WO2021232340A1

WO2021232340A1 - Channel busy measurements for sidelink communications

Info

Publication number: WO2021232340A1
Application number: PCT/CN2020/091530
Authority: WO
Inventors: Xiaoxia Zhang; Jing Sun; Chih-Hao Liu; Yisheng Xue; Changlong Xu; Ozcan Ozturk
Original assignee: Qualcomm Incorporated
Priority date: 2020-05-21
Filing date: 2020-05-21
Publication date: 2021-11-25

Abstract

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may perform a channel busy measurement for each listen-before-talk (LBT) subband of an unlicensed radio frequency spectrum band and determine whether to use the one or more LBT subbands for sidelink communications with another UE. The channel busy measurement may include a channel occupancy ratio (CR) measurement or a channel busy ratio (CBR). The UE may determine an availability of the LBT subband based on performing the measurements for each LBT subband. The UE may perform a scheduling operation for a sidelink message to another UE using the available LBT subbands. The UEs may communicate according to the scheduling operation.

Description

CHANNEL BUSY MEASUREMENTS FOR SIDELINK COMMUNICATIONS

FIELD OF TECHNOLOGY

The following relates generally to wireless communications and more specifically to channel busy measurements for sidelink communications.

BACKGROUND

Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power) . Examples of such multiple-access systems include fourth generation (4G) systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which may be referred to as New Radio (NR) systems. These systems may employ technologies such as code division multiple access (CDMA) , time division multiple access (TDMA) , frequency division multiple access (FDMA) , orthogonal FDMA (OFDMA) , or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM) . A wireless multiple-access communications system may include one or more base stations or one or more network access nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE) .

SUMMARY

The described techniques relate to improved methods, systems, devices, and apparatuses that support channel busy measurements for sidelink communications. Generally, the described techniques provide for a user equipment (UE) to perform a channel busy measurement for each listen-before-talk (LBT) subband of an unlicensed radio frequency spectrum band and determine whether to use the one or more LBT subbands for sidelink communications with another UE. In some cases, the channel busy measurement may include a channel occupancy ratio (CR) measurement or a channel busy ratio (CBR) . The UE may determine an availability of the LBT subband based on performing the measurements for each LBT subband (e.g., based on a CR limit or a quality of service (QoS) parameter associated with the CBR measurement) . The UE may perform a scheduling operation for a sidelink message to another UE using the available LBT subbands. The UEs may communicate according to the scheduling operation, which may reduce interference and latency at the UE, among other benefits.

A method of wireless communications at a first UE is described. The method may include performing a channel busy measurement for each of a set of LBT subbands of an unlicensed radio frequency spectrum band associated with sidelink communications, determining an availability of individual LBT subbands of the set of LBT subbands for sidelink communications at the first UE based on the respective channel busy measurement, and performing a scheduling operation for a sidelink message to a second UE based on the determined availability of individual LBT subbands of the set of LBT subbands.

An apparatus for wireless communications at a first UE is described. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to perform a channel busy measurement for each of a set of LBT subbands of an unlicensed radio frequency spectrum band associated with sidelink communications, determine an availability of individual LBT subbands of the set of LBT subbands for sidelink communications at the first UE based on the respective channel busy measurement, and perform a scheduling operation for a sidelink message to a second UE based on the determined availability of individual LBT subbands of the set of LBT subbands.

Another apparatus for wireless communications at a first UE is described. The apparatus may include means for performing a channel busy measurement for each of a set of LBT subbands of an unlicensed radio frequency spectrum band associated with sidelink communications, determining an availability of individual LBT subbands of the set of LBT subbands for sidelink communications at the first UE based on the respective channel busy measurement, and performing a scheduling operation for a sidelink message to a second UE based on the determined availability of individual LBT subbands of the set of LBT subbands.

A non-transitory computer-readable medium storing code for wireless communications at a first UE is described. The code may include instructions executable by a processor to perform a channel busy measurement for each of a set of LBT subbands of an unlicensed radio frequency spectrum band associated with sidelink communications, determine an availability of individual LBT subbands of the set of LBT subbands for sidelink communications at the first UE based on the respective channel busy measurement, and perform a scheduling operation for a sidelink message to a second UE based on the determined availability of individual LBT subbands of the set of LBT subbands.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, performing the channel busy measurement may include operations, features, means, or instructions for determining a CR measurement for each of the set of LBT subbands over a set of time resources and a total number of time resources of the set of time resources associated with a successful LBT procedure.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, determining the availability of individual LBT subbands may include operations, features, means, or instructions for determining that one or more individual LBT subbands may be available based on respective CR measurements for the one or more individual LBT subbands and a CR threshold for each of the set of LBT subbands.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining a priority associated with the sidelink message, determining a CR threshold based on the priority associated with the sidelink message, and determining whether one or more individual LBT subbands may be available based on respective CR measurements for the one or more individual LBT subbands and the CR threshold, where the sidelink message may be scheduled on each of the one or more individual LBT subbands determined to be available.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that none of the one or more individual LBT subbands may be available based on the respective CR measurements for each of the one or more individual LBT subbands exceeding the CR threshold, and refraining from performing the scheduling operation on the one or more individual LBT subbands based on determining that none of the one or more individual LBT subbands may be available.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining that at least one subband of the one or more individual LBT subbands may be unavailable based on the respective CR measurement for the at least one subband exceeding the CR threshold, and dropping transmission of the sidelink message over all of the one or more individual LBT subbands based on determining that the at least one subband may be unavailable.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining an average CR measurement for the set of LBT subbands based on respective CR measurements for each of the set of LBT subbands, and performing the scheduling operation for the sidelink message on the set of LBT subbands based on the average CR measurement being below a CR threshold.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining an average CR measurement for the set of LBT subbands based on respective CR measurements for each of the set of LBT subbands, and performing the scheduling operation for the sidelink message on one or more LBT subbands excluding the set of LBT subbands based on the average CR measurement exceeding a CR threshold.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, performing the channel busy measurement may include operations, features, means, or instructions for determining a first CR measurement for a primary subband of the set of LBT subbands over a set of time resources and a total number of time resources of the set of time resources associated with a successful LBT procedure, and determining a second CR measurement for a secondary subband of the set of LBT subbands, where the scheduling operation may be performed based on the first and second CR measurements.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for refraining from performing the scheduling operation for the sidelink message on the set of LBT subbands based on both the first CR measurement and the second CR measurement exceeding a CR threshold.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for performing the scheduling operation for the sidelink message on the primary subband based on determining that the first CR measurement may be below a CR threshold for the primary subband.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for performing the scheduling operation for the sidelink message on each of the set of LBT subbands having respective CR measurements below the CR threshold.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the primary subband for a first slot may be different from the primary subband for a second slot.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the second CR measurement may be performed via a different set of time resources compared to the first CR measurement.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining a CBR measurement for each of the set of LBT subbands over a set of time resources.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, determining the CBR measurement may include operations, features, means, or instructions for determining a respective received signal strength indicator (RSSI) for each of the set of LBT subbands over the set of time resources, determining that the respective RSSIs for one or more LBT subbands of the set of LBT subbands exceed a respective RSSI threshold, and determining the CBR measurement for a first time resource based on the one or more LBT subbands.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining a first set of QoS parameters associated with the sidelink message, determining a second set of QoS parameters of a LBT subband of the set of LBT subbands based on a respective CBR measurement for the LBT subband, and performing the scheduling operation for the sidelink message on the LBT subband based on the second set of QoS parameters satisfying the first set of QoS parameters.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining a first set of QoS parameters associated with the sidelink message, determining a second set of QoS parameters of a LBT subband of the set of LBT subbands based on a respective CBR measurement for the LBT subband, and refraining from performing the scheduling operation for the sidelink message on the LBT subband based on the second set of QoS parameters failing to satisfy the first set of QoS parameters.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining a first set of QoS parameters associated with the sidelink message, determining a respective sets of QoS parameters for the set of LBT subbands based on respective CBR measurements for the set of LBT subbands, and refraining from performing the scheduling operation for the sidelink message on any of the set of LBT subbands based on at least one of the respective sets of QoS parameters failing to satisfy the first set of QoS parameters.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining a first set of QoS parameters associated with the sidelink message, determining an average CBR measurement for the set of LBT subbands based on respective CBR measurements for each of the set of LBT subbands, determining an average set of QoS parameters based on the average CBR measurement, and performing the scheduling operation for the sidelink message on the set of LBT subbands based on the average set of QoS parameters satisfying the first set of QoS parameters.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining a first set of QoS parameters associated with the sidelink message, determining a first CBR measurement for a primary subband of the set of LBT subbands, determining a primary set of QoS parameters for the primary subband based on the first CBR measurement, and performing the scheduling operation for the sidelink message on the set of LBT subbands based on the primary set of QoS parameters satisfying the first set of QoS parameters.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the scheduling operation may be performed independent of a second CBR measurement of a secondary subband of the set of LBT subbands.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the primary subband semi-statically or randomly configured for each slot of a set of time resources of the unlicensed radio frequency spectrum band.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the channel busy measurement includes one of a CR measurement or a CBR measurement.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a wire less communications system that supports channel busy measurements for sidelink communications in accordance with aspects of the present disclosure.

FIG. 2 illustrates an example of a wireless communications system that supports channel busy measurements for sidelink communications in accordance with aspects of the present disclosure.

FIG. 3 illustrates an example of a channel diagram that supports channel busy measurements for sidelink communications in accordance with aspects of the present disclosure.

FIG. 4 illustrates an example of a process flow that supports channel busy measurements for sidelink communications in accordance with aspects of the present disclosure.

FIGs. 5 and 6 show block diagrams of devices that support channel busy measurements for sidelink communications in accordance with aspects of the present disclosure.

FIG. 7 shows a block diagram of a communications manager that supports channel busy measurements for sidelink communications in accordance with aspects of the present disclosure.

FIG. 8 shows a diagram of a system including a device that supports channel busy measurements for sidelink communications in accordance with aspects of the present disclosure.

FIGs. 9 through 14 show flowcharts illustrating methods that support channel busy measurements for sidelink communications in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

In some examples, sidelink operations may utilize an unlicensed frequency spectrum for communications between one or more user equipments (UEs) . As more UEs use the unlicensed frequency spectrum, the channels being used may become congested and as such, congestion control may be implemented at the UE to reduce congestion. For example, the UE may perform a channel occupancy ratio (CR) measurement or a channel busy ratio (CBR) measurement (e.g., including a sidelink received signal strength indicator (RSSI) measurement) . The channel busy measurement, such as a CBR or CR measurement, may account for a listen-before-talk (LBT) failure or intra-radio access technology (RAT) interference. However, the LBT failure and inter-RAT interference may vary from one LBT subband to another (e.g., due to channel, or channel subband, based access to Wi-Fi and potentially wideband operation on the New Radio Unlicensed (NR-U) sidelink) . Thus, improved techniques for performing a channel busy measurement for sidelink communications are desired.

The techniques described herein may enable a UE to perform a channel busy measurement, such as a CBR or CR measurement, for each LBT subband, which may account for LBT failure and interference at different LBT subbands among other benefits. In some examples, there may be multiple types of sidelink CR measurements. In a first type, for each LBT subband, the UE may measure the total number of sub-channels used for a transmission in one or more slots and granted slots divided by the total number of configured sub-channels available for transmission having a successful LBT. A second type of sidelink CR measurement may be similar to the first type, however, the UE may perform the measurement for a primary LBT subband. Similarly, the UE may perform a CBR measurement for each LBT subband.

