Method and device for feeding back channel state information in multi-input multi-output system
A method and device for feeding back Channel State Information (CSI) in a multi-input multi-output system are provided. In the method, User Equipment (UE) feeds back CSI comprising codebook index information to an evolved Node B (eNodeB). The codebook index information may include a first type of codebook index set I and a second type of codebook index set J, where a combination of the first type of index set I and the second type of index set J is used for indicating a precoding matrix U, and the precoding matrix U is an N t ×r matrix and is composed of at least Q×r basic vectors having a dimension of N t /Q. The basic vectors are columns extracted from a matrix B composed of M columns of N t /Q-dimensional vectors.
1. A method for feeding back Channel State Information (CSI) in a multi-input multi-output system, the method comprising:
feeding back, by a User Equipment (UE), CSI comprising codebook index information to an evolved Node B (eNodeB), wherein
the codebook index information comprises: a first type of codebook index set I and a second type of codebook index set J; a combination of the first type of index set I and the second type of index set J is used for indicating a precoding matrix U, and the precoding matrix U is an N t ×r matrix, where N t represents a total number of ports or a total number of antennas and r represents a number of transmission layers; the precoding matrix U is composed of at least Q×r basic vectors having a dimension of N t /Q, where Q≥2, r≥1, and Q and r are both positive integers; the basic vectors are columns extracted from a matrix B composed of M columns of N t /Q-dimensional vectors, where M is a positive integer;
a union of the first type of index set I and the second type of index set J comprises codebook indication information i 1 , i 2 and i 3 ;
the codebook indication information i 1 is used for representing selection information of K matrixes W i 1 1 . . . W i 1 k , where K is a positive integer, each column of the K matrixes W i 1 1 . . . W i 1 k is extracted from column vectors comprised in the matrix B; i 3 is used for representing a matrix W i 1 1 selected from the K matrixes; i 2 is used for representing information of one or more basic vectors extracted from the matrix W i 1 1 and used to construct the precoding matrix U.
2. The method as claimed in claim 1 , wherein the precoding matrix U meets a model:
U
=
[
v
0
β
v
1
]
or
U
=
[
v
0
′
α
v
1
′
β
v
2
′
αβ
v
3
′
]
or
U
=
[
v
0
v
2
β
v
1
-
β
v
3
]
or
U
=
[
v
0
′
v
4
′
α
v
1
′
α
v
5
′
β
v
2
′
-
β
v
6
′
αβ
v
3
′
-
αβ
v
7
′
]
,
where, vectors v 0 , v 1 , v 2 and v 3 are vectors having a dimension of N t /2×1 vectors v′ 0 , v′ 1 , v′ 2 , v′ 3 , v′ 4 , v′ 5 , v′ 6 and v′ 7 are vectors having a dimension of N t /4×1, α=e jθ 1 , and β=e jθ 2 , where 0≤θ 1 ≤2π, 0≤θ 2 ≤2π.
3. The method as claimed in claim 2 , wherein for the codebook model
U
=
[
v
0
′
α
v
1
′
β
v
2
′
αβ
v
3
′
]
or
U
=
[
v
0
′
v
4
′
α
v
1
′
α
v
5
′
β
v
2
′
-
β
v
6
′
αβ
v
3
′
-
αβ
v
7
′
]
,
at least one of the codebook indication information i 1 , i 2 and i 3 is further used to represent α information in the codebook model U;
or,
at least one of the codebook indication information i 1 , i 2 and i 3 is further used to represent β information in the codebook model U.
