CSI-RS measurement feedback method and device
A CSI-RS measurement feedback method and device are provided to optimize analog and digital precoding. A network device sends S CSI-RSs to a terminal device. Each CSI-RS corresponds to one antenna port number. The terminal device sends M antenna port numbers that correspond to M CSI-RSs and sends a PMI that corresponds to a channel matrix H or the quantization result of a channel matrix H to the network device. The terminal device selects the M antenna port numbers that correspond to the M CSI-RSs from the S antenna port numbers that correspond to the S CSI-RSs, and feeds back the M antenna port numbers to the network device.
1. A channel state information reference signal (CSI-RS) measurement feedback method, wherein the method comprises:
receiving S channel state information reference signals (CSI-RSs) from a network device, wherein each CSI-RS corresponds to one antenna port number, and S is a positive integer; and
sending M antenna port numbers that correspond to M CSI-RSs to the network device, and sending a precoding matrix indicator (PMI) that corresponds to a quantization result of a channel matrix H to the network device, wherein the channel matrix H corresponds to the M CSI-RSs, any row in the channel matrix H comprises M elements, S>M or S=M, and M is a positive integer;
wherein the quantization result of the channel matrix H comprises quantized values of modulus values and quantized values of phases that respectively correspond to M elements that are comprised in a quantization matrix that corresponds to the channel matrix H.
2. The method according to claim 1 , wherein the M CSI-RSs are M CSI-RSs whose signal receiving strengths are selected in descending order from signal receiving strengths that respectively correspond to the S CSI-RSs.
3. The method according to claim 2 , wherein the sending M antenna port numbers that correspond to M CSI-RSs to the network device comprises:
sending the M antenna port numbers on a physical uplink shared channel (PUSCH) or a physical uplink control channel (PUCCH); or
sending PMIs of first matrices that correspond to the M antenna port numbers in a first codebook, wherein the first codebook comprises a plurality of predefined first matrices, each first matrix corresponds to one PMI, each first matrix is an S×1 matrix, S elements in each first matrix correspond one-to-one to S antenna port numbers that correspond to the S CSI-RSs, values of elements that respectively correspond to the M antenna port numbers in each of the first matrices that correspond to the M antenna port numbers are 1, and values of remaining SM elements in each of the first matrices are 0.
4. The method according to claim 1 , wherein the quantization result of the channel matrix H comprises M groups of values, and an i th group of values comprises a value of an i th k 1 and a value of an i th k 2 that respectively correspond to |h i1 | and ϕ i1 , wherein
H
′
=
[
h
11
,
…
,
h
i
1
,
…
,
h
M
1
]
T
=
[
h
11
e
j
ϕ
1
,
1
,
…
,
h
i
1
e
j
ϕ
i
,
1
,
…
,
h
M
1
e
j
ϕ
M
,
1
]
T
,
wherein
h
i
1
=
a
+
(
b
-
a
)
(
1
2
B
amp
+
1
+
1
2
B
amp
k
1
)
,
k
1
=
0
,
1
,
…
,
2
B
amp
-
1
ϕ
i
1
=
2
π
(
1
2
B
ϕ
+
1
+
1
2
B
ϕ
+
1
k
2
)
,
k
2
=
0
,
1
,
…
,
2
B
ϕ
-
1
,
a indicates a minimum quantization value, b indicates a maximum quantization value, B amp indicates a quantity of quantization bits of |h i1 |, B ϕ indicates a quantity of quantization bits of ϕ i1 , i is a positive integer less than or equal to M, and the M groups of values all meet a throughput maximization principle or an estimated signal to interference plus noise ratio maximization principle.
