Contention window size adjustment procedure for sidelink groupcast

A method, comprising:

• transmitting physical shared control channel (“PSCCH”) and physical shared sidelink channel (“PSSCH”) corresponding to groupcast data transmission;
• receiving physical shared feedback channel (“PSFCH”) containing hybrid automatic repeat request (“HARQ”) feedback after a predetermined number of slots for a corresponding groupcast transmission;
• and
• determining a contention window size adjustment for a groupcast PSSCH based on the transmitted groupcast HARQ feedback associated with PSSCH within a reference duration.

An apparatus, comprising:

• a processor;
• and
• a memory coupled to the processor, the processor configured to cause the apparatus to:
• receive physical shared control channel (“PSCCH”) and physical shared sidelink channel (“PSSCH”) corresponding to groupcast data transmission;
• and
• transmit physical shared feedback channel (“PSFCH”) containing hybrid automatic repeat request (“HARQ”) feedback after a predetermined number of slots for a corresponding groupcast transmission for determining a contention window size adjustment for a groupcast PSSCH based on the transmitted groupcast HARQ feedback associated with PSSCH within a reference duration.