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Verification of Properties of WiFi IEEE 802.11n
Alexa, Jan ; Miloš, Jiří (referee) ; Kuder, Zenon (advisor)
This bachelor thesis deals with wireless systems of IEEE 802.11 standards. This thesis explains the fundamental terms and principles, which are relating to digital wireless systems. This thesis is structured into four thematic units. The first chapter discusses an introducing with Wi-Fi standard – IEEE 802.11 in general. Second part contains a deeper focus on modern standards 'n' and 'ac', showing the main differences and innovation compared to older standards 'b', 'g', 'a'. Further in this part of the thesis is described using of MIMO technology. The third chapter contains an analysis and description of the application, which is part of the thesis. The fourth part is detailed focused on to the design of laboratory tasks for teaching at the undergraduate level, which demonstrates the use of MIMO technology.
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Modeling and simulation of PLC in Network Simulator-3 for Smart Metering
Petrůj, Jakub ; Sláčik, Ján (referee) ; Mlýnek, Petr (advisor)
The diploma thesis deals with analysis and modeling of power line communication using NS-3. The introduction part summarizes basic information about PLC technology, distribution grids, and broadband standards. This is followed by the analysis of the transmission line and modulation method. Furthermore, the simulation tool and possibilities of its extension are described. The influence of different cross-section and type of line on channel capacity is examined in the practical part of this paper. The influence of repeaters on bitrate is examined as well. The medium-voltage line was implemented and further scenarios dealing with bitrate or optimal level of noise. The focus of the last part is to find the repeaters on the path and to determine the capacity and bitrate on the path of the large topology.
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Analysis of the effect of delay and window size on TCP connection efficiency
Kavický, Martin ; Komosný, Dan (referee) ; Molnár, Karol (advisor)
Content of master’s thesis is description field of Sliding window and it’s expansion algorithms, witch are Slow start, Congestion avoidance, Fast Retransmit and Fast Recovery algorithm. Thereinafter is described creation of model in Opnet Modeler’s simulation area. In this simulation area was analyzed reactions of average transfer speed onto variance of data size, lost ratio, latency in short and long time slot and variance of receiver’s buffer size. In last section of this document is method design witch makes it possible of transfer speed control through the use of receiver’s buffer size dynamic setting.
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Data logger for serial communication lines
Jankech, Tomáš ; Šebesta, Jiří (referee) ; Dušek, Martin (advisor)
The aim of bachelor’s thesis is the realization of data logger for serial communication lines. This paper describes basic concepts of serial communication and looks more deeply into RS232 and RS485 serial communications standards. It describes usual methods of data recording and their application in practice. Data logger’s block diagram is described in detail for each of its parts. Their descriptions contain an overview of circuits, which allows realization of individual blocks and circuit diagram of selected circuit. Following chapters describes design of printed circuit board, control application for PC and firmware for the microcontroller.
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Modulations in PLC systems
Procházka, Vít ; Kouřil, Jiří (referee) ; Krajsa, Ondřej (advisor)
The bachelor thesis describes principles and methods of Powerline Communications, practical usage possibilities both in industrial applications but mainly in broadband systems that may represent promising competition to conventional broadband access, e. g. xDSL connections without the need of new wiring, WIFI etc. The thesis also focuses on problems that can occur in the communication channel from the view of electromagnetic compatibility and assorted interferences. The 50 Hz frequency electric network (60 Hz in the USA) was not designed for data signal transmission, problems may arise mainly at higher frequencies and broadband communication. It is necessary to implement methods which enable transfer of information signal through a communication channel with minimalization of problems such as interference, cable attenuation, electromagnetic compatibility, bit error rate (BER), etc. Furthermore, currently used modulation principles and their characteristics are described, such as spread spectrum modulation DSSS, FHSS, traditional OFDM, alternative modulations FMT and DWMT with filter banks. The last chapter of the bachelor thesis features models of particular modulations created in the Matlab-Simulink program and the conclusion presents advantages and disadvantages of their implementation in PLC systems.
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Anonymous communication in Internet environment
Pajtinová, Mária ; Malina, Lukáš (referee) ; Hajný, Jan (advisor)
Master´s thesis focuses on certain possibilities of how user can anonymously commununicate through the Internet. There are described following anonymous programs: TOR, JAP, I2P and CyberGhost, which allow user to hide his own identity to other IP address. Subsequently, measurements from different technologies are made by anonymous program TOR for calculate transmission speed.
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Extension of optical fiber transmission system
Horský, Tomáš ; Tomašov, Adrián (referee) ; Dejdar, Petr (advisor)
The diploma thesis describes the elaboration of a program for the simulation of an optical transmission path. The work introduces the basic parameters of optical transmission, such as attenuation, dispersion and bandwidth. Furthermore, the techniques of line code and error detection are described in the work, especially a cyclic redundancy sum. The key parameter of this thesis is dispersion of the optical signal. The work includes the characteristics of the eye diagram and its analysis. The resulting program can also be used to measure the real transmission route and its parameters.
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Measurement of transfer speeds and delays in computer networks
Bárdossy, Adrián ; Kubánková, Anna (referee) ; Jeřábek, Jan (advisor)
Bachelor thesis is interested in measurement of transfer rate and latency in computer networks. In the first part of thesis is defined, which motodics of measurement we know, various RFC and their specifications, also various parameters about measurement in computer networks like bit rate, capacity of channel, latency. In the second part are prepared users interfaces and softwares for applying the measurement of thesd parameters. In the last part is application of these softwares and creating and testing methodic of network measurement.
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Performance and security analysis of Wireguard technology
Varga, Oliver ; Holasová, Eva (referee) ; Krajsa, Ondřej (advisor)
This thesis deals with the description of WireGuard virtual private networks technology, its comparison with the technologies IPsec and OpenVPN based on the encrpytion algorithms they use to ensure security and also compares their technical parameters such as latency, jitter and transfer speeds. The work includes a description of the WireGuard technology, a comparison of the mentioned technologies and finally the results of the measurements of their technical parameters. The methodology chosen by us for testing the parameters, the hardware used to obtain the results and the network topology are also described. Finally, the results obtained from the tests are compared.
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Wireless communication link analyzer
Dostálek, Jakub ; Burian, František (referee) ; Jílek, Tomáš (advisor)
The aim of this bachelor thesis is to design and implement a wireless communication analyzer in mobile robotics, using IPv4 protocol and Ethernet interface and to create correctly selected and expressed characteristics from the measured data, according to which the wireless communication channel can be further optimized for the best data transmission. To meet these requirements, a brief search of existing solutions was performed, their applicability was discussed and important parameters of the wireless transmission channel were defined, which will form the given characteristics. Furthermore, the actual design and implementation of a wireless communication link analyzer for previously specified required parameters, verification of its functionality on the transmission link with known parameters and automation of measurement and data evaluation was performed.
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