A method for operating a user equipment in a wireless communication is provided as an embodiment of the present invention. The method may include: receiving modulation and coding scheme (MCS) information for each of two or more codewords from a base station (BS); determining a demodulation reference signal (DMRS) antenna port to which a phase tracking reference signal (PTRS) antenna port is mapped based on the MCS information; and receiving a PTRS based on the DMRS antenna port, wherein a DMRS antenna port with the lowest index among one or more DMRS antenna ports included in a codeword with the highest MCS among the two or more codewords may be determined as the DMRS antenna port.