Demonstration and validation of a 3D wave field synthesis setup for multiple GNSS satellite emulation via over-the-air testing. - In: AMTA 2023 proceedings, (2023), insges. 10 S.
Wireless devices supporting global navigation satellite systems (GNSS) services have become an essential tool in different areas of technology such as agriculture, construction, automotive, etc. Therefore the performance and reliability of such devices are important aspects that need to be addressed in the testing stage during the development of the units. The integration of the Over-the-Air (OTA) testing method with the 3D Wave Field Synthesis (3DWFS) technique offer not only the benefit of having tests under controllable and repeatable conditions but also the ability to recreate complex and realistic scenarios in a controlled environment with full polarimetric support for the testing of wireless devices. This contribution applies this technology to emulate a GNSS scenario within an anechoic chamber. For the results validation, a realistic GNSS outdoor scenario was recorded and compared with the emulated scenario where 3DWFS was applied for each individual satellite. This represents a significant step for the GNSS community and also for the future development and testing of wireless devices.
https://doi.org/10.23919/AMTA58553.2023.10293372
Sensing resources reduction for vehicle detection with integrated sensing and communications. - In: 2023 IEEE 97th Vehicular Technology Conference (VTC2023-Spring), (2023), insges. 5 S.
Integrated Sensing and Communications (ISAC) aims at incorporating radar and communications functionalities into a single system, achieving higher spectral efficiency through their joint operation. This paper proposes a methodology for reducing resource elements and scanning beams used in the target detection stage of ISAC. Building upon the well-known symbol domain Orthogonal Frequency Division Multiplexing (OFDM) ISAC processing algorithm, its relevant characteristics and limits are considered to minimize the periodicity of sensing resource elements. Moreover, a methodology for finding the required beams to sense a scenario using the radar range equation in a link-budget analysis is proposed and later illustrated via simulations. The simulations show that it is possible to cover a road scenario using a limited number of beams and resource elements from a New Radio (NR) OFDM frame.
https://doi.org/10.1109/VTC2023-Spring57618.2023.10199358
Dynamic delay-dispersive UWB-radar targets: modeling and estimation. - In: IEEE transactions on antennas and propagation, ISSN 1558-2221, Bd. 71 (2023), 8, S. 6814-6829
This publication proposes a parametric data model and a gradient-based maximum likelihood estimator suitable for the description of delay-dispersive responses of multiple dynamic ultrawideband (UWB)-radar targets. The target responses are estimated jointly with the global target parameters range and velocity. The large relative bandwidth of UWB has consequences for model-based parameter estimation. On the one hand, the Doppler effect leads to a dispersive response in the Doppler spectrum and to a coupling of the target parameters that both need to be considered during modeling and estimation. On the other hand, the shape of an extended target results in a dispersive response in range, which can be resolved by the radar resolution. We consider this extended response as a parameter of interest, e.g., for the purpose of target recognition. Hence, we propose an efficient description and estimation of it by a finite impulse response (FIR) structure only imposing a restriction on the target’s dispersiveness in range. We evaluate the approach on simulations, compare it to state-of-the-art solutions, and provide a validation of the FIR model on measurements of a static scenario.
https://doi.org/10.1109/TAP.2023.3287672
Fill level measurement of low-permittivity material using an M-sequence UWB radar. - In: International journal of microwave and wireless technologies, ISSN 1759-0795, Bd. 15 (2023), 8, S. 1299-1307
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 of 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 to be long-term stable with an accuracy of better than 3 mm. Furthermore, the precise determination of the empty state is highly important for many applications. For this reason, this paper shows a method for determining the empty state without complex calibration procedures. For the empty level indication, an accuracy of up to 0.5 mm could be achieved for molten hot glue and 3% of the tank volume, independent of the shape or aggregate state of the medium.
https://doi.org/10.1017/S1759078723000739
Efficient phased array radiation pattern evaluation for 5G and SatCom On-The-Move (SOTM) applications. - In: 17th European Conference on Antennas and Propagation (EuCAP 2023), (2023), insges. 5 S.
In satellite communications, it is becoming challenging to provide the tracking performance which is required for Non-Geostationary Orbit (NGSO) constellations with the traditional Satellite Communications (SatCom) On The Move (SOTM) terminal structure which employs bulky parabolic antennas. On the other hand, in terrestrial networks, the single omnidirectional communication with User Equipment (UE) does not provide enough throughput to fulfill the need for higher speed connections. As a consequence, manufacturers started to invest in developing new terminals which use phased array antennas to enable beamforming to increase the directivity and null the interference in terrestrial networks and to provide rapid tracking performance as well as seamless handovers in SOTM. However, this generates new challenge as these antennas change beam patterns depending on the beam steering angle. It is not trivial to evaluate the performance of beamforming antennas since the measurement of the high number of beam patterns that the phased array can form in all directions is time consuming. In this paper, we propose a methodology to measure a large number of beam patterns of a phased array antenna in a more time efficient approach compared to traditional antenna measurement methods. The measured patterns can be used to evaluate the antenna performance and capabilities in different conditions and verify the terminal ability to fulfill the requirements specified by the standards.
https://doi.org/10.23919/EuCAP57121.2023.10132956
Configurable pseudo noise radar imaging system enabling synchronous MIMO channel extension. - In: Sensors, ISSN 1424-8220, Bd. 23 (2023), 5, 2454, insges. 27 S.
In this article, we propose an evolved system design approach to ultra-wideband (UWB) radar based on pseudo-random noise (PRN) sequences, the key features of which are its user-adaptability to meet the demands provided by desired microwave imaging applications and its multichannel scalability. In light of providing a fully synchronized multichannel radar imaging system for short-range imaging as mine detection, non-destructive testing (NDT) or medical imaging, the advanced system architecture is presented with a special focus put on the implemented synchronization mechanism and clocking scheme. The core of the targeted adaptivity is provided by means of hardware, such as variable clock generators and dividers as well as programmable PRN generators. In addition to adaptive hardware, the customization of signal processing is feasible within an extensive open-source framework using the Red Pitaya® data acquisition platform. A system benchmark in terms of signal-to-noise ratio (SNR), jitter, and synchronization stability is conducted to determine the achievable performance of the prototype system put into practice. Furthermore, an outlook on the planned future development and performance improvement is provided.
https://doi.org/10.3390/s23052454
Fill level measurements using an M-sequence UWB radar. - In: International journal of microwave and wireless technologies, ISSN 1759-0795, Bd. 15 (2023), 1, S. 74-81
Due to increasingly complex and automated manufacturing processes, the demands on the control parameters of these processes are also increasing. In many applications, such a parameter is the fill quantity, whose precise determination is of ever growing importance. This paper shows with which accuracy and precision an M-sequence ultra-wideband radar can determine levels in small metallic and non-metallic containers with contact-based and contactless measurements. First, the principle of level measurement using guided wave radar is explained and the measurement setup is described. Afterward, the measurement results are shown and discussed. The measurements show that the level can be measured with an accuracy of better than 0.5 mm. In addition, level fluctuations can be detected with a precision of 3 μm. Based on the results of the guided wave radar, the possibilities of volumetric contactless measurement using an electrically small patch antenna are discussed. A particular challenge in contactless level measurement is the high number of multipath components, which strongly influence the accuracy. In addition, there are near-field effects when measuring close to the antenna. Exploiting these near-field effects, an additional method to accurately determine the full state of the container is investigated.
https://doi.org/10.1017/S1759078722000502
Labeling custom indoor point clouds through 2D semantic image segmentation. - In: 2022 Sixth IEEE International Conference on Robotic Computing, (2022), S. 261-264
For effective Computer Vision (CV) applications, one of the difficult challenges service robots have to face concerns with complete scene understanding. Therefore, various strategies are employed for point-level segregation of the 3D scene, such as semantic segmentation. Currently Deep Learning (DL) based algorithms are popular in this domain. However, they require precisely labeled ground truth data. Generating this data is a lengthy and expensive procedure, resulting in a limited variety of available data. On the contrary, the 2D image domain offers labeled data in abundance. Therefore, this study explores how we can achieve accurate labels for the 3D domain by utilizing semantic segmentation on 2D images and projecting the estimated labels to the 3D space via the depth channel. The labeled data may then be used for vision related tasks such as robot navigation or localization.
https://doi.org/10.1109/IRC55401.2022.00050
Emulation of electromagnetic plane waves for 3D antenna pattern estimation. - In: 2022 IEEE 96th Vehicular Technology Conference:(VTC 2022-Fall), (2022), insges. 6 S.
With the fast development of wireless devices, over-the-air (OTA) testing is becoming the preferred method among developers and manufacturers of wireless equipment. The ability to recreate a scenario under controllable and repeatable conditions keeps the method under constant development, providing new features that increase the realism during the tests. A recent proof of that is the integration of 3D wave field synthesis (3DWFS) to OTA testing, which becomes a significant step to accurately emulate wireless scenarios within a controlled environment.In this context, this contribution improves the OTA system calibration for 3DWFS; efficiently increasing the emulation quality of electromagnetic plane waves impinging from any angular position within an anechoic chamber. In fact, this enhancement implicitly delivers a new method for accurate estimation of the antenna radiation pattern in 3D. This is not only a highly demanded application among antenna manufacturers but in this case also proves the validity of the results and consolidates the integration of 3DWFS to OTA testing.
https://doi.org/10.1109/VTC2022-Fall57202.2022.10013008
Enhancement of vision-based 3D reconstruction systems using radar for smart farming. - In: 2022 IEEE International Workshop on Metrology for Agriculture and Forestry, (2022), S. 155-159
Digital field recordings are central to most precision agriculture systems since they can replicate the physical environment and thus monitor the state of an entire field or individual plants. Using different sensors, such as cameras and radar, data can be collected from various domains. Through the combination of radio wave propagation and visible light phenomena, it is possible to enhance, e.g., the optical condition of a fruit with internal parameters such as the water content. This paper proposes a method to correct sensor errors to perform data fusion. As an example, we observe a watermelon with camera and radar sensors and present a system architecture for the visualization of both sensors. For this purpose, we constructed a handheld platform on which both sensors are mounted. In our report, the radar is analyzed in terms of systematic and stochastic errors to formulate an angle-dependent mapping function for error correction. It is successfully shown that camera and radar data are correctly assigned with a watermelon used as a target object, demonstrated by a 3D reconstruction. The proposed system shows promising results for sensor overlay, but radar data remain challenging to interpret.
https://doi.org/10.1109/MetroAgriFor55389.2022.9964699
Time-domain analysis of ultra-wideband scattering properties of fruits. - In: 2022 19th European Radar Conference, (2022), S. 77-80
In the present paper we evaluate scattering properties of fruits measured with a short-range Ultra-Wideband radar. This is part of our investigation how effectively such a radar can be used to infer information such as fruit biomass or ripeness in an agricultural environment. The covered frequency band spans from 1.4 to 5.6 GHz. We analyze measured impulse responses of a watermelon, a grapefruit, and an apple with respect to a dependency on the distance between radar and fruit and the observation angle i.e., rotation of the fruit. Measurements are performed under laboratory conditions, however, we analyze the data considering a pre-harvest analysis on a field. It becomes apparent that an analysis of the dispersed dominant reflection of the peel is most promising. Due to the natural growth and hence anisotropy of the fruits, we conclude to average over multiple monostatic observation angles to reduce the natural variations of e.g. the scattered power.
https://doi.org/10.23919/EuRAD54643.2022.9924720
Enable SDRs for real-time MIMO channel sounding featuring parallel coherent Rx channels. - In: 2022 IEEE 95th Vehicular Technology Conference:(VTC2022-Spring), (2022), insges. 5 S.
