Uplink short transmission method and apparatus using contention-based radio frequency spectrum

Abstract

Disclosed are methods and apparatus for uplink short transmissions using contention-based radio frequency spectrum. An uplink short transmission (ULST) can be configured in a wireless communication system to be transmitted in configured uplink resources within a listen-before-talk (LBT) frame or within a ULST window, during which a user equipment (UE) can transmit a ULST and a base station can monitor the ULST. A UE with a data volume to transmit that is less than a threshold can transmit the data in the ULST, obviating the need for the base station to allocate separate uplink resources outside of these configured uplink resources or the ULST window.

Description

[0001] This application is a divisional application of a Chinese patent application filed on January 20, 2017, with application number 201780009190.5 (international application number PCT / US2017 / 014396), and invention name “Uplink short transmission technology using contention-based radio frequency spectrum”.

[0002] Cross-references

[0003] This patent application claims priority to U.S. patent application No. 15 / 410,640, filed by Mallik et al. on January 19, 2017, entitled “Uplink Short Transmission Techniques Using Contention-Based Radio Frequency Spectrum,” and U.S. Provisional Patent Application No. 62 / 290,094, filed by Mallik et al. on February 2, 2016, entitled “Uplink Short Transmission Techniques UsingContention-Based Radio Frequency Spectrum,” each of which is assigned to the assignee of this application. Technical Field

[0004] The following relates generally to wireless communications and, more particularly, to uplink short transmission (ULST) techniques using contention-based radio frequency spectrum. Background Art

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

[0006] Some communication modes enable communication between a base station and a UE in a shared RF spectrum band or in different RF spectrum bands of a cellular network (e.g., a licensed RF spectrum band and a shared RF spectrum band). However, in contrast to carriers in a licensed RF spectrum band that may be allocated for use by devices in a public land mobile network (PLMN) and available to a base station or UE of the PLMN at predetermined (or all) times, carriers in a shared RF spectrum band may be intermittently available to devices in the PLMN. This intermittent availability may be the result of contention for access to carriers in the shared RF spectrum band between devices in the PLMN, devices in one or more other PLMNs, and / or other devices (e.g., Wi-Fi devices). For some radio frames, a device in the PLMN may win contention for access to a carrier in the shared RF spectrum band, while for other radio frames, the device may not win contention for access to a carrier in the shared RF spectrum band. Devices may contend for access to a shared RF spectrum band using a listen-before-talk (LBT) procedure, in which a device may monitor the shared RF spectrum band to confirm that another device is not using the medium for transmission before initiating a transmission.

[0007] In some cases, a UE may have uplink data to transmit to a base station and may transmit a scheduling request (SR) or a random access channel (RACH) request to request that uplink resources be allocated to the UE for transmission of the uplink data. Due to the intermittent availability of carriers in a shared radio frequency spectrum band, the UE may have to contend for access to a carrier in the shared radio frequency spectrum band on multiple occasions, the first time to transmit the SR or RACH request and again to transmit using the resources allocated for transmission of the uplink data. Reducing the need for the base station to allocate uplink transmission resources and reducing the need for the UE to have to contend for access to carriers in a shared radio frequency spectrum band can enhance the efficiency of devices operating using the shared radio frequency spectrum band. Summary of the Invention

[0008] The present disclosure relates, for example, to wireless communication systems and, more particularly, to uplink short transmission (ULST) techniques using contention-based radio frequency spectrum. As previously indicated, in some situations, it may be desirable to reduce the need for a base station to allocate uplink transmission resources, and to reduce the need for user equipment (UE) to have to contend for access to a carrier in a shared radio frequency spectrum band. Various aspects of the present disclosure provide techniques for identifying a ULST, wherein a relatively small amount of data from a UE can be transmitted directly to a base station just after the UE wins contention for a carrier in a shared radio frequency spectrum band.

[0009] In some aspects of the present disclosure, a base station may configure uplink resources for ULST from one or more UEs within a listen-before-talk (LBT) frame. A UE with an amount of data to be transmitted that is less than a threshold may transmit the data in a ULST and avoid the need for the base station to allocate separate uplink resources for the transmission. The base station may also configure a ULST window during which the UE may transmit a ULST and during which the base station may monitor each ULST. In some examples, the ULST window may be configured so that the UE does not transmit a ULST during an LBT frame. In some cases, the base station may configure a timer for the UE, and the UE may start the timer in response to data arriving at the UE for uplink transmission and monitor downlink transmissions until the timer expires. In some cases, the downlink transmission may include a downlink preamble that may be used to determine the uplink resources for the ULST transmission within the associated LBT frame. In other cases, the UE may not detect the downlink preamble before the timer expires, in which case the UE may initiate an LBT procedure for the ULST during the configured ULST window.

[0010] A method of wireless communication is described. The method may include identifying data to be transmitted to a base station; monitoring one or more downlink transmissions from the base station; determining scheduled uplink resources for uplink transmissions associated with the identified data based at least in part on detecting the one or more downlink transmissions from the base station; and initiating an LBT procedure for the uplink transmission associated with the identified data during a ULST window if the one or more downlink transmissions from the base station are not detected within a specified time period.

[0011] An apparatus for wireless communication is described. The apparatus may include: means for identifying data to be transmitted to a base station; means for monitoring one or more downlink transmissions from the base station; means for determining scheduled uplink resources for uplink transmissions associated with the identified data based at least in part on detecting the one or more downlink transmissions from the base station; and means for initiating an LBT procedure for the uplink transmission associated with the identified data during a ULST window if one or more downlink transmissions from the base station are not detected within a specified time period.

[0012] Another apparatus is described. The apparatus may include a processor, a memory in electronic communication with the processor, and instructions stored in the memory. The instructions are operable to cause the processor to: identify data to be transmitted to a base station; monitor one or more downlink transmissions from the base station; determine scheduled uplink resources for uplink transmissions associated with the identified data based at least in part on detecting the one or more downlink transmissions from the base station; and initiate an LBT procedure for the uplink transmission associated with the identified data during a ULST window if the one or more downlink transmissions from the base station are not detected within a specified time period.

[0013] A non-transitory computer-readable medium for wireless communication is described. The non-transitory computer-readable medium may include instructions for causing a processor to: identify data to be transmitted to a base station; monitor one or more downlink transmissions from the base station; determine scheduled uplink resources for uplink transmissions associated with the identified data based on detecting the one or more downlink transmissions from the base station; and initiate an LBT procedure for the uplink transmission associated with the identified data during a ULST window if the one or more downlink transmissions from the base station are not detected within a specified time period.

[0014] Some examples of the above methods, devices (apparatus), or non-transitory computer-readable media may further include a process, feature, means, or instruction for the following operations: starting a timer upon identifying data to be transmitted to a base station. Some examples of the above methods, devices (apparatus), or non-transitory computer-readable media may further include a process, feature, means, or instruction for the following operations: terminating the timer in response to detecting one or more downlink transmissions from the base station, and wherein the LBT procedure is initiated during the ULST window in response to expiration of the timer.

[0015] In some examples of the above method, apparatus, or non-transitory computer-readable medium, monitoring one or more downlink transmissions includes monitoring a downlink preamble associated with an LBT frame. In some examples of the above method, apparatus, or non-transitory computer-readable medium, the scheduled uplink resources are determined based on the downlink preamble.

[0016] In some examples of the foregoing method, apparatus, or non-transitory computer-readable medium, the scheduled uplink resources include resources of an uplink subframe associated with an LTB frame. In some examples of the foregoing method, apparatus, or non-transitory computer-readable medium, the scheduled uplink resources include one or more of semi-statically configured uplink resources of one or more uplink subframes of an LBT frame, predefined uplink resources of a first uplink subframe of an LBT frame, or dynamically configured resources identified in a downlink preamble.

[0017] In some examples of the above method, apparatus, or non-transitory computer-readable medium, initiating the LBT procedure further includes identifying resources within a ULST window for transmitting an uplink transmission associated with the identified data. In some examples of the above method, apparatus, or non-transitory computer-readable medium, the resources within the ULST window for transmitting an uplink transmission associated with the identified data are semi-statically configured resources.

[0018] In some examples of the foregoing method, apparatus, or non-transitory computer-readable medium, resources within the ULST window for transmitting uplink transmissions associated with the identified data are received in a system information block (SIB) from the base station. In some examples of the foregoing method, apparatus, or non-transitory computer-readable medium, the ULST window is outside of an LBT frame.

[0019] In some examples of the foregoing methods, apparatus, or non-transitory computer-readable media, the uplink transmission associated with the identified data includes a scheduling request (SR) or a random access request to schedule uplink resources for uplink transmission of the identified data.

[0020] Some examples of the above methods, devices, or non-transitory computer-readable media may further include a process, feature, means, or instruction for determining that the identified data is less than a size threshold. Some examples of the above methods, devices, or non-transitory computer-readable media may further include a process, feature, means, or instruction for including the identified data in an uplink transmission associated with the identified data.

[0021] A method of wireless communication is described. The method may include transmitting one or more downlink transmissions associated with an LBT frame to at least one UE, configuring an ULST window that does not overlap with the LBT frame, and monitoring uplink transmissions from one or more UEs during the ULST window.

[0022] An apparatus for wireless communication is described. The apparatus may include: means for transmitting one or more downlink transmissions associated with an LBT frame to at least one UE; means for configuring an ULST window that does not overlap with the LBT frame; and means for monitoring uplink transmissions from one or more UEs during the ULST window.

