Method and apparatus for adjusting a clear channel assessment (CCA) window

Abstract

Techniques and apparatus for wireless communications are described. A base station may determine parameters associated with a transmission, such as hybrid automatic repeat request (HARQ) feedback, a signal-to-noise ratio, or a determination of whether the transmission was successfully decoded. The base station may then determine a contention window adjustment value based on the parameters. The base station may then apply a weighting factor to the contention window adjustment value (e.g., based on the time of the transmission, the number of devices being served, aspects of the transmission parameters, etc.), and may adjust a contention window size for a second transmission based on the weighted contention window adjustment value (and, in some cases, based on other weighted adjustments for other transmissions). The base station may then perform a clear channel assessment (CCA) based on the contention window size.

Description

[0001] This application is a divisional application of an application filed on May 11, 2016, with application number 201680029539.7 (international application number PCT / US2016 / 031918), entitled “Method and apparatus for adjusting a clear channel assessment (CCA) window”.

[0002] Cross-references

[0003] This patent application claims the benefit of U.S. Patent Application No. 15 / 150,790, filed May 10, 2016, by Yerramalli et al., entitled “Techniques for Adjusting Clear Channel Assessment (CCA) Window for Transmissions in a Shared Radio Frequency Spectrum Band,” U.S. Provisional Patent Application No. 62 / 165,928, filed May 23, 2015, by Yerramalli et al., entitled “Techniques for Adjusting Clear Channel Assessment (CCA) Window for Transmissions in a Shared Radio Frequency Spectrum Band,” and U.S. Provisional Patent Application No. 62 / 165,928, filed October 2, 2015, by Yerramalli et al., entitled “Techniques for Adjusting Clear Channel Assessment (CCA) Window for Transmissions in a Shared Radio Frequency Spectrum Band,” and U.S. Provisional Patent Application No. 62 / 165,928, filed October 2, 2015, by Yerramalli et al., entitled “Techniques for Adjusting Clear Channel Assessment (CCA) Window for Transmissions in a Shared Radio Frequency Spectrum Band.” Band (Techniques for Adjusting Clear Channel Assessment (CCA) Window for Transmissions in Shared Radio Frequency Bands), each of which is assigned to the assignee of the present application and is incorporated herein by reference in its entirety. Technical Field

[0004] The present disclosure relates, for example, to wireless communication systems and, more particularly, to techniques for adjusting a clear channel assessment (CCA) window for transmissions in a shared radio frequency band. Background Art

[0005] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcast, etc. These systems may be capable of supporting communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and orthogonal frequency division multiple access (OFDMA) systems (e.g., Long Term Evolution (LTE) systems). A wireless multiple-access communication system may include several base stations, each of which simultaneously supports communication for multiple communication devices, which may also be referred to as user equipment (UE).

[0006] In some cases, a wireless system may operate in a shared or unlicensed radio frequency band.A UE or base station operating in a shared or unlicensed radio frequency band may perform a clear channel assessment (CCA) to verify that the channel is clear before transmitting. Summary of the Invention

[0007] The present disclosure relates, for example, to one or more techniques for adjusting a clear channel assessment (CCA) window for transmissions in a shared radio frequency band. More specifically, these techniques involve identifying (e.g., a base station) a parameter associated with a first transmission, such as hybrid automatic repeat request (HARQ) feedback, a signal-to-noise ratio, or a determination of 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 a weighting factor to the contention window adjustment value (e.g., based on the time of the transmission, the number of devices being served, aspects of the transmission parameters, etc.). The contention window size for the second transmission may then be adjusted based on the weighted contention window adjustment value (and in some cases based on other weighted adjustments for other transmissions). The base station may then perform a clear channel assessment (CCA) based on the contention window size, or may signal the contention window size to a user equipment (UE) that can perform CCA (e.g., for uplink transmissions).

[0008] A method of wireless communication is described. The method may include determining a first parameter associated with a first transmission, determining a first contention window adjustment value based at least in part on the first parameter, applying a first weighting factor to the first contention window adjustment value, and adjusting a contention window size for a second transmission based at least in part on the weighted first contention window adjustment value.

[0009] An apparatus for wireless communication is described. The apparatus may include means for determining a first parameter associated with a first transmission, means for determining a first contention window adjustment value based at least in part on the first parameter, means for applying a first weighting factor to the first contention window adjustment value, and means for adjusting a contention window size for a second transmission based at least in part on the weighted first contention window adjustment value.

[0010] Another apparatus is described. The apparatus may include a processor, a memory in electronic communication with the processor, and instructions stored in the memory. The instructions are operable to cause the processor to determine a first parameter associated with a first transmission, determine a first contention window adjustment value based at least in part on the first parameter, apply a first weighting factor to the first contention window adjustment value, and adjust a contention window size for a second transmission based at least in part on the weighted first contention window adjustment value.

[0011] A non-transitory computer-readable medium for wireless communications is described. The non-transitory computer-readable medium may include instructions for causing a processor to determine a first parameter associated with a first transmission, determine a first contention window adjustment value based at least in part on the first parameter, apply a first weighting factor to the first contention window adjustment value, and adjust a contention window size for a second transmission based on the weighted first contention window adjustment value.

[0012] In some examples of the methods, apparatuses, or non-transitory computer-readable media described above, the first parameter includes hybrid automatic repeat request (HARQ) feedback regarding one or more transmission opportunities. In some examples of the methods, apparatuses, or non-transitory computer-readable media described above, the first contention window adjustment value is based on a number of negative acknowledgments (NACKs) in the HARQ feedback.

[0013] In some examples of the methods, apparatus, or non-transitory computer-readable media described above, the first weighting factor is based on whether the HARQ feedback is in a multiplexing mode. Some examples of the methods, apparatus, or non-transitory computer-readable media described above may further include a process, feature, device, or instruction for reporting a number of acknowledgments (ACKs) or NACKs in a multiplexing mode, wherein the first weighting factor is based on the number of NACKs in the HARQ feedback.

[0014] In some examples of the methods, apparatuses, or non-transitory computer-readable media described above, determining the first contention window adjustment value includes determining the first contention window adjustment value using a lookup table, wherein the lookup table is based on a frame structure of the first transmission. In some examples of the methods, apparatuses, or non-transitory computer-readable media described above, the first transmission is in licensed spectrum.

[0015] In some examples of the methods, apparatus, or non-transitory computer-readable media described above, the first parameter is based on a frame structure of the first transmission. In some examples of the methods, apparatus, or non-transitory computer-readable media described above, the first parameter includes at least one non-reported acknowledgment.

[0016] Some examples of the methods, apparatus, or non-transitory computer-readable media described above may further include a process, feature, apparatus, or instruction for applying a first weighting factor to the first contention window adjustment value for the at least one non-reported acknowledgement differently than the reported NACK.

[0017] In some examples of the methods, apparatus, or non-transitory computer-readable media described above, the contention window size corresponds to an uplink (UL) transmission opportunity. Some examples of the methods, apparatus, or non-transitory computer-readable media described above may further include a process, feature, means, or instruction for transmitting the first transmission on one or more carriers.

[0018] In some examples of the methods, apparatuses, or non-transitory computer-readable media described above, determining the first parameter includes determining whether a physical uplink control channel (PUCCH) has been successfully decoded. In some examples of the methods, apparatuses, or non-transitory computer-readable media described above, a contention window size is adjusted based on whether the UL transmission opportunity is self-scheduled or cross-carrier scheduled. In some examples of the methods, apparatuses, or non-transitory computer-readable media described above, a contention window size is different for the one or more carriers.

[0019] Some examples of the methods, apparatuses, or non-transitory computer-readable media described above may further include a process, feature, device, or instruction for receiving a number of negative acknowledgments (NACKs) via hybrid automatic repeat request (HARQ) feedback for each carrier. Some examples of the methods, apparatuses, or non-transitory computer-readable media described above may further include a process, feature, device, or instruction for determining a first contention window adjustment value based on the number of NACKs for all carriers. Some examples of the methods, apparatuses, or non-transitory computer-readable media described above may further include a process, feature, device, or instruction for adjusting a contention window size for the second transmission for all carriers, wherein the contention window size is the same for all carriers.

[0020] In some examples of the methods, apparatuses, or non-transitory computer-readable media described above, the one or more carriers include a primary carrier and one or more secondary carriers, and the method further includes: starting a backoff timer associated with the primary carrier, wherein the backoff timer applies to the one or more secondary carriers. In some examples of the methods, apparatuses, or non-transitory computer-readable media described above, the one or more secondary carriers are within a predetermined frequency separation relative to the primary carrier.

[0021] In some examples of the methods, apparatuses, or non-transitory computer-readable media described above, the one or more secondary carriers are in an unlicensed information infrastructure radio band. In some examples of the methods, apparatuses, or non-transitory computer-readable media described above, a total number of secondary carriers is less than a predetermined number adjusted based on the weighted second contention window adjustment value.

[0022] Some examples of the methods, apparatuses, or non-transitory computer-readable media described above may further include a process, feature, means, or instruction for performing a clear channel assessment based on a contention window size. Some examples of the methods, apparatuses, or non-transitory computer-readable media described above may further include a process, feature, means, or instruction for applying a first weighting factor to a first contention window adjustment value based on a transmission opportunity corresponding to the first contention window adjustment value.

[0023] In some examples of the methods, apparatuses, or non-transitory computer-readable media described above, applying the first weighting factor to the first contention window adjustment value includes applying a first weighting factor of 0 to the first contention window adjustment value for which the corresponding transmission opportunity falls outside a time period. Some examples of the methods, apparatuses, or non-transitory computer-readable media described above may further include a process, feature, means, or instruction for applying the first weighting factor to the first contention window adjustment value based on an infinite impulse response filter.

[0024] Some examples of the methods, apparatuses, or non-transitory computer-readable media described above may further include a process, feature, means, or instruction for applying a first weighting factor to the first contention window adjustment value based on a user equipment (UE) associated with the first parameter. Some examples of the methods, apparatuses, or non-transitory computer-readable media described above may further include a process, feature, means, or instruction for applying a first weighting factor to the first contention window adjustment value based on whether a grant associated with the first parameter is a valid grant.

[0025] Some examples of the methods, apparatus, or non-transitory computer-readable media described above may further include a process, feature, means, or instruction for applying a first weighting factor to the first contention window adjustment value. Some examples of the methods, apparatus, or non-transitory computer-readable media described above may further include a process, feature, means, or instruction for applying a first weighting factor to the first contention window adjustment value for the at least one non-reported acknowledgment in the same manner as a reported NACK.

[0026] Some examples of the methods, apparatuses, or non-transitory computer-readable media described above may further include a process, feature, means, or instruction for transmitting the second transmission on a carrier different from the carrier of the first transmission. Some examples of the methods, apparatuses, or non-transitory computer-readable media described above may further include a process, feature, means, or instruction for refraining from resetting the contention window size. In some examples of the methods, apparatuses, or non-transitory computer-readable media described above, the first transmission is sent to one or more UEs, and the method further includes resetting the contention window size.

[0027] Some examples of the methods, apparatuses, or non-transitory computer-readable media described above may further include a process, feature, means, or instruction for resetting the contention window size based on a duration elapsed after the second transmission. In some examples of the methods, apparatuses, or non-transitory computer-readable media described above, determining a first parameter associated with the first transmission further includes receiving at least one acknowledgment (ACK) indication from each of the one or more UEs based on the first transmission.

[0028] Some examples of the methods, apparatus, or non-transitory computer-readable media described above may further include a process, feature, means, or instruction for receiving an acknowledgment (ACK) and a negative acknowledgment (NACK) indication based on the first transmission. Some examples of the methods, apparatus, or non-transitory computer-readable media described above may further include a process, feature, means, or instruction for determining a first parameter associated with the first transmission, wherein the first parameter includes a percentage of ACKs relative to a total number of supported user equipment (UEs).

[0029] Some examples of the methods, apparatuses, or non-transitory computer-readable media described above may further include a process, feature, means, or instruction for applying a first weighting factor to the first contention window adjustment value based on a size of the transmission opportunity or a resource allocation associated with the first parameter. Some examples of the methods, apparatuses, or non-transitory computer-readable media described above may further include a process, feature, means, or instruction for receiving at least one ACK indication from each of the one or more UEs.

[0030] Some examples of the methods, apparatuses, or non-transitory computer-readable media described above may further include a process, feature, device, or instruction for applying a first weighting factor to the first contention window adjustment value based on a block error rate (BLER) target associated with the first parameter. In some examples of the methods, apparatuses, or non-transitory computer-readable media described above, the number of UEs is greater than a threshold, and the method further includes receiving at least one ACK indication from a predetermined percentage of UEs.

