Papers by Stanislav Marchevsky
Acta electrotechnica et informatica, Mar 1, 2015
The demand on high data rate, low latency, high spectral efficiency and low power consumption cre... more The demand on high data rate, low latency, high spectral efficiency and low power consumption create an ongoing pressure on the development of communication systems. Although cellular technologies like Long-term evolution and Long-term evolution-Advanced can face many of these demanding challenges the dramatic increase of mobile data transfer in the last years give rise to design even more sophisticated methods. Multi-carrier modulation formats retain great potential to meet the requirements of the next generation 5G systems. Here, Generalized frequency division multiplexing is a promising candidate to deploy. However, as an intrinsic property of multi-carrier modulation, the high signal amplitude fluctuation can cause several degradation effects when the signal is affected by nonlinearities. Therefore, the aim of this paper is to evaluate the performance of Generalized frequency division multiplexing systems undergoing nonlinear amplification. We evaluate the bit error ratio using two model of high power amplifier, namely the Rapp and the Saleh model, respectively. The results show that the fault rate is apparently affected according to the particular high power amplifier model and its transmission parameters.
Acta Electrotechnica et Informatica, 2015
The development of modern, effective and intelligent wireless communication systems, which enable... more The development of modern, effective and intelligent wireless communication systems, which enable to provide multimedia services in high quality takes place more faster than in years before. The small frequency bandwidth gap of the 4G systems represented by Long Term Evolution (LTE) and digital broadcast system Digital Video Broadcasting-Terrestrial and the second generation denoted as T2 (DVB-T/T2) is responsible for the presence of different interference scenarios. This paper highlights the analytical background of both systems and the issue of coexistence. Moreover, computer simulations are used to evaluate the deployment of filters on the digital television receiver side as well as spectral emission mask on LTE base station in order to mitigate interference.
Electronics, 2020
This study deals with the problem of fiber-free optical communication systems—known as free space... more This study deals with the problem of fiber-free optical communication systems—known as free space optics—using received signal strength identifier (RSSI) prediction analysis for hard switching of optical fiber-free link to base radio-frequency (RF) link and back. Adverse influences affecting the atmospheric transmission channel significantly impair optical communications, therefore attention was paid to the practical design, as well as to the implementation of the monitoring device that is used to record and process weather information along a transmission path. The article contains an analysis and methodology of the solution of the high availability of the optical link. Attention was paid to the technique of hard free space optics (FSO)/RF-switching with regard to the amount of received optical power detected and its relation to the quantities influencing the optical communication line. For this purpose, selected methods of machine learning were used, which serve to predict the rec...
Our paper presents several median based models of filters designated for solution of the problem ... more Our paper presents several median based models of filters designated for solution of the problem mentioned in head-line. In the motion picture industry, both, “dirt and sparkle” often appear. These are flashes, i.e. more than one pixel, of totally different brightness, unrelated to the surrounding area of the frame, and also unrelated to adjacent frames. To restore such image sequences, it is possible to use median based multilevel filters, which yield to quite good results and are computationally modest. To avoid useless affect the other uncorrupted pixels, these filters have to cooperate with operation of missing data detection, which is also briefly described in this submission. The results are declared by representative frames as well as by numeric error criteria.
Journal of Electrical Engineering, 2013
One of the biggest challenges of communication networks is the video transmission in real time. I... more One of the biggest challenges of communication networks is the video transmission in real time. It requires high demands on the available network capacity and transport mechanisms. Availability of smart mobile devices with batteries, which keep the terminal working for several hours, caused an increased interest in the research of the deployment of video transmission in wireless transmission systems. The presented paper deals with the transmission of video encoded with H.264/AVC (Advanced Video Coding) video coding standard through wireless local area network (WLAN) using the programming environment OPNET Modeller (OM). The test network studied in this work was prepared by combining real and simulated networks, which allows interesting possibilities when working with the OM tools. Such an approach to working with OM allows a detailed video streaming analysis, because the video output was noticeably not only in the form of statistics, but we can see the real impact of transmission failures. Using the OM simulation environment allows to design the transmission systems, which would be difficult to establish in laboratory conditions. K e y w o r d s: H.264/AVC, OPNET modeller, system-in-the-loop, video transmission, wireless local area network
Video transmitted over unreliable environment, such as wireless channel or in generally any netwo... more Video transmitted over unreliable environment, such as wireless channel or in generally any network with unreliable transport protocol, is facing the losses of video packets due to network congestion and different kind of noises. The problem is becoming more important using highly effective video codecs. Visual quality degradation could propagate into subsequent frames due to redundancy elimination in order to obtain high compression ratio. Since the video stream transmission in real time is limited by transmission channel delay, it is not possible to retransmit all faulty or lost packets. It is therefore inevitable to conceal these defects. To reduce the undesirable effects of information losses, the lost data is usually estimated from the received data, which is generally known as error concealment problem. This paper discusses packet loss modeling in order to simulate losses during video transmission, packet losses analysis and their impacts on the motion vectors losses.