4. The method as claimed in claim 2 , wherein for the model
U
=
[
v
0
v
2
β
v
1
-
β
v
3
]
,
the codebook indication information i 3 comprises two pieces of sub-information i 3 (1) and i 3 (2);
wherein i 3 (1) is used for representing information of a matrix W i 1 i 3 (1) from which vectors v 0 and v 2 are extracted; and i 3 (2) is used for representing information of a matrix W i 1 i 3 (2) from which vectors v 1 and v 3 are extracted; or,
the i 3 (1) is used for representing information of a matrix W i 1 i 3 (1) from which vectors v 0 and v 1 are extracted; and i 3 (2) is used for representing information of a matrix W i 1 i 3 (2) from which vectors v 2 and v 3 are extracted;
or,
for the model
U
=
[
v
0
′
α
v
1
′
β
v
2
′
αβ
v
3
′
]
,
the codebook indication information i 3 comprises two pieces of sub-information i 3 (1) and i 3 (2);
wherein i 3 (1) is used for representing information of a matrix W i 1 i 3 (1) from which vectors v′ 0 and v′ 1 are extracted; and i 3 (2) is used for representing information of a matrix W i 1 i 3 (2) from which vectors v′ 2 and v′ 3 are extracted; or,
i 3 (1) is used for representing information of a matrix W i 1 i 3 (1) from which vectors v′ 0 and v′ 2 are extracted; and i 3 (2) is used for representing information of a matrix W i 1 i 3 (2) from which vectors v′ 1 and v′ 3 are extracted;
or,
for the model
U
=
[
v
0
′
v
4
′
α
v
1
′
α
v
5
′
β
v
2
′
-
β
v
6
′
αβ
v
3
′
-
αβ
v
7
′
]
,
the codebook indication information i 3 comprises four pieces of sub-information i 3 (1), i 3 (2), i 3 (3) and i 3 (4), wherein i 3 (1) is used for representing information of a matrix W i 1 i 3 (1) from which vectors v′ 0 and v′ 4 are extracted; i 3 (2) is used for representing information of a matrix W i 1 i 3 (2) from which vectors v′ 1 and i′ 5 are extracted; i 3 (3) is used for representing information of a matrix W i 1 i 3 (3) from which vectors v′ 2 and v′ 6 are extracted; i 3 (4) is used for representing information of a matrix W i 1 i 3 (4) from which vectors v′ 3 and v′ 7 are extracted.
5. The method as claimed in claim 4 , wherein for the model
U
=
[
v
0
v
2
β
v
1
-
β
v
3
]
or
U
=
[
v
0
′
α
v
1
′
β
v
2
′
αβ
v
3
′
]
,
i 3 (1)=i 3 (2); or, for the model
U
=
[
v
0
′
v
4
′
α
v
1
′
α
v
5
′
β
v
2
′
-
β
v
6
′
αβ
v
3
′
-
αβ
v
7
′
]
,
i 3 (1)=i 3 (2)=i 3 (3)=i 4 (4).
6. The method as claimed in claim 2 , wherein for the model
U
=
[
v
0
′
α
v
1
′
β
v
2
′
αβ
v
3
′
]
,
the codebook indication information i 2 comprises two pieces of sub-information i 2 (1) and i 2 (2);
wherein i 2 (1) is used for representing information of a basic vector extracted from the matrix W i 1 l for vectors v′ 0 and v′ 1 ; i 2 (2) is used for representing information of a basic vector extracted from the matrix W i 1 l′ for vectors v′ 2 and v′ 3 ; or,
i 2 (1) is used for representing information of a basic vector extracted from the matrix W i 1 l for vectors v′ 0 and v′ 2 ; i 2 (2) is used for representing information of a basic vector extracted from the matrix W i 1 l′ for vectors v′ 1 and v′ 3 ;
or,
for the model
U
=
[
v
0
v
2
β
v
1
-
β
v
3
]
,
the codebook indication information i 2 comprises two pieces of sub-information i 2 (1) and i 2 (2);
wherein i 2 (1) is used for representing information of a basic vector extracted from the matrix W i 1 l for vectors v 0 and v 2 ; i 2 (2) is used for representing information of a basic vector extracted from the matrix W i 1 l′ for vectors v 1 and v 3 ; or,
i 2 (1) is used for representing information of a basic vector extracted from the matrix W i 1 l for vectors v 0 and v 1 ; i 2 (2) is used for representing information of a basic vector extracted from the matrix W i 1 l′ for vectors v 2 and v 3 ;
or,
for the model
U
=
[
v
0
′
v
4
′
α
v
1
′
α
v
5
′
β
v
2
′
-
β
v
6
′
αβ
v
3
′
-
αβ
v
7
′
]
,
the codebook indication information i 2 comprises four pieces of sub-information i 2 (1), i 2 (2), i 2 (3) and i 2 (4);
wherein i 2 (1) is used for representing information of a basic vector extracted from the matrix W i 2 l for vectors v′ 0 and v′ 4 ; i 2 (2) is used for representing information of a basic vector extracted from the matrix W i 1 l′ for vectors v′ 1 and v′ 5 ; i 2 (3) is used for representing information of a basic vector extracted from the matrix W i 1 l″ for vectors v′ 2 and v′ 6 ; and i 2 (4) is used for representing information of a basic vector extracted from the matrix W i 1 l′″ for vectors v′ 3 and v′ 7 ;
or,
for the model
U
=
[
v
0
′
v
4
′
α
v
1
′
α
v
5
′
β
v
2
′
-
β
v
6
′
αβ
v
3
′
-
αβ
v
7
′
]
,
the codebook indication information i 2 comprises four pieces of sub-information i 2 (1), i 2 (2), i 2 (3) and i 2 (4);
wherein i 2 (1) is used for representing information of a basic vector extracted from the matrix W i 1 l for vectors v′ 0 and v′ 1 ; i 2 (2) is used for representing information of a basic vector extracted from the matrix W i 1 l′ for vectors v′ 2 and v′ 3 ; i 2 (3) is used for representing information of a basic vector extracted from the matrix W i 1 l″ for vectors v′ 4 and v′ 5 ; and i 2 (4) is used for representing information of a basic vector extracted from the matrix W i 1 l′″ for vectors v′ 6 and v′ 7 ; or,
i 2 (1) is used for representing information of a basic vector extracted from the matrix W i 1 l for vectors v′ 0 and v′ 2 ; i 2 (2) is used for representing information of a basic vector extracted from the matrix W i 1 l′ for vectors v′ 1 and v′ 3 ; i 2 (3) is used for representing information of a basic vector extracted from the matrix W i 1 l″ for vectors v′ 4 and v′ 6 ; and i 2 (4) is used for representing information of a basic vector extracted from the matrix W i 1 l′″ for vectors v′ 5 and v′ 7 .
