Method and apparatus for CSI reporting based on a window of basis vectors
Method and apparatuses for channel state information (CSI) reporting based on a window of basis vectors are provided. A method includes receiving a configuration about a CSI report including information about N TRP non-zero power (NZP) CSI-reference signal (RS) resources, where N TRP ≥1, and a parameter codebookType set to type-II-CJT-r18 or type-II-PortSelection-CJT-r18. The method further includes determining, for each layer l=1, . . . , v, an indicator for indicating an index of a strongest coefficient among K l NZ coefficients, where K l NZ is a total number of non-zero coefficients that are associated with Z NZP CSI-RS resources and Z≤N TRP , and a number of bits P l for the indicator. The method further includes transmitting the CSI report including, for each layer, P l bits for the indicator. When codebookType=type-II-CJT-r18, a value of P l depends on a value of K l NZ or a value of Σ r = 1 Z L r . When codebookType=type-II-PortSelection-CJT-r18, the value of P l depends on a value of 2 M v Σ r = 1 Z L r .
1 . A user equipment (UE) in a 3 rd generation partnership project (3GPP) communication system, the UE comprising:
a transceiver configured to receive a configuration about a channel state information (CSI) report, the configuration including information about (i) N TRP non-zero power (NZP) CSI-reference signal (RS) resources, where N TRP ≥1, and (ii) a parameter codebookType set to type-II-CJT-r18 or type-II-PortSelection-CJT-r18, where TRP is an abbreviation of transmit and receive point and CJT is an abbreviation of a coherent joint transmission; and
a processor operably coupled to the transceiver, the processor, based on the configuration, configured to determine, for each layer l=1, . . . , v:
an indicator i 1,8,l for indicating a strongest coefficient among
K
l
NZ
coefficients, where
K
l
NZ
is a total number of non-zero coefficients that are associated with Z NZP CSI-RS resources, and Z≤N TRP , and
wherein the transceiver is further configured to transmit the CSI report including, for each layer l=1, . . . , v, P l bits for the indicator i 1,8,l ,
wherein:
when codebookType=type-II-CJT-r18, a value of P l depends on:
a value of
K
l
NZ
,
when v=1, and
a value of
∑
r
=
1
Z
L
σ
r
,
when 1<v≤4, and
when codebookType=type-II-PortSelection-CJT-r18, the value of P l depends on a value of
2
M
υ
∑
r
=
1
Z
L
σ
r
for all values of v, and
wherein v is a rank, L σ r is a number of first vectors associated with an r-th NZP CSI-RS resource from the Z NZP CSI-RS resources, where r=1, . . . , Z, M v is a number of second vectors.
2 . The UE of claim 1 , wherein, when codebookType=type-II-CJT-r18:
P
l
=
P
1
=
⌈
log
2
K
1
NZ
⌉
when v= 1, and
P
l
=
⌈
log
2
(
2
∑
r
=
1
Z
L
σ
r
)
⌉
when 1< v≤ 4.
3 . The UE of claim 2 , wherein
i
1
,
8
,
l
∈
{
0
,
1
,
…
,
2
∑
r
=
1
Z
L
σ
r
-
1
}
and is obtained as:
i
1
,
8
,
l
=
{
∑
I
=
0
I
1
*
κ
1
I
,
0
(
3
)
-
1
v
=
1
I
l
*
1
<
v
≤
4
where:
κ
1
,
l
,
0
(
3
)
=
k
1
,
i
,
0
,
r
(
3
)
,
and I is an index given by
I
=
2
∑
k
=
1
r
-
1
L
σ
k
+
i
,
k
l
,
i
,
f
,
r
(
3
)
=
0
or 1 to indicate a coefficient with an index (i, f, r) being zero or non-zero, respectively,
I
l
*
∈
{
0
,
1
,
…
,
2
∑
r
=
1
Z
L
σ
r
-
1
}
and is given by
I
l
*
=
2
∑
k
=
1
r
l
*
-
1
L
σ
k
+
i
l
*
,
and
i
l
*
∈
{
0
,
…
,
2
L
r
l
*
-
1
}
,
and
r
l
*
∈
{
1
,
…
,
Z
}
.
