Channel occupancy time (COT) maintenance for sidelink communications in unlicensed frequency bands

Abstract

A method of wireless communication performed by a first wireless communication device can maintain a channel occupancy time (COT) in a shared frequency band during at least one physical sidelink feedback channel (PSFCH) instance. In some aspects, the method includes transmitting, in a first portion of a COT based on listen-before-talk (LBT), a first sidelink (SL) communication including a sidelink (SL) communication information (SCI) indicating that a second wireless communication device transmits a signal in at least one gap symbol prior to a PSFCH resource. The method also includes receiving the signal from the second wireless communication device during the at least one gap symbol. The method also includes transmitting a second SL communication in a second portion of the COT based on the LBT, wherein the second portion of the COT is subsequent to the PSFCH resource.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of U.S. Patent Application No. 17 / 740,059, filed on May 9, 2022, the disclosure of which is incorporated herein by reference in its entirety as if fully set forth below and for all applicable purposes. Background Art

[0003] 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 be otherwise referred to as user equipment (UE).

[0004] In order to meet the growing demand for extended mobile broadband connections, wireless communication technology is evolving from long term evolution (LTE) technology to next generation new radio (NR) technology, which may be referred to as the fifth generation (5G). For example, NR is designed to provide lower latency, higher bandwidth or higher throughput, and higher reliability compared to LTE. NR is designed to operate on a wide spectrum band array, for example, from low frequency bands below about 1 gigahertz (GHz) and mid-frequency bands from about 1 GHz to about 6 GHz to high frequency 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.

[0005] In a wireless communication network, a BS can communicate with a UE in both the uplink and downlink directions. Sidelinks were introduced in LTE to allow a UE to transmit data to another UE without tunneling through the BS and / or associated core network. LTE sidelink technology has been extended to provide device-to-device (D2D) communications, vehicle-to-everything (V2X) communications, and / or cellular vehicle-to-everything (C-V2X) communications. Similarly, NR can be extended to support sidelink communications of D2D, V2X, and / or C-V2X on dedicated spectrum, licensed spectrum, and / or unlicensed spectrum. Summary of the invention

[0006] 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 expected features of the present disclosure, and is neither intended to identify 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.

[0007] According to one aspect of the present disclosure, a method of wireless communication performed by a first wireless communication device includes: sending a first SL communication including sidelink (SL) communication information (SCI) in a first part of a channel occupancy time (COT) based on listen-before-talk (LBT), the SCI indicating that a second wireless communication device sends a signal in at least one gap symbol before a physical sidelink feedback channel (PSFCH) resource; receiving the signal from the second wireless communication device during the at least one gap symbol; and sending a second SL communication in a second part of the COT based on the LBT, wherein the second part of the COT is after the PSFCH resource.

[0008] According to another aspect of the present disclosure, a method of wireless communication performed by a first wireless communication device includes: performing listen before talk (LBT) to initiate a channel occupation time (COT); and sending a first side link (SL) communication in the COT based on the LBT, the first SL communication including SL communication information (SCI) and SL data, the COT including SL data resources and SL feedback resources, wherein the SL data is rate matched to occupy at least a portion of the SL feedback resources and the SL data resources.

[0009] According to another aspect of the present disclosure, a first wireless communication device includes: a memory; a transceiver; and a processor communicating with the memory and the transceiver, wherein the first wireless communication device is configured to: send a first SL communication including sidelink (SL) communication information (SCI) in a first part of a channel occupancy time (COT) based on listen-before-talk (LBT), the SCI indicating that a second wireless communication device sends a signal in at least one gap symbol before a physical sidelink feedback channel (PSFCH) resource; receive the signal from the second wireless communication device during the at least one gap symbol; and send a second SL communication in a second part of the COT based on the LBT, wherein the second part of the COT is after the PSFCH resource.

[0010] According to another aspect of the present disclosure, a first wireless communication device includes: a memory; a transceiver; and a processor communicating with the memory and the transceiver, wherein the first wireless communication device is configured to: perform listen before talk (LBT) to initiate a channel occupation time (COT); and send a first side link (SL) communication in the COT based on the LBT, the first SL communication including SL communication information (SCI) and SL data, the COT including SL data resources and SL feedback resources, wherein the SL data is rate matched to occupy at least a portion of the SL feedback resources and the SL data resources.

[0011] According to another aspect of the present disclosure, a non-transitory computer-readable medium includes a program code recorded thereon, wherein the program code includes instructions capable of being executed by a processor of a first wireless communication device to enable the first wireless communication device to perform the following operations: sending a first SL communication including sidelink (SL) communication information (SCI) in a first part of a channel occupancy time (COT) based on listen-before-talk (LBT), the SCI indicating that a second wireless communication device sends a signal in at least one gap symbol before a physical sidelink feedback channel (PSFCH) resource; receiving the signal from the second wireless communication device during the at least one gap symbol; and sending a second SL communication in a second part of the COT based on the LBT, wherein the second part of the COT is after the PSFCH resource.

[0012] According to another aspect of the present disclosure, a non-transitory computer-readable medium includes a program code recorded thereon, wherein the program code includes instructions capable of being executed by a processor of a first wireless communication device to enable the first wireless communication device to perform the following operations: perform listen before talk (LBT) to initiate a channel occupation time (COT); and send a first side link (SL) communication in the COT based on the LBT, the first SL communication including SL communication information (SCI) and SL data, the COT including SL data resources and SL feedback resources, wherein the SL data is rate matched to occupy at least a portion of the SL feedback resources and the SL data resources.