7. The method as claimed in claim 6 , wherein for the model
U
=
[
v
0
′
α
v
1
′
β
v
2
′
αβ
v
3
′
]
or
U
=
[
v
0
v
2
β
v
1
-
β
v
3
]
,
i 2 (1)=i 2 (2); or, for the model
U
=
[
v
0
′
v
4
′
α
v
1
′
α
v
5
′
β
v
2
′
-
β
v
6
′
αβ
v
3
′
-
αβ
v
7
′
]
,
i 2 (1)=i 2 (2)=i 2 (3)=i 2 (4).
8. The method as claimed in claim 1 , wherein the first type of codebook index set I at least comprises i 1 and i 3 information; and the second type of codebook index set J at least comprises i 2 information; or,
the first type of codebook index set I at least comprises i 1 and i 2 information; and the second type of codebook index set J at least comprises i 3 information; or,
the first type of codebook index set I at least comprises i 1 information; and the second type of codebook index set J at least comprises i 2 and i 3 information.
9. The method as claimed in claim 1 , wherein the basic vectors composing the precoding matrix U are divided into N1 groups; the codebook indication information i 3 comprises N1 pieces of sub-information i 3 (1) . . . i 3 (N1) N1≥2 and is a positive integer; wherein i 3 (x) is used for representing information of a matrix W i 1 l x selected for an x th group of vectors from the K matrixes W i 1 1 . . . W i 1 k indicated by i 1 , where 2≤x≤N1.
10. The method as claimed in claim 9 , wherein i 3 (1) . . . i 3 (N1) have a linear relationship; when the CSI is reported, the UE at least reports one codebook indication information in i 3 (1) . . . i 3 (N1).
11. The method as claimed in claim 9 , wherein for the model
U
=
[
v
0
v
2
β
v
1
-
β
v
3
]
,
the codebook indication information i 3 comprises two pieces of sub-information i 3 (1) and i 3 (2);
wherein i 3 (1) is used for representing information of a matrix W i 1 i 3 (1) from which vectors v 0 and v 2 are extracted; and i 3 (2) is used for representing information of a matrix W i 1 i 3 (2) from which vectors v 1 and v 3 are extracted; or,
the i 3 (1) is used for representing information of a matrix W i 1 i 3 (1) from which vectors v 0 and v 1 are extracted; and i 3 (2) is used for representing information of a matrix W i 1 i 3 (2) from which vectors v 2 and v 3 are extracted;
or,
for the model
U
=
[
v
0
′
α
v
1
′
β
v
2
′
αβ
v
3
′
]
,
the codebook indication information i 3 comprises two pieces of sub-information i 3 (1) and i 3 (2);
wherein i 3 (1) is used for representing information of a matrix W i 1 i 3 (1) from which vectors v′ 0 and v′ 1 are extracted; and i 3 (2) is used for representing information of a matrix W i 1 i 3 (2) from which vectors v′ 2 and v′ 3 are extracted; or,
i 3 (1) is used for representing information of a matrix W i 1 i 3 (1) from which vectors v′ 0 and v′ 2 are extracted; and i 3 (2) is used for representing information of a matrix W i 1 i 3 (2) from which vectors v′ 1 and v′ 3 are extracted;
or,
for the model
U
=
[
v
0
′
v
4
′
α
v
1
′
α
v
5
′
β
v
2
′
-
β
v
6
′
αβ
v
3
′
-
αβ
v
7
′
]
,
the codebook indication information i 3 comprises four pieces of sub-information i 3 (1), i 3 (2), i 3 (3) and i 3 (4), wherein i 3 (1) is used for representing information of a matrix W i 1 i 3 (1) from which vectors v′ 0 and v′ 4 are extracted; i 3 (2) is used for representing information of a matrix W i 1 i 3 (2) from which vectors v′ 1 and v′ 5 are extracted; i 3 (3) is used for representing information of a matrix W i 1 i 3 (3) from which vectors v′ 2 and v′ 6 are extracted; i 3 (4) is used for representing information of a matrix W i 1 i 3 (4) from which vectors v′ 3 and v′ 7 are extracted.
