Semiunitary Precoding for Spatially Correlated MIMO Channels

— The focus of this paper is on spatial precoding in correlated multi-antenna channels where the number of datastreams is adapted independent of the number of transmit antennas. Towards the goal of a low-complexity implementation, a statistical semiunitary precoder is studied where the precoder matrix evolves fairly slowly with respect to the channel evolution. While prior work on statistical precoding has focussed on information-theoretic limits, most of these computations result in complicated functional dependencies of the mutual information with the channel statistics that do not explicitly reveal the impact of statistics on performance. In contrast, estimates that are directly in terms of the channel statistics are obtained here for the relative mutual information loss of a semiunitary precoder with respect to a perfect channel information benchmark. Based on these estimates, matching metrics are developed that capture the degree of matching of a channel to the precoder structur...

• Type: Journal
• Year: 2011
• Where: TIT
• Authors: Vasanthan Raghavan, Akbar M. Sayeed, Venugopal V. Veeravalli
• Keywords: Channel Statistics, Mutual Information, Semiunitary Precoder, TIT 2011