Publikationen des Fachgebiets Zuverlässige Maschine-zu-Maschine-Kommunikation der TU IlmenauPublikationen des Fachgebiets Zuverlässige Maschine-zu-Maschine-Kommunikation der TU Ilmenau
Results: 9
Created on: Thu, 28 Mar 2024 23:07:07 +0100 in 0.0722 sec


Haider Shah, Syed Najaf; Martín-Sacristán, David; Ravelo, Carlos; Smeenk, Carsten; Schneider, Christian; Robert, Jörg
Radar-enabled resource allocation in 5G-V2X sidelink communication. - In: IEEE Xplore digital library, ISSN 2473-2001, (2023), S. 1416-1421

Integrated Sensing and Communication (ISAC) has emerged as a key technology in future cellular networks as it allows the integration of radar sensing capabilities into mobile networks by sharing the same spectral and hardware resources. This paper discusses the integration of radar sensing capabilities into 5G Vehicle-to-Everything (V2X) sidelink communication to enable an ISAC-capable 5G- V2X system that requires high-precision radar sensing and highly reliable communication among vehicles and road infrastructure. To meet these requirements in a high-density environment where target objects are moving in close proximity to one another, a radio resource allocation algorithm, based on the sensing-based semi-persistent scheduling (SB-SPS) scheme, has been proposed that allocates additional available time and frequency (bandwidth) resources to the transmitting vehicle for high-resolution radar sensing. Further, to reduce the channel occupancy generated by the transmitting vehicle by occupying the additional resources to perform radar sensing tasks, the approach reserves only the communication resources for future transmissions. The proposed approach is evaluated through a set of performance metrics of both radar sensing and communication including the probability of detection, root mean squared error (RMSE) of range and velocity estimation of target objects under line-of-sight (LOS) conditions, and packet reception ratio. The simulation results demonstrate that the proposed approach allows each vehicle to perform radar sensing while maintaining good communication performance.



https://doi.org/10.1109/ITSC57777.2023.10422629
Chaudhury, Nandan Dutta; Berkelmann, Lukas; Jannsen, Bert; Robert, Jörg
Weighted partial radiation efficiency and effective coverage as key performance indicators for the analysis of automotive antennas. - In: 2023 IEEE Conference on Antenna Measurements and Applications (CAMA), (2023), S. 677-680
ISBN 979-8-3503-2304-7

It is essential to characterize the automotive antenna in its installed state because the metallic car body has a significant influence on the antenna's performance. In this connection, the 5GAA has recommended certain key performance indicators (KPIs), such as the Total Radiated Power (TRP), Partial Radiated Power (PRP), etc. for evaluating automotive antennas. However, these KPIs do not adequately reflect the vehicular integration effects on the antenna’s performance. In order to fill this gap, two novel KPIs have been proposed in this paper, namely, the weighted Partial Radiation Efficiency and Effective Coverage. The weighting scheme for the calculation of the KPIs has been defined based on direction of importance. To demonstrate their significance, two different vehicular antenna integration topologies have been evaluated employing the KPIs. The results have been compared with existing metrics namely PRP and TRP.



https://doi.org/10.1109/CAMA57522.2023.10352819
Klob, Sebastian; Maul, Thomas; Robert, Jörg
Low-cost and ultra-precise synchronization concept for TDoA localization of dairy cows. - In: IEEE Xplore digital library, ISSN 2473-2001, (2023), insges. 6 S.

