# US 11,115,170 B2 · Techniques for adjusting clear channel assessment (CCA) window for transmissions in a shared radio frequency spectrum band > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,115,170 B2 - Document ID: US11115170B2 - Status: Granted - Kind: B2 - Application number: 16/266,878 - Filed: 2019-02-04 - Published: 2019-06-20 - Granted: 2021-09-07 - Earliest claimed: 2015-05-23 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM incorporated - Inventors: Srinivas Yerramalli; Tao Luo; Aleksandar Damnjanovic; Peter Gaal; Ravi Teja Sukhavasi; Xiaoxia Zhang - Web page: https://patentgrep.com/patent/US11115170B2 ## CPC - H04L 5/0055: {Physical resource allocation for ACK/NACK (for physical mapping arrangements in ARQ protocols H04L1/1861)} - H04L 1/1657: {Implicit acknowledgement of correct or incorrect reception, e.g. with a moving window} - H04L 1/1812: Hybrid protocols; Hybrid automatic repeat request [HARQ] - H04L 1/1822: involving configuration of automatic repeat request [ARQ] with parallel processes - H04L 1/187: {Details of sliding window management} - H04W 4/06: Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services - H04W 72/0453: Resources in frequency domain, e.g. a carrier in FDMA - H04W 72/21: in the uplink direction of a wireless link, i.e. towards the network - H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal - H04W 74/08: Non-scheduled access, e.g. ALOHA (hybrid access H04W74/02) - H04W 74/0808: using carrier sensing, e.g. carrier sense multiple access [CSMA] - H04W 76/28: Discontinuous transmission [DTX]; Discontinuous reception [DRX] - H04W 16/14: Spectrum sharing arrangements {between different networks} - H04W 72/20: Control channels or signalling for resource management - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Techniques and devices are described for wireless communication. A base station may determine a parameter associated with a transmission such as hybrid automatic repeat request (HARQ) feedback, a signal-to-noise ratio, or a determination regarding whether the transmission was successfully decoded. The base station may then determine a contention window adjustment value based on the parameter. The base station may then apply weighting factor (e.g., based on the time of the transmission, a number of devices being served, aspects of the transmission parameter, etc.) to the contention window adjustment value may adjust a contention window size for a second transmission based on the weighted contention window adjustment value (and, in some cases, other weighted adjustments based on other transmissions). The base station may then perform a clear channel assessment (CCA) based on the contention window size. ## Claims ### Claim 1 A method for wireless communications comprising: determining a feedback parameter associated with a first transmission; determining a contention window adjustment value based at least in part on the feedback parameter, wherein determining the contention window adjustment value comprises weighting a non-reported acknowledgement as a reported negative acknowledgment (NACK); and adjusting a contention window size for a second transmission based at least in part on the contention window adjustment value. ### Claim 2 (depends on 1) The method of claim 1, wherein determining the contention window adjustment value comprises weighting a HARQ feedback based at least in part on whether the HARQ feedback is in a multiplexed mode. ### Claim 3 (depends on 1) The method of claim 1, wherein determining the contention window adjustment value comprises weighting an identified discontinuous transmission (DTX) as a reported negative acknowledgment (NACK). ### Claim 4 (depends on 1) The method of claim 1, wherein: determining the contention window adjustment value is based at least in part on feedback parameters for a plurality of carriers; and adjusting the contention window size comprises adjusting the contention window size for all of the plurality of carriers. ### Claim 5 (depends on 1) The method of claim 1, wherein the feedback parameter comprises hybrid automatic repeat request (HARQ) feedback for one or more transmission opportunities. ### Claim 6 (depends on 5) The method of claim 5, wherein determining the contention window adjustment value is based at least in part on a number of negative acknowledgement (NACKs) in the HARQ feedback. ### Claim 7 (depends on 1) The method of claim 1, wherein determining the feedback parameter comprises: determining whether a physical uplink control channel (PUCCH) has been successfully decoded. ### Claim 8 (depends on 1) The method of claim 1, wherein the contention window size corresponds to a transmission opportunity, and the contention window size is adjusted based at least in part on whether the transmission opportunity is self-scheduled or cross-carrier scheduled. ### Claim 9 (depends on 1) The method of claim 1, further comprising: transmitting the first transmission over one or more carriers. ### Claim 10 (depends on 9) The method of claim 9, wherein the first transmission is transmitted over a plurality of carriers, the method further comprising: determining a different contention window size for each of the plurality of carriers. ### Claim 11 (depends on 9) The method of claim 9, wherein the first transmission is transmitted over a plurality of carriers, the method further comprising: receiving a number of negative acknowledgements (NACKs) through hybrid automatic repeat request (HARQ) feedback for each of the plurality of carriers; and adjusting the contention window size for the second transmission for all of the plurality of carriers based at least in part on the number of NACKs for all of the plurality of carriers, wherein the contention window size is the same for all of the plurality of carriers. ### Claim 12 (depends on 9) The method of claim 9, wherein the one or more carriers comprise a primary carrier and one or more secondary carriers, the method further comprising: starting a backoff timer associated with the primary carrier, wherein the backoff timer applies to the one or more secondary carriers. ### Claim 13 (depends on 1) The method of claim 1, further comprising: performing a clear channel assessment based at least in part on the contention window size. ### Claim 14 (depends on 1) The method of claim 1, further comprising: transmitting the second transmission on a carrier that is different from a carrier of the