Method and apparatus for transmitting and receiving reference signal in wireless communication system

A user equipment (UE) configured to operate in a wireless communication system, the UE comprising:

• a radio frequency unit;
• and
• a processor configured to functionally couple to the radio frequency unit,
• wherein the processor is further configured to:
• receive, from a base station, a demodulation reference signal (DMRS) configured based on a specific pattern,
• wherein the demodulation reference signal is transmitted based on (i) a specific antenna port and (ii) one or two time-axis symbols on which at least one other demodulation reference signal based on another antenna port is transmitted,
• wherein the demodulation reference signal is mapped to the one or two time-axis symbols based on a code division multiplexing (CDM) related to the specific pattern,
• wherein the CDM includes at least one of a first CDM on a frequency axis or a second CDM on a time axis, and
• decode the data using the demodulation reference signal,
• wherein, based on that a phase tracking reference signal (PTRS) is transmitted, a number of orthogonal cover codes (OCCs) applied to the second CDM is limited to one, and
• wherein, based on that only one OCC related to the second CDM is applied, the demodulation reference signal and the at least one other demodulation reference signal are mapped to two time-axis symbols based on a frequency division multiplexing (FDM).