Precoding with Known Transmitter Coupling and Spatial Covariance Matrices

Proposed in this paper is a closed-form precoding scheme, with known transmitter coupling and spatial covariance matrices. It ensures that, for multiple-input multiple-output (MIMO) systems with fixed-aperture transmit antenna arrays, system capacity increases with the number of element antennas when coupling and spatial covariance matrices are known at the transmitter and the radiated power constrained is implemented. Proportional power allocation is employed in this precoding scheme. It is shown that the performance of proportional power allocation approaches that of water filling, the optimal power allocation scheme, while in contrast to waterfilling, proportional power allocation is of much lower computational complexity.