A parallel receiver architecture for multiple input multiple output (MIMO) channel sounding application is presented with a software-defined radio (SDR)-based field-programmable gate array (FPGA) implementation. The receiver covers phase coherent reception via shared local oscillator (LO) and reference clock, a timing scheme synchronous to the antenna switching at the transmitter, and an integrated automatic gain control (AGC) in all receive channels. It is built with SDRs (NI USRP-2955, X310 series with TwinRx daughterboards). The use of these off-the-shelf hardware components reduces the costs of the sounding system. The FPGA implementation together with the system parameters of the chosen hardware allows a minimum AGC update interval of approx. 44.38 μs. Our setup demonstrates the applicability of state-of-the-art SDRs as a sounding system for continuous acquisition of the time variant, space, and frequency selective radio propagation channel.
https://doi.org/10.1109/VTC2022-Spring54318.2022.9860841
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
5G new radio physical downlink control channel reliability enhancements for multiple transmission-reception-point communications. - In: IEEE access, ISSN 2169-3536, Bd. 10 (2022), S. 97394-97407
Non-coherent transmission from multiple transmission-reception-points (TRPs), i.e., base stations, or base station panels to a user equipment (UE) is exploited in 5G New Radio (NR) to improve downlink reliability and cell-edge throughput. Ultra reliable low-latency communications (URLLC) and enhanced Mobile BroadBand (eMBB) are prominent target use-cases for multi-TRP or multi-panel transmissions. In Third-Generation Partnership Project (3GPP) Release 17 specifications, multi-TRP-based transmissions were specified for the physical downlink control channel (PDCCH) specifically to enhance its reliability and robustness. In this work, a comprehensive account of various multi-TRP reliability enhancement schemes applicable for the 5G NR PDCCH, including the ones supported by the 3GPP Release 17 specifications, is provided. The impact of the specifications for each scheme, UE and network complexity and their utility in various use-cases is studied. Their error performances are evaluated via link-level simulations using the evaluation criteria agreed in the 3GPP proceedings. The 3GPP-supported multi-TRP PDCCH repetition schemes, and the additionally proposed PDCCH repetition and diversity schemes are shown to be effective in improving 5G NR PDCCH reliability and combating link blockage in mmWave scenarios. The link-level simulations also provide insights for the implementation of the decoding schemes for the PDCCH enhancements under different channel conditions. Analysis of the performance, complexity and implementation constraints of the proposed PDCCH transmission schemes indicate their suitability to UEs with reduced-capability or stricter memory constraints and flexible network scheduling.
https://doi.org/10.1109/ACCESS.2022.3206027
Phase estimation of single tones next to modulated signals in the medium frequency R-mode system. - In: IEEE access, ISSN 2169-3536, Bd. 10 (2022), S. 73309-73316
Position, navigation, and timing information are critical to today’s infrastructures; as a result, the possibility of estimating ranges is being explored in more and more radio systems. One way to achieve this is to extend the modulation with time-synchronised aiding carriers and to estimate their phase at the receiver side. In this paper, we present two ways to minimise the negative influence of the modulation on the phase estimation. We show that the classical maximum likelihood estimator is still an efficient estimator for our problem, using a medium-frequency R-Mode signal as an example, and is therefore used in receiver designs. We then describe two possible ways to precondition the signal to increase the accuracy for short observations. As a first approach, we describe how window functions can positively change the signal-to-noise ratio for our estimation. As a second approach, we show the use of a narrowband bandpass filter. Finally, we show that these approaches, applied to real measurements, improve the variance of the estimate by up to two orders of magnitude.
https://doi.org/10.1109/ACCESS.2022.3190544
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
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
Fast gain switching on TwinRX USRPs. - In: 16th European Conference on Antennas and Propagation, (2022), insges. 5 S.
In this paper, we investigate the gain switching performance of the software-defined radio (SDR) universal software radio peripheral (USRP) X310 with the TwinRX daughterboard and propose a method to optimize it for fast transitions. This receiver uses a complex structure of two switchable amplifiers and two digital step attenuators to realize the wide gain setting range of up to 92 dB. Our measurements of the settling time show that the bulk of transitions between two gain settings take below 1.5 µs, but some require more than 50 µs, caused by the power-up of the switchable amplifiers. Based on this knowledge, we propose a modified switching regime, in which the amplifiers are not toggled in time-critical phases, e.g., during a running measurement, so that a transition time of 1.5 µs can be reliably realized. Thus, a gain switching range of 62 dB is achieved, within which, for example, a fast automatic gain control can be realized.
https://doi.org/10.23919/EuCAP53622.2022.9769488
Open sub-granting radio resources in overlay D2D-based V2V communications. - In: EURASIP journal on wireless communications and networking, ISSN 1687-1499, Bd. 2022 (2022), 46, S. 1-29
Richtiger Name des Verfassers: Dariush Mohammad Soleymani
Capacity, reliability, and latency are seen as key requirements of new emerging applications, namely vehicle-to-everything (V2X) and machine-type communication in future cellular networks. D2D communication is envisaged to be the enabler to accomplish the requirements for the applications as mentioned earlier. Due to the scarcity of radio resources, a hierarchical radio resource allocation, namely the sub-granting scheme, has been considered for the overlay D2D communication. In this paper, we investigate the assignment of underutilized radio resources from D2D communication to device-to-infrastructure communication, which are moving in a dynamic environment. The sub-granting assignment problem is cast as a maximization problem of the uplink cell throughput. Firstly, we evaluate the sub-granting signaling overhead due to mobility in a centralized sub-granting resource algorithm, dedicated sub-granting radio resource (DSGRR), and then a distributed heuristics algorithm, open sub-granting radio resource (OSGRR), is proposed and compared with the DSGRR algorithm and no sub-granting case. Simulation results show improved cell throughput for the OSGRR compared with other algorithms. Besides, it is observed that the overhead incurred by the OSGRR is less than the DSGRR while the achieved cell throughput is yet close to the maximum achievable uplink cell throughput.
https://doi.org/10.1186/s13638-022-02128-0
Make some noise: energy-efficient 38 Gbit/s wide-range fully-configurable linear feedback shift register. - In: SMACD / PRIME 2021, (2021), S. 384-387
https://ieeexplore.ieee.org/document/9547997
Every clock counts - 41 GHz wide-range integer-N clock divider. - In: SMACD / PRIME 2021, (2021), S. 388-391
https://ieeexplore.ieee.org/document/9547998
Positioning with medium frequency R-Mode. - In: Navigation, ISSN 2161-4296, Bd. 68 (2021), 4, S. 829-841
R-Mode is a terrestrial navigation system under development for the maritime domain that provides backup in case of a GNSS outage. This paper describes the first test results for real-time positioning on board a ship using medium frequency R-Mode signals. The estimation and positioning algorithms used are described in detail and it is shown how they are integrated into the R-Mode receiver developed by the German Aerospace Center. Moreover, during two daytime experiments with lower and higher dynamic movements of a ship in the Baltic Sea, we were able to achieve a 95% horizontal positioning accuracy of better then 12 m in the center of three R-Mode transmitters. This demonstrates the first time that the medium frequency R-Mode has provided positioning at sea.
https://doi.org/10.1002/navi.450
Frequency subsampling of ultrasound nondestructive measurements: acquisition, reconstruction, and performance. - In: IEEE transactions on ultrasonics, ferroelectrics, and frequency control, ISSN 1525-8955, Bd. 68 (2021), 10, S. 3174-3191
In ultrasound nondestructive testing (NDT), a widespread approach is to take synthetic aperture measurements from the surface of a specimen to detect and locate defects within it. Based on these measurements, imaging is usually performed using the synthetic aperture focusing technique (SAFT). However, SAFT is suboptimal in terms of resolution and requires oversampling in the time domain to obtain a fine grid for the delay-and-sum (DAS). On the other hand, parametric reconstruction algorithms give better resolution, but their usage for imaging becomes computationally expensive due to the size of the parameter space and a large amount of measurement data in realistic 3-D scenarios when using oversampling. In the literature, the remedies to this are twofold. First, the amount of measurement data can be reduced using state-of-the-art sub-Nyquist sampling approaches to measure Fourier coefficients instead of time-domain samples. Second, parametric reconstruction algorithms mostly rely on matrix-vector operations that can be implemented efficiently by exploiting the underlying structure of the model. In this article, we propose and compare different strategies to choose the Fourier coefficients to be measured. Their asymptotic performance is compared by numerically evaluating the Cramér-Rao bound (CRB) for the localizability of the defect coordinates. These subsampling strategies are then combined with an l1-minimization scheme to compute 3-D reconstructions from the low-rate measurements. Compared to conventional DAS, this allows us to formulate a fully physically motivated forward model matrix. To enable this, the projection operations of the forward model matrix are implemented matrix-free by exploiting the underlying two-level Toeplitz structure. Finally, we show that high-resolution reconstructions from as low as a single Fourier coefficient per A-scan are possible based on simulated data and measurements from a steel specimen.
https://doi.org/10.1109/TUFFC.2021.3085007
Energy-efficient autonomous resource selection for power-saving users in NR V2X. - In: 2021 IEEE 32nd Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC), (2021), S. 972-978
Energy efficiency has recently drawn significant attention in diverse applications, such as vehicle-to-everything (V2X) communications. This paper investigates a joint energy efficiency and sum-rate maximization problem in autonomous resource selection in the 5G new radio (NR) vehicular communication while catering for reliability and latency requirements. An autonomous resource allocation problem is formulated as a ratio of sum-rate to energy consumption, where the objective is to maximize the total energy efficiency of power-saving users subject to the reliability and latency requirements. The energy efficiency problem is a mixed-integer programming optimization problem that is computationally complex when the number of users increases. Therefore, a heuristic algorithm, density of traffic-based resource allocation (DeTRA), is proposed to solve the problem. The traffic density per traffic type is considered a metric to split the radio resources and trigger an appropriate resource selection strategy. The simulation results show that the proposed algorithm outperforms the existing schemes in terms of energy efficiency.
https://doi.org/10.1109/PIMRC50174.2021.9569365
Verification of dual-polarized ultra-wideband channel sounder for THz applications. - In: 2021 IEEE 32nd Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC), (2021), insges. 5 S.
The lower THz bands are foreseen as candidates to achieve the data-rates demanded in the sixth generation (6G) of wireless communications. Hence, multiple measurements for characterization of propagation at these frequencies in different scenarios are being conducted all around the world. This also impulses activities on standardization of measurement equipment and methodologies to define common practices and make measurements from different actors comparable. Therefore, in the present paper we investigate the accuracy of a dual-polarized ultra-wideband channel sounder in the time, angular, and polarization domains by means of a verification methodology based on interferometry.
https://doi.org/10.1109/PIMRC50174.2021.9569491
Enable software-defined radios for real-time MIMO channel sounding. - In: To measure is to know, (2021), insges. 5 S.
