Channel occupancy time sharing in unlicensed spectrum

Abstract

Wireless communication systems, apparatuses, and methods are provided. A user equipment (UE) may include a memory, a transceiver, and one or more processors coupled to the memory and the transceiver. The memory includes instructions executable by the one or more processors individually or collectively to cause the UE to perform: performing a listen before talk (LBT) procedure; acquiring a channel occupancy time (COT) based on success of the LBT procedure; transmitting a sidelink message to the second UE during the COT for notifying the second UE of the shared portion of the COT; acquiring a first transmission start point in one or more transmission start points within the remaining portion of the COT; and transmitting the side link communication within the COT after the first transmission start point is acquired.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Greek Patent Application No. 20220100803, filed on September 30, 2022, the disclosure of which is incorporated herein in its entirety as if fully set forth below and for all applicable purposes. Technical Field

[0003] Aspects of the present disclosure relate generally to wireless communication systems, and more particularly to communications within New Radio Unlicensed (NR-U) operation. Certain features may enable and provide improved communications, including channel occupancy time sharing for NR-U sidelink communications. Background Art

[0004] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcast, etc. These systems may be capable of supporting communication with multiple users by sharing available system resources (e.g., time, frequency, and power). A wireless multiple-access communication system may include multiple base stations (BSs), each of which simultaneously supports communication for multiple communication devices, which may also be referred to as user equipment (UE).

[0005] To meet the growing demand for expanded mobile broadband connectivity, wireless communication technology is evolving from LTE technology to next-generation New Radio (NR) technology. For example, compared to LTE, NR is designed to provide lower latency, higher bandwidth or throughput, and higher reliability. NR is designed to operate on a wide array of spectrum bands, for example, from low bands below about 1 gigahertz (GHz) and mid-bands from about 1 GHz to about 6 GHz to high bands such as millimeter wave (mmWave) bands. NR is also designed to operate across different spectrum types, from licensed spectrum to unlicensed spectrum and shared spectrum. Spectrum sharing enables operators to have the opportunity to aggregate spectrum to dynamically support high-bandwidth services. Spectrum sharing can extend the benefits of NR technology to operating entities that may not have access to licensed spectrum.

[0006] NR can support various deployment scenarios to benefit from various spectrums in different frequency ranges, licensed and / or unlicensed, and / or coexistence of LTE and NR technologies. For example, NR can be deployed in standalone NR mode on licensed and / or unlicensed bands, or in dual connectivity mode with various combinations of NR and LTE on licensed and / or unlicensed bands.

[0007] In a wireless communication network, a BS can communicate with a UE in both the uplink and downlink directions. Sidelink was introduced in LTE to allow a UE to transmit data to another UE (e.g., from one vehicle to another vehicle) without tunneling through the BS and / or associated core network. LTE sidelink technology has been extended to provide device-to-device (D2D) communication, vehicle-to-everything (V2X) communication, and / or cellular vehicle-to-everything (C-V2X) communication. Similarly, NR can be extended to support sidelink communication, D2D communication, V2X communication, and / or C-V2X on licensed and / or unlicensed bands (e.g., shared bands). Summary of the invention

[0008] The following summarizes some aspects of the present disclosure to provide a basic understanding of the technology discussed. This summary is not an exhaustive overview of all the expected features of the present disclosure, and is neither intended to identify the key or important elements of all aspects of the present disclosure, nor to delineate the scope of any or all aspects of the present disclosure. The sole purpose of this summary is to present some concepts of one or more aspects of the present disclosure in a summarized form as a prelude to more specific embodiments presented later.

[0009] In one aspect of the present disclosure, a method for wireless communication performed by a first sidelink user equipment (UE) may include: performing a listen-before-talk (LBT) procedure; acquiring a channel occupation time (COT) based on a success of the LBT procedure; sending COT sharing information for sharing the COT with the second UE to a second UE during the COT; acquiring a first transmission start point among one or more transmission start points within a shared portion of the COT; and sending sidelink communication within the COT after acquiring the first transmission start point.

[0010] In an additional aspect of the present disclosure, a method of wireless communication performed by a first sidelink user equipment (UE) may include: performing a listen-before-talk (LBT) procedure; acquiring a channel occupation time (COT) based on success of the LBT procedure; sending COT sharing information for sharing the COT with the second UE during the COT; sending a COT retraction signal indicating an end of sharing of the COT to the second UE during the COT; and sending sidelink communication in a remaining portion of the COT after the end of sharing of the COT.

[0011] In an additional aspect of the present disclosure, a method of wireless communication performed by a first sidelink user equipment (UE) may include: receiving a sidelink message indicating a shared channel occupation time (COT) and one or more transmission start points in the COT from a second UE; and attempting transmission of sidelink communication at a first transmission start point among the one or more transmission start points, wherein the attempted transmission is based on a reservation state of the first transmission start point.

[0012] In an additional aspect of the present disclosure, a first sidelink user equipment (UE) may include: a memory; a transceiver; and at least one processor coupled to the memory and the transceiver, wherein the first sidelink UE is configured to: perform a listen-before-talk (LBT) procedure; based on the success of the LBT procedure, obtain a channel occupancy time (COT); send COT sharing information for sharing the COT with the second UE to a second UE during the COT; obtain a first transmission start point among one or more transmission start points within a shared portion of the COT; and send sidelink communication within the COT after obtaining the first transmission start point.

[0013] In an additional aspect of the present disclosure, a first sidelink user equipment (UE) may include: a memory; a transceiver; and at least one processor coupled to the memory and the transceiver, wherein the first sidelink UE is configured to: perform a listen-before-talk (LBT) procedure; obtain a channel occupancy time (COT) based on a success of the LBT procedure; send COT sharing information for sharing the COT with the second UE during the COT; send a COT retraction signal indicating an end of sharing of the COT to the second UE during the COT; and send sidelink communication in a remaining portion of the COT after the end of sharing of the COT.

[0014] In an additional aspect of the present disclosure, a first sidelink user equipment (UE) may include: a memory; a transceiver; and at least one processor coupled to the memory and the transceiver, wherein the first sidelink UE is configured to receive a sidelink message indicating a shared channel occupation time (COT) and one or more transmission start points in the COT from a second UE; and attempt transmission of a sidelink communication at a first transmission start point among the one or more transmission start points, wherein the attempted transmission is based on a reservation state of the first transmission start point.

[0015] After reading the description of the specific exemplary embodiments of the present invention below in conjunction with the accompanying drawings, other aspects, features and examples of the present invention will become apparent to those of ordinary skill in the art. Although the features of the present invention may be discussed below with respect to certain aspects and drawings, all examples of the present invention may include one or more of the advantageous features discussed herein. In other words, although one or more examples may be discussed as having certain advantageous features, one or more of such features may also be used according to the various examples of the present invention discussed herein. In a similar manner, although the exemplary aspects may be discussed below as device, system or method examples, it should be understood that such exemplary examples may be implemented in various devices, systems and methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A wireless communication network according to some aspects of the present disclosure is illustrated.

[0017] Figure 2 An example disaggregated base station architecture is illustrated in accordance with some aspects of the present disclosure.

[0018] Figure 3 An example wireless communication network supporting channel occupancy time structure information (COT-SI) indication for NR-U sidelink operation in accordance with some aspects of the present disclosure is illustrated.

[0019] Figure 4 Example sidelink communications according to some aspects of the present disclosure are illustrated.

[0020] Figure 5 Example COT sharing between sidelink UEs according to some aspects of the present disclosure is illustrated.

[0021] Figure 6 An example of sidelink timeslots in COT sharing in unlicensed spectrum according to some aspects of the present disclosure is illustrated.

[0022] Figure 7 An example of a transmission starting point in COT sharing between sidelink UEs according to some aspects of the present disclosure is illustrated.

[0023] Figure 8 An example COT retraction signal in sidelink communications according to some aspects of the present disclosure is illustrated.

[0024] Fig.9A and Fig. 9B is a signaling diagram of example sidelink communications according to some aspects of the present disclosure.

[0025] Fig.10 is a block diagram of an exemplary user equipment (UE) according to some aspects of the present disclosure.

[0026] Fig.11 is a block diagram of an exemplary network element according to some aspects of the present disclosure.

[0027] Fig.12 is a flow chart of a communication method according to some aspects of the present disclosure.

[0028] Fig.13 is a flow chart of a communication method according to some aspects of the present disclosure.

[0029] Fig.14 is a flow chart of a communication method according to some aspects of the present disclosure. DETAILED DESCRIPTION

[0030] The detailed description set forth below in conjunction with the accompanying drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. In order to provide a comprehensive understanding of the various concepts, the specific embodiments include specific details. However, it is apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, in order to avoid obscuring such concepts, well-known structures and components are shown in block diagram form.

[0031] The present disclosure as a whole relates to wireless communication systems, which are also referred to as wireless communication networks. In various examples, techniques and devices can be used for wireless communication networks, such as code division multiple access (CDMA) networks, time division multiple access (TDMA) networks, frequency division multiple access (FDMA) networks, orthogonal FDMA (OFDMA) networks, single carrier FDMA (SC-FDMA) networks, LTE networks, GSM networks, 5th generation (5G) or new radio (NR) networks, and other communication networks. As described herein, the terms "network" and "system" can be used interchangeably.

[0032] OFDMA networks may implement radio technologies such as Evolved UTRA (E-UTRA), Institute of Electrical and Electronics Engineers (IEEE) 802.11, IEEE 802.16, IEEE 802.20, flash-OFDM, etc. UTRA, E-UTRA, and Global System for Mobile Communications (GSM) are parts of Universal Mobile Telecommunications System (UMTS). Specifically, Long Term Evolution (LTE) is a version of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS, and LTE are described in documents provided by an organization named "3rd Generation Partnership Project" (3GPP), and cdma2000 is described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). These radio technologies and standards are either known or under development. For example, the 3rd Generation Partnership Project (3GPP) is a collaboration between a group of telecommunications associations with the goal of defining globally applicable third generation (3G) mobile phone specifications. 3GPP Long Term Evolution (LTE) is a 3GPP project aimed at improving the Universal Mobile Telecommunications System (UMTS) mobile phone standard. 3GPP may define specifications for next generation mobile networks, mobile systems, and mobile devices. The present disclosure relates to the evolution from LTE, 4G, 5G, NR and beyond wireless technologies, where access to the wireless spectrum is shared between networks using a range of new and different radio access technologies or radio air interfaces.

[0033] Specifically, 5G networks consider various deployments, various spectrums, and various services and devices that can be implemented using a unified air interface based on OFDM. To achieve these goals, in addition to developing new radio technologies for 5G NR networks, further enhancements to LTE and LTE-A are also considered. 5G NR will be able to scale to (1) ultra-high density (e.g., about 1M nodes / km) 2 (1) provide coverage for the massive Internet of Things (IoT) with ultra-low complexity (e.g., on the order of tens of bits / second), ultra-low energy (e.g., on the order of 10+ years of battery life), and deep coverage with the ability to reach challenging locations; (2) provide coverage including mission-critical control with strong security to protect sensitive personal, financial, or classified information, ultra-high reliability (e.g., on the order of 99.9999% reliability), ultra-low latency (e.g., on the order of 1 millisecond), and for users with extensive mobility or lack of mobility; and (3) provide coverage with enhanced mobile broadband (including very high capacity (e.g., on the order of 10 Tbps / km 2 ), very high data rates (e.g., multi-Gbps rates, 100+Mbps user experienced rates), and deep awareness coverage with advanced discovery and optimization.

[0034] 5G NR can be implemented using an optimized OFDM-based waveform with scalable parameter sets and transmission time intervals (TTIs); with a common, flexible framework to efficiently multiplex services and features using dynamic low-latency time division duplex (TDD) / frequency division duplex (FDD) designs; and with advanced wireless technologies such as massive multiple-input multiple-output (MIMO), robust millimeter wave (mmWave) transmission, advanced channel decoding, and device-centric mobility. The scalability of parameter sets in 5G NR and the scaling of subcarrier spacing can efficiently address the operation of various services across different spectrums and different deployments. For example, in various outdoor and macro coverage deployments of less than 3GHz FDD / TDD implementations, the subcarrier spacing can appear at 15kHz on bandwidths (BWs) such as 5MHz, 10MHz, 20MHz, etc. For other various outdoor and small cell coverage deployments of TDD greater than 3GHz, the subcarrier spacing can appear at 30kHz on 80MHz / 100MHz BW. For various other indoor broadband implementations, using TDD on the unlicensed portion of the 5 GHz band, subcarrier spacing may occur at 60 kHz over 160 MHz BW. Finally, for various deployments transmitting with the mmWave component at 28 GHz TDD, subcarrier spacing may occur at 120 kHz over 500 MHz BW.

[0035] 5G NR's scalable parameter sets facilitate scalable TTIs for different latency and quality of service (QoS) requirements. For example, shorter TTIs can be used for low latency and high reliability, while longer TTIs can be used for higher spectral efficiency. Efficient multiplexing of long and short TTIs allows transmission to start on symbol boundaries. 5G NR also envisions a self-contained integrated subframe design with uplink / downlink scheduling information, data, and acknowledgment in the same subframe. The self-contained integrated subframe supports communications in unlicensed spectrum or contention-based shared spectrum, adaptive uplink / downlink, which can be flexibly configured on a per-cell basis to dynamically switch between uplink and downlink to meet current business needs.

[0036] The various other aspects and features of the present disclosure are further described below. It should be apparent that the teachings herein can be embodied in various forms, and any specific structure, function, or both disclosed herein are merely representative and not restrictive. Based on the teachings herein, it should be understood by those of ordinary skill in the art that the aspects disclosed herein can be implemented independently of any other aspects, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement a device or practice a method. In addition, such a device can be implemented or such a method can be practiced using other structures, functionality, or structures and functionality other than or different from one or more of the aspects set forth herein. For example, the method can be implemented as a part of a system, device, device, and / or as an instruction stored on a computer-readable medium for execution on a processor or computer. In addition, one aspect can include at least one element of a claim.

[0037] Deploying NR on unlicensed spectrum is called NR unlicensed (NR-U). The Federal Communications Commission (FCC) and the European Telecommunications Standards Institute (ETSI) are working to regulate 6 GHz as a new unlicensed band for wireless communications. The addition of the 6 GHz band allows hundreds of megahertz (MHz) of bandwidth (BW) to be used for unlicensed band communications. Additionally, NR-U can also be deployed on the 2.4 GHz unlicensed band, which is currently shared by various radio access technologies (RATs) such as IEEE 802.11 wireless local area networks (WLANs) or WiFi and / or license assisted access (LAA). Sidelink communications can benefit from utilizing the additional bandwidth available in unlicensed spectrum. However, channel access in a specific unlicensed spectrum may be managed by official agencies. For example, some unlicensed bands may impose restrictions on the power spectral density (PSD) and / or minimum occupied channel bandwidth (OCB) of transmissions in unlicensed bands. For example, the unlicensed national information infrastructure (UNII) radio band has a minimum OCB requirement of about at least 70%.

[0038] Some sidelink systems may operate on a 20 MHz bandwidth in an unlicensed band, e.g., for listen-before-talk (LBT) based channel access. The BS may configure a sidelink resource pool for sidelink communications on one or more 20 MHz LBT sub-bands. The sidelink resource pool is typically allocated with a plurality of frequency subchannels within a sidelink bandwidth part (SL-BWP), and the sidelink UE may select a sidelink resource (e.g., one or more subchannels in frequency and one or more time slots in time) from the sidelink resource pool for sidelink communications.

