Date Added: Jan 2010
For wideband applications, Code Division Multiple Access (CDMA) based systems deployed on multi-carriers could provide effective multiple access capabilities. First was the Multi-Carrier Direct-Sequence CDMA (MC-DS-CDMA) system where multicarrier modulation was used with time spreading. The other was the multicarrier CDMA where multicarrier modulation and frequency domain spreading were used. Even though MC-CDMA provides frequency diversity, it is vulnerable to Multiple Access Interference (MAI) in frequency selective subcarriers. In order to realize the benefits from both systems, a multicarrier CDMA system was proposed where both frequency and time spreading codes were used according to the channel conditions.