4 . The UE of claim 1 , wherein, when codebookType=type-II-PortSelection-CJT-r18,
P
l
=
⌈
log
2
(
M
υ
∑
r
=
1
Z
K
1
,
r
)
⌉
.
5 . The UE of claim 4 , wherein
i
1
,
8
,
l
∈
{
0
,
1
,
…
,
2
M
υ
∑
r
=
1
Z
L
σ
r
-
1
}
and is obtained as:
i
1
,
8
,
l
=
f
l
*
∑
r
=
1
Z
K
1
,
r
+
I
l
*
where
I
l
*
∈
{
0
,
1
,
…
,
∑
r
=
1
z
K
1
,
r
-
1
}
and is given by
I
l
*
∈
∑
r
=
1
r
l
*
-
1
K
1
,
r
-
i
l
*
and K 1,r =2L r , and
i
l
*
∈
{
0
,
…
,
2
L
r
l
*
-
1
}
,
f
l
*
∈
{
0
,
1
,
…
,
M
v
-
1
}
,
and
r
l
*
∈
{
1
,
…
,
Z
}
.
6 . The UE of claim 1 , wherein, when codebookType=type-II-CJT-r18, the processor is further configured to, for each layer l:
remap indices of second vectors
n
3
,
l
(
f
)
,
where f=0, . . . , M v −1, with respect to
n
3
,
l
(
f
l
*
)
as
n
3
,
l
(
f
)
=
(
n
3
,
l
(
f
)
-
n
3
,
l
(
f
l
*
)
)
mod N 3 , such that
n
3
,
l
(
f
)
=
0
,
after remapping, and
remap each index f with respect to
f
l
*
as
f
=
(
f
-
f
l
*
)
mod
M
υ
,
such that
f
l
*
=
0
,
after remapping.
7 . The UE of claim 1 , wherein:
the configuration includes a parameter codebookMode, and
when codebookMode=mode1:
the processor is further configured to determine a second vector offset O r for each NZP CSI-RS resource such that O 1 =0, and O r ∈{0, 1, . . . , N 3 −1} for r=2, . . . , Z, and
the transceiver is further configured to transmit the CSI report including an indicator indicating a value of O r for each r∈{2, . . . , Z}.
8 . The UE of claim 1 , wherein:
when codebookType=type-II-CJT-r18, the first vectors comprise discrete Fourier transform (DFT) vectors,
when codebookType=type-II-PortSelection-CJT-r18, the first vectors comprise port selection vectors,
the second vectors comprise DFT vectors with indices belonging to a window of indices given by mod(M init +n, N 3 ), where n=0, 1, . . . , W−1, and W<N 3 ,
when codebookType=type-II-CJT-r18, the CSI report include an indicator indicating a value of M init , and
when codebookType=type-II-PortSelection-CJT-r18, M init =0.
9 . A base station (BS) in a 3 rd generation partnership project (3GPP) communication system, the BS comprising:
a processor; and
a transceiver operably coupled to the processor, the transceiver configured to:
transmit a configuration about a channel state information (CSI) report, the configuration including information about (i) N TRP non-zero power (NZP) CSI-reference signal (RS) resources, where N TRP ≥1, and (ii) a parameter codebookType set to type-II-CJT-r18 or type-II-PortSelection-CJT-r18, where TRP is an abbreviation of transmit and receive point and CJT is an abbreviation of a coherent joint transmission; and
receive the CSI report including, for each layer l=1, . . . , v, a P l bits for an indicator i 1,8,l , wherein the indicator i 1,8,l is for indicating a strongest coefficient among
K
l
NZ
coefficients, where
K
l
NZ
is a total number of non-zero coefficients that are associated with Z NZP CSI-RS resources, and Z≤N TRP ,
wherein:
when codebookType=type-II-CJT-r18, a value of P l depends on:
a value of
K
l
NZ
,
when v=1, and
a value of
∑
r
=
1
Z
L
σ
r
,
when 1<v≤4, and
when codebookType=type-II-PortSelection-CJT-r18, the value of P l depends on a value of
2
M
υ
∑
r
=
1
Z
L
σ
r
,
for all values of v, and
wherein v is a rank L σ r is a number of first vectors associated an r-th NZP CSI-RS resource from the Z NZP CSI-RS resources, where r=1, . . . , Z, M v is a number of second vectors.