[0031] In some examples of the methods, apparatuses, or non-transitory computer-readable media described above, a first transmission is sent to one or more UEs, and the method further includes: dividing the one or more UEs into one or more UE groups based on the contention window size of the one or more UEs. In some examples of the methods, apparatuses, or non-transitory computer-readable media described above, the method further includes randomly generating a counter for the one or more UE groups. Some examples of the methods, apparatuses, or non-transitory computer-readable media described above may further include a process, feature, device, or instruction for starting a counter for the one or more UE groups. Some examples of the methods, apparatuses, or non-transitory computer-readable media described above may further include a process, feature, device, or instruction for transmitting a second transmission to the UE group whose counter expires.

[0032] In some examples of the methods, apparatuses, or non-transitory computer-readable media described above, the first parameter includes an interference indication received in a PUCCH. Some examples of the methods, apparatuses, or non-transitory computer-readable media described above may further include a process, feature, means, or instruction for applying a first weighting factor to the first contention window adjustment value based on a carrier aggregation configuration or a coordinated multi-point configuration.

[0033] Some examples of the methods, apparatuses, or non-transitory computer-readable media described above may further include a process, feature, means, or instruction for randomly selecting a first UE group from two or more UE groups, wherein the counters of the two or more UE groups are the same value. Some examples of the methods, apparatuses, or non-transitory computer-readable media described above may further include a process, feature, means, or instruction for transmitting a second transmission to the first UE group.

[0034] Some examples of the methods, apparatus, or non-transitory computer-readable media described above may further include a process, feature, apparatus, or instruction for applying a first weighting factor to the first contention window adjustment value based on whether the first parameter corresponds to a broadcast channel.

[0035] Some examples of the methods, apparatuses, or non-transitory computer-readable media described above may further include a process, feature, device, or instruction for randomly regenerating a counter for the one or more UE groups after the second transmission. Some examples of the methods, apparatuses, or non-transitory computer-readable media described above may further include a process, feature, device, or instruction for applying a first weighting factor to the first contention window adjustment value based on whether the first parameter corresponds to a user equipment (UE) that implements or is capable of interference cancellation.

[0036] Some examples of the methods, apparatuses, or non-transitory computer-readable media described above may further include a process, feature, means, or instruction for stopping the counters of the one or more UE groups based on the expiration of the counters of the UE groups for which the counters have expired. Some examples of the methods, apparatuses, or non-transitory computer-readable media described above may further include a process, feature, means, or instruction for retaining the values ​​of the counters of the one or more UE groups for a third transmission.

[0037] In some examples of the method, apparatus, or non-transitory computer-readable medium described above, the contention window size corresponds to a DL transmission opportunity that follows one or more DL transmission opportunities corresponding to the first parameter.

[0038] A method of wireless communication is described. The method may include transmitting a message to a base station; receiving a contention window size from the base station, wherein the contention window size is calculated based at least in part on the message using a first weighting factor applied to a first contention window adjustment value; and performing a clear channel assessment based at least in part on the contention window size.

[0039] An apparatus for wireless communication is described. The apparatus may include: means for transmitting a message to a base station; means for receiving a contention window size from the base station, wherein the contention window size is calculated based at least in part on the message using a first weighting factor applied to a first contention window adjustment value; and means for performing a clear channel assessment based at least in part on the contention window size.

[0040] Another apparatus is described. The apparatus may include a processor, a memory in electronic communication with the processor, and instructions stored in the memory. The instructions are operable to cause the processor to: transmit a message to a base station; receive a contention window size from the base station, wherein the contention window size is calculated based at least in part on the message using a first weighting factor applied to a first contention window adjustment value; and perform a clear channel assessment based at least in part on the contention window size.

[0041] A non-transitory computer-readable medium for wireless communication is described. The non-transitory computer-readable medium may include instructions for causing a processor to: transmit a message to a base station; receive a contention window size from the base station, wherein the contention window size is calculated based on the message using a first weighting factor applied to a first contention window adjustment value; and perform a clear channel assessment based at least in part on the contention window size.

[0042] In some examples of the methods, apparatus, or non-transitory computer-readable media described above, transmitting a message to a base station includes transmitting a bit indicating that at least one transport block in a downlink transmission was successfully decoded, wherein the contention window size is based on the transmitted bit.

[0043] In some examples of the methods, apparatuses, or non-transitory computer-readable media described above, transmitting a message to the base station includes transmitting a bit indicating that at least one code block in a downlink transmission was successfully decoded, wherein the contention window size is based on the transmitted bit. In some examples of the methods, apparatuses, or non-transitory computer-readable media described above, transmitting a message to the base station includes transmitting data on a physical uplink shared channel (PUSCH).

[0044] Some examples of the methods, apparatus, or non-transitory computer-readable media described above may further include processes, features, means, or instructions for detecting collisions during downlink transmissions. Some examples of the methods, apparatus, or non-transitory computer-readable media described above may further include processes, features, means, or instructions for transmitting a message to a base station, the transmitting the message to the base station comprising transmitting a bit indicating the collision, wherein the contention window size is based on the transmitted bit.

[0045] The foregoing has broadly outlined the features and technical advantages of examples according to the present disclosure in an effort to make the following detailed description better understood. Additional features and advantages will be described hereinafter. The concepts and specific examples disclosed can be readily used as a basis for modifying or designing other structures for implementing the same purposes as the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. The characteristics of the concepts disclosed herein, both in terms of their organization and method of operation, as well as the associated advantages, will be better understood by considering the following description in conjunction with the accompanying drawings. Each of the figures is provided for illustration and description purposes and does not define limitations on the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] A further understanding of the nature and advantages of the present invention may be achieved by referring to the following drawings. In the drawings, similar components or features may have the same reference number. In addition, components of the same type may be distinguished by following the reference number with a dash and a second reference number that distinguishes between similar components. If a first reference number is used in the specification, the description applies to any of the similar components having the same first reference number, regardless of the second reference number.

[0047] Figure 1 An example of a wireless communication system supporting adjustment of a CCA window according to aspects of the present disclosure is illustrated;

[0048] Figure 2 An example of a wireless communication subsystem supporting adjustment of a CCA window according to aspects of the present disclosure is illustrated;

[0049] Figure 3 illustrates examples of contention window adaptation according to aspects of the present disclosure;

[0050] Figure 4 illustrates an example of a process flow supporting adjustment of a CCA window according to aspects of the present disclosure;

[0051] Figure 5 and 6 A block diagram of a wireless device supporting CCA window adaptation according to aspects of the present disclosure is shown;

[0052] Figure 7 A block diagram illustrating a CCA adaptation component, which may be a component of a wireless device for CCA window adaptation, according to aspects of the present disclosure;

[0053] Figure 8 illustrates a block diagram of a system including a UE supporting CCA window adaptation according to aspects of the present disclosure;

[0054] Figure 9 and 10 A block diagram of a wireless device supporting CCA window adaptation according to aspects of the present disclosure is shown;

[0055] Figure 11 A block diagram illustrating a base station CCA adaptation component, which may be a component of a wireless device for CCA window adaptation, according to aspects of the present disclosure;

[0056] Figure 12 A block diagram illustrating a system including a base station supporting CCA window adaptation according to aspects of the present disclosure; and

[0057] Figures 13 to 21 A flow chart illustrating a CCA window adaptation method according to aspects of the present disclosure is shown. DETAILED DESCRIPTION

[0058] Techniques are described in which a shared radio frequency band is used for at least a portion of communications on a wireless communication system. In some examples, the shared radio frequency band may be used for LTE / LTE-A communications. The shared radio frequency band may be used in combination with a dedicated radio frequency band or independently of a dedicated radio frequency band. A dedicated radio frequency band may be a radio frequency band that a transmitting device may not contend for access because the radio frequency band is licensed to a specific user (e.g., a licensed radio frequency band that may be used for LTE / LTE-A communications). A shared radio frequency band may be a radio frequency band that devices may need to contend for access (e.g., a radio frequency band that may be used for unlicensed use (such as Wi-Fi use) or a radio frequency band that may be available for use by multiple operators on an equally shared or prioritized basis).

[0059] In some wireless systems, devices may monitor the medium or channel for a period of time before sending data to prevent collisions. For example, a device may use a clear channel assessment (CCA). If a device senses that the channel is idle, it may wait for a backoff period before attempting to transmit. This backoff period can reduce the chance of collisions when multiple devices are attempting to transmit simultaneously. In some cases, the backoff period may be randomly selected up to a predefined maximum value. The maximum backoff period may be referred to as a contention window (CW).

[0060] In some cases, collisions may still occur and data may not be successfully transmitted. In such cases, the length of the CW can be increased, which can give multiple devices more opportunities to successfully transmit. For example, in some cases, the length of the CW can be doubled (exponential backoff) for each instance of unsuccessful transmission, as in wireless local area networks (WLANs). Other methods for determining the length of the CW may be beneficial.

[0061] As described herein, the downlink CW may be adapted based on ACK / NACK feedback from a previous transmit opportunity (TXOP). For example, a weighting factor may be applied to an adjustment parameter for determining the CW. Examples of adjustment parameters may include HARQ feedback, signal-to-noise ratio, or a determination of whether a transmission was successfully decoded. In some cases, the weighting factor may be dynamically implemented based on each of the previous TXOPs. The weighting of each ACK / NACK in a TXOP may depend on several factors. In some cases, a multiplexed ACK / NACK may have a lower weight than an individual ACK / NACK. For multiplexed ACK / NACK, the weighting may depend on the number of multiplexed bits. Alternatively, in addition to the multiplexed ACK / NACK, the UE may also indicate the number of ACK or NACK bits. The weighting may also depend on whether the ACK / NACK is reported.

[0062] The uplink CW may also be adapted. In some cases, the CW size to be used may be signaled to the UE by the base station. As long as there is a common understanding of the transmission boundaries, different users may be signaled different values. The window size or a change in the window size may be granted as part of a common downlink control information grant or signaled in an uplink grant. The adaptation algorithm for the UE window size may reuse applicable concepts from the base station. In some cases, if the physical uplink control channel (PUCCH) is error correction coded (e.g., cyclic redundancy check (CRC) coded), then in addition to the physical uplink shared channel (PUSCH), PUCCH successful decoding (or unsuccessful decoding) may also be used for window adaptation. In other cases, the window size may depend on whether the uplink is self-scheduled or cross-carrier scheduled.

[0063] Various aspects of the present disclosure are initially described in the context of a wireless communication system. A specific example of a clear channel assessment process is subsequently described. These and other aspects of the present disclosure are further illustrated and described by and with reference to apparatus diagrams, system diagrams, and flow charts relating to CCA window adaptation.

[0064] Figure 1 An example of a wireless communication system 100 that supports adjustment of a CCA window according to aspects of the present disclosure is illustrated. The wireless communication system 100 includes a base station 105, a user equipment (UE) 115, and a core network 130. In some examples, the wireless communication system 100 can be a long term evolution (LTE) / LTE-Advanced (LTE) network. In some examples, the wireless communication system 100 can operate in a shared or unlicensed spectrum such that the base station 105 and the UE 115 perform a CCA procedure before transmitting on at least one wireless channel. The base station 105 can dynamically determine to change the contention window size based on a previous uplink (UL) or downlink (DL) transmission opportunity.

[0065] CCA can include energy detection procedures to determine whether there are any other active transmissions. For example, a device can infer that changes in a power meter's received signal strength indicator (RSSI) indicate that the channel is occupied. Specifically, signal power concentrated in a certain bandwidth and exceeding a predetermined noise floor can indicate another wireless transmitter. CCA can also include detection of specific sequences that indicate channel usage. For example, another device can transmit a specific preamble before transmitting a data sequence.

[0066] In general, base stations 105 can communicate wirelessly with UEs 115 via one or more base station antennas. Each base station 105 can provide communication coverage for a corresponding geographic coverage area 110. The communication links 125 shown in the wireless communication system 100 can include uplink (UL) transmissions from the UE 115 to the base station 105, or downlink (DL) transmissions from the base station 105 to the UE 115. The UEs 115 can be dispersed throughout the wireless communication system 100, and each UE 115 can be stationary or mobile. The UEs 115 can also be referred to as mobile stations, subscriber stations, remote units, wireless devices, access terminals, handsets, user agents, clients, or some other suitable terminology. The UEs 115 can also be cellular phones, wireless modems, handheld devices, personal computers, tablet devices, personal electronic devices, machine type communication (MTC) devices, etc.

[0067] Base stations 105 can communicate with core network 130 and with each other. For example, base stations 105 can interface with core network 130 via backhaul links 132 (e.g., S1, etc.). Base stations 105 can communicate with each other directly or indirectly (e.g., through core network 130) via backhaul links 134 (e.g., X2, etc.). Base stations 105 can perform radio configuration and scheduling for communication with UE 115, or can operate under the control of a base station controller (not shown). In some examples, base stations 105 can be macro cells, small cells, hotspots, etc. Base stations 105 can also be referred to as evolved Node Bs (eNBs) 105.