In some cases, UE may determine a scheduling operation for a sidelink message with another UE based on the results of the channel busy measurements for each LBT subband. For example, if one or more LBT subbands satisfy a CR limit associated with a CR measurement, a quality of service (QoS) parameter associated with the CBR measurement, or additional parameters related to the channel busy measurement for each LBT subband, the UE may schedule a sidelink transmission on one or more of the LBT subbands. The UE may indicate the scheduling operation to another UE. In some cases, the UE and the other UE may communicate according to the scheduling operation.

Aspects of the disclosure are initially described in the context of wireless communications systems. Additional aspects of the disclosure are described with reference to a channel diagram and a process flow. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to channel busy measurements for sidelink communications.

FIG. 1 illustrates an example of a wireless communications system 100 that supports channel busy measurements for sidelink communications in accordance with aspects of the present disclosure. The wireless communications system 100 may include one or more base stations 105, one or more UEs 115, and a core network 130. In some examples, the wireless communications system 100 may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some examples, the wireless communications system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission critical) communications, low latency communications, communications with low-cost and low-complexity devices, or any combination thereof.

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

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

The base stations 105 may communicate with the core network 130, or with one another, or both. For example, the base stations 105 may interface with the core network 130 through one or more backhaul links 120 (e.g., via an S1, N2, N3, or other interface) . The base stations 105 may communicate with one another over the backhaul links 120 (e.g., via an X2, Xn, or other interface) either directly (e.g., directly between base stations 105) , or indirectly (e.g., via core network 130) , or both. In some examples, the backhaul links 120 may be or include one or more wireless links.

One or more of the base stations 105 described herein may include or may be referred to by a person having ordinary skill in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB) , a next-generation NodeB or a giga-NodeB (either of which may be referred to as a gNB) , a Home NodeB, a Home eNodeB, or other suitable terminology.

A UE 115 may include or may be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where the “device” may also be referred to as a unit, a station, a terminal, or a client, among other examples. A UE 115 may also include or may be referred to as a personal electronic device such as a cellular phone, a personal digital assistant (PDA) , a tablet computer, a laptop computer, or a personal computer. In some examples, a UE 115 may include or be referred to as a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine type communications (MTC) device, among other examples, which may be implemented in various objects such as appliances, or vehicles, meters, among other examples.

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

The UEs 115 and the base stations 105 may wirelessly communicate with one another via one or more communication links 125 over one or more carriers. The term “carrier” may refer to a set of radio frequency spectrum resources having a defined physical layer structure for supporting the communication links 125. For example, a carrier used for a communication link 125 may include a portion of a radio frequency spectrum band (e.g., a bandwidth part (BWP) ) that is operated according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR) . Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information) , control signaling that coordinates operation for the carrier, user data, or other signaling. The wireless communications system 100 may support communication with a UE 115 using carrier aggregation or multi-carrier operation. A UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers according to a carrier aggregation configuration. Carrier aggregation may be used with both frequency division duplexing (FDD) and time division duplexing (TDD) component carriers.

In some examples (e.g., in a carrier aggregation configuration) , a carrier may also have acquisition signaling or control signaling that coordinates operations for other carriers. A carrier may be associated with a frequency channel (e.g., an evolved universal mobile telecommunication system terrestrial radio access (E-UTRA) absolute radio frequency channel number (EARFCN) ) and may be positioned according to a channel raster for discovery by the UEs 115. A carrier may be operated in a standalone mode where initial acquisition and connection may be conducted by the UEs 115 via the carrier, or the carrier may be operated in a non-standalone mode where a connection is anchored using a different carrier (e.g., of the same or a different radio access technology) .

The communication links 125 shown in the wireless communications system 100 may include uplink transmissions from a UE 115 to a base station 105, or downlink transmissions from a base station 105 to a UE 115. Carriers may carry downlink or uplink communications (e.g., in an FDD mode) or may be configured to carry downlink and uplink communications (e.g., in a TDD mode) .

A carrier may be associated with a particular bandwidth of the radio frequency spectrum, and in some examples the carrier bandwidth may be referred to as a “system bandwidth” of the carrier or the wireless communications system 100. For example, the carrier bandwidth may be one of a number of determined bandwidths for carriers of a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 megahertz (MHz) ) . Devices of the wireless communications system 100 (e.g., the base stations 105, the UEs 115, or both) may have hardware configurations that support communications over a particular carrier bandwidth or may be configurable to support communications over one of a set of carrier bandwidths. In some examples, the wireless communications system 100 may include base stations 105 or UEs 115 that support simultaneous communications via carriers associated with multiple carrier bandwidths. In some examples, each served UE 115 may be configured for operating over portions (e.g., a sub-band, a BWP) or all of a carrier bandwidth.

Signal waveforms transmitted over a carrier may be made up of multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM) ) . In a system employing MCM techniques, a resource element may consist of one symbol period (e.g., a duration of one modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both) . Thus, the more resource elements that a UE 115 receives and the higher the order of the modulation scheme, the higher the data rate may be for the UE 115. A wireless communications resource may refer to a combination of a radio frequency spectrum resource, a time resource, and a spatial resource (e.g., spatial layers or beams) , and the use of multiple spatial layers may further increase the data rate or data integrity for communications with a UE 115.

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

The time intervals for the base stations 105 or the UEs 115 may be expressed in multiples of a basic time unit which may, for example, refer to a sampling period of T _s= 1/ (Δf _max·N _f) seconds, where Δf _max may represent the maximum supported subcarrier spacing, and N _f may represent the maximum supported discrete Fourier transform (DFT) size. Time intervals of a communications resource may be organized according to radio frames each having a specified duration (e.g., 10 milliseconds (ms) ) . Each radio frame may be identified by a system frame number (SFN) (e.g., ranging from 0 to 1023) .

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

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

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

Each base station 105 may provide communication coverage via one or more cells, for example a macro cell, a small cell, a hot spot, or other types of cells, or any combination thereof. The term “cell” may refer to a logical communication entity used for communication with a base station 105 (e.g., over a carrier) and may be associated with an identifier for distinguishing neighboring cells (e.g., a physical cell identifier (PCID) , a virtual cell identifier (VCID) , or others) . In some examples, a cell may also refer to a geographic coverage area 110 or a portion of a geographic coverage area 110 (e.g., a sector) over which the logical communication entity operates. Such cells may range from smaller areas (e.g., a structure, a subset of structure) to larger areas depending on various factors such as the capabilities of the base station 105. For example, a cell may be or include a building, a subset of a building, or exterior spaces between or overlapping with geographic coverage areas 110, among other examples.

A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by the UEs 115 with service subscriptions with the network provider supporting the macro cell. A small cell may be associated with a lower-powered base station 105, as compared with a macro cell, and a small cell may operate in the same or different (e.g., licensed, unlicensed) frequency bands as macro cells. Small cells may provide unrestricted access to the UEs 115 with service subscriptions with the network provider or may provide restricted access to the UEs 115 having an association with the small cell (e.g., the UEs 115 in a closed subscriber group (CSG) , the UEs 115 associated with users in a home or office) . A base station 105 may support one or multiple cells and may also support communications over the one or more cells using one or multiple component carriers.

In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., MTC, narrowband IoT (NB-IoT) , enhanced mobile broadband (eMBB) ) that may provide access for different types of devices.

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

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

Some UEs 115, such as MTC or IoT devices, may be low cost or low complexity devices and may provide for automated communication between machines (e.g., via Machine-to-Machine (M2M) communication) . M2M communication or MTC may refer to data communication technologies that allow devices to communicate with one another or a base station 105 without human intervention. In some examples, M2M communication or MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay such information to a central server or application program that makes use of the information or presents the information to humans interacting with the application program. Some UEs 115 may be designed to collect information or enable automated behavior of machines or other devices. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business charging.

Some UEs 115 may be configured to employ operating modes that reduce power consumption, such as half-duplex communications (e.g., a mode that supports one-way communication via transmission or reception, but not transmission and reception simultaneously) . In some examples, half-duplex communications may be performed at a reduced peak rate. Other power conservation techniques for the UEs 115 include entering a power saving deep sleep mode when not engaging in active communications, operating over a limited bandwidth (e.g., according to narrowband communications) , or a combination of these techniques. For example, some UEs 115 may be configured for operation using a narrowband protocol type that is associated with a defined portion or range (e.g., set of subcarriers or resource blocks (RBs) ) within a carrier, within a guard-band of a carrier, or outside of a carrier.

The wireless communications system 100 may be configured to support ultra-reliable communications or low-latency communications, or various combinations thereof. For example, the wireless communications system 100 may be configured to support ultra-reliable low-latency communications (URLLC) or mission critical communications. The UEs 115 may be designed to support ultra-reliable, low-latency, or critical functions (e.g., mission critical functions) . Ultra-reliable communications may include private communication or group communication and may be supported by one or more mission critical services such as mission critical push-to-talk (MCPTT) , mission critical video (MCVideo) , or mission critical data (MCData) . Support for mission critical functions may include prioritization of services, and mission critical services may be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, mission critical, and ultra-reliable low-latency may be used interchangeably herein.

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

In some systems, the D2D communication link 135 may be an example of a communication channel, such as a sidelink communication channel, between vehicles (e.g., UEs 115) . In some examples, vehicles may communicate using V2X communications, vehicle-to-vehicle (V2V) communications, or some combination of these. A vehicle may signal information related to traffic conditions, signal scheduling, weather, safety, emergencies, or any other information relevant to a V2X system. In some examples, vehicles in a V2X system may communicate with roadside infrastructure, such as roadside units, or with the network via one or more network nodes (e.g., base stations 105) using vehicle-to-network (V2N) communications, or with both.

The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC) or 5G core (5GC) , which may include at least one control plane entity that manages access and mobility (e.g., a mobility management entity (MME) , an access and mobility management function (AMF) ) and at least one user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW) , a Packet Data Network (PDN) gateway (P-GW) , or a user plane function (UPF) ) . The control plane entity may manage non-access stratum (NAS) functions such as mobility, authentication, and bearer management for the UEs 115 served by the base stations 105 associated with the core network 130. User IP packets may be transferred through the user plane entity, which may provide IP address allocation as well as other functions. The user plane entity may be connected to the network operators IP services 150. The operators IP services 150 may include access to the Internet, Intranet (s) , an IP Multimedia Subsystem (IMS) , or a Packet-Switched Streaming Service.

Some of the network devices, such as a base station 105, may include subcomponents such as an access network entity 140, which may be an example of an access node controller (ANC) . Each access network entity 140 may communicate with the UEs 115 through one or more other access network transmission entities 145, which may be referred to as radio heads, smart radio heads, or transmission/reception points (TRPs) . Each access network transmission entity 145 may include one or more antenna panels. In some configurations, various functions of each access network entity 140 or base station 105 may be distributed across various network devices (e.g., radio heads and ANCs) or consolidated into a single network device (e.g., a base station 105) .

