Method and apparatus for performing SL DRX operation in NR V2X

1 . A method comprising:

obtaining, by a first device, an inter-user equipment (inter-UE) link discontinuous reception (DRX) configuration including an inter-UE DRX inactivity timer, an inter-UE DRX hybrid automatic repeat request (HARQ) round-trip time (RTT) timer, and an inter-UE DRX retransmission timer;

receiving, by the first device, first inter-UE control information for scheduling of a first inter-UE physical shared channel and second inter-UE control information from a second device through a first inter-UE physical control channel;

receiving, by the first device, the second inter-UE control information and a first medium access control (MAC) protocol data unit (PDU) from the second device through the first inter-UE physical shared channel;

starting, by the first device, the inter-UE DRX inactivity timer;

transmitting, by the first device, inter-UE HARQ feedback information to the second device through an inter-UE physical feedback channel on an inter-UE physical feedback channel resource determined based on a slot index and a sub-channel index related to the first inter-UE physical shared channel; and

based on that the second inter-UE control information is related to groupcast, restarting, by the first device, the inter-UE DRX inactivity timer after the inter-UE physical feedback channel resource.

2 . The method of claim 1 , wherein, based on that the second inter-UE control information is related to the groupcast and the inter-UE DRX inactivity timer is running, the inter-UE DRX inactivity timer is restarted after the inter-UE physical feedback channel resource.

3 . The method of claim 1 , wherein, based on that the second inter-UE control information is related to the groupcast and the inter-UE HARQ feedback information is transmitted to the second device, the inter-UE DRX inactivity timer is restarted after the inter-UE physical feedback channel resource.

4 . The method of claim 1 ,

wherein the second inter-UE control information includes information representing whether an inter-UE HARQ feedback is enabled,

wherein the information representing whether the inter-UE HARQ feedback is enabled is set to HARQ feedback enabled, and

wherein the inter-UE HARQ feedback information is any one of negative acknowledge (NACK) information and positive acknowledge (ACK).

5 . The method of claim 1 , further comprising

stopping, by the first device, the started inter-UE DRX inactivity timer,

wherein, based on that the second inter-UE control information is related to the groupcast and the inter-UE DRX inactivity timer stops, the inter-UE DRX inactivity timer is restarted after the inter-UE physical feedback channel resource.

6 . The method of claim 1 , wherein, based on the restarting of the inter-UE DRX inactivity timer, at least one of the inter-UE DRX RTT timer or the inter-UE DRX retransmission timer is not started.

7 . The method of claim 1 , wherein, based on the restarting of the inter-UE DRX inactivity timer, the starting of at least one of the inter-UE DRX HARQ RTT timer or the inter-UE DRX retransmission timer is skipped.

8 . The method of claim 1 , wherein a length of the inter-UE DRX HARQ RTT timer is 0.

9 . The method of claim 1 , wherein, based on that the second inter-UE control information is related to the groupcast and the second inter-UE control information and the MAC PDU are received from the second device through the first inter-UE physical shared channel, the inter-UE DRX inactivity timer is started after the inter-UE physical feedback channel resource.

10 . The method of claim 1 , wherein the second inter-UE control information includes cast type information representing a NACK-ACK groupcast cast type.

11 . The method of claim 1 , wherein the inter-UE DRX inactivity timer is restarted after the inter-UE physical feedback channel resource, based on that the second inter-UE control information is related to the groupcast and based on the inter-UE HARQ feedback information to be transmitted last among a plurality of pieces of inter-UE HARQ feedback information to be transmitted to the second device.

12 . The method of claim 11 , wherein the inter-UE DRX inactivity timer is restarted after the inter-UE physical feedback channel resource, based on that the second inter-UE control information is related to the groupcast and based on the inter-UE HARQ feedback information to be transmitted last among a plurality of pieces of inter-UE HARQ feedback information to be transmitted to the second device within a running time of the inter-UE DRX inactivity timer.

