# US 12,120,742 B2 · Channel access methods and listen-before-talk solutions for new radio operation in unlicensed bands > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,120,742 B2 - Document ID: US12120742B2 - Status: Granted - Kind: B2 - Application number: 18/092,684 - Filed: 2023-01-03 - Published: 2023-07-20 - Granted: 2024-10-15 - Earliest claimed: 2018-01-10 - Assignees: InterDigital Patent Holdings, Inc. - Applicants: Interdigital Patent Holdings, Inc. - Inventors: Ahmad Reza Hedayat; Oghenekome Oteri; Hanqing Lou; Mahmoud Taherzadeh Boroujeni; Xiaofei Wang; Rui Yang; Shahrokh Nayeb Nazar - Web page: https://patentgrep.com/patent/US12120742B2 ## CPC - H04W 74/0816: with collision avoidance - H04L 5/005: {of common pilots, i.e. pilots destined for multiple users or terminals} - H04L 5/0053: {Allocation of signalling, i.e. of overhead other than pilot signals} - H04L 5/0082: {at predetermined intervals} - H04L 5/0091: {Signalling for the administration of the divided path, e.g. signalling of configuration information} - H04W 52/34: TPC management, i.e. sharing limited amount of power among users or channels or data types, e.g. cell loading - H04W 72/0446: Resources in time domain, e.g. slots or frames - H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal - H04L 5/0064: {Rate requirement of the data, e.g. scalable bandwidth, data priority} - H04W 16/14: Spectrum sharing arrangements {between different networks} - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Methods, systems, and devices for channel access and listen-before-talk approaches for new radio operation in unlicensed bands and/or licensed bands. A gNB and a wireless transmit/receive unit (WTRU) may operate in unlicensed spectrum. The gNB may perform listen-before-talk operation, and when successful, may send a downlink control channel with a slot format indication (SFI) to the WTRU. There may also be a handshaking procedure with an exchange of a request to transmit (RTT) and a request to receive (RTR). Prior to receiving the downlink channel, the WTRU may monitor search spaces at a first level, and once the downlink channel is received the WTRU may monitor search spaces at a second level. At the end of transmission, the WTRU may revert back to monitoring search spaces at the first level. In one example, the first level may be a mini-slot level and the second level may be a slot level. ## Claims ### Claim 1 A method implemented by a base station, the method comprising: sending 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 sending a second PDCCH transmission in the first set of search spaces after sending the configuration information on a condition that the time period associated with the COT has not expired, or sending a third PDCCH transmission in the second set of search spaces on a condition that the time period associated with the COT has expired. ### Claim 2 (depends on 1) The method of claim 1, wherein the first PDCCH transmission further includes a first slot format indicator (SFI) and a second SFI, or wherein the second PDCCH transmission is sent after the first PDCCH transmission is sent. ### Claim 3 (depends on 1) The method of claim 1, wherein the time period is a time remaining in the COT. ### Claim 4 (depends on 1) The method of claim 1, wherein the base station is a gNB. ### Claim 5 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. ### Claim 6 (depends on 5) The base station of claim 5, wherein the first transmission further includes a first slot format indicator (SFI) and a second SFI, or wherein the second PDCCH transmission is sent after the first PDCCH transmission is sent. ### Claim 7 (depends on 5) The base station of claim 5, wherein the time period is a time remaining in the COT. ### Claim 8 (depends on 5) The base station of claim 5, wherein the base station is a gNB. ### Claim 9 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. ### Claim 10 (depends on 9) The method of claim 9, wherein the configuration information further includes a first slot format indicator. ### Claim 11 (depends on 10) The method of claim 10, wherein the monitoring for the second PDCCH transmission is based on the first slot format indicator. ### Claim 12 (depends on 9) The method of claim 9, wherein the configuration information further includes a second slot format indicator. ### Claim 13 (depends on 12) The method of claim 12, wherein a monitoring for a third PDCCH transmission is based on the second slot format indicator. ### Claim 14 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. ### Claim 15 (depends on 14) The WTRU of claim 14, wherein the configuration information further includes a first slot format indicator. ### Claim 16 (depends on 15) The WTRU of claim 15, wherein the monitoring for the second PDCCH transmission is based on the first slot format indicator. ### Claim 17 (depends on 14) The WTRU of claim 14, wherein the configuration information further includes a second slot format indicator. ### Claim 18 (depends on 17) The WTRU of claim 17, wherein a monitoring for a third PDCCH transmission based on the second slot format indicator.