Transmission countdown and improvement of beam-based channel access process

Abstract

The present disclosure provides systems, methods, and apparatus for a beam-based channel access countdown process. In one aspect, a channel detection beam may be allowed to include one or more transmit beams, and therefore may be different from the transmit beam used for transmission. Therefore, it is desirable to define a manner in which a channel access countdown process is performed. Some aspects described herein provide techniques and apparatus for a beam-based channel access countdown process. In some aspects, the systems, methods, and apparatus described herein provide a beam-based channel access countdown process that allows a single channel detection beam including multiple transmit beams to be utilized in association with determining the channel availability of multiple transmit beams, thereby improving the performance of beam-based directional transmissions.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority to U.S. Provisional Patent Application No. 62 / 878,052, filed on July 24, 2019, entitled “TRANSMISSION COUNTDOWN ANDIMPROVEMENTS FOR A BEAM BASED LISTEN-BEFORE-TALK PROCEDURE,” and U.S. Non-Provisional Patent Application No. 16 / 910,830, filed on June 24, 2020, entitled “TRANSMISSION COUNTDOWN ANDIMPROVEMENTS FOR A BEAM BASED CHANNEL ACCESS PROCEDURE,” which are hereby expressly incorporated herein by reference. Technical Field

[0003] Aspects of the present disclosure relate generally to wireless communications and techniques for transmission countdown and improvements in beam-based channel access procedures. Background Art

[0004] Wireless communication systems are widely deployed to provide a variety of telecommunication services, such as telephony, video, data, messaging, and broadcasting. Typical wireless communication systems may employ multiple access technologies that can support communication with multiple users by sharing available system resources (e.g., bandwidth, transmission power, etc.). Examples of such multiple access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, time division synchronous code division multiple access (TD-SCDMA) systems, and long term evolution (LTE). LTE / LTE-Advanced is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3GPP).

[0005] A wireless communication network may include multiple base stations (BS) that may support communication of multiple user equipments (UEs). User equipments (UEs) may communicate with base stations (BSs) via downlinks (DL) and uplinks (UL). DL (or forward link) refers to a communication link from a BS to a UE, and UL (or reverse link) refers to a communication link from a UE to a BS. As will be described in more detail herein, a BS may be referred to as a Node B, a nodeB (eNB) of LTE evolution, a gNB, an access point (AP), a radio head, a transmit receive point (TRP), a new radio (NR) BS, a 5G Node B, etc.

[0006] The above-mentioned multiple access technologies have been adopted by various telecommunication standards to provide a common protocol that enables different UEs to communicate at municipal, national, regional and even global levels. NR, which can also be referred to as 5G, is a set of enhancements to the LTE mobile standard promulgated by the Third Generation Partnership Project (3GPP). NR aims to better support mobile broadband Internet access by improving spectrum efficiency, reducing costs, improving services, utilizing new spectrum, and using orthogonal frequency division multiplexing (OFDM) with cyclic prefix (CP) on DL, CP-OFDM and / or SC-FDM (e.g., also known as discrete Fourier transform spread OFDM (DFT-s-OFDM)) on UL (or a combination thereof), better integrating with other open standards, and supporting beamforming, multiple-input multiple-output (MIMO) antenna technology and carrier aggregation. Summary of the invention

[0007] The systems, methods and devices of the present disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.

[0008] One innovative aspect of the subject matter described in the present disclosure can be implemented in a wireless communication method performed by a base station. The method may include: determining a set of user equipment (UE) to be scheduled in a transmission opportunity (TxOP); determining a set of transmit beams to be transmitted to the set of UEs; determining one or more channel sounding beams based at least in part on the determined set of transmit beams, wherein each of the one or more channel sounding beams includes a subset of the determined set of transmit beams; and performing a channel access countdown process for each of the one or more channel sounding beams.

[0009] In some aspects, the method may include, after completing the channel access countdown process for the channel detection beam including the subset of transmit beams, transmitting to a subset of the UE set using the subset of transmit beams included in the channel detection beams among the one or more channel detection beams.

[0010] In some aspects, for each of the one or more channel detection beams, the channel access countdown process is performed at least in part based on a corresponding set of determined channel access parameters, wherein the determined set of channel access parameters includes: a contention window size; a randomly selected value; or a delay period.

[0011] In some aspects, the method may include: determining that the specific subset of the set of transmit beams is unavailable based at least in part on performing the channel access countdown process for a channel detection beam that includes a specific subset of transmit beams; switching to one or more other channel detection beams based at least in part on the specific subset of transmit beams, wherein each of the one or more other channel detection beams includes one or more of the specific subset of transmit beams; and performing the channel access countdown process for each of the one or more other channel detection beams.

[0012] In some aspects, a counter value associated with the channel access countdown process for the channel sounding beam comprising the particular subset of transmit beams is reset in association with performing the channel access countdown process for at least one of the one or more other channel sounding beams.

[0013] In some aspects, a latency penalty is applied in association with performing the channel access countdown procedure for at least one of the one or more other channel sounding beams.

[0014] In some aspects, a counter value associated with the channel access countdown process for the channel acquisition beam comprising the particular subset of transmit beams is maintained in association with performing the channel access countdown process for at least one of the one or more other channel acquisition beams.

[0015] In some aspects, the counter value is maintained based at least in part on the at least one channel sounding beam being within a coverage area of ​​the channel sounding beam that includes the particular subset of transmit beams.

[0016] In some aspects, when performing the channel access countdown process for each of the one or more channel sounding beams, channel sounding is performed at least for a minimum sounding duration.

[0017] In some aspects, the minimum sounding duration matches a channel reservation signaling period.

[0018] Another innovative aspect of the subject matter described in the present disclosure can be implemented in an apparatus of a base station for wireless communication. The apparatus may include: a processing system configured to: determine a set of UEs to be scheduled in a TxOP; determine a set of transmit beams to be transmitted to the set of UEs; determine one or more channel detection beams based at least in part on the determined set of transmit beams, wherein each of the one or more channel detection beams includes a subset of the determined set of transmit beams; and perform a channel access countdown process for each of the one or more channel detection beams.

[0019] Another innovative aspect of the subject matter described in the present disclosure can be implemented in a non-transitory computer-readable medium. The non-transitory computer-readable medium can store one or more instructions for wireless communication. When the one or more instructions are executed by one or more processors of a base station, the one or more processors can be caused to: determine a set of UEs to be scheduled in a TxOP; determine a set of transmit beams to be sent to the set of UEs; determine one or more channel detection beams based at least in part on the determined set of transmit beams, wherein each of the one or more channel detection beams includes a subset of the determined set of transmit beams; and perform a channel access countdown process for each of the one or more channel detection beams.

[0020] Another innovative aspect of the subject matter described in the present disclosure can be implemented in an apparatus for wireless communication. The apparatus may include: a component for determining a set of UEs to be scheduled in a TxOP; a component for determining a set of transmit beams to be transmitted to the set of UEs; a component for determining one or more channel sounding beams based at least in part on the determined set of transmit beams, wherein each of the one or more channel sounding beams includes a subset of the determined set of transmit beams; and a component for performing a channel access countdown process for each of the one or more channel sounding beams.

[0021] Another innovative aspect of the subject matter described in the present disclosure can be implemented in a wireless communication method performed by a base station. The method may include: determining a set of transmit beams; determining one or more channel detection beams, each channel detection beam including a subset of the determined set of transmit beams; performing a channel access countdown process for each of the one or more channel detection beams; after completing the channel access countdown process for the channel detection beam, determining that a specific subset of the determined set of transmit beams is available; and determining a set of UEs to be scheduled in a TxOP based at least in part on the specific subset of transmit beams.

[0022] In some aspects, the method may include transmitting to the set of UEs using the particular subset of transmit beams.

[0023] In some aspects, for each of the one or more channel detection beams, the channel access countdown process is performed at least in part based on a corresponding set of determined channel access parameters, wherein the determined set of channel access parameters includes: a contention window size; a randomly selected value; or a delay period.

[0024] In some aspects, the method may include: determining that the determined other specific subset of the set of transmit beams is unavailable based at least in part on performing the channel access countdown process for a channel detection beam that includes another specific subset of transmit beams; switching to one or more other channel detection beams based at least in part on the other specific subset of transmit beams, wherein each of the one or more other channel detection beams includes one or more of the other specific subset of transmit beams; and performing the channel access countdown process for each of the one or more other channel detection beams.

[0025] In some aspects, a counter value associated with the channel access countdown process for the channel sounding beam comprising the other particular subset of transmit beams is reset in association with performing the channel access countdown process for at least one of the one or more other channel sounding beams.

[0026] In some aspects, a latency penalty is applied in association with performing the channel access countdown procedure for at least one of the one or more other channel sounding beams.

[0027] In some aspects, a counter value associated with the channel access countdown process for the channel acquisition beam comprising the other particular subset of transmit beams is maintained in association with performing the channel access countdown process for at least one of the one or more other channel acquisition beams.

[0028] In some aspects, the counter value is maintained based at least in part on the at least one channel sounding beam being within a coverage area of ​​the channel sounding beam that includes the other particular subset of transmit beams.

[0029] In some aspects, when performing the channel access countdown process for each of the one or more channel sounding beams, channel sounding is performed at least for a minimum sounding duration.

