Receiver-side enhanced clear channel assessment for unlicensed bands

Abstract

Methods, systems, and devices for wireless communications are described. A first wireless device may receive a clear channel assessment trigger from a second wireless device, the clear channel assessment trigger being associated with a data transmission by the second wireless device. The first wireless device may send feedback information for the clear channel assessment trigger based at least in part on a result of a first clear channel assessment procedure. The first wireless device may receive a data transmission based at least in part on the feedback information for the first clear channel assessment procedure. The first wireless device may send feedback information for the data transmission based at least in part on a result of a second clear channel assessment procedure, wherein the first clear channel assessment procedure has a first duration that is longer than a second duration for the second clear channel assessment procedure.

Description

[0001] Cross-references

[0002] This patent application claims the benefit of U.S. Provisional Patent Application No. 62 / 972,614, filed by SUN et al. on February 10, 2020, entitled “RECEIVER SIDE ENHANCED CLEAR CHANNEL ASSESSMENT FOR UNLICENSED BAND,” and U.S. Patent Application No. 17 / 170,232, filed by SUN et al. on February 8, 2021, entitled “RECEIVER SIDE ENHANCED CLEAR CHANNEL ASSESSMENT FOR UNLICENSED BAND,” each of which has been assigned to the assignee of this application. Technical Field

[0003] The following description generally relates to wireless communications and, more particularly, to receiver-side enhanced clear channel assessment (eCCA) for unlicensed bands. Background Art

[0004] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcast, etc. These systems may be able to support communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of such multiple access systems include fourth generation (4G) systems (such as long term evolution (LTE) systems, improved LTE (LTE-A) systems, or LTE-A Pro systems) and fifth generation (5G) systems (which may be referred to as new radio (NR) systems). These systems may use techniques such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiplexing (OFDMA), or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM). A wireless multiple access communication system may include one or more base stations or one or more network access nodes, each base station or network access node simultaneously supporting communication for multiple communication devices (which may be further referred to as user equipment (UE)). Summary of the invention

[0005] The described techniques relate to improved methods, systems, devices, and apparatuses for supporting receiver-side enhanced clear channel assessment (eCCA) for unlicensed bands. In general, the described techniques prepare for a receiver-side long clear channel assessment (CCA) process (such as an eCCA process), while taking into account a short CCA process (e.g., a one-time or category-2 listen-before-talk (LBT) process) prior to control signaling transmission. For example, and in the downlink, a base station (e.g., the second wireless device in this example) may perform a short CCA process before sending a CCA trigger to a user equipment (UE) (e.g., the first wireless device in this example). The CCA trigger may schedule a downlink transmission for the UE, and / or may schedule the UE to send a feedback signal (e.g., an acknowledgement / negative acknowledgement (ACK / NACK), or a simpler A / N transmission) for the CCA trigger. The UE may receive a CCA trigger from a base station, and perform a long CCA process (e.g., an eCCA process) before sending feedback information for the CCA trigger (e.g., A / N feedback information for the CCA trigger). The base station may receive feedback information for a CCA trigger and then perform another short CCA process before sending a downlink transmission (e.g., data transmission) to the UE. The UE may then perform a short CCA process (e.g., a one-time LBT process) before sending feedback information for downlink transmission (e.g., A / N feedback information for data transmission). As another example in the uplink, the base station may perform a long CCA process (e.g., an eCCA process) before sending an uplink grant to the UE. The UE may receive an uplink grant and perform a short CCA process (e.g., a one-time LBT process) before sending an uplink transmission (e.g., uplink data transmission) to the base station.

[0006] In some aspects, one or more short CCA processes implemented at the base station and / or UE may be optional. For example, if the interval between receiving a transmission and performing the transmission is below a threshold (e.g., meets a threshold) in the time domain (e.g., less than X microseconds), the short CCA process may be omitted. In some aspects, this may include intervals between control signaling transmissions that are allowed to have short CCAs before performing the receiver-side eCCA process. After performing the receiver-side eCCA process, if the interval is longer than X microseconds, the interval between transmission bursts may be allowed to have short CCAs, for example, if the interval does not exceed X microseconds, the interval between transmission bursts may be allowed to have no short CCA. In this case, the interval may refer to a period of time when neither device is transmitting or receiving. The duration of these intervals may be a component in determining whether to perform a short CCA before a transmission, for example, depending on whether a receiver-side eCCA process has been performed.

[0007] A method of wireless communication is described. The method may include: receiving a CCA trigger at a first wireless device from a second wireless device, the CCA trigger being associated with a data transmission by the second wireless device; sending feedback information for the CCA trigger based on a result of a first CCA process; receiving the data transmission based on the feedback information for the first CCA process; and sending feedback information for the data transmission based on a result of a second CCA process, wherein the first CCA process has a first duration that is longer than a second duration for the second CCA process.

[0008] An apparatus for wireless communication is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to receive a CCA trigger at a first wireless device from a second wireless device, the CCA trigger being associated with a data transmission by the second wireless device; send feedback information for the CCA trigger based on a result of a first CCA process; receive the data transmission based on the feedback information for the first CCA process; and send feedback information for the data transmission based on a result of a second CCA process, wherein the first CCA process has a first duration that is longer than a second duration for the second CCA process.

[0009] Another apparatus for wireless communication is described. The apparatus may include means for: receiving, at a first wireless device, a CCA trigger from a second wireless device, the CCA trigger being associated with a data transmission by the second wireless device; sending feedback information for the CCA trigger based on a result of a first CCA process; receiving a data transmission based on the feedback information for the first CCA process; and sending feedback information for the data transmission based on a result of a second CCA process, wherein the first CCA process has a first duration that is longer than a second duration for the second CCA process.

[0010] A non-transitory computer-readable medium storing code for wireless communication is described. The code may include instructions executable by a processor to: receive a CCA trigger at a first wireless device from a second wireless device, the CCA trigger associated with a data transmission by the second wireless device; send feedback information for the CCA trigger based on a result of a first CCA process; receive a data transmission based on the feedback information for the first CCA process; and send feedback information for the data transmission based on a result of a second CCA process, wherein the first CCA process has a first duration that is longer than a second duration for the second CCA process.

[0011] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, sending feedback information for a CCA trigger based on a result of a first CCA process may include operations, features, units, or instructions for sending feedback information if the first CCA process can succeed.

[0012] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: determining that a first wireless device has data for transmission to a second wireless device; and multiplexing the data with feedback information triggered for a first CCA in the same transmission burst to the second wireless device.

[0013] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for determining a channel occupancy time for data transmission based on a CCA trigger.

[0014] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: determining a duration of an interval between receiving a data transmission and sending feedback information for the data transmission based on a CCA trigger; and selecting a second duration for a second CCA process based on the interval duration.

[0015] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for determining a first duration for a first CCA procedure based on a CCA trigger.

[0016] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: receiving a resource allocation for sending feedback information for a CCA trigger; and determining a first duration of a first CCA process based on the resource allocation for sending feedback information for a CCA trigger.

[0017] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for determining whether an interval period between receiving a data transmission and sending feedback information for the data transmission satisfies a threshold, wherein a second channel assessment process may be performed based on the interval period satisfying the threshold.

[0018] A method of wireless communication is described. The method may include: sending a CCA trigger to a first wireless device based on a result of a first CCA process, the CCA trigger being associated with a data transmission by a second wireless device; receiving feedback information for the CCA trigger from the first wireless device; sending a data transmission to the first wireless device based on a result of a second CCA process and in response to the feedback information for the CCA trigger; and receiving feedback information for the data transmission from the first wireless device.

[0019] An apparatus for wireless communication is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to send a CCA trigger to a first wireless device based on a result of a first CCA process, the CCA trigger being associated with a data transmission by a second wireless device; receive feedback information for the CCA trigger from the first wireless device; send a data transmission to the first wireless device based on a result of a second CCA process and in response to the feedback information for the CCA trigger; and receive feedback information for the data transmission from the first wireless device.

[0020] Another apparatus for wireless communication is described. The apparatus may include means for: sending a CCA trigger to a first wireless device based on a result of a first CCA process, the CCA trigger being associated with a data transmission by a second wireless device; receiving feedback information for the CCA trigger from the first wireless device; sending a data transmission to the first wireless device based on a result of a second CCA process and in response to the feedback information for the CCA trigger; and receiving feedback information for the data transmission from the first wireless device.

[0021] A non-transitory computer-readable medium storing code for wireless communication is described. The code may include instructions executable by a processor to: send a CCA trigger to a first wireless device based on a result of a first CCA process, the CCA trigger being associated with a data transmission by a second wireless device; receive feedback information for the CCA trigger from the first wireless device; send a data transmission to the first wireless device based on a result of a second CCA process and in response to the feedback information for the CCA trigger; and receive feedback information for the data transmission from the first wireless device.

[0022] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, sending a CCA trigger may include operations, features, means, or instructions for sending a CCA trigger to trigger data transmission to the first wireless device if the first CCA process may be successful.

[0023] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: determining that a first wireless device has data for transmission to a second wireless device; and receiving data multiplexed with feedback information triggered for a first CCA in the same transmission burst from the first wireless device.

[0024] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for selecting a first duration for a first CCA process based on data, wherein the first duration may be longer than a second duration for a second CCA process.

[0025] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, means, or instructions for determining a channel occupancy time for data transmission based on the first CCA process.

[0026] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: identifying a duration of a third CCA process for the first wireless device to perform before sending feedback information for a CCA trigger; selecting a resource allocation for the first wireless device for sending feedback information for a CCA trigger based on the duration for the third CCA process; and sending the resource allocation to the first wireless device.

[0027] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for determining that an interference level for a channel used to communicate with a first wireless device may have a threshold change rate, wherein a second CCA process may be performed based on the threshold change rate.

[0028] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for determining whether an interval period between receiving feedback information triggered for a CCA and sending a data transmission satisfies a threshold, wherein a second CCA process may be performed based on the interval period satisfying the threshold. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1

[0013] An example of a system for wireless communications that supports receiver-side enhanced clear channel assessment (eCCA) for unlicensed bands is shown in accordance with aspects of the present disclosure.

[0030] Figure 2 Examples of channel occupation time (CoT) configurations that support receiver-side eCCA for unlicensed bands are shown in accordance with aspects of the present disclosure.

[0031] Figure 3 Examples of CoT configurations that support receiver-side eCCA for unlicensed bands are shown according to aspects of the present disclosure.

[0032] Figure 4 An example of a process for supporting receiver-side eCCA for unlicensed bands is shown according to aspects of the present disclosure.

[0033] Figure 5 and Figure 6 A block diagram of a device supporting receiver-side eCCA for unlicensed bands is shown in accordance with aspects of the present disclosure.

[0034] Figure 7 A block diagram of a communication manager supporting receiver-side eCCA for unlicensed bands is shown in accordance with aspects of the present disclosure.

[0035] Figure 8 A schematic diagram of a system including a user equipment (UE) supporting receiver-side eCCA for unlicensed bands is shown in accordance with aspects of the present disclosure.

[0036] Fig. 9 A schematic diagram of a system including a base station supporting receiver-side eCCA for unlicensed bands is shown in accordance with aspects of the present disclosure.

[0037] Figures 10 to 14 A flow chart illustrating a method of supporting receiver-side eCCA for unlicensed bands is shown in accordance with aspects of the present disclosure. DETAILED DESCRIPTION

[0038] Wireless communication systems may operate in the millimeter wave (mmW) frequency range (e.g., 28 GHz, 40 GHz, 60 GHz, etc.). Wireless communications at these frequencies may be associated with increased signal attenuation (e.g., path loss), which may be affected by various factors such as temperature, atmospheric pressure, diffraction, etc. Therefore, signal processing techniques (such as beamforming) may be used to coherently combine energy and overcome path losses at these frequencies. Due to the increased amount of path loss in mmW communication systems, transmissions from base stations and / or user equipment (UE) may be beamformed. In addition, a receiving device may use beamforming techniques to configure an antenna and / or antenna array so that transmissions are received in a directional manner.

[0039] For mmW links, the transmitting device and the receiving device may experience very different interference / channel performance environments. Therefore, some wireless communication systems are configured so that the receiving device (e.g., UE) is given more protection than the transmitting device (e.g., base station). In some aspects, giving the receiving device more protection may include: the receiving device implements a channel clearing process (e.g., such as an enhanced clear channel assessment (eCCA) process) before sending a confirmation feedback transmission (e.g., feedback information) to the base station. Focusing on the channel clearing process design (e.g., listen before talk (LBT) design) can avoid unnecessary backoff at the base station while still protecting the receiving device. In some designs, the duration or length of the channel clearing process (e.g., eCCA process) can be explicitly indicated to the UE by the base station.

