Orthogonalized Spatial Multiplexing for Rank-3 Transmission in Closed-Loop MIMO Systems

Abstract

Orthogonalized Spatial Multiplexing (OSM) scheme for Multiple-Input Multiple-Output (MIMO) channels has been originally developed for transmitting two data streams, which allows simple maximum ikelihood decoding at the receiver with small feedback information. In this paper, by extending the existing OSM scheme, we propose a new Spatial Multiplexing (SM) system which supports a larger number of data streams. To this end, we adopt three successive rotation precoding with four phase angles, so that we can decompose the MIMO channel into two identical subchannels. Moreover, it is shown that we can further improve the performance by applying multidimensional constellation rotation. Through the numerical results, we show that the proposed scheme outperforms the Singular Value Decomposition (SVD) based scheme while the computational complexity and the feedback overhead are reduced.