Channel conscious multi-user MIMO scheme together with a closed single-user MIMO

A method comprising: in an uplink transmission, receiving rank-1 channel quality indicator values ​​from one or more Teinehmerstation (s), wherein the channel quality indicator values ​​at least partly based on the channel information; in an uplink transmission, receiving two or more vectors of the one or more subscriber station (s); Determining which of the one or more subscriber station (s) having a best rank-1 channel quality indicator value; Determining a beamforming matrix based at least in part to the two or more vectors which have been received by the subscriber station having the best rank-1 channel quality indicator value; and in a downlink broadcast transmission using the beamforming matrix, which corresponds to the subscriber station having the best rank-1 channel quality indicator to the one or more subscriber station (s); and in an uplink transmission, receiving Rank-2 channel quality indicator values ​​from the one or more Teinehmerstation (s); if the rank-1 channel quality indicator value is greater than the rank-2 channel quality indicator values ​​from the individual subscriber stations or larger than the rank-2 channel quality indicator values ​​from a plurality of subscriber stations, then: Selecting a single-user multi-input (multiple-input), multiple output (multiple-output) -Rang-1 mode for data transmission; and ...