Patent Publication Number: US-11647496-B2

Title: Autonomous uplink transmission techniques using shared radio frequency spectrum

Description:
CROSS REFERENCES 
     The present Application for Patent is a Divisional of U.S. patent application Ser. No. 15/887,277 by Yerramalli et al., entitled “Autonomous Uplink Transmission Techniques Using Shared Radio Frequency Spectrum” filed Feb. 2, 2018, which claims priority to U.S. Provisional Patent Application No. 62/455,469 by Yerramalli, et al., entitled “Autonomous Uplink Transmission Techniques Using Shared Radio Frequency Spectrum,” filed Feb. 6, 2017, assigned to the assignee hereof. 
    
    
     BACKGROUND 
     The following relates generally to wireless communication, and more specifically to autonomous uplink transmission techniques using shared radio frequency spectrum. 
     Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the 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., a Long Term Evolution (LTE) system, or a New Radio (NR) system). A wireless multiple-access communications system may include a number of base stations or access network nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE). 
     Some wireless systems may enable communication between a base station and a UE over shared or unlicensed radio frequency spectrum bands, or over different radio frequency spectrum bands (e.g., licensed radio frequency spectrum bands and unlicensed radio frequency spectrum bands). When using a shared or unlicensed radio frequency spectrum band, transmitters (e.g., UEs, base stations, or other network access devices) may perform contention-based channel access (e.g., by performing a listen before talk (LBT)  procedure) according to contention-based rules that provide for fair channel access to transmitters that wish to use the shared radio frequency spectrum band. 
     In some cases, a base station may schedule UEs for uplink communications through an assignment or grant of resources. In some cases, a base station may configure a UE to autonomously transmit uplink communications according to an autonomous uplink configuration. In such cases, the base station may not be aware of particular timings for uplink transmissions, due to the autonomous nature of such transmissions and due to the contention-based access to the shared radio frequency spectrum band. 
     SUMMARY 
     The described techniques relate to improved methods, systems, devices, or apparatuses that support autonomous uplink transmissions using shared radio frequency spectrum. Generally, the described techniques provide for efficient coordination of autonomous uplink transmissions, and various associated downlink transmissions. For example, a user equipment (UE) may have data that is to be transmitted according to an autonomous uplink configuration, and may determine a duration of the associated uplink transmission. The UE may modify an uplink waveform or provide an indication to a base station of one or more channel resources that may be available for base station transmissions, in order to more fully utilize shared radio frequency spectrum band resources within a maximum channel occupancy time (MCOT). In some cases, a base station may configure a UE to perform autonomous uplink transmissions, and may activate or deactivate autonomous uplink transmissions based on various factors (e.g., channel conditions, traffic at the base station, etc.) through downlink control information transmitted to the UE. In some cases, the UE and base station may exchange various control information to provide relatively efficient autonomous uplink transmissions and use of the shared radio frequency spectrum band resources. 
     A method of wireless communication is described. The method may include contending for access to a channel of a shared radio frequency spectrum band in accordance with an autonomous uplink configuration which indicates a transmission window available for autonomous uplink transmissions, determining one or more channel access parameters based at least in part on one or more of a duration of an uplink transmission to be transmitted over the channel of the shared radio frequency spectrum band or a TA for the uplink transmission, and transmitting the uplink transmission over the channel of the shared radio  frequency spectrum band in accordance with the autonomous uplink configuration, wherein the uplink transmission indicates one or more of the channel access parameters. 
     An apparatus for wireless communication is described. The apparatus may include means for contending for access to a channel of a shared radio frequency spectrum band in accordance with an autonomous uplink configuration which indicates a transmission window available for autonomous uplink transmissions, means for determining one or more channel access parameters based at least in part on one or more of a duration of an uplink transmission to be transmitted over the channel of the shared radio frequency spectrum band or a TA for the uplink transmission, and means for transmitting the uplink transmission over the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration, wherein the uplink transmission indicates one or more of the channel access parameters. 
     Another apparatus for wireless communication is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be operable to cause the processor to contend for access to a channel of a shared radio frequency spectrum band in accordance with an autonomous uplink configuration which indicates a transmission window available for autonomous uplink transmissions, determine one or more channel access parameters based at least in part on one or more of a duration of an uplink transmission to be transmitted over the channel of the shared radio frequency spectrum band or a TA for the uplink transmission, and transmit the uplink transmission over the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration, wherein the uplink transmission indicates one or more of the channel access parameters. 
     A non-transitory computer readable medium for wireless communication is described. The non-transitory computer-readable medium may include instructions operable to cause a processor to contend for access to a channel of a shared radio frequency spectrum band in accordance with an autonomous uplink configuration which indicates a transmission window available for autonomous uplink transmissions, determine one or more channel access parameters based at least in part on one or more of a duration of an uplink transmission to be transmitted over the channel of the shared radio frequency spectrum band or a TA for the uplink transmission, and transmit the uplink transmission over the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink  configuration, wherein the uplink transmission indicates one or more of the channel access parameters. 
     In some examples of the method, apparatus, and non-transitory computer-readable medium described above, a maximum channel occupancy time (MCOT) for the uplink transmission may be identified, and a difference between the MCOT and the duration of the uplink transmission may be determined, and the difference between the MCOT and the duration of the uplink transmission may be indicated in the uplink transmission. In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the difference between the MCOT and the duration of the uplink transmission may be indicated in the channel access parameters as a number of subframes available for use by one or more other transmitters. 
     Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for modifying a waveform of the uplink transmission based at least in part on the TA. In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the modifying the waveform may include formatting data to be transmitted into the uplink transmission, identifying a timing for starting a subsequent downlink transmission following the uplink transmission and a maximum time gap between the uplink transmission and the subsequent downlink transmission, determining a difference between the maximum time gap and the TA, and puncturing a last symbol of the uplink transmission for a duration of the difference between the maximum time gap and the TA. 
     In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the modifying the waveform may include formatting data to be transmitted into the uplink transmission, identifying a timing for starting a subsequent downlink transmission following the uplink transmission and a maximum time gap between the uplink transmission and the subsequent downlink transmission, determining a time difference between an end of a last symbol of the uplink transmission and the maximum time gap, and cyclically extending samples of the last symbol of the uplink transmission to extend for a duration of the difference between the maximum time gap and the TA. 
     In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the one or more channel access parameters may be determined by determining that the TA exceeds a maximum time gap between the uplink transmission and a  subsequent downlink transmission, and indicating the TA in the uplink transmission to allow another transmitter to transmit a reservation signal for at least a portion of the TA. 
     Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for identifying uplink control information (UCI) associated with the uplink transmission, and transmitting the UCI in a symbol of the uplink transmission before a last symbol of the uplink transmission. 
     Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for identifying a time for starting a subsequent downlink transmission following the uplink transmission, and formatting the uplink transmission to occupy the channel of the shared radio frequency spectrum band until the time for starting the subsequent downlink transmission, where a transmitter of the subsequent downlink transmission performs a CCA to occupy a maximum time gap between the uplink transmission and the subsequent downlink transmission. 
     Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for transmitting a time difference between a MCOT and a duration of the uplink transmission to a base station, where the base station may transmit one or more transmissions during the time difference and one or more other transmitters may be precluded from transmitting during the time difference. 
     Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for determining that additional data may be to be transmitted following the transmission window, and transmitting one or more subsequent uplink transmissions after the uplink transmission outside of the transmission window when a MCOT may be determined as part of the contending for access to the channel of the shared radio frequency spectrum band. In some examples of the method, apparatus, and non-transitory computer-readable medium described above, a first subframe of a first subsequent uplink transmission of the one or more subsequent uplink transmissions includes control channel information that provides information on the one or more subsequent uplink transmissions.  
     A method of wireless communication is described. The method may include receiving RRC signaling including an autonomous uplink configuration for unscheduled autonomous uplink transmissions in a shared radio frequency spectrum band, receiving DCI that activates autonomous uplink transmissions, contending for access to a channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration, and transmitting one or more autonomous uplink transmissions over the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration. 
     An apparatus for wireless communication is described. The apparatus may include means for receiving RRC signaling including an autonomous uplink configuration for unscheduled autonomous uplink transmissions in a shared radio frequency spectrum band, means for receiving DCI that activates autonomous uplink transmissions, means for contending for access to a channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration, and means for transmitting one or more autonomous uplink transmissions over the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration. 
     Another apparatus for wireless communication is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be operable to cause the processor to receive RRC signaling including an autonomous uplink configuration for unscheduled autonomous uplink transmissions in a shared radio frequency spectrum band, receive DCI that activates autonomous uplink transmissions, contend for access to a channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration, and transmit one or more autonomous uplink transmissions over the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration. 
     A non-transitory computer readable medium for wireless communication is described. The non-transitory computer-readable medium may include instructions operable to cause a processor to receive RRC signaling including an autonomous uplink configuration for unscheduled autonomous uplink transmissions in a shared radio frequency spectrum band, receive DCI that activates autonomous uplink transmissions, contend for access to a channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration, and transmit one or more autonomous uplink transmissions over the channel of  the shared radio frequency spectrum band in accordance with the autonomous uplink configuration. 
     Some examples of the method, apparatus, and non-transitory computer-readable medium described above may further include processes, features, means, or instructions for receiving subsequent DCI that deactivates autonomous uplink transmissions, and discontinuing contending for access to the channel of the shared radio frequency spectrum band responsive to the receiving the subsequent DCI that deactivates autonomous uplink transmissions. 
     In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the DCI comprises a CRC field scrambled with an identifier, and a value of the identifier indicates that the DCI is associated with autonomous uplink transmissions. 
     In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the autonomous uplink configuration enables autonomous uplink transmissions on one or more transmit antennas according to a MIMO configuration. 
     A method of wireless communication is described. The method may include identifying an autonomous uplink configuration for unscheduled uplink transmissions in a shared radio frequency spectrum band, contending for access to a channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration, determining uplink control information and uplink shared channel information for an uplink transmission to be transmitted over the channel of the shared radio frequency spectrum band, rating matching the uplink shared channel information around the uplink control information in the uplink transmission, and transmitting the uplink transmission over the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration. 
     An apparatus for wireless communication is described. The apparatus may include means for identifying an autonomous uplink configuration for unscheduled uplink transmissions in a shared radio frequency spectrum band, means for contending for access to a channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration, means for determining uplink control information and uplink shared channel information for an uplink transmission to be transmitted over the channel of the shared radio frequency spectrum band, means for rating matching the uplink shared channel  information around the uplink control information in the uplink transmission, and means for transmitting the uplink transmission over the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration. 
     Another apparatus for wireless communication is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be operable to cause the processor to identify an autonomous uplink configuration for unscheduled uplink transmissions in a shared radio frequency spectrum band, contend for access to a channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration, determine uplink control information and uplink shared channel information for an uplink transmission to be transmitted over the channel of the shared radio frequency spectrum band, rate matching the uplink shared channel information around the uplink control information in the uplink transmission, and transmit the uplink transmission over the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration. 
     A non-transitory computer readable medium for wireless communication is described. The non-transitory computer-readable medium may include instructions operable to cause a processor to identify an autonomous uplink configuration for unscheduled uplink transmissions in a shared radio frequency spectrum band, contend for access to a channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration, determine uplink control information and uplink shared channel information for an uplink transmission to be transmitted over the channel of the shared radio frequency spectrum band, rate matching the uplink shared channel information around the uplink control information in the uplink transmission, and transmit the uplink transmission over the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration. 
     In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the resources used for the uplink control information and rate matching of the shared channel information may be configured in the autonomous uplink configuration. 
     In some examples of the method, apparatus, and non-transitory computer-readable medium described above, a payload size of the uplink control information may be a fixed size configured in the autonomous uplink configuration. In some examples of the method,  apparatus, and non-transitory computer-readable medium described above, the payload size may be independent of a number of subframes of the uplink transmission. 
     In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the uplink control information comprises one or more of a HARQ identification, a burst length of the uplink transmission, a MCOT, a RV indication, a NDI, or a UE identifier. In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the uplink control information comprises a time difference between a maximum channel occupancy time (MCOT) and a duration of a burst length of the uplink transmission. 
     A method of wireless communication is described. The method may include identifying an autonomous uplink configuration for unscheduled uplink transmissions in a shared radio frequency spectrum band, receiving A-DCI associated with one or more autonomous uplink transmissions, and transmitting an autonomous uplink transmission over the shared radio frequency spectrum band in accordance with the autonomous uplink configuration and the A-DCI. 