12. The method as claimed in claim 1 , wherein the basic vectors composing the precoding matrix U are divided into N2 groups; the codebook indication information i 2 comprises N2 pieces of sub-information i 2 (1) . . . i 2 (N2) N2≥2; where i 2 (y) is used for representing information of one or more basic vectors extracted from a matrix W i 1 l y jointly indicated by i 1 and i 3 and used to construct the precoding matrix U, 2≤y≤N2.
13. The method as claimed in claim 12 , wherein i 2 (1) . . . i 2 (N2) have a linear relationship; when the CSI is reported, the UE at least reports one codebook indication information in i 2 (1) . . . i 2 (N2).
14. The method as claimed in claim 12 , wherein for the model
U
=
[
v
0
′
α
v
1
′
β
v
2
′
αβ
v
3
′
]
,
the codebook indication information i 2 comprises two pieces of sub-information i 2 (1) and i 2 (2);
wherein i 2 (1) is used for representing information of a basic vector extracted from the matrix W i 1 l for vectors v′ 0 and v′ 2 ; i 2 (2) is used for representing information of a basic vector extracted from the matrix W i 1 l′ for vectors v′ 2 and v′ 3 ; or,
i 2 (1) is used for representing information of a basic vector extracted from the matrix W i 1 l for vectors v′ 0 and v′ 2 ; i 2 (2) is used for representing information of a basic vector extracted from the matrix W i 1 l′ for vectors v′ 1 and v′ 3 ;
or,
for the model
U
=
[
v
0
v
2
β
v
1
-
β
v
3
]
,
the codebook indication information i 2 comprises two pieces of sub-information i 2 (1) and i 2 (2);
wherein i 2 (1) is used for representing information of a basic vector extracted from the matrix W i 1 l for vectors v 0 and v 2 ; i 2 (2) is used for representing information of a basic vector extracted from the matrix W i 1 l′ for vectors v 1 and v 3 ; or,
i 2 (1) is used for representing information of a basic vector extracted from the matrix W i 1 l for vectors v 0 and v 1 ; i 2 (2) is used for representing information of a basic vector extracted from the matrix W i 1 l′ for vectors v 2 and v 3 ;
or,
for the model
U
=
[
v
0
′
v
4
′
α
v
1
′
α
v
5
′
β
v
2
′
-
β
v
6
′
αβ
v
3
′
-
αβ
v
7
′
]
,
the codebook indication information i 2 comprises four pieces of sub-information i 2 (1), i 2 (2), i 2 (3) and i 2 (4);
wherein i 2 (1) is used for representing information of a basic vector extracted from the matrix W i 1 l for vectors v′ 0 and v′ 4 ; i 2 (2) is used for representing information of a basic vector extracted from the matrix W i 1 l′ for vectors v′ 1 and v′ 5 ; i 2 (3) is used for representing information of a basic vector extracted from the matrix W i 1 l″ for vectors v′ 2 and v′ 2 ; and i 2 (4) is used for representing information of a basic vector extracted from the matrix W i 1 l′″ for vectors v′ 3 and v′ 7 ;
or,
for the model
U
=
[
v
0
′
v
4
′
αv
1
′
αv
5
′
βv
2
′
-
βv
6
′
αβv
3
′
-
αβv
7
′
]
,
the codebook indication information i 2 comprises four pieces of sub-information i 2 (1), i 2 (2), i 2 (3) and i 2 (4);
wherein i 2 (1) is used for representing information of a basic vector extracted from the matrix W i 1 l for vectors v′ 0 and v′ 1 ; i 2 (2) is used for representing information of a basic vector extracted from the matrix W i 1 l′ for vectors v′ 2 and v′ 3 , i 2 (3) is used for representing information of a basic vector extracted from the matrix W i 1 l″ for vectors v′ 4 and v′ 5 ; and i 2 (4) is used for representing information of a basic vector extracted from the matrix W i 1 l′″ for vectors v′ 6 and v′ 7 ; or,
i 2 (1) is used for representing information of a basic vector extracted from the matrix W i 1 l for vectors v′ 0 and v′ 2 ; i 2 (2) is used for representing information of a basic vector extracted from the matrix W i 1 l′ for vectors v′ 1 and v′ 3 ; i 2 (3) is used for representing information of a basic vector extracted from the matrix W i 1 l″ for vectors v′ 4 and v′ 6 ; and i 2 (4) is used for representing information of a basic vector extracted from the matrix W i 1 l′″ for vectors v′ 5 and v′ 7 .
