Method and apparatus for codebook subset restriction for CSI reporting in advanced wireless communication systems
View Patent ↗The method of UE for CSI reporting comprises receiving a higher layer signaling including CB SR information; determining a bitmap sequence B based on the CB SR information, wherein the bitmap sequence B includes a first bitmap sequence B 1 and a second bitmap sequence B 2 ; determining the first bitmap sequence B 1 and the second bitmap sequence B 2 based on the bitmap sequence B; identifying, based on the first bitmap sequence B 1 and the second bitmap sequence B 2 , a restriction on P beam groups out of Q beam groups G(r 1 , r 2 ) for the CSI reporting; generating a CSI report based on the P beam groups with the identified restriction for the CSI reporting and remaining Q minus P beam groups without any restrictions for the CSI reporting; and transmitting the CSI report to the BS. The remaining beam groups are determined as the Q beam groups G(r 1 , r 2 ) minus the P beam groups.
1. A user equipment (UE) for channel state information (CSI) reporting in a wireless communication system, the UE comprising:
a transceiver configured to receive, from a base station (BS), a higher layer signaling including codebook subset restriction (CBSR) information including a bitmap having a portion indicating a restriction on N 1 N 2 beam groups G(r 1 , r 2 ) for an antenna port layout; and
a processor operably connected to the transceiver, the processor configured to
determine a number of beams (L) within each beam group of the N 1 N 2 beam groups G(r 1 , r 2 ), wherein L is O 1 for a one-dimensional antenna port layout (N 2 =1) and L is O 1 O 2 for a two-dimensional antenna port layout (N 2 >1),
identify, based on the CBSR information, the restriction on N 1 N 2 beam groups G(r 1 , r 2 ), and
determine a CSI report based on the identified restriction on the N 1 N 2 beam groups G(r 1 , r 2 ),
wherein the transceiver is further configured to transmit the CSI report to the BS, where
N 1 and N 2 respectively are number of antenna ports in first and second dimensions of the antenna port layout,
O 1 and O 2 are oversampling factors in first and second dimensions, respectively, and
an index pair (r 1 , r 2 ) indicates a beam group of the N 1 N 2 beam groups G(r 1 , r 2 ).
2. The UE of claim 1 , wherein the bitmap has the portion B (1) B (2) . . . B (N 1 N 2 ) of length 2N 1 N 2 , where B (i) =b 0 (i) b 1 (i) , is a bit-pair for an i-th beam group of the N 1 N 2 beam groups G(r 1 , r 2 ), and indicates the restriction on amplitude for each beam within the i-th beam group.
3. The UE of claim 2 , wherein values for the bit pair indicating the restriction on amplitude map to a maximum relative amplitude as
Bit-pair values
Maximum relative amplitude
00
0
01
{square root over (1/4)} = {square root over (0.25)}
10
{square root over (1/2)} = {square root over (0.5)}
11
1.
4. The UE of claim 2 , wherein the restriction on amplitude restricts maximum relative amplitude for all beams within the i-th beam group.
5. The UE of claim 1 , wherein the bitmap includes another portion indicating a restriction on rank indicator (RI) values for the CSI report.
6. The UE of claim 1 , wherein each beam group G(r 1 , r 2 ) corresponds to a vector group comprising L discrete Fourier transform (DFT) vectors.
7. The UE of claim 6 , wherein the N 1 N 2 vector groups are given by
G(r 1 , r 2 )={v O 1 r 1 +x 1 ,O 2 r 2 +x 2 : x 1 =0,1, . . . , O 1 −1; x 2 =0,1, . . . , O 2 −1} where r 1 ∈{0, 1, . . . , N 1 } and r 2 ∈{0, 1, . . . , N 2 } if N 2 >1,
G(r 1 , r 2 )={v O 1 r 1 +x 1 ,0 :x 1 =0,1, . . . , O 1 −1} where r 1 ∈{0, 1, . . . , N 1 } and r 2 =0 if N 2 =1, and
v l,m is a DFT vector such that
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
with
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
.
8. The UE of claim 1 , wherein O 1 =4 for a one-dimensional antenna port layout (N 2 =1) and O 1 =O 2 =4 for a two-dimensional antenna port layout (N 2 >1).
9. A base station (BS) for processing channel state information (CSI) reports in a wireless communication system, the BS comprising:
a transceiver configured to
transmit, to a user equipment (UE), a higher layer signaling including codebook subset restriction (CBSR) information including a bitmap having a portion indicating a restriction on N 1 N 2 beam groups G(r 1 , r 2 ) for an antenna port layout, wherein
a number of beams (L) are determined within each beam group of the N 1 N 2 beam groups G(r 1 , r 2 ), wherein L is O 1 for a one-dimensional antenna port layout (N 2 =1) and L is O 1 O 2 for a two-dimensional antenna port layout (N 2 >1), and
the restriction on N 1 N 2 beam groups G(r 1 , r 2 ) is identified based on the CB SR information, and
receive a CSI report from the UE determined based on the identified restriction on the N 1 N 2 beam groups G(r 1 , r 2 ), where
N 1 and N 2 respectively are number of antenna ports in first and second dimensions of the antenna port layout,
O 1 and O 2 are oversampling factors in first and second dimensions, respectively, and
an index pair (r 1 , r 2 ) indicates a beam group of the N 1 N 2 beam groups G(r 1 , r 2 ).
