Ales Prokes

• Brno University of Technology

Long/short-term memory (LSTM) is a deep learning model that can capture long-term dependencies of wireless channel models and is highly adaptable to short-term changes in a wireless environment. This paper proposes a simple LSTM model to predict the channel transfer function (CTF) for a given transmitter-receiver location inside a bus for the 60 GH...

The spatial statistics of radio wave propagation in specific environments and scenarios, as well as being able to recognize important signal components, are prerequisites for dependable connectivity. There are several reasons why in-vehicle communication is unique, including safety considerations and vehicle-to-vehicle/infrastructure communication....

This paper introduces an approach to process channel sounder data acquired from Channel Impulse Response (CIR) of 60GHz and 80GHz channel sounder systems, through the integration of Long Short-Term Memory (LSTM) Neural Network (NN) and Fully Connected Neural Network (FCNN). The primary goal is to enhance and automate cluster detection within peaks...

Fifth generation (5G) new radio is now offering sidelink capability, which allows direct vehicle-to-vehicle (V2V) communication. Millimeter wave (mmWave) enables low-latency mission-critical V2V communications, such as forward crash warning, between two vehicles crossing on a road without dividers. In this article, we present a measurement-based pa...

In this letter, we examine the effect of misalignment angle on cluster-based power delay profile (PDP) modeling for a 60 GHz millimeter-wave uplink. The analysis uses real-world data, where fixed uplink scenarios are realized by placing the transmitter at ground level and the receiver at the building level. Both outdoor-to-indoor (O2I) and outdoor-...

This paper presents a comprehensive measurement campaign aimed at evaluating indoor-to-indoor radio channels in dynamic scenarios, with a particular focus on applications such as autonomous ground vehicles (AGV). These scenarios are characterized by the height of the antennas, addressing the unique challenges of near-ground communication. Our study...

Millimeter wave (mmWave) technology offers high throughput but has a limited radio range, necessitating the use of directional antennas or beamforming systems such as massive MIMO. Path loss (PL) models using narrow-beam antennas are known as directional models, while those using omnidirectional antennas are referred to as omnidirectional models. T...

In this paper, we analyze the spectral efficiency for millimeter wave downlink with beam misalignment in urban macro scenario. For this purpose, we use a new approach based on the modified Shannon formula, which considers the propagation environment and antenna system coefficients. These factors are determined based on a multi-ellipsoidal propagati...

In this paper, we present an empirical verification of the method of determining the Doppler spectrum (DS) from the power angular spectrum (PAS). Measurements were made for the frequency of 3.5 GHz, under non-line-of-sight conditions in suburban areas characteristic of a university campus. In the static scenario, the measured PAS was the basis for...

In this paper, we examine the effect of misalignment angle on cluster-based power delay profile modeling for a 60 GHz millimeter-wave (mmWave) uplink. The analysis uses real-world data, where fixed uplink scenarios are realized by placing the transmitter at ground level and the receiver at the building level. Both outdoor-to-indoor (O2I) and outdoo...

The deployment of wireless systems in millimeter wave relies on a thorough understanding of electromagnetic wave propagation under various weather conditions and scenarios. In this study, we characterize millimeter wave propagation effects from measurement data, utilizing channel impulse response analysis with a focus on root mean square delay spre...

Since the design of wireless MIMO systems requires knowledge of the double-directional (i.e., directionally resolved at both link ends) channel characteristics, and 5G/6G use higher frequency bands, there is the need for double-directional measurements in the mmWave spectrum, along with channel sounders that can accurately perform such measurements...

Supercapacitors attract attention due to their superior values in the parameters like capacitance, discharge currents and cycle lifespan. Supercapacitors are designed and used in many applications where they partially or completely substitute conventional batteries. On the other side, supercapacitors are used in applications which are not so far su...

We present two datasets for Machine Learning (ML)-based Predictive Quality of Service (PQoS) comprising Vehicle-to-Infrastructure (V2I) and Vehicle-to-Vehicle (V2V) radio channel measurements. As V2V and V2I are both indispensable elements for providing connectivity in Intelligent Transport Systems (ITS), we argue that a combination of the two data...