5. The method according to claim 1 , wherein the quantization result of the channel matrix H comprises a quantized value |H| of a modulus value of a quantization matrix H′, quantized values of phases (ϕ 1,1 , . . . , ϕ i,1 , . . . , ϕ M,1 ) that respectively correspond to the M elements, and quantized values of transformation phases (ψ M,1 , L, ψ i,1 , L, ψ 2,1 ) that respectively correspond to an M th element to the second element, so that the network device recovers H 1 according to the following formula:
H 1 =|H|DG M1 T (ψ M,1 ) L G i1 T (ψ i,1 ) L G 21 T (ψ 2,1 ) e 1 , wherein
H′=[h 11 , . . . , h i1 , . . . , h M1 ] T =[|h 11 |e jϕ 1,1 , . . . , |h i1 |e jϕ i,1 , . . . , |h M1 |e jϕ M,1 ] T ,
a diagonal matrix D is:
D
=
[
e
j
ϕ
1
,
1
L
0
L
0
0
O
0
L
0
M
0
e
j
ϕ
i
,
1
0
M
M
M
0
O
0
0
0
L
0
e
j
ϕ
M
,
1
]
,
a k th Givens rotation matrix is:
G
i
1
(
ψ
i
,
1
)
=
[
0
0
0
0
0
0
cos
(
ψ
i
,
1
)
0
sin
(
ψ
i
,
1
)
0
0
0
I
i
-
2
0
0
0
-
sin
(
ψ
i
,
1
)
0
cos
(
ψ
i
,
1
)
0
0
0
0
0
0
]
,
i is a positive integer less than or equal to M, the transformation phases (ψ M,1 , L, ψ i,1 , L, ψ 2,1 ) that respectively correspond to the M th element to the second element are obtained based on the channel matrix H and the diagonal matrix D, e 1 =[1, 0, . . . , 0] T , and I i-2 represents an identity matrix of (i−2)×(i−2).
6. The method according to claim 1 , the method further comprises:
receiving, from the network device, data of antenna ports that respectively correspond to the M antenna port numbers, wherein the data is data encoded based on a precoding matrix.
7. An apparatus comprising:
a memory; and
one or more processors coupled to the memory, wherein the one or more processors are configured to:
receive S channel state information reference signals (CSI-RSs) from a network device, wherein each CSI-RS corresponds to one antenna port number, and S is a positive integer; and
send M antenna port numbers that correspond to M CSI-RSs to the network device, and send a precoding matrix indicator (PMI) that corresponds to a quantization result of a channel matrix H to the network device, wherein the channel matrix H corresponds to the M CSI-RSs, any row in the channel matrix H comprises M elements, S>M or S=M, and M is a positive integer;
wherein the quantization result of the channel matrix H comprises quantized values of modulus values and quantized values of phases that respectively correspond to M elements that are comprised in a quantization matrix H′ that corresponds to the channel matrix H.
8. The apparatus according to claim 7 , wherein the M CSI-RSs are M CSI-RSs whose signal receiving strengths are selected in descending order from signal receiving strengths that respectively correspond to the S CSI-RSs.
9. The apparatus according to claim 8 , wherein the one or more processors are configured to:
send the M antenna port numbers on a physical uplink shared channel PUSCH or a physical uplink control channel PUCCH; or
send PMIs of first matrices that correspond to the M antenna port numbers in a first codebook, wherein the first codebook comprises a plurality of predefined first matrices, each first matrix corresponds to one PMI, each first matrix is an S×1 matrix, S elements in each first matrix correspond one-to-one to S antenna port numbers that correspond to the S CSI-RSs, values of elements that respectively correspond to the M antenna port numbers in the first matrices that correspond to the M antenna port numbers are 1, and values of remaining S-M elements are 0.
