Method and apparatus for performing DAS-based positioning
Proposed is an operation method for a first device ( 100 ) in a wireless communication system. The method may comprise the steps of: receiving a first positioning reference signal (PRS) from a second device ( 200 ), on the basis of a first antenna ( 106 - 1 ), a second antenna ( 106 - 2 ), and a third antenna ( 106 - 3 ); obtaining a first time difference, on the basis of a first reception time at which the first PRS is received on the basis of the first antenna ( 106 - 2 ) and a second reception time at which the first PRS is received on the basis of the second antenna ( 106 - 2 ); obtaining a second time difference, on the basis of a third reception time at which the first RPS is received on the basis of the third antenna ( 106 - 3 ) and the first reception time; and obtaining the location of the first device ( 100 ), on the basis of the first time difference and the second time difference.
1. A method for performing, by a first device, wireless communication, the method comprising:
receiving a first positioning reference signal (PRS) from a second device based on a first antenna, a second antenna, and a third antenna;
obtaining a first time difference based on a first reception time where the first PRS is received based on the first antenna and a second reception time where the first PRS is received based on the second antenna;
obtaining a second time difference based on a third reception time where the first PRS is received based on the third antenna and the first reception time; and
obtaining a position of the first device based on the first time difference and the second time difference,
wherein the first device includes the first antenna, the second antenna, and the third antenna.
2. The method of claim 1 , wherein the position of the first device is obtained based on a following equation:
RSTD i m,n =√{square root over (( x RSU i −x m ) 2 +( y RSU i −y m ) 2 )}/ c −√{square root over (( x RSU i −x n ) 2 +( y RSU i −y n ) 2 )}/ c
RSTD i m,k =√{square root over (( x RSU i −x m ) 2 +( y RSU i −y m ) 2 )}/ c −√{square root over (( x RSU i −x k ) 2 +( y RSU i −y k ) 2 )}/ c
wherein the RSTD i m,n represents the first time difference,
wherein the RSTD i m,k represents the second time difference,
wherein the x RSUi and the y RSU i represents coordinates of the second device,
wherein the x m and the y m represents coordinates of the first antenna,
wherein the x n and the y n represents coordinates of the second antenna,
wherein the x k and the y k represents coordinates of the third antenna,
wherein the C represents a speed of light, and
wherein the position of the first device is obtained based on the coordinates of the first antenna.
3. The method of claim 2 , wherein the x n and the y n is expressed based on the coordinates of the first antenna, and
wherein the x k and the y k is expressed based on the coordinates of the first antenna.
4. The method of claim 2 , wherein the position of the first device is obtained based on a position of at least one of the first antenna, the second antenna, and the third antenna.
5. The method of claim 4 , wherein the position of the first device is obtained based on a following equation:
( x Ri ,x Ri )=( x i ,y i )−( d i cos(θ i ), d i sin(θ i )),
wherein the x Ri and the y Ri represents coordinates of the first device obtained based on the (x i , y i ),
wherein the x i and the y i represents coordinates of at least one of the first antenna, the second antenna, and the third antenna,
wherein the d i represents a distance between the (x Ri , y Ri ) and the (x i , y i ),
wherein the θ i represents an angle between a reference direction of an axis passing through the (x Ri , y Ri ) and a direction of a straight line passing the (x i , y i ) from the (x Ri , y Ri ), and
wherein the position of the first device is obtained based on the coordinates of the first device.
6. The method of claim 4 , wherein the position of the first device is obtained based on a following equation:
( x Ri ,y Ri )=( x i ,y i )−( d i cos(θ i ) d i sin(θ i )),
( x R ,y R )=Σβ Ri ·( x Ri ,y Ri ),
wherein the x R and the y R represents an estimate of the coordinates of the first device,
wherein the x Ri and the y Ri represents first reference position, second reference position, or third reference position of the first device based on estimate of coordinates of each of the first antenna, the second antenna, and the third antenna,
wherein the β Ri represents first weighting factor, second weighting factor, or third weighting factor related to each of the first reference position, the second reference position, or the third reference position,
wherein the x i and the y i represents the estimate of coordinates of each of the first antenna, the second antenna, and the third antenna,
wherein the d i represents a distance between the position of the first device and a position of each of the first antenna, the second antenna, and the third antenna,
wherein the θ i represents an angle between a reference direction of an axis passing through the (x Ri , y Ri ) and a direction of a straight line passing the (x i , y i ) from the (x Ri , y Ri ), and
wherein the position of the first device is obtained based on the estimate of the coordinates of the first device.
7. The method of claim 6 , wherein a sum of the first weighting factor, the second weighting factor, and the third weighting factor is 1.
