Channel access methods and listen-before-talk solutions for new radio operation in unlicensed bands

A base station, the base station comprising:

• a processor;
• a transceiver operatively coupled to the processor, the transceiver and processor configured to send a first physical downlink control channel (PDCCH) transmission, wherein the first PDCCH transmission includes configuration information, wherein the configuration information includes a first set of search spaces to be monitored at a first rate, a time period associated with a channel occupancy time (COT), and a second set of search spaces to be monitored at a second rate to be used at an expiration of the time period associated with the COT;
• and
• the transceiver and processor configured to send a second PDCCH transmission, wherein the second PDCCH is sent in the first set of search spaces on a condition that the time period associated with the COT has not expired, or to send a third PDCCH transmission in the second set of search spaces on a condition that the time period associated with the COT has expired.

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

• receiving a first physical downlink control channel (PDCCH) transmission, wherein the first PDCCH transmission includes configuration information, wherein the configuration information includes a first set of search spaces to be monitored at a first rate, a time period associated with a channel occupancy time (COT), and a second set of search spaces to be monitored at a second rate to be used after an expiration of the time period associated with the COT;
• monitoring for a second PDCCH transmission in the first set of search spaces at the first rate on a condition the time period associated with the COT has not expired;
• and
• monitoring for a second scheduling transmission on the PDCCH in the second set of search spaces at the second rate on a condition that the time period associated with the COT has expired.

A wireless transmit receive unit (WTRU), comprising:

• a processor;
• a transceiver operatively coupled to the processor,
• the transceiver and processor are configured to receive a first physical downlink control channel (PDCCH) transmission, wherein the first PDCCH transmission includes configuration information, wherein the configuration information includes a first set of search spaces to be monitored at a first rate, a time period associated with a channel occupancy time (COT), and a second set of search spaces to be monitored at a second rate to be used after an expiration of the time period associated with the COT;
• the transceiver and processor configured to monitor for second PDCCH transmission in the first set of search spaces at the first rate on a condition the time period associated with the COT has not expired;
• and
• the transceiver and processor configured to monitor for a third PDCCH transmission in the second set of search spaces at the second rate on a condition that the time period associated with the COT has expired.