This paper describes a field-programmable gate array (FPGA)-based implementation of a switched multiple input multiple output (MIMO) channel sounder realization by use of software-defined radio (SDR) hardware (NI USRP-2954, X310 series with UBX 160 daughterboard). Essential basic functionalities are the synchronous switching of the antenna elements at both link ends and an integrated automatic gain control (AGC) at the receiver. To meet the high timing requirements in the switched MIMO setup, an FPGA-based AGC is introduced. The detector of the AGC is based on a sample-by-sample calculation of the average and maximum of the I/Q samples within a sliding window. The used SDR hardware allows a minimum AGC update interval of approx. 14 [my]s and a timing accuracy of the antenna switching of 5 ns. Our setup demonstrates the applicability of state-of-the-art SDRs as a sounding system for continuous acquisition of the time-variant, directional mobile radio channel.
https://doi.org/10.1109/I2MTC50364.2021.9460077
Characterization of urban radio channels and base station antenna correlation in the 3.75 GHz band. - In: 2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring), (2021), insges. 5 S.
Single side mMIMO channel measurements over 100 MHz bandwidth at 3.75 GHz were performed in two German cities. In dense urban as well as urban/suburban environments, a total track length of about 20 km has been measured. Multipath parameters by means of the high-resolution parameter estimator RIMAX are estimated and subsequently used to derive the statistics of large scale parameters and to allow a comparison to the statistics from standard channel model (3GPP, WINNER). While most of the parameters match quite well, for the angular spread at the base station (BS) partly larger deviations are observed. The correlation properties between the 32 dual polarized antenna patches of the BS antenna are investigated with respect to the antenna patch separation as well as to the distance between the BS and user equipment (UE).
https://doi.org/10.1109/VTC2021-Spring51267.2021.9448718
Statistics of vehicular detectability for cooperative passive coherent location at urban crossroad. - In: Radar on the move, (2021), insges. 6 S.
The statistical study of target detectability is crucial in radar system design. In this regard, signal-to-noise ratio (SNR) of the received signal at the radars receiver is a key parameter and therefore every influence on SNR should be taken into account. One of the main influences is the fluctuation of the target scattering/reflectivity to the incident electromagnetic wave. Consequently, the target fluctuation models and their accuracy become important. For monostatic radar system, various models can be found in the literature. In contrast, this paper studies a case of vehicular sensing scenario with multistatic configuration for an urban crossroad and proposes a modelling method of the target fluctuation by taking into account the target information, such as size, shape and composed materials, and the wave information, such as polarizations and aspect angles. Furthermore, the derived target fluctuation models are then applied directly to the formulation of the probability of detection for multistatic radar system. These probabilities of detection are also compared to that of monostatic radar system.
https://doi.org/10.1109/RadarConf2147009.2021.9454971
Estimation bounds of beat signal in the R-mode localization system. - In: IEEE access, ISSN 2169-3536, Bd. 9 (2021), S. 69278-69286
The R-Mode system is a terrestrial navigation system currently under development, which exploits existing means of medium frequency radio transmission. The positioning and timing performance depends on the estimation of the signals' phase offset, from which the ranging information is derived. For an analogous problem such as the single-tone phase estimation, the Cramér-Rao bound (CRB) describes the minimal achievable performance in the mean squared error sense. For R-Mode, the problem involves the estimation of the phase offset for a beat signal, which can be described as the difference of phase estimation for the two aiding carriers next to the signal. This estimates are not statistically independent for finite observation, as we show in this paper. The effect becomes stronger for short observation times, which are important for a near real time application. In this contribution, we are interested in phase offset estimation for the signal models relevant to R-Mode: a beat signal and a beat signal combined with an MSK signal. A closed-form lower CRB is proposed for the aforementioned signal models phase estimation, as well as a generalization of the bound for the phase-difference estimation. Based on this derivation, optimized bit sequences are shown to improve performance of the estimates. The validity of the proposal is verified based on a simulation setup. Measurements acquired during a measurement campaign serve to further justify the usefulness of the bound. Some possible applications of such a bound are R-Mode coverage prediction and the associated phase estimators' performance.
https://doi.org/10.1109/ACCESS.2021.3076845
UHF RFID tag performance measurements for SLCs applications using DIY-positioners. - In: Focus on linking antennas and propagation with the automotive and 5G industries, (2021), insges. 5 S.
With this paper, we present cost-effective techniques to characterize UHF RFID performance with regards to small load carriers (SLC). A self-developed turntable-positioner is used to measure the antenna pattern of tags attached to empty SLCs, as well as SLCs filled with scrap metal. With the tag-positioner we presented in a recent publication, read range degradation of various tags near dissipative and conductive electro static discharge (ESD) protective material was investigated. We also measured the sensitivity of around 80 different tags in front of an SLC made of ESD protective material and compared their performance to operation in free-space propagation. To conduct the measurements themselves, we use commercial off-the-shelf readers like the R420 from Impinj, which we control via low level reader protocol (LLRP) commands, implemented in Python.
https://doi.org/10.23919/EuCAP51087.2021.9411100
On the modelling of the NLOS first multi-path component in stochastic spatial channel models. - In: Focus on linking antennas and propagation with the automotive and 5G industries, (2021), insges. 5 S.
Positioning and localization is one of the key features in the 5G and beyond wireless networks. Since accuracy strongly depends on the channel conditions, channel models are of special importance for the testing and development of such applications. While several localization methods are based on the time of arrival (ToA) and time-difference of arrival (TDoA), stochastic spatial channel models (SCMs) as the 3GPP don't consider absolute values on the delays of the non-line of sight (NLOS) multi-path components (MPCs), making these models not appropriate for these applications. Therefore, we investigate the time and angular characteristics of the first multi-path component (FMPC) using multi-band ray tracing (RT) simulations in order to extend stochastic SCMs to support localization applications in NLOS.
https://doi.org/10.23919/EuCAP51087.2021.9411142
MIMO-TDL model parameter estimation from V2I channel sounding. - In: Focus on linking antennas and propagation with the automotive and 5G industries, (2021), insges. 5 S.
This contribution proposes modeling methods for MIMO-TDL channel models under new evaluation method, which is non-WSSUS. V2X channels cannot be assumed to follow the WSSUS assumption due to high inherent mobility. It can be extended to non-WSSUS by employing an ON/OFF process (persistence process). An algorithm to select taps and estimate their parameters from measured data is illustrated. Meanwhile, the slow and fast fading is separated from received signal to assess the fading distribution of taps. The analysis investigates correlation coefficient among taps persistence process, as well as, among taps amplitude. Additionally, an approach is discussed to develop a time varying MIMO-TDL model, whose parameters are varying over time.
https://doi.org/10.23919/EuCAP51087.2021.9411322
Accuracy of fill level measurement by an M-sequence UWB guided wave radar. - In: Focus on linking antennas and propagation with the automotive and 5G industries, (2021), insges. 4 S.
Due to increasingly complex and automated manufacturing processes of producing companies, the demands on the control parameters of these processes are also increasing. An important parameter is the fill quantity, whose precise determination is becoming of growing importance. It is of additional interest to be able to automatically determine what filling material is currently being used to ensure that the correct material is in the container. This paper shows with which accuracy an M-sequence UWB guided wave radar can determine levels in metallic and non-metallic containers and which possibilities exist to determine the filling material. First, the principle of level measurement using guided wave radar is explained and the measurement setup is described. Afterward, the measurement results are shown and discussed. The measurements show that the level can be measured with an accuracy of less than 0.5 mm. In addition, level fluctuations can be detected with an accuracy of 3 µm.
https://doi.org/10.23919/EuCAP51087.2021.9411205
Modeling of transitions in received power for an urban V2I scenario. - In: Focus on linking antennas and propagation with the automotive and 5G industries, (2021), insges. 5 S.
In this contribution, we investigate how changes in received power for a vehicle to infrastructure (V2I) communication scenario in an urban environment can be modeled. Significant changes are not only observed for line of sight (LoS) to none line of sight (NLoS) transitions but also when the mobile station travels from a narrow street onto a crossroad and other maneuvers, even with no LoS being present. To model these transitions, in terms of received power, we propose a variant of an arctangent function. We fit the model to different exemplary transitions, which were found in channel sounding data collected in a V2I measurement campaign. We discuss the results in terms of quality of fit and the estimated parameters.
https://doi.org/10.23919/EuCAP51087.2021.9411370
Cost-effective measurement methods to investigate RF leakages in UHF RFID e-Kanban racks. - In: Focus on linking antennas and propagation with the automotive and 5G industries, (2021), insges. 4 S.
In this paper, we present cost-effective techniques to assess shielding performance of RFID Kanban racks equipped with UHF RFID readers. This includes a self-developed positioner, made from roof battens and stepper motors, which positions a tag in a vertical area around each side of the rack to sense the radio frequency (RF) distribution emitted from the reader. For the measurements on the shelves, we sticked 30 tags on a foam board in a 20 cm grid to detect leakages on the horizontal planes. The overall material cost is less than 50 € and we made the documentation and control software publicly available.
https://doi.org/10.23919/EuCAP51087.2021.9411416
Characterization of slow and fast fading in V2I channels for smart cities. - In: Focus on linking antennas and propagation with the automotive and 5G industries, (2021), insges. 5 S.
A vehicle to X (V2X) propagation channel corresponds to a wideband channel that means a receiver (Rx) able to resolve multipath components. In contrast to a narrow band channel, multipath components are indistinguishable at the receiver and seen as a single composite signal, thus fading approximation has been assumed as the Rayleigh fading. It is interesting to see how the fading is characterized in V2X applications because the channel corresponds to the wideband and it can not be assumed to follow wide sense stationary uncorrelated scattering (WSSUS) assumption due to inherent mobility. The aim of this paper is to characterize and study slow fading and fast fading variations of each tap, which is selected from measurement data. This investigation pertains to three various scenarios, which are omnidirectional antenna, two antennas faced directly to each other and two antennas faced away from each other. In each scenario, LOS and two different NLOS categories are studied.
https://doi.org/10.23919/EuCAP51087.2021.9411001
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
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
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
Characterization of GPS disciplined oscillators using a laboratory GNSS simulation testbed. - In: IEEE IFCS-ISAF 2020, (2020), insges. 4 S.
This paper introduces a testbed to characterize the performance of GPS disciplined oscillators using a GNSS signal simulator and a measurement system based on software-defined radios and digital signal processing that allows to examine the stability of up to four devices with sub-nanosecond precision, time-coherently for 1 PPS and 10 MHz signals, in a controllable laboratory environment with reproducible and adjustable GNSS signal settings over a long-term observation period. To demonstrate the effectiveness of this method, four devices of one specific low-cost GPSDO type available to the authors are characterized and compared in terms of their positional accuracy and their time and frequency stability in steady state and during stabilization.
https://doi.org/10.1109/IFCS-ISAF41089.2020.9234932
Stochastic modeling of short and long term clock skew. - In: IEEE IFCS-ISAF 2020, (2020), insges. 4 S.
