Patent ID: 8009097

Claim:
A method in a transmitter for selecting steering vectors for simultaneously transmitting a plurality of streams (N S ) between the transmitter and a receiver, wherein the receiver has N R receive antennas, wherein the transmitter knows respective channels associated with M receive antennas of the receiver, and wherein M is less than N R , the method comprising: constructing a partial channel matrix that describes a multiple input, multiple output (MIMO) channel between the transmitter and the M receive antennas; generating L independent vectors using the partial channel matrix, wherein L is a rank of the partial channel matrix; and selecting a respective steering vector for each of the plurality of streams to be transmitted to the receiver, including: if N S is less than or equal to L, selecting N S of the L independent vectors as the steering vectors; if N S is greater than L, (i) selecting the L independent vectors as steering vectors to steer L of the plurality of streams; and (ii) selecting N S −L orthogonal vectors in a null space of the L independent vectors.