10 . The BS of claim 9 , wherein, when codebookType=type-II-CJT-r18:
P
l
=
P
1
=
⌈
log
2
(
K
1
NZ
)
⌉
when v= 1, and
P
l
=
⌈
log
2
(
2
∑
r
=
1
Z
L
σ
r
)
⌉
when 1< v≤ 4.
11 . The BS of claim 10 , wherein
i
1
,
8
,
l
∈
{
0
,
1
,
…
,
2
∑
r
=
1
Z
L
σ
r
-
1
}
and is obtained as:
i
1
,
8
,
l
=
{
∑
I
=
0
I
1
*
κ
1
,
I
,
0
(
3
)
-
1
v
=
1
I
l
*
1
<
v
≤
4
where:
κ
1
,
I
,
0
(
3
)
=
k
1
,
i
,
0
,
r
(
3
)
,
and I is an index given by
I
=
2
∑
k
=
1
r
-
1
L
σ
k
+
i
,
k
l
,
i
,
f
,
r
(
3
)
=
0
or
1
to indicate a coefficient with an index (i, f, r) being zero or non-zero, respectively,
I
l
*
∈
{
0
,
1
,
…
,
2
∑
r
=
1
Z
L
σ
r
-
1
}
and is given by
I
l
*
=
2
∑
k
=
1
r
l
*
-
1
L
σ
k
+
i
l
*
,
and
i
l
*
∈
{
0
,
…
,
2
L
r
l
*
-
1
}
,
and
r
l
*
∈
{
1
,
…
,
Z
}
.
12 . The BS of claim 9 , wherein, when codebookType=type-II-PortSelection-CJT-r18,
P
l
=
⌈
log
2
(
M
υ
∑
r
=
1
Z
K
1
,
r
)
⌉
.
13 . The BS of claim 12 , wherein
i
1
,
8
,
l
∈
{
0
,
1
,
…
,
2
M
υ
∑
r
=
1
Z
L
σ
r
-
1
}
and is obtained as:
i
1
,
8
,
l
=
f
l
*
∑
r
=
1
Z
K
1
,
r
+
I
l
*
where
I
l
*
∈
{
0
,
1
,
…
,
∑
r
=
1
Z
K
1
,
r
-
1
}
and is given by
I
l
*
=
∑
r
=
1
r
l
*
-
1
K
1
,
r
+
i
l
*
and K 1,r =2L r , and
i
l
*
∈
{
0
,
…
,
2
L
r
l
*
-
1
}
,
f
l
*
∈
{
0
,
1
,
…
,
M
v
-
1
}
,
and
r
l
*
∈
{
1
,
…
,
Z
}
.
14 . The BS of claim 9 , wherein, when codebookType=type-II-CJT-r18, for each layer l:
indices of second vectors
n
3
,
l
(
f
)
,
where f=0, . . . , M v −1, are remapped with respect to
n
3
,
l
(
f
l
*
)
as
n
3
,
l
(
f
)
=
(
n
3
,
l
(
f
)
-
n
3
,
l
(
f
l
*
)
)
mod N 3 , such that
n
3
,
l
(
f
l
*
)
=
0
,
after remapping, and
each index f is remapped with respect to
f
l
*
as
f
=
(
f
-
f
l
*
)
mod M v , such that
f
l
*
=
0
,
after remapping.
