Method and apparatus for higher rank CSI reporting in advanced wireless communication systems
The present disclosure relates to a communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. A method of operating a user equipment (UE) for CSI feedback is provided. The method comprises receiving configuration information for the CSI feedback from a base station (BS) and identifying a number of antenna ports for the CSI feedback. The method comprises, if the number of antenna ports is <16, identifying a first codebook for the CSI feedback corresponding to a rank value of 3 or 4, and, if otherwise, identifying a second codebook for the CSI feedback corresponding to the rank value of 3 or 4. The method comprises generating the CSI feedback using the identified codebook and transmitting the generated CSI feedback to the BS. The first codebook has a structure that partitions the antenna ports into two equal partitions. The second codebook has a structure that partitions the antenna ports into four equal partitions by partitioning each partition into two equal sub-partitions.
1. A user equipment (UE) for channel state information (CSI) feedback, the UE comprising:
a transceiver; and
a processor operably connected to the transceiver, the processor configured to:
receive, from a base station (BS) via the transceiver, configuration information for the CSI feedback,
identify that a number of antenna ports configured by the configuration information for the CSI feedback is equal to or larger than 16,
in response to identifying that the number of antenna ports for the CSI feedback is equal to or larger than 16, identify a codebook for the CSI feedback corresponding to a rank value of 3 or 4,
generate the CSI feedback based on the identified codebook, and
transmit, to the BS, the generated CSI feedback,
wherein the codebook is based on a common beam {tilde over (v)} i 1,1 ,i 1,2 for the codebook, and a first co-phasing parameter φ n and a second co-phasing parameter θ p applied to the common beam.
2. The UE of claim 1 , wherein:
the CSI feedback includes a pre-coding matrix indicator (PMI) that for the rank value of 3 or 4 includes PMI indices i 1,1 , i 1,2 , and i 1,3 , and
for the codebook, the PMI indices i 1,1 and i 1,2 indicate the common beam {tilde over (v)} i 1,1 ,i 1,2 and the PMI index i 1,3 indicates the second co-phasing parameter θ p .
3. The UE of claim 2 , wherein, for the CSI feedback corresponding to the rank value of 3:
the codebook is determined based on a following pre-coding matrix:
W
l
,
m
,
p
,
n
(
3
)
=
1
3
P
CSI
-
RS
[
v
~
l
,
m
v
~
l
,
m
v
~
l
,
m
θ
p
v
~
l
,
m
θ
p
v
~
l
,
m
-
θ
p
v
~
l
,
m
φ
n
v
~
l
,
m
-
φ
n
v
~
l
,
m
φ
n
v
~
l
,
m
φ
n
θ
p
v
~
l
,
m
-
φ
n
θ
p
v
~
l
,
m
-
φ
n
θ
p
v
~
l
,
m
]
where l=i 1,1 , m=i 1,2 , l′=i 1,1 +k 1 , m′=i 1,2 +k 2 , p=i 1,3 , n=i 2 , P CSI-RS is the number of antenna ports, and
φ
n
=
e
j
π
n
/
2
θ
p
=
e
j
π
p
/
4
u
m
=
{
[
1
e
j
2
π
m
O
2
N
2
…
e
j
2
π
m
(
N
2
-
1
)
O
2
N
2
]
N
2
>
1
1
N
2
=
1
.