[0013] According to another aspect of the present disclosure, a first wireless communication device includes: a component for sending a first SL communication including sidelink (SL) communication information (SCI) in a first part of a channel occupancy time (COT) based on listen-before-talk (LBT), the SCI indicating that a second wireless communication device sends a signal in at least one gap symbol before a physical sidelink feedback channel (PSFCH) resource; a component for receiving the signal from the second wireless communication device during the at least one gap symbol; and a component for sending a second SL communication in a second part of the COT based on the LBT, wherein the second part of the COT is after the PSFCH resource.

[0014] According to another aspect of the present disclosure, a first wireless communication device includes: a component for performing listen-before-talk (LBT) to initiate a channel occupation time (COT); and a component for sending a first side link (SL) communication in the COT based on the LBT, the first SL communication including SL communication information (SCI) and SL data, the COT including SL data resources and SL feedback resources, wherein the SL data is rate matched to occupy at least a portion of the SL feedback resources and the SL data resources.

[0015] After reviewing the following description of specific, exemplary embodiments of the present invention in conjunction with the accompanying drawings, other aspects, features, and embodiments of the present invention will become apparent to those of ordinary skill in the art. Although the various features of the present invention may be discussed with respect to certain embodiments and drawings below, all embodiments of the present invention may include one or more of the advantageous features discussed herein. In other words, although one or more embodiments may be discussed as having certain advantageous features, one or more of these features may also be used in accordance with the various embodiments of the present invention discussed herein. In a similar manner, although the exemplary embodiments may be discussed below as device, system, or method embodiments, it should be understood that these exemplary embodiments 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 A wireless communication network providing sidelink communications according to some aspects of the present disclosure is illustrated.

[0018] Figure 3 A sidelink communication scheme in a wireless communication network according to some aspects of the present disclosure is illustrated.

[0019] Figure 4 is a timing diagram illustrating a side link communication scenario according to some aspects of the present disclosure.

[0020] Figure 5 is a timing diagram illustrating a scheme for maintaining a channel occupancy time (COT) for sidelink communications in a shared frequency band according to aspects of the present disclosure.

[0021] Figure 6 is a signaling diagram illustrating a method for maintaining COT for sidelink communications in a shared frequency band according to aspects of the present disclosure.

[0022] Figure 7is a flow chart illustrating a scheme for maintaining COT for sidelink communications in a shared frequency band according to aspects of the present disclosure.

[0023] Figure 8 is a signaling diagram illustrating a method for maintaining COT for sidelink communications in a shared frequency band according to aspects of the present disclosure.

[0024] Fig.9A is a timing diagram illustrating a side link communication scenario according to some aspects of the present disclosure.

[0025] Fig. 9B is a timing diagram illustrating a scheme for maintaining COT for sidelink communications in a shared frequency band according to aspects of the present disclosure.

[0026] Fig.10 is a block diagram of a user equipment (UE) according to some aspects of the present disclosure.

[0027] Fig.11 is a block diagram of an exemplary base station (BS) according to some aspects of the present disclosure.

[0028] Fig.12 is a flow chart of a sidelink communication method according to some aspects of the present disclosure.

[0029] Fig.13 is a flow chart of a sidelink 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 aspects, various technologies 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, global mobile communication systems (GSM) networks, fifth 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 network can realize radio technology 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 GSM are part of Universal Mobile Telecommunications System (UMTS). Specifically, Long Term Evolution (LTE) is a UMTS version using 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 known or under development. For example, the 3rd Generation Partnership Project (3GPP) is a collaboration between telecommunication association groups 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 UMTS mobile phone standards. 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] 5G networks are expected to have diverse deployments, diverse spectrum, and diverse 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 being 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 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 extremely high capacity (e.g., on the order of 10Tbps / km 2 ), extremely high data rates (e.g., multi-Gbps rates, 100+Mbps user experience 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 effectively 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 may appear at 15kHz on bandwidths (BW) such as 5MHz, 10MHz, 20MHz, etc. For other various outdoor and small cell coverage deployments of TDD greater than 3GHz, the subcarrier spacing may appear at 30kHz on 80 / 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 UL / downlink scheduling information, data, and acknowledgment in the same subframe. The self-contained integrated subframe supports communications in unlicensed or contention-based shared spectrum, adaptive UL / downlink (which can be flexibly configured on a per-cell basis to dynamically switch between UL 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] Sidelink communication refers to communication between user equipment devices (UE) without tunneling base stations (BS) and / or core networks. Sidelink communication can be communicated on physical sidelink control channels (PSCCH) and physical sidelink shared channels (PSSCH). PSCCH and PSSCH are similar to physical downlink control channels (PDCCH) and physical downlink shared channels (PDSCH) in downlink (DL) communication between BS and UE. For example, PSCCH may carry sidelink control information (SCI) and PSSCH may carry sidelink data (e.g., user data). Each PSCCH is associated with a corresponding PSSCH, wherein the SCI in the PSCCH may carry reservation and / or scheduling information for sidelink data transmission in the associated PSSCH. Use cases for sidelink communication may include vehicle-to-everything (V2X), industrial IoT (IIot) and / or NR-lightweight.

[0038] A UE communicating using a side link interface may be configured to respond to side link communications from other UEs using a hybrid automatic repeat request (HARQ) feedback indicating whether one or more side link transport blocks (TBs) have been successfully received. In some aspects, the UE may be configured with a side link feedback resource mapped to one or more SL data resources. For example, the UE may be configured with a physical side link feedback channel (PSFCH) resource. The PSFCH resource may include one or more periodic PSFCH instances. Each PSFCH instance may be associated with a PSFCH period including one or more time slots. In some aspects, the UE may communicate at least one PSSCH communication in each time slot. In addition, the UE may be configured to communicate using shared or unlicensed frequency resources. These communications may be referred to as side link unlicensed (SL-U). In order to communicate in shared or unlicensed frequency resources, one or more UEs may perform a clear channel assessment (CCA). For example, the UE may perform a listen-before-talk (LBT) procedure by obtaining a channel measurement of a fixed or variable amount of time. If the channel measurement is below a configured threshold, the UE may initiate or obtain a channel occupancy time (COT) to communicate with one or more other UEs. In some aspects, communication from one UE to another specific UE may be referred to as unicast communication. Communication from one or more UEs to one or more other UEs may be referred to as groupcast or multicast communication.