[0068] Because the communication link 125 may be subject to path loss, interference, and other forms of signal degradation, the wireless communication system 100 may employ various means to increase communication reliability. For example, hybrid automatic repeat request (HARQ) is a method for ensuring that data is correctly received on the wireless communication link 125. Hybrid automatic repeat request (HARQ) may include a combination of error detection (e.g., using a cyclic redundancy check (CRC)), forward error correction (FEC), and retransmission (e.g., automatic repeat request (ARQ)). HARQ can improve throughput at the media access control (MAC) layer in poor radio conditions (e.g., signal-to-noise ratio conditions). In incremental redundancy HARQ, incorrectly received data can be stored in a buffer and combined with subsequent transmissions to improve the overall probability of successfully decoding the data. In some cases, redundant bits are added to each message before transmission. This can be particularly useful in poor conditions. In other cases, redundant bits are not added to each transmission, but are retransmitted after the transmitter of the original message receives a negative acknowledgement (NACK) indicating a failed attempt to decode the information. This chain of transmission, response, and retransmission may be referred to as a HARQ process. In some cases, a limited number of HARQ processes may be used for a given communication link 125.

[0069] According to the present disclosure, HARQ feedback can also be a means of determining whether a transmission opportunity is subject to interference from another wireless device on a shared channel. For example, if base station 105 receives a large number of NACKs, or if it does not receive the expected HARQ feedback, the base station can infer that a transmission collision has occurred. As a result, the length of the contention window for CCA can be increased.

[0070] HARQ feedback may be sent in a physical uplink control channel (PUCCH). PUCCH is also used for scheduling requests (SRs) and channel quality indicators (CQIs) as well as other UL control information. The physical uplink control channel (PUCCH) may be mapped to a control channel defined by a code and two consecutive resource blocks. UL control signaling may depend on the presence of timing synchronization of the cell. PUCCH resources for scheduling requests (SRs) and channel quality indicator (CQI) reporting may be assigned (and revoked) via radio resource control (RRC) signaling. In some cases, resources for SR may be assigned via a random access channel (RACH) procedure after synchronization is acquired. In other cases, SR may not be assigned to UE 115 via RACH (i.e., a synchronized UE may or may not have a dedicated SR channel). When the UE is no longer synchronized, the PUCCH resources for SR and CQI may be lost. In some cases, the base station may calculate the contention window size based at least in part on whether the PUCCH is successfully decoded.

[0071] In some cases, the wireless communication system 100 may utilize one or more enhanced component carriers (eCCs). An enhanced component carrier (eCC) may be characterized by one or more features, including flexible bandwidth, different transmission time intervals (TTIs), and a modified control channel configuration. In some cases, an eCC may be associated with a carrier aggregation (CA) configuration or a dual connectivity configuration (e.g., when multiple serving cells have suboptimal backhaul links). An eCC may also be configured for use in an unlicensed spectrum or a shared spectrum (e.g., where more than one operator is licensed to use the spectrum). An eCC characterized by flexible bandwidth may include one or more segments that may be utilized by UEs 115 that are unable to monitor the entire bandwidth or prefer to use a limited bandwidth (e.g., to save power).

[0072] In some cases, an eCC may utilize a different TTI length than other component carriers (CCs), which may include using a reduced or variable symbol duration compared to the TTIs of other CCs. The symbol duration may remain the same in some cases, but each symbol may represent a different TTI. In some examples, an eCC may include multiple layers associated with different TTI lengths. For example, the TTI at one layer may correspond to a uniform 1ms subframe, while in a second layer, variable-length TTIs may correspond to bursts of short-duration symbol periods. In some cases, the shorter symbol duration may also be associated with an increased subcarrier spacing. In conjunction with the reduced TTI length, the eCC may utilize dynamic time division duplex (TDD) operation (i.e., the eCC may switch from downlink (DL) to UL operation for short bursts based on dynamic conditions).

[0073] Flexible bandwidth and variable TTIs may be associated with modified control channel configurations (e.g., an eCC may use the enhanced physical downlink control channel (ePDCCH) for DL ​​control information). For example, one or more control channels of an eCC may utilize frequency division multiplexing (FDM) scheduling to accommodate flexible bandwidth usage. Other control channel modifications include the use of additional control channels (e.g., for evolved multimedia broadcast multicast service (eMBMS) scheduling or to indicate the length of variable-length UL and DL bursts) or control channels transmitted at different intervals. The eCC may also include modified or additional HARQ-related control information.

[0074] Thus, the base station 105 may determine parameters associated with the transmission, such as HARQ feedback, signal-to-noise ratio, or a determination of whether the transmission was successfully decoded. The base station 105 may then determine a contention window adjustment value based on the parameters. The base station 105 may then apply a weighting factor to the contention window adjustment value (e.g., based on the time of the transmission, the number of devices being served, aspects of the transmission parameters, etc.). The contention window size for the second transmission may then be adjusted based on the weighted contention window adjustment value (and in some cases based on other weighted adjustments for other transmissions). The base station 105 may then perform a clear channel assessment (CCA) based on the contention window size or may signal the contention window size to the UE 115 that may perform CCA (e.g., for uplink transmissions).

[0075] Figure 2 An example of a wireless communication subsystem 200 that supports adjustment of a CCA window according to aspects of the present disclosure is illustrated. The wireless communication subsystem 200 may include a UE 215, a UE 220, and a base station 205 (which may be referenced to Figure 11 and 2. The wireless communication subsystem 200 may be configured to communicate with the base station 205 using a radio access technology (RAT) system. For example, the UE 215 may communicate with the base station 205 over a communication link 225, and the UE 220 may communicate with the base station 205 over a communication link 230. The wireless communication subsystem 200 may also include a wireless device 206, which may be using a different RAT in the same spectrum. For example, the wireless device 206 may be a station or access point in a wireless local area network (WLAN). The base station 205 may dynamically adapt the contention window size for the purpose of performing the CCA procedure. For example, the base station 205 may determine a parameter associated with the first transmission and may determine a contention window adjustment value based at least in part on the parameter. The base station 205 may then apply a weighting factor to the contention window adjustment value and may then adjust the contention window size for the second transmission based at least in part on the weighted first contention window adjustment value.

[0076] The base station 205 may monitor the medium or channel for a period of time before sending data to prevent collisions (e.g., collisions with transmissions from the wireless device 206). The base station 205 may use a clear channel assessment (CCA) to sense the channel. If the base station 205 senses that the channel is idle, it may wait for a backoff period before attempting to transmit. In some cases, the backoff period may be randomly selected up to a predefined maximum value. The maximum backoff period may be referred to as a contention window (CW). In some cases, collisions may still occur and data may not be successfully transmitted. In such cases, the length of the CW may be increased, which may give multiple devices more opportunities to transmit successfully.

[0077] In addition to channel contention procedures, wireless systems may have different procedures for acknowledgment / negative acknowledgment (ACK / NACK) of data transmissions. These procedures may be different for different radio access technologies (RATs). For example, in WLAN, ACK / NACK may occur immediately after transmission, block ACK may be possible, ACK may not be subject to listen-before-talk (LBT), ACK / NACK may not be multiplexed, and there may be only one ACK / NACK bit per core block. In other wireless systems (e.g., cellular wide area network systems), ACK / NACK may lag in time from the end of the transmission, each transmission block may be acknowledged in a separate subframe in the primary cell, ACK may be subject to LBT (e.g., when transmitting on a secondary cell), ACK / NACK may be partially multiplexed, and ACK / NACK may depend on carrier aggregation.

[0078] Different wireless systems may also have different methods for handling multiple users. For example, in WLANs, multiple users can be accommodated through spatial multiplexing, while in other wireless systems (such as cellular wide area network systems), multiplexing can be achieved through time division multiplexing (TDM), frequency division multiplexing (FDM), spatial multiplexing, or any combination thereof. Carrier priority may also depend on the type of wireless system. For example, in WLANs, carrier sense multiple access (CSMA) may only be performed on the primary carrier and CCA may be performed on the secondary carrier, while in some cellular networks, CCA may be performed independently on each carrier. In some cases, outer loop power control management may be different for different wireless systems. For example, in WLANs, a limited number of users may help limit backoff, while in cellular systems, running the outer loop at a higher block error rate (BLER) may lead to errors. Additionally, different wireless systems may have different hybrid automatic repeat request (HARQ) capabilities, different ACK / NACK procedures for broadcast packets, or different coordinated multipoint (CoMP) capabilities. For example, in WLAN, HARQ may not be performed, broadcast packets may be sent via beacons and may not be acknowledged, and CoMP may not be supported. In the case of cellular networks, they may use HARQ, may not ACK / NACK broadcast channels, and may support CoMP.

[0079] As described herein, the downlink CW may be adapted based on ACK / NACK feedback from the UE 215 from a previous transmit opportunity (TXOP). For example, the base station 205 may apply a weighting factor to each adjustment parameter used to determine the CW. In some cases, the weighting factor may be implemented dynamically based on each of the previous TXOPs. In one possible scenario, the weighting may be based on the number of ACK / NACKs received from the UE 215 in a time window corresponding to the previous Nms or the previous N TXOPs, where any earlier ACK / NACKs may be discarded. In this case, N may be a predetermined variable. In another example, the weighting may be based on a filtering algorithm, such as an infinite impulse response (IIR) filter. For example, the CW width at the upcoming transmit opportunity may be given by

[0080] CW[TXOP(M+1)]=CW[TXOP(M)]+(1-x)CW 调整 , (1)

[0081] x=CW[TXOP(M)]. (2)

[0082] That is, where CW[TXOP(M)] is the CW width of the current TXOP, x is the window size at M relative to some maximum window size, and CW 调整is a CW adjustment factor that may depend on one or more factors described herein. In some cases, if the base station 205 is idle for a configured period of time without accessing the channel, the CW may be reset to a minimum value, for example.

[0083] As discussed, the contention window size can be a function of several parameters, including the number of ACKs or NACKs received. In some cases, the number of ACKs or NACKs received at the base station 205 within a defined observation period can be used to determine how to adjust the contention window size. The duration of the observation period can depend on several factors. For example, the duration can be fixed. In other examples, the duration can depend on the frame structure used for the transmission. If multiple carriers are used, the duration can depend on the frame structure of the primary cell. For example, for one frame structure, the time period can begin n+4 ms after the transmission begins on the secondary cell and can end n+4 ms after the transmission ends. Alternatively, for example, a table can be used to define the observation period for each possible frame structure (e.g., each TDD frame structure). If there is no ongoing transmission, the contention window size can be adjusted based on the most recently available observation period. In some cases, if there is no ongoing transmission for a certain time duration that can be predetermined, the contention window size can be reset to the initial size.

[0084] In some cases, communication may occur across multiple carriers, and feedback may be received for each carrier. For example, communication link 225 may comprise multiple carriers. The contention window size may be adjusted independently for each carrier or based on feedback from all carriers. For example, if each carrier independently performs listen-before-talk (LBT), the contention window size may be independently determined, which may depend on the ACK / NACK received for that carrier. Alternatively, the contention window size may be determined based on the ACK / NACK received for all carriers, with the resulting contention window size then being used for all carriers. In such cases, the backoff timer countdown may still be independent for each carrier. In other examples, a primary carrier may perform the countdown on behalf of other carriers (e.g., secondary carriers). In such cases, the contention window size may be determined based on the ACK / NACK feedback received for all carriers. In some cases, restrictions may be placed on what constitutes a secondary carrier. For example, restrictions may be placed on the frequency separation between the primary carrier and the secondary carrier. Alternatively, restrictions may be placed on the total number of secondary carriers associated with the primary carrier. In other cases, the secondary carrier may be restricted to a specific sub-band (eg, the Unlicensed Information Infrastructure (U-NII) radio band).

[0085] In some instances, there may be multiple carrier groups, each with a primary carrier. The base station 205 may switch carriers for the next transmission. If so, the contention window size may not be reset. For example, if retransmissions are on different carriers, the contention window size may not be reset to maintain consistent contention window size updates.

[0086] The weighting of each ACK / NACK in a TXOP may depend on several factors. In some cases, the multiplexed ACK / NACK may have a lower weight than the individual ACK / NACKs sent by the UE 215. For the multiplexed ACK / NACK, the weighting may depend on the number of multiplexed bits. Alternatively, in addition to the multiplexed ACK / NACK, the UE 215 may also indicate the number of ACK or NACK bits. The weighting may also depend on whether the ACK / NACK is reported. For example, if the UE 215 does not report an ACK / NACK, this may indicate that the control channel was not decoded, which may indicate a more serious problem than a NACK report. Because the NACK is not reported, the base station 205 may inherently know that discontinuous transmission (DTX) has occurred. In some cases, DTX may be treated the same as NACK. In other cases, DTX may be treated differently, for example, DTX may be weighted more heavily than NACK. In other cases, the UE 215 may decode the packet header but fail to decode any media access control protocol data unit (MPDU), which may be treated as a DTX scenario. In other cases, for CW weighting considerations, ACK / NACKs based on invalid grants transmitted by the base station 205, for example, during cross-carrier scheduling, may be discarded. For example, such grants may be discarded based on channel usage beacon signal (CUBS) detection.