[0039] The deployment of a communication system such as a 5G New Radio (NR) system may be arranged with various components or constituent parts in a variety of ways. In a 5G NR system or network, a network node, a network entity, a mobility element of a network, a radio access network (RAN) node, a core network node, a network element or network equipment such as a base station (BS), or one or more units (or one or more components) performing base station functions may be implemented in an aggregated or decomposed architecture. For example, a BS such as a Node B (NB), an evolved NB (eNB), an NR BS, a 5G NB, an access point (AP), a transmit receive point (TRP), or a cell, etc. may be implemented as an aggregated base station (also referred to as a standalone BS or a monolithic BS) or a decomposed base station.

[0040] A converged base station may be configured to utilize a radio protocol stack that is physically or logically integrated within a single RAN node. A decomposed base station may be configured to utilize a protocol stack that is physically or logically distributed between two or more units, such as one or more central or centralized units (CUs), one or more distributed units (DUs), or one or more radio units (RUs). In some aspects, a CU may be implemented within a RAN node, and one or more DUs may be co-located with the CU, or alternatively, may be geographically or virtually distributed in one or more other RAN nodes. A DU may be implemented to communicate with one or more RUs. Each of the CU, DU, and RU may also be implemented as a virtual unit, namely a virtual central unit (VCU), a virtual distributed unit (VDU), or a virtual radio unit (VRU).

[0041] Base station type operations or network designs may take into account the aggregated nature of base station functionality. For example, a disaggregated base station may be used in an integrated access backhaul (IAB) network, an open radio access network (O-RAN (network configurations such as those initiated by the O-RAN Alliance)), or a virtualized radio access network (vRAN, also known as a cloud radio access network (C-RAN)). Disaggregation may include distributing functions across two or more units at various physical locations, as well as virtually distributing the functions of at least one unit, which may enable flexibility in network design. Various units of a disaggregated base station or disaggregated RAN architecture may be configured for wired or wireless communication with at least one other unit.

[0042] Figure 1 A wireless communication network 100 according to some aspects of the present disclosure is illustrated. The network 100 includes multiple base stations (BSs) 105 and other network entities. The BSs 105 may be stations that communicate with the UEs 115 and may also be referred to as evolved Node Bs (eNBs), next generation eNBs (gNBs), access points, etc. Each BS 105 may provide communication coverage for a particular geographic area. In 3GPP, the term "cell" may refer to that particular geographic coverage area of ​​the BS 105 and / or a BS subsystem serving that coverage area, depending on the context in which the term is used.

[0043] The BS 105 may provide communication coverage for macro cells or small cells (such as pico cells or femto cells) and / or other types of cells. A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with a service subscription with a network provider. A small cell (such as a pico cell) will generally cover a relatively small geographic area and may allow unrestricted access by UEs with a service subscription with a network provider. A small cell (such as a femto cell) will generally also cover a relatively small geographic area (e.g., a home) and, in addition to unrestricted access, may provide restricted access by UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs of users in a home, etc.). A BS for a macro cell may be referred to as a macro BS. A BS for a small cell may be referred to as a small cell BS, a pico BS, a femto BS, or a home BS. In Figure 1In the example shown, BS 105d and 105e may be conventional macro BSs, while BS 105a to 105c may be macro BSs with one of three-dimensional (3D), full-dimensional (FD), or massive MIMO capabilities. BS 105a to 105c may utilize their higher-dimensional MIMO capabilities to employ 3D beamforming in both elevation and azimuth beamforming to increase coverage and capacity. BS 105f may be a small cell BS, which may be a home node or a portable access point. BS 105 may support one or more (e.g., two, three, four, etc.) cells.

[0044] Network 100 may support synchronous operation or asynchronous operation. For synchronous operation, the BSs may have similar frame timing, and transmissions from different BSs may be approximately aligned in time. For asynchronous operation, the BSs may have different frame timing, and transmissions from different BSs may not be aligned in time.

[0045] UE 115 is dispersed throughout the wireless network 100, and each UE 115 may be stationary or mobile. UE 115 may also be referred to as a terminal, a mobile station, a subscriber unit, a station, etc. UE 115 may be a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless phone, a wireless local loop (WLL) station, etc. In one aspect, UE 115 may be a device including a universal integrated circuit card (UICC). In another aspect, UE may be a device that does not include a UICC. In some aspects, UE 115 that does not include a UICC may also be referred to as an IoT device or an Internet of Everything (IoE) device. UE 115a-115d is an example of a mobile smart phone type device that accesses the network 100. UE 115 may also be a machine that is specifically configured for connected communications (including machine type communications (MTC), enhanced MTC (eMTC), narrowband IoT (NB-IoT), etc.). UE 115e-115h are examples of various machines configured for communication to access network 100. UE 115i-115k are examples of vehicles equipped with wireless communication devices configured for communication to access network 100. UE 115 may be able to communicate with any type of BS (whether macro BS, small cell, etc.). Figure 1 , a lightning symbol (e.g., a communication link) indicates wireless transmission between a UE 115 and a serving BS 105 (which is a BS designated to serve the UE 115 on a downlink (DL) and / or uplink (UL)), desired transmission between BSs 105, backhaul transmission between BSs, or sidelink transmission between UEs 115.

[0046] In operation, BS 105a-105c uses 3D beamforming and cooperative spatial techniques (such as coordinated multi-point (CoMP) or multiple connections) to serve UEs 115a and 115b. Macro BS 105d can perform backhaul communications with BS 105a to 105c and small cell BS 105f. Macro BS 105d can also send multicast services that UEs 115c and 115d subscribe to and receive. Such multicast services may include mobile TV or streaming video, or may include other services for providing community information, such as weather emergencies or alerts, such as Amber alerts or gray alerts.

[0047] The BS 105 may also communicate with a core network. The core network may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. At least some of the BSs 105 (e.g., the BSs may be examples of evolved Node Bs (eNBs) or access node controllers (ANCs)) may interface with the core network 130 via a backhaul link (e.g., S1, S2, etc.), and may perform radio configuration and scheduling to communicate with the UE 115. In various examples, the BSs 105 may communicate with each other directly or indirectly (e.g., via a core network) via a backhaul link (e.g., X1, X2, etc.), which may be a wired communication link or a wireless communication link.

[0048] The network 100 may also support mission-critical communications with ultra-reliable and redundant links for mission-critical devices such as UE 115e, which may be a vehicle (e.g., a car, truck, bus, autonomous vehicle, airplane, ship, etc.). The redundant communication links with UE 115e may include links from macro BSs 105d and 105e, and a link from a small cell BS 105f. Other machine-type devices such as UE 115f (e.g., a thermometer), UE 115g (e.g., a smart meter), and UE 115h (e.g., a wearable device) may communicate directly with a BS (such as small cell BS 105f and macro BS 105e) through the network 100, or in a multi-hop configuration by communicating with another user device that relays its information to the network (such as UE 115f communicating temperature measurement information to smart meter UE 115g, which is then reported to the network through small cell BS 105f). In some aspects, the UE 115h may harvest energy from the surrounding environment associated with the UE 115h. The network 100 may also provide additional network efficiency through dynamic, low-latency TDD / FDD communications such as vehicle-to-vehicle (V2V) communications between the UE 115i, 115j, or 115k and other UEs 115, vehicle-to-everything (V2X) communications, cellular vehicle-to-everything (C-V2X) communications, and / or vehicle-to-infrastructure (V2I) communications between the UE 115i, 115j, or 115k and the BS 105.

[0049] In some implementations, the network 100 utilizes an OFDM-based waveform for communication. An OFDM-based system may divide the system BW into multiple (K) orthogonal subcarriers, which are also commonly referred to as subcarriers, tones, frequency bins, etc. Each subcarrier may be modulated with data. In some instances, the subcarrier spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may depend on the system BW. The system BW may also be divided into subbands. In other instances, the subcarrier spacing and / or the duration of the TTI may be scalable.

[0050] In some instances, BS 105 may assign or schedule transmission resources (e.g., in the form of time-frequency resource blocks (RBs)) for downlink (DL) transmissions and uplink (UL) transmissions in network 100. DL refers to the transmission direction from BS 105 to UE 115, and UL refers to the transmission direction from UE 115 to BS 105. The communication may be in the form of a radio frame. The radio frame may be divided into a plurality of subframes, e.g., about 10. Each subframe may be divided into time slots, e.g., about 2. Each time slot may also be divided into micro-time slots. In FDD mode, simultaneous UL transmission and DL transmission may occur in different frequency bands. For example, each subframe includes a UL subframe in a UL frequency band and a DL subframe in a DL frequency band. In TDD mode, UL transmission and DL transmission occur in different time periods using the same frequency band. For example, a subframe subset (e.g., DL subframe) in a radio frame may be used for DL ​​transmission, and another subframe subset (e.g., UL subframe) in a radio frame may be used for UL transmission.

[0051] DL subframes and UL subframes may also be divided into several zones. For example, each DL subframe or UL subframe may have a predefined zone for the transmission of reference signals, control information, and data. Reference signals are predetermined signals that facilitate communication between BS 105 and UE 115. For example, reference signals may have a specific pilot pattern or structure, wherein pilot tones may span an operational BW or frequency band, and each pilot tone is located at a predefined time and a predefined frequency. For example, BS 105 may send a cell-specific reference signal (CRS) and / or a channel state information-reference signal (CSI-RS) to enable UE 115 to estimate a DL channel. Similarly, UE 115 may send a sounding reference signal (SRS) to enable BS 105 to estimate a UL channel. Control information may include resource assignments and protocol control. Data may include protocol data and / or operational data. In some instances, BS 105 and UE 115 may communicate using self-contained subframes. Self-contained subframes may include a portion for DL ​​communication and a portion for UL communication. A self-contained subframe may be DL-centric or UL-centric. A DL-centric subframe may include a DL communication duration that is longer than a UL communication duration. A UL-centric subframe may include a UL communication duration that is longer than a UL communication duration.

[0052] In some instances, the network 100 may be an NR network deployed on a licensed spectrum. The BS 105 may transmit synchronization signals (e.g., including a primary synchronization signal (PSS) and a secondary synchronization signal (SSS)) in the network 100 to facilitate synchronization. The BS 105 may broadcast system information associated with the network 100 (e.g., including a master information block (MIB), remaining minimum system information (RMSI), and other system information (OSI)) to facilitate initial network access. In some instances, the BS 105 may broadcast the PSS, SSS, and / or MIB in the form of a synchronization signal block (SSB) on a physical broadcast channel (PBCH), and may broadcast the RMSI and / or OSI on a physical downlink shared channel (PDSCH).

[0053] Two types of channel access procedures for NR-U are available (e.g., Type 1 and Type 2). In a Type 1 channel access procedure, a wireless device (e.g., a gNB or UE) performs a channel access procedure in a duration spanned by a random number of sensing slots to determine or find an idle channel before transmitting. In a Type 2 channel access procedure, a wireless device (e.g., a gNB or UE) performs a channel access procedure in a duration spanned by a determined number of sensing slots to determine an available (e.g., idle) channel before transmitting. In some aspects, three Type 2 channel access procedures are available: Type 2A, Type 2B, and Type 2C.

[0054] In a Type 2A channel access procedure, the wireless device may transmit after sensing that the channel is available (e.g., idle) within a sensing interval of at least 25µs. In one aspect, the Type 2A channel access procedure may be used when the gap between a DL / UL transmit burst and a subsequent UL / DL transmit burst is greater than or equal to 25µs. In a Type 2B channel access procedure, the wireless device may transmit after sensing that the channel is available (e.g., idle) within a sensing interval of at least 16µs. In one aspect, the Type 2B channel access procedure may be used when the gap between a DL / UL transmit burst and a subsequent UL / DL transmit burst is greater than or equal to 16µs. Unlike Type 2A and Type 2B channel access procedures, in a Type 2C channel access procedure, the wireless device may transmit without first sensing the channel. For example, the Type 2C channel access procedure may be used when the gap between a UL / DL transmit burst and a subsequent UL / DL transmit burst is less than or equal to 16µs and the duration of the transmit burst is at most 584µs. In this case, the wireless device may omit sensing the channel before transmitting.

[0055] In some examples, a UE 115 attempting to access the network 100 may perform an initial cell search by detecting the PSS from the BS 105. The PSS may enable synchronization of period timing and may indicate a physical layer identification value. The UE 115 may then receive the SSS. The SSS may enable radio frame synchronization and may provide a cell identification value that may be combined with the physical layer identification value to identify the cell. The SSS may also enable detection of duplex mode and cyclic prefix length. The PSS and SSS may be located in the center portion of the carrier or at any suitable frequency within the carrier.

[0056] After receiving the PSS and SSS, the UE 115 may receive the MIB. The MIB may include system information for initial network access and scheduling information for RMSI and / or OSI. After decoding the MIB, the UE 115 may receive the RMSI and / or OSI. The RMSI and / or OSI may include radio resource control (RRC) information related to random access channel (RACH) procedures, paging, control resource sets (CORESET) for physical downlink control channel (PDCCH) monitoring, physical uplink control channel (PUCCH), physical uplink shared channel (PUSCH), power control, SRS, and cell barring.

[0057] After obtaining the MIB, RMSI, and / or OSI, the UE 115 may perform a random access procedure to establish a connection with the BS 105. For the random access procedure, the UE 115 may send a random access preamble, and the BS 105 may respond with a random access response. Upon receiving the random access response, the UE 115 may send a connection request to the BS 105, and the BS 105 may respond with a connection response (e.g., a contention resolution message).

[0058] After the connection is established, the UE 115 and the BS 105 may enter a normal operation phase in which operational data may be exchanged. For example, the BS 105 may schedule the UE 115 for UL communication and / or DL ​​communication. The BS 105 may send an UL scheduling grant and / or a DL scheduling grant to the UE 115 via the PDCCH. The BS 105 may send a DL communication signal to the UE 115 via the PDSCH according to the DL scheduling grant. The UE 115 may send an UL communication signal to the BS 105 via the PUSCH and / or the PUCCH according to the UL scheduling grant.

[0059] The network 100 may be designed to implement a wide range of use cases. Although in some examples, the network 100 may utilize a monolithic base station, there are a variety of other architectures that can be used to perform various aspects of the present disclosure. For example, the BS 105 may be separated into a remote radio head (RRH) and a baseband unit (BBU). The BBU may be concentrated into a BBU pool and connected to the RRH via a low-latency and high-bandwidth transmission link (such as an optical transmission link). The BBU pool may be a cloud-based resource. In some aspects, the baseband processing is performed on a virtualized server running in a data center rather than co-located with the BS 105. In another example, the base station functionality may be split between a remote unit (RU), a distributed unit (DU), and a central unit (CU). The RU typically performs low physical layer functions, while the DU performs higher layer functions, which may include higher physical layer functions. The CU performs higher RAN functions, such as radio resource control (RRC).

[0060] For simplicity of discussion, the present disclosure refers to the methods of the present disclosure being performed by a base station or more generally by a network entity, while the functionality may be performed by various architectures other than a monolithic base station. In addition to a disaggregated base station, aspects of the present disclosure may also be performed by a centralized unit (CU), a distributed unit (DU), a radio unit (RU), a near real-time (near RT) RAN intelligent controller (RIC), a non-real-time (non-RT) RIC, an integrated access and backhaul (IAB) node, a relay node, a sidelink node, etc.

[0061] In some aspects, UE 115i may perform a listen-before-talk (LBT) procedure. UE 115i may obtain a channel occupation time (COT) based on the success of the LBT procedure. UE 115i may send COT sharing information to UE 115j during the COT for sharing the COT with UE 115j.

