Method and apparatus for CSI parameter configuration in wireless communication systems

1. A user equipment (UE) for channel state information (CSI) feedback in a wireless communication system, the UE comprising:

a transceiver configured to receive CSI feedback configuration information including codebook parameters configured jointly via a single radio resource control (RRC) parameter, the codebook parameters comprising L, p, ν 0 , and β, wherein the parameter L determines a number of spatial domain (SD) basis vectors, the parameter β determines a maximum number of coefficients, and the parameters p and ν 0 determine a number (M ν ) of frequency domain (FD) basis vectors, wherein the parameter p is for a first rank set and the parameter ν 0 is for a second rank set; and

a processor operably connected to the transceiver, the processor configured to generate the CSI feedback based on the CSI feedback configuration information, wherein the CSI feedback is generated for a rank value ν from one of the first and second rank sets;

wherein the transceiver is further configured to transmit the CSI feedback over an uplink channel.

2. The UE of claim 1 , wherein a mapping of the codebook parameters configured jointly via the single RRC parameter is determined based on a table given by:

Codebook parameters' values

RRC parameter

p (first

v 0 (second

value

L

rank set)

rank set)

β

x0

2

¼

⅛

¼

x1

2

¼

⅛

½

x2

4

¼

⅛

¼

x3

4

¼

⅛

½

x4

4

¼

¼

¾

x5

4

½

¼

½

x6

6

¼

—

½

x7

6

¼

—

¾

wherein the UE is configured with a value of the single RRC parameter that is configured from a set of values {x0, x1, . . . , x7}.

3. The UE of claim 2 , wherein the UE is not expected to be configured with a value of the single RRC parameter being x6 or x7 indicating that the parameter L=6, when:

the UE is configured with less than 32 channel state information reference signal (CSI-RS) antenna ports,

the UE is allowed to report the rank value ν>2, or

the UE is configured with R=2 indicating that the UE is allowed to report up to 2 precoding matrices in each subband configured for the CSI feedback.

4. The UE of claim 1 , wherein the CSI feedback includes a set of M ν FD basis vectors, where M ν is determined based on the parameter p if the rank value ν belongs to the first rank set and based on the parameter ν 0 if the rank value ν belongs to the second rank set.

5. The UE of claim 1 , wherein the first rank set comprises rank values {1, 2} and the second rank set comprises rank values {3, 4}.

6. The UE of claim 1 , wherein:

M

v

=

⌈

q

×

N

3

R

⌉

where:

q=p for the first rank set and q=ν 0 for the second rank set,

┌ ┐ is a ceiling function,

N 3 is a total number of FD units, and

R is a maximum number of FD units in each subband configured for the CSI feedback.

7. The UE of claim 6 , wherein the CSI feedback includes a precoding matrix indicator (PMI) indicating a coefficient matrix C l , a SD basis matrix A l , and a FD basis matrix B l for each layer l=1, . . . , ν, and

wherein:

a precoding matrix for each FD unit of the total number (N 3 ) of FD units is determined by columns of

W

=

1

v

[

W

1

⁢

W

2

…

W

v

⁢

]

,

⁢

where

⁢

⁢

W

l

=

[

A

l

0

0

A

l

]

⁢

C

l

⁢

B

l

H

=

[

∑

k

=

0

M

-

1

⁢

∑

i

=

0

L

-

1

⁢

c

l

,

i

,

k

⁡

(

a

l

,

i

⁢

b

l

,

k

H

)

∑

k

=

0

M

-

1

⁢

∑

i

=

0

L

-

1

⁢

c

l

,

i

+

L

,

k

⁡

(

a

l

,

i

⁢

b

l

,

k

H

)

]

,

A l =[a l,0 a l,1 . . . a l,L−1 ] comprises L basis vectors for SD antenna ports, a l,i is a N 1 N 2 ×1 column vector, where N 1 and N 2 are number of antenna ports, respectively, with a same antenna polarization in a first and a second dimensions of a two-dimensional dual-polarized channel state information-reference signal (CSI-RS) antenna ports at a BS;

B l =[b l,0 b l,1 b 1,M ν −1 ] comprises M ν basis vectors for FD units, b l,k is a N 3 ×1 column vector;

C 1 is a 2L×M ν matrix comprising complex coefficients c l,i,k ; and

the total number (N 3 ) of the FD units is determined based on the value of R and a number of subbands configured for the CSI feedback.

8. A base station (BS) in a wireless communication system, the BS comprising:

a processor configured to generate CSI feedback configuration information; and

a transceiver operably connected to the processor, the transceiver configured to:

transmit the CSI feedback configuration information including codebook parameters configured jointly via a single radio resource control (RRC) parameter, the codebook parameters comprising L, p, ν 0 , and β, wherein the parameter L determines a number of spatial domain (SD) basis vectors, the parameter β determines a maximum number of coefficients, and the parameters p and ν 0 determine a number (M ν ) of frequency domain (FD) basis vectors, wherein the parameter p is for a first rank set and the parameter ν 0 is for a second rank set, and

receive, over an uplink channel, a CSI feedback generated for a rank value ν from one of the first and second rank sets.

9. The BS of claim 8 , wherein a mapping of the codebook parameters configured jointly via the single RRC parameter is determined based on a table given by:

Codebook parameters' values

RRC parameter

p (first

v 0 (second

value

L

rank set)

rank set)

β

x0

2

¼

⅛

¼

x1

2

¼

⅛

½

x2

4

¼

⅛

¼

x3

4

¼

⅛

½

x4

4

¼

¼

¾

x5

4

½

¼

½

x6

6

¼

—

½

x7

6

¼

—

¾

wherein the UE is configured with a value of the single RRC parameter that is configured from a set of values {x0, x1, . . . , x7}.

