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Návrh a realizace bezdrátového přenosového systému na USRP
Vaclík, Michal ; Mlýnek, Petr (oponent) ; Krajsa, Ondřej (vedoucí práce)
Bakalářská práce se zabývá návrhem modulárního přenosového systému na platformě softwarově definovaného rádia. Je zde využito kitů USRP1, které jsou řízeny skripty vytvořenými v software GNU Radio Companion. Výstupem práce jsou vytvořené skripty v jazyce Python, kterými lze ovlivňovat modulační schéma, kódování a přenosovou rychlost bezdrátového komunikačního systému. Závěr práce je věnován zhodnocení přenosových vlastností a nedostatků navrženého řešení.
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Air Traffic Simulation with HackRF One
Mikan, Lukáš ; Dvořák, Vojtěch (oponent) ; Šťáva, Martin (vedoucí práce)
This work deals with air traffic simulation in the context of a multilateration surveillance system. The technique of multilateration calculates aircraft position at the intersection of hyperboloids, obtained from the differences in time of arrival of transponder messages to multiple receivers at known coordinates. By substituting an SDR module for each receiving antenna, air traffic can be simulated with the use of made-up ADS-B messages which get sent to the various antenna ports with proper timing. This thesis uses the HackRF One SDR that had both its hardware and firmware modified in order to achieve tightly synchronized transmissions from potentially any number of interconnected HackRF units. The modifications described herein ensure an identical sampling clock, both frequency- and phase-wise, across all units, as well as simultaneous triggering of transmissions. In the second part of the thesis, an algorithmic solution is presented for assembling fictional air scenarios with arbitrary number of flights and receiving stations. The output is a set of data streams suitable to be transmitted through synchronized HackRF's. Each stream represents a specific vantage point, a specific antenna, and contains precisely timed ADS-B messages, encoded using pulse-position modulation and converted into IQ samples. The complete solution can be used to validate the functioning of a real multilateration system, such as the MSS made by ERA, a.s.
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Signálová analýza LoRa s využitím SDR
Jeřábek, Ondřej ; Fedra, Zbyněk (oponent) ; Povalač, Aleš (vedoucí práce)
Tato práce se zabývá zkoumáním bezdrátové komunikace pomocí komunikačního, long range protokolu LoRa a její MAC vrstvy LoRaWAN. Analýza je především zaměřena na detekci LoRa paketu pomocí softwarově definovaného rádia, bezdrátový provoz a informace volně dostupné z MAC vrstvy LoRaWAN získané pomocí odposlechu signálu z okolních zařízení. Součást práce tvoří návrh funkčního demonstračního zařízení využívajícího některého z komerčně dostupných modulů spolu se snifferem zprostředkující paralelní příjem z více frekvenčních kanálů.
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Spatial Identification Methods and Systems for RFID Tags
Povalač, Aleš ; Carvalho, Nuno Miguel Gonçalves Borges de (oponent) ; Polívka,, Milan (oponent) ; Šebesta, Jiří (vedoucí práce)
The doctoral thesis is focused on methods and systems for ranging and localization of RFID tags operating in the UHF band. It begins with a description of the state of the art in the field of RFID positioning with short extension to the area of modeling and prototyping of such systems. After a brief specification of dissertation objectives, the thesis overviews the theory of degenerate channel modeling for RFID communication. Details are given about phase-based ranging and direction of arrival finding methods. Several antenna placement scenarios are proposed for localization purposes. The degenerate channel models are simulated in MATLAB. A significant part of the thesis is devoted to software defined radio (SDR) concept and its adaptation for UHF RFID operation, as it has its specialties which make the usage of standard SDR test equipment very disputable. Transmit carrier leakage into receiver path and requirements on local oscillator signals for mixing are discussed. The development of three experimental prototypes is also presented there: experimental interrogator EXIN-1, measurement system based on Ettus USRP platform, and antenna switching matrix for an emulation of SIMO system. The final part is focused on testing and evaluation of described positioning techniques based on complex backscatter channel transfer function measurement. Both narrowband/wideband ranging and direction of arrival methods are validated. Finally, both proposed antenna placement scenarios are evaluated with real-world measurements.
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Telemetrický archiv družic
Vorálek, Jan ; Povalač, Aleš (oponent) ; Urbanec, Tomáš (vedoucí práce)
Práce se zabývá návrhem archivu vysílaných telemetrických dat družic PSAT, PSAT-2 a BRICSat, která je třeba získat z SDR IQ záznamů. Součástí práce je teoretický popis Dopplerova jevu a struktury vysílaných telemetrických dat. Dále je zde popsán návrh programu pro odstranění Dopplerova jevu, demodulaci a dekódování těchto záznamů a uložení dat do telemetrického archivu. Práce se dále zabývá analýzou získaných dat.
