Methods and apparatuses for determining nack-only based harq-ack codebook

A base station (BS) for wireless communication, comprising:

• at least one memory;
• and
• at least one processor coupled with the at least one memory and configured to cause the BS to:
• transmit, to a group of user equipments (UEs), a plurality of physical downlink shared channel (PDSCH) transmissions;
• receive, from one or multiple UEs of the group of UEs, one or multiple physical uplink control channel (PUCCH) transmissions on one or more PUCCH resources within a set of PUCCH resources, wherein each PUCCH transmission carries a hybrid automatic repeat request (HARQ) acknowledgement (ACK) feedback combination for the plurality of PDSCH transmissions;
• and
• determine each HARQ-ACK feedback combination based on the one or multiple PUCCH transmissions on the one or more PUCCH resources and a mapping table, wherein the mapping table defines relations between a set of HARQ-ACK feedback combinations and the set of PUCCH resources.

A method performed by a user equipment (UE), the method comprising:

• receiving a plurality of physical downlink shared channel (PDSCH) transmissions;
• determining a hybrid automatic repeat request (HARQ) acknowledgement (ACK) feedback combination including HARQ-ACK information bits for the plurality of PDSCH transmissions, wherein each HARQ-ACK information bit is associated with one of the plurality of PDSCH transmissions;
• determining a physical uplink control channel (PUCCH) resource based on the HARQ-ACK feedback combination in response to at least one PDSCH transmission of the plurality of PDSCH transmissions being incorrectly decoded;
• and
• performing a PUCCH transmission with the PUCCH resource.

A processor for wireless communication, comprising:

• at least one controller coupled with at least one memory and configured to cause the processor to:
• receive a plurality of physical downlink shared channel (PDSCH) transmissions;
• determine a hybrid automatic repeat request (HARQ) acknowledgement (ACK) feedback combination including HARQ-ACK information bits for the plurality of PDSCH transmissions, wherein each HARQ-ACK information bit is associated with one of the plurality of PDSCH transmissions;
• determine a physical uplink control channel (PUCCH) resource based on the HARQ-ACK feedback combination in response to at least one PDSCH transmission of the plurality of PDSCH transmissions being incorrectly decoded;
• and
• perform a PUCCH transmission with the PUCCH resource.