[0087] In some cases, UE 215 may be unable to transmit a previously transmitted ACK / NACK because the carrier is occupied. For example, UE 215 may perform LBT and determine that the carrier is occupied and not transmit. As a result, base station 205 may not receive the feedback required to determine the contention window size. If LBT fails for UE 215, base station 205 may refrain from using the missing ACK / NACKs for calculating the window size. In some cases, the observation period for receiving ACK / NACKs may be redefined when transmitting ACK / NACKs on an unlicensed carrier, which may help ensure that all reported ACK / NACKs are utilized.

[0088] The number of users in the wireless communication subsystem 200 and the size of the TXOP may also influence the weighting. For example, a user with data on the order of fewer resource blocks per subframe may have a smaller impact on CW adaptation than another user with more resource blocks allocated per subframe. In this case, the ACK / NACK results for all users may be weighted for CW adaptation. For example, the number of allocated resource blocks may be used for weighting. In another case, the outer loop BLER target for each user may be considered when adjusting its contribution to changes in CW size. For example, a user with an outer loop BLER target of 30% may experience more decoding failures than a user with an outer loop BLER target of 10%.

[0089] The following discussion provides several non-limiting options for determining or modifying the contention window size. In the first option, the contention window size can be doubled when a NACK is reported for all transmissions within the observation period. For example, UE 215 and UE 220 will report a NACK for all subframes on all carriers. This option may not be preferred because it provides several ways to prevent the contention window size from increasing. In the second option, if each of UE 215 and UE 220 reports at least one ACK, the contention window size can be reset, that is, if one UE (e.g., UE 215) reports all NACKs, the contention window size is increased. This can, for example, reduce the incentive for base station 205 to schedule a low modulation and coding scheme (MCS) for one user so as not to increase its contention window size.

[0090] In the third option, if the percentage of received ACKs received during the observation period exceeds a configured threshold, the contention window size may be reset. In some cases, the threshold may be 50%. In some aspects, the ACK or threshold may be weighted based on the number of resource blocks allocated for the grant, which may hinder the base station 205 from transmitting a smaller number of resource blocks to the UE 215 and UE 220 to meet the threshold. In other aspects, the weighting may be based on the difference between the reported channel quality indicator (CQI) and the preferred CQI, or the difference between the reported MCS and the MCS used for transmission. For example, if the MCS used for transmission is greater than the reported MCS, the relative weight may be reduced and vice versa.

[0091] In option 4, some combination of options 2 and 3 may be used. For example, if both UE 215 and UE 220 report at least one ACK and the percentage of ACKs exceeds a certain threshold, the contention window size may be reset. Some aspects of option 4 may depend on the number of scheduled UEs. For example, if the number of scheduled UEs exceeds a threshold (e.g., 4 UEs), a certain percentage of UEs may report at least one ACK, rather than all UEs reporting at least one ACK.

[0092] In the fifth option, the base station 205 can set a contention window size for each UE (e.g., both UE 215 and UE 220). In some aspects, the UE set can be divided into groups based on its current contention window size. For example, UE 215 can represent one group, and UE 220 can represent a second group. Subsequently, a random number can be generated for each UE group, wherein the random number corresponds to a backoff timer. When the backoff timer expires for one of these groups (the group with the smallest number initially), the base station 205 can transmit to that UE group. If two groups have the same number, the base station 205 can randomly select a group to transmit to. In one aspect, each UE group can have a new number generated after the transmission. In a different aspect, the timer can be stopped for other UE groups while the transmission is in progress, and the value of the timer when it is stopped can be retained and used for subsequent transmissions.

[0093] To help implement the above techniques or options, UE 215 can report various types of feedback to base station 205 based on previous transmissions. In some cases, UE 215 can report ACK / NACK feedback without bundling. In other cases, UE 215 can bundle ACK / NACK feedback, which can result in reporting a NACK even when one or more PDSCH transmissions (i.e., transport blocks) are successfully decoded. In such instances, UE 215 can transmit a bit indicating the presence of at least one ACK, even if the bundled feedback results in a NACK. Alternatively, a bit can be sent to indicate whether any code block was successfully decoded, which base station 205 can use to modify the contention window size.

[0094] Downlink CW adaptation may also depend on collision detection and reporting by the UE 215. For example, the UE 215 may detect a drop in the signal-to-interference-plus-noise ratio (SINR) in a given subframe and may report this to the base station 205, for example, using a 1-bit on the physical uplink control channel (PUCCH). In some cases, this bit may be used as an input to the CW adaptation algorithm. In other cases, the CW may be adapted to reduce variations in CW size across carriers or across CoMP transmission points. For example, ACK / NACK results for all carriers may be used to adjust the CW size.

[0095] In some cases, the broadcast channel may not be considered for CW adaptation. For example, the wireless communication subsystem 200 may only transmit the evolved multimedia broadcast multicast service (eMBMS), in which case CW adaptation may consider other metrics, such as the number of interferers for adaptation (e.g., a determination of the number of interferers based on UE 215 reports or base station 205 sensing). In other cases, window adaptation may use different weights to adjust the contributions of users that may perform different levels of interference cancellation, such as in non-orthogonal multiple access (NOMA) or superposition coding. In another case, if the UE 215 has a receiver with interference cancellation (IC) capability, different weights may be applied. This may involve the UE 215 signaling its IC capability to the base station 205.

[0096] The uplink CW may also be adapted. In some cases, the CW size to be used may be signaled to the UE 215 by the base station 205. As long as there is a common understanding of the transmission boundary, different users may be signaled different values. The window size or a change in the window size may be granted as part of a common downlink control information or signaled in an uplink grant. The adaptation algorithm for the UE 215 CW size may reuse the applicable concept from the base station 205. In some cases, if the PUCCH is error-correcting coded (e.g., cyclic redundancy check (CRC) coded), in addition to the physical uplink shared channel (PUSCH), PUCCH successful decoding (or unsuccessful decoding) may also be used for window adaptation. In other cases, the window size may depend on whether the uplink is self-scheduled or cross-carrier scheduled.

[0097] Figure 3 An example of contention window adaptation 300 according to aspects of the present disclosure is illustrated. The contention window adaptation 300 may be implemented by referring to Figure 1-2 The described UE 115 and base station 105 utilize. That is, contention window adaptation 300 represents an example of base station 105 adapting the contention window based on previous transmission opportunities. In some cases, the adaptation can be based on multiple previous transmission opportunities, uplink and downlink opportunities, and transmission opportunities of multiple different UEs 115.

[0098] In some cases, the base station 105 may monitor the medium or channel for a period of time before sending data to prevent collisions. If the base station 105 senses that the channel is idle, it may wait for a backoff period 310 before attempting to transmit. In some cases, the backoff period 310 may be randomly selected up to a predefined maximum value. The maximum backoff period may be referred to as a contention window (CW). In some cases, collisions may still occur. In such cases, the length of the CW may be increased, which may give multiple devices more opportunities to successfully transmit.

[0099] Time periods 305-a, b, c, d, and e may represent base station 105 performing carrier sensing. If base station 105 determines that a carrier is available during time period 305-a, base station 105 may enter a backoff period. Backoff periods 310-a, 310-b, and 310-c may represent time periods after a transmission collision is detected. This backoff period may be randomly selected from a range of values, which may be represented by contention windows 307-a, 307-b, and 307-c. That is, backoff period 310-a may be less than or equal to contention window 307-a. Upon expiration of backoff period 310-a, base station 105 may perform carrier sensing during time period 305-b. If a carrier is available, it may subsequently transmit. Transmission opportunities 315-a and 315-b may represent these time periods available for transmission.

[0100] After the transmission, the base station 105 may adjust the contention window size. This adjustment may depend on several factors described in the present disclosure, such as, but not limited to, the number of NACKs received from the UE 115. For subsequent transmissions, the base station 105 may sense the medium again in time period 305-c and enter a backoff period 310-b if the carrier is available. The contention window 307-b may be the maximum possible backoff period and may be adjusted from the previous transmission. After the backoff period 310-b expires, the base station 105 may sense the carrier again in time period 305-d. If the carrier is busy, it may enter a backoff period 310-c. Upon expiration of the backoff period 310-c, the base station 105 may sense the carrier again in time period 305-e. If the carrier is idle, it may then transmit in a transmission opportunity 315-b.

[0101] Figure 4 An example of a process flow 400 for supporting adjustment of a CCA window according to aspects of the present disclosure is illustrated. The process flow 400 may include a UE 415 and a base station 405, which may be referenced Figure 1 Examples of UE 115 and base station 105 are described and may be referenced. Figure 2 An example of a UE 215 and a base station 205 is depicted. In some examples, UE 415 may represent multiple UEs.

[0102] At 420, base station 405 may perform a clear channel assessment based on the contention window size. At 425, base station 405 may transmit a message to UE 415. In some cases, the transmission at 425 may be on one or more carriers. For example, there may be a primary carrier and one or more secondary carriers. In some cases, the one or more secondary carriers may be within a predetermined frequency separation relative to the primary carrier. Additionally, the one or more secondary carriers may be in an unlicensed information infrastructure radio band, or the total number of secondary carriers may be less than a predetermined number.

[0103] At 430, UE 415 may transmit a message to base station 405, which may include an ACK / NACK for a previous transmission. In some examples, transmitting the message to the base station may include transmitting HARQ feedback in response to the DL transmission. This data may be transmitted on a physical uplink shared channel (PUSCH). UE 415 may report the number of ACKs or NACKs in a multiplexing pattern. In some cases, HARQ feedback may be received for each carrier. In some examples, UE 415 may transmit a bit indicating that at least one transport block in the downlink transmission was successfully decoded. In other examples, UE 415 may transmit a bit indicating that at least one code block in the downlink transmission was successfully decoded. In a further example, UE 415 may transmit a bit indicating a collision that occurred during the transmission at 425.

[0104] At 435, the base station 405 may determine a first parameter associated with the first transmission and may determine a first contention window adjustment value based on the first parameter. In some examples, the first parameter includes HARQ feedback for one or more transmission opportunities. In some examples, the first parameter includes at least one non-reported acknowledgment. In some examples, determining the first parameter includes determining whether the PUCCH has been successfully decoded. Thus, the first parameter may be used by the base station 405 as an indication that a collision may have occurred with another device using a shared spectrum. In other examples, the first parameter is based on a frame structure of the first transmission, wherein in some cases the first transmission is in a licensed spectrum. In some cases, a lookup table may be used to determine the first parameter, wherein the lookup table may be based on the frame structure of the first transmission.

[0105] At 440, the base station 405 may apply a first weighting factor to the first contention window adjustment value. In some examples, the first weighting factor is based at least in part on whether the HARQ feedback is in a multiplexing pattern. (So that the first weighting factor may be based on the number of acknowledgments (ACKs) or NACKs in the multiplexing pattern.) The base station 405 may apply the first weighting factor to the first contention window adjustment value differently for non-reported acknowledgments than for reported NACKs, or may apply the first weighting factor in the same manner. The base station 405 may apply the first weighting factor to the first contention window adjustment value based on the transmission opportunities corresponding to the first contention window adjustment value. In some cases, the first weighting factor is based at least in part on a reported channel quality indicator (CQI), as opposed to a preferred CQI.

[0106] In some examples, applying the first weighting factor to the first contention window adjustment value includes applying a first weighting factor of 0 to the first contention window adjustment value for which the corresponding transmission opportunity falls outside a time period. In some cases, the base station 405 may apply the first weighting factor to the first contention window adjustment value based on an infinite impulse response filter. The base station 405 may apply the first weighting factor to the first contention window adjustment value based on a user equipment (UE) associated with the first parameter.

[0107] The base station 405 may apply a first weighting factor to the first contention window adjustment value based on whether the grant associated with the first parameter can be a valid grant. In some cases, the base station 405 may apply the first weighting factor to the first contention window adjustment value based on the number of supported UEs. In some cases, the base station 405 may apply the first weighting factor to the first contention window adjustment value based on the size of the transmission opportunity or the resource allocation associated with the first parameter. In some cases, the base station 405 may apply the first weighting factor to the first contention window adjustment value based on a block error rate (BLER) associated with the first parameter. In some examples, the first parameter includes an interference indication received in a PUCCH.

[0108] The base station 405 may apply a first weighting factor to the first contention window adjustment value based on a carrier aggregation configuration or a coordinated multi-point configuration. In some cases, the base station 405 may apply the first weighting factor to the first contention window adjustment value based on whether the first parameter corresponds to a broadcast channel. In some cases, the base station 405 may apply the first weighting factor to the first contention window adjustment value based on whether the first parameter corresponds to a UE that implements or is capable of interference cancellation. In some examples, the contention window size corresponds to a DL transmission opportunity that follows one or more DL transmission opportunities corresponding to the first parameter.

