Uplink short transmission techniques using contention-based radio frequency spectrum

Uplink short transmissions (ULSTs) may be configured in a wireless communications 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) may transmit a ULST and during which the base station may monitor for ULSTs. A UE having 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 to have the base station allocate separate uplink resources outside of the configured uplink resources or the ULST window.

BACKGROUND

The following relates generally to wireless communication, and more specifically to uplink short transmission (ULST) techniques using a contention-based radio frequency spectrum.

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

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

SUMMARY

The present disclosure, for example, relates to wireless communication systems, and more particularly to uplink short transmission (ULST) techniques using a contention-based radio frequency spectrum. As previously indicated, in some cases it may be desirable to reduce the need for a base station to allocate uplink transmission resources, as well as to reduce the need for a 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 ULSTs in which relatively small amounts of data from a UE may be transmitted to a base station directly following the UE winning contention to a carrier in the shared radio frequency spectrum band.

In some aspects of the disclosure, a base station may configure uplink resources within a listen-before-talk (LBT) frame for ULSTs from one or more UEs. A UE having 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 to have the base station allocate separate uplink resources for the transmission. The base station also may configure a ULST window during which a UE may transmit a ULST and during which the base station may monitor for ULSTs. In some examples, the ULST window may be configured such that ULSTs are not transmitted by a UE during an LBT frame. In some cases, the base station may configure a UE with a timer, and the UE may start the timer and monitor for downlink transmissions in response to data arriving at the UE for uplink transmission until the timer expires. In some cases, a downlink transmission may include a downlink preamble that may be used to determine uplink resources for transmission of the ULST within an associated LBT frame. In other cases, a UE may not detect a downlink preamble prior to expiry of the timer, in which case a UE may initiate an LBT procedure for the ULST during a configured ULST window.

A method of wireless communication is described. The method may include identifying data to be transmitted to a base station, monitoring for one or more downlink transmissions from the base station, determining, based at least in part on detecting one or more downlink transmissions from the base station, scheduled uplink resources for an uplink transmission associated with the identified data, and initiating an LBT procedure for the uplink transmission associated with the identified data during a ULST window in an absence of detecting one or more downlink transmissions from the base station within a specified time period.

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 for one or more downlink transmissions from the base station, means for determining, based at least in part on detecting one or more downlink transmissions from the base station, scheduled uplink resources for an uplink transmission associated with the identified data, and means for initiating an LBT procedure for the uplink transmission associated with the identified data during a ULST window in an absence of detecting one or more downlink transmissions from the base station within a specified time period.

A further apparatus is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be operable to cause the processor to identify data to be transmitted to a base station, monitor for one or more downlink transmissions from the base station, determine, based at least in part on detecting one or more downlink transmissions from the base station, scheduled uplink resources for an uplink transmission associated with the identified data, and initiate an LBT procedure for the uplink transmission associated with the identified data during a ULST window in an absence of detecting one or more downlink transmissions from the base station within a specified time period.

A non-transitory computer readable medium for wireless communication is described. The non-transitory computer-readable medium may include instructions to cause a processor to identify data to be transmitted to a base station, monitor for one or more downlink transmissions from the base station, determine, based on detecting one or more downlink transmissions from the base station, scheduled uplink resources for an uplink transmission associated with the identified data and initiate an LBT procedure for the uplink transmission associated with the identified data during a ULST window in an absence of detecting one or more downlink transmissions from the base station within a specified time period.

Some examples of the method, apparatus, or non-transitory computer-readable medium described above may further include processes, features, means, or instructions for initiating a timer upon identifying the data to be transmitted to the base station. Some examples of the method, apparatus, or non-transitory computer-readable medium described above may further include processes, features, means, or instructions for 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 an expiration of the timer.

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

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

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

In some examples of the method, apparatus, or non-transitory computer-readable medium described above, the 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. In some examples of the method, apparatus, or non-transitory computer-readable medium described above, the ULST window is outside of an LBT frame.

In some examples of the method, apparatus, or non-transitory computer-readable medium described above, 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.

Some examples of the method, apparatus, or non-transitory computer-readable medium described above may further include processes, features, means, or instructions for determining that the identified data is less than a size threshold. Some examples of the method, apparatus, or non-transitory computer-readable medium described above may further include processes, features, means, or instructions for including the identified data in the uplink transmission associated with the identified data.

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 a ULST window that is non-overlapping with the LBT frame and monitoring for uplink transmissions from one or more UEs during the ULST window.

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 a ULST window that is non-overlapping with the LBT frame and means for monitoring for uplink transmissions from one or more UEs during the ULST window.

A further apparatus is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be operable to cause the processor to transmit one or more downlink transmissions associated with an LBT frame to at least one UE, configure a ULST window that is non-overlapping with the LBT frame and monitor for uplink transmissions from one or more UEs during the ULST window.

A non-transitory computer readable medium for wireless communication is described. The non-transitory computer-readable medium may include instructions to cause a processor to transmit one or more downlink transmissions associated with an LBT frame to at least one UE, configure a ULST window that is non-overlapping with the LBT frame and monitor for uplink transmissions from one or more UEs during the ULST window.

Some examples of the method, apparatus, or non-transitory computer-readable medium described above may further include processes, features, means, or instructions for configuring the one or more UEs with a timer for monitoring for the one or more downlink transmissions. Some examples of the method, apparatus, or non-transitory computer-readable medium described above may further include processes, features, means, or instructions for configuring the one or more UEs to initiate the uplink transmissions during the ULST window in an absence of detecting the one or more downlink transmissions prior to expiration of the timer.

