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Simulation of UMTS system
Predajňa, Martin ; Prokopec, Jan (referee) ; Kejík, Petr (advisor)
The bachelor’s thesis deals with modeling of UMTS system in downlink. It is focused on signal processing in physical layer and observes BER depending on parameters of model of real environment by setting different interruption. Basic architecture of UMTS system, channel coding and multiplexing of transport channels to physical channels is described in this thesis. Radio frame structure for downlink dedicated physical data channel is also described there. Using of pseudorandom sequences in CDMA systems and their properties are key parameters for observation of BER. Simulation uses single-user model in basic band, which enables to observe the influence of noise and narrowband jamming. These channel properties have impact on BER, which is used for evaluation of UMTS system. The orthogonality of sequences is influenced by multi access interference so detection of required signal (which uses correlation properties of spreading sequences) is limited.
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Compressing Pseudorandom sequences
Vald, Denis ; Holub, Štěpán (advisor) ; Růžička, Pavel (referee)
Generators of pseudorandom sequences are widely used objects, not in the least place because of their application in stream ciphers. One of the ways to improve resistance to different types of attack is to use compression on the generated sequence in order to remove redundant information, that might lead to an attack against the generator. In this work we try to explore from a wider perspective the theoretical foundations for compressing pseudorandom sequences created thus far. Using this general view we will examine some known attacks against the PRN generators and look for a way to resist such attacks.
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Compressing Pseudorandom sequences
Vald, Denis ; Holub, Štěpán (advisor) ; Růžička, Pavel (referee)
Generators of pseudorandom sequences are widely used objects, not in the least place because of their application in stream ciphers. One of the ways to improve resistance to different types of attack is to use compression on the generated sequence in order to remove redundant information, that might lead to an attack against the generator. In this work we try to explore from a wider perspective the theoretical foundations for compressing pseudorandom sequences created thus far. Using this general view we will examine some known attacks against the PRN generators and look for a way to resist such attacks.
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|
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Simulation of UMTS system
Predajňa, Martin ; Prokopec, Jan (referee) ; Kejík, Petr (advisor)
The bachelor’s thesis deals with modeling of UMTS system in downlink. It is focused on signal processing in physical layer and observes BER depending on parameters of model of real environment by setting different interruption. Basic architecture of UMTS system, channel coding and multiplexing of transport channels to physical channels is described in this thesis. Radio frame structure for downlink dedicated physical data channel is also described there. Using of pseudorandom sequences in CDMA systems and their properties are key parameters for observation of BER. Simulation uses single-user model in basic band, which enables to observe the influence of noise and narrowband jamming. These channel properties have impact on BER, which is used for evaluation of UMTS system. The orthogonality of sequences is influenced by multi access interference so detection of required signal (which uses correlation properties of spreading sequences) is limited.
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