[0040] Various aspects of the present disclosure are initially described in the context of a wireless communication system. In general, the described techniques prepare for a receiver-side long clear channel assessment (CCA) process (such as an eCCA process), while taking into account a short CCA process (e.g., a one-time or category-2 LBT process) prior to control signaling transmission. For example, and in the downlink, a base station (e.g., the second wireless device in this example) may perform a short CCA process before sending a CCA trigger to a UE (e.g., the first wireless device in this example). The CCA trigger may schedule a downlink transmission for the UE, and / or may schedule the UE to send a feedback signal (e.g., an acknowledgement / negative acknowledgement (ACK / NACK), or a simpler A / N transmission) for the CCA trigger. The UE may receive a CCA trigger from the base station, and perform a long CCA process (e.g., an eCCA process) before sending feedback information for the CCA trigger (e.g., A / N feedback information for the CCA trigger). The base station may receive feedback information for the CCA trigger, and then perform another short CCA process before sending a downlink transmission (e.g., a data transmission) to the UE. The UE may then perform a short CCA procedure (e.g., a one-time LBT procedure) before sending feedback information for downlink transmission (e.g., A / N feedback information for data transmission). As another example in the uplink, the base station may perform a long CCA procedure (e.g., an eCCA procedure) before sending an uplink grant to the UE. The UE may receive an uplink grant and perform a short CCA procedure (e.g., a one-time LBT procedure) before sending an uplink transmission (e.g., uplink data transmission) to the base station.

[0041] In some aspects, one or more short CCA processes implemented at the base station and / or UE may be optional. For example, if the interval between receiving a transmission and performing the transmission is below a threshold (e.g., meets a threshold) in the time domain (e.g., less than X microseconds), the short CCA process may be omitted. In some aspects, this may include allowing the interval between control signaling transmissions to have a short CCA before performing the receiver-side eCCA process. After performing the receiver-side eCCA process, if the interval is longer than X microseconds, the interval between transmission bursts may be allowed to have a short CCA, for example, if the interval does not exceed X microseconds, the interval between transmission bursts may be allowed to have no short CCA. In this context, an interval may refer to a period of time during which neither device is transmitting or receiving. The duration of these intervals may be a component in determining whether to perform a short CCA before a transmission, for example, depending on whether a receiver-side eCCA process has been performed.

[0042] Various aspects of the present disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flow charts relating to receiver-side eCCA for unlicensed bands.

[0043] Figure 1 An example of a wireless communication system 100 that supports receiver-side eCCA for unlicensed bands is shown according to various aspects of the present disclosure. The wireless communication system 100 may include one or more base stations 105, one or more UEs 115, and a core network 130. In some examples, the wireless communication system 100 may be a long term evolution (LTE) network, an improved LTE (LTE-A) network, an LTE-A Pro network, or a new radio (NR) network. In some examples, the wireless communication system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission-critical) communications, low-latency communications, communications with low-cost and low-complexity devices, or any combination thereof.

[0044] The base stations 105 may be dispersed throughout a geographic area to form the wireless communication system 100, and may be devices in different forms or with different capabilities. The base stations 105 and the UEs 115 may communicate wirelessly via one or more communication links 125. Each base station 105 may provide a coverage area 110 over which the UEs 115 and the base stations 105 may establish one or more communication links 125. The coverage area 110 may be an example of a geographic area over which the base stations 105 and the UEs 115 may support transmission of signals according to one or more radio access technologies.

[0045] The UEs 115 may be dispersed throughout the coverage area 110 of the wireless communication system 100, and each UE 115 may be stationary, mobile, or both at different times. The UEs 115 may be devices in different forms or with different capabilities. Figure 1 Some example UEs 115 are shown in FIG. 1 . The UEs 115 described herein may be able to communicate with various types of devices such as other UEs 115, base stations 105, or network devices (e.g., core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network devices), such as Figure 1 as shown in .

[0046] The base stations 105 may communicate with the core network 130, or with each other, or both. For example, the base stations 105 may be coupled to the core network 130 via one or more backhaul links 120 (e.g., via S1, N2, N3, or other interfaces). The base stations 105 may communicate with each other via the backhaul links 120 (e.g., via X2, Xn, or other interfaces) directly (e.g., directly between the base stations 105) or indirectly (e.g., via the core network 130), or both. In some examples, the backhaul links 120 may be or include one or more wireless links.

[0047] One or more of the base stations 105 described herein may include or be referred to by a person of ordinary skill in the art as a base station transceiver, a radio base station, an access point, a radio transceiver, a NodeB, an evolved NodeB (eNodeB, eNB), a next generation NodeB or a Gigabit NodeB (any of which may be referred to as a gNB), a Home NodeB, a Home Advanced NodeB or other appropriate terms.

[0048] UE 115 may include or may be referred to as a mobile device, a wireless device, a remote device, a handheld device or a user device, or some other appropriate terminology, where "device" may also be referred to as a unit, a station, a terminal or a client, as well as other examples. UE 115 may also include or may be referred to as a personal electronic device, such as a cellular phone, a personal digital assistant (PDA), a tablet computer, a laptop computer, or a personal computer. In some examples, UE 115 may include or may be referred to as a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine type communication (MTC) device, as well as other examples, which may be implemented in various items such as home appliances, or vehicles, meters, and other examples.

[0049] The UE 115 described herein may be able to communicate with various types of devices, such as other UEs 115 that may sometimes act as relays, as well as base stations 105 and network devices including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, among other examples. Figure 1 as shown in .

[0050] The UE 115 and the base station 105 can communicate with each other wirelessly via one or more communication links 125 through one or more carriers. The term "carrier" can refer to a set of radio frequency spectrum resources with a defined physical layer structure for supporting the communication link 125. For example, the carrier used for the communication link 125 may include a portion of the radio frequency spectrum band (e.g., bandwidth portion (BWP)) that operates according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical layer channel can carry acquisition signaling (e.g., synchronization signals, system information), control signaling for coordinating operations for the carrier, user data, or other signaling. The wireless communication system 100 can use carrier aggregation or multi-carrier operation to support communication with the UE 115. According to the carrier aggregation configuration, the UE 115 can be configured with multiple downlink component carriers and one or more uplink component carriers. Carrier aggregation can be used with both frequency division duplex (FDD) and time division duplex (TDD) component carriers.

[0051] In some examples (e.g., in a carrier aggregation configuration), a carrier may also have acquisition signaling or control signaling that coordinates operations with respect to other carriers. A carrier may be associated with a frequency channel (e.g., an Evolved Universal Mobile Telecommunications System Terrestrial Radio Access (E-UTRA) Absolute Radio Frequency Channel Number (EARFCN)) and may be located according to a channel raster used for discovery by UE 115. A carrier may operate in a standalone mode, where initial acquisition and connection may be performed by UE 115 via the carrier, or a carrier may operate in a non-standalone mode, where connections are anchored using different carriers (e.g., of the same or different radio access technologies).

[0052] The communication link 125 shown in the wireless communication system 100 may include an uplink transmission from the UE 115 to the base station 105, or a downlink transmission from the base station 105 to the UE 115. A carrier may carry downlink or uplink communications (e.g., in FDD mode) or may be configured to carry both downlink and uplink communications (e.g., in TDD mode).

[0053] A carrier may be associated with a particular bandwidth of a radio frequency spectrum, and in some examples, a carrier bandwidth may be referred to as a "system bandwidth" of a carrier or wireless communication system 100. For example, a carrier bandwidth may be one of a number of determined bandwidths for a carrier of a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 megahertz (MHz)). A device of the wireless communication system 100 (e.g., a base station 105, a UE 115, or both) may have a hardware configuration that supports communication on a particular carrier bandwidth, or may be configured to support communication on one of a set of carrier bandwidths. In some examples, the wireless communication system 100 may include a base station 105 or a UE 115 that supports simultaneous communication via carriers associated with multiple carrier bandwidths. In some examples, each served UE 115 may be configured to operate on a portion (e.g., a subband, a BWP) or all of a carrier bandwidth.

[0054] The signal waveform transmitted through the carrier wave may be composed of multiple subcarriers (e.g., using a multicarrier modulation (MCM) technique such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)). In a system employing MCM techniques, a resource element may include a symbol period (e.g., the duration of a modulation symbol) and a subcarrier, where the symbol period and the subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both). Therefore, the more resource elements received by the UE 115 and the higher the order of the modulation scheme, the higher data rate may be used for the UE 115. Wireless communication resources may refer to a combination of radio frequency spectrum resources, time resources, and spatial resources (e.g., spatial layers or beams), and the use of multiple spatial layers may further increase the data rate or data integrity used for communications with the UE 115.

[0055] One or more numerologies may be supported for a carrier, where the numerology may include a subcarrier spacing (Δf) and a cyclic prefix. A carrier may be divided into one or more BWPs with the same or different numerologies. In some examples, a UE 115 is configured with multiple BWPs. In some examples, a single BWP may be active for a carrier at a given time, and communications for a UE 115 may be limited to one or more active BWPs.

[0056] The time interval for the base station 105 or the UE 115 may be expressed in multiples of a basic time unit, which may refer to, for example, T s =1 / (Δf max ·N f) seconds sampling period, where Δf max It can indicate the maximum supported subcarrier spacing, and N f The maximum supported discrete Fourier transform (DFT) size may be indicated. The time intervals of the communication resources may be organized according to radio frames, each radio frame having a specified duration (e.g., 10 milliseconds (ms)). Each radio frame may be identified by a system frame number (SFN) (e.g., ranging from 0 to 1023).

[0057] Each frame may include multiple consecutively numbered subframes or time slots, and each subframe or time slot may have the same duration. In some examples, a frame may be divided into subframes (e.g., in the time domain), and each subframe may be further divided into multiple time slots. Alternatively, each frame may include a variable number of time slots, and the number of time slots may depend on the subcarrier spacing. Each time slot may include multiple symbol periods (e.g., depending on the length of the cyclic prefix appended to each symbol period). In some wireless communication systems 100, a time slot may be further divided into multiple micro-time slots containing one or more symbols. In addition to the cyclic prefix, each symbol period may contain one or more (e.g., N f ) sampling periods. The duration of a symbol period may depend on the subcarrier spacing or the operating band.

[0058] A subframe, slot, mini-slot, or symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communication system 100, and may be referred to as a transmission time interval (TTI). In some examples, the TTI duration (e.g., the number of symbol periods in a TTI) may be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communication system 100 may be dynamically selected (e.g., in a burst of a shortened TTI (sTTI)).

[0059] Physical channels may be multiplexed on a carrier according to various techniques. Physical control channels and physical data channels may be multiplexed on a downlink carrier, for example, using one or more of a time division multiplexing (TDM) technique, a frequency division multiplexing (FDM) technique, or a hybrid TDM-FDM technique. A control region (e.g., a control resource set (CORESET)) for a physical control channel may be defined by a plurality of symbol periods and may extend across a system bandwidth or a subset of a system bandwidth of a carrier. One or more control regions (e.g., CORESETs) may be configured for a set of UEs 115. For example, one or more of the UEs 115 may monitor or search a control region for control information according to one or more search space sets, and each search space set may include one or more control channel candidates at one or more aggregation levels arranged in a cascaded manner. An aggregation level for a control channel candidate may refer to the number of control channel resources (e.g., control channel elements (CCEs)) associated with coded information for a control information format having a given payload size. The search space sets may include a common search space set configured for transmitting control information to multiple UEs 115 and a UE-specific search space set for transmitting control information to a specific UE 115 .

[0060] Each base station 105 can provide communication coverage via one or more cells (e.g., macro cells, small cells, hot spots or other types of cells or any combination thereof). The term "cell" can refer to a logical communication entity used for communication with the base station 105 (e.g., via a carrier), and can be associated with an identifier (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID) or other) used to distinguish adjacent cells. In some examples, a cell can also refer to a geographic coverage area 110 or a portion (e.g., a sector) of a geographic coverage area 110 on which a logical communication entity operates. Depending on various factors (such as the capabilities of the base station 105), such a cell can range from a smaller area (e.g., a structure, a subset of a structure) to a larger area. For example, a cell can be or include a building, a subset of a building, or an external space between or overlapping a geographic coverage area 110, as well as other examples.

[0061] A macro cell typically covers a relatively large geographic area (e.g., several kilometers in radius), and may allow unrestricted access by a UE 115 with a service subscription to a network provider that supports the macro cell. A small cell may be associated with a lower power base station 105 than a macro cell, and the small cell may operate in the same or different (e.g., licensed, unlicensed) frequency band as the macro cell. A small cell may provide unrestricted access to a UE 115 with a service subscription to a network provider, or may provide restricted access to a UE 115 associated with the small cell (e.g., a UE 115 in a closed subscriber group (CSG), a UE 115 associated with a user in a residence or office). A base station 105 may support one or more cells, and may also support communications on one or more cells using one or more component carriers.