Some examples of the method, apparatus, or non-transitory computer-readable medium described above may further include processes, features, means, or instructions for scheduling uplink resources in one or more uplink subframes of the LBT frame. Some examples of the method, apparatus, or non-transitory computer-readable medium described above may further include processes, features, means, or instructions for configuring the one or more UEs to transmit the uplink transmissions during the scheduled uplink resources upon detecting the one or more downlink transmissions prior to expiration of the timer.

In some examples of the method, apparatus, or non-transitory computer-readable medium described above, the one or more downlink transmissions comprise a downlink preamble, and where the scheduled uplink resources are determined based on the downlink preamble. In some examples of the method, apparatus, or non-transitory computer-readable medium described above, the scheduled uplink resources comprise resources of an uplink subframe associated with the LBT frame.

In some examples of the method, apparatus, or non-transitory computer-readable medium described above, the scheduled uplink resources comprise one or more of semi-statically configured uplink resources of one or more uplink subframes of the LBT frame, predefined uplink resources of a first uplink subframe of the LBT frame, or dynamically configured resources identified in a downlink preamble.

In some examples of the method, apparatus, or non-transitory computer-readable medium described above, configuring the ULST window comprises: configuring resources within the ULST window for uplink transmissions. In some examples of the method, apparatus, or non-transitory computer-readable medium described above, the resources within the ULST window for uplink transmissions are semi-statically configured resources.

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

Some examples of the method, apparatus, or non-transitory computer-readable medium described above may further include processes, features, means, or instructions for configuring a size threshold for transmitting user data in uplink transmissions during the ULST window.

DETAILED DESCRIPTION

Techniques are described in which a shared radio frequency spectrum band may be used for communications over a wireless communication system. In some examples, the shared radio frequency spectrum band may be used for Long Term Evolution (LTE)/LTE-Advanced (LTE-A) communications and may be shared with devices that operate according to different radio access technologies (RATs), such as Wi-Fi devices that operate according to Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards, for example. The shared radio frequency spectrum band may be used in combination with, or independent from, a licensed radio frequency spectrum band. The licensed radio frequency spectrum band may include a radio frequency spectrum band for which transmitting apparatuses may not contend for access (e.g., a radio frequency spectrum band licensed to particular users for particular uses, such as a licensed radio frequency spectrum band usable for LTE/LTE-A communications). The shared radio frequency spectrum band may include a radio frequency spectrum band for which transmitting apparatuses may contend for access using listen-before-talk (LBT) procedures (e.g., a radio frequency spectrum band that is available for unlicensed use, such as Wi-Fi use, a radio frequency spectrum band that is available for use by different RATs, or a radio frequency spectrum band that is available for use by multiple operators in an equally shared or prioritized manner).

In some aspects of the disclosure, a base station may configure uplink resources within an LBT frame for uplink short transmissions (ULSTs) from one or more user equipment (UEs). The base station also may configure an ULST window during which a UE may transmit a ULST and during which the base station may monitor for ULSTs in the event that the UE is not able to transmit the ULST during the configured uplink resources of the LBT frame.

In some examples, ULSTs may be used to transmit relatively small amounts of data from the UE. A UE having 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 to have the base station allocate separate uplink resources for the transmission, and may also avoid the need for the UE to contend for access to a carrier of the shared radio frequency spectrum band on multiple occasions to transmit the data. In some examples, ULSTs may be used for scheduling requests (SRs), random access channel (RACH) requests, short data packets having an amount of data that is less than the threshold value, or combinations thereof. In some examples, an extended LBT procedure (e.g., a clear channel assessment (CCA) having a relatively large contention window) may be used prior to or after the ULST to provide other wireless nodes with enhanced likelihood of winning contention for the shared radio frequency spectrum band.

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

In some examples, UEs may be configured such that a ULST window in which the UE may contend for access and transmit a ULST is non-overlapping with an LBT frame. In some cases, the base station may configure a 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 for downlink transmissions until the timer expires. In some cases, a downlink transmission may include a downlink preamble that may be used to determine uplink resources for transmission of the ULST within an associated LBT frame. In other cases, a UE may not detect a downlink preamble prior to expiry of the timer, in which case a UE may initiate an LBT procedure for the ULST during a configured ULST window. The duration of the timer may be selected to provide that the UE will not contend for access to the shared radio frequency spectrum band or transmit a ULST until after completion of an LBT frame in the event that the ULST window starts during an LBT frame.

In some examples, certain uplink resources of an LBT frame may be configured with uplink resources that are available for ULSTs of one or more UEs. The uplink resources within the LBT frame may include, for example, configured resources of a 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 may 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 a UE may be selected to provide that, if the UE does not detect a downlink preamble, the timer will expire after the last subframe of the LBT frame, and thus the UE is less likely to initiate a transmission that may interfere with the LBT frame.

Aspects of the disclosure are initially described in the context of a wireless communication system that uses a shared radio frequency spectrum band and LBT procedures for accessing the shared radio frequency spectrum band. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to ULST techniques for wireless transmissions using the shared radio frequency spectrum band.

FIG. 1illustrates an example of a wireless communications system100in accordance with various aspects of the present disclosure. The wireless communications system100includes base stations105, UEs115, and a core network130. In some examples, the wireless communications system100may be an LTE/LTE-A network. In some examples, the base stations105may configure UEs115for ULSTs, and UEs115may identify ULST data and transmit ULSTs in allocated uplink resources within an LBT frame or after performing an LBT procedure during a ULST window that is outside of an LBT frame.

Base stations105may wirelessly communicate with UEs115via one or more base station antennas. Each base station105may provide communication coverage for a respective geographic coverage area110. Communication links125shown in wireless communications system100may include uplink transmissions from a UE115to a base station105, or downlink transmissions, from a base station105to a UE115. UEs115may be dispersed throughout the wireless communications system100, and each UE115may be stationary or mobile. A UE115may also be referred to as a mobile station, a subscriber station, a remote unit, a wireless device, an access terminal (AT), a handset, a user agent, a client, or like terminology. A UE115may also be a cellular phone, a wireless modem, a handheld device, a personal computer, a tablet, a personal electronic device, a machine type communication (MTC) device, etc.

