Method and apparatus for sidelink communication based on feedback

1. An operation method of a receiving terminal in sidelink communications, the operation method comprising:

receiving one or more transport blocks (TBs) from a transmitting terminal;

generating hybrid automatic repeat request (HARQ) responses for code block groups (CBGs) included in each of the one or more TBs;

selecting one or more HARQ responses from among the HARQ responses based on priorities;

identifying a CBG index associated with each of the one or more HARQ responses;

determining a physical sidelink feedback channel (PSFCH) resource based on the CBG index among a plurality of PSFCH resources; and

transmitting the one or more HARQ responses to the transmitting terminal through the PSFCH resource.

2. The operation method according to claim 1 , wherein the priorities are TB priorities, and when a plurality of TBs are received from the transmitting terminal, HARQ responses for CBGs included in a TB having a high priority among the plurality of TBs are preferentially selected.

3. The operation method according to claim 1 , wherein the priorities are CBG priorities, and a HARQ response for a CBG having a lower index among the CBGs is preferentially selected.

4. The operation method according to claim 1 , wherein the priorities are priorities of HARQ responses, and a HARQ response indicating an acknowledgment (ACK) among the HARQ responses is preferentially selected.

5. The operation method according to claim 1 , wherein a PSFCH format 1 for transmission of the one or more HARQ responses is configured, and the PSFCH resource is a resource for the PSFCH format 1.

6. The operation method according to claim 5 , wherein the PSFCH format 1 shares a same resource region with a PSFCH format 0 for transmission of one HARQ response, and a transmission resource of the PSFCH format 1 is indicated in a same manner as a transmission resource of the PSFCH format 0.

7. The operation method according to claim 5 , wherein a resource region of the PSFCH format 1 is configured independently from a resource region of a PSFCH format 0 for transmission of one HARQ response, and the resource region of the PSFCH format 1 is indicated by a higher layer message and/or sidelink control information (SCI).

8. The operation method according to claim 1 , wherein when a PSFCH format 0 and a PSFCH format 1 are configured, a PSFCH format used for transmission of the one or more HARQ responses is selected according to a preconfigured rule.

9. An operation method of a transmitting terminal in sidelink communications, the operation method comprising:

transmitting one or more transport blocks (TBs) to a receiving terminal through n subchannels;

receiving, from the receiving terminal, one or more hybrid automatic repeat request (HARQ) responses selected based on priorities from among HARQ responses for code block groups (CBGs) included in each of the one or more TBs through a physical sidelink feedback channel (PSFCH) resource; and

retransmitting a portion of the CBGs to the receiving terminal through m subchannels when retransmission is required for the portion of the CBGs among all CBGs included in the one or more TBs,

wherein each of n and m is a natural number.

10. The operation method according to claim 9 , wherein n is greater than m, a subchannel having a lower index among the n subchannels is preferentially selected, and the m subchannels selected among the n subchannels are used for retransmission of the portion of the CBGs.

11. The operation method according to claim 9 , wherein a first modulation and coding scheme (MCS) is used for transmission of the one or more TBs, a second MCS is used for retransmission of the portion of the CBGs, and an index of the second MCS is lower than an index of the first MCS.

12. The operation method according to claim 9 , wherein the priorities are TB priorities, and when a plurality of TBs are transmitted, HARQ responses for CBGs included in a TB having a high priority among the plurality of TB s are preferentially selected.

13. The operation method according to claim 9 , wherein the priorities are CBG priorities, and a HARQ response for a CBG having a lower index among the CBGs is preferentially selected.

14. The operation method according to claim 9 , wherein the priorities are priorities of HARQ responses, and a HARQ response indicating an acknowledgment (ACK) among the HARQ responses is preferentially selected.

15. The operation method according to claim 9 , further comprising transmitting a bitmap indicating the portion of the CBGs retransmitted among all the CBGs.

16. A receiving terminal in sidelink communications, the receiving terminal comprising:

a processor;

a memory electronically communicating with the processor; and

instructions stored in the memory,

wherein when executed by the processor, the instructions cause the receiving terminal to:

receive one or more transport blocks (TBs) from a transmitting terminal;

generate hybrid automatic repeat request (HARQ) responses for code block groups (CBGs) included in each of the one or more TBs;

select one or more HARQ responses from among the HARQ responses based on priorities;

identify a CBG index associated with each of the one or more HARQ responses;

determine a physical sidelink feedback channel (PSFCH) resource based on the CBG index among a plurality of PSFCH resources; and

transmit the one or more HARQ responses to the transmitting terminal through the PSFCH resource.

17. The receiving terminal according to claim 16 , wherein a PSFCH format 1 for transmission of the one or more HARQ responses is configured, the PSFCH format 1 shares a same resource region with a PSFCH format 0 for transmission of one HARQ response, and a transmission resource of the PSFCH format 1 is indicated in a same manner as a transmission resource of the PSFCH format 0.

18. The receiving terminal according to claim 16 , wherein a PSFCH format 1 for transmission of the one or more HARQ responses is configured, a resource region of the PSFCH format 1 is configured independently from a resource region of a PSFCH format 0 for transmission of one HARQ response, and the resource region of the PSFCH format 1 is indicated by a higher layer message and/or sidelink control information (SCI).