The wireless communications system 100 may operate using one or more frequency bands, typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz) . Generally, the region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or decimeter band because the wavelengths range from approximately one decimeter to one meter in length. The UHF waves may be blocked or redirected by buildings and environmental features, but the waves may penetrate structures sufficiently for a macro cell to provide service to the UEs 115 located indoors. The transmission of UHF waves may be associated with smaller antennas and shorter ranges (e.g., less than 100 kilometers) compared to transmission using the smaller frequencies and longer waves of the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.

The wireless communications system 100 may also operate in a super high frequency (SHF) region using frequency bands from 3 GHz to 30 GHz, also known as the centimeter band, or in an extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz) , also known as the millimeter band. In some examples, the wireless communications system 100 may support millimeter wave (mmW) communications between the UEs 115 and the base stations 105, and EHF antennas of the respective devices may be smaller and more closely spaced than UHF antennas. In some examples, this may facilitate use of antenna arrays within a device. The propagation of EHF transmissions, however, may be subject to even greater atmospheric attenuation and shorter range than SHF or UHF transmissions. The techniques disclosed herein may be employed across transmissions that use one or more different frequency regions, and designated use of bands across these frequency regions may differ by country or regulating body.

The wireless communications system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communications system 100 may employ License Assisted Access (LAA) , LTE-Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz industrial, scientific, and medical (ISM) band. When operating in unlicensed radio frequency spectrum bands, devices such as the base stations 105 and the UEs 115 may employ carrier sensing for collision detection and avoidance. In some examples, operations in unlicensed bands may be based on a carrier aggregation configuration in conjunction with component carriers operating in a licensed band (e.g., LAA) . Operations in unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, among other examples.

A base station 105 or a UE 115 may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. The antennas of a base station 105 or a UE 115 may be located within one or more antenna arrays or antenna panels, which may support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some examples, antennas or antenna arrays associated with a base station 105 may be located in diverse geographic locations. A base station 105 may have an antenna array with a number of rows and columns of antenna ports that the base station 105 may use to support beamforming of communications with a UE 115. Likewise, a UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations. Additionally or alternatively, an antenna panel may support radio frequency beamforming for a signal transmitted via an antenna port.

The base stations 105 or the UEs 115 may use MIMO communications to exploit multipath signal propagation and increase the spectral efficiency by transmitting or receiving multiple signals via different spatial layers. Such techniques may be referred to as spatial multiplexing. The multiple signals may, for example, be transmitted by the transmitting device via different antennas or different combinations of antennas. Likewise, the multiple signals may be received by the receiving device via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords) . Different spatial layers may be associated with different antenna ports used for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO) , where multiple spatial layers are transmitted to the same receiving device, and multiple-user MIMO (MU-MIMO) , where multiple spatial layers are transmitted to multiple devices.

Beamforming, which may also be referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used at a transmitting device or a receiving device (e.g., a base station 105, a UE 115) to shape or steer an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining the signals communicated via antenna elements of an antenna array such that some signals propagating at particular orientations with respect to an antenna array experience constructive interference while others experience destructive interference. The adjustment of signals communicated via the antenna elements may include a transmitting device or a receiving device applying amplitude offsets, phase offsets, or both to signals carried via the antenna elements associated with the device. The adjustments associated with each of the antenna elements may be defined by a beamforming weight set associated with a particular orientation (e.g., with respect to the antenna array of the transmitting device or receiving device, or with respect to some other orientation) .

A base station 105 or a UE 115 may use beam sweeping techniques as part of beam forming operations. For example, a base station 105 may use multiple antennas or antenna arrays (e.g., antenna panels) to conduct beamforming operations for directional communications with a UE 115. Some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted by a base station 105 multiple times in different directions. For example, the base station 105 may transmit a signal according to different beamforming weight sets associated with different directions of transmission. Transmissions in different beam directions may be used to identify (e.g., by a transmitting device, such as a base station 105, or by a receiving device, such as a UE 115) a beam direction for later transmission or reception by the base station 105.

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

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

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

The wireless communications system 100 may be a packet-based network that operates according to a layered protocol stack. In the user plane, communications at the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based. A Radio Link Control (RLC) layer may perform packet segmentation and reassembly to communicate over logical channels. A Medium Access Control (MAC) layer may perform priority handling and multiplexing of logical channels into transport channels. The MAC layer may also use error detection techniques, error correction techniques, or both to support retransmissions at the MAC layer to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer may provide establishment, configuration, and maintenance of an RRC connection between a UE 115 and a base station 105 or a core network 130 supporting radio bearers for user plane data. At the physical layer, transport channels may be mapped to physical channels.

The UEs 115 and the base stations 105 may support retransmissions of data to increase the likelihood that data is received successfully. Hybrid automatic repeat request (HARQ) feedback is one technique for increasing the likelihood that data is received correctly over a communication link 125. HARQ may include a combination of error detection (e.g., using a cyclic redundancy check (CRC) ) , forward error correction (FEC) , and retransmission (e.g., automatic repeat request (ARQ) ) . HARQ may improve throughput at the MAC layer in poor radio conditions (e.g., low signal-to-noise conditions) . In some examples, a device may support same-slot HARQ feedback, where the device may provide HARQ feedback in a specific slot for data received in a previous symbol in the slot. In other cases, the device may provide HARQ feedback in a subsequent slot, or according to some other time interval.

In some examples, general sidelink communications (e.g., corresponding to additional or alternative use cases when compared with V2X and public safety) may use an unlicensed frequency spectrum for communications between one or more UEs 115. The communication between the UEs 115 may become congested. Thus, congestion control may be implemented at the UE 115 to reduce congestion. For example, the UE 115 may perform a channel occupancy ratio (CR) measurement or a channel busy ratio (CBR) measurement (e.g., including a sidelink received signal strength indicator (RSSI) measurement) . The channel busy measurement, such as a CBR or CR measurement, may account for an LBT failure or intra-RAT interference. However, the LBT failure and inter-RAT interference may vary from one LBT subband to another (e.g., due to channel, or channel subband, based access to Wi-Fi and potentially wideband operation in NR-U sidelink) .

Wireless communications system 100 may support the use of techniques that enable a UE 115 to perform a channel busy measurement, such as a CBR or CR measurement, for each LBT subband, which may account for LBT failure and interference at different LBT subbands among other benefits. In some examples, there may be multiple types of sidelink CR measurements. In a first type, for each LBT subband, the UE 115 may measure the total number of sub-channels used for a transmission in one or more slots and granted slots divided by the total number of configured sub-channels available for transmission which could pass LBT. A second type of sidelink CR measurement may be similar to the first type, however the UE 115 may perform the measurement for a primary LBT subband. Similarly, the UE 115 may perform a CBR measurement for each LBT subband.

In some cases, the UE 115 may schedule a sidelink message based on the results of the channel busy measurements for each LBT subband. For example, if one or more LBT subbands satisfy a CR limit associated with a CR measurement, a QoS parameter associated with the CBR measurement, or additional parameters related to the channel busy measurement for each LBT subband, the UE 115 may schedule a sidelink transmission on one or more of the LBT subbands. The UE 115 may indicate the scheduling operation to another UE 115. In some cases, the UE 115 and the other UE 115 may communicate according to the scheduling operation.

FIG. 2 illustrates an example of a wireless communications system 200 that supports channel busy measurements for sidelink communications in accordance with aspects of the present disclosure. In some examples, wireless communications system 200 may implement aspects of wireless communications system 100 and may include UE 115-a and UE 115-b, base station 105-a with coverage area 110-a, and communication link 125-a, which may be examples of UEs 115, a base station 105, and a communication link 125 described with reference to FIG. 1. As described herein, a UE 115 may perform one or more channel busy measurements 205 for LBT subbands and schedule a sidelink message based on the channel busy measurements 205, which may account for LBT failure and interference at the UE 115.

In some examples, a base station 105 may communicate with one or more UEs 115 via a communication link 125. For example, base station 105-a may communicate with UE 115-a via communication link 125-a. Additionally or alternatively, a UE 115 may communicate with additional UEs 115 via a link 210, which may be referred to as sidelink communication. For example, UE 115-a may communicate with UE 115-b via link 210 during a communication slot. The slot may include any number of symbols (e.g., OFDM symbols) and may be configured with a slot format configuration. The communication between UE 115-a, UE 115-b, and base station 105-a may become congested. Thus, a modulation coding scheme (MCS) index, a modulation coding scheme table, a number of sub-channels per transmission, a number of retransmissions, transmission power, a CR limit, or a combination may be adjusted to reduce congestions (e.g., during congestion control) .

In some cases, the UE 115 may perform a CBR measurement. The UE 115 may use the CBR as a metric for congestion control, such as during V2X communication. In some cases, such as sidelink communication, a received signal strength indicator (RSSI) measurement may be used for CBR estimation. The sidelink RSSI may be a linear average of the total received power, which may be measured in Watts (W) , observed in a configured sub-channel of a sidelink channel. For example, the total received power may be observed in OFDM symbols of a physical sidelink control channel (PSCCH) or a physical sidelink shared channel (PSSCH) (e.g., starting from the second symbol) . In some cases, the sidelink CBR measured in a slot may be the portion of sub-channels in a set of available time-frequency resources with a sidelink RSSI measurement that exceeds a configured threshold sensed over a CBR measurement window. For example, the UE 115-a may measure sidelink CBR in a slot n over a CBR measurement window [n-a, n-1] , where a is equal to 100 or 100 multiplied by 2 ^μ slots (e.g., according to a higher layer parameter timeWindowSize-CBR) .

Additionally or alternatively, the UE 115 may perform a CR measurement. The UE 115 may use the CR measurement as a metric for congestion control. For example, the UE 115 may evaluate the sidelink CR at a slot by determining the total number of sub-channels used for a transmission in a set of slots and granted in a different set of slots divided by the total number of configured sub-channels available in the transmission. That is, UE 115-a may measure sidelink CR in a slot n based on the total number of sub-channels used for the transmission in slots [n-a, n-1] and granted in slots [n, n+b] divided by the total number of configured sub-channels available in the transmission over slots [n-a, n+b] , where a and b are determined by the UE implementation (e.g., with a+b+1=1000 or 1000 multiplied by 2 ^μ slots) .

In some cases, the UE 115 may be configured with a higher layer parameter (e.g., sl-CR-Limit) and may transmit a sidelink message (e.g., a PSSCH message) in the slot n. The UE 115 may apply a limit for a priority value k, such that ∑ _i≥kCR (i) ≤CR _Limit (k) , where CR (i) is the CR evaluated in slots n through N for the sidelink transmission with a priority field in the sidelink control information (SCI) set to i, N is the congestion control processing time, and CR _Limit (k) corresponds to the higher layer parameter that is associated with the priority value k and the CBR range which includes the CBR measured in slots n through N. In some cases, the congestion control processing time N may be based on the processing capability of the UE 115 (e.g., corresponding to a first capability or a second capability) . The UE 115 may apply one of the processing time capabilities in sidelink congestion control. For example, for a first capability, the value of N may be 2, 2, 4, or 8 for a μ value of 0, 1, 2, and 3 respectively. For a second capability, the value of N may be 2, 4, 8, or 16 for a μ value of 0, 1, 2, and 3 respectively. The UE 115 may determine how to meet the limit, which may include dropping the transmission in slot n.