[0062] In some examples, an operator may support multiple cells, and different cells may be configured according to different protocol types (e.g., MTC, narrowband IoT (NB-IoT), enhanced mobile broadband (eMBB)) that can provide access to different types of devices.

[0063] In some examples, the base stations 105 may be mobile and, therefore, provide communication coverage for mobile geographic coverage areas 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, but the different geographic coverage areas 110 may be supported by the same base station 105. In other examples, overlapping geographic coverage areas 110 associated with different technologies may be supported by different base stations 105. The wireless communication system 100 may include, for example, a heterogeneous network in which different types of base stations 105 provide coverage for various geographic coverage areas 110 using the same or different radio access technologies.

[0064] The wireless communication system 100 may support synchronous operation or asynchronous operation. For synchronous operation, the base stations 105 may have similar frame timing, and transmissions from different base stations 105 may be approximately aligned in time. For asynchronous operation, the base stations 105 may have different frame timing, and transmissions from different base stations 105 may not be aligned in time in some examples. The techniques described herein may be used for either synchronous operation or asynchronous operation.

[0065] Some UEs 115, such as MTC or IoT devices, may be low-cost or low-complexity devices and may provide for automated communication between machines (e.g., via machine-to-machine (M2M) communication). M2M communication or MTC may refer to data communication technology that allows devices to communicate with each other or with a base station 105 without human intervention. In some examples, M2M communication or MTC may include communication from a device integrated with a sensor or meter that measures or captures information and relays such information to a central server or application that utilizes the information or presents the information to a person interacting with the application. Some UEs 115 may be designed to collect information or implement automated behavior of a machine or other device. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based commercial billing.

[0066] Some UEs 115 may be configured to employ an operating mode that reduces power consumption, such as half-duplex communication (e.g., a mode that supports unidirectional communication via transmission or reception but does not support simultaneous transmission and reception). In some examples, half-duplex communication may be performed at a reduced peak rate. Other power saving techniques for UE 115 include entering a power saving deep sleep mode when not engaged in active communications, operating over a limited bandwidth (e.g., according to narrowband communications), or a combination of these techniques. For example, some UEs 115 may be configured to operate using a narrowband protocol type that is associated with a defined portion or range (e.g., a set of subcarriers or resource blocks (RBs)) within a carrier, within a guard band of a carrier, or outside a carrier.

[0067] The wireless communication system 100 can be configured to support ultra-reliable communication or low-latency communication or various combinations thereof. For example, the wireless communication system 100 can be configured to support ultra-reliable low-latency communication (URLLC) or mission-critical communication. UE115 can be designed to support ultra-reliable, low-latency or critical functions (e.g., mission-critical functions). Ultra-reliable communication can include private communication or group communication, and can be supported by one or more mission-critical services (such as mission-critical push-to-talk (MCPTT), mission-critical video (MCVideo), or mission-critical data (MCData). Support for mission-critical functions can include prioritizing services, and mission-critical services can be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, mission-critical, and ultra-reliable low-latency can be used interchangeably in this article.

[0068] In some examples, UE 115 may also be able to communicate directly with other UE 115 via a device-to-device (D2D) communication link 135 (e.g., using a peer-to-peer (P2P) or D2D protocol). One or more UEs 115 utilizing D2D communication may be within a geographic coverage area 110 of a base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of the base station 105, or otherwise fail to receive transmissions from the base station 105. In some examples, a group of UEs 115 communicating via D2D communication may utilize a one-to-many (1:M) system in which each UE 115 transmits to each other UE 115 in the group. In some examples, the base station 105 facilitates scheduling of resources for D2D communication. In other cases, D2D communication is performed between UEs 115 without involving the base station 105.

[0069] In some systems, the D2D communication link 135 can be an example of a communication channel (e.g., a sidelink communication channel) between vehicles (e.g., UE 115). In some examples, vehicles can communicate using vehicle-to-everything (V2X) communication, vehicle-to-vehicle (V2V) communication, or some combination of these. Vehicles can signal information related to traffic conditions, signal scheduling, weather, safety, emergency situations, or any other information related to the V2X system. In some examples, vehicles in a V2X system can communicate with roadside infrastructure (such as roadside units), or communicate with a network via one or more network nodes (e.g., base station 105) using vehicle-to-network (V2N) communication, or both.

[0070] The core network 130 may provide user authentication, access permission, tracking, Internet Protocol (IP) connection, and other access, routing or mobility functions. The core network 130 may be an evolved packet core (EPC) or a 5G core (5GC), which may include at least one control plane entity (e.g., a mobility management entity (MME), an access and mobility management function (AMF)) for managing access and mobility, and at least one user plane entity (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), or a user plane function (UPF)) for routing packets or interconnecting to an external network. The control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management for UE 115 served by a base station 105 associated with the core network 130. User IP packets may be transmitted via a user plane entity, which may provide IP address allocation and other functions. The user plane entity may be connected to a network operator IP service 150. Operator IP services 150 may include access to the Internet, an intranet, an IP Multimedia Subsystem (IMS), or packet-switched streaming services.

[0071] Some of the network devices (such as base stations 105) may include subcomponents such as access network entities 140, which may be examples of access node controllers (ANCs). Each access network entity 140 may communicate with the UE 115 through one or more other access network transport entities 145 (which may be referred to as radio heads, smart radio heads, or transmit / receive points (TRPs)). Each access network transport entity 145 may include one or more antenna panels. In some configurations, the various functions of each access network entity 140 or base station 105 may be distributed across various network devices (e.g., radio heads and ANCs), or combined in a single network device (e.g., base station 105).

[0072] The wireless communication system 100 may operate using one or more frequency bands, typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). Typically, the region from 300 MHz to 3 GHz is referred to as the very high frequency (UHF) region or decimeter band, since the wavelengths range from approximately one decimeter to one meter in length. UHF waves may be blocked or redirected by buildings and environmental features, but the waves may penetrate structures sufficiently for a macro cell to provide service to a UE 115 located indoors. Transmission of UHF waves may be associated with smaller antennas and shorter distances (e.g., less than 100 kilometers) than transmission using the lower frequencies and longer wavelengths of the high frequency (HF) or very high frequency (VHF) portions of the spectrum below 300 MHz.

[0073] The wireless communication system 100 may also operate in a super high frequency (SHF) region using a frequency band from 3 GHz to 30 GHz (also referred to as a centimeter band), or in an extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz) (also referred to as a millimeter band). In some examples, the wireless communication system 100 may support millimeter wave (mmW) communications between the UE 115 and the base station 105, and the EHF antennas of the respective devices may be smaller and more compact than UHF antennas. In some examples, this may facilitate the use of antenna arrays within the device. However, the propagation of EHF transmissions may suffer from greater atmospheric attenuation and shorter distances than SHF or UHF transmissions. The techniques disclosed herein may be employed across transmissions using one or more different frequency regions, and the designated use of frequency bands across these frequency regions may vary from country to country or regulatory agency.

[0074] The wireless communication system 100 can utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communication system 100 can employ license assisted access (LAA), LTE unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz industrial, scientific and medical (ISM) band. When operating in an unlicensed radio frequency spectrum band, devices such as base stations 105 and UE 115 can employ carrier sensing for conflict detection and avoidance. In some examples, operation in an unlicensed band can be based on a carrier aggregation configuration in combination with component carriers operating in a licensed band (e.g., LAA). Operations in an unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, as well as other examples.

[0075] The base station 105 or UE 115 may be equipped with multiple antennas, which may be used to employ technologies such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. The antennas of the base station 105 or UE 115 may be located within one or more antenna arrays or antenna panels, which may support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly (such as an antenna tower). In some examples, the antennas or antenna arrays associated with the base station 105 may be located at different geographical locations. The base station 105 may have an antenna array with a number of rows and columns of antenna ports, which the base station 105 may use to support beamforming for communications with the UE 115. Similarly, the UE 115 may have one or more antenna arrays, which may support various MIMO or beamforming operations. Additionally or alternatively, the antenna panel may support radio frequency beamforming for signals sent via the antenna ports.

[0076] The base station 105 or UE 115 can use MIMO communication to adopt multipath signal propagation, and to increase spectral efficiency by sending or receiving multiple signals via different spatial layers. Such a technology may be referred to as spatial multiplexing. Multiple signals may be, for example, sent by a transmitting device via different antennas or different combinations of antennas. Similarly, multiple signals may be received by a receiving device via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream, and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords). Different spatial layers may be associated with different antenna ports for channel measurement and reporting. MIMO technology includes single-user MIMO (SU-MIMO) and multi-user MIMO (MU-MIMO), wherein multiple spatial layers are sent to the same receiving device in SU-MIMO, and multiple spatial layers are sent to multiple devices in MU-MIMO.

[0077] Beamforming (which may also be referred to as spatial filtering, directional transmission, or directional reception) is a signal processing technique that may be used at a transmitting device or receiving device (e.g., base station 105, UE 115) to shape or control an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining signals transmitted via antenna elements of an antenna array so that some signals propagating in a particular orientation with respect to the antenna array experience constructive interference, while other signals experience destructive interference. Adjustments to signals transmitted via antenna elements may include the transmitting device or receiving device applying an amplitude offset, a phase offset, or both to signals carried via antenna elements associated with the device. Adjustments associated with each of the antenna elements may be defined by a set of beamforming weights associated with a particular orientation (e.g., with respect to an antenna array of a transmitting device or receiving device, or with respect to some other orientation).

[0078] The base station 105 or the UE 115 may use beam scanning techniques as part of a beamforming operation. For example, the base station 105 may use multiple antennas or antenna arrays (e.g., antenna panels) to perform beamforming operations for directional communication with the UE 115. Some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be sent multiple times by the base station 105 in different directions. For example, the base station 105 may send signals based on different sets of beamforming weights associated with different transmission directions. Transmissions in different beam directions may be used (e.g., by a transmitting device such as the base station 105 or a receiving device such as the UE 115) to identify a beam direction for later transmission or reception by the base station 105.

[0079] Some signals, such as data signals associated with a particular receiving device, may be transmitted by base station 105 in a single beam direction (e.g., a direction associated with a receiving device such as UE 115). In some examples, the beam direction associated with transmissions along a single beam direction may be determined based on signals transmitted in one or more beam directions. For example, UE 115 may receive one or more of the signals transmitted by base station 105 in different directions, and may report to base station 105 an indication of the signals received by UE 115 with the highest signal quality or other acceptable signal quality.

[0080] In some examples, transmission by a device (e.g., by a base station 105 or a UE 115) may be performed using multiple beam directions, and the device may use a combination of digital precoding or radio frequency beamforming to generate a combined beam for transmission (e.g., from the base station 105 to the UE 115). The UE 115 may report feedback indicating precoding weights for one or more beam directions, and the feedback may correspond to a configured number of beams across the system bandwidth or one or more subbands. The base station 105 may send a reference signal (e.g., a cell-specific reference signal (CRS), a channel state information reference signal (CSI-RS)), which may be precoded or unprecoded. The UE 115 may provide feedback for beam selection, which may be a precoding matrix indicator (PMI) or codebook-based feedback (e.g., a multi-panel type codebook, a linear combination type codebook, a port selection type codebook). Although these techniques are described with reference to signals sent by base station 105 in one or more directions, UE 115 may employ similar techniques for sending signals multiple times in different directions (e.g., for identifying a beam direction for subsequent transmission or reception by UE 115) or for sending signals in a single direction (e.g., for sending data to a receiving device).

[0081] A receiving device (e.g., UE 115) may try multiple reception configurations (e.g., directional listening) when receiving various signals (such as synchronization signals, reference signals, beam selection signals, or other control signals) from a base station 105. For example, a receiving device may try multiple reception directions by receiving via different antenna subarrays, by processing received signals according to different antenna subarrays, by receiving according to different reception beamforming weight sets (e.g., different directional listening weight sets) applied to signals received at multiple antenna elements of an antenna array, or by processing received signals according to different reception beamforming weight sets applied to signals received at multiple antenna elements of an antenna array, any of which may be referred to as "listening" according to different reception configurations or reception directions. In some examples, a receiving device may use a single reception configuration to receive along a single beam direction (e.g., when receiving a data signal). A single receive configuration may be aligned on a beam direction determined based on listening according to different receive configuration directions (e.g., a beam direction determined to have the highest signal strength, highest signal-to-noise ratio (SNR), or otherwise acceptable signal quality based on listening according to multiple beam directions).

