Performance enhancement of a wavelet based multicarrier DS-CDMA system through multistage interference cancellation

Abstract

This paper proposes a multistage interference cancellation scheme for a multicarrier direct sequence code division multiple access (MC-DS/CDMA) system using wavelet packet transform (WPT) as the basis function. The timing errors in the proposed system are reduced using a novel oversampling method with multiple WPTs. The proposed method improves the immunity to multipath interference (MPI) and intercarrier interference (ICI). To reduce the effect of multiuser interference, the system uses a coherent multistage interference cancellation scheme. Since the spreading in each subcarrier is independent, interference cancellation can be done in parallel for different subcarriers. Extensive computer simulations for different channel conditions have been performed to assess the suitability of the proposed system for high-rate wireless data transmission.