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Signal processing and receiving in UMTS system
Hron, Michal ; Hanus, Stanislav (referee) ; Kejík, Petr (advisor)
This semestral thesis be concerned with datailed analysis of receiving and processing signals in UMTS network system. Insistence of this work is setting to principals of RAKE receiver and processing signals in CDMA networks downlink channel. Through development system MATLAB simulates real function of RAKE receiver. This project is giving fundamental knowledges about receiving and processing of multipath signals to readers.
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Analysis of parameters and communication protocols on radio interface of UMTS networks
Plhák, Jan ; Skořepa, Michal (referee) ; Novotný, Vít (advisor)
These times the third generation cellular networks are getting in use increasingly and they dramatically exceed the parameters of second generation networks. Third generation networks are in contrast to older generations data-oriented, providing better maintenance in data and multimedia services. The most widespread third generation network is the UMTS, designed as succesor of GSM network. Master’s thesis is focused on parameters and communication protocols of radio interface of UMTS network. Parameters of radio interface affect the behaviour of mobile terminal through utilization of network services. This thesis describes individual protocols of radio interface and individual procedures, which the mobile terminal have to perform through its staying in the cell. Theoretical part of this thesis considers description of the UMTS network and individual procedures and parameters. Practical part is focused on measuring the radio interface and individual procedures in real UMTS networks. Some procedures are simulated in network simulation software. This thesis includes a lab task focused on this thema.
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Optimization of UMTS access network
Havlíček, Karel ; Kovář, Petr (referee) ; Novotný, Vít (advisor)
This master’s thesis deals with a UMTS radio access network optimization, containing radio interface analysis, services and procedures description, ways to correct parameters calculations and settings and other issues necessary for a correct access network operation. The goal is effective network operation, minimum costs and maximum performance and flexibility of the network. The optimization during system operation is important because of the system character. The UMTS system uses the WCDMA technology, where particular users share the same frequency band and they are distinguished from one another via code sequences. The capacity of such a system is then given by the interference level - each particular user increases the interference level by the value corresponding to his transmit power. The maximum cell capacity is determined by the maximum interference level at which users can still operate with required services, so it is related not only to the number of users, but also to their bit rate. The optimization allows effective usage of the system for different services with different requirements. The main optimization tool is the radio resource management, containing number of algorithms, such as admission control, which decides the acceptance or rejection of a new user demanding certain service, power control, which ensure that users transmit with a minimal power sufficient for required service, handover and cell selection algorithms etc. The major parameter used by these algorithms is a cell load factor, which is related to the interference level margin. There are several methods for the load factor estimation and some of them are described in this work. Some other optimization techniques are mentioned here, too. This work also contains a laboratory exercise proposal for radio resource management introduction using the OPNET Modeler network simulation tool.
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Current security trends in mobile networks
Jirkovská, Šárka ; Sobotka, Jiří (referee) ; Doležel, Radek (advisor)
This master's thesis deals with the issue of the security of GSM and UMTS mobile communication systems. In the thesis the principles of the authentication and encryption of both the mobile systems are described. Further, the constituent algorithms used for identity verification, key generation and encryption are mentioned. The commonly used algorithms are described along with their weaknesses. In the following part of this thesis, well-known attacks on GSM system are mentioned. In the part where UMTS system is dealt with one can find the algorithms used in this system to increase the security of transmitted data and authentication in comparison with GSM system. Therefore the whole process of authentication and encryption is described separately. In the last part the creation of programming models of authentication and encryption in GSM and encryption in UMTS is described. These models are created in the environment of Matlab version 2009b.
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QoS in UMTS
Kavan, Radovan ; Hanus, Stanislav (referee) ; Kejík, Petr (advisor)
This thesis treats of QoS (Quality of Service) in UMTS system. The term quality of service is frequently used, recently, however not only in computer networks, but also more and more in mobile networks also. Present system of 2nd generation (2G) GSM enables only limited exploitation of QoS function. System UMTS is a system of 3rd generation (3G) already and contains quality of service in greater measure which is ensured with number of algorithms and functions. Individual QoS functions enable effective utilization of radio interface, support maintenance of planned coverage and offer high spectral efficiency. Functions that cater to quality of service are called RRM functions (Radio Resource Management). There exist five basic functions in UMTS system that are Admission control (AC), Power control (PC), Load control (LC), Handover control (HC) and Packet scheduler (PS). These functions are responsible for control of network access, control of power, control of network load, control of handover and packet (bit rate) scheduling. Last three functions are usually collectively designated as Congestion control, control of network overload. UMTS layer model, differentiation of services, traffic classes and 3GPP concept are also discussed. In thesis the attention is piad to Admission control algorithm – control of network access – in the uplink direction and to different ways of load (in the cell) modeling. Individual approaches are simulated in MATLAB. A possibility of using algorithm in the real system is discussed in conclusion.