In some cases, a UE115or base station105may operate in a shared or unlicensed frequency spectrum. These devices may perform an LBT procedure, such as a CCA, prior to communicating in order to determine whether the channel is available. A 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 a received signal strength indication (RSSI) of a power meter indicates that a channel is occupied. Specifically, signal power that is concentrated in a certain bandwidth and exceeds a predetermined noise floor may indicate another wireless transmitter. A CCA may also include detection of specific sequences that indicate use of the channel. For example, another device may transmit a specific preamble prior to transmitting a data sequence.

In some cases, wireless communications system100may utilize one or more enhanced component carriers (eCCs). An eCC may be a non-backward compatible carrier characterized by shorter symbol duration, larger subcarrier spacing, and wider bandwidth than the LTE/LTE-A carriers. An eCC may use different physical layer channel and signal structures, different waveforms, and different medium access control (MAC) procedures compared to LTE/LTE-A. In particular, data transmission on 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 a suboptimal backhaul link).

In some aspects of the disclosure, a base station may configure uplink resources within an LBT frame for ULSTs from one or more UEs. The base station also may configure a ULST window during which a UE may transmit a ULST and during which the base station may monitor for ULSTs in the event that the UE is not able to transmit the ULST during the configured uplink resources of the LBT frame.

FIG. 2illustrates an example of a wireless communications system200that supports ULST techniques using a contention-based radio frequency spectrum in accordance with aspects of the present disclosure. Wireless communications system200may include base station105-aand UE115-a, which may be examples of the corresponding devices described with reference toFIG. 1.

In some examples of the wireless communication system200, base station105-aand UE115-amay communicate using communications link220, which may provide for both uplink and downlink communications. The communications link220, in some examples, may transmit waveforms between base station105-aand the UE115-ausing one or more component carriers that may include 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, for example. The communications link220may be associated with a frequency in the shared radio frequency spectrum band. This example is presented for illustrative purposes and there may be other similar modes of operation or deployment scenarios that provide LTE/LTE-A communication in a shared radio frequency spectrum band. In some examples, base station105-amay be deployed in a residential, small business, medium business, or enterprise environment, and may allow UE115-ato establish connections using shared radio frequency spectrum band(s). Such a deployment may allow UE115-ato operate using shared radio frequency spectrum bands and reduce data usage provided to UE115-athrough licensed radio frequency spectrum bands, which may help reduce costs for a user of UE115-ain some cases. In some examples, base station105-amay include hardware for both licensed spectrum access as well as shared spectrum access.

As discussed above, when using a shared radio frequency spectrum, base station105-aand UE115-amay perform LBT procedures to determine that the one or more resources (e.g., time resources, frequency resources, or combinations thereof) are available for transmission in the shared radio frequency spectrum band. As also discussed above, in some cases it may be desirable to reduce the need for a base station to allocate uplink transmission resources, as well as to reduce the need for UE115-ato have to contend for access to a carrier in the shared radio frequency spectrum band. Various aspects of the present disclosure provide techniques for identifying ULSTs in which relatively small amounts of data from UE115-amay be transmitted to base station105-adirectly following UE115-awinning contention to a carrier in the shared radio frequency spectrum band.

For example, if UE115-ahas an amount of data to be transmitted that is less than a threshold value, all of the data may be transmitted in the ULST, thus avoiding the need to have base station105-aallocate separate uplink resources for the transmission, and may also avoid the need for UE115-ato contend for access to a carrier of the shared radio frequency spectrum band on multiple occasions. In some examples, ULSTs may be used for SRs, RACH requests, short data packets having an amount of data that is less than the threshold value, or combinations thereof. In some examples, an extended LBT procedure (e.g., a CCA having a relatively large contention window) may be used prior to or after the ULST to provide other wireless nodes with enhanced likelihood of winning contention for the shared radio frequency spectrum band.

FIG. 3illustrates an example300of ULST periods, ULST windows and configured ULST uplink resources of LBT frames that support ULST techniques using a contention-based radio frequency spectrum in accordance with aspects of the present disclosure. In some cases, the example300may represent aspects of techniques performed by a UE115or base station105as described with reference toFIGS. 1 and 2.

In the example300ofFIG. 3, a number of ULST periods305may be configured by one or more base stations (e.g., base stations105ofFIGS. 1-2). The ULST periods305may, in some examples, be associated with one or more SFNs and span a duration (T) of one or more corresponding 10 ms radio frames. In some examples, a ULST window310may be configured as a portion of the ULST period305(e.g., a first 10 ms duration of a 40 ms ULST period) and a UE may contend for channel access and transmit a ULST during a ULST window310. A ULST window310may have a duration (W) that is configured by a base station, for example. A base station may monitor for ULSTs during the configured ULST windows310. First ULST window310-amay begin at the start of first ULST period305-a, in the example ofFIG. 3, following an offset K315from SFN#0. A ratio of the duration (W) of the ULST window310to the periodicity as defined by the duration (T) of the ULST period305may be the duty cycle (W/T) of the ULST window310. In some examples, ULST duty cycle parameters may be configured by a base station, and may be selected to trade-off between base station power consumption and potential uplink transmission delays. The ULST duty cycle parameters may be configured, in some examples, via a system information block (SIB) that is periodically transmitted by a base station.

