Adaptive frequency-domain equalization for space-time block-coded DS-CDMA downlink

In this paper, we present low-complexity adaptive frequency-domain equalization (FDE) for space-time block coding (STBC) direct-sequence code-division multiple access (DS-CDMA) downlink system. The proposed scheme is powerful and computationally efficient, as the sophisticated matrix decompostion operations are not required in the processing, and some block recursive processing, such as block least mean square (BLMS) algorithm and modified block recursive least squares (BRLS) algorithm can be easily incorporated for equalizer adaption. Simulation results demonstrate the effectiveness of such adaptive FDE with regard to different Doppler shifts.