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Communication devices over GSM/GPRS
Prečan, David ; Růčka, Lukáš (referee) ; Herman, Ivo (advisor)
This master thesis deals with a data remote transmission by means of SMS and GPRS technology. The overview of current solutions is presented and then a remote temperature measurement and a data transmission employing a communication module GSM/GPRS TM1 through GSM network using GPRS technology is described. As a response to an impulse, the communication module sends SMS. The technical solution is described in details including HW and SW design of the data transfer and processing equipment using a ATmega 162 microprocessor. This equipment communicates with a server (PC), which displays the measured temperature. A prototype which was used for a validation of the design is also described.
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UMTS radio access network optimization in Opnet Modeler environment
Toman, Petr ; Herman, Ivo (referee) ; Novotný, Vít (advisor)
The differences between networks of mobile operators can be in their achitecture or the optimization of each network. The architecture is standardized which means there will only be differences in the willingness of mobile operators to invest in newer network elements. Network optimization is more important. The way of optimization isn't strictly given and depends on how the operator deals with it. The most important attribute in optimization is balance. The operators try to achieve balance among three important parameters. Those are capacity, coverage and maintaining QoS. Optimization depends on RRM algorithms. The algorithms include various functions such as admission control, congestion control, handover control, power control, etc. These elements don’t only affect the optimization but also affect each other, because they cooperate with each other. For example, an incorrect admission control of the network leads either to frequent network congestion because of a large number of participants in the network (participants are dissatisfied with the services offered by the operator) or to low utilization of the network because of too few participants in the network (the operator is dissatisfied because he is losing the possible earnings). Neither of these posibilities is good for the mobile operator, therefore it is important that the admission control is well balanced.
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The V-mux test system
Morávek, Patrik ; Herman, Ivo (referee) ; Novotný, Vít (advisor)
An optical network technology is the network technology that meets given requirements for a fast and reliable long-distance information transmission. Optical fibres can offer undoubted features where other communication technologies are near their limits or stand in front of insurmountable problems. The intensive research of last years is focused on optical transmission features utilization in the optimal way. Especially an optical signal processing in active network devices without a need for electrical conversation is a topic of high interest. V-Mux is an optical network device that accomplishes above mentioned requirements for modern optical network devices. It is a device that multiplexes and drops an optical signal in its native light form into or from optical fibre. Basic micro electro-mechanical components, which the V-Mux is built from, are high end precise devices. The whole complex V-Mux has to meet strict rules and specifications as the components itself. That is why a control system has to be included in the production process to keep quality and right functionality. This diploma thesis is focused on a development of the testing system that will help in the automated control procedure in the V-Mux production. A brief introduction to optical network technologies and a description of the GPIB bus form a first part of the thesis. The next part focuses on the V-Mux itself and the proposal of the test station with its component description. The last part deals with a developing of the software for the V-Mux testboard and a user application that will be used for the test system initialization.
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Converter USB/RS 485
Henzl, Václav ; Hanák, Pavel (referee) ; Herman, Ivo (advisor)
This thesis is describing problematic of realisation of converter from USB type media into the universal RS-485 bus which is mainly used for the industrial applications (author is using frequently as a device in order to enable communication between server and RFID devices). This thesis contains theoretical information, realisation of the device itself and assesment of reached targets.
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Communication systems based on IP telephony
Zimek, Josef ; Kapoun, Vladimír (referee) ; Herman, Ivo (advisor)
My master’s thesis is focused on designing and creating communication network, which provides communication between two independent networks through encrypted tunnel. My solution is based on routers formed by older personal computers with FreeBSD like a operating system. Between routers is created static encrypted tunnel by using IPSec protocol. Voice services provides packet oriented exchange Asterisk with support of signaling protocol SIP. This solution can be used eg. for connecting remote branch to headquarters of company and then can branch utilize shrared resources. To headquarters can connect also remote workers from their home. In this case are used SSL certificates to authentication of user. This scenario is very required today.
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Communication system for the blind - the fixed part
Botko, Ondřej ; Koton, Jaroslav (referee) ; Herman, Ivo (advisor)
The thesis deals with problems of navigation blind in buildings, where is not possibility navigation by GPS (Global Positioning System). This thesis contain resolution through the use of communication units, placed in floor of buildings. This comunication units, equipped with receiver and transmitter, can give direction for blind by send own identification to transceiver in speciál stick (the thesis does not contain solving of the stick), which can information blind of position. Two comunication unit solution are available, that differs by using component part. The main difference is in use control unit of circuit. First circuit use as control unit ATAR862-3 (microprocessor and transmitter in one case) and the second one use microprocessor ATmega 8L. Both component made by Atmel corporation. Circuit with ATmega 8L is more exacting on curent consumption, but solving this problem is available and communication unit has low pretensions and long life. The part of thesis is program, which solving communication protocol for no-problem communication between unit in floor and special stick.
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Communication system for the blind - the mobile part
Dadák, Jiří ; Rampl, Ivan (referee) ; Herman, Ivo (advisor)
Orientation in big administration buildings can be very difficult for visually impaired people. Although most of the buildings are equipped with elevators, the buttons of which are designated with Braille characters and acoustic signals, it might be very difficult for the visually impaired to actually find the particular office. Even if there were descriptions in Braille at each office door, it would prove very complicating for the visually impaired individual to localize the descriptions in the first place, especially in case of a large number of offices in the building. That may also concern other important places, such as toilets, inside a building. In this thesis, I am going to present a design proposal of a communication system which uses transceivers placed at significant points in a building and receivers placed at the end of the white cane for orientation inside a building.
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Analysis of UMTS signalling
Trojáček, Jaroslav ; Herman, Ivo (referee) ; Havelka, Dušan (advisor)
Master thesis is focused on signalling analysis of third-generation mobile network UMTS. In first part of master thesis is described a question of standard IMT-2000, introduces the principles of the WCDMA air interface, gives a wide overview of the UMTS system architecture and signal processing. In second part of master thesis is described a question of signalling analysis, including general protocol model for UTRAN terrestrial interfaces. This chapter is focused on elementary procedures, Radio Resource Management procedure examples, Mobility Management procedure examples and Call Control procedure examples in the first place. Last chapter of master thesis is focused on radio network planning of UMTS with practical location of basic station Node-B.
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Secure applications with microcontrollers
Sobotka, Jiří ; Herman, Ivo (referee) ; Balík, Miroslav (advisor)
This thesis deals with problematics of secure operations of microcontrollers. During long-term use, the microcontrollers can be affected by error or malfunction. The aim of this thesis is to describe the types of errors which can affect processors, cause of creation of these errors and possibilities of preventing malfunctions in microcontrollers. There is many problems connected with operation of microcontrollers, therefore there are many methods to prevent these problems. First part of this thesis deals with description of types of mistakes and with attempts of theirs modelling. Second part of this thesis narrate possibilities of preventing each type of mistake during designing the system or during operation of microcontroller and explaining methods of fault toleration by using redundant circuits in case of hardware fault and by modifying source code in case of software faults. In third part the hazard analytical methods are described. The recognition of events able to damage the system has high importance. The risk analysis takes place during developing and during operation of the system. Fourth part is trying to describe some of the processor testing techniques as main method of finding errors before operating use of microcontroller. Last part attempts to practical draft of testing algorithm for chosen microprocessor and application of one of analytical techniques.
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