Efficient and robust acknowledgement procedures for new radio operation in unlicensed bands

A method implemented by a wireless transmit receive unit (WTRU), the method comprising:

• receiving first control information for a first physical downlink shared channel (PDSCH) transmission on a first physical downlink control channel (PDCCH), and wherein the first control information further includes a first HARQ feedback timing indicator;
• determining not to send a first HARQ feedback for the first PDSCH transmission based on a value of the first HARQ feedback timing indicator;
• receiving second control information for a second PDSCH transmission on a second PDCCH;
• and
• sending HARQ feedback that includes the first HARQ feedback for the first PDSCH transmission combined with a second HARQ feedback for the second PDSCH transmission based on the second control information.

A wireless transmit receive unit (WTRU), the WTRU comprising:

• a processor operatively coupled to a transceiver;
• the transceiver configured to receive first control information for a first physical downlink shared channel (PDSCH) transmission on a first physical downlink control channel (PDCCH), and wherein the first control information further includes a first HARQ feedback timing indicator;
• the processor configured to determine not to send a first HARQ feedback for the first PDSCH transmission based on a value of the first HARQ feedback timing indicator;
• the transceiver configured to receive second control information for a second PDSCH transmission on a second PDCCH;
• and
• the transceiver configured to send HARQ feedback that includes the first HARQ feedback for the first PDSCH transmission combined with a second HARQ feedback for the second PDSCH transmission based on the second control information.