Traditional black box clock skew models are either the power-law noise model or a more recent approach based on auto-regressive (AR) filters. Unfortunately, neither algorithm can accurately model short and long term skew due to limited degrees of freedom or stability constraints. We propose a novel model that employs the current AR algorithm recursively with appropriate pre- and post-processing to achieve numeric stability and accurate reproduction of short and long term effects. The model coefficients are derived from a measured skew signal, with the model output matching an exemplary original signal closely in terms of Allan variance and time-domain behavior.
https://doi.org/10.1109/IFCS-ISAF41089.2020.9234818
Characterizing GPS disciplined oscillators for distributed vehicle-to-X measurement applications. - In: IEEE IFCS-ISAF 2020, (2020), insges. 4 S.
In this paper, we analyze the reference signal stability of 1 PPS and 10 MHz signals provided by a low-cost GPS disciplined oscillator under application specific conditions using a comparable light-weight measurement system based on software defined radio and digital signal processing. In mobile measurement scenarios, GPS signal impairments are inevitable, due to obstacles such as buildings, street canyons, bridges, and tunnels. Therefore, we preliminarily characterize four GPSDOs under test in a stationary setup using controlled GPS reception loss to drive them into alternating operation modes, namely free-run, disciplined and holdover mode. Further, we conducted a more than 100 km real-world diversified test drive to characterize the performance of the particular GPSDO as realistically as possible for the intended use in mobile V2X measurements.
https://doi.org/10.1109/IFCS-ISAF41089.2020.9234915
Acoustic process monitoring in laser beam welding. - In: 11th CIRP Conference on Photonic Technologies [LANE 2020], (2020), S. 763-768
Structure-borne acoustic emission (AE) measurement shows major advantages regarding quality assurance and process control in industrial applications. In this paper, laser beam welding of steel and aluminum was carried out under varying process parameters (welding speed, focal position) in order to provide data by means of structure-borne AE and simultaneously high-speed video recordings. The analysis is based on conventionally (e.g. filtering, autocorrelation, spectrograms) as well as machine learning methods (convolutional neural nets) and showed promising results with respect to the use of structure-borne AE for process monitoring using the example of spatter formation.
https://doi.org/10.1016/j.procir.2020.09.139
OFDM waveform for distributed radar sensing in automotive scenarios. - In: International journal of microwave and wireless technologies, ISSN 1759-0795, Bd. 12 (2020), 8, S. 716-722
https://doi.org/10.1017/S1759078720000859
eadf: representation of far-field antenna responses in Python. - In: SoftwareX, ISSN 2352-7110, Bd. 12 (2020), 100583, S. 1-6
https://doi.org/10.1016/j.softx.2020.100583
Measurement campaign with synchronized distributed receivers and mobile emitter at 3.75 GHz in urban scenarios. - In: 2020 IEEE 91st Vehicular Technology Conference (VTC Spring), (2020), insges. 5 S.
https://doi.org/10.1109/VTC2020-Spring48590.2020.9128562
Performance of OFDMA resource scheduling in joint mobile radio and radar networks. - In: 14th European Conference on Antennas and Propagation, (2020), insges. 5 S.
https://doi.org/10.23919/EuCAP48036.2020.9135864
Multi-band characterization of propagation in industry scenarios. - In: 14th European Conference on Antennas and Propagation, (2020), insges. 5 S.
https://doi.org/10.23919/EuCAP48036.2020.9135630
Characterization of the propagation channel in conference room scenario at 190 GHz. - In: 14th European Conference on Antennas and Propagation, (2020), insges. 5 S.
https://doi.org/10.23919/EuCAP48036.2020.9135404
3D calibration of an over-the-air testbed for GNSS CRPA antenna testing. - In: 14th European Conference on Antennas and Propagation, (2020), insges. 5 S.
https://doi.org/10.23919/EuCAP48036.2020.9135937
Redesigned waveforms in the maritime medium frequency bands. - In: 2020 IEEE/ION Position, Location and Navigation Symposium (PLANS), (2020), S. 827-831
https://doi.org/10.1109/PLANS46316.2020.9110174
Clutter removal of near-field UWB SAR imaging for pipeline penetrating radar. - In: IEEE journal of selected topics in applied earth observations and remote sensing, ISSN 2151-1535, Bd. 13 (2020), S. 1527-1539
https://doi.org/10.1109/JSTARS.2020.2983891
Data security and trading framework for smart grids in neighborhood area networks. - In: Sensors, ISSN 1424-8220, Bd. 20 (2020), 5, 1337, insges. 25 S.
https://doi.org/10.3390/s20051337
UHF RFID tag response measurements using a do-it-yourself platform and components off-the-shelf. - In: IEEE journal of radio frequency identification, ISSN 2469-7281, Bd. 4 (2020), 1, S. 65-72
https://doi.org/10.1109/JRFID.2020.2965006
Ein portabler, vielfältig einsetzbarer 3D-Positionierer für Synthetik-Apertur-Ultraschallmessungen in der ZfP. - In: DACH-Jahrestagung 2019, (2019), insges. 2 S.
Paper P41
A Chinese remainder theorem based perfect secret sharing scheme with enhanced secret range values using tensor based operations. - In: 2019 13th International Conference on Signal Processing and Communication Systems (ICSPCS), (2019), insges. 6 S.
https://doi.org/10.1109/ICSPCS47537.2019.9008712
Utilization of the V2X radio channels temporal stationarity for communication and radar sensing. - In: 2019 International Symposium on Antennas and Propagation, (2019), insges. 4 S.
https://ieeexplore.ieee.org/document/8963511
Hybrid ray tracing method for millimeter wave propagation simulation in large indoor scenarios. - In: WSA 2019, (2019), S. 99-104
https://ieeexplore.ieee.org/document/8727201
3D reconstruction of handheld data by SAFT and the influence of measurement inaccuracies. - In: 2019 IEEE International Ultrasonics Symposium (IUS), (2019), S. 2095-2098
https://doi.org/10.1109/ULTSYM.2019.8926018
SAFT processing for manually acquired ultrasonic measurement data with 3D smartInspect. - In: Insight, ISSN 0007-1137, Bd. 61 (2019), 11, S. 663-669
https://doi.org/10.1784/insi.2019.61.11.663
Defect detection from compressed 3-D ultrasonic frequency measurements. - In: 27th EUSIPCO 2019 - European Signal Processing Conference, (2019), insges. 5 S.
https://doi.org/10.23919/EUSIPCO.2019.8903133
Joint high-resolution delay-doppler estimation for bi-static radar measurements. - In: 2019 16th European Radar Conference, (2019), S. 145-148
https://ieeexplore.ieee.org/document/8904605
OFDM waveform for distributed radar sensing in automotive scenarios. - In: 2019 16th European Radar Conference, (2019), S. 225-228
https://ieeexplore.ieee.org/document/8904754
Multi-band vehicle to vehicle channel measurements from 6 GHz to 60 GHz at "T" intersection. - In: 2019 IEEE 2nd Connected and Automated Vehicles Symposium (CAVS), (2019), insges. 5 S.
https://doi.org/10.1109/CAVS.2019.8887794
Multi-band propagation and radio channel characterization in street canyon scenarios for 5G and beyond. - In: IEEE access, ISSN 2169-3536, Bd. 7 (2019), S. 160385-160396
https://doi.org/10.1109/ACCESS.2019.2948869
Influence of spatial-wideband effects in evaluation of mm-wave communications. - In: IET microwaves, antennas & propagation, ISSN 1751-8733, Bd. 13 (2019), 13, S. 2200-2206
https://doi.org/10.1049/iet-map.2018.6160
Multi-band double-directional 5G street canyon measurements in Germany. - In: 2019 European Conference on Networks and Communications (EuCNC), (2019), S. 123-127
https://doi.org/10.1109/EuCNC.2019.8801951
Wideband air-ground channel model for a regional airport environment. - In: IEEE transactions on vehicular technology, ISSN 1939-9359, Bd. 68 (2019), 7, S. 6243-6256
https://doi.org/10.1109/TVT.2019.2914337
Experimental and analytical characterization of time-variant V2V channels in a highway scenario. - In: 2019 13th European Conference on Antennas and Propagation (EuCAP), (2019), insges. 5 S.
https://ieeexplore.ieee.org/document/8739792
Statistical analysis and modeling of vehicular radar cross section. - In: 2019 13th European Conference on Antennas and Propagation (EuCAP), (2019), insges. 5 S.
https://ieeexplore.ieee.org/document/8740243
Investigation on stationarity of V2V channels in a highway scenario. - In: 2019 13th European Conference on Antennas and Propagation (EuCAP), (2019), insges. 5 S.
https://ieeexplore.ieee.org/document/8739916
Multi-band indoor propagation characterization by measurements from 6 to 60 GHz. - In: 2019 13th European Conference on Antennas and Propagation (EuCAP), (2019), insges. 5 S.
https://ieeexplore.ieee.org/document/8739860
Polarization in spatial channel models at mm-waves: a correlation based approach. - In: 2019 13th European Conference on Antennas and Propagation (EuCAP), (2019), insges. 5 S.
https://ieeexplore.ieee.org/document/8739948
Bi-static delay-Doppler emulation of cooperative passive vehicle-to-X radar. - In: 2019 13th European Conference on Antennas and Propagation (EuCAP), (2019), insges. 5 S.
https://ieeexplore.ieee.org/document/8739479
A versatile, automated, cost-effective testing platform for hands-on UHF RFID measurements. - In: 2019 IEEE International Conference on RFID (RFID), (2019), insges. 7 S.
https://doi.org/10.1109/RFID.2019.8719272
Tensor-based time-delay estimation for second and third generation global positioning system. - In: Digital signal processing, ISSN 1051-2004, Bd. 92 (2019), S. 1-19
https://doi.org/10.1016/j.dsp.2019.04.003
Standardized testing conditions for satellite communications on-the-move (SOTM) terminals. - In: International journal of satellite communications and networking, ISSN 1542-0981, Bd. 37 (2019), 3, S. 163-182
https://doi.org/10.1002/sat.1272
M-estimator based Chinese Remainder Theorem with few remainders using a Kroenecker product based mapping vector. - In: Digital signal processing, ISSN 1051-2004, Bd. 87 (2019), S. 60-74
https://doi.org/10.1016/j.dsp.2019.01.009
Sub-band versus space-delay precoding for wideband mmWave channels. - In: IEEE wireless communications letters, ISSN 2162-2345, Bd. 8 (2019), 1, S. 193-196
https://doi.org/10.1109/LWC.2018.2866250
Automotive antenna roof for cooperative connected driving. - In: IEEE access, ISSN 2169-3536, Bd. 7 (2019), S. 20083-20090
https://doi.org/10.1109/ACCESS.2019.2897219
Low-complexity and high-accuracy semi-blind joint channel and symbol estimation for massive MIMO-OFDM. - In: Circuits, systems and signal processing, ISSN 1531-5878, Bd. 38 (2019), 3, S. 1114-1136
https://doi.org/10.1007/s00034-018-0898-1
Cooperative passive coherent location: a promising 5G service to support road safety. - In: IEEE communications magazine, ISSN 1558-1896, Bd. 57 (2019), 9, S. 86-92
https://doi.org/10.1109/MCOM.001.1800242
Vergleich und Anpassung von 3D-SAFT-Implementierungen im Zeit- und Frequenzbereich für die schnelle Grobblechprüfung. - In: DGZfP-Jahrestagung 2018, (2018), insges. 2 S.