[0030] In some aspects, the minimum sounding duration matches a channel reservation signaling period.

[0031] Another innovative aspect of the subject matter described in the present disclosure can be implemented in a non-transitory computer-readable medium. The non-transitory computer-readable medium can store one or more instructions for wireless communication. When the one or more instructions are executed by one or more processors of a base station, the one or more processors can be caused to: determine a set of transmit beams; determine one or more channel detection beams, each channel detection beam including a subset of the determined set of transmit beams; perform a channel access countdown process for each of the one or more channel detection beams; after completing the channel access countdown process for the channel detection beam, determine that a specific subset of the determined set of transmit beams is available; and determine a set of UEs to be scheduled in a TxOP based at least in part on the specific subset of transmit beams.

[0032] Another innovative aspect of the subject matter described in the present disclosure can be implemented in an apparatus for wireless communication. The apparatus may include: a component for determining a set of transmit beams; a component for determining one or more channel detection beams, each of which includes a subset of the determined set of transmit beams; a component for performing a channel access countdown process for each of the one or more channel detection beams; a component for determining that a specific subset of the determined set of transmit beams is available after completing the channel access countdown process for the channel detection beams; and a component for determining a set of UEs to be scheduled in a TxOP based at least in part on the specific subset of transmit beams.

[0033] As generally described herein with reference to and illustrated by the accompanying drawings and description, aspects generally include a method, an apparatus, a system, a computer program product, a non-transitory computer-readable medium, a user equipment, a base station, a wireless communication device, or a processing system.

[0034] Details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the following description. Other features, aspects, and advantages will become apparent from the description, drawings, and claims. Note that the relative sizes of the following drawings may not be drawn to scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a block diagram conceptually illustrating an example of a wireless network 100 .

[0036] Figure 2 is a block diagram conceptually illustrating an example of a base station (BS) communicating with a user equipment (UE) in a wireless network.

[0037] Figure 3 , 4, 5A and 5B show diagrams of examples associated with transmission countdown and improvements for a beam-based channel access procedure.

[0038] Figure 6 and 7 is a diagram illustrating an example process performed, for example, by a BS.

[0039] The same reference numbers and names in different drawings represent the same elements.

[0040] Specific implementation method

[0041] To describe the innovative aspects of the present disclosure, the following description is directed to certain implementations. However, one of ordinary skill in the art will readily appreciate that the teachings herein can be applied in a variety of different ways. Some examples in the present disclosure are based on wireless and wired local area network (LAN) communications according to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 wireless standards, IEEE 802.3 Ethernet standards, and IEEE 1901 power line communications (PLC) standards. However, the described implementations may be implemented in any device, system, or network capable of sending and receiving radio frequency signals in accordance with any wireless communication standard, including any IEEE 802.11 standard, Bluetooth standard, Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Global System for Mobile Communications (GSM), GSM / General Packet Radio Service (GPRS), Enhanced Data GSM Environment (EDGE), Terrestrial Trunked Radio (TETRA), Wideband CDMA (W-CDMA), Evolution Data Optimized (EV-DO), 1xEV-DO, EV-DO RevA, EV-DO RevB, High Speed ​​Packet Access (HSPA), High Speed ​​Downlink Packet Access (HSDPA), High Speed ​​Uplink Packet Access (HSUPA), Evolved High Speed ​​Packet Access (HSPA+), Long Term Evolution (LTE), AMPS, or other known signals for communicating within a wireless, cellular, or Internet of Things (IoT) network, such as systems utilizing technology from 3G, 4G, or 5G or further implementations thereof.

[0042] In wireless communication systems such as 5G (NR) systems, spectrum sharing can be used (e.g., in millimeter wave (mmW) bands), which means that transmissions can be communicated in relatively narrow beams in different spatial directions on the same frequency band. In association with performing such beam-based directional transmissions, a channel access process associated with determining channel availability, such as a listen-before-talk (or listen-before-transmit) (LBT) process, can be used to determine the availability of a transmit beam to be used for a given transmission. In some cases, the channel access process can use a channel detection beam to evaluate channel availability. Various aspects of beam-based channel detection for spectrum sharing can be defined, such as a manner of determining a channel detection beam for a transmit beam, and a manner of adjusting transmission parameters, transmit power, or channel detection parameters (e.g., energy detection thresholds) to achieve fair detection and transmission.

[0043] However, in some cases, the channel detection beam may be allowed to include (in other words, contain) one or more transmit beams. Therefore, in some cases, the channel detection beam may be different from the transmit beam to be used for transmission. In other words, the channel detection beam may have a different coverage area from the transmit beam. Here, it is necessary to define a manner of performing a channel access countdown process associated with a channel detection beam that includes multiple transmit beams. Some aspects described herein provide techniques and apparatus for a beam-based channel access countdown process. It is worth noting that the term footprint in the context of a transmit beam may refer to the amount of interference that a beam may cause to one or more nearby receivers. In the context of a receive beam, the term footprint may refer to the sensitivity of a beam to other interference sources located near a receiver in a given direction.

[0044] Specific implementations of the subject matter described in the present disclosure may be implemented to achieve one or more of the following potential advantages. In some aspects, the techniques and apparatus described herein provide a beam-based channel access countdown process that may allow a single channel detection beam to be utilized in association with determining the channel availability of multiple transmit beams, which may include multiple transmit beams, thereby potentially improving the performance of beam-based directional transmissions. The techniques and apparatus described herein may also provide further advantages, namely simplifying the channel access countdown process at the base station and enabling the channel access countdown process to be implemented in association with beam-based directional transmissions. If the NR system can multiplex transmissions from different beams (e.g., synchronization signal blocks (SSBs), physical downlink shared channels (PDSCHs), physical downlink control channels (PDCCHs), and channel state information reference signals (CSI-RSs) scanned from the base station side; physical uplink control channels (PUCCHs), physical uplink shared channels (PUSCHs), and sounding reference signals (SRSs) scanned from the UE side), the beam-based channel access countdown process described herein may allow additional flexibility in the NR system.

[0045] Figure 1 1 is a block diagram conceptually illustrating an example of a wireless network 100. The wireless network 100 may be an LTE network or some other wireless network, such as a 5G or NR network. The wireless network 100 may include a plurality of BSs 110 (shown as BS 110a, BS 110b, BS 110c, and BS 110d) and other network entities. A BS is an entity that communicates with a user equipment (UE) and may also be referred to as a base station, NR BS, Node B, gNB, 5G node B (NB), access point, transmit receive point (TRP), etc. Each BS may provide communication coverage for a particular geographic area. In 3GPP, the term "cell" may refer to a coverage area of ​​a BS, a BS subsystem serving the coverage area, or a combination thereof, depending on the context in which the term is used.

[0046] A BS may provide communication coverage for a macro cell, a pico cell, a femto cell, and / or another type of cell, or a combination thereof. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs through service subscription. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs through service subscription. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG)). A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. In Figure 1 In the example shown, BS 110a may be a macro BS for macro cell 102a, BS 110b may be a pico BS for pico cell 102b, and BS 110c may be a femto BS for femto cell 102c. A BS may support one or more (e.g., three) cells. The terms "eNB", "base station", "NR BS", "gNB", "TRP", "AP", "node B", "5G NB", and "cell" may be used interchangeably herein.

[0047] In some examples, the cell is not necessarily stationary, and the geographic area of ​​the cell can move according to the location of the mobile BS. In some examples, the BSs can be interconnected with each other and to one or more other BSs or network nodes (not shown) in the access wireless network 100 through various types of backhaul interfaces (e.g., direct physical connections, virtual networks, or combinations thereof) using any suitable transport network.

[0048] The wireless network 100 may also include a relay station. A relay station is an entity that can receive data transmissions from an upstream station (e.g., a BS or a UE) and send data transmissions to a downstream station (e.g., a UE or a BS). A relay station may also be a UE that can relay transmissions for other UEs. Figure 1 In the example shown, a relay station 110d may communicate with the macro BS 110a and the UE 120d to facilitate communication between the BS 110a and the UE 120d. A relay station may also be referred to as a relay BS, a relay base station, a relay, or the like.

[0049] The wireless network 100 may be a heterogeneous network including different types of BSs (e.g., macro BSs, pico BSs, femto BSs, relay BSs, etc.). These different types of BSs may have different transmission power levels, different coverage areas, and different effects on interference in the wireless network 100. For example, a macro BS may have a high transmission power level (e.g., 5 to 40 watts), while a pico BS, a femto BS, and a relay BS may have a lower transmission power level (e.g., 0.1 to 2 watts).

[0050] A network controller 130 may be coupled to a set of BSs and may provide coordination and control for these BSs. The network controller 130 may communicate with the BSs via a backhaul. The BSs may also communicate with each other directly or indirectly, for example, via a wireless or wired backhaul.