In some examples, general sidelink communications (e.g., corresponding to additional or alternative use cases when compared with V2X and public safety) may use an unlicensed frequency spectrum for communications between UE 115-a and UE 115-b. In some cases, when sidelink communications occur during unlicensed operation, the sidelink RSSI may include transmission from multiple RATs (e.g., from both Wi-Fi and an intra-operator UE 115) . Thus, the sidelink RSSI may not fully represent the congestion control metric on the intra-operator sidelink communications. Additionally, a portion of the total number of configured sub-channels available for transmission over [n-a, n+b] may not be available for sidelink communication. In some cases, a channel busy measurement 205, such as a CBR or CR measurement, may account for an LBT failure or intra-RAT interference. For example, the denominator for CR may be the total number of sub-channels that passed the LBT procedure. Additionally or alternatively, the multiple CBR measurements may be performed on different measurement sets to differentiate the impact due to inter-RAT interference. However, the LBT failure and inter-RAT interference may vary from one LBT subband to another (e.g., due to channel, or channel subband, based access to Wi-Fi and potentially wideband operation in NR-U sidelink) .

As described herein, wireless communications system 200 may support the use of techniques that enable a UE 115 to perform a channel busy measurement 205, such as a CBR or CR measurement, for each LBT subband, which may account for LBT failure and interference at different LBT subbands among other benefits. In some examples, there may be multiple types of sidelink CR measurements. In a first type, for each LBT subband, UE 115-a may measure the total number of sub-channels used for a transmission in one or more slots and granted slots divided by the total number of configured sub-channels available for transmission having a successful LBT. A second type of sidelink CR measurement may be similar to the first type, however UE 115-a may perform the measurement for a primary LBT subband. Similarly, UE 115-a may perform a CBR measurement for each LBT subband. The multiple types of CR measurements as well as the CBR measurement techniques are described in further detail with reference to FIG. 3.

In some cases, UE 115-a may determine a scheduling operation 215 based on the results of the channel busy measurements 205 for each LBT subband. For example, if one or more LBT subbands satisfy a CR limit associated with a CR measurement, a QoS parameter associated with the CBR measurement, or additional parameters related to the channel busy measurement 205 for each LBT subband, UE 115-a may schedule a sidelink transmission on one or more of the LBT subbands. UE 115-a may indicate the scheduling operation 215 to UE 115-b via link 210. In some cases, UE 115-a and UE 115-b may communicate according to the scheduling operation 215.

FIG. 3 illustrates an example of a channel diagram 300 that supports channel busy measurement for sidelink communications in accordance with aspects of the present disclosure. In some examples, channel 300 may implement aspects of wireless communications systems 100, wireless communications system 200, or both. Channel 300 may include one or more LBT subbands 305, which may be used for a transmitting or receiving a message (e.g., by a UE 115 or base station 105 as described with reference to FIGs. 1 and 2) . As described herein, a UE 115 may perform a channel measurement 310 (e.g., a CBR or a CR) for each LBT subband 305 in a channel to determine a scheduling operation for a transmission 315, such as a sidelink transmission.

In some examples, a UE 115 may perform a channel measurement 310 for each subband 305 over a number of slots 325 of a channel prior to a transmission 315. After the channel measurement 310, the UE 115 may process the measurement during a processing time 320. For example, the UE 115 may perform a channel measurement 310-a for subband 305-a and process the measurement during processing time 320-a. Additionally, the UE 115 may perform a channel measurement 310-b for subband 305-b and process the measurement during processing time 320-b. Although two subbands 305 are shown in channel diagram 300, the UE 115 may perform a channel measurement operation for any number of subbands 305 in a channel.

In some cases, a channel measurement 310 may include a CBR measurement, a CR measurement, or both. In some examples, there may be multiple types of sidelink CR measurements. In a first type, for each LBT subband 305, a UE 115 may measure the total number of sub-channels used for a transmission 315 in one or more slots 325 and granted slots divided by the total number of configured sub-channels available for transmission which could pass LBT. For example, the UE 115 may measure the total number of sub-channels used for its transmission in slots [n-a, n-1] and granted in slots [n, n+b] divided by the total number of configured sub-channels available in the transmission over slots [n-a, n+ b] . When a sidelink transmission 315 occurs over multiple LBT subbands 305 at the same time, the transmission 315 may be counted for each LBT subband 305 within the multiple LBT subbands 305. If the UE 115 is configured with a higher layer parameter (e.g., sl-CR-Limit) and transmits the sidelink message in a slot 325, the UE 115 may ensure a limit for a priority value for each LBT subband 305 is met. For example, the UE 115 may transmit the sidelink message in a slot n. The UE 115 may apply a limit according to the priority value k for each LBT subband j, such that ∑ _i≥kCR (i, j) ≤CR _Limit (k, j) , where CR (i, j) is the CR evaluated in slots n through N for the sidelink transmission with a priority field in the SCI set to i, N is the congestion control processing time, and CR _Limit (k, j) corresponds to the higher layer parameter that is associated with the priority value k and the CBR range which includes the CBR measured in slots n through N.

In some cases, for the first type of sidelink CR measurement, the UE 115 may determine whether to use the LBT subband 305 for a transmission 315 if a CR for the LBT subband 305 does not exceed the CR limit, as defined herein. That is, there may be independent behavior per LBT subband such that if the UE 115 determines a CR measurement for LBT subband 305-a exceeds the CR limit but a CR measurement for LBT subband 305-b does not exceed the CR limit, the UE 115 may transmit on LBT subband 305-b. Additionally or alternatively, the UE 115 may drop the transmission over the LBT subbands 305 as long as one LBT subband 305 exceeds the CR limit. For example, the UE 115 may ensure the CR limit is satisfied for both LBT subband 305-a and LBT subband 305-b. In some cases, the UE 115 may determine an average CR measurement over multiple LBT subbands 305 (e.g., LBT subband 305-a and LBT subband 305-b) and compare the average to an average CR limit, such that ∑ _i≥k∑ _jCR (i, j) ≤∑ _jCR _Limit (k, j) . If the average CR measurement exceeds the CR limit, the UE 115 may drop the transmission 315. If the average CR measurement does not exceed the CR limit, the UE 115 may use the LBT subbands (e.g., LBT subband 305-a and LBT subband 305-b) for one or more transmissions 315.

A second type of sidelink CR measurement may be similar to the first type, however the UE 115 may perform the measurement for a primary LBT subband. In some cases, the UE 115 may perform additional CR measurements on secondary LBT subbands by following the same approach as the primary LBT subband. For example, if LBT subband 305-a is a primary LBT subband and LBT subband 305-b is a secondary LBT subband, the UE 115 may perform a CR measurement for LBT subband 305-a and subsequently perform a CR measurement for LBT subband 305-b based on the results of the CR measurement for LBT subband 305-a. Additionally or alternatively, UE 115-a may perform a reduced, or simplified, measurement. For example, the CR measurement for a secondary LBT subband may use a different number of slots 325 for evaluation. In some cases, the UE 115 may not perform the CR measurement on the LBT subbands 305 (i.e., CR is zero for secondary channels) . In some cases, the UE 115 may not transmit on any LBT subband 305 if the CR measurement on the primary LBT subband exceeds the CR limit. In some other cases, the UE 115 may verify the primary LBT subband does not exceed the limit, subsequently verify each of the other LBT subbands 305 (e.g., the secondary LBT subbands) does not exceed the limit, and transmit on the subbands 305 along with the primary LBT subband if they do not exceed the limit. In some cases, the primary LBT subband may be fixed semi-statically or may be changed from one slot 325 to another (e.g., at random) .

In some examples, the channel measurement 310 may include a CBR measurement. The UE 115 may measure an RSSI for each LBT subband 305 (e.g., LBT subband 305-a and LBT subband 305-b) , which may be used for CBR estimation. The sidelink RSSI may be a linear average of the total received power, which may be measured in W, observed in a configured sub-channel of a sidelink channel. For example, the total received power may be observed in OFDM symbols of a PSCCH or a PSSCH in the LBT subband 305 (e.g., starting from the second symbol) . In some cases, for each LBT subband 305, the sidelink CBR measured in a slot 325 may be the portion of sub-channels in a set of available time-frequency resources in the LBT subband 305 with a sidelink RSSI measurement that exceeds a configured threshold for the LBT subband 305 sensed over a CBR measurement window. For example, the UE 115 may measure sidelink CBR for LBT subband 305-a or LBT subband 305-b in a slot n over a CBR measurement window [n-a, n-1] , where a is equal to 100 or 100 multiplied by 2 ^μ slots (e.g., according to a higher layer parameter timeWindowSize-CBR) .

In some cases, the configured threshold may be a preconfigured threshold and may be common across LBT subbands 305 (e.g., for LBT subband 305-a and LBT subband 305-b) or may be LBT subband 305 specific. Additionally or alternatively, the CR measurement, the MCS, the transmission power, the number of retransmissions, the number of sub-channels per transmission 315, QoS parameters associated with each CBR measurement, or a combination may be common across LBT subbands 305 (e.g., for LBT subband 305-a and LBT subband 305-b) or may vary from one LBT subband 305 to another.

In some cases, the UE 115 may transmit on an LBT subband 305 based on the corresponding QoS parameter according to the CBR measurement on the LBT subband 305. If the UE 115 transmits over multiple LBT subbands 305 (e.g., LBT subband 305-a and LBT subband 305-b) , the UE 115 may verify the QoS parameter is satisfied across the multiple LBT subbands 305. Additionally or alternatively, the UE 115 may apply a QoS parameter (e.g., the most stringent QoS parameter) across the LBT subbands 305 and transmit accordingly. For example, the UE 115 may compare the relatively higher ranked QoS parameter for one or more LBT subbands 305 to other LBT subbands 305 to determine which LBT subbands 305 to use for a transmission 315. In some cases, the UE 115 may take an average of the CBR measurement across multiple LBT subbands 305 for each channel (e.g., LBT subband 305-a and LBT subband 305-b) and may map the average CBR measurements to the average QoS parameters. In some examples, a CBR measurement for a primary LBT subband may determine the QoS parameter for other LBT subbands (e.g., secondary LBT subbands) .

FIG. 4 illustrates an example of a process flow 400 that supports channel busy measurements for sidelink communications in accordance with aspects of the present disclosure. In some examples, process flow 400 may implement aspects of wireless communication system 100, wireless communication system 200, or both. Process flow 400 includes UE 115-c and UE 115-d, which may be examples of a UEs 115 as described with reference to FIGs. 1 and 2. As descried herein, UE 115-c perform a channel busy measurement for each LBT subband in an unlicensed radio frequency spectrum band and perform a scheduling operation for sidelink communications with UE 115-d over available LBT subbands, which may allow UE 115-c and UE 115-d to communicate with reduced signaling overhead (e.g., due to interference) and latency.

At 405, UE 115-c may perform a channel busy measurement for each of a number of LBT subbands of an unlicensed radio frequency spectrum band associated with sidelink communications.

At 410, UE 115-c may determine a CR measurement for each LBT subband over a set of time resources and a total number of time resources associated with a successful LBT procedure. In some cases, UE 115-c may determine a CR measurement for a primary LBT subband of the number of LBT subbands over a set of time resources and a total number of time resources of the set of time resources associated with a successful LBT procedure. UE 115-c may determine an additional CR measurement for a secondary LBT subband of the number of LBT subbands. In some cases, the CR measurement for the secondary LBT subband may be performed via a different set of time resources compared with the CR measurement for the primary LBT subband.