v
l
,
m
=
[
u
m
e
j
2
π
l
O
1
N
1
u
m
…
e
j
2
π
l
(
N
1
-
1
)
O
1
N
1
u
m
]
T
v
~
l
,
m
=
[
u
m
e
j
4
π
l
O
1
N
1
u
m
…
e
j
4
π
l
(
N
1
/
2
-
1
)
O
1
N
1
u
m
]
T
4. The UE of claim 2 , wherein, for the CSI feedback corresponding to the rank value of 4:
the codebook is determined based on a following pre-coding matrix:
W
l
,
m
,
p
,
n
(
4
)
=
1
4
P
CSI
-
RS
[
v
~
l
,
m
v
~
l
,
m
v
~
l
,
m
v
~
l
,
m
θ
p
v
~
l
,
m
θ
p
v
~
l
,
m
-
θ
p
v
~
l
,
m
-
θ
p
v
~
l
,
m
φ
n
v
~
l
,
m
-
φ
n
v
~
l
,
m
φ
n
v
~
l
,
m
-
φ
n
v
~
l
,
m
φ
n
θ
p
v
~
l
,
m
-
φ
n
θ
p
v
~
l
,
m
-
φ
n
θ
p
v
~
l
,
m
φ
n
θ
p
v
~
l
,
m
]
,
where l=i 1,1 , m=i 1,2 , l′=i 1,1 +k 1 , m′=i 1,2 +k 2 , p=i 1,3 , n=i 2 , P CSI-RS is the number of antenna ports, and
φ
n
=
e
j
π
n
/
2
θ
p
=
e
j
π
p
/
4
u
m
=
{
[
1
e
j
2
π
m
O
2
N
2
…
e
j
2
π
m
(
N
2
-
1
)
O
2
N
2
]
N
2
>
1
1
N
2
=
1
.
v
l
,
m
=
[
u
m
e
j
2
π
l
O
1
N
1
u
m
…
e
j
2
π
l
(
N
1
-
1
)
O
1
N
1
u
m
]
T
v
~
l
,
m
=
[
u
m
e
j
4
π
l
O
1
N
1
u
m
…
e
j
4
π
l
(
N
1
/
2
-
1
)
O
1
N
1
u
m
]
T
5. The UE of claim 2 , wherein the second co-phasing parameter θ p =e jπp/4 , where i 1,3 =p=0,1,2,3.
6. The UE of claim 2 , wherein the PMI that for the rank value of 3 or 4 further includes a PMI index i 2 that indicates the first co-phasing parameter φ n , where φ n =e jπn/2 , and i 2 =n=0,1.
7. A base station (BS) for receiving channel state information (CSI) feedback, the BS comprising:
a transceiver;
a processor operably connected to the transceiver, the processor configured to:
transmit, to a user equipment (UE) via the transceiver, configuration information for the CSI feedback, and
receive, from the UE, the CSI feedback generated by the UE,
wherein a number of antenna ports configured by the configuration information for the CSI feedback is equal to or larger than 16 and the CSI feedback has a rank corresponding to a rank value of 3 or 4 that is generated based on a codebook, and
wherein the codebook is based on a common beam {tilde over (v)} i 1,1 ,i 1,2 for the codebook, and a first co-phasing parameter φ n and a second co-phasing parameter θ p applied to the common beam.
8. The BS of claim 7 , wherein:
the CSI feedback includes a pre-coding matrix indicator (PMI) that for the rank value of 3 or 4 includes PMI indices i 1,1 , i 1,2 , and i 1,3 , and
for the codebook, the PMI indices i 1,1 and i 1,2 indicate the common beam {tilde over (v)} i 1,1 ,i 1,2 , and the PMI index i 1,3 indicates the second co-phasing parameter θ p .
9. The BS of claim 8 , wherein, for the CSI feedback corresponding to the rank value of 3:
the codebook is determined based on a following pre-coding matrix:
W
l
,
m
,
p
,
n
(
3
)
=
1
3
P
CSI
-
RS
[
v
~
l
,
m
v
~
l
,
m
v
~
l
,
m
θ
p
v
~
l
,
m
θ
p
v
~
l
,
m
-
θ
p
v
~
l
,
m
φ
n
v
~
l
,
m
-
φ
n
v
~
l
,
m
φ
n
v
~
l
,
m
φ
n
θ
p
v
~
l
,
m
-
φ
n
θ
p
v
~
l
,
m
-
φ
n
θ
p
v
~
l
,
m
]
,
where l=i 1,1 , m=i 1,2 , l′=i 1,1 +k 1 , m′=i 1,2 +k 2 , p=i 1,3 , n=i 2 , P CSI-RS is the number of antenna ports, and
φ
n
=
e
j
π
n
/
2
θ
p
=
e
j
π
p
/
4
u
m
=
{
[
1
e
j
2
π
m
O
2
N
2
…
e
j
2
π
m
(
N
2
-
1
)
O
2
N
2
]
N
2
>
1
1
N
2
=
1
.