     An apparatus for wireless communication is described. The apparatus may include means for identifying an autonomous uplink configuration for unscheduled uplink transmissions in a shared radio frequency spectrum band, means for receiving A-DCI associated with one or more autonomous uplink transmissions, and means for transmitting an autonomous uplink transmission over the shared radio frequency spectrum band in accordance with the autonomous uplink configuration and the A-DCI. 
     Another apparatus for wireless communication is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be operable to cause the processor to identify an autonomous uplink configuration for unscheduled uplink transmissions in a shared radio frequency spectrum band, receive A-DCI associated with one or more autonomous uplink transmissions, and transmit an autonomous uplink transmission over the shared radio frequency spectrum band in accordance with the autonomous uplink configuration and the A-DCI. 
     A non-transitory computer readable medium for wireless communication is described. The non-transitory computer-readable medium may include instructions operable to cause a processor to identify an autonomous uplink configuration for unscheduled uplink  transmissions in a shared radio frequency spectrum band, receive A-DCI associated with one or more autonomous uplink transmissions, and transmit an autonomous uplink transmission over the shared radio frequency spectrum band in accordance with the autonomous uplink configuration and the A-DCI. 
     In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the A-DCI comprises a bitmap of feedback information associated with one or more feedback processes associated with one or more autonomous uplink transmission. In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the feedback information comprises one or more ACK/NACK indications for one or more HARQ processes. In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the bits from two or more feedback processes may be bundled. 
     In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the A-DCI may include uplink power control information for one or more autonomous uplink transmission. In some examples, a medium access control (MAC) control element (CE) may include the uplink power control information for one or more autonomous uplink transmission and be transmitted over a shared channel transmission. In some examples of the method, apparatus, and non-transitory computer-readable medium described above, the MAC-CE includes a CQI or a MCS indicator, and an acknowledgment may be transmitted that the CQI or MCS are successfully received. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    illustrates an example of a system for wireless communication that supports autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with aspects of the present disclosure. 
         FIG.  2    illustrates an example of a wireless communications system that supports autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with aspects of the present disclosure. 
         FIG.  3    illustrates an example of shared channel resources that supports autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with aspects of the present disclosure.  
         FIG.  4    illustrates an example of a process flow that supports autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with aspects of the present disclosure. 
         FIG.  5    illustrates an example of another process flow that supports autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with aspects of the present disclosure. 
         FIG.  6    illustrates an example of another process flow that supports autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with aspects of the present disclosure. 
         FIG.  7    illustrates an example of another process flow that supports autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with aspects of the present disclosure. 
         FIGS.  8  through  10    show block diagrams of a device that supports autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with aspects of the present disclosure. 
         FIG.  11    illustrates a block diagram of a system including a user equipment (UE) that supports autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with aspects of the present disclosure. 
         FIGS.  12  through  14    show block diagrams of a device that supports autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with aspects of the present disclosure. 
         FIG.  15    illustrates a block diagram of a system including a base station that supports autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with aspects of the present disclosure. 
         FIGS.  16  through  25    illustrate methods for autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION  
     The described techniques relate to improved methods, systems, devices, or apparatuses that support autonomous uplink transmissions using shared or unlicensed radio frequency spectrum. Generally, the described techniques provide for efficient coordination of autonomous uplink transmissions, and associated downlink transmissions through various signals, control information, waveform modification, or combinations thereof. 
     In some examples, unlicensed radio frequency spectrum bands may be used for Long Term Evolution (LTE) or LTE-Advanced (LTE-A) communications. Unlicensed radio frequency spectrum may be used in combination with, or independent from, a dedicated or licensed radio frequency spectrum band. The dedicated radio frequency spectrum band may include a radio frequency spectrum band licensed to particular users for particular uses. The unlicensed or shared radio frequency spectrum band may include a radio frequency spectrum band available for Wi-Fi use, a radio frequency spectrum band available for use by different radio access technologies, or a radio frequency spectrum band available for use by multiple mobile network operators (MNOs) in an equally shared or prioritized manner. The terms unlicensed radio frequency spectrum and shared radio frequency spectrum are used interchangeably herein. 
     Wireless communications systems that support autonomous uplink coordination using shared radio frequency spectrum may use a listen-before-talk (LBT) procedure to resolve user equipment (UE) ambiguity and to mitigate potential for collisions that may arise in scenarios where un-scheduled wireless systems coexist with scheduled wireless systems (such as a MuLTEfire system). In the LBT procedure according to an autonomous uplink transmission configuration, a UE may monitor a medium for a defined time period to detect activity from other intra-cell UEs. If the UE does not detect any activity during the LBT procedure (e.g., a clear channel assessment), the UE may transmit a busy signal until the next subframe, and may begin transmitting uplink data (e.g., using a physical uplink shared channel (PUSCH)) multiplexed with or shortly after an autonomous physical uplink control channel (A-PUCCH) transmission. 
     In some examples, a UE may have data that is to be transmitted according to an autonomous uplink (AUL) configuration, and may determine a duration of the associated uplink transmission. Upon performing channel contention and gaining access to the shared radio frequency spectrum band, the UE may modify an uplink waveform or provide an indication to a base station of one or more channel resources that may be available for base  station transmissions, in order to more fully utilize shared radio frequency spectrum band resources within a maximum channel occupancy time (MCOT). In some cases, a base station may configure a UE to perform AUL transmissions, and may activate or deactivate AUL transmissions based on various factors (e.g., channel conditions, traffic at the base station, etc.) through downlink control information (DCI) transmitted to the UE. In some examples, a cyclic redundancy check (CRC) of the DCI may be scrambled with an identification that indicates whether AUL transmissions are activated or deactivated at the UE. In some cases, the UE and base station may exchange various other control information to provide relatively efficient autonomous uplink transmissions and use of the shared radio frequency spectrum band resources, as discussed herein. 
     Aspects of the disclosure are initially described in the context of a wireless communications system. Further examples are then provided of AUL configurations and timelines. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to autonomous uplink transmission techniques using shared radio frequency spectrum. 
       FIG.  1    illustrates an example of a wireless communications system  100  in accordance with various aspects of the present disclosure. The wireless communications system  100  includes base stations  105 , UEs  115 , and a core network  130 . In some examples, the wireless communications system  100  may be a LTE (or LTE-Advanced) network, or a New Radio (NR) network. In some cases, wireless communications system  100  may support enhanced broadband communications, ultra-reliable (i.e., mission critical) communications, low latency communications, and communications with low-cost and low-complexity devices. Wireless communications system  100  may be an example of a system that supports autonomous uplink transmissions by UEs  115 . 
     Base stations  105  may wirelessly communicate with UEs  115  via one or more base station antennas. Each base station  105  may provide communication coverage for a respective geographic coverage area  110 . Communication links  125  shown in wireless communications system  100  may include uplink (UL) transmissions from a UE  115  to a base station  105 , or downlink (DL) transmissions, from a base station  105  to a UE  115 . Control information and data may be multiplexed on an uplink channel or downlink according to various techniques. Control information and data may be multiplexed on a downlink channel, for example, using time division multiplexing (TDM) techniques, frequency division  multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. In some examples, the control information transmitted during a transmission time interval (TTI) of a downlink channel may be distributed between different control regions in a cascaded manner (e.g., between a common control region and one or more UE-specific control regions). 
     UEs  115  may be dispersed throughout the wireless communications system  100 , and each UE  115  may be stationary or mobile. A UE  115  may also be referred to as a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology. A UE  115  may also be a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless phone, a personal electronic device, a handheld device, a personal computer, a wireless local loop (WLL) station, an Internet of things (IoT) device, an Internet of Everything (IoE) device, a machine type communication (MTC) device, an appliance, an automobile, or the like. 
     In some cases, a UE  115  may also be able to communicate directly with other UEs (e.g., using a peer-to-peer (P2P) or device-to-device (D2D) protocol). One or more of a group of UEs  115  utilizing D2D communications may be within the coverage area  110  of a cell. Other UEs  115  in such a group may be outside the coverage area  110  of a cell, or otherwise unable to receive transmissions from a base station  105 . In some cases, groups of UEs  115  communicating via D2D communications may utilize a one-to-many (1:M) system in which each UE  115  transmits to every other UE  115  in the group. In some cases, a base station  105  facilitates the scheduling of resources for D2D communications. In other cases, D2D communications are carried out independent of a base station  105 . 
     Some UEs  115 , such as MTC or IoT devices, may be low cost or low complexity devices, and may provide for automated communication between machines, i.e., Machine-to-Machine (M2M) communication. M2M or MTC may refer to data communication technologies that allow devices to communicate with one another or a base station without human intervention. For example, M2M or MTC may refer to communications from devices that integrate sensors or meters to measure or capture information and relay that information to a central server or application program that can make use of the information or present the  information to humans interacting with the program or application. Some UEs  115  may be designed to collect information or enable automated behavior of machines. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business charging. 
     In some cases, an MTC device may operate using half-duplex (one-way) communications at a reduced peak rate. MTC devices may also be configured to enter a power saving “deep sleep” mode when not engaging in active communications. In some cases, MTC or IoT devices may be designed to support mission critical functions and wireless communications system may be configured to provide ultra-reliable communications for these functions. 
     Base stations  105  may communicate with the core network  130  and with one another. For example, base stations  105  may interface with the core network  130  through backhaul links  132  (e.g., S1, etc.). Base stations  105  may communicate with one another over backhaul links  134  (e.g., X2, etc.) either directly or indirectly (e.g., through core network  130 ). Base stations  105  may perform radio configuration and scheduling for communication with UEs  115 , or may operate under the control of a base station controller (not shown). In some examples, base stations  105  may be macro cells, small cells, hot spots, or the like. Base stations  105  may also be referred to as eNodeBs (eNBs)  105 . 
     Aspects of wireless communications system  100  may be configured as a MuLTEFire network, and an access point (AP) may be configured as a MuLTEFire eNB or base station  105 . Wireless communications system  100  may include aspects of an LTE/LTE-A network, a Wi-Fi network, a MuLTEFire network, a neutral host small cell network, or the like, operating with overlapping coverage areas. A MuLTEFire network may include APs and/or base stations  105  communicating with UEs  115  in unlicensed radio frequency spectrum band, e.g., without a licensed radio frequency anchor carrier. For example, the MuLTEFire network may operate without an anchor carrier in licensed radio frequency spectrum. 
     In some cases, UE  115  and base station  105  may operate in a shared radio frequency spectrum band, which may include licensed RF spectrum, unlicensed RF spectrum, or a combination of licensed and unlicensed RF spectrum. For example, wireless  communications system  100  may employ LTE License Assisted Access (LTE-LAA) or LTE Unlicensed (LTE U) radio access technology or NR technology in an unlicensed band such as the 5 GHz Industrial, Scientific, and Medical (ISM) band. In an unlicensed frequency portion of the shared radio frequency spectrum band, UEs  115  or base stations  105  may traditionally perform a medium-sensing procedure to contend for access to the frequency spectrum. For example, UE  115  or base station  105  may perform an LBT procedure such as a clear channel assessment (CCA) prior to communicating in order to determine whether the shared channel is available. In some cases, AUL transmissions may follow similar LBT rules as used for grant-based uplink transmissions, such as category  4  LBT rules. 
     A CCA may include an energy detection or energy sensing procedure to determine whether there are any other active transmissions. For example, each UE  115  may randomly choose a backoff counter (with may be a certain duration or a number of symbols) and listen to a channel including resources the UEs  115  are contending for until the counter decrements to zero. If the counter reaches zero for a certain UE  115  and no other transmissions are detected, the UE  115  may start transmitting. If the counter does not reach zero before another signal is detected, the UE  115  has lost contention for resource and refrains from transmitting. 
     In some examples, a UE  115  may infer that a change in a received signal strength indicator (RSSI) of a power meter indicates that a channel is occupied. Specifically, signal power that is concentrated in a certain bandwidth and exceeds a predetermined noise floor may indicate another wireless transmitter. A CCA also may include detection of specific sequences that indicate use of the channel. For example, another device may transmit a specific preamble prior to transmitting a data sequence. In some cases, an LBT procedure may include a wireless node adjusting its own backoff window based on the amount of energy detected on a channel and/or the acknowledge/negative-acknowledge (ACK/NACK) feedback for its own transmitted packets as a proxy for collisions. 
     Base stations  105  may wirelessly communicate with UEs  115  via one or more base station antennas. Each base station  105  may provide communication coverage for a respective geographic coverage area  110 . Communication links  125  shown in wireless communications system  100  may include uplink transmissions from a UE  115  to a base station  105 , or downlink transmissions, from a base station  105  to a UE  115 . UEs  115  may be dispersed throughout the wireless communications system  100 , and each UE  115  may be stationary or mobile. Although a base station  105  may generally refer to aspects of wireless  wide area networks (WWANs) and an AP may generally refer to aspects of WLANs, base station and AP may be used interchangeably. As discussed below, a base station  105  may identify conditions (e.g., number of hidden nodes) of a UE  115 , and the core network  130 , via base station  105 , may configure the UE  115  accordingly. 
