Method for operating SL DRX in consideration of mode 1 operation of transmission terminal in NR V2X

1 . A method comprising:

receiving, by a first device, from a second device, a sidelink (SL) discontinuous reception (DRX) configuration including information related to a SL DRX onduration timer, information related to a SL DRX hybrid automatic repeat request (HARQ) round trip time (RTT) timer and information related to a SL DRX retransmission timer,

wherein a time duration that the SL DRX onduration timer or the SL DRX retransmission timer runs is included in an active time of the first device;

receiving, by the first device, from the second device, information related to whether a physical uplink control channel (PUCCH) resource is configured and information related to resource allocation mode;

determining, by the first device, a value of the SL DRX HARQ RTT timer, based on the information related to whether a PUCCH resource is configured and the information related to resource allocation mode;

receiving, by the first device, from the second device, sidelink control information (SCI) for scheduling of a physical sidelink shared channel (PSSCH), through physical sidelink control channel (PSCCH), in the active time,

wherein the SCI includes resource information related to a first resource in which the SCI is received and a second resource after the first resource, and

wherein the second resource exists within a time duration after expiration of the SL DRX onduration timer;

determining, by the first device, decoding failure for a medium access control (MAC) protocol data unit (PDU) transmitted, from the second device, through the PSSCH;

transmitting, by the first device, to the second device, HARQ negative acknowledge (NACK) related to the MAC PDU through a physical sidelink feedback channel (PSFCH) related to the PSSCH, based on the decoding failure;

starting, by the first device, the SL DRX HARQ RTT timer based on the value;

starting, by the first device, the SL DRX retransmission timer, based on expiration of the SL DRX HARQ RTT timer, and

receiving, by the first device, from the second device, a retransmission of the MAC PDU based on a retransmission resource.

2 . The method of claim 1 , wherein the information related to whether a PUCCH resource is configured and the information related to resource allocation mode are received through the SCI.

3 . The method of claim 1 , wherein the SL DRX HARQ RTT timer is started based on the SL DRX HARQ RTT timer value and the transmission of the HARQ NACK.

4 . The method of claim 1 , wherein the information related to whether a PUCCH resource is configured represents that a PUCCH resource is configured to the second device,

wherein the information related to resource allocation mode represents that the resource allocation mode is mode 1,

wherein a resource allocation request for the retransmission resource is transmitted, to a base station, through the PUCCH resource between a first time point of the second device receiving the HARQ NACK through the PSFCH and a second time point of the second device retransmitting, to the first device, the MAC PDU,

wherein the retransmission resource is an allocated resource allocated from the base station, based on the resource allocation request, and

wherein the timer value is a minimum time gap between the first time point and the second time point.

5 . The method of claim 4 , wherein the resource allocation request is performed based on decoding for the PSFCH by the second device.

6 . The method of claim 1 , wherein the information related to whether a PUCCH resource is configured represents that a PUCCH resource is not configured to the second device,

wherein the information related to resource allocation mode represents that the resource allocation mode is mode 1, and

wherein the timer value is a minimum time gap between a first time point of the second device receiving the HARQ NACK through the PSFCH and a second time point of the second device retransmitting, to the first device, the MAC PDU.

7 . The method of claim 1 , wherein the retransmission of the MAC PDU is received based on the first device being in active mode.

8 . The method of claim 1 , wherein the information related to resource allocation mode represents that the resource allocation mode is mode 2,

wherein the timer value is a minimum time gap between a first time point of the second device receiving the HARQ NACK through the PSFCH and a second time point of the second device retransmitting, to the first device, the MAC PDU.

9 . The method of claim 1 , wherein the SCI includes information representing that a HARQ feedback for the MAC PDU is enabled.

10 . The method of claim 1 , wherein the SCI includes information representing that a HARQ feedback for the MAC PDU is disabled.

11 . The method of claim 1 , wherein the SL DRX HARQ RTT timer is started based on the existence of the second resource within the time duration after the expiration of the on-duration timer and the SL DRX HARQ RTT timer value.

12 . A first device comprising:

one or more memories storing instructions;

one or more transceivers; and

one or more processors connected to the one or more memories and the one or more transceivers, wherein the one or more processors execute the instructions to:

receive, from a second device, a sidelink (SL) discontinuous reception (DRX) configuration including information related to a SL DRX onduration timer, information related to a SL DRX hybrid automatic repeat request (HARQ) round trip time (RTT) timer and information related to a SL DRX retransmission timer,

wherein a time duration that the SL DRX onduration timer or the SL DRX retransmission timer runs is included in an active time of the first device;

receive, from the second device, information related to whether a physical uplink control channel (PUCCH) resource is configured and information related to resource allocation mode;

determine a value of the SL DRX HARQ RTT timer, based on the information related to whether a PUCCH resource is configured and the information related to resource allocation mode;

receive, from the second device, sidelink control information (SCI) for scheduling of a physical sidelink shared channel (PSSCH), through physical sidelink control channel (PSCCH), in the active time,

wherein the SCI includes resource information related to a first resource in which the SCI is received and a second resource after the first resource, and

wherein the second resource exists within a time duration after expiration of the SL DRX onduration timer;

determine decoding failure for a medium access control (MAC) protocol data unit (PDU) transmitted, from the second device, through the PSSCH;

transmit, to the second device, HARQ negative acknowledge (NACK) related to the MAC PDU through a physical sidelink feedback channel (PSFCH) related to the PSSCH, based on the decoding failure;

start the SL DRX HARQ RTT timer based on the value;

start the SL DRX retransmission timer, based on expiration of the SL DRX HARQ RTT timer; and

receive, from the second device, a retransmission of the MAC PDU based on a retransmission resource.

13 . A device adapted to control a first user equipment (UE), the device comprising:

one or more processors; and

one or more memories operably connectable to the one or more processors and storing instructions, wherein the one or more processors execute the instructions to:

receive, from a second UE, a sidelink (SL) discontinuous reception (DRX) configuration including information related to a SL DRX onduration timer, information related to a SL DRX hybrid automatic repeat request (HARQ) round trip time (RTT) timer and information related to a SL DRX retransmission timer,

wherein a time duration that the SL DRX onduration timer or the SL DRX retransmission timer runs is included in an active time of the first device;

receive, from the second UE, information related to whether a physical uplink control channel (PUCCH) resource is configured and information related to resource allocation mode;

determine a value of the SL DRX HARQ RTT timer, based on the information related to whether a PUCCH resource is configured and the information related to resource allocation mode;

receive, from the second device, sidelink control information (SCI) for scheduling of a physical sidelink shared channel (PSSCH), through physical sidelink control channel (PSCCH), in the active time,

wherein the SCI includes resource information related to a first resource in which the SCI is received and a second resource after the first resource, and

wherein the second resource exists within a time duration after expiration of the SL DRX onduration timer;

determine decoding failure for a medium access control (MAC) protocol data unit (PDU) transmitted, from the second device, through the PSSCH;

transmit, to the second device, HARQ negative acknowledge (NACK) related to the MAC PDU through a physical sidelink feedback channel (PSFCH) related to the PSSCH, based on the decoding failure;

start the SL DRX HARQ RTT timer based on the value; and

start the SL DRX retransmission timer, based on expiration of the SL DRX HARQ RTT timer; and

receive, from the second device, a retransmission of the MAC PDU based on a retransmission resource.