Method for transmitting demodulation reference signal in wireless communication system for supporting narrowband IoT, and device therefor

A method for transmitting, by a user equipment (UE), a demodulation reference signal (DMRS) in a wireless communication system supporting NB (Narrow-Band)-IoT (Internet of Things), the method comprising:

• generating a reference signal sequence used for a demodulation;
• mapping the reference signal sequence to at least one symbol;
• and
• transmitting, to a base station, the demodulation reference signal (DMRS) on the at least one symbol,
• wherein the reference signal sequence is generated when the number of subcarriers within a resource unit 6,
• wherein the resource unit is defined as consecutive SC-FDMA (Single Carrier-Frequency Division Multiplexing Access) symbols in a time domain and consecutive subcarriers in a frequency domain,
• wherein the number of indices of a base sequence used in a generation of the reference signal sequence is 14,
• wherein φ(0), φ(1), φ(2), φ(3), φ(4) and φ(5) in a first index of the base sequence are 1, 1, 1, 1, 3, and −3, respectively,
• wherein φ(0), φ(1), φ(2), φ(3), φ(4) and φ(5) in a second index of the base sequence are 1, 1, 3, 1, −3, and 3, respectively,
• wherein φ(0), φ(1), φ(2), φ(3), φ(4) and φ(5) in a third index of the base sequence are 1, −1, −1, −1, 1, and −3, respectively,
• wherein φ(0), φ(1), φ(2), φ(3), φ(4) and φ(5) in a fourth index of the base sequence are 1, −1, 3, −3, −1, and −1, respectively,
• wherein φ(0), φ(1), φ(2), φ(3), φ(4) and φ(5) in a fifth index of the base sequence are 1, 3, 1, −1, −1, and 3, respectively,
• wherein φ(0), φ(1), φ(2), φ(3), φ(4) and φ(5) in a sixth index of the base sequence are 1, −3, −3, 1, 3, and 1, respectively,
• wherein φ(0), φ(1), φ(2), φ(3), φ(4) and φ(5) in a seventh index of the base sequence are −1, −1, 1, −3, −3, and −1, respectively,
• wherein φ(0), φ(1), φ(2), φ(3), φ(4) and φ(5) in an eighth index of the base sequence are −1, −1, −1, 3, −3, and −1, respectively,
• wherein φ(0), φ(1), φ(2), φ(3), φ(4) and φ(5) in a ninth index of the base sequence are 3, −1, 1, −3, −3, and 3, respectively,
• wherein φ(0), φ(1), φ(2), φ(3), φ(4) and φ(5) in a tenth index of the base sequence are 3, −1, 3, −3, −1, and 1, respectively,
• wherein φ(0), φ(1), (p(2), (p(3), φ(4) and φ(5) in an eleventh index of the base sequence are 3, −3, 3, −1, 3, and 3, respectively,
• wherein φ(0), φ(1), φ(2), φ(3), φ(4) and φ(5) in a twelfth index of the base sequence are −3, 1, 3, 1, −3, and −1, respectively,
• wherein φ(0), φ(1), (p(2), (p(3), φ(4) and φ(5) in a thirteenth index of the base sequence are −3, 1, −3, 3, −3, and −1, respectively,
• wherein φ(0), φ(1), φ(2), φ(3), φ(4) and φ(5) in a fourteenth index of the base sequence are −3, 3, −3, 1, 1, and −3, respectively.

A User Equipment (UE) for transmitting a demodulation reference signal (DMRS) in a wireless communication system supporting NB (Narrow-Band)-IoT (Internet of Things), the UE comprising:

• a Radio Frequency (RF) unit for transmitting and receiving a radio signal;
• and
• a processor for controlling the RF unit,
• wherein the processor controls to:
• generate a reference signal sequence used for a demodulation;
• map the reference signal sequence to at least one symbol;
• and
• transmit, to the base station, the demodulation reference signal (DMRS) on the at least one symbol,
• wherein the reference signal sequence is generated when the number of subcarriers within a resource unit is 1,
• wherein the resource unit is defined as consecutive SC-FDMA (Single Carrier-Frequency Division Multiplexing Access) symbols in a time domain and consecutive subcarriers in a frequency domain,
• wherein the reference signal sequence is generated using a gold sequence generated based on an m-sequence, and
• wherein the gold sequence is initialized with cinit=35.