     UEs  115  and base stations  105  may employ a hybrid automatic repeat request (HARQ) feedback mechanism, which may be a method of ensuring that data is received correctly over a communication link  125 . 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 may improve throughput at the media access control (MAC) layer in poor radio conditions (e.g., signal-to-noise conditions). In Incremental Redundancy HARQ, incorrectly received data may be stored in a buffer and combined with subsequent transmissions to improve the overall likelihood of successfully decoding the data. In some cases, redundancy bits (e.g., a redundancy version (RV) or a new data indicator (NDI)) are added to each message prior to transmission. This may be useful in poor conditions. In other cases, redundancy 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. The 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 . 
     In some examples, unscheduled PUSCH transmissions may use asynchronous HARQ processes, and certain retransmission options may be used. For example, a UE  115  may send a retransmission upon receipt of a NACK, where a base station  105  may win contention for the medium to send the NACK feedback. Additionally or alternatively, retransmission may be based on receipt of NACK or a timer when no ACK/NACK feedback is received. In some cases, the timer may increase the chance of a PUSCH being received. 
     Bidirectional communications may use frequency division duplexing (FDD) (e.g., using paired spectrum resources) or time division duplexing (TDD) operation (e.g., using unpaired spectrum resources). Frame structures for FDD (e.g., frame structure type 1) and TDD (e.g., frame structure type 2) may be defined. For TDD frame structures, each subframe may carry uplink or downlink traffic, and special subframes may be used to switch between downlink and uplink transmission. Allocation of uplink and downlink subframes within radio  frames may be symmetric or asymmetric and may be statically determined or may be reconfigured semi-statically. Special subframes may carry downlink or uplink traffic and may include a guard period (GP) between downlink and uplink traffic. Switching from uplink to downlink traffic may be achieved by setting a timing advance at the UE  115  without the use of special subframes or a guard period. Uplink-downlink configurations with switch-point periodicity equal to the frame period (e.g., 10 ms) or half of the frame period (e.g., 5 ms) may also be supported. 
     For example, TDD frames may include one or more special frames, and the period between special frames may determine the TDD DL-to-UL switch-point periodicity for the frame. Use of TDD offers flexible deployments without requiring paired UL-DL spectrum resources. In some TDD network deployments, interference may be caused between uplink and downlink communications (e.g., interference between uplink and downlink communication from different base stations, interference between uplink and downlink communications from base stations and UEs, etc.). For example, where different base stations  105  serve different UEs  115  within overlapping coverage areas according to different TDD UL-DL configurations, a UE  115  attempting to receive and decode a downlink transmission from a serving base station  105  may experience interference from uplink transmissions from other, proximately located UEs  115 . 
     In some cases, a UE  115  may be detectable by a central base station  105  (or AP), but not by other UEs  115  in the coverage area  110  of the central base station  105 . For example, one UE  115  may be at one end of the coverage area  110  of the central base station  105  while another UE  115  may be at the other end (e.g., a hidden node). Thus, both UEs  115  may communicate with the base station  105 , but may not receive the transmissions of the other. This may result in colliding transmissions for the two UEs  115  in a contention based environment (e.g., carrier sense multiple access with collision avoidance (CSMA/CA)) because the UEs  115  may not refrain from transmitting on top of each other. A UE  115  whose transmissions are not identifiable, but that is within the same coverage area  110  may be known as a hidden node. In some examples described herein, a UE  115  and base station  105  of interest may be referred to as a victim UE  115  or victim AP in the presence of a potentially interfering neighbor UE  115  or AP (e.g., a hidden node), which may be further referred to as an aggressor UE  115  or aggressor AP.  
     In some cases, intra-cell UE ambiguity and transmission collisions may result in decreased system performance (e.g. due to timing synchronization issues). Intra-cell UE ambiguity and/or transmission collisions may arise in scenarios where two or more UEs  115  are unable to detect each other (e.g. the hidden node issue described above). In some cases, a grant may be used by a base station  105  to allocate resources to UEs  115 . In AUL, the base station  105  may detect the presence of the PUSCH and identify a UE  115  through a DMRS or scheduling request (SR). After one AUL UE  115  successfully contends the medium, the base station  105  may detect its PUSCH. However, since other intra-cell UEs  115  may not detect the DMRS and SR from this UE  115 , another intra-cell UE (e.g., an aggressor) may also successfully contend the medium. As a result, the base station  105  may have a misaligned TDD configuration and frame start-timing, which may result in a collision between the transmissions from the two UEs  115 . In some cases, a base station may enable or disable AUL transmissions at a UE  115  to reduce the likelihood of interference between multiple AUL transmissions, as will be discussed in further detail below. 
     Time intervals may be expressed in multiples of a basic time unit (which may be a sampling period of T s =1/30,720,000 seconds). Time resources may be organized according to radio frames of length of 10 ms (T f =307200T s ), which may be identified by a system frame number (SFN) ranging from 0 to 1023. Each frame may include ten 1 ms subframes numbered from 0 to 9. A subframe may be further divided into two 0.5 ms slots, each of which contains 6 or 7 modulation symbol periods (depending on the length of the cyclic prefix prepended to each symbol). Excluding the cyclic prefix, each symbol may contain  2048  sample periods. However, in some cases as described below, symbols within wireless communications system  100  may also have different durations. In some cases the subframe may be the smallest scheduling unit, also known as a TTI. In other cases, a TTI may be shorter than a subframe or may be dynamically selected (e.g., in short TTI bursts or in selected component carriers using short TTIs). 
     Each frame may include ten 1 ms subframes numbered from 0 to 9; other frame structures may also be employed, as discussed below. A subframe may be further divided into two 0.5 ms slots, each of which contains 6 or 7 modulation symbol periods (depending on the length of the cyclic prefix prepended to each symbol). A resource element may consist of one symbol period and one subcarrier (a 15 KHz frequency range). A resource block may contain 12 consecutive subcarriers in the frequency domain and, for a normal cyclic prefix in each  orthogonal frequency division multiplexing (OFDM) symbol, 7 consecutive OFDM symbols in the time domain (1 slot), or 84 resource elements. 
     Excluding the cyclic prefix, each symbol may contain  2048  sample periods. In some cases the subframe may be the smallest scheduling unit, also known as a transmission time interval. In other cases, a TTI may be shorter than a subframe or may be dynamically selected (e.g., in short TTI bursts or in selected component carriers using short TTIs). A subframe may have different structures depending on the type and direction of information to be transmitted. A subframe type may be an uplink subframe, a downlink subframe, or a special (S) subframe. Special subframes may facilitate a switch from downlink to uplink transmission. Further the structure of a subframe may vary in terms of length. Other frame structures may also be employed in wireless communications system  100 . In some cases, wireless communications system  100  may be organized by transmission opportunities (TxOPs), which may be organized according to the frame structure described above and which a may be separated by periods of time during which the wireless medium may be unavailable for devices (e.g., UEs  115  or base stations  105 ) within wireless communications system  100 . 
     In some cases, wireless communications system  100  may utilize enhanced component carriers (eCCs). An eCC may be characterized by one or more features including: wider bandwidth, shorter symbol duration, shorter transmission time interval (TTIs), and modified control channel configuration. In some cases, an eCC may be associated with a carrier aggregation configuration or a dual connectivity configuration (e.g., when multiple serving cells have a suboptimal or non-ideal backhaul link). An eCC may also be configured for use in unlicensed spectrum or shared spectrum (where more than one operator is allowed to use the spectrum). An eCC characterized by wide bandwidth may include one or more segments that may be utilized by UEs  115  that are not capable of monitoring the whole bandwidth or prefer to use a limited bandwidth (e.g., to conserve power). 
     In some cases, an eCC may utilize a different symbol duration than other CCs, which may include use of a reduced symbol duration as compared with symbol durations of the other CCs. A shorter symbol duration may be associated with increased subcarrier spacing. A TTI in an eCC may consist of one or multiple symbols. In some cases, the TTI duration (that is, the number of symbols in a TTI) may be variable. A device, such as a UE  115  or base station  105 , utilizing eCCs may transmit wideband signals (e.g., 20, 40, 60, 80  MHz, etc.) at reduced symbol durations (e.g., 16.67 microseconds). A TTI in eCC may consist of one or multiple symbols. In some cases, the TTI duration (that is, the number of symbols in a TTI) may be variable. 
     As indicated above, one or more UEs  115  may operate in an autonomous (i.e., unscheduled) uplink mode. When operating in an AUL mode, UEs  115  may use an autonomous control channel (e.g., A-PUCCH) configuration. These A-PUCCH configurations may be configured according to UE  115  or system needs or constraints in various examples. 
     In some cases, wireless communications system  100  may support different uplink transmission configurations for different UEs  115  (e.g., mixed mode scheduling). That is, a first UE  115  may operate using AUL transmissions (which may be used in addition to scheduled uplink transmissions) and other UEs  115  may use scheduled uplink transmissions. Such mixed-mode scheduling may be associated with enhanced communications performance within the system, and a base station  105  may enable or disable AUL transmissions at different UEs  115  to provide such mixed-mode scheduling. As a result, configurations for UEs  115  that may operate using unscheduled and/or scheduled uplink transmissions may be determined by a serving base station  105 . 
     A UE  115  configured for AUL may, in some examples, perform channel contention and gain access to a shared radio frequency spectrum band, according to an AUL configuration that may be provided to the UE  115  by a base station  105 . In some cases, the UE  115  may modify an uplink waveform or provide an indication to the base station  105  of one or more channel resources that may be available for base station  150  transmissions, in order to more fully utilize shared radio frequency spectrum band resources within a MCOT. In some examples, a CRC of a DCI may be scrambled with an identification that indicates whether AUL transmissions are activated or deactivated at a particular UE  115 . In some cases, the UE  115  and base station  105  may exchange various other control information to provide relatively efficient autonomous uplink transmissions and use of the shared radio frequency spectrum band resources, as discussed herein. 
       FIG.  2    illustrates an example of a wireless communications system  200  that supports autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with various aspects of the present disclosure. Wireless communications system  200  may include a base station  105 - a  and UE  115 - a  that may be examples of the  corresponding devices described with reference to  FIG.  1   . For example, UE  115 - a  may be time-synchronized with base station  105 - a , and may be capable of unscheduled or AUL transmissions to base station  105 - a . In some examples, the base station  105 - a  may enable the UE  115 - a  for AUL transmissions through downlink transmissions  205  (e.g., RRC signaling) that includes AUL configuration information  210 . The UE  115 - a  may perform a contention procedure to gain channel access, and may transmit uplink transmissions  215  which may contain AUL transmissions  220 . 
     In wireless communications system  200 , as described in more detail below, the AUL transmissions  220  and associated control information may be transmitted between base station  105 - a  and UE  115 - a  in a manner that provides enhanced efficiency shared resources such as resources of a shared radio frequency spectrum band. For example, UE  115 - a  may have data that is to be transmitted using an AUL transmission  220 , and may determine that data to be transmitted in the AUL transmission spans less than a total duration of the transmission opportunity (TxOP) acquired by the UE  115 - a  as part of the channel contention process. In such cases, the UE  115 - a  may signal to the base station  105 - a  a number of subframes of the TxOP that are unused, and that may then be used by the base station  105 -a. In such a manner, both the UE  115 - a  and the base station  105 - a  may more efficiently use the shared resources and increase system throughput and efficiency. In some cases, the AUL transmission  220  may occupy the entire TxOP or nearly the entire TxOP, and the UE  115 - a  may modify a waveform of the AUL transmission in order to provide a gap during which the base station  105 - a  may perform an LBT procedure. 
     An example of such a gap is illustrated in  FIG.  3   , which illustrates an example of shared channel resources  300  that support autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with various aspects of the present disclosure. Shared channel resources  300  may be utilized by base stations  105  and UEs  115  as described with reference to  FIGS.  1  and  2   . 
     As indicated above, in some cases it may be desirable to provide a gap between an AUL transmission and a subsequent downlink transmission of a base station, during which the base station may perform a LBT procedure. Furthermore, in some cases, regulations associated with shared channel contention procedures may specify a maximum gap between transmissions between a UE and a base station. For example, ETSI regulations specify a maximum gap of 25 μs between base station and UE transmissions, and in some cases a base  station may transmit a cell-specific reference signal (CRS) in a first symbol of a downlink transmission that the UE may use to detect transmission from the base station. 
