Codebook-based signal transmission/reception method in multi-antenna wireless communication system, and device for same
Disclosed are a codebook-based signal transmission and reception method in a multi-antenna wireless communication system and an apparatus therefor. Specifically, a method for transmitting or receiving a signal on the basis of a codebook by a terminal in a 2-dimensional multi-antenna wireless communication system comprises the steps of: receiving a channel state information reference signal (CSI-RS) through a multi-antenna port from a base station; and reporting channel state information to the base station, wherein the channel state information may include a precoding matrix indicator (PMI) for indicating a precoding matrix, the PMI may include a first PMI for selecting a set of precoding matrixes from the codebook and a second PMI for selecting one precoding matrix from the set of precoding matrixes.
1. A method for reporting, by a user equipment (UE), channel state information (CSI) in a wireless communication system, the method comprising:
receiving, from a base station (BS), a channel state information reference signal (CSI-RS) on multi-antenna ports; and
reporting, to the BS, channel state information, wherein:
the channel state information comprises a precoding matrix indicator (PMI) comprising a first PMI for selecting a set of precoding matrices from a codebook and a second PMI for selecting one precoding matrix from the set of precoding matrices,
the codebook comprises a precoding matrix generated based on a Kronecker product of a first matrix for a first-dimensional antenna port and a second matrix for a second-dimensional antenna port,
the first matrix is determined based on a first-dimensional index of the precoding matrix,
the second matrix is determined based on a second-dimensional index of the precoding matrix,
pairs of first-dimensional index and second-dimensional index of precoding matrices belonging to the set of precoding matrices are (x,y), (x+1,y), (x,y+1), and (x+1,y+1), and
the x and y are integers other than a negative number.
2. The method of claim 1 , wherein values of first-dimensional index and second-dimensional index of a precoding matrix belonging to the set of precoding matrices are determined based on the first PMI.
3. The method of claim 1 , wherein spacing between the set of precoding matrices consecutive in a first-dimensional direction is 2.
4. The method of claim 1 , wherein a factor for adjusting a phase between a first polarization antenna port and a second polarization antenna port in a cross-polarization antenna is determined based on the second PMI, and
wherein the factor is 1,
exp
(
j
π
2
)
,
exp
(
j
2
π
2
)
or
exp
(
j
3
π
2
)
.
5. The method of claim 1 , further comprising receiving a method of configuring the set of precoding matrices, a number of antenna ports having identical polarization in a first dimension, a number of antenna ports having identical polarization in a second dimension, an oversampling factor used in the first dimension, and an oversampling factor used in the second dimension through a radio resource control (RRC) message.
6. The method of claim 1 , wherein a total number of precoding matrices forming the codebook is determined by a number of antenna ports having identical polarization in a first dimension, a number of antenna ports having identical polarization in a second dimension, an oversampling factor used in the first dimension and an oversampling factor used in the second dimension.
7. The method of claim 1 , wherein the first matrix comprises one or more columns selected from a discrete Fourier transform (DFT) matrix generated by an equation below:
D
(
mn
)
N
h
×
N
h
Q
h
=
1
N
h
e
j
2
π
(
m
-
1
)
(
n
-
1
)
N
h
Q
h
,
m
=
1
,
2
,
…
,
N
h
,
n
=
1
,
2
,
…
,
N
h
Q
h
[
Equation
]
wherein N h is a number of antenna ports having identical polarization in a first dimension and Q h is an oversampling factor used in the first dimension.
8. The method of claim 1 , wherein the second matrix comprises one or more columns selected from a discrete Fourier transform (DFT) matrix generated by an equation below:
D
(
mn
)
N
v
×
N
v
Q
v
=
1
N
v
e
j
2
π
(
m
-
1
)
(
n
-
1
)
N
v
Q
v
,
m
=
1
,
2
,
…
,
N
v
,
n
=
1
,
2
,
…
,
N
v
Q
v
[
Equation
]
wherein N v is a number of antenna ports having identical polarization in a second dimension and Q v is an oversampling factor used in the second dimension.
9. A method for receiving, by a base station (BS), channel state information (CSI) report in a wireless communication system, the method comprising:
transmitting, to a user equipment (UE), a channel state information reference signal (CSI-RS) on multi-antenna ports; and
receiving, from the UE, the CSI report, wherein:
the CSI report comprises a precoding matrix indicator (PMI) comprising a first PMI for selecting a set of precoding matrices from a codebook and a second PMI for selecting the precoding matrix from the set of precoding matrices,
the codebook comprises a precoding matrix generated based on a Kronecker product of a first matrix for a first-dimensional antenna port and a second matrix for a second-dimensional antenna port,
the first matrix is determined based on a first-dimensional index of the precoding matrix,
the second matrix is determined based on a second-dimensional index of the precoding matrix,
pairs of first-dimensional index and second-dimensional index of precoding matrices belonging to the set of precoding matrices are (x,y), (x+1,y), (x,y+1), and (x+1,y+1), and
the x and y are integers other than a negative number.
10. The method of claim 9 , wherein spacing between the set of precoding matrices consecutive in a first-dimensional direction is 2.
11. A terminal for reporting channel state information (CSI) in a wireless communication system, the terminal comprising:
a transmitter and a receiver to respectively transmit and receive a wireless signal; and
a processor operatively coupled to the transmitter and the receiver,
wherein the processor is configured to:
receive, from an evolved NodeB (eNB), a channel state information reference signal (CSI-RS) on a multi-antenna port; and
report, to the eNB, the channel state information, wherein:
the channel state information comprises a precoding matrix indicator (PMI) comprising a first PMI for selecting a set of precoding matrices from a codebook and a second PMI for selecting one precoding matrix from the set of precoding matrices,
the codebook comprises a precoding matrix generated based on a Kronecker product of a first matrix for a first-dimensional antenna port and a second matrix for a second-dimensional antenna port,
the first matrix is determined based on a first-dimensional index of the precoding matrix,
the second matrix is determined based on a second-dimensional index of the precoding matrix,
pairs of first-dimensional index and second-dimensional index of precoding matrices belonging to the set of precoding matrices are (x,y), (x+1,y), (x,y+1), and (x+1,y+1), and
the x and y are integers other than a negative number.