Method for transmitting orthogonal frequency division multiplexing signal on basis of RIS in wireless communication system, and device therefor
A method of a wireless device for transmitting an orthogonal frequency division multiplexing (OFDM) signal based on a reconfigurable intelligent surface (RIS) in a wireless communication system comprises determining a reflection coefficient related to the RIS, and generating the OFDM signal based on the RIS to which the determined reflection coefficient is applied.
1 . A method of a wireless device for transmitting an orthogonal frequency division multiplexing (OFDM) signal based on a reconfigurable intelligent surface (RIS) in a wireless communication system, the method comprising:
determining a reflection coefficient related to the RIS; and
generating the OFDM signal based on the RIS to which the determined reflection coefficient is applied,
wherein the RIS includes one or more RISs,
wherein the reflection coefficient is determined based on at least one of 1) a first coefficient, 2) a second coefficient, or 3) an inverse fast Fourier transform (IFFT) size of data related to the OFDM signal,
wherein the first coefficient is a value determined based on the data related to the OFDM signal, a modulation scheme related to the data, and a subcarrier index related to the OFDM signal, and
wherein the second coefficient is a value determined based on a specific index related to the OFDM signal.
2 . The method of claim 1 , wherein the specific index represents a time sample related to the IFFT size.
3 . The method of claim 2 , wherein the time sample is related to an OFDM symbol or a cyclic prefix (CP).
4 . The method of claim 3 , wherein the reflection coefficient related to the RIS satisfies the following equation:
R
(
k
,
n
)
=
X
(
k
)
e
j
2
π
k
n
N
N
,
n
=
N
-
P
,
…
,
N
-
1
[
Equation
]
where R(k, n) is the reflection coefficient related to the RIS, k is the subcarrier index, n is the specific index, X(k) is the first coefficient,
e
j
2
π
k
n
N
is the second coefficient, N is the IFFT size of the data related to the OFDM signal, and P is a length of the CP.
5 . The method of claim 1 , wherein the reflection coefficient related to the RIS includes one or more reflection coefficients related to the one or more RISs.
6 . The method of claim 5 , wherein, based on the one or more RISs including two or more RISs configured to each of subcarriers related to the OFDM signal, the same reflection coefficient is applied to the two or more RISs configured to each of the subcarriers related to the OFDM signal.
7 . The method of claim 1 , wherein, based on the OFDM signal being related to a plurality of antennas of the wireless device,
the reflection coefficient is determined based on at least one of 1) the first coefficient, 2) the second coefficient, 3) the IFFT size of the data related to the OFDM signal, or 4) a precoding vector related to the plurality of antennas.
8 . The method of claim 7 , wherein the reflection coefficient related to the RIS is determined for each of the plurality of antennas.
9 . The method of claim 8 , wherein the reflection coefficient related to the RIS satisfies the following equation:
R
p
(
k
,
n
)
=
v
p
(
k
)
X
(
k
)
e
j
2
π
k
n
N
N
,
n
=
N
-
P
,
…
,
N
-
1
[
Equation
]
where R p (k, n) is the reflection coefficient related to the RIS, k is the subcarrier index, n is the specific index, p is an antenna index, X(k) is the first coefficient,
e
j
2
π
k
n
N
is the second coefficient, N is the IFFT size of the data related to the OFDM signal, P is a length of a cyclic prefix (CP), and v p (k) is the precoding vector.
10 . A wireless device transmitting an orthogonal frequency division multiplexing (OFDM) signal based on a reconfigurable intelligent surface (RIS) in a wireless communication system, the wireless device comprising:
one or more transceivers including the RIS, the one or more transceivers including a reflection coefficient setting unit configured to set a reflection coefficient applied to the RIS;
one or more processors configured to control the one or more transceivers; and
one or more memories operably connectable to the one or more processors,
wherein the one or more memories are configured to store instructions that allow the one or more processors to perform operations based on being executed by the one or more processors,
wherein the operations comprise:
determining the reflection coefficient related to the RIS; and
generating the OFDM signal based on the RIS to which the determined reflection coefficient is applied,
wherein the RIS includes one or more RISs,
wherein the reflection coefficient is determined based on at least one of 1) a first coefficient, 2) a second coefficient, or 3) an inverse fast Fourier transform (IFFT) size of data related to the OFDM signal,
wherein the first coefficient is a value determined based on the data related to the OFDM signal, a modulation scheme related to the data, and a subcarrier index related to the OFDM signal, and
wherein the second coefficient is a value determined based on a specific index related to the OFDM signal.
11 . The wireless device of claim 10 , wherein the wireless device is a base station (BS) or a user equipment (UE).
12 . A device comprising:
one or more memories; and
one or more processors operably connected to the one or more memories,
wherein the one or more memories are configured to store instructions that allow the one or more processors to perform operations based on being executed by the one or more processors,
wherein the operations comprise:
determining a reflection coefficient related to a reconfigurable intelligent surface (RIS); and
generating an orthogonal frequency division multiplexing (OFDM) signal based on the RIS to which the determined reflection coefficient is applied,
wherein the RIS includes one or more RISs,
wherein the reflection coefficient is determined based on at least one of 1) a first coefficient, 2) a second coefficient, or 3) an inverse fast Fourier transform (IFFT) size of data related to the OFDM signal,
wherein the first coefficient is a value determined based on the data related to the OFDM signal, a modulation scheme related to the data, and a subcarrier index related to the OFDM signal, and
wherein the second coefficient is a value determined based on a specific index related to the OFDM signal.