first transmission; and refraining from resetting the contention window size. ### Claim 15 (depends on 1) The method of claim 1, wherein the first transmission is sent to one or more UEs, the method further comprising: resetting the contention window size. ### Claim 16 (depends on 1) The method of claim 1, wherein the feedback parameter comprises an interference indication received in a PUCCH. ### Claim 17 (depends on 1) The method of claim 1, wherein the contention widow size corresponds to a DL transmission opportunity following one or more DL transmission opportunities corresponding to the feedback parameter. ### Claim 18 An apparatus for wireless communications, comprising: a processor; memory coupled to the processor; and the processor and memory configured to: determine a feedback parameter associated with a first transmission; determine a contention window adjustment value based at least in part on the feedback parameter, wherein determining the contention window adjustment value comprises weighting a non-reported acknowledgement as a reported negative acknowledgment (NACK); and adjust a contention window size for a second transmission based at least in part on the contention window adjustment value. ### Claim 19 (depends on 18) The apparatus of claim 18, wherein determining the contention window adjustment value comprises weighting a HARQ feedback based at least in part on whether the HARQ feedback is in a multiplexed mode. ### Claim 20 (depends on 18) The apparatus of claim 18, wherein determining the contention window adjustment value comprises weighting an identified discontinuous transmission (DTX) as a reported negative acknowledgment (NACK). ### Claim 21 (depends on 18) The apparatus of claim 18, wherein: determining the contention window adjustment value is based at least in part on feedback parameters for a plurality of carriers; and adjusting the contention window size comprises adjusting the contention window size for all of the plurality of carriers. ### Claim 22 (depends on 18) The apparatus of claim 18, wherein the feedback parameter comprises hybrid automatic repeat request (HARQ) feedback for one or more transmission opportunities. ### Claim 23 (depends on 22) The apparatus of claim 22, wherein determining the contention window adjustment value is based at least in part on a number of negative acknowledgement (NACKs) in the HARQ feedback. ### Claim 24 (depends on 18) The apparatus of claim 18, wherein, to determine the feedback parameter, the processor and memory are configured to: determine whether a physical uplink control channel (PUCCH) has been successfully decoded. ### Claim 25 (depends on 18) The apparatus of claim 18, wherein the contention window size corresponds to a transmission opportunity, and the contention window size is adjusted based at least in part on whether the transmission opportunity is self-scheduled or cross-carrier scheduled. ### Claim 26 (depends on 18) The apparatus of claim 18, wherein the processor and memory are configured to: transmit the first transmission over one or more carriers. ### Claim 27 (depends on 26) The apparatus of claim 26, wherein the processor and memory are configured to: transmit the first transmission over a plurality of carriers; and determine a different contention window size for each of the plurality of carriers. ### Claim 28 (depends on 26) The apparatus of claim 26, wherein the processor and memory are configured to: transmit the first transmission over a plurality of carriers; receive a number of negative acknowledgements (NACKs) through hybrid automatic repeat request (HARQ) feedback for each of the plurality of carriers; and adjust the contention window size for the second transmission for all of the plurality of carriers based at least in part on the number of NACKs for all of the plurality of carriers, wherein the contention window size is the same for all of the plurality of carriers. ### Claim 29 (depends on 26) The apparatus of claim 26, wherein the one or more carriers comprise a primary carrier and one or more secondary carriers, and the processor and memory are configured to: start a backoff timer associated with the primary carrier, wherein the backoff timer applies to the one or more secondary carriers. ### Claim 30 (depends on 18) The apparatus of claim 18, wherein the processor and memory are configured to: perform a clear channel assessment based at least in part on the contention window size. ### Claim 31 (depends on 18) The apparatus of claim 18, wherein the processor and memory are configured to: transmit the second transmission on a carrier that is different from a carrier of the first transmission; and refrain from resetting the contention window size. ### Claim 32 (depends on 18) The apparatus of claim 18, wherein the first transmission is sent to one or more UEs, and the processor and memory are configured to: reset the contention window size. ### Claim 33 (depends on 18) The apparatus of claim 18, wherein the feedback parameter comprises an interference indication received in a PUCCH. ### Claim 34 (depends on 18) The apparatus of claim 18, wherein the contention widow size corresponds to a DL transmission opportunity following one or more DL transmission opportunities corresponding to the feedback parameter. ### Claim 35 An apparatus for wireless communications comprising: means for determining a feedback parameter associated with a first transmission; means for determining a contention window adjustment value based at least in part on the feedback parameter, wherein determining the contention window adjustment value comprises weighting a non-reported acknowledgement as a reported negative acknowledgment (NACK); and means for adjusting a contention window size for a second transmission based at least in part on the contention window adjustment value. ### Claim 36 A non-transitory computer-readable medium storing computer-executable code for wireless communications, the code executable by a processor to: determine a feedback parameter associated with a first transmission; determine a contention window adjustment value based at least in part on the feedback parameter, wherein determining the contention window adjustment value comprises weighting a non-reported acknowledgement as a reported negative acknowledgment (NACK); and adjust a contention window size for a second transmission based at least in part on the contention window adjustment value.