Tracking based multipath clustering in vehicle-to-infrastructure channels. - In: 2018 IEEE 29th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), ISBN 978-1-5386-6009-6, (2018), insges. 5 S.
https://doi.org/10.1109/PIMRC.2018.8580979
Multi-band characterization of path-loss, delay, and angular spread in V2V links. - In: 2018 IEEE 29th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), ISBN 978-1-5386-6009-6, (2018), S. 85-90
https://doi.org/10.1109/PIMRC.2018.8580797
Progressive online 3-D SAFT processing by matrix structure exploitation. - In: 2018 IEEE International Ultrasonics Symposium (IUS), (2018), insges. 4 S.
https://doi.org/10.1109/ULTSYM.2018.8579696
A fast and stable time locked loop for network time synchronization with parallel FLL and PLL. - In: ISPCS 2018, (2018), insges. 6 S.
https://doi.org/10.1109/ISPCS.2018.8543066
Comparison of software-defined radios for performance evaluation of high precision clocks. - In: ISPCS 2018, (2018), insges. 6 S.
https://doi.org/10.1109/ISPCS.2018.8543073
Sensing matrix sensitivity to random Gaussian perturbations in compressed sensing. - In: EUSIPCO 2018, ISBN 978-90-827970-1-5, (2018), S. 583-587
https://doi.org/10.23919/EUSIPCO.2018.8553575
Defect detection from 3D ultrasonic measurements using matrix-free sparse recovery algorithms. - In: EUSIPCO 2018, ISBN 978-90-827970-1-5, (2018), S. 1700-1704
https://doi.org/10.23919/EUSIPCO.2018.8553074
Conformal automotive roof-top antenna cavity with increased coverage to vulnerable road users. - In: IEEE antennas and wireless propagation letters, ISSN 1548-5757, Bd. 17 (2018), 12, S. 2399-2403
https://doi.org/10.1109/LAWP.2018.2876628
Modeling of intra-cluster multipaths for 60 GHz fading channels. - In: 12th European Conference on Antennas and Propagation (EuCAP 2018), ISBN 978-1-78561-816-1, (2018), insges. 5 S.
https://doi.org/10.1049/cp.2018.0873
On modeling OTA channel emulation systems. - In: 12th European Conference on Antennas and Propagation (EuCAP 2018), ISBN 978-1-78561-816-1, (2018), insges. 5 S.
https://doi.org/10.1049/cp.2018.0862
Influence of system aspects in propagation based evaluation of beam-forming at mm-waves. - In: 12th European Conference on Antennas and Propagation (EuCAP 2018), ISBN 978-1-78561-816-1, (2018), insges. 5 S.
https://doi.org/10.1049/cp.2018.0763
Multi-band spatio-temporal characterization of a V2V environment under blockage. - In: 12th European Conference on Antennas and Propagation (EuCAP 2018), ISBN 978-1-78561-816-1, (2018), insges. 5 S.
https://doi.org/10.1049/cp.2018.0725
Investigation of V2I channel transitions in urban environment. - In: 12th European Conference on Antennas and Propagation (EuCAP 2018), ISBN 978-1-78561-816-1, (2018), insges. 5 S.
https://doi.org/10.1049/cp.2018.0723
Estimation and characterization of multipath clusters in urban scenarios. - In: 12th European Conference on Antennas and Propagation (EuCAP 2018), ISBN 978-1-78561-816-1, (2018), insges. 5 S.
https://doi.org/10.1049/cp.2018.0390
Contribution to drone detection by exploiting parameter estimation for a prototype mm-wave radar system. - In: WSA 2018, (2018), insges. 8 S.
https://ieeexplore.ieee.org/document/8385469
Compressive spatial channel sounding. - In: 12th European Conference on Antennas and Propagation (EuCAP 2018), ISBN 978-1-78561-816-1, (2018), insges. 5 S.
http://dx.doi.org/10.1049/cp.2018.0472
Combining matrix design for 2D DoA estimation with compressive antenna arrays. - In: WSA 2018, (2018), insges. 8 S.
https://ieeexplore.ieee.org/document/8385488
Analysis and design of broadband simultaneous wireless information and power transfer (SWIPT) system considering rectifier effect. - In: Energies, ISSN 1996-1073, Bd. 11 (2018), 9, 2387, S. 1-18
https://doi.org/10.3390/en11092387
Grid-free Direction-of-Arrival estimation with compressed sensing and arbitrary antenna arrays. - In: 2018 IEEE International Conference on Acoustics, Speech, and Signal Processing, ISBN 978-1-5386-4658-8, (2018), S. 3251-3255
https://doi.org/10.1109/ICASSP.2018.8462501
Reflector localization for geometrical modeling the air-ground channel. - In: IEEE transactions on vehicular technology, ISSN 1939-9359, Bd. 67 (2018), 9, S. 7994-8008
https://doi.org/10.1109/TVT.2018.2849686
Measuring ETSI ITS-G5 communications latencies with commercial off-the-shelf Wi-Fi hardware. - In: 2018 IEEE MTT-S International Conference on Microwaves for Intelligent Mobility (ICMIM), ISBN 978-1-5386-1725-0, (2018), insges. 4 S.
https://doi.org/10.1109/ICMIM.2018.8443355
Sparsity order estimation from a single compressed observation vector. - In: IEEE transactions on signal processing, ISSN 1941-0476, Bd. 66 (2018), 15, S. 3958-3971
https://doi.org/10.1109/TSP.2018.2841867
High-resolution parameter estimation for chirp-sequence radar considering hardware impairments. - In: Riding the green waves, (2018), S. 355-358
https://doi.org/10.23919/GEMIC.2018.8335103
High-precision measurement of sine and pulse reference signals using software-defined radio. - In: IEEE transactions on instrumentation and measurement, ISSN 0018-9456, Bd. 67 (2018), 5, S. 1132-1141
https://doi.org/10.1109/TIM.2018.2794940
Evaluation of array antenna systems for global navigation satellite system applications using wave-field synthesis in an over-the-air laboratory. - In: IET microwaves, antennas & propagation, ISSN 1751-8733, Bd. 12 (2018), 4, S. 554-560
https://doi.org/10.1049/iet-map.2017.0580
Influence of system aspects on fading at mm-waves. - In: IET microwaves, antennas & propagation, ISSN 1751-8733, Bd. 12 (2018), 4, S. 516-524
https://doi.org/10.1049/iet-map.2017.0601
Multiband TDOA estimation from sub-Nyquist samples with distributed wideband sensing nodes. - In: 2017 IEEE Global Conference on Signal and Information Processing, ISBN 978-1-5090-5990-4, (2017), S. 96-100
https://doi.org/10.1109/GlobalSIP.2017.8308611
Time-delay estimation via CPD-GEVD applied to tensor-based GNSS arrays with errors. - In: 2017 IEEE 7th International Workshop on Computational Advances in Multi-Sensor Adaptive Processing (CAMSAP), (2017), insges. 5 S.
https://doi.org/10.1109/CAMSAP.2017.8313098
Broadband beamforming via frequency invariance transformation and PARAFAC decomposition. - In: 2017 IEEE 7th International Workshop on Computational Advances in Multi-Sensor Adaptive Processing (CAMSAP), (2017), insges. 5 S.
https://doi.org/10.1109/CAMSAP.2017.8313096
Antenna array based framework with multipath mitigation for signal emitter detection and localization. - In: 2017, 11th International Conference on Signal Processing and Communication Systems (ICSPCS), ISBN 978-1-5386-2887-4, (2017), insges. 5 S.
https://doi.org/10.1109/ICSPCS.2017.8270462
Polarization optimization of compact antenna arrays for direction of arrival estimation. - In: 2017 14th European Radar Conference, ISBN 978-2-87487-049-1, (2017), S. 485-488
https://doi.org/10.23919/EURAD.2017.8249253
Interference mitigation in mm-wave backhaul networks with limited channel-state information. - In: 2017 IEEE International Conference on Microwaves, Antennas, Communications and Electronic Systems (COMCAS), ISBN 978-1-5386-3169-0, (2017), insges. 5 S.
https://doi.org/10.1109/COMCAS.2017.8244804
3D-SAFT auf vorverarbeiteten Ultraschallsignalen - schneller messen bei verbesserter Auflösung. - In: ZfP in Forschung, Entwicklung und Anwendung, (2017), insges. 2 S.
Polarization optimization of compact antenna arrays for direction of arrival estimation. - In: 2017 47th European Microwave Conference, ISBN 978-2-87487-047-7, (2017), S. 1333-1336
https://doi.org/10.23919/EuMC.2017.8231098
Implementation issues of 3D SAFT in time and frequency domain for the fast inspection of heavy plates. - In: 2017 IEEE International Ultrasonics Symposium (IUS), ISBN 978-1-5386-3383-0, (2017), insges. 4 S.
https://doi.org/10.1109/ULTSYM.2017.8092833
Suitability of compact antenna arrays for direction-of-arrival estimation. - In: IEEE transactions on antennas and propagation, ISSN 1558-2221, Bd. 65 (2017), 12, S. 7244-7256
https://doi.org/10.1109/TAP.2017.2757968
Implementation of sparse signal recovery on FPGA for ultrasonic NDT. - In: 2017 IEEE International Ultrasonics Symposium (IUS), ISBN 978-1-5386-3383-0, (2017), insges. 1 S.
https://doi.org/10.1109/ULTSYM.2017.8092308
Differential SART for sub-Nyquist tomographic reconstruction in presence of misalignments. - In: EUSIPCO 2017, ISBN 978-0-9928626-7-1, (2017), S. 2354-2358
https://doi.org/10.23919/EUSIPCO.2017.8081631
Tensor-based sparsity order estimation for big data applications. - In: EUSIPCO 2017, ISBN 978-0-9928626-7-1, (2017), S. 648-652
https://doi.org/10.23919/EUSIPCO.2017.8081287
On the polarization effects of decoupling and matching networks on compact single-polarized antenna arrays for direction finding. - In: 2017 IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC), ISBN 978-1-5090-4454-2, (2017), S. 256-259
https://doi.org/10.1109/APWC.2017.8062295
UWB M-sequence based radar technology for localization of first responders. - In: 2017 18th International Radar Symposium (IRS), ISBN 978-3-7369-9343-3, (2017), insges. 9 S.
https://doi.org/10.23919/IRS.2017.8008218
Offline mode for corporate mobile client security architecture. - In: Mobile networks and applications, ISSN 1572-8153, Bd. 22 (2017), 4, S. 743-759
https://doi.org/10.1007/s11036-017-0839-4
Using software defined radios for baseband phase measurement and frequency standard calibration. - In: I2MTC - 2017 IEEE International Instrumentation and Measurement Technology Conference, ISBN 978-1-5090-3596-0, (2017), insges. 5 S.
https://doi.org/10.1109/I2MTC.2017.7969657
Attaining low uncertainties in measurements with RF signal generators and analyzers. - In: I2MTC - 2017 IEEE International Instrumentation and Measurement Technology Conference, ISBN 978-1-5090-3596-0, (2017), insges. 6 S.
