HARQ operation and power control in sidelink
User equipments (UEs) and methods for hybrid automatic repeat request acknowledgement (HARQ-ACK) operation in a sidelink. A user equipment configured to receive a physical sidelink control channel (PSCCH) that includes a sidelink control information (SCI) format scheduling a reception of a physical sidelink shared channel (PSSCH) that includes a transport block (TB) and to provide HARQ-ACK information for the TB decoding in a physical sidelink feedback channel (PSFCH).
1. A method for operating a user equipment (UE), the method comprising:
receiving:
a physical sidelink control channel (PSCCH) that includes a sidelink control information (SCI) format scheduling a reception of a physical sidelink shared channel (PSSCH), and
the PSSCH that includes a transport block (TB);
decoding the TB;
determining whether or not to transmit hybrid automatic repeat request acknowledgement (HARQ-ACK) information for the decoded TB in a physical sidelink feedback channel (PSFCH) based on:
information by higher layers indicating whether resources for a PSFCH transmission are available or unavailable, and
an indication by a field in the SCI format responsive to a determination that the information indicates availability of the resources for the PSFCH transmission; and
transmitting or not transmitting the PSFCH with the HARQ-ACK information based on a result of the determination,
wherein the UE does not transmit the PSFCH with the HARQ-ACK information when the resources for the PSFCH transmission are indicated as unavailable even when the field indicates reporting of the HARQ-ACK information.
2. The method of claim 1 , further comprising determining:
a PSSCH reception type to be groupcast based on a destination identity field in the SCI format; and
a HARQ-ACK reporting type, based on a field in the SCI format, to be either a first HARQ-ACK reporting type or a second HARQ-ACK reporting type and the HARQ-ACK information has a NACK value.
3. The method of claim 1 , further comprising determining:
a PSSCH reception type to be groupcast based on a destination identity field in the SCI format; and
a location enabling transmission of the PSFCH based on a location indication field in the SCI format.
4. The method of claim 1 , further comprising determining a PSFCH transmission power P PSFCH as:
P
P
S
F
C
H
=
min
{
P
C
MAX
,
P
O
_
PSFCH
,
Uu
+
10
log
10
(
2
μ
×
M
PSFCH
)
+
α
Uu
×
PL
Uu
}
,
wherein:
P CMAX is a maximum transmission power,
M PSFCH is a number of resource blocks and μ is a subcarrier spacing (SCS) configuration for the PSFCH transmission,
P O_PSFCH,Uu is a power value provided by higher layers,
α Uu is a scaling factor provided by higher layers,
PL Uu is a pathloss that is calculated from a downlink reception, and
transmitting the PSFCH comprises transmitting the PSFCH with P PSFCH power.
5. The method of claim 4 , further comprising:
receiving a configuration for first and second values of P O_PSFCH,Uu ;
determining a PSSCH reception type to be either unicast or groupcast based on a destination identity field in the SCI format; and
transmitting the PSFCH using the first P O_PSFCH,Uu value when the PSSCH reception type is unicast and using the second P O_PSFCH,Uu value when the PSSCH reception type is groupcast.
6. The method of claim 1 , further comprising:
determining a PSFCH transmission power P PSFCH as P PSFCH =P CMAX responsive to a determination that a power value P O_PSFCH,Uu is not provided by higher layers for a determination of a PSFCH transmission power, wherein P CMAX is a maximum transmission power,
wherein transmitting the PSFCH comprises transmitting the PSFCH with P PSFCH power.
7. The method of claim 1 , further comprising:
determining a PSSCH reception type to be groupcast based on a destination identity field in the SCI format,
wherein transmitting the PSFCH comprises transmitting the PSFCH with a larger power for a second HARQ-ACK reporting type than for a first HARQ-ACK reporting type.
8. A user equipment (UE) comprising:
a receiver configured to receive:
a physical sidelink control channel (PSCCH) that includes a sidelink control information (SCI) format scheduling a reception of a physical sidelink shared channel (PSSCH), and
the PSSCH that includes a transport block (TB);
a processor operably connected to the receiver, the processor configured to decode the TB and determine whether or not to transmit hybrid automatic repeat request acknowledgement (HARQ-ACK) information for the decoded TB in a physical sidelink feedback channel (PSFCH) based on:
information by higher layers indicating whether resources for a PSFCH transmission are available or unavailable, and
an indication by a field in the SCI format responsive to a determination that the configuration indicates availability of the resources for the PSFCH transmission; and
a transmitter operably connected to the processor, the transmitter configured to transmit or not transmit the PSFCH with the HARQ-ACK information based on a result of the determination,
wherein the transmitter does not transmit the PSFCH with the HARQ-ACK information when the resources for the PSFCH transmission are indicated as unavailable even when the field indicates reporting of the HARQ-ACK information.
