1. A multi-stream transmission method for transmitting N data streams allocated to K different users, the method being implemented by a transmitter for a multi-user MIMO system having N T transmit antennas and ∑ k = 1 K ⁢ N R k receive antennas associated with K receivers respectively associated with the K users, the method comprising: performing by the transmitter a succession of first and second different iterative algorithms for calculating K precoding matrices of a linear precoder and K decoding matrices of a receiver, the receiver being of a normalized matched filter type with a Frobenius norm for the first iterative algorithm, and the second iterative algorithm being initialized by a value output by the first iterative algorithm; and before each calculation of the precoding matrices, calculating by the transmitter weights for weighting all of the data streams, wherein K, N T , N, and N R k are integer numbers with N>K.