Beamforming with partial channel knowledge

摘要

An apparatus for use in transmit beamforming to a beamformee having N_R receive antennas. The apparatus includes a controller configured to i) construct a partial channel matrix that describes a multiple input, multiple output (MIMO) channel between a beamformer and M receive antennas, wherein M is less than N_R, and ii) generate L independent vectors using the partial channel matrix, wherein L is a rank of the partial channel matrix. When a number N_S of one or more streams is greater than L, the controller is further configured to i) select the L independent vectors as steering vectors to steer L streams of the plurality of streams, and ii) select N_S−L orthogonal vectors in a null space of the L independent vectors as steering vectors to steer a remainder of the streams in the plurality of streams.