Space-time coded wideband CDMA systems

In this paper, we consider utilizing the space-time codes in the wideband CDMA system. We assume that there are multiple resolvable paths in the frequency selective fading channel. Analytical results show that in addition to spatial diversity, another diversity gain called multipath diversity is achievable. Performance criterion for full space multipath diversity gain is analyzed. We consider both the case that the receiver has the ideal channel state information and the case that there are errors in the channel state information available to the receiver. A RAKE receiver is used in the CDMA system to gain the multipath diversity. We derive the generalized RAKE receiver structure for the space-time block coding (STBC) coded wideband CDMA systems. The simulation results demonstrate the additional gain guaranteed by the multipath diversity.