In the example ofFIG. 3, a base station may initiate transmissions associated with an LBT frame320during first ULST period305-a, and LBT frame320may extend into the beginning of second ULST period305-bat SFN #K+T. In this example, LBT frame320starts prior to the start of second ULST window310-b. In this example, certain downlink (D) subframes may include a downlink preamble and physical frame format indicator channel (PFFICH) transmission325. In the example ofFIG. 3, the first and third transmitted downlink subframes may include the downlink preamble and PFFICH325. In some examples, when data arrives at a UE, the UE may initiate a timer and monitor for downlink preamble and PFFICH325for the duration of the timer. If a downlink preamble and PFFICH325is detected, it may be used to determine subsequent uplink resources of the LBT frame320that may be used for the ULST. If a downlink preamble and PFFICH325is not detected, the UE may initiate an LBT procedure during one of the ULST windows310. If the timer expires outside of a ULST window310, the UE may periodically monitor for downlink transmissions according to configured monitoring parameters, and the UE may initiate an LBT procedure to transmit the ULST at the start of a next ULST window. Therefore, a base station may monitor for ULST transmissions during ULST windows310and the configured ULST uplink resources of the LBT frame320, and may suppress monitoring at other times. In some examples, the configured ULST uplink resources of the LBT frame320may be physical uplink control channel (PUCCH) resources that may be semi-statically assigned, and located in a first uplink subframe of LBT radio frame320. In other examples, the ULST uplink resources of the LBT frame320may be dynamically assigned in the downlink preamble and PFFICH325transmission, or may be established uplink resources defined in a standard. In some examples, different UEs may be assigned to use different ULST uplink resources of the LBT frame320, such as different frequency resources within a time slot that may be allocated for ULST uplink resources, which may reduce the likelihood of a collision of ULSTs from multiple UEs.

The example300ofFIG. 3includes four different examples of UEs which may have data arrive for transmission at different times. In a first example, a first UE (UE1) may have a data arrival at time330just before the start of LBT frame320. The first UE may initiate its timer to monitor for the downlink preamble and PFFICH325transmission, which the first UE may detect and use to determine uplink resources335for a ULST for the first UE. In a second example, a second UE (UE2) may have a data arrival at time340just after the last downlink preamble and PFFICH325transmission of LBT frame320. The second UE may initiate its UE2 timer345to monitor for the downlink preamble and PFFICH325transmission, which is not detected in this example, leading to the UE2 timer345expiring. In this example, UE2 timer345expired during ULST window310-b, and thus the second UE may initiate an LBT procedure and transmit UE2 ULST350if the LBT procedure is successful. As indicated above, the duration of UE2 timer345may be selected such that UE2 ULST350does not collide with LBT frame320.

In a third example, a third UE (UE3) may have a data arrival at time355just after the start of LBT frame320. The third UE may initiate its timer to monitor for the downlink preamble and PFFICH325transmission, which the third UE may detect and use to determine uplink resources for a third UE ULST360. As mentioned above, in some examples the first UE and the third UE may be configured to use different frequency resources of the ULST uplink resources which may reduce the likelihood of a collision of the first UE ULST335and the third UE ULST360. In a fourth example, a fourth UE (UE4) may have a data arrival at time365during LBT frame320but after the last downlink preamble and PFFICH325transmission of LBT frame320. The fourth UE may initiate its UE4 timer370to monitor for the downlink preamble and PFFICH325transmission, which is not detected in this example, leading to the UE4 timer370expiring. In this example, UE4 timer370expires after ULST window310-bcloses, and thus the fourth UE may initiate an LBT procedure and transmit UE4 ULST375during subsequent ULST window310-cif the LBT procedure is successful.

FIG. 4illustrates an example of a process flow400for ULST techniques using a contention-based radio frequency spectrum in accordance with various aspects of the present disclosure. Process flow400may include base station105-b, and first UE115-band second UE115-c, which may be examples of the corresponding devices described with reference toFIGS. 1 and 2.

At block405, base station105-bmay configure ULST periods and windows for UE ULST transmissions. At block410, base station105-bmay configure a UE timer for monitoring for downlink transmissions after data arrival. The ULST periods and windows, and the UE timer, may be configured as discussed above with respect toFIGS. 2 and 3. Base station105-bmay transmit configuration information415to both first UE115-band second UE115-c. Such configuration may be transmitted via control signaling, such as in an SIB or in radio resource control (RRC) signaling, for example. At block420, data arrives at first UE115-b. At block425, first UE115-bmay initiate its UE timer and monitor for downlink transmissions that may include, for example, a downlink preamble, PFFICH, or combinations thereof. Meanwhile during the time period of the UE timer of first UE115-b, base station105-bmay initiate transmissions/receptions associated with an LBT frame, as indicated at block430. The LBT frame transmissions/receptions430may include downlink preamble and PFFICH transmissions, which may be detected at first UE115-bprior to the expiration of the UE timer, and which may be used at first UE115-b, as indicated at block435. First UE115-bmay thus transmit ULST440during allocated uplink resources of LBT frame transmission/reception430.

In the example ofFIG. 4, data may arrive at second UE115-cat block445, after base station105-btransmitted downlink preamble and PFFICH information. At block450, second UE115-cmay initiate a UE timer and monitor for downlink transmissions which are not detected in this example, leading to timer expiration as indicated at block465. Second UE115-cmay then, at block470, initiate an LBT procedure in a ULST window. Base station105-b, at block455, may initiate a ULST window timer. At block460, base station105-bmay monitor for uplink transmissions during the ULST window. Following the LBT procedure at second UE115-c, a ULST475may be transmitted to base station105-b.

FIG. 5shows a block diagram of a wireless device500that supports ULST techniques using a contention-based radio frequency spectrum in accordance with various aspects of the present disclosure. Wireless device500may be an example of aspects of a UE115described with reference toFIGS. 1, 2, and 4. Wireless device500may include receiver505, ULST manager510, and transmitter515. Wireless device500may also include a processor. Each of these components may be in communication with each other.

