# US 2021/0243800 A1 · Synchronous channel access based on adaptive channel occupancy time management > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0243800 A1 - Document ID: US20210243800A1 - Status: Published application - Kind: A1 - Application number: 16/953,097 - Filed: 2020-11-19 - Published: 2021-08-05 - Earliest claimed: 2020-01-30 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Yisheng XUE; Aleksandar DAMNJANOVIC; Xiaoxia ZHANG; Yongbin WEI - Web page: https://patentgrep.com/patent/US20210243800A1 ## CPC - H04W 74/002: {Transmission of channel access control information} - H04W 74/0808: using carrier sensing, e.g. carrier sense multiple access [CSMA] - H04W 16/14: Spectrum sharing arrangements {between different networks} - H04W 74/0816: with collision avoidance - H04W 74/0891: {for synchronized access} - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a node may identify a listen-before-talk (LBT) success time at which an LBT procedure, performed by the node, succeeds; determine a lag between the LBT success time and a most recent synchronization reference boundary that occurred prior to the LBT success time; and determine a maximum channel occupancy time for transmissions on an unlicensed radio frequency spectrum band based at least in part on comparing the lag and a threshold. Numerous other aspects are provided. ## Claims ### Claim 1 A method of wireless communication performed by a node, comprising: identifying a listen-before-talk (LBT) success time at which an LBT procedure, performed by the node, succeeds; determining a lag between the LBT success time and a most recent synchronization reference boundary that occurred prior to the LBT success time; and determining a maximum channel occupancy time (MCOT) for transmissions on an unlicensed radio frequency spectrum band based at least in part on comparing the lag and a threshold. ### Claim 2 (depends on 1) The method of claim 1, further comprising transmitting on the unlicensed radio frequency spectrum band during a time interval defined by the LBT success time and the MCOT. ### Claim 3 (depends on 1) The method of claim 1, wherein if the lag satisfies the threshold, the MCOT comprises a time period that terminates at a first synchronization reference boundary occurring after the LBT success time. ### Claim 4 (depends on 1) The method of claim 1, wherein if the lag does not satisfy the threshold, the MCOT comprises a time period that terminates at a second synchronization reference boundary occurring after the LBT success time. ### Claim 5 (depends on 1) The method of claim 1, wherein the threshold is fixed. ### Claim 6 (depends on 1) The method of claim 1, wherein the threshold is variable. ### Claim 7 (depends on 6) The method of claim 6, wherein the threshold comprises an initial threshold value, a modified threshold value, or a combination thereof, wherein the node determines the modified threshold value based at least in part on the initial threshold value and an adaptive control procedure. ### Claim 8 (depends on 1) The method of claim 1, further comprising: receiving, from another node, a threshold mode indication that indicates a threshold mode, of a plurality of threshold modes, to be used for determining the threshold, the plurality of threshold modes comprising a fixed threshold mode in which the threshold is fixed and a variable threshold mode in which the threshold is variable, wherein the indicated threshold mode comprises the variable threshold mode; dynamically modifying a value of the threshold based at least in part on an adaptive control procedure associated with a target MCOT; and operating according to the indicated threshold mode. ### Claim 9 (depends on 1) The method of claim 1, further comprising: determining an estimated average MCOT; comparing the estimated average MCOT and a target MCOT; and determining a modified threshold by modifying an initial threshold based at least in part on comparing the estimated average MCOT and the target MCOT. ### Claim 10 (depends on 9) The method of claim 9, wherein determining the modified threshold comprises: increasing the initial threshold by an upward step size if the estimated average MCOT is greater than the target MCOT; or decreasing the initial threshold by a downward step size if the estimated average MCOT is less than the target MCOT. ### Claim 11 A method of wireless communication performed by a node, comprising: generating a random number associated with determining a maximum channel occupancy time (MCOT) for a transmission on an unlicensed radio frequency spectrum band; comparing the random number and a threshold; and determining the MCOT based at least in part on comparing the random number and the threshold. ### Claim 12 (depends on 11) The method of claim 11, further comprising transmitting on the unlicensed radio frequency spectrum band during a time interval defined by a listen-before-talk (LBT) success time and the MCOT. ### Claim 13 (depends on 11) The method of claim 11, wherein if the random number satisfies the threshold, the MCOT comprises a time period that terminates at a first synchronization reference boundary occurring after a listen-before-talk (LBT) success time. ### Claim 14 (depends on 11) The method of claim 11, wherein if the random number does not satisfy the threshold, the MCOT comprises a time period that terminates at a second synchronization reference boundary occurring after a listen-before-talk (LBT) success time. ### Claim 15 (depends on 11) The method of claim 11, wherein the threshold is