At 415, UE 115-c may determine a CBR measurement for each of the number of LBT subbands over a set of time resources. In some cases, UE 115-c may determine a respective RSSI for each of the LBT subbands over the set of time resources. UE 115-c may determine the respective RSSIs for the LBT subbands exceed a respective RSSI threshold. In some examples, UE 115-c may determine the CBR measurement for a time resource based on the one or more LBT subbands. In some cases, UE 115-c may determine a set of QoS parameters associated with the sidelink message and a set of QoS parameters of an LBT subband based on the respective CBR measurement. In some examples, UE 115-c may determine an average CBR measurement for the number of LBT subbands based on respective CBR measurements for each LBT subband. For example, the average CBR measurement may be a portion of sub-channels in the one or more LBT subbands with a sidelink RSSI that exceeds a configured threshold (e.g., a preconfigured threshold) sensed over a CBR measurement window. UE 115-c may determine an average set of QoS parameters based on the average CBR measurement. In some cases, UE 115-c may determine a CBR measurement for a primary LBT subband and a set of QoS parameters for the primary LBT subband based on the CBR measurement.

At 420, UE 115-c may determine an availability of individual LBT subbands of the number of LBT subbands for sidelink communications at UE 115-c based on the channel busy measurements at 405. For example, UE 115-c may determine the individual LBT subbands are available based on respective CR measurements for each LBT subband and a CR threshold (e.g., a CR limit) for each LBT subband. In some cases, the CR threshold may be based on a priority associated with the sidelink message, where the priority may be determined by UE 115-c. In some cases, UE 115-c may determine none of the individual LBT subbands are available based on the respective CR measurements exceeding the CR threshold. In some examples, UE 115-c may determine at least one LBT subband is unavailable based on the respective CR measurement exceeding the CR threshold. In some cases, UE 115-c may determine an average CR measurement for the number of LBT subbands based on respective CR measurements for each of the number of LBT subbands.

At 430, UE 115-c may perform a scheduling operation for a sidelink message to UE 115-d based on the availability of the individual LBT subbands. In some cases, UE 115-c may schedule the sidelink message on each of the individual LBT subbands that may be available (e.g., as determined at 420) . In some other cases, UE 115-c may refrain from performing the scheduling operation based on determining none of the individual LBT subbands are available. In some examples, UE 115-c may drop the sidelink message transmission over all of the individual LBT subbands based on determining at least one LBT subband is unavailable. In some cases, UE 115-c may perform the scheduling operation for the sidelink message on the number of LBT subbands based on the average CR measurement being below a CR threshold. In some other cases, UE 115-c may perform the scheduling operation for the sidelink message on one or more LBT subbands excluding the number of LBT subbands based on the average CR measurement exceeding a CR threshold.

In some cases, the scheduling operation may depend on the CR measurements for a primary LBT subband and one or more secondary LBT subbands. UE 115-c may refrain from performing the scheduling operation for the sidelink message based on the CR measurements for the primary LBT subband and secondary LBT subbands exceeding a CR threshold. UE 115-c may perform the scheduling operation for the sidelink message on the primary LBT subband based on determining the CR measurement for the primary LBT subband is below a CR threshold. In some cases, UE 115-c may perform the scheduling operation for the sidelink message on each of the number of LBT subbands having respective CR measurements below the CR threshold. The primary LBT subband for a slot may be different from the primary LBT subband for a different slot.

In some examples, UE 115-c may perform the scheduling operation for the sidelink message on the LBT subband based on the QoS parameters of the LBT subband satisfying the QoS parameters associated with the sidelink message. In some other examples, UE 115-c may refrain from performing the scheduling operation for the sidelink message on the LBT subband based on the QoS parameters of the LBT subband failing to satisfy the QoS parameters associated with the sidelink message. In some cases, UE 115-c may refrain from performing the scheduling operation for the sidelink message on any of the number of LBT subbands based on one of the QoS parameters of the LBT subbands failing to satisfy the QoS parameters associated with the sidelink message. UE 115-c may perform the scheduling operation for the sidelink message on the number of LBT subbands based on the average set of QoS parameters satisfying the QoS parameters associated with the sidelink message. UE 115-c may perform the scheduling operation for the sidelink message on the number of LBT subbands based on the primary set of QoS parameters satisfying the QoS parameters associated with the sidelink message.

In some cases, the scheduling operation may be performed independent of an additional CBR measurement of an additional subband of the number of LBT subbands. In some examples, the primary LBT subband may be semi-statically or randomly configured for each slot of a set of time resources of the unlicensed radio frequency spectrum band.

FIG. 5 shows a block diagram 500 of a device 505 that supports channel busy measurements for sidelink communications in accordance with aspects of the present disclosure. The device 505 may be an example of aspects of a UE 115 as described herein. The device 505 may include a receiver 510, a communications manager 515, and a transmitter 520. The device 505 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 510 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to channel busy measurements for sidelink communications, etc. ) . Information may be passed on to other components of the device 505. The receiver 510 may be an example of aspects of the transceiver 820 described with reference to FIG. 8. The receiver 510 may utilize a single antenna or a set of antennas.

The communications manager 515 may perform a channel busy measurement for each of a set of LBT subbands of an unlicensed radio frequency spectrum band associated with sidelink communications, determine an availability of individual LBT subbands of the set of LBT subbands for sidelink communications at the first UE based on the respective channel busy measurement, and perform a scheduling operation for a sidelink message to a second UE based on the determined availability of individual LBT subbands of the set of LBT subbands. The communications manager 515 may be an example of aspects of the communications manager 810 described herein.

The actions performed by the communications manager 515 as described herein may be implemented to realize one or more potential advantages. One implementation may enable a UE to perform a channel busy measurement for each LBT subband of an unlicensed radio frequency spectrum band. The channel busy measurement may enable a UE to account for LBT failure and interference at different LBT subbands, which may result in higher data rates and more efficient communications (e.g., less communication errors) , among other advantages.

Based on implementing the indications as described herein, a processor of a UE or base station (e.g., a processor controlling the receiver 510, the communications manager 515, the transmitter 520, or a combination thereof) may reduce the impact or likelihood of interference in a sidelink communications system while ensuring relatively efficient communications. For example, the channel busy measurement techniques described herein may leverage a CBR measurement, a CR measurement, or both to determine a scheduling operation for a sidelink message, which may realize reduced signaling overhead (e.g., due to retransmissions) , among other benefits.

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

The communications manager 515, or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the communications manager 515, or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the communications manager 515, or its sub-components, may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

The transmitter 520 may transmit signals generated by other components of the device 505. In some examples, the transmitter 520 may be collocated with a receiver 510 in a transceiver module. For example, the transmitter 520 may be an example of aspects of the transceiver 820 described with reference to FIG. 8. The transmitter 520 may utilize a single antenna or a set of antennas.

FIG. 6 shows a block diagram 600 of a device 605 that supports channel busy measurements for sidelink communications in accordance with aspects of the present disclosure. The device 605 may be an example of aspects of a device 505, or a UE 115 as described herein. The device 605 may include a receiver 610, a communications manager 615, and a transmitter 635. The device 605 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 610 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to channel busy measurements for sidelink communications, etc. ) . Information may be passed on to other components of the device 605. The receiver 610 may be an example of aspects of the transceiver 820 described with reference to FIG. 8. The receiver 610 may utilize a single antenna or a set of antennas.

The communications manager 615 may be an example of aspects of the communications manager 515 as described herein. The communications manager 615 may include a measurement component 620, a subband availability manager 625, and a scheduler 630. The communications manager 615 may be an example of aspects of the communications manager 810 described herein.

The measurement component 620 may perform a channel busy measurement for each of a set of LBT subbands of an unlicensed radio frequency spectrum band associated with sidelink communications.

The subband availability manager 625 may determine an availability of individual LBT subbands of the set of LBT subbands for sidelink communications at the first UE based on the respective channel busy measurement.

The scheduler 630 may perform a scheduling operation for a sidelink message to a second UE based on the determined availability of individual LBT subbands of the set of LBT subbands.

The transmitter 635 may transmit signals generated by other components of the device 605. In some examples, the transmitter 635 may be collocated with a receiver 610 in a transceiver module. For example, the transmitter 635 may be an example of aspects of the transceiver 820 described with reference to FIG. 8. The transmitter 635 may utilize a single antenna or a set of antennas.

FIG. 7 shows a block diagram 700 of a communications manager 705 that supports channel busy measurements for sidelink communications in accordance with aspects of the present disclosure. The communications manager 705 may be an example of aspects of a communications manager 515, a communications manager 615, or a communications manager 810 described herein. The communications manager 705 may include a measurement component 710, a subband availability manager 715, a scheduler 720, a CR component 725, a priority manager 730, a CBR component 735, a RSSI component 740, and a QoS component 745. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses) .

The measurement component 710 may perform a channel busy measurement for each of a set of LBT subbands of an unlicensed radio frequency spectrum band associated with sidelink communications.

In some cases, the channel busy measurement includes one of a channel occupancy ratio (CR) measurement or a channel busy ratio (CBR) measurement.

The subband availability manager 715 may determine an availability of individual LBT subbands of the set of LBT subbands for sidelink communications at the first UE based on the respective channel busy measurement.

In some examples, the subband availability manager 715 may determine that one or more individual LBT subbands are available based on respective CR measurements for the one or more individual LBT subbands and a CR threshold for each of the set of LBT subbands.

In some examples, the subband availability manager 715 may determine whether one or more individual LBT subbands are available based on respective CR measurements for the one or more individual LBT subbands and the CR threshold, where the sidelink message is scheduled on each of the one or more individual LBT subbands determined to be available.

In some examples, the subband availability manager 715 may determine that none of the one or more individual LBT subbands are available based on the respective CR measurements for each of the one or more individual LBT subbands exceeding the CR threshold.

In some examples, the subband availability manager 715 may determine that at least one subband of the one or more individual LBT subbands is unavailable based on the respective CR measurement for the at least one subband exceeding the CR threshold.

The scheduler 720 may perform a scheduling operation for a sidelink message to a second UE based on the determined availability of individual LBT subbands of the set of LBT subbands.

In some examples, the scheduler 720 may refrain from performing the scheduling operation on the one or more individual LBT subbands based on determining that none of the one or more individual LBT subbands are available.

In some examples, the scheduler 720 may drop transmission of the sidelink message over all of the one or more individual LBT subbands based on determining that the at least one subband is unavailable.

In some examples, the scheduler 720 may perform the scheduling operation for the sidelink message on the set of LBT subbands based on the average CR measurement being below a CR threshold.

In some examples, the scheduler 720 may perform the scheduling operation for the sidelink message on one or more LBT subbands excluding the set of LBT subbands based on the average CR measurement exceeding a CR threshold.

In some examples, the scheduler 720 may refrain from performing the scheduling operation for the sidelink message on the set of LBT subbands based on both the first CR measurement and the second CR measurement exceeding a CR threshold.

In some examples, the scheduler 720 may perform the scheduling operation for the sidelink message on the primary subband based on determining that the first CR measurement is below a CR threshold for the primary subband.