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Evaluation of influence of UMTS radio access network parameters on network performance using Opnet Modeler simulation environment
Konečný, Zbyněk ; Škorpil, Vladislav (referee) ; Novotný, Vít (advisor)
This bachelor thesis deals with testing the effect of various parameters and their subsequent influence on the operation of the entire UMTS access network. Each simulation will be implemented in Opnet Modeler, which is used for network testing based on packet switching. The aim of this work is the most effective operation of UMTS networks. Since the UMTS network uses a shared radio environment for all users close to one transmitter, the total capacity of one cell is dependent on the size of interference produced by mobile terminals in the cell. Increasing the capacity of cells can be done by properly elected handover. The first part of this work will therefore concern different types of handovers and their impact on the network operation. Nowadays communication through mobile packet networks is becoming more and more important and that is why the second part of this work will focus on the simulation of traffic UMTS networks. It will be simulated by the behavior of individual applications without the use of QoS. Then the application will be assigned to different quality classes and the quality of service will be compared with simulations without using QoS. The conclusion of this work will contain laboratory work, which should partly make the students familiar with the data traffic in the UMTS network through a simulation program – Opnet Modeler.
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Quality of Service Assurance in UMTS Network
Nesveda, Marek ; Novotný, Vít (referee) ; Hošek, Jiří (advisor)
The bachelor´s thesis deals with the assurance of the quality of service (QoS) in UMTS (Universal Mobile Telecommunications System) networks. It consists of theoretic and practical parts. The first, theoretic part first describes the quality of service assurance in general and then focuses on the area of the assurance of the quality of service (QoS) in UMTS network environment specifically. It describes the QoS concept in UMTS, typical UMTS network architecture, its components as well as various QoS classes defined in UMTS. It explains parameters that define the quality of service in UMTS network, and describes call set-up for the purposes of transmission between end users. The second, practical part of the bachelor´s thesis describes how to configure a complex UMTS network simulation model in OPNET Modeler, ver..14.5. It gives a detailed description of how to configure each network component and how to set its parameters, in two different scenarios: first including and then excluding QoS. In conclusion, the thesis summarises the results of the simulation in both scenarios, gives their explanations and compares them graphically.
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UMTS network simulation in Opnet Modeler environment and real network operation
Kuchár, Peter ; Molnár, Karol (referee) ; Novotný, Vít (advisor)
This bachelor thesis is devoted to mobile networks and specially to UMTS. First part contains theoretical information about mobile networks, history and present of mobile communication. It continues with comparasion between Node-B specification in the Opnet Modeler 14.5 and real node by 3GPP international community. Second part describes works on simulation and results of measured parameters. Simulation is focused on sensitive services like a VoIP or video. In simulation voice service is used VoIP and few data services running in background. Measurement in real network was executed in several networks which belong to different providers and supports different techniques. In real networks IxChariot was used. IxChariot is the industry’s leading test tool to predict device and system performance under realistic load conditions. Real network results and results from Opnet Modeler 14.5 simulation are practically equal. Aplication of Hamachi in real network did not have influence on the results measured.
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Optimization of Access to CDMA Networks
Kejík, Petr ; Masopust, Jiří (referee) ; Wieser, Vladimír (referee) ; Hanus, Stanislav (advisor)
The aim of this dissertation thesis is an optimization of access to CDMA networks. To be more specific, this thesis deals with an optimization of admission control in UMTS network. The first part of the thesis deals with the present progress of the particular topic. Thereinafter there is an analysis of admission control in UMTS system. An own UMTS simulation program was created in MATLAB. This program enables implementation and simulation of the selected admission control algorithms. The thesis is focused on load factor based, fuzzy logic based and genetic algorithms. The created UMTS simulator was used for the mutual comparison of all algorithms. The aims of this thesis are the suitable UMTS model design, evaluation and possible optimization of selected algorithms.
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