, Katrin
    et al.
    Högskolan i Halmstad, Inbyggda system (CERES).
    Uhlemann, Elisabeth
    Högskolan i Halmstad, Inbyggda system (CERES).
    Ström, Erik G.
    Dept. Signals and Systems, Chalmers University of Technology.
    Scalability issues of the MAC methods STDMA and CSMA of IEEE 802.11p when used in VANETs2010In: 2010 IEEE International Conference on Communications Workshops (ICC), 2010, p. Article number 5503941-Conference paper (Refereed)
    Abstract [en]

    Position messages will be the foundation for many emerging traffic safety applications based on wireless communications. These messages contain information about the vehicle’s position, speed, direction, etc. and are broadcasted periodically by each vehicle. The upcoming IEEE 802.11p standard, intended for vehicle unpredictable behavior of its medium access control (MAC) scheme, which imply that traffic safety applications cannot be supported satisfactorily when the network load increases. We study the MAC mechanism within IEEE 802.11p being a carrier sense multiple access (CSMA) algorithm and compare it with a self-organizing time division multiple access (STDMA) scheme when used for broadcasting periodic position messages in a realistic highway scenario. We investigate their scalability in terms of the number of vehicles that the VANET can support using metrics such as channel access delay, probability of concurrent transmissions and interference distance. The results show that STDMA outperforms CSMA of 802.11p even when the network is not saturate

     

  • 30.
    Strandén, Lars
    et al.
    SP Technical Research Institute of Sweden, Borås, Sweden.
    Uhlemann, Elisabeth
    Volvo Technology Corporation, Gothenburg, Sweden.
    Ström, Erik G.
    Chalmers University of Technology, Gothenburg, Sweden.
    State of the art survey of wireless vehicular communication projects2008In: 15th World Congress on Intelligent Transport Systems: New York, November 16-20, 2008 : proceedings : ITS connections: saving time, saving lives, World Congress on Intelligent Transport Systems (ITS) , 2008, p. 10-Conference paper (Refereed)
    Abstract [en]

    In this paper the results of a state of the art survey, using publicly available information, are presented. The scope of the survey concerns projects that include wireless communication vehicle-to-vehicle and vehicle-to-infrastructure. Since there is a vast amount of information available, a specific methodology has to be developed and applied. This paper presents such a methodology which is based on a matrix representation that enables the definition of specific metrics. These metrics can then be used for further evaluation. The objectives of this work are threefold; to gather relevant project information, to define and apply a methodology for handling this information, and to compare and draw some general conclusions about the nature of projects carried out in Europe, USA and Japan.

  • 31.
    Uhlemann, Elisabeth
    Högskolan i Halmstad, Inbyggda system (CERES).
    Communication requirements of emerging cooperative driving systems2011In: Digest of Technical Papers - IEEE International Conference on Consumer Electronics / [ed] Institute of Electrical and Electronics Engineers, Piscataway, N.J.: IEEE Computer Society , 2011, p. 281-282Conference paper (Refereed)
    Abstract [en]

    Traffic safety applications relying on cooperative systems are currently being considered by several research projects worldwide. An important question is if existing wireless technologies can meet the communication requirements from this emerging field of applications? Part of the answer to this question is that the communication requirements depend on what is actually communicated and how this information is used by and presented to the driver. The data traffic from realizations based on "cooperative awareness" or on "hazard warnings" are very different. This article discusses the communication requirements of some typical traffic safety applications and how these requirements are affected by different realizations.

  • 32.
    Uhlemann, Elisabeth
    et al.
    Högskolan i Halmstad, Inbyggda system (CERES).
    Nygren, Niclas
    Volvo Technology, Sweden.
    Cooperative systems for traffic safety: Will existing wireless access technologies meet the communications requirements?2009In: Proceedings of the 16th World Congress on Intelligent Transport Systems (ITS), Stockholm: World Congress on Intelligent Transport Systems (ITS) , 2009, p. 8-Conference paper (Refereed)
    Abstract [en]

    Traffic safety applications relying on cooperative systems are currently being considered by several research projects worldwide. An important question is if existing wireless technologies can meet the communication requirements from this emerging field ofvapplications? Part of the answer to the question is that the communication requirements depend on implementation. The data traffic from realizations based on “cooperative awareness” or on “hazard warnings” are very different. This article discusses the communication requirements of some typical traffic safety applications, how these requirements are affected by different realizations and finally what is required from a wireless access technology to support these applications.

