# US 11,122,565 B2 · Listen-before-talk procedures for transmit opportunity (TXOP) > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,122,565 B2 - Document ID: US11122565B2 - Status: Granted - Kind: B2 - Application number: 16/711,950 - Filed: 2019-12-12 - Published: 2020-04-16 - Granted: 2021-09-14 - Earliest claimed: 2017-02-08 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Farouk Belghoul; Christian W. Mucke; Awais M. Hussain - Web page: https://patentgrep.com/patent/US11122565B2 ## CPC - H04W 72/0446: Resources in time domain, e.g. slots or frames - H04L 1/1854: {Scheduling and prioritising arrangements} - H04L 5/1469: {using time-sharing} - H04W 72/1215: {for collaboration of different radio technologies} - H04W 72/1268: of uplink data flows - H04W 72/1273: of downlink data flows - H04W 74/006: {in the downlink, i.e. towards the terminal} - H04W 74/0808: using carrier sensing, e.g. carrier sense multiple access [CSMA] - H04W 74/0816: with collision avoidance - H04L 5/0055: {Physical resource allocation for ACK/NACK (for physical mapping arrangements in ARQ protocols H04L1/1861)} - H04W 72/0453: Resources in frequency domain, e.g. a carrier in FDMA - H04W 72/12: Wireless traffic scheduling - 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 This disclosure relates to performing cellular communication in unlicensed spectrum using a flexible slot structure. A cellular base station may perform a listen-before-talk procedure, and may transmit a reservation frame when the listen-before-talk procedure is successful. The reservation frame may reserve a wireless medium for a transmit opportunity. Transmission slots may be scheduled for communication with one or more wireless devices during the transmit opportunity. The transmission slots may be selected from multiple possible uplink transmission slot types and multiple possible downlink transmission slot types. Indications of the scheduled transmission slots, including indications of slot types of the scheduled transmission slots, may be provided to the wireless devices. Wireless communication may be performed between the cellular base station and the wireless devices according to the scheduled transmission slots. ## Claims ### Claim 1 An apparatus, comprising: a processor configured to cause a wireless device to: receive a reservation frame from a cellular base station, wherein the reservation frame indicates a length, wherein the reservation frame reserves a wireless medium for a transmit opportunity (TXOP) of the indicated length; determine whether a scheduled uplink transmission in the TXOP extends beyond the TXOP; and select a type of listen-before-talk procedure, from a plurality of possible types of listen-before-talk procedures, to perform prior to the scheduled uplink transmission in the TXOP, wherein the type of listen-before-talk procedure is selected from the plurality of possible types of listen-before-talk procedures based at least in part on the determination of whether the scheduled uplink transmission in the TXOP extends beyond the TXOP, wherein a first type of listen-before-talk procedure of the plurality of possible types of listen-before-talk procedures includes a short listen-before-talk procedure, and wherein the plurality of possible types of listen-before-talk procedures further includes a second type of listen-before-talk procedure different from the first type of listen-before-talk procedure. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the processor is further configured to cause the wireless device to transmit a Wi-Fi preamble before the uplink transmission. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein transmission slot types are dynamically selected based at least in part on one or more of: a remaining time of the TXOP; or an amount of uplink and/or downlink data buffered for communication between the cellular base station and the wireless device. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the processor is further configured to cause the wireless device to: perform the selected type of listen-before-talk procedure on unlicensed spectrum, wherein the unlicensed spectrum includes one of: a standalone fifth generation (5G) new radio (NR) carrier; a 5G NR carrier providing dual connectivity in conjunction with a long term evolution (LTE) carrier operating in licensed spectrum; or a 5G NR carrier provided as a secondary carrier as part of a carrier aggregation scheme in conjunction with a 5G NR carrier operating in licensed spectrum. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the first type of listen-before-talk procedure is selected in response to a determination that an uplink symbol is within a remaining time of the TXOP. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the second type of listen-before-talk procedure includes transmitting a second reservation frame. