Method for estimating distance using wireless carrier signal phase measurement

A user equipment comprising:

• a communicator;
• and
• a processor,
• wherein the processor is configured to perform a process of receiving a first reference signal from a first transmitter, a process of acquiring phase information depending on carrier frequencies of the first reference signal and the second reference signal based on received data of the first reference signal measured at a plurality of sample times and received data of the second reference signal measured at the plurality of sample times, and a process of outputting information about a difference between a travel distance of the first reference signal and a travel distance of the second reference signal based on the phase information depending on the carrier frequencies, and
• wherein the process of acquiring of the phase information comprises:
• a process of acquiring a first sample vector based on the received data of the first reference signal, acquiring a second sample vector based on the received data of the second reference signal,
• a process of calculating a first phase vector and a second phase vector by performing an inner product operation of a discrete Fourier transform (DFT) coefficient vector for a DFT operation with respect to each of the first sample vector and the second sample vector, and
• a process of acquiring the phase information from a conjugate multiplication of the first phase vector and the second phase vector.

A positioning reference signal transmission method performed by a plurality of transmitters, the method comprising:

• transmitting, by a first transmitter, a first reference signal;
• and
• transmitting, by a second transmitter, a second reference signal,
• wherein the first reference signal includes at least one subcarrier signal included in a first subcarrier group, and the second reference signal includes at least one subcarrier signal included in a second subcarrier group,
• wherein each of the at least one subcarrier signal is generated by a sequence that generates a continuous sine wave at the boundary of the symbols comprising cyclic prefix (CP), and
• wherein a complex signal component of each of the subcarriers included in the first subcarrier group and a complex signal component of each of the subcarriers included in the second subcarrier group have a conjugate relation.