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Music Source Separation
Holík, Viliam ; Veselý, Karel (oponent) ; Mošner, Ladislav (vedoucí práce)
Neural networks are used for the problem of music source separation from recordings. One such network is Conv-TasNet. The aim of the work is to experiment with the already existing implementation of this network for the purpose of potential improvement. The models were trained on the MUSDB18 dataset. It was successively experimented with the change of the network structure, transforming signals from the time domain to the frequency domain for the purpose of calculating the loss function, replacing different loss functions with the original one, finding the optimal learning rate for each loss function and gradually decreasing the learning rate during the learning process. The best experiments according to the SDR metric were training with loss functions L1 and logarithmic L2 in the time domain with a higher initial learning rate with its gradual decrease during the learning process. In a relative comparison of the best models to the baseline, it is more than 2.5% improvement.
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Radio spectrum analysis with a focus on WiFi bands using software-defined radio
Pospisil, J. ; Fujdiak, R.
This paper deals with the issue of radio spectrum analysis focused on WiFi (Wireless Fidelity) bands. The aim of the article is to approach the issue of capturing the radio spectrum and its visualization. Ways of approaching the solution of the problem are discussed, and on the basis of this comparison, attention is further focused on the use of SDR (Software Defined Radio). This device creates digitalized samples of captured radio signals and forwards them via USB to a computer, where the samples are further processed and visualized. The result is a functional program capable of visualizing this data in the form of a waterfall spectrogram. These results can also be additionally used for advanced machine analysis.
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Software-defined radio OFDM frame generation according to IEEE 802.22
Honek, Marek ; Gazda, Juraj (oponent) ; Maršálek, Roman (vedoucí práce)
This thesis proposes a new radio transmission protocol AWRAN for access to the amateur radio network HAMNET that does not require LOS to the access point. Furthermore, the thesis documents and discusses the prototypical implementation of simplified frames of this protocol on SDR and the test apparatus used for this purpose. The first chapter introduces the IEEE 802.22 WRAN standard on which AWRAN is based. Terms such as OFDM and OFDMA are described, as well as their advantages and applications. There are described the modulation techniques PSK and QAM, channel coding for error detection and correction, and the sources of these errors. The second chapter gives a detailed description of the parameters of the proposed AWRAN protocol. OFDM parameters, frame and superframe structures are described. The method of co-existence of multiple AWRAN cells and the exact form of the fourteen control messages that allow efficient allocation of bandwidth resources among up to four base stations and up to 63 users connected to each of these stations are described. The third section describes the structure of the simplified frame that was implemented on the RPX-100 testbed. It also describes the apparatus itself and its basic hardware building blocks as well as the software library that was used to implement the simplified frame. This chapter also describes the prepared test link and the theoretical calculation of the attenuation of this link. The fourth chapter deals with the programs that were developed as part of this work. Two of them were done for a first introduction to the hardware and software libraries. Another program serves as a generator of the previously described simplified frames, which are sent using SDR. The same program could be used as well as the receiver of these frames. The last program prepared performs a simulation of the wireless transmission using a mathematical model of the channel. It calculates the dependence of BER on SNR for the simulated transmission. The last section lists the functions that were defined and used in programs from the previous section.
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Prototype of Intrusion Solution for Mobile Networks
Kamenský, Timotej ; Letavay, Viliam (oponent) ; Veselý, Vladimír (vedoucí práce)
As the mobile networks rise, the importance of their security rises too. The vulnerabilities of the mobile protocols on L1-L3 are easily misused. Using a small and relatively cheap Software Defined Radio, it is possible to implement a variety of attacks aiming at mobile networks. Goal of this work is to create an intrusion tool, implementing the available attacks. These include jamming of the connection, service downgrade, Denial of Service, Location tracking, IMSI catcher.
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Implementation Of Fsk Modulated Signal Receiver Using Software Defined Radio
Pospisil, Jan
This paper discusses recent trends in a wireless communication system using Software DefinedRadio (SDR). SDR, in this case, the BladeRF 2.0, in combination with a software layer writtenin the Python language, is taking care of signal demodulation. BladeRF 2.0 is a device that providesa powerful waveform development platform expected by industry professionals. The BladeRF 2.0 isused to design a Frequency Shift Keying (FSK) receiver (in the form of binary data). As a transmitter,we created a custom-designed end-device using CC1101 RF (Radio Frequency) module. The scenarioin the current experiment is that the SDR acts as a receiver for the transmitting end-node.
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