Residue number system arithmetic inspired applications in cellular downlink OFDMA

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Show simple item record Zhu, Dalin 2009-11-04T14:19:53Z 2009-11-04T14:19:53Z 2009-11-04T14:19:53Z
dc.description.abstract In recent years, orthogonal frequency division multiplexing (OFDM) scheme has received significant research interest due to its capability of supporting high data rates in hostile environments. As compared to conventional single-carrier modulation schemes, OFDM benefits from low complexity equalization filters and high spectral efficiency. A multiple access implementation of OFDM, i.e., orthogonal frequency division multiple access (OFDMA) has been considered as the multiple access (MA) scheme in 3GPP LTE, or LTE advanced downlink. In cellular OFDMA, frequency hopping (FH) is widely used to exploit frequency diversity gain and improve system throughput; and pilot patterns that have low-cross correlation are employed to improve the quality of channel estimation. However, there are numerous unsolved problems that need to be addressed in frequency hopped and pilot assisted OFDMA systems. Surveying the prior works in the literature, we find that limited research efforts have focused on coping with the inherent disadvantages regarding OFDM in cellular OFDMA systems. In this thesis, we employ the so-called residue number system (RNS) arithmetic concentrating on (a) FH pattern design for minimizing/averaging intra/inter-cell interference, (b) pilot pattern design for improving the quality of channel estimation, and (c) pilot pattern design for facilitating time-frequency synchronization and device identification in multi-cell OFDMA. Regarding (a), RNS-based FH patterns not only preserve orthogonality within the same cell, but also have the minimum number of symbol collisions among adjacent cells. Additionally, the RNS-based method exhibits consistent system performance and more frequency diversity gains as compared to previous efforts. With respect to (b), RNS-based pilot pattern design generates more unique pilot patterns than conventional methods. This results in low probability of pilot-to-pilot collisions, which in turn, significantly improves the quality of channel estimation from the system level perspective. For (c), as a special case of linear congruence sequences, RNS-based pilot patterns have good auto-correlation properties, which are extremely helpful in time-frequency synchronization and device identification. en_US
dc.language.iso en_US en_US
dc.publisher Kansas State University en
dc.subject residue number system arithmetic en_US
dc.subject cellular downlink OFDMA en_US
dc.subject frequency hopping pattern en_US
dc.subject hopping pilot pattern en_US
dc.title Residue number system arithmetic inspired applications in cellular downlink OFDMA en_US
dc.type Thesis en_US Master of Science en_US
dc.description.level Masters en_US
dc.description.department Department of Electrical and Computer Engineering en_US
dc.description.advisor Balasubramaniam Natarajan en_US
dc.subject.umi Engineering, Electronics and Electrical (0544) en_US 2009 en_US December en_US

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