Space-Time Coding and Spatial Multiplexing in MIMO Multicarrier CDMA

This paper proposes a new downlink MIMO multicarrier CDMA system that combines spatial multiplexing and space-time coding in order to simultaneously exploit higher spectral efficiencies and diversity gains. The system design of three other more conventional MIMO MC-CDMA receivers, based on minimum mean square error (MMSE) and multiuser detection (MUD) is also presented. All the structures are compared in terms of complexity and BER performance over frequency selective multipath Rayleigh fading channels considering both perfect and imperfect channel knowledge at the receiver. It is shown that the proposed multistage serial interference cancellation (MSIC) method significantly outperforms the other structures and is very robust to channel estimation error, while being at a relatively low complexity level.