  • 33.
    Uhlemann, Elisabeth
    et al.
    Högskolan i Halmstad, Inbyggda system (CERES).
    Willig, Andreas
    Technical University of Berlin.
    Hard decision packet combining methods for industrial wireless relay networks2008In: Second International Conference on Communications and Electronics, 2008. ICCE 2008, Piscataway, N.J.: IEEE Press , 2008, p. 104-108Conference paper (Refereed)
    Abstract [en]

    We consider wireless relay networks for use in industrial applications with strict requirements on both reliable and timely communications. In most cases commercially available transceivers must be used, which implies that only hard decision detector outputs are available. Since relay networks typically use retransmissions of erroneous packets, packet combining methods have the potential to increase the information reliability without excessive delay. We evaluate three different hard decision packet combining methods for different placement of the source, the relay node and the destination. Packet combining can in general be improved with knowledge of the current channel state information, which, however, is often not available. In this paper we find a packet combining method which does not use channel state information but which delivers similar performance as the scheme that has knowledge of the channel state.

  • 34.
    Uhlemann, Elisabeth
    et al.
    Högskolan i Halmstad, Inbyggda system (CERES).
    Willig, Andreas
    Technical University of Berlin.
    Joint design of relay and packet combining schemes for wireless industrial networks2008In: IEEE Vehicular Technology Conference 2008, IEEE Press , 2008, p. 2441-2445Conference paper (Refereed)
    Abstract [en]

    Wireless industrial networks differ in many respects from other types of wireless networks. In particular, since many applications impose tight real-time and reliability requirements at the same time, and packet sizes tend to be small. In this paper we design a simple and practically implementable protocol in which relaying and packet combining work together to improve the probability that packets are delivered within a prescribed deadline over fading channels. The results indicate that such a combination can be fruitfully employed in wireless industrial networks.

  • 35.
    Valieva, Inna
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Björkman, Mats
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Åkerberg, Johan
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Ekström, Mikael
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Shashidhar, Bharath
    Voitenko, Iurii
    Electronics Development Wireless P2P Technologies, Falun, Sweden.
    AUTONOMOUS DETECTION OF VACANT FREQUENCY BANDS FOR COGNITIVE RADIOManuscript (preprint) (Other academic)
    Abstract [en]

    This This paper is focused on thea utonomous detection of the vacant frequency channels in the wide observation band of 60MHz. Vacant channel detection has been modeled as a binary hypothesis testing problem. Three signal detection algorithms including energy detection, wavelets, and cyclostationary have been tested and evaluated in terms of accuracy.Testing has been performed offline on the data samples collected during the controlled experiment. Data samples consisting of AWGN noise and FSK, BPSK, QPSK modulated signals have been generated using thehardware signal generator and received on our targetapplication's receiver (AD9364) front end as a time domain complex signal. The optimal threshold value hasbeen determined as an optimal value between the hitrate and the false positive rate. The highest accuracy of 91.0% has been reached the wavelet transform feature extraction, energy detection has shown 86.4% accuracy. Cyclostationary detection has shown no distinguishable difference in the spectrum correlation values calculatedfor the AWGN noise sample and samples containing BPSK and 2FSK modulated signals captured with -20dB power.

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  • 36.
    Valieva, Inna
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Björkman, Mats
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Åkerberg, Johan
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Ekström, Mikael
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Voitenko, Iurii
    Electronics Development Wireless P2P Technologies Falun, Sweden .
    Blind symbol rate estimation for cognitive radio using wavelet transform and deep learning for fsk modulated digital signalsManuscript (preprint) (Other academic)
    Abstract [en]

    This paper is focused on the blind symbol rate estimation for the digital FSK modulated signals. Symbol rate estimation is based on the classification between three symbol rate classes: 10, 100 and 1000K Symbol/second using the scalogram images obtained from time-frequency analysis performed using the continuous wavelet transform with Morse wavelet. Pretrained deep learning AlexNet has been transfer learned to classify between symbol rate classes. Training, testing and validation data sets have been composed from the artificial data generated using Bernoulli binary random signal generator modulated into FSK signal corrupted by additive white Gaussian noise (AWGN) noise with SNR ranging from 1 to 30 dB. The average classification accuracy during validation has reached 99.7% and during testing 100 % and 96.3 % for the data sets with SNR 25-30 dB and 20-25 dB respectively. Proposed algorithm has been compared with cyclostationary and has shown improved classification accuracy especially in conditions of low SNR. Central frequency estimation has been performed using a modified periodogram estimate of the power spectral density with a rectangular window. 