[0023] Another apparatus is described. The apparatus may include a processor, a memory in electronic communication with the processor, and instructions stored in the memory. The instructions are operable to cause the processor to: transmit one or more downlink transmissions associated with an LBT frame to at least one UE; configure an ULST window that does not overlap with the LBT frame; and monitor uplink transmissions from one or more UEs during the ULST window.

[0024] A non-transitory computer-readable medium for wireless communication is described. The non-transitory computer-readable medium may include instructions for causing a processor to: transmit one or more downlink transmissions associated with an LBT frame to at least one UE; configure an ULST window that does not overlap with the LBT frame; and monitor uplink transmissions from one or more UEs during the ULST window.

[0025] Some examples of the above method, device (apparatus), or non-transitory computer-readable medium may further include a process, feature, means, or instruction for the following operations: configuring the one or more UEs with a timer for monitoring the one or more downlink transmissions. Some examples of the above method, device (apparatus), or non-transitory computer-readable medium may further include a process, feature, means, or instruction for the following operations: configuring the one or more UEs to initiate an uplink transmission during the ULST window if the one or more downlink transmissions are not detected before expiration of the timer.

[0026] Some examples of the above method, device (apparatus), or non-transitory computer-readable medium may further include a process, feature, means, or instruction for scheduling uplink resources in one or more uplink subframes of the LBT frame. Some examples of the above method, device (apparatus), or non-transitory computer-readable medium may further include a process, feature, means, or instruction for configuring the one or more UEs to transmit an uplink transmission during the scheduled uplink resources upon detecting the one or more downlink transmissions before expiration of the timer.

[0027] In some examples of the foregoing method, apparatus, or non-transitory computer-readable medium, the one or more downlink transmissions include a downlink preamble, and wherein the scheduled uplink resources are determined based on the downlink preamble. In some examples of the foregoing method, apparatus, or non-transitory computer-readable medium, the scheduled uplink resources include resources of an uplink subframe associated with an LTB frame.

[0028] In some examples of the above-described methods, apparatus, or non-transitory computer-readable media, the scheduled uplink resources include one or more of semi-statically configured uplink resources of one or more uplink subframes of an LBT frame, predefined uplink resources of a first uplink subframe of an LBT frame, or dynamically configured resources identified in a downlink preamble.

[0029] In some examples of the above method, apparatus, or non-transitory computer-readable medium, configuring the ULST window includes configuring resources within the ULST window for uplink transmission. In some examples of the above method, apparatus, or non-transitory computer-readable medium, the resources within the ULST window for uplink transmission are semi-statically configured resources.

[0030] In some examples of the above method, apparatus, or non-transitory computer-readable medium, configuring the ULST window further comprises transmitting, to the one or more UEs, a SIB indicating the ULST window and resources configured for uplink transmission within the ULST window. In some examples of the above method, apparatus, or non-transitory computer-readable medium, the uplink transmission comprises one or more of an SR or a random access request to schedule uplink resources for one or more subsequent uplink transmissions.

[0031] Some examples of the above methods, devices (apparatuses), or non-transitory computer-readable media may further include processes, features, means, or instructions for configuring a size threshold for transmitting user data in an uplink transmission during a ULST window.

[0032] The foregoing has broadly outlined the features and technical advantages of examples according to the present disclosure in an effort to make the following detailed description better understood. Additional features and advantages will be described hereinafter. The concepts and specific examples disclosed can be readily used as a basis for modifying or designing other structures for implementing the same purposes as the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. The characteristics of the concepts disclosed herein, both in terms of their organization and method of operation, as well as the associated advantages, will be better understood by considering the following description in conjunction with the accompanying drawings. Each of the figures is provided for illustration and description purposes only and does not define limitations on the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] A further understanding of the nature and advantages of the present disclosure may be obtained by reference to the following drawings. In the drawings, similar components or functions may be given the same reference numerals. In addition, components of the same type may be distinguished by following the reference numeral with a dash and a second reference numeral to distinguish between similar components. If only the first reference numeral is used in the specification, the description applies to any of the similar components having the same first reference numeral, regardless of the second reference numeral.

[0034] Figure 1 An example of a wireless communication system supporting uplink short transmission (ULST) technology using contention-based radio frequency spectrum according to aspects of the present disclosure is illustrated;

[0035] Figure 2 An example of a wireless communication system supporting ULST technology using contention-based radio frequency spectrum according to aspects of the present disclosure is illustrated;

[0036] Figure 3 Illustrated are examples of configured uplink ULST resources for ULST periods, ULST windows, and LBT frames supporting ULST techniques using contention-based radio frequency spectrum in accordance with aspects of the present disclosure;

[0037] Figure 4 illustrates an example of a process flow in a system supporting ULST technology using contention-based radio frequency spectrum according to aspects of the present disclosure;

[0038] Figures 5 to 7 A block diagram illustrating a wireless device supporting ULST technology using contention-based radio frequency spectrum according to aspects of the present disclosure is shown;

[0039] Figure 8 illustrates a block diagram of a system including a UE supporting ULST technology using contention-based radio frequency spectrum in accordance with aspects of the present disclosure;

[0040] Figures 9 to 11 A block diagram illustrating a wireless device supporting ULST technology using contention-based radio frequency spectrum according to aspects of the present disclosure is shown;

[0041] Figure 12 A block diagram illustrating a system including a base station supporting ULST technology using contention-based radio frequency spectrum in accordance with aspects of the present disclosure; and

[0042] Figures 13 to 17 Methods for using ULST techniques based on contention-based radio frequency spectrum in accordance with aspects of the present disclosure are illustrated. DETAILED DESCRIPTION

[0043] Techniques are described in which shared radio frequency spectrum bands may be used for communications over a wireless communication system. In some examples, shared radio frequency spectrum bands may be used for Long Term Evolution (LTE) / LTE-Advanced (LTE-A) communications and may be shared with devices operating according to different radio access technologies (RATs), such as Wi-Fi devices operating according to, for example, the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard. Shared radio frequency spectrum bands may be used in combination with or independently of licensed radio frequency spectrum bands. Licensed radio frequency spectrum bands may include radio frequency spectrum bands for which transmitting devices may not contend for access (e.g., radio frequency spectrum bands that are licensed to specific users for specific uses, such as licensed radio frequency spectrum bands that can be used for LTE / LTE-A communications). Shared radio frequency spectrum bands may include radio frequency spectrum bands for which transmitting devices may contend for access using a listen-before-talk (LBT) procedure (e.g., radio frequency spectrum bands available for unlicensed use (such as Wi-Fi use), radio frequency spectrum bands available for use by different RATs, or radio frequency spectrum bands available for use by multiple operators in an equally shared or prioritized manner).

[0044] In some aspects of the present disclosure, a base station may configure uplink resources for uplink short transmissions (ULSTs) from one or more user equipment (UEs) within an LBT frame. The base station may also configure a ULST window during which the UE may transmit a ULST, and during which the base station may monitor for ULSTs, if the UE is unable to transmit a ULST during the configured uplink resources of the LBT frame.

[0045] In some examples, ULST may be used to transmit a relatively small amount of data from a UE. A UE with an amount of data to be transmitted that is less than a threshold value may transmit the data in the ULST and avoid the need for the base station to allocate a separate uplink resource for the transmission, and may also avoid the need for the UE to contend for access to a carrier of a shared radio frequency spectrum band at multiple times to transmit the data. In some examples, ULST may be used for a scheduling request (SR), a random access channel (RACH) request, a short data packet with an amount of data that is less than a threshold value, or a combination thereof. In some examples, an extended LBT procedure (e.g., a clear channel assessment (CCA) with a relatively large contention window) may be used before or after the ULST to provide other wireless nodes with an enhanced likelihood of winning contention for the shared radio frequency spectrum band.

[0046] The ULST window may be a configured window within the ULST period. In some examples, the ULST period may be associated with one or more system frame numbers (SFNs) and span the duration of one or more corresponding 10ms radio frames. In some examples, the ULST window may be configured as a portion of the ULST period, and the ratio of the duration of the ULST window to the periodicity defined by the ULST period may be a duty cycle of the ULST window. In some examples, the ULST duty cycle parameter may be configured by the base station and may be selected based at least in part on power consumption and potential uplink transmission delay.

[0047] In some examples, the UE may be configured such that the ULST window, in which the UE may contend for access and transmit a ULST, does not overlap with the LBT frame. In some cases, the base station may configure the UE with a timer, and the UE may start the timer in response to data arriving at the UE for uplink transmission. The UE may monitor the downlink transmission until the timer expires. In some cases, the downlink transmission may include a downlink preamble, which may be used to determine the uplink resources for the ULST transmission within the associated LBT frame. In other cases, the UE may not detect the downlink preamble before the timer expires, in which case the UE may initiate an LBT procedure for the ULST during the configured ULST window. The duration of the timer may be selected to provide that in the case where the ULST window starts during the LBT frame, the UE does not contend for access to the shared radio frequency spectrum band or transmit the ULST until after the LBT frame is completed.

[0048] In some examples, certain uplink resources of the LBT frame may be configured with uplink resources that can be used for ULST of one or more UEs. The uplink resources within the LBT frame may include, for example, the configured resources of the first uplink subframe of the LBT frame. In some cases, one or more downlink subframes of the LBT frame may include a downlink preamble that can be used to determine the allocated uplink resources of the uplink subframe of the LBT frame. In some examples, the duration of the timer configured at the UE may be selected to specify that the timer will expire after the last subframe of the LBT frame if the UE does not detect a downlink preamble, and thereby the UE is less likely to initiate a transmission that may interfere with the LBT frame.