[0062] In some cases, the LBT procedure may include the wireless node adjusting its own backoff window based on the amount of energy detected on the channel or the acknowledgement / negative acknowledgement (ACK / NACK) feedback for its own transmitted packets (as a manifestation of a collision). Generally, four categories of LBT procedures have been proposed for sensing signals on a shared channel that may indicate that the channel is occupied. In the first category (CAT 1 LBT), no LBT or CCA is applied to detect occupancy of the shared channel. The second category (CAT 2 LBT), which may also be referred to as shortened LBT, single-shot LBT or 25-µs LBT, specifies that the node performs CCA to detect energy above a predetermined threshold or to detect a message or preamble occupying the shared channel. CAT 2 LBT performs CCA without using a random backoff operation, which results in its shortened length relative to the next category.

[0063] The third category (CAT 3 LBT) performs CCA to detect energy or messages on a shared channel, but also uses random backoff and a fixed contention window. Therefore, when a node initiates CAT 3 LBT, it performs a first CCA to detect occupancy of the shared channel. If the shared channel is idle for the duration of the first CCA, the node can continue to transmit. However, if the first CCA detects a signal occupying the shared channel, the node selects a random backoff based on a fixed contention window size and performs an extended CCA. If the shared channel is detected to be idle during the extended CCA and the random number has been decremented to 0, the node can start transmitting on the shared channel. Otherwise, the node decrements the random number and performs another extended CCA. The node will continue to perform extended CCAs until the random number reaches 0. If the random number reaches 0 without any of the extended CCAs detecting channel occupancy, the node can then transmit on the shared channel. If in any of the extended CCAs, the node detects channel occupancy, the node can reselect a new random backoff based on a fixed contention window size to start the countdown again.

[0064] The fourth category (CAT 4 LBT), which may also be referred to as the full LBT procedure, performs CCA with energy or message detection using random backoff and a variable contention window size. The sequence of CCA detection proceeds similarly to the process of CAT 3 LBT, except that the contention window size is variable for the CAT 4 LBT procedure.

[0065] Figure 2 A diagram illustrating an example disaggregated base station 200 architecture is shown. The disaggregated base station 200 architecture may include one or more central units (CUs) 210 that may communicate directly with a core network 220 via a backhaul link, or indirectly with the core network 220 through one or more disaggregated base station units, such as a near real-time (near-RT) RAN intelligent controller (RIC) 225 via an E2 link, or a non-real-time (non-RT) RIC 215 associated with a service management and orchestration (SMO) framework 205, or both. The CU 210 may communicate with one or more distributed units (DUs) 230 via respective midhaul links, such as an F1 interface. The DU 230 may communicate with one or more radio units (RUs) 240 via respective fronthaul links. The RU 240 may communicate with respective UEs 115 via one or more radio frequency (RF) access links. In some implementations, a UE 115 may be served simultaneously by multiple RUs 240.

[0066] Each of the units (i.e., CU 210, DU 230, RU 240, and near-RT RIC 225, non-RT RIC 215, and SMO framework 205) may include or be coupled to one or more interfaces configured to receive or send signals, data, or information (collectively referred to as signals) via a wired or wireless transmission medium. Each of the units or an associated processor or controller that provides instructions to the communication interfaces of these units may be configured to communicate with one or more of the other units via a transmission medium. For example, these units may include a wired interface configured to receive or send signals to one or more of the other units via a wired transmission medium. Additionally, the unit may include a wireless interface that may include a receiver, transmitter, or transceiver (such as a radio frequency (RF) transceiver) configured to receive or send signals, or both, to one or more of the other units via a wireless transmission medium.

[0067] In some aspects, the CU 210 may host one or more higher layer control functions. Such control functions may include radio resource control (RRC), packet data convergence protocol (PDCP), service data adaptation protocol (SDAP), etc. Each control function may be implemented using an interface that is configured to communicate signals with other control functions hosted by the CU 210. The CU 210 may be configured to handle user plane functionality (i.e., central unit-user plane (CU-UP)), control plane functionality (i.e., central unit-control plane (CU-CP)), or a combination thereof. In some specific implementations, the CU 210 may be logically split into one or more CU-UP units and one or more CU-CP units. When implemented in an O-RAN configuration, the CU-UP unit may communicate bidirectionally with the CU-CP unit via an interface (such as an E1 interface). As needed, the CU 210 may be implemented to communicate with the DU 230 for network control and signaling.

[0068] The DU 230 may correspond to a logical unit that includes one or more base station functions for controlling the operation of one or more RUs 240. In some aspects, the DU 230 may host one or more of a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more high physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, etc.) depending at least in part on a functional split such as that defined by the Third Generation Partnership Project (3GPP). In some aspects, the DU 230 may also host one or more low PHY layers. Each layer (or module) may be implemented using an interface that is configured to communicate signals with other layers (and modules) hosted by the DU 230 or with control functions hosted by the CU 210.

[0069] The lower layer functionality may be implemented by one or more RUs 240. In some deployments, the RU 240 controlled by the DU 230 may correspond to a logical node that hosts RF processing functions or low PHY layer functions (such as performing fast Fourier transform (FFT), inverse FFT (iFFT), digital beamforming, physical random access channel (PRACH) extraction and filtering, etc.), or both, based at least in part on functional splitting (such as lower layer functional splitting). In such an architecture, the RU 240 may be implemented to handle over-the-air (OTA) communications with one or more UEs 115. In some specific implementations, real-time and non-real-time aspects of control plane and user plane communications with the RU 240 may be controlled by the corresponding DU 230. In some scenarios, this configuration may enable the implementation of the DU 230 and the CU 210 in a cloud-based RAN architecture (such as a vRAN architecture).

[0070] The SMO framework 205 may be configured to support RAN deployment and provisioning of non-virtualized network elements and virtualized network elements. For non-virtualized network elements, the SMO framework 205 may be configured to support the deployment of dedicated physical resources for RAN coverage requirements, which may be managed via an operation and maintenance interface (such as an O1 interface). For virtualized network elements, the SMO framework 205 may be configured to interact with a cloud computing platform (such as an open cloud (O-Cloud) 290) to perform network element lifecycle management (such as to instantiate virtualized network elements) via a cloud computing platform interface (such as an O2 interface). Such virtualized network elements may include, but are not limited to, CU 210, DU 230, RU 240, and near-RT RIC 225. In some specific implementations, the SMO framework 205 may communicate with hardware aspects of the 4G RAN (such as an open eNB (O-eNB) 211) via the O1 interface. Additionally, in some specific implementations, the SMO framework 205 may communicate directly with one or more RUs 240 via the O1 interface. The SMO framework 205 may also include a non-RT RIC 215 configured to support the functionality of the SMO framework 205 .

[0071] The non-RT RIC 215 may be configured to include logic functions that enable non-real-time control and optimization of RAN elements and resources, artificial intelligence / machine learning (AI / ML) workflows including model training and updating, or policy-based guidance of applications / features in the near-RT RIC 225. The non-RT RIC 215 may be coupled to or communicate with the near-RT RIC 225 (such as via an A1 interface). The near-RT RIC 225 may be configured to include logic functions that enable near-real-time control and optimization of RAN elements and resources via data collection and actions through an interface (such as via an E2 interface) that connects one or more CUs 210, one or more DUs 230, or both, and the O-eNB with the near-RT RIC 225.

[0072] In some implementations, in order to generate an AI / ML model to be deployed in the near-RT RIC 225, the non-RT RIC 215 may receive parameters or external enrichment information from an external server. Such information may be utilized by the near-RT RIC 225 and may be received from a non-network data source or from a network function at the SMO framework 205 or the non-RT RIC 215. In some examples, the non-RT RIC 215 or the near-RT RIC 225 may be configured to adjust RAN behavior or performance. For example, the non-RT RIC 215 may monitor long-term trends and patterns of performance and employ AI / ML models to perform corrective actions through the SMO framework 205 (such as via reconfiguration of O1) or via the creation of RAN management policies (such as A1 policies).

[0073] For NR-U sideline (SL) operation, SL transmissions can be quite bursty. If each UE were to perform CAT 4 LBT before initiating COT, the channel access overhead could be large and there could be high mutual blocking between these UEs. To address these issues, COT sharing between UEs has been proposed to make channel access more efficient. COT sharing between SL UEs can be achieved by the initiating UE providing COT sharing information to the additional SL UEs.

[0074] In some aspects, the first UE 115 may perform a listen-before-talk (LBT) procedure. The first UE 115 may obtain a channel occupation time (COT) based on the success of the LBT procedure. The first UE 115 may send COT sharing information to the second UE 115 during the COT for sharing the COT with the second UE 115.

[0075] In some implementations, COT structure information (COT-SI) may carry COT sharing information. In NR-U operation, downlink control information (DCI) format 2_0 has been enhanced to carry COT-SI. Such COT-SI may include time domain information, such as COT duration. If COT-SI is not present in the DCI message, the slot format indicator (SFI) may be used as the COT duration. COT-SI may also include frequency domain information identifying the frequency range of the COT. Such frequency domain information may be provided via a resource block (RB) set indicator, which may include one bit for each RB set. The level of information to be provided may be considered. For example, a UE initiating COT sharing may only provide the time and frequency domain boundaries of the COT. Alternatively, FDM and TDM sharing areas may be provided. Further, a UE initiating COT sharing may provide even more details about the COT time / frequency parameters and a description of sharable and / or non-sharable resources within the COT.

[0076] Figure 3is a block diagram of an example wireless communication system 300 that supports COT sharing information for NR-U SL operation according to one or more aspects. In some examples, the wireless communication system 300 can implement aspects of the wireless communication network 100. The wireless communication system 300 includes UE 115i and UE 115j and base station 105e. Although two UEs and one base station are illustrated, in some other specific implementations, the wireless communication system 300 may generally include multiple UEs similar to UE 115i and UE 115j, and may include more than one base station similar to base station 105e.

[0077] UE 115i and UE 115j may include various components (such as structural components, hardware components) for performing one or more functions described herein. For example, these components may include one or more processors 302 / 352 (hereinafter referred to as "processor 302" and "processor 352", respectively), one or more memory devices 304 / 354 (hereinafter referred to as "memory 304" and "memory 354", respectively), one or more transmitters 316 / 356 (hereinafter referred to as "transmitter 316" and "transmitter 356", respectively), and one or more receivers 318 / 358 (hereinafter referred to as "receiver 318" and "receiver 358", respectively). Processor 302 and processor 352 may be configured to execute instructions stored in memory 304 and memory 354, respectively, to perform the operations described herein.

[0078] As illustrated, memory 304 and memory 354 include or are configured to store information 305 / 360, LBT logic 306 / 361, COT structure scheduler 307 / 362 and COT sharing information generator 308 / 363. Memory 304 and memory 354 will include or will be configured to store additional code or information for general communication operations. According to one or more aspects described herein, the memory items identified herein are used to support COT sharing information for NR-U SL operations. For example, information 305 / 360 may include data or control information identified for either or both of the uplink transmission of base station 105e or the sideline transmission (e.g., UE 115k) to other neighboring UEs. LBT logic 306 / 361 includes code and instructions for implementing LBT capabilities at UE115i and UE 115j. Under the control of processor 302 or processor 352, respectively, UE 115i or 115j executes LBT logic 306 / 361 to enable LBT procedures (e.g., CCA, CAT 1-4 LBT, etc.). The functionality implemented and enabled by executing LBT logic 306 / 361 may be referred to herein as an "execution environment" of LBT logic 306 / 361. Utilizing operation in an NR-U network (such as wireless communication system 300), UE 115a and UE 115b may execute LBT procedures within the execution environment of LBT logic 306 / 361 to obtain COT for uplink or SL transmission.

[0079] When the execution environment of the COT structure scheduler 307 / 362 is executed under the control of the processor 302 or the processor 352, respectively, the execution environment enables the UE 115i or 115j to manage the COT obtained by the successful LBT procedure. The UE 115a or 115b may execute the COT sharing information generator 308 / 363 under the control of the associated processor 302 or the processor 352, respectively, to generate COT sharing information for communicating the structure information and sharing indicator about the current COT to the neighboring UE for SL communication (e.g., SL transmission from UE 115j to UE 115i, or SL transmission from UE 115i to UE 115j).

[0080] Transmitter 316 and transmitter 356 are configured to transmit reference signals, control information, and data to one or more other devices (such as to base station 105e via uplink transmission or to another UE (e.g., UE 115j or UE 115i) via SL transmission), and receiver 318 and receiver 358 are configured to receive reference signals, synchronization signals, control information, and data from one or more other devices. For example, transmitter 316 may transmit signaling, control information, and data to base station 105e or UE 115j, and receiver 318 may receive signaling, control information, and data from base station 105e or UE 115j. In some implementations, transmitter 316 and receiver 318 may be integrated into one or more transceivers.

[0081] According to one aspect of the present disclosure, the UE 115i may successfully establish a COT on a shared communication spectrum of the wireless communication network 300 after detecting a successful LBT procedure executed within the execution environment of the LBT logic 306. The UE 115i may then determine the duration of the current COT and the time-frequency resource boundaries of the COT within the execution environment of the COT structure scheduler 307. Such time-frequency resources may be indicated via a set of resource blocks (RBs) for the COT identified by a bitmap, wherein each bit identifies an RB in the set. Having determined the structure information about the current COT, the UE 115i may generate COT sharing information within the execution environment of the COT sharing information generator 308, the COT sharing information including the remaining COT duration and the time-frequency resources of the current COT. The UE 115i may then use the transmitter 316 to send the COT sharing information (e.g., SL message 380) for SL transmission.

[0082] In some implementations, the COT sharing information may be sent in the COT-SI. In one example implementation, the UE 115i may instruct the transmitter 316 to piggyback the COT sharing information with other transmissions in a unicast, multicast, or broadcast type transmission, such as as part of the sidelink control information 1 (SCI-1) or the sidelink control information 2 (SCI-2). Current standards specify that all UEs may have the ability to decode information in both SCI formats (SCI-1 and SCI-2). Alternatively, the UE 115i may instruct the transmitter 316 to send the COT sharing information separately in a dedicated transmission, for example, within the SCI-2 or within a physical sidelink shared channel (PSSCH) communication, a physical sidelink control channel (PSCCH) communication, and / or other suitable communications. The UE 115j may receive the SL message 380 including the COT sharing message via the receiver 358 and know that it may share transmission resources with the COT initiated by the UE 115i.

[0083] It should be noted that while the previous description of COT establishment and communication of COT sharing information to neighboring UEs is described with respect to UE 115i as a COT initiating UE, various aspects may also be implemented by other neighboring UEs, such as UE 115j. In such an alternative example, UE 115j will establish a COT and communicate COT sharing information to UE 115i in a similar manner, such as via SL message 390.

[0084] It should be further noted that SL communication capabilities (such as the SL communication capabilities of UE 115i and UE 115j) can be configured as autonomous capabilities so that when the environment in which UE 115i and UE 115j are located supports SL communication, UE 115i and UE 115j can autonomously choose to perform SL communication. Additional aspects can provide SL communication capabilities that are controlled by the network, such as via an enabling signal sent from base station 105e. In such additional aspects, base station 105e can determine whether the current environment will support or benefit from UE SL communication, and in response to the determination, signal a SL communication enabling signal to either or both of UE 115i and UE 115j.