This article explores cloud-based data processing object detection for future anti-collision syst... more This article explores cloud-based data processing object detection for future anti-collision system and georeferencing. At present, data processing from Unmanned Aerial Vehicles (UAVs) is based, in most cases, on sequential image acquisition and subsequent processing, but there is a demand for real-time resolution. Real-time data processing can be beneficial to track changes accurately. The help of real-time kinematic sparse data generation is a possibility for new remote sensing applications. Sensors of light-weight and low-cost UAVs provide the opportunity to create target data in real-time.
S rozvojom nových komunikačných technológií, napr. systémov pre videotelefóny, videokonferenčných... more S rozvojom nových komunikačných technológií, napr. systémov pre videotelefóny, videokonferenčných systémov, HDTV, internetu a digitálnej televízie, vyvstala aj požiadavka číslicového spracovania farebných obrazov. Vzhľadom na skutočnosť, že farebné obrazy predstavujú vektorovo-hodnotové signály, dôraz pri spracovaní sa kladie na použitie vektorových techník. V prípade odstraňovania šumu v obrazoch sa tento problém dotýka vektorových filtrov. Z týchto dôvodov je témou tohto článku prehľad najčastejšie používaných vektorových filtrov pre potláčanie impulzového šumu vo farebných obrazoch.
2008 50th International Symposium Elmar, Sep 1, 2008
Above-barrier cross sections of α-active heavy reaction products, as well as fission, were measur... more Above-barrier cross sections of α-active heavy reaction products, as well as fission, were measured for the reactions of 10,11 B with 209 Bi. Detailed analysis showed that the heavy products include components from incomplete fusion as well as complete fusion (CF), but fission originates almost exclusively from CF. Compared with fusion calculations without breakup, the CF cross sections are suppressed by 15% for 10 B and 7% for 11 B. A consistent and systematic variation of the suppression of CF for reactions of the weakly bound nuclei 6,7 Li, 9 Be, 10,11 B on targets of 208 Pb and 209 Bi is found as a function of the breakup threshold energy.
Elektronické prvky : Prednášky
ABSTRACT
The LMS-based adaptive order-statistic filters are presented in this paper. The adaptive Ll-filte... more The LMS-based adaptive order-statistic filters are presented in this paper. The adaptive Ll-filters as extension of the adaptive L-filter for two-dimensional filtering of noisy greyscale images is studied too. Their adaptation properties are studied by three types of noise, the additive white Gaussian noise, the impulsive noise or both, respectively. Moreover, the impulsive noise has the fixed noise value (Salt & Pepper noise). The problem of pixel value multiplicity and determination its position in the ordered input vector for adaptive Ll-filter is shown in this article. The two types of images with different of image complexity are used to demonstration of the power of time-spatial ordering.
2008 18th International Conference Radioelektronika, 2008
Blind detection is one of the most perspective techniques in signal processing theory. In this pa... more Blind detection is one of the most perspective techniques in signal processing theory. In this paper we describe blind detector based on the linearly constrained constant modulus algorithm (LCCMA). Simulations are oriented on multi-carrier code division multiple access (MC-CDMA) signals when turbo codes are used for error corection of transmitted images. We had investigated the system bit error rate (BER) performance in 3-states channel enlarged with a complex AWGN (aditive white Gauss noise) noise. The channel model is assigned for Land mobile satellite (LMS) communications. The application of turbo coding strengthens the system ability to cope with multi-path fading and multi-access interference (MAI) significantly.
Signal Processing Tool Based on Invertible Rapid Transform
2007 8th International Conference on Telecommunications in Modern Satellite, Cable and Broadcasting Services, 2007
ABSTRACT The proposed paper deals with the signal processing using Invertible Rapid Transform (IR... more ABSTRACT The proposed paper deals with the signal processing using Invertible Rapid Transform (IRT). A software tool for signal and image processing using IRT is presented.