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  • 37.
    Valieva, Inna
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Björkman, Mats
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Åkerberg, Johan
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Ekström, Mikael
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Voitenko, Iurii
    Electronics Development Wireless P2P Technologies AB, Falun, Sweden.
    Multiple Machine Learning Algorithms Comparison for Modulation Type Classification for Efficient Cognitive Radio2019In: MILCOM 2019 - 2019 IEEE Military Communications Conference (MILCOM), Norfolk, USA: IEEE, 2019, article id 9020735Conference paper (Refereed)
    Abstract [en]

    In this paper the potential of improving channel utilization by signal modulation type classification based on machine learning algorithms has been studied. The classification has been performed between two popular digital modulations: BPSK and FSK in target application. Classification was based on three features available on a popular software defined radio transceiver AD9361: In-phase and quadrature components of the digital time domain signal and signal-to-noise ratio (SNR), measured as RSSI value. Data used for network training, validation and testing was generated by the Simulink model consisting mainly of modulator, transceiver AD9361 and AWGN to generate the signal with SNR ranging from 1 to 30 dB. Twenty-three supervised machine learning algorithms including K-nearest neighbor, Support Vector Machines, Decision Trees and Ensembles have been studied, evaluated and verified against the target application's requirements in terms of classification accuracy and speed. The highest average classification accuracy of 86.9% was achieved by Support Vector Machines with Fine Gaussian kernel, however with demonstrated classification speed of 790 objects per second it was considered unable to meet target application's real-time operation requirement of 2000 objects per second. Fine Decision Trees and Ensemble Boosted Trees have shown optimal performance in terms of both reaching classification speed of 1200000 objects per second and average classification accuracy of 86.0% and 86.3% respectively. Classification accuracy has been also studied as a function of SNR to determine the most accurate classifier for each SNR level. At the target application's demodulation threshold of 12 dB 87.0% classification accuracy has been observed for the Fine Decision Trees, 87.5% for both Fine Gaussian SVM and Coarse KNN. At SNR higher than 27 dB Fine Trees, Coarse KNN have reached 97.5% classification accuracy. The effects of data set size and number of classification features on classification speed and accuracy have been studied too.

  • 38.
    Valieva, Inna
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Voitenko, Iurii
    Research and Development, Wireless P2P Technologies, Falun, Sweden.
    Björkman, Mats
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Åkerberg, Johan
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Ekström, Mikael
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Blind Symbol Rate Estimation Using Wavelet Transform and Deep Learning for FSK Modulated Signals2022In: 2022 International Conference on Advanced Technologies for Communications (ATC), 2022Conference paper (Refereed)
    Abstract [en]

    This paper is focused on the blind symbol rate estimation for the digital FSK modulated signals, based on the classification between three symbol rate classes: 10, 100, and 1000 KSymbol/second using the scalogram images obtained from continuous wavelet transform with Morse wavelet. Pretrained deep learning AlexNet has been transfer learned to classify between symbol rate classes. Training, testing, and validation data sets have been composed of the artificial data generated using Bernoulli binary random signal generator modulated into FSK signal corrupted by additive white Gaussian noise (AWGN) noise with SNR ranging from 1 to 30 dB. Training and validation data sets have been augmented to obtain twice more extensive data set i.e 1800 scalogram images, compared to the original size of 900 samples. The average classification accuracy during validation has reached 99.7 % and during testing 100 % and 96.3 % for the data sets with SNR 25–30 dB and 20–25 dB respectively. The proposed algorithm has been compared with cyclostationary and has shown improved classification accuracy, especially in conditions of low SNR.