[0085] Figure 4 4 is a diagram illustrating an example 400 of SL communication between UE 115i and UE 115j according to various aspects of the present disclosure. Figure 4As shown in , UE 115i may communicate with UE 115j (and one or more other UEs 115) via one or more SL channels 410. In some aspects, UE 115i and UE 115j may use one or more SL channels 410 to communicate for P2P communication, D2D communication, V2X communication (e.g., may include V2V communication, V2I communication, V2P communication, V2N communication, etc.), mesh network, etc. In some aspects, UE 115i and UE 115j may correspond to one or more other UEs described elsewhere herein, such as UE 115k. In some aspects, one or more SL channels 410 may use a PC5 interface and / or may operate in a high frequency band (e.g., a 5.9 GHz band). For example, in a first mode (sometimes referred to as mode 1, etc.), a base station (e.g., base station 105e) may allocate resources for one or more SL channels 410, may provide a dynamic grant or activate a configured SL grant for SL communication, may receive SL feedback reported by a sending UE, etc. Additionally or alternatively, in a second mode (sometimes referred to as Mode 2 and / or similar modes), UE 115i and UE 115j may autonomously select SL resources for one or more SL channels 410, and SL communications may be scheduled using sidelink control information (SCI). Additionally or alternatively, in some cases, UE 115i and UE 115j may synchronize the timing of a transmit time interval (TTI) (e.g., frame, subframe, time slot, symbol, etc.) using global navigation satellite system (GNSS) timing.

[0086] As in Figure 4As further shown in FIG. 1 , one or more SL channels 410 may include a physical sidelink control channel (PSCCH) 415, a physical sidelink shared channel (PSSCH) 420, a physical sidelink feedback channel (PSFCH) 425, and the like. The PSCCH 415 may be used to transmit control information, similar to a physical downlink control channel (PDCCH) and / or a physical uplink control channel (PUCCH) used for cellular communication with the base station 105e via an access link or access channel. The PSSCH 420 may be used to transmit data, similar to a physical downlink shared channel (PDSCH) and / or a physical uplink shared channel (PUSCH) used for cellular communication with the base station 105e via an access link or access channel. For example, the PSCCH 415 may carry an SCI 430, which may indicate various control information for sidelink communication, such as one or more resources (e.g., time resources, frequency resources, space resources, etc.), wherein a transport block (TB) 435 may be carried on the PSSCH 420. The TB 435 may include data. The PSFCH 425 may be used to convey SL feedback 440 , such as hybrid automatic repeat request (HARQ) feedback (eg, acknowledgement or negative acknowledgement (ACK / NACK) information), transmit power control (TPC), scheduling request (SR), and the like.

[0087] In some aspects, one or more SL channels 410 may use a resource pool. For example, a scheduling assignment (e.g., included in SCI 430) may be sent in a subchannel using specific resource blocks (RBs) across time. In some aspects, data transmissions associated with the scheduling assignment (e.g., on PSSCH 420) may occupy adjacent RBs in the same subframe as the scheduling assignment (e.g., using frequency division multiplexing). In some aspects, the scheduling assignment and the associated data transmission are not sent on adjacent RBs.

[0088] In some aspects, UE 115 (e.g., UE 115i or UE 115j) may operate using a transmission mode in which resource selection and / or scheduling is performed by UE 115 (e.g., rather than base station 105e). In some aspects, UE 115 may perform resource selection and / or scheduling by sensing channel availability for transmission. For example, UE 115 may measure received signal strength indicator (RSSI) parameters associated with various SL channels (e.g., SL-RSSI (S-RSSI) parameters), may measure reference signal received power (RSRP) parameters associated with various SL channels (e.g., PSSCH-RSRP parameters), may measure reference signal received quality (RSRQ) parameters associated with various SL channels (e.g., PSSCH-RSRQ parameters), etc., and may select a channel for transmission of SL communications based at least in part on these measurements.

[0089] Additionally or alternatively, the UE 115 may perform resource selection and / or scheduling using the SCI 430 (which may indicate occupied resources, channel parameters, etc.) received in the PSCCH 415. Additionally or alternatively, the UE 115 may perform resource selection and / or scheduling by determining a channel busy rate (CBR) associated with various SL channels, which may be used for rate control (e.g., by indicating a maximum number of resource blocks that the UE 115 may use for a particular subframe set).

[0090] In a transmission mode in which resource selection and / or scheduling is performed by the UE 115, the UE 115 may generate a SL grant in the COT shared information and may transmit the grant in the SCI 330. The SL grant may indicate, for example, one or more parameters (e.g., transmission parameters) to be used for an upcoming SL transmission, such as one or more resource blocks (e.g., for TB 435) to be used for an upcoming SL transmission on the PSSCH 420, one or more subframes to be used for the upcoming SL transmission, a modulation and coding scheme (MCS) to be used for the upcoming SL transmission, etc. In some aspects, the UE 115 may generate a SL grant that indicates one or more parameters for semi-persistent scheduling (SPS), such as the periodicity of the SL transmission. Additionally or alternatively, the UE 115 may generate a SL grant for event-driven scheduling (such as for an on-demand SL message).

[0091] Figure 5 is a diagram illustrating a wireless communication system 500 having UEs (e.g., UE 115i, UE 115j, and UE 115k) for NR-U SL operation according to various aspects of the present disclosure. In some examples, the wireless communication system 500 may implement various aspects of the wireless communication network 100. After performing a successful LBT procedure or other clear channel assessment (CCA), UE 115i may acquire a COT within an unlicensed (e.g., shared) spectrum of the wireless communication system 500, and transmit COT sharing information to other UEs to share the acquired COT. UE 115i may be represented as a COT initiator (or initiating UE), and other UEs (e.g., UE 115j and UE 115k) may be represented as COT responders (or responding UEs).

[0092] In some instances, the UE 115i may perform an LBT procedure 502 (or other CCA) to gain access to a COT in an unlicensed (e.g., shared) spectrum. For example, the UE 115i may perform a Category 1 LBT, a Category 2 LBT, a Category 3 LBT, and / or a Category 4 LBT to gain access to a COT 504 in an unlicensed spectrum. In some aspects, the UE 115i may perform LBT in one or more time resources, space resources, and / or frequency resources. These frequency resources may include a spectrum, a frequency band, a frequency subband, a frequency subchannel, a resource element, a resource block, and / or a frequency interlace. These time resources may include a time slot, a subslot, a symbol, a subframe, or any other suitable time resource. In some aspects, the UE 115i may perform LBT for one or more directional beams (e.g., a beam in the direction of a UE to which the UE 115i intends to send communications and / or from which it intends to receive communications).

[0093] UE 115i may acquire COT 504 based on the success of LBT procedure 502. UE 115i may acquire COT 504 to send SL communication to another UE (or multiple UEs). Additionally or alternatively, UE 115i may share COT 504 with other UEs. Therefore, the total channel occupancy time may be divided into an initial time period during which the initiating UE may perform a transmission, which may include COT sharing information indicating when the initial transmission ends, the remaining duration of the channel occupancy time available for sharing, etc. One or more responding UEs may monitor the COT sharing information sent by other UEs (e.g., the initiating UE) to recover the COT sharing information that can be used to perform transmission during the time period corresponding to the shared channel occupancy time.

[0094] The COT sharing information may include a COT resource allocation indicating resources that the responding UE may use to share the COT. In some aspects, the initiating UE may send the COT sharing information to the responding UE and other UEs (e.g., a group of UEs, a set of UEs). The initiating UE may send the COT sharing information including the resource allocation to the set of UEs to share the COT with the set of UEs.

[0095] In some aspects, the initiating UE may send the COT sharing information via sidelink control information (e.g., SCI-1, SCI-2), an RRC message, a PSCCH message, a PSSCH message, or other suitable communication. For example, the initiating UE may send the COT sharing information in the SL_COT_SharingInformation field via sidelink control information 2 (SCI-2).

[0096] In some aspects, the COT sharing information may include information (e.g., parameters, resources, settings, commands, etc.) that enables the initiating UE to share the COT with other UEs. Sharing the COT with other UEs may enable other UEs to send and / or receive communications during the COT in an efficient and coordinated manner. In some aspects, the COT sharing information may include an identifier associated with a set of UEs that share the COT. The identifier may include a unique layer 1 identifier for each UE sharing the COT. In some aspects, the COT sharing information may indicate the type of channel access procedure associated with the COT. For example, the COT sharing information may indicate whether the COT is associated with a type 2A channel access procedure, a type 2B channel access procedure, or a type 2C channel access procedure.

[0097] In some aspects, the COT sharing information may include time resource allocations associated with COT sharing. For example, the time resource allocation may include a COT start time, a COT end time, and / or a COT duration. The time resource allocation may include time resources (e.g., time slots, sub-time slots, symbols, frames, etc.) allocated to the set of UEs sharing the COT. For example, the time resource allocation may indicate an index indicating the starting time slot and / or sub-time slot allocated to the set of UEs. The time resource allocation may indicate the number of time resources (e.g., the number of time slots, sub-time slots, and / or symbols) allocated to the set of UEs. For example, the time resource allocation may indicate that time slot 1 is allocated to the initiating UE, time slot 2 is allocated to the responding UE, and time slot 3 is allocated to another responding UE. The initiating UE may indicate the time resource allocation to the responding UEs sharing the COT in a time domain resource allocation (TDRA) via SCI-1.

[0098] In some aspects, the COT sharing information may include frequency resource allocations (e.g., frequency ranges) associated with the COT sharing. For example, the frequency resource allocations may include a starting frequency (e.g., a starting frequency subchannel index, a starting frequency band, a starting frequency interlace). The frequency resource allocations may include an ending frequency (e.g., an ending subchannel, an ending frequency band). The frequency resource allocations may include a frequency interlace (e.g., a frequency interlace index, an index of a subchannel). The frequency resource allocations may indicate frequency resources allocated to a set of UEs that share the COT with the initiating UE. The initiating UE may indicate the frequency resource allocations to the responding UEs that share the COT in a frequency domain resource allocation (FDRA) via SCI-1.

[0099] In some aspects, the initiating UE may send a flag indicating that the initiating UE is sharing the COT. In this regard, the initiating UE may send a flag via an SCI (e.g., SCI-1, SCI-2) indicating that the initiating UE is sharing the COT. The flag may include a single-bit (e.g., 0 or 1) indicator, a multi-bit indicator, a code point, or other indicators indicating that other UEs (e.g., a responding UE that receives the flag) can share the COT.

[0100] In some aspects, the initiating UE may send the flag in the SCI-2 via the PSSCH. The SCI-2 may include a destination identifier associated with the responding UE and other UEs, indicating that the initiating UE shares the COT with the responding UE and other UEs. If the SCI-2 includes an identifier that matches an identifier associated with the receiving UE, a UE that receives and decodes the SCI-2 near the initiating UE may share the COT with the initiating UE.

[0101] In some aspects, the COT sharing information may indicate a groupcast identifier associated with a set of UEs for sharing the COT with the initiating UE. In this regard, the initiating UE may send the COT sharing information via SCI-2. The SCI-2 may include a groupcast identifier indicating a set of UEs that may share the COT.

[0102] Still refer to Figure 5 According to the illustrated aspect, UE 115i may send COT sharing information via COT-SI. When generating COT-SI 505a, UE 115i may determine the time and frequency resources (t×f) that define COT 504, and may also determine the time and frequency resource set that defines the reserved resource set (such as reserved resource region 507a). UE 115i may then send COT-SI 505a to neighboring UEs (such as UE 115j and UE 115k) via SL message 503. COT-SI 505a will include the remaining duration of COT 504, the time and frequency resources (t×f) that define COT 504, and the time and frequency resource set that defines the reserved resource region 507a.

[0103] By including a time-frequency resource set defining a reserved resource region 507a, UE 115i provides additional information defining a shareable COT region within COT 504 to UE 115j and UE 115k. A shareable COT region may also include a shareable TDM region and / or a shareable FDM region. Other UEs (such as UE 115j and 115k) may perform TDM sharing in a shareable TDM region and perform FDM sharing in a shareable FDM region. UE 115j and UE 115k will also know that the reserved resource region 507a is not shareable, and thus, UE 115j and UE 115k will not attempt to access a shared communication spectrum within COT 504 that falls within the reserved resource region 507a. This enhanced design may take advantage of the burst nature of these transmissions, for example, for enhanced mobile broadband (eMBB) services.

[0104] The current mechanism defined for SCI-1 messaging allows the initiating UE to allocate additional additional time slots within a specific time slot range of the current COT, and these two future time slots are reserved for initiating UE communications and cannot be shared with neighboring UEs. After successfully acquiring COT 504 using a successful LBT procedure 502, UE 115i can generate COT-SI 505a to include not only the remaining duration of COT 504 and the time and frequency resources of COT 504, but also the identification of additional reserved resource areas 507b and 507c, as indicated by arrows 509 and 511. Reserved resource areas 507b and 507c are reserved for SL communications of UE 115i and cannot be shared by other UEs including UE 115j and UE 115k. UE 115i will transmit such COT-SI 505a to UE 115j and UE115k via SL message 503.

[0105] Additionally or alternatively, UE 115i may generate a second COT-SI 505b that indicates that the remaining duration of COT 504 becomes sharable. For example, COT-SI 505a may determine the time and frequency resources (t×f) that define COT 504, but may not further indicate when COT 504 will become sharable. On the other hand, COT-SI 505b may provide additional information to UE 115j and UE 115k that defines a sharable COT region (or shared COT) within COT 504. For example, COT-SI 505b may be located at the end of reserved resource region 507a and used as a marker to indicate the starting point of the shared COT. UE 115j and UE 115k that receive and decode COT-SI 505b in proximity to UE 115i may know that the remainder of COT 504 is now sharable, and may acquire time slots in the shared COT (such as in sharable resource regions 513, 515, and 517) to transmit SL communications to UE 1. COT-SI 505b may also provide other structural information for COT 504. For example, identification of reserved resource regions 507b and 507c may be provided by COT-SI 505b in addition to or in lieu of COT-SI 505a.

[0106] In some aspects, UE 115j and UE 115k compete for access to the sharable channel occupancy time. According to the illustrated example, UE 115j may perform an LBT procedure and acquire a sharable area 513 to send SL communications to UE 115i after the LBT procedure is successful, UE 115k may perform an LBT procedure and acquire a sharable area 515 to send SL communications to UE 115i after the LBT procedure is successful, and UE 115k may perform another LBT procedure and acquire another sharable area 517 to send SL communications to UE 115i after the LBT procedure is successful. UE 115i may send SL communications to UE 115k in a reserved area 507b reserved for UE 115i, and send SL communications to UE 115j in a reserved area 507c reserved for UE 115i.

[0107] In the context of a COT sharing information that identifies a particular resource as sharable in response to a UE detecting it, the network may provide that the assumption that the resource is sharable will always be valid. Enforced consistency may provide a more restrictive aspect in which the sharable or non-sharable status of a resource identified for a particular COT will not change. However, if the initiating UE changes its mind or encounters a change in communication (e.g., if a high priority traffic with a packet delay budget (PDB) occurs) and wants to use the previously indicated sharable resources, the initiating UE may want to send in the previously shared COT and / or reclaim the previously shared COT for its own use.

[0108] In some aspects, based on the COT sharing information, the initiating UE may have some information about when to resume transmission in the previously indicated sharable resources. For example, if the COT sharing information grants access to a single responding UE and indicates a type 2C channel access procedure, then when the initiating UE receives a response from the responding UE, the initiating UE will know that the duration of the transmission is at most 584 us. The initiating UE can therefore predict the end of the response. However, in most cases, there may be more flexibility in the type of channel access procedure, and one or more responding UEs may attempt to transmit a response in the shared COT, which makes it difficult for the initiating UE to predict the end of the response.

