Projection-OTA, over-the-air testing by reconfigurable reflecting structures. - In: Focus on linking antennas and propagation with the automotive and 5G industries, (2021), insges. 5 S.
The bottleneck in OTA testing electrically large equipment is the large number of sources required for sufficient angular density. That is, if the sources are active. In that case, high-bandwidth, high-frequency equipment with excellent stability, processing power, and configurability is needed per antenna element. The costs of scaling up the current MIMO OTA configuration to higher frequencies and/or large equipment is prohibitive. In case passive radiators are used, the maximum control speed is determined by the maximum expected Doppler frequency. Such performance is order of magnitudes cheaper, even for large numbers of elements. In this contribution, we will present a new OTA concept that uses passively radiating reconfigurable structures and is inherently bi-directional. The concept that we call Projection-OTA, accommodates test objects in FR1 that are electrically large to very large and shows good prospects for emulating beam dynamics for testing 5G NR in FR2. Whether such passive structures will be made up by reflect arrays, meta-surfaces, or even intelligent surfaces is to be determined. We will discuss the prospects and limitations of this concept.
https://doi.org/10.23919/EuCAP51087.2021.9411326
Joint communication and radar sensing: an overview. - In: Focus on linking antennas and propagation with the automotive and 5G industries, (2021), insges. 5 S.
This paper provides an overview of recent developments in Joint Communication and Radar Sensing (JCRS) systems and networks. Our discussion will focus on radio system and network architectures that can be used for JCRS and on approaches to select, generate and process waveforms suitable for both communication and sensing. In addition, advantages and challenges of assembling a network out of several JCRS nodes are addressed. Finally, we give an outlook to possible applications of JCRS networks, which we see in autonomous driving and low altitude air traffic control.
https://doi.org/10.23919/EuCAP51087.2021.9411178
Realistic emulation of GNSS testing scenarios using 3D wave field synthesis in an OTA testbed. - In: Focus on linking antennas and propagation with the automotive and 5G industries, (2021), insges. 5 S.
While traditional testing methods as conducted and open field tests have their limitations in terms of realism and repeatability of the scenario's conditions, Over-the-Air (OTA) testing enhances the way that GNSS and mobile communications systems with integrated antennas are tested, since it provides the freedom to accurately emulate an impinging wave with arbitrary polarization and direction radiated from any source/reflection such as GNSS satellites and terrestrial base stations. Therefore, real world scenarios can be precisely reproduced with total control of the environment's conditions. In this context, this paper describes the process to implement full polarimetric 3D Wave Field Synthesis (WFS) in an OTA testbed, from the principle to characterize the electromagnetic (EM) field in three dimensions to the system calibration and correspondent verification measurements inside the anechoic chamber, which will provide a deeper insight on the quality and reliability of the EM field for testing purposes.
https://doi.org/10.23919/EuCAP51087.2021.9411259
5G mm-wave over-the-air measurements of an agile multi-beam front-end. - In: 2020 50th European Microwave Conference, (2021), S. 153-156
A millimeter wave agile multi-beam front-end with an integrated 4 by 1 antenna array for 5th generation wireless communications is analyzed by antenna and digital communication measurements. The front-end core comprises a compact low-temperature co-fired ceramic multilayer module with a foot-print area of 74 mm × 74 mm. An over-the-air gain of 50.4 dB and a noise figure of 4.9 dB were measured. Link measurements with broadband single-carrier QAM and OFDM signals result in a data rate of 3.2 Gb/s for 400 MHz bandwidth SC-256QAM modulation with 1.2% error vector magnitude of the front-end determined by a detailed analysis.
https://doi.org/10.23919/EuMC48046.2021.9338199
A V-band vector modulator based phase shifter in BiCMOS 0.13 [my]m SiGe technology. - In: 2020 15th European Microwave Integrated Circuits Conference, (2021), S. 65-68
https://ieeexplore.ieee.org/document/9337367
The performance measurement of the 60GHz mmWave module for IoRL network. - In: 2020 IEEE International Symposium on Broadband Multimedia Systems and Broadcasting (BMSB), (2020), insges. 5 S.
