A method for operating a communication device in a wireless communication system, according to the present embodiment, comprises the steps of: determining first information related to an aggregation level for a PDCCH and second information related to a mother code size for a polar code, the aggregation level being related to a first level to a fifth level, the mother code size being related to a first size to a third size, and the second information being determined according to the first information; determining whether the first information is determined to be the third level; and generating a CRC block comprising a masking sequence of a first type, when the first information is considered to be determined to be the third level.