Date Added: Mar 2012
This paper presents an efficient method for calculating the Precoding Matrix Indicator (PMI) at the receiver. The PMI is required for MIMO precoding in the downlink of a 3GPP LTE system. The authors' method is based on maximizing the mutual information between the transmitted and received symbols with respect to the precoding matrix applied at the transmitter. The advantage of this method is that it is independent of the symbol alphabet (4/16/64 QAM) and code rate applied, which are signaled by the Channel Quality Indicator (CQI). This paper only focuses on the selection of the optimal PMI, such a procedure eventually allows to decouple both problems (CQI and PMI calculation), thereby reducing complexity.