A method in a radio communications network, the network comprising a base station and at least one user equipment, UE, wherein the base station comprises an antenna array comprising a plurality of antenna elements, the method being implemented in the base station and comprising the steps of precoding (1101) a multi-dimensional channel state information reference signal, CSI-RS, with a precoding virtualization matrix such that each antenna element of the antenna array is associated with a non-zero weight in at least two precoders of the precoding virtualization matrix, transmitting (1102) the multi-dimensional channel state information reference signal to a UE, receiving (1103) an identifier from the UE, wherein the identifier identifies a selected precoder from a codebook using (1104) the selected precoder to identify a desired precoder and transmitting (1105) a data signal to the UE using the desired precoder.