Swen Leugner, M.Sc.
|Address||TH Lübeck - University of Applied Sciences, Electrical Engineering and Computer Sciences
Mönkhofer Weg 239
D-23562 Lübeck, Germany
|Phone||+49 (0)451 300-5692|
Since 1 May 2016, I am a research associate and Ph.D. student at the Center of Excellence Communication - Systems - Applications at the University of Applied Science Lübeck. Within the scope of my master thesis, I am engaged in indoor localization and the development of a Time Difference of Arrival locating system. My further interests lie in the field of distributed systems, hardware development, sensor systems, and system development. My research focus lies in the optimization of distributed systems and their integration.
- Born on December 1st 1985
- Study of Electrical Engineering Energy Systems and Automation Engineering at the University of Applied Science Lübeck until 2014
- Study of Electrical Engineering Applied Information Technology at the University of Applied Science Lübeck until 2016
- Since May 1st 2016 research associate at the Communications - Systems - Applications Center of Excellence
|||Drahtlose Robuste Adaptive Industrielle Systeme , In ITG-Fachbericht-Mobilkommunikation VDE VERLAG GmbH, 2018. [bib] [abstract]|
Die industrielle Fertigung wandelt sich mit der Digitalisierung. Fertigungsstücke werden individuell durch Industrie 4.0-Technologien; sie sind jederzeit und überall erfassbar. Fertigungsprozesse werden digitalisiert und bilden Struktur und Verhalten einer Fertigungs- und Produktionsstrasse ab, womit sich wichtige Erkenntnisse zum Ablauf gewinnen lassen. Dies setzt eine Vernetzung der Fertigungsstücke voraus, welche die klassische Automatisierung ergänzt. Drahtlose Sensoren sind an Fertigungsstücke gekoppelt und bilden großflächige und dichte Sensornetze. Messgrößen der Sensoren sind beispielsweise Ort, Zeit, Temperatur, Beschleunigung, Geräusch oder Luftfeuchte, welche nach Anforderung der Datenanalyse ausgewählt und ausgewertet werden. Derartige Sensornetze stellen neue Herausforderungen und Forschungsfragen an Industrie 4.0-Anwendungen. Das Projekt DRAISE hat das Ziel, produktionsrelevante Daten in Industrieanlagen zuverlässig zu erfassen und entsprechend aufzubereiten. Hierfür werden Transportwagen einer Fertigung drahtlos vernetzt und Temperatur, Erschütterung, Position und Zeit erfasst. Zusätzlich interagieren die Mitarbeiter in der Produktion über eine definierte Mensch-Maschine-Schnittstelle mit dem System. Zur Minimierung der Auswirkungen durch andere, drahtlose Systeme werden Time Division Multiple Access (TDMA)-basierende Protokolle für die Single-Hop- und Multi-Hop-Kommunikation entwickelt. Die Kommunikation wird durch Lokalisierungskomponenten ergänzt, welche mit einem System auf Basis von Ultra-Wide-Band (UWB) implementiert ist. Für die angestrebte, zuverlässige und robuste Kommunikation werden zukünftig Frequenzsprungverfahren und Spectrum Sensing die entwickelten Protokolle erweitern. Ein großflächig und produktiv eingesetzter Demonstrator dient der ständigen Leistungsbewertung des Systems.
|||UWB-based Single Reference Point Positioning System , In ITG-Fachbericht-Mobilkommunikation VDE VERLAG GmbH, 2017. [bib] [abstract]|
Indoor positioning enables new applications, for instance monitoring of goods in smart factories. For such applications, indoor positioning requires cost-effective solutions with high accuracy. State-of-the-art positioning systems are expensive due to high infrastructure and maintenance costs. In this paper we suggest an accurate UWB-based single reference point positioning system using multiple antennas. We compare lateration and hyperbolic lateration as positioning methods and present efficient algorithms for UWB-based single reference point positioning systems. We present theoretical limits based on the Cramer-Rao lower bound and derive an error estimation as well as evaluation results. Our measurements indicate that decimeter accuracy is possible.
|||eNAV - Enhanced Co-Existence of IEEE802.15.4 and IEEE 802.11 , In IEEE Symposium on Local and Metropolitan Area Networks, 2019. [bib] [abstract]|
In the future, the Internet of Things will become increasingly important in a Smart City, for example. Today, however, established radio standards in license-free bands show that radios in heterogeneous networks interfere with each other. This includes radio standards in particular in the license-free 2.4 GHz ISM band. In this publication, we investigate IEEE 802.15.4 and IEEE 802.11 and show how radios in heterogeneous networks coordinate their actions in order to share radio resources. With the Extended Network Allocation mechanism, we demonstrate that IEEE 802.15.4 frame losses are reduced by a maximum of 50 percent even if strong interference occurs. We also show the design and implementation of an Extended Network Allocation enabled Gateway for the Internet of Things and provide a detailed description. For evaluation, we conduct measurements in a realworld application and environment.