Radio wave propagation in an intra-vehicular (IV) environment is markedly different from other well-studied indoor scenarios, such as an office or a factory floor. While millimetre wave (mmWave)-based intra-vehicular communications promise large bandwidth and can achieve ultra-high data rates with lower latency, exploiting the advantages of mmWave...

Fifth generation new radio (5G NR) is now offering sidelink capability, which allows direct vehicle-to-vehicle (V2V) communication. Millimeter wave (mmWave) enables low-latency mission-critical V2V communications, such as forward crash warning, between two vehicles crossing on a road without dividers. In this article, we present a measurement-based...

In this paper, we present an empirical verification of the method of determining the Doppler spectrum (DS) from the power angular spectrum (PAS). Measurements were made for the frequency of 3.5 GHz, under non-line-of-sight conditions in suburban areas characteristic of a university campus. In the static scenario, the measured PAS was the basis for...

Radio wave propagation in an intra-vehicular environment is markedly different from other well studied indoor scenarios such as an office or a factory oor. Millimeter Wave (mmWave) based intra-vehicular communications promises large bandwidth and can achieve ultra-high data rate with lower latency. However, exploiting the advantages of mmWave commu...

In this article we have utilized deep learning (DL) for channel sounding application in the millimeter wave (mmWave) band. Using data from a channel sounding campaign for studying intra-vehicle wireless channels operating over the 55-65 GHz mmWave band, we have trained an artificial neural network (ANN) model, which is used to simulate power-delay-...

The basic technology that will determine the expansion of the technical capabilities of fifth generation cellular systems is a massive multiple-input-multiple-output. Therefore, assessing the influence of the antenna beam orientations on the radio channel capacity is very significant. In this case, the effects of mismatching the antenna beam direct...

In emerging fifth-generation (5G) networks, millimeter-wave bands will be used. Due to high atmospheric attenuation, the 60 GHz band is planned to be used for indoor and outdoor line-of-sight communication. Numerous uses of this band for vehicle-to-infrastructure (V2I) connectivity are indicated in the literature. In this paper, we propose a novel...

In this paper, the measurement data of an outdoor-to-indoor channel at 60 GHz for various orientations of the receiver is analyzed. We comment on the variation of the received line-of-sight (LOS) component power and delay spread with respect to the misalignment angle and suggest the existence of clusters which map to nearby buildings acting as scat...

This paper analyzes a scenario where single or multiple sensors placed on a parked car help the owner to find the car in a parking lot. It is assumed that the sensors communicate with the owner device over ultra-wide-band (UWB)and the owner device only records the received signal strength(RSS) values. Based on the RSS data, which are obtained from...

In this paper, we study the time-variance of a roadside infrastructure to infrastructure (I2I) channel operating at 60 GHz millimetre wave (mmWave) band, where the time-variance is caused by moving vehicles acting as scatterers. At first, measurement data is obtained by placing the transmitter (TX) and the receiver (RX) at different heights to emul...

In this paper, a novel method for improving the estimation accuracy of the root mean square (RMS) delay spread from the magnitude of the Channel Transfer Function (CTF) is presented. We utilize the level crossing rate metric in the frequency domain, which is based on scalar power measurement. The Savitzky–Golay (S-G) filtering method is used to imp...

The paper deals with an analysis of multipath propagation environment in the 60 GHz band using a pseudo-random binary sequence-based time-domain channel sounder with 8 GHz bandwidth. The main goal of this work is to analyze the multipath components (MPCs) propagation between a moving car carrying a transmitter with an omnidirectional antenna and a...

Millimeter-wave (mmWave) transmission over the unlicensed 60 GHz spectrum is a potential solution to realize high-speed internet access, even inside mass transit vehicles. The solution involves communication between users and a mmWave-band on-board unit which aggregates/ disseminates data streams from/ to commuters, and maintains connection with th...

This paper analyzes the data obtained from a 60 GHz infrastructure-to-infrastructure millimetre wave channel sounding campaign, carried out in an urban-highway environment in Brno, Czech Republic. The transmitter and the receiver are placed at different heights to emulate a link between a typical base station and a roadside unit while the passing v...