[0109] At 445, the base station 405 may determine a contention window size for the second transmission based on the weighted first contention window adjustment value. In some examples, the first contention window adjustment value is based at least in part on the number of NACKs in the HARQ feedback. In some examples, the contention window size is adjusted based at least in part on whether the UL transmission opportunity is self-scheduled or cross-carrier scheduled. In other examples, the contention window size may be adjusted for each carrier, which may be based on the number of NACKs received on each carrier. In other cases, the contention window size may be adjusted for all carriers, where the adjustment depends on the ACK / NACKs received for all carriers.

[0110] In some cases, the base station 405 may determine a second parameter associated with the second transmission and may determine a second contention window adjustment value based at least in part on the second parameter. The base station 405 may apply a second weighting factor to the second contention window adjustment value so that the contention window size is adjusted based at least in part on the weighted second contention window adjustment value.

[0111] In some cases, the contention window size may be reset. This may be based at least in part on the duration of time that has elapsed since the transmission. In other cases, the window size may be reset if the base station 405 receives at least one ACK indication from each of the one or more UEs 415 at 430. In other cases, the window size may be reset if the percentage of ACKs relative to the total number of ACKs and NACKs received is above a threshold. Alternatively, if the number of UEs is greater than a certain threshold, the contention window size may be reset if at least one ACK indication is received from a predetermined percentage of UEs.

[0112] At 450, the base station 405 may perform a clear channel assessment based on the contention window size. In some examples, the base station 405 may not perform CCA but may transmit the contention window size to the UE 415 before the UL transmission opportunity, and the UE 415 may perform CCA based on the window size (e.g., for UL transmission). In some cases, the base station 405 may start a backoff timer, which may be associated with the primary carrier and applicable to all secondary carriers. In some examples, the base station 405 may transmit to multiple UEs 415. In such cases, the base station 405 may divide the one or more UEs 415 into one or more groups based on the contention window size of the one or more UEs 415, randomly generate a counter for the one or more UE 415 groups, and start the counter.

[0113] At 455, base station 405 may transmit to UE 415. In some cases, the transmission at 455 may depend on the expiration of a counter or backoff timer. In some examples, base station 405 may randomly regenerate the counters for one or more groups of UEs 415 after the transmission. In other examples, base station 405 may retain the values ​​of the counters for one or more groups of UEs 415 at the time the transmission at 455 occurs. In other examples, base station 405 may refrain from resetting the contention window size if the transmission at 455 is on a different carrier than the transmission at 425.

[0114] Figure 5 A block diagram of a wireless device 500 supporting CCA window adaptation according to aspects of the present disclosure is shown. The wireless device 500 may be a reference Figure 1-4Examples of aspects of the UE 115 are described. The wireless device 500 may include a receiver 505, a CCA adaptation component 510, or a transmitter 515. The wireless device 500 may also include a processor. Each of these components may be in communication with each other.

[0115] The receiver 505 can receive information, such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to CCA window adaptation, etc.). The information can be passed to the CCA adaptation component 510 and to other components of the wireless device 500.

[0116] The CCA adaptation component 510 can transmit a message to a base station; receive a contention window size from the base station, such that the contention window size is calculated based at least in part on the message using a first weighting factor applied to a first contention window adjustment value; and perform a clear channel assessment based at least in part on the contention window size.

[0117] The transmitter 515 can transmit signals received from other components of the wireless device 500. In some examples, the transmitter 515 can be co-located in a transceiver component with the receiver 505. The transmitter 515 can include a single antenna, or it can include multiple antennas.

[0118] Figure 6 A block diagram of a wireless device 600 supporting CCA window adaptation according to aspects of the present disclosure is shown. The wireless device 600 may be a reference Figure 1-5 1. Examples of aspects of wireless device 500 or UE 115 are described. Wireless device 600 may include a receiver 605, a CCA adaptation component 610, or a transmitter 615. Wireless device 600 may also include a processor. Each of these components may be in communication with each other. CCA adaptation component 610 may also include a message transmission component 620, a CW size messaging component 625, and a CCA component 630.

[0119] The receiver 605 may receive information that may be passed to the CCA adaptation component 610 and other components of the wireless device 600. The CCA adaptation component 610 may perform a reference Figure 5 The transmitter 615 may transmit signals received from other components of the wireless device 600.

[0120] The message transmission component 620 can transmit a message to the base station, such as referring to Figure 2-4In some examples, transmitting the message to the base station includes transmitting HARQ feedback in response to the DL transmission, such that the contention window size can be based at least in part on the HARQ feedback. In some examples, transmitting the message to the base station includes transmitting data on the PUSCH. In some examples, transmitting the message to the base station includes transmitting a bit indicating that at least one transport block in the downlink transmission was successfully decoded, or transmitting a bit indicating that at least one code block in the downlink transmission was successfully decoded, or transmitting a bit indicating that a collision occurred in a previous downlink transmission.

[0121] The CW size messaging component 625 can receive a contention window size from a base station such that the contention window size is calculated based at least in part on the message using a first weighting factor applied to a first contention window adjustment value, as described with reference to Figure 2-4 described.

[0122] The CCA component 630 can perform a clear channel assessment based at least in part on the contention window size, as described with reference to Figure 2-4 described.

[0123] Figure 7 A block diagram 700 illustrates a CCA adaptation component 710 that may be a component of the wireless device 500 or the wireless device 600 for CCA window adaptation according to aspects of the present disclosure. The CCA adaptation component 710 may be a reference to Figure 5-6 Examples of aspects of the CCA adaptation component 510 are described. The CCA adaptation component 710 may include a message transmission component 720, a CW size messaging component 725, and a CCA component 730. Each of these components may perform the following operations: Figure 6 The CCA adaptation component 710 may also include a CW weighting factor component 735 .

[0124] The CW weighting factor component 735 can be configured such that a first weighting factor can be applied to the first contention window adjustment value based at least in part on the transmission opportunity corresponding to the first contention window adjustment value, as described with reference to FIG. Figure 2-4 In some examples, the first weighting factor may be applied to the first contention window adjustment value based at least in part on a carrier aggregation configuration or a coordinated multipoint configuration. In some examples, the first weighting factor may be applied to the first contention window adjustment value based at least in part on a number of supported UEs. In some examples, the first weighting factor may be applied to the first contention window adjustment value based at least in part on an interference cancellation capability.

[0125] In some examples, the first weighting factor may be based at least in part on whether HARQ feedback may be in a multiplexing pattern. The CW weighting factor component 735 may also report the number of ACKs or NACKs in the multiplexing pattern, such that the first weighting factor is based on that number. The CW weighting factor component 735 may also apply the first weighting factor to the first contention window adjustment value for at least one non-reported acknowledgment, distinct from the reported NACK. The CW weighting factor component 735 may also apply the first weighting factor to the first contention window adjustment value based on a transmission opportunity corresponding to the first contention window adjustment value.

[0126] In some examples, applying the first weighting factor to the first contention window adjustment value includes applying a first weighting factor of zero to the first contention window adjustment value for a corresponding transmission opportunity that falls outside a time period. The CW weighting factor component 735 may also apply the first weighting factor to the first contention window adjustment value based on an infinite impulse response filter. The CW weighting factor component 735 may also apply the first weighting factor to the first contention window adjustment value based on a user equipment (UE) associated with the first parameter. The CW weighting factor component 735 may also apply the first weighting factor to the first contention window adjustment value based on whether a grant associated with the first parameter is a valid grant. The CW weighting factor component 735 may also apply the first weighting factor to the first contention window adjustment value based on the number of supported UEs.

[0127] The CW weighting factor component 735 may also apply a first weighting factor to the first contention window adjustment value based on a size of a transmission opportunity or a resource allocation associated with the first parameter. The CW weighting factor component 735 may also apply a first weighting factor to the first contention window adjustment value based on a BLER target associated with the first parameter. The CW weighting factor component 735 may also apply a first weighting factor to the first contention window adjustment value based on a carrier aggregation configuration or a coordinated multipoint configuration. The CW weighting factor component 735 may also apply a first weighting factor to the first contention window adjustment value based on whether the first parameter corresponds to a broadcast channel. The CW weighting factor component 735 may also apply a first weighting factor to the first contention window adjustment value based on whether the first parameter corresponds to a UE that implements or is capable of interference cancellation.

[0128] Figure 8 A block diagram illustrating a system 800 including a UE 115 configured for CCA window adaptation according to aspects of the present disclosure is shown. The system 800 may include a UE 815, which may be a reference Figure 1 、 2 Examples of wireless devices 500, wireless devices 600, or UE 115 described in and 5-7. UE 815 may include a CCA adaptation component 810, which may be a reference Figure 5-78. The UE 815 may also include an ECC component 825. The UE 815 may also include components for two-way voice and data communications, including components for transmitting communications and components for receiving communications. For example, the UE 815 may communicate bidirectionally with one or more base stations 105, such as base station 850-a.

[0129] The UE 815 may be enabled to operate using ECC, as described with reference to Figure 1 For example, UE 815 may operate in a shared or unlicensed spectrum using a variable transmission time interval (TTS) or with a larger number of CCs.

[0130] The UE 815 may also include a processor 805 and memory 816 (including software (SW) 820), a transceiver 835, and one or more antennas 840, each of which may communicate directly or indirectly with one another (e.g., via a bus 845). The transceiver 835 may communicate bidirectionally with one or more networks via the antennas 840 or a wired or wireless link, as described above. For example, the transceiver 835 may communicate bidirectionally with a base station 105 or another UE 115. The transceiver 835 may include a modem to modulate packets and provide the modulated packets to the antennas 840 for transmission, and to demodulate packets received from the antennas 840. Although the UE 815 may include a single antenna 840, the UE 815 may also have multiple antennas 840 capable of concurrently transmitting or receiving multiple wireless transmissions.

[0131] The memory 816 may include random access memory (RAM) and read-only memory (ROM). The memory 816 may store computer-readable, computer-executable software / firmware code 820 including instructions that, when executed, cause the processor 805 to perform the various functions described herein (e.g., CCA window adaptation, etc.). Alternatively, the software / firmware code 820 may not be directly executable by the processor 805, but rather (e.g., when compiled and executed) causes the computer to perform the functions described herein. The processor 805 may include an intelligent hardware device (e.g., a central processing unit (CPU), a microcontroller, an application-specific integrated circuit (ASIC), etc.).

[0132] Figure 9 A block diagram of a wireless device 900 supporting CCA window adaptation according to aspects of the present disclosure is shown. The wireless device 900 may be a reference Figure 1-8 Examples of aspects of the base station 105 are described. The wireless device 900 may include a receiver 905, a base station CCA adaptation component 910, or a transmitter 915. The wireless device 900 may also include a processor. Each of these components may be in communication with each other.

[0133] The receiver 905 can receive information, such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to CCA window adaptation, etc.). The information can be passed to the base station CCA adaptation component 910 and to other components of the wireless device 900.

[0134] The base station CCA adaptation component 910 can determine a first parameter associated with the first transmission, determine a first contention window adjustment value based on the first parameter, apply a first weighting factor to the first contention window adjustment value, and adjust the contention window size for the second transmission based on the weighted first contention window adjustment value.

[0135] The transmitter 915 can transmit signals received from other components of the wireless device 900. In some examples, the transmitter 915 can be co-located in a transceiver component with the receiver 905. The transmitter 915 can include a single antenna, or it can include multiple antennas.

[0136] Figure 10 A block diagram of a wireless device 1000 supporting CCA window adaptation according to aspects of the present disclosure is shown. The wireless device 1000 may be a reference Figure 1-9 10. Examples of aspects of the wireless device 900 or base station 105 are described. The wireless device 1000 may include a receiver 1005, a base station CCA adaptation component 1010, or a transmitter 1015. The wireless device 1000 may also include a processor. Each of these components may be in communication with each other. The base station CCA adaptation component 1010 may also include a transmission parameter component 1020, a CW adjustment parameter component 1025, a BS CW weighting factor component 1030, and a CW adjustment component 1035.

[0137] The receiver 1005 may receive information that may be passed to the base station CCA adaptation component 1010 and other components of the wireless device 1000. The base station CCA adaptation component 1010 may perform a reference Figure 9 The transmitter 1015 may transmit signals received from other components of the wireless device 1000. The transmitter 1015 may also transmit on one or more carriers (e.g., a primary carrier and a secondary carrier). In some cases, the one or more secondary carriers may be within a predetermined frequency separation relative to the primary carrier, may be in an unlicensed information infrastructure radio band, and / or the total number of secondary carriers may be less than a predetermined number. In some cases, the transmitter 1015 may transmit after a counter or backoff timer expires.