|||Minimizing Indoor Localization Errors for Non-Line-of-Sight Propagation , In International Conference on Localization and GNSS, 2018. [bib] [abstract]|
Indoor Localization becomes more important, as it provides additional context for many applications for example in the Internet of Things (IoT). Time-of-flight measurements, as a basis for distance estimation, are susceptible for non-line-of-sight (NLOS) propagation, resulting in large distance errors. Standard least squares solutions to estimate the targets location do not account for NLOS propagation which results in large scale errors. We investigate the difference between L1- and L2-minimization and present a new framework based on a modified RANSAC approach. Additionally, we investigate a Support Vector Machine (SVM) to detect NLOS measurements.We present simulation and measurement results and evaluate our approach. We show that our framework delivers better performance in presence of NLOS propagation compared to plain L1- or L2-minimization.
|||Listen and Talk in IEEE 802.15.4 with Dual Radio , In 2018 Advances in Wireless and Optical Communications (RTUWO) (RTUWO'18), 2018. [bib] [abstract]|
In wireless sensor networks, the license-free 2.4 GHz industrial medical and scientific band is increasingly popular. The popularity of this license-free band results in growing heterogeneous wireless networks in which the channel state detection becomes difficult. In this paper, we present a novel solution to enable Listen and Talk with an IEEE 802.15.4 dual radio transceiver sensor node, to provide a channel state detection. In contrast, to Listen before Talk or Clear Channel Assessment, our approach named Advanced Clear Channel Assessment talks and listens, which means checking the channel state during transmission. We show that Advanced Clear Channel Assessment increases the channel busy detection compared to Clear Channel Assessment by a factor of six. Furthermore, we provide a novel metric to compare detection algorithms for channel state based on threshold levels.
|||TriClock – Clock Synchronization compensating Drift, Offset and Propagation Delay , In IEEE International Conference on Communications, 2018. [bib] [abstract]|
In wireless sensor networks (WSN) precise clock synchronization is still a challenge e.g. for synchronized medium access control (MAC). State of the art solutions require many messages or neglect clock drifts or propagation delay. In multi-hop networks synchronization errors increase with the number of hops because numerous messages increase latency. The latency and clock drift reduces synchronization accuracy. Finally, propagation delay introduces additional synchronization offsets. We introduce a novel synchronization protocol that requires a single message to compensate both clock offset and clock drift and one additional message to account for propagation delay. With this minimal amount of messages, an efficient multi-hop synchronization is practicable. We implement our approach on a DWM1000 hardware and evaluate the protocol in single-hop and multi-hop configuration. In our preliminary experiments, we achieved a synchronization accuracy of 0.46 ns in a single-hop configuration within 3.6 ms and 6 ns in a multi-hop configuration for 5 hops within 11 ms which is appropriate for MAC and time-division multiple access (TDMA) implementations.
|||DRAISE - Drahtlose, Roboste Adaptive, Industrielle Systeme , In Zukunft der Netze 2017, Postersession, 2017. [bib]|
|||Comparison of wired and wireless synchronization with clock drift compensation suited for U-TDoA localization , In 13th Workshop on Positioning, Navigation and Communication, 2016. [bib] [abstract]|
Indoor localization with Uplink Time Difference of Arrival (U-TDoA) provides good scalability, high updates rates and high accuracy. However, clock errors lead to localization errors and synchronization is important. In this paper, we design and implement wired and wireless synchronization and provide a comparison between them. We design and implement a wireless synchronization with clock drift compensation. For wired and wireless synchronization, we discuss reasons for clock deviation that lead to localization errors. We evaluate both approaches in a U-TDoA measurement setup. Finally, we provide recommendations for wired and wireless synchronization.
|||Suitable Path Loss Model for LoRa networks in suburban areas , (T. M. Buzug et. al., ed.), 2019. [bib] [abstract]|
Network planning requires a suffficiently accurate model of the path loss of signals. This paper is analyzing the suitability of the Okumura, ECC-33 and COST231 model for the LoRaWAN technology. Since the frequency band is different than Wifi and LTE, the results will differ. Therefore, a measurement in an area of Luebeck is performed and compared to the predictions of the different models. The most suitable model is then used and extended by a loss per building factor. This factor is determined by a series of measurements performed in front of and behind a building. The COST231 and Okumura models show the best prediction, while the Okumura model underestimates the path loss and the COST231 overestimates it.
|||Lessons learned: Indoor Ultra-Wideband localization systems for an industrial IoT application , Technical report, Technische Universität Braunschweig, 2018. [bib] [pdf] [abstract]|
Since ultra-wideband (UWB) transceivers are available for wireless sensor networks, the usage in research and industry increased. Research efforts resulted in methods, measurement results, and solutions under laboratory conditions for a variety of indoor localization problems provided to the community. In this paper, we present an indoor positioning system (IPS) that is installed in a $mathbf1500 m^2$ real world production facility. In this real-world application, we faced some challenges that research has not addressed yet. For instance, challenges are receiving UWB signals from other floors in a multistory building through windows and multipath effects at walls like reflexions. We present solutions to increase the availability of such large-scale IPS, give a performance evaluation and recommendation for a modified NMEA sentence named iNMEA for IPS receivers.