v
l
,
m
=
[
u
m
e
j
2
π
l
O
1
N
1
u
m
…
e
j
2
π
l
(
N
1
-
1
)
O
1
N
1
u
m
]
T
v
~
l
,
m
=
[
u
m
e
j
4
π
l
O
1
N
1
u
m
…
e
j
4
π
l
(
N
1
/
2
-
1
)
O
1
N
1
u
m
]
T
10. The BS of claim 8 , wherein, for the CSI feedback corresponding to the rank value of 4:
the codebook is determined based on a following pre-coding matrix:
W
l
,
m
,
p
,
n
(
4
)
=
1
4
P
CSI
-
RS
[
v
~
l
,
m
v
~
l
,
m
v
~
l
,
m
v
~
l
,
m
θ
p
v
~
l
,
m
θ
p
v
~
l
,
m
-
θ
p
v
~
l
,
m
-
θ
p
v
~
l
,
m
φ
n
v
~
l
,
m
-
φ
n
v
~
l
,
m
φ
n
v
~
l
,
m
-
φ
n
v
~
l
,
m
φ
n
θ
p
v
~
l
,
m
-
φ
n
θ
p
v
~
l
,
m
-
φ
n
θ
p
v
~
l
,
m
φ
n
θ
p
v
~
l
,
m
]
,
where l=i 1,1 , m=i 1,2 , l′=i 1,1 +k 1 , m′=i 1,2 +k 2 p=i 1,3 , n=i 2 , P CSI-RS is the number of antenna ports, and
φ
n
=
e
j
π
n
/
2
θ
p
=
e
j
π
p
/
4
u
m
=
{
[
1
e
j
2
π
m
O
2
N
2
…
e
j
2
π
m
(
N
2
-
1
)
O
2
N
2
]
N
2
>
1
1
N
2
=
1
.
v
l
,
m
=
[
u
m
e
j
2
π
l
O
1
N
1
u
m
…
e
j
2
π
l
(
N
1
-
1
)
O
1
N
1
u
m
]
T
v
~
l
,
m
=
[
u
m
e
j
4
π
l
O
1
N
1
u
m
…
e
j
4
π
l
(
N
1
/
2
-
1
)
O
1
N
1
u
m
]
T
11. The BS of claim 8 , wherein the second co-phasing parameter θ p =e jπp/4 , where i 1,3 =p=0,1,2,3.
12. The BS of claim 8 , wherein the PMI that for the rank value of 3 or 4 further includes a PMI index i 2 that indicates the first co-phasing parameter φ n , where φ n =e jπn/2 , and i 2 =n=0,1.
13. A method performed by a user equipment (UE) for channel state information (CSI) feedback, the method comprising:
receiving, from a base station (BS), configuration information for the CSI feedback;
identifying that a number of antenna ports configured by the configuration information for the CSI feedback is equal to or larger than 16;
in response to identifying that the number of antenna ports for the CSI feedback is equal to or larger than 16, identifying a codebook for the CSI feedback corresponding to a rank value of 3 or 4;
generating the CSI feedback using the identified codebook; and
transmitting the generated CSI feedback to the BS,
wherein the codebook is based on a common beam {tilde over (v)} i 1,1 ,i 1,2 for the codebook, and a first co-phasing parameter φ n and a second co-phasing parameter θ p applied to the common beam.
14. The method of claim 13 , wherein:
the CSI feedback includes a pre-coding matrix indicator (PMI) that for the rank value of 3 or 4 includes PMI indices i 1,1 , i 1,2 , and i 1,3 , and
for the codebook, the PMI indices i 1,1 and i 1,2 indicate the common beam {tilde over (v)} i 1,1 ,i 1,2 , and the PMI index i 1,3 indicates the second co-phasing parameter θ p .