[0082] The wireless communication system 100 may be a packet-based network that operates according to a layered protocol stack. In the user plane, communications at the bearer or packet data convergence protocol (PDCP) layer may be IP-based. The radio link control (RLC) layer may perform packet segmentation and reassembly to communicate through logical channels. The medium access control (MAC) layer may perform priority processing, as well as multiplexing of logical channels to transport channels. The MAC layer may also support retransmission at the MAC layer using error detection techniques, error correction techniques, or both, to improve link efficiency. In the control plane, the radio resource control (RRC) protocol layer may provide for the establishment, configuration, and maintenance of an RRC connection between a UE 115 and a base station 105 or a core network 130 that supports a radio bearer for user plane data. At the physical layer, a transport channel may be mapped to a physical channel.

[0083] UE 115 and base station 105 can support retransmission of data to increase the possibility of successfully receiving data. Hybrid automatic repeat request (HARQ) feedback is a technique for increasing the possibility of correctly receiving data through communication link 125. HARQ can include a combination of error correction (e.g., using cyclic redundancy check (CRC)), forward error correction (FEC) and retransmission (e.g., automatic repeat request (ARQ)). HARQ can improve the throughput at the MAC layer under poor radio conditions (e.g., low signal-to-noise ratio conditions). In some examples, the device can support same-slot HARQ feedback, where the device can provide HARQ feedback in the slot for data received in the previous symbol of a specific slot. In other cases, the device can provide HARQ feedback in a subsequent slot or according to some other time interval.

[0084] A first wireless device (e.g., a UE 115 and / or a base station 105 receiving a data transmission) may receive a CCA trigger at the first wireless device from a second wireless device, the CCA trigger being associated with a data transmission by the second wireless device. The first wireless device may send feedback information for the CCA trigger based at least in part on a result of a first CCA process. The first wireless device may receive the data transmission based at least in part on the feedback information for the first CCA process. The first wireless device may send feedback information for the data transmission based at least in part on a result of a second CCA process, wherein the first CCA process has a first duration that is longer than a second duration for the second CCA process.

[0085] A second wireless device (e.g., a UE 115 and / or a base station 105 sending a data transmission) may send a CCA trigger to the first wireless device based at least in part on a result of the first CCA process, the CCA trigger being associated with the data transmission by the second wireless device.

[0086] The second wireless device may receive feedback information for the CCA trigger from the first wireless device.The second wireless device may send a data transmission to the first wireless device based at least in part on a result of the second CCA process and in response to the feedback information for the CCA trigger.

[0087] The second wireless device may receive feedback information for the data transmission from the first wireless device.

[0088] Figure 2An example of a CoT configuration 200 that supports receiver-side eCCA for unlicensed bands is shown according to aspects of the present disclosure. In some examples, the CoT configuration 200 can implement aspects of the wireless communication system 100. The CoT configuration 200 can be implemented by a UE and / or a base station, where the UE and / or the base station can be examples of corresponding devices described herein. Generally, the CoT configuration 200 shows an example CoT configuration for downlink (DL) and uplink (UL) communications.

[0089] In energy detection-based LBT, a listening / sensing process (e.g., an eCCA process) is typically performed by a transmitting device before occupying the medium. If the medium is determined to be unavailable (e.g., found to be busy), the transmitter is silent (e.g., performs a backoff process and waits to perform its transmission). This means protecting ongoing transmissions at the expense of delaying the transmissions of competing nodes. For mmW links, the base station (e.g., the transmitting device in this example) and the UE (e.g., the receiving device in this example) may experience very different interference / channel performance environments. For example, the receiving device may be jammed (e.g., having high energy detection on the channel), while the transmitting device may not be jammed. Due to this mismatch, transmitter-side eCCA may be useless. Although the UE is generally described as a receiving device in the downlink example, it should be understood that the base station may be a receiving device in the uplink example.

[0090] Therefore, some wireless communication systems are configured such that a receiving device (e.g., a first wireless device, or a UE in this downlink example) is given more protection than a transmitting device (e.g., a base station). In some aspects, giving the receiving device more protection may include the receiving device implementing a channel clearing procedure (e.g., such as an eCCA procedure) before sending feedback information to the base station. Focusing the CCA procedure design (e.g., LBT design) at the receiving device may avoid unnecessary backoff at the base station while still protecting the receiving device.

[0091] In some aspects, this form of LBT design (e.g., receiver-side eCCA) is not focused solely on contention resolution. Instead, LBT can be used for current link verification. That is, the transmitting device can still transmit, but the transmission will only occur if it is beneficial to the receiver (e.g., if the receiver is able to receive the transmission). In other words, if the receiver cannot receive the signal due to a nearby jammer, the transmitting device will not send a long data burst. In this way, although the transmission of the jamming victim receiver is not muted, the situation where jamming (i.e., causing damage) occurs can be avoided, where the target receiver cannot properly receive the signal in the event of jamming.

[0092] Thus, aspects of the described technology apply an eCCA process (e.g., CAT-4CCA or LBT process) on the receiver side prior to data transmission, while allowing short control signaling (e.g., grants, A / N feedback information, etc.) with or without a short CCA process (e.g., one-time LBT / CAT-2LBT) prior to the eCCA. Short control signaling and the intervals therebetween can be counted toward the maximum allowed CoT. Before the eCCA process, intervals between control signaling are allowed to have CCA. After the eCCA process, if the interval between bursts does extend for more than X microseconds, the interval is allowed to have CCA, and if the interval does not exceed X microseconds (e.g., in one non-limiting example, X may be equal to 3μs), the intervals between bursts are allowed to have no CCA. The presence or absence of a short CCA process changes the requirements for timing constraints for communication.

[0093] For example, and starting with the downlink example, a base station (a transmitting device, which in this example may be referred to as a second wireless device) may perform a CCA procedure 205 (e.g., a one-time LBT procedure, a CAT-2 LBT procedure, etc.) before sending a grant 210 (e.g., a pre-grant (PG) for the UE, which may be a PDCCH DCI grant that serves as a CCA trigger). The grant 210 may schedule a feedback information transmission 220 and a data transmission 230 for the UE (a receiving device, which in this example may be referred to as a first wireless device). In some aspects, the grant 210 may indicate to the UE that a downlink burst (e.g., a data transmission 230) is forthcoming, e.g., the grant 210 may serve as an eCCA trigger for the UE, and may include an eCCA link parameter n for indicating the duration of the eCCA procedure 215. The grant 210 may be sent after the base station performs the CCA procedure 205 (e.g., a short or one-time / CAT-2 LBT / CCA procedure).

[0094] Thus, the UE may perform an eCCA procedure 215 (e.g., a full or CAT-4 LBT procedure) before sending feedback information transmission 220 to the base station. That is, if the eCCA procedure 215a is successful, the UE may send feedback information transmission 220 to the base station. Feedback information transmission 220 may also be considered as uplink control signaling that triggers the base station to send an actual downlink burst. The length or duration of the eCCA procedure 215 implemented at the receiving device may be indicated by the base station in the grant 210, for example using an eCCA length parameter n. In some aspects, the feedback information transmission 220 may be an ACK / NACK feedback transmission for the grant 210, for example confirming that the UE is able to receive and decode the grant 210.

[0095] Based on receiving the feedback information transmission 220, the base station may perform a CCA procedure 225 (e.g., a one-time LBT procedure) before performing a data transmission 230 to the UE. That is, the downlink burst may be sent after performing the CCA procedure 225 at the base station. Subsequently, the UE may perform a CCA procedure 235 (e.g., a one-time LBT procedure) before performing a second feedback information transmission 240 indicating whether the UE was able to successfully receive and decode the data transmission 230.

[0096] In some aspects, various options may be implemented for the downlink transmission scenarios discussed above.In one aspect, the spacing period between bursts may not need to be precisely controlled, such as not requiring CoT to be abandoned when the spacing period is greater than X microseconds within CoT.

[0097] In one option regarding the CCA process 205, the base station may use the CCA process 205 to initiate CoT, for example, to send a downlink pre-grant (grant 210). The CCA process 205 may increase the chances of finding an idle channel for the base station to receive the feedback information transmission 220 and / or the second feedback information transmission 240. If the CCA process 205 fails, the base station cannot listen in that direction (e.g., may not be able to communicate with the UE located in that direction), which may indicate that it is not worthwhile to attempt to perform a downlink transmission to the UE there. In another option regarding the CCA process 205, the base station may not perform the CCA process 205, for example, the wireless communication system may be configured so that control signaling (e.g., grant 210) may be performed without performing the CCA process 205.

[0098] In one option regarding the CCA process 225, this can support downlink bursts (e.g., data transmission 230) occurring within the CoT, but the data transmission 230 can be started with or without the CCA process 225. In one option, the CCA process 225 may not be performed (e.g., it may be skipped). For example, assuming that the interference will not change too quickly, the base station may send the data transmission 230 without performing the CCA process 225. For example, the base station may determine that the interference level for the channel has a certain threshold change rate (e.g., it will not change too quickly). Therefore, the CCA process 225 may be performed based on the threshold change rate for the interference level for the channel. In another option regarding the CCA process 225, the data transmission 230 may be started after performing the CCA process 225. For example, it may be safer to use the CCA process 225 to address the situation of interference changes. In the previous configuration, when the interval between the feedback information transmission 220 and the data transmission 230 is lower than the threshold (e.g., less than X microseconds), it is considered that the CCA process 225 can be omitted, because this will prevent other nodes from taking over the data transmission 230. However, this may not be applicable to mmW links, for example the directionality may prevent other nodes from detecting previous bursts.

[0099] Turning now to an example uplink scenario, in which the base station can be considered a receiving device, and the UE can be considered a transmitting device. Various aspects of the described technology can include the base station performing an eCCA process 250 before a short downlink burst (e.g., a control signal burst, such as an uplink grant 255). If the eCCA process 250 is successful, the base station can send a downlink trigger or an uplink grant to tell the UE to send an uplink data burst (e.g., an uplink data transmission 265). Based on receiving the uplink grant 255, this can signal the UE that a downlink trigger has been received, and the downlink trigger indicates that the UE is to send an uplink burst. Therefore, the UE can perform a CCA process 260 (e.g., a one-time or CAT-2LBT / CCA process) before sending an uplink data transmission 265 to the base station. That is, the uplink burst can be sent after the CCA process 260 is performed at the UE.

[0100] In some aspects, there may be some options to consider regarding uplink scenarios. For example, the base station is considered a receiving device in this scenario, and therefore the eCCA process 250 can be used to initiate CoT (e.g., without pre-grant). In some aspects, the CCA process 260 may be optional. For example, if there are future downlink bursts from the base station in the same CoT (e.g., in a multi-switch point or mixed uplink / downlink situation), the CCA process 260 may be performed. In some aspects, pre-grant may not be required at the base station, but pre-grant may be used for other purposes. For example, the base station may send an optional pre-grant to grant the UE uplink burst, and then send a downlink trigger for the grant after performing the eCCA process 250. The pre-grant may be used as an eCCA indicator, and includes an eCCA link parameter n. After receiving the pre-grant, the UE may assume the indicated timing to begin preparing for the uplink burst.

[0101] Figure 3 An example of a CoT configuration 300 that supports receiver-side eCCA for unlicensed bands is shown according to aspects of the present disclosure. In some examples, the CoT configuration 300 can implement aspects of the wireless communication system 100 and / or the CoT configuration 200. Aspects of the CoT configuration 300 can be implemented by a base station and / or a UE, which can be examples of corresponding devices described herein. In general, the CoT configuration 300 shows an example CoT that includes a mix of both uplink bursts and downlink bursts (e.g., both uplink transmissions and downlink data transmissions) being performed.

[0102] For example, the base station may perform an eCCA procedure 305 (e.g., a full or CAT-4 LBT / CCA procedure). If the eCCA procedure 305 is successful, the base station may send a grant 310 to the UE. For example, the grant 310 may include an uplink grant for the UE to send an uplink data transmission to the base station and / or a downlink grant (e.g., a pre-grant) indicating scheduling of downlink data transmission for the UE. In some aspects, the grant 310 may indicate timing parameters for the eCCA procedure 305 performed by the base station and / or for the eCCA procedure 315 to be performed by the UE. In some aspects, the grant 310 may indicate CoT.

