Abstract: The Multi-Carrier Code Division Multiple Access (MC-CDMA) is a strong candidate for the future wireless systems to provide high speed packet data and multimedia streaming services. The MCCDMA faces the problem from Multiple Access Interference (MAI) due to failure of orthogonality among the users under the frequency-selective fading channels and multipath effects. In this study, the MCCDMA system is developed by joining with Space-Time Block Coding (STBC) scheme and Multi Input Multi Output (MIMO) scheme for capacity enhancement. Along with STBC and MIMO schemes, Orthogonal Complete Complementary (OCC) spreading codes with suitable cross-correlation properties determine the interference-resist capability as well as spectral efficiency. Further, the mitigation of MAI in MCCDMA systems is approached in different way to minimize the error rates and to improve the spectral efficiency. The constellation movement scheme is proposed for Quadrature Amplitude Modulation (QAM) signal set where the constellation of one of the users is moved relative to the other by an angle chosen adaptively according to the channel conditions which causes MAI in order to satisfy minimum distance threshold at the detectors. The simulation result shows that the developed MCCDMA system achieves significant performance improvement in terms of Bit Error Rate (BER) and spectral efficiency compared to MCCDMA systems with Wash and Gold spreading codes. It also shows that the proposed constellation movement scheme combats MAI further and achieves a significant improvement in user capacity.