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Full-Text Articles in Physical Sciences and Mathematics
Space Time Spreading With Modified Walsh-Hadamard Sequences, Peter James Vial, Beata J. Wysocki, I. Raad, Tadeusz A. Wysocki
Space Time Spreading With Modified Walsh-Hadamard Sequences, Peter James Vial, Beata J. Wysocki, I. Raad, Tadeusz A. Wysocki
Faculty of Informatics - Papers (Archive)
Previous work has shown that the performance of a space time spreading (STS) system using Walsh codes with two transmit antennas at the base station (BS) is degraded in the presence of mutual interference from adjacent sectors in the same cell. We use modified Walsh-Hadamard sequences exhibiting improved cross-correlation performance, which potentially mitigates the effects of MAI (multiple access interference). The presented study also looks at variation of sets of different modified Walsh-Hadamard codes being used by the adjacent interferer, with a hundred randomly selected pairings being chosen, as well as the case where one set of alternate codes is …
Complex Orthogonal Sequences From Amicable Hadamard Matrices, Le Chung Tran, Jennifer Seberry, Beata J. Wysocki, Tadeusz A. Wysocki, Tianbing Xia, Y. Zhao
Complex Orthogonal Sequences From Amicable Hadamard Matrices, Le Chung Tran, Jennifer Seberry, Beata J. Wysocki, Tadeusz A. Wysocki, Tianbing Xia, Y. Zhao
Faculty of Informatics - Papers (Archive)
The paper deals with the novel technique of designing complex spreading sequences with only four phases (0.257/spl pi/, 0.75/spl pi/, 1.25/spl pi/, 1.75/spl pi/). The interesting feature of those new sequences is the fact that not only the complex sequences are orthogonal but the real parts and imaginary parts are independently orthogonal. This can be utilized for spreading of complex constellation signals where the independent spreading using bipolar sequences (real part for in-phase component and imaginary part for quadrature component) can be applied. The paper introduces the theoretical background, and some example constructions of the amicable Hadamard matrices and the …