15. The method of claim 14 , wherein, for the CSI feedback corresponding to the rank value of 3:
the codebook is determined based on a following pre-coding matrix:
W
l
,
m
,
p
,
n
(
3
)
=
1
3
P
CSI
-
RS
[
v
~
l
,
m
v
~
l
,
m
v
~
l
,
m
θ
p
v
~
l
,
m
θ
p
v
~
l
,
m
-
θ
p
v
~
l
,
m
φ
n
v
~
l
,
m
-
φ
n
v
~
l
,
m
φ
n
v
~
l
,
m
φ
n
θ
p
v
~
l
,
m
-
φ
n
θ
p
v
~
l
,
m
-
φ
n
θ
p
v
~
l
,
m
]
,
where l=i 1,1 , m=i 1,2 , l′=i 1,1 +k 1 , m′=i 1,2 +k 2 , p=i 1,3 , n=i 2 , P CSI-RS is the number of antenna ports, and
φ
n
=
e
j
π
n
/
2
θ
p
=
e
j
π
p
/
4
u
m
=
{
[
1
e
j
2
π
m
O
2
N
2
…
e
j
2
π
m
(
N
2
-
1
)
O
2
N
2
]
N
2
>
1
1
N
2
=
1
.
v
l
,
m
=
[
u
m
e
j
2
π
l
O
1
N
1
u
m
…
e
j
2
π
l
(
N
1
-
1
)
O
1
N
1
u
m
]
T
v
~
l
,
m
=
[
u
m
e
j
4
π
l
O
1
N
1
u
m
…
e
j
4
π
l
(
N
1
/
2
-
1
)
O
1
N
1
u
m
]
T
16. The method of claim 14 , wherein, for the CSI feedback corresponding to the rank value of 4:
the codebook is determined based on a following pre-coding matrix:
W
l
,
m
,
p
,
n
(
4
)
=
1
4
P
CSI
-
RS
[
v
~
l
,
m
v
~
l
,
m
v
~
l
,
m
v
~
l
,
m
θ
p
v
~
l
,
m
θ
p
v
~
l
,
m
-
θ
p
v
~
l
,
m
-
θ
p
v
~
l
,
m
φ
n
v
~
l
,
m
-
φ
n
v
~
l
,
m
φ
n
v
~
l
,
m
-
φ
n
v
~
l
,
m
φ
n
θ
p
v
~
l
,
m
-
φ
n
θ
p
v
~
l
,
m
-
φ
n
θ
p
v
~
l
,
m
φ
n
θ
p
v
~
l
,
m
]
,
where l=i 1,1 , m=i 1,2 , l′=i 1,1 +k 1 , m′=i 1,2 +k 2 , p=i 1,3 , n=i 2 , P CSI-RS is the number of antenna ports, and
φ
n
=
e
j
π
n
/
2
θ
p
=
e
j
π
p
/
4
u
m
=
{
[
1
e
j
2
π
m
O
2
N
2
…
e
j
2
π
m
(
N
2
-
1
)
O
2
N
2
]
N
2
>
1
1
N
2
=
1
.
v
l
,
m
=
[
u
m
e
j
2
π
l
O
1
N
1
u
m
…
e
j
2
π
l
(
N
1
-
1
)
O
1
N
1
u
m
]
T
v
~
l
,
m
=
[
u
m
e
j
4
π
l
O
1
N
1
u
m
…
e
j
4
π
l
(
N
1
/
2
-
1
)
O
1
N
1
u
m
]
T
17. The method of claim 14 , wherein the second co-phasing parameter θ p =e jπp/4 , where i 1,3 =p=0,1,2,3.
18. The method of claim 14 , wherein the PMI that for the rank value of 3 or 4 further includes a PMI index i 2 that indicates the first co-phasing parameter φ n , where φ n =e jπn/2 , and i 2 =n=0,1.
19. A method performed by a base station (BS) for receiving channel state information (CSI) feedback, the method comprising:
transmitting, to a user equipment (UE), configuration information for the CSI feedback; and
receiving, from the UE, the CSI feedback generated by the UE,
wherein a number of antenna ports configured by the configuration information for the CSI feedback is equal to or larger than 16 and the CSI feedback has a rank corresponding to a rank value of 3 or 4 that is generated based on a codebook, and
wherein the codebook is based on a common beam {tilde over (v)} i 1,1 ,i 1,2 for the codebook, and a first co-phasing parameter φ n , and a second co-phasing parameter θ p applied to the common beam.
