Dr.-Ing. Robin Klose

Decentralized Ultra-Reliable Low-Latency Communications / Postdoc

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Biography

Robin Klose pursues research in the field of ultra-reliable low-latency wireless communications without the involvement of cellular infrastructure. In emerging cyber-physical systems, like autonomous driving, it becomes more and more important to enable autonomous machines to coordinate and to react fast, anywhere and anytime. Robin Klose works on novel solutions to deliver messages quickly and reliably throughout wireless multi-hop networks.

Offered Theses Topics

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2022 Available now

CSMA/CD for Wi-Fi

Supervisor: Robin Klose

Motivation Carrier Sense Multiple Access with Collision Detection (CSMA/CD) is a technique used in wired networks like Ethernet (IEEE 802.3) to improve network performance by efficient medium access. When a collision is detected, the colliding nodes terminate their transmissions to keep the collision time as short as possible. This effectively improves the utilization of the transmission medium, since less time is spent in collisions and the time between transmission attempts is reduced. In wireless networks, however, CSMA/CD is generally assumed to be impractical due to the physical characteristics of the wireless channel. In fact, the power of a signal degrades by orders of magnitudes on its way from transmitter to receiver due to free space path loss and signal propagation effects, such as attenuation and reflections. Therefore, even if a transmitter was equipped with a separate receive antenna, its own transmission would typically drown out the weak signals from other transmitters, which would render the detection of weak signals impossible. Nevertheless, recent research has demonstrated that self-interference cancellation techniques become feasible, which allows to design full-duplex radios [1]. This might effectively be key to the design of CSMA/CD for IEEE 802.11-based networks, allowing for enhanced network performance under high load conditions [2]. [1] Mayank Jain, Jung Il Choi, Taemin Kim, Dinesh Bharadia, Siddharth Seth, Kannan Srinivasan, Philip Levis, Sachin Katti, and Prasun Sinha. “Practical, Real-Time, Full Duplex Wireless”, 17th annual international conference on Mobile computing and networking (ACM MobiCom '11). Las Vegas, Nevada, USA, 2011, pp. 301-312. [2] Konstantinos Voulgaris, Athanasios Gkelias, Imran Ashraf, Mischa Dohler and A. H. Aghvami. “Throughput Analysis of Wireless CSMA/CD for a Finite User Population”, IEEE Vehicular Technology Conference, Montreal, Quebec, CA, 2006, pp. 1-5. Goal Literature review: Review different self-interference cancellation techniques and assess their suitability for 802.11-based networks. Also review literature relating to channel access techniques. CSMA/CD design: Make a conceptual design of a fully-fledged CSMA/CD mechanism, which also takes practical limitations into account, such as settling times of gain controls. Your design may also employ correlation techniques to detect weak signals from far-away nodes. Implementation: Implement your CSMA/CD design on a software-defined radio. Self-interference cancellation might require a combination of well-considered antenna placement on the device, analog cancellation in the RF band, and digital cancellation in the baseband. Your implementation may be based on GNU Radio and USRP, or on WARP. Evaluation: Evaluate the performance of individual components of your implementation (e.g., the self-interference cancellation gain), as well as the overall performance of CSMA/CD nodes in a real network, as compared to conventional CSMA/CA.

2021 Completed

Protocol Design for Energy-Efficient Broadcast Tree Contruction in Wireless Ad-Hoc Networks

Supervisor: Robin Klose

2020 Completed

Low-Latency Flooding in IEEE 802.11g Networks through Concurrent Broadcasting with Wireless Synchronization using WARP Software-Defined Radios

Supervisor: Robin Klose

2018 Completed

Separation of Channel Coefficients in Concurrent Wi-Fi Transmissions using Deep Neural Networks

Supervisor: Robin Klose

2018

Separation of Channel Coefficients with Deep Neural Networks

Supervisor: Robin Klose

Motivation The separation of channel coefficients is a time-consuming operation. In this thesis project, we are going to explore the suitability of deep neural networks (DNNs) to speed up a specific PHY-related optimization task Goal The goal of this project is to explore the suitability of DNNs to separate channel coefficients. The project main goals are: Research the literature about uses of DNNs in other optimization problems Explore suitable DNN configurations for the envisioned task Evaluate the DNN's performance in terms of accuracy and speed

2018 Completed

NEAT-TCP: Generation of TCP Congestion Control through Neuroevolution of Augmenting Topologies for Wireless Multi-Hop Networks