[0049] Various aspects of the present disclosure are initially described in the context of a wireless communication system using a shared radio frequency spectrum band and an LBT protocol for accessing the shared radio frequency spectrum band. Various aspects of the present disclosure are further illustrated and described by and with reference to apparatus diagrams, system diagrams, and flow charts related to ULST technology for wireless transmission using a shared radio frequency spectrum band.

[0050] Figure 1 An example of a wireless communication system 100 according to various aspects of the present disclosure is illustrated. The wireless communication system 100 includes a base station 105, a UE 115, and a core network 130. In some examples, the wireless communication system 100 can be an LTE / LTE-A network. In some examples, the base station 105 can configure the UE 115 for ULST, and the UE 115 can identify ULST data and transmit the ULST in an allocated uplink resource within an LBT frame or after performing an LBT procedure during a ULST window outside of an LBT frame.

[0051] Base stations 105 can communicate wirelessly with UEs 115 via one or more base station antennas. Each base station 105 can provide communication coverage for a respective geographic coverage area 110. The communication links 125 shown in wireless communication system 100 can include uplink transmissions from UE 115 to base station 105, or downlink transmissions from base station 105 to UE 115. UEs 115 can be dispersed throughout wireless communication system 100, and each UE 115 can be stationary or mobile. UE 115 can also be referred to as a mobile station, subscriber station, remote unit, wireless device, access terminal (AT), handset, user agent, client, or similar terms. UE 115 can also be a cellular phone, a wireless modem, a handheld device, a personal computer, a tablet device, a personal electronic device, a machine type communication (MTC) device, or the like.

[0052] Each base station 105 can communicate with the core network 130 and with each other. For example, the base station 105 can interface with the core network 130 via a backhaul link 132 (e.g., S1, etc.). The base stations 105 can communicate with each other directly or indirectly (e.g., through the core network 130) on a backhaul link 134 (e.g., X2, etc.). The base station 105 can perform radio configuration and scheduling for communication with the UE 115, or can operate under the control of a base station controller (not shown). In some examples, the base station 105 can be a macro cell, a small cell, a hotspot, etc. The base station 105 can also be referred to as an evolved Node B (eNB) 105.

[0053] In some cases, the UE 115 or base station 105 may operate in a shared or unlicensed spectrum. These devices may perform LBT procedures (such as CCA) to determine whether the channel is available before communicating. CCA may include an energy detection procedure to determine whether there are any other active transmissions. For example, the device may infer that a change in the received signal strength indicator (RSSI) of the power meter indicates that the channel is occupied. Specifically, signal power concentrated in a certain bandwidth and exceeding a predetermined noise floor may indicate another wireless transmitter. CCA may also include detection of a specific sequence that indicates channel usage. For example, another device may transmit a specific preamble before transmitting a data sequence.

[0054] In some cases, the wireless communication system 100 may utilize one or more enhanced component carriers (eCCs). An eCC may be a non-backward compatible carrier characterized by a shorter symbol duration, longer subcarrier spacing, and wider bandwidth than an LTE / LTE-A carrier. Compared to LTE / LTE-A, an eCC may use different physical layer channel and signal structures, different waveforms, and different media access control (MAC) procedures. Specifically, data transmission on an eCC may span multiple time resources (transmission time intervals (TTIs) or subframes) and / or multiple frequency resources (channels). An eCC may use time division duplexing (TDD) and be deployed in a shared radio frequency spectrum band (e.g., where more than one operator may use the spectrum). In some cases, an eCC may be associated with a carrier aggregation (CA) configuration or a dual connectivity configuration (e.g., when multiple serving cells have suboptimal backhaul links).

[0055] In some aspects of the present disclosure, a base station may configure uplink resources for ULST from one or more UEs within an LBT frame. The base station may also configure a ULST window during which the UE may transmit a ULST, and during which the base station may monitor for ULST, if the UE is unable to transmit a ULST during the configured uplink resources of the LBT frame.

[0056] Figure 2 An example of a wireless communication system 200 that supports ULST technology using contention-based radio frequency spectrum according to aspects of the present disclosure is illustrated. The wireless communication system 200 may include a base station 105-a and a UE 115-a, which may be reference Figure 1 Examples of corresponding devices described.

[0057] In some examples of the wireless communication system 200, the base station 105-a and the UE 115-a can communicate using a communication link 220, which can provide both uplink and downlink communications. In some examples, the communication link 220 can use one or more component carriers to transmit waveforms between the base station 105-a and the UE 115-a, which waveforms may include, for example, orthogonal frequency division multiple access (OFDMA) waveforms, single carrier frequency division multiple access (SC-FDMA) waveforms, or resource block interleaved frequency division multiple access (FDMA) waveforms. The communication link 220 can be associated with a frequency in a shared radio frequency spectrum band. This example is given for illustrative purposes, and there may be other similar operating modes or deployment scenarios that provide LTE / LTE-A communications in a shared radio frequency spectrum band. In some examples, the base station 105-a can be deployed in a residential, small business, medium-sized business, or enterprise environment, and can allow the UE 115-a to establish a connection using the shared radio frequency spectrum band(s). Such a deployment may allow UE 115-a to operate using a shared radio frequency spectrum band and reduce data usage provided to UE 115-a via a licensed radio frequency spectrum band, which may help reduce costs for users of UE 115-a in some situations. In some examples, base station 105-a may include hardware for both licensed spectrum access and shared spectrum access.

[0058] As discussed above, when using shared RF spectrum, the base station 105-a and the UE 115-a can perform LBT procedures to determine that one or more resources (e.g., time resources, frequency resources, or a combination thereof) are available for transmission in the shared RF spectrum band. Also as discussed above, in some situations, it may be desirable to reduce the need for the base station to allocate uplink transmission resources, and to reduce the need for the UE 115-a to have to contend for access to carriers in the shared RF spectrum band. Various aspects of the present disclosure provide techniques for identifying a ULST in which a relatively small amount of data from the UE 115-a can be transmitted directly to the base station 105-a after the UE 115-a wins contention for a carrier in the shared RF spectrum band.

[0059] For example, if UE 115-a has an amount of data to be transmitted that is less than a threshold, all of the data can be transmitted in the ULST, thereby avoiding the need for base station 105-a to allocate separate uplink resources for the transmission, and also avoiding the need for UE 115-a to contend for access to the carrier of the shared radio frequency spectrum band at multiple times. In some examples, ULST can be used for SR, RACH request, short data packets with an amount of data less than a threshold, or a combination thereof. In some examples, an extended LBT procedure (e.g., CCA with a relatively large contention window) can be used before or after ULST to provide other wireless nodes with an enhanced likelihood of winning contention for the shared radio frequency spectrum band.

[0060] Figure 3 An example 300 of configured ULST uplink resources supporting ULST techniques using contention-based radio frequency spectrum, ULST periods, ULST windows, and LBT frames is illustrated in accordance with aspects of the present disclosure. In some cases, the example 300 may represent a configuration of a ULST uplink resource configured as described in reference to FIG. Figure 1 and 2 Aspects of the techniques performed by a UE 115 or base station 105 are described.

[0061] exist Figure 3 In the example 300, a number of ULST periods 305 may be allocated by one or more base stations (e.g., Figure 1-2 In some examples, the ULST period 305 can be associated with one or more SFNs and span the duration (T) of one or more corresponding 10ms radio frames. In some examples, the ULST window 310 can be configured as a portion of the ULST period 305 (e.g., the first 10ms duration of a 40ms ULST period), and the UE can contend for channel access and transmit a ULST during the ULST window 310. For example, the ULST window 310 can have a duration (W) configured by the base station. The base station can monitor for ULST during the configured ULST window 310. The first ULST window 310-a can be configured at Figure 3 In the example of FIG. 3 , the ULST window 310 begins at the beginning of the first ULST period 305-a after offset K 315 from SFN#0. The ratio of the periodicity defined by the duration (W) of the ULST window 310 and the duration (T) of the ULST period 305 can be the duty cycle (W / T) of the ULST window 310. In some examples, the ULST duty cycle parameter can be configured by the base station and can be selected to trade off between base station power consumption and potential uplink transmission delay. In some examples, the ULST duty cycle parameter can be configured via a system information block (SIB) periodically transmitted by the base station.