[0039] Each acquired COT may provide a limited amount of time to send and / or receive SL communications. For example, each COT may include one or more time slots, each of which includes multiple symbols allocated for different types of SL signals and / or data. For example, each time slot may include one or more portions allocated for SCI and one or more portions allocated for SL data. In addition, the UE may be configured with a periodic PSFCH resource, which may have a periodicity of one time slot or more than one time slot. In some aspects, the UE may be configured with one or more gap symbols between the SL data portion and the PSFCH resource. In this regard, in some aspects, conveying PSFCH information may involve switching in the link direction (e.g., sending to receiving, receiving to sending). However, wireless communication devices using shared or unlicensed frequency resources may operate based on continuity requirements during the COT. For example, if the UE suppresses communication during the COT for more than a configured duration, the UE may be prevented from continuing to communicate in the COT after the gap. In some instances, the configured duration may be approximately 16 microseconds (μs). In other instances, the configured duration may be approximately 25μs. However, the duration of a single symbol may be greater than 25 μs.Therefore, if the PSFCH resource includes configured gap symbols and the PSFCH resource is scheduled in the middle of a COT where there is a burst of SL transmission and / or reception, the UE may be prevented from continuing to communicate in the COT after the PSFCH instance.

[0040] The present disclosure provides systems, schemes, and mechanisms for maintaining COT for sidelink communications in a shared frequency band. In some aspects, the mechanism for maintaining COT includes a first wireless communication device instructing a second wireless communication device to send a signal in at least one symbol between a sidelink communication channel and a sidelink feedback instance. In some aspects, the sidelink feedback instance may be a PSFCH instance. In some aspects, the signal may include a cyclic prefix (CP). On the other hand, the signal may include an extension of the CP. The extension may be referred to as a CP extension (CPE). In some aspects, sending a signal may include sending a sidelink ACK / NACK in a PSFCH instance, wherein the CPE is at least partially extended within at least one gap symbol. The second wireless communication device may send a signal in at least one gap symbol so that the remaining gap between the PSSCH communication and the PSFCH communication is less than 25 μs. On the other hand, the second wireless communication device may send a signal so that the gap between the PSSCH and the PSFCH is less than about 16 μs. According to another aspect of the present disclosure, the first wireless communication device may instruct the second wireless communication device to send a fill signal or a pattern signal in at least one PSF viewing instance. For example, in some instances, the first wireless communication device may not expect to receive PSFCH communications from the second wireless communication device. In addition, the first wireless communication device may not have sidelink feedback data for communicating in the PSFCH instance. Therefore, the first wireless communication device may instruct the second wireless communication device to send a fill signal, wherein the fill signal is based on the PSFCH waveform. In some aspects, sending the fill signal may include sending a CPE with a fill signal based on the PSFCH. In some aspects, the CPE may be sent in at least one gap symbol between the PSSCH instance and the PSFCH instance. According to another aspect of the present disclosure, a mechanism for maintaining COT may include rate matching the sidelink data to be spread over at least one gap symbol and / or PSFCH instance.

[0041] According to another aspect of the present disclosure, the first wireless communication device may rate match the sidelink communication to extend at least partially on the PSFCH resource. For example, the first wireless communication device may be configured to rate match the PSSCH communication to extend on at least one slot symbol, at least one AGC symbol, and / or at least one PSFCH symbol, such that the gap between the end of the rate-matched first SL communication and the beginning of the second SL communication in the subsequent time slot is less than the configured COT maintenance threshold.

[0042] Various aspects of the present disclosure may provide several benefits. For example, by allowing multiple mechanisms for closing gap periods associated with PSFCH resources, one or more UEs communicating in a sidelink network may utilize a larger portion of the acquired COT to more efficiently use shared frequency resources. In addition, by facilitating more continuous sidelink communications in shared frequency resources, the chance of conflicts and / or interference may be reduced. As a result, error rates may also be reduced, which may increase network speeds and reduce overhead, thereby improving user experience. Although the present disclosure is described in the context of deploying autonomous sidelink communications on a 2.4 GHz unlicensed band, the disclosed aspects may be applicable to any suitable shared or unlicensed band.

[0043] Figure 1 A wireless communication network 100 according to some aspects of the present disclosure is illustrated. The network 100 may be a 5G network. The network 100 includes several base stations (BSs) 105 (respectively labeled 105a, 105b, 105c, 105d, 105e, and 105f) and other network entities. The BS 105 may be a station that communicates with the UE 115, and may also be referred to as an evolved Node B (eNB), a next generation eNB (gNB), an access point, and the like. Each BS 105 may provide communication coverage for a particular geographic area. In 3GPP, the term "cell" may refer to the particular geographic coverage area of ​​the BS 105 and / or the BS subsystem serving the coverage area, depending on the context in which the term is used.