The receiver505may 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 techniques using the contention-based radio frequency spectrum, etc.). Information may be passed on to other components of the device. The receiver505may be an example of aspects of the transceiver825described with reference toFIG. 8.

The ULST manager510may identify data to be transmitted to a base station, monitor for one or more downlink transmissions from the base station, determine, based on detecting one or more downlink transmissions from the base station, schedule uplink resources for an uplink transmission associated with the identified data, and initiate an LBT procedure for the uplink transmission associated with the identified data during a ULST window in an absence of detecting one or more downlink transmissions from the base station within a specified time period. The ULST manager510may also be an example of aspects of the ULST manager805described with reference toFIG. 8.

The transmitter515may transmit signals received from other components of wireless device500. In some examples, the transmitter515may be collocated with a receiver in a transceiver module. For example, the transmitter515may be an example of aspects of the transceiver825described with reference toFIG. 8. The transmitter515may include a single antenna, or may include a plurality of antennas.

FIG. 6shows a block diagram of a wireless device600that supports ULST techniques using a contention-based radio frequency spectrum in accordance with various aspects of the present disclosure. Wireless device600may be an example of aspects of a wireless device500or a UE115described with reference toFIGS. 1, 2, 4, and 5. Wireless device600may include receiver605, ULST manager610and transmitter635. Wireless device600may also include a processor. Each of these components may be in communication with each other.

The receiver605may receive information which may be passed on to other components of the device. The receiver605may also perform the functions described with reference to the receiver505ofFIG. 5. The receiver605may be an example of aspects of the transceiver825described with reference toFIG. 8.

The ULST manager610may be an example of aspects of ULST manager505described with reference toFIG. 5. The ULST manager610may include data identifying component615, downlink monitoring component620, uplink resource component625and LBT component630. The ULST manager610may be an example of aspects of the ULST manager805described with reference toFIG. 8.

The data identifying component615may identify data to be transmitted to a base station. The downlink monitoring component620may monitor for one or more downlink transmissions from the base station. In some cases, the monitoring for one or more downlink transmissions comprises: monitoring for a downlink preamble associated with an LBT frame. In some cases, the scheduled uplink resources are determined based on the downlink preamble. In some cases, the scheduled uplink resources comprise resources of an uplink subframe associated with the LBT frame.

The uplink resource component625may determine, based on detecting one or more downlink transmissions from the base station, scheduled uplink resources for an uplink transmission associated with the identified data. In some cases, the scheduled uplink resources comprise one or more of semi-statically configured uplink resources of one or more uplink subframes of the LBT frame, predefined uplink resources of a 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 comprises an SR or a 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 comprises relatively short data packets containing user data.

The LBT component630may initiate an LBT procedure for the uplink transmission associated with the identified data during a ULST window in an absence of detecting one or more downlink transmissions from the base station 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 a SIB from the base station. In some cases, the ULST window is outside of an LBT frame.

The transmitter635may transmit signals received from other components of wireless device600. In some examples, the transmitter635may be collocated with a receiver in a transceiver module. For example, the transmitter635may be an example of aspects of the transceiver825described with reference toFIG. 8. The transmitter635may utilize a single antenna, or may utilize a plurality of antennas.

FIG. 7shows a block diagram of a ULST manager700which may be an example of the corresponding component of wireless device500or wireless device600. That is, ULST manager700may be an example of aspects of ULST manager510or ULST manager610described with reference toFIGS. 5 and 6. The ULST manager700may also be an example of aspects of the ULST manager805described with reference toFIG. 8.

The ULST manager700may include LBT component705, uplink resource component710, data size component715, uplink transmission generating component720, data identifying component725, downlink monitoring component730and timing component735. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses).

The LBT component705may initiate an LBT procedure for the uplink transmission associated with the identified data during a ULST window in an absence of detecting one or more downlink transmissions from the base station within a specified time period. The uplink resource component710may determine, based on detecting one or more downlink transmissions from the base station, scheduled uplink resources for an uplink transmission associated with the identified data.

The data size component715may determine that the identified data is less than a size threshold. The uplink transmission generating component720may include the identified data in the uplink transmission associated with the identified data. The data identifying component725may identify data to be transmitted to a base station. The downlink monitoring component730may monitor for one or more downlink transmissions from the base station.

The timing component735may initiate a timer upon identifying the data to be transmitted to the base station, and terminate the timer in response to detecting one or more downlink transmissions from the base station. In some cases, an LBT procedure is initiated during the ULST window in response to an expiration of the timer.

FIG. 8shows a diagram of a system800including a device that supports ULST techniques using a contention-based radio frequency spectrum in accordance with various aspects of the present disclosure. For example, system800may include UE115-d, which may be an example of a wireless device500, a wireless device600, or a UE115as described with reference toFIGS. 1, 2, and 4 through 7.

UE115-dmay also include ULST manager805, memory810, processor820, transceiver825, antenna830and eCC module835. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses). The ULST manager805may be an example of a ULST manager as described with reference toFIGS. 5-7.

The memory810may include random access memory (RAM) and read only memory (ROM). The memory810may store computer-readable, computer-executable software including instructions that, when executed, cause the processor to perform various functions described herein (e.g., ULST techniques using the contention-based radio frequency spectrum, etc.). In some cases, the software815may not be directly executable by the processor but may cause a computer (e.g., when compiled and executed) to perform functions described herein. The processor820may include an intelligent hardware device, (e.g., a central processing unit (CPU), a microcontroller, an application specific integrated circuit (ASIC), etc.)