[0109] Still refer to Figure 5In the illustrated aspect, in the shared COT, there may be multiple gaps between responses from UEs (e.g., gaps between resource regions 507a, 513, 515, 507b, 517, and 507c). Therefore, the UE (the initiating UE or the responding UE) may resume transmission one or more times during the shared COT based on the duration of the gap with the reference transmission by performing a channel access procedure such as a type 2 channel access procedure. For example, the initiating UE (or the responding UE) may attempt to transmit at a transmission start point (TSP), where the type of channel access procedure is based on the duration of the gap between the attempted TSP and the reference transmission. In some aspects, the reference transmission is the end of the most recent transmission from the initiating UE before the shared COT (e.g., the end of the reserved resource region 507a). In some aspects, the reference transmission is the end of the most recent transmission of the initiating UE (e.g., the end of the most recently occurring resource region 507a, 507b, or 507c). In some aspects, the reference transmission is in response to the end of the most recent transmission of the initiating UE. For example, if the initiating UE is included in the destination of the transmission (e.g., the initiating UE is listed in the destination identification in SCI-2), the transmission is considered to be in response to the transmission of the initiating UE. As another example, if the responding UE is an eligible responder of the COT (e.g., the responding UE is listed in the group for COT sharing indicated in the COT sharing information), the transmission from the responding UE is considered to be in response to the transmission of the initiating UE. In the illustrated aspect, the responding UE 115j transmits to the initiating UE 115i at the resource area 513, the responding UE 115k transmits to the initiating UE 115i at the resource area 515, and the responding UE 115k transmits to the initiating UE 115i at the resource area 517, and each of these transmissions is defined as being in response to the transmission of the initiating UE. Therefore, the reference transmission can be the end of one of the resource areas 513, 515, or 517 that occurred most recently.

[0110] In some implementations, the initiating UE will compete with the responding UE for access to the sharable resources. Figure 5In the aspects illustrated in , UE 115i sends COT-SI 505b that identifies the remaining duration of COT 504 as a sharable resource. UE 115i subsequently encounters some changes in the communication, such as high priority traffic with a packet delay budget (PDB) appearing, which determines to attempt to transmit within the previously indicated sharable region. However, since UE 115i did not initially schedule the sharable area as a reserved area (such as reserved resource areas 507a, 507b, and 507c), before UE 115i can attempt SL communication within the shared COT, it will perform LBT procedures to compete with other neighboring UEs (such as UE 115j and UE 115k) for access to the shared communication spectrum. In other words, there will be no additional protection for the initiating UE (UE 115i) to use the sharable resources in its own COT (COT 504), even if UE 115i is still allowed to share the use of the sharable resources. In this case, UE 115i will act as its own responding device.

[0111] In some implementations, the initiating UE may be given priority to acquire a TSP for retransmissions within the sharable region. The TSP may correspond to the beginning of a portion of the COT that may be used by the initiating UE for retransmissions in resources shared with other UEs.

[0112] For example, Figure 6 As shown in , the SL slot structure 605 without a physical sidelink feedback channel (PSFCH) may include a total of fourteen (14) symbols, of which thirteen (13) symbols indexed from zero (0) to twelve (12) may be used for physical sidelink control channel (PSCCH) and / or physical sidelink shared channel (PSSCH) transmission, and the last symbol in the slot (index thirteen (13)) is left as a gap during which no transmission is performed. In addition, as Figure 6 As shown in , the first symbol is used for AGC training, whereby the second symbol (symbol 1) is a repetition of the first symbol (symbol 0) to increase the reliability of PSCCH and / or PSSCH transmission (for example, because the receiving UE may not be able to correctly receive and / or decode the first symbol before performing AGC training). Alternatively, the SL time slot structure 610 with PSFCH may include a total of fourteen (14) symbols, of which ten (10) symbols indexed from zero (0) to nine (9) may be used for PSCCH and / or PSSCH transmission, two symbols indexed eleven (11) and twelve (12) are used for repetition of PSFCH symbols, and two symbols indexed ten (10) and thirteen (13) are left as gaps between which no transmission is performed. Regardless of whether the SL time slot structure includes PSFCH symbols, the last symbol in the time slot is a gap symbol, and the first symbol in the time slot is an automatic gain control (AGC) symbol, which is a repetition of the second symbol.

[0113] Thus, in some aspects, a UE (an initiating UE or a responding UE) may determine an attempted TSP, which may represent the start of a possible time at which the UE may begin transmitting within the COT shared by the initiating UE, within a joint period that includes the last symbol (symbol 13) in the current time slot (e.g., the time slot before the transmission) and the first symbol (symbol 0) in the next time slot (e.g., the time slot in which the UE is to perform the transmission).

[0114] For example, Figure 7 As shown, the COT may be configured with a set of TSPs (TSP1, TSP2, TSP3, and TSP4, as shown). In the illustrated aspect, the set of TSPs may be located in a gap symbol (e.g., symbol 13 of slot n-1). In addition, in some aspects, when the AGC period may correspond to a portion of symbol 0 (e.g., the second half of symbol 0), the set of TSPs may be extended to the AGC symbol (e.g., symbol 0 of slot n). In addition, one of the TSPs (e.g., TSP4) may be aligned with the slot boundary between the gap symbol and the AGC symbol. In some aspects, the UE may obtain a TSP located in a gap symbol (e.g., symbol 13) via cyclic prefix extension. In some aspects, the UE may obtain a transmission start point located in an AGC symbol (e.g., symbol 0) via AGC symbol puncturing.

[0115] In some aspects, the COT sharing information (eg, COT-SI 704) may indicate the set of TSPs. For example, the COT sharing information may indicate the set of TSPs in the resource reservation, and the UE may identify one of the TSPs as the attempted TSP.

[0116] The UE (either the initiating UE or the responding UE) may perform a channel access procedure based at least in part on determining a transmission start point. In some aspects, the UE may perform a channel access procedure based at least in part on a sensing structure associated with the TSP. The sensing structure associated with the TSP may be determined at least in part based on an amount of time between an end of a reference transmission and a transmission start point.

[0117] In some aspects, when the amount of time between the TSP and the end of the reference transmission is less than a first amount of time (e.g., less than 16 μs) and the duration of the transmission is less than a second amount of time (e.g., 584 μs), the TSP may be associated with a Type 2C channel access procedure. Figure 7 As shown, the amount of time t1 between the end of the reference transmission (e.g., the start of symbol 13) and the first TSP (TSP1) may be 9 μs. The UE may determine that 9 μs is less than the first amount of time. When the duration of the UE's transmission is within the second amount of time, the UE may determine that the first TSP is associated with a type 2C channel access procedure based at least in part on 9 μs being less than the first amount of time.

[0118] In some aspects, when the amount of time between the TSP and the end of the reference transmission point is equal to the first amount of time, the TSP may be associated with a type 2B channel access. Figure 7 As shown, the amount of time t2 between the end of the reference transmission and the second TSP (TSP2) may be 16µs. The UE may determine that the second TSP is associated with a type 2B channel access procedure based at least in part on the amount of time between the second TSP and the end of the reference transmission being equal to the first amount of time.

[0119] In some aspects, when the amount of time between the TSP and the end of the reference transmission point is equal to a third amount of time (e.g., 25 μs), the TSP may be associated with a type 2A channel access. Figure 7 As shown, the amount of time t3 between the end of the reference transmission and the third TSP (TSP3) may be 25 µs. The UE may determine that the third TSP is associated with a type 2A channel access procedure based at least in part on the amount of time between the third TSP and the end of the reference transmission being equal to the third amount of time. In addition, the UE may determine that a subsequent TSP (e.g., TSP4) is associated with a type 2A channel access procedure based at least in part on the amount of time between the subsequent TSP and the end of the reference transmission being greater than the third amount of time.

[0120] In some implementations, the initiating UE may not have any advantage in retransmissions over other UEs in responding.The initiating UE may perform a channel access procedure as a responding device to itself based on the available transmission starting point.

[0121] In some implementations, the initiating UE may select a TSP from the set of TSPs based at least in part on the number of priorities indicated in the COT sharing information. For example, the COT sharing information may include a set of one or more bits, and the value of the one or more bits may correspond to the number of priorities associated with the set of TSPs. The initiating UE may determine the priority associated with each transmission start point based at least in part on the number of priorities associated with the set of TSPs. For example, the set of one or more bits may be set to a first value (e.g., 1) to indicate that each TSP in the set of TSPs is associated with the same priority (e.g., the highest priority). As another example, one or more bits may be set to a second value (e.g., 2) to indicate that the first half of the TSPs (e.g., TSP1 and TSP2) are associated with a first priority (e.g., the highest priority) and the second half of the TSPs (e.g., TSP3 and TSP4) are associated with a second priority (e.g., the second highest priority).

[0122] In addition, the COT sharing information indicating the set of TSPs may include a lookup table that maps TSP indexes to TSPs, channel access priority classes (CAPCs), LBT class types, and / or CPEs. For example, the lookup table may include one or more TSP entries corresponding to a CAPC. In some aspects, each of the TSPs may correspond to a different CAPC. In some aspects, multiple TSPs may correspond to the same CAPC. In some aspects, the same TSP may correspond to multiple CAPCs.

[0123] A CAPC may be associated with a SL transmission. The transmission may be a transport block sent via a PSSCH. A CAPC associated with a SL communication may indicate a priority (e.g., latency budget) for the SL communication. In some aspects, a higher CAPC value (e.g., 4) may indicate a lower priority level, while a lower CAPC value (e.g., 1) may indicate a higher priority level.

[0124] The COT sharing information may also indicate a cyclic prefix extension (CPE) length. The UE may send the CPE before sending the SL to facilitate alignment of orthogonal frequency division multiplexing (OFDM) symbols and to preserve the shared COT by preventing other UEs from competing for the shared COT.

[0125] The initiating UE may start sending a communication at the TSP based on the CAPC associated with the communication. The initiating UE may perform LBT in slot symbol 13 (e.g., a gap symbol) just before the TSP corresponding to the CAPC of the communication that the initiating UE intends to send. If the LBT is successful, the initiating UE may transmit during the CPE between the TSP and the slot boundary (e.g., the boundary between the end of symbol 13 and symbol 0 of the next slot). By transmitting during the CPE starting at the TSP, the initiating UE may prevent other UEs from competing for the shared COT. SL communications with high priority (e.g., lower CAPC values) may be assigned an earlier TSP than SL communications with lower priority (e.g., higher CAPC values). In this way, an earlier TSP may be assigned to a UE with a high priority communication to send, thereby preventing other COT-sharing UEs with lower priority communications from obtaining the shared COT. When more than one UE has a high priority communication to send (e.g., multiple UEs with the same CAPC value), the UE may compete for an earlier TSP based on a random selection process. The random TSP selection process may provide a random opportunity for competing UEs to be assigned an earlier TSP. In this regard, each of the competing UEs may select a TSP based on a hash function of multiple TSPs. For example, each of the competing UEs may select a TSP based on a hash function of multiple TSPs and a unique identifier associated with the competing UE.

[0126] In some implementations, prioritization on TSPs may be based on the role of being an initiating UE or a responding UE. For example, one of the TSPs may be reserved for the initiating UE, and other UEs may be prohibited from using the reserved TSP. In an extension of this example, the earliest TSP in the set of TSPs (e.g., TSP1) may be reserved only for the initiating UE, and other UEs may be excluded from accessing it. Other TSPs other than the TSP reserved for the initiating UE may be available for responding UE contention. The COT sharing information may indicate which TSP is reserved.

[0127] On the other hand, the responding UE may treat the reservation differently based on whether the reservation is from the initiating UE or from another UE. In some aspects, the reservation is associated with a source ID (e.g., recorded and readable in SCI-2), and if the source ID of the reservation matches the source ID from the COT shared information, the responding UE knows that the reservation is from the initiating UE of the shared COT. In some aspects, the responding UE may completely prohibit attempting channel access in the time slot where the initiating UE has reserved resources. For example, if a time slot or one of the TSPs before the time slot is reserved for the initiating UE, the responding UE may prohibit attempting channel access not only from the reserved TSP but from all TSPs.

[0128] Alternatively, the responding UE may access the TSP only after detecting that the initiating UE is not using the reserved resources. For example, the responding UE may attempt channel access at a later TSP to detect whether the initiating UE has already accessed the reserved TSP. When the LBT discloses that there is no access of the initiating UE to the reserved TSP, the responding UE may start sending at a later TSP. More stringent conditions may be applied: when the responding UE is not the target recipient of the initiating UE's transmission through the reserved TSP, the responding UE may attempt channel access at a later TSP. In other words, if the responding UE is the target recipient of the initiating UE's transmission through the reserved TSP, the responding UE may refrain from attempting to send at a later TSP even if no activity is detected on the reserved TSP. Whether the responding UE is the target recipient can be read in the reserved destination ID field recorded in SCI-2.

[0129] Alternatively, in order to better utilize the shared spectrum, the responding UE may send SL communications with the initiating UE in FDM. In other words, the responding UE may send in the same time slot as the initiating UE but in a different subchannel. Since FDM should be acquired by aligning the TSP with the initiating UE (i.e., the TSP reserved for the initiating UE is also selected by the responding TSP), so that the type 2 channel access procedure will not be blocked on the UE, the responding UE may attempt to send in FDM when the transmission of the responding UE is not a unicast to the initiating UE but a multicast or broadcast. More stringent conditions may be applied: the responding UE may send SL communications that are not unicast to the initiating UE, and the responding UE is not the target recipient of the transmission of the initiating UE through the reserved TSP. Whether the responding UE is the target recipient can be read in the reserved destination ID field recorded in SCI-2. In other words, the transmission of the initiating UE through the reserved TSP is a unicast to UEs other than the responding UE or a multicast to a group of UEs that do not include the responding UE.

[0130] Although about Figures 5 to 7 The example aspects described provide for mandatory consistency, where the sharable state of resources for a particular COT will not change and the initiating UE will compete with other UEs for access to the sharable resources (without advantage or with advantage (e.g., through priority or reservation)), but the question arises as to whether the network should allow the sharable resources to change to non-sharable.

[0131] In some implementations, the initiating UE may use a later transmission to other UEs to indicate that they can no longer access the shared COT, and the remainder of the COT is reclaimed by the initiating UE.

[0132] Figure 8 is a diagram illustrating a wireless communication system 800 having UEs (e.g., UE 115i, UE 115j, and UE 115k) for NR-U SL operation according to various aspects of the present disclosure. In some examples, the wireless communication system 800 can implement various aspects of the wireless communication network 100. After performing a successful LBT procedure or other clear channel assessment (CCA), the UE 115i can acquire a COT 804 within an unlicensed (e.g., shared) spectrum of the wireless communication system 800 and transmit COT sharing information to other UEs to share the acquired COT.

[0133] According to the illustrated aspect, UE 115i may send COT sharing information via COT-SI. When generating COT-SI 805a, UE 115i may determine the time and frequency resources (t×f) that define COT 804, and may also determine the time and frequency resource set that defines the reserved resource set (such as reserved resource region 807). UE 115i may then send COT-SI 805a to neighboring UEs (such as UE 115j and UE 115k) via SL message 803. COT-SI 805a may include the remaining duration of COT 804, the time and frequency resources (t×f) that define COT 804, and the time and frequency resource set that defines the reserved resource region 807.

[0134] By including a time-frequency resource set defining a reserved resource region 807, UE 115i provides additional information defining a shareable COT region within COT 804 to UE 115j and UE 115k. A shareable COT region may also include a shareable TDM region and / or a shareable FDM region. Other UEs (such as UE 115j and UE 115k) may perform TDM sharing in a shareable TDM region and perform FDM sharing in a shareable FDM region. UE 115j and UE 115k will also know that the reserved resource region 807 is not shareable, and thus, UE 115j and UE 115k will not attempt to access the shared spectrum within COT 804 that falls within the reserved resource region 807.