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the second type of listen-before-talk procedure is selected in response to a determination that an uplink symbol is not within the remaining time of the TXOP. ### Claim 8 A wireless device, comprising: a radio; and a processor operably connected to the radio and configured to cause the wireless device to: receive a reservation frame from a cellular base station, wherein the reservation frame indicates a length, wherein the reservation frame reserves a wireless medium for a transmit opportunity (TXOP) of the indicated length; determine whether a scheduled uplink transmission in the TXOP extends beyond the TXOP; and select a type of listen-before-talk procedure, from a plurality of possible types of listen-before-talk procedures, to perform prior to the scheduled uplink transmission in the TXOP, wherein the type of listen-before-talk procedure is selected from the plurality of possible types of listen-before-talk procedures based at least in part on the determination of whether the scheduled uplink transmission in the TXOP extends beyond the TXOP, wherein a first type of listen-before-talk procedure of the plurality of possible types of listen-before-talk procedures includes a short listen-before-talk procedure, and wherein the plurality of possible types of listen-before-talk procedures further includes a second type of listen-before-talk procedure different from the first type of listen-before-talk procedure. ### Claim 9 (depends on 8) The wireless device of claim 8, wherein the processor is further configured to cause the wireless device to transmit a second reservation frame before the uplink transmission. ### Claim 10 (depends on 8) The wireless device of claim 8, wherein transmission slot types are dynamically selected based at least in part on one or more of: a remaining time of the TXOP; or an amount of uplink and/or downlink data buffered for communication between the cellular base station and the wireless device. ### Claim 11 (depends on 8) The wireless device of claim 8, wherein the processor is further configured to cause the wireless device to: perform the selected type of listen-before-talk procedure on unlicensed spectrum, wherein the unlicensed spectrum includes one of: a standalone fifth generation (5G) new radio (NR) carrier; a 5G NR carrier providing dual connectivity in conjunction with a long term evolution (LTE) carrier operating in licensed spectrum; or a 5G NR carrier provided as a secondary carrier as part of a carrier aggregation scheme in conjunction with a 5G NR carrier operating in licensed spectrum. ### Claim 12 (depends on 8) The wireless device of claim 8, wherein the first type of listen-before-talk procedure is selected in response to a determination that an uplink symbol is within a remaining time of the TXOP. ### Claim 13 (depends on 8) The wireless device of claim 8, wherein the second type of listen-before-talk procedure includes transmitting a Wi-Fi preamble. ### Claim 14 (depends on 8) The wireless device of claim 8, wherein the second type of listen-before-talk procedure is selected in response to a determination that an uplink symbol is not within the remaining time of the TXOP. ### Claim 15 A method for operating a wireless device, the method comprising: at the wireless device: receiving a reservation frame from a cellular base station, wherein the reservation frame indicates a length, wherein the reservation frame reserves a wireless medium for a transmit opportunity (TXOP) of the indicated length; determine whether a scheduled uplink transmission in the TXOP extends beyond the TXOP; and selecting a type of listen-before-talk procedure, from a plurality of possible types of listen-before-talk procedures, to perform prior to the scheduled uplink transmission in the TXOP, wherein the type of listen-before-talk procedure is selected from the plurality of possible types of listen-before-talk procedures based at least in part on the determination of whether the scheduled uplink transmission in the TXOP extends beyond the TXOP, wherein a first type of listen-before-talk procedure of the plurality of possible types of listen-before-talk procedures includes a short listen-before-talk procedure, and wherein the plurality of possible types of listen-before-talk procedures further includes a second type of listen-before-talk procedure different from the first type of listen-before-talk procedure. ### Claim 16 (depends on 15) The method of claim 15, wherein transmission slot types are dynamically selected based at least in part on one or more of: a remaining time of the TXOP; or an amount of uplink and/or downlink data buffered for communication between the cellular base station and the wireless device. ### Claim 17 (depends on 15) The method of claim 15, further comprising performing the selected type of listen-before-talk procedure on unlicensed spectrum, wherein the unlicensed spectrum includes one of: a standalone fifth generation (5G) new radio (NR) carrier; a 5G NR carrier providing dual connectivity in conjunction with a long term evolution (LTE) carrier operating in licensed spectrum; or a 5G NR carrier provided as a secondary carrier as part of a carrier aggregation scheme in conjunction with a 5G NR carrier operating in licensed spectrum. ### Claim 18 (depends on 15) The method of claim 15, wherein the first type of listen-before-talk procedure is selected in response to a determination that an uplink symbol is within a remaining time of the TXOP. ### Claim 19 (depends on 15) The method of claim 15, wherein the second type of listen-before-talk procedure includes transmitting a second reservation frame. ### Claim 20 (depends on 15) The method of claim 15, wherein the second type of listen-before-talk procedure is selected in response to a determination that an uplink symbol is not within the remaining time of the TXOP.