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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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Architecture of channels in UMTS networks
Souček, David ; Vyoral, Josef (referee) ; Novotný, Vít (advisor)
Mobile networks and their services are one of the most importantly developing domains of telecommunication these days. The mobility of subscribers and services is the funda-mental need for dynamic development of not only the economics, but also of other fields of human performance. The charge for the mobility and integration of various kinds of services in mobile networks is an extensively complicated architecture and a protocol equipment. The important aspect of mobile networks is the efektivity of utilization of radio sources, which are scarce and form so called narrow neck of the communication chain between the mobile terminal and the network terminal. That is the reason why the perfection of mobile technologies is closely related to the improvement of efficiency of the usage of radio sources, which is reflexed in the UMTS network by an extensively complicated layer architecture of communication channels, that is formed by three layers as distinct from the GSM/GPRS network, where the architecture of channels was in two layers.
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