Tap and transmit antenna correlation based precoding for MIMO-OFDM systems

Spatial Multiplexing (SM) is an effective means for enhancing the transmission data rate in Multiple-Input Multiple-Output (MIMO) systems, particularly when used in combination with precoding. Precoding based on the knowledge of the slow-varying statistics of the channel exploits this information at the transmitter to combat the effect of fading in SM systems. Moreover, this technique requires little feedback overhead and can therefore be used in fast fading environments. In this paper, we consider a MIMO-Orthogonal Frequency Division Multiplexing (OFDM) system. We exploit the knowledge of the tap correlation and the transmit antenna correlation present in the frequency-selective channel to propose a low-complexity precoding scheme that minimizes the sum of the symbol Mean Square Errors (MSEs) over all subcarriers. Simulations show that exploiting the knowledge of both the tap and the spatial correlation improves the performance of the MIMO-OFDM system.