[0103] Upon receiving the grant 310, the UE may perform an eCCA procedure 315 (e.g., a full or CAT-4 LBT / CCA procedure). If the eCCA procedure 315 is successful, the UE may perform an uplink data transmission 320 to the base station. In some aspects, the UE may multiplex feedback information 325 for the grant 310 with the uplink data transmission 320. Upon receiving the uplink data transmission 320 with the multiplexed feedback information 325 for the grant 310, the base station may perform a CCA procedure 330 (e.g., a one-time or CAT-2 LBT / CCA procedure). If the CCA procedure 330 is successful, the base station may send a downlink data transmission 335 to the UE. Upon successfully receiving and decoding the downlink data transmission 335, the UE may perform a CCA procedure 340 (e.g., a one-time or CAT-2 LBT / CCA procedure). If the CCA procedure 340 is successful, the UE may send a feedback information transmission 345 for the downlink data transmission 335. The feedback information transmission 345 may be an A / N feedback information transmission used to confirm that the UE was able to successfully receive and decode the downlink data transmission 335 .

[0104] Thus, the CoT configuration 300 includes both a base station and a UE that perform an eCCA process. The location (e.g., time) of the eCCA process at the UE may be flexible, but may be performed prior to downlink data transmission 335. In some aspects, the location of the eCCA process at the UE may be the result of a scheduler decision. Feedback information 325 for grant 310 may be piggybacked (e.g., multiplexed) with uplink data transmission 320 (e.g., piggybacked uplink control information (UCI)). As shown in the CoT configuration 300, two eCCA processes are performed. In some aspects, the location (e.g., time) of performing each eCCA process may be flexible, but may include performing the eCCA process prior to the corresponding uplink data transmission 320 and / or downlink data transmission 335.

[0105] Figure 4 An example of a process 400 for supporting receiver-side eCCA for unlicensed bands is shown according to aspects of the present disclosure. In some examples, the process 400 can implement aspects of the wireless communication system 100 and / or the CoT configurations 200 and / or 300. Aspects of the process 400 can be implemented by a first wireless device 405 and / or a second wireless device 410, which can be examples of corresponding devices described herein. In general, the first wireless device 405 can be considered a receiving device, and the second wireless device 410 can be considered a transmitting device.

[0106] At 415, the second wireless device 410 may perform a short CCA process (e.g., a first CCA process from the perspective of the second wireless device 410). The short CCA process may be a CAT-2 or a one-time LBT / CCA process. The short CCA process may be an energy detection based CCA process in which the second wireless device 410 monitors a channel to detect energy. If the second wireless device 410 detects energy below a threshold level, the short CCA process may be successful, but if the second wireless device 410 detects energy at or above a threshold level on the channel, the short CCA process may not be successful. In some aspects, the channel may be associated with an unlicensed radio frequency spectrum band.

[0107] At 420, the second wireless device 410 may send (and the first wireless device 405 may receive) a CCA trigger associated with a data transmission by the second wireless device 410. The CCA trigger may be a grant or pre-grant to schedule a data transmission for the first wireless device 405. The CCA trigger may be sent on a control channel (e.g., PDCCH / PUCCH). The CCA trigger may convey an indication of a duration for a long CCA procedure (e.g., an eCCA procedure) to be performed by the first wireless device 405. For example, the CCA trigger may explicitly convey an indication of the duration, and / or the indication of the duration may be implicitly conveyed by using a specific resource configuration for the CCA trigger and / or for the first wireless device 405 to send feedback information for the CCA trigger. In some aspects, the CCA trigger may be sent based on the success of the short CCA procedure performed at 415. In some aspects, the CCA trigger may carry or otherwise convey an indication of the CoT.

[0108] At 425, the first wireless device 405 may perform a long CCA procedure (e.g., an eCCA or a CAT-4 LBT / CCA procedure). The duration for the long CCA procedure may be based on an indication communicated in a CCA trigger and / or an associated or linked resource configuration. The long CCA procedure may be an energy detection based CCA procedure, in which the first wireless device 405 monitors a channel to detect energy. If the energy detected on the channel is below a threshold level, the long CCA procedure may be considered successful, but if the energy detected on the channel is at or above a threshold level, the long CCA procedure may be considered unsuccessful.

[0109] If the long CCA process is successful, the first wireless device 405 may send (and the second wireless device 410 may receive) feedback information for the CCA trigger at 430. For example, the feedback information may include A / N information for the CCA trigger to confirm that the first wireless device 405 was able to successfully receive and decode the CCA trigger.

[0110] In some aspects, the first wireless device 405 may determine that it has data for transmission to the second wireless device 410. Therefore, the first wireless device 405 may multiplex its data with the feedback information for the CCA trigger in the same transmission burst to the second wireless device 410.

[0111] At 435, the second wireless device 410 may perform a short CCA procedure (e.g., CAT-2 or a one-time LBT / CCA procedure). The short CCA procedure may be a CAT-2 or a one-time LBT / CCA procedure. The short CCA procedure may be an energy detection based CCA procedure, in which the second wireless device 410 monitors the channel to detect energy. If the second wireless device 410 detects energy below a threshold level, the short CCA procedure may be successful, but if the second wireless device 410 detects energy on the channel at or above a threshold level, the short CCA procedure may not be successful.

[0112] In some aspects, the second wireless device 410 may determine that the interval period between receiving feedback information for the CCA trigger and sending the data transmission meets the threshold. Therefore, the short CCA process performed at 435 may be performed based on the interval period meeting the threshold.

[0113] If the short CCA procedure is successful, then at 440, the second wireless device 410 may send (and the first wireless device 405 may receive) a data transmission. The data transmission may be uplink data and / or downlink data. The data transmission may be sent on a data channel such as PDSCH / PUSCH.

[0114] At 445, the second wireless device 410 may perform a short CCA procedure (e.g., CAT-2 or a one-time LBT / CCA procedure). The short CCA procedure may be a CAT-2 or a one-time LBT / CCA procedure. The short CCA procedure may be an energy detection based CCA procedure, in which the second wireless device 410 monitors the channel to detect energy. If the second wireless device 410 detects energy below a threshold level, the short CCA procedure may succeed, but if the second wireless device 410 detects energy on the channel at or above a threshold level, the short CCA procedure may not succeed.

[0115] If the short CCA procedure is successful, the first wireless device 405 may send (and the second wireless device 410 may receive) feedback information for the data transmission at 450. For example, the feedback information may include A / N information for the data transmission to confirm that the first wireless device 405 was able to successfully receive and decode the data transmission.

[0116] In some aspects, the first wireless device 405 may determine that an interval period between receiving a data transmission and sending feedback information for the data transmission satisfies a threshold. Thus, the short CCA procedure performed at 445 may be performed based on the interval period satisfying the threshold.

[0117] Figure 5 A block diagram 500 of a device 505 supporting receiver-side eCCA for unlicensed bands is shown according to aspects of the present disclosure. The device 505 may be an example of aspects of a UE 115 or a base station 105 as described herein. The device 505 may include a receiver 510, a communication manager 515, and a transmitter 520. The device 505 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0118] The receiver 510 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 receiver-side eCCA for unlicensed bands, etc.). The information may be passed to other components of the device 505. The receiver 510 may be a reference Figure 8 and Fig. 9 Examples of aspects of the described transceiver 820 or 920. The receiver 510 may utilize a single antenna or a group of antennas.

[0119] The communication manager 515 can receive a CCA trigger from a second wireless device at a first wireless device, the CCA trigger being associated with a data transmission performed by the second wireless device, send feedback information for the CCA trigger based on a result of a first CCA process, receive data transmission based on the feedback information for the first CCA process, and send feedback information for the data transmission based on a result of a second CCA process, wherein the first CCA process has a first duration that is longer than a second duration for the second CCA process.

[0120] The communication manager 515 may also send a CCA trigger to the first wireless device based on a result of the first CCA process, the CCA trigger being associated with a data transmission by the second wireless device, receive feedback information for the CCA trigger from the first wireless device, and send a data transmission to the first wireless device based on a result of the second CCA process and in response to the feedback information for the CCA trigger, and receive feedback information for the data transmission from the first wireless device. The communication manager 515 may be an example of aspects of the communication manager 810 or 910 as described herein.

[0121] The communication manager 515 or its subcomponents may be implemented in hardware, in code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communication manager 515 or its subcomponents may be performed by a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic devices, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

[0122] The communication manager 515 or its subcomponents can be physically distributed in various locations, including being distributed so that parts of the functions are implemented by one or more physical components at different physical locations. In some examples, according to various aspects of the present disclosure, the communication manager 515 or its subcomponents can be separate and distinct components. In some examples, according to various aspects of the present disclosure, the communication manager 515 or its subcomponents can be combined with one or more other hardware components (including but not limited to input / output (I / O) components, transceivers, network servers, another computing device, one or more other components described in the present disclosure, or combinations thereof).

[0123] The transmitter 520 may transmit signals generated by other components of the device 505. In some examples, the transmitter 520 may be co-located with the receiver 510 in a transceiver module. For example, the transmitter 520 may be a reference Figure 8 and Fig. 9 Examples of aspects of the described transceiver 820 or 920. The transmitter 520 may utilize a single antenna or a group of antennas.

[0124] Figure 6 A block diagram 600 of a device 605 supporting receiver-side eCCA for unlicensed bands is shown according to aspects of the present disclosure. The device 605 may be an example of aspects of the device 505, UE 115, or base station 105 as described herein. The device 605 may include a receiver 610, a communication manager 615, and a transmitter 640. The device 605 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0125] The receiver 610 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 receiver-side eCCA for unlicensed bands, etc.). The information may be passed to other components of the device 605. The receiver 610 may be as described with reference to Figure 8 and Fig. 9Examples of aspects of the described transceiver 820 or 920. The receiver 610 may utilize a single antenna or a group of antennas.

[0126] The communication manager 615 may be an example of aspects of the communication manager 515 as described herein. The communication manager 615 may include a CCA trigger manager 620, a CCA trigger A / N manager 625, a data transfer manager 630, and a data transfer A / N manager 635. The communication manager 615 may be an example of aspects of the communication manager 810 or 910 as described herein.

[0127] The CCA trigger manager 620 may receive, at the first wireless device, a CCA trigger from a second wireless device, the CCA trigger being associated with a data transmission by the second wireless device.

[0128] The CCA trigger A / N manager 625 may send feedback information for the CCA trigger based on the result of the first CCA process.

[0129] The data transmission manager 630 may receive the data transmission based on the feedback information for the first CCA process.

[0130] The data transmission A / N manager 635 may send feedback information for the data transmission based on a result of the second CCA process, wherein the first CCA process has a first duration that is longer than a second duration for the second CCA process.

[0131] The CCA trigger manager 620 may send a CCA trigger to the first wireless device based on a result of the first CCA process, the CCA trigger being associated with a data transmission by the second wireless device.

[0132] The CCA trigger A / N manager 625 may receive feedback information for the CCA trigger from the first wireless device.

[0133] The data transmission manager 630 may send a data transmission to the first wireless device based on the result of the second CCA process and in response to the feedback information for the CCA trigger.

[0134] The data transmission A / N manager 635 may receive feedback information for the data transmission from the first wireless device.

[0135] The transmitter 640 can transmit signals generated by other components of the device 605. In some examples, the transmitter 640 can be co-located with the receiver 610 in a transceiver module. For example, the transmitter 640 can be as described in reference Figure 8 and Fig. 9 Examples of aspects of the described transceiver 820 or 920. The transmitter 640 may utilize a single antenna or a group of antennas.

[0136] Figure 7 A block diagram 700 of a communication manager 705 supporting receiver-side eCCA for unlicensed bands is shown according to aspects of the present disclosure. The communication manager 705 may be an example of aspects of the communication manager 515, the communication manager 615, or the communication manager 810 described herein. The communication manager 705 may include a CCA trigger manager 710, a CCA trigger A / N manager 715, a data transmission manager 720, a data transmission A / N manager 725, a CCA process manager 730, a UL / DL multiplexing manager 735, a channel occupancy time manager 740, a CCA duration manager 745, a resource allocation manager 750, and an interference level manager 755. Each of these modules may communicate directly or indirectly with each other (e.g., via one or more buses).

[0137] The CCA trigger manager 710 may receive a CCA trigger at a first wireless device from a second wireless device, the CCA trigger being associated with a data transmission by the second wireless device. In some examples, the CCA trigger manager 710 may send a CCA trigger to the first wireless device based on a result of the first CCA process, the CCA trigger being associated with a data transmission by the second wireless device.

[0138] The CCA trigger A / N manager 715 may send feedback information for the CCA trigger based on the result of the first CCA process. In some examples, the CCA trigger A / N manager 715 may receive feedback information for the CCA trigger from the first wireless device.

[0139] The data transmission manager 720 may receive the data transmission based on the feedback information for the first CCA process. In some examples, the data transmission manager 720 may send the data transmission to the first wireless device based on the result of the second CCA process and in response to the feedback information for the CCA trigger.

