|
|
FTTH deployment in local networks
Horníček, Lukáš ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
The master’s thesis is focused on the theoretical and practical issues of optical access networks. The first chapter of the thesis deals with the concept of the access networks known as FTTx. The second and third chapters focus on the principles and standardization of the active optical network AON P2P and the passive optical network TDM PON. The fourth chapter of the thesis focuses on the network WDM PON, wavelength multiplexes, solution concept and the LG-Ericsson EA 1100 platform. The fifth chapter of the thesis deals with the infrastructure of the optical paths for optical access networks. The sixth chapter of the thesis presents custom design of the headend for reception, processing and distribution of television broadcasting. Two custom access network solutions (AON P2P and WDM PON) for the town Bystřice nad Pernštejnem are presented in the seventh chapter. Case studies include the design of the optical paths infrastructure, central office infrastructure, end-user infrastructure, CAPEX/OPEX economic analysis and basic simulation in OptSim.
|
|
|
Optimization and parameter measurement of PON network FTTX
Černý, Michal ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
Práce rozebírá současný vývoj na poli pasivních optických sítí a jednotlivé generace přenosových standardů. Podrobněji se zabývá parametry ODN, metodami jejich měření a volbou potřebných měření v praxi. Hlavní část práce je zaměřena na měření pasivního WDM prvku, kde je provedena analýza vstupů a výstupů, měření vložného útlumu a přelechů podle ORL na provozních vlnových délkách.
|
|
|
Optical cables in modern data centres
Hejtmánek, Ondřej ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
The essence of this study was to evaluate the issue of fiber optic and data cables in modern data centers. To compare and evaluate optimal design parameters were chosen as follows: Performance, reliability, installation time, flexibility, weight and size, requirements maintenance and training and the total price. The introductory chapters describes structure of the data center and network bases and storage technologies used in data centers. Particularly a local area network Ethernet and storage technology, DAS, SAN and SAS. Followed by a metallic and fiber optic cabling. For metallic cabling are used primarily PiMF cables. The fiber optic cabling emphasis was placed on multimode fiber OM3 and OM4. The main point of this study was to compare three types of installation metallic and three types of fiber optic cabling. MRJ-21 solution, pre-terminated system and standard installation of the so-called notch technique for metallic cables. For optical cabling has been chosen MPO solution, pre-terminated system and standard installation by welding fibers. In the end were compared and evaluated various solutions. The main focus was placed on the parameters of performance, reliability and installation time. The optical systems were rated the best solution MPO and preterminated system. Results were similar for the metallic cabling, where most of the parameters of the solution satisfies MRJ-21 followed by pre-terminated system. Standard installation for both types of cables in data centers too has not worked. All types of installations have been tested in practice and measured at different times during install.
|
|
|
Cell - Phone Effects on Human Health
Pieniažek, Ireneusz ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
This bachelor’s thesis is dealing with the influence of cell phones on man. First part is focused on the introduction to the problems of cell phone communication. There are described the frequencies and wave lengths, which the cell phones use. Here is also described the principle of cell phones functioning. Second part is devoted to influence of the cell phones on the human body. It is discussing the electromagnetic compatibility of the biological systems and describing the electromagnetic field occurring in cell phone communications. There are also described the thermal effects of the cell phones and this chapter further discusses the hypothesis about the non-thermal effects of the cell phones. There is a description of mechanism of influence of radio waves. This part also describes the possible health hazards resulting from the use of cell phones and the problem of relationship between the occurrence of cancer and the use of cell phones. There are mentioned other ecological problems connected with cell telephony. Third part is focused on the SAR measurement (specific absorption rate) of the cell phone. Here we can find the definition of SAR. It describes the tested apparatuses, the procedure of measurement and measured values for GSM 900, GSM 1800 and W-CDMA 2000 standards. Tested apparatus in this case is Samsung SGH-Z140V. We can find here technical engineering solutions, which are aimed to minimize the specific absorbing power absorbed by human body during the use of apparatus.
|
|
|
Localization in Wireless Energy-Constrained Networks
Morávek, Patrik ; Vozňák, Miroslav (referee) ; Křepelka, Václav (referee) ; Komosný, Dan (advisor)
Tato disertační práce se věnuje lokalizaci v bezdrátových sítích se zaměřením na odhad vzdálenosti. Lokalizace je v bezdrátových sítích s mobilními ale i statickými uzly důležitým procesem, neboť znalost pozice uzlů může být během provozu sítě dále s výhodou využita. V práci je prezentována nová metoda odhadu vzdálenosti na základě měření síly přijatého signálu. Navržená metoda je postavena tak, aby s co nejnižšími energetickými náklady dosáhla požadovaného stupně přesnosti i ve značně odlišných rádiových podmínkách. Před návrhem vlastní metody byla provedena experimentální analýza spotřeby anergie a šíření signálu s jeho využitím pro lokalizační účely. Na základě provedené analýzy byla navržena nová metoda (Adaptabilní energeticky nenáročná metoda odhadu vzdálenosti), která byla následně ověřena v simulátoru a experimentální síti za reálných podmínek.