[0062] exist Figure 3In the example of , the base station can initiate transmissions associated with the LBT frame 320 during the first ULST period 305-a, and the LBT frame 320 can extend to the beginning of the second ULST period 305-b at SFN#K+T. In this example, the LBT frame 320 begins before the beginning of the second ULST window 310-b. In this example, certain downlink (D) subframes can include a downlink preamble and a physical frame format indicator channel (PFFICH) transmission 325. Figure 3 In the example of FIG, the first and third downlink subframes transmitted may include a downlink preamble and a PFFICH 325. In some examples, when data arrives at the UE, the UE may start a timer and monitor the downlink preamble and the PFFICH 325 for the duration of the timer. If the downlink preamble and the PFFICH 325 are detected, they may be used to determine subsequent uplink resources in the LBT frame 320 that may be used for ULST. If the downlink preamble and the PFFICH 325 are not detected, the UE may initiate an LBT procedure during one of the ULST windows 310. If the timer expires outside of the ULST window 310, the UE may periodically monitor downlink transmissions according to the configured monitoring parameters, and the UE may initiate an LBT procedure at the beginning of the next ULST window to transmit the ULST. Thus, the base station may monitor for ULST transmissions during the configured ULST uplink resources of the ULST window 310 and the LBT frame 320, and may refrain from monitoring at other times. In some examples, the configured ULST uplink resources of the LBT frame 320 can be physical uplink control channel (PUCCH) resources, which can be semi-statically assigned and located in the first uplink subframe of the LBT radio frame 320. In other examples, the ULST uplink resources of the LBT frame 320 can be dynamically assigned in the downlink preamble and PFFICH 325 transmission, or can be established uplink resources defined in the standard. In some examples, different UEs can be assigned to use different ULST uplink resources of the LBT frame 320, such as different frequency resources that can be allocated for ULST uplink resources within a time slot, which can reduce the possibility of ULST collisions from multiple UEs.

[0063] Figure 3Example 300 includes four different UE examples that may have data arriving for transmission at different times. In the first example, a first UE (UE1) may have data arriving at time 330 just before the start of an LBT frame 320. The first UE may initiate its timer to monitor for downlink preamble and PFFICH 325 transmissions, which the first UE may detect and use to determine uplink resources 335 for the first UE's ULST. In a second example, a second UE (UE2) may have data arriving at time 340 just after the last downlink preamble and PFFICH 325 transmission of the LBT frame 320. The second UE may initiate its UE2 timer 345 to monitor for downlink preamble and PFFICH 325 transmissions, which in this example are not detected, resulting in the expiration of the UE2 timer 345. In this example, the UE2 timer 345 expires during the ULST window 310-b, and thus the second UE can initiate an LBT procedure and, if the LBT procedure is successful, transmit the UE2 ULST 350. As indicated above, the duration of the UE2 timer 345 can be selected so that the UE2 ULST 350 does not collide with the LBT frame 320.

[0064] In a third example, a third UE (UE3) may have data arrive at time 355 just after the start of the LBT frame 320. The third UE may initiate its timer to monitor for downlink preamble and PFFICH 325 transmissions, which the third UE may detect and use to determine uplink resources for the third UE ULST 360. As mentioned above, in some examples, the first UE and the third UE may be configured to use different frequency resources for the ULST uplink resources, which may reduce the likelihood of collisions between the first UE ULST 335 and the third UE ULST 360. In a fourth example, a fourth UE (UE4) may have data arrive at time 365 during the LBT frame 320 but after the last downlink preamble and PFFICH 325 transmission of the LBT frame 320. The fourth UE may initiate its UE4 timer 370 to monitor for downlink preamble and PFFICH 325 transmissions, which in this example are not detected, resulting in the expiration of the UE4 timer 370. In this example, the UE4 timer 370 expires after the ULST window 310 - b closes, and thus the fourth UE may initiate an LBT procedure during the subsequent ULST window 310 - c and transmit the UE4 ULST 375 if the LBT procedure is successful.

[0065] Figure 4An example of a process flow 400 for using a ULST technique using contention-based radio frequency spectrum according to various aspects of the present disclosure is illustrated. The process flow 400 may include a base station 105-b, and a first UE 115-b and a second UE 115-c, which may be reference Figure 1 and 2 Examples of corresponding devices are described.

[0066] At block 405, the base station 105-b may configure a ULST period and window for UE ULST transmissions. At block 410, the base station 105-b may configure a UE timer for monitoring downlink transmissions after data arrival. The ULST period and window, and the UE timer may be as described above with reference to Figure 2 and 3 4. The base station 105-b may be configured as discussed above. The base station 105-b may transmit configuration information 415 to both the first UE 115-b and the second UE 115-c. Such configuration may be transmitted, for example, via control signaling (such as in a SIB or radio resource control (RRC) signaling). At box 420, data arrives at the first UE 115-b. At box 425, the first UE 115-b may initiate its UE timer and monitor downlink transmissions, which may include, for example, a downlink preamble, a PFFICH, or a combination thereof. Concurrently, during the time period of the UE timer of the first UE 115-b, the base station 105-b may initiate transmission / reception associated with an LBT frame, as indicated at box 430. The LBT frame transmission / reception 430 may include a downlink preamble and a PFFICH transmission, which may be detected at the first UE 115-b before expiration of the UE timer, and which may be used at the first UE 115-b, as indicated at box 435. The first UE 115 - b may thereby transmit the ULST 440 during the allocated uplink resources of the LBT frame transmission / reception 430 .

[0067] exist Figure 4 In the example of FIG4 , after the base station 105-b transmits the downlink preamble and PFFICH information, at block 445, data may arrive at the second UE 115-c. At block 450, the second UE 115-c may initiate a UE timer and monitor for downlink transmissions, which in this example are not detected, resulting in the expiration of the timer, as indicated at block 465. The second UE 115-c may then initiate an LBT procedure within the ULST window at block 470. At block 455, the base station 105-b may initiate a ULST window timer. At block 460, the base station 105-b may monitor for uplink transmissions during the ULST window. Following the LBT procedure at the second UE 115-c, a ULST 475 may be transmitted to the base station 105-b.

[0068] Figure 5 A block diagram of a wireless device 500 supporting ULST technology using contention-based radio frequency spectrum according to various aspects of the present disclosure is shown. The wireless device 500 may be a reference Figure 1 、 2 4. The wireless device 500 may include a receiver 505, a ULST manager 510, and a transmitter 515. The wireless device 500 may also include a processor. Each of these components may be in communication with each other.

[0069] The receiver 505 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 ULST technology using contention-based radio frequency spectrum, etc.). The information may be passed to other components of the device. The receiver 505 may be a reference Figure 8 Examples of various aspects of the transceiver 825 are described.

[0070] The ULST manager 510 may identify data to be transmitted to a base station; monitor one or more downlink transmissions from the base station; determine a scheduled uplink resource for an uplink transmission associated with the identified data based on detecting the one or more downlink transmissions from the base station; and initiate an LBT procedure for the uplink transmission associated with the identified data during a ULST window if one or more downlink transmissions from the base station are not detected within a specified time period. The ULST manager 510 may also be a reference to Figure 8 Examples of various aspects of the ULST manager 805 are described.

[0071] The transmitter 515 may transmit signals received from other components of the wireless device 500. In some examples, the transmitter 515 may be co-located with the receiver in a transceiver module. For example, the transmitter 515 may be a reference Figure 8 Examples of aspects of the described transceiver 825. The transmitter 515 may include a single antenna, or may include multiple antennas.

[0072] Figure 6 A block diagram of a wireless device 600 supporting ULST technology using contention-based radio frequency spectrum according to various aspects of the present disclosure is shown. The wireless device 600 may be a reference Figure 1 、 2 , 4, and 5. The wireless device 600 may include a receiver 605, a ULST manager 610, and a transmitter 635. The wireless device 600 may also include a processor. Each of these components may be in communication with each other.

[0073] The receiver 605 can receive information that can be passed to other components of the device. The receiver 605 can also perform reference Figure 5 The receiver 605 may be a device that is configured to perform the functions described in the preceding text. Figure 8 Examples of various aspects of the transceiver 825 are described.

[0074] ULST manager 610 may be a reference Figure 5 ULST manager 610 may include a data identification component 615, a downlink monitoring component 620, an uplink resource component 625, and an LBT component 630. ULST manager 610 may be a reference to Figure 8 Examples of various aspects of the ULST manager 805 are described.

[0075] The data identification component 615 can identify data to be transmitted to the base station. The downlink monitoring component 620 can monitor one or more downlink transmissions from the base station. In some cases, monitoring one or more downlink transmissions includes monitoring a downlink preamble associated with an LTB frame. In some cases, the scheduled uplink resources are determined based on the downlink preamble. In some cases, the scheduled uplink resources include resources of an uplink subframe associated with an LTB frame.

[0076] The uplink resource component 625 can determine the scheduled uplink resources for uplink transmission associated with the identified data based on detecting one or more downlink transmissions from the base station. In some cases, the scheduled uplink resources include one or more of semi-statically configured uplink resources of one or more uplink subframes of the LBT frame, predefined uplink resources of the first uplink subframe of the LBT frame, or dynamically configured resources identified in the downlink preamble. In some cases, the uplink transmission associated with the identified data includes an SR or random access request to schedule uplink resources for uplink transmission of the identified data. In some cases, the uplink transmission associated with the identified data includes a relatively short data packet containing user data.

[0077] The LBT component 630 can initiate an LBT procedure for the uplink transmission associated with the identified data during the ULST window if one or more downlink transmissions from the base station are not detected within a specified time period. In some cases, initiating the LBT procedure may include identifying resources within the ULST window for transmitting the uplink transmission associated with the identified data. In some cases, the resources within the ULST window for transmitting the uplink transmission associated with the identified data are semi-statically configured resources. In some cases, the resources within the ULST window for transmitting the uplink transmission associated with the identified data are received in the SIB from the base station. In some cases, the ULST window is outside the LBT frame.

[0078] The transmitter 635 may transmit signals received from other components of the wireless device 600. In some examples, the transmitter 635 may be co-located with the receiver in a transceiver module. For example, the transmitter 635 may be a reference Figure 8 Examples of aspects of the transceiver 825 are described. The transmitter 635 may utilize a single antenna, or may utilize multiple antennas.

