Wavelet packet waveforms for multicarrier CDMA communications

Abstract

Wavelet packets have been found a promising candidate for user signature waveforms in code division multiple access communication systems due to their good orthogonality property. In this paper we investigate the use of wavelet packets in multicarrier CDMA. In conventional multicarrier CDMA systems, the multi channel signals are modulated on sub carriers of sinusoid waveforms, using FFT to achieve fast computation. To combat multipath channel effect, a guard interval is inserted between consecutive data symbols. On the other hand, wavelet packet waveforms have the property of localization in both time and frequency domains. This property enables the time domain diversity of the multi carrier signal so that the need for guard intervals is eliminated by time domain diversity combining. Simulations are shown to compare the performance of the wavelet packet receiver design with the DFT based multi carrier CDMA system.