10. The apparatus according to claim 7 , wherein the quantization result of the channel matrix H comprises M groups of values, and an i th group of values comprises a value of an i th k 1 and a value of an i th k 2 that respectively correspond to |h i1 | and ϕ i1 , wherein
H
′
=
[
h
11
,
…
,
h
i
1
,
…
,
h
M
1
]
T
=
[
h
11
e
j
ϕ
1
,
1
,
…
,
h
i
1
e
j
ϕ
i
,
1
,
…
,
h
M
1
e
j
ϕ
M
,
1
]
T
,
wherein
h
i
1
=
a
+
(
b
-
a
)
(
1
2
B
amp
+
1
+
1
2
B
amp
k
1
)
,
k
1
=
0
,
1
,
…
,
2
B
amp
-
1
ϕ
i
1
=
2
π
(
1
2
B
ϕ
+
1
+
1
2
B
ϕ
+
1
k
2
)
,
k
2
=
0
,
1
,
…
,
2
B
ϕ
-
1
,
a indicates a minimum quantization value, b indicates a maximum quantization value, B amp indicates a quantity of quantization bits of |h i1 |, B ϕ indicates a quantity of quantization bits of ϕ i1 , i is a positive integer less than or equal to M, and the M groups of values all meet a throughput maximization principle or an estimated signal to interference plus noise ratio maximization principle.
11. The apparatus according to claim 7 , wherein the quantization result of the channel matrix H comprises a quantized value |H| of a modulus value of a quantization matrix H′, quantized values of phases (ϕ i,1 , . . . , ϕ i,1 , . . . , ϕ M,1 ) that respectively correspond to the M elements, and quantized values of transformation phases (ψ M,1 , L, ψ i,1 , L, ψ 2,1 ) that respectively correspond to an M th element to the second element, so that the network device recovers H 1 according to the following formula:
H 1 =|H|DG M1 T (ψ M,1 ) L G i1 T (ψ i,1 ) L G 21 T (ψ 2,1 ) e 1 , wherein
H′=[h 11 , . . . , h i1 , . . . , h M1 ] T =[|h 11 |e jϕ i,i , . . . , |h i1 |e jϕ i,1 , . . . , |h M1 |e jϕ M,1 ] T ,
a diagonal matrix D is:
D
=
[
e
j
ϕ
1
,
1
L
0
L
0
0
O
0
L
0
M
0
e
j
ϕ
i
,
1
0
M
M
M
0
O
0
0
0
L
0
e
j
ϕ
M
,
1
]
,
a k th Givens rotation matrix is:
G
i
1
(
ψ
i
,
1
)
=
[
0
0
0
0
0
0
cos
(
ψ
i
,
1
)
0
sin
(
ψ
i
,
1
)
0
0
0
I
i
-
2
0
0
0
-
sin
(
ψ
i
,
1
)
0
cos
(
ψ
i
,
1
)
0
0
0
0
0
0
]
,
i is a positive integer less than or equal to M, the transformation phases (ψ M,1 , L, ψ i,1 , L, ψ 2,1 ) that respectively correspond to the M th element to the second element are obtained based on the channel matrix H and the diagonal matrix D, e 1 =[1, 0, . . . , 0] T , and I i-2 represents an identity matrix of (i−2)×(i−2).
12. The apparatus according to claim 7 , wherein the one or more processors are further configured to:
receive from the network device, data of antenna ports that respectively correspond to the M antenna port numbers, wherein the data is data encoded based on a precoding matrix.
13. An apparatus comprising:
a memory; and
one or more processors coupled to the memory, wherein the one or more processors are configured to:
send S CSI-RSs, wherein each CSI-RS corresponds to one antenna port number, and S is a positive integer; and
receive M antenna port numbers that correspond to M CSI-RSs from a terminal device, and a PMI that corresponds to a quantization result of a channel matrix H, wherein the channel matrix H corresponds to the M CSI-RSs, the channel matrix H comprises M elements, S≥M, and M is a positive integer;
wherein the quantization result of the channel matrix H comprises quantized values of modulus values and quantized values of phases that respectively correspond to M elements that are comprised in a quantization matrix H′ that corresponds to the channel matrix H.
14. The apparatus according to claim 13 , wherein the M CSI-RSs are M CSI-RSs whose signal receiving strengths are selected in descending order from signal receiving strengths that respectively correspond to the S CSI-RSs.
