Performance of space-time block coded Mc-CDMA over Rayleigh channel

For future wideband wireless networks, space diversity schemes based on multiple antennas at the receiver and/or at the transmitter are quite attractive to combat fading and enhance the transmission performance. In this paper, MC-CDMA technique combined with Space-Time Block Code (STBC)is studied in the case of N-t transmit antennas. and N-r (equal to one or two) receive antennas to offer a diversity order of NtNr for a 2bps/Hz spectral efficiency. Four Single-user Detection techniques are discussed and compared in the synchronous case of the downlink over frequency selective Rayleigh channel. Among all these techniques, simulations results show that the Minimum Mean Square Error(MMSE) provides the best performance. Moreover, it is demonstrated that multi-user MC-CDMA systems performances are improved due to the transmit diversity exploited by STBC and the receive diversity exploitted by multiple receive antennas.