     With reference to the shared channel resources  300  of  FIG.  3   , the UE may perform a CCA  305  and gain access to the shared channel resources  300 , and may transmit AUL transmission  310 . Synchronized timing in the system may provide that a downlink transmission starts in a first downlink subframe  320  that is subsequent to a last uplink subframe  325 . As indicated above, the UE may leave a gap  315  between the last uplink subframe  325  and the first downlink subframe  320  during which the base station may perform channel contention. Further, a maximum time period (e.g., X μs) may be specified in certain cases. Additionally, the UE may apply a timing advance (TA) when transmitting uplink transmissions, so as to provide uplink transmissions that arrive at the base station and provide system synchronization. The TA may be used to compensate for propagation delay of the AUL transmission  310  between the UE and the base station, and may be determined by the UE according to established techniques for determining TA. 
     In such examples, a UE may modify the uplink transmission waveform, or provide signaling to a base station, that provides the gap  315  and also complies with any specified maximum time gap. In some examples, the UE may generate an uplink waveform that spans the entire duration of the AUL transmission  310 , and then puncture the last (X-TA) μs of the AUL transmission  310  in the last symbol of the last downlink subframe  325 . In other examples, the UE may generate an uplink waveform that spans a time that is one symbol less than the entire duration of the AUL transmission  310 , and may cyclically extend sample of the last symbol of the waveform (X-TA) μs before the boundary of the first downlink subframe  320 . In some examples, if the TA is more than X μs, then the base station may performs the channel contention procedure and transmit a reservation signal for TA μs until the boundary of the first downlink subframe  320 . In some cases, autonomous uplink control information (A-UCI) may be transmitted in the AUL transmission  310 , and in such cases, if A-UCI is transmitted in the last uplink subframe  325 , then the physical channel carrying A-UCI (A-PUCCH for example) is not defined for the last symbol of the last uplink subframe, and may thus be reliably transmitted without being punctured. The base station may then perform a X μs CCA to start the downlink transmission at the first downlink subframe  320 . 
       FIG.  4    illustrates an example of a process flow  400  that supports autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with  various aspects of the present disclosure. Process flow  400  may include a UE  115 - b  and base station  105 - b , which may be respective examples of a UE  115  and a base station  105  as described herein with reference to  FIGS.  1 - 2   . Process flow  400  may be an example of the use of different autonomous uplink transmission techniques, where UE  115 - b  may transmit one or more channel access parameters that may be used by base station  105 - a  to opportunistically transmit one or more downlink transmissions within a UE-acquired MCOT. 
     The base station  105 - b  may determine an AUL configuration for the UE  115 - b , and may transmit the AUL configuration  405  in a downlink transmission to the UE  115 - b . In some cases, the AUL configuration  405  may be transmitted using RRC signaling. 
     At block  410 , the UE  115 - b  may identify the AUL configuration and, based on the AUL configuration, may identify that data is to be transmitted to the base station  105 - b  using one or more AUL transmissions. In some cases, the AUL configuration may include a time period during which the UE  115 - b  may transmit AUL transmissions, and provide various parameters (e.g., MCS, uplink power control parameters, etc.). In some cases, the AUL configuration may include information on a type of channel contention procedure that may be performed by the UE  115 - b , such as a Cat-4 or a Cat-2 LBT, for example. 
     At block  415 , the UE  115 - b  may perform an LBT procedure in accordance with the AUL configuration. In some cases, the UE  115 - b  may perform a CCA in order to confirm that a channel of a shared radio frequency spectrum band is unoccupied by another transmitter, in a manner similarly as discussed above. In some cases, the LBT procedure may be successful and the UE  115 - b  may gain channel access and may identify a MCOT associated with the AUL transmissions. In some cases, the AUL configuration may provide that the UE  115 - b  acquires the channel of the shared radio frequency spectrum band according to a MCOT acquired by the base station  105 -b. In other cases, the AUL configuration may provide that the UE  115 - b  may acquire its own MCOT as part of the LBT procedure  415 . In cases where the UE  115 - b  may perform a Cat-4 LBT and acquire its own MCOT, the timing for starting the LBT may be up to UE  115 - b  implementation, and the MCOT may be determined by the UE  115 - b . In some cases, the UE  115 - b  may decide the LBT priority class, and where MCOT is acquired by the UE  115 - b  a portion of the MCOT may be shared with the base station  105 - b.    
     At block  420 , the UE  115 - b  may determine an uplink transmission duration and a TA for the AUL transmission. The uplink transmission duration may be determined, for  example, based on an amount of data to be transmitted in the AUL transmission, a time period available for the AUL transmission, a MCS for AUL transmissions, or any combination thereof. In some cases, the TA may be identified based on a propagation delay for a signal transmitted between the UE  115 - b  and the base station  105 - b , according to established TA determination techniques. 
     At block  425 , the UE  115 - b  may determine channel access parameters associated with the AUL transmission, and may transmit AUL transmission  430 , including the access parameters, to the base station  105 - b . As indicated above, in some cases that UE  115 - b  may acquire the MCOT, and may share the MCOT with the base station  105 - b . In such cases, the channel access parameters may include an indication that the base station  105 - b  may share the MCOT. In some cases, LBT priority class as part of the channel access parameters, and the base station  105 - b  may use portions of the MCOT that are unused by the UE  115 - b . In some cases, the base station may not be able to autonomously estimate the exact duration of AUL transmission  430 , such as due to burst interference at reception for example, and thus signaling LBT priority class as part of the channel access parameters may not allow the base station  105 - b  to reliably estimate available resources that may be used for downlink transmissions. Thus, in some examples, the channel access parameters may include a number of subframes that can be used by the base station  105 - b  within the UE  115 - b  acquired TxOP. 
     In some cases, the channel access parameters may be signaled to the base station  105 - b  in uplink control information (A-UCI) provided in the AUL transmission  430 . In some cases, the channel access parameters may include an indication associated with the gap between uplink transmissions and a subframe boundary of a subsequent downlink transmission, which may allow the base station  105 - b  to, for example, initiate a LBT procedure during the gap. In some examples, the base station  105 - b  may transmit downlink transmissions within the UE-acquired TxOP, but may not share the UE-acquired TxOP with other UEs in the system. 
     At block  435 , the base station  105 - b  may identify subframes available for a subsequent downlink transmission. Such a determination may be made according to the channel access parameters provided by the UE  115 - b , for example, as discussed above. The base station  105 - b  may then transmit one or more downlink transmissions  440  to the UE  115 - b.     
     In some examples, the UE  115 - b  may have more data to be transmitted in AUL transmissions than may fit in the resources acquired by the UE  115 - b . In some examples, if the UE  115 - b  has more data to transmit, the AUL configuration may provide that UE  115 - b  may continue AUL transmissions in certain cases. In some cases, the AUL configuration may provide for UE  115 - b  scheduling in Mode 1 that provides scheduling within a base station  105 - b  acquired MCOT, or in Mode 2 that provides for UE-acquired MCOT with Cat-4 LBT (which may be converted to Mode 1 if the base station  105 - b  obtains channel access at least a subframe or two before the UE  115 - b  can transmit). If the UE  115 - b  continues beyond it scheduled subframes in Mode 1, then it may interfere with transmissions from other UEs unless explicitly signaled otherwise. Thus, in some examples, the UE  115 - b  may be allowed to continue AUL transmissions in Mode 2 when the UE performs Cat 4 LBT. The first subframe of the subsequent AUL transmission in such cases may include A-PUCCH signaling that may indicate that the UE  115 - b  is continuing AUL transmissions. In some cases, the AUL transmissions  430  may be MIMO transmissions, and the AUL configuration may provide for Rank 2 uplink MIMO AUL transmissions. 
       FIG.  5    illustrates an example of another process flow  500  that supports autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with various aspects of the present disclosure. Process flow  500  may include a UE  115 - c  and base station  105 - c , which may be respective examples of a UE  115  and a base station  105  as described herein with reference to  FIGS.  1 - 2   . Process flow  500  may be an example of the use of different autonomous uplink transmission techniques, where UE  115 - c  may be configured to enable/disable AUL transmissions based on DCI. 
     The base station  105 - c  may determine an AUL configuration for the UE  115 - c , and may transmit the AUL configuration  505  in a downlink transmission to the UE  115 - c . In some cases, the AUL configuration  505  may be transmitted using RRC signaling. 
     At block  510 , the base station  105 - c  may determine to enable the UE  115 - b  to for AUL transmissions. Such a determination may be made, for example, on an amount of information present at the UE  115 - c  for transmission (e.g., as reported in a buffer status report (BSR)), one or more other UEs that may be configured for AUL transmissions, channel conditions, network traffic conditions, one or more other parameters, or any combination thereof.  
     At block  515 , the base station  105 - c  may scramble a DCI CRC with a UE identifier that enables AUL transmissions. In some examples, the UE identifier may be a AUL radio network temporary identifier (AUL-RNTI) that enables AUL transmissions from the UE  115 - c . In some examples, a CRC for the DCI may be generated, and then scrambled with the AUL-RNTI. The base station  105 - c  may then transmit the DCI  520  with scrambled CRC. 
     At block  525 , the UE  115 - c  may receive the DCI and perform an autonomous uplink LBT procedure. In some cases, the UE  115 - c  may perform a blind decode of the scrambled DCI according, and determine that AUL transmissions have been activated when the blind decode according to the AUL-RNTI scrambled CRC is successful in decoding the CRC of the DCI. In some cases, the DCI may provide semi-persistent scheduling (SPS) for the UE  115 - c , which may be used for AUL transmissions. Based on a successful channel contention procedure, the UE  115 - c  may then transmit AUL transmission  530 . The UE  115 - c  may continue channel contention procedures and AUL transmissions according to the SPS, in some examples. 
     At block  535 , the base station  105 - c  may determine to disable AUL transmissions at the UE  115 - c . Such a determination may be made in a similar manner as discussed above for determining to enable AUL transmissions, and be based on one or more of the same parameters. 
     At block  540 , the base station  105 - c  may scramble a DCI CRC with a UE identifier that disables AUL transmissions. In some cases, the DCI CRC may simply be transmitted without scrambling, which may indicate to the UE  115 - c  that AUL transmission are disabled. In some cases, a different RNTI may optionally be used to scramble the CRC, which may indicate to the UE  115 - c  that AUL transmissions are disabled. The base station  105 - c  may transmit DCI  545  to the UE  115 - c.    
     At block  550 , the UE  115 - c  may receive the DCI  545 , and discontinue unscheduled AUL transmissions. In some examples, the UE  115 - c  may make a determination to discontinue AUL transmissions based on whether the CRC of the DCI is scrambled or not, or based on an identifier used to scramble the CRC. 
       FIG.  6    illustrates an example of another process flow  600  that supports autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with various aspects of the present disclosure. Process flow  600  may include a  UE  115 - d  and base station  105 - d , which may be respective examples of a UE  115  and a base station  105  as described herein with reference to  FIGS.  1 - 2   . 
     The base station  105 - d  may determine an AUL configuration for the UE  115 -d, and may transmit the AUL configuration  605  in a downlink transmission to the UE  115 - d . In some cases, the AUL configuration  605  may be transmitted using RRC signaling. 
     At block  610 , the UE  115 - d  may identify the AUL configuration and, based on the AUL configuration, may identify that data is to be transmitted to the base station  105 - d  using one or more AUL transmissions. In some cases, the AUL configuration may include a time period during which the UE  115 - d  may transmit AUL transmissions, and provide various parameters (e.g., MCS, uplink power control parameters, etc.). 
     At block  615 , the UE  115 - d  may perform an LBT procedure in accordance with the AUL configuration. In some cases, the UE  115 - d  may perform a CCA in order to confirm that a channel of a shared radio frequency spectrum band is unoccupied by another transmitter, in a manner similarly as discussed above. In some cases, the LBT procedure may be successful and the UE  115 - d  may gain channel access. 
     At block  620 , the UE  115 - d  may determine UCI for transmission with one or more AUL transmissions. The UCI may include, for example, one or more channel access parameters as discussed above, a HARQ ID, a burst length, a MCOT, a RV, a NDI, a AUL-RNTI, or any combination thereof 
     At block  625 , the UE  115 - d  may rate match the UCI and PUSCH information within uplink resources. In some cases, the UE  115 - d  may embed the A-UCI information by PUSCH rate matching in a similar manner as periodic CSI and ACK/NACK is carried on PUSCH in legacy LTE systems. In some cases, the base station  105 - d  may signal a number of resources used for rate matching. In some cases, the UCI payload may be a fixed size, and additionally or alternatively may be independent of the actual number of subframes that can be addressed by A-UCI (e.g. payload is budgeted for 4 subframe transmission). After rate-matching, the UE  115 - d  may transmit AUL transmission  630  to the base station  105 - d.    
