Patent ID: 8779978

Claim:
A method, in a transmitter, for selecting steering vectors for transmitting one or more streams between the transmitter and a receiver, wherein the transmitter has a plurality of transmit antennas, the receiver has a plurality of receive antennas, the number of receive antennas in the plurality of receive antennas is N R , and the number of streams in the one or more steams is N S , the method comprising: constructing a partial channel matrix corresponding to an estimate of a multiple input, multiple output (MIMO) channel between (i) the plurality of transmit antennas and (ii) a set of one or more of the receive antennas, wherein the number of receive antennas in the set of one or more of the receive antennas is M, and M is less than N R ; generating one or more independent vectors using the partial channel matrix, wherein the number of independent vectors in the one or more independent vectors is L, and L is a rank of the partial channel matrix; and when N S is greater than L, (i) selecting the one or more independent vectors as one or more first steering vectors to steer a first set of one or more streams in the one or more streams, wherein the number of streams in the first set of one or more streams is L, (ii) selecting one or more orthogonal vectors in a null space of the one or more independent vectors as one or more second steering vectors to steer a second set of one or more streams in the one or more streams, wherein the second set of one or more streams are not in the first set of one or more streams, (iii) utilizing the one or more first steering vectors for transmitting the first set of one or more streams, and (iv) utilizing the one or more second steering vectors for transmitting the second set of one or more streams.