Aljerjawi, Mohamed (2006) Space-time spreading and transmit diversity for DS-CDMA systems over fading channels. Masters thesis, Concordia University.
|PDF - Accepted Version|
The application of space-time coding in wireless communication systems has shown to improve the quality of the received signal at the mobile user by placing the spatial diversity at the base station. In this thesis, we propose a simple space-time spreading scheme for code-division multiple-access (CDMA) systems over fast-fading channels. The proposed transmit diversity scheme is based on two transmit and M receive antennas and is suitable for Rayleigh fast-fading channels. In this we employ orthogonal spreading codes to exploit the time diversity introduced by the channel, and hence a two-fold of the diversity order obtained using existing spacetime spreading schemes is achieved. Nevertheless, for slowly-fading channels, we show that the proposed coding scheme reduces to existing schemes introduced in the literature with no performance degradation. Then, we examine the effect of using nonorthogonal spreading codes on the receiver performance. Our results show that using a simple adaptive decoder, based on the minimum mean-squared error (MMSE) criterion, the diversity order is still maintained and only a small loss in the signal-to noise ratio (SNR) is incurred relative to the ideal case with orthogonal codes.
|Divisions:||Concordia University > Faculty of Engineering and Computer Science > Electrical and Computer Engineering|
|Item Type:||Thesis (Masters)|
|Pagination:||xiv, 108 leaves : ill. ; 29 cm.|
|Degree Name:||M.A. Sc.|
|Program:||Electrical and Computer Engineering|
|Thesis Supervisor(s):||Hamouda, Walaa|
|Deposited By:||Concordia University Libraries|
|Deposited On:||18 Aug 2011 14:40|
|Last Modified:||18 Aug 2011 14:40|
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