[0051] UEs 120 (e.g., 120a, 120b, 120c) may be dispersed throughout the wireless network 100, and each UE may be stationary or mobile. UEs may also be referred to as access terminals, terminals, mobile stations, subscriber units, stations, etc. UEs may be cellular phones (e.g., smart phones), personal digital assistants (PDAs), wireless modems, wireless communication devices, handheld devices, laptop computers, cordless phones, wireless local loop (WLL) stations, tablet computers, cameras, gaming devices, netbooks, smartbooks, ultrabooks, medical devices or equipment, biometric sensors / devices, wearable devices (smart watches, smart clothing, smart glasses, smart wristbands, smart jewelry (e.g., smart rings, smart bracelets)), entertainment devices (e.g., music or video devices or satellite radios), vehicle components or sensors, smart meters / sensors, industrial manufacturing equipment, global positioning system devices, or any other suitable device configured to communicate via wireless or wired media.

[0052] Some UEs may be considered as machine type communication (MTC) or evolved or enhanced machine type communication (eMTC) UEs. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., which may communicate with a base station, another device (e.g., a remote device), or some other entity. For example, a wireless node may provide a connection to a network (e.g., a wide area network such as the Internet or a cellular network) or provide a connection to a network via a wired or wireless communication link. Some UEs may be considered as Internet of Things (IoT) devices, or may be implemented as NB-IoT (narrowband Internet of Things) devices. Some UEs may be considered as customer premises equipment (CPE). UE 120 may be included in a housing that houses components of UE 120 (e.g., a processor component, a memory component, a similar component, or a combination thereof).

[0053] Generally, any number of wireless networks can be deployed in a given geographic area. Each wireless network can support a specific RAT and can operate on one or more frequencies. RAT can also be referred to as radio technology, air interface, etc. Frequency can also be referred to as carrier, frequency channel, etc. Each frequency can support a single RAT in a given geographic area to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks can be deployed.

[0054] In some examples, access to the air interface may be scheduled, wherein a scheduling entity (e.g., a base station) allocates resources for communications between some or all devices and equipment within a service area or cell of the scheduling entity. In the present disclosure, as discussed further below, a scheduling entity may be responsible for scheduling, allocating, reconfiguring, and releasing resources for one or more dependent entities. That is, for scheduled communications, the dependent entities utilize resources allocated by the scheduling entity.

[0055] The base station is not the only entity that can act as a scheduling entity. That is, in some examples, the UE can act as a scheduling entity to schedule resources for one or more subordinate entities (e.g., one or more other UEs). In this example, the UE acts as a scheduling entity, and other UEs use the resources scheduled by the UE for wireless communication. The UE can act as a scheduling entity in a peer-to-peer (P2P) network, a mesh network, or other types of networks. In the mesh network example, in addition to communicating with the scheduling entity, the UEs can optionally communicate directly with each other.

[0056] Thus, in a wireless communication network having scheduled access to time-frequency resources and having a cellular configuration, a P2P configuration, and a mesh configuration, a scheduling entity and one or more slave entities may communicate using the scheduled resources.

[0057] In some aspects, two or more UEs 120 (e.g., shown as UE 120a and UE 120e) may communicate directly (e.g., without using base station 110 as an intermediary to communicate with each other) using one or more sidelink channels. For example, UE 120 may communicate using peer-to-peer (P2P) communication, device-to-device (D2D) communication, vehicle-to-everything (V2X) protocol (which may include vehicle-to-vehicle (V2V) protocol, vehicle-to-infrastructure (V2I) protocol, or similar protocol), mesh network, or similar network, or a combination thereof. In this case, UE 120 may perform scheduling operations, resource selection operations, and other operations described elsewhere herein as being performed by base station 110.

[0058] Figure 2 2 is a block diagram conceptually illustrating an example 200 of a base station (BS) 110 in communication with a UE 120. In some aspects, the base station 110 and the UE 120 may be, respectively. Figure 1 One of the base stations and one of the user equipment in the wireless network 100. The base station 110 may be equipped with T antennas 234a through 234t, and the UE 120 may be equipped with R antennas 252a through 252r, where in general T≥1 and R≥1.

[0059] At the base station 110, the transmit processor 220 may receive data from the data source 212 for one or more UEs, select one or more modulation and coding schemes (MCS) for each UE based at least in part on a channel quality indicator (CQI) received from the UE, process (e.g., encode and modulate) data for each UE based at least in part on the MCS selected for the UE, and provide data symbols for all UEs. The transmit processor 220 may also process system information (e.g., for semi-static resource partitioning information (SRPI), etc.) and control information (e.g., CQI requests, grants, upper layer signaling, etc.), and provide overhead symbols and control symbols. The transmit processor 220 may also generate reference symbols for reference signals (e.g., cell-specific reference signals (CRS)) and synchronization signals (e.g., primary synchronization signals (PSS) and secondary synchronization signals (SSS)). The transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on ​​data symbols, control symbols, overhead symbols, and / or reference symbols, if applicable, and may provide T output symbol streams to T modulators (MOD) 232a to 232t. Each modulator 232 may process a corresponding output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator 232 may further process (e.g., convert to analog, amplify, filter, and up-convert) the output sample stream to obtain a downlink signal. The T downlink signals from modulators 232a to 232t may be transmitted via T antennas 234a to 234t, respectively. According to various aspects described in more detail below, a synchronization signal may be generated using position coding to convey additional information.

[0060] At the UE 120, antennas 252a to 252r may receive downlink signals from the base station 110 or other base stations and may provide received signals to demodulators (DEMODs) 254a to 254r, respectively. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) the received signal to obtain input samples. Each demodulator 254 may further process the input samples (e.g., for OFDM) to obtain received symbols. The MIMO detector 256 may obtain received symbols from all R demodulators 254a to 254r, perform MIMO detection on the received symbols (if applicable), and provide detected symbols. The receive processor 258 may process (e.g., demodulate and decode) the detected symbols, provide decoded data for the UE 120 to the data sink 260, and provide decoded control information and system information to the controller or processor (controller / processor) 280. The channel processor may determine reference signal received power (RSRP), received signal strength indicator (RSSI), reference signal received quality (RSRQ), channel quality indicator (CQI), etc. In some aspects, one or more components of UE 120 may be included in a housing.

[0061] On the uplink, at the UE 120, a transmit processor 264 may receive and process data from a data source 262 and control information from a controller / processor 280 (e.g., for reports including RSRP, RSSI, RSRQ, CQI, etc.). The transmit processor 264 may also generate reference symbols for one or more reference signals. The symbols from the transmit processor 264 may be precoded by a TX MIMO processor 266 (if applicable), further processed by modulators 254a through 254r (e.g., for DFT-s-OFDM, CP-OFDM, etc.), and transmitted to the base station 110. At the base station 110, uplink signals from the UE 120 and other UEs may be received by the antenna 234, processed by the demodulator 232, detected by the MIMO detector 236 (if applicable), and further processed by the receive processor 238 to obtain decoded data and control information sent by the UE 120. The receive processor 238 may provide decoded data to a data sink 239 and provide decoded control information to a controller or processor (i.e., controller / processor) 240. The base station 110 may include a communication unit 244 and communicate with the network controller 130 via the communication unit 244. The network controller 130 may include a communication unit 294, a controller or processor (i.e., controller / processor) 290, and a memory 292.

[0062] The controller / processor 240 of the base station 110, the controller / processor 280 of the UE 120, or Figure 2 Any other component of the base station 110 may perform one or more techniques associated with transmission countdown and improvement of beam-based channel access procedures, as described in more detail elsewhere herein. For example, the controller / processor 240 of the base station 110, the controller / processor 280 of the UE 120, or Figure 2 Any other component (or combination of components) may perform or direct, for example Figure 6 The process of 600 Figure 7 The operations of process 700 or other processes described herein. Memories 242 and 282 may store data and program codes for base station 110 and UE 120, respectively. Scheduler 246 may schedule data transmissions of UEs on downlink, uplink, or a combination thereof.

[0063] When executed by the controller / processor 240 or other processors and modules at the base station 110, the stored program code may cause the base station 110 to perform Figure 6 The process of 600 Figure 7 The operations described in process 700 or other processes described herein may be performed. Scheduler 246 may schedule UEs for data transmission on the downlink, uplink, or a combination thereof.

[0064] The base station 110 may include components for performing one or more operations described herein, such as Figure 6 The process of 600 Figure 7 700 or other processes described herein. In some aspects, such components may include combining Figure 2 One or more components of base station 110 are described.

[0065] Although Figure 2 The blocks in the 200 and 210 are shown as distinct components, but the functionality described with respect to the blocks may be implemented in a single hardware, software, or combined component, or in various combinations of components. For example, the functionality described with respect to the transmit processor 264, the receive processor 258, the TX MIMO processor 266, or another processor may be performed by or under the control of the controller / processor 280.

[0066] In some implementations, the controller / processor 240 may be a component of a processing system. A processing system may generally refer to a system or series of machines or components that receives inputs and processes the inputs to produce a set of outputs that may be delivered to other systems or components, such as the base station 110. For example, the processing system of the base station 110 may refer to a system that includes various other components or subcomponents of the base station 110.

[0067] The processing system of the base station 110 may interface with other components of the base station 110, and may process information (e.g., input or signal) received from other components, output information to other components, and the like. For example, a chip or modem of the base station 110 may include a processing system, a first interface for receiving or acquiring information, and a second interface for outputting, sending, or providing information. In some cases, the first interface may refer to an interface between a processing system and a receiver of a chip or modem, so that the base station 110 may receive information or signal input, and the information may be passed to the processing system. In some cases, the second interface may refer to an interface between a processing system and a transmitter of a chip or modem, so that the base station 110 may send information output from the chip or modem. One of ordinary skill in the art will readily recognize that the second interface may also obtain or receive information or signal input, and the first interface may also output, send, or provide information.

