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Fading channel hardware simulator
Pirochta, Pavel ; Kováč, Michal (referee) ; Maršálek, Roman (advisor)
Fading channel is a communication channel that experiences different interference and fading due to multi-path signal propagation. The fading channel is designed by the finite impulse response filter with the time-varying impulse characteristic. The realisation of this filtr is based on the TDL (Tapped Delay Line) model, which simulate signal delay and signal attenuation in each branch. The aim of this thesis is to create the VHDL design of selected fading channel simulator and its description for hardware implementation into the FPGA.
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Evaluation of Selected Software Tools for Modeling the Leakage of Hazardous Substances in Accidents in the Chemical Industry
Hrušková, Veronika ; Martincová, Jana Victoria (referee) ; Adamec, Vladimír (advisor)
The thesis is aimed at the modeling of releases of hazardous substances to the designated software tools. The work consists of three parts. The first part is theoretical, which deals with hazardous substances and their legislation, accidents in industry, physical models of leakage and dispersion of hazardous substances and factors influencing their spread in the air and finally software tools. The second part, experimental, describes some software tools and their subsequent modeling. The third part is devoted to the results of modeling and analysis of selected software tools. The aim of the thesis is to analyze selected software tools for modeling the release of hazardous substances, to compare their explanatory power and potential use.
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Simulation of multipah propagation of multistate modulations
Polák, Ladislav ; Pust, Radim (referee) ; Šebela, Radek (advisor)
The diploma thesis Simulation of Multipath Propagation of Multistate Modulations is focused on the development of an appropriate algorithm in MATLAB environment, which is capable to simulate the impact of the multipath propagation on received signal (error rate) on the basis of given parameters of the transmission channels. Mechanisms and characteristics of the wave propagation in communication environment, types of digital modulations and their most important parameters are described in the first part of this thesis. The second part is focused on the simulation itself. Created GUI (Graphical User Interface) is able to display constellation diagrams of transmitted and received signals, as well as their bit error rate. It is also possible to compare these data with the data of signal, which is passed by a non-fading channel.
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Wireless transmission interference modeling (AWGN, Rayleigh, Rice fading channels)
Hloušek, Tomáš ; Gleissner, Filip (referee) ; Mikulka, Jan (advisor)
This thesis describes and models wirelesss transmission intereferences in real communication channels. A signal received on a fading channel is subjected to a multiplicative distortion and to the usual additive noise. Real channel adds to the signal noise and fadings. Gaussian noise is a result of channel awgn. Fadings is implicated by multipath propagation of signal in Rayleigh and Rician channels. Main goal of this project is to program BERsolve, which is created in tool GUIDE in Matlab. User program BERsolve makes it possible to analyse bit error rate and symbol error rate for some types of channel models, which are defined by standard COST207. BERsolve offers some other functions i.e. display time behaviour, constellation diagram and spectrum. This program provides us with an overview representation of problem by multipath interferences in communication channels.
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Channel estimation in CDMA systems
Kadlec, Petr ; Prokopec, Jan (referee) ; Kejík, Petr (advisor)
The subject of this work deals with the problem of channel estimation for CDMA systems. This method of multiple access when individual users share the same full bandwidth simultaneously and are differentiated with any of pseudorandom sequences, is now the most perspective method. That is proved by its wide implementation in mobile networks of the third generation and higher systems. This work describes basic theory principles of spread spectrum, above all DS-CDMA (Direct Sequence-CDMA) and furthermore some phenomena of radio wireless channel that affect changes in transmitted signal in its way from transmitter to receiver. Terms of fading, multipath propagation, loss, refraction, scattering of the wave and Rice and Rayleigh probability density functions are mentioned. The third chapter deals with yet known and used capabilities of channel estimation. Differences, advantages and disadvantages of so-called blind estimation or training-based estimation are discussed. Two algorithms: LS method and sliding correlator are analyzed in more detail. There is also description of their simulations in Matlab and some results of these simulations are discussed. The last chapter deals with comparison of main characteristics and achievable accuracy of wireless channel impulse response estimation by both methods, and their possible utilization in real live.
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Hardware MISO Emulator for Fading Channels
Rez, Jan ; Pítra,, Kamil (referee) ; Šebesta, Jiří (advisor)
This thesis is devoted to study the possibility of solving a hardware MISO emulator for fading channels and design of experimental device. The theoretical part starts with the theory of propagation of electromagnetic waves in a different types of environment, follows the principles and phenomena describing the radiocommunication channels and gradually gets up to specific channel models used for planning radio links. The actual design study of emulator is based on theoretical knowledge mentioned in this thesis. The basic principle of each channel model and thus so the emulator for fading channels is Tapped Delay Line model. From the point of view of the peripheral emulator solutions are designed with two topology circuits, parallel and serial-parallel. Emulator control method, mechanical arrangement, selection of topology circuit, components selection, desing of the PCB and software design is also analyzed. The results of this thesis is prototype production of experimental device and final discussion about achieved requirements and tasks.
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Simulation of the Transmission Channels for the Digital Television DVB-T/H
Kučera, Jan ; Ulovec,, Karel (referee) ; Kratochvíl, Tomáš (advisor)
This thesis focuses on analysis, classification, simulation and assessment of the signal fading in the scope of terrestrial digital television reception. This is a phenomenon associated with signal multipath propagation caused by the reflection, dispersion and diffraction of electromagnetic waves in interaction with relief and artificial obstacles. Wave propagation issues in a specific landscape are not the central theme of this project. Signal transmission between the transmitter and receiver is defined by channel profile models. Attention is directed not only to static reception but also to portable and mobile reception. Simulation of this phenomenon takes place in the software environment of MATLAB. In the framework of this project program fundament was created which allows simulate the signal processing across the entire communication chain of television broadcasting, including its transmitting and receiving parts.
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Optimization of ultrasonic leak detector of pneumatic system
Macků, Ondřej ; Mazal, Pavel (referee) ; Vlašic, František (advisor)
The thesis deals with design and optimization of exchangeable modules for localization of air distributable ultrasound in concept of ultrasound probe design. Several series of these modules were manufactured using the technology of rapid prototyping and tested on artificially created source of air leak. Based on these verification experiments two types covering wide use for identification of pneumatic systems leaks were selected and modified. These two types are long range module for more accurate and expended reach of the leak detection and focusing attachment for narrowing the received range of scanning module and elimination of surrounding ultrasound. Part of the thesis is also analysis of the acoustic signal processed by modern acoustic emission analysers which allow besides standard parameters recording also continuous sampling up to 10 MHz and design solution for attachment of add-on modules to the detector. The thesis is beneficial for raising awareness of leak measurements, prototype manufacturing by using the 3D printing and designing and manufacturing of modules.
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Signal propagation in mobile communication systems
Julínek, Pavel ; Hanus, Stanislav (referee) ; Klozar, Lukáš (advisor)
The aim of this thesis is to describe the basic principles and function of signal propagation in mobile communication systems. Closer look is taken at GSM and UMTS communication systems. The thesis deals especially with the problem of path losses, which occurs between transmitter and receiver. Possible propagation scenarios for cellular network are theoretically described. Also the propagation models for outdoor and indoor path loss prediction are described and simulated. The developed program estimates path loss and graphically represents the results of simulation for various model parameters, environments and scenarios.
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