The present disclosure provides a method for transmitting and receiving in a wireless communication system and an apparatus therefore. Specifically, in a wireless communication system according to an embodiment of the present disclosure, there is provided a method for transmitting and receiving a signal by a receiving apparatus, the method includes receiving, from a transmitting apparatus, signals modulated based on a differential phase shift keying (DPSK) method through a plurality of reception paths, calculating a differential value in each reception path of the plurality of reception paths based on the received signals, and calculating reliability for the received signals, in which the reliability is proportional to a real value of a sum of the differential values in each reception path of the plurality of reception paths.