Method for transmitting DMRS in wireless communication system supporting NB-IoT and apparatus therefor

A user equipment configured to transmit a narrow band (NB) physical uplink channel in a wireless communication system supporting Narrowband-Internet of Things (NB-IoT), the user equipment comprising:

• at least one transceiver;
• at least one processor;
• and
• at least one memory operably connectable to the at least one processor and storing instructions that, based on being executed by the at least one processor, perform operations comprising:
• determining, based on a number of at least one subcarrier in resource unit for the NB physical uplink channel being ‘1’, a binary phase shift keying (BPSK) or a quadrature phase shift keying (QPSK) as modulation scheme for the NB physical uplink channel;
• determining, based on the modulation scheme for the NB physical uplink channel, a phase rotation for each of one or more symbols;
• and
• transmitting, to a base station, the NB physical uplink channel on the one or more symbols based on the phase rotation.