https://doi.org/10.1109/I2MTC.2017.7969907
Radiofrequency energy harvesting system based on a rectenna array in urban environments. - In: International Conference on Signals and Systems, ISBN 978-1-5090-6748-0, (2017), S. 151-157
https://doi.org/10.1109/ICSIGSYS.2017.7967031
On the SNR variability in noisy compressed sensing. - In: IEEE signal processing letters, ISSN 1558-2361, Bd. 24 (2017), 8, S. 1148-1152
https://doi.org/10.1109/LSP.2017.2689243
Sparse signal recovery for ultrasonic detection and reconstruction of shadowed flaws. - In: 2017 IEEE International Conference on Acoustics, Speech, and Signal Processing, ISBN 978-1-5090-4117-6, (2017), S. 816-820
https://doi.org/10.1109/ICASSP.2017.7952269
New challenges in over-the-air testing. - In: 2017 11th European Conference on Antennas and Propagation (EUCAP), ISBN 978-88-907018-7-0, (2017), S. 3676-3678
https://doi.org/10.23919/EuCAP.2017.7928837
Evaluation of array antenna systems for GNSS applications using wave-field synthesis in an OTA laboratory. - In: 2017 11th European Conference on Antennas and Propagation (EUCAP), ISBN 978-88-907018-7-0, (2017), S. 3370-3374
https://doi.org/10.23919/EuCAP.2017.7928727
Modeling the air-ground multipath channel. - In: 2017 11th European Conference on Antennas and Propagation (EUCAP), ISBN 978-88-907018-7-0, (2017), S. 1434-1438
https://doi.org/10.23919/EuCAP.2017.7928222
Antenna array configurations for terrestrial backhaul links at Ka-band frequencies. - In: 2017 11th European Conference on Antennas and Propagation (EUCAP), ISBN 978-88-907018-7-0, (2017), S. 431-435
https://doi.org/10.23919/EuCAP.2017.7928110
High resolution time-delay estimation via direction of arrival estimation and Khatri-Rao factorization for multipath mitigation. - In: WSA 2017, ISBN 978-3-8007-4394-0, (2017), insges. 8 S.
KASYMOSA - Ka-Bandsysteme für die mobile Satellitenkommunikation : Schlussbericht. - Ilmenau : Fraunhofer-Institut für Integrierte Schaltungen IIS. - 1 Online-Ressource (111 Seiten, 5,15 MB)Förderkennzeichen BMWi 50 YB 1319 - 50 YB 1320 - 50 YB 1321. - Verbund-Nummer 01143745
https://edocs.tib.eu/files/e01fb17/886552214.pdf
Model order selection and eigen similarity based framework for detection and identification of network attacks. - In: Journal of network and computer applications, ISSN 1095-8592, Bd. 90 (2017), S. 26-41
https://doi.org/10.1016/j.jnca.2017.04.012
Design and analysis of compressive antenna arrays for direction of arrival estimation. - In: Signal processing, Bd. 138 (2017), S. 35-47
https://doi.org/10.1016/j.sigpro.2017.03.013
Performance analysis of multi-dimensional ESPRIT-type algorithms for arbitrary and strictly non-circular sources with spatial smoothing. - In: IEEE transactions on signal processing, ISSN 1941-0476, Bd. 65 (2017), 9, S. 2262-2276
https://doi.org/10.1109/TSP.2017.2652388
Tensor-based methods for blind spatial signature estimation in multidimensional sensor arrays. - In: International journal of antennas and propagation, ISSN 1687-5877, Bd. 2017 (2017), Article ID 1615962, insges. 11 S.
https://doi.org/10.1155/2017/1615962
Low complexity performance assessment of a sensor array via unscented transformation. - In: Digital signal processing, ISSN 1051-2004, Bd. 63 (2017), S. 190-198
http://dx.doi.org/10.1016/j.dsp.2017.01.007
ESPRIT-Hilbert-based audio tampering detection with SVM classifier for forensic analysis via electrical network frequency. - In: IEEE transactions on information forensics and security, ISSN 1556-6021, Bd. 12 (2017), 4, S. 853-864
https://doi.org/10.1109/TIFS.2016.2636095
Tensor-based methods for blind spatial signature estimation under arbitrary and unknown source covariance structure. - In: Digital signal processing, ISSN 1051-2004, Bd. 62 (2017), S. 197-210
http://dx.doi.org/10.1016/j.dsp.2016.12.003
Multi-hop cooperative XIXO transmission scheme for delay tolerant wireless sensor networks. - In: WSA 2016, (2016), S. 308-312
http://ieeexplore.ieee.org/document/7499143/
On the earth mover's distance as a performance metric for sparse support recovery. - In: 2016 IEEE Global Conference on Signal and Information Processing, ISBN 978-1-5090-4545-7, (2016), S. 1368-1372
https://doi.org/10.1109/GlobalSIP.2016.7906065
Procedures for integrating, testing and operating advanced microsatellites. - In: IFAC-PapersOnLine, ISSN 2405-8963, Bd. 49 (2016), 30, S. 75-79
http://dx.doi.org/10.1016/j.ifacol.2016.11.130
First step towards a smart grid communication architecture for the Brazilian Federal District. - In: IFAC-PapersOnLine, ISSN 2405-8963, Bd. 49 (2016), 30, S. 251-256
http://dx.doi.org/10.1016/j.ifacol.2016.11.120
Low complexity blind separation technique to solve the permutation ambiguity of convolutive speech mixtures. - In: 2016, 10th International Conference on Signal Processing and Communication Systems, (ICSPCS), ISBN 978-1-5090-0941-1, (2016), insges. 10 S.
https://doi.org/10.1109/ICSPCS.2016.7843325
Applying base value of fundamental frequency via the multivariate Kernel-Density in Forensic Speaker Comparison. - In: 2016, 10th International Conference on Signal Processing and Communication Systems, (ICSPCS), ISBN 978-1-5090-0941-1, (2016), insges. 8 S.
https://doi.org/10.1109/ICSPCS.2016.7843307
Audio authentication using the kurtosis of ESPRIT based ENF estimates. - In: 2016, 10th International Conference on Signal Processing and Communication Systems, (ICSPCS), ISBN 978-1-5090-0941-1, (2016), insges. 6 S.
https://doi.org/10.1109/ICSPCS.2016.7843308
Linear baseband precoding strategies for millimeter wave MIMO multi-X channels. - In: IEEE PIMRC 2016, ISBN 978-1-5090-3254-9, (2016), insges. 7 S.
https://doi.org/10.1109/PIMRC.2016.7794689
Block diagonalization for interference mitigation in Ka-band backhaul networks. - In: IEEE PIMRC 2016, ISBN 978-1-5090-3254-9, (2016), insges. 6 S.
http://dx.doi.org/10.1109/PIMRC.2016.7794679
On stochastically emulating continuous scattering structures by discrete sources for OTA testing of DuT with highly directive antennas. - In: IEEE PIMRC 2016, ISBN 978-1-5090-3254-9, (2016), insges. 6 S.
http://dx.doi.org/10.1109/PIMRC.2016.7794557
Measurement matrix design for compressed sensing based time delay estimation. - In: 2016 24th European Signal Processing Conference (EUSIPCO), ISBN 978-0-9928626-5-7, (2016), S. 458-462
https://doi.org/10.1109/EUSIPCO.2016.7760290
On poisson compressed sensing and parameter estimation in sheet-of-light surface scanning. - In: 2016 24th European Signal Processing Conference (EUSIPCO), ISBN 978-0-9928626-5-7, (2016), S. 453-457
https://doi.org/10.1109/EUSIPCO.2016.7760289
An Over-The-Air wave field synthesis testbed for multi-GNSS systems - setup and verification. - In: Proceedings of the International Academic Forum AMO - SPITSE - NESEFF, ISBN 978-5-91412-313-7, (2016), S. 15-16
Motivating attendee's participation in distance learning via an automatic messaging plugin for the moodle platform. - In: The crossroads of engineering and business, ISBN 978-1-5090-1790-4, (2016), insges. 5 S.
http://dx.doi.org/10.1109/FIE.2016.7757608
Unscented transform based low complexity performance assessment for adaptive linearly constrained minimum variance filters. - In: Proceedings of the 19th International Conference on OFDM and Frequency Domain Techniques (ICOF 2016), ISBN 978-3-8007-4253-0, (2016), S. 39-44
Implementation of improved software defined radio modulation scheme and command and telemetry software interface for small satellites in 5G systems. - In: Proceedings of the 19th International Conference on OFDM and Frequency Domain Techniques (ICOF 2016), ISBN 978-3-8007-4253-0, (2016), S. 77-83
Speeding up 3D SAFT for ultrasonic NDT by sparse deconvolution. - In: 2016 IEEE International Ultrasonics Symposium (IUS), ISBN 978-1-4673-9897-8, (2016), insges. 4 S.
http://dx.doi.org/10.1109/ULTSYM.2016.7728434
Array interpolation based on multivariate adaptive regression splines. - In: 2016 IEEE Sensor Array and Multichannel Signal Processing Workshop (SAM), ISBN 978-1-5090-2103-1, (2016), insges. 5 S.
http://dx.doi.org/10.1109/SAM.2016.7569704
Spatially resolved sub-Nyquist sensing of multiband signals with arbitrary antenna arrays. - In: 2016 IEEE 17th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC), ISBN 978-1-5090-1749-2, (2016), insges. 5 S.
http://dx.doi.org/10.1109/SPAWC.2016.7536776
Deterministic Cramér-Rao bound for strictly non-circular sources and analytical analysis of the achievable gains. - In: IEEE transactions on signal processing, ISSN 1941-0476, Bd. 64 (2016), 17, S. 4417-4431
http://dx.doi.org/10.1109/TSP.2016.2566603
Antenna array optimization strategies for robust direction finding. - In: 2016 10th European Conference on Antennas and Propagation (EuCAP), ISBN 978-88-907018-6-3, (2016), insges. 5 S.
http://dx.doi.org/10.1109/EuCAP.2016.7481144
MIMO over-the-air testing for electrically large objects in non-anechoic environments. - In: 2016 10th European Conference on Antennas and Propagation (EuCAP), ISBN 978-88-907018-6-3, (2016), insges. 6 S.
http://dx.doi.org/10.1109/EuCAP.2016.7481106
Temporal wireless synchronization with compressed opportunistic signals. - In: 2016 IEEE Topical Conference on Wireless Sensors and Sensor Networks, ISBN 978-1-5090-1691-4, (2016), S. 93-96
https://doi.org/10.1109/WISNET.2016.7444331
The influence of hardware imperfections onto wave-field synthesis accuracy. - In: WSA 2015, (2015), insges. 8 S.