[0068] Figure 3 and Figure 4 is a diagram illustrating an example associated with transmission countdown and improvements for a beam-based channel access procedure.

[0069] Figure 3 is a diagram illustrating an example 300 in which a channel access countdown process is performed on one or more channel sounding beams after UE scheduling.

[0070] like Figure 3 As shown in FIG. 305 , in some aspects, a base station 110 (eg, Figure 1 and 2 The base station 110 depicted and described in the foregoing may determine a set of UEs 120 (UE1-UE4, e.g., Figure 1 and 2 For example, one or more UEs 120 depicted and described in Figure 3 As shown, the base station may determine a set of UEs including UE1, UE2, UE3 and UE4 to be scheduled in the TxOP.

[0071] As shown in reference numeral 310, the base station may determine a set of transmit beams to be transmitted to the set of UEs. Figure 3 As shown, the base station can determine a transmission beam B1 to be sent to UE1, a transmission beam B2 to be sent to UE2, a transmission beam B3 to be sent to UE3, and a transmission beam B4 to be sent to UE4.

[0072] As indicated by reference numeral 315, the base station may determine one or more channel sounding beams (sometimes referred to as one or more composite beams) based at least in part on the determined set of transmit beams. In some aspects, a channel sounding beam is a beam used in association with determining whether a channel associated with one or more transmit beams included in the channel sounding beam is available (e.g., so that the base station can transmit using the one or more transmit beams). In some aspects, each of the one or more channel sounding beams may include (e.g., spatially surround) a subset of the determined set of transmit beams. That is, each of the one or more channel sounding beams may have a coverage area that overlaps with the coverage area of ​​the subset of the determined set of transmit beams. As described above, the term footprint in the context of a transmit beam may refer to the interference that the beam may cause to one or more nearby receivers.

[0073] For example, Figure 3 As shown, the base station can determine a channel detection beam B12 including the transmission beam B1 and the transmission beam B2, and a channel detection beam B34 including the transmission beam B3 and the transmission beam B4.

[0074] As shown at reference numeral 320, the base station may perform a channel access countdown procedure for each of the one or more channel sounding beams. For example, the base station may perform a channel access countdown procedure for channel sounding beam B12 and may (separately) perform a channel access countdown procedure for channel sounding beam B34.

[0075] In some aspects, for a given channel detection beam, a base station may perform a channel access countdown process based at least in part on a corresponding set of channel access parameters determined by the base station. The set of channel access parameters may include, for example, a contention window (CW) size, a randomly selected value N, and a delay period. In some aspects, the base station may determine the CW size based at least in part on, for example, the success / failure of one or more previous transmissions or the type of service to be sent. In some aspects, the base station may determine the randomly selected value as, for example, a randomly selected value within a range from 0 to the CW size. In some aspects, the base station may determine the delay or deferral period based at least in part on technology-specific parameters, a countdown increment (e.g., one time slot of X microseconds (μs)), or the type of service to be sent.

[0076] In some aspects, when performing a channel access countdown process, the base station may count down a counter value from a randomly selected value N to a zero value. In some aspects, the base station may begin counting down when the length of time that a channel associated with a channel detection beam is idle is equal to a delay period. Here, after the channel is idle for the length of the delay period, the base station may decrement the counter value at each time interval (e.g., at each Xμs time slot) in which the channel is detected as available. If the channel is detected as busy during the channel access countdown process, the base station may freeze the counter value, wait until the channel is detected as idle for another delay period, and continue counting down. In some aspects, the base station may send a transmission when the counter value reaches zero. In some aspects, the base station may perform a channel access countdown process separately for each of one or more channel detection beams.

[0077] In some aspects, after completing a channel access countdown process for a channel sounding beam that includes a subset of transmit beams, the base station may transmit to a subset of the set of UEs using a subset of transmit beams included in a channel sounding beam in one or more channel sounding beams. For example, the base station may complete a channel access countdown process for channel sounding beam B12 (e.g., when a counter value of a channel access countdown process associated with channel sounding beam B12 reaches zero), and may transmit to UE1 and UE2 using transmit beams B1 and B2, respectively. Similarly, the base station may complete a channel access countdown process for channel sounding beam B34 (e.g., when a counter value of a channel access countdown process associated with channel sounding beam B34 reaches zero, which may be different from the time when the base station completes the channel access countdown process for channel sounding beam B12), and may transmit to UE3 and UE4 using transmit beams B3 and B4, respectively.

[0078] Figure 4 is a diagram illustrating an example 400 in which UE scheduling is performed after a channel access countdown procedure is performed for one or more channel sounding beams.

[0079] like Figure 4 As shown in the figure 405, the base station 110 (eg Figure 1 and 2 The base station 110 depicted and described in the foregoing may determine a set of transmit beams (eg, a set of transmit beams for which availability is to be determined). Figure 4 As shown, the base station can determine the transmission beam B1, transmission beam B2, transmission beam B3 and transmission beam B4 for which availability is to be determined.

[0080] As indicated by reference numeral 410, the base station may determine one or more channel detection beams based at least in part on the determined set of transmit beams. In some aspects, the channel detection beam is a beam used in association with determining whether a channel associated with one or more transmit beams included in the channel detection beam is available (e.g., such that the base station may transmit using the one or more transmit beams). In some aspects, each of the one or more channel detection beams may include (e.g., spatially surround) a subset of the determined set of transmit beams. That is, each of the one or more channel detection beams may have a coverage area that overlaps with the coverage area of ​​the subset of the determined set of transmit beams. As described above, the term footprint in the context of a transmit beam may refer to the interference that the beam may cause to one or more nearby receivers. For example, if Figure 4 As shown, the base station can determine a channel detection beam B12 including the transmission beam B1 and the transmission beam B2, and a channel detection beam B34 including the transmission beam B3 and the transmission beam B4.

[0081] As shown at 415, the base station may perform a channel access countdown procedure for each of the one or more channel acquisition beams. For example, the base station may perform a channel access countdown procedure for channel acquisition beam B12 and may (separately) perform a channel access countdown procedure for channel acquisition beam B34. In some aspects, the base station may perform a channel access countdown procedure similar to that of combining Figure 3 The described approach performs a channel access process for a given channel detection beam.

[0082] As indicated by reference numeral 420, the base station may determine that a specific subset of the determined set of transmit beams is available after completing a channel access countdown process for the channel sounding beam. For example, after completing a channel access countdown process for channel sounding beam B12 (e.g., when a counter value associated with the channel access process for channel sounding beam B12 reaches zero), the base station may determine that transmit beams B1 and B2 are available.

[0083] As further indicated by reference numeral 420, the base station may determine a set of UEs (UE1 and UE2, e.g., Figure 1 and 2 For example, one or more UEs 120 depicted and described in Figure 4 As shown, the base station may determine a set of UEs including UE1 and UE2 to be scheduled in the TxOP based at least in part on transmit beams B1 and B2. In some aspects, the set of UEs may include UEs to which the base station may send a subset of transmit beams. For example, the base station may determine that transmit beam B1 is to be sent to UE1, and transmit beam B2 is to be sent to UE2, and may determine a set of UEs including UE1 and UE2 accordingly.

[0084] In some aspects, the base station may transmit to the set of UEs using a subset of transmit beams. For example, the base station may transmit to UE1 and UE2 using transmit beams B1 and B2, respectively, based at least in part on determining that transmit beams B1 and B2 are available.

[0085] In some aspects, in combination Figure 3 and Figure 4 In any of the described scenarios, the base station may iterate between performing a channel access countdown process and UE scheduling. For example, the base station may determine a transmit beam set and one or more channel detection beams. The base station may perform a channel access process for one or more channel detection beams. However, in some cases, the base station may determine that a subset of the determined transmit beam set is unavailable based at least in part on performing a channel access countdown process for a channel detection beam that includes a subset of the transmit beams. For example, the base station may determine that a subset of the determined transmit beam set is unavailable based at least in part on detecting that a channel associated with a channel detection beam that includes a subset of the transmit beams is busy within a threshold time period (based at least in part on an indication received by the base station). In this case, the base station may switch beams or UEs, and may restart the channel access countdown process. For example, the base station may switch to one or more other channel detection beams, each of which includes one or more of the subset of the transmit beams, and may perform a channel access countdown process for each of the one or more other channel detection beams in a manner similar to that described throughout the text. In some aspects, alignment between one or more other channel sounding beams may be achieved by self-delay (in other words, the base station may wait until a counter value associated with each of the one or more other channel sounding beams reaches zero before transmitting using any subset of the transmit beams).

[0086] Figure 5A and 5BAn example 500 is shown of a base station switching a channel sounding beam and restarting a channel access countdown process based at least in part on a determination that a subset of transmit beams are unavailable.