[0079] Figure 7 A block diagram of a ULST manager 700 is shown, which may be an example of a corresponding component of the wireless device 500 or the wireless device 600. That is, the ULST manager 700 may be a reference to Figure 5 and 6 ULST manager 510 or ULST manager 610 are examples of aspects of the described ULST manager 510 or ULST manager 610. ULST manager 700 may also be a reference to Figure 8 Examples of various aspects of the ULST manager 805 are described.

[0080] ULST manager 700 may include an LBT component 705, an uplink resource component 710, a data size component 715, an uplink transmission generation component 720, a data identification component 725, a downlink monitoring component 730, and a timing component 735. Each of these modules may communicate with each other directly or indirectly (e.g., via one or more buses).

[0081] The LBT component 705 can initiate an LBT procedure for uplink transmissions associated with the identified data during the ULST window if one or more downlink transmissions from the base station are not detected within a specified time period. The uplink resource component 710 can determine a scheduled uplink resource for uplink transmissions associated with the identified data based on the detection of one or more downlink transmissions from the base station.

[0082] The data size component 715 can determine that the identified data is less than a size threshold. The uplink transmission generation component 720 can include the identified data in the uplink transmission associated with the identified data. The data identification component 725 can identify the data to be transmitted to the base station. The downlink monitoring component 730 can monitor one or more downlink transmissions from the base station.

[0083] The timing component 735 can initiate a timer upon identifying data to be transmitted to a base station; and terminate the timer in response to detecting one or more downlink transmissions from the base station. In some cases, the LBT procedure is initiated during the ULST window in response to the expiration of the timer.

[0084] Figure 8 A diagram of a system 800 including devices supporting ULST technology using contention-based radio frequency spectrum according to various aspects of the present disclosure is shown. For example, the system 800 may include a UE 115-d, which may be a reference Figure 1 、 2 Examples of wireless device 500, wireless device 600, or UE 115 described in and 4 to 7.

[0085] UE 115-d may also include a ULST manager 805, a memory 810, a processor 820, a transceiver 825, an antenna 830, and an eCC module 835. Each of these modules may communicate directly or indirectly with each other (e.g., via one or more buses). The ULST manager 805 may be as described with reference to FIG. Figure 5 –7 describes an example of a ULST manager.

[0086] The memory 810 may include random access memory (RAM) and read-only memory (ROM). The memory 810 may store computer-readable, computer-executable software including instructions that, when executed, cause the processor to perform the various functions described herein (e.g., using ULST technology based on contention-based radio spectrum, etc.). In some cases, the software 815 may not be directly executable by the processor, but instead causes the computer (e.g., when compiled and executed) to perform the functions described herein. The processor 820 may include an intelligent hardware device (e.g., a central processing unit (CPU), a microcontroller, an application-specific integrated circuit (ASIC), etc.).

[0087] The transceiver 825 can communicate bidirectionally with one or more networks via one or more antennas, wired or wireless links, as described above. For example, the transceiver 825 can communicate bidirectionally with the base station 105 or the UE 115. The transceiver 825 can also include a modem to modulate packets and provide the modulated packets to the antenna for transmission, and to demodulate packets received from the antenna. In some cases, the wireless device may include a single antenna 830. However, in some cases, the device may have more than one antenna 830, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

[0088] The eCC module 835 may enable operations using eCC, such as communications using shared or unlicensed spectrum, using reduced TTI or subframe durations, or using a large number of component carriers (CCs).

[0089] Figure 9 A block diagram of a wireless device 900 supporting ULST technology using contention-based radio frequency spectrum according to various aspects of the present disclosure is shown. The wireless device 900 may be a reference Figure 1 、 2 4. The wireless device 900 may include a receiver 905, a base station ULST manager 910, and a transmitter 915. The wireless device 900 may also include a processor. Each of these components may be in communication with each other.

[0090] The receiver 905 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 ULST technology using contention-based radio frequency spectrum, etc.). The information may be passed to other components of the device. The receiver 905 may be a reference Figure 12 Examples of aspects of the transceiver 1225 are described.

[0091] The base station ULST manager 910 may transmit one or more downlink transmissions associated with an LBT frame to at least one UE; configure a ULST window that does not overlap with the LBT frame; and monitor uplink transmissions from one or more UEs during the ULST window. Figure 12 Examples of various aspects of the base station ULST manager 1205 are described.

[0092] The transmitter 915 may transmit signals received from other components of the wireless device 900. In some examples, the transmitter 915 may be co-located with the receiver in a transceiver module. For example, the transmitter 915 may be a reference Figure 12 Examples of aspects of the described transceiver 1225. The transmitter 915 may include a single antenna, or may include multiple antennas.

[0093] Figure 10 A block diagram of a wireless device 1000 supporting ULST technology using contention-based radio frequency spectrum according to various aspects of the present disclosure is shown. The wireless device 1000 may be a reference Figure 1 、 2 , 4 and 9. The wireless device 1000 may include a receiver 1005, a base station ULST manager 1010 and a transmitter 1030. The wireless device 1000 may also include a processor. Each of these components may be in communication with each other.

[0094] The receiver 1005 can receive information that can be passed to other components of the device. The receiver 1005 can also perform a reference Figure 9 The receiver 1005 may be a device that performs the functions described in the embodiment of the present invention. Figure 12 Examples of various aspects of the transceiver 1225 are described.

[0095] The base station ULST manager 1010 may be a reference Figure 9 Examples of various aspects of the base station ULST manager 905 are described. The base station ULST manager 1010 may include a downlink transmission component 1015, a ULST window component 1020, and an uplink monitoring component 1025. The base station ULST manager 1010 may be referenced Figure 12 Examples of aspects of the base station ULST manager 1205 are described. A downlink transmission component 1015 can transmit one or more downlink transmissions associated with an LBT frame to at least one UE.

[0096] The ULST window component 1020 can configure a ULST window that does not overlap with the LBT frame. In some cases, configuring the ULST window includes configuring resources within the ULST window for uplink transmission. In some cases, the resources used for uplink transmission within the ULST window are semi-statically configured resources. In some cases, configuring the ULST window further includes transmitting a SIB indicating the ULST window and the resources configured for uplink transmission within the ULST window to one or more UEs.

[0097] The uplink monitoring component 1025 can monitor uplink transmissions from one or more UEs during the ULST window. In some cases, the uplink transmissions include one or more of an SR or random access request, a short data packet, or a combination thereof to schedule uplink resources for one or more subsequent uplink transmissions.

[0098] The transmitter 1030 may transmit signals received from other components of the wireless device 1000. In some examples, the transmitter 1030 may be co-located with the receiver in a transceiver module. For example, the transmitter 1030 may be a reference Figure 12 Examples of aspects of the described transceiver 1225. The transmitter 1030 may utilize a single antenna, or may utilize multiple antennas.

[0099] Figure 11 1 shows a block diagram of a base station ULST manager 1100, which may be an example of a corresponding component of the wireless device 900 or the wireless device 1000. That is, the base station ULST manager 1100 may be a reference to Figure 9 and 10 Examples of aspects of the base station ULST manager 910 or base station ULST manager 1010 are described. The base station ULST manager 1100 may also be referenced. Figure 12 Examples of various aspects of the base station ULST manager 1205 are described.

[0100] Base station ULST manager 1100 may include a ULST window component 1105, a data size component 1110, a UE timing component 1115, a downlink transmission component 1120, an uplink scheduling component 1125, and an uplink monitoring component 1130. Each of these modules may communicate with each other directly or indirectly (e.g., via one or more buses).

[0101] The ULST window component 1105 can configure a ULST window that does not overlap with the LBT frame. The data size component 1110 can configure a size threshold for transmitting user data in an uplink transmission during the ULST window. The UE timing component 1115 can configure the one or more UEs with a timer to monitor the one or more downlink transmissions; and configure the one or more UEs to initiate an uplink transmission during the ULST window if the one or more downlink transmissions are not detected before expiration of the timer.

[0102] The downlink transmission component 1120 can transmit one or more downlink transmissions associated with the LBT frame to at least one UE. The uplink scheduling component 1125 can schedule uplink resources in one or more uplink subframes of the LBT frame; and configure the one or more UEs to transmit uplink transmissions during the scheduled uplink resources when the one or more downlink transmissions are detected before the expiration of the timer. In some cases, the one or more downlink transmissions include a downlink preamble, and wherein the scheduled uplink resources are determined based on the downlink preamble. In some cases, the scheduled uplink resources include resources of an uplink subframe associated with the LBT frame. In some cases, the scheduled uplink resources include one or more of semi-statically configured uplink resources of one or more uplink subframes of the LBT frame, predefined uplink resources of the first uplink subframe of the LBT frame, or dynamically configured resources identified in the downlink preamble.

[0103] Uplink monitoring component 1130 can monitor uplink transmissions from one or more UEs during the ULST window. In some cases, the uplink transmissions include one or more of an SR or a random access request to schedule uplink resources for one or more subsequent uplink transmissions.

[0104] Figure 12 A diagram of a wireless system 1200 including devices supporting ULST technology using contention-based radio frequency spectrum according to various aspects of the present disclosure is shown. For example, the system 1200 may include a base station 105-d, which may be a reference Figure 1 、 2 , 4, and 9 through 11. The base station 105-d may also include components for two-way voice and data communication, including components for transmitting communications and components for receiving communications. For example, the base station 105-d may communicate bidirectionally with one or more UEs 115.