[0135] Additionally or alternatively, UE 115i may generate a second COT-SI 805b indicating that the remaining duration of COT 804 becomes shareable. For example, COT-SI 805a may determine the time and frequency resources (t×f) defining COT 804, but may not further indicate when COT 804 will become shareable. On the other hand, COT-SI 805b may provide additional information defining a shareable COT region within COT 804 to UE 115j and UE 115k. For example, COT-SI 805b may be located at the end of reserved resource region 807 and used as a marker indicating the starting point of the shared COT. UE 115j and UE 115k that receive and decode COT-SI 805b in proximity to UE 115i may know that the remaining portion of COT 804 is now shareable, and may acquire a time slot in the shared COT to transmit SL communications.

[0136] Figure 8 The example aspects illustrated in may be more general aspects of a design that allows an initiating UE to change its mind about a shared COT. Figure 8The illustrated aspects show how UE 115i changes a previously sharable region of COT 804 to a non-sharable region. According to the illustrated aspects, UE 115i may send a COT reclaim signal 809 to other UEs, such as UE 115j and UE 115k. COT reclaim signal 809 restores the remaining portion of COT 804 from the shared COT to the reserved COT. After receiving COT reclaim signal 809, UE 115j and UE 115k will prohibit access to the remaining portion of COT 804. After restoring the remaining portion of COT 804 to the reserved COT, UE 115i may send SL communications in the remaining portion of COT 804 without the risk of conflict with other competing UEs.

[0137] In some aspects, the COT retract signal 809 may be a flag signal indicating the end of the current time slot containing the COT retract signal as the end of the shared COT. Alternatively, the COT retract signal 809 may indicate that the end of the sharing of the COT is offset by one or more time slots from the current time slot containing the COT retract signal. The COT retract signal 809 may define the amount of time slots as the offset.

[0138] In some aspects, the COT reclaim signal 809 may be sent via COT-SI, SCI-1, or SCI-2 information contained in the PSFCH (requiring a different format than PFO). In some aspects, in order to act as a flag signal indicating the end of the current slot as the end of the shared COT, the COT reclaim signal 809 may be sent as a PSFCH mapped to one of the transmissions of the initiating UE when HARQ feedback is disabled to implicitly indicate that the previously shared COT is reclaimed.

[0139] Fig.9A 900 is a signaling diagram of a wireless communication method 900 according to some aspects of the present disclosure. The actions of the communication method 900 may be performed by a computing device (e.g., a processor, a processing circuit, and / or other suitable components) of a communication device or other suitable means for performing these actions. For example, wireless communication devices such as UE 115i and UE 115j may utilize one or more components (such as a processor 1002, a memory 1004, a COT sharing module 1008, a transceiver 1010, a modem 1012, and one or more antennas 1016) to perform various aspects of the method 900.

[0140] At action 902, the UE 115i may perform a successful LBT. The UE 115i may perform a Category 1 LBT, a Category 2 LBT, a Category 3 LBT, and / or a Category 4 LBT to gain access to a COT in an unlicensed spectrum.

[0141] At action 904, UE 115i may send COT sharing information to UE 115j via COT-SI, sidelink control information (e.g., SCI-1, SCI-2), RRC message, PSCCH message, PSSCH message, or other suitable communication. For example, UE 115i may send COT sharing information in the SL_COT_SharingInformation field via sidelink control information 2 (SCI-2). In some aspects, the COT sharing information may include information (e.g., parameters, resources, settings, commands, etc.) that enables UE 115i to share the COT with UE 115j. Sharing the COT with one or more other UEs may enable the other UEs to send and / or receive communications during the COT in an efficient and coordinated manner. In some aspects, the COT sharing information may include an identifier associated with a set of UEs that share the COT. The UE identifier may include a layer one identifier that is unique to each UE that shares the COT.

[0142] At action 906, UE 115j may decode the COT sharing information received from UE 115i. The COT sharing information may include a COT resource allocation indicating resources available to UE 115j to share the COT. The COT sharing information may also provide priority information and / or reservation information for a set of transmission starting points (TSPs).

[0143] At act 908, UE 115j may send SL communications to UE 115i in the resources allocated in the COT sharing information. UE 115j may send the SL communications based on a TSP associated with a priority (eg, CAPC) associated with UE 115j.

[0144] At action 910, UE 115i may acquire a TSP for sending SL communications in a shared COT. UE 115i may acquire the TSP by competing without any advantage to UE 115j. Alternatively, UE 115i may acquire the TSP based on a priority (e.g., CAPC) associated with UE 115i. For example, UE 115i may have a lower CAPC value indicating a higher priority than UE 115j. Therefore, UE 115i may transmit before UE 115j. Alternatively, UE 115i may acquire the TSP based on a TSP reserved specifically for UE 115i.

[0145] At action 912, UE 115i may send SL communications to UE 115j in resources starting with the acquired (or reserved) TSP. For example, UE 115i may transmit during a cyclic prefix extension (CPE) between the TSP and a slot boundary (e.g., the boundary between the end of symbol 13 and symbol 0 of the next slot). By transmitting during the CPE starting at the TSP, UE 115i may prevent other UEs from competing for the shared COT.

[0146] Fig. 9B 901 is a signaling diagram of a wireless communication method 901 according to some aspects of the present disclosure. The actions of the communication method 901 may be performed by a computing device (e.g., a processor, a processing circuit, and / or other suitable components) of a communication device or other suitable means for performing these actions. For example, wireless communication devices such as UE 115i and UE 115j may utilize one or more components (such as a processor 1002, a memory 1004, a COT sharing module 1008, a transceiver 1010, a modem 1012, and one or more antennas 1016) to perform various aspects of the method 901.

[0147] At action 902, the UE 115i may perform a successful LBT. The UE 115i may perform a Category 1 LBT, a Category 2 LBT, a Category 3 LBT, and / or a Category 4 LBT to gain access to a COT in an unlicensed spectrum.

[0148] At action 904, UE 115i may send COT sharing information to UE 115j via COT-SI, sidelink control information (e.g., SCI-1, SCI-2), RRC message, PSCCH message, PSSCH message, or other suitable communication. For example, UE 115i may send COT sharing information in the SL_COT_SharingInformation field via sidelink control information 2 (SCI-2). In some aspects, the COT sharing information may include information (e.g., parameters, resources, settings, commands, etc.) that enables UE 115i to share the COT with UE 115j. Sharing the COT with one or more other UEs may enable the other UEs to send and / or receive communications during the COT in an efficient and coordinated manner. In some aspects, the COT sharing information may include an identifier associated with a set of UEs that share the COT. The UE identifier may include a layer one identifier that is unique to each UE that shares the COT.

[0149] At action 906, UE 115j may decode the COT sharing information received from UE 115i. The COT sharing information may include a COT resource allocation indicating resources available to UE 115j to share the COT. The COT sharing information may also provide priority information and / or reservation information for a set of transmission starting points (TSPs).

[0150] At act 908, UE 115j may send SL communications to UE 115i in the resources allocated in the COT sharing information. UE 115j may send the SL communications based on a TSP associated with a priority (eg, CAPC) associated with UE 115j.

[0151] At action 914, UE 115i may send a COT reclaim signal to reclaim the remaining portion of the shared COT and convert the shared COT to a reserved COT. The COT reclaim signal prohibits UE 115j from accessing the remaining portion of the shared COT.

[0152] At act 916, UE 115i may send SL communications to UE 115j in resources in the reclaimed COT. Since the reclaimed COT is reserved for UE 115i, UE 115i does not need to contend with other UEs to transmit SL communications.

[0153] Fig.10 1 is a block diagram of an exemplary UE 1000 according to some aspects of the present disclosure. As shown, the UE 1000 may include a processor 1002, a memory 1004, a COT sharing module 1008, a transceiver 1010 including a modem subsystem 1012 and a radio frequency (RF) unit 1014, and one or more antennas 1016. These elements may be coupled to each other via one or more buses and communicate with each other directly or indirectly. The UE 1000 may be similar to the above reference 1. Figure 3 The UE 115i or UE 115j in question. The COT sharing module 1008 may include the above reference Figure 3 The LBT logic 306, COT structure scheduler 307 and COT shared information 308 are discussed.

[0154] The processor 1002 may include a central processing unit (CPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a controller, a field programmable gate array (FPGA) device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein. The processor 1002 may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in combination with a DSP core, or any other such configuration.

[0155] Memory 1004 may include cache memory (e.g., cache memory of processor 1002), random access memory (RAM), magnetoresistive RAM (MRAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, solid-state memory devices, hard drives, other forms of volatile and non-volatile memory, or a combination of different types of memory. In some examples, memory 1004 includes non-transitory computer-readable media. Memory 1004 may store instructions 1006. Instructions 1006 may include instructions that, when executed by processor 1002, cause processor 1002 to perform various aspects of the present disclosure described herein (e.g., Figures 3 to 9B Instructions 1006 may also be referred to as code. The terms "instructions" and "code" should be broadly interpreted to include any type of computer-readable statements. For example, the terms "instructions" and "code" may refer to one or more programs, routines, subroutines, functions, procedures, etc. "Instructions" and "code" may include a single computer-readable statement or multiple computer-readable statements.

[0156] The COT sharing module 1008 may be implemented via hardware, software, or a combination thereof. For example, the COT sharing module 1008 may be implemented as a processor, circuit, and / or instructions 1006 stored in the memory 1004 and executed by the processor 1002. Additionally or alternatively, the COT sharing module 1008 may be implemented in any combination of hardware and software, and in some implementations may involve, for example, the processor 1002, the memory 1004, the instructions 1006, the transceiver 1010, and / or the modem 1012. In some aspects, the COT sharing module 1008 may be implemented as a processor, circuit, and / or instructions 1006 stored in the memory 1004 and executed by the processor 1002. Figures 3 to 9B For example, the COT sharing module 1008 may perform a listen before talk (LBT) procedure. The COT sharing module 1008 may obtain a channel occupation time (COT) based on the success of the LBT procedure. The COT sharing module 1008 may send COT sharing information for sharing the COT with the second UE during the COT.

[0157] As shown, the transceiver 1010 may include a modem subsystem 1012 and an RF unit 1014. The transceiver 1010 may be configured to communicate bidirectionally with other devices, such as the BS 105 and / or the UE 115. The modem subsystem 1012 may be configured to modulate and / or encode data from the memory 1004 according to a modulation and coding scheme (MCS) (e.g., a low-density parity check (LDPC) coding scheme, a turbo decoding scheme, a convolutional decoding scheme, a digital beamforming scheme, etc.). The RF unit 1014 may be configured to process (e.g., perform analog-to-digital conversion or digital-to-analog conversion, etc.) the modulated / encoded data from the modem subsystem 1012 (for outbound transmissions) or transmissions originating from another source, such as the UE 115 or the BS 105. The RF unit 1014 may be further configured to perform analog beamforming in conjunction with digital beamforming. Although shown as being integrated together in the transceiver 1010, the modem subsystem 1012 and the RF unit 1014 may be separate devices that are coupled together to enable the UE 1000 to communicate with other devices.

[0158] The RF unit 1014 may provide modulated and / or processed data, such as a data packet (or more generally, a data message that may include one or more data packets and other information), to the antenna 1016 for transmission to one or more other devices. The antenna 1016 may also receive data messages sent from other devices. The antenna 1016 may provide the received data message for processing and / or demodulation at the transceiver 1010. The antenna 1016 may include multiple antennas of similar or different designs to maintain multiple transmission links. The RF unit 1014 may configure the antenna 1016.

[0159] In some examples, the UE 1000 may include multiple transceivers 1010 that implement different RATs (e.g., NR and LTE). In some examples, the UE 1000 may include a single transceiver 1010 that implements multiple RATs (e.g., NR and LTE). In some examples, the transceiver 1010 may include various components, where different combinations of the components may implement the RATs.

[0160] Fig.111 is a block diagram of an exemplary network unit 1100 according to some aspects of the present disclosure. The network unit 1100 may be a BS 105, a CU 210, a DU 230, or a RU 240 as discussed above. As shown, the network unit 1100 may include a processor 1102, a memory 1104, a COT sharing module 1108, a transceiver 1110 including a modem subsystem 1112 and an RF unit 1114, and one or more antennas 1116. These elements may be coupled to each other, for example, via one or more buses and communicate with each other directly or indirectly.

[0161] The processor 1102 may have various features as a particular type of processor. For example, these features may include a CPU, a DSP, an ASIC, a controller, an FPGA device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein. The processor 1102 may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in combination with a DSP core, or any other such configuration.

[0162] Memory 1104 may include cache memory (e.g., cache memory of processor 1102), RAM, MRAM, ROM, PROM, EPROM, EEPROM, flash memory, solid-state memory devices, one or more hard disk drives, memristor-based arrays, other forms of volatile and nonvolatile memory, or a combination of different types of memory. In some examples, memory 1104 may include non-transitory computer-readable media. Memory 1104 may store instructions 1106. Instructions 1106 may include instructions that, when executed by processor 1102, cause processor 1102 to perform the operations described herein (e.g., Figures 3 to 9B Instructions 1106 may also be referred to as code, which may be broadly interpreted to include any type of computer-readable statements.

[0163] The COT sharing module 1108 may be implemented via hardware, software, or a combination thereof. For example, the COT sharing module 1108 may be implemented as a processor, circuit, and / or instructions 1106 stored in the memory 1104 and executed by the processor 1102. Additionally or alternatively, the COT sharing module 1108 may be implemented in any combination of hardware and software, and in some specific implementations may involve, for example, the processor 1102, the memory 1104, the instructions 1106, the transceiver 1110, and / or the modem 1112. In some aspects, the COT sharing module 1108 may be implemented as a processor, circuit, and / or instructions 1106 stored in the memory 1104 and executed by the processor 1102. Figures 3 to 9BFor example, the COT sharing module 1108 may perform a listen before talk (LBT) procedure. The COT sharing module 1108 may obtain a channel occupation time (COT) based on the success of the LBT procedure. The COT sharing module may send COT sharing information for sharing the COT with the second UE to the second UE during the COT.

[0164] As shown, the transceiver 1110 may include a modem subsystem 1112 and an RF unit 1114. The transceiver 1110 may be configured to communicate bidirectionally with other devices, such as the UE 115. The modem subsystem 1112 may be configured to modulate and / or encode data according to an MCS (e.g., an LDPC decoding scheme, a turbo decoding scheme, a convolutional decoding scheme, a digital beamforming scheme, etc.). The RF unit 1114 may be configured to process (e.g., perform analog-to-digital conversion or digital-to-analog conversion, etc.) the modulated / encoded data from the modem subsystem 1112 (for outbound transmissions) or transmissions originating from another source, such as the UE 115. The RF unit 1114 may be further configured to perform analog beamforming in conjunction with digital beamforming. Although shown as being integrated together in the transceiver 1110, the modem subsystem 1112 and / or the RF unit 1114 may be separate devices that are coupled together at the network unit 1100 to enable the network unit 1100 to communicate with other devices.

[0165] The RF unit 1114 may provide modulated and / or processed data, such as a data packet (or more generally, a data message that may contain one or more data packets and other information), to the antenna 1116 for transmission to one or more other devices. For example, according to aspects of the present disclosure, this may include a configuration indicating multiple sub-slots within a time slot. The antenna 1116 may also receive data messages sent from other devices and provide the received data messages for processing and / or demodulation at the transceiver 1110. The antenna 1016 may include multiple antennas of similar design or different design to maintain multiple transmission links.

[0166] In some examples, the network unit 1100 may include multiple transceivers 1110 that implement different RATs (e.g., NR and LTE). In some examples, the network unit 1100 may include a single transceiver 1110 that implements multiple RATs (e.g., NR and LTE). In some examples, the transceiver 1110 may include various components, where different combinations of the components may implement the RATs.

