Performance analysis of MIMO-IDMA system using spatial diversity in frequency-selective channel

In this letter, we investigate the bit-error rate (BER) performance of uncoded space-time transmit diversity (STTD) aided interleave division multiple access (IDMA) scheme for down-link (DL) communications. In this contribution, we consider the orthogonal structure based on Alamouti Space-Time code which offers full rate and full diversity. We realize such STTD using two transmit antennas and two receive antennas. At the mobile station, we exploit non-linear detection based on Maximum Likelihood detection algorithm to estimate the desired users´ signals. We evaluate the BER performance of STTD-IDMA system based on Rayleigh fading channels with multi-path scattering effects. We also compare the performance of our considered system with Vertical Bell laboratories Space-Time (VBLAST) architecture for the same IDMA system. Our simulation reveals that our considered STTD-IDMA system with ML detection algorithm provides better BER performance than VBLAST assisted IDMA system for DL communications.