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Multi-UE 5G RAN Measurements: A Gamut of Architectural Options

IEEE ACCESS 2025年 13卷 1846-1866页

作者： Ingo Grohmann, Andreas Seidel, Mauri Itting, Sebastian A. W. Cheng, Ray-Guang Reisslein, Martin Fitzek, Frank H. P. Tech Univ Dresden Deutsch Telekom Chair Commun Networks D-01062 Dresden Germany Ctr Tactile Internet Human In The Loop CeTI D-01187 Dresden Germany Natl Taiwan Univ Sci & Technol Dept Elect & Comp Engn Taipei 106 Taiwan Arizona State Univ Sch Elect Comp & Energy Engn Tempe AZ 85287 USA

The Radio Access Network (RAN) of Fifth Generation (5G) communication systems critically influences the overall performance and cost of a 5G system. 5G RANs allow for a gamut of implementations ranging from closed (carrier-grade) implementations by traditional vendors that are expensive and configured by the vendor to RANs that are compliant with the specifications of the O-RAN ALLIANCE, i.e., to so-called O-RANs. O-RANs are available in closed-source and open-source implementations;O-RANs can be configured by the operator and are cheaper than the closed RANs. Understanding the packet-level performance characteristics of these different 5G RAN implementations is a prerequisite for informed network planning and deployment, particularly for Non-Public Networks (NPNs) for specific use cases. Existing measurement studies have mainly considered a single User Equipment (UE);however, practical networks typically operate with multiple UEs. We conduct packet-level measurements for concurrent over-the-air transmissions to (downstream) and from (upstream) multiple UEs for a wide range of packet transmission rates. We consider current representative implementations of three RAN architectural options: closed RAN (based on Nokia system), closed-source O-RAN (based on Airspan system), and open-source O-RAN (based on srsRAN Project system). We find that the one-way packet delays and the packet loss probabilities can vary sharply among the multiple concurrently operating UEs (which are identical in model and configuration) in the closed RAN and open-source O-RAN;whereas, the packet-level performance tends to be more consistent among the UEs in the closed-source O-RAN. Our measurement results provide a baseline for future research on refining RAN operations for multiple concurrent packet flows.

关键词： 5G mobile communication Open RAN Costs 3GPP Packet loss Standards Interoperability Delays Companies Wireless networks 5G O-RAN Non-Public Network (NPN) open-source packet delay packet loss probability Radio Access Network (RAN) testbed

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Using Fiber Optic Bundles to Miniaturize Vision-Based tactile Sensors

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IEEE TRANSACTIONS ON ROBOTICS 2025年 41卷 62-81页

作者： Di, Julia Dugonjic, Zdravko Fu, Will Wu, Tingfan Mercado, Romeo Sawyer, Kevin Most, Victoria Rose Kammerer, Gregg Speidel, Stefanie Fan, Richard E. Sonn, Geoffrey Cutkosky, Mark R. Lambeta, Mike Calandra, Roberto Stanford Univ Stanford CA 94305 USA Meta Menlo Pk CA 92093 USA Tech Univ Dresden LASR Lab D-01307 Dresden Germany Sch Embedded & Composite AI SECAI D-01069 Dresden Germany Natl Ctr Tumor Dis NCT UCC Dresden D-01307 Dresden Germany Ctr Tactile Internet Human Inthe Loop CeTI D-01069 Dresden Germany

Vision-based tactile sensors have recently become popular due to their combination of low cost, very high spatial resolution, and ease of integration using widely available miniature cameras. The associated field of view and focal length, however, are difficult to package in a human-sized finger. In this article we employ optical fiber bundles to achieve a form factor that, at 15 mm diameter, is smaller than an average human fingertip. The electronics and camera are also located remotely, further reducing package size. The sensor achieves a spatial resolution of 0.22 mm and a minimum force resolution 5 mN for normal and shear contact forces. With these attributes, the DIGIT Pinki sensor is suitable for applications such as robotic and teleoperated digital palpation. We demonstrate its utility for palpation of the prostate gland and show that it can achieve clinically relevant discrimination of prostate stiffness for phantom and ex vivo tissue.

