Codebook-based signal transmission and reception method in multi-antenna wireless communication system and apparatus therefor
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 determining one precoding matrix applied to a multi-layer from the set of precoding matrixes, the precoding matrix may be configured by a precoding vector applied to each layer, and the precoding vector may be determined in the set of precoding vectors determined by the first PMI.
1. A method for a user equipment to transmit/receive a signal based on a codebook in a two dimensional multi-antenna wireless communication system, the method comprising:
receiving a channel state information reference signal (CSI-RS) from an eNB through a multi-antenna port; and
reporting channel state information to the eNB,
wherein the channel state information comprises a precoding matrix indicator (PMI) for indicating a precoding matrix,
wherein the PMI comprises a first PMI for selecting a first precoder from a first codebook and a second PMI for selecting a second precoder from a second codebook, wherein the first codebook has a 2-dimensional form including a first dimension and a second dimension,
wherein the first precoder comprises a set of precoding vectors,
wherein pair patterns of a first-dimensional index and a second-dimensional index of precoding vectors included in the set of precoding vectors includes a pattern of (x,y), (x+2,y), (x+1,y+1) and (x+3,y+1),
wherein the x and y are integers other than a negative number,
wherein the second precoder is related to a precoding vector selection within the set of precoding vectors,
wherein each pair pattern corresponding to the first and second dimensional indices is related to a number of feedback bits of the second precoder corresponding to the vector precoding selection,
wherein a specific precoding matrix is determined based on a product of the first precoder and the second precoder,
wherein the specific precoding matrix comprises one or more precoding vectors, and
wherein each of the one or more precoding vectors included in the specific precoding matrix is applied to each layer of plural layers.
2. The method of claim 1 , wherein, in a case of a 3-layer or 4-layer transmission:
two specific precoding vectors selected based on the precoding vector selection are orthogonal for each other, and
indexes corresponding to a first-dimension of the two specific precoding vectors are each spaced apart by a multiple of a specific value.
3. The method of claim 1 , wherein:
a precoding vector included the set of precoding vectors is generated based on a Kronecker product of a first vector for a first-dimensional antenna port and a second vector for a second-dimensional antenna port, and
the first vector is specified by the first-dimensional index of the precoding vector, and the second vector is specified by the second-dimensional index of the precoding vector.
4. The method of claim 3 , wherein the first vector 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.
5. The method of claim 3 , wherein the second vector 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 the second dimension, and Q_v is an oversampling factor used in the second dimension.
6. The method of claim 1 , wherein in case of layer 2, a pair of first-dimensional indexes of the set of precoding vectors included in the first precoder is (0,0), (1,1), (2,2), (3,3), (0,1), (0,2), (0,3), and (1,2),
wherein the first-dimensional indexes included in the pair correspond to each the plural layers.
7. The method of claim 1 , wherein a selection vector included in the second precoder is multiplied by a rotation coefficient when a precoding vector included in the set of precoding vectors overlaps with a precoding vector included in a specific set of precoding vectors adjacent with the set of precoding vectors.
8. The method of claim 1 , wherein the pair patterns of the first-dimensional index and the second-dimensional index of the precoding vectors included in the set of precoding vectors further includes at least one of (i) a pattern of (x,y), (x+1,y), (x+2,y), and (x+3,y) or (ii) a pattern of (x,y), (x+1,y), (x,y+1), and (x+1,y+1).
9. The method of claim 1 , in a case of 5 or 6-layer transmission,
wherein three specific precoding vectors are selected based on the precoding vector selection, and
wherein the three specific precoding vectors are orthogonal for each other.
10. A method for an eNB to transmit/receive a signal based on a codebook in a two dimensional multi-antenna wireless communication system, the method comprising:
transmitting a channel state information reference signal (CSI-RS) to a user equipment through a multi-antenna port; and
receiving channel state information from the user equipment,
wherein the channel state information comprises a precoding matrix indicator (PMI) for indicating a precoding matrix,
wherein the PMI comprises a first PMI for selecting a first precoder from a first codebook and a second PMI for selecting a second precoder from a second codebook,
wherein the first codebook has a 2-dimensional form including a first dimension and a second dimension,
wherein the first precoder comprises a set of precoding vectors,
wherein pair patterns of a first-dimensional index and a second-dimensional index of precoding vectors included in the set of precoding vectors includes a pattern of (x,y), (x+2,y), (x+1,y+1) and (x+3,y+1),
wherein the x and y are integers other than a negative number,
wherein the second precoder is related to a precoding vector selection within the set of precoding vectors,
wherein each pair pattern corresponding to the first and second dimensional indices is related to a number of feedback bits of the second precoder corresponding to the vector precoding selection,
wherein a specific precoding matrix is determined based on a product of the first precoder and the second precoder,
wherein the specific precoding matrix comprises one or more precoding vectors, and
wherein each of the one or more precoding vectors included in the specific precoding matrix is applied to each layer of plural layers.
11. The method of claim 10 , wherein the pair patterns of the first-dimensional index and the second-dimensional index of the precoding vectors included in the set of precoding vectors further includes at least one of (i) a pattern of (x,y), (x+1,y), (x+2,y), and (x+3,y) or (ii) a pattern of (x,y), (x+1,y), (x,y+1), and (x+1,y+1).
12. The method of claim 10 , in a case of 5 or 6-layer transmission,
wherein three specific precoding vectors are selected based on the precoding vector selection, and
wherein the three specific precoding vectors are orthogonal for each other.