Method and device for performing sidelink communication in unlicensed band

A first device, comprising:

• at least one transceiver;
• 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 the first device to perform operations comprising:
• obtaining a plurality of SL resources including a first sidelink (SL) resource and a second SL resource;
• transmitting, through a physical sidelink control channel (PSCCH), first sidelink control information (SCI) for scheduling of a physical sidelink shared channel (PSSCH) and second SCI, based on the first SL resource;
• and
• transmitting, through the PSSCH, the second SCI including information related to a hybrid automatic repeat request (HARQ) process, and data, based on the first SL resource,
• wherein a period to which the first SL resource belongs is different from a period to which the second SL resource belongs, and
• wherein whether initial transmission or retransmission is allowed on the second SL resource is based on whether the plurality of SL resources are included in an unlicensed band and whether a timer is running.

A processing device adapted to control a first device, the 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 the first device to perform operations comprising:
• obtaining a plurality of SL resources including a first sidelink (SL) resource and a second SL resource;
• transmitting, through a physical sidelink control channel (PSCCH), first sidelink control information (SCI) for scheduling of a physical sidelink shared channel (PSSCH) and second SCI, based on the first SL resource;
• and
• transmitting, through the PSSCH, the second SCI including information related to a hybrid automatic repeat request (HARQ) process, and data, based on the first SL resource,
• wherein a period to which the first SL resource belongs is different from a period to which the second SL resource belongs, and
• wherein whether initial transmission or retransmission is allowed on the second SL resource is based on whether the plurality of SL resources are included in an unlicensed band and whether a timer is running.