[0105] The base station 105-d may also include a base station ULST manager 1205, a memory 1210, a processor 1220, a transceiver 1225, an antenna 1230, a base station communication module 1235, and a network communication module 1230. Each of these modules may communicate with each other directly or indirectly (e.g., via one or more buses). The base station ULST manager 1205 may be a reference Figure 9 –11 describes an example of a base station ULST manager.

[0106] Memory 1210 may include RAM and ROM. Memory 1210 may store computer-readable, computer-executable software including instructions that, when executed, cause the processor to perform the various functions described herein (e.g., using ULST technology based on contention-based radio frequency spectrum, etc.). In some cases, software 1215 may not be directly executable by the processor, but may (e.g., when compiled and executed) cause the computer to perform the functions described herein. Processor 1220 may include an intelligent hardware device (e.g., a CPU, a microcontroller, an ASIC, etc.).

[0107] The transceiver 1225 can communicate bidirectionally with one or more networks via one or more antennas, wired or wireless links, as described above. For example, the transceiver 1225 can communicate bidirectionally with the base station 105 or the UE 115. The transceiver 1225 can also include a modem to modulate packets and provide the modulated packets to the antenna for transmission, and to demodulate packets received from the antenna. In some cases, the wireless device may include a single antenna 1230. However, in some cases, the device may have more than one antenna 1230, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

[0108] The base station communication module 1235 can manage communications with other base stations 105 and can include a controller or scheduler for controlling communications with the UE 115 in coordination with the other base stations 105. For example, the base station communication module 1235 can coordinate the scheduling of transmissions to the UE 115 for various interference mitigation techniques, such as beamforming or joint transmission. In some examples, the base station communication module 1235 can provide an X2 interface within an LTE / LTE-A wireless communication network technology to provide communications between base stations 105.

[0109] The network communication module 1230 may manage communications with the core network (eg, via one or more wired backhaul links). For example, the network communication module 1230 may manage the delivery of data communications for client devices, such as one or more UEs 115.

[0110] Figure 13 A flow chart illustrating a method 1300 for using ULST technology based on contention-based radio frequency spectrum according to various aspects of the present disclosure is shown. The operations of the method 1300 may be performed as described with reference to Figure 1 、 24 and 5 (such as UE 115 or its components) are implemented. For example, the operations of method 1300 may be performed by a ULST manager as described herein. In some examples, UE 115 may execute a set of codes for controlling functional elements of the device to perform the functions described below. Additionally or alternatively, UE 115 may use dedicated hardware to perform various aspects of the functions described below.

[0111] At block 1305, UE 115 may identify data to be transmitted to a base station, as described above with reference to Figure 2 In some examples, the operation of block 1305 may be performed as described in reference to Figure 6 and 7 The data described identifies the component to execute.

[0112] At block 1310, UE 115 may monitor one or more downlink transmissions from the base station, as described above with reference to Figure 2 In some examples, the operations of block 1310 may be performed as described in reference to Figure 6 and 7 The downlink monitoring component described is performed.

[0113] At block 1315, UE 115 may determine scheduled uplink resources for uplink transmission associated with the identified data based on detecting one or more downlink transmissions from the base station, as described above with reference to Figure 2 In some examples, the operation of block 1315 may be performed as described in reference to Figure 6 and 7 The uplink resource component described is performed.

[0114] At block 1320, the UE 115 may initiate an LBT procedure for uplink transmissions associated with the identified data during the ULST window if one or more downlink transmissions from the base station are not detected within a specified time period, as described above with reference to Figure 2 In some examples, the operation of block 1320 may be performed as described in reference to Figure 6 and 7 The LBT components described are implemented.

[0115] Figure 14 1 is a flow chart illustrating a method 1400 for using ULST technology based on contention-based radio frequency spectrum according to various aspects of the present disclosure. The operations of the method 1400 may be performed as described with reference to FIG. Figure 1 、 24 and 5 (such as UE 115 or its components) are implemented. For example, the operations of method 1400 can be performed by a ULST manager as described herein. In some examples, UE 115 can execute a set of codes for controlling functional elements of the device to perform the functions described below. Additionally or alternatively, UE 115 can use dedicated hardware to perform various aspects of the functions described below.

[0116] At block 1405, UE 115 may identify data to be transmitted to a base station, as described above with reference to Figure 2 In some examples, the operation of block 1405 may be performed as described in reference to Figure 6 and 7 The data described identifies the component to execute.

[0117] At block 1410, the UE 115 may initiate a timer upon identifying data to be transmitted to the base station, as described above with reference to Figure 2 In some examples, the operations of block 1410 may be performed as described in reference to Figure 6 and 7 Describes the timing components to execute.

[0118] At block 1415, UE 115 may monitor one or more downlink transmissions from the base station, as described above with reference to Figure 2 In some examples, the operation of block 1415 may be performed as described in reference to Figure 6 and 7 The downlink monitoring component described is performed.

[0119] At block 1420, the UE 115 may determine scheduled uplink resources for uplink transmission associated with the identified data based on detecting one or more downlink transmissions from the base station, as described above with reference to Figure 2 In some examples, the operations of block 1420 may be performed as described in reference to Figure 6 and 7 The uplink resource component described is performed.

[0120] At block 1425, UE 115 may terminate the timer in response to detecting one or more downlink transmissions from the base station, as described above with reference to Figure 2 In some examples, the operation of block 1425 may be performed as described in reference to Figure 6 and 7 Describes the timing components to execute.

[0121] At block 1430, the UE 115 may initiate an LBT procedure for uplink transmissions associated with the identified data during the ULST window if one or more downlink transmissions from the base station are not detected within a specified time period, as described above with reference to Figure 2 In some examples, the operations of block 1430 may be performed as described in reference to Figure 6 and 7 The LBT components described are implemented.

[0122] Figure 15 1 is a flow chart illustrating a method 1500 for using ULST technology based on contention-based radio frequency spectrum according to various aspects of the present disclosure. The operations of the method 1500 may be performed as described with reference to FIG. Figure 1 、 2 4 and 5 (such as UE 115 or its components) are implemented. For example, the operations of method 1500 can be performed by a ULST manager as described herein. In some examples, UE 115 can execute a set of codes for controlling functional elements of the device to perform the functions described below. Additionally or alternatively, UE 115 can use dedicated hardware to perform various aspects of the functions described below.

[0123] At block 1505, UE 115 may identify data to be transmitted to a base station, as described above with reference to Figure 2 In some examples, the operation of block 1505 may be performed as described in reference to Figure 6 and 7 The data described identifies the component to execute.

[0124] At block 1510, the UE 115 may determine that the identified data is less than a size threshold, as described above with reference to Figure 2 In some examples, the operations of block 1510 may be performed as described in reference to Figure 6 and 7 Describes the data size components to perform.

[0125] At block 1515, UE 115 may monitor one or more downlink transmissions from the base station, as described above with reference to Figure 2-4 In some examples, the operation of block 1515 may be performed as described with reference to Figure 6 and 7 The downlink monitoring component described is performed.

[0126] At block 1520, UE 115 may determine scheduled uplink resources for uplink transmission associated with the identified data based on detecting one or more downlink transmissions from the base station, as described above with reference to Figure 2-4 In some examples, the operations of block 1520 may be performed as described with reference to Figure 6 and 7 The uplink resource component described is performed.

[0127] At block 1525, the UE 115 may initiate an LBT procedure for uplink transmissions associated with the identified data during the ULST window if one or more downlink transmissions from the base station are not detected within a specified time period, as described above with reference to Figure 2-4 In some examples, the operation of block 1525 may be performed as described with reference to Figure 6 and 7 The LBT components described are implemented.

[0128] At block 1530, the UE 115 may include the identified data in an uplink transmission associated with the identified data, as described above with reference to Figure 2 In some examples, the operation of block 1530 may be performed as described in reference to Figure 6 and 7 The described uplink transmission generation component is performed.

[0129] Figure 16 A flow chart illustrating a method 1600 for using ULST technology based on contention-based radio frequency spectrum according to various aspects of the present disclosure is shown. The operations of the method 1600 may be performed as described with reference to Figure 1 、 2 4 and 5 (such as base station 105 or its components) are implemented. For example, the operations of method 1600 may be performed by a base station ULST manager as described herein. In some examples, base station 105 may execute a set of codes for controlling functional elements of the device to perform the functions described below. Additionally or alternatively, base station 105 may use dedicated hardware to perform various aspects of the functions described below.

[0130] At block 1605, the base station 105 may transmit one or more downlink transmissions associated with the LBT frame to at least one UE, as described above with reference to Figure 2 In some examples, the operation of block 1605 may be performed as described in reference to Figure 10 and 11 The downlink transmission components described are performed.

[0131] At block 1610, the base station 105 may configure a ULST window that does not overlap with the LBT frame, as described above with reference to Figure 2 In some examples, the operations of block 1610 may be performed as described in reference to Figure 10 and 11 Describes the implementation of the ULST window component.

[0132] At block 1615, the base station 105 may monitor uplink transmissions from one or more UEs during the ULST window, as described above with reference to Figure 2 In some examples, the operation of block 1615 may be performed as described in reference to Figure 10 and 11 The uplink monitoring component described is performed.