20. The method of claim 19 , wherein:
the CSI feedback includes a pre-coding matrix indicator (PMI) that for the rank value of 3 or 4 includes PMI indices i 1,1 , i 1,2 , and i 1,3 , and
for the codebook, the PMI indices i 1,1 and i 1,2 indicate the beam {tilde over (v)} i 1,1 ,i 1,2 , and the PMI index i 1,3 indicates the second co-phasing parameter θ p .
21. The method of claim 20 , wherein the first co-phasing parameter θ p =e jπp/4 , where i 1,3 =p=0,1,2,3.
22. The method of claim 20 , wherein the PMI that for the rank value of 3 or 4 further includes a PMI index i 2 that indicates the co-phasing parameter φ n , where φ n =e jπn/2 , and i 2 =n=0,1.
23. The method of claim 20 , wherein, for the CSI feedback corresponding to the rank value of 3:
the codebook is determined based on a following pre-coding matrix:
W
l
,
m
,
p
,
n
(
3
)
=
1
3
P
CSI
-
RS
[
v
~
l
,
m
v
~
l
,
m
v
~
l
,
m
θ
p
v
~
l
,
m
θ
p
v
~
l
,
m
-
θ
p
v
~
l
,
m
φ
n
v
~
l
,
m
-
φ
n
v
~
l
,
m
φ
n
v
~
l
,
m
φ
n
θ
p
v
~
l
,
m
-
φ
n
θ
p
v
~
l
,
m
-
φ
n
θ
p
v
~
l
,
m
]
,
where l=i 1,1 , m=i 1,2 , l′=i 1,1 +k 1 , m′=i 1,2 +k 2 , p=i 1,3 , n=i 2 , P CSI-RS is the number of antenna ports, and
φ
n
=
e
j
π
n
/
2
θ
p
=
e
j
π
p
/
4
u
m
=
{
[
1
e
j
2
π
m
O
2
N
2
…
e
j
2
π
m
(
N
2
-
1
)
O
2
N
2
]
N
2
>
1
1
N
2
=
1
v
l
,
m
=
[
u
m
e
j
2
π
l
O
1
N
1
u
m
…
e
j
2
π
l
(
N
1
-
1
)
O
1
N
1
u
m
]
T
v
~
l
,
m
=
[
u
m
e
j
4
π
l
O
1
N
1
u
m
…
e
j
4
π
l
(
N
1
/
2
-
1
)
O
1
N
1
u
m
]
T
.
24. The method of claim 20 , wherein, for the CSI feedback corresponding to the rank value of 4:
the codebook is determined based on a following pre-coding matrix:
W
l
,
m
,
p
,
n
(
4
)
=
1
4
P
CSI
-
RS
[
v
~
l
,
m
v
~
l
,
m
v
~
l
,
m
v
~
l
,
m
θ
p
v
~
l
,
m
θ
p
v
~
l
,
m
-
θ
p
v
~
l
,
m
-
θ
p
v
~
l
,
m
φ
n
v
~
l
,
m
-
φ
n
v
~
l
,
m
φ
n
v
~
l
,
m
-
φ
n
v
~
l
,
m
φ
n
θ
p
v
~
l
,
m
-
φ
n
θ
p
v
~
l
,
m
-
φ
n
θ
p
v
~
l
,
m
φ
n
θ
p
v
~
l
,
m
]
,
where l=i 1,1 , m=i 1,2 , l′=i 1,1 +k 1 , =i 1,2 +k 2 , p=i 1,3 , n=i 2 , P CSI-RS is the number of antenna ports, and
φ
n
=
e
j
π
n
/
2
θ
p
=
e
j
π
p
/
4
u
m
=
{
[
1
e
j
2
π
m
O
2
N
2
…
e
j
2
π
m
(
N
2
-
1
)
O
2
N
2
]
N
2
>
1
1
N
2
=
1
v
l
,
m
=
[
u
m
e
j
2
π
l
O
1
N
1
u
m
…
e
j
2
π
l
(
N
1
-
1
)
O
1
N
1
u
m
]
T
v
~
l
,
m
=
[
u
m
e
j
4
π
l
O
1
N
1
u
m
…
e
j
4
π
l
(
N
1
/
2
-
1
)
O
1
N
1
u
m
]
T
.