Many conventional communication systems apply beamforming coefficients to signals before transmission to help compensate for channel conditions. These beamforming coefficients may affect the power generated by the power amplifiers and may result in non-uniform power loading among the antennas and increased nonlinear distortion. Multicarrier communication systems, such as orthogonal frequency division multiplexed (OFDM) systems, are particularly sensitive to nonlinear distortion in their power amplifiers because they transmit multicarrier symbols on a plurality of closely-spaced orthogonal subcarriers. Thus there are general needs for multicarrier transmitters and methods for beamforming that may reduce non-uniform power loading among antennas.
USPTO Backgrounds
USPTO Backgrounds