This study describes a time domain channel sounder based on binary sequences. The channel sounder system consists of several off-the-shelf laboratory instruments and is controlled by a PC. The frequency band of interest is the unlicensed millimetre wave band, 57-64 GHz. A crucial feature of the proposed system is its fast measurement speed enabling...

We report results from millimeter wave vehicle-to-infrastructure (V2I) channel measurements conducted on Sept. 25, 2018 in an urban street environment, down-town Vienna, Austria. Measurements of a frequency-division multiplexed multiple-input single-output channel have been acquired with a time-domain channel sounder at 60 GHz with a bandwidth of 1...

The time-variant vehicle-to-vehicle radio propagation channel in the frequency band from 59.75 GHz to 60.25 GHz has been measured in an urban street in the city center of Vienna, Austria. We have measured a set of 30 vehicle-to-vehicle channel realizations to capture the effect of an overtaking vehicle. Our experiment was designed for characterizin...

The 5G vision acknowledges intravehicular communication as a means to enable passenger connectivity on the move. The capacity demand in a public transport vehicle is multi-fold compared to personal cars as there are more people on-board. In order to meet the demand, 5G standardization bodies prescribe moving the spectrum up to the millimetre wave (...

Saleh-Valenzuela based clustered propagation concept is widely adopted for modelling UWB channels operating in the 3-11 GHz band. In this paper, we examine whether 60 GHz mmWave channels can be modelled along the same line. First, an automatic clustering algorithm is developed for the purpose which groups multipath components according to their tim...

Free-space optical (FSO) links are considered as cost-effective, non-invasive alternative to fiber optic cables for 5G cellular backhaul networking. For FSO based backhaul networks we propose an additional millimeter-wavelength (MMW) radio-frequency (RF)-FSO link, used as a backup. Uninterrupted and reliable network connection is possible by switch...

Lightning Talk, N2Women and WICE workshop

The randomness in UWB channel for small positional variations around a car, parked in an underground garage, is reported. Keeping the receiver fixed at the conventional rooftop antenna location, the transmitter location is changed to study the variations against distance, angle, and height. The path loss is found to be monotonically increasing with...

The paper provides real-word wireless measurement data of the intra-vehicular channel for both the 3-11 GHz and the 55-65 GHz frequency band under similar conditions. By spatially averaging channel impulse response (CIR) realizations within a 10×10 grid, we obtain the power-delay profile (PDP). The data measured at 3-11 GHz and 55-65 GHz exhibit si...

Detonation velocity (VOD) is one of the most important parameters describing the detonation process of a particular explosive. This article summarizes some peculiarities that we have come across when building and testing our new passive optical VOD meter - OPTIMEX. The advantages of using multiple probes with independent signal recording is discuss...

The ability of a newly developed independent passive optical system OPTIMEX to measure the detonation front curvature is demonstrated on charges of pressed explosive A-IX-1 (RDX/ceresin-stearin mixture with 95/5 wt.%). The charges, with length to diameter ratios of from one to four, were prepared from cylinders with diameters of 21 mm, 30 mm, 40 mm...

The article presents out-of-vehicle channel measurement results in ultra-wide band spanning 3–11 GHz bandwidth using a vector network analyzer for localization applications. Experiments for different distances and different angles around the parked car are carried out. From the power delay profiles, the distance between the antennas is calculated e...

The characteristics of the transmission channel inside the car are very important for future intra-car communication technologies. These technologies will create the small wireless networks for the distribution of data services such as internet, video, audio, etc. transmission. For these services, it is preferable to use the UWB frequency band from...

In this work, antennas utilized for an intra-vehicle 3–11 GHz and 55–65 GHz channel measurement are described. A measurement antenna should not only provide a wide-band impedance bandwidth but also have a stable radiation pattern and a high fidelity factor. For the lower frequency band, a metal conical monopole antenna is proposed for its frequency...

Intra vehicular communication is an emerging field of research due to its potential applications in safety of passengers, navigational and localization aids for driver, and multimedia infotainment. This chapter describes the wireless channel sounding activities performed inside a typical passenger car under the SoMoPro and the GACR projects. Three...