In some examples, the scheduler 720 may perform the scheduling operation for the sidelink message on each of the set of LBT subbands having respective CR measurements below the CR threshold.

In some examples, the scheduler 720 may perform the scheduling operation for the sidelink message on the LBT subband based on the second set of QoS parameters satisfying the first set of QoS parameters.

In some examples, the scheduler 720 may refrain from performing the scheduling operation for the sidelink message on the LBT subband based on the second set of QoS parameters failing to satisfy the first set of QoS parameters.

In some examples, the scheduler 720 may refrain from performing the scheduling operation for the sidelink message on any of the set of LBT subbands based on at least one of the respective sets of QoS parameters failing to satisfy the first set of QoS parameters.

In some examples, the scheduler 720 may perform the scheduling operation for the sidelink message on the set of LBT subbands based on the average set of QoS parameters satisfying the first set of QoS parameters.

In some examples, the scheduler 720 may perform the scheduling operation for the sidelink message on the set of LBT subbands based on the primary set of QoS parameters satisfying the first set of QoS parameters.

In some cases, the scheduling operation is performed independent of a second CBR measurement of a secondary subband of the set of LBT subbands.

The CR component 725 may determine a channel occupancy ratio (CR) measurement for each of the set of LBT subbands over a set of time resources and a total number of time resources of the set of time resources associated with a successful LBT procedure.

In some examples, the CR component 725 may determine a CR threshold based on the priority associated with the sidelink message.

In some examples, the CR component 725 may determine an average CR measurement for the set of LBT subbands based on respective CR measurements for each of the set of LBT subbands.

In some examples, the CR component 725 may determine a first channel occupancy ratio (CR) measurement for a primary subband of the set of LBT subbands over a set of time resources and a total number of time resources of the set of time resources associated with a successful LBT procedure.

In some examples, the CR component 725 may determine a second CR measurement for a secondary subband of the set of LBT subbands, where the scheduling operation is performed based on the first and second CR measurements.

In some cases, the primary subband for a first slot is different from the primary subband for a second slot.

In some cases, the second CR measurement is performed via a different set of time resources compared to the first CR measurement.

The priority manager 730 may determine a priority associated with the sidelink message.

The CBR component 735 may determine a channel busy ratio (CBR) measurement for each of the set of LBT subbands over a set of time resources.

In some examples, the CBR component 735 may determine the CBR measurement for a first time resource based on the one or more LBT subbands.

In some examples, the CBR component 735 may determine an average CBR measurement for the set of LBT subbands based on respective CBR measurements for each of the set of LBT subbands.

In some examples, the CBR component 735 may determine a first channel busy ratio (CBR) measurement for a primary subband of the set of LBT subbands.

In some cases, the primary subband semi-statically or randomly configured for each slot of a set of time resources of the unlicensed radio frequency spectrum band.

The RSSI component 740 may determine a respective received signal strength indicator (RSSI) for each of the set of LBT subbands over the set of time resources.

In some examples, the RSSI component 740 may determine that the respective RSSIs for one or more LBT subbands of the set of LBT subbands exceed a respective RSSI threshold.

The QoS Component 745 may determine a first set of quality of service (QoS) parameters associated with the sidelink message.

In some examples, the QoS Component 745 may determine a second set of QoS parameters of an LBT subband of the set of LBT subbands based on a respective CBR measurement for the LBT subband.

In some examples, the QoS Component 745 may determine a respective sets of QoS parameters for the set of LBT subbands based on respective CBR measurements for the set of LBT subbands.

In some examples, the QoS Component 745 may determine an average set of QoS parameters based on the average CBR measurement.

In some examples, the QoS Component 745 may determine a primary set of QoS parameters for the primary subband based on the first CBR measurement.

FIG. 8 shows a diagram of a system 800 including a device 805 that supports channel busy measurements for sidelink communications in accordance with aspects of the present disclosure. The device 805 may be an example of or include the components of device 505, device 605, or a UE 115 as described herein. The device 805 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager 810, an I/O controller 815, a transceiver 820, an antenna 825, memory 830, and a processor 840. These components may be in electronic communication via one or more buses (e.g., bus 845) .

The communications manager 810 may perform a channel busy measurement for each of a set of LBT subbands of an unlicensed radio frequency spectrum band associated with sidelink communications, determine an availability of individual LBT subbands of the set of LBT subbands for sidelink communications at the first UE based on the respective channel busy measurement, and perform a scheduling operation for a sidelink message to a second UE based on the determined availability of individual LBT subbands of the set of LBT subbands.

The I/O controller 815 may manage input and output signals for the device 805. The I/O controller 815 may also manage peripherals not integrated into the device 805. In some cases, the I/O controller 815 may represent a physical connection or port to an external peripheral. In some cases, the I/O controller 815 may utilize an operating system such as

or another known operating system. In other cases, the I/O controller 815 may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, the I/O controller 815 may be implemented as part of a processor. In some cases, a user may interact with the device 805 via the I/O controller 815 or via hardware components controlled by the I/O controller 815.

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

In some cases, the wireless device may include a single antenna 825. However, in some cases the device may have more than one antenna 825, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory 830 may include random-access memory (RAM) and read-only memory (ROM) . The memory 830 may store computer-readable, computer-executable code 835 including instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory 830 may contain, among other things, a basic I/O system (BIOS) which may control basic hardware or software operation such as the interaction with peripheral components or devices.

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

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

FIG. 9 shows a flowchart illustrating a method 900 that supports channel busy measurements for sidelink communications in accordance with aspects of the present disclosure. The operations of method 900 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 900 may be performed by a communications manager as described with reference to FIGs. 5 through 8. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 905, the UE may perform a channel busy measurement for each of a set of LBT subbands of an unlicensed radio frequency spectrum band associated with sidelink communications. The operations of 905 may be performed according to the methods described herein. In some examples, aspects of the operations of 905 may be performed by a measurement component as described with reference to FIGs. 5 through 8.

At 910, the UE may determine an availability of individual LBT subbands of the set of LBT subbands for sidelink communications at the first UE based on the respective channel busy measurement. The operations of 910 may be performed according to the methods described herein. In some examples, aspects of the operations of 910 may be performed by a subband availability manager as described with reference to FIGs. 5 through 8.

At 915, the UE may perform a scheduling operation for a sidelink message to a second UE based on the determined availability of individual LBT subbands of the set of LBT subbands. The operations of 915 may be performed according to the methods described herein. In some examples, aspects of the operations of 915 may be performed by a scheduler as described with reference to FIGs. 5 through 8.

FIG. 10 shows a flowchart illustrating a method 1000 that supports channel busy measurements for sidelink communications in accordance with aspects of the present disclosure. The operations of method 1000 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1000 may be performed by a communications manager as described with reference to FIGs. 5 through 8. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 1005, the UE may perform a channel busy measurement for each of a set of LBT subbands of an unlicensed radio frequency spectrum band associated with sidelink communications. The operations of 1005 may be performed according to the methods described herein. In some examples, aspects of the operations of 1005 may be performed by a measurement component as described with reference to FIGs. 5 through 8.

At 1010, the UE may determine a channel occupancy ratio (CR) measurement for each of the set of LBT subbands over a set of time resources and a total number of time resources of the set of time resources associated with a successful LBT procedure. The operations of 1010 may be performed according to the methods described herein. In some examples, aspects of the operations of 1010 may be performed by a CR component as described with reference to FIGs. 5 through 8.

At 1015, the UE may determine an availability of individual LBT subbands of the set of LBT subbands for sidelink communications at the first UE based on the respective channel busy measurement. The operations of 1015 may be performed according to the methods described herein. In some examples, aspects of the operations of 1015 may be performed by a subband availability manager as described with reference to FIGs. 5 through 8.

At 1020, the UE may determine that one or more individual LBT subbands are available based on respective CR measurements for the one or more individual LBT subbands and a CR threshold for each of the set of LBT subbands. The operations of 1020 may be performed according to the methods described herein. In some examples, aspects of the operations of 1020 may be performed by a subband availability manager as described with reference to FIGs. 5 through 8.

At 1025, the UE may perform a scheduling operation for a sidelink message to a second UE based on the determined availability of individual LBT subbands of the set of LBT subbands. The operations of 1025 may be performed according to the methods described herein. In some examples, aspects of the operations of 1025 may be performed by a scheduler as described with reference to FIGs. 5 through 8.

FIG. 11 shows a flowchart illustrating a method 1100 that supports channel busy measurements for sidelink communications in accordance with aspects of the present disclosure. The operations of method 1100 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1100 may be performed by a communications manager as described with reference to FIGs. 5 through 8. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 1105, the UE may perform a channel busy measurement for each of a set of LBT subbands of an unlicensed radio frequency spectrum band associated with sidelink communications. The operations of 1105 may be performed according to the methods described herein. In some examples, aspects of the operations of 1105 may be performed by a measurement component as described with reference to FIGs. 5 through 8.

At 1110, the UE may determine a channel occupancy ratio (CR) measurement for each of the set of LBT subbands over a set of time resources and a total number of time resources of the set of time resources associated with a successful LBT procedure. The operations of 1110 may be performed according to the methods described herein. In some examples, aspects of the operations of 1110 may be performed by a CR component as described with reference to FIGs. 5 through 8.

At 1115, the UE may determine an average CR measurement for the set of LBT subbands based on respective CR measurements for each of the set of LBT subbands. The operations of 1115 may be performed according to the methods described herein. In some examples, aspects of the operations of 1115 may be performed by a CR component as described with reference to FIGs. 5 through 8.

At 1120, the UE may determine an availability of individual LBT subbands of the set of LBT subbands for sidelink communications at the first UE based on the respective channel busy measurement. The operations of 1120 may be performed according to the methods described herein. In some examples, aspects of the operations of 1120 may be performed by a subband availability manager as described with reference to FIGs. 5 through 8.

At 1125, the UE may perform the scheduling operation for the sidelink message on the set of LBT subbands based on the average CR measurement being below a CR threshold. The operations of 1125 may be performed according to the methods described herein. In some examples, aspects of the operations of 1125 may be performed by a scheduler as described with reference to FIGs. 5 through 8.

At 1130, the UE may perform a scheduling operation for a sidelink message to a second UE based on the determined availability of individual LBT subbands of the set of LBT subbands. The operations of 1130 may be performed according to the methods described herein. In some examples, aspects of the operations of 1130 may be performed by a scheduler as described with reference to FIGs. 5 through 8.

FIG. 12 shows a flowchart illustrating a method 1200 that supports channel busy measurements for sidelink communications in accordance with aspects of the present disclosure. The operations of method 1200 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1200 may be performed by a communications manager as described with reference to FIGs. 5 through 8. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 1205, the UE may perform a channel busy measurement for each of a set of LBT subbands of an unlicensed radio frequency spectrum band associated with sidelink communications. The operations of 1205 may be performed according to the methods described herein. In some examples, aspects of the operations of 1205 may be performed by a measurement component as described with reference to FIGs. 5 through 8.

At 1210, the UE may determine a channel busy ratio (CBR) measurement for each of the set of LBT subbands over a set of time resources. The operations of 1210 may be performed according to the methods described herein. In some examples, aspects of the operations of 1210 may be performed by a CBR component as described with reference to FIGs. 5 through 8.