Supervisor: Robin Klose

Motivation TCP performance in wireless multi-hop networks (WMNs) is hard to achieve due to losses on the wireless channel, interferences and limited resources at individual nodes. Recent research has proposed a simple neural network (NN) structure with one input layer, two hidden layers, and one output layer that efficiently applies congestion control and that results in significant performance improvements compared to conventional TCP variants [1]. Further, NeuroEvolution of Augmenting Topologies (NEAT) is a method based on evolutionary algorithms that can outperform fixed-topology NNs in reinforcement learning tasks. We expect that NEAT may improve the performance of manually crafted NNs like iTCP even further. Goal The goal of this project is to assess the ability of NEAT to further improve the performance of an iTCP-based congestion control algorithm in the context of WMNs. The project main goals are: Implement iTCP in a network simulation environment (ns-3) Use NEAT to generate a modified NN structure for congestion control Compare the performance of the modified congestion control to the initial iTCP-based version [1] A. B. M. Alim Al Islam and Vijay Raghunathan, “iTCP: an intelligent TCP with neural network based end-to-end congestion control for ad-hoc multi-hop wireless mesh networks”, Wireless Networks, Volume 21, Issue 2, pp. 581–610, February 2015. doi: 10.1007/s11276-014-0799-6 [2] Kenneth O. Stanley and Risto Miikkulainen, “Evolving Neural Networks through Augmenting Topologies”, Evolutionary Computation 10:2, pp. 99-127, MIT Press, 2002. doi: 10.1162/106365602320169811

2018 Completed

Practical Broadcast Tree Construction with Potential Game for Energy-Efficient Data Dissemination in Ad-Hoc Networks

Supervisor: Robin Klose

Motivation This project addresses the problem of energy-efficient data dissemination from a source node to all other nodes in a wireless multi-hop network. Mahdi Mousavi et al. from the Communications Engineering Lab at TU Darmstadt have devised a decentralized algorithm towards this goal that is based on game theory [1]. While simulation results have shown that this mechanism significantly outperforms other conventional flooding mechanisms, its practical applicability still remains unexplored. Goal The goal of this thesis project is to design a practical protocol that runs the game theoretical algorithm in [1] and to evaluate its performance in a network simulation environment. The project main goals are: Analyze the game theoretical algorithm [1] for limiting assumptions Devise a practical protocol for broadcast tree construction that is based on [1] Implement this protocol in a simulation environment (ns-3) Evaluate the energy efficiency of the constructed broadcast tree in comparison to conventional flooding techniques while taking the protocol overhead into account [1] Mahdi Mousavi, Hussein Al-Shatri, Matthias Wichtlhuber, David Hausheer and Anja Klein, “Energy-Efficient Data Dissemination in Ad Hoc Networks: Mechanism Design with Potential Game”, 2015 International Symposium on Wireless Communication Systems (ISWCS), Brussels, 2015, pp. 616-620. doi: 10.1109/ISWCS.2015.7454421

2017 Completed

Estimating Global MANET Metrics Based on Locally Observed Information

Supervisor: Robin Klose

Motivation Knowledge of global network state is crucial for several innovative network optimization techniques. Essentially, incorporating knowledge about the overall network state into locally made decisions at decentralized nodes might improve the overall network performance. A node might for instance perform transitions between network mechanisms that are optimized for certain network conditions. However, an individual node's scope of the network is limited in practice since it is able to overhear the wireless channel only locally, and explicit notification about global network state would result in large overhead. Therefore, we seek to extend a node's view into the network by means of machine learning techniques. Goal The goal of this thesis is to estimate global metrics of a mobile ad-hoc network (MANET) by means of locally overheard information in a network simulation environment. Literature review: Identify network optimization techniques that rely on global network knowledge and extract their requirements. Define metrics: Make a list of global network properties that should be classified or estimated. Identification of features: Identify potential features that can be obtained by traffic monitoring. Features that comprise relevant information about distant nodes might for instance be obtained by inspecting packet headers of the higher layers (e.g., network layer and transport layer). Feature engineering and machine learning: Select and engineer features that can be obtained by overhearing the wireless channel. Implementation: Run experiments with the ns-3 network simulator and evaluate the estimator's performance.