[0140] The data transmission A / N manager 725 may send feedback information for the data transmission based on the result of the second CCA process, wherein the first CCA process has a first duration that is longer than a second duration for the second CCA process. In some examples, the data transmission A / N manager 725 may receive feedback information for the data transmission from the first wireless device.

[0141] If the first CCA process is successful, the CCA process manager 730 may send feedback information. In some examples, the CCA process manager 730 may determine that an interval period between receiving a data transmission and sending feedback information for the data transmission satisfies a threshold, wherein the second channel assessment process is performed based on the interval period satisfying the threshold. In some examples, if the first CCA process is successful, the CCA process manager 730 may send a CCA trigger to trigger data transmission to the first wireless device.

[0142] The UL / DL multiplexing manager 735 may determine that the first wireless device has data for transmission to the second wireless device. In some examples, the UL / DL multiplexing manager 735 may multiplex the data with the feedback information for the first CCA trigger in the same transmission burst to the second wireless device. In some examples, the UL / DL multiplexing manager 735 may determine that the first wireless device has data for transmission to the second wireless device. In some examples, the UL / DL multiplexing manager 735 may receive the data multiplexed with the feedback information for the first CCA trigger in the same transmission burst from the first wireless device. In some examples, the UL / DL multiplexing manager 735 may select a first duration for the first CCA process based on the data, wherein the first duration is longer than a second duration for the second CCA process.

[0143] The channel occupancy time manager 740 may determine the channel occupancy time for data transmission based on the CCA trigger. In some examples, the channel occupancy time manager 740 may determine the channel occupancy time for data transmission based on the first CCA procedure.

[0144] The CCA duration manager 745 may determine the interval duration between receiving a data transmission and sending feedback information for the data transmission based on the CCA trigger. In some examples, the CCA duration manager 745 may select a second duration for a second CCA process based on the interval duration. In some examples, the CCA duration manager 745 may determine a first duration for a first CCA process based on the CCA trigger. In some examples, the CCA duration manager 745 may identify a duration for a third CCA process to be performed by the first wireless device before sending feedback information for the CCA trigger.

[0145] In some examples, the CCA duration manager 745 may select a resource allocation for the first wireless device for sending feedback information for the CCA trigger based on the duration for the third CCA process. In some examples, the CCA duration manager 745 may send the resource allocation to the first wireless device. In some examples, the CCA duration manager 745 may determine that an interval period between receiving the feedback information for the CCA trigger and sending the data transmission satisfies a threshold, wherein the second CCA process is performed based on the interval period satisfying the threshold.

[0146] Resource allocation manager 750 may receive a resource allocation for sending feedback information for a CCA trigger. In some examples, resource allocation manager 750 may determine a first duration of a first CCA procedure based on the resource allocation for sending feedback information for a CCA trigger.

[0147] The interference level manager 755 may determine that an interference level for a channel used to communicate with the first wireless device has a threshold rate of change, wherein the second CCA process is performed based on the threshold rate of change.

[0148] Figure 8 A schematic diagram of a system 800 including a device 805 is shown according to aspects of the present disclosure, and the device 805 supports receiver-side eCCA for unlicensed bands. The device 805 can be an example of a device 505, a device 605, or a UE 115 as described herein, or include a component of the device 505, the device 605, or the UE 115. The device 805 may include components for two-way voice and data communications, including components for sending and receiving communications, including a communication manager 810, a transceiver 820, an antenna 825, a memory 830, a processor 840, and an I / O controller 850. These components can be in electrical communication via one or more buses (e.g., a bus 855).

[0149] The communication manager 810 may receive, at the first wireless device, a CCA trigger from the second wireless device, the CCA trigger being associated with a data transmission by the second wireless device, send feedback information for the CCA trigger based on a result of a first CCA process, receive the data transmission based on the feedback information for the first CCA process, and send feedback information for the data transmission based on a result of a second CCA process, wherein the first CCA process has a first duration that is longer than a second duration for the second CCA process. The communication manager 810 may also send a CCA trigger to the first wireless device based on a result of the first CCA process, the CCA trigger being associated with a data transmission by the second wireless device, receive feedback information for the CCA trigger from the first wireless device, and send the data transmission to the first wireless device based on a result of the second CCA process and in response to the feedback information for the CCA trigger, and receive feedback information for the data transmission from the first wireless device.

[0150] The transceiver 820 may communicate bidirectionally via one or more antennas, wired links, or wireless links, as described above. For example, the transceiver 820 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The transceiver 820 may also include a modem to modulate packets and provide the modulated packets to an antenna for transmission, and demodulate packets received from an antenna.

[0151] In some cases, a wireless device may include a single antenna 825. However, in some cases, a device may have more than one antenna 825, which may be capable of sending or receiving multiple wireless transmissions simultaneously.

[0152] The memory 830 may include random access memory (RAM), read-only memory (ROM), or a combination thereof. The memory 830 may store computer readable code 835 including instructions that, when executed by a processor (e.g., processor 840), cause the device to perform various functions described herein. In some cases, the memory 830 may include, among other things, a basic input / output system (BIOS) that may control basic hardware or software operations, such as interaction with peripheral components or devices.

[0153] The processor 840 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, the processor 840 may be configured to operate a memory array using a memory controller. In other cases, the memory controller may be integrated into the processor 840. The processor 840 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 830) to cause the device 805 to perform various functions (e.g., functions or tasks for supporting receiver-side eCCA for unlicensed bands).

[0154] I / O controller 850 can manage input and output signals for device 805. I / O controller 850 can also manage peripheral devices that are not integrated into device 805. In some cases, I / O controller 850 can represent a physical connection or port to an external peripheral device. In some cases, I / O controller 850 can utilize a computer such as a 805. In some cases, the I / O controller 850 may be implemented as part of a processor. In some cases, a user may interact with the device 805 via the I / O controller 850 or via hardware components controlled by the I / O controller 850.

[0155] The code 835 may include instructions for implementing various aspects of the present disclosure, including instructions for supporting wireless communications. The code 835 may be stored in a non-transitory computer-readable medium such as a system memory or other type of memory. In some cases, the code 835 may not be executed directly by the processor 840, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein.

[0156] Fig. 9A schematic diagram of a system 900 including a device 905 is shown according to aspects of the present disclosure, and the device 905 supports receiver-side eCCA for unlicensed bands. The device 905 can be an example of a device 505, a device 605, or a base station 105 as described herein, or include a component of the device 505, the device 605, or the base station 105. The device 905 may include components for two-way voice and data communications, including components for sending and receiving communications, including a communication manager 910, a network communication manager 915, a transceiver 920, an antenna 925, a memory 930, a processor 940, and an inter-station communication manager 945. These components can be in electrical communication via one or more buses (e.g., a bus 955).

[0157] The communication manager 910 may receive, at the first wireless device, a CCA trigger from the second wireless device, the CCA trigger being associated with a data transmission by the second wireless device, send feedback information for the CCA trigger based on a result of a first CCA process, receive the data transmission based on the feedback information for the first CCA process, and send feedback information for the data transmission based on a result of a second CCA process, wherein the first CCA process has a first duration that is longer than a second duration for the second CCA process. The communication manager 910 may also send a CCA trigger to the first wireless device based on a result of the first CCA process, the CCA trigger being associated with a data transmission by the second wireless device, receive feedback information for the CCA trigger from the first wireless device, and send the data transmission to the first wireless device based on a result of the second CCA process and in response to the feedback information for the CCA trigger, and receive feedback information for the data transmission from the first wireless device.

[0158] The network communications manager 915 may manage communications with the core network (eg, via one or more wired backhaul links). For example, the network communications manager 915 may manage the delivery of data communications for client devices, such as one or more UEs 115.

[0159] The transceiver 920 may communicate bidirectionally via one or more antennas, wired links, or wireless links, as described above. For example, the transceiver 920 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The transceiver 920 may also include a modem to modulate packets, and provide the modulated packets to an antenna for transmission, and demodulate packets received from an antenna.

[0160] In some cases, a wireless device may include a single antenna 925. However, in some cases, a device may have more than one antenna 925, which may be capable of sending or receiving multiple wireless transmissions simultaneously.

[0161] The memory 930 may include RAM, ROM, or a combination thereof. The memory 930 may store computer readable code 935 including instructions that, when executed by a processor (e.g., processor 940), cause the device to perform various functions described herein. In some cases, the memory 930 may include, among other things, a BIOS that may control basic hardware or software operations such as interactions with peripheral components or devices.

[0162] The processor 940 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, the processor 940 may be configured to operate a memory array using a memory controller. In other cases, the memory controller may be integrated into the processor 940. The processor 940 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 930) to cause the device 905 to perform various functions (e.g., functions or tasks for supporting receiver-side eCCA for unlicensed bands).

[0163] The inter-station communication manager 945 may manage communications with other base stations 105 and may include a controller or scheduler for controlling communications with UE 115 in cooperation with other base stations 105. For example, the inter-station communication manager 945 may coordinate scheduling of transmissions to UE 115 for various interference mitigation techniques such as beamforming or joint transmission. In some examples, the inter-station communication manager 945 may provide an X2 interface in an LTE / LTE-A wireless communication network technology to provide communications between base stations 105.

[0164] The code 935 may include instructions for implementing various aspects of the present disclosure, including instructions for supporting wireless communications. The code 935 may be stored in a non-transitory computer-readable medium such as a system memory or other type of memory. In some cases, the code 935 may not be executed directly by the processor 940, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein.

[0165] Fig.10 A flow chart of a method 1000 for supporting receiver-side eCCA for unlicensed bands is shown according to aspects of the present disclosure. The operations of the method 1000 may be implemented by a UE 115 or a base station 105 or components thereof as described herein. For example, the operations of the method 1000 may be implemented by a UE 115 or a base station 105 or components thereof as described herein. Figures 5 to 9In some examples, the UE or base station may execute an instruction set to control the functional elements of the UE or base station to perform the functions described below. Additionally or alternatively, the UE or base station may use dedicated hardware to perform various aspects of the functions described below.

[0166] At 1005, the UE or base station may receive a CCA trigger at a first wireless device from a second wireless device, the CCA trigger being associated with a data transmission by the second wireless device. The operations of 1005 may be performed according to the methods described herein. In some examples, aspects of the operations of 1005 may be performed as described with reference to Figures 5 to 9 The described CCA trigger manager is executed.

[0167] At 1010, the UE or base station may send feedback information for a CCA trigger based at least in part on the result of the first CCA process. The operations of 1010 may be performed according to the methods described herein. In some examples, aspects of the operations of 1010 may be as described with reference to Figures 5 to 9 The described CCA triggers the A / N manager to execute.

[0168] At 1015, the UE or base station may receive data transmission based at least in part on the feedback information for the first CCA process. The operations of 1015 may be performed according to the methods described herein. In some examples, aspects of the operations of 1015 may be performed as described with reference to Figures 5 to 9 The data transfer manager described is performed.

[0169] At 1020, the UE or base station may send feedback information for data transmission based at least in part on the result of the second CCA process, wherein the first CCA process has a first duration that is longer than a second duration for the second CCA process. The operations of 1020 may be performed according to the methods described herein. In some examples, aspects of the operations of 1020 may be as described with reference to Figures 5 to 9 The described data transfer A / N manager is performed.

[0170] Fig.11 A flow chart of a method 1100 for supporting receiver-side eCCA for unlicensed bands is shown according to aspects of the present disclosure. The operations of the method 1100 may be implemented by a UE 115 or a base station 105 or components thereof as described herein. For example, the operations of the method 1100 may be implemented by a UE 115 or a base station 105 or components thereof as described herein. Figures 5 to 9 In some examples, the UE or base station may execute an instruction set to control the functional elements of the UE or base station to perform the functions described below. Additionally or alternatively, the UE or base station may use dedicated hardware to perform various aspects of the functions described below.

[0171] At 1105, the UE or base station may receive a CCA trigger at the first wireless device from the second wireless device, the CCA trigger being associated with a data transmission by the second wireless device. The operations of 1105 may be performed according to the methods described herein. In some examples, aspects of the operations of 1105 may be performed as described with reference to Figures 5 to 9 The described CCA trigger manager is executed.

[0172] At 1110, the UE or base station may determine that the first wireless device has data for transmission to the second wireless device. The operations of 1110 may be performed according to the methods described herein. In some examples, aspects of the operations of 1110 may be performed as described with reference to Figures 5 to 9 The described UL / DL multiplexing manager is performed.

[0173] At 1115, the UE or base station may multiplex the data with the feedback information for the first CCA trigger in the same transmission burst to the second wireless device. The operations of 1115 may be performed according to the methods described herein. In some examples, aspects of the operations of 1115 may be as described with reference to Figures 5 to 9 The described UL / DL multiplexing manager is performed.