[0087] exist Figure 5A In the example, the base station determines a transmission beam set including transmission beam B1, transmission beam B2, transmission beam B3, and transmission beam B4. In addition, the base station determines a channel detection beam B1234 including transmission beams B1 to B4. Figure 5A As shown in reference numeral 505 in FIG, the base station may perform a channel access countdown process for channel detection beam B 1234. However, as shown in reference numeral 510, the base station may determine that the determined set of transmit beams B1 to B4 is unavailable based at least in part on performing a channel access countdown process for channel detection beam B 1234 (e.g., based at least in part on detecting that a channel associated with channel detection beam B 1234 is busy within a threshold time period).

[0088] like Figure 5B As shown by reference numeral 515, the base station may switch to channel detection beam B12 (including transmission beams B1 and B2) and channel detection beam B34 (including transmission beams B3 and B4). Figure 5B As shown by reference numeral 520 in the figure, the base station can restart the channel access countdown process for channel detection beams B12 and B34.

[0089] In addition to the described examples, in certain scenarios (e.g., when additional data is to be sent, when the priority of the service changes), it may be desirable to switch the channel detection beam during the channel access countdown process. Therefore, in some aspects, the base station may abandon the ongoing channel access countdown process, switch to another channel detection beam, and start a new channel access countdown process. In some aspects, for example, when the base station switches to another channel detection beam, the base station may reset the counter value when performing the channel access countdown process. For example, when the base station switches from a channel detection beam including a subset of the transmit beam set to one or more other channel detection beams, each of the one or more other channel detection beams including at least one subset of the transmit beam, the base station may reset the counter value when performing the channel access countdown process for a given one of the one or more other channel detection beams. In some aspects, the base station may apply a waiting time penalty in association with performing the channel access countdown process for another channel detection beam. In some aspects, the base station may evaluate a latency penalty to ensure fairness when switching to another channel sounding beam (eg, so that the base station does not gain an unfair channel access advantage by switching to another channel sounding beam).

[0090] Alternatively, in some aspects, when the base station switches to another channel acquisition beam, the base station can maintain the counter value while performing the channel access countdown procedure. For example, when the base station switches from a channel acquisition beam that includes a subset of the set of transmit beams to one or more other channel acquisition beams, each of the one or more other channel acquisition beams including at least a subset of the transmit beams as described throughout, the base station can maintain the counter value while performing the channel access countdown procedure for a given one of the one or more other channel acquisition beams. In some aspects, the base station can maintain the counter value for a given one of the one or more other channel acquisition beams based at least in part on the given channel acquisition beam being within the coverage area of ​​the channel acquisition beam that includes the subset of the transmit beams.

[0091] In some aspects, when performing a channel access countdown process for each of one or more channel sounding beams, the base station can be configured to perform channel sounding for at least a minimum sounding duration. In some aspects, the minimum sounding duration can match the channel reservation signaling period. For example, such aspects can be used when the reservation signal / message is to be repeated once at a specific time interval (e.g., once every X time slots / microseconds (μs)). Here, the minimum sounding duration can be at least a minimum amount of time before transmission (e.g., X time slots / μs). In some aspects, when the base station switches the channel sounding beam (e.g., after a given TxOP), the minimum sounding duration limit can be applied.

[0092] Figure 6 6 is a diagram illustrating an example process 600 performed, for example, by a BS. Example process 600 illustrates a base station 110 (e.g., Figure 1 and 2 The base station 110 depicted and described in the Figure 1 performs operations associated with transmission countdown and improvement of a beam-based channel access procedure.

[0093] like Figure 6 As shown, in some aspects, process 600 may include determining a set of UEs to be scheduled in a TxOP (block 610). For example, base station 110 (e.g., by using transmit processor 220, receive processor 238, controller / processor 240, memory 242) may determine a set of UEs 120 to be scheduled in a TxOP (e.g., Figure 1 and 2 One or more UEs 120 depicted and described in ).

[0094] like Figure 6As further shown in FIG. 6 , in some aspects, process 600 may include determining a set of transmit beams to be sent to a set of UEs (block 620). For example, base station 110 (e.g., using transmit processor 220, receive processor 238, controller / processor 240, memory 242) may determine a set of transmit beams to be sent to a set of UEs.

[0095] like Figure 6 As further shown in FIG. 6 , in some aspects, process 600 may include determining one or more channel sounding beams based at least in part on the determined set of transmit beams (block 630). For example, base station 110 (e.g., using transmit processor 220, receive processor 238, controller / processor 240, memory 242) may determine one or more channel sounding beams based at least in part on the determined set of transmit beams. In some aspects, each of the one or more channel sounding beams includes a subset of the determined set of transmit beams.

[0096] like Figure 6 As further shown in FIG. 6 , in some aspects, process 600 may include performing a channel access countdown process for each of the one or more channel sounding beams (block 640). For example, base station 110 (e.g., using transmit processor 220, receive processor 238, controller / processor 240, memory 242) may perform a channel access countdown process for each of the one or more channel sounding beams.

[0097] Process 600 may include additional aspects, such as any single aspect or any combination of aspects described below or in combination with one or more other processes described elsewhere herein.

[0098] In the first aspect, after completing the channel access countdown process for the channel detection beam including the subset of the transmission beam, the base station can use the subset of the transmission beam included in the channel detection beam in one or more channel detection beams to transmit to a subset of the UE set.

[0099] In a second aspect, either alone or in combination with the first aspect, a channel access countdown process is performed for each of one or more channel detection beams based at least in part on a corresponding set of determined channel access parameters, wherein the determined set of channel access parameters includes: a contention window size; a randomly selected value; or a delay period.

[0100] In a third aspect, alone or in combination with one or more of the first and second aspects, the base station may determine that the determined specific subset of the set of transmit beams is unavailable based at least in part on performing a channel access countdown process for a channel detection beam that includes a specific subset of transmit beams. Here, the base station may switch to one or more other channel detection beams based at least in part on the specific subset of transmit beams. In some aspects, each of the one or more other channel detection beams includes one or more of the specific subset of transmit beams. The base station may perform a channel access countdown process for each of the one or more other channel detection beams.

[0101] In a fourth aspect, either alone or in combination with one or more of the first to third aspects, a counter value associated with a channel access countdown process for a channel detection beam comprising a specific subset of transmit beams is reset in association with performing a channel access countdown process for at least one of one or more other channel detection beams.

[0102] In a fifth aspect, alone or in combination with one or more of the first to fourth aspects, a waiting time penalty is applied in association with performing a channel access countdown procedure for at least one of the one or more other channel sounding beams.

[0103] In a sixth aspect, either alone or in combination with one or more of the first to fifth aspects, a counter value associated with a channel access countdown process for a channel detection beam comprising a specific subset of transmit beams is maintained in association with performing a channel access countdown process for at least one channel detection beam of one or more other channel detection beams.

[0104] In a seventh aspect, alone or in combination with one or more of the first to sixth aspects, a counter value is maintained based at least in part on at least one channel sounding beam within a coverage area of ​​the channel sounding beam that includes a particular subset of transmit beams.

[0105] In an eighth aspect, alone or in combination with one or more of the first to seventh aspects, when a channel access countdown process is performed for each of one or more channel sounding beams, channel sounding is performed at least for a minimum sounding duration.

[0106] In a ninth aspect, alone or in combination with one or more of the first to eighth aspects, the minimum detection duration matches a channel reservation signaling period.

[0107] Although Figure 6 Example blocks of process 600 are shown, but in some aspects process 600 may include additional blocks, fewer blocks, different blocks, or different Figure 6Additionally or alternatively, two or more blocks of process 600 may be executed in parallel.

[0108] Figure 7 700 is a diagram illustrating an example process 700 performed, for example, by a BS. Example process 700 illustrates a base station 110 (e.g., Figure 1 and 2 The base station 110 depicted and described in the Figure 1 performs operations associated with transmission countdown and improvement of a beam-based channel access procedure.

[0109] like Figure 7 As shown, in some aspects, process 700 may include determining a set of transmit beams (block 710). For example, base station 110 (e.g., using transmit processor 220, receive processor 238, controller / processor 240, memory 242) may determine a set of transmit beams.

[0110] like Figure 7 As further shown in FIG. 7 , in some aspects, process 700 may include determining one or more channel sounding beams, each channel sounding beam comprising a subset of the determined set of transmit beams (block 720). For example, base station 110 (e.g., using transmit processor 220, receive processor 238, controller / processor 240, memory 242) may determine one or more channel sounding beams, each channel sounding beam comprising a subset of the determined set of transmit beams.

[0111] like Figure 7 As further shown in FIG. 7 , in some aspects, process 700 may include performing a channel access countdown process for each of the one or more channel sounding beams (block 730). For example, base station 110 (e.g., using transmit processor 220, receive processor 238, controller / processor 240, memory 242) may perform a channel access countdown process for each of the one or more channel sounding beams.

[0112] like Figure 7 As further shown in FIG. 7 , in some aspects, process 700 may include determining that a particular subset of the determined set of transmit beams is available after completing a channel access countdown process for the channel sounding beam (block 740). For example, base station 110 (e.g., using transmit processor 220, receive processor 238, controller / processor 240, memory 242) may determine that a particular subset of the determined set of transmit beams is available after completing a channel access countdown process for the channel sounding beam.

[0113] like Figure 7As further shown in FIG. 7 , in some aspects, process 700 may include determining a set of UEs 120 to be scheduled in a TxOP based at least in part on a particular subset of transmit beams (e.g., Figure 1 and 2 1 and 120) (block 750). For example, base station 110 (e.g., using transmit processor 220, receive processor 238, controller / processor 240, memory 242) may determine a set of UEs 120 to schedule in a TxOP based at least in part on a particular subset of transmit beams.

