Date Added: Mar 2010
Recently, a new Multi-Carrier CDMA (MC-CDMA) systems with Cyclic-Shift Orthogonal Keying (CSOK) has been proposed and shown to be more spectral and power efficient than conventional MC-CDMA systems. In this paper, a novel extension called the Multiplexed CSOK (MCSOK) MC-CDMA system is proposed to further increase the data rate while maintaining a low Peak-to-Average Power Ratio (PAPR). First, the data stream is divided into multiple parallel substreams that are mapped into QPSK-CSOK symbols in terms of cyclic shifted Chu sequences. Second, these sequences are repeated, modulated, summed, and placed on IFFT subcarriers, resulting in a constant-modulus multiplexed signal that preserves the desired orthogonality among substreams.