An interference-free MIMO-CDMA system spread with orthogonal complementary code for multipath fading scenarios

To overcome the problem that the performance of traditional MIMO-CDMA system would degrade badly in frequency-selective fading channel conditions, a novel interference-free MIMO-CDMA system spread with Orthogonal Complementary(OC) code is proposed in the paper. The system utilizes a novel transmitter structure, which combines OC code spreading and spatial delay multiplexing technique. Therefore, only simple correlation operation is needed at the receiver to effectively resist interferences caused by multipath propagation effect, and maximum-ratio-combination (MRC) can be employed to further resist channel fading. The proposed system provides higer BER performance and lower hardware complexity, compared with traditional MIMO-CDMA system employing singler code spreading and VBLAST scheme. Mathematical expressions and theoretical analysis of the system are presented. Simulation results validate the perfect anti-interference properties of the proposed -system.