Title :
Space time spreading with modified Walsh-Hadamard sequences
Author :
Vial, P. ; Wysocki, B.J. ; Raad, I. ; Wysocki, T.
Author_Institution :
Wollongong Univ., NSW, Australia
fDate :
30 Aug.-2 Sept. 2004
Abstract :
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 used. It is shown using simulation that significant improvement of the order of 0.5-2 dB is possible using these sequences instead of the standard Walsh code previously proposed.
Keywords :
Hadamard codes; adjacent channel interference; binary sequences; cellular radio; correlation theory; interference suppression; space-time codes; spread spectrum communication; transmitting antennas; MAI; adjacent interferer; cellular radio; cross-correlation performance; interference mitigation; modified Walsh-Hadamard codes; modified Walsh-Hadamard sequences; multiple access interference; mutual interference; performance; space time spreading; transmit antennas; Base stations; Binary phase shift keying; Degradation; Equations; Multiple access interference; Receiving antennas; Sociotechnical systems; Space stations; Telecommunication computing; Transmitting antennas;
Conference_Titel :
Spread Spectrum Techniques and Applications, 2004 IEEE Eighth International Symposium on
Print_ISBN :
0-7803-8408-3
DOI :
10.1109/ISSSTA.2004.1371840