Implementing modern technologies such as localization in an agricultural environment has received significant interest in recent years. These kinds of systems help farmers to manage their farms more economically. Especially dairy cows often move between the stable and pasture area, so frequent localization is needed in both environments. One faces many challenges when implementing such a system, such as energy supply, limited computing power, and bad radio links. This paper presents a system able to synchronize three receive stations for localizing dairy cows on a field with the help of Time-Difference-Of-Arrival. The focus will be on realizing a cost-effective, energy- and computing-efficient concept that minimizes transferred data and that can be deployed in agricultural environments as well as in other possible indoor and outdoor localization scenarios. To implement such a system, a switching receiver is used that alternates between the reception of a Low Power Wide Area Network signal for localization and a Signal of Opportunity for synchronization. No special hardware is required because the synchronization is realized as a Software Defined Radio system. The impairments caused by this kind of receiver, with a particular focus on synchronization, are analyzed and visualized. Also, the effects of phase noise on the frequency estimation are investigated. It is shown that the theoretical bounds for frequency estimation do not limit the switching receivers’ performance. Initial measurements for the proposed architecture are shown.



https://doi.org/10.1109/IPIN57070.2023.10332226
Maul, Thomas; Robert, Jörg; Klob, Sebastian
Ultra-precise synchronization for TDoA-based localization using signals of opportunity. - In: IEEE Xplore digital library, ISSN 2473-2001, (2023), insges. 6 S.

Precise localization is one key element of the Internet of Things (IoT). Especially concepts for position estimation when Global Navigation Satellite Systems (GNSS) are unavailable have moved into the focus. One crucial component for localization systems in general and precise runtime-based positioning, in particular, is the necessity of ultra-precise clock synchronization between the receiving base stations. Our work presents a software-based approach for the wireless synchronization of spatially separated base stations using a low-cost off-the-shelf frontend architecture. The proposed system estimates the time synchronization, sampling clock offset, and carrier frequency offset using broadcast signals as Signals of opportunity.In this paper, we derive the theoretical lower bound for the estimation variance according to the Modified Cramer-Rao Bound. We show that a theoretical time synchronization accuracy in the range of ps and a frequency synchronization precision in the range of milli-Hertz is achievable. An algorithm is presented that estimates the desired parameter based on evaluating the Cross-Correlation Function between base stations. Initial measurements are conducted in a real-world environment. It is shown that the presented estimator nearly reaches the theoretical bound within a time and frequency synchronization accuracy of down to 200 ps and 6 mHz, respectively.



https://doi.org/10.1109/IPIN57070.2023.10332486
Chaudhury, Nandan Dutta; Berkelmann, Lukas; Jannsen, Bert; Robert, Jörg
On vehicular model reduction for antenna simulation using spherical wave expansion. - In: 2023 IEEE International Symposium on Antennas and Propagation (and USNC-URSI Radio Science Meeting), (2023), S. 935-936

The performance of a vehicular antenna is greatly affected by the vehicle body. Thus, it is imperative to simulate the automotive antenna in its installed state. The large electrical size of the vehicle often necessitates a high requirement on computer resources and a long simulation time. In this regard, a mathematically robust method for vehicular simulation model reduction using the Spherical Wave Expansion (SWE) theory is proposed in this paper. The applicability of the method has been demonstrated with an example consisting of a Hertzian dipole antenna integrated to the side mirror of a car.



https://doi.org/10.1109/USNC-URSI52151.2023.10238108
Neumüller, Clemens; Robert, Jörg; Heuberger, Albert
Convolving hyper-Erlang with hyper-exponential distributions using linear algebra. - In: ICoMS '22, (2022), S. 1-6

In this paper, the sum of a hyper-Erlang and a hyper-exponential distributed random variables is analyzed. Although tedious, the resulting random variable’s probability density function (PDF) can be obtained through convolution of its summands’ PDFs. Alternatively, the resulting distribution can be stated directly in terms of a phase-type distribution. However, computing its PDF can still be very costly and this representation gives little insight on the distribution. It can be shown that the sum of both random variable is again hyper-Erlang distributed of incremented order and can therefore be described without requiring the matrix exponential function. We derive a closed form linear algebra expression for the probability weights of the sum’s hyper-Erlang distribution, which significantly reduces the computational complexity of evaluating its distribution.



