Performance Analysis of Adaptive Polarized MIMO Pre-RAKE Combined Transmit Diversity System in FDD

In this paper, an advanced closed loop PolarizedMultiple-InputMultiple-Output Pre-RAKE Combined Transmit Diversity “Pol MIMO Pre-RAKE CTD” system is proposed for the downlink. The proposed system is designed and analyzed in frequency division duplex mode. The numerical results demonstrate that it can achieve a significant performance gain, especially for dense urban and suburban environments. This is in addition to simplifying the receiver structure of the mobile terminal as well as reducing its power consumption and the spatial dimension of theMIMO system. For the same spatial dimension, the proposed system will be comparedwith the adaptive polarizedMIMOPre-RAKE system, employing selection transmit diversity technique. Both systems will be investigated for various transmit diversity degrees in the Node B and under different numbers of users. Also, the performance will be studied using both random and orthogonal spreading codes between users. The effect of the cross-polarization discrimination on the Bit Error Rate performance will be discussed. Moreover, a performance comparison will be presented in case of using both nonoverlapped and orthogonal carriers between the Pre-RAKEs. Finally, the proposed system will be examined under different numbers of channel paths and Pre-RAKE fingers.