Performance analysis of a downlink MIMO MC-CDMA system with turbo coding and channel interleaving

In this paper, we present the multi-code Minimum Mean Square Error(MMSE) Ordered Successive Interference Canceller(OSIC) for downlink Multiple Input Multiple Output(MIMO) Multi-Carrier Code Division Multiple Access(MC-CDMA) systems and analyze its performance from the view point of Frame Error Rate(FER) and data throughput. It outperforms multi-user MMSE OSIC, since it can cancel other antenna interferences by using all known code information. We make performance comparisons between symbol interleaving before spreading and chip interleaving after spreading in the frequency domain for turbo encoded MIMO MC-CDMA systems. They demonstrate that chip interleaving method is superior to symbol interleaving method when the number of multipaths increases owing to randomization effect of burst errors, and is inferior to symbol interleaving method when the number of codes increases due to inter-code interference as SISO MC-CDMA systems [7]. Besides, we can derive spatial diversity as well as the frequency diversity from multiplexing turbo encoded data streams into transmitting antennas.