关键词： Robot sensing systems Optical fibers Optical fiber sensors Cameras tactile sensors Robots Elastomers Lighting Optical imaging Spatial resolution Deep learning in robotics fiber optics force and tactile sensing medical robotics object hardness perception for grasping and manipulation robotic palpation tissue palpation

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QGD-OE: IMU Orientation Estimation Based on Gradient Descent in the Quaternion Field

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IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT 2025年 74卷

作者： Radak, Hristina Scheunert, Christian Reisslein, Martin Fitzek, Frank H. P. Tech Univ Dresden Deutsch Telekom Chair Commun Networks D-01062 Dresden Germany Tech Univ Dresden Chair Informat Theory & Machine Learning ITML D-01062 Dresden Germany Arizona State Univ Sch Elect Comp & Energy Engn Tempe AZ 85287 USA Tech Univ Dresden Ctr Tactile Internet Human In The Loop CeTI D-01062 Dresden Germany

Orientation estimation based on inertial measurement units (IMUs) has emerged as a promising solution for real-time orientation tracking. Quaternion numbers are frequently employed by estimation algorithms to represent orientation in 3-D space. In recent years, gradient descent-based algorithms have been extensively utilized for quaternion-based orientation estimation due to their simplicity and effectiveness. However, the real functions of quaternion variables are nonanalytic. Current state-of-the-art algorithms for orientation estimation based on gradient descent methods overcome this obstacle by transforming the problem from the quaternion domain into the real domain. In contrast, we leverage the mathematical definition of the quaternion gradient based on the generalized Hamilton-real (GHR) algebra to solve the orientation estimation optimization problem based on IMUs directly in the quaternion domain. More specifically, we derive the accelerometer and magnetometer gradient descents in the quaternion domain and propose the quaternion gradient descent orientation estimation (QGD-OE) algorithm to estimate orientation from these gradient descents. We compare our QGD-OE algorithm with two state-of-the-art orientation estimation algorithms. We find that the QGD-OE algorithm achieves higher accuracy, improved robustness, and shorter convergence time than state-of-the-art methods. The comparison highlights the deficiencies of transforming from the quaternion domain into the real domain and underscores the importance of conducting gradient descent and estimation optimization in the quaternion domain.

关键词： Quaternions Estimation Magnetic field measurement Sensors Magnetometers Magnetic domains Vectors Accelerometers Sensor fusion Gyroscopes Gradient descent inertial measurement unit (IMU) orientation estimation quaternions sensor fusion

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Enhancing the Force Transparency of the Energy-Reflection-Based Time-Domain Passivity Approach

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IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY 2025年第1期33卷 181-188页

作者： Panzirsch, Michael Singh, Harsimran Xu, Xiao Dietrich, Alexander Hulin, Thomas Steinbach, Eckehard Albu-Schaeffer, Alin German Aerosp Ctr DLR Inst Robot & Mechatron D-82234 Wessling Germany Tech Univ Dresden Ctr Tactile Internet Human Loop CeTI Cluster Excellence D-01307 Dresden Germany Tech Univ Munich Munich Inst Robot & Machine Intelligence Chair Media Technol Sch Computat Informat & Technol D-80333 Munich Germany Tech Univ Munich TUM Sch Computat Informat & Technol D-85748 Garching Germany

The time-domain passivity approach (TDPA) was developed and applied to tackle a variety of control challenges such as noncollocated force sensing, authority scaling, or delayed coupling in robotic applications. Specifically for delay, recently, the energy-reflection-based TDPA (TDPA-ER) was proposed to improve position tracking and force-feedback quality. In contrast to the conventional TDPA, the TDPA-ER intrinsically prevents position drift, thus substantially increasing the coupling rigidity. Here, we extend the TDPA-ER to further enhance the force transparency perceived by the operator in teleoperation scenarios. The extension is based on two independent control strategies that, among others, reorganize the energy distribution of TDPA-ER and ensure more continuous force profiles through the deflection-domain passivity approach (DDPA). Experiments confirm the improvement of force-feedback quality and force continuity with regard to TDPA-ER. Furthermore, it is shown that interactions with dynamic objects and active environments can be handled robustly with the proposed teleoperation control strategies.

关键词： Force Robots Delays Couplings Input devices Attenuation Damping Time-domain analysis tactile internet Impedance Deflection-domain control teleoperation telerobotics

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COSMIC - Coding for Optimized Sending in Multimedia InterPlanetary Communication

COSMIC - Coding for Optimized Sending in Multimedia InterPla...

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International Conference on Information Networking

作者： Sandra Zimmermann Paul Schwenteck Christian Vielhaus Juan A. Cabrera Frank H. P. Fitzek Deutsche Telekom Chair of Communication Networks TU Dresden Germany Centre for Tactile Internet with Human-in-the-Loop (CeTI)