http://ieeexplore.ieee.org/document/7051806/
Compressed temporal synchronization with opportunistic signals. - In: Conference record of the Forty-ninth Asilomar Conference on Signals, Systems & Computers, ISBN 978-1-4673-8576-3, (2015), S. 204-208
https://doi.org/10.1109/ACSSC.2015.7421114
Adaptive measurement matrix design for compressed DoA estimation with sensor arrays. - In: Conference record of the Forty-ninth Asilomar Conference on Signals, Systems & Computers, ISBN 978-1-4673-8576-3, (2015), S. 1769-1773
http://dx.doi.org/10.1109/ACSSC.2015.7421455
Generalized sidelobe cancellers for multidimensional separable arrays. - In: 2015 IEEE 6th International Workshop on Computational Advances in Multi-Sensor Adaptive Processing (CAMSAP), ISBN 978-1-4799-1963-5, (2015), S. 193-196
http://dx.doi.org/10.1109/CAMSAP.2015.7383769
Detection of time-varying support via rank evolution approach for effective joint sparse recovery. - In: 2015 23rd European Signal Processing Conference (EUSIPCO), ISBN 978-0-9928626-3-3, (2015), S. 1716-1720
http://dx.doi.org/10.1109/EUSIPCO.2015.7362677
An adaptively focusing measurement design for compressed sensing based DOA estimation. - In: 2015 23rd European Signal Processing Conference (EUSIPCO), ISBN 978-0-9928626-3-3, (2015), S. 859-863
http://dx.doi.org/10.1109/EUSIPCO.2015.7362505
Wave-field synthesis from theory to practice - an analysis of implementation deficiencies. - In: 2nd International Scientific Symposium "Sense. Enable. SPITSE." 2015, 22 June - 03 July 2015, ISBN 978-5-7629-1647-9, (2015), S. 75-78
DoA estimation with reflectarray according to single pixel camera principle. - In: 2015 3rd International Workshop on Compressed Sensing Theory and Its Applications to Radar, Sonar and Remote Sensing (CoSeRa), ISBN 978-1-4799-7420-7, (2015), S. 268-272
http://dx.doi.org/10.1109/CoSeRa.2015.7330306
Land mobile satellite propagation characteristics from knife-edge diffraction modeling and hemispheric images. - In: 2015 9th European Conference on Antennas and Propagation (EuCAP 2015), (2015), S. 3346-3349
Sparsity order estimation for sub-Nyquist sampling and recovery of sparse multiband signals. - In: 2015 IEEE International Conference on Communications (ICC), (2015), S. 4907-4912
http://dx.doi.org/10.1109/ICC.2015.7249100
On the design of the measurement matrix for Compressed Sensing based DOA estimation. - In: 2015 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), ISBN 978-1-4673-6998-5, (2015), S. 3631-3635
http://dx.doi.org/10.1109/ICASSP.2015.7178648
Emulation of virtual radio environments for realistic end-to-end testing for intelligent traffic systems. - In: 2015 IEEE MTT-S International Conference on Microwaves for Intelligent Mobility (ICMIM), ISBN 978-1-4799-7215-9, (2015), insges. 4 S.
http://dx.doi.org/10.1109/ICMIM.2015.7117934
Parametric spatial sound processing : a flexible and efficient solution to sound scene acquisition, modification, and reproduction. - In: IEEE signal processing magazine, ISSN 1558-0792, Bd. 32 (2015), 2, S. 31-42
https://doi.org/10.1109/MSP.2014.2369531
Modeling of the Land Mobile Satellite channel considering the terminal's driving direction. - In: International journal of antennas and propagation, ISSN 1687-5877, Bd. 2015 (2015), Article ID 372124, insges. 21 S.
http://dx.doi.org/10.1155/2015/372124
Link adaptation for LTE-A systems employing MMSE turbo equalization. - In: WSA 2014, (2014), insges. 7 S.
http://ieeexplore.ieee.org/document/6776891/
Polarimetric compressive sensing based DOA estimation. - In: WSA 2014, (2014), insges. 8 S.
http://ieeexplore.ieee.org/document/6776890/
Sparsity order estimation for single snapshot compressed sensing. - In: 48th Asilomar Conference on Signals, Systems and Computers, 2014, ISBN 978-1-4799-8298-1, (2014), S. 1220-1224
http://dx.doi.org/10.1109/ACSSC.2014.7094653
On the sensing matrix performance for support recovery of noisy sparse signals. - In: IEEE Global Conference on Signal and Information Processing (GlobalSIP), 2014, ISBN 978-1-4799-7089-6, (2014), S. 679-683
http://dx.doi.org/10.1109/GlobalSIP.2014.7032204
An empirical eigenvalue-threshold test for sparsity level estimation from compressed measurements. - In: Proceedings of the 22nd European Signal Processing Conference (EUSIPCO), 2014, ISBN 978-1-4799-4603-7, (2014), S. 1761-1765
http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=&arnumber=6952632
Accuracy of an OTA system emulating a realistic 3D environment for GNSS and multi-satellite receiver testing. - In: 2014 IEEE 8th Sensor Array and Multichannel Signal Processing Workshop (SAM), ISBN 978-1-4799-1481-4, (2014), S. 113-116
http://dx.doi.org/10.1109/SAM.2014.6882353
Virtual electromagnetic environment for over-the-air testing of car-to-car and car-to-infrastructure communication. - In: XXXIth URSI general assembly and scientific symposium (URSI GASS), 2014, ISBN 978-1-4673-5225-3, (2014), insges. 4 S.
http://dx.doi.org/10.1109/URSIGASS.2014.6929561
On arranging dual-polarised antennas in 3D wave field synthesis. - In: 8th European Conference on Antennas and Propagation (EuCAP), 2014, ISBN 978-1-4799-2431-8, (2014), S. 3406-3410
http://dx.doi.org/10.1109/EuCAP.2014.6902560
3D wave-field synthesis for testing of radio devices. - In: 8th European Conference on Antennas and Propagation (EuCAP), 2014, ISBN 978-1-4799-2431-8, (2014), S. 3394-3398
http://dx.doi.org/10.1109/EuCAP.2014.6902557
Diversity combining for cooperative satellite terminals in a moving convoy of vehicles. - In: 8th European Conference on Antennas and Propagation (EuCAP), 2014, ISBN 978-1-4799-2431-8, (2014), S. 3035-3039
http://dx.doi.org/10.1109/EuCAP.2014.6902467
Impact of driving direction on Land Mobile Satellite channel modeling. - In: 8th European Conference on Antennas and Propagation (EuCAP), 2014, ISBN 978-1-4799-2431-8, (2014), S. 2268-2271
http://dx.doi.org/10.1109/EuCAP.2014.6902266
R-dimensional ESPRIT-type algorithms for strictly second-order non-circular sources and their performance analysis. - In: IEEE transactions on signal processing, ISSN 1941-0476, Bd. 62 (2014), 18, S. 4824-4838
http://dx.doi.org/10.1109/TSP.2014.2342673
Tensor-based algorithms for learning multidimensional separable dictionaries. - In: IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), 2014, ISBN 978-1-4799-2894-1, (2014), S. 2963-2967
http://dx.doi.org/10.1109/ICASSP.2014.6854345
On the estimation of grid offsets in CS-based direction-of-arrival estimation. - In: IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), 2014, ISBN 978-1-4799-2894-1, (2014), S. 6776-6780
http://dx.doi.org/10.1109/ICASSP.2014.6854912
Analytical performance assessment of multi-dimensional matrix- and tensor-based ESPRIT-type algorithms. - In: IEEE transactions on signal processing, ISSN 1941-0476, Bd. 62 (2014), 10, S. 2611-2625
http://dx.doi.org/10.1109/TSP.2014.2313530
Multi-directional Over The Air testbed for robustness testing of GNSS receivers against Jammers and Spoofers. - In: 31st AIAA International Communications Satellite Systems Conference (ICSSC-2013), ISBN 978-1-62993-432-7, (2013), S. 114-128
Performance comparison of antenna de-pointing estimation methods for SOTM terminal testing. - In: 31st AIAA International Communications Satellite Systems Conference (ICSSC-2013), ISBN 978-1-62993-432-7, (2013), S. 639-649
On-earth performance evaluation of SatCom On-The-Move (SOTM) terminals. - In: 2013 IEEE Military Communications Conference, ISBN 978-1-4799-4899-4, (2013), S. 634-640
http://dx.doi.org/10.1109/MILCOM.2013.114
Parametric spatial audio reproduction with higher-order B-format microphone input. - In: 134th Audio Engineering Society convention 2013, ISBN 978-1-62748-571-5, (2013), S. 830-839
A robust audio watermarking system for acoustic channels. - In: Journal of the Audio Engineering Society, ISSN 1549-4950, Bd. 61 (2013), 11, S. 878-888
Satcom on the move (SOTM) terminals evaluation under realistic conditions. - In: IEEE 77th Vehicular Technology Conference (VTC Spring), 2013, ISBN 978-1-4673-6336-5, (2013), insges. 5 S.
http://dx.doi.org/10.1109/VTCSpring.2013.6692740
Measurement-based performance analysis of cooperative diversity for satellite terminals in a moving convoy. - In: IEEE 77th Vehicular Technology Conference (VTC Spring), 2013, ISBN 978-1-4673-6336-5, (2013), insges. 5 S.
In this paper we discuss the impact of cooperative satellite diversity on the availability of the land mobile satellite (LMS) channel. By the use of multiple terminals the overall probability to encounter conditions where all terminals are in a bad channel state is reduced. This reduction depends on the number of terminals and the terminal distance. The results presented in this paper are completely based on the analysis of measurements. These were conducted for two geostationary satellites and four different environments using a single mobile satellite terminal. Thus, in order to virtually increase the number of terminals we rely on a convoy scenario using shifted versions of the data. Analyzing up to four cooperative terminals and different terminal distances a significant bad state reduction is already achieved for rather small distances.
http://dx.doi.org/10.1109/VTCSpring.2013.6692630
Over-the-air testing of cognitive radio nodes in a virtual electromagnetic environment. - In: International journal of antennas and propagation, ISSN 1687-5877, Bd. 2013 (2013), Article ID 945283, insges. 16 S.
http://dx.doi.org/10.1155/2013/945283
Over-the-air testing of Car-to-Car and Car-to-Infrastructure communication in a virtual electromagnetic environment. - In: IECON 2013, ISBN 978-1-4799-0224-8, (2013), S. 6897-6902
http://dx.doi.org/10.1109/IECON.2013.6700275
Performance analysis of channel model simplifications for MIMO OTA LTE UE testing. - In: 7th European Conference on Antennas and Propagation (EuCAP), 2013, ISBN 978-1-4673-2187-7, (2013), S. 1856-1860
http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6546610
High time-resolution spectrum occupancy model for testing of cognitive radio devices. - In: IEEE 24th International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), 2013, ISBN 978-1-4673-6233-7, (2013), S. 596-600
http://dx.doi.org/10.1109/PIMRC.2013.6666206
Influence of driving direction on land mobile satellite channels. - In: IEEE International Symposium on Broadband Multimedia Systems and Broadcasting (BMSB), 2013, ISBN 978-1-4673-6047-0, (2013), insges. 5 S.
