A method and apparatus in a wireless communication system supporting shared spectrum channel access is provided. The method and apparatus comprises: receiving a set of downlink channels supporting the shared spectrum channel access; identifying, a window for SS/PBCH block transmission, a bitmap for SS/PBCH blocks (ssb-PositionsInBurst), and a parameter for QCL assumption Q; determining, based on the identified window for the SS/PBCH block transmission, the identified bitmap for the ssb-PositionsInBurst, and the identified parameter for the QCL assumption Q, a SS/PBCH block as one of: a first set of SS/PBCH blocks assumed to be transmitted by the BS, or a second set of SS/PBCH blocks not transmitted by the BS; determining a set of resources that is not available for at least one PDSCH as overlapped with the first set of SS/PBCH blocks; and receiving the at least one PDSCH based on resource other than the determined set of resources.