Patent ID: 7706469

Claim:
A method of transmitting a transmit vector comprising symbols to be delivered within a resource unit from a transmitting station with one or more transmit antennas to one or more receiving stations with one or more receive antennas, the method comprising: obtaining information on states of channels between the one or more transmit antennas and the one or more receive antennas; computing, on the basis of the states of the channels between the one or more transmit antennas and the one or more receive antennas, a covariance matrix R nn , a combined channel matrix H, and a block-diagonal linear operator V of decoding matrices of the one or more receiving stations; precoding the transmit vector with a precoding matrix P fulfilling the equations ( H H V H VH+λI ) P=H H V H (1a) V i ( H i PP H H i H +R nn,i )= P i H H i H , i=1 . . . K (1b) trace( P H P )= P tr (1c) where superscript H stands for conjugate transpose, λ denotes lagrangian multiplier, R nn,i noise covariance matrix for the i:th user and P tr is a power constraint; performing filtering in the one or more receiving stations using a receiver filter corresponding to the block-diagonal linear operator V.