[0044] BS105 may provide communication coverage for macro cells or small cells (such as pico cells or femto cells) and / or other types of cells. Macro cells generally cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions with a network provider. Small cells (such as pico cells) will generally cover a relatively small geographic area and may allow unrestricted access by UEs with service subscriptions with a network provider. Small cells (such as femto cells) will generally also cover a relatively small geographic area (e.g., a home) and, in addition to unrestricted access, may also provide restricted access by UEs associated with the femto cells (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, BS105d and 105e may be conventional macro BSs, while BS 105a-105c may be macro BSs with one of three-dimensional (3D), full-dimensional (FD) or massive MIMO capabilities. BS105a-105c may utilize its higher-dimensional MIMO capabilities to employ 3D beamforming in both elevation and azimuth beamforming to increase coverage and capacity. BS105f 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.

[0045] 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.

[0046] UE 115 is dispersed throughout the wireless network 100, and each UE 115 can 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). On the other hand, 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 UE 115 and a serving BS 105 (which is a BS designated to provide service to UE 115 on a downlink (DL) and / or uplink (UL), desired transmission between BSs 105, backhaul transmission between BSs, or sidelink transmission between UE 115.

[0047] 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-105c and small cell BS 105f. Macro BS 105d also sends 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.

[0048] The BSs 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., which may be examples of gNBs or access node controllers (ANCs)) may interface with the core network via a backhaul link (e.g., NG-C, NG-U, etc.), and may perform wireless configuration and scheduling for communications 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.

[0049] 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 drone. The redundant communication links with UE 115e may include links from macro BSs 105d and 105e, and links from 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 BSs such as small cell BS 105f and macro BS 105e through the network 100, or communicate through the network in a multi-step configuration by communicating with another user device, such as UE 115f, which communicates temperature measurement information to a smart meter (UE 115g), which then reports to the network through the small cell BS 105f, which relays its information to the network. The network 100 may also provide additional network efficiency through dynamic low latency TDD / FDD communications, such as V2V, V2X, C-V2X communications between UE 115i, 115j, or 115k and other UEs 115 and / or vehicle-to-infrastructure (V2I) communications between UE 115i, 115j, or 115k and BS 105.

[0050] 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.

[0051] In some aspects, BS105 may assign or schedule transmission resources (e.g., in the form of time-frequency resource blocks (RBs)) for downlink (DL) and uplink (UL) transmissions in network 100. DL refers to the transmission direction from BS105 to UE 115, and UL refers to the transmission direction from UE 115 to BS105. The communication may be in the form of a radio frame. A radio frame may be divided into a plurality of subframes or time slots, for example, about 10. 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., a DL subframe) in a radio frame may be used for DL ​​transmission, and another subframe subset (e.g., an UL subframe) in a radio frame may be used for UL transmission.

[0052] 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 BS105 and UE 115. For example, a reference signal may have a specific pilot pattern or structure, wherein a pilot tone may span an operational BW or frequency band, and each pilot tone may be located at a predefined time and a predefined frequency. For example, BS105 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 BS105 to estimate an UL channel. Control information may include resource assignments and protocol control. Data may include protocol data and / or operational data. In some aspects, BS105 and UE115 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.

[0053] In some aspects, the network 100 may be an NR network deployed on a licensed spectrum. The BS 105 may send 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 system information (RMSI), and other system information (OSI)) to facilitate initial network access. In some cases, the BS 105 may broadcast the PSS, SSS, and / or MIB in the form of a synchronization signal block (SSB) over a physical broadcast channel (PBCH), and may broadcast the RMSI and / or OSI over a physical downlink shared channel (PDSCH).

[0054] In some aspects, a UE 115 attempting to access the network 100 may perform an initial cell search by detecting a 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 a cell. The PSS and SSS may be located in the center portion of a carrier or at any suitable frequency within a carrier.

[0055] 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 UL control channel (PUCCH), physical UL shared channel (PUSCH), power control, and SRS.

[0056] 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. In some examples, the random access procedure may be a four-step random access procedure. For example, the UE 115 may send a random access preamble, and the BS 105 may respond with a random access response. The random access response (RAR) may include a detected random access preamble identifier (ID) corresponding to the random access preamble, timing advance (TA) information, UL grant, temporary cell radio network temporary identifier (C-RNTI), and / or a backoff indicator. 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. The connection response may indicate contention resolution. In some examples, the random access preamble, the RAR, the connection request, and the connection response may be referred to as message 1 (MSG1), message 2 (MSG2), message 3 (MSG3), and message 4 (MSG4), respectively. In some examples, the random access procedure may be a two-step random access procedure, where the UE 115 may send a random access preamble and a connection request in a single transmission, and the BS 105 may respond by sending a random access response and a connection response in a single transmission.

[0057] After establishing the connection, 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 scheduling grant may be sent in the form of DL control information (DCI). The BS 105 may send a DL communication signal (e.g., carrying data) 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.

[0058] In some aspects, BS105 may communicate with UE 115 using HARQ technology to improve communication reliability, for example, to provide URLLC services. BS105 may schedule UE 115 for PDSCH communication by sending DL grants in PDCCH. BS105 may send DL data packets to UE 115 according to the scheduling in PDSCH. DL data packets may be sent in the form of transport blocks (TBs). If UE 115 successfully receives the DL data packet, UE 115 may send HARQ ACK to BS105. On the contrary, if UE 115 fails to successfully receive the DL transmission, UE 115 may send HARQ NACK to BS105. Once HARQ NACK is received from UE115, BS105 may resend the DL data packet to UE 115. Retransmission may include a decoded version of the DL data that is the same as the initial transmission. Alternatively, retransmission may include a decoded version of the DL data that is different from the initial transmission. The UE 115 may apply soft combining to combine the coded data received from the initial transmission and the retransmission for decoding. The BS 105 and the UE 115 may also apply HARQ to UL communications using a substantially similar mechanism as DL HARQ.