       FIG.  7    illustrates an example of another process flow  700  that supports autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with various aspects of the present disclosure. Process flow  700  may include a  UE  115 - e  and base station  105 - e , which may be respective examples of a UE  115  and a base station  105  as described herein with reference to  FIGS.  1 - 2   . 
     The base station  105 - e  may determine an AUL configuration for the UE  115 - e , and may transmit the AUL configuration  705  in a downlink transmission to the UE  115 - e . In some cases, the AUL configuration  705  may be transmitted using RRC signaling. 
     At block  710 , the UE  115 - e  may identify the AUL configuration and, based on the AUL configuration, may identify that data is to be transmitted to the base station  105 - e  using one or more AUL transmissions. In some cases, the AUL configuration may include a time period during which the UE  115 - e  may transmit AUL transmissions, and provide various parameters (e.g., MCS, uplink power control parameters, etc.). 
     At block  715 , the UE  115 - e  may perform an LBT procedure in accordance with the AUL configuration. In some cases, the UE  115 - e  may perform a CCA in order to confirm that a channel of a shared radio frequency spectrum band is unoccupied by another transmitter, in a manner similarly as discussed above. In some cases, the LBT procedure may be successful and the UE  115 - e  may gain channel access and transmit AUL transmission  720 . 
     At block  725 , the base station  105 - e  may perform HARQ processing and determine one or more uplink transmission parameters. In some cases, base station  105 - e  may perform HARQ processing and generate a bitmap of ACK/NACK indicators for all the HARQ-processes, and in some cases ACK/NACK indicators may be bundled to save bits. In some cases, the one or more uplink transmission parameters may include uplink power control information. In some cases, a CQI and MCS update may be included in the uplink transmission parameters, and may be transmitted in a medium access control (MAC) control element (CE) in order to have the base station  105 - e  receive an acknowledgement from the UE  115 - e  to acknowledge reception. In some cases, the MAC-CE may be scrambled with the AUL-RNTI for the UE  115 - e , and the UE  115 - e  may monitors for this grant for X ms after it has completed AUL transmission  720 . Beyond Xms the UE  115 - e  may consider the AUL transmission  720  is lost and may initiate retransmission procedures. 
     At block  730 , the base station  105 - e  may format the HARQ processing and UL transmission parameters into an A-DCI. The A-DCI  735  may be transmitted to the UE  115 - e  in a subsequent downlink transmission to the UE  115 - e . In some examples, CQI or a MCS indicator may be provided in a MAC control element (CE) transmitted over a shared channel transmission. In some examples, the one or more uplink transmission parameters (e.g., the  uplink power control information) may be formatted into an A-DCI. For example, the CQI or the MCS indicator may be included in the one or more uplink transmission parameters, and may be transmitted in the A-DCI  735 . In some examples, the CQI indicator may also include a precoding matrix indicator. 
     At block  740 , the UE  115 - e  may perform A-DCI and HARQ processing. Based on the processing, the UE  115 - e  may determine whether one or more AUL transmissions are to be retransmitted, and may determine one or more parameters for subsequent uplink transmissions, such as power control parameters, MCS, etc. In some cases, the UE  115 - e  may receive the MAC-CE with the CQI and MCS, and may generate an ACK/NACK for the MAC-CE as part of HARQ processing, thus allowing the base station  105 - e  to confirm that the CQI and MCS were successfully received. 
     At block  745 , the UE  115 - e  may perform another LBT procedure in accordance with the AUL configuration. Upon successful LBT and gaining channel access, the UE  115 - e  may transmit a subsequent AUL transmission  750 . The AUL transmission  750  may be transmitted according to one or more transmission parameters included in A-DCI  735 , and may include an ACK/NACK indication of whether the MAC-CE was successfully received. 
       FIG.  8    shows a block diagram  800  of a wireless device  805  that supports autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with various aspects of the present disclosure. Wireless device  805  may be an example of aspects of a user equipment (UE)  115  as described with reference to  FIG.  1   . Wireless device  805  may include receiver  810 , UE autonomous uplink manager  815 , and transmitter  820 . Wireless device  805  may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses). 
     Receiver  810  may 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 autonomous uplink transmission techniques using shared radio frequency spectrum, etc.). Information may be passed on to other components of the device. The receiver  810  may be an example of aspects of the transceiver  1135  described with reference to  FIG.  11   . 
     UE autonomous uplink manager  815  may be an example of aspects of the UE autonomous uplink manager  1115  described with reference to  FIG.  11   .  UE autonomous uplink manager  815  and/or at least some of its various sub-components may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions of the UE autonomous uplink manager  815  and/or at least some of its various sub-components may be executed by a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), an field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure. The UE autonomous uplink manager  815  and/or at least some of its various sub-components may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical devices. In some examples, UE autonomous uplink manager  815  and/or at least some of its various sub-components may be a separate and distinct component in accordance with various aspects of the present disclosure. In other examples, UE autonomous uplink manager  815  and/or at least some of its various sub-components may be combined with one or more other hardware components, including but not limited to an I/O component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure. 
     In some examples, UE autonomous uplink manager  815  may contend for access to a channel of a shared radio frequency spectrum band in accordance with an autonomous uplink configuration which indicates a transmission window available for autonomous uplink transmissions, determine one or more channel access parameters based on one or more of a duration of an uplink transmission to be transmitted over the channel of the shared radio frequency spectrum band or a TA for the uplink transmission, and transmit the uplink transmission over the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration, where the uplink transmission indicates one or more of the channel access parameters. 
     In some cases, UE autonomous uplink manager  815  may receive RRC signaling including an autonomous uplink configuration for unscheduled autonomous uplink transmissions in a shared radio frequency spectrum band, receive DCI that activates autonomous uplink transmissions, contend for access to a channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration, and  transmit one or more autonomous uplink transmissions over the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration. 
     In some cases, UE autonomous uplink manager  815  may identify an autonomous uplink configuration for unscheduled uplink transmissions in a shared radio frequency spectrum band, contend for access to a channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration, determine uplink control information and uplink shared channel information for an uplink transmission to be transmitted over the channel of the shared radio frequency spectrum band, rate matching the uplink shared channel information around the uplink control information in the uplink transmission, and transmit the uplink transmission over the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration. 
     In some cases, UE autonomous uplink manager  815  may identify an autonomous uplink configuration for unscheduled uplink transmissions in a shared radio frequency spectrum band, receive A-DCI associated with one or more autonomous uplink transmissions, and transmit an autonomous uplink transmission over the shared radio frequency spectrum band in accordance with the autonomous uplink configuration and the A-DCI. 
     Transmitter  820  may transmit signals generated by other components of the device. In some examples, the transmitter  820  may be collocated with a receiver  810  in a transceiver module. For example, the transmitter  820  may be an example of aspects of the transceiver  1135  described with reference to  FIG.  11   . The transmitter  820  may include a single antenna, or it may include a set of antennas. 
       FIG.  9    shows a block diagram  900  of a wireless device  905  that supports autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with various aspects of the present disclosure. Wireless device  905  may be an example of aspects of a wireless device  805  or a UE  115  as described with reference to  FIGS.  1  and  8   . Wireless device  905  may include receiver  910 , UE autonomous uplink manager  915 , and transmitter  920 . Wireless device  905  may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses). 
     Receiver  910  may 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 autonomous uplink transmission techniques using shared  radio frequency spectrum, etc.). Information may be passed on to other components of the device. The receiver  910  may be an example of aspects of the transceiver  1135  described with reference to  FIG.  11   . 
     UE autonomous uplink manager  915  may be an example of aspects of the UE autonomous uplink manager  1115  described with reference to  FIG.  11   . UE autonomous uplink manager  915  may also include listen-before-talk (LBT) manager  925 , control information component  930 , data manager  935 , and autonomous uplink configuration manager  940 . 
     LBT manager  925  may contend for access to a channel of a shared radio frequency spectrum band in accordance with an autonomous uplink configuration. In some cases, the UAL configuration may indicate a transmission window available for autonomous uplink transmissions and LBT manager  925  may contend for access to a channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration. 
     Control information component  930  may determine one or more channel access parameters. In some cases, the channel access parameters may be based on one or more of a duration of an uplink transmission to be transmitted over the channel of the shared radio frequency spectrum band or a TA for the uplink transmission. In some cases, the control information component  930  may receive DCI that activates autonomous uplink transmissions, and receive subsequent DCI that deactivates autonomous uplink transmissions. In some cases, the control information component  930  may determine uplink control information and uplink shared channel information for an uplink transmission to be transmitted over the channel of the shared radio frequency spectrum band. 
     In some cases, the control information component  930  may receive A-DCI associated with one or more autonomous uplink transmissions. In some cases, the control information may include a CQI or a MCS indicator that is transmitted in a MAC-CE over a shared channel transmission, and an acknowledgment that the CQI or MCS are received may be provided. In some cases, the A-DCI includes a bitmap of feedback information associated with one or more feedback processes associated with one or more autonomous uplink transmission. In some cases, the A-DCI and/or MAC-CE includes uplink power control information for one or more autonomous uplink transmission.  
     In some cases, the difference between a MCOT and the duration of the uplink transmission is indicated in the channel access parameters as a number of subframes available for use by one or more other transmitters. In some cases, the DCI includes a CRC field scrambled with an identifier, and a value of the identifier indicates that the DCI is associated with autonomous uplink transmissions. In some cases, the one or more channel access parameters may include a MCOT for the uplink transmission, and a time difference between the MCOT and the duration of the uplink transmission. In some cases, a payload size of uplink control information may be a fixed size configured in the autonomous uplink configuration. In some cases, the payload size is independent of a number of subframes of the uplink transmission. In some cases, the resources used for the uplink control information and rate matching of the shared channel information is configured in the autonomous uplink configuration. 
     Data manager  935  may manage uplink transmissions. In some cases, data manager  935  may modify a waveform of the uplink transmission based on the TA, and transmit the uplink transmission over a channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration, where the uplink transmission indicates one or more of the channel access parameters. In some cases, data manager  935  may determine that additional data is to be transmitted following a transmission window for AUL transmissions, and transmit one or more subsequent uplink transmissions after the uplink transmission outside of the transmission window when a MCOT is determined as part of the contending for access to the channel of the shared radio frequency spectrum band. 
     In some cases, data manager  935  may determine that AUL transmissions are activated, transmit one or more autonomous uplink transmissions over the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration, and discontinue contending for access to the channel of the shared radio frequency spectrum band responsive to the receiving a DCI that deactivates autonomous uplink transmissions. In some cases, data manager  935  may rate match uplink shared channel information around the uplink control information in the uplink transmission. 
     Autonomous uplink configuration manager  940  may receive RRC signaling including an autonomous uplink configuration for unscheduled autonomous uplink transmissions in a shared radio frequency spectrum band and identify an autonomous uplink  configuration for unscheduled uplink transmissions in a shared radio frequency spectrum band. 
     Transmitter  920  may transmit signals generated by other components of the device. In some examples, the transmitter  920  may be collocated with a receiver  910  in a transceiver module. For example, the transmitter  920  may be an example of aspects of the transceiver  1135  described with reference to  FIG.  11   . The transmitter  920  may include a single antenna, or it may include a set of antennas. 
       FIG.  10    shows a block diagram  1000  of a UE autonomous uplink manager  1015  that supports autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with various aspects of the present disclosure. The UE autonomous uplink manager  1015  may be an example of aspects of a UE autonomous uplink manager  815 , a UE autonomous uplink manager  915 , or a UE autonomous uplink manager  1115  described with reference to  FIGS.  8 ,  9 , and  11   . The UE autonomous uplink manager  1015  may include LBT manager  1020 , control information component  1025 , data manager  1030 , autonomous uplink configuration manager  1035 , timing gap component  1040 , UCI manager  1045 , MIMO manager  1050 , and hybrid automatic repeat request (HARD) manager  1055 . Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses). 
     LBT manager  1020  may contend for access to a channel of a shared radio frequency spectrum band in accordance with an autonomous uplink configuration which indicates a transmission window available for autonomous uplink. 
     Control information component  1025  may determine one or more channel access parameters. In some cases, the one or more channel access parameters may be based on one or more of a duration of an uplink transmission to be transmitted over the channel of the shared radio frequency spectrum band or a TA for the uplink transmission. In some cases, the control information component  1025  may receive DCI that activates autonomous uplink transmissions, and receive subsequent DCI that deactivates autonomous uplink transmissions. In some cases, the control information component  1025  may determine uplink control information and uplink shared channel information for an uplink transmission to be transmitted over the channel of the shared radio frequency spectrum band. 
