Abstract:
Space-time spreading has been employed to exploit the spatial diversity in multiple-input multiple-output (MIMO) code-division multiple-access (DS-CDMA) systems. In the presence of multiuser interference, resulting from the cross -correlation between users' code sequences, the full system diversity cannot be achieved when using the conventional matched receiver. The performance of space–time transmit diversity is examined in a multiuser direct-sequence code-division multiple access (DS-CDMA) system over Rayleigh and Rician fading channels. The underlying space–time system employs N = 2 transmit antennas and L receive antennas at the user side and base-station. Signal to Noise ratio is calculated at the output of the space-time combiner and the performance of the system is analyzed when using the linear decorrelator detector to combat the effect of multiuser interference.
Keywords: Direct-sequence code-division multiple access, maximal-ratio combining, multiuser detection, transmit diversity.