[0138] The transmission parameter component 1020 can determine a first parameter associated with the first transmission, such as referring to Figure 2-4described. In some examples, the first parameter includes HARQ feedback for one or more transmission opportunities. In some cases, HARQ feedback is received for each carrier. In some examples, the first parameter includes at least one non-reported acknowledgment. In some examples, determining the first parameter includes determining whether the PUCCH has been successfully decoded. The transmission parameter component 1020 may also determine a second parameter associated with the second transmission. In some examples, the first parameter includes an interference indication received in the PUCCH. In some cases, the first parameter may be based on the frame structure of the first transmission. For example, the transmission parameter component 1020 may determine whether the first transmission is in a licensed spectrum. In some cases, the transmission parameter component 1020 may determine that at least one ACK indication is received from each of the one or more UEs based on the first transmission. In other cases, the transmission parameter component 1020 may determine a percentage of ACKs relative to the total number of ACKs and NACKs, or may determine a percentage of UEs that sent at least one ACK.

[0139] The CW adjustment parameter component 1025 can determine a first contention window adjustment value based on the first parameter, such as referring to Figure 2-4 As described. In some examples, the first contention window adjustment value may be based on the number of NACKs in the HARQ feedback. The CW adjustment parameter component 1025 may also determine the second contention window adjustment value based on the second parameter. In some cases, the CW adjustment parameter component 1025 may use a lookup table to determine the adjustment value, wherein the lookup table may be based on the frame structure of the first transmission. In other cases, the CW adjustment parameter component 1025 may determine the adjustment value based on the number of NACKs received for each carrier. Alternatively, the adjustment value is based on the number of NACKs received for all carriers. In other examples, the CW adjustment parameter component 1025 may determine the first contention window adjustment value based on a reported channel quality indicator (CQI) (as opposed to a preferred CQI).

[0140] The BS CW weighting factor component 1030 can apply a first weighting factor to the first contention window adjustment value, as described with reference to Figure 2-4 described.

[0141] The CW adjustment component 1035 can adjust the contention window size for the second transmission based on the weighted first contention window adjustment value, as shown in FIG. Figure 2-4As described. In some examples, the contention window size corresponds to an UL transmission opportunity. In some examples, the contention window size can be adjusted based on whether the UL transmission opportunity can be self-scheduled or cross-carrier scheduled. The CW adjustment component 1035 can also apply a second weighting factor to the second contention window adjustment value so that the contention window size is adjusted based on the weighted second contention window adjustment value. In some examples, the contention window size corresponds to a DL transmission opportunity that follows one or more DL transmission opportunities corresponding to the first parameter. In addition, the CW adjustment component 1035 can adjust the contention window size independently for each carrier, or can adjust all carriers similarly.

[0142] CW adjustment component 1035 can also reset the contention window size. In some cases, the reset can be based on the duration that has elapsed since the previous transmission. In other cases, the reset can be based on a percentage of ACKs received or based on receiving an ACK from each user, as discussed above. In some cases, if the second transmission is on a different carrier than the first transmission, CW adjustment component 1035 can refrain from resetting the contention window size.

[0143] Figure 11 A block diagram 1100 illustrates a base station CCA adaptation component 910-b that may be a component of the wireless device 900 or the wireless device 1000 for CCA window adaptation according to aspects of the present disclosure. The base station CCA adaptation component 1145 may be a reference to Figure 9-10 Examples of aspects of the base station CCA adaptation component 910 are described. The base station CCA adaptation component 1145 may include a transmission parameter component 1120, a CW adjustment parameter component 1125, a BS CW weighting factor component 1130, and a CW adjustment component 1135. Each of these components may perform the operations described with reference to Figure 10 The base station CCA adaptation component 1145 may also include a BS CW size messaging component 1145 and a BS CCA component 1145 .

[0144] BS CW size messaging component 1140 can communicate the contention window size to the UE prior to an UL transmission opportunity, as described with reference to Figure 2-4 described.

[0145] The BS CCA component 1145 can perform a clear channel assessment based on the contention window size, as described with reference to Figure 2-4 described.

[0146] BS CCA component 1145 may also start a backoff timer. The backoff timer may be applied to the primary carrier and, in some cases, the secondary carrier. BS CCA component 1145 may also divide the one or more UEs into one or more UE groups based on the contention window size of the one or more UEs, randomly generate counters for the one or more groups, and start the counters for the one or more groups. BS CCA component 1145 may stop the counters for the one or more groups based on the expiration of the counter for the UE group whose counter expires first. BS CCA component 1145 may then randomly regenerate the counters for the one or more UE groups or may retain the values ​​of the counters for the one or more groups for subsequent transmissions.

[0147] Figure 12 A block diagram illustrating a system 1200 including a base station 105 supporting CCA window adaptation according to aspects of the present disclosure is shown. The system 1200 may include a base station 1205, which may be a reference Figure 1 、 2 Examples of wireless devices 900, wireless devices 1000, or base stations 105 described in and 9-11. The base station 1205 may include a base station CCA adaptation component 1210, which may be a reference to Figure 9-11 The base station 1205 may also include components for two-way voice and data communications, including components for transmitting communications and components for receiving communications. For example, the base station 1205 may communicate two-way with the UE 1245, which may be Figure 1 Example of UE 115.

[0148] In some cases, base station 1205 may have one or more wired backhaul links. Base station 1205 may have a wired backhaul link (e.g., an S1 interface, etc.) to core network 130. Base station 1205 may also communicate with other base stations 105 (such as base station 1205-a or base station 1205-b) via an inter-base station backhaul link (e.g., an X2 interface). Each base station 1205 may communicate with UE 115 using the same or different wireless communication technologies. In some cases, base station 1205 may utilize base station communication component 1225 to communicate with other base stations. In some examples, base station communication component 1225 may provide an X2 interface within long-term evolution (LTE) / LTE wireless communication technology to provide communication between some base stations 105. In some examples, base station 1205 may communicate with other base stations through core network 130. In some cases, base station 1205 may communicate with core network 130 through network communication component 1230.

[0149] The base station 1205 may include a processor 1206, a memory 1215 (including software (SW) 1220), a transceiver 1235, and an antenna 1240, each of which may communicate directly or indirectly with each other (e.g., via a bus system 1246). The transceiver 1235 may be configured to communicate bidirectionally with the UE 115 (which may be a multi-mode device) via the antenna 1240. The transceiver 1235 (or other components of the base station 1205) may also be configured to communicate bidirectionally with one or more other base stations (not shown) via the antenna 1240. The transceiver 1235 may include a modem configured to modulate packets and provide the modulated packets to the antenna 1240 for transmission, and to demodulate packets received from the antenna 1240. The base station 1205 may include multiple transceivers 1235, each having one or more associated antennas 1240. The transceiver may be Figure 9 An example of a combined receiver 905 and transmitter 915.

[0150] The memory 1215 may include RAM and ROM. The memory 1215 may also store computer-readable, computer-executable software code 1220 containing instructions that are configured to cause the processor 1206 to perform the various functions described herein (e.g., CCA window adaptation, selection of coverage enhancement technology, call processing, database management, message routing, etc.) when executed. Alternatively, the software 1220 may not be directly executable by the processor 1206, but is configured to cause the computer to perform the functions described herein (e.g., when compiled and executed). The processor 1206 may include an intelligent hardware device, such as a CPU, a microcontroller, an ASIC, etc. The processor 1206 may include various special-purpose processors, such as an encoder, a queue processing component, a baseband processor, a radio head controller, a digital signal processor (DSP), etc.

[0151] Base station communication component 1225 can manage communications with other base stations 105. In some cases, the communication management component can include a controller or scheduler for controlling communications with UE 115 in coordination with other base stations 105. For example, base station communication component 1225 can coordinate the scheduling of transmissions to UE 115 for various interference mitigation techniques, such as beamforming or joint transmissions.

[0152] The components of the wireless device 500, wireless device 600, CCA adaptation component 510, UE 815, wireless device 900, BS CCA adaptation component 910, and base station 1205 may be implemented individually or collectively using at least one ASIC adapted to perform some or all applicable functions in hardware. Alternatively, these functions may be performed by one or more other processing units (or cores) on at least one IC. In other examples, other types of integrated circuits (e.g., structured / platform ASICs, field programmable gate arrays (FPGAs), or other semi-custom ICs) that can be programmed in any manner known in the art may be used. The functions of each unit may also be implemented in whole or in part using instructions embodied in a memory and formatted to be executed by one or more general-purpose or application-specific processors.

[0153] Figure 13 A flow chart illustrating a method 1300 for CCA window adaptation according to aspects of the present disclosure is shown. The operations of the method 1300 may be described with reference to Figure 1-12 For example, the operations of method 1300 may be implemented by referring to Figure 5-8 In some examples, the UE 115 may execute a set of codes for controlling the functional elements of the UE 115 to perform the functions described below. Additionally or alternatively, the UE 115 may use dedicated hardware to perform aspects of the functions described below.

[0154] At block 1305, UE 115 may transmit a message to a base station, as described with reference to Figure 2-4 In some examples, transmitting the message to the base station includes transmitting a bit indicating that at least one transport block in the downlink transmission is successfully decoded, or transmitting a bit indicating that at least one code block in the downlink transmission is successfully decoded, or transmitting a bit indicating a collision during the downlink transmission. In some examples, the operation of block 1305 can be as described above with reference to Figure 6 The message transmission component 620 described above is executed.

[0155] At block 1310, the UE 115 may receive a contention window size from the base station such that the contention window size is calculated based on the message using a first weighting factor applied to a first contention window adjustment value, as described with reference to Figure 2-4 In some examples, the operations of block 1310 may be as described above. Figure 6 The CW size messaging component 625 described above is executed.

[0156] At block 1315, UE 115 may perform a clear channel assessment based on the contention window size, as described with reference to Figure 2-4In some examples, the operation of block 1315 may be as described above with reference to Figure 6 The CCA component 630 described above is executed.

[0157] Figure 14 A flow chart illustrating a method 1400 for CCA window adaptation according to aspects of the present disclosure is shown. The operations of the method 1400 may be described with reference to Figure 1-12 For example, the operations of method 1400 may be performed by a base station 105 or a component thereof as described above. Figure 9-12 The base station CCA adaptation component 910 described herein is executed. In some examples, the base station 105 may execute a code set for controlling the functional elements of the base station 105 to perform the functions described below. Additionally or alternatively, the base station 105 may use dedicated hardware to perform aspects of the functions described below. The method 1400 may also incorporate Figure 13 Aspects of method 1300.

[0158] At block 1405, the base station 105 may determine a first parameter associated with the first transmission, such as with reference to Figure 2-4 In some examples, the operation of block 1405 may be as described above. Figure 10 The transmission parameter component 1020 described above is executed.

[0159] At block 1410, the base station 105 may determine a first contention window adjustment value based on a first parameter, as described with reference to Figure 2-4 In some examples, the operations of block 1410 may be as described above. Figure 10 The CW adjustment parameter component 1025 described above is performed.

[0160] At block 1415, the base station 105 may apply a first weighting factor to the first contention window adjustment value, as described with reference to Figure 2-4 In some examples, the operation of block 1415 may be as described above with reference to Figure 10 1030 to perform the BS CW weighting factor component 1030 described herein.

[0161] At block 1420, the base station 105 may adjust the contention window size for the second transmission based on the weighted first contention window adjustment value, as described with reference to FIG. Figure 2-4 In some examples, the operations of block 1420 may be as described above with reference to Figure 10 The CW adjustment component 1035 described above is performed.

[0162] Figure 15 A flow chart illustrating a method 1500 for CCA window adaptation according to aspects of the present disclosure is shown. The operations of the method 1500 may be described with reference to Figure 1-12For example, the operations of method 1500 may be performed by a base station 105 or a component thereof as described above. Figure 9-12 The base station CCA adaptation component 910 described herein is executed. In some examples, the base station 105 may execute a code set for controlling the functional elements of the base station 105 to perform the functions described below. Additionally or alternatively, the base station 105 may use dedicated hardware to perform aspects of the functions described below. The method 1500 may also incorporate Figure 13-14 Aspects of methods 1300 and 1400.

[0163] At block 1505, the base station 105 may determine a first parameter associated with the first transmission, such as with reference to Figure 2-4 In some examples, the operation of block 1505 may be as described above. Figure 10 The transmission parameter component 1020 described above is executed.

[0164] At block 1510, the base station 105 may determine a first contention window adjustment value based on a first parameter, as described with reference to Figure 2-4 In some cases, the first parameter includes HARQ feedback for one or more transmission opportunities. In some examples, the operation of block 1510 may be as described above with reference to Figure 10 The CW adjustment parameter component 1025 described above is performed.

[0165] At block 1515, the base station 105 may apply a first weighting factor to the first contention window adjustment value, as described with reference to Figure 2-4 In some examples, the operation of block 1515 may be as described above with reference to Figure 10 1030 to perform the BS CW weighting factor component 1030 described herein.