2017 Completed

Collide, Collate, Collect: Recognizing Senders in Wireless Collisions

Supervisor: Robin Klose

Description With wireless mobile IEEE 802.11a/g networks, collisions are currently inevitable despite effective counter measures. This work proposes an approach to detect the MAC addresses of transmitting stations in case of a collision, and measures its practical feasibility. Recognizing senders using cross-correlation in the time domain worked surprisingly well in simulations using Additive White Gaussian Noise (AWGN) and standard Matlab channel models. Real-world experiments using software-defined radios also showed promising results in spite of decreased accuracy due to channel effects. During the experiments, various Modulation and Coding Schemes (MCSs) and scrambler initialization values were compared. Knowledge about which senders were transmitting leading up to a collision could help develop new improvements to the 802.11 MAC coordination function, or serve as a feature for learning-based algorithms. Motivation Collisions on wireless networks most likely lead to packet losses. Current network protocols typically recover from these situations by retransmissions. In doing so, the overall network capacity is reduced and the network delay increases with the amount and duration of collisions. However, collided frames may still reveal valuable information that might be suitable for advanced protocol designs. Goal Detect frame alignments of collided frames at the PHY. Devise techniques to detect known data, such as MAC header fields. Analyze real network scenarios with respect to collisions, classify observed events (e.g., pairs of hidden terminals) and generate statistics.

2016 Completed

Location Privacy of Digital Trunked Radio

Supervisor: Jiska Classen Robin Klose

Publications

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2023 Technische Universität Darmstadt Darmstadt PhD thesis

Decentralized Ultra-Reliable Low-Latency Communications through Concurrent Cooperative Transmission

Robin Klose

PDF BibTeX DOI: 10.26083/tuprints-00024070

Abstract

Emerging cyber-physical systems demand for communication technologies that enable seamless interactions between humans and physical objects in a shared environment. This thesis proposes decentralized URLLC (dURLLC) as a new communication paradigm that allows the nodes in a wireless multi-hop network (WMN) to disseminate data quickly, reliably and without using a centralized infrastructure. To enable the dURLLC paradigm, this thesis explores the practical feasibility of concurrent cooperative transmission (CCT) with orthogonal frequency-division multiplexing (OFDM). CCT allows for an efficient utilization of the medium by leveraging interference instead of trying to avoid collisions. CCT-based network flooding disseminates data in a WMN through a reception-triggered low-level medium access control (MAC). OFDM provides high data rates by using a large bandwidth, resulting in a short transmission duration for a given amount of data. This thesis explores CCT-based network flooding with the OFDM-based IEEE 802.11 Non-HT and HT physical layers (PHYs) to enable interactions with commercial devices. An analysis of CCT with the IEEE 802.11 Non-HT PHY investigates the combined effects of the phase offset (PO), the carrier frequency offset (CFO) and the time offset (TO) between concurrent transmitters, as well as the elapsed time. The analytical results of the decodability of a CCT are validated in simulations and in testbed experiments with Wireless Open Access Research Platform (WARP) v3 software-defined radios (SDRs). CCT with coherent interference (CI) is the primary approach of this thesis. Two prototypes for CCT with CI are presented that feature mechanisms for precise synchronization in time and frequency. One prototype is based on the WARP v3 and its IEEE 802.11 reference design, whereas the other prototype is created through firmware modifications of the Asus RT-AC86U wireless router. Both prototypes are employed in testbed experiments in which two groups of nodes generate successive CCTs in a ping-pong fashion to emulate flooding processes with a very large number of hops. The nodes stay synchronized in experiments with 10 000 successive CCTs for various modulation and coding scheme (MCS) indices and MAC service data unit (MSDU) sizes. The URLLC requirement of delivering a 32-byte MSDU with a reliability of 99.999 % and with a latency of 1 ms is assessed in experiments with 1 000 000 CCTs, while the reliability is approximated by means of the frame reception rate (FRR). An FRR of at least 99.999 % is achieved at PHY data rates of up to 48 Mbit/s under line-of-sight (LOS) conditions and at PHY data rates of up to 12 Mbit/s under non-line-of-sight (NLOS) conditions on a 20 MHz wide channel, while the latency per hop is 48.2 µs and 80.2 µs, respectively. With four multiple input multiple output (MIMO) spatial streams on a 40 MHz wide channel, a LOS receiver achieves an FRR of 99.5 % at a PHY data rate of 324 Mbit/s. For CCT with incoherent interference, this thesis proposes equalization with time-variant zero-forcing (TVZF) and presents a TVZF receiver for the IEEE 802.11 Non-HT PHY, achieving an FRR of up to 92 % for CCTs from three unsyntonized commercial devices. As CCT-based network flooding allows for an implicit time synchronization of all nodes, a reception-triggered low-level MAC and a reservation-based high-level MAC may in combination support various applications and scenarios under the dURLLC paradigm.