[0059] In some aspects, the network 100 may operate on a system BW or a component carrier (CC) BW. The network 100 may divide the system BW into multiple BWPs (e.g., parts). The BS 105 may dynamically assign the UE 115 to operate on a specific BWP (e.g., a specific part of the system BW). The assigned BWP may be referred to as an active BWP. The UE 115 may monitor the active BWP to find signaling information from the BS 105. The BS 105 may schedule the UE 115 to perform UL or DL ​​communications in the active BWP. In some aspects, the BS 105 may assign a pair of BWPs within the CC to the UE 115 for UL and DL communications. For example, the BWP pair may include a BWP for UL communication and a BWP for DL ​​communication.

[0060] In some aspects, network 100 may operate on a shared channel, which may include a shared frequency band and / or an unlicensed frequency band. For example, network 100 may be an NR-U network operating on an unlicensed frequency band. In such aspects, BS105 and UE115 may be operated by multiple network operation entities. In order to avoid conflicts, BS105 and UE 115 may use a listen-before-talk (LBT) procedure to monitor a transmit opportunity (TXOP) in a shared channel. TXOP may also be referred to as COT. For example, a transmitting node (e.g., BS105 or UE 115) may perform LBT before transmitting in a channel. When LBT passes, the transmitting node may continue to transmit. When LBT fails, the transmitting node may suppress transmission in the channel.

[0061] LBT may be based on energy detection (ED) or signal detection. For LBT based on energy detection, when the signal energy measured from the channel is lower than a threshold, the result of LBT is passed. Conversely, when the signal energy measured from the channel exceeds a threshold, the result of LBT is a failure. For LBT based on signal detection, when a channel reservation signal (e.g., a predetermined preamble signal) is not detected in the channel, the result of LBT is passed. In addition, LBT may be in a variety of modes. The LBT mode may be, for example, type 4 (CAT4) LBT, type 2 (CAT2) LBT, or type 1 (CAT1) LBT. CAT1 LBT is referred to as a no-LBT mode, in which no LBT is performed before transmission. CAT2 LBT refers to LBT without a random backoff period. For example, a transmitting node may determine a channel measurement in a time interval and determine whether a channel is available based on a comparison of the channel measurement with an ED threshold. CAT4 LBT refers to an LBT with a random backoff and a variable contention window (CW). For example, a transmitting node may extract a random number and back off a duration in a certain time unit based on the extracted random number in a certain time unit.

[0062] In some aspects, the network 100 can support sidelink communications between UEs 115 on a shared radio frequency band (e.g., in a shared spectrum or an unlicensed spectrum). In some aspects, the UEs 115 can communicate with each other on a 2.4 GHz unlicensed band that can be shared by multiple network operating entities using various radio access technologies (RATs) such as NR-U, WiFi, and / or License Assisted Access (LAA), such as NR-U. Figure 2 shown.

[0063] Figure 2 An example of a wireless communication network 200 providing side link communication according to aspects of the present disclosure is illustrated. The network 200 may correspond to a portion of the network 100. To simplify the discussion, Figure 2Two BSs 205 (shown as 205a and 205b) and six UEs 215 (shown as 215a1, 215a2, 215a3, 215a4, 215b1, and 215b2) are illustrated, but it should be appreciated that aspects of the present disclosure can be extended to any suitable number of UEs 215 (e.g., about 2, 3, 4, 5, 7, or more) and / or BSs 205 (e.g., about 1, 3, or more). BSs 205 and UEs 215 can be similar to BSs 105 and UEs 115, respectively. BSs 205 and UEs 215 can share the same radio frequency band for communication. In some instances, the radio frequency band can be a 2.4 GHz unlicensed band, a 5 GHz unlicensed band, or a 6 GHz unlicensed band. In general, the shared radio frequency band can be at any suitable frequency.

[0064] BS205a and UE 215a1-215a4 may be operated by a first network operating entity. BS205b and UE 215b1-215b2 may be operated by a second network operating entity. In some aspects, the first network operating entity may use the same RAT as the second network operating entity. For example, BS205a and UE 215a1-215a4 of the first network operating entity and BS205b and UE 215b1-215b2 of the second network operating entity are NR-U devices. In some other aspects, the first network operating entity may use a different RAT from the second network operating entity. For example, BS205a and UE 215a1-215a4 of the first network operating entity may utilize NR-U technology, while BS205b and UE 215b1-215b2 of the second network operating entity may utilize WiFi or LAA technology.

[0065] In network 200, some UEs in UE 215a1-215a4 can communicate with each other in peer-to-peer communication. For example, UE 215a1 can communicate with UE 215a2 through side link 252, UE 215a3 can communicate with UE 215a4 through another side link 251, and UE 215b1 can communicate with UE 215b2 through another side link 254. Side links 251, 252 and 254 are unicast bidirectional links. Some UEs in UE 215 can also communicate with BS 205a or BS 205b in UL direction and / or DL ​​direction via communication link 253. For example, UE 215a1, 215a3 and 215a4 are in the coverage area 210 of BS 205a, and therefore can communicate with BS 205a. UE 215a2 is outside the coverage area 210, and therefore can not communicate directly with BS 205a. In some instances, UE 215a1 may operate as a repeater for UE 215a2 to reach BS 205a. Similarly, UE 215b1 is within the coverage area 212 of BS 205b, and therefore may communicate with BS 205b, and may operate as a repeater for UE 215b2 to reach BS 205b. In some aspects, some of UEs 215 are associated with vehicles (e.g., similar to UEs 115i-115k), and the communications conducted through side links 251, 252, and 254 may be C-V2X communications. C-V2X communications may refer to communications between a vehicle and any other wireless communication device in a cellular network.