The aim of this article is to present a simple but robust model characterizing the frequency dependent transfer function of an in-vehicle ultra-wide-band channel. A large number of transfer functions spanning the ultra-wide-band (3 GHz to 11 GHz) are recorded inside the passenger compartment of a four seated sedan car. It is found that the complex...

In this paper, we investigate the detection performance of cooperative spectrum sensing (CSS) using energy detector (ED) in several fading scenarios. The fading environments comprises of relatively less-studied Hoyt and Weibull channels in addition to the conventional Rayleigh, Rician, Nakagami-m, and log-normal shadowing channels. We have presente...

This paper reports on a real-world wireless channel measurement campaign for in-vehicle scenarios in the UWB frequency range of 3 to 11 GHz. The effects of antenna placement in the vehicle’s passenger compartment as well as the effects due to the presence of passengers are studied. The measurements have been carried out in the frequency domain, and...

Ultra-wide band (UWB) communication is expected to play a key role in next generation broadband intra vehicle wireless applications. The car compartment differs significantly from other well studied indoor or outdoor environments. Hence, channel sounding experiments are crucial for gaining a thorough knowledge of the UWB signal propagation characte...

The article presents out-of-vehicle channel measurement results in the 5.8 GHz frequency band which is used in the IEEE 802.11p standard. Experiments for two different distances and three different angles around the parked car are carried out. It is found that a two-term exponential decay model can satisfactorily describe the mean measured power de...

This paper provides a comparison of a real-world intra-vehicular radio channel measurements of the ultra-wide frequency bands, namely the 3-11 GHz and the 55-65 GHz. The measurement campaign was performed utilizing a vector network analyzer (VNA) and a frequency domain method ensuring a high dynamic range of 70 dB and a frequency resoluton of 10 MH...

The goal of this paper is to characterize frequency domain channel transfer function of intra vehicular millimeter wave links in the 60 GHz band. It is found that the complex transfer function may be decomposed into two terms, the first one being a real valued long term trend that characterizes frequency dependency with a power law, and the second...

The paper deals with intra-vehicle ranging based on the time of arrival technique. The aim of the presented work is to compare the ranging accuracy in the 3 to 11 GHz ultra-wide band and the 56 to 64 GHz millimeter wave band. The comparison is performed using channel impulse responses calculated from complex transfer functions using a windowed IFFT...

The aim of this article is to simulate bit error rate (BER) of the IEEE 802.11p standard with different numbers of transmit and receive antennas. Assuming a simple flat Rayleigh fading channel, we have investigated three different antenna settings, namely, single input single output (SISO), multiple input single output (MISO), and multiple input mu...

This article reports results of channel frequency transfer function measurements inside the passenger compartment of a four seated sedan car. The examined frequency range spans from 3 GHz to 11 GHz and covers the ultra wide band, a promising candidate for future automotive wireless standards. It is found that the complex transfer function may be de...

This paper describes a time domain channel sounder based on pseudorandom binary sequences. The channel sounder system consists of several off-the-shelf laboratory instruments connected together and controlled from PC. Frequency band of interest is the unlicensed ultra wide band, 3-11 GHz. The system's parameters are discussed and compared to conven...

The article reports vehicular channel measurements in the frequency band of 5.8 GHz for IEEE 802.11p standard. Experiments for both intra-vehicle and out-of-vehicle environments were carried out. It was observed that the large-scale variations (LSVs) of the power delay profiles (PDPs) can be best described through a two-term exponential decay model...

A comparison of two variants of CLEAN, a time-domain serial subtractive deconvolution algorithm, is presented. Appropriate statistical metrics for assessing the relative merit of the deconvolution technique are identified in the context of intra vehicle ultra wide band transmission, and the better variant was selected based on its performance over...

A comparison of two variants of CLEAN, a time-domain serial subtractive deconvolution algorithm, is presented. Appropriate statistical metrics for assessing the relative merit of the deconvolution technique are identified in the context of intra vehicle ultra wide band transmission, and the better variant was selected based on its performance over...

This contribution documents an ultra-wide band (UWB) channel measurement performed in an in-vehicle environment for the frequency range 3-11 GHz. An emphasis is placed into an evaluation of a spatial consistency of measured channel characteristics in terms of Pearson correlation between measured channel impulse responses (CIRs). Moreover, the measu...