|
|
|
Effect of optical connectors quality on transmission
Bernkopf, Miroslav ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
This diploma thesis deals with optic fiber connectors and their influence on transmissions realized via fiber optics. Optical fibers and lightguides play the key role in telecommunications because of constant demands of higher bandwidth and data rates. Original metalic wires do not meet market requirements and so the fiber optics are more and more being used. There are various types of fibers and there are also many ways of connections. This work deals with demountable way of connection – optical connectors, which have the biggest influence on a total attenuation and route length. Connector has to meet various requirements such as cleannes, quality, mechanical construction and ferrule polishing.
|
|
|
Parameters of FTTx Networks
Münster, Petr ; Křepelka, Václav (referee) ; Vlček, Čestmír (referee) ; Filka, Miloslav (advisor)
This thesis examines parameters of FTTx networks and possibilities for increases in limit values of some selected parameters. The first and second chapters describe the necessary theory for understanding the outcomes presented in the rest part of the work. In the practical part of this thesis, analysis of the condition of the optical fibers in the Czech Republic is provided. Based on the results, the impact of the polarization mode dispersion on optical access networks was assessed. The next part of this thesis is focused on the active optical networks design, depending on the cost of implementation and operating costs. The main limiting parameters of the current passive optical networks are bandwidth and insertion loss of the optical distribution network. To increase the bandwidth a system based on optical time-division multiplexing with a bandwidth of 1.28 Tbit/s has been designed and created. By using polarization division multiplexing technique the system is also more tolerant to dispersions. In the last part of this thesis, a remote amplification system was verified by measurement and simulation. Based on the obtained results, a NG-PON2 network with a functional remote amplification system with a gain of more than 10 dB has been designed in the OptiSystem software.
|
|
|
DWDM in access networks
Šifta, Radim ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
The aim of this master´s thesis is an explanation of the problem of optical access networks with wavelength division multiplex, main purpose is to demonstrate the difference between simulation and real measurement. The thesis is divided into several basic thematic areas. At the beginning of thesis is outlined the basic division of multiplexing system, there are discussed the basic solutions of wavelength multiplexes and their possible combinations. The next chapter deals with the active elements, which are an essential part of xWDM systems such as optical lasers, detectors and amplifiers. The following chapter is focused on the passive elements, especially on the passive filters, which form a key part of the wavelength multiplex. Methods of measurement C/DWDM networks are discussed in the next part of thesis. The next chapter describes the topology used by active and passive optical networks. Penultimate part of this thesis consists of designs simulated models PON and WDM-PON networks and comparing their transmission parameters. The final part presents the results of practical measurements of experimental optical access network with wavelength division multiplex, the results are simultaneously compared with results of simulations.
|
|
|
Optical amplifier in laboratory practice
Šustr, Pavel ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
The aim of this thesis is to introduce to reader the application and use of optical EDFA amplifiers in optical transmission and to show wiring and practical test, including measurements on amplifier. The aim of this thesis is to propose the use of optical amplifier in laboratory practice for subject Optical networks. The thesis briefly introduces the problems of data transmissions through optical fibers with a focus on the use of optical amplifiers. The basic characteristic of optical transmission paths and the reasons for the use of optical amplifiers are described here. One entire chapter is devoted to distinction of optical amplifiers. Amplifiers can be divided according to location in the transmission path to the booster, in-line and pre-amplifiers and according to the used of amplifying technology to optical amplifiers with subsidies, semiconductor optical amplifiers and Raman optical amplifiers. The factors affecting the efficiency of optical amplifiers, such as noise and the level of saturated power are mentioned here too. The different types of optical amplifiers from the two producers are also described. From these amplifiers was chosen EDFA CzechLight Amplifier from Optokon to be used for the laboratory exercise in the subject of Optical networks. The use of EDFA optical amplifiers in optical transmission lines is mentioned here too. These amplifiers can be used in telecommunications transmission systems and for data transmission over long distances. They will find use in WDM transmission systems and cable TV distribution through the optical fiber to the end users. Practical measurements were performed on optical amplifier CLA-PB01F. In the transmission route was located attenuator and the dependence of output power to input signal power was measured. The amplification course was linear in the range of input values provided by the manufacturer. Laboratory exercise for the subject of Optical networks is aimed at preacquaintance of students with problems EDFA optical amplifiers and practical measurements with the optical amplifier CLA-PB01F. Students acquire basic theoretical knowledge of the issue and verify the functionality of optical amplifiers on a specific exercise. This work is destined for all who wish to get basic knowledge of optical amplifiers, their characteristics and possibilities of their use in optical transmission lines.
|
|
| |
guest ::