[0166] At block 1520, the base station 105 may adjust the contention window size for the second transmission based on the weighted first contention window adjustment value, as described with reference to FIG. Figure 2-4 In some examples, the operations of block 1520 may be as described above. Figure 10 The CW adjustment component 1035 described above is performed.

[0167] Figure 16 A flow chart illustrating a method 1600 for CCA window adaptation according to aspects of the present disclosure is shown. The operations of the method 1600 may be described with reference to Figure 1-12 For example, the operations of method 1600 may be performed by a base station 105 or a component thereof as described above. Figure 9-12The base station CCA adaptation component 910 described herein is executed. In some examples, the base station 105 may execute a code set for controlling the functional elements of the base station 105 to perform the functions described below. Additionally or alternatively, the base station 105 may use dedicated hardware to perform aspects of the functions described below. The method 1600 may also incorporate Figure 13-15 Aspects of methods 1300, 1400, and 1500.

[0168] At block 1605, the base station 105 may determine a first parameter associated with the first transmission, such as with reference to Figure 2-4 In some cases, the first parameter includes at least one non-reported acknowledgement. In some examples, the operation of block 1605 may be as described above with reference to Figure 10 The transmission parameter component 1020 described above is executed.

[0169] At block 1610, the base station 105 may determine a first contention window adjustment value based on a first parameter, as described with reference to Figure 2-4 In some examples, the operations of block 1610 may be as described above. Figure 10 The CW adjustment parameter component 1025 described above is performed.

[0170] At block 1615, the base station 105 may apply a first weighting factor to the first contention window adjustment value, as described with reference to Figure 2-4 In some examples, the operation of block 1615 may be as described above with reference to Figure 10 1030 to perform the BS CW weighting factor component 1030 described herein.

[0171] At block 1620, the base station 105 may adjust the contention window size for the second transmission based on the weighted first contention window adjustment value, as described with reference to FIG. Figure 2-4 In some examples, the operations of block 1620 may be as described above with reference to Figure 10 The CW adjustment component 1035 described above is performed.

[0172] Figure 17 A flow chart illustrating a method 1700 for CCA window adaptation according to aspects of the present disclosure is shown. The operations of the method 1700 may be described with reference to Figure 1-12 For example, the operations of method 1700 may be performed by a base station 105 or a component thereof as described above. Figure 9-12 The base station CCA adaptation component 910 described herein is executed. In some examples, the base station 105 may execute a code set for controlling the functional elements of the base station 105 to perform the functions described below. Additionally or alternatively, the base station 105 may use dedicated hardware to perform aspects of the functions described below. The method 1600 may also incorporate Figure 13-16 Aspects of methods 1300, 1400, 1500 and 1600.

[0173] At block 1705, the base station 105 may determine a first parameter associated with the first transmission, such as with reference to Figure 2-4 In some cases, determining the first parameter includes determining whether the PUCCH has been successfully decoded. In some examples, the operation of block 1705 may be as described above with reference to Figure 10 The transmission parameter component 1020 described above is executed.

[0174] At block 1710, the base station 105 may determine a first contention window adjustment value based on a first parameter, as described with reference to Figure 2-4 In some examples, the operations of block 1710 may be as described above. Figure 10 The CW adjustment parameter component 1025 described above is performed.

[0175] At block 1715, the base station 105 may apply a first weighting factor to the first contention window adjustment value, as described with reference to Figure 2-4 In some examples, the operation of block 1715 may be as described above with reference to Figure 10 1030 to perform the BS CW weighting factor component 1030 described herein.

[0176] At block 1720, the base station 105 may adjust the contention window size for the second transmission based on the weighted first contention window adjustment value, as described with reference to FIG. Figure 2-4 In some cases, the contention window size corresponds to an UL transmission opportunity. In some examples, the operation of block 1720 may be as described above with reference to Figure 10 The CW adjustment component 1035 described above is performed.

[0177] At block 1725, the base station 105 may transmit the contention window size to the UE prior to the UL transmission opportunity, as described with reference to Figure 2-4 In some examples, the operation of block 1725 may be performed by referring to Figure 11 1140 for performing the BS CW size messaging described herein.

[0178] Figure 18 A flow chart illustrating a method 1800 for CCA window adaptation according to aspects of the present disclosure is shown. The operations of the method 1800 may be described with reference to Figure 1-12 For example, the operations of method 1800 may be performed by a base station 105 or a component thereof as described above. Figure 9-12 The base station CCA adaptation component 910 described herein is executed. In some examples, the base station 105 may execute a code set for controlling the functional elements of the base station 105 to perform the functions described below. Additionally or alternatively, the base station 105 may use dedicated hardware to perform aspects of the functions described below. The method 1800 may also incorporate Figure 13-17Aspects of methods 1300, 1400, 1500, 1600 and 1700.

[0179] At block 1805, the base station 105 may determine a first parameter associated with the first transmission, such as with reference to Figure 2-4 In some examples, the operation of block 1805 may be as described above. Figure 10 The transmission parameter component 1020 described above is executed.

[0180] At block 1810, the base station 105 may determine a first contention window adjustment value based on a first parameter, as described with reference to Figure 2-4 In some examples, the operation of block 1810 may be as described above with reference to Figure 10 The CW adjustment parameter component 1025 described above is performed.

[0181] At block 1815, the base station 105 may apply a first weighting factor to the first contention window adjustment value, as described with reference to Figure 2-4 In some examples, the operation of block 1815 may be as described above with reference to Figure 10 1030 to perform the BS CW weighting factor component 1030 described herein.

[0182] At block 1820, the base station 105 may determine a second parameter associated with the second transmission, such as with reference to Figure 2-4 In some examples, the operation of block 1820 may be as described above with reference to Figure 10 The transmission parameter component 1020 described above is executed.

[0183] At block 1825, the base station 105 may determine a second contention window adjustment value based on the second parameter, as described with reference to Figure 2-4 In some examples, the operation of block 1825 may be performed as described with reference to Figure 10 The CW adjustment parameter component 1025 described above is performed.

[0184] At block 1830, the base station 105 may apply a second weighting factor to the second contention window adjustment value such that the contention window size is adjusted based on the weighted second contention window adjustment value, as described with reference to FIG. Figure 2-4 In some examples, the operation of block 1830 may be performed as described with reference to Figure 10 The CW adjustment component 1035 described above is performed.

[0185] At block 1835, the base station 105 may adjust the contention window size for the second transmission based on the weighted first contention window adjustment value, as shown in FIG. Figure 2-4 In some examples, the operation of block 1835 may be performed as described with reference to Figure 10 The CW adjustment component 1035 described above is performed.

[0186] Figure 19 1 is a flow chart illustrating a method 1900 for CCA window adaptation according to aspects of the present disclosure. The operations of the method 1900 may be performed as described with reference to FIG. Figure 1-12 For example, the operations of method 1900 may be performed by a base station 105 or a component thereof as described above. Figure 9-12 The base station CCA adaptation component 910 described herein is executed. In some examples, the base station 105 may execute a code set for controlling the functional elements of the base station 105 to perform the functions described below. Additionally or alternatively, the base station 105 may use dedicated hardware to perform aspects of the functions described below. The method 1900 may also incorporate Figure 13-18 Aspects of methods 1300, 1400, 1500, 1600, 1700 and 1800.

[0187] At block 1905, the base station 105 may determine a first parameter associated with the first transmission, such as with reference to Figure 2-4 In some examples, the operation of block 1905 may be performed as described with reference to Figure 10 The transmission parameter component 1020 described above is executed.

[0188] At block 1910, the base station 105 may determine a first contention window adjustment value based on a first parameter, as described with reference to Figure 2-4 In some examples, the operation of block 1910 may be performed as described with reference to Figure 10 The CW adjustment parameter component 1025 described above is performed.

[0189] At block 1915, the base station 105 may apply a first weighting factor to the first contention window adjustment value, as described with reference to Figure 2-4 In some examples, the operation of block 1915 may be performed as described with reference to Figure 10 1030 to perform the BS CW weighting factor component 1030 described herein.

[0190] At block 1920, the base station 105 may adjust the contention window size for the second transmission based on the weighted first contention window adjustment value, as described with reference to Figure 2-4 In some examples, the operation of block 1920 may be performed as described with reference to Figure 10 The CW adjustment component 1035 described above is performed.

[0191] At block 1925, the base station 105 may perform a clear channel assessment based on the contention window size, as described with reference to Figure 2-4 In some examples, the operation of block 1925 may be performed as described with reference to Figure 6 The CCA component 630 described above is executed.

[0192] Figure 20FIG. 1 is a flow chart illustrating a method 2000 for CCA window adaptation according to aspects of the present disclosure. The operations of the method 2000 may be described with reference to FIG. Figure 1-12 For example, the operations of method 2000 may be performed by the base station 105 or its components as described above. Figure 9-12 The base station CCA adaptation component 910 described herein is executed. In some examples, the base station 105 may execute a code set for controlling the functional elements of the base station 105 to perform the functions described below. Additionally or alternatively, the base station 105 may use dedicated hardware to perform aspects of the functions described below. The method 2000 may also incorporate Figure 13-19 Aspects of methods 1300, 1400, 1500, 1600, 1700, 1800 and 1900.

[0193] At block 2005, the base station 105 may determine first parameters associated with a first transmission, wherein the parameters include HARQ feedback for one or more carriers, as described with reference to Figure 2-4 In some examples, the operation of block 2005 may be performed by referring to Figure 10 The transmission parameter component 1020 described above is executed.

[0194] At block 2010, the base station 105 may determine a first contention window adjustment value based on the HARQ feedback for each carrier, as described with reference to Figure 2-4 In some examples, the operations of block 2010 may be performed as described with reference to Figure 10 The CW adjustment parameter component 1025 described above is performed.

[0195] At block 2015, the base station 105 may apply a first weighting factor to the first contention window adjustment value, as described with reference to Figure 2-4 In some examples, the operation of block 2015 may be performed as described with reference to Figure 10 1030 to perform the BS CW weighting factor component 1030 described herein.

[0196] At block 2020, the base station 105 may adjust the contention window size for each carrier for the second transmission based on the weighted first contention window adjustment value, as described with reference to Figure 2-4 In some examples, the operations of block 2020 may be performed as described with reference to Figure 10 The CW adjustment component 1035 described above is performed.

[0197] Figure 21 A flow chart illustrating a method 2100 for CCA window adaptation according to aspects of the present disclosure is shown. The operations of the method 2100 may be described with reference to Figure 1-12 For example, the operations of method 2100 may be performed by a base station 105 or a component thereof as described above. Figure 9-12The base station CCA adaptation component 910 described herein is executed. In some examples, the base station 105 may execute a code set for controlling the functional elements of the base station 105 to perform the functions described below. Additionally or alternatively, the base station 105 may use dedicated hardware to perform aspects of the functions described below. The method 2100 may also incorporate Figure 13-20 Aspects of methods 1300, 1400, 1500, 1600, 1700, 1800, 1900 and 2000.

[0198] At block 2105, the base station 105 may determine a first parameter associated with the first transmission, wherein the parameter includes an ACK or NACK indication from each UE served by the base station, as described with reference to Figure 2-4 In some examples, the operation of block 2105 may be performed as described with reference to Figure 10 The transmission parameter component 1020 described above is executed.

[0199] At block 2110, the base station 105 may determine that an ACK is received from each UE served by the base station, as described with reference to FIG. Figure 2-4 In some examples, the operation of block 2110 may be performed as described with reference to Figure 10 The CW adjustment parameter component 1025 described above is performed.

[0200] At block 2115, the base station 105 may reset the contention window size, as described with reference to Figure 2-4 In some examples, the operation of block 2115 may be performed as described with reference to Figure 10 The CW adjustment component 1035 described above is performed.

[0201] Thus, methods 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, and 2100 can provide for CCA window adaptation. It should be noted that methods 1300, 1400, 1500, 1600, 1700, 1800, and 1900 describe possible implementations, and these operations and steps can be rearranged or otherwise modified to make other implementations possible. In some examples, aspects of two or more of methods 1300, 1400, 1500, 1600, 1700, 1800, and 1900 can be combined.

[0202] The description herein provides examples and does not limit the scope, applicability, or examples set forth in the claims. The functions and arrangements of the elements discussed may be changed without departing from the scope of this disclosure. Various examples may appropriately omit, substitute, or add various procedures or components. In addition, features described with reference to some examples may be combined in other examples.

