The present disclosure relates to a method of transmitting Radio Link Control (RLC) status reports by a user equipment (UE) in a wireless communication system. In particular, the method includes the steps of: configuring a Packet Data Convergence Protocol (PDCP) entity associated with two or more RLC entities, wherein the PDCP entity receives duplicated PDCP Protocol Data Units (PDUs) from the two or more RLC entities; and based on the PDCP entity successfully receiving a PDCP PDU from at least one of the two or more RLC entities, transmitting RLC status reports related to a successful reception of a RLC Service Data Unit (SDU) including the PDCP PDU to all of peer RLC entities of the two or more RLC entities.