[0133] Figure 17 A flow chart illustrating a method 1700 for using ULST technology based on contention-based radio frequency spectrum according to various aspects of the present disclosure is shown. The operations of the method 1700 may be performed as described with reference to Figure 1 、 2 4 and 5 (such as base station 105 or its components) are implemented. For example, the operations of method 1700 may be performed by a base station ULST manager as described herein. In some examples, base station 105 may execute a set of codes for controlling functional elements of the device to perform the functions described below. Additionally or alternatively, base station 105 may use dedicated hardware to perform various aspects of the functions described below.

[0134] At block 1705, the base station 105 may transmit one or more downlink transmissions associated with the LBT frame to at least one UE, as described above with reference to Figure 2 In some examples, the operation of block 1705 may be performed as described in reference to Figure 10 and 11 The downlink transmission components described are performed.

[0135] At block 1710, the base station 105 may configure a ULST window that does not overlap with the LBT frame, as described above with reference to Figure 2 In some examples, the operations of block 1710 may be performed as described in reference to Figure 10 and 11 Describes the implementation of the ULST window component.

[0136] At block 1715, the base station 105 may configure a size threshold for transmitting user data in uplink transmissions during the ULST window, as described above with reference to Figure 2 In some examples, the operation of block 1715 may be performed as described in reference to Figure 10 and 11 Describes the data size components to perform.

[0137] At block 1720, the base station 105 may monitor uplink transmissions from one or more UEs during the ULST window, as described above with reference to Figure 2 In some examples, the operations of block 1720 may be performed as described in reference to Figure 10 and 11The uplink monitoring component described is performed.

[0138] It should be noted that these methods describe possible implementations, and that the operations and steps may be rearranged or otherwise modified to make other implementations possible. In some examples, aspects from two or more methods may be combined. For example, aspects of each method may include steps or aspects of the other methods, or other steps or techniques described herein. Thus, aspects of the present disclosure may provide ULST techniques using contention-based radio frequency spectrum.

[0139] The description herein is provided to enable those skilled in the art to make or use the present disclosure. Various modifications to the present disclosure will be apparent to those skilled in the art, and the universal principles defined herein may be applied to other variations without departing from the scope of the present disclosure. Thus, the present disclosure is not limited to the examples and designs described herein, but should be accorded the broadest scope consistent with the principles and novel features disclosed herein.

[0140] The functions described herein can be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, each function can be stored on or transmitted by a computer-readable medium as one or more instructions or codes. Other examples and implementations fall within the scope and spirit of this disclosure and the appended claims. For example, due to the nature of software, the functions described above can be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination thereof. Features that implement the functions can also be physically located in various locations, including being distributed so that parts of the functions are implemented at different physical locations. As used herein (including in the claims), the term "and / or" used in a listing of two or more items means that any of the listed items can be used alone, or any combination of two or more listed items can be used. For example, if a composition is described as comprising components A, B, and / or C, the composition can include only A; only B; only C; a combination of A and B; a combination of A and C; a combination of B and C; or a combination of A, B, and C. Similarly, as used herein (including in the claims), “or” used in a list of items (e.g., in a list of items followed by a phrase such as “at least one of” or “one or more of”) indicates a disjunctive list so that, for example, a list “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).

[0141] Computer-readable media include both non-transient computer storage media and communication media, and include any media that facilitates a computer program to be transferred from one place to another. Non-transient storage media can be any available medium that can be accessed by a general or special-purpose computer. As an example and not limitation, non-transient computer-readable media may include RAM, ROM, electrically erasable programmable read-only memory (EEPROM), compact disc (CD) ROM or other optical disc storage, disk storage or other magnetic storage devices, or any other non-transient medium that can be used to carry or store the desired program code means of an instruction or data structure form and can be accessed by a general or special-purpose computer or a general or special-purpose processor. Any connection is also properly referred to as a computer-readable medium. For example, if software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwaves, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwaves are included in the definition of medium. Disk and disc, as used herein, include CDs, laser discs, optical discs, digital versatile discs (DVDs), floppy disks, and Blu-ray discs, where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

[0142] The technology described herein can be used in various wireless communication systems, such as code division multiple access (CDMA), time division multiple access (TDMA), FDMA, OFDMA, SC-FDMA and other systems. The terms "system" and "network" are often used interchangeably. A CDMA system can implement radio technologies such as CDMA2000 and Universal Terrestrial Radio Access (UTRA). CDMA2000 covers IS2000, IS-95 and IS-856 standards. IS-2000 versions 0 and A are often referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is often referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other CDMA variants. A TDMA system can implement radio technologies such as Global System for Mobile Communications (GSM). OFDMA systems can implement radio technologies such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), IEEE 802.11, IEEE 802.16 (WiMAX), IEEE 802.20, and Flash-OFDM. UTRA and E-UTRA are parts of the Universal Mobile Telecommunications System (UMTS). 3GPP LTE and LTE-A are new versions of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization called the "3rd Generation Partnership Project" (3GPP). CDMA2000 and UMB are described in documents from an organization called the "3rd Generation Partnership Project 2" (3GPP2). The techniques described herein can be used for the systems and radio technologies mentioned above as well as for other systems and radio technologies. However, the description herein describes an LTE system for example purposes, and LTE terminology is used in much of the description above, but these techniques can also be applied to applications other than LTE.

[0143] In LTE / LTE-A networks (including the networks described herein), the term evolved Node B (eNB) may be used generally to describe a base station. One or more wireless communication systems described herein may include heterogeneous LTE / LTE-A networks in which different types of eNBs provide coverage for various geographic regions. For example, each eNB or base station may provide communication coverage for a macro cell, a small cell, or other types of cells. Depending on the context, the term "cell" is a 3GPP term that may be used to describe a base station, a carrier or CC associated with a base station, or a coverage area (e.g., a sector, etc.) of a carrier or base station.

[0144] A base station may include or may be referred to by those skilled in the art as a base transceiver station, a radio base station, an access point (AP), a radio transceiver, a B node, an evolved B node (eNB), a home B node, a home evolved B node, or some other suitable term. The geographic coverage area of ​​a base station may be divided into sectors that constitute only a portion of the coverage area. One or more wireless communication systems described herein may include different types of base stations (e.g., macro or small cell base stations). The UE described herein may be able to communicate with various types of base stations and network equipment (including macro eNBs, small cell eNBs, relay base stations, etc.). There may be overlapping geographic coverage areas of different technologies. In some cases, different coverage areas may be associated with different communication technologies. In some cases, the coverage area of ​​one communication technology may overlap with the coverage area associated with another technology. Different technologies may be associated with the same base station or different base stations.

[0145] A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with a service subscription with a network provider. In contrast to a macro cell, a small cell is a low-power base station that may operate in the same or different frequency band (e.g., licensed, unlicensed, etc.) as the macro cell. According to various examples, small cells may include pico cells, femto cells, and micro cells. A pico cell, for example, may cover a smaller geographic area and may allow unrestricted access by UEs with a service subscription with a network provider. A femto cell may also cover a smaller geographic area (e.g., a residence) and may provide restricted access by UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs of users in the residence, etc.). An eNB for a macro cell may be referred to as a macro eNB. An eNB for a small cell may be referred to as a small cell eNB, pico eNB, femto eNB, or home eNB. An eNB may support one or more (e.g., two, three, four, etc.) cells (e.g., CCs). A UE may be able to communicate with various types of base stations and network equipment, including macro eNBs, small cell eNBs, relay base stations, etc.

[0146] One or more wireless communication systems described herein may support synchronous or asynchronous operation. For synchronous operation, each base station may have similar frame timing, and transmissions from different base stations may be approximately aligned in time. For asynchronous operation, each base station may have different frame timing, and transmissions from different base stations may not be aligned in time. The techniques described herein may be used for either synchronous or asynchronous operation.

[0147] Downlink transmissions described herein may also be referred to as forward link transmissions, and uplink transmissions may also be referred to as reverse link transmissions. Each communication link described herein (including, for example, Figure 1 and 2 The wireless communication systems 100 and 200 of the present invention may include one or more carriers, wherein each carrier may be a signal composed of multiple subcarriers (e.g., waveform signals of different frequencies). Each modulated signal may be sent on a different subcarrier and may carry control information (e.g., reference signals, control channels, etc.), overhead information, user data, etc. The communication links described herein (e.g., Figure 1 The communication link 125 may use frequency division duplex (FDD) (e.g., using paired spectrum resources) or TDD operation (e.g., using unpaired spectrum resources) to transmit bidirectional communications. A frame structure for FDD (e.g., frame structure type 1) and a frame structure for TDD (e.g., frame structure type 2) may be defined.

[0148] Thus, aspects of the present disclosure can provide ULST technology using contention-based radio frequency spectrum. It should be noted that these methods describe possible implementations, and the operations and steps can be rearranged or otherwise modified to make other implementations possible. In some examples, aspects from two or more methods can be combined.

[0149] The various illustrative blocks and modules described in conjunction with the disclosure herein may be implemented or executed using a general-purpose processor, digital signal processor (DSP), ASIC, 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 herein. A general-purpose processor may be a microprocessor, but in an alternative embodiment, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration). Thus, the functions described herein may be performed by one or more other processing units (or cores) on at least one integrated circuit (IC). In various examples, other types of ICs (e.g., structured / platform ASICs, FPGAs, or other semi-custom ICs) may be used, which may be programmed in any manner known in the art. The functions of each unit may also be implemented, in whole or in part, using instructions implemented in a memory formatted to be executed by one or more general-purpose or special-purpose processors.