     In some cases, the control information component  1025  may receive A-DCI associated with one or more autonomous uplink transmissions. In some cases, a CQI or a  MCS indicator may be provided in a MAC-CE transmitted over a shared channel, and an acknowledgment that the CQI or MCS are received may be provided. In some cases, the A-DCI includes a bitmap of feedback information associated with one or more feedback processes associated with one or more autonomous uplink transmission. In some cases, the A-DCI and/or MAC-CE includes uplink power control information for one or more autonomous uplink transmission. 
     In some cases, the difference between a MCOT and the duration of the uplink transmission is indicated in the channel access parameters as a number of subframes available for use by one or more other transmitters. In some cases, the DCI includes a CRC field scrambled with an identifier, and a value of the identifier indicates that the DCI is associated with autonomous uplink transmissions. In some cases, the one or more channel access parameters may include a MCOT for the uplink transmission, and a time difference between the MCOT and the duration of the uplink transmission. In some cases, a payload size of uplink control information may be a fixed size configured in the autonomous uplink configuration. In some cases, the payload size is independent of a number of subframes of the uplink transmission. In some cases, the resources used for the uplink control information and rate matching of the shared channel information is configured in the autonomous uplink configuration. 
     Data manager  1030  may manage uplink transmissions. In some cases, data manager  1030  may modify a waveform of the uplink transmission based on the TA, and transmit the uplink transmission over a channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration, where the uplink transmission indicates one or more of the channel access parameters. In some cases, data manager  1030  may determine that additional data is to be transmitted following a transmission window for AUL transmissions, and transmit one or more subsequent uplink transmissions after the uplink transmission outside of the transmission window when a MCOT is determined as part of the contending for access to the channel of the shared radio frequency spectrum band. 
     In some cases, data manager  1030  may determine that AUL transmissions are activated, transmit one or more autonomous uplink transmissions over the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration, and discontinue contending for access to the channel of the shared radio frequency spectrum band responsive to the receiving a DCI that deactivates autonomous  uplink transmissions. In some cases, data manager  1030  may rate match uplink shared channel information around the uplink control information in the uplink transmission. 
     Autonomous uplink configuration manager  1035  may receive RRC signaling including an autonomous uplink configuration for unscheduled autonomous uplink transmissions in a shared radio frequency spectrum band and identify an autonomous uplink configuration for unscheduled uplink transmissions in a shared radio frequency spectrum band. 
     Timing gap component  1040  may identify a time for starting a subsequent downlink transmission following the uplink transmission, format the uplink transmission to occupy the channel of the shared radio frequency spectrum band until the time for starting the subsequent downlink transmission. In some cases, a transmitter of the subsequent downlink transmission performs a CCA to occupy a maximum time gap between the uplink transmission and the subsequent downlink transmission. In some cases, timing gap component  1040  may transmit a time difference between a MCOT and a duration of the uplink transmission to a base station, where the base station may transmit one or more transmissions during the time difference. In some cases, one or more other UEs may be precluded from transmitting during the time difference. 
     In some cases, a AUL waveform may be modified by formatting data to be transmitted into the uplink transmission, identifying a timing for starting a subsequent downlink transmission following the uplink transmission and a maximum time gap between the uplink transmission and the subsequent downlink transmission, determining a difference between the maximum time gap and the TA, and puncturing a last symbol of the uplink transmission for a duration of the difference between the maximum time gap and the TA. In some cases, the waveform may be modified by formatting data to be transmitted into the uplink transmission, identifying a timing for starting a subsequent downlink transmission following the uplink transmission and a maximum time gap between the uplink transmission and the subsequent downlink transmission, determining a time difference between an end of a last symbol of the uplink transmission and the maximum time gap, and cyclically extending samples of the last symbol of the uplink transmission to extend for a duration of the difference between the maximum time gap and the TA. In some cases, the determining one or more channel access parameters further includes determining that the TA exceeds a maximum time gap between the uplink transmission and a subsequent downlink transmission,  and where the TA is indicated in the uplink transmission to allow another transmitter to transmit a reservation signal for at least a portion of the TA. 
     UCI manager  1045  may identify UCI associated with the uplink transmission and transmit the UCI in a symbol of the uplink transmission before a last symbol of the uplink transmission. In some cases, a first subframe of a first subsequent uplink transmission of the one or more subsequent uplink transmissions includes control channel information that provides information on the one or more subsequent uplink transmissions. In some cases, UCI may include a burst length of the uplink transmission, a MCOT, a RV indication, a NDI, or an AUL-RNTI. 
     MIMO manager  1050  may enable autonomous uplink transmissions on one or more transmit antennas according to a MIMO configuration. HARQ manager  1055  may provide one or more of a HARQ identification and provide HARQ processing. In some cases, the HARQ feedback information includes one or more ACK/NACK indications for one or more HARQ processes. In some cases, the bits from two or more feedback processes are bundled. 
       FIG.  11    shows a diagram of a system  1100  including a device  1105  that supports autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with various aspects of the present disclosure. Device  1105  may be an example of or include the components of wireless device  805 , wireless device  905 , or a UE  115  as described above, e.g., with reference to  FIGS.  1 ,  8  and  9   . Device  1105  may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including UE autonomous uplink manager  1115 , processor  1120 , memory  1125 , software  1130 , transceiver  1135 , antenna  1140 , and I/O controller  1145 . These components may be in electronic communication via one or more busses (e.g., bus  1110 ). Device  1105  may communicate wirelessly with one or more base stations  105 . 
     Processor  1120  may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a central processing unit (CPU), a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, processor  1120  may be configured to operate a memory array using a memory controller. In other cases, a memory controller may be integrated into processor  1120 . Processor  1120  may be configured to  execute computer-readable instructions stored in a memory to perform various functions (e.g., functions or tasks supporting autonomous uplink transmission techniques using shared radio frequency spectrum). 
     Memory  1125  may include random access memory (RAM) and read only memory (ROM). The memory  1125  may store computer-readable, computer-executable software  1130  including instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory  1125  may contain, among other things, a basic input/output system (BIOS) which may control basic hardware and/or software operation such as the interaction with peripheral components or devices. 
     Software  1130  may include code to implement aspects of the present disclosure, including code to support autonomous uplink transmission techniques using shared radio frequency spectrum. Software  1130  may be stored in a non-transitory computer-readable medium such as system memory or other memory. In some cases, the software  1130  may not be directly executable by the processor but may cause a computer (e.g., when compiled and executed) to perform functions described herein. 
     Transceiver  1135  may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver  1135  may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver  1135  may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas. 
     In some cases, the wireless device may include a single antenna  1140 . However, in some cases the device may have more than one antenna  1140 , which may be capable of concurrently transmitting or receiving multiple wireless transmissions. 
     I/O controller  1145  may manage input and output signals for device  1105 . I/O controller  1145  may also manage peripherals not integrated into device  1105 . In some cases, I/O controller  1145  may represent a physical connection or port to an external peripheral. In some cases, I/O controller  1145  may utilize an operating system such as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, or another known operating system. In other cases, I/O controller  1145  may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, I/O controller  1145   may be implemented as part of a processor. In some cases, a user may interact with device  1105  via I/O controller  1145  or via hardware components controlled by I/O controller  1145 . 
       FIG.  12    shows a block diagram  1200  of a wireless device  1205  that supports autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with various aspects of the present disclosure. Wireless device  1205  may be an example of aspects of a base station  105  as described with reference to  FIG.  1   . Wireless device  1205  may include receiver  1210 , base station autonomous uplink manager  1215 , and transmitter  1220 . Wireless device  1205  may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses). 
     Receiver  1210  may 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 autonomous uplink transmission techniques using shared radio frequency spectrum, etc.). Information may be passed on to other components of the device. The receiver  1210  may be an example of aspects of the transceiver  1535  described with reference to  FIG.  15   . 
     Receiver  1210  may receive one or more autonomous uplink transmissions over the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration. 
     Base station autonomous uplink manager  1215  may be an example of aspects of the base station autonomous uplink manager  1515  described with reference to  FIG.  15   . 
     Base station autonomous uplink manager  1215  and/or at least some of its various sub-components may be implemented in hardware, software executed by a processor, firmware, or any combination thereof If implemented in software executed by a processor, the functions of the base station autonomous uplink manager  1215  and/or at least some of its various sub-components may be executed by 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 in the present disclosure. The base station autonomous uplink manager  1215  and/or at least some of its various sub-components may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical devices. In some examples, base station autonomous uplink manager  1215  and/or at least some of its various sub-components may be  a separate and distinct component in accordance with various aspects of the present disclosure. In other examples, base station autonomous uplink manager  1215  and/or at least some of its various sub-components may be combined with one or more other hardware components, including but not limited to an I/O component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure. 
     Base station autonomous uplink manager  1215  may configure a UE for autonomous uplink transmissions in a shared radio frequency spectrum band, receive an autonomous uplink transmission from the UE over the shared radio frequency spectrum band, the autonomous uplink transmission including one or more channel access parameters, and transmit a downlink transmission over the shared radio frequency spectrum band in accordance with one or more of the channel access parameters. The base station autonomous uplink manager  1215  may also transmit RRC signaling to a UE that includes an autonomous uplink configuration for unscheduled autonomous uplink transmissions in a shared radio frequency spectrum band, determine that the autonomous uplink transmissions should be activated for the UE, transmit DCI that activates autonomous uplink transmissions responsive to determining that the autonomous uplink transmissions should be activated for the UE, determine that that the autonomous uplink transmissions should be deactivated for the UE, and transmit DCI that deactivates the autonomous uplink transmissions responsive to determining that the autonomous uplink transmissions should be deactivated for the UE. 
     Transmitter  1220  may transmit signals generated by other components of the device. In some examples, the transmitter  1220  may be collocated with a receiver  1210  in a transceiver module. For example, the transmitter  1220  may be an example of aspects of the transceiver  1535  described with reference to  FIG.  15   . The transmitter  1220  may include a single antenna, or it may include a set of antennas. 
       FIG.  13    shows a block diagram  1300  of a wireless device  1305  that supports autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with various aspects of the present disclosure. Wireless device  1305  may be an example of aspects of a wireless device  1205  or a base station  105  as described with reference to  FIGS.  1  and  12   . Wireless device  1305  may include receiver  1310 , base station autonomous uplink manager  1315 , and transmitter  1320 . Wireless device  1305  may also  include a processor. Each of these components may be in communication with one another (e.g., via one or more buses). 
     Receiver  1310  may 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 autonomous uplink transmission techniques using shared radio frequency spectrum, etc.). Information may be passed on to other components of the device. The receiver  1310  may be an example of aspects of the transceiver  1535  described with reference to  FIG.  15   . 
     Base station autonomous uplink manager  1315  may be an example of aspects of the base station autonomous uplink manager  1515  described with reference to  FIG.  15   . Base station autonomous uplink manager  1315  may also include autonomous uplink configuration manager  1325 , AUL channel access manager  1330 , data manager  1335 , AUL activation component  1340 , and control information component  1345 . 
     Autonomous uplink configuration manager  1325  may configure a UE for autonomous uplink transmissions in a shared radio frequency spectrum band and transmit RRC signaling to a UE that includes an autonomous uplink configuration for unscheduled autonomous uplink transmissions in a shared radio frequency spectrum band. 
     AUL channel access manager  1330  may receive an autonomous uplink transmission from the UE over the shared radio frequency spectrum band, the autonomous uplink transmission including one or more channel access parameters. In some cases, the channel access parameters include a number of subframes available for downlink transmissions based on a time difference between uplink transmissions and a MCOT acquired by the UE. In some cases, the base station may transmit one or more transmissions during the time difference, and transmissions to one or more UEs other than the UE that acquired the MCOT are precluded during the time difference. 
     Data manager  1335  may transmit a downlink transmission over the shared radio frequency spectrum band in accordance with one or more of the channel access parameters. 
     AUL activation component  1340  may determine that the autonomous uplink transmissions should be activated for the UE and determine that that the autonomous uplink transmissions should be deactivated for the UE.  
     Control information component  1345  may transmit DCI that activates autonomous uplink transmissions responsive to determining that the autonomous uplink transmissions should be activated for the UE and transmit DCI that deactivates the autonomous uplink transmissions responsive to determining that the autonomous uplink transmissions should be deactivated for the UE. In some cases, the autonomous uplink transmission includes uplink control information including one or more of a HARQ identification, a burst length of the uplink transmission, a MCOT, a RV indication, a NDI, or an AUL-RNTI. In some cases, the downlink transmission includes A-DCI associated with one or more autonomous uplink transmissions. In some cases, the DCI includes a CRC field scrambled with an AUL-RNTI for the UE, and where a value of the AUL-RNTI indicates whether autonomous uplink transmissions are activated or deactivated. 
