The method of UE for CSI reporting comprises receiving a higher layer signaling including CBSR information; determining a bitmap sequence B based on the CBSR information, wherein the bitmap sequence B includes a first bitmap sequence B1 and a second bitmap sequence B2; determining the first bitmap sequence B1 and the second bitmap sequence B2 based on the bitmap sequence B; identifying, based on the first bitmap sequence B1 and the second bitmap sequence B2, a restriction on P beam groups out of Q beam groups G(r1,r2) for the CSI reporting; generating a CSI report based on the P beam groups with the identified restriction for the CSI reporting and remaining Q minus P beam groups without any restrictions for the CSI reporting; and transmitting the CSI report to the BS. The remaining beam groups are determined as the Q beam groups G(r1,r2) minus the P beam groups.