The disclosure relates to a pre-5th-generation (5G) or 5G communication system to be provided for supporting higher data rates beyond 4th-generation (4G) communication system such as long term evolution (LTE). An operating method of a user equipment (UE) in a communication system includes performing radio resource control (RRC) signaling with a base station, determining a code rate based on an RRC configuration according to the RRC signaling, and determining a size of data using the code rate.