Sidelink transport block size calculation scheme and associated apparatuses, systems, and methods
Apparatuses, systems, and methods may determine a transport block size using a number of resource elements for sidelink data. The number of resource elements for the sidelink data is calculated based at least on a reference second stage Sidelink Control Information (SCI) overhead. The reference second stage SCI overhead is calculated using the reference coding rate, the reference beta offset, the reference PSFCH symbol number, the alpha value, and the second stage SCI payload size.
1. An apparatus for a user equipment (UE), comprising:
a memory interface to access a first stage Sidelink Control Information (SCI) indicating a second stage SCI payload size, a second stage SCI, and a resource pool configuration including a reference coding rate, a reference modulation order, a reference beta offset, a reference channel-state information reference signal (CSI-RS) port number, a reference Physical Sidelink Feedback Channel (PSFCH) symbol number, and an alpha value;
a baseband processor to:
calculate a reference second stage SCI overhead using the reference coding rate, the reference beta offset, the reference PSFCH symbol number, the alpha value, and the second stage SCI payload size; and
calculate a number of resource elements for a physical sidelink shared channel (PSSCH) based at least on the reference second stage SCI overhead.
2. The apparatus of claim 1 , wherein the reference second stage SCI overhead is calculated by solving a reference second stage SCI formula, wherein the reference second stage SCI formula is:
N
RE
SCI
2
=
min
{
⌈
(
O
SCI
2
+
L
SCI
2
)
β
offset
SCI
2
R
*
Q
m
⌉
,
⌈
α
∑
l
=
0
N
symbol
SCI
-
2
-
1
M
S
C
SCI
2
(
l
)
⌉
}
+
γ
where:
O SCI2 is the second stage SCI payload size,
L SCI2 is a Cyclic Redundancy Check (CRC) length of second stage SCI,
R is the reference coding rate,
Q m =2 is the reference modulation order,
α is the alpha value and is a scaling value per resource pool,
N symbol SCI-2 is a number of symbols for potential SCI stage 2 transmissions, depending on a number of reference PSFCH symbols,
M SC SCI2 (l) is a scheduled bandwidth of PSSCH transmission,
γ is a value to ensure the reference second stage SCI overhead occupies an integer number of resource blocks,
β offset SCI2 is the reference beta offset.
3. The apparatus of claim 2 , wherein γ is not used in the reference second stage SCI formula.
4. The apparatus of claim 1 , wherein the baseband processor is further to determine a CSI-RS overhead using on cast type and the reference CSI-RS port number,
wherein to determine the CSI-RS overhead the baseband processor is to obtain a format of second stage SCI from the first stage SCI,
wherein for sidelink broadcast and groupcast, the CSI-RS overhead is zero, and
wherein for sidelink unicast the CSI-RS overhead depends on the reference CSI-RS port number.
5. The apparatus of claim 1 , wherein the baseband processor is further to determine a phase-tracking reference signal (PTRS) overhead using a reference modulation coding scheme (MCS) determined based on the reference coding rate and the reference modulation order, wherein a time density of the PTRS overhead depends on the reference MCS.
6. The apparatus of claim 1 , wherein the baseband processor is further to determine a PSFCH overhead using the reference PSFCH symbol number;
wherein the PSFCH overhead is a total number of resource elements allocated for PSFCH transmissions and a guard period symbol before the PSFCH transmissions, wherein the PSFCH overhead depends on configured PSFCH periodicity.
7. The apparatus of claim 1 , wherein the baseband processor is further to determine a PSSCH demodulation reference signal (DMRS) overhead using the reference PSFCH symbol number, wherein to determine the PSSCH DMRS overhead the baseband processor is to derive a reference DMRS symbol number from the reference PSFCH symbol number and preconfigured DMRS time patterns.
8. The apparatus of claim 1 , wherein the baseband processor is further to calculate a physical sidelink control channel (PSCCH) overhead, wherein the PSCCH overhead is a total number of resource elements allocated for PSCCH.
9. The apparatus of claim 1 , wherein the baseband processor is further to calculate an intermediate number of information bits using the number of resource elements for the PSSCH, and
determine a transport block size using the intermediate number of information bits.
10. The apparatus of claim 1 , wherein to calculate the number of resource elements for the PSSCH the baseband processor reduces a total number of resource elements for both PSSCH transmissions and physical sidelink control channel (PSCCH)transmissions by the reference second stage SCI overhead, a CSI-RS overhead, a phase-tracking reference signal (PTRS) overhead, a PSFCH overhead, a PSSCH demodulation reference signal (DMRS)overhead, and a PSCCH overhead.
11. The apparatus of claim 1 , wherein to calculate the number of resource elements for the PSSCH the baseband processor uses an equation:
N RE =N RE PSSCH/PSSCH −N RE PSSCH −N RE SCI2 −N RE PSFCH −N RE PSSCH-DMRS −N RE PTRS −N RE CSI-RS
where:
N RE PSCCH/PSSCH is a total number resource elements allocated for physical sidelink control channel (PSCCH)/PSSCH transmissions;
N RE PSCCH is a PSCCH overhead;
N RE SCI2 is the reference second stage SCI overhead;
N RE PSFCH is a PSFCH overhead;
N RE PSSCH-DMRS is a PSSCH demodulation reference signal (DMRS) overhead;
N RE PTRS is a phase-tracking reference signal (PTRS) overhead;
N RE CSI-RS is a CSI-RS overhead.