[0203] The techniques described herein can be used in various wireless communication systems, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), and other systems. The terms "system" and "network" are often used interchangeably. A code division multiple access (CDMA) system can implement radio technologies such as CDMA2000 and Universal Terrestrial Radio Access (UTRA). CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000 versions 0 and A are often referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is often referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other CDMA variants. A time division multiple access (TDMA) system can implement radio access technologies such as Global System for Mobile Communications (GSM). Orthogonal Frequency Division Multiple Access (OFDMA) systems can implement radio technologies such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, and Flash-OFDM. UTRA and E-UTRA are parts of the Universal Mobile Telecommunications System (UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE) are new versions of the Universal Mobile Telecommunications System (UMTS) that use E-UTRA. UTRA, E-UTRA, the Universal Mobile Telecommunications System (UMTS), LTE, LTE, and Global System for Mobile Communications (GSM) are described in documents from an organization called the 3rd Generation Partnership Project (3GPP). CDMA2000 and UMB are described in documents from an organization called the 3rd Generation Partnership Project 2 (3GPP2). The techniques described herein may be used for the systems and radio technologies mentioned above as well as for other systems and radio technologies. However, the description herein describes an LTE system for example purposes, and LTE terminology is used in much of the description above, but the techniques may also be applicable to applications other than LTE applications.

[0204] In LTE / LTE networks (including such networks described herein), the term evolved Node B (eNB) may be used, for example, to describe a base station. One or more wireless communication systems described herein may include heterogeneous LTE / LTE networks in which different types of evolved Node Bs (eNBs) provide coverage for various geographic regions. For example, each eNB or base station may provide communication coverage for a macro cell, a small cell, or other types of cells. Depending on the context, the term "cell" is a 3GPP term that may be used to describe a base station, a carrier or component carrier associated with a base station, or a coverage area (e.g., a sector, etc.) of a carrier or base station.

[0205] A base station may include or may be referred to by those skilled in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a Node B, an evolved Node B (eNB), a Home Node B, a Home evolved Node B, or some other suitable term. The geographic coverage area of ​​a base station may be divided into sectors that constitute only a portion of the coverage area. One or more wireless communication systems described herein may include different types of base stations (e.g., macro base stations or small cell base stations). The UEs described herein may be able to communicate with various types of base stations and network equipment (including macro eNBs, small cell eNBs, relay base stations, etc.). There may be overlapping geographic coverage areas of different technologies.

[0206] A macro cell generally covers a relatively large geographic area (e.g., an area with a radius of several kilometers) and may allow unrestricted access by UEs with service subscriptions with a network provider. In contrast to a macro cell, a small cell is a low-power base station that may operate in the same or different frequency bands (e.g., licensed, unlicensed, etc.) as the macro cell. According to various examples, small cells may include pico cells, femto cells, and micro cells. A pico cell, for example, may cover a smaller geographic area and may allow unrestricted access by UEs with service subscriptions with a network provider. A femto cell may also cover a smaller geographic area (e.g., a residence) and may provide restricted access by UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs of users in the residence, etc.). An eNB for a macro cell may be referred to as a macro eNB. An eNB for a small cell may be referred to as a small cell eNB, a pico eNB, a femto eNB, or a home eNB. An eNB may support one or more (e.g., two, three, four, etc.) cells (e.g., component carriers). A UE may be able to communicate with various types of base stations and network equipment, including macro eNBs, small cell eNBs, relay base stations, etc.

[0207] One or more wireless communication systems described herein may support synchronous or asynchronous operation. For synchronous operation, base stations may have similar frame timing, and transmissions from different base stations may be approximately aligned in time. For asynchronous operation, base stations may have different frame timing, and transmissions from different base stations may not be aligned in time. The techniques described herein may be used for either synchronous or asynchronous operation.

[0208] Downlink transmissions described herein may also be referred to as forward link transmissions, and uplink transmissions may also be referred to as reverse link transmissions. Each communication link described herein—for example, including Figure 1 and 2 The wireless communication system 100 and wireless communication subsystem 200 may include one or more carriers, where each carrier may be a signal composed of multiple subcarriers (e.g., waveform signals of different frequencies). Each modulated signal may be sent on a different subcarrier and may carry control information (e.g., reference signals, control channels, etc.), overhead information, user data, etc. The communication links described herein (e.g., Figure 1 The communication link 125 may use frequency division duplex (FDD) (e.g., using paired spectrum resources) or time division duplex (TDD) operation (e.g., using unpaired spectrum resources) to transmit bidirectional communications. A frame structure for frequency division duplex (FDD) (e.g., frame structure type 1) and a frame structure for TDD (e.g., frame structure type 2) may be defined.

[0209] The description set forth herein in conjunction with the accompanying drawings describes example configurations and does not represent all examples that can be implemented or fall within the scope of the claims. The term "exemplary" as used herein means "serving as an example, instance, or illustration" and does not mean "better than" or "better than other examples." This detailed description includes specific details to provide an understanding of the described techniques. However, these techniques can be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0210] In the accompanying drawings, similar components or features may have the same reference number. In addition, components of the same type may be distinguished by following the reference number with a dash and a second reference number that distinguishes between the similar components. If only the first reference number is used in the specification, the description applies to any of the similar components having the same first reference number, regardless of the second reference number.

[0211] The information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0212] The various illustrative blocks and components described in conjunction with the disclosure herein may be implemented or executed with a general purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a digital signal processor (DSP) and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

[0213] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, each function may be stored on or transmitted by a computer-readable medium as one or more instructions or codes. Other examples and implementations fall within the scope of this disclosure and the appended claims. For example, due to the nature of software, the functions described above may be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination thereof. Features that implement the functions may also be physically located in various locations, including being distributed so that parts of the functions are implemented at different physical locations. In addition, as used herein (including in the claims), "or" used in an enumeration of items (e.g., an enumeration of items with a phrase such as "at least one of" or "one or more of") indicates an inclusive enumeration, such that, for example, an enumeration of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C).

[0214] Computer-readable media includes both non-transient computer storage media and communication media, and it includes any medium that facilitates a computer program to be transferred from one place to another. Non-transient storage media can be any available medium that can be accessed by a general or special-purpose computer. As an example and not as a limitation, non-transient computer-readable media can include RAM, ROM, electrically erasable programmable read-only memory (EEPROM), compact disc (CD), ROM or other optical disc storage, disk storage or other magnetic storage device, or can be used to carry or store the desired program code means of instruction or data structure form and can be accessed by a general or special-purpose computer or a general or special-purpose processor. Any connection is also properly referred to as computer-readable media. For example, if software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwaves, then the coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwaves are included in the definition of medium. Disk and disc, as used herein, include CDs, laser discs, optical discs, digital versatile discs (DVDs), floppy disks, and Blu-ray discs, where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

[0215] The description herein is provided to enable those skilled in the art to make or use the present disclosure. Various modifications to the present disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the scope of the present disclosure. Thus, the present disclosure is not limited to the examples and designs described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for wireless communication, comprising: determining a feedback parameter associated with the 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 applying a weighting factor to the contention window adjustment value for at least one non-reported acknowledgment in the same manner as for a reported negative acknowledgment; and A contention window size for a second transmission is adjusted based at least in part on the contention window adjustment value.

2. The method of claim 1 , wherein determining the contention window adjustment value comprises weighting the HARQ feedback based at least in part on whether the HARQ feedback is in a multiplexing pattern.

3. The method of claim 1 , wherein determining the contention window adjustment value comprises weighting the identified discontinuous transmission (DTX) as a reported negative acknowledgement (NACK).

4. The method of claim 1, wherein: determining the contention window adjustment value based at least in part on feedback parameters for a plurality of carriers; and Adjusting the contention window size includes adjusting the contention window size for all carriers in the plurality of carriers.

5. The method of claim 1, wherein the feedback parameter comprises hybrid automatic repeat request (HARQ) feedback for one or more transmission opportunities.

6. The method of claim 5, wherein determining the contention window adjustment value is based at least in part on a number of negative acknowledgements (NACKs) in the HARQ feedback.

7. The method of claim 1 , wherein determining the feedback parameter comprises: It is determined whether a physical uplink control channel (PUCCH) has been successfully decoded.

8. 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.

9. The method of claim 1, further comprising: The first transmission is transmitted on one or more carriers.

10. The method of claim 9, wherein the first transmission is transmitted on multiple carriers, the method further comprising: A different contention window size is determined for each of the plurality of carriers.

11. The method of claim 9, wherein the first transmission is transmitted on multiple carriers, the method further comprising: a number of negative acknowledgements (NACKs) received via hybrid automatic repeat request (HARQ) feedback for each of the plurality of carriers; as well as The contention window size for the second transmission is adjusted for all carriers in the plurality of carriers based at least in part on a number of NACKs for all carriers in the plurality of carriers, wherein the contention window size is the same for all carriers in the plurality of carriers.

12. The method of claim 9, wherein the one or more carriers include a primary carrier and one or more secondary carriers, the method further comprising: A backoff timer associated with the primary carrier is started, wherein the backoff timer applies to the one or more secondary carriers.

13. The method of claim 1, further comprising: A clear channel assessment is performed based at least in part on the contention window size.

14. The method of claim 1, further comprising: transmitting the second transmission on a carrier different from a carrier of the first transmission; as well as Inhibit resetting the contention window size.

15. The method of claim 1 , wherein the first transmission is sent to one or more UEs, the method further comprising: Reset the contention window size.

16. The method of claim 1, wherein the feedback parameter comprises an interference indication received in a PUCCH.

17. The method of claim 1, wherein the contention window size corresponds to a DL transmission opportunity following one or more DL transmission opportunities corresponding to the feedback parameter.

18. An apparatus for wireless communication, comprising: processor; a memory in electronic communication with the processor; as well as The processor and the memory are configured to: determining a feedback parameter associated with the first transmission; determining a contention window adjustment value based at least in part on the feedback parameter, wherein determining the contention window adjustment value applies a weighting factor to the contention window adjustment value for at least one non-reported acknowledgment in the same manner as a reported negative acknowledgment; and A contention window size for a second transmission is adjusted based at least in part on the contention window adjustment value.

19. The apparatus of claim 18, wherein determining the contention window adjustment value comprises weighting the HARQ feedback based at least in part on whether the HARQ feedback is in a multiplexing pattern.

20. The apparatus of claim 18, wherein determining the contention window adjustment value comprises weighting the identified discontinuous transmission (DTX) as a reported negative acknowledgement (NACK).

21. The apparatus of claim 18, wherein: determining the contention window adjustment value based at least in part on feedback parameters for a plurality of carriers; and Adjusting the contention window size includes adjusting the contention window size for all carriers in the plurality of carriers.

22. The apparatus of claim 18, wherein the feedback parameters comprise hybrid automatic repeat request (HARQ) feedback for one or more transmission opportunities.

23. The apparatus of claim 22, wherein determining the contention window adjustment value is based at least in part on a number of negative acknowledgements (NACKs) in the HARQ feedback.

24. The apparatus of claim 18, wherein to determine the feedback parameter, the processor and the memory are configured to: It is determined whether a physical uplink control channel (PUCCH) has been successfully decoded.

25. 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.

26. The apparatus of claim 18, wherein the processor and memory are configured to: The first transmission is transmitted on one or more carriers.

27. The apparatus of claim 26, wherein the processor and memory are configured to: transmitting the first transmission on a plurality of carriers; and A different contention window size is determined for each of the plurality of carriers.

28. The apparatus of claim 26, wherein the processor and memory are configured to: transmitting the first transmission on a plurality of carriers; a number of negative acknowledgements (NACKs) received via hybrid automatic repeat request (HARQ) feedback for each of the plurality of carriers; and The contention window size for the second transmission is adjusted for all carriers in the plurality of carriers based at least in part on a number of NACKs for all carriers in the plurality of carriers, wherein the contention window size is the same for all carriers in the plurality of carriers.

29. The apparatus of claim 26, wherein the one or more carriers include a primary carrier and one or more secondary carriers, and the processor and memory are configured to: A backoff timer associated with the primary carrier is started, wherein the backoff timer applies to the one or more secondary carriers.

30. The apparatus of claim 18, wherein the processor and memory are configured to: A clear channel assessment is performed based at least in part on the contention window size.

31. The apparatus of claim 18, wherein the processor and memory are configured to: transmitting the second transmission on a different carrier than the first transmission; and Inhibit resetting the contention window size.

32. 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.

33. The apparatus of claim 18, wherein the feedback parameter comprises an interference indication received in a PUCCH.

34. The apparatus of claim 18, wherein the contention window size corresponds to a DL transmission opportunity following one or more DL transmission opportunities corresponding to the feedback parameter.

35. A device for wireless communication, comprising: means for determining a feedback parameter associated with the 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 applying a weighting factor to the contention window adjustment value for at least one non-reported acknowledgment in the same manner as for a reported negative acknowledgment; as well as Means for adjusting a contention window size for a second transmission based at least in part on the contention window adjustment value.

36. A non-transitory computer-readable medium storing computer-executable code for wireless communication, the code being executable by a processor to: determining a feedback parameter associated with the 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 applying a weighting factor to the contention window adjustment value for at least one non-reported acknowledgment in the same manner as for a reported negative acknowledgment; and A contention window size for a second transmission is adjusted based at least in part on the contention window adjustment value.

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