Discrete wavelets transform based space time block code multicarrier direct sequence CDMA

Abstract

Wireless digital communications is rapidly expanding resulting in a demand for systems that are reliable and have a high spectral efficiency. To fulfill these demands, the multicarrier modulation scheme, often called Multicarrier direct sequence code division multiplexing access (MC-DS-CDMA), has drawn a lot of attention. On the other hand space time block code-MC-DS-CDMA techniques have been considered to be a candidate to support multimedia services in mobile radio communications. In this work, a new structure for STBC-MC-DS-CDMA that based on discrete wavelet transform (DWT) is proposed. The proposed system has been examined with different channel models (AWGN, flat fading and selective fading) and proves that it has better BER performance than the conventional STBC-MC-DS-CDMA using FFT due to the low and high pass filters contained in the wavelet transform.