From 3D point cloud data to ray-tracing multi-band simulations in industrial scenario. - In: 2022 IEEE 95th Vehicular Technology Conference (VTC2022-Spring), (2022), insges. 5 S.
In this paper, we present the ray tracing (RT) simulation in the 3D model of one highly dense clutter industrial hall, which is scanned by laser scanner and reconstructed based on accurate point cloud. The whole processing chain from the scanning of the physical environment to running the simulation is presented in detail. To validate the simulation results, the synthetic channel characteristics and large-scale parameters, including delay spread (DS), angular spread (AS) and path loss (PL), are compared with those obtained from channel sounding measurement in both LOS and NLOS cases, at 6.75 GHz, 30 GHz and 60 GHz. The simulation results show that some scatters are significant in all bands and may be well identified and tracked. This indicates that our target to generate a deterministic channel model or a hybrid channel model at multi-band for industrial scenario may be possible.
https://doi.org/10.1109/VTC2022-Spring54318.2022.9861002
Reliable deep learning based localization with CSI fingerprints and multiple base stations. - In: 2022 IEEE International Conference on Communications, (2022), S. 3214-3219
Deep learning (DL) methods have been recently proposed for user equipment (UE) localization in wireless communication networks, based on the channel state information (CSI) between a UE and multiple base stations (BSs) in the uplink. With the CSI from the available BSs, UE localization can be performed in different ways. On the one hand, a single neural network (NN) can be trained for the UE localization by considering the CSI from all the available BSs as one overall fingerprint of the user’s location. On the other hand, the CSI at each BS can be used to obtain an estimate of the UE’s position with a separate NN at each BS, and then the position estimates of all BSs are combined to obtain an overall estimate of the UE position. In this work, we show that UE localization with the latter approach can achieve a higher positioning accuracy. We propose to consider the uncertainty in the UE localization at each BS, such that overall UE’s position is determined by combining the position estimates of the different BSs based on the uncertainty at each BS. With this approach, a more reliable position estimate can be obtained in case of variations in the channel.
https://doi.org/10.1109/ICC45855.2022.9838535
LTCC patch antenna array for 5G mobile applications featuring embedded air cavities. - In: 2022 International Conference on Electronics Packaging (ICEP 2022), (2022), S. 139-140
A LTCC patch antenna array was designed and fabricated in Low Temperature Co-fired Ceramic (LTCC) multilayer technology using picosecond laser structuring for precise manufacturing of embedded air cavities and feeding structures, which are beneficial for the antenna RF performance. Moreover, free-standing feeding vias in the embedded air cavities were successfully implemented in LTCC technology that enable a very simple and low-loss feed at the antenna ports. The 2x2 dual-polarized patch antenna array with embedded air cavities and transitions was first characterized by reflection measurements. The measured center frequency of the antenna is about 29.5 GHz and a bandwidth of nearly 1 GHz was achieved.
https://doi.org/10.23919/ICEP55381.2022.9795485
Descending staircase detection for service robots based on M-sequence UWB radar. - In: 2021 18th European Radar Conference, (2022), S. 29-32
Service robotics is expected to be one of the central growth industries of this century. The technological key to this lies in the sufficient perception of the environment, even under difficult conditions, because mobile robots have to orientate themselves and navigate without collision under all circumstances. However, the safe detection of especially descending stairs is a big challenge so far. In this paper, the results of descending staircase detection using UWB radar are shown. The individual steps of the signal processing from signal preparation to multi-target tracking are briefly explained and an outlook is given on how to classify a staircase based on the results. For all investigated stairs the edge of the first step could be detected reliably from a distance of 1.5 m and multiple steps are distinguishable as well.
https://doi.org/10.23919/EuRAD50154.2022.9784493
Localization and navigation of service robots by means of M-sequence UWB radars. - In: 2021 18th European Radar Conference, (2022), S. 189-192
The use of service robots has become much more relevant in industry and retail in recent years. To be of best possible benefit to humans, an autonomous motion ability of the service robots is of central importance. This requires that the robot can perceive its surroundings as precisely as possible by using different sensors and their fusion. In contrast to optical sensors, an UWB sensor can, for example, detect small and almost invisible objects such as glass panes with high range resolution. In this paper, a signal processing chain for detection of the environment with M-sequence UWB sensors is proposed. The proposed chain includes pulse reconstruction based on calibration measurements, background subtraction, object detection based on CFAR techniques, and multi-target tracking based on the Kalman filter and the nearest-neighbor approach.
https://doi.org/10.23919/EuRAD50154.2022.9784511
RF performance of USRP TwinRX daughterboard under influence of strong interferers. - In: 16th European Conference on Antennas and Propagation, (2022), insges. 5 S.