At 1215, the UE may determine an availability of individual LBT subbands of the set of LBT subbands for sidelink communications at the first UE based on the respective channel busy measurement. The operations of 1215 may be performed according to the methods described herein. In some examples, aspects of the operations of 1215 may be performed by a subband availability manager as described with reference to FIGs. 5 through 8.

At 1220, the UE may perform a scheduling operation for a sidelink message to a second UE based on the determined availability of individual LBT subbands of the set of LBT subbands. The operations of 1220 may be performed according to the methods described herein. In some examples, aspects of the operations of 1220 may be performed by a scheduler as described with reference to FIGs. 5 through 8.

FIG. 13 shows a flowchart illustrating a method 1300 that supports channel busy measurements for sidelink communications in accordance with aspects of the present disclosure. The operations of method 1300 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1300 may be performed by a communications manager as described with reference to FIGs. 5 through 8. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 1305, the UE may perform a channel busy measurement for each of a set of LBT subbands of an unlicensed radio frequency spectrum band associated with sidelink communications. The operations of 1305 may be performed according to the methods described herein. In some examples, aspects of the operations of 1305 may be performed by a measurement component as described with reference to FIGs. 5 through 8.

At 1310, the UE may determine a channel busy ratio (CBR) measurement for each of the set of LBT subbands over a set of time resources. The operations of 1310 may be performed according to the methods described herein. In some examples, aspects of the operations of 1310 may be performed by a CBR component as described with reference to FIGs. 5 through 8.

At 1315, the UE may determine a first set of quality of service (QoS) parameters associated with the sidelink message. The operations of 1315 may be performed according to the methods described herein. In some examples, aspects of the operations of 1315 may be performed by a QoS Component as described with reference to FIGs. 5 through 8.

At 1320, the UE may determine a second set of QoS parameters of an LBT subband of the set of LBT subbands based on a respective CBR measurement for the LBT subband. The operations of 1320 may be performed according to the methods described herein. In some examples, aspects of the operations of 1320 may be performed by a QoS Component as described with reference to FIGs. 5 through 8.

At 1325, the UE may determine an availability of individual LBT subbands of the set of LBT subbands for sidelink communications at the first UE based on the respective channel busy measurement. The operations of 1325 may be performed according to the methods described herein. In some examples, aspects of the operations of 1325 may be performed by a subband availability manager as described with reference to FIGs. 5 through 8.

At 1330, the UE may perform the scheduling operation for the sidelink message on the LBT subband based on the second set of QoS parameters satisfying the first set of QoS parameters. The operations of 1330 may be performed according to the methods described herein. In some examples, aspects of the operations of 1330 may be performed by a scheduler as described with reference to FIGs. 5 through 8.

At 1335, the UE may perform a scheduling operation for a sidelink message to a second UE based on the determined availability of individual LBT subbands of the set of LBT subbands. The operations of 1335 may be performed according to the methods described herein. In some examples, aspects of the operations of 1335 may be performed by a scheduler as described with reference to FIGs. 5 through 8.

FIG. 14 shows a flowchart illustrating a method 1400 that supports channel busy measurements for sidelink communications in accordance with aspects of the present disclosure. The operations of method 1400 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 1400 may be performed by a communications manager as described with reference to FIGs. 5 through 8. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At 1405, the UE may perform a channel busy measurement for each of a set of LBT subbands of an unlicensed radio frequency spectrum band associated with sidelink communications. The operations of 1405 may be performed according to the methods described herein. In some examples, aspects of the operations of 1405 may be performed by a measurement component as described with reference to FIGs. 5 through 8.

At 1410, the UE may determine a channel busy ratio (CBR) measurement for each of the set of LBT subbands over a set of time resources. The operations of 1410 may be performed according to the methods described herein. In some examples, aspects of the operations of 1410 may be performed by a CBR component as described with reference to FIGs. 5 through 8.

At 1415, the UE may determine a first set of quality of service (QoS) parameters associated with the sidelink message. The operations of 1415 may be performed according to the methods described herein. In some examples, aspects of the operations of 1415 may be performed by a QoS Component as described with reference to FIGs. 5 through 8.

At 1420, the UE may determine a second set of QoS parameters of an LBT subband of the set of LBT subbands based on a respective CBR measurement for the LBT subband. The operations of 1420 may be performed according to the methods described herein. In some examples, aspects of the operations of 1420 may be performed by a QoS Component as described with reference to FIGs. 5 through 8.

At 1425, the UE may determine an availability of individual LBT subbands of the set of LBT subbands for sidelink communications at the first UE based on the respective channel busy measurement. The operations of 1425 may be performed according to the methods described herein. In some examples, aspects of the operations of 1425 may be performed by a subband availability manager as described with reference to FIGs. 5 through 8.

At 1430, the UE may refrain from performing the scheduling operation for the sidelink message on the LBT subband based on the second set of QoS parameters failing to satisfy the first set of QoS parameters. The operations of 1430 may be performed according to the methods described herein. In some examples, aspects of the operations of 1430 may be performed by a scheduler as described with reference to FIGs. 5 through 8.

At 1435, the UE may perform a scheduling operation for a sidelink message to a second UE based on the determined availability of individual LBT subbands of the set of LBT subbands. The operations of 1435 may be performed according to the methods described herein. In some examples, aspects of the operations of 1435 may be performed by a scheduler as described with reference to FIGs. 5 through 8.

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

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

Information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a DSP, an ASIC, a CPU, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration) .

The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.

Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media may include RAM, ROM, electrically erasable programmable ROM (EEPROM) , flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that may be used to carry or store desired program code means in the form of instructions or data structures and that may be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) , or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of computer-readable medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD) , floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of” or “one or more of” ) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C) . Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on. ”

In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label, or other subsequent reference label.

The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term “example” used herein means “serving as an example, instance, or illustration, ” and not “preferred” or “advantageous over other examples. ” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

The description herein is provided to enable a person having ordinary skill in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to a person having ordinary skill in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein, but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

A method for wireless communications at a first user equipment (UE) , comprising:

performing a channel busy measurement for each of a plurality of listen-before-talk subbands of an unlicensed radio frequency spectrum band associated with sidelink communications;

determining an availability of individual listen-before-talk subbands of the plurality of listen-before-talk subbands for sidelink communications at the first UE based at least in part on the respective channel busy measurement; and

performing a scheduling operation for a sidelink message to a second UE based at least in part on the determined availability of individual listen-before-talk subbands of the plurality of listen-before-talk subbands.
The method of claim 1, wherein performing the channel busy measurement comprises:

determining a channel occupancy ratio (CR) measurement for each of the plurality of listen-before-talk subbands over a set of time resources and a total number of time resources of the set of time resources associated with a successful listen-before-talk procedure.
The method of claim 2, wherein determining the availability of individual listen-before-talk subbands comprises:

determining that one or more individual listen-before-talk subbands are available based at least in part on respective CR measurements for the one or more individual listen-before-talk subbands and a CR threshold for each of the plurality of listen-before-talk subbands.
The method of claim 2, further comprising:

determining a priority associated with the sidelink message;

determining a CR threshold based at least in part on the priority associated with the sidelink message; and

determining whether one or more individual listen-before-talk subbands are available based at least in part on respective CR measurements for the one or more individual listen-before-talk subbands and the CR threshold, wherein the sidelink message is scheduled on each of the one or more individual listen-before-talk subbands determined to be available.
The method of claim 4, further comprising:

determining that none of the one or more individual listen-before-talk subbands are available based at least in part on the respective CR measurements for each of the one or more individual listen-before-talk subbands exceeding the CR threshold; and

refraining from performing the scheduling operation on the one or more individual listen-before-talk subbands based at least in part on determining that none of the one or more individual listen-before-talk subbands are available.
The method of claim 4, further comprising:

determining that at least one subband of the one or more individual listen-before-talk subbands is unavailable based at least in part on the respective CR measurement for the at least one subband exceeding the CR threshold; and

dropping transmission of the sidelink message over all of the one or more individual listen-before-talk subbands based at least in part on determining that the at least one subband is unavailable.
The method of claim 2, further comprising:

determining an average CR measurement for the plurality of listen-before-talk subbands based at least in part on respective CR measurements for each of the plurality of listen-before-talk subbands; and

performing the scheduling operation for the sidelink message on the plurality of listen-before-talk subbands based at least in part on the average CR measurement being below a CR threshold.
The method of claim 2, further comprising:

determining an average CR measurement for the plurality of listen-before-talk subbands based at least in part on respective CR measurements for each of the plurality of listen-before-talk subbands; and

performing the scheduling operation for the sidelink message on one or more listen-before-talk subbands excluding the plurality of listen-before-talk subbands based at least in part on the average CR measurement exceeding a CR threshold.
The method of claim 1, wherein performing the channel busy measurement comprises:

determining a first channel occupancy ratio (CR) measurement for a primary subband of the plurality of listen-before-talk subbands over a set of time resources and a total number of time resources of the set of time resources associated with a successful listen-before-talk procedure; and

determining a second CR measurement for a secondary subband of the plurality of listen-before-talk subbands, wherein the scheduling operation is performed based at least in part on the first and second CR measurements.
The method of claim 9, further comprising:

refraining from performing the scheduling operation for the sidelink message on the plurality of listen-before-talk subbands based at least in part on both the first CR measurement and the second CR measurement exceeding a CR threshold.
The method of claim 9, further comprising:

performing the scheduling operation for the sidelink message on the primary subband based at least in part on determining that the first CR measurement is below a CR threshold for the primary subband.
The method of claim 11, further comprising:

performing the scheduling operation for the sidelink message on each of the plurality of listen-before-talk subbands having respective CR measurements below the CR threshold.
The method of claim 9, wherein the primary subband for a first slot is different from the primary subband for a second slot.
The method of claim 9, wherein the second CR measurement is performed via a different set of time resources compared to the first CR measurement.
The method of claim 1, further comprising:

determining a channel busy ratio (CBR) measurement for each of the plurality of listen-before-talk subbands over a set of time resources.
The method of claim 15, wherein determining the CBR measurement comprises:

determining a respective received signal strength indicator (RSSI) for each of the plurality of listen-before-talk subbands over the set of time resources;

determining that the respective RSSIs for one or more listen-before-talk subbands of the plurality of listen-before-talk subbands exceed a respective RSSI threshold; and

determining the CBR measurement for a first time resource based at least in part on the one or more listen-before-talk subbands.
The method of claim 15, further comprising:

determining a first set of quality of service (QoS) parameters associated with the sidelink message;

determining a second set of QoS parameters of a listen-before-talk subband of the plurality of listen-before-talk subbands based at least in part on a respective CBR measurement for the listen-before-talk subband; and

performing the scheduling operation for the sidelink message on the listen-before-talk subband based at least in part on the second set of QoS parameters satisfying the first set of QoS parameters.
The method of claim 15, further comprising:

determining a first set of quality of service (QoS) parameters associated with the sidelink message;

determining a second set of QoS parameters of a listen-before-talk subband of the plurality of listen-before-talk subbands based at least in part on a respective CBR measurement for the listen-before-talk subband; and

refraining from performing the scheduling operation for the sidelink message on the listen-before-talk subband based at least in part on the second set of QoS parameters failing to satisfy the first set of QoS parameters.
The method of claim 15, further comprising:

