Harq process for sidelink transmission

An apparatus for wireless communication, the apparatus comprising:

• a processor;
• and
• a memory coupled to the processor, wherein the processor is configured to cause the apparatus to:
• receive a sidelink (“SL”) grant for a SL transmission using SL resources, the SL grant indicating a first hybrid automatic repeat request (“HARQ”) process identified by a first HARQ process identifier;
• select a second SL HARQ process identified by a second SL HARQ process identifier for the SL transmission using the SL resources,
• wherein the second SL HARQ process is selected independently from the first HARQ process in response to the SL grant indicating an SL initial transmission, and
• wherein the selection of the second SL HARQ process is based on the first HARQ process identifier in response to the SL grant indicating a SL retransmission;
• transmit SL control information (“SCI”) containing the second SL HARQ process identifier;
• and
• perform the SL transmission using the SL resources.