15 . The BS of claim 9 , wherein:
the configuration includes a parameter codebookMode, and
when codebookMode=mode1, the transceiver is further configured to receive the CSI report including an indicator indicating a value of a second vector offset O r for each NZP CSI-RS resource such that O 1 =0, and O r ∈{0, 1, . . . , N 3 −1} for r=2, . . . , Z.
16 . The BS of claim 9 , wherein:
when codebookType=type-II-CJT-r18, the first vectors comprise discrete Fourier transform (DFT) vectors,
when codebookType=type-II-PortSelection-CJT-r18, the first vectors comprise port selection vectors,
the second vectors comprise DFT vectors with indices belonging to a window of indices given by mod(M init +n, N 3 ), where n=0, 1, . . . , W−1, and W<N 3 ,
when codebookType=type-II-CJT-r18, the CSI report includes an indicator indicating a value of M init , and
when codebookType=type-II-PortSelection-CJT-r18, M init =0.
17 . A method performed by a user equipment (UE) in a 3 rd generation partnership project (3GPP) communication system, the method comprising:
receiving a configuration about a channel state information (CSI) report, the configuration including information about (i) N TRP non-zero power (NZP) CSI-reference signal (RS) resources, where N TRP ≥1, and (ii) a parameter codebookType set to type-II-CJT-r18 or type-II-PortSelection-CJT-r18, where TRP is an abbreviation of transmit and receive point and CJT is an abbreviation of a coherent joint transmission;
determining, based on the configuration, for each layer l=1, . . . , v:
an indicator i 1,8,l for indicating a strongest coefficient among
K
l
NZ
coefficients, where
K
l
NZ
is a total number of non-zero coefficients that are associated with Z NZP CSI-RS resources, and Z≤N TRP ,
transmitting the CSI report including, for each layer l=1, . . . , v, P l bits for the indicator i 1,8,l ,
wherein:
when codebookType=type-II-CJT-r18, a value of P l depends on:
a value of
K
l
NZ
,
when v=1, and
a value of
∑
r
=
1
Z
L
σ
r
,
when 1<v≤4, and
when codebookType=type-II-PortSelection-CJT-r18, the value of P l depends on a value of
2
M
υ
∑
r
=
1
Z
L
σ
r
for all values of v, and
wherein v is a rank, L σ r is a number of first vectors associated with an r-th NZP CSI-RS resource from the Z NZP CSI-RS resources, where r=1, . . . , Z, M v is a number of second vectors.
18 . The method of claim 17 , wherein, when codebookType=type-II-CJT-r18:
P
l
=
P
1
=
⌈
log
2
K
1
NZ
⌉
when v= 1, and
P
l
=
⌈
log
2
(
2
∑
r
=
1
Z
L
σ
r
)
⌉
when 1< v≤ 4.
19 . The method of claim 18 , wherein
I
=
2
∑
k
=
1
r
-
1
L
σ
k
+
i
and is obtained as:
i
1
,
8
,
l
=
{
∑
I
=
0
I
1
*
κ
1
,
I
,
0
(
3
)
-
1
υ
=
1
I
l
*
1
<
υ
≤
4
where:
κ
1
,
I
,
0
(
3
)
=
k
1
,
i
,
0
,
r
(
3
)
,
and I is an index given by
I
=
2
∑
k
=
1
r
-
1
L
σ
k
+
i
,
k
l
,
i
,
f
,
r
(
3
)
=
0
or 1 to indicate a coefficient with an index (i, f, r) being zero or non-zero, respectively,
I
l
*
∈
{
0
,
1
,
…
,
2
∑
r
=
1
Z
L
σ
r
-
1
}
and is given by
I
l
*
=
2
∑
k
=
1
r
l
*
-
1
L
σ
k
+
i
l
*
,
and
i
l
*
∈
{
0
,
…
,
2
L
r
l
*
-
1
}
,
and
r
l
*
∈
{
1
,
…
,
Z
}
.
20 . The method of claim 17 , wherein, when codebookType=type-II-PortSelection-CJT-r18,
P
l
=
⌈
log
2
(
M
υ
∑
r
=
1
Z
K
1
,
r
)
⌉
.