Claims

1. A method of wireless communication, comprising: identifying data to be transmitted to the base station; initiating a timer upon identifying the data to be transmitted to the base station; monitoring one or more downlink transmissions from the base station, the one or more downlink transmissions indicating scheduled uplink resources allocated for an uplink short transmission (ULST) within a listen-before-talk (LBT) frame; determining scheduled uplink resources for uplink transmission associated with the identified data based at least in part on detecting the one or more downlink transmissions from the base station prior to expiration of the timer; as well as Upon detecting the one or more downlink transmissions from the base station before expiration of the timer, performing a ULST associated with the identified data using the scheduled uplink resources within the LBT frame.

2. The method of claim 1, further comprising: The timer is terminated in response to detecting the one or more downlink transmissions from the base station.

3. The method according to claim 1, wherein Monitoring the one or more downlink transmissions comprises: A downlink preamble associated with the LBT frame is monitored.

4. The method according to claim 3, wherein: The scheduled uplink resources are determined based at least in part on the downlink preamble.

5. The method according to claim 3, wherein: The scheduled uplink resources include resources of an uplink subframe associated with the LBT frame.

6. The method according to claim 5, wherein: The scheduled uplink resources include one or more of semi-statically configured uplink resources of one or more uplink subframes of the LBT frame, predefined uplink resources of the first uplink subframe of the LBT frame, or dynamically configured resources identified in the downlink preamble.

7. The method of claim 1, further comprising: In case the one or more downlink transmissions from the base station are not detected before expiration of the timer, a listen-before-talk (LBT) procedure is initiated for the uplink transmission associated with the identified data during an uplink short transmission (ULST) window.

8. The method of claim 7, wherein: Initiating the LBT procedure further includes: Resources within the ULST window for transmitting the uplink transmission associated with the identified data are identified.

9. The method of claim 8, wherein: The identified resources within the ULST window used to transmit the uplink transmission associated with the identified data are semi-statically configured resources.

10. The method of claim 8, wherein: The identified resources within the ULST window for transmitting the uplink transmission associated with the identified data are received in a system information block (SIB) from the base station.

11. The method according to claim 7, wherein: The ULST window is outside the LBT frame.

12. The method of claim 1, wherein: The uplink transmission associated with the identified data comprises a scheduling request SR or a random access request to schedule uplink resources for uplink transmission of the identified data.

13. The method of claim 1, further comprising: determining that the identified data is less than a size threshold; as well as The identified data is included in the uplink transmission associated with the identified data.

14. A method of wireless communication, comprising: transmitting one or more downlink transmissions associated with a listen-before-talk (LBT) frame to one or more user equipment (UE), the one or more downlink transmissions indicating scheduled uplink resources allocated for an uplink short transmission (ULST) within the LBT frame; configuring the one or more UEs with a timer for monitoring the one or more downlink transmissions; configuring the one or more UEs to perform ULST using the scheduled uplink resources within the LBT frame upon detecting the one or more downlink transmissions before expiration of the timer; as well as Uplink transmissions within the ULST from one or more UEs are monitored on the scheduled uplink resources within the LBT frame.

15. The method of claim 14, further comprising: Schedule uplink resources in one or more uplink subframes of the LBT frame.

16. The method of claim 14, wherein: The one or more downlink transmissions include a downlink preamble, and wherein the scheduled uplink resources are determined based at least in part on the downlink preamble.

17. The method of claim 14, wherein: The scheduled uplink resources include resources of an uplink subframe associated with the LBT frame.

18. The method of claim 17, wherein: The scheduled uplink resources include one or more of semi-statically configured uplink resources of one or more uplink subframes of the LBT frame, predefined uplink resources of the first uplink subframe of the LBT frame, or dynamically configured resources identified in a downlink preamble.

19. The method of claim 14, further comprising: Configure uplink short transmission ULST window; The one or more UEs are configured to initiate an LBT procedure for uplink transmission within the ULST window if the one or more downlink transmissions are not detected before expiration of the timer.

20. The method of claim 19, further comprising: Resources within the ULST window are configured for uplink transmission.

21. The method of claim 20, wherein: The resources configured for uplink transmission within the ULST window are semi-statically configured resources.

22. The method of claim 20, further comprising: A system information block (SIB) indicating the resources configured for uplink transmission within the ULST window is transmitted to the one or more UEs.

23. The method of claim 14, wherein: The uplink transmission includes one or more of a scheduling request SR or a random access request to schedule uplink resources for one or more subsequent uplink transmissions.

24. The method of claim 19, further comprising: A size threshold for transmitting user data in an uplink transmission within the ULST window is configured.

25. A device for wireless communication, comprising: means for identifying data to be transmitted to the base station; means for initiating a timer upon identifying said data to be transmitted to said base station; means for monitoring one or more downlink transmissions from the base station, the one or more downlink transmissions indicating scheduled uplink resources allocated for uplink short transmissions (ULST) within a listen-before-talk (LBT) frame; means for determining scheduled uplink resources for uplink transmission associated with the identified data based at least in part on detecting the one or more downlink transmissions from the base station prior to expiration of the timer; as well as Means for performing a ULST associated with the identified data using the scheduled uplink resources within the LBT frame upon detecting the one or more downlink transmissions from the base station prior to expiration of the timer.

26. The apparatus of claim 25, further comprising: means for terminating the timer in response to detecting the one or more downlink transmissions from the base station.

27. The apparatus of claim 25, wherein: The means for monitoring the one or more downlink transmissions comprises: Means for monitoring a downlink preamble associated with the LBT frame.

28. The apparatus of claim 27, wherein: The scheduled uplink resources are determined based at least in part on the downlink preamble.

29. The apparatus of claim 27, wherein: The scheduled uplink resources include resources of an uplink subframe associated with the LBT frame.

30. The apparatus of claim 29, wherein: The scheduled uplink resources include one or more of semi-statically configured uplink resources of one or more uplink subframes of the LBT frame, predefined uplink resources of the first uplink subframe of the LBT frame, or dynamically configured resources identified in the downlink preamble.

31. The apparatus of claim 25, further comprising: Means for initiating a listen-before-talk (LBT) procedure for the uplink transmission associated with the identified data during an uplink short transmission (ULST) window if the one or more downlink transmissions from the base station are not detected before expiration of the timer.

32. The apparatus of claim 31, wherein: The means for initiating the LBT procedure further comprises: Means for identifying resources within the LBT frame for transmitting an uplink transmission associated with the identified data.

33. The apparatus of claim 32, wherein: The identified resources within the ULST window used to transmit the uplink transmission associated with the identified data are semi-statically configured resources.

34. The apparatus of claim 32, wherein: The identified resources within the ULST window for transmitting the uplink transmission associated with the identified data are received in a system information block (SIB) from the base station.

35. The apparatus of claim 31 , wherein: The ULST window is outside the LBT frame.

36. The apparatus of claim 25, wherein: The uplink transmission associated with the identified data comprises a scheduling request SR or a random access request to schedule uplink resources for uplink transmission of the identified data.

37. The apparatus of claim 25, further comprising: means for determining that the identified data is less than a size threshold; as well as Means for including the identified data in the uplink transmission associated with the identified data.

38. A device for wireless communication, comprising: means for transmitting one or more downlink transmissions associated with a listen-before-talk (LBT) frame to one or more user equipment (UE), the one or more downlink transmissions indicating scheduled uplink resources allocated for an uplink short transmission (ULST) within the LBT frame; means for configuring the one or more UEs with a timer for monitoring the one or more downlink transmissions; means for configuring the one or more UEs to perform ULST using the scheduled uplink resources within the LBT frame upon detecting the one or more downlink transmissions prior to expiration of the timer; as well as Means for monitoring uplink transmissions within the ULST from one or more UEs on the scheduled uplink resources within the LBT frame.

39. The apparatus of claim 38, further comprising: Means for scheduling uplink resources in one or more uplink subframes of the LBT frame.

40. The apparatus of claim 38, wherein The one or more downlink transmissions include a downlink preamble, and wherein the scheduled uplink resources are determined based at least in part on the downlink preamble.

41. The apparatus of claim 38, wherein: The scheduled uplink resources include resources of an uplink subframe associated with the LBT frame.

42. The apparatus of claim 41, wherein The scheduled uplink resources include one or more of semi-statically configured uplink resources of one or more uplink subframes of the LBT frame, predefined uplink resources of the first uplink subframe of the LBT frame, or dynamically configured resources identified in a downlink preamble.

43. The apparatus of claim 38, further comprising: means for configuring an uplink short transmission ULST window; Means for configuring the one or more UEs to initiate an LBT procedure for uplink transmission within the ULST window if the one or more downlink transmissions are not detected before expiration of the timer.

44. The apparatus of claim 43, further comprising: means for configuring resources within the ULST window for uplink transmission.

45. The apparatus of claim 44, wherein: The resources configured for uplink transmission within the ULST window are semi-statically configured resources.

46. ​​The apparatus of claim 44, further comprising: means for transmitting a system information block (SIB) indicating the resources configured for uplink transmission within the ULST window to the one or more UEs.

47. The apparatus of claim 38, wherein: The uplink transmission includes one or more of a scheduling request SR or a random access request to schedule uplink resources for one or more subsequent uplink transmissions.

48. The apparatus of claim 43, further comprising: Means for configuring a size threshold for transmitting user data in an uplink transmission within the ULST window.

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