12. A method for a user equipment (UE), comprising:
receiving a resource pool configuration including a reference coding rate, a reference modulation order, a reference beta offset, a reference channel-state information reference signal (CSI-RS) port number, a reference Physical Sidelink Feedback Channel (PSFCH) symbol number, an alpha value, and a reference modulation coding scheme (MCS);
receiving a first stage Sidelink Control Information (SCI) indicating a second stage SCI payload size;
receiving a second stage SCI;
calculating a reference second stage SCI overhead using the reference coding rate, the reference beta offset, the reference PSFCH symbol number, the alpha value, and the second stage SCI payload size; and
calculating a number of resource elements for a physical sidelink shared channel (PSSCH) based at least on the reference second stage SCI overhead.
13. The method of claim 12 , wherein the reference second stage SCI overhead is calculated by solving a reference second stage SCI formula, wherein the reference second stage SCI formula is:
N
RE
SCI
2
=
min
{
⌈
(
O
SCI
2
+
L
SCI
2
)
β
offset
SCI
2
R
*
Q
m
⌉
,
⌈
α
∑
l
=
0
N
symbol
SCI
-
2
-
1
M
S
C
SCI
2
(
l
)
⌉
}
+
γ
where:
O SCI2 is the second stage SCI payload size,
L SCI2 is a Cyclic Redundancy Check (CRC) length of second stage SCI,
R is the reference coding rate,
Q m =2 is the reference modulation order,
α is the alpha value and is a scaling value per resource pool,
N symbol SCI-2 is a number of symbols for potential SCI stage 2 transmissions, depending on a number of reference PSFCH symbols,
M SC SCI2 (l) is a scheduled bandwidth of PSSCH transmission,
γ is a value to ensure the reference second stage SCI overhead occupies an integer number of resource blocks,
β offset SCI2 is the reference beta offset.
14. The method of claim 13 , wherein γ is not used in the reference second stage SCI formula.
15. The method of claim 12 , further comprising determining a CSI-RS overhead using on cast type and the reference CSI-RS port number,
wherein to determining the CSI-RS overhead comprises obtaining a format of second stage SCI from the first stage SCI and obtaining cast-type from the second stage SCI,
wherein for sidelink broadcast and groupcast, the CSI-RS overhead is zero, and
wherein for sidelink unicast the CSI-RS overhead depends on the reference CSI-RS port number.
16. The method of claim 12 , further comprising determining a phase-tracking reference signal (PTRS) overhead using the reference MCS, wherein time density of the PTRS overhead depends on the reference MCS.
17. The method of claim 12 , further comprising determining a PSFCH overhead using the reference PSFCH symbol number, wherein the PSFCH overhead is a total number of resource elements allocated for PSFCH transmissions and a guard period symbol before the PSFCH transmissions, wherein the PSFCH overhead depends on configured PSFCH periodicity.
18. A non-transitory computer-readable storage medium, the computer-readable storage medium including instructions that when executed by a UE, cause the UE to:
receive a resource pool configuration including a reference coding rate, a reference modulation order, a reference beta offset, a reference channel-state information reference signal (CSI-RS) port number, a reference Physical Sidelink Feedback Channel (PSFCH) symbol number, an alpha value, and a reference modulation coding scheme (MCS);
receive a first stage Sidelink Control Information (SCI) indicating a second stage SCI payload size;
receive a second stage SCI;
calculate a reference second stage SCI overhead using the reference coding rate, the reference beta offset, the reference PSFCH symbol number, the alpha value, and the second stage SCI payload size; and
calculate a number of resource elements for a physical sidelink shared channel (PSSCH) based at least on the reference second stage SCI overhead.
19. The computer-readable storage medium of claim 18 , wherein the reference second stage SCI overhead is calculated by solving a reference second stage SCI formula, wherein the reference second stage SCI formula is:
N
RE
SCI
2
=
min
{
⌈
(
O
SCI
2
+
L
SCI
2
)
β
offset
SCI
2
R
*
Q
m
⌉
,
⌈
α
∑
l
=
0
N
symbol
SCI
-
2
-
1
M
S
C
SCI
2
(
l
)
⌉
}
+
γ
where:
O SCI2 is the second stage SCI payload size,
L SCI2 is the Cyclic Redundancy Check (CRC) length of second stage SCI,
R is the reference coding rate,
Q m =2 is the reference modulation order,
α is the alpha value and is a scaling value per resource pool,
N symbol SCI-2 is a number of symbols for potential SCI stage 2 transmissions, depending on a number of reference PSFCH symbols
M SC SCI2 (l) is a scheduled bandwidth of PSSCH transmission,
γ is a value to ensure the reference second stage SCI overhead occupies an integer number of resource blocks,
β offset SCI2 is the reference beta offset.
20. The computer-readable storage medium of claim 19 , wherein γ is not used in the reference second stage SCI formula.