[0066] Figure 3 A sidelink communication scheme 300 in a wireless communication network according to some aspects of the present disclosure is illustrated. A UE (such as UE 115 and / or 215) in a network (such as network 100 and / or 200) may employ scheme 300. Specifically, a sidelink UE may employ scheme 300 to contend for access in a shared radio frequency band (e.g., in a shared spectrum or an unlicensed spectrum) for sidelink communication. A shared radio frequency band may be shared by multiple RATs, such as Figure 2 As discussed in Figure 3 , the x-axis represents time in some arbitrary units, and the y-axis represents frequency in some arbitrary units.

[0067] In the scheme 300, a shared radio frequency band 301 is divided into a plurality of sub-channels or frequency sub-bands 302 (shown as 302 S0 ,302 S1 ,302 S2, ...) for side link communication. Frequency band 301 can be at any suitable frequency. In some instances, frequency band 301 is a 2.4 GHz unlicensed band. In some instances, frequency band 301 is a 5 GHz unlicensed band. In some instances, frequency band 301 is a 6 GHz unlicensed band. Frequency band 301 can have any suitable BW and can be divided into any suitable number of frequency sub-bands 302. The number of frequency sub-bands 302 can depend on the side link communication BW requirements. In some aspects, frequency band 301 is a 2.4 GHz unlicensed band and can have a bandwidth of approximately 80 megahertz (MHz) divided into approximately fifteen 5 MHz frequency sub-bands 302.

[0068] A sidelink UE (eg, UE 115 and / or 215) may be equipped with a wideband receiver and a narrowband transmitter. For example, the UE may utilize a narrowband transmitter to access frequency subband 302. S2 , to utilize the frame structure 304 for sidelink transmission. The frame structure 304 is repeated in each frequency subband 302. In some examples, such as Figure 3 As shown in , there may be frequency gaps or guard bands between adjacent frequency sub-bands 302, for example, to mitigate adjacent frequency band interference. Thus, multiple sidelink data may be communicated simultaneously in different frequency sub-bands 302 (e.g., FDM). The frame structure 304 also repeats in time. For example, the frequency sub-bands 302 S2 The time may be divided into multiple frames with a frame structure 304. The frame structure 304 includes an LBT gap duration 310 followed by a sidelink resource 306. The LBT gap duration 310 is used for channel contention between devices of the same RAT or between devices of different RATs. When winning the contention, the sidelink UE may utilize the sidelink resource 306 to send control data and user data.

[0069] The sidelink resources 306 may have a substantially similar structure to the NR sidelink resources. For example, the sidelink resources 306 may include multiple subcarriers or RBs in frequency and multiple symbols in time. In some instances, the sidelink resources 306 may have a duration between about one millisecond (ms) and about 20 ms. The sidelink resources 306 may include a PSCCH 320, a PSSCH 330, and / or a physical sidelink feedback channel (PSFCH) 340. The PSCCH 320, the PSSCH 330, and the PSFCH 340 may be multiplexed in time and / or frequency. Figure 3 In the illustrated example, the PSCCH 320 is located during the beginning symbol (eg, about 1 symbol or about 2 symbols) of the side link resource 306 and occupies the frequency subband 302. S2PSFCH 340 is located at the end symbol of sidelink resource 306. PSSCH 330 occupies the remaining time-frequency resources in sidelink resource 306. In general, PSCCH 320, PSSCH 330 and PSFCH 340 can be multiplexed in sidelink resource 306 in any suitable configuration.

[0070] A sidelink UE (e.g., UE 115 and / or 215) that intends to transmit in frequency band 301 may perform narrowband LBT in one or more frequency subbands 302. For example, the sidelink UE may transmit in frequency subband 302 during LBT gap duration 310. S2 The LBT can be as described above. Figure 1 CAT4 LBT based on energy detection is discussed. If LBT is passed (e.g., when the measured channel signal energy is below the energy detection threshold), the sidelink UE may proceed to send SCI and sidelink data to the peer sidelink UE in the sidelink resource 306. If LBT fails (e.g., when the channel signal energy is above the energy detection threshold), the sidelink UE may refrain from transmitting in the sidelink resource 306. Thus, LBT may operate to detect the frequency subband 302. S2 access or occupancy in the frequency band 301 and promote coexistence with other technologies sharing the frequency band 301.

[0071] The sidelink UE may send SCI in PSCCH 320 and send sidelink data (e.g., user information data) in PSSCH 330. Depending on the sidelink application, the sidelink data may have various forms and types. For example, when the sidelink application is a V2X application, the sidelink data may carry V2X data (e.g., vehicle location information, travel speed and / or direction, vehicle sensing measurements, etc.). Alternatively, when the sidelink application is an IIoT application, the sidelink data may carry IIoT data (e.g., sensor measurements, device measurements, temperature readings, etc.). The sidelink UE may also send HARQ ACK / NACK in PSFCH 340. HARQ ACK / NACK may be feedback for sidelink data received by the sidelink UE in an earlier sidelink resource 306. SCI may indicate a reservation for the next sidelink resource 306. Therefore, an intra-NR sidelink UE (e.g., a UE in the same NR-U sidelink system) may perform SCI sensing to determine whether the sidelink resource 306 is available or occupied for intra-NR sharing. For example, if the NR intra-sidelink UE detects an SCI indicating a reservation for the sidelink resources 306, the NR intra-sidelink UE may refrain from transmitting in the reserved sidelink resources 306. If the NR intra-sidelink UE determines that a reservation for the sidelink resources 306 is not detected, the NR intra-sidelink UE may transmit in the sidelink resources 306. Thus, SCI sensing may help the UE identify the target frequency subband 302 to reserve for sidelink communication and avoid a conflict (e.g., an intra-NR conflict) with another sidelink UE in the NR sidelink system. In some aspects, the intra-RAT sidelink UE may be configured with a sensing window for SCI sensing or monitoring to reduce intra-NR conflicts.

