With the advancement in communication technology, maximum available bandwidth is utilized in wireless communication using antenna diversity. For this purpose multicarrier system like multicarrier code division multiple accesses (MC-CDMA) is used. In this paper, MC-CDMA system is implemented using Alamouti’s space time block codes. STBC) employee’sa special relationship between the receiver weights. It is proposed that non-conventional algorithms (NCA) like particle swarm optimization (PSO) are better than the conventional algorithms like least mean square (LMS) in order to attain the optimal value of receiver weights. The nonconventional algorithms are better than conventional algorithms to reduce the system complexity, bit error rate and the convergence rate of the system. The proposed algorithm can achieve the optimal minimum value in less number of iteration or cycles. This property improve the efficiency of the system. This is verified by the simulations.