http://dx.doi.org/10.1109/BMSB.2013.6621686
Realistic emulation of the operational environment for SatCom On-The-Move (SOTM) terminals. - In: IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC), 2013, ISBN 978-1-4799-2658-9, (2013), S. 1115-1118
http://dx.doi.org/10.1109/APWC.2013.6624928
State modeling of the land mobile satellite channel by an image-based approach. - In: 7th European Conference on Antennas and Propagation (EuCAP), 2013, ISBN 978-1-4673-2187-7, (2013), S. 672-676
http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=&arnumber=6546359
Directional analysis with microphone array mounted on rigid cylinder for directional audio coding. - In: Journal of the Audio Engineering Society, ISSN 1549-4950, Bd. 60 (2012), 5, S. 311-324
Impact of the receive antenna arrays on spatio-temporal availability in satellite-to-indoor broadcasting. - In: IEEE transactions on broadcasting, ISSN 1557-9611, Bd. 56 (2010), 2, S. 171-183
http://dx.doi.org/10.1109/TBC.2010.2046432
A novel environment characterization metric for clustered MIMO channels : used to validate a SAGE parameter estimator. - In: Wireless personal communications, ISSN 1572-834X, Bd. 46 (2008), 1, S. 83-98
http://dx.doi.org/10.1007/s11277-007-9357-1
Higher-order SVD-based subspace estimation to improve the parameter estimation accuracy in multidimensional harmonic retrieval problems. - In: IEEE transactions on signal processing, ISSN 1941-0476, Bd. 56.2008, 7, Pt. 2, S. 3198-3213
http://dx.doi.org/10.1109/TSP.2008.917929
Channel representative interference cancellation (CRIC) for MIMO multi-hop systems in the Manhattan scenario. - In: IEEE International Conference on Acoustics, Speech and Signal Processing, 2008, ISBN 978-1-4244-1483-3, (2008), S. 1613-1616
http://dx.doi.org/10.1109/ICASSP.2008.4517934
Tensor-based framework for the prediction of frequency-selective time-variant MIMO channels. - In: International ITG Workshop on Smart Antennas, 2008, ISBN 978-1-4244-1757-5, (2008), S. 147-152
http://dx.doi.org/10.1109/WSA.2008.4475550
Quality of service oriented spatial processing in the Manhattan grid. - In: International ITG Workshop on Smart Antennas, 2008, ISBN 978-1-4244-1757-5, (2008), S. 362-369
http://dx.doi.org/10.1109/WSA.2008.4475583
Receive antenna impact on spatio-temporal availability in satellite-to-indoor broadcasting. - In: International ITG Workshop on Smart Antennas, 2008, ISBN 978-1-4244-1757-5, (2008), S. 48-54
http://dx.doi.org/10.1109/WSA.2008.4475536
Holographische Modalanalyse mit skalierbarem Kugelarray. - In: Fortschritte der Akustik, ISBN 978-3-9808659-3-7, (2007), S. 885-886
Geometry-based channel modelling for multi-user MIMO systems and applications. - Ilmenau : ISLE, 2007. - Online-Ressource (PDF-Datei: XIX, 274 S., 13,96 MB). - (Research reports from the Communications Reseach Laboratory at Ilmenau University of Technology) : Ilmenau, Techn. Univ., Diss., 2007
ISBN 978-3-938843-27-7
Parallel als Druckausg. erschienen
Im Rahmen dieser Dissertation wird die Kanalmodellierung von zeitvarianten, frequenzselektiven Mehrnutzer Multiple Input Multiple Output (MIMO) Kanälen für die Funkübertragung behandelt. Durch eine Erweiterung der Bello Funktionen mit Hilfe von Tensoren wird die multidimensionale Dispersion des Funkkanals dargestellt. Es werden einige der wichtigsten Ansätze zur Kanalmodellierung vorgestellt und klassifiziert. Für geometrische Kanalmodelle ist es entscheidend die Richtcharakteristika der Antennen im Fernfeld genau und effizient zu beschreiben. Zu diesem Zweck wird ein neues Beschreibungsverfahren entwickelt, das auf der Discrete Vector Spherical Fourier Transform (DVSFT) basiert. Dadurch ist es möglich, eine höhere Genauigkeit bei der Beschreibung von komplexen Vektorfunktionen auf der Kugel zu erreichen. Die vorgeschlagene Methode führt zu neuen Anwendungsmöglichkeiten. Der Schwerpunkt dieser Dissertation ist IlmProp: ein Geometrie-basiertes Framework zur Kanalmodellierung. Es füllt die Lücke zwischen konventionellen direktionalen Kanalmodellen und so genannten "Ray-Tracer"Kanalmodellen. IlmProp ermöglicht es gleichzeitig mehrere Nutzer in der selben Umgebung zu simulieren. Mehrwege-Komponenten werden an Hand von punktförmigen Wechselwirkungsobjekten, so genannten Interacting Objects (IOs), modelliert. Dadurch wird die zeitliche Variation der Korrelation in Zeit, Frequenz, Raum und zwischen den Nutzern realitätsnah modelliert. Die Parameter des IlmProp Kanalmodells können willkürlich gesetzt oder aus hochauflösenden Parameterschatzverfahren gewonnen werden. Im ersten Fall kann IlmProp dazu genutzt werden, verschiedene Sende, Empfangs und SchedulingAlgorithmen zu testen. Um aus hochauflosenden Parameterschatzungen die IlmPropParameter zu gewinnen, wurde ein neuartiger Algorithmus entwickelt, der die IOs aus Einfalls- und Austritts-winkel und der Ausbreitungszeit lokalisiert.Dies macht IlmProp zu einem leistungsfähigen Visualisierungswerkzeug, um Kanalmessungen zu validieren und um die Ausbreitungsbedingung des Szenarios zu untersuchen. Im weiteren Verlauf der Arbeit wird das so genannte Measurement-Based Parametric Channel Model (MBPCM), verbessert. Es ermöglicht durch eine antennenunabhängige, doppelt-direktionale Kanalbeschreibung, aus vorhandenen Kanalmessungen zusätzliche realitätsnahe, synthetische Kanalrealisierungen zu erzeugen.
http://www.db-thueringen.de/servlets/DocumentServlet?id=11002
Enhanced model order estimation using higher-order arrays. - In: Conference record of the Forty-First Asilomar Conference on Signals, Systems and Computers, 2007, ISBN 978-1-4244-2109-1, (2007), S. 412-416
https://doi.org/10.1109/ACSSC.2007.4487242
Spatio-temporal availability in satellite-to-indoor broadcasting. - In: European Conference on Wireless Technologies, 2007, ISBN 978-2-87487-003-3, (2007), S. 162-165
http://dx.doi.org/10.1109/ECWT.2007.4403971
Low-complexity space-time-frequency scheduling for MIMO systems with SDMA. - In: IEEE transactions on vehicular technology, ISSN 1939-9359, Bd. 56 (2007), 5, S. 2775-2784
http://dx.doi.org/10.1109/TVT.2007.898382
Holographic sound field analysis with a scalable spherical microphone-array. - In: 122nd Audio Engineering Society Convention 2007, (2007), S. 630-636
MIMO capability of a miniaturised antenna array with a decoupling and matching network. - In: International ITG/IEEE Workshop on Smart Antennas, (2007), insges. 6 S.
Deterministic Cramér-Rao bounds for strict sense non-circular sources. - In: International ITG/IEEE Workshop on Smart Antennas, (2007), insges. 5 S.
A correlation tensor based model for time variant frequency selective MIMO channels. - In: International ITG/IEEE Workshop on Smart Antennas, (2007), insges. 7 S.
Spatial localization of scattering objects from high-resolution parameter estimates. - In: NEWCOM - ACoRN Joint Workshop 2006, (2006), insges. 5 S.
A novel environment characterisation metric for clustered MIMO channels used to validate a SAGE parameter estimator. - In: 15th IST Mobile and Wireless Summit, Myconos, Greece, 4 - 8 June 2006, (2006), insges. 5 S.
Higher order SVD based subspace estimation to improve multi-dimensional parameter estimation algorithms. - In: Fortieth Asilomar Conference on Signals, Systems and Computers, 2006, (2006), S. 961-965
http://dx.doi.org/10.1109/ACSSC.2006.354894
Estimation of reflection coefficients for the IlmProp channel modeling environment using path loss models. - In: Information technology and electrical engineering - devices and systems, materials and technologies for the future, (2006), insges. 10 S.
http://www.db-thueringen.de/servlets/DocumentServlet?id=13112
Low complexity spatial scheduling ProSched for MIMO systems with multiple base stations and a central controller. - In: WSA 2006, (2006), insges. 8 S.
Cluster spatial localization from high-resolution parameter estimation. - In: WSA 2006, (2006), insges. 4 S.
A novel automatic cluster tracking algorithm. - In: IEEE 17th International Symposium on Personal, Indoor and Mobile Radio Communications, 2006, (2006), insges. 5 S.
http://dx.doi.org/10.1109/PIMRC.2006.254347
Subspace-based framework for the prediction of MIMO OFDM channels. - In: Proceedings, (2006), insges. 5 S.
Modelling and manipulation of polarimetric antenna beam patterns via spherical harmonics. - In: EUSIPCO 2006, (2006), insges. 5 S.
Spatial availability in satellite-to-indoor broadcasting communications. - In: 7th Workshop Digital Broadcasting, (2006), S. 113-118
A novel tree-based scheduling algorithm for the downlink of multi-user MIMO systems with ZF beamforming. - In: 2005 IEEE International Conference on Acoustics, Speech, and Signal Processing, (2005), S. III-1121-III-1124
https://doi.org/10.1109/ICASSP.2005.1415911
Efficient multi-user MIMO downlink precoding and scheduling. - In: 1st IEEE International Workshop on Computational Advances in Multi-Sensor Adaptive Processing, 2005, (2005), S. 237-240
http://dx.doi.org/10.1109/CAMAP.2005.1574228
An interim channel model for beyond-3G systems : extending the 3GPP spatial channel model (SCM). - In: Proceedings, (2005), S. 3132-3136
MATLAB implementation of the 3GPP spatial channel model : (3GPP TR 25.996). - In: 12th COST 273 MC Meeting, 2005, TD(05)030, insges. 18 S.
Performance evaluation of ultra-wide band compared to wireless infrared communications. - In: Conference proceedings, (2005), S. 193-196
Efficient channel modelling for frequency selective MIMO channels. - In: ITG Workshop on Smart Antennas, 2004, (2004), S. 189-193
http://dx.doi.org/10.1109/WSA.2004.1407667
Geometry-based channel modelling of MIMO channels in comparison with channel sounder measurements. - In: Advances in radio science, ISSN 1684-9973, Bd. 2 (2004), S. 117-126
http://dx.doi.org/10.5194/ars-2-117-2004
Increasing the throughput in multi-hop wireless networks by using spatial multiplexing. - In: Proceedings, (2004), S. 2627-2631
Comparison of zero-forcing methods for downlink spatial multiplexing in realistic multi-user MIMO channels. - In: Proceedings, (2004), S. 299-303
A subspace-based channel model for frequency selective time variant MIMO channels. - In: Proceedings, (2004), S. 1603-1607
Efficient antenna description for MIMO channel modelling and estimation. - In: Wireless technologies 2004, (2004), S. 217-220
Analysis of MIMO channel measurements. - In: IFAC Proceedings Volumes, ISSN 1474-6670, Bd. 36 (2003), 16, S. 85-89
https://doi.org/10.1016/S1474-6670(17)34743-2
Advanced geometry-based modeling for MIMO scenarios in comparison with real measurements. - In: Proceedings and our portrait, (2003), insges. 9 S.
Realistic MIMO simulations based on multidimensional channel-sounding measurements. - In: XXVIIth general assembly