[0072] The SCI may also indicate scheduling information and / or a destination identifier (ID) of a target receiving sidelink UE identifying the next sidelink resource 306. Thus, the sidelink UE may monitor the SCI sent by other sidelink UEs. After detecting the SCI in the sidelink resource 306, the sidelink UE may determine whether the sidelink UE is the target recipient based on the destination ID. If the sidelink UE is the target recipient, the sidelink UE may proceed to receive and decode the sidelink data indicated by the SCI.

[0073] In some aspects, the scheme 300 is used to synchronize sidelink communications. In other words, the sidelink UEs are synchronized in time and aligned in terms of symbol boundaries, sidelink resource boundaries (e.g., the start time of the sidelink resource 306), and LBT gap duration boundaries (e.g., the start time of the LBT gap duration 310). For example, the sidelink UE can perform synchronization in various forms based on the sidelink SSB received from the sidelink UE and / or the NR-U SSB received from the BS (e.g., BS105 and / or 205) when within the coverage of the BS. In some aspects, for example, when within the coverage of the serving BS, the sidelink UEs in the system can be preconfigured with a resource pool 308 in the frequency band 301. The resource pool 308 may include a plurality of sidelink resources 306 arranged as shown in the frame structure 304. The BS may configure the sidelink UE using a resource pool configuration indicating resources in the frequency band 301 and / or sub-band 302, a frame structure 304 (e.g., LBT gap duration 310 and / or side link resources 306), and / or timing information (e.g., LBT gap duration 310 start and end boundaries).

[0074] Figure 4 A sidelink communication scenario 400 in a shared frequency band according to aspects of the present disclosure is illustrated. Scenario 400 may involve a UE (such as UE 115 and / or 215) in a network (such as network 100 and / or 200). Specifically, the sidelink UE may communicate and / or operate according to scenario 400 to contend for access in a shared radio frequency band (e.g., in a shared spectrum or an unlicensed spectrum) for sidelink communication. The shared radio frequency band may be shared by multiple RATs, such as Figure 2 As discussed in Figure 4 , the x-axis represents time in some arbitrary units, and the y-axis represents frequency in some arbitrary units.

[0075] In scenario 400, a UE may communicate using multiple sidelink resources, as discussed similarly above with respect to scheme 300. The sidelink resources may include PSCCH 420, PSSCH 430, and PSFCH 440. Scenario 400 includes sidelink communications in a shared frequency band during a time period including multiple time slots (e.g., 414, 416). The time domain configuration of scenario 400 may include periodic and / or semi-persistent PSFCH resources 440, which include PSFCH instances 442, 444. In some aspects, PSFCH resources 440 may be a global or common configuration for multiple UEs communicating in a cell and / or network. PSFCH resources 440 may be used to send SL feedback information and / or receive SL feedback information. In some aspects, the SL feedback information may include a hybrid automatic repeat request (HARQ) confirmation / negative confirmation (ACK / NACK) for one or more PSSCH instances (such as a first PSSCH 432 and / or a second PSSCH 434). The periodicity of the PSFCH resources 440 may be referred to as a PSFCH period 412. The PSFCH period 412 may have one or more time slots, such as 1, 2, 4, 6, 8 time slots, and / or any other suitable number of time slots. In the illustrated example, the PSFCH period 412 is four time slots. In some aspects, the UE may determine whether there is SL feedback information to be received in the PSFCH resources, or whether there is SL feedback information to be sent in the PSFCH resources.

[0076] The side link resources may be associated with or acquired by the LBT 460. For example, the UE may perform an LBT to acquire a channel occupancy time (COT). If the LBT result is passed, the UE acquires a COT during which the UE communicates in the first PSCCH 422 and the first PSSCH 432. After the first PSSCH 432, the UE may be configured with periodic and / or semi-persistent PSFCH resources or instances 442. In some aspects, the PSFCH instance 442 may result in a link switch and / or communication gap during the first COT. In some aspects, the communication gap may exceed the COT maintenance threshold configured above. Therefore, the UE may suppress transmission and / or reception during a subsequent time slot 414. The UE may then perform a second LBT 462 during a second time slot 416. Based on the second LBT 462, the UE may obtain a COT 464 during which the UE may communicate in the second PSCCH 424, the second PSSCH 434, the third PSCCH 426, and the third PSSCH 436. If the gap between the PSSCH 434 and the PSSCH 436 is equal to or lower than the configured COT maintenance threshold, the UE may continue the COT 464 between the PSSCH 434 and the PSSCH 436 without performing additional LBT. For example, if the gap between the sidelink communications is less than 25 μs, the UE may continue to communicate during the COT 464. In another example, if the gap between the sidelink communications is equal to or less than 16 μs, the UE may continue to communicate during the COT 464.

[0077] The PSFCH resource 440 includes a second PSFCH instance 444 after the third PSSCH 436. In some aspects, there may be a gap between the third PSSCH 436 and the second PSFCH instance 444. In some aspects, the gap may be greater than 16 μs, or greater than 25 μs. If the gap exceeds 25 μs, the UE may be instructed or configured to perform additional LBT to continue communicating during the COT 464. On the other hand, the UE may perform additional LBT to acquire or initiate a new COT before the sidelink communication can be resumed. In addition, in some aspects, the UE may not have PSFCH communications to send or receive. However, the additional LBT will result in undesirable overhead and reduced throughput. Therefore, the efficiency of the sidelink communication in the shared frequency band may be reduced.

