Interference Cancellation Based DFT-Precoded CDMA for Hybrid OFCDMA Multiple Access
01 January 2007
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 elaborated for the CDMA part of the multiple access. Different configurations of precoded CDMA operation are proposed, and advanced receiver techniques, using frequency-domain interference cancellation, are analyzed. Detailed simulation results showing the performance of this multiple access approach is presented. System capacity calculations to quantify the improvements due to the above approach are provided. 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.