15. The method as claimed in claim 1 , where M columns of vectors composing the matrix B are Discrete Fourier Transformation (DFT) vectors.
16. A method for feeding back Channel State Information (CSI) in a multi-input multi-output system, the method comprising:
feeding back, by a User Equipment (UE), CSI comprising codebook index information to an evolved Node B (eNodeB), wherein
the codebook index information comprises: a first type of codebook index set I and a second type of codebook index set J; a combination of the first type of index set I and the second type of index set J is used for indicating a precoding matrix U; a union of the first type of index set I and the second type of index set J comprises codebook indication information i 1 , i 2 and i 3 ; the precoding matrix meets a model: U=W 1 ·W 2 , wherein U is an N t ×r matrix, N t represents a total number of ports or a total number of antennas and r represents a number of transmission layers;
the codebook indication information i 1 is used for representing selection information of K matrixes W i 1 1 . . . W i 1 k , where K is a positive integer; i 3 is used for representing a matrix W i 1 l selected from the K matrixes; i 1 , and i 3 jointly indicate W 1 information; i 2 is used for representing W 2 information; the i 1 , i 2 and i 3 jointly determine a precoding code word matrix U.
17. The method as claimed in claim 16 , wherein the first type of codebook index set I at least comprises i 1 and i 3 information; the second type of codebook index set J at least comprises i 2 information; or,
the first type of codebook index set I at least comprises i 1 and i 2 information; the second type of codebook index set J at least comprises i 3 information; or,
the first type of codebook index set I at least comprises i 1 information; the second type of codebook index set J at least comprises i 2 and i 3 information.
18. A device for feeding back Channel State Information (CSI) in a multi-input multi-output system, the device comprising:
a first obtaining module, configured to obtain codebook index information; and
a first sending module, configured to feed back the CSI comprising the codebook index information to an evolved Node B (eNodeB), wherein
the codebook index information comprises: a first type of codebook index set I and a second type of codebook index set J; a combination of the first type of index set I and the second type of index set J is used for indicating a precoding matrix U, and the precoding matrix U is an N t ×r matrix, where N t represents a total number of ports or a total number of antennas and r represents a number of transmission layers; the precoding matrix U is composed of at least Q×r basic vectors having a dimension of N t /Q, where Q≥2, r≥1, and Q and r are both positive integers; the basic vectors are columns extracted from a matrix B composed of M columns of N t /Q-dimensional vectors, where M is a positive integer;
a union of the first type of index set I and the second type of index set J at least comprises codebook indication information i 1 , i 2 and i 3 ;
the codebook indication information i 1 is used for representing selection information of K matrixes W i 1 1 . . . W i 1 k , where K is a positive integer, each column of the K matrixes W i 1 1 . . . W i 1 k is extracted from column vectors comprised in the matrix B; i 3 is used for representing a matrix W i 1 l selected from the K matrixes; i 2 is used for representing information of one or more basic vectors extracted from the matrix W i 1 l and used to construct the precoding matrix U.
19. A device for feeding back Channel State Information (CSI) in a multi-input multi-output system, the device comprising:
an obtaining module, configured to obtain codebook index information; and
a sending module, configured to feed back the CSI comprising the codebook index information to an evolved Node B (eNodeB), wherein
the codebook index information comprises: a first type of codebook index set I and a second type of codebook index set J; a combination of the first type of index set I and the second type of index set J is used for indicating a precoding matrix U; a union of the first type of index set I and the second type of index set J comprises codebook indication information i 1 , i 2 and i 3 ; the precoding matrix meets a model: U=W 1 ·W 2 , wherein U is an N t ×r matrix, N t represents a total number of ports or a total number of antennas and r represents a number of transmission layers;
the codebook indication information i 1 is used for representing selection information of K matrixes W i 1 1 . . . W i 1 k , where K is a positive integer; i 3 is used for representing a matrix W i 1 l selected from the K matrixes; i 1 and i 3 jointly indicate W 1 information; i 2 is used for representing W 2 information; i 1 , i 2 and i 3 jointly determine a precoding code word matrix U.
20. A non-transitory computer readable storage medium, which stores a computer executable instruction, wherein the computer executable instruction is used to implement the method as claimed in claim 1 .