10. The BS of claim 9 , wherein the single RRC parameter is not expected to take a value x6 or x7 indicating that the parameter L=6, when the CSI feedback configuration information:

configures less than 32 channel state information reference signal (CSI-RS) antenna ports,

allows the rank value ν>2, or

configures R=2 indicating that up to 2 precoding matrices can be reported in each subband configured for the CSI feedback.

11. The BS of claim 8 , wherein the CSI feedback includes a set of M ν FD basis vectors, where M ν is determined based on the parameter p if the rank value ν belongs to the first rank set and based on the parameter ν 0 if the rank value ν belongs to the second rank set.

12. The BS of claim 8 , wherein the first rank set comprises rank values {1, 2} and the second rank set comprises rank values {3, 4}.

13. The BS of claim 8 , wherein:

M

v

=

⌈

q

×

N

3

R

⌉

where:

q=p for the first rank set and q=ν 0 for the second rank set,

┌ ┐ is a ceiling function,

N 3 is a total number of FD units, and

R is a maximum number of FD units in each subband configured for the CSI feedback.

14. The BS of claim 13 , wherein the CSI feedback includes a precoding matrix indicator (PMI) indicating a coefficient matrix C l , a SD basis matrix A l , and a FD basis matrix B l for each layer 1=1, . . . , ν, and

wherein:

a precoding matrix for each FD unit of the total number (N 3 ) of FD units is determined by columns of

W

=

1

v

[

W

1

⁢

W

2

…

W

v

⁢

]

,

⁢

where

⁢

⁢

W

l

=

[

A

l

0

0

A

l

]

⁢

C

l

⁢

B

l

H

=

[

∑

k

=

0

M

-

1

⁢

∑

i

=

0

L

-

1

⁢

c

l

,

i

,

k

⁡

(

a

l

,

i

⁢

b

l

,

k

H

)

∑

k

=

0

M

-

1

⁢

∑

i

=

0

L

-

1

⁢

c

l

,

i

+

L

,

k

⁡

(

a

l

,

i

⁢

b

l

,

k

H

)

]

,

A l =[a l,0 a l,1 . . . a l,L−1 ] comprises L basis vectors for SD antenna ports, a l,i is a N 1 N 2 ×1 column vector, where N 1 and N 2 are number of antenna ports, respectively, with a same antenna polarization in a first and a second dimensions of a two-dimensional dual-polarized channel state information-reference signal (CSI-RS) antenna ports at the BS;

B l =[b l,0 b l,1 b 1,M ν −1 ] comprises M ν basis vectors for FD units, b l,k is a N 3 ×1 column vector;

C 1 is a 2L×M ν matrix comprising complex coefficients c l,i,k ; and

the total number (N 3 ) of the FD units is determined based on the value of R and a number of subbands configured for the CSI feedback.

15. A method for operating a user equipment (UE) for channel state information (CSI) feedback in a wireless communication system, the method comprising:

receiving CSI feedback configuration information including codebook parameters configured jointly via a single radio resource control (RRC) parameter, the codebook parameters comprising L, p, ν 0 , and β, wherein the parameter L determines a number of spatial domain (SD) basis vectors, the parameter β determines a maximum number of coefficients, and the parameters p and ν 0 determine a number (M ν ) of frequency domain (FD) basis vectors, wherein the parameter p is for a first rank set and the parameter ν 0 is for a second rank set;

generating the CSI feedback based on the CSI feedback configuration information, wherein the CSI feedback is generated for a rank value ν from one of the first and second rank sets; and

transmitting the CSI feedback over an uplink channel.

16. The method of claim 15 , wherein a mapping of the codebook parameters configured jointly via the single RRC parameter is determined based on a table given by:

Codebook parameters' values

RRC parameter

p (first

v 0 (second

value

L

rank set)

rank set)

β

x0

2

¼

⅛

¼

x1

2

¼

⅛

½

x2

4

¼

⅛

¼

x3

4

¼

⅛

½

x4

4

¼

¼

¾

x5

4

½

¼

½

x6

6

¼

—

½

x7

6

¼

—

¾

wherein the UE is configured with a value of the single RRC parameter that is configured from a set of values {x0, x1, . . . , x7}.

17. The method of claim 16 , wherein the UE is not expected to be configured with a value of the single RRC parameter being x6 or x7 indicating that the parameter L=6, when:

the UE is configured with less than 32 channel state information reference signal (CSI-RS) antenna ports,

the UE is allowed to report the rank value ν>2, or

the UE is configured with R=2 indicating that the UE is allowed to report up to 2 precoding matrices in each subband configured for the CSI feedback.

18. The method of claim 1 , wherein the CSI feedback includes a set of M ν FD basis vectors, where M ν is determined based on the parameter p if the rank value ν belongs to the first rank set and based on the parameter ν 0 if the rank value ν belongs to the second rank set.

19. The method of claim 15 , wherein the first rank set comprises rank values {1, 2} and the second rank set comprises rank values {3, 4}.

20. The method of claim 15 , wherein:

M

v

=

⌈

q

×

N

3

R

⌉

where:

q=p for the first rank set and q=ν 0 for the second rank set,

┌ ┐ is a ceiling function,

N 3 is a total number of FD units, and

R is a maximum number of FD units in each subband configured for the CSI feedback.