9. The UE of claim 8 , wherein the processor is further configured to determine:
a PSSCH reception type to be groupcast based on a destination identity field in the SCI format; and
a HARQ-ACK reporting type, based on a field in the SCI format, to be either a first HARQ-ACK reporting type or a second HARQ-ACK reporting type and the HARQ-ACK information has a NACK value.
10. The UE of claim 8 , wherein the processor is further configured to determine:
a PSSCH reception type to be groupcast based on a destination identity field in the SCI format; and
a location enabling transmission of the PSFCH based on a location indication field in the SCI format.
11. The UE of claim 8 , wherein:
the processor is further configured to determine a PSFCH transmission power P PSFCH as
P
P
S
F
C
H
=
min
{
P
C
MAX
,
P
O
_
PSFCH
,
Uu
+
10
log
10
(
2
μ
×
M
PSFCH
)
+
α
Uu
×
PL
Uu
}
,
P CMAX is a maximum transmission power,
M PSFCH is a number of resource blocks and μ is a subcarrier spacing (SCS) configuration for the PSFCH transmission,
P O_PSFCH,Uu is a power value provided by higher layers,
α Uu is a scaling factor provided by higher layers,
PL Uu is a pathloss that is calculated from a downlink reception; and
the transmitter is configured to transmit the PSFCH with P PSFCH power.
12. The UE of claim 11 , wherein:
the receiver is further configured to receive a configuration for first and second values of P O_PSFCH,Uu ;
the processor is further configured to determine a PSSCH reception type to be either unicast or groupcast based on a destination identity field in the SCI format; and
the transmitter is configured to transmit the PSFCH using the first P O_PSFCH,Uu value when the PSSCH reception type is unicast and using the second P O_PSFCH,Uu value when the PSSCH reception type is groupcast.
13. The UE of claim 8 , wherein:
the processor is further configured to determine a PSFCH transmission power P PSFCH as P PSFCH =P CMAX responsive to a determination that a power value P O_PSFCH,Uu is not provided by higher layers for a determination of a PSFCH transmission power, wherein P CMAX is a maximum transmission power; and
the transmitter is further configured to transmit the PSFCH with P PSFCH power.
14. The UE of claim 8 , wherein:
the processor is further configured to determine a PSSCH reception type to be groupcast based on a destination identity field in the SCI format; and
the transmitter is configured to transmit the PSFCH with a larger power for a second HARQ-ACK reporting type than for a first HARQ-ACK reporting type.
15. A user equipment (UE) comprising:
a transmitter configured to transmit:
a physical sidelink control channel (PSCCH) that includes a sidelink control information (SCI) format scheduling a reception of a physical sidelink shared channel (PSSCH), and
the PSSCH that includes a transport block (TB);
a processor operably connected to the transmitter, the processor configured to determine whether or not to receive hybrid automatic repeat request acknowledgement (HARQ-ACK) information for the TB in a physical sidelink feedback channel (PSFCH) based on:
information by higher layers indicating whether resources for a PSFCH transmission are available or unavailable, and
an indication by a field in the SCI format responsive to a determination that the configuration indicates availability of the resources for the PSFCH transmission; and
a receiver operably connected to the processor, the receiver configured to receive or not receive the PSFCH with the HARQ-ACK information based on a result of the determination,
wherein the receiver does not receive the PSFCH with the HARQ-ACK information when the resources for the PSFCH transmission are indicated as unavailable even when the field indicates reporting of the HARQ-ACK information.
16. The UE of claim 15 , wherein the processor is further configured to determine:
a PSSCH reception type to be groupcast based on a destination identity field in the SCI format; and
a HARQ-ACK reporting type, based on a field in the SCI format, to be either a first HARQ-ACK reporting type or a second HARQ-ACK reporting type and the HARQ-ACK information has a NACK value.
17. The UE of claim 15 , wherein the processor is further configured to determine:
a PSSCH reception type to be groupcast based on a destination identity field in the SCI format; and
a location enabling transmission of the PSFCH based on a location indication field in the SCI format.
18. The UE of claim 15 , wherein the transmitter is further configured to transmit the received HARQ-ACK information in a physical uplink control channel (PUCCH).
19. The UE of claim 15 , wherein the transmitter is further configured to transmit the PSCCH and the PSSCH with a same energy per resource element.
20. The UE of claim 15 , wherein:
the transmitter is further configured to transmit a channel state information reference signal (CSI-RS), and
a transmission power for transmission of the CSI-RS is determined from a PSSCH transmission power, a number of PSSCH transmission layers, and a number of CSI-RS antenna ports.