[0174] At 1120, the UE or base station may send feedback information for a CCA trigger based at least in part on the result of the first CCA process. The operations of 1120 may be performed according to the methods described herein. In some examples, aspects of the operations of 1120 may be as described with reference to Figures 5 to 9 The described CCA triggers the A / N manager to execute.

[0175] At 1125, the UE or base station may receive data transmission based at least in part on the feedback information for the first CCA process. The operations of 1125 may be performed according to the methods described herein. In some examples, aspects of the operations of 1125 may be performed as described with reference to Figures 5 to 9 The data transfer manager described is performed.

[0176] At 1130, the UE or base station may send feedback information for data transmission based at least in part on the result of the second CCA process, wherein the first CCA process has a first duration that is longer than a second duration for the second CCA process. The operations of 1130 may be performed according to the methods described herein. In some examples, aspects of the operations of 1130 may be performed as described with reference to Figures 5 to 9 The described data transfer A / N manager is performed.

[0177] Fig.12A flow chart of a method 1200 for supporting receiver-side eCCA for unlicensed bands is shown according to aspects of the present disclosure. The operations of the method 1200 may be implemented by a UE 115 or a base station 105 or components thereof as described herein. For example, the operations of the method 1200 may be implemented by a UE 115 or a base station 105 or components thereof as described herein. Figures 5 to 9 In some examples, the UE or base station may execute an instruction set to control the functional elements of the UE or base station to perform the functions described below. Additionally or alternatively, the UE or base station may use dedicated hardware to perform various aspects of the functions described below.

[0178] At 1205, the UE or base station may receive a CCA trigger at the first wireless device from the second wireless device, the CCA trigger being associated with a data transmission by the second wireless device. The operations of 1205 may be performed according to the methods described herein. In some examples, aspects of the operations of 1205 may be performed as described with reference to Figures 5 to 9 The described CCA trigger manager is executed.

[0179] At 1210, the UE or base station may send feedback information for a CCA trigger based at least in part on the result of the first CCA process. The operations of 1210 may be performed according to the methods described herein. In some examples, aspects of the operations of 1210 may be as described with reference to Figures 5 to 9 The described CCA triggers the A / N manager to execute.

[0180] At 1215, the UE or base station may receive data transmission based at least in part on the feedback information for the first CCA process. The operations of 1215 may be performed according to the methods described herein. In some examples, aspects of the operations of 1215 may be performed as described with reference to Figures 5 to 9 The data transfer manager described is performed.

[0181] At 1220, the UE or base station may determine, based at least in part on the CCA trigger, a duration of an interval between receiving a data transmission and sending feedback information for the data transmission. The operations of 1220 may be performed according to the methods described herein. In some examples, aspects of the operations of 1220 may be performed as described with reference to Figures 5 to 9 The described CCA duration manager is executed.

[0182] At 1225, the UE or base station may select a second duration for the second CCA process based at least in part on the interval duration. The operations of 1225 may be performed according to the methods described herein. In some examples, aspects of the operations of 1225 may be as described with reference to Figures 5 to 9 The described CCA duration manager is executed.

[0183] At 1230, the UE or base station may send feedback information for data transmission based at least in part on the result of the second CCA process, wherein the first CCA process has a first duration that is longer than a second duration for the second CCA process. The operations of 1230 may be performed according to the methods described herein. In some examples, aspects of the operations of 1230 may be performed as described with reference to Figures 5 to 9 The described data transfer A / N manager is performed.

[0184] Fig.13 A flow chart of a method 1300 for supporting receiver-side eCCA for unlicensed bands is shown according to aspects of the present disclosure. The operations of the method 1300 may be implemented by a UE 115 or a base station 105 or components thereof as described herein. For example, the operations of the method 1300 may be implemented by a UE 115 or a base station 105 or components thereof as described herein. Figures 5 to 9 In some examples, the UE or base station may execute an instruction set to control the functional elements of the UE or base station to perform the functions described below. Additionally or alternatively, the UE or base station may use dedicated hardware to perform various aspects of the functions described below.

[0185] At 1305, the UE or base station may send a CCA trigger to the first wireless device based at least in part on the result of the first CCA process, the CCA trigger being associated with a data transmission by the second wireless device. The operations of 1305 may be performed according to the methods described herein. In some examples, aspects of the operations of 1305 may be performed as described with reference to Figures 5 to 9 The described CCA trigger manager is executed.

[0186] At 1310, the UE or base station may receive feedback information for CCA triggering from the first wireless device. The operations of 1310 may be performed according to the methods described herein. In some examples, aspects of the operations of 1310 may be performed as described with reference to Figures 5 to 9 The described CCA triggers the A / N manager to execute.

[0187] At 1315, the UE or base station may send a data transmission to the first wireless device based at least in part on the result of the second CCA process and in response to the feedback information for the CCA trigger. The operations of 1315 may be performed according to the methods described herein. In some examples, aspects of the operations of 1315 may be performed as described with reference to Figures 5 to 9 The data transfer manager described is performed.

[0188] At 1320, the UE or base station may receive feedback information for data transmission from the first wireless device. The operations of 1320 may be performed according to the methods described herein. In some examples, aspects of the operations of 1320 may be performed as described with reference to Figures 5 to 9 The described data transfer A / N manager is performed.

[0189] Fig.14 A flow chart of a method 1400 for supporting receiver-side eCCA for unlicensed bands is shown according to aspects of the present disclosure. The operations of the method 1400 may be implemented by a UE 115 or a base station 105 or components thereof as described herein. For example, the operations of the method 1400 may be implemented by a UE 115 or a base station 105 or components thereof as described herein. Figures 5 to 9 In some examples, the UE or base station may execute an instruction set to control the functional elements of the UE or base station to perform the functions described below. Additionally or alternatively, the UE or base station may use dedicated hardware to perform various aspects of the functions described below.

[0190] At 1405, the UE or base station may send a CCA trigger to the first wireless device based at least in part on the result of the first CCA process, the CCA trigger being associated with a data transmission by the second wireless device. The operations of 1405 may be performed according to the methods described herein. In some examples, aspects of the operations of 1405 may be performed as described with reference to Figures 5 to 9 The described CCA trigger manager is executed.

[0191] At 1410, the UE or base station may determine a channel occupancy time for data transmission based at least in part on the first CCA process. The operations of 1410 may be performed according to the methods described herein. In some examples, aspects of the operations of 1410 may be performed as described with reference to Figures 5 to 9 The described channel occupancy time manager is implemented.

[0192] At 1415, the UE or base station may receive feedback information for CCA triggering from the first wireless device. The operations of 1415 may be performed according to the methods described herein. In some examples, aspects of the operations of 1415 may be performed as described with reference to Figures 5 to 9 The described CCA triggers the A / N manager to execute.

[0193] At 1420, the UE or base station may send a data transmission to the first wireless device based at least in part on the result of the second CCA process and in response to the feedback information for the CCA trigger. The operations of 1420 may be performed according to the methods described herein. In some examples, aspects of the operations of 1420 may be performed as described with reference to Figures 5 to 9 The data transfer manager described is performed.

[0194] At 1425, the UE or base station may receive feedback information for the data transmission from the first wireless device. The operations of 1425 may be performed according to the methods described herein. In some examples, aspects of the operations of 1425 may be performed as described with reference to Figures 5 to 9 The described data transfer A / N manager is performed.

[0195] It should be noted that the methods described herein describe possible implementations, and that the operations and steps may be rearranged or otherwise modified, and that other implementations are possible. Further, aspects of two or more of the methods may be combined.

[0196] The following provides an overview of various aspects of the present disclosure:

[0197] Aspect 1: A method for wireless communication, comprising: receiving a CCA trigger from a second wireless device at a first wireless device, the CCA trigger being associated with a data transmission performed by the second wireless device; sending feedback information for the CCA trigger based at least in part on a result of a first CCA process; receiving data transmission based at least in part on the feedback information for the first CCA process; and sending feedback information for the data transmission based at least in part on a result of a second CCA process, wherein the first CCA process has a first duration that is longer than a second duration for the second CCA process.

[0198] Aspect 2: The method according to aspect 1, wherein sending feedback information for CCA triggering based at least in part on the result of the first CCA process includes: sending feedback information if the first CCA process is successful.

[0199] Aspect 3: The method according to any one of Aspects 1 to 2 further includes: determining that the first wireless device has data for transmission to the second wireless device; and multiplexing the data with feedback information triggered for the first CCA in the same transmission burst to the second wireless device.

[0200] Aspect 4: The method according to any one of aspects 1 to 3 further includes: determining a channel occupancy time for data transmission based at least in part on a CCA trigger.

[0201] Aspect 5: The method according to any one of Aspects 1 to 4 further includes: determining the duration of an interval between receiving a data transmission and sending feedback information for the data transmission based at least in part on a CCA trigger; and selecting a second duration for a second CCA process based at least in part on the interval duration.

[0202] Aspect 6: The method according to any one of Aspects 1 to 5 further includes: determining a first duration for a first CCA process based on a CCA trigger.

[0203] Aspect 7: The method according to any one of Aspects 1 to 6 further includes: receiving resource allocation for sending feedback information for CCA triggering; and determining a first duration of the first CCA process based on the resource allocation for sending feedback information for CCA triggering.

[0204] Aspect 8: The method according to any one of Aspects 1 to 7 further includes: determining that an interval period between receiving data transmission and sending feedback information for the data transmission satisfies a threshold, wherein the second channel assessment process is performed at least in part based on the interval period satisfying the threshold.

[0205] Aspect 9: A method for wireless communication: sending a CCA trigger to a first wireless device based at least in part on a result of a first CCA process, the CCA trigger being associated with a data transmission performed by a second wireless device; receiving feedback information for the CCA trigger from the first wireless device; sending data transmission to the first wireless device based at least in part on a result of a second CCA process and in response to the feedback information for the CCA trigger; and receiving feedback information for the data transmission from the first wireless device.

[0206] Aspect 10: The method according to aspect 9, wherein sending the CCA trigger includes: if the first CCA process is successful, sending the CCA trigger to trigger data transmission to the first wireless device.

[0207] Aspect 11: The method according to any one of Aspects 9 to 10 further includes: determining that the first wireless device has data for transmission to the second wireless device; and receiving data multiplexed with feedback information triggered for the first CCA in the same transmission burst from the first wireless device.

[0208] Aspect 12: The method according to aspect 11 also includes: selecting a first duration for the first CCA process based at least in part on the data, wherein the first duration is longer than a second duration for the second CCA process.

[0209] Aspect 13: The method according to any one of aspects 9 to 12 further includes: determining a channel occupancy time for data transmission based at least in part on the first CCA process.

[0210] Aspect 14: The method according to any one of Aspects 9 to 13 further includes: identifying the duration of a third CCA process for the first wireless device to perform before sending feedback information triggered by the CCA; selecting a resource allocation for the first wireless device for sending feedback information triggered by the CCA based at least in part on the duration of the third CCA process; and sending the resource allocation to the first wireless device.

[0211] Aspect 15: The method according to any one of Aspects 9 to 14 further includes: determining that an interference level for a channel used to communicate with the first wireless device has a threshold change rate, wherein the second CCA process is performed at least in part based on the threshold change rate.

[0212] Aspect 16: The method according to any one of Aspects 9 to 15 further includes: determining that an interval period between receiving feedback information triggered for CCA and sending data transmission meets a threshold, wherein the second CCA process is performed at least in part based on the interval period meeting the threshold.

[0213] Aspect 17: An apparatus for wireless communication, comprising a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method of any one of Aspects 1 to 8.

[0214] Aspect 18: An apparatus for wireless communication, comprising at least one unit for executing the method according to any one of Aspects 1 to 8.

[0215] Aspect 19: A non-transitory computer-readable medium storing a code for wireless communication, the code comprising instructions executable by a processor to perform the method of any one of aspects 1 to 8.

[0216] Aspect 20: An apparatus comprising a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method of any one of aspects 9 to 16.

[0217] Aspect 21: An apparatus comprising at least one unit for executing the method of any one of Aspects 9 to 16.

[0218] Aspect 22: A non-transitory computer-readable medium storing code, the code comprising instructions executable by a processor to perform the method of any one of Aspects 9 to 16.

[0219] Although aspects of LTE, LTE-A, LTE-APro, or NR systems may be described for example purposes, and LTE, LTE-A, LTE-APro, or NR terminology may be used in most of the description, the techniques described herein are applicable beyond LTE, LTE-A, LTE-APro, or NR networks. For example, the techniques described may be applicable to various other wireless communication systems, such as Ultra Mobile Broadband (UMB), Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash OFDM, and other systems and radio technologies not explicitly mentioned herein.