2023 Sensors Article

Energy-Efficient Decentralized Broadcasting in Wireless Multi-Hop Networks

Artur Sterz Robin Klose Markus Sommer Jonas Höchst Jakob Link Bernd Simon Anja Klein Matthias Hollick Bernd Freisleben

PDF BibTeX DOI: 10.26083/tuprints-00024503

Abstract

Several areas of wireless networking, such as wireless sensor networks or the Internet of Things, require application data to be distributed to multiple receivers in an area beyond the transmission range of a single node. This can be achieved by using the wireless medium’s broadcast property when retransmitting data. Due to the energy constraints of typical wireless devices, a broadcasting scheme that consumes as little energy as possible is highly desirable. In this article, we present a novel multi-hop data dissemination protocol called BTP. It uses a game-theoretical model to construct a spanning tree in a decentralized manner to minimize the total energy consumption of a network by minimizing the transmission power of each node. Although BTP is based on a game-theoretical model, it neither requires information exchange between distant nodes nor time synchronization during its operation, and it inhibits graph cycles effectively. The protocol is evaluated in Matlab and NS-3 simulations and through real-world implementation on a testbed of 75 Raspberry Pis. The evaluation conducted shows that our proposed protocol can achieve a total energy reduction of up to 90% compared to a simple broadcast protocol in real-world experiments.

2020 IEEE International Conference on Communications (icc2020) Conference

NEAT-TCP: Generation of TCP Congestion Control Through Neuroevolution of Augmenting Topologies

Kay Luis Wallaschek Robin Klose Lars Almon Matthias Hollick

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Abstract

We present NEAT-TCP, a novel technique to automatically generate congestion control algorithms in a data-driven fashion while optimizing towards a specified global system utility. NEAT-TCP employs an artificial neural network (ANN) in each node and generates a population of ANNs by means of an evolutionary algorithm called NEAT. The ANNs run independently from each other at the communication endpoints and take only features as inputs that are locally available at these nodes. We define the system utility as a combined maximization of overall throughput and throughput fairness between flows according to Jain's fairness index. The nodes are deployed in a grid topology in ns-3 simulations, which makes it particularly difficult to maximize the utility due to different interference levels for the data flows. In our experiments, NEAT-TCP achieves 69 % more fairness, 66 % less mean end-to-end delay and 71 % less packet loss in relation to TCP New Reno at the cost of 19 % less overall throughput, which meets our multi-criteria objective.

2019 IEEE Global Communications Conference (GLOBECOM) 2019 Conference

Riding the Waves: Decoding Asynchronous Multi-User MISO via Time-Variant Zero-Forcing

Robin Klose Matthias Hollick

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Abstract

uture wireless communication systems are envisioned to meet stringent latency requirements to support control applications and machine interactions. One important step in this direction is to eliminate waiting times in the protocol stack, which can be achieved by letting multiple nodes transmit the same data concurrently just when the data becomes available. This communication paradigm essentially enables wide-range broadcasting and low-latency flooding. However, imperfect transmitter synchronization may arise in such schemes, which causes signal incoherence, which in turn prohibits reception with conventional decoders. In this paper, we introduce time-variant zero-forcing (TVZF), a novel equalization technique that deals with non-stationary interferences. In doing so, TVZF relaxes the requirements for time and frequency synchronization in concurrent multi-user transmissions. We present a receiver design for asynchronous MU-MISO with IEEE 802.11g compliant signals and evaluate it with over-the-air transmissions in a WARP SDR testbed in LOS and NLOS scenarios. The relative timing and frequency offsets between concurrent transmitters are systematically tuned to assess our receiver's performance in comparison to commodity hardware. For timing offsets up to the length of the cyclic prefix and frequency offsets up to 5 kHz, our receiver achieves average frame reception rates of 97 % and 92 % for LOS and NLOS, respectively.

