A user equipment, UE, for a channel state information, CSI, feedback in an advanced communication system, the UE comprising: a transceiver; and at least one processor coupled with the transceiver and configured to: receive CSI feedback configuration information from a base station, identify a first parameter, a second parameter, a third parameter and a fourth parameter corresponding to combining coefficients based on a linear combination, LC, codebook for combination of at least two beams, and transmit CSI including the first parameter, the second parameter, the third parameter and the fourth parameter to the base station, and wherein a precoder is identified based on the LC codebook and the first parameter, the second parameter, the third parameter and the fourth parameter, wherein the first parameter is associated with indices for the at least two beams, wherein the second parameter is an amplitude value of the combining coefficients which are associated with a wideband of a beam and the third parameter is an amplitude value of the combining coefficients which are associated with at least one subband of the beam, and wherein the fourth parameter is associated with a phase value of the combining coefficients which are associated with the at least one subband of the beam. a transceiver; and at least one processor coupled with the transceiver and configured to: receive CSI feedback configuration information from a base station, identify a first parameter, a second parameter, a third parameter and a fourth parameter corresponding to combining coefficients based on a linear combination, LC, codebook for combination of at least two beams, and transmit CSI including the first parameter, the second parameter, the third parameter and the fourth parameter to the base station, and wherein a precoder is identified based on the LC codebook and the first parameter, the second parameter, the third parameter and the fourth parameter, wherein the first parameter is associated with indices for the at least two beams, wherein the second parameter is an amplitude value of the combining coefficients which are associated with a wideband of a beam and the third parameter is an amplitude value of the combining coefficients which are associated with at least one subband of the beam, and wherein the fourth parameter is associated with a phase value of the combining coefficients which are associated with the at least one subband of the beam. receive CSI feedback configuration information from a base station, identify a first parameter, a second parameter, a third parameter and a fourth parameter corresponding to combining coefficients based on a linear combination, LC, codebook for combination of at least two beams, and transmit CSI including the first parameter, the second parameter, the third parameter and the fourth parameter to the base station, and wherein a precoder is identified based on the LC codebook and the first parameter, the second parameter, the third parameter and the fourth parameter, wherein the first parameter is associated with indices for the at least two beams, wherein the second parameter is an amplitude value of the combining coefficients which are associated with a wideband of a beam and the third parameter is an amplitude value of the combining coefficients which are associated with at least one subband of the beam, and wherein the fourth parameter is associated with a phase value of the combining coefficients which are associated with the at least one subband of the beam. <EOS>