As one of the key features in 5G network, Millimeter wave (mmWave) technology can provide the ultra-wide bandwidth to support higher data rate. However, for high frequency band, mmWave signal still suffers from the high pathloss, the multipath fading and the signal blockage issue, especially in the indoor environment. For different application scenarios, the channel conditions and quality of services (QoS) are quite different. Therefore, it is essential to investigate the impact of the mmWave channel on the system performance. This paper investigates and measures the performance of a 60GHz mmWave module that is exploited for the downlink and uplink high data rate transmission in the Internet of Radio-Light (IoRL) project. The coverage area and the throughput of the mmWave module is estimated by measuring the error vector magnitude (EVM) of received signals with different transmitter (TX) and receiver (RX) angles and at different locations in a laboratory. In this paper, the measurement environment and system setup are introduced. After that, the waveform design for the measurement is also discussed. The measurement results show that this 60GHz mmWave module can provide an acceptable performance only in some cases, which restricts its application scenarios.
https://doi.org/10.1109/BMSB49480.2020.9379731
A framework for developing algorithms for estimating propagation parameters from measurements. - In: 2020 IEEE Globecom workshops (GC Wkshps), (2020), insges. 6 S.
A framework is proposed for developing and evaluating algorithms for extracting multipath propagation components (MPCs) from measurements collected by sounders at millimeter-wave (mmW) frequencies. To focus on algorithmic performance, an idealized model is proposed for the spatial frequency response of the propagation environment measured by a sounder. The input to the sounder model is a pre-determined set of MPC parameters that serve as the "ground truth". A three-dimensional angle-delay (beamspace) representation of the measured spatial frequency response serves as a natural domain for implementing and analyzing MPC extraction algorithms. Metrics for quantifying the error in estimated MPC parameters are introduced. Initial results are presented for a greedy matching pursuit algorithm that performs a least-squares (LS) reconstruction of the MPC path gains within the iterations. The results indicate that the simple greedy-LS algorithm has the ability to extract MPCs over a large dynamic range, and suggest several avenues for further performance improvement through extensions of the greedy-LS algorithm as well as by incorporating features of other algorithms, such as SAGE and RIMAX.
https://doi.org/10.1109/GCWkshps50303.2020.9367404
Bi-static delay-Doppler reference for cooperative passive vehicle-to-X radar applications. - In: IET microwaves, antennas & propagation, ISSN 1751-8733, Bd. 14 (2020), 14, S. 1749-1757
Automotive radar systems are indispensable for advanced driver assistance systems and traffic safety. Besides existing monostatic radar techniques, bi-static radar sensing like passive coherent location offers additional options to improve the radar visibility of vulnerable road users. Regarding the testing and evaluation of signal processing algorithms including parameter estimation, it is essential to provide electromagnetically shielded and reproducible measurement conditions, in addition to field tests in real traffic scenarios. This study describes the possibility to emulate relevant performance parameters for bi-static radar scenarios in the frequency range from 1 GHz to 6 GHz in a metal-shielded semi-anechoic chamber. Of special interest are the bi-static angle between transmitter, target, and receiver, and the resulting bi-static Doppler frequencies of a realistic vehicular traffic scenario. According to the concept of cooperative passive coherent location, Doppler scattering measurements are presented and compared to electromagnetic simulations. The authors find promising agreement between measured and ground truth data in the delay-Doppler spectrum.
https://doi.org/10.1049/iet-map.2019.0991
Bi-static reflectivity patterns of vulnerable road users in the C-V2X frequency range. - In: 2020 IEEE Radar Conference (RadarConf20), (2020), insges. 6 S.
https://doi.org/10.1109/RadarConf2043947.2020.9266284
Hardware architecture for ultra-wideband channel impulse response measurements using compressed sensing. - In: 28th European Signal Processing Conference (EUSIPCO 2020), (2020), S. 1663-1667
We propose a compact hardware architecture for measuring sparse channel impulse responses (IR) by extending the M-Sequence ultra-wideband (UWB) measurement principle with the concept of compressed sensing. A channel is excited with a periodic M-sequence and its response signal is observed using a Random Demodulator (RD), which observes pseudo-random linear combinations of the response signal at a rate significantly lower than the measurement bandwidth. The excitation signal and the RD mixing signal are generated from compactly implementable Linear Feedback Shift registers (LFSR) and operated from a common clock. A linear model is derived that allows retrieving an IR from a set of observations using Sparse-Signal-Recovery (SSR). A Matrix-free model implementation is possible due to the choice of synchronous LFSRs as signal generators, resulting in low computational complexity. For validation, real measurement data of a time-variant channel containing multipath components is processed by simulation models of our proposed architecture and the classic M-Sequence method. We show successful IR recovery using our architecture and SSR, outperforming the classic method significantly in terms of IR measurement rate. Compared to the classic method, the proposed architecture allows faster measurements of sparse time-varying channels, resulting in higher Doppler tolerance without increasing hardware or data stream complexity.
https://doi.org/10.23919/Eusipco47968.2020.9287454