     Transmitter  1320  may transmit signals generated by other components of the device. In some examples, the transmitter  1320  may be collocated with a receiver  1310  in a transceiver module. For example, the transmitter  1320  may be an example of aspects of the transceiver  1535  described with reference to  FIG.  15   . The transmitter  1320  may include a single antenna, or it may include a set of antennas. 
       FIG.  14    shows a block diagram  1400  of a base station autonomous uplink manager  1415  that supports autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with various aspects of the present disclosure. The base station autonomous uplink manager  1415  may be an example of aspects of a base station autonomous uplink manager  1515  described with reference to  FIGS.  12 ,  13 , and  15   . The base station autonomous uplink manager  1415  may include autonomous uplink configuration manager  1420 , AUL channel access manager  1425 , data manager  1430 , AUL activation component  1435 , control information component  1440 , HARQ manager  1445 , and MIMO manager  1450 . Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses). 
     Autonomous uplink configuration manager  1420  may configure a UE for autonomous uplink transmissions in a shared radio frequency spectrum band and transmit RRC signaling to a UE that includes an autonomous uplink configuration for unscheduled autonomous uplink transmissions in a shared radio frequency spectrum band. 
     AUL channel access manager  1425  may receive an autonomous uplink transmission from the UE over the shared radio frequency spectrum band, the autonomous  uplink transmission including one or more channel access parameters. In some cases, the channel access parameters include a number of subframes available for downlink transmissions based on a time difference between uplink transmissions and a MCOT acquired by the UE. In some cases, the base station may transmit one or more transmissions during the time difference, and transmissions to one or more UEs other than the UE that acquired the MCOT are precluded during the time difference. 
     Data manager  1430  may transmit a downlink transmission over the shared radio frequency spectrum band in accordance with one or more of the channel access parameters. 
     AUL activation component  1435  may determine that the autonomous uplink transmissions should be activated for the UE and determine that that the autonomous uplink transmissions should be deactivated for the UE. 
     Control information component  1440  may transmit DCI that activates autonomous uplink transmissions responsive to determining that the autonomous uplink transmissions should be activated for the UE and transmit DCI that deactivates the autonomous uplink transmissions responsive to determining that the autonomous uplink transmissions should be deactivated for the UE. In some cases, the autonomous uplink transmission includes uplink control information including one or more of a HARQ identification, a burst length of the uplink transmission, a MCOT, a RV indication, a NDI, or an AUL-RNTI. In some cases, the downlink transmission includes A-DCI associated with one or more autonomous uplink transmissions. In some cases, the DCI includes a CRC field scrambled with an AUL-RNTI for the UE, and where a value of the AUL-RNTI indicates whether autonomous uplink transmissions are activated or deactivated. 
     HARQ manager  1445  may perform HARQ feedback processing. In some cases, the A-DCI includes one or more of a bitmap of feedback information associated with one or more feedback processes associated with one or more autonomous uplink transmission, one or more ACK/NACK indications, or uplink power control information. In some cases, the bits from two or more feedback processes are bundled. 
     MIMO manager  1450  may enable autonomous uplink transmissions on one or more transmit antennas according to a multiple input multiple output (MIMO) configuration. 
       FIG.  15    shows a diagram of a system  1500  including a device  1505  that supports autonomous uplink transmission techniques using shared radio frequency spectrum in  accordance with various aspects of the present disclosure. Device  1505  may be an example of or include the components of base station  105  as described above, e.g., with reference to  FIG.  1   . Device  1505  may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including base station autonomous uplink manager  1515 , processor  1520 , memory  1525 , software  1530 , transceiver  1535 , antenna  1540 , network communications manager  1545 , and base station communications manager  1550 . These components may be in electronic communication via one or more busses (e.g., bus  1510 ). Device  1505  may communicate wirelessly with one or more UEs  115 . 
     Processor  1520  may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, processor  1520  may be configured to operate a memory array using a memory controller. In other cases, a memory controller may be integrated into processor  1520 . Processor  1520  may be configured to execute computer-readable instructions stored in a memory to perform various functions (e.g., functions or tasks supporting autonomous uplink transmission techniques using shared radio frequency spectrum). 
     Memory  1525  may include RAM and ROM. The memory  1525  may store computer-readable, computer-executable software  1530  including instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory  1525  may contain, among other things, a BIOS which may control basic hardware and/or software operation such as the interaction with peripheral components or devices. 
     Software  1530  may include code to implement aspects of the present disclosure, including code to support autonomous uplink transmission techniques using shared radio frequency spectrum. Software  1530  may be stored in a non-transitory computer-readable medium such as system memory or other memory. In some cases, the software  1530  may not be directly executable by the processor but may cause a computer (e.g., when compiled and executed) to perform functions described herein. 
     Transceiver  1535  may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver  1535  may represent  a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver  1535  may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas. 
     In some cases, the wireless device may include a single antenna  1540 . However, in some cases the device may have more than one antenna  1540 , which may be capable of concurrently transmitting or receiving multiple wireless transmissions. 
     Network communications manager  1545  may manage communications with the core network (e.g., via one or more wired backhaul links). For example, the network communications manager  1545  may manage the transfer of data communications for client devices, such as one or more UEs  115 . 
     Base station communications manager  1550  may manage communications with other base station  105 , and may include a controller or scheduler for controlling communications with UEs  115  in cooperation with other base stations  105 . For example, the base station communications manager  1550  may coordinate scheduling for transmissions to UEs  115  for various interference mitigation techniques such as beamforming or joint transmission. In some examples, base station communications manager  1550  may provide an X2 interface within an Long Term Evolution (LTE)/LTE-A wireless communication network technology to provide communication between base stations  105 . 
       FIG.  16    shows a flowchart illustrating a method  1600  for autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with various aspects of the present disclosure. The operations of method  1600  may be implemented by a UE  115  or its components as described herein. For example, the operations of method  1600  may be performed by a UE autonomous uplink manager as described with reference to  FIGS.  8  through  11   . In some examples, a UE  115  may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the UE  115  may perform aspects of the functions described below using special-purpose hardware. 
     At block  1605  the UE  115  may contend for access to a channel of a shared radio frequency spectrum band in accordance with an autonomous uplink configuration which indicates a transmission window available for autonomous uplink transmissions. The operations of block  1605  may be performed according to the methods described with  reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  1605  may be performed by a LBT manager as described with reference to  FIGS.  8  through  11   . 
     At block  1610  the UE  115  may determine one or more channel access parameters based at least in part on one or more of a duration of an uplink transmission to be transmitted over the channel of the shared radio frequency spectrum band or a TA for the uplink transmission. The operations of block  1610  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  1610  may be performed by a control information component as described with reference to  FIGS.  8  through  11   . 
     At block  1615  the UE  115  may transmit the uplink transmission over the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration, wherein the uplink transmission indicates one or more of the channel access parameters. The operations of block  1615  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  1615  may be performed by a data manager as described with reference to  FIGS.  8  through  11   . 
       FIG.  17    shows a flowchart illustrating a method  1700  for autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with various aspects of the present disclosure. The operations of method  1700  may be implemented by a UE  115  or its components as described herein. For example, the operations of method  1700  may be performed by a UE autonomous uplink manager as described with reference to  FIGS.  8  through  11   . In some examples, a UE  115  may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the UE  115  may perform aspects of the functions described below using special-purpose hardware. 
     At block  1705  the UE  115  may contend for access to a channel of a shared radio frequency spectrum band in accordance with an autonomous uplink configuration which indicates a transmission window available for autonomous uplink transmissions. The operations of block  1705  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  1705  may be performed by a LBT manager as described with reference to  FIGS.  8  through  11   .  
     At block  1710  the UE  115  may determine one or more channel access parameters based at least in part on one or more of a duration of an uplink transmission to be transmitted over the channel of the shared radio frequency spectrum band or a TA for the uplink transmission. The operations of block  1710  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  1710  may be performed by a control information component as described with reference to  FIGS.  8  through  11   . 
     At block  1715  the UE  115  may modify a waveform of the uplink transmission based at least in part on the TA. The operations of block  1715  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  1715  may be performed by a data manager as described with reference to  FIGS.  8  through  11   . 
     At block  1720  the UE  115  may transmit the uplink transmission over the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration, wherein the uplink transmission indicates one or more of the channel access parameters. The operations of block  1720  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  1720  may be performed by a data manager as described with reference to  FIGS.  8  through  11   . 
       FIG.  18    shows a flowchart illustrating a method  1800  for autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with various aspects of the present disclosure. The operations of method  1800  may be implemented by a UE  115  or its components as described herein. For example, the operations of method  1800  may be performed by a UE autonomous uplink manager as described with reference to  FIGS.  8  through  11   . In some examples, a UE  115  may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the UE  115  may perform aspects of the functions described below using special-purpose hardware. 
     At block  1805  the UE  115  may contend for access to a channel of a shared radio frequency spectrum band in accordance with an autonomous uplink configuration which indicates a transmission window available for autonomous uplink transmissions. The operations of block  1805  may be performed according to the methods described with  reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  1805  may be performed by a LBT manager as described with reference to  FIGS.  8  through  11   . 
     At block  1810  the UE  115  may determine one or more channel access parameters based at least in part on one or more of a duration of an uplink transmission to be transmitted over the channel of the shared radio frequency spectrum band or a TA for the uplink transmission. The operations of block  1810  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  1810  may be performed by a control information component as described with reference to  FIGS.  8  through  11   . 
     At block  1815  the UE  115  may identify a time for starting a subsequent downlink transmission following the uplink transmission. The operations of block  1815  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  1815  may be performed by a timing gap component as described with reference to  FIGS.  8  through  11   . 
     At block  1820  the UE  115  may format the uplink transmission to occupy the channel of the shared radio frequency spectrum band until the time for starting the subsequent downlink transmission, wherein a transmitter of the subsequent downlink transmission performs a CCA to occupy a maximum time gap between the uplink transmission and the subsequent downlink transmission. The operations of block  1820  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  1820  may be performed by a timing gap component as described with reference to  FIGS.  8  through  11   . 
     At block  1825  the UE  115  may transmit the uplink transmission over the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration, wherein the uplink transmission indicates one or more of the channel access parameters. The operations of block  1825  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  1825  may be performed by a data manager as described with reference to  FIGS.  8  through  11   . 
       FIG.  19    shows a flowchart illustrating a method  1900  for autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with various aspects of the present disclosure. The operations of method  1900  may be implemented by a  UE  115  or its components as described herein. For example, the operations of method  1900  may be performed by a UE autonomous uplink manager as described with reference to  FIGS.  8  through  11   . In some examples, a UE  115  may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the UE  115  may perform aspects of the functions described below using special-purpose hardware. 
     At block  1905  the UE  115  may contend for access to a channel of a shared radio frequency spectrum band in accordance with an autonomous uplink configuration which indicates a transmission window available for autonomous uplink transmissions. The operations of block  1905  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  1905  may be performed by a LBT manager as described with reference to  FIGS.  8  through  11   . 
     At block  1910  the UE  115  may determine one or more channel access parameters based at least in part on one or more of a duration of an uplink transmission to be transmitted over the channel of the shared radio frequency spectrum band or a TA for the uplink transmission. The operations of block  1910  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  1910  may be performed by a control information component as described with reference to  FIGS.  8  through  11   . 
     At block  1915  the UE  115  may transmit the uplink transmission over the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration, wherein the uplink transmission indicates one or more of the channel access parameters. The operations of block  1915  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  1915  may be performed by a data manager as described with reference to  FIGS.  8  through  11   . 
     At block  1920  the UE  115  may transmit a time difference between a MCOT and a duration of the uplink transmission to a base station, wherein the base station may transmit one or more transmissions during the time difference and one or more other transmitters are precluded from transmitting during the time difference. The operations of block  1920  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain  examples, aspects of the operations of block  1920  may be performed by a timing gap component as described with reference to  FIGS.  8  through  11   . 
       FIG.  20    shows a flowchart illustrating a method  2000  for autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with various aspects of the present disclosure. The operations of method  2000  may be implemented by a UE  115  or its components as described herein. For example, the operations of method  2000  may be performed by a UE autonomous uplink manager as described with reference to  FIGS.  8  through  11   . In some examples, a UE  115  may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the UE  115  may perform aspects of the functions described below using special-purpose hardware. 
