Method and apparatus for generating device-to-device sidelink HARQ-ACK in a wireless communication system

A method of a first User Equipment (UE) for transmitting a sidelink Hybrid Automatic Repeat Request acknowledgement (HARQ-ACK) codebook to a network in a third slot, the method comprising:

• receiving, from the network, a first configuration with a set of time offsets for determining an association set, wherein:
• the association set comprises a set of slots determined based upon the set of time offsets;
• and
• the set of slots is earlier than the third slot;
• receiving, from the network, a second configuration with a plurality of sidelink resource pools in at least one of a carrier or a cell, wherein:
• the plurality of sidelink resource pools comprises a first sidelink resource pool and a second sidelink resource pool;
• Physical Sidelink Feedback Channel (PSFCH) resources of the first sidelink resource pool are configured, periodically with a period of N1 slots, in slots of the first sidelink resource pool;
• and
• PSFCH resources of the second sidelink resource pool are configured, periodically with a period of N2 slots, in slots of the second sidelink resource pool;
• determining one or more first slots, wherein each slot of the one or more first slots is in the association set and each slot of the one or more first slots comprises at least one of the PSFCH resources of the first sidelink resource pool;
• determining one or more second slots, wherein each slot of the one or more second slots is in the association set and each slot of the one or more second slots comprises at least one of the PSFCH resources of the second sidelink resource pool;
• and
• generating the sidelink HARQ-ACK codebook based upon one or more first occasions and one or more second occasions, wherein:
• the one or more first occasions is determined or derived based upon the one or more first slots and the period of N1 slots;
• and
• the one or more second occasions is determined or derived based upon the one or more second slots and the period of N2 slots.

A method of a first User Equipment (UE) for transmitting a sidelink Hybrid Automatic Repeat Request acknowledgement (HARQ-ACK) codebook to a network in a third slot, the method comprising:

• receiving, from the network, a configuration of a sidelink resource pool in at least one of a carrier or a cell, wherein:
• Physical Sidelink Feedback Channel (PSFCH) resources of the sidelink resource pool are configured, periodically with a period of N slots, in slots of the sidelink resource pool;
• and
• N is larger than 1;
• receiving, from the network, a configuration with a set of time offsets for determining an association set, wherein:
• the association set comprises a set of slots of the sidelink resource pool;
• the set of slots is earlier than the third slot;
• and
• the set of slots is determined based upon the set of time offsets;
• determining one or more first slots, wherein each slot of the one or more first slots is in the association set and each slot of the one or more first slots comprises at least one of the PSFCH resources of the sidelink resource pool;
• and
• generating the sidelink HARQ-ACK codebook based upon one or more first occasions and an order of the one or more first occasions, wherein the one or more first occasions is determined or derived based upon the one or more first slots and the period of N slots, and wherein:
• the one or more first occasions comprise a plurality of sets of occasions;
• the order of the one or more first occasions corresponds to a first set of occasions of the plurality of sets of occasions being followed by a second set of occasions of the plurality of sets of occasions;
• the first set of occasions is associated with a first set of PSFCH resources in an earliest slot of the one or more first slots;
• and
• the second set of occasions is associated with a second set of PSFCH resources in a slot, of the one or more first slots, after the earliest slot of the one or more first slots.