[0167] Fig.121000 is a flow chart of a communication method 1200 according to some aspects of the present disclosure. Various aspects of the method 1200 may be performed by a computing device (e.g., a processor, a processing circuit, and / or other suitable components) of a wireless communication device or other suitable means for performing these aspects. For example, a wireless communication device (such as UE 115) may utilize one or more components (such as processor 1002, memory 1004, COT sharing module 1008, transceiver 1010, modem 1012, and one or more antennas 1016) to perform various aspects of the method 1200. The method 1200 may employ mechanisms similar to those in networks 100 and 200 and with respect to Figures 3 to 9B As illustrated, method 1200 includes multiple enumerated aspects, but method 1200 may include additional aspects before, after, and between the enumerated aspects. In some aspects, one or more of these enumerated aspects may be omitted or performed in a different order.

[0168] At action 1210, method 1200 includes a first UE (e.g., UE 115i, UE 1000) performing a listen-before-talk (LBT) procedure. The first UE may perform an LBT procedure or other clear channel assessment (CCA) on one or more SL communication channels. In some instances, the first UE may perform an LBT procedure or other CCA to obtain access to a channel occupancy time (COT) in an unlicensed (e.g., shared) spectrum. For example, the first UE may perform Category 1 LBT, Category 2 LBT, Category 3 LBT, and / or Category 4 LBT to obtain access to the COT in an unlicensed spectrum. In some aspects, the first UE may perform LBT in one or more time resources, space resources, and / or frequency resources. These frequency resources may include spectrum, frequency band, frequency subband, frequency subchannel, resource element, resource block, and / or frequency interlace. These time resources may include time slots, subslots, symbols, subframes, or any other suitable time resources. In some aspects, the first UE may perform LBT for one or more directional beams (e.g., beams in the direction of UEs to which the first UE intends to send communications and / or receive communications from).

[0169] At act 1220, method 1200 includes the first UE obtaining a channel occupancy time (COT) based on the LBT procedure success at act 1210. The first UE may obtain the COT to send a communication to another UE or to send other communications. Additionally or alternatively, the first UE may share the COT with other UEs.

[0170] At action 1230, method 1200 includes the first UE sending COT sharing information to the second UE (e.g., UE 115j, UE 1000) to share the COT with the second UE. The first UE may send the COT sharing information to the second UE during the COT. The COT sharing information may include a COT resource allocation, which indicates the resources that the second UE can use to share the COT. In some aspects, the first UE may send the COT sharing information to the second UE and other UEs (e.g., a group of UEs, a set of UEs). The first UE may send the COT sharing information including the resource allocation to the set of UEs to share the COT with the set of UEs.

[0171] In some aspects, the first UE may send COT sharing information via COT structure information (COT-SI), sidelink control information (e.g., SCI-1, SCI-2), RRC message, PSCCH message, PSSCH message, or other suitable communication. For example, the first UE may send COT sharing information in the SL_COT_SharingInformation field via sidelink control information 2 (SCI-2).

[0172] In some aspects, the COT sharing information may include information (e.g., parameters, resources, settings, commands, etc.) that enables the first UE to share the COT with other UEs (e.g., the second UE). Sharing the COT with other UEs may enable the other UEs to send and / or receive communications during the COT in an efficient and coordinated manner. In some aspects, the COT sharing information may include an identifier associated with the set of UEs sharing the COT. The UE identifier may include a layer one identifier that is unique to each UE sharing the COT.

[0173] In some aspects, the COT sharing information may include a time resource allocation associated with the COT sharing. For example, the time resource allocation may include a COT start time, a COT end time, and / or a COT duration. The time resource allocation may include time resources (e.g., time slots, sub-time slots, symbols, frames, etc.) allocated to the set of UEs sharing the COT. For example, the time resource allocation may indicate an index indicating a starting time slot and / or sub-time slot allocated to the set of UEs. The time resource allocation may indicate the number of time resources allocated to the set of UEs (e.g., the number of time slots, sub-time slots, and / or symbols). The first UE may indicate the time resource allocation to the UEs sharing the COT in a time domain resource allocation (TDRA) via SCI-1.

[0174] In some aspects, the COT sharing information may include frequency resource allocations (e.g., frequency ranges) associated with the COT sharing. For example, the frequency resource allocations may include a starting frequency (e.g., a starting frequency subchannel index, a starting frequency band, a starting frequency interlace). The frequency resource allocations may include an ending frequency (e.g., an ending subchannel, an ending frequency band). The frequency resource allocations may include a frequency interlace (e.g., a frequency interlace index, an index of a subchannel). The frequency resource allocations may indicate frequency resources allocated to a set of UEs that share the COT with the first k UEs. The first UE may indicate the frequency resource allocations to the UEs that share the COT in a frequency domain resource allocation (FDRA) via SCI-1.

[0175] In some aspects, the first UE may send a flag indicating that the first UE is sharing the COT. In this regard, the first UE may send a flag indicating that the first UE is sharing the COT to one or more other UEs via an SCI (e.g., SCI-1, SCI-2). The flag may include a single-bit (e.g., 0 or 1) indicator, a multi-bit indicator, a code point, or other indicators indicating that other UEs (e.g., UEs receiving the flag) can share the COT.

[0176] In some aspects, the first UE may send the flag to the UE in the SCI-2 via the PSSCH. The SCI-2 may include a destination identifier associated with the second UE and / or other UEs, indicating that the first UE shares the COT with the second UE and / or other UEs. In some instances, if the SCI-2 includes an identifier that matches an identifier associated with the receiving UE, a UE that receives and decodes the SCI-2 near the first UE may share the COT with the first UE.

[0177] In some aspects, the COT sharing information may indicate a groupcast identifier associated with a set of UEs for sharing the COT with the first UE. In this regard, the first UE may send the COT sharing information via SCI-2. The SCI-2 may include a groupcast identifier indicating a set of UEs including the second UE that may share the COT.

[0178] In some aspects, the COT sharing information may indicate a set of transmission start points (TSPs). In some implementations, each of the TSPs may have the same priority. In some implementations, the TSPs may have a priority associated with a channel access priority class (CAPC). The COT sharing information indicating the TSPs may include a lookup table that maps a TSP index to a TSP, a channel access priority class (CAPC), an LBT class type, and / or a CPE. For example, the lookup table may include one or more TSP entries corresponding to a CAPC. In some aspects, each of the TSPs may correspond to a different CAPC. In some aspects, multiple TSPs may correspond to the same CAPC. In some aspects, the same TSP may correspond to multiple CAPCs. The CAPC may be associated with SL communication. The SL communication may be a transport block sent via a PSSCH. The CAPC associated with the SL communication may indicate the priority (e.g., delay budget) of the SL communication. In some aspects, a higher CAPC value (e.g., 4) may indicate a lower priority level, while a lower CAPC value (e.g., 1) may indicate a higher priority level. In some implementations, an early TSP (eg, a first TSP) can be reserved exclusively for the UE that initiates the COT (eg, the first UE).

[0179] At act 1240, method 1200 includes the first UE acquiring one of the TSPs within the shared COT. The first UE may acquire the TSP without an advantage in a contention process or with an allocated advantage (eg, through priority or reservation).

[0180] At action 1250, method 1200 includes the first UE sending a SL communication in resources starting with the acquired (or reserved) TSP. For example, the first UE may transmit during a cyclic prefix extension (CPE) between the TSP and a slot boundary (e.g., the boundary between the end of symbol 13 and symbol 0 of the next slot). By transmitting during the CPE starting at the TSP, the first UE may prevent other UEs from competing for the shared COT. The transmission length may be within a slot after the TSP, or within a plurality of slots consecutively after the TSP until the SL communication ends.

[0181] Fig.13 is a flow chart of a communication method 1300 according to some aspects of the present disclosure. Some actions of method 1300 are similar to those of method 1200, some details are omitted for brevity, and the corresponding actions of method 1200 may be reviewed for additional details.

[0182] Various aspects of the method 1300 may be performed by a computing device (e.g., a processor, a processing circuit, and / or other suitable components) of a wireless communication device or other suitable means for performing these aspects. For example, a wireless communication device (such as UE 115) may utilize one or more components (such as processor 1002, memory 1004, COT sharing module 1008, transceiver 1010, modem 1012, and one or more antennas 1016) to perform various aspects of the method 1300. The method 1300 may employ mechanisms similar to those in networks 100 and 200 and with respect to Figures 3 to 9B As illustrated, method 1300 includes multiple enumerated aspects, but method 1300 may include additional aspects before, after, and between the enumerated aspects. In some aspects, one or more of these enumerated aspects may be omitted or performed in a different order.

[0183] At action 1310, method 1300 includes a first UE (e.g., UE 115i, UE 1000) performing a listen-before-talk (LBT) procedure. The first UE may perform an LBT procedure or other clear channel assessment (CCA) on one or more SL communication channels. In some instances, the first UE may perform an LBT procedure or other CCA to obtain access to a channel occupancy time (COT) in an unlicensed (e.g., shared) spectrum. For example, the first UE may perform Category 1 LBT, Category 2 LBT, Category 3 LBT, and / or Category 4 LBT to obtain access to the COT in an unlicensed spectrum. In some aspects, the first UE may perform LBT in one or more time resources, space resources, and / or frequency resources. These frequency resources may include spectrum, frequency band, frequency subband, frequency subchannel, resource element, resource block, and / or frequency interlace. These time resources may include time slots, subslots, symbols, subframes, or any other suitable time resources. In some aspects, the first UE may perform LBT for one or more directional beams (e.g., beams in the direction of UEs to which the first UE intends to send communications and / or receive communications from).

[0184] At act 1320, method 1300 includes the first UE obtaining a channel occupancy time (COT) based on the LBT procedure success at act 1310. The first UE may obtain the COT to send a communication to another UE or to send other communications. Additionally or alternatively, the first UE may share the COT with other UEs.

[0185] At action 1330, method 1300 includes the first UE sending COT sharing information to the second UE (e.g., UE 115j, UE 1000) to share the COT with the second UE. The first UE may send the COT sharing information to the second UE during the COT. The COT sharing information may include a COT resource allocation, which indicates the resources that the second UE can use to share the COT. In some aspects, the first UE may send the COT sharing information to the second UE and other UEs (e.g., a group of UEs, a set of UEs). The first UE may send the COT sharing information including the resource allocation to the set of UEs to share the COT with the set of UEs.

[0186] In some aspects, the first UE may send COT sharing information via COT structure information (COT-SI), sidelink control information (e.g., SCI-1, SCI-2), RRC message, PSCCH message, PSSCH message, or other suitable communication. For example, the first UE may send COT sharing information in the SL_COT_SharingInformation field via sidelink control information 2 (SCI-2).

[0187] In some aspects, the COT sharing information may include information (e.g., parameters, resources, settings, commands, etc.) that enables the first UE to share the COT with other UEs (e.g., the second UE). Sharing the COT with other UEs may enable the other UEs to send and / or receive communications during the COT in an efficient and coordinated manner. In some aspects, the COT sharing information may include an identifier associated with the set of UEs sharing the COT. The UE identifier may include a layer one identifier that is unique to each UE sharing the COT.

[0188] In some aspects, the COT sharing information may include a time resource allocation associated with the COT sharing. For example, the time resource allocation may include a COT start time, a COT end time, and / or a COT duration. The time resource allocation may include time resources (e.g., time slots, sub-time slots, symbols, frames, etc.) allocated to the set of UEs sharing the COT. For example, the time resource allocation may indicate an index indicating a starting time slot and / or sub-time slot allocated to the set of UEs. The time resource allocation may indicate the number of time resources allocated to the set of UEs (e.g., the number of time slots, sub-time slots, and / or symbols). The first UE may indicate the time resource allocation to the UEs sharing the COT in a time domain resource allocation (TDRA) via SCI-1.

[0189] In some aspects, the COT sharing information may include frequency resource allocations (e.g., frequency ranges) associated with the COT sharing. For example, the frequency resource allocations may include a starting frequency (e.g., a starting frequency subchannel index, a starting frequency band, a starting frequency interlace). The frequency resource allocations may include an ending frequency (e.g., an ending subchannel, an ending frequency band). The frequency resource allocations may include a frequency interlace (e.g., a frequency interlace index, an index of a subchannel). The frequency resource allocations may indicate frequency resources allocated to a set of UEs that share the COT with the first UE. The first UE may indicate the frequency resource allocations to the UEs that share the COT in a frequency domain resource allocation (FDRA) via SCI-1.

[0190] In some aspects, the first UE may send a flag indicating that the first UE is sharing the COT. In this regard, the first UE may send a flag indicating that the first UE is sharing the COT to one or more other UEs via an SCI (e.g., SCI-1, SCI-2). The flag may include a single-bit (e.g., 0 or 1) indicator, a multi-bit indicator, a code point, or other indicators indicating that other UEs (e.g., UEs receiving the flag) can share the COT.

[0191] In some aspects, the first UE may send the flag to the UE in the SCI-2 via the PSSCH. The SCI-2 may include a destination identifier associated with the second UE and other UEs, indicating that the first UE shares the COT with the second UE and / or other UEs. In some instances, if the SCI-2 includes an identifier that matches an identifier associated with the receiving UE, a UE that receives and decodes the SCI-2 near the first UE may share the COT with the first UE.

[0192] In some aspects, the COT sharing information may indicate a groupcast identifier associated with a set of UEs for sharing the COT with the first UE. In this regard, the first UE may send the COT sharing information via SCI-2. The SCI-2 may include a groupcast identifier indicating a set of UEs including the second UE that may share the COT.

[0193] At action 1340, method 1300 includes the first UE sending a COT reclaim signal. The COT reclaim signal restores the remaining portion of the shared COT to a reserved state. After receiving the COT reclaim signal, other UEs are prohibited from accessing the remaining portion of the COT. After restoring the remaining portion of the shared COT to the reserved COT, the first UE can send communications in the remaining portion of the COT without risk of conflict with other competing UEs.

[0194] In some aspects, the COT retract signal is a flag signal that indicates the end of the current time slot containing the COT retract signal as the end of the shared COT. Alternatively, the COT retract signal may indicate that the end of the sharing of the COT is offset by one or more time slots from the current time slot containing the COT retract signal. The COT retract signal may define the amount of time slots as the offset.

[0195] In some aspects, the COT reclaim signal may be sent via information contained in COT-SI, SCI-1, SCI-2, or PSFCH (e.g., using a format other than PFO). In some aspects, in order to act as a flag signal indicating the end of the current slot as the end of the shared COT, the COT reclaim signal may be sent as a PSFCH mapped to one of the transmissions of the initiating UE when HARQ feedback is disabled to implicitly indicate that the previously shared COT is reclaimed.

[0196] At action 1350, method 1300 includes the first UE sending a SL communication in resources starting with the acquired (or reserved) TSP. For example, the first UE may transmit during a cyclic prefix extension (CPE) between the TSP and a slot boundary (e.g., the boundary between the end of symbol 13 and symbol 0 of the next slot). By transmitting during the CPE starting at the TSP, the first UE may prevent other UEs from competing for the shared COT. The transmission length may be within a slot after the TSP, or within a plurality of slots consecutively after the TSP until the SL communication ends.

[0197] Fig.14 1400 is a flow chart of a communication method 1400 according to some aspects of the present disclosure. Various aspects of the method 1400 may be performed by a computing device (e.g., a processor, processing circuitry, and / or other suitable components) of a wireless communication device or other suitable means for performing these aspects. For example, a wireless communication device (such as UE 115) may utilize one or more components (such as processor 1002, memory 1004, COT sharing module 1008, transceiver 1010, modem 1012, and one or more antennas 1016) to perform various aspects of the method 1400. The method 1200 may employ mechanisms similar to those in networks 100 and 200 and with respect to Figures 3 to 9B As illustrated, method 1400 includes multiple enumerated aspects, but method 1400 may include additional aspects before, after, and between the enumerated aspects. In some aspects, one or more of these enumerated aspects may be omitted or performed in a different order.