[0114] Process 700 may include additional aspects, such as any single aspect or any combination of aspects described below or in combination with one or more other processes described elsewhere herein.

[0115] In a first aspect, a base station may transmit to a set of UEs using a specific subset of transmit beams.

[0116] In a second aspect, either alone or in combination with the first aspect, a channel access countdown process is performed for each of one or more channel detection beams based at least in part on a corresponding set of determined channel access parameters, wherein the determined set of channel access parameters includes: a contention window size; a randomly selected value; or a delay period.

[0117] In a third aspect, alone or in combination with one or more of the first and second aspects, the base station may determine that the determined another specific subset of the set of transmit beams is unavailable based at least in part on performing a channel access countdown process for a channel detection beam that includes another specific subset of the transmit beams. Here, the base station may switch to one or more other channel detection beams based at least in part on the other specific subset of the transmit beams. In some aspects, each of the one or more other channel detection beams includes one or more of the other specific subset of the transmit beams. The base station may perform a channel access countdown process for each of the one or more other channel detection beams.

[0118] In a fourth aspect, either alone or in combination with one or more of the first to third aspects, a counter value associated with a channel access countdown process for a channel detection beam comprising another specific subset of transmit beams is reset in association with performing a channel access countdown process for at least one of one or more other channel detection beams.

[0119] In a fifth aspect, alone or in combination with one or more of the first to fourth aspects, a waiting time penalty is applied in association with performing a channel access countdown procedure for at least one of the one or more other channel sounding beams.

[0120] In a sixth aspect, either alone or in combination with one or more of the first to fifth aspects, a counter value associated with a channel access countdown process for a channel detection beam comprising another specific subset of transmit beams is maintained in association with performing a channel access countdown process for at least one channel detection beam of one or more other channel detection beams.

[0121] In a seventh aspect, alone or in combination with one or more of the first to sixth aspects, a counter value is maintained based at least in part on at least one channel acquisition beam being within a coverage area of ​​a channel acquisition beam that includes another specific subset of transmit beams.

[0122] In an eighth aspect, alone or in combination with one or more of the first to seventh aspects, when a channel access countdown process is performed for each of one or more channel sounding beams, channel sounding is performed at least for a minimum sounding duration.

[0123] In a ninth aspect, alone or in combination with one or more of the first to eighth aspects, the minimum detection duration matches a channel reservation signaling period.

[0124] Although Figure 7 Example blocks of process 700 are shown, but in some aspects process 700 may include additional blocks, fewer blocks, different blocks, or different Figure 7 Additionally or alternatively, two or more blocks of process 700 may be executed in parallel.

[0125] The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the aspects to the precise forms disclosed. Modifications and variations are possible in light of the disclosure or may be acquired from practice of the aspects.

[0126] As used herein, the term "component" is intended to be broadly interpreted as hardware, firmware, or a combination of hardware and software. As used herein, a processor is implemented in hardware, firmware, or a combination of hardware and software. As used herein, the phrase "based on" is intended to be broadly interpreted as "based at least in part on."

[0127] Some aspects are described herein in conjunction with a threshold value. As used herein, satisfying a threshold value may refer to a value greater than a threshold value, greater than or equal to a threshold value, less than a threshold value, less than or equal to a threshold value, equal to a threshold value, or not equal to a threshold value.

[0128] As used herein, a phrase referring to "at least one" of a list of items refers to any combination of those items, including single members. For example, "at least one of a, b, or c" is intended to cover: a, b, c, ab, ac, bc, and abc.

[0129] The various illustrative logics, logic blocks, modules, circuits, and algorithmic processes described in conjunction with the aspects disclosed herein may be implemented as electronic hardware, computer software, or a combination of both. The interchangeability of hardware and software has been generally described in terms of functionality and illustrated in the various illustrative components, blocks, modules, circuits, and processes described above. Whether such functionality is implemented in hardware or software depends on the specific application and design constraints on the overall system.

[0130] The hardware and data processing apparatus for implementing the various illustrative logics, logic blocks, modules and circuits described in conjunction with the aspects disclosed herein can be implemented or executed with a general purpose single-chip or multi-chip 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, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor can be a microprocessor or any conventional processor, controller, microcontroller or state machine. The processor can also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration. In some aspects, specific processes and methods can be performed by circuits specific to a given function.

[0131] In one or more aspects, the functions described may be implemented in hardware, digital electronic circuitry, computer software, firmware (including the structures disclosed in this specification and their equivalents), or any combination thereof. Aspects of the subject matter described in this specification may also be implemented as one or more computer programs, i.e., one or more modules of computer program instructions, encoded on computer storage media for execution by a data processing apparatus or to control the operation of the data processing apparatus.

[0132] If implemented in software, the function can be stored or transferred to a computer-readable medium as one or more instructions or codes. The process of the method or algorithm disclosed herein can be implemented in a software module executable by a processor, and the software module can reside on a computer-readable medium. Computer-readable media include computer storage media and communication media, and the communication media include any medium capable of transmitting a computer program from one place to another. The storage medium can be any available medium accessible by a computer. As an example and not limitation, this computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage or other magnetic storage device, or any other medium that can be used to store the required program code in the form of an instruction or data structure and can be accessed by a computer. In addition, any connection can be appropriately referred to as a computer-readable medium. The disk (Disk) and disk (disc) used herein include high-density optical disks (CDs), laser disks, optical disks, digital versatile disks (DVDs), floppy disks and blue-ray disks, wherein the disk (Disk) usually copies data magnetically, and the disk (disc) copies data optically with lasers. The above combination should also be included in the scope of computer-readable media. Additionally, the operations of a method or algorithm may be implemented as one or any combination or set of codes and instructions on a machine-readable medium and a computer-readable medium, which may be incorporated into a computer program product.

[0133] Various modifications to the aspects described in this disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the spirit or scope of the disclosure. Therefore, the disclosure is not intended to be limited to the aspects shown herein, but to be consistent with the broadest scope consistent with the claims, principles, and novel features disclosed herein.

[0134] Additionally, one of ordinary skill in the art will readily appreciate that the terms "upper" and "lower" are sometimes used to facilitate description of the drawings and indicate relative positions corresponding to the orientation of the drawings on a page with a correct orientation, and may not reflect the correct orientation of any device implemented.

[0135] Certain features described in this specification in the context of separate aspects may also be implemented in combination in a single aspect. Conversely, various features described in the context of a single aspect may also be implemented in multiple aspects alone or in any suitable subcombination. Furthermore, although features may be described above as functioning in certain combinations, and even initially claimed as such, in some cases one or more features from a claimed combination may be deleted from the combination, and a claimed combination may be directed to a subcombination or a variation of a subcombination.

[0136] Similarly, although the operations are described in a particular order in the accompanying drawings, this should not be understood as requiring the operations to be performed in the particular order or sequence shown, or requiring the execution of all the operations shown to obtain the desired results. In addition, the accompanying drawings may schematically depict one or more example processes in the form of a flow chart. However, other operations not shown may be combined in the schematically shown example processes. For example, one or more additional operations may be performed before, after, simultaneously, or between any of the operations shown. In some cases, multitasking and parallel processing may be advantageous. In some cases, multitasking and parallel processing may be advantageous. In addition, the separation of various system components in the above aspects should not be understood as requiring such separation in all aspects, and it should be understood that the described program components and systems can generally be integrated in a single software product or encapsulated in multiple software products. In addition, other aspects are also within the scope of the following claims. In some cases, the actions listed in the claims may be performed in different orders and still obtain the desired results.

Claims

1. A wireless communication method performed by a base station, comprising: Determining a set of user equipments UE to be scheduled in a transmission opportunity TxOP; Determining a transmit beam for each UE in the set of UEs; determining one or more channel sounding beams based at least in part on the determined set of transmit beams, wherein each of the one or more channel detection beams includes a plurality of transmit beams in the determined set of transmit beams; as well as A channel access countdown process is performed for each of the one or more channel sounding beams.

2. The method according to claim 1 further includes, after completing the channel access countdown process for a channel detection beam including multiple transmit beams in the one or more channel detection beams, using the multiple transmit beams included in the channel detection beam to transmit to a subset of the UE set.

3. The method according to claim 1, wherein: For each of the one or more channel sounding beams, performing the channel access countdown process based at least in part on a corresponding set of determined channel access parameters, the determined set of channel access parameters comprising: Contention window size; a randomly selected value; or Delay cycle.

4. The method according to claim 1, further comprising: determining that the particular subset of the set of transmit beams is unavailable based at least in part on performing the channel access countdown process for a channel sounding beam that includes the determined particular subset of the set of transmit beams; switching to one or more other channel sounding beams based at least in part on the particular subset of transmit beams, wherein each of the one or more other channel sounding beams comprises one or more of the particular subset of transmit beams; and The channel access countdown process is performed for each of the one or more other channel sounding beams.

5. A method according to claim 4, wherein a counter value associated with the channel access countdown process for the channel detection beam comprising the specific subset of transmit beams is reset in association with performing the channel access countdown process for at least one of the one or more other channel detection beams.

