Performance of a full rate quasi-orthogonal extended MIMO MC-CDMA system with efficient channel estimator

Multi-carrier CDMA and multiple antennas are very promising candidates for simultaneous use in 4G systems, since they achieve robustness, high spectral efficiency, and high data rates in rich scattering environments. Especially, in this work an efficient extended multiple transmit antenna scheme with M_T=4 elements and full rate mode for a downlink scenario has been designed and detailed evaluated. Its efficiency is enhanced by the use of an iterative architecture as a counterbalance of the quasi-orthogonal nature of the transmit diversity scheme, offering overall a higher degree of diversity gain. The evaluation has been performed in the framework of a realistic MC-CDMA system transmitting in a space-frequency format. Furthermore, the incorporation of an efficient pilot based MMSE channel identification, tracking and compensation scheme contribute resolutely to an accurate system design and evaluation. The evaluation has been performed over various spatial channel models according to IEEE 802.16e case of 3GPP.25.996 definition incorporating all IF/RF stages.