[0198] At act 1410, method 1400 includes a first UE (e.g., UE 115j) receiving, from a second UE (e.g., UE 115i), a SL message indicating a shared channel occupation time (COT) and one or more TSPs located in the COT. Aspects of act 1410 may be similar to act 1230 of method 1200 or act 130 of method 1300, but from the perspective of a responding UE.

[0199] At action 1420, method 1400 includes the first UE attempting to send a SL communication at one of the TSPs, wherein the attempted sending is based on checking the reservation status of one of the TSPs. The reservation status may be indicated in the COT sharing information received from the second UE. If one of the TSPs is already reserved by the second UE, the first UE may completely prohibit access to any of the TSPs. Alternatively, the first UE may access a subsequent TSP only after detecting that the second UE is not using the reserved TSP. Alternatively, in order to better utilize the shared spectrum, the first UE may send the SL communication with the second UE in FDM.

[0200] Other aspects of the present disclosure include the following:

[0201] Aspect 1 includes a method of wireless communication performed by a first user equipment (UE), the method comprising: performing a listen-before-talk (LBT) procedure; obtaining a channel occupancy time (COT) based on the success of the LBT procedure; sending a sidelink message to a second UE during the COT to notify the second UE of a shared portion of the COT; obtaining a first transmission start point among one or more transmission start points within a remaining portion of the COT; and sending sidelink communication within the COT after obtaining the first transmission start point.

[0202] Aspect 2 includes the method according to aspect 1, wherein the acquiring the first transmission starting point includes competing with at least the second UE for the first transmission starting point among the one or more transmission starting points.

[0203] Aspect 3 includes the method according to any one of aspects 1 to 2, wherein the competing for the first one of the one or more transmission starting points includes performing a channel access procedure.

[0204] Aspect 4 includes a method according to any one of aspects 1 to 3, wherein the type of the channel access procedure is based on a gap between the first of the one or more transmission start points and an end of a previous transmission in the COT.

[0205] Aspect 5 includes the method according to any one of aspects 1 to 4, wherein the previous sending is the sending of the COT shared information.

[0206] Aspect 6 includes a method according to any one of aspects 1 to 5, wherein the previous transmission is a most recent transmission from the first UE.

[0207] Aspect 7 includes a method according to any one of aspects 1 to 6, wherein the previous transmission is a most recent transmission from the second UE.

[0208] Aspect 8 includes a method according to any one of aspects 1 to 7, wherein the first UE has a higher priority than the second UE in acquiring the first transmission start point among the one or more transmission start points.

[0209] Aspect 9 includes the method according to any one of aspects 1 to 8, wherein the first UE has a higher priority than the second UE based on a channel access priority class (CAPC).

[0210] Aspect 10 includes the method according to any one of aspects 1 to 9, wherein the first transmission starting point is reserved only for the first UE.

[0211] Aspect 11 includes the method according to any one of aspects 1 to 10, wherein the first transmission start point is an initial transmission start point among the one or more transmission start points.

[0212] Aspect 12 includes a method according to any one of aspects 1 to 11, wherein the first transmission start point of the one or more transmission start points is located in a gap symbol of a time slot.

[0213] Aspect 13 includes the method according to any one of aspects 1 to 12, wherein said obtaining the first transmission starting point is achieved via cyclic prefix extension.

[0214] Aspect 14 includes the method according to any one of aspects 1 to 13, wherein the first of the one or more transmission starting points is located in an automatic gain control (AGC) symbol of a time slot.

[0215] Aspect 15 includes the method according to any one of aspects 1 to 14, wherein said obtaining the first transmission starting point is achieved via AGC symbol puncturing.

[0216] Aspect 16 includes the method according to any one of aspects 1 to 15, wherein the sending of the COT sharing information includes sending an indication of the one or more transmission starting points.

[0217] Aspect 17 includes a method according to any one of aspects 1 to 16, wherein the sending of the indication of the one or more transmission starting points includes sending sidelink control information (SCI) including the indication of the one or more transmission starting points.

[0218] Aspect 18 includes a method according to any one of aspects 1 to 17, wherein the indication of the one or more transmission starting points is provided in sidelink control information (SCI) of the COT.

[0219] Aspect 19 includes a method of wireless communication performed by a first user equipment (UE), the method comprising: performing a listen-before-talk (LBT) procedure; obtaining a channel occupation time (COT) based on the success of the LBT procedure; sending COT sharing information for sharing the COT with the second UE during the COT; sending a COT retraction signal indicating the end of the sharing of the COT to the second UE during the COT; and after the end of the sharing of the COT, sending side link communication in a remaining part of the COT.

[0220] Aspect 20 includes the method of aspect 19, wherein the COT reclaim signal indicates that the end of the sharing of the COT is at the end of a current time slot containing the COT reclaim signal.

[0221] Aspect 21 includes the method according to any one of aspects 19 to 20, wherein the COT retract signal indicates that the end of the sharing of the COT is offset by one or more time slots from a current time slot containing the COT retract signal.

[0222] Aspect 22 includes a method according to any one of aspects 19 to 21, wherein sending the COT retrieval signal includes sending the COT retrieval signal in sidelink control information (SCI).

[0223] Aspect 23 includes the method according to any one of aspects 19 to 22, wherein the sending the COT back-off signal includes sending the COT back-off signal in a physical sidelink feedback channel (PSFCH).

[0224] Aspect 24 includes a method of wireless communication performed by a first user equipment (UE), the method comprising receiving a sidelink message indicating a shared portion of a channel occupancy time (COT) from a second UE; selecting a first transmission start point from one or more transmission start points within the COT based on a reservation status of the first transmission start point; and attempting to transmit sidelink communication after performing the LBT procedure based at least in part on a result of an LBT procedure.

[0225] Aspect 25 includes a method according to aspect 24, wherein when the second UE reserves the first transmission starting point, the attempting the transmission from the first transmission starting point and the remaining transmission starting points of the one or more transmission starting points is prohibited.

[0226] Aspect 26 includes a method according to any one of Aspects 24 to 25, wherein when the second UE retains the first transmission starting point, the attempt to transmit is moved to a second transmission starting point among the one or more transmission starting points, wherein the second transmission starting point is after the first transmission starting point.

[0227] Aspect 27 includes a method according to any one of aspects 24 to 26, wherein the sending is performed by the first UE when the first UE does not detect that the second UE accesses the first sending starting point.

[0228] Aspect 28 includes a method according to any one of Aspects 24 to 27, wherein when the second UE retains the first transmission starting point and the first UE is not the target recipient of the second UE retaining the first transmission starting point, the attempt to transmit is moved to a second transmission starting point among the one or more transmission starting points, wherein the second transmission starting point is after the first transmission starting point.

[0229] Aspect 29 includes a method according to any one of Aspects 24 to 28, wherein when the second UE retains the first transmission starting point and the sidelink communication is not unicast to the second UE, the transmission of the sidelink communication is performed by the first UE at the first transmission starting point in frequency division multiplexing (FDM).

[0230] Aspect 30 includes a method according to any one of aspects 24 to 29, wherein the sidelink communication is one of a multicast of a broadcast to a plurality of UEs.

[0231] Aspect 31 includes a method according to any one of Aspects 24 to 30, wherein when the second UE reserves the first transmission start point for one or more target recipients other than the first UE and the sidelink communication is not unicast to the second UE, the transmission of the sidelink communication is performed by the first UE at the first transmission start point with frequency division multiplexing (FDM).

[0232] Aspect 32 includes a non-transitory computer-readable medium storing one or more instructions for wireless communication, wherein the one or more instructions include one or more instructions that, when executed individually or collectively by one or more processors of a UE, cause the UE to perform any one of aspects 1 to 18.

[0233] Aspect 33 includes a non-transitory computer-readable medium storing one or more instructions for wireless communication, wherein the one or more instructions include one or more instructions that, when executed individually or collectively by one or more processors of the UE, cause the UE to perform any one of aspects 19 to 23.

[0234] Aspect 34 includes a non-transitory computer-readable medium storing one or more instructions for wireless communication, wherein the one or more instructions include one or more instructions that, when executed individually or collectively by one or more processors of the UE, cause the UE to perform any one of aspects 24 to 31.

[0235] Aspect 35 comprises a user equipment (UE) comprising one or more components for performing any one or more of aspects 1-18.

[0236] Aspect 36 comprises a user equipment (UE) comprising one or more components for performing any one or more of aspects 19-23.

[0237] Aspect 37 comprises a user equipment (UE) comprising one or more components for performing any one or more of aspects 24 to 31.

[0238] Aspect 38 includes a user equipment (UE) comprising one or more components for performing any one or more of aspects 1-18.

[0239] Aspect 39 comprises a user equipment (UE) comprising one or more components for performing any one or more of aspects 19-23.

[0240] Aspect 40 comprises a user equipment (UE) comprising one or more components for performing any one or more of aspects 24 to 31 .

[0241] Information and signals 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 mentioned throughout the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof.

[0242] The various illustrative blocks and modules described in conjunction with the disclosure herein may be implemented or executed using a general purpose processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in an alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

[0243] 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 as one or more instructions or codes on a computer-readable medium, or sent via a computer-readable medium. Other examples and specific implementations are within the scope of the present disclosure and the appended claims. For example, due to the nature of software, the functions described above may be implemented using software executed by a processor, hardware, firmware, hard wiring, or any combination thereof. The features that implement the functions may also be physically located at different locations, including being distributed so that the various parts of the functions are implemented at different physical locations. In addition, as used herein (including in the claims), "or" as used in a list of items (e.g., followed by a list of items such as "at least one of" or "one or more of") indicates an inclusive list, so that, for example, a list of [at least one of A, B, or C] means: A or B or C or AB or AC or BC or ABC (i.e., A and B and C).

[0244] As those skilled in the art will now appreciate and depending on the specific application at hand, many modifications, substitutions and changes may be made to the materials, devices, configurations and methods of use of the apparatus of the present disclosure without departing from the spirit and scope of the present disclosure. In view of this, the scope of the present disclosure should not be limited to the scope of the specific examples illustrated and described herein (as they are only some examples thereof), but should be fully equivalent to the claims appended hereto and their functional equivalents.

Claims

1. A user equipment (UE), the user equipment (UE) comprising: Memory; Transceiver; as well as One or more processors, the one or more processors being coupled to the memory and the transceiver, the memory comprising instructions executable by the one or more processors, individually or collectively, to cause the UE to: Implementing Listen Before Talk (LBT) protocols; Based on the success of the LBT procedure, obtaining a channel occupation time (COT); sending a sidelink message to a second UE during the COT, for notifying the second UE of a shared portion of the COT; Obtaining a first sending start point among one or more sending start points within the remaining portion of the COT; as well as The side link communication is transmitted within the COT after the acquisition of the first transmission start point. 2 . The UE according to claim 1 , wherein the acquiring of the first transmission starting point among the one or more transmission starting points is within the shared portion of the COT. 3 . The UE according to claim 1 , wherein the acquiring the first transmission starting point among the one or more transmission starting points comprises performing a channel access procedure. 4 . The UE of claim 3 , wherein the type of the channel access procedure is based on a gap between the first transmission start point of the one or more transmission start points and an end of a previous transmission in the COT. The UE of claim 4 , wherein the previous transmission is a most recent transmission from the first UE. The UE of claim 4 , wherein the previous transmission is a most recent transmission from the second UE. 7 . The UE according to claim 3 , wherein the first UE has a higher priority than the second UE in acquiring the first transmission starting point among the one or more transmission starting points. 8 . The UE of claim 7 , wherein the first UE has a higher priority than the second UE based on a channel access priority class (CAPC).

9. The UE of claim 7, wherein the first UE has priority over the second UE based on an L-1 priority of the sidelink communication.

10. The UE of claim 1, wherein the acquiring the first transmission start point of the one or more transmission start points within the remaining portion of the COT is based at least in part on any gap between any two transmissions within the COT being less than a predefined value. The UE of claim 1 , wherein the first transmission starting point is reserved for the first UE. 12 . The UE according to claim 11 , wherein the first transmission starting point is an initial transmission starting point among the one or more transmission starting points.

13. The UE according to claim 1, wherein the acquiring the first transmission starting point is achieved via cyclic prefix extension.

14. The UE of claim 1, wherein the sending the sidelink message comprises sending an indication of the one or more transmission start points.

15. A user equipment (UE), the user equipment (UE) comprising: Memory; Transceiver; as well as One or more processors, the one or more processors being coupled to the memory and the transceiver, the memory comprising instructions executable by the one or more processors, individually or collectively, to cause the UE to: receiving a sidelink message from a second UE indicating a shared portion of a channel occupancy time (COT); selecting a first sending start point from among the one or more sending start points within the COT based on a reservation status of the first sending start point; as well as Based at least in part on the results of the LBT procedure, transmission of a sidelink communication is attempted after performing the LBT procedure. 16 . The UE according to claim 15 , wherein when the second UE reserves the first transmission starting point, the attempting the transmission from the first transmission starting point and the remaining transmission starting points of the one or more transmission starting points is prohibited.

17. The UE of claim 15, wherein when the second UE retains the first transmission starting point, the attempt to transmit is moved to a second transmission starting point among the one or more transmission starting points, wherein the second transmission starting point is after the first transmission starting point.

18. The UE of claim 15, wherein the transmission of the sidelink communication is performed by the first UE at the first transmission starting point when the second UE retains the first transmission starting point and the sidelink communication is not unicast to the second UE. 19 . The UE of claim 18 , wherein the transmission of the sidelink communication is performed by the first UE in frequency division multiplexing (FDM) at the first transmission start point.

20. The UE of claim 18, wherein the sidelink communication is one of a multicast of a broadcast to a plurality of UEs.

21. A method of wireless communication performed by a first user equipment (UE), the method comprising: Implementing Listen Before Talk (LBT) protocols; Based on the success of the LBT procedure, obtaining a channel occupation time (COT); sending a sidelink message to a second UE during the COT, for notifying the second UE of a shared portion of the COT; Obtaining a first sending start point among one or more sending start points within the remaining portion of the COT; as well as The side link communication is transmitted within the COT after the acquisition of the first transmission start point.

22. The method of claim 21, wherein the acquiring the first of the one or more transmission starting points comprises performing a channel access procedure.

23. The method of claim 22, wherein the type of the channel access procedure is based on a gap between the first of the one or more transmission start points and an end of a previous transmission in the COT.

24. The method of claim 23, wherein the previous transmission is a most recent transmission from the first UE.

25. The method of claim 23, wherein the previous transmission is a most recent transmission from the second UE. 26 . The method according to claim 22 , wherein the first UE has a higher priority than the second UE in acquiring the first transmission starting point among the one or more transmission starting points.

27. The method of claim 21, wherein the obtaining the first transmission start point of the one or more transmission start points within the remaining portion of the COT is based at least in part on any gap between any two transmissions within the COT being less than a predefined value.

28. A method of wireless communication performed by a first user equipment (UE), the method comprising: receiving a sidelink message from a second UE indicating a shared portion of a channel occupancy time (COT); selecting a first sending start point from among the one or more sending start points within the COT based on a reservation status of the first sending start point; as well as Based at least in part on the results of the LBT procedure, transmission of a sidelink communication is attempted after performing the LBT procedure.

29. The method according to claim 28, wherein when the second UE reserves the first transmission starting point, the attempting the transmission from the first transmission starting point and the remaining transmission starting points of the one or more transmission starting points is prohibited.

30. The method of claim 28, wherein when the second UE retains the first transmission starting point, the attempt to transmit is moved to a second transmission starting point among the one or more transmission starting points, wherein the second transmission starting point is after the first transmission starting point.

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