8. The method of claim 6 , wherein the first weighting factor, the second weighting factor, and the third weighting factor are real numbers between greater than or equal to 0 and smaller than or equal to 1.
9. The method of claim 6 , wherein the first weighting factor, the second weighting factor, and the third weighting factor are related to a receiving signal quality of the first PRS, related to each obtainment of the first reference position, the second reference position, and the third reference position.
10. The method of claim 1 , wherein the first device is a vehicle including the first antenna, the second antenna, and the third antenna.
11. The method of claim 1 , wherein the second device is a base station or a road side unit (RSU).
12. The method of claim 1 , further comprising:
receiving a second PRS from a third device;
receiving a third PRS from a fourth device;
obtaining a third time difference based on the first reception time and a fourth reception time where the second PRS is received based on the first antenna;
obtaining a fourth time difference based on the second reception time and a fifth reception time where the second PRS is received based on the second antenna;
obtaining a fifth time difference based on the first reception time and a sixth reception time where the third PRS is received based on the first antenna;
obtaining a sixth time difference based on the second reception time and a seventh reception time where the third PRS is received based on the second antenna; and
obtaining the position of the first device based on the third time difference, the fourth time difference, the fifth time difference, and the sixth time difference.
13. The method of claim 12 , wherein the position of the first device is obtained based on a following equation:
RSTD i,j m −RSTD i,j n =(τ RSU i m −τ RSU i m )−(τ RSU i n −τ RSU j n )
RSTD i,k m −RSTD i,k n =(τ RSU i m −τ RSU k m )−(τ RSU i n −τ RSU j n )
τ RSU i m =√{square root over (( x m −x RSU i ) 2 +( y m −y RSU i ) 2 )}/ c
τ RSU j m =√{square root over (( x m −x RSU j ) 2 +( y m −y RSU i ) 2 )}/ c
τ RSU k m =√{square root over (( x m −x RSU k ) 2 +( y m −y RSU k ) 2 )}/ c
τ RSU i n =√{square root over (( x n −x RSU i ) 2 +( y n −y RSU i ) 2 )}/ c
τ RSU j n =√{square root over (( x n −x RSU i ) 2 +( y n −y RSU j ) 2 )}/ c
τ RSU k n =√{square root over (( x n −x RSU k ) 2 +( y m −y RSU k ) 2 )}/ c
wherein the RSTD i,j m represents the third time difference,
wherein the RSTD i,j n represents the fourth time difference,
wherein the RSTD i,k m represents the fifth time difference,
wherein the RSTD i,k n represents the sixth time difference,
wherein the τ RSU i m represents the first reception time,
wherein the τ RSU j m represents the fourth reception time,
wherein the τ RSU k m represents the sixth reception time,
wherein the τ RSU i n represents the second reception time,
wherein the τ RSU j n represents the fifth reception time,
wherein the τ RSU k n represents the seventh reception time,
wherein the x m and the y m represents coordinates of the first antenna,
wherein the x n and the y n represents coordinates of the second antenna,
wherein the x RSUi and the y RSU i represents coordinates of the second device,
wherein the x RSUj and the y RSUj represents coordinates of the third device,
wherein the x RSU k and the y RSU k represents coordinates of the fourth device,
wherein the c represents a speed of light, and
wherein the position of the first device is obtained based on the coordinates of the first antenna and the coordinates of the second antenna.
14. A first device for performing wireless communication, the first device comprising:
one or more memories storing instructions;
one or more transceivers; and
one or more processors connected to the one or more memories and the one or more transceivers, wherein the one or more processors execute the instructions to:
receive a first positioning reference signal (PRS) from a second device based on a first antenna, a second antenna, and a third antenna;
obtain a first time difference based on a first reception time where the first PRS is received based on the first antenna and a second reception time where the first PRS is received based on the second antenna;
obtain a second time difference based on a third reception time where the first PRS is received based on the third antenna and the first reception time; and
obtain a position of the first device based on the first time difference and the second time difference,
wherein the first device includes the first antenna, the second antenna, and the third antenna.
15. A device adapted to control a first user equipment (UE), the device comprising:
one or more processors; and
one or more memories operably connectable to the one or more processors and storing instructions, wherein the one or more processors execute the instructions to:
receive a first positioning reference signal (PRS) from a second UE based on a first antenna, a second antenna, and a third antenna;
obtain a first time difference based on a first reception time where the first PRS is received based on the first antenna and a second reception time where the first PRS is received based on the second antenna;
obtain a second time difference based on a third reception time where the first PRS is received based on the third antenna and the first reception time; and
obtain a position of the first UE based on the first time difference and the second time difference,
wherein the first UE includes the first antenna, the second antenna, and the third antenna.