[0078] The present disclosure provides systems, schemes, and mechanisms for maintaining COT on a PSFCH instance in a sidelink shared frequency communication. In some aspects, the mechanism for maintaining COT includes a first wireless communication device instructing a second wireless communication device to send a signal in at least one symbol between a sidelink communication channel and a sidelink feedback instance. In some aspects, the sidelink feedback instance may be a PSFCH instance. In some aspects, the signal may include a cyclic prefix (CP). In some aspects, the CP may be referred to as a CP extension (CPE). In some aspects, sending a signal may include sending a sidelink ACK / NACK in a PSFCH instance, wherein the CPE is at least partially extended within at least one gap symbol. The second wireless communication device may send a signal in at least one gap symbol so that the remaining gap between the PSSCH communication and the PSFCH communication is less than 25 μs. On the other hand, the second wireless communication device may send a signal so that the gap between the PSSCH and the PSFCH is less than about 16 μs. According to another aspect of the present disclosure, the first wireless communication device may instruct the second wireless communication device to send a fill signal or a pattern signal in at least one PSF viewing instance. For example, in some instances, the first wireless communication device may not expect to receive a PSFCH communication from the second wireless communication device. In addition, the first wireless communication device may not have sidelink feedback data for communicating in the PSFCH instance. Therefore, the first wireless communication device may instruct the second wireless communication device to send a fill signal, wherein the fill signal is based on the PSFCH waveform. In some aspects, sending the fill signal may include sending a CPE with a fill signal based on the PSFCH. In some aspects, the CPE may be sent in at least one gap symbol between the PSSCH instance and the PSFCH instance. According to another aspect of the present disclosure, a mechanism for maintaining COT may include rate matching the sidelink data to be spread over at least one gap symbol and / or PSFCH instance.

[0079] Figure 5 is a diagram illustrating a COT maintenance scheme 500 for sidelink communication in a shared frequency band. Various aspects of the present disclosure may be performed by a first wireless communication device and / or a second wireless communication device. For example, in one aspect, one or more actions of the scheme 500 may be performed by a first user equipment communicating with a second user equipment. Figure 5 5 shows a plurality of side link resources configured for side link communication between a first wireless communication device and a second wireless communication device, the side link resources being distributed over a time slot 510, the time slot 510 including a plurality of symbols 512. Figure 4, the time slot 510 may be part of a COT obtained by performing LBT in a shared frequency band. The communication within the time slot 510 includes side link control information (SCI) 520, PSSCH data 530, PSFCH data 540, automatic gain control symbol (AGC) 550, and gap symbol 560. For example, the first symbol of the time slot 510 includes a first AGC 552. The first AGC 552 may include or be based on a copy of the signal, waveform, and / or data in the symbol immediately following it. The SCI 520 communicated during the time slot 510 includes a first SCI 522 and a second SCI 524. In some aspects, the first SCI 522 includes SCI-1. On the other hand, the second SCI 524 includes SCI-2. In some aspects, the first SCI 522 is communicated using PSCCH resources, and the second SCI 524 is communicated using PSSCH resources. The time slot also includes PSSCH communication 532. The PSSCH communication 532 may include SL data, RRC information elements (IEs), medium access control (MAC) IEs, and / or control elements (CEs). The SL data may be communicated in one or more transport blocks (TBs).

[0080] In some aspects, the resources for each SL communication in the SL communication may be configured for the SL resource pool. In some aspects, the SL resource pool may indicate the time and / or frequency resources for each of a plurality of channels (such as PSCCH, PSSCH, and PSFCH). In some aspects, the allocation of frequency resources may include one or more sets of resource blocks (RBs), one or more interleavings of RBs, one or more subchannels, and / or one or more partial RBs. In some aspects, the frequency resources may be different for different channels. For example, the SL resource pool may indicate a first subset of frequency resources for SCI 520, a second subset of frequency resources for PSSCH communication 530, and a third subset of frequency resources for PSFCH communication 540. In some aspects, the SL resource pool may include or indicate a first interleaving of RBs for PSSCH communication 530 and a second interleaving of RBs for PSFCH communication 540. In addition, the UE may be configured with a mapping scheme or configuration for mapping PSSCH resources to PSFCH resources. For example, the PSFCH resources may be divided into subsets or portions, with each subset allocated for PSSCH communications 530 in a given PSSCH resource and / or time slot.

[0081] For PSFCH communications, the UE may be configured with a dynamic HARQ timeline or a fixed HARQ timeline. For a dynamic HARQ timeline, the SCI in each time slot may include a value of K1, which indicates which PSFCH instance carries SL feedback information for the associated PSSCH in a later time slot. For example, a K1 value of 5 may indicate that SL feedback information (e.g., ACK, NACK) for the associated PSSCH communication may be provided in a future PSFCH resource 5 time slot. For a fixed HARQ timeline, the UE may be configured with a MinTimeGapPSFCH value, which indicates the minimum number of time slots after the last time slot of a PSSCH communication before the UE sends a PSFCH.

[0082] The time slot 510 includes a PSFCH instance 542. For example, the UE may be configured with a periodic PSFCH resource that occurs once every n time slots. In some aspects, n may be 1, 2, 3, 4, 5, 6, 8, and / or any other suitable number of time slots. In some aspects, the value of n may be referred to as a PSFCH period, as explained above. There is at least one gap symbol 562 and an AGC symbol 554 between the PSSCH communication 532 and the PSFCH resource 542. In some aspects, the duration of the gap symbol 562 may be greater than a threshold configured for COT maintenance. For example, the duration of the symbol 562 may be greater than 25 μs and / or greater than 16 μs. In scheme 500, the first wireless communication device instructs the