determining a first set of quality of service (QoS) parameters associated with the sidelink message;

determining a respective sets of QoS parameters for the plurality of listen-before-talk subbands based at least in part on respective CBR measurements for the plurality of listen-before-talk subbands; and

refraining from performing the scheduling operation for the sidelink message on any of the plurality of listen-before-talk subbands based at least in part on at least one of the respective sets of QoS parameters failing to satisfy the first set of QoS parameters.
The method of claim 15, further comprising:

determining a first set of quality of service (QoS) parameters associated with the sidelink message;

determining an average CBR measurement for the plurality of listen-before-talk subbands based at least in part on respective CBR measurements for each of the plurality of listen-before-talk subbands;

determining an average set of QoS parameters based at least in part on the average CBR measurement; and

performing the scheduling operation for the sidelink message on the plurality of listen-before-talk subbands based at least in part on the average set of QoS parameters satisfying the first set of QoS parameters.
The method of claim 1, wherein:

determining a first set of quality of service (QoS) parameters associated with the sidelink message;

determining a first channel busy ratio (CBR) measurement for a primary subband of the plurality of listen-before-talk subbands;

determining a primary set of QoS parameters for the primary subband based at least in part on the first CBR measurement; and

performing the scheduling operation for the sidelink message on the plurality of listen-before-talk subbands based at least in part on the primary set of QoS parameters satisfying the first set of QoS parameters.
The method of claim 21, wherein the scheduling operation is performed independent of a second CBR measurement of a secondary subband of the plurality of listen-before-talk subbands.
The method of claim 21, wherein the primary subband for a first slot is different from the primary subband for a second slot.
The method of claim 21, wherein the primary subband is semi-statically or randomly configured for each slot of a set of time resources of the unlicensed radio frequency spectrum band.
The method of claim 1, wherein the channel busy measurement comprises one of a channel occupancy ratio (CR) measurement or a channel busy ratio (CBR) measurement.
An apparatus for wireless communications at a first user equipment (UE) , comprising:

a processor,

memory coupled with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

perform a channel busy measurement for each of a plurality of listen-before-talk subbands of an unlicensed radio frequency spectrum band associated with sidelink communications;

determine an availability of individual listen-before-talk subbands of the plurality of listen-before-talk subbands for sidelink communications at the first UE based at least in part on the respective channel busy measurement; and

perform a scheduling operation for a sidelink message to a second UE based at least in part on the determined availability of individual listen-before-talk subbands of the plurality of listen-before-talk subbands.
The apparatus of claim 26, wherein the instructions to perform the channel busy measurement are executable by the processor to cause the apparatus to:

determine a channel occupancy ratio (CR) measurement for each of the plurality of listen-before-talk subbands over a set of time resources and a total number of time resources of the set of time resources associated with a successful listen-before-talk procedure.
The apparatus of claim 27, wherein the instructions to determine the availability of individual listen-before-talk subbands are executable by the processor to cause the apparatus to:

determine that one or more individual listen-before-talk subbands are available based at least in part on respective CR measurements for the one or more individual listen-before-talk subbands and a CR threshold for each of the plurality of listen-before-talk subbands.
The apparatus of claim 27, wherein the instructions are further executable by the processor to cause the apparatus to:

determine a priority associated with the sidelink message;

determine a CR threshold based at least in part on the priority associated with the sidelink message; and

determine whether one or more individual listen-before-talk subbands are available based at least in part on respective CR measurements for the one or more individual listen-before-talk subbands and the CR threshold, wherein the sidelink message is scheduled on each of the one or more individual listen-before-talk subbands determined to be available.
The apparatus of claim 29, wherein the instructions are further executable by the processor to cause the apparatus to:

determine that none of the one or more individual listen-before-talk subbands are available based at least in part on the respective CR measurements for each of the one or more individual listen-before-talk subbands exceeding the CR threshold; and

refrain from performing the scheduling operation on the one or more individual listen-before-talk subbands based at least in part on determining that none of the one or more individual listen-before-talk subbands are available.
The apparatus of claim 29, wherein the instructions are further executable by the processor to cause the apparatus to:

determine that at least one subband of the one or more individual listen-before-talk subbands is unavailable based at least in part on the respective CR measurement for the at least one subband exceeding the CR threshold; and

drop transmission of the sidelink message over all of the one or more individual listen-before-talk subbands based at least in part on determining that the at least one subband is unavailable.
The apparatus of claim 27, wherein the instructions are further executable by the processor to cause the apparatus to:

determine an average CR measurement for the plurality of listen-before-talk subbands based at least in part on respective CR measurements for each of the plurality of listen-before-talk subbands; and

perform the scheduling operation for the sidelink message on the plurality of listen-before-talk subbands based at least in part on the average CR measurement being below a CR threshold.
The apparatus of claim 27, wherein the instructions are further executable by the processor to cause the apparatus to:

determine an average CR measurement for the plurality of listen-before-talk subbands based at least in part on respective CR measurements for each of the plurality of listen-before-talk subbands; and

perform the scheduling operation for the sidelink message on one or more listen-before-talk subbands excluding the plurality of listen-before-talk subbands based at least in part on the average CR measurement exceeding a CR threshold.
The apparatus of claim 26, wherein the instructions to perform the channel busy measurement are executable by the processor to cause the apparatus to:

determine a first channel occupancy ratio (CR) measurement for a primary subband of the plurality of listen-before-talk subbands over a set of time resources and a total number of time resources of the set of time resources associated with a successful listen-before-talk procedure; and

determine a second CR measurement for a secondary subband of the plurality of listen-before-talk subbands, wherein the scheduling operation is performed based at least in part on the first and second CR measurements.
The apparatus of claim 34, wherein the instructions are further executable by the processor to cause the apparatus to:

refrain from performing the scheduling operation for the sidelink message on the plurality of listen-before-talk subbands based at least in part on both the first CR measurement and the second CR measurement exceeding a CR threshold.
The apparatus of claim 34, wherein the instructions are further executable by the processor to cause the apparatus to:

perform the scheduling operation for the sidelink message on the primary subband based at least in part on determining that the first CR measurement is below a CR threshold for the primary subband.
The apparatus of claim 36, wherein the instructions are further executable by the processor to cause the apparatus to:

perform the scheduling operation for the sidelink message on each of the plurality of listen-before-talk subbands having respective CR measurements below the CR threshold.
The apparatus of claim 34, wherein the primary subband for a first slot is different from the primary subband for a second slot.
The apparatus of claim 34, wherein the second CR measurement is performed via a different set of time resources compared to the first CR measurement.
The apparatus of claim 26, wherein the instructions are further executable by the processor to cause the apparatus to:

determine a channel busy ratio (CBR) measurement for each of the plurality of listen-before-talk subbands over a set of time resources.
The apparatus of claim 40, wherein the instructions to determine the CBR measurement are executable by the processor to cause the apparatus to:

determine a respective received signal strength indicator (RSSI) for each of the plurality of listen-before-talk subbands over the set of time resources;

determine that the respective RSSIs for one or more listen-before-talk subbands of the plurality of listen-before-talk subbands exceed a respective RSSI threshold; and

determine the CBR measurement for a first time resource based at least in part on the one or more listen-before-talk subbands.
The apparatus of claim 40, wherein the instructions are further executable by the processor to cause the apparatus to:

determine a first set of quality of service (QoS) parameters associated with the sidelink message;

determine a second set of QoS parameters of a listen-before-talk subband of the plurality of listen-before-talk subbands based at least in part on a respective CBR measurement for the listen-before-talk subband; and

perform the scheduling operation for the sidelink message on the listen-before-talk subband based at least in part on the second set of QoS parameters satisfying the first set of QoS parameters.
The apparatus of claim 40, wherein the instructions are further executable by the processor to cause the apparatus to:

determine a first set of quality of service (QoS) parameters associated with the sidelink message;

determine a second set of QoS parameters of a listen-before-talk subband of the plurality of listen-before-talk subbands based at least in part on a respective CBR measurement for the listen-before-talk subband; and

refrain from performing the scheduling operation for the sidelink message on the listen-before-talk subband based at least in part on the second set of QoS parameters failing to satisfy the first set of QoS parameters.
The apparatus of claim 40, wherein the instructions are further executable by the processor to cause the apparatus to:

determine a first set of quality of service (QoS) parameters associated with the sidelink message;

determine a respective sets of QoS parameters for the plurality of listen-before-talk subbands based at least in part on respective CBR measurements for the plurality of listen-before-talk subbands; and

refrain from performing the scheduling operation for the sidelink message on any of the plurality of listen-before-talk subbands based at least in part on at least one of the respective sets of QoS parameters failing to satisfy the first set of QoS parameters.
The apparatus of claim 40, wherein the instructions are further executable by the processor to cause the apparatus to:

determine a first set of quality of service (QoS) parameters associated with the sidelink message;

determine an average CBR measurement for the plurality of listen-before-talk subbands based at least in part on respective CBR measurements for each of the plurality of listen-before-talk subbands;

determine an average set of QoS parameters based at least in part on the average CBR measurement; and

perform the scheduling operation for the sidelink message on the plurality of listen-before-talk subbands based at least in part on the average set of QoS parameters satisfying the first set of QoS parameters.
The apparatus of claim 26, wherein:

determine a first set of quality of service (QoS) parameters associated with the sidelink message;

determine a first channel busy ratio (CBR) measurement for a primary subband of the plurality of listen-before-talk subbands;

determine a primary set of QoS parameters for the primary subband based at least in part on the first CBR measurement; and

perform the scheduling operation for the sidelink message on the plurality of listen-before-talk subbands based at least in part on the primary set of QoS parameters satisfying the first set of QoS parameters.
The apparatus of claim 46, wherein the scheduling operation is performed independent of a second CBR measurement of a secondary subband of the plurality of listen-before-talk subbands.
The apparatus of claim 46, wherein the primary subband for a first slot is different from the primary subband for a second slot.
The apparatus of claim 46, wherein the primary subband is semi-statically or randomly configured for each slot of a set of time resources of the unlicensed radio frequency spectrum band.
The apparatus of claim 26, wherein the channel busy measurement comprises one of a channel occupancy ratio (CR) measurement or a channel busy ratio (CBR) measurement.
An apparatus for wireless communications at a first user equipment (UE) , comprising:

means for performing a channel busy measurement for each of a plurality of listen-before-talk subbands of an unlicensed radio frequency spectrum band associated with sidelink communications;

means for determining an availability of individual listen-before-talk subbands of the plurality of listen-before-talk subbands for sidelink communications at the first UE based at least in part on the respective channel busy measurement; and

means for performing a scheduling operation for a sidelink message to a second UE based at least in part on the determined availability of individual listen-before-talk subbands of the plurality of listen-before-talk subbands.
A non-transitory computer-readable medium storing code for wireless communications at a first user equipment (UE) , the code comprising instructions executable by a processor to:

perform a channel busy measurement for each of a plurality of listen-before-talk subbands of an unlicensed radio frequency spectrum band associated with sidelink communications;

determine an availability of individual listen-before-talk subbands of the plurality of listen-before-talk subbands for sidelink communications at the first UE based at least in part on the respective channel busy measurement; and

perform a scheduling operation for a sidelink message to a second UE based at least in part on the determined availability of individual listen-before-talk subbands of the plurality of listen-before-talk subbands.