The transceiver825may communicate bi-directionally, via one or more antennas, wired, or wireless links, with one or more networks, as described above. For example, the transceiver825may communicate bi-directionally with a base station105or a UE115. The transceiver825may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas. In some cases, the wireless device may include a single antenna830. However, in some cases the device may have more than one antenna830, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The eCC module835may enable operations using eCCs such as communication using shared or unlicensed spectrum, using reduced TTIs or subframe durations, or using a large number of component carriers (CCs).

FIG. 9shows a block diagram of a wireless device900that supports ULST techniques using a contention-based radio frequency spectrum in accordance with various aspects of the present disclosure. Wireless device900may be an example of aspects of a base station105described with reference toFIGS. 1, 2, and 4. Wireless device900may include receiver905, base station ULST manager910and transmitter915. Wireless device900may also include a processor. Each of these components may be in communication with each other.

The receiver905may 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 techniques using the contention-based radio frequency spectrum, etc.). Information may be passed on to other components of the device. The receiver905may be an example of aspects of the transceiver1225described with reference toFIG. 12.

The base station ULST manager910may transmit one or more downlink transmissions associated with an LBT frame to at least one UE, configure a ULST window that is non-overlapping with the LBT frame, and monitor for uplink transmissions from one or more UEs during the ULST window. The base station ULST manager910may also be an example of aspects of the base station ULST manager1205described with reference toFIG. 12.

The transmitter915may transmit signals received from other components of wireless device900. In some examples, the transmitter915may be collocated with a receiver in a transceiver module. For example, the transmitter915may be an example of aspects of the transceiver1225described with reference toFIG. 12. The transmitter915may include a single antenna, or may include a plurality of antennas.

FIG. 10shows a block diagram of a wireless device1000that supports ULST techniques using a contention-based radio frequency spectrum in accordance with various aspects of the present disclosure. Wireless device1000may be an example of aspects of a wireless device900or a base station105described with reference toFIGS. 1, 2, 4, and 9. Wireless device1000may include receiver1005, base station ULST manager1010and transmitter1030. Wireless device1000may also include a processor. Each of these components may be in communication with each other.

The receiver1005may receive information which may be passed on to other components of the device. The receiver1005may also perform the functions described with reference to the receiver905ofFIG. 9. The receiver1005may be an example of aspects of the transceiver1225described with reference toFIG. 12.

The base station ULST manager1010may be an example of aspects of base station ULST manager905described with reference toFIG. 9. The base station ULST manager1010may include downlink transmission component1015, ULST window component1020and uplink monitoring component1025. The base station ULST manager1010may be an example of aspects of the base station ULST manager1205described with reference toFIG. 12. The downlink transmission component1015may transmit one or more downlink transmissions associated with an LBT frame to at least one UE.

The ULST window component1020may configure a ULST window that is non-overlapping with the LBT frame. In some cases, configuring the ULST window comprises: configuring resources within the ULST window for uplink transmissions. In some cases, the resources within the ULST window for uplink transmissions are semi-statically configured resources. In some cases, configuring the ULST window further comprises: transmitting an SIB to the one or more UEs with the ULST window and the resources within the ULST window configured for uplink transmissions.

The uplink monitoring component1025may monitor for uplink transmissions from one or more UEs during the ULST window. In some cases, the uplink transmissions comprise one or more of an SR, a random access request to schedule uplink resources for one or more subsequent uplink transmissions, a short data packet, or combinations thereof.

The transmitter1030may transmit signals received from other components of wireless device1000. In some examples, the transmitter1030may be collocated with a receiver in a transceiver module. For example, the transmitter1030may be an example of aspects of the transceiver1225described with reference toFIG. 12. The transmitter1030may utilize a single antenna, or may utilize a plurality of antennas.

FIG. 11shows a block diagram of a base station ULST manager1100which may be an example of the corresponding component of wireless device900or wireless device1000. That is, base station ULST manager1100may be an example of aspects of base station ULST manager910or base station ULST manager1010described with reference toFIGS. 9 and 10. The base station ULST manager1100may also be an example of aspects of the base station ULST manager1205described with reference toFIG. 12.

The base station ULST manager1100may include ULST window component1105, data size component1110, UE timing component1115, downlink transmission component1120, uplink scheduling component1125and uplink monitoring component1130. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses).

The ULST window component1105may configure a ULST window that is non-overlapping with the LBT frame. The data size component1110may configure a size threshold for transmitting user data in uplink transmissions during the ULST window. The UE timing component1115may configure the one or more UEs with a timer for monitoring for the one or more downlink transmissions, and configure the one or more UEs to initiate the uplink transmissions during the ULST window in an absence of detecting the one or more downlink transmissions prior to expiration of the timer.

The downlink transmission component1120may transmit one or more downlink transmissions associated with an LBT frame to at least one UE. The uplink scheduling component1125may schedule uplink resources in one or more uplink subframes of the LBT frame, and configure the one or more UEs to transmit the uplink transmissions during the scheduled uplink resources upon detecting the one or more downlink transmissions prior to expiration of the timer. In some cases, the one or more downlink transmissions comprise a downlink preamble, and where the scheduled uplink resources are determined based on the downlink preamble. In some cases, the scheduled uplink resources comprise resources of an uplink subframe associated with the LBT frame. In some cases, the scheduled uplink resources comprise one or more of semi-statically configured uplink resources of one or more uplink subframes of the LBT frame, predefined uplink resources of a first uplink subframe of the LBT frame, or dynamically configured resources identified in a downlink preamble.

The uplink monitoring component1130may monitor for uplink transmissions from one or more UEs during the ULST window. In some cases, the uplink transmissions comprise one or more of an SR or a random access request to schedule uplink resources for one or more subsequent uplink transmissions.