  • 39.
    Wang, W.
    et al.
    Computer Science Department, University of Pittsburgh, Pittsburgh, PA, United States.
    Mosse, D.
    Computer Science Department, University of Pittsburgh, Pittsburgh, PA, United States.
    Papadopoulos, Alessandro
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Packet priority assignment for wireless control systems of multiple physical systems2019In: Proceedings - 2019 IEEE 22nd International Symposium on Real-Time Distributed Computing, ISORC 2019, Institute of Electrical and Electronics Engineers Inc. , 2019, Vol. 107, p. 143-150Conference paper (Refereed)
    Abstract [en]

    Wireless control systems (WCSs) have gained much attention lately, due to their easy deployment and flexibility compared to wired control systems. However, this comes at the cost of possibly increased network delay and packet losses, that can significantly impact the control system performance, and possibly its stability. Such problems become even more relevant if the network is shared among different control systems, and thus becomes a scarce resource, like in Industrial Internet of Things applications. In this paper, we describe how to assign packet priorities dynamically when there are many physical systems sharing a given network, aiming at minimizing the performance degradation of the WCS. Towards that, we present a network model including both delay and packet losses, both of which are very important for the control system performance. Our solution is evaluated over two different use cases to show the generality of the approach: the WCS for a set of inverted pendula, and the WCS for small modular reactors in a nuclear power plant. The results show that the proposed approach allows for a more stable performance even in presence of highly nonlinear systems, sensitive to time-varying delays, as well as in presence of high network interference.

  • 40.
    Willig, Andreas
    et al.
    Technische Universitt Berlin, Berlin, Germany.
    Uhlemann, Elisabeth
    Högskolan i Halmstad, Inbyggda system (CERES).
    PRIOREL-COMB: A protocol framework supporting relaying and packet combining forwireless industrial networking2008In: WFCS 2008: 2008 IEEE International Workshop on Factory Communication Systems : proceedings : May 21st-23rd, 2008, Steigenberger Hotel de Saxe, Dresden, Germany / [ed] Gianluca Cena and Françoise Simonot-Lion, Piscataway, NJ: IEEE Press , 2008, p. 45-54Conference paper (Refereed)
    Abstract [en]

    The PRIOREL-COMB framework presented here integrates support for relaying and packet combining into wireless industrial networks. The selection of suitable relay nodes is made using distributed algorithms which includes different eligibility tests as well as different priority assignments. The framework improves performance in terms of probability to successfully deliver packets before their deadline and it can be implemented on top of commercial transceivers without modification of the physical layer. This class of protocols will therefore be a valuable addition to future wireless industrial communication systems.

  • 41.
    Yusuf, Balqis
    Mälardalen University, School of Innovation, Design and Engineering.
    Minimizing the clock drift in partially synchronized heterogeneous TSN networks2023Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The new generation of embedded systems will increase interaction between the environment, people, and autonomous devices. This will increase their need for communication, particularly in meeting real-time requirements. To address the real-time requirements of embedded systems, a communication network capable of providing high bandwidth, low latency, and deterministic behaviour is necessary. Time-Sensitive Networking (TSN) was developed by the IEEE 802.1 TSN Task Group and is a set of standards providing deterministic service over standard Ethernet and is an attractive option for achieving this. TSN leverages the advantages of IEEE Ethernet standards, including low hardware cost, high bandwidth, and deterministic behaviour. TSN uses time synchronization, traffic shaping, strict priority, and resource reservation mechanisms to provide a reliable and deterministic network environment suitable for real-time applications. However, for these mechanisms to work and TSN to achieve high performance, the network must be fully synchronized. In this thesis, we aim to integrate existing legacy devices into a TSN network without incorporating TSN functionality into them, as implementing all TSN standards requires significant investments in time, financial resources, and infrastructure upgrades. However, as the legacy devices don’t have TSN capabilities and cannot implement TSN synchronization protocols, they cannot synchronize with the TSN switches, which causes negative adverse such as clock drift between the TSN switches and the legacy end-stations. In this thesis, we aim to minimize the clock drift in the partially synchronized heterogeneous network, allowing researchers and organizations to take advantage of the benefits of adopting TSN into a legacy network without facing those issues. To solve the clock drift that occurs between the legacy end-stations and the TSN switches, we implemented one solution by combining those proposed solutions in the previous work [9] by using the Drift Detector (DD) and the Centralised Network Configuration element (CNC). This will be resolved by DD measuring and calculating the difference between the expected and actual reception of the messages from the receiver end-station. The CNC later uses the variation values detected by the DD to modify the TSN schedule and updates the network with the new period. In this way, we could minimize the negative consequences caused by partial synchronization in the network.

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