Unified framework for linear MIMO transceivers with shaping constraints

This letter considers optimum linear transceivers for MIMO channels under a general framework based on Schur-concave and Schur-convex cost functions, subject to shaping constraints on the transmit covariance matrix. Such constraints may be useful, for example, to impose spectral masks in cable systems, to control the power transmitted along certain directions in wireless systems, or to limit the dynamic range of the power amplifiers at the different transmit dimensions.