FIG. 12shows a diagram of a wireless system1200including a device that supports ULST techniques using a contention-based radio frequency spectrum in accordance with various aspects of the present disclosure. For example, system1200may include base station105-d, which may be an example of a wireless device900, a wireless device1000, or a base station105as described with reference toFIGS. 1, 2, 4, and 9 through 11. Base station105-dmay also include components for bi-directional voice and data communications including components for transmitting communications and components for receiving communications. For example, base station105-dmay communicate bi-directionally with one or more UEs115.

Base station105-dmay also include base station ULST manager1205, memory1210, processor1220, transceiver1225, antenna1230, base station communications module1235and network communications module1240. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses). The base station ULST manager1205may be an example of a base station ULST manager as described with reference toFIGS. 9-11.

The memory1210may include RAM and ROM. The memory1210may store computer-readable, computer-executable software including instructions that, when executed, cause the processor to perform various functions described herein (e.g., ULST techniques using the contention-based radio frequency spectrum, etc.). In some cases, the software1215may not be directly executable by the processor but may cause a computer (e.g., when compiled and executed) to perform functions described herein. The processor1220may include an intelligent hardware device, (e.g., a CPU, a microcontroller, an ASIC, etc.)

The transceiver1225may communicate bi-directionally, via one or more antennas, wired, or wireless links, with one or more networks, as described above. For example, the transceiver1225may communicate bi-directionally with a base station105or a UE115. The transceiver1225may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas. In some cases, the wireless device may include a single antenna1230. However, in some cases the device may have more than one antenna1230, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The network communications module1240may manage communications with the core network (e.g., via one or more wired backhaul links). For example, the network communications module1240may manage the transfer of data communications for client devices, such as one or more UEs115.

FIG. 13shows a flowchart illustrating a method1300for ULST techniques using a contention-based radio frequency spectrum in accordance with various aspects of the present disclosure. The operations of method1300may be implemented by a device such as a UE115or its components as described with reference toFIGS. 1, 2 and 4. For example, the operations of method1300may be performed by the ULST manager as described herein. In some examples, the UE115may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the UE115may perform aspects of the functions described below using special-purpose hardware.

At block1305, the UE115may identify data to be transmitted to a base station as described above with reference toFIGS. 2-4. In certain examples, the operations of block1305may be performed by the data identifying component as described with reference toFIGS. 6 and 7.

At block1310, the UE115may monitor for one or more downlink transmissions from the base station as described above with reference toFIGS. 2-4. In certain examples, the operations of block1310may be performed by the downlink monitoring component as described with reference toFIGS. 6 and 7.

At block1315, the UE115may determine, based on detecting one or more downlink transmissions from the base station, scheduled uplink resources for an uplink transmission associated with the identified data as described above with reference toFIGS. 2-4. In certain examples, the operations of block1315may be performed by the uplink resource component as described with reference toFIGS. 6 and 7.

At block1320, the UE115may initiate an LBT procedure for the uplink transmission associated with the identified data during a ULST window in an absence of detecting one or more downlink transmissions from the base station within a specified time period as described above with reference toFIGS. 2-4. In certain examples, the operations of block1320may be performed by the LBT component as described with reference toFIGS. 6 and 7.

FIG. 14shows a flowchart illustrating a method1400for ULST techniques using a contention-based radio frequency spectrum in accordance with various aspects of the present disclosure. The operations of method1400may be implemented by a device such as a UE115or its components as described with reference toFIGS. 1, 2, and 4. For example, the operations of method1400may be performed by the ULST manager as described herein. In some examples, the UE115may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the UE115may perform aspects of the functions described below using special-purpose hardware.

At block1405, the UE115may identify data to be transmitted to a base station as described above with reference toFIGS. 2-4. In certain examples, the operations of block1405may be performed by the data identifying component as described with reference toFIGS. 6 and 7.

At block1410, the UE115may initiate a timer upon identifying the data to be transmitted to the base station as described above with reference toFIGS. 2-4. In certain examples, the operations of block1410may be performed by the timing component as described with reference toFIGS. 6 and 7.

At block1415, the UE115may monitor for one or more downlink transmissions from the base station as described above with reference toFIGS. 2-4. In certain examples, the operations of block1415may be performed by the downlink monitoring component as described with reference toFIGS. 6 and 7.

At block1420, the UE115may determine, based on detecting one or more downlink transmissions from the base station, scheduled uplink resources for an uplink transmission associated with the identified data as described above with reference toFIGS. 2-4. In certain examples, the operations of block1420may be performed by the uplink resource component as described with reference toFIGS. 6 and 7.

At block1425, the UE115may terminate the timer in response to detecting one or more downlink transmissions from the base station as described above with reference toFIGS. 2-4. In certain examples, the operations of block1425may be performed by the timing component as described with reference toFIGS. 6 and 7.

At block1430, the UE115may initiate an LBT procedure for the uplink transmission associated with the identified data during a ULST window in an absence of detecting one or more downlink transmissions from the base station within a specified time period as described above with reference toFIGS. 2-4. In certain examples, the operations of block1430may be performed by the LBT component as described with reference toFIGS. 6 and 7.

FIG. 15shows a flowchart illustrating a method1500for ULST techniques using a contention-based radio frequency spectrum in accordance with various aspects of the present disclosure. The operations of method1500may be implemented by a device such as a UE115or its components as described with reference toFIGS. 1, 2, and 4. For example, the operations of method1500may be performed by the ULST manager as described herein. In some examples, the UE115may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the UE115may perform aspects of the functions described below using special-purpose hardware.

At block1505, the UE115may identify data to be transmitted to a base station as described above with reference toFIGS. 2-4. In certain examples, the operations of block1505may be performed by the data identifying component as described with reference toFIGS. 6 and 7.

At block1510, the UE115may determine that the identified data is less than a size threshold as described above with reference toFIGS. 2-4. In certain examples, the operations of block1510may be performed by the data size component as described with reference toFIGS. 6 and 7.