ISBN: (数字)9798331506940

ISBN: (纸本)9798331506957

A popular technique for enhancing Content Delivery Networks (CDNs) is leveraging the opportunities provided by Peer to Peer (P2P) networks, of which the Interplanetary File System (IPFS) is a widely used one. While IPFS tends to perform well only in homogeneous networks, performance tends to quickly deteriorate when the channel parameters of individual peers differ, which is the case in real-world scenarios. A crucial technology for facilitating the flexible distribution of data requests is Random Linear Network Coding (RLNC). The RLNC technology is leveraged by the protocol Storing coded Packets In-advance For IPFS (SPIFI). Based on SPIFI, we design and implement the Coding for Optimized Sending in Multimedia InterPlanetary Communication (COSMIC) protocol, which uses an adaptive data request scheme to fit all imaginable network configurations. We compare the performance of the three protocols, IPFS, SPIFI, and COSMIC, in tailored and random test cases. To quantify performance, we use the transmission time and transmitted overhead as our metrics. Regarding the transmission time, COSMIC beats the other protocols by at least $\mathbf{3 0 \%}$. The transmitted overhead of COSMIC is slightly worse than SPIFI, but still beats IPFS by a wide margin. For comparison, we also calculate the minimal theoretically possible transmission time in a distribution network with random parameters as a lower bound.

关键词： Measurement Knowledge engineering Lower bound Adaptive systems Distributed databases Distribution networks Network coding Encoding InterPlanetary File System Multimedia communication

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Melt spinning of sustainable high-quality polypropylene from post-consumer waste for monofilaments

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TEXTILE RESEARCH JOURNAL 2025年

作者： Lukoschek, Stephanie Frankenbach, Leopold Alexander Cherif, Chokri Tech Univ Dresden Inst Text Machinery & High Performance Mat Technol Dresden Germany TUD Dresden Univ Technol Ctr Tactile Internet Human Inthe Loop CeTI Dresden Germany

The growing emphasis on sustainability in the textile industry demands innovative solutions for material sourcing and production processes. This study investigates the melt spinning of high-quality polypropylene monofilaments derived from post-consumer waste, focusing on the recycling of food packaging from the plastic waste collection system in Germany. The research explores potential pathways to produce monofilaments that maintain the mechanical properties required for textile applications. Five commercially available polypropylene materials were examined, including a homopolymer polypropylene (hPP) and four recycled polypropylene variants obtained from post-consumer waste. Prior to processing, the materials underwent comprehensive thermoanalytical, rheological, and visual assessments to characterize their thermal stability, flow behavior, and appearance, respectively. The melt-spinning process was carried out by producing monofilaments and evaluating the basic mechanical properties and processability of each material under various process parameters. The mechanical and physical properties of the monofilaments-including tensile strength and elongation-were thoroughly analyzed. Key findings demonstrate that recycled polypropylene can yield monofilaments with mechanical properties comparable to those of virgin materials, highlighting its potential for advanced applications in the textile industry. The study provides valuable insights into the performance and limitations of post-consumer polypropylene in modern melt-spinning processes, contributing to efforts toward more sustainable material use in textile manufacturing.

关键词： Melt spinning recycling sustainable polypropylene yarns post-consumer

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"Who do you trust?" - levels of evidence in the era of artificial intelligence

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LANGENBECKS ARCHIVES OF SURGERY 2025年第1期410卷 1-2页

作者： Probst, Pascal Wagner, Martin Cantonal Hosp Thurgau Dept Surg Frauenfeld Switzerland Univ Hosp Dept Visceral Thorac & Vasc Surg Dresden Germany TUD Dresden Univ Technol Fac Med Carl Gustav Carus Dresden Germany NCT UCC Dresden Fac Med Natl Ctr Tumor Dis NCT Dresden Germany TUD Dresden Univ Technol Ctr Tactile Internet Human Inthe Loop CeTI Dresden Germany

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Generation of Liquid Crystal Elastomer Fibers via a Wet Spinning Technology with Two-Stage Crosslinking

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POLYMERS 2025年第4期17卷 494页

作者： Benecke, Lukas Schwingshackl, Sina Anna Schyra, Peter Cherif, Chokri Aibibu, Dilbar Tech Univ Dresden Inst Text Machinery & High Performance Mat Technol D-01069 Dresden Germany Tech Univ Dresden Ctr Tactile Internet Human Inthe Loop CeTI D-01062 Dresden Germany

Liquid crystal elastomers (LCE) are a promising material to achieve reversible actuation while being able to perform work, showing great potential as artificial muscles in soft robotics and medical technology. Here, a wet spinning process to prepare liquid crystal elastomer fibers (LCEF) with reversible actuation capability is presented. Furthermore, we demonstrate the ability to process side-chain liquid crystal (LC) 4-Methoxyphenyl 4-(3-butenyloxy)benzoate (MBB) into a fiber, enlarging the material variance available in this field. The wet spinning process is presented and discussed in terms of spinning parameters and their influence on fiber properties, especially LC orientation. Moderate draw ratios of up to 2.3 enable highly oriented mesogens (f = 0.64), enabling the contractile behavior. The generated MBB-based LCEF show low activation temperature (54.52 degrees C), temperature-dependent mechanical properties, reversible contraction behavior while lifting up to 140 times their own weight and are able to perform work of up to 3.857 J kg-1. Actuation properties are compared with human skeletal muscle, and possible strategies of further enhancing the LCEF performance are discussed. The generated data show promising features of the LCEF for use as artificial muscle fibers in medical applications, e.g., prosthetics and artificial cardiac tissue.