10. The BS of claim 9 , wherein the bitmap has the portion B (1) B (2) . . . B (N 1 N 2 ) of length 2N 1 N 2 , where B (i) =b 0 (i) b 1 (i) is a bit-pair for an i-th beam group of the N 1 N 2 beam groups G(r 1 , r 2 ), and indicates the restriction on amplitude for each beam within the i-th beam group.
11. The BS of claim 10 , wherein values for the bit pair indicating the restriction on amplitude map to a maximum relative amplitude as
Bit-pair values
Maximum relative amplitude
00
0
01
{square root over (1/4)} = {square root over (0.25)}
10
{square root over (1/2)} = {square root over (0.5)}
11
1.
12. The BS of claim 10 , wherein the restriction on amplitude restricts maximum relative amplitude for all beams within the i-th beam group.
13. The BS of claim 9 , wherein the bitmap includes another portion indicating a restriction on rank indicator (RI) values for the CSI report.
14. The BS of claim 9 , wherein each beam group G(r 1 , r 2 ) corresponds to a vector group comprising L discrete Fourier transform (DFT) vectors.
15. The BS of claim 14 , wherein the N 1 N 2 vector groups are given by
G(r 1 , r 2 )={v O 1 r 1 +x 1 ,O 2 r 2 +x 2 : x 1 =0,1, . . . , O 1 −1; x 2 =0,1, . . . , O 2 −1} where r 1 ∈{0, 1, . . . , N 1 } and r 2 ∈{0, 1, . . . , N 2 } if N 2 >1,
G(r 1 , r 2 )={v O 1 r 1 +x 1 ,0 : x 1 =0,1, . . . , O 1 −1} where r 1 ∈{0, 1, . . . , N 1 } and r 2 =0 if N 2 =1, and
v l,m is a DFT vector such that
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
with
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
.
16. The BS of claim 9 , wherein O 1 =4 for a one-dimensional antenna port layout (N 2 =1) and O 1 =O 2 =4 for a two-dimensional antenna port layout (N 2 >1).
17. A method within a user equipment (UE) for channel state information (CSI) reporting in a wireless communication system, the method comprising:
receiving, from a base station (BS), a higher layer signaling including codebook subset restriction (CBSR) information including a bitmap having a portion indicating a restriction on N 1 N 2 beam groups G(r 1 , r 2 ) for an antenna port layout; and
determining a number of beams (L) within each beam group of the N 1 N 2 beam groups G(r 1 , r 2 ), wherein L is O 1 for a one-dimensional antenna port layout (N 2 =1) and L is O 1 O 2 for a two-dimensional antenna port layout (N 2 >1);
identifying, based on the CBSR information, the restriction on N 1 N 2 beam groups G(r 1 , r 2 );
determining a CSI report based on the identified restriction on the N 1 N 2 beam groups G(r 1 , r 2 ); and
transmitting the CSI report to the BS, where
N 1 and N 2 respectively are number of antenna ports in first and second dimensions of the antenna port layout,
O 1 and O 2 are oversampling factors in first and second dimensions, respectively, and
an index pair (r 1 , r 2 ) indicates a beam group of the N 1 N 2 beam groups G(r 1 , r 2 ).
18. The method of claim 17 , wherein the bitmap has the portion B (1) B (2) . . . B (N 1 N 2 ) of length 2N 1 N 2 , where B (i) =b 0 (i) b 1 (i) is a bit-pair for an i-th beam group of the N 1 N 2 beam groups G(r 1 , r 2 ), and indicates the restriction on amplitude for each beam within the i-th beam group.
19. The method of claim 18 , wherein values for the bit pair indicating the restriction on amplitude map to a maximum relative amplitude as
Bit-pair values
Maximum relative amplitude
00
0
01
{square root over (1/4)} = {square root over (0.25)}
10
{square root over (1/2)} = {square root over (0.5)}
11
1.
20. The method of claim 18 , wherein the restriction on amplitude restricts maximum relative amplitude for all beams within the i-th beam group.
21. The method of claim 17 , wherein the bitmap includes another portion indicating a restriction on rank indicator (RI) values for the CSI report.
22. The method of claim 17 , wherein each beam group G(r 1 , r 2 ) corresponds to a vector group comprising L discrete Fourier transform (DFT) vectors.
23. The method of claim 22 , wherein the N 1 N 2 vector groups are given by
G(r 1 , r 2 )={v O 1 r 1 +x 1 ,O 2 r 2 +x 2 : x 1 =0,1, . . . , O 1 −1; x 2 =0,1, . . . , O 2 −1} where r 1 ∈{0, 1, . . . , N 1 } and r 2 ∈{0, 1, . . . , N 2 } if N 2 >1,
G(r 1 , r 2 )={v O 1 r 1 +x 1 ,0 : x 1 =0,1, . . . , O 1 −1} where r 1 ∈{0, 1, . . . , N 1 } and r 2 =0 if N 2 =1, and
v l,m is a DFT vector such that
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
with
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
.
24. The method of claim 17 , wherein O 1 =4 for a one-dimensional antenna port layout (N 2 =1) and O 1 =O 2 =4 for a two-dimensional antenna port layout (N 2 >1).