     At block  2005  the UE  115  may contend for access to a channel of a shared radio frequency spectrum band in accordance with an autonomous uplink configuration which indicates a transmission window available for autonomous uplink transmissions. The operations of block  2005  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2005  may be performed by a LBT manager as described with reference to  FIGS.  8  through  11   . 
     At block  2010  the UE  115  may determine one or more channel access parameters based at least in part on one or more of a duration of an uplink transmission to be transmitted over the channel of the shared radio frequency spectrum band or a TA for the uplink transmission. The operations of block  2010  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2010  may be performed by a control information component as described with reference to  FIGS.  8  through  11   . 
     At block  2015  the UE  115  may transmit the uplink transmission over the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration, wherein the uplink transmission indicates one or more of the channel access parameters. The operations of block  2015  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2015  may be performed by a data manager as described with reference to  FIGS.  8  through  11   .  
     At block  2020  the UE  115  may determine that additional data is to be transmitted following the transmission window. The operations of block  2020  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2020  may be performed by a data manager as described with reference to  FIGS.  8  through  11   . 
     At block  2025  the UE  115  may transmit one or more subsequent uplink transmissions after the uplink transmission outside of the transmission window when a MCOT is determined as part of the contending for access to the channel of the shared radio frequency spectrum band. The operations of block  2025  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2025  may be performed by a data manager as described with reference to  FIGS.  8  through  11   . 
       FIG.  21    shows a flowchart illustrating a method  2100  for autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with various aspects of the present disclosure. The operations of method  2100  may be implemented by a UE  115  or its components as described herein. For example, the operations of method  2100  may be performed by a UE autonomous uplink manager as described with reference to  FIGS.  8  through  11   . In some examples, a UE  115  may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the UE  115  may perform aspects of the functions described below using special-purpose hardware. 
     At block  2105  the UE  115  may receive RRC signaling including an autonomous uplink configuration for unscheduled autonomous uplink transmissions in a shared radio frequency spectrum band. The operations of block  2105  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2105  may be performed by an autonomous uplink configuration manager as described with reference to  FIGS.  8  through  11   . 
     At block  2110  the UE  115  may receive DCI that activates autonomous uplink transmissions. The operations of block  2110  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2110  may be performed by a control information component as described with reference to  FIGS.  8  through  11   .  
     At block  2115  the UE  115  may contend for access to a channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration. The operations of block  2115  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2115  may be performed by a LBT manager as described with reference to  FIGS.  8  through  11   . 
     At block  2120  the UE  115  may transmit one or more autonomous uplink transmissions over the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration. The operations of block  2120  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2120  may be performed by a data manager as described with reference to  FIGS.  8  through  11   . 
     At optional block  2125  the UE  115  may receive subsequent DCI that deactivates autonomous uplink transmissions. The operations of block  2125  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2125  may be performed by a control information component as described with reference to  FIGS.  8  through  11   . 
     At optional block  2130  the UE  115  may discontinue contending for access to the channel of the shared radio frequency spectrum band responsive to the receiving the subsequent DCI that deactivates autonomous uplink transmissions. The operations of block  2130  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2130  may be performed by a data manager as described with reference to  FIGS.  8  through  11   . 
       FIG.  22    shows a flowchart illustrating a method  2200  for autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with various aspects of the present disclosure. The operations of method  2200  may be implemented by a UE  115  or its components as described herein. For example, the operations of method  2200  may be performed by a UE autonomous uplink manager as described with reference to  FIGS.  8  through  11   . In some examples, a UE  115  may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the UE  115  may perform aspects of the functions described below using special-purpose hardware.  
     At block  2205  the UE  115  may identify an autonomous uplink configuration for unscheduled uplink transmissions in a shared radio frequency spectrum band. The operations of block  2205  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2205  may be performed by an autonomous uplink configuration manager as described with reference to  FIGS.  8  through  11   . 
     At block  2210  the UE  115  may contend for access to a channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration. The operations of block  2210  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2210  may be performed by a LBT manager as described with reference to  FIGS.  8  through  11   . 
     At block  2215  the UE  115  may determine uplink control information and uplink shared channel information for an uplink transmission to be transmitted over the channel of the shared radio frequency spectrum band. The operations of block  2215  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2215  may be performed by a control information component as described with reference to  FIGS.  8  through  11   . 
     At block  2220  the UE  115  may rate match the uplink shared channel information around the uplink control information in the uplink transmission. The operations of block  2220  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2220  may be performed by a data manager as described with reference to  FIGS.  8  through  11   . 
     At block  2225  the UE  115  may transmit the uplink transmission over the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration. The operations of block  2225  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2225  may be performed by a data manager as described with reference to  FIGS.  8  through  11   . 
       FIG.  23    shows a flowchart illustrating a method  2300  for autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with various aspects of the present disclosure. The operations of method  2300  may be implemented by a UE  115  or its components as described herein. For example, the operations of method  2300   may be performed by a UE autonomous uplink manager as described with reference to  FIGS.  8  through  11   . In some examples, a UE  115  may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the UE  115  may perform aspects of the functions described below using special-purpose hardware. 
     At block  2305  the UE  115  may identify an autonomous uplink configuration for unscheduled uplink transmissions in a shared radio frequency spectrum band. The operations of block  2305  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2305  may be performed by an autonomous uplink configuration manager as described with reference to  FIGS.  8  through  11   . 
     At block  2310  the UE  115  may receive A-DCI associated with one or more autonomous uplink transmissions. The operations of block  2310  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2310  may be performed by a control information component as described with reference to  FIGS.  8  through  11   . 
     At block  2315  the UE  115  may transmit an autonomous uplink transmission over the shared radio frequency spectrum band in accordance with the autonomous uplink configuration and the A-DCI. The operations of block  2315  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2315  may be performed by a data manager as described with reference to  FIGS.  8  through  11   . 
       FIG.  24    shows a flowchart illustrating a method  2400  for autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with various aspects of the present disclosure. The operations of method  2400  may be implemented by a base station  105  or its components as described herein. For example, the operations of method  2400  may be performed by a base station autonomous uplink manager as described with reference to  FIGS.  12  through  15   . In some examples, a base station  105  may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the base station  105  may perform aspects of the functions described below using special-purpose hardware.  
     At block  2405  the base station  105  may configure a UE for autonomous uplink transmissions in a shared radio frequency spectrum band. The operations of block  2405  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2405  may be performed by an autonomous uplink configuration manager as described with reference to  FIGS.  12  through  15   . 
     At block  2410  the base station  105  may receive an autonomous uplink transmission from the UE over the shared radio frequency spectrum band, the autonomous uplink transmission including one or more channel access parameters. The operations of block  2410  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2410  may be performed by a AUL channel access manager as described with reference to  FIGS.  12  through  15   . 
     At block  2415  the base station  105  may transmit a downlink transmission over the shared radio frequency spectrum band in accordance with one or more of the channel access parameters. The operations of block  2415  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2415  may be performed by a data manager as described with reference to  FIGS.  12  through  15   . 
       FIG.  25    shows a flowchart illustrating a method  2500  for autonomous uplink transmission techniques using shared radio frequency spectrum in accordance with various aspects of the present disclosure. The operations of method  2500  may be implemented by a base station  105  or its components as described herein. For example, the operations of method  2500  may be performed by a base station autonomous uplink manager as described with reference to  FIGS.  12  through  15   . In some examples, a base station  105  may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the base station  105  may perform aspects of the functions described below using special-purpose hardware. 
     At block  2505  the base station  105  may transmit RRC signaling to a UE that includes an autonomous uplink configuration for unscheduled autonomous uplink transmissions in a shared radio frequency spectrum band. The operations of block  2505  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2505  may be performed by an  autonomous uplink configuration manager as described with reference to  FIGS.  12  through  15   . 
     At block  2510  the base station  105  may determine that the autonomous uplink transmissions should be activated for the UE. The operations of block  2510  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2510  may be performed by a AUL activation component as described with reference to  FIGS.  12  through  15   . 
     At block  2515  the base station  105  may transmit DCI that activates autonomous uplink transmissions responsive to determining that the autonomous uplink transmissions should be activated for the UE. The operations of block  2515  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2515  may be performed by a control information component as described with reference to  FIGS.  12  through  15   . 
     At block  2520  the base station  105  may receive one or more autonomous uplink transmissions over the channel of the shared radio frequency spectrum band in accordance with the autonomous uplink configuration. The operations of block  2520  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2520  may be performed by a receiver as described with reference to  FIGS.  12  through  15   . 
     At block  2525  the base station  105  may determine that that the autonomous uplink transmissions should be deactivated for the UE. The operations of block  2525  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2525  may be performed by a AUL activation component as described with reference to  FIGS.  12  through  15   . 
     At block  2530  the base station  105  may transmit DCI that deactivates the autonomous uplink transmissions responsive to determining that the autonomous uplink transmissions should be deactivated for the UE. The operations of block  2530  may be performed according to the methods described with reference to  FIGS.  1  through  7   . In certain examples, aspects of the operations of block  2530  may be performed by a control information component as described with reference to  FIGS.  12  through  15   .  
     It should be noted that the methods described above describe possible implementations, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible. Furthermore, aspects from two or more of the methods may be combined. 
     Techniques described herein may be used for various wireless communications 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 may implement a radio technology such as CDMA2000, Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000 Releases may be commonly referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. A time division multiple access (TDMA) system may implement a radio technology such as Global System for Mobile Communications (GSM). 
     An orthogonal frequency division multiple access (OFDMA) system may implement a radio technology such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunications system (UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are releases of Universal Mobile Telecommunications System (UMTS) that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, NR, and Global System for Mobile communications (GSM) are described in documents from the organization named “3rd Generation Partnership Project” (3GPP). CDMA2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2). The techniques described herein may be used for the systems and radio technologies mentioned above as well as other systems and radio technologies. While aspects an LTE or an NR system may be described for purposes of example, and LTE or NR terminology may be used in much of the description, the techniques described herein are applicable beyond LTE or NR applications.  
     In LTE/LTE-A networks, including such networks described herein, the term evolved node B (eNB) may be generally used to describe the base stations. The wireless communications system or systems described herein may include a heterogeneous LTE/LTE-A or NR network in which different types of evolved node B (eNBs) provide coverage for various geographical regions. For example, each eNB, gNB or base station may provide communication coverage for a macro cell, a small cell, or other types of cell. The term “cell” may be used to describe a base station, a carrier or component carrier associated with a base station, or a coverage area (e.g., sector, etc.) of a carrier or base station, depending on context. 
     Base stations 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 NodeB, eNodeB (eNB), next generation NodeB (gNB), Home NodeB, a Home eNodeB, or some other suitable terminology. The geographic coverage area for a base station may be divided into sectors making up a portion of the coverage area. The wireless communications system or systems described herein may include base stations of different types (e.g., macro 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, gNBs, relay base stations, and the like. There may be overlapping geographic coverage areas for different technologies. 
     A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions with the network provider. A small cell is a lower-powered base station, as compared with a macro cell, that may operate in the same or different (e.g., licensed, unlicensed, etc.) frequency bands as macro cells. Small cells may include pico cells, femto cells, and micro cells according to various examples. A pico cell, for example, may cover a small geographic area and may allow unrestricted access by UEs with service subscriptions with the network provider. A femto cell may also cover a small geographic area (e.g., a home) and may provide restricted access by UEs having an association with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs for users in the home, and the like). 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 multiple (e.g., two, three, four, and the like) cells (e.g., component carriers).  
     The wireless communications system or systems described herein may support synchronous or asynchronous operation. For synchronous operation, the base stations may have similar frame timing, and transmissions from different base stations may be approximately aligned in time. For asynchronous operation, the 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 operations. 
     The downlink transmissions described herein may also be called forward link transmissions while the uplink transmissions may also be called reverse link transmissions. Each communication link described herein—including, for example, wireless communications system  100  and  200  of  FIGS.  1  and  2   —may include one or more carriers, where each carrier may be a signal made up of multiple sub-carriers (e.g., waveform signals of different frequencies). 
     The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term “exemplary” used herein means “serving as an example, instance, or illustration,” and not “preferred” or “advantageous over other examples.” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples. 
     In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label. 
     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 referenced throughout the above  description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof. 
     The various illustrative blocks and modules described in connection with the disclosure herein may be implemented or performed 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. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration). 
     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, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described above can be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations. Also, as used herein, including in the claims, “or” as used in a list of items (for example, a list of items prefaced by a phrase such as “at least one of” or “one or more of”) indicates an inclusive list such that, for example, a list 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). Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an exemplary step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on.” 
     Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available  medium that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media may comprise RAM, ROM, electrically erasable programmable read only memory (EEPROM), compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the 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 microwave, then the coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc 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. 
     The description herein is provided to enable a person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein, but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.