13 . The method of claim 12 , wherein the first device is at least one device included in a first group which performs groupcast communication with respect to the second device, the method further comprising:

receiving, by the first device, third inter-UE control information for scheduling of a second inter-UE physical shared channel and fourth inter-UE control information from the second device through a second inter-UE physical shared channel, within a time during which the restarted inter-UE DRX inactivity timer is running and a time during which the inter-UE DRX inactivity timer of a third device is running; and

receiving, by the first device, the fourth inter-UE control information and a second MAC PDU from the second device through the second inter-UE physical shared channel, within the time during which the restarted inter-UE DRX inactivity timer is running and the time during which the inter-UE DRX inactivity timer of the third device is running.

14 . A processing device comprising:

at least one processor, and at least one memory connected to the at least one processor and storing instructions that, based on being executed by the at least one processor, cause a first device to perform operations comprising:

obtaining an inter-user equipment (inter-UE) link discontinuous reception (DRX) configuration including an inter-UE DRX inactivity timer, an inter-UE DRX hybrid automatic repeat request (HARQ) round-trip time (RTT) timer, and an inter-UE DRX retransmission timer;

receiving first inter-UE control information for scheduling of a first inter-UE physical shared channel and second inter-UE control information from a second device through a first inter-UE physical control channel;

receiving the second inter-UE control information and a first medium access control (MAC) protocol data unit (PDU) from the second device through the first inter-UE physical shared channel;

starting the inter-UE DRX inactivity timer;

transmitting inter-UE HARQ feedback information to the second device through an inter-UE physical feedback channel on an inter-UE physical feedback channel resource determined based on a slot index and a sub-channel index related to the first inter-UE physical shared channel; and

based on that the second inter-UE control information is related to groupcast, restarting the inter-UE DRX inactivity timer after the SCI is related to groupcast inter-UE physical feedback channel resource.

15 . The processing device of claim 14 , wherein, based on that the second inter-UE control information is related to the groupcast and the inter-UE DRX inactivity timer is running, the inter-UE DRX inactivity timer is restarted after the inter-UE physical feedback channel resource.

16 . The processing device of claim 15 , wherein, based on that the inter-UE control information is related to the groupcast and the inter-UE HARQ feedback information is transmitted to the second device, the inter-UE DRX inactivity timer is restarted after the inter-UE physical feedback channel resource.

17 . The processing device of claim 16 , wherein the second inter-UE control information includes information representing whether an inter-UE HARQ feedback is enabled,

wherein the information representing whether the inter-UE HARQ feedback is enabled is set to HARQ feedback enabled, and

wherein the inter-UE HARQ feedback information is any one of negative acknowledge (NACK) information and positive acknowledge (ACK).

18 . A method comprising:

obtaining, by a second device, an inter-user equipment (inter-UE) link discontinuous reception (DRX) configuration including an inter-UE DRX inactivity timer, an inter-UE DRX hybrid automatic repeat request (HARQ) round-trip time (RTT) timer, and an inter-UE DRX retransmission timer;

transmitting, by the second device, first inter-UE control information for scheduling of a first inter-UE physical shared channel and second inter-UE control information to a first device through a first inter-UE physical control channel;

transmitting, by the second device, the second inter-UE control information and a first medium access control (MAC) protocol data unit (PDU) to the first device through the first inter-UE physical shared channel;

starting, by the second device, the inter-UE DRX inactivity timer;

receiving, by the second device, inter-UE HARQ feedback information from the first device through an inter-UE physical feedback channel on an inter-UE physical feedback channel resource determined based on a slot index and a sub-channel index related to the first inter-UE physical shared channel; and

based on that the second inter-UE control information is related to groupcast, restarting, by the second device, the inter-UE DRX inactivity timer after the inter-UE physical feedback channel resource.

19 . The method of claim 18 , wherein, based on that the second inter-UE control information is related to the groupcast and the inter-UE HARQ feedback information is received from the first device, the inter-UE DRX inactivity timer is restarted after the inter-UE physical feedback channel resource.

20 . The method of claim 18 , wherein, based on that the second inter-UE control information is related to the groupcast and based on the inter-UE HARQ feedback information to be received last among a plurality of pieces of inter-UE HARQ feedback information to be received from the first device, the inter-UE DRX inactivity timer is restarted after the inter-UE physical feedback channel resource.