MSF-MUD and BA-MUD receivers: principles and comparison
Second IEEE International Conference on Computational Cybernetics, 2004. ICCC 2004.
Microstatistic multi-user detection receiver (MSF-MUD) and blind adaptive multi-user receiver (BA... more Microstatistic multi-user detection receiver (MSF-MUD) and blind adaptive multi-user receiver (BA-MUD) are two different minimum mean square error suboptimum receivers for code division multiple access (CDMA) transmission systems. The BA-MUD belongs to well-know receivers. On the other hand, the MSF-MUD has been described only in several papers. The properties of the MSF-MUD have not been yet compared with that of the BA-MUD. With regard to that fact, we would like to describe the basic structure of the MSF-MUD and BA-MUD and to compare their basic performance properties in this paper. Because the MSF-MUD properties have not been described extensively, we believe that this comparison is useful contribution to MUD theory
Error resilience tools in the MPEG-4 and H.264 video coding standards
2008 18th International Conference Radioelektronika, 2008
ABSTRACT In this paper we introduce error resilience tools which are used by MPEG-4 and H. 264 vi... more ABSTRACT In this paper we introduce error resilience tools which are used by MPEG-4 and H. 264 video coding standards. MPEG-4 as well as H.264 offers error resilience tools which were implemented by older video coding standards, but they also introduce new tools and improved efficiency of previously used tools. This paper offers only brief review of them, but it focuses on their most important characteristics.
Image Transmission over the 3-states Channel Using MOE Blind Algorithm
2007 17th International Conference Radioelektronika, 2007
In this paper, we describe a problem of mitigating a multiple-access interference (MAI) and a cha... more In this paper, we describe a problem of mitigating a multiple-access interference (MAI) and a channel disturbance in DS-CDMA technology. The receiver is based on a blind algorithm, which does not need any training sequence, or any information about the channel. Our simulations are oriented on a land mobile communications, where the channel is changing through the time. Proposed channel consists of three states. The comparison of effectiveness between the blind MOE algorithm and conventional detection using computer simulations is demonstrated and the experimental results of image transmission over 3-states channel using blind detection are presented.
Acta Electrotechnica et …, 2009
This paper presents some of current trends of the development of next generation satellite system... more This paper presents some of current trends of the development of next generation satellite systems as an access network within NGN converged networks by analyzing satellite e-learning (e-consulting and e-collaborative work) aspects. Attention is aimed on the interactive (two-way) broadband satellite services based on IP. This paper provides the non-specialist reader with an overview of the opportunities offered by recent developments in satellite technology for education. It includes an overview of current and expected services. It also provides a general guide for those interested in setting up and using such systems in an educational context in terms of the way in which they can and should be deployed.
2-stage Blind Receiver Based on the CM algorithm for MC-CDMA Signals Detection over the 3-states Channel Model
2007 14th International Workshop on Systems, Signals and Image Processing and 6th EURASIP Conference focused on Speech and Image Processing, Multimedia Communications and Services, 2007
ABSTRACT In this paper we describe 2-stage blind detector, of which the second stage is based on ... more ABSTRACT In this paper we describe 2-stage blind detector, of which the second stage is based on the constant modulus algorithm (CMA). Simulations are oriented on MC-CDMA signals and the image transmission over 3-states channel enlarged with a complex AWGN noise. The channel model is assigned for Land mobile satellite communications.
Communications - Scientific letters of the University of Zilina
In recent years, many linear filters have been replaced by nonlinear filters, especially in case ... more In recent years, many linear filters have been replaced by nonlinear filters, especially in case of impulse noise distorting. Stack filters, the class of non-linear filters are very interesting for easy hardware realisation and threshold decomposition property. The development of digital HDTV gives technological push in this area. Various of very efficient order-statistics filters such as median or LUM smoother are useful in many applications. In addition, these filters can be realised as stack filters. This paper gives a short review of the stack filter class.
Communications - Scientific letters of the University of Zilina
The development of modern communication technologies such as video phones, video conferencing sys... more The development of modern communication technologies such as video phones, video conferencing systems, HDTV, Internet and digital television requires color image digital processing. Concerning the fact that color images represents vector-valued signals, the use of vector techniques is demanded. In the case of noise removing the problem is related with vector filters. On that reason, this paper is focused on reviewing the most frequently used vector filters for impulse noise suppression in color images.
Uploads
Papers by Stanislav Marchevsky