A method is disclosed which is intended for use in multiple-input multiple-output wireless communication systems which have a plurality of adjacent cells (cell A, cell B, cell C, cell D), each containing one or more base stations which co-operatively transmit signals to, and receive signals transmitted from, a user equipment (UE). The user equipment is operable to feed back to the relevant base station(s) CSI reports relating to channel(s) between the relevant base station(s) and the users, the base stations are operable to adapt signals for transmission to users, based on the fed back channel state information. The method involves the UE being configured to select at least one cell to be the subject of a CSI report, and to send the CSI report with an indication of the subject cell(s). Feedback overhead on the uplink is reduced when many cells co-operate in transmission to the user equipment.