CSI-based localization with CNNs exploiting phase information. - In: 2021 IEEE Wireless Communications and Networking Conference (WCNC), (2021), insges. 6 S.
In this paper we study the use of the Channel State Information (CSI) as fingerprint inputs of a Convolutional Neural Network (CNN) for localization. We examine whether the CSI can be used as a distinct fingerprint corresponding to a single position by considering the inconsistencies with its raw phase that cause the CSI to be unreliable. We propose two methods to produce reliable fingerprints including the phase information. Furthermore, we examine the structure of the CNN and more specifically the impact of pooling on the positioning performance, and show that pooling over the subcarriers can be more beneficial than over the antennas.
https://doi.org/10.1109/WCNC49053.2021.9417561
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
Practical aspects on the noise floor estimation and cut-off margin in channel sounding applications. - In: Focus on linking antennas and propagation with the automotive and 5G industries, (2021), insges. 5 S.
The characterization of propagation at mm-waves and THz is obtaining relevance since they are expected to be the frequency bands of the future wireless generations. Hence, measurements conducted all around the world with different equipments need to be comparable by establishing common methodologies and best-practice guidelines. As an example, all measurements are affected by noise, but its estimation and removal are not standardized. Therefore, in the present paper we define a methodology on the estimation of the noise floor and the cut-off margin for its subsequent removal. We firstly analyse the influence of the channel sounder noise floor on the estimation of different propagation parameters directly from the measured channel impulse responses (CIRs), showing the need of its removal before any processing of the measurements. Later, we introduce an algorithm to estimate the noise floor in the presence of signal, and the cut-off margin. Finally, we evaluate its performance empirically with measurements.
https://doi.org/10.23919/EuCAP51087.2021.9411409
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
Advances on the detection of landmines and IEDs in Colombia using UWB GPR and machine learning techniques. - In: Focus on linking antennas and propagation with the automotive and 5G industries, (2021), insges. 4 S.
In this paper we present the latest results of a research program on the use of ground penetrating radar and machine learning-based algorithms for humanitarian demining in Colombia. We describe the experimental setup developed, which includes a polarimetric GPR-UWB unit, a radar positioning system, and a control unit. We describe as well a soil characterization campaign and an IED classification technique based on Support Vector Machine.
https://doi.org/10.23919/EuCAP51087.2021.9411214
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