Low-Complexity Structured Precoding for Spatially Correlated MIMO Channels

The focus of this paper is on spatial precoding in correlated multi-antenna channels, where the number of independent data-streams is adapted to trade-off the data-rate with the transmitter complexity. Towards the goal of a low-complexity implementation, a structured precoder is proposed, where the precoder matrix evolves fairly slowly at a rate comparable with the statistical evolution of the channel. Here, the eigenvectors of the precoder matrix correspond to the dominant eigenvectors of the transmit covariance matrix, whereas the power allocation across the modes is fixed, known at both the ends, and is of low-complexity. A particular case of the proposed scheme (semiunitary precoding), where the spatial modes are excited with equal power, is shown to be near-optimal in matched channels. A matched channel is one where the dominant eigenvalues of the transmit covariance matrix are well-conditioned and their number equals the number of independent data-streams, and the receive covari...

• Type: Journal
• Year: 2008
• Where: CORR
• Authors: Vasanthan Raghavan, Akbar M. Sayeed, Venugopal V. Veeravalli
• Keywords: CORR 2008, Education, Independent Data-streams, Precoder Matrix, Transmit Covariance Matrix