6. The method of claim 4, wherein a latency penalty is applied in association with performing the channel access countdown procedure for at least one of the one or more other channel sounding beams.

7. A method according to claim 4, wherein a counter value associated with the channel access countdown process for the channel detection beam comprising the specific subset of transmit beams is maintained in association with performing the channel access countdown process for at least one channel detection beam among the one or more other channel detection beams.

8. The method of claim 7, wherein the counter value is maintained based at least in part on the at least one channel sounding beam being within a coverage area of ​​a channel sounding beam that includes the particular subset of transmit beams.

9. The method according to claim 1, wherein: When the channel access countdown process is performed for each of the one or more channel sounding beams, channel sounding is performed at least for a minimum sounding duration.

10. The method of claim 9, wherein the minimum detection duration matches a channel reservation signaling period.

11. A wireless communication method performed by a base station, comprising: Determine a transmit beam set; determining one or more channel sounding beams based at least in part on the determined set of transmit beams, each channel sounding beam comprising a plurality of transmit beams in the determined set of transmit beams; performing a channel access countdown process for each of the one or more channel sounding beams; After completing the channel access countdown process for the channel detection beam, determining that channels associated with the plurality of transmit beams included in the channel detection beam are available; as well as A set of user equipments UE is scheduled in a transmission opportunity TxOP, the set of UE being based at least in part on the plurality of transmit beams included in the channel sounding beam.

12. The method of claim 11, further comprising transmitting to the set of UEs using the multiple transmit beams.

13. The method according to claim 11, wherein: For each of the one or more channel sounding beams, performing the channel access countdown process based at least in part on a corresponding set of determined channel access parameters, the determined set of channel access parameters comprising: Contention window size; a randomly selected value; or Delay cycle.

14. The method according to claim 11, further comprising: Determining that the determined particular subset of the set of transmit beams is unavailable based at least in part on performing the channel access countdown process for a channel sounding beam that includes the particular subset of transmit beams; switching to one or more other channel sounding beams based at least in part on the particular subset of transmit beams, wherein each of the one or more other channel sounding beams comprises one or more of the particular subset of transmit beams; and The channel access countdown process is performed for each of the one or more other channel sounding beams.

15. A method according to claim 14, wherein a counter value associated with the channel access countdown process for the channel detection beam comprising the specific subset of transmit beams is reset in association with performing the channel access countdown process for at least one of the one or more other channel detection beams.

16. The method of claim 14, wherein a latency penalty is applied in association with performing the channel access countdown procedure for at least one of the one or more other channel sounding beams.

17. A method according to claim 14, wherein a counter value associated with the channel access countdown process for the channel detection beam that includes the specific subset of transmit beams is maintained in association with performing the channel access countdown process for at least one of the one or more other channel detection beams.

18. The method of claim 17, wherein the counter value is maintained based at least in part on the at least one channel sounding beam being within a coverage area of ​​the channel sounding beam that includes the particular subset of transmit beams.

19. The method according to claim 11, wherein: When the channel access countdown process is performed for each of the one or more channel sounding beams, channel sounding is performed at least for a minimum sounding duration.

20. The method of claim 19, wherein the minimum detection duration matches a channel reservation signaling period.

21. A base station for wireless communication, comprising: A processing system configured to: Determining a set of user equipments UE to be scheduled in a transmission opportunity TxOP; Determining a transmit beam for each UE in the set of UEs; determining one or more channel sounding beams based at least in part on the determined set of transmit beams, wherein each of the one or more channel detection beams includes a plurality of transmit beams in the determined set of transmit beams; as well as A channel access countdown process is performed for each of the one or more channel sounding beams.

22. The base station according to claim 21 further includes an interface for outputting to a subset of the UE set using the multiple transmit beams included in the channel detection beam after completing the channel access countdown process for the channel detection beam including multiple transmit beams in the one or more channel detection beams.

23. The base station according to claim 21, wherein: For each of the one or more channel sounding beams, performing the channel access countdown process based at least in part on a corresponding set of determined channel access parameters, the determined set of channel access parameters comprising: Contention window size; a randomly selected value; or Delay cycle.

24. The base station of claim 21, wherein the processing system is further configured to: determining that the particular subset of the set of transmit beams is unavailable based at least in part on performing the channel access countdown process for a channel sounding beam that includes the determined particular subset of the set of transmit beams; switching to one or more other channel sounding beams based at least in part on the particular subset of transmit beams, wherein each of the one or more other channel sounding beams comprises one or more of the particular subset of transmit beams; and The channel access countdown process is performed for each of the one or more other channel sounding beams.

25. A base station according to claim 24, wherein a counter value associated with the channel access countdown process for the channel detection beam including the specific subset of transmit beams is reset in association with performing the channel access countdown process for at least one of the one or more other channel detection beams.

26. The base station of claim 24, wherein a latency penalty is applied in association with performing the channel access countdown procedure for at least one of the one or more other channel sounding beams.

27. A base station according to claim 24, wherein a counter value associated with the channel access countdown process for the channel detection beam comprising the specific subset of transmit beams is maintained in association with performing the channel access countdown process for at least one channel detection beam among the one or more other channel detection beams.

28. The base station of claim 27, wherein the counter value is maintained based at least in part on the at least one channel sounding beam being within a coverage area of ​​the channel sounding beam that includes the particular subset of transmit beams.

29. The base station according to claim 21, wherein: When the channel access countdown process is performed for each of the one or more channel sounding beams, channel sounding is performed at least for a minimum sounding duration.

30. The base station of claim 29, wherein the minimum detection duration matches a channel reservation signaling period.

31. A base station for wireless communication, comprising: A processing system configured to: Determine a transmit beam set; determining one or more channel sounding beams based at least in part on the determined set of transmit beams, each channel sounding beam comprising a plurality of transmit beams in the determined set of transmit beams; performing a channel access countdown process for each of the one or more channel sounding beams; After completing the channel access countdown process for the channel detection beam, determining that channels associated with the plurality of transmit beams included in the channel detection beam are available; as well as A set of user equipments UE is scheduled in a transmission opportunity TxOP, the set of UE being based at least in part on the plurality of transmit beams included in the channel sounding beam.

32. The base station of claim 31, further comprising an interface for outputting to the set of UEs using the multiple transmit beams.

33. The base station according to claim 31, wherein: For each of the one or more channel sounding beams, performing the channel access countdown process based at least in part on a corresponding set of determined channel access parameters, the determined set of channel access parameters comprising: Contention window size; a randomly selected value; or Delay cycle.

34. The base station of claim 31 , wherein the processing system is further configured to: Determining that the determined particular subset of the set of transmit beams is unavailable based at least in part on performing the channel access countdown process for a channel sounding beam that includes the particular subset of transmit beams; switching to one or more other channel sounding beams based at least in part on the particular subset of transmit beams, wherein each of the one or more other channel sounding beams comprises one or more of the particular subset of transmit beams; and The channel access countdown process is performed for each of the one or more other channel sounding beams.

35. A base station according to claim 34, wherein a counter value associated with the channel access countdown process for the channel detection beam including the specific subset of transmit beams is reset in association with performing the channel access countdown process for at least one of the one or more other channel detection beams.

36. The base station of claim 34, wherein a latency penalty is applied in association with performing the channel access countdown procedure for at least one of the one or more other channel sounding beams.

37. A base station according to claim 34, wherein a counter value associated with the channel access countdown process for the channel detection beam comprising the specific subset of transmit beams is maintained in association with performing the channel access countdown process for at least one of the one or more other channel detection beams.

38. The base station of claim 37, wherein the counter value is maintained based at least in part on the at least one channel sounding beam being within a coverage area of ​​the channel sounding beam that includes the particular subset of transmit beams.

39. The base station according to claim 31, wherein: When the channel access countdown process is performed for each of the one or more channel sounding beams, channel sounding is performed at least for a minimum sounding duration.

40. The base station of claim 39, wherein the minimum detection duration matches a channel reservation signaling period.

41. A non-transitory computer-readable medium storing one or more instructions for wireless communication, the one or more instructions comprising: One or more instructions that, when executed by one or more processors of a base station, cause the one or more processors to: Determining a set of user equipments UE to be scheduled in a transmission opportunity TxOP; Determining a transmit beam for each UE in the set of UEs; determining one or more channel sounding beams based at least in part on the determined set of transmit beams, wherein each of the one or more channel detection beams includes a plurality of transmit beams in the determined set of transmit beams; as well as A channel access countdown process is performed for each of the one or more channel sounding beams.

42. A non-temporary computer-readable medium according to claim 41, wherein when the one or more instructions are executed by the one or more processors, the one or more processors further cause the one or more processors to transmit to a subset of the UE set using the multiple transmit beams included in the channel detection beam after completing the channel access countdown process for the channel detection beam including multiple transmit beams in the one or more channel detection beams.

43. The non-transitory computer readable medium of claim 41, wherein: For each of the one or more channel sounding beams, performing the channel access countdown process based at least in part on a corresponding set of determined channel access parameters, the determined set of channel access parameters comprising: Contention window size; a randomly selected value; or Delay cycle.

