Space time spreading in forward links of the multicarrier DS CDMA system

In this paper, we consider space time spreading in the forward links of a MC-DS-CDMA system when random signature sequences are used. The performance of the system with different diversity order has also been analyzed. The numerical results show that considerable performance gain can be obtained by transmit diversity when the active user number is relatively small. As the number of the users increases, the diversity gain will decrease. It also suggests that it require multiuser interference cancellation when the active user number is relatively large