关键词： liquid crystal elastomer fiber actuator wet spinning

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NLU: An Adaptive, Small-Footprint, Low-Power Neural Learning Unit for Edge and IoT Applications

IEEE OPEN JOURNAL OF CIRCUITS AND SYSTEMS

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IEEE OPEN JOURNAL OF CIRCUITS AND SYSTEMS 2025年 6卷 85-99页

作者： Rostami, Amirhossein Zeinolabedin, Seyed Mohammad Ali Guo, Liyuan Kelber, Florian Bauer, Heiner Dixius, Andreas Scholze, Stefan Berthel, Marc Walter, Dennis Uhlig, Johannes Vogginger, Bernhard Mayr, Christian Tech Univ Dresden Fac Elect & Comp Engn Dresden Germany Ctr Scalable Data Analyt & Artificial Intelligence D-01062 Dresden Leipzig Germany Blackrock Neurotech Salt Lake City UT USA Tech Univ Dresden Ctr Tactile Internet Human Inthe Loop D-01069 Dresden Germany

Over the last few years, online training of deep neural networks (DNNs) on edge and mobile devices has attracted increasing interest in practical use cases due to their adaptability to new environments, personalization, and privacy preservation. Despite these advantages, online learning on resource-restricted devices is challenging. This work demonstrates a 16-bit floating-point, flexible, power- and memory-efficient neural learning unit (NLU) that can be integrated into processors to accelerate the learning process. To achieve this, we implemented three key strategies: a dynamic control unit, a tile allocation engine, and a neural compute pipeline, which together enhance data reuse and improve the flexibility of the NLU. The NLU was integrated into a system-on-chip (SoC) featuring a 32-bit RISC-V core and memory subsystems, fabricated using GlobalFoundries 22nm FDSOI technology. The design occupies just 0.015mm(2) of silicon area and consumes only 0.379 mW of power. The results show that the NLU can accelerate the training process by up to 24.38x and reduce energy consumption by up to 37.37x compared to a RISC-V implementation with a floating-point unit (FPU). Additionally, compared to the state-of-the-art RISC-V with vector coprocessor, the NLU achieves 4.2x higher energy efficiency (measured in GFLOPS/W). These results demonstrate the feasibility of our design for edge and IoT devices, positioning it favorably among state-of-the-art on-chip learning solutions. Furthermore, we performed mixed-precision on-chip training from scratch for keyword spotting tasks using the Google Speech Commands (GSC) dataset. Training on just 40% of the dataset, the NLU achieved a training accuracy of 89.34% with stochastic rounding.

关键词： Training Systolic arrays System-on-chip Artificial neural networks Vectors Data models Computational modeling Artificial intelligence Hardware acceleration Cloud computing Online learning on-device learning on-chip training deep neural network (DNN) application specific integrated circuit (ASIC) co-design energy efficient hardware accelerator reduced precision computation bfloat16

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3.6 GHz Reflection-type 360°-Phase-Tunable 3-Path Power-Divider With low Phase-Error up to 21.4 dBm Output Power per Path

3.6 GHz Reflection-type 360°-Phase-Tunable 3-Path Power-Div...

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German Microwave Conference

作者： Georg Simon Tanner Maximilian Gottfried Becker Marco Gunia Frank Ellinger Chair for Circuit Design and Network Theory Technische Universitat Dresden Germany Centre for Tactile Internet With Human-in-the-Loop (CeTI) Technische Universitat Dresden Germany

ISBN: (数字)9783982039749

ISBN: (纸本)9798331521790

This article presents the analysis and design of a three-way 360° phase-tunable power divider for a frequency range from 3.4 to 3.8 GHz. In contrast to most publications on phase shifters, this paper studies high power aspects of reflective loads for application in reflect type phase shifter (RTPS) based topologies. Furthermore, the detrimental effect of asymmetric loads on the overall phase shifter performance is discussed. This results in the complete design of the phase-tunable divider incorporating switched line phase shifters and the RTPS allowing output powers up to 21.4 dBm while still providing the whole tuning range with little phase error over the full frequency band. Up to 19.2 dBm output power per path, the phase error is below 5°.

关键词： Power dividers Microwave measurement Power measurement Phase measurement Phase shifters Switches Frequency conversion Topology Power generation Tuning

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