A method of a user equipment (UE) for a channel state information (CSI) feedback in a wireless communication system. The method comprises receiving, from a base station (BS), CSI feedback configuration information for the CSI feedback including a spatial channel information (SCI) indicator for each subband (SB), wherein the SCI indicator indicates a SCI associated with the downlink (DL) channel matrix; determining a CSI matrix HK,N comprising a dimension K×N based on the CSI feedback configuration information, where K indicates a number of SBs and N indicates a number of components of the SCI; identifying, based on the CSI matrix HK,N, the SCI indicator that indicates a first set of d basis vectors comprising a dimension K×1, a second set of d basis vectors comprising a dimension N×1, and a set of d coefficients, and transmitting, to the BS, the CSI feedback including the identified SCI indicator indicating the first set of d basis vectors, the second set of d basis vectors, and a set of d coefficients over an uplink channel.