This paper provides results of radio channel measurement campaign carried out in the intra vehicle environment for ultra-wide band (UWB) and millimeter wave (MMW) frequency bands, namely 3–11 GHz and 55–65 GHz. In discussed frequency bands, we present and compare channel impulse responses (CIRs) for various antenna locations while considering the e...

In this paper, we present a channel estimation method based on two-dimensional signal spreading applicable to orthogonal frequency multiple access multicarrier systems. Our method exploits a spreading of a transmitted data signal as well as a pilot signal over the assigned frequency range and time period. As a spreading sequence we exploited orthog...

This contribution documents and discusses recent wideband radio channel measurements carried out in the intra-vehicle environment. Channels in the millimeter-wave (MMW) frequency band have been measured in 55-65 GHz using openended rectangular waveguides. We present a channel modeling approach based on a decomposition of spatially specific Channel...

This paper deals with the impulse interferences in modern vehicles and assesses the suitability of establishing in-vehicle wireless links replacing standard data cable bundles. According to our experiments, the standard UMTS Long Term Evolution (LTE) is highly affected by impulse noise. We compare it with a novel 2D signal spreading method exploiti...

Introduction Given the steady increase in life expectancy, an analysis of surgical outcomes in the aging population is of significant interest to vascular surgeons. The aim of our study was to assess the outcomes of abdominal aortic aneurysm repair in the elderly aged 75 plus and compare their results with people operated on at a younger age. Meth...

Background: The aim of the study was to study the frequency of cTnI release in patients undergoing an elective abdominal aortic aneurysm repair (AAA) and examine the relationship between an early perioperative myocardial injury, as detected by an increased serum levels of cTnI, and a clinical outcome (postoperative cardiac and non-cardiac complica...

Background: AAA repair is associated with high rate of mortality and morbidity. Oesophageal Doppler (OED) can offer a less invasive cost-effective tool for intraoperative monitoring of haemodynamic changes. The aim of the study was to confirm the benefits of haemodynamic optimisation in patients undergoing AAA repair using OED monitoring. We assum...

In the paper the influence of turbulent atmosphere on optical power loss in transmission channel of free space optical communication link is presented. Compared to the other, previously published works, the paper presents simulations based on very complex link model containing all important parts of an optical wireless communication system. The lin...

The paper deals with a method for simulation of transmission line (TL) models with randomly varied parameters, based on the theory of stochastic differential equations (SDE). The random changes of both excitation sources and TL model parameters can be considered. Voltage and/or current responses are represented in the form of the sample means and p...

The paper describes a multi-disciplinary design of modern communication systems. The design starts with the analysis of a system in order to define requirements on its individual components. The design exploits proper models of communication channels to adapt the systems to expected transmission conditions. Input filtering of signals both in the fr...

In an indoor optical wireless link laser beam carrying the information propagates through a room and reflects on walls and various objects. Multiple reflections and multipath distortions occur when using this link. A power budget of the indoor optical wireless link and a model of the surface reflectivity are presented in the contribution. The direc...

The result of the GALA study did not answer the question whether it is safe to perform carotid endarterectomy (CEA) under the cervical plexus block (CPB) in patients at high cardiovascular (CV) risk. The aim of the study was to compare CV stability and the frequency of cardiovascular and neurological complications in 3 groups of patients with vario...

Atmospheric phenomena such as scattering and turbulence can cause large variation in laser beam attenuation of free space optics systems. The paper deals with comparison of the atmospheric attenuation caused by both these phenomena and with comparison of the link availability affected by scattering at 850 nm and 1550 nm. The dispersive behavior of...

Cognitive radio systems are perspective solution for effective utilization of frequency spectrum. Essential feature of cognitive radio devices is scanning of certain frequency band and consequent decision making whether this band is used by primary user or not. In this paper several methods for detecting signals of analog and digital TV broadcasts...

Spectrum sensing is an essential part of the cognitive radio systems which can be the solution for radio spectrum shortage. There are various methods of the signal detection; many of them are based on the energy detector. Another group of methods is based on known detected signal parameters as the method for DVB-T signal detection described in this...