In this paper, we investigate the sensitivity of the software-defined radio (SDR) universal software radio peripheral (USRP) X310 with a TwinRX daughterboard to strong interferers. In a conducted test setup, the signal-to-interference-plus-noise ratio (SINR) is measured under the influence of a mock-up Long-Term Evolution (LTE) base station. The frequency of the interferer is varied to analyze the effects over a wide frequency band, whereby a distinction is made between signals inside and outside the intermediate frequency (IF) band. The former can cause clipping at the analog-to-digital converter (ADC), while the latter are to be suppressed in the analog part of the software-defined radio. Here, leakage and higher-order mixing products make the receiver sensitive to spurious frequencies, whereby the performance degradation is particularly noticeable near the first intermediate frequency (IF1) of 1.25 GHz. At this point, even an interference signal with −28 dBm peak envelope power (PEP) causes an SINR loss of 3 dB.
https://doi.org/10.23919/EuCAP53622.2022.9769615
A frequency domain approach for estimating the angular dependent delay of an UWB antenna. - In: 16th European Conference on Antennas and Propagation, (2022), insges. 5 S.
The procedure of estimating the angular dependent delay of an Ultra Wideband (UWB) antenna, directly in frequency domain, is presented. It is shown that in this approach any occurrences that can lead to inaccurate results, such as the windowing effect, can be entirely avoided. It alleviates the need to design a specific pulse, since the transfer function can be obtained by a frequency sweep. Moreover, polarization mismatch is accounted in the analysis. To this end, an UWB monopole antenna is designed and it is simulated with time and frequency domain solvers. The simulation results demonstrate that only frequency domain analysis is sufficient for the delay estimation. The outcome of this work provides a clear procedure for obtaining the angular dependent delay of an antenna in an accurate way.
https://ieeexplore.ieee.org/document/9769534
From sub-6 GHz to mm-wave: simultaneous multi-band characterization of propagation from measurements in industry scenarios. - In: 16th European Conference on Antennas and Propagation, (2022), insges. 5 S.
In the present paper we introduce simultaneous multi-band measurements at sub-6 GHz and two mm-wave bands with the objective of characterizing propagation for multi-band channel modelling purposes in industry scenarios. The marginal power profiles show that the dominant scatterers are common in the different frequencies. In addition, a relation of decreasing average delay and angular spreads with increasing frequency is observed. The different measured parameters are contrasted with the 3GPP model for indoor factories.
https://ieeexplore.ieee.org/document/9768944
Level measurement of low-permittivity material using an M-sequence UWB radar. - In: 16th European Conference on Antennas and Propagation, (2022), insges. 5 S.
Due to increasingly complex and automated manufacturing processes, the demands on the control parameters of these processes are also increasing. One parameter is the fill quantity of e.g. liquids in production plants, whose precise determination is of ever growing importance. Up to now, the exact level determination under difficult conditions, such as high ambient temperatures, has been a particular challenge. This paper demonstrates a novel method by which an M-sequence UWB radar can determine levels of low-permittivity materials in small metal containers. For this purpose, hot melt is used as an example. Thus, the influence of large temperature differences on the long-term stability of level measurement can also be investigated. The measurements show that the level of hot melt can be measured long-term stable with an accuracy of better than 3 mm.
https://ieeexplore.ieee.org/document/9769405
Verification of THz channel sounder and delay estimation with over-the-air multipath artifact. - In: 16th European Conference on Antennas and Propagation, (2022), insges. 5 S.
In the present paper we introduce the empirical results of measurements with an over-the-air based propagation artifact for verification and validation of sub-THz and THz channel sounders and parameter estimation algorithms. This experiment produces a fixed number of multipath components with traceable propagation properties in the different domains that can be used to test resolution and performance. Because of the inherent characteristics of the measurement hardware, we have introduced an adaptation on a parametric high resolution estimation algorithm to account the imperfections of the channel sounder. The results have shown to account for a relative good performance of the sounder and the tested parametric and non-parametric estimation algorithms.
https://ieeexplore.ieee.org/document/9769269