44. The non-transitory computer readable medium of claim 41 , wherein the one or more instructions, when executed by the one or more processors, further cause the one or more processors to: determining that the particular subset of the set of transmit beams is unavailable based at least in part on performing the channel access countdown process for a channel sounding beam that includes the determined particular subset of the set of transmit beams; switching to one or more other channel sounding beams based at least in part on the particular subset of transmit beams, wherein each of the one or more other channel sounding beams comprises one or more of the particular subset of transmit beams; and The channel access countdown process is performed for each of the one or more other channel sounding beams.

45. A non-transitory computer-readable medium according to claim 44, wherein a counter value associated with the channel access countdown process for the channel detection beam comprising the specific subset of transmit beams is reset in association with performing the channel access countdown process for at least one of the one or more other channel detection beams.

46. ​​The non-transitory computer-readable medium of claim 44, wherein a latency penalty is applied in association with performing the channel access countdown process for at least one of the one or more other channel sounding beams.

47. A non-transitory computer-readable medium according to claim 44, wherein a counter value associated with the channel access countdown process for the channel detection beam that includes the specific subset of transmit beams is maintained in association with performing the channel access countdown process for at least one of the one or more other channel detection beams.

48. The non-transitory computer-readable medium of claim 47, wherein the counter value is maintained based at least in part on the at least one channel sounding beam being within a coverage area of ​​the channel sounding beam that includes the particular subset of transmit beams.

49. The non-transitory computer readable medium of claim 41, wherein: When the channel access countdown process is performed for each of the one or more channel sounding beams, channel sounding is performed at least for a minimum sounding duration.

50. The non-transitory computer-readable medium of claim 49, wherein the minimum sounding duration matches a channel reservation signaling period.

51. A non-transitory computer readable medium storing one or more instructions for wireless communication, the one or more instructions comprising: One or more instructions that, when executed by one or more processors of a base station, cause the one or more processors to: Determine a transmit beam set; determining one or more channel sounding beams based at least in part on the determined set of transmit beams, each channel sounding beam comprising a plurality of transmit beams in the determined set of transmit beams; performing a channel access countdown process for each of the one or more channel sounding beams; After completing the channel access countdown process for the channel detection beam, determining that channels associated with the plurality of transmit beams included in the channel detection beam are available; as well as A set of user equipments UE is scheduled in a transmission opportunity TxOP, the set of UE being based at least in part on the plurality of transmit beams included in the channel sounding beam.

52. The non-transitory computer-readable medium of claim 51, wherein the one or more instructions, when executed by the one or more processors, further cause the one or more processors to transmit to the set of UEs using the multiple transmit beams.

53. The non-transitory computer readable medium of claim 51, wherein: For each of the one or more channel sounding beams, performing the channel access countdown process based at least in part on a corresponding set of determined channel access parameters, the determined set of channel access parameters comprising: Contention window size; a randomly selected value; or Delay cycle.

54. The non-transitory computer readable medium of claim 51 , wherein the one or more instructions, when executed by the one or more processors, further cause the one or more processors to: Determining that the determined particular subset of the set of transmit beams is unavailable based at least in part on performing the channel access countdown process for a channel sounding beam that includes the particular subset of transmit beams; switching to one or more other channel sounding beams based at least in part on the particular subset of transmit beams, wherein each of the one or more other channel sounding beams comprises one or more of the particular subset of transmit beams; and The channel access countdown process is performed for each of the one or more other channel sounding beams.

55. A non-transitory computer-readable medium according to claim 54, wherein a counter value associated with the channel access countdown process for the channel detection beam that includes the specific subset of transmit beams is reset in association with performing the channel access countdown process for at least one of the one or more other channel detection beams.

56. The non-transitory computer-readable medium of claim 54, wherein a latency penalty is applied in association with performing the channel access countdown process for at least one of the one or more other channel sounding beams.

57. A non-transitory computer-readable medium according to claim 54, wherein a counter value associated with the channel access countdown process for the channel detection beam that includes the specific subset of transmit beams is maintained in association with performing the channel access countdown process for at least one of the one or more other channel detection beams.

58. The non-transitory computer-readable medium of claim 57, wherein the counter value is maintained based at least in part on the at least one channel sounding beam being within a coverage area of ​​the channel sounding beam that includes the particular subset of transmit beams.

59. The non-transitory computer readable medium of claim 51, wherein: When the channel access countdown process is performed for each of the one or more channel sounding beams, channel sounding is performed at least for a minimum sounding duration.

60. The non-transitory computer-readable medium of claim 59, wherein the minimum sounding duration matches a channel reservation signaling period.

61. An apparatus for wireless communication, comprising: means for determining a set of user equipments UE to be scheduled in a transmission opportunity TxOP; means for determining a transmit beam for each UE in the set of UEs; means for determining one or more channel sounding beams based at least in part on the determined set of transmit beams, wherein each of the one or more channel detection beams includes a plurality of transmit beams in the determined set of transmit beams; as well as Means for performing a channel access countdown procedure for each of the one or more channel sounding beams.

62. The apparatus according to claim 61 further comprises a component for transmitting to a subset of the UE set using the multiple transmit beams included in the channel detection beam after completing the channel access countdown process for a channel detection beam including multiple transmit beams in the one or more channel detection beams.

63. The apparatus of claim 61, wherein: For each of the one or more channel sounding beams, performing the channel access countdown process based at least in part on a corresponding set of determined channel access parameters, the determined set of channel access parameters comprising: Contention window size; a randomly selected value; or Delay cycle.

64. The apparatus of claim 61, further comprising: means for determining that the particular subset of the set of transmit beams is unavailable based at least in part on performing the channel access countdown process for channel sounding beams that include the determined particular subset of the set of transmit beams; means for switching to one or more other channel sounding beams based at least in part on the particular subset of transmit beams, wherein each of the one or more other channel sounding beams comprises one or more of the particular subset of transmit beams; and Means for performing the channel access countdown procedure for each of the one or more other channel sounding beams.

65. An apparatus according to claim 64, wherein a counter value associated with the channel access countdown process for the channel detection beam comprising the specific subset of transmit beams is reset in association with performing the channel access countdown process for at least one of the one or more other channel detection beams.

66. The apparatus of claim 64, wherein a latency penalty is applied in association with performing the channel access countdown process for at least one of the one or more other channel sounding beams.

67. An apparatus according to claim 64, wherein a counter value associated with the channel access countdown process for the channel detection beam comprising the specific subset of transmit beams is maintained in association with performing the channel access countdown process for at least one of the one or more other channel detection beams.

68. The apparatus of claim 67, wherein the counter value is maintained based at least in part on the at least one channel sounding beam being within a coverage area of ​​the channel sounding beam that includes the particular subset of transmit beams.

69. The apparatus of claim 61, wherein when the channel access countdown process is performed for each of the one or more channel sounding beams, channel sounding is performed at least for a minimum sounding duration.

70. The apparatus of claim 69, wherein the minimum detection duration matches a channel reservation signaling period.

71. An apparatus for wireless communication, comprising: A component for determining a set of transmit beams; means for determining one or more channel sounding beams based at least in part on the determined set of transmit beams, each channel sounding beam comprising a plurality of the determined set of transmit beams; means for performing a channel access countdown procedure for each of the one or more channel sounding beams; A means for determining that channels associated with the plurality of transmit beams included in the channel detection beam are available after completing the channel access countdown process for the channel detection beam; as well as Means for scheduling a set of user equipments UE in a transmission opportunity TxOP, the set of UEs being based at least in part on the plurality of transmit beams included in the channel sounding beam.

72. The apparatus of claim 71 further comprising means for transmitting to the set of UEs using the plurality of transmit beams.

73. The apparatus of claim 71, wherein: For each of the one or more channel sounding beams, performing the channel access countdown process based at least in part on a corresponding set of determined channel access parameters, the determined set of channel access parameters comprising: Contention window size; a randomly selected value; or Delay cycle.

74. The apparatus of claim 71, further comprising: means for determining that the determined particular subset of the set of transmit beams is unavailable based at least in part on performing the channel access countdown process for a channel sounding beam comprising the particular subset of transmit beams; means for switching to one or more other channel sounding beams based at least in part on the particular subset of transmit beams, wherein each of the one or more other channel sounding beams comprises one or more of the particular subset of transmit beams; and Means for performing the channel access countdown procedure for each of the one or more other channel sounding beams.

75. An apparatus according to claim 74, wherein a counter value associated with the channel access countdown process for the channel detection beam comprising the specific subset of transmit beams is reset in association with performing the channel access countdown process for at least one of the one or more other channel detection beams.

76. The apparatus of claim 74, wherein a latency penalty is applied in association with performing the channel access countdown process for at least one of the one or more other channel sounding beams.

77. An apparatus according to claim 74, wherein a counter value associated with the channel access countdown process for the channel detection beam comprising the specific subset of transmit beams is maintained in association with performing the channel access countdown process for at least one of the one or more other channel detection beams.

78. The apparatus of claim 77, wherein the counter value is maintained based at least in part on the at least one channel sounding beam being within a coverage area of ​​the channel sounding beam that includes the particular subset of transmit beams.

79. The apparatus of claim 71, wherein: When the channel access countdown process is performed for each of the one or more channel sounding beams, channel sounding is performed at least for a minimum sounding duration.

80. The apparatus of claim 79, wherein the minimum sounding duration matches a channel reservation signaling period.

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