Orthogonality-inherent space-time spreading and its performance analysis for MIMO-CDMA systems

An orthogonality-inherent space-time spreading for multiple input multiple output - code division multiple access (MIMO-CDMA) is proposed in this paper. It exploits a square space-time coding to provide full transmission rate and full diversity order for any transmit antennas using arbitrary real constellation. Due to the orthogonality inherent in spreading, the constructed system can be suitable used in flat-fading channels and with fewer restrictions on number of antennas. Numeric analysis shows the involved system can achieve a good performance under arbitrary code length.