15. The apparatus according to claim 14 , wherein the one or more processors are configured to:
receive the M antenna port numbers that correspond to the M CSI-RSs and that are sent by the terminal device on a physical uplink shared channel (PUSCH) or a physical uplink control channel (PUCCH); or
receive PMIs that are sent by the terminal device and that are of first matrices that correspond to the M antenna port numbers in a first codebook, wherein the first codebook comprises a plurality of predefined first matrices, each first matrix corresponds to one PMI, each first matrix is an S×1 matrix, S elements in each first matrix correspond one-to-one to S antenna port numbers that correspond to the S CSI-RSs, values of elements that respectively correspond to the M antenna port numbers in the first matrices that correspond to the M antenna port numbers are 1, and values of remaining S-M elements are 0.
16. The apparatus according to claim 13 , wherein the quantization result of the channel matrix H comprises M groups of values, and an i th group of values comprises a value of an i th k 1 and a value of an i th k 2 that respectively correspond to |h i1 | and ϕ i1 , wherein
H
′
=
[
h
11
,
…
,
h
i
1
,
…
,
h
M
1
]
T
=
[
h
11
e
j
ϕ
1
,
1
,
…
,
h
i
1
e
j
ϕ
i
,
1
,
…
,
h
M
1
e
j
ϕ
M
,
1
]
T
,
wherein
h
i
1
=
a
+
(
b
-
a
)
(
1
2
B
amp
+
1
+
1
2
B
amp
k
1
)
,
k
1
=
0
,
1
,
…
,
2
B
amp
-
1
ϕ
i
1
=
2
π
(
1
2
B
ϕ
+
1
+
1
2
B
ϕ
+
1
k
2
)
,
k
2
=
0
,
1
,
…
,
2
B
ϕ
-
1
,
a indicates a minimum quantization value, b indicates a maximum quantization value, B amp indicates a quantity of quantization bits of |h i1 |, B ϕ indicates a quantity of quantization bits of ϕ i1 , i is a positive integer less than or equal to M, and the M groups of values all meet a throughput maximization principle or an estimated signal to interference plus noise ratio maximization principle.
17. The apparatus according to claim 13 , wherein the quantization result of the channel matrix H comprises a quantized value |H| of a modulus value of a quantization matrix H′, quantized values of phases (ϕ 1,1 , . . . , ϕ i,1 , . . . , ϕ M,1 ) that respectively correspond to the M elements, and quantized values of transformation phases (ψ M,1 , L, ψ i,1 , L, ψ 2,1 ) that respectively correspond to an M th element to the second element, so that the network device recovers H 1 according to the following formula:
H 1 =|H|DG M1 T (ψ M,1 ) L G i1 T (ψ i,1 ) L G 21 T (ψ 2,1 ) e 1 , wherein
H′=[h 11 , . . . , h i1 , . . . , h M1 ] T =[|h 11 |e jϕ i,i , . . . , |h i1 |e jϕ i,1 , . . . , |h M1 |e jϕ M,1 ] T ,
a diagonal matrix D is:
D
=
[
e
j
ϕ
1
,
1
L
0
L
0
0
O
0
L
0
M
0
e
j
ϕ
i
,
1
0
M
M
M
0
O
0
0
0
L
0
e
j
ϕ
M
,
1
]
,
a k th Givens rotation matrix is:
G
i
1
(
ψ
i
,
1
)
=
[
0
0
0
0
0
0
cos
(
ψ
i
,
1
)
0
sin
(
ψ
i
,
1
)
0
0
0
I
i
-
2
0
0
0
-
sin
(
ψ
i
,
1
)
0
cos
(
ψ
i
,
1
)
0
0
0
0
0
0
]
,
i is a positive integer less than or equal to M, the transformation phases (ψ M,1 , L, ψ i,1 , L, ψ 2,1 ) that respectively correspond to the M th element to the second element are obtained based on the channel matrix H and the diagonal matrix D, e 1 =[1, 0, . . . , 0] T , and I i-2 represents an identity matrix of (i−2)×(i−2).