[0220] The information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips cited throughout the specification may be represented by voltage, current, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0221] A general purpose processor, DSP, ASIC, CPU, FPGA or other programmable logic device, discrete gate or transistor logic device, discrete hardware components, or any combination thereof designed to perform the functions described herein may be used to implement or perform the various illustrative blocks and components described in conjunction with the disclosure herein. A general purpose processor may be a microprocessor, but in an alternative embodiment the processor may be any 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, a plurality of microprocessors, a combination of one or more microprocessors and a DSP core, or any other such configuration).

[0222] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. When implemented in software executed by a processor, the functions may be stored on a computer-readable medium or transmitted as one or more instructions or codes on a computer-readable medium. Other examples and implementations are within the scope of protection of the present disclosure and the claims thereto. For example, due to the nature of software, the functions described herein may be implemented using software executed by a processor, hardware, firmware, hardware wiring, or any combination of these items. Features used to implement the functions may also be physically distributed at multiple locations, including being distributed so that portions of the functions are implemented at different physical locations.

[0223] Computer-readable media include both non-transitory computer storage media and communication media, and communication media include any medium that facilitates the transmission of computer programs from one place to another.Non-transitory storage media can be any available medium that can be accessed by a general or special computer.For example, but not limited to, non-transitory computer-readable media can include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), flash memory, compact disc (CD) ROM or other optical disc storage, disk storage or other magnetic storage device, or can be used to carry or store the desired program code unit with the form of instruction or data structure and can be accessed by a general or special computer, or a general or special processor Any other non-transitory medium.In addition, any connection can be appropriately referred to as a computer-readable medium.For example, if the software is sent from a website, server or other remote source using coaxial cable, optical fiber cable, twisted pair, digital subscriber line (DSL) or wireless technology such as infrared, radio and microwave, then coaxial cable, optical fiber cable, twisted pair, DSL or wireless technology such as infrared, radio and microwave are included in the definition of computer-readable media. As used herein, disks and optical disks include CDs, laser disks, optical disks, digital versatile disks (DVDs), floppy disks, and Blu-ray disks, where disks typically reproduce data magnetically, while optical disks reproduce data optically with lasers. Combinations of the above should also be included within the scope of protection of computer-readable media.

[0224] As used herein (including in the claims), "or" as used in a list item (e.g., a list item ending with a phrase such as "at least one of" or "one or more of") indicates an inclusive list, so that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). In addition, as used herein, the phrase "based on" should not be interpreted as referring to a closed set of conditions. For example, an exemplary step described as "based on condition A" can be based on both condition A and condition B without departing from the scope of protection of the present disclosure. In other words, as used herein, the phrase "based on" should be interpreted in the same manner as the phrase "based at least in part on."

[0225] In the drawings, similar components or features may have the same reference label. Further, individual components of the same type may be distinguished by following the reference label with a dash and a second label for distinguishing among similar components. If only the first reference label is used in the specification, the description is applicable to any of the similar components having the same first reference label, regardless of the second reference label or other subsequent reference labels.

[0226] The description set forth herein in conjunction with the accompanying drawings describes example configurations, but does not represent all examples that can be implemented, nor does it represent all examples that can be implemented or within the scope of protection of the claims. The term "example" as used herein means "used as an example, instance, or illustration", but does not mean "preferable over other examples" or "more advantageous". For the purpose of providing an understanding of the described techniques, the specific embodiments include specific details. However, these techniques can be practiced without these specific details. In some instances, in order to avoid obscuring the concepts of the described examples, known structures and devices are shown in block diagram form.

[0227] The description herein is provided to enable one of ordinary skill in the art to implement or use the present disclosure. Various modifications to the present disclosure will be apparent to one of ordinary skill in the art, and the general principles defined herein may be applied to other variations without departing from the scope of protection of the present disclosure. Therefore, the present disclosure is not limited to the examples and designs described herein, but is given the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for wireless communication, comprising: receiving, at the first wireless device, a clear channel assessment trigger from a second wireless device based at least in part on a result of the first clear channel assessment process, the clear channel assessment trigger being associated with a data transmission by the second wireless device; Sending feedback information for the clear channel assessment trigger based at least in part on a result of a second clear channel assessment process; receiving the data transmission based at least in part on the feedback information triggered for the clear channel assessment and a result of a third clear channel assessment process; as well as Feedback information for the data transmission is sent based at least in part on a result of a fourth clear channel assessment procedure, wherein the second clear channel assessment procedure has a first duration that is longer than a second duration used for the first, third, or fourth clear channel assessment procedure.

2. The method according to claim 1, wherein: Sending feedback information triggered for the idle channel assessment based at least in part on the result of the second idle channel assessment process includes: If the second idle channel assessment process is successful, the feedback information is sent.

3. The method according to claim 1, further comprising: determining that the first wireless device has data for transmission to the second wireless device; as well as The data is multiplexed with the feedback information triggered for the second clear channel assessment in a same transmission burst to the second wireless device.

4. The method according to claim 1, further comprising: A channel occupancy time for the data transmission is determined based at least in part on the clear channel assessment trigger.

5. The method according to claim 1, further comprising: determining a duration of an interval between receiving the data transmission and sending the feedback information for the data transmission based at least in part on the clear channel assessment trigger; as well as The second duration for the fourth clear channel assessment procedure is selected based at least in part on the interval duration.

6. The method according to claim 1, further comprising: The first duration for the second clear channel assessment process is determined based on the clear channel assessment trigger.

7. The method according to claim 1, further comprising: receiving a resource allocation for sending the feedback information triggered by the idle channel assessment; as well as The first duration of the second clear channel assessment process is determined based on the resource allocation for sending the feedback information for the clear channel assessment trigger.

8. The method according to claim 1, further comprising: Determining that an interval period between receiving the data transmission and sending the feedback information for the data transmission satisfies a threshold, wherein the second clear channel assessment process is performed based at least in part on the interval period satisfying the threshold.

9. A method for wireless communication, comprising: sending a clear channel assessment trigger to the first wireless device based at least in part on a result of the first clear channel assessment process, the clear channel assessment trigger being associated with a data transmission by the second wireless device; receiving feedback information for the clear channel assessment trigger from the first wireless device based at least in part on a result of a second clear channel assessment process; sending the data transmission to the first wireless device based at least in part on a result of a third clear channel assessment process and in response to the feedback information triggered for the clear channel assessment; as well as Feedback information for the data transmission is received from the first wireless device based at least in part on results of a fourth clear channel assessment process, wherein the second clear channel assessment process has a first duration that is longer than a second duration used for the first, third, or fourth clear channel assessment process.

10. The method according to claim 9, wherein: Sending the idle channel assessment trigger includes: If the first clear channel assessment process is successful, the clear channel assessment trigger is sent to trigger the data transmission to the first wireless device.

11. The method according to claim 9, further comprising: determining that the first wireless device has data for transmission to the second wireless device; as well as The data is received multiplexed with the feedback information for the first clear channel assessment trigger in a same transmission burst from the first wireless device.

12. The method according to claim 9, further comprising: A channel occupancy time for the data transmission is determined based at least in part on the first clear channel assessment procedure.

13. The method according to claim 9, further comprising: identifying a duration of the first clear channel assessment process for the first wireless device to perform before sending the feedback information for the clear channel assessment trigger; selecting, based at least in part on the duration for the first clear channel assessment procedure, a resource allocation for the first wireless device for transmitting the feedback information for the clear channel assessment trigger; as well as The resource allocation is sent to the first wireless device.

14. An apparatus for wireless communication, comprising: processor, A memory coupled to the processor, wherein the memory includes instructions executable by the processor to cause the apparatus to: receiving, at the first wireless device, a clear channel assessment trigger from a second wireless device based at least in part on a result of the first clear channel assessment process, the clear channel assessment trigger being associated with a data transmission by the second wireless device; Sending feedback information for the clear channel assessment trigger based at least in part on a result of a second clear channel assessment process; receiving the data transmission based at least in part on the feedback information triggered for the clear channel assessment and a result of a third clear channel assessment process; and Feedback information for the data transmission is sent based at least in part on a result of a fourth clear channel assessment procedure, wherein the second clear channel assessment procedure has a first duration that is longer than a second duration used for the first, third, or fourth clear channel assessment procedure.

15. The device according to claim 14, wherein: The instructions for sending feedback information triggered by the clear channel assessment process based at least in part on the result of the second clear channel assessment process may be executed by the processor to cause the apparatus to: If the second idle channel assessment process is successful, the feedback information is sent.

16. The device according to claim 14, wherein: The instructions may also be executed by the processor to cause the device to perform the following operations: determining that the first wireless device has data for transmission to the second wireless device; and The data is multiplexed with the feedback information triggered for the second clear channel assessment in a same transmission burst to the second wireless device.

17. The device according to claim 14, wherein: The instructions may also be executed by the processor to cause the device to perform the following operations: A channel occupancy time for the data transmission is determined based at least in part on the clear channel assessment trigger.

18. The device according to claim 14, wherein: The instructions may also be executed by the processor to cause the device to perform the following operations: determining a duration of an interval between receiving the data transmission and sending the feedback information for the data transmission based at least in part on the clear channel assessment trigger; as well as The second duration for the fourth clear channel assessment procedure is selected based at least in part on the interval duration.

19. The device according to claim 14, wherein: The instructions may also be executed by the processor to cause the device to perform the following operations: The first duration for the second clear channel assessment process is determined based on the clear channel assessment trigger.

20. The device according to claim 14, wherein: The instructions may also be executed by the processor to cause the device to perform the following operations: receiving a resource allocation for sending the feedback information triggered by the clear channel assessment; and The first duration of the second clear channel assessment process is determined based on the resource allocation for sending the feedback information for the clear channel assessment trigger.

21. The device according to claim 14, wherein: The instructions may also be executed by the processor to cause the device to perform the following operations: Determining that an interval period between receiving the data transmission and sending the feedback information for the data transmission satisfies a threshold, wherein the second clear channel assessment process is performed based at least in part on the interval period satisfying the threshold.

22. An apparatus for wireless communication, comprising: processor, A memory coupled to the processor, wherein the memory includes instructions executable by the processor to cause the apparatus to: sending a clear channel assessment trigger to the first wireless device based at least in part on a result of the first clear channel assessment process, the clear channel assessment trigger being associated with a data transmission by the second wireless device; receiving feedback information for the clear channel assessment trigger from the first wireless device based at least in part on a result of a second clear channel assessment process; sending the data transmission to the first wireless device based at least in part on a result of a third clear channel assessment process and in response to the feedback information triggered for the clear channel assessment; and Feedback information for the data transmission is received from the first wireless device based at least in part on results of a fourth clear channel assessment process, wherein the second clear channel assessment process has a first duration that is longer than a second duration used for the first, third, or fourth clear channel assessment process.

23. The device according to claim 22, wherein: The instructions for sending the clear channel assessment trigger may be executed by the processor to cause the apparatus to perform the following operations: If the first clear channel assessment process is successful, the clear channel assessment trigger is sent to trigger the data transmission to the first wireless device.

24. The device according to claim 22, wherein: The instructions may also be executed by the processor to cause the device to perform the following operations: determining that the first wireless device has data for transmission to the second wireless device; and The data is received multiplexed with the feedback information for the first clear channel assessment trigger in a same transmission burst from the first wireless device.

25. The device according to claim 22, wherein: The instructions may also be executed by the processor to cause the device to perform the following operations: A channel occupancy time for the data transmission is determined based at least in part on the first clear channel assessment procedure.

26. The device according to claim 22, wherein: The instructions may also be executed by the processor to cause the device to perform the following operations: identifying a duration of the first clear channel assessment process for the first wireless device to perform before sending the feedback information for the clear channel assessment trigger; selecting, based at least in part on the duration for the first clear channel assessment procedure, a resource allocation for the first wireless device for transmitting the feedback information for the clear channel assessment trigger; as well as The resource allocation is sent to the first wireless device.

27. The device according to claim 22, wherein: The instructions may also be executed by the processor to cause the device to perform the following operations: Determining an interference level of a channel used for communicating with the first wireless device has a threshold rate of change, wherein the second clear channel assessment process is performed based at least in part on the threshold rate of change.

28. The device according to claim 22, wherein: The instructions may also be executed by the processor to cause the device to perform the following operations: Determining that an interval period between receiving the feedback information triggered for the clear channel assessment and sending the data transmission satisfies a threshold, wherein the second clear channel assessment process is performed at least in part based on the interval period satisfying the threshold.

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