At block1515, the UE115may monitor for one or more downlink transmissions from the base station as described above with reference toFIGS. 2-4. In certain examples, the operations of block1515may be performed by the downlink monitoring component as described with reference toFIGS. 6 and 7.

At block1520, the UE115may determine, based on detecting one or more downlink transmissions from the base station, scheduled uplink resources for an uplink transmission associated with the identified data as described above with reference toFIGS. 2-4. In certain examples, the operations of block1520may be performed by the uplink resource component as described with reference toFIGS. 6 and 7.

At block1525, the UE115may initiate an LBT procedure for the uplink transmission associated with the identified data during a ULST window in an absence of detecting one or more downlink transmissions from the base station within a specified time period as described above with reference toFIGS. 2-4. In certain examples, the operations of block1525may be performed by the LBT component as described with reference toFIGS. 6 and 7.

At block1530, the UE115may include the identified data in the uplink transmission associated with the identified data as described above with reference toFIGS. 2-4. In certain examples, the operations of block1530may be performed by the uplink transmission generating component as described with reference toFIGS. 6 and 7.

FIG. 16shows a flowchart illustrating a method1600for ULST techniques using a contention-based radio frequency spectrum in accordance with various aspects of the present disclosure. The operations of method1600may be implemented by a device such as a base station105or its components as described with reference toFIGS. 1, 2, and 4. For example, the operations of method1600may be performed by the base station ULST manager as described herein. In some examples, the base station105may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the base station105may perform aspects of the functions described below using special-purpose hardware.

At block1605, the base station105may transmit one or more downlink transmissions associated with an LBT frame to at least one UE as described above with reference toFIGS. 2-4. In certain examples, the operations of block1605may be performed by the downlink transmission component as described with reference toFIGS. 10 and 11.

At block1610, the base station105may configure a ULST window that is non-overlapping with the LBT frame as described above with reference toFIGS. 2-4. In certain examples, the operations of block1610may be performed by the ULST window component as described with reference toFIGS. 10 and 11.

At block1615, the base station105may monitor for uplink transmissions from one or more UEs during the ULST window as described above with reference toFIGS. 2-4.

In certain examples, the operations of block1615may be performed by the uplink monitoring component as described with reference toFIGS. 10 and 11.

FIG. 17shows a flowchart illustrating a method1700for ULST techniques using a contention-based radio frequency spectrum in accordance with various aspects of the present disclosure. The operations of method1700may be implemented by a device such as a base station105or its components as described with reference toFIGS. 1, 2, and 4. For example, the operations of method1700may be performed by the base station ULST manager as described herein. In some examples, the base station105may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the base station105may perform aspects of the functions described below using special-purpose hardware.

At block1705, the base station105may transmit one or more downlink transmissions associated with an LBT frame to at least one UE as described above with reference toFIGS. 2-4. In certain examples, the operations of block1705may be performed by the downlink transmission component as described with reference toFIGS. 10 and 11.

At block1710, the base station105may configure a ULST window that is non-overlapping with the LBT frame as described above with reference toFIGS. 2-4. In certain examples, the operations of block1710may be performed by the ULST window component as described with reference toFIGS. 10 and 11.

At block1715, the base station105may configure a size threshold for transmitting user data in uplink transmissions during the ULST window as described above with reference toFIGS. 2-4. In certain examples, the operations of block1715may be performed by the data size component as described with reference toFIGS. 10 and 11.

At block1720, the base station105may monitor for uplink transmissions from one or more UEs during the ULST window as described above with reference toFIGS. 2-4. In certain examples, the operations of block1720may be performed by the uplink monitoring component as described with reference toFIGS. 10 and 11.

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

Base stations may include or may be referred to by those skilled in the art as a base transceiver station, a radio base station, an access point (AP), a radio transceiver, a NodeB, eNodeB (eNB), Home NodeB, a Home eNodeB, or some other suitable terminology. The geographic coverage area for a base station may be divided into sectors making up only a portion of the coverage area. The wireless communications system or systems described herein may include base stations of different types (e.g., macro or small cell base stations). The UEs described herein may be able to communicate with various types of base stations and network equipment including macro eNBs, small cell eNBs, relay base stations, and the like. There may be overlapping geographic coverage areas for different technologies. In some cases, different coverage areas may be associated with different communication technologies. In some cases, the coverage area for one communication technology may overlap with the coverage area associated with another technology. Different technologies may be associated with the same base station, or with different base stations.

The downlink transmissions described herein may also be called forward link transmissions while the uplink transmissions may also be called reverse link transmissions. Each communication link described herein including, for example, wireless communications system100and200ofFIGS. 1 and 2may include one or more carriers, where each carrier may be a signal made up of multiple sub-carriers (e.g., waveform signals of different frequencies). Each modulated signal may be sent on a different sub-carrier and may carry control information (e.g., reference signals, control channels, etc.), overhead information, user data, etc. The communication links described herein (e.g., communication links125ofFIG. 1) may transmit bidirectional communications using frequency division duplex (FDD) (e.g., using paired spectrum resources) or TDD operation (e.g., using unpaired spectrum resources). Frame structures may be defined for FDD (e.g., frame structure type 1) and TDD (e.g., frame structure type 2).

Thus, aspects of the disclosure may provide for ULST techniques using a contention-based radio frequency spectrum. It should be noted that these methods describe possible implementations, and that the operations and the steps may be rearranged or otherwise modified such that other implementations are possible. In some examples, aspects from two or more of the methods may be combined.

The various illustrative blocks and modules described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a digital signal processor (DSP), an ASIC, an field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration). 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, different types of ICs may be used (e.g., Structured/Platform ASICs, an FPGA, or another semi-custom IC), 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, with instructions embodied in a memory, formatted to be executed by one or more general or application-specific processors.