Abstract: The invention relates to a method 20 in a base station 2 for determining a transmission rank. The base station 2 controls two or more transmit antenna ports 3a, 3b for supporting a multi-antenna transmission mode and for transmission of data on a channel for communication with a user equipment 4. The method 20 comprises receiving 21 a rank indicator from a user equipment 4, the rank indicator indicating the number of spatial multiplexing layers recommended by the user equipment 4, and determining 22 the transmission rank based on a channel imbalance factor CIF, wherein the channel imbalance factor CIF quantifies a difference in receive power of the two or more transmit antenna ports 3a, 3b. The invention also relates to a base station, methods in user equipment, user equipment, computer programs, and computer program products.