Interference Cancellation Based DFT-Precoded CDMA for Hybrid OFCDMA Multiple Access

A novel hybrid OFDMA/CDMA multiple access system for uplink communications in evolving 4G wireless systems is developed. Specifically, a DFT-precoded CDMA technique is proposed for the CDMA part of the multiple access. We elaborate on different configurations of precoded CDMA operation, and develop advanced receiver techniques, using frequency-domain interference cancellation. Detailed simulation results showing the performance of this multiple access approach is presented. Finally, we describe how the proposed approach has been incorporated in the currently developing Ultra Mobile Broadband (UMB) system, which is an evolution from the cdma2000 evolution standards family.