A method for operating a user equipment (UE) comprises, in response to a condition being satisfied, selecting, from a full basis set, a basis subset comprising Ml bases for each layer l of a plurality of v layers; in response to the condition not being satisfied, selecting, from the full basis set, an intermediate basis set comprising N′ bases that are common among the plurality of v layers, and selecting, from the selected intermediate basis set, the basis subset comprising Ml bases for each layer l of the plurality of v layers; transmitting, to a base station (BS), for each layer l of the plurality of v layers, an indicator i1,6,l indicating indices of the Ml bases included in the selected basis subset; and based on the condition not being satisfied, transmitting, to the BS, an indicator i1,5 indicating indices of the N′ bases included in the selected intermediate basis set.