https://doi.org/10.1145/3545839.3545840
Neumüller, Clemens; Robert, Jörg; Heuberger, Albert
SIMO frame acquisition of fragmented telegrams in interference channels. - In: 2022 IEEE Wireless Communications and Networking Conference (WCNC), (2022), S. 2679-2684

Telegram fragmentation can offer an advantage in high interference domains such as unlicensed bands, commonly used for low power wide area networks (LPWANs). When retransmission is not possible, it is crucial to acquire telegrams at the first shot in order to avoid data loss. These desired high sensitivity constraints in conjunction with the high interference probability require the development of a new type of detector. In this paper both the matched subspace detector (MSD) and the constant false alarm rate (CFAR) MSD are adopted to multiple antennas and extended to the detection of fragmented telegrams. Their performance is discussed and examined analytically and using the Monte Carlo method in the additive white Gaussian noise (AWGN) and interference channel.



https://doi.org/10.1109/WCNC51071.2022.9771845
Michael, Marcelo; Robert, Jörg; Neumüller, Clemens; Heuberger, Albert
IoT cloud RAN testbed for indoor localization based on LPWANs. - In: 2021 Eighth International Conference on Internet of Things, Systems, Management and Security (IOTSMS), (2021), insges. 6 S.

Indoor localization is a highly researched topic as applications such as asset tracking can provide an enormous benefit for users. As GPS is typically not available indoors, smart phones employ WiFi fingerprinting to locate themselves inside buildings. Such localization is also highly interesting in context of Internet of Things (IoT). Low Power Wide Area Networks (LPWAN) offer cost-effective and long-range connectivity for IoT. Employing this approach, LPWAN sensor nodes can be localized using the received signal level at multiple LPWAN receivers. For testing the performance of LPWAN fingerprinting and the development of new algorithms we developed and installed a network consisting of 21 LPWAN receiver stations on the area of the NuernbergMesse, i.e. the international fair of Nuremberg, Germany. The infrastructure is realized as Cloud RAN (Radio Access Network). This means that the receivers only digitize the channel and the actual decoding of the signals is realized in the Cloud. As a result, the infrastructure is able to support the localization of many state-of-the-art LPWAN system. Initial measurements show the high performance and flexibility of the system. This paper gives an overview of the developed network components and shows the initial measurement results.



https://doi.org/10.1109/IOTSMS53705.2021.9704996
Schadhauser, Michael; Robert, Jörg; Heuberger, Albert; Edler, Bernd
Spectrum segmentation techniques for Edge-RAN decoding in telemetry-based IoT networks. - In: IEMTRONICS International Conference, Toronto, Canada, (2021), insges. 8 S.

The possible fields of application for small sensor nodes are tremendous and still growing fast. Concepts like the Internet of Things (IoT), Smart City or Industry 4.0 adopt wireless sensor networks for environmental interaction or metering purposes. As they commonly operate in license-exempt frequency bands, telemetry transmissions of sensors are subject to strong interferences and possible shadowing. Especially in the scope of Low Power Wide Area (LPWA) communications, this scenario results in high computational effort and complexity for the receiver side to perceive the signals of interest. Therefore, this paper investigates means to an adequate segmentation of receive spectra for a partial spectrum exchange between base stations of telemetry-based IoT sensor networks. The distinct interchange of in-phase and quadrature (IQ) data could facilitate stream combining techniques to mask out interferences amongst other approaches. This shall improve decoding rates even under severe operation conditions and simultaneously limit the required data volume. We refer to this approach of a reception network as Edge-RAN (Random Access Network). To cope with the high data rates and still enable a base station collaboration, especially in wirelessly connected receiver mesh networks, different filter bank techniques and block transforms are examined, to divide telemetry spectra into distinct frequency sub-channels. Operational constraints for the spectral decomposition are given and different filter methodologies are introduced. Finally, suitable metrics are established. These metrics shall assess the performance of the presented spectrum segmentation schemes for the purpose of a selective partial interchange between sensor network receivers.



https://doi.org/10.1109/IEMTRONICS52119.2021.9422584