variable. ### Claim 16 (depends on 15) The method of claim 15, wherein the threshold comprises an initial threshold value, a modified threshold value, or a combination thereof, wherein the node determines the modified threshold value based at least in part on the initial threshold value and an adaptive control procedure. ### Claim 17 (depends on 11) The method of claim 11, further comprising: receiving, from another node, a threshold mode indication that indicates a threshold mode, of a plurality of threshold modes, to be used for determining the threshold, the plurality of threshold modes comprising a fixed threshold mode in which the threshold is fixed and a variable threshold mode in which the threshold is variable, wherein the indicated threshold mode comprises the variable threshold mode; dynamically modifying a value of the threshold based at least in part on an adaptive control procedure associated with a target MCOT; and operating according to the indicated threshold mode. ### Claim 18 (depends on 11) The method of claim 11, further comprising: determining an estimated average MCOT; comparing the estimated average MCOT and a target MCOT; and determining a modified threshold by modifying an initial threshold based at least in part on comparing the estimated average MCOT and the target MCOT. ### Claim 19 (depends on 18) The method of claim 18, wherein determining the modified threshold comprises: increasing the initial threshold by an upward step size if the estimated average MCOT is greater than the target MCOT; or decreasing the initial threshold by a downward step size if the estimated average MCOT is less than the target MCOT. ### Claim 20 A node for wireless communication, comprising: a memory; and one or more processors operatively coupled to the memory, the memory and the one or more processors configured to: identify a listen-before-talk (LBT) success time at which an LBT procedure, performed by the node, succeeds; determine a lag between the LBT success time and a most recent synchronization reference boundary that occurred prior to the LBT success time; and determine a maximum channel occupancy time (MCOT) for transmissions on an unlicensed radio frequency spectrum band based at least in part on comparing the lag and a threshold. ### Claim 21 (depends on 20) The node of claim 20, the memory and the one or more processors further configured to transmit on the unlicensed radio frequency spectrum band during a time interval defined by the LBT success time and the MCOT. ### Claim 22 (depends on 20) The node of claim 20, wherein if the lag satisfies the threshold, the MCOT comprises a time period that terminates at a first synchronization reference boundary occurring after the LBT success time. ### Claim 23 (depends on 20) The node of claim 20, wherein if the lag does not satisfy the threshold, the MCOT comprises a time period that terminates at a second synchronization reference boundary occurring after the LBT success time. ### Claim 24 (depends on 20) The node of claim 20, the memory and the one or more processors further configured to receive, from another node, an indication of a set of parameters that indicate: a plurality of synchronization reference boundaries, a synchronization interval, the threshold, or a combination thereof. ### Claim 25 (depends on 20) The node of claim 20, wherein the threshold is variable. ### Claim 26 (depends on 25) The node of claim 25, wherein the threshold comprises an initial threshold value, a modified threshold value, or a combination thereof, wherein the node determines the modified threshold value based at least in part on the initial threshold value and an adaptive control procedure. ### Claim 27 (depends on 20) The node of claim 20, the memory and the one or more processors further configured to: receive, from another node, a threshold mode indication that indicates a threshold mode, of a plurality of threshold modes, to be used for determining the threshold, the plurality of threshold modes comprising a fixed threshold mode in which the threshold is fixed and a variable threshold mode in which the threshold is variable, wherein the indicated threshold mode comprises the variable threshold mode; modify a value of the threshold based at least in part on an adaptive control procedure associated with a target MCOT; and operate according to the indicated threshold mode. ### Claim 28 (depends on 27) The node of claim 27, the memory and the one or more processors further configured to: determine an estimated average MCOT; compare the estimated average MCOT and a target MCOT; and determine a modified threshold by modifying an initial threshold based at least in part on comparing the estimated average MCOT and the target MCOT. ### Claim 29 (depends on 28) The node of claim 28, wherein determining the modified threshold comprises: increasing the initial threshold by an upward step size if the estimated average MCOT is greater than the target MCOT; or decreasing the initial threshold by a downward step size if the estimated average MCOT is less than the target MCOT. ### Claim 30 A node for wireless communication, comprising: a memory; and one or more processors operatively coupled to the memory, the memory and the one or more processors configured to: generate a random number associated with determining a maximum channel occupancy time (MCOT) for a transmission on an unlicensed radio frequency spectrum band; compare the random number and a threshold; and determine the MCOT based at least in part on comparing the random number and the threshold.