2019 Proceedings of the IEEE Article

Transitions: A Protocol-Independent View of the Future Internet

Bastian Alt Markus Weckesser Christian Becker Matthias Hollick Sounak Kar Robin Klose Roland Kluge Heinz Koeppl Wasiur R. KhudaBukhsh Manisha Luthra Mahdi Mousavi Max Mühlhäuser Martin Pfannemüller Amr Rizk Andy Schürr Ralf Steinmetz Anja Klein

BibTeX DOI: 10.1109/JPROC.2019.2895964

2019 2019 IEEE International Conference on Pervasive Computing and Communications Workshops, PerCom Workshops 2019 Conference

CoalaViz: Supporting Traceability of Adaptation Decisions in Pervasive Communication Systems

Martin Pfannemüller Markus Weckesser Roland Kluge Janick Edinger Manisha Luthra Robin Klose Christian Becker Andy Schürr

BibTeX

2019 2019 IEEE International Conference on Pervasive Computing and Communications Workshops, PerCom Workshops 2019 Conference

Demo: Visualizing Adaptation Decisions in Pervasive Communication Systems

Martin Pfannemüller Janick Edinger Markus Weckesser Roland Kluge Manisha Luthra Robin Klose Christian Becker Andy Schürr

BibTeX

2018 2018 IEEE International Conference on Communications Workshops (ICC Workshops) Conference

Making Wi-Fi Fit for the Tactile Internet: Low-Latency Wi-Fi Flooding Using Concurrent Transmissions

Francesco Gringoli Robin Klose Matthias Hollick Nahla Ali

BibTeX DOI: 10.1109/ICCW.2018.8403487

Abstract

Real-time human-to-machine and machine-to-machine interactions at the edge of the Internet are the key drivers for research in high-speed and low-latency wireless communication. In order to meet the most stringent latency demands, such interactions should be carried out autonomously by groups of nodes at the edge, potentially resorting to specialized physical layer techniques. While past research has mostly focused on 5G cellular network technology, we assess the feasibility to utilize IEEE 802.11 (Wi-Fi) technology for this purpose. In contrast to existing work on macrodiversity schemes to enhance network capacities, we highlight the potential of macrodiversity to reduce the latency in one-to-many communication scenarios through concurrent network flooding. To this end, we study the practical feasibility of concurrent transmissions with IEEE 802.11, while taking the characteristics of both the DSSS PHY and the OFDM PHY of IEEE 802.11 into account. In particular, we quantify the impact of the limiting factors that impair the decodability of concurrent Wi-Fi transmissions and analyze their combined effects in simulations and practical SDR testbed experiments. In doing so, we also assess the capability of commodity hardware to decode concurrent Wi-Fi transmissions while deliberately introducing signal impairments by tuning the limiting factors. With this, we identify the key parameter limits to enable low-latency flooding at the edge with IEEE 802.11.

2016 6th Workshop on Security and Privacy in Smartphones and Mobile Devices Conference

Analyzing TETRA Location Privacy and Network Availability

Martin Pfeiffer Jan-Pascal Kwiotek Jiska Classen Robin Klose Matthias Hollick

PDF BibTeX DOI: 10.1145/2994459.2994463

Abstract

TETRA is a digital communication standard taking over from analog communication in various emergency services and governmental agencies in Europe since the late 1990s. TETRA has to meet stringent requirements for a dependable communication infrastructure as it is used in the public safety sector by professional users and first responders. In fact, TETRA is claimed to enhance resilience, security, and availability compared to former analog communication standards. In this paper, we demonstrate that TETRA's location privacy and dependability can easily be undermined and weakened. In particular, TETRA devices can be localized by means of antenna arrays and direction finding techniques on the physical layer. Further, we practically evaluate the impact of various jamming and fuzzing attacks on two commonly used devices. The digital standard even raises new attack vectors, since regular beaconing enables localization of idle devices, and forged frames can provably crash devices.

2013 14th IEEE International Symposium on a World of Wireless, Mobile and Multimedia Networks (WoWMoM 2013) Conference

Practical OFDMA in Wireless Networks with Multiple Transmitter-Receiver Pairs

Adrian Loch Robin Klose Matthias Hollick Alexander Kuehne Anja Klein

BibTeX DOI: 10.1109/WoWMoM.2013.6583368

2013 Proceedings of the 2nd Workshop of Software Radio Implementation Forum (SRIF 2013), co-located with ACM Sigcomm 2013 Conference

Evaluating Dynamic OFDMA Subchannel Allocation for Wireless Mesh Networks on SDRs

Robin Klose Adrian Loch Matthias Hollick

BibTeX

2013 Proceedings of the 2013 IEEE International Conference on Sensing, Communication, and Networking (SECON 2013) Conference

A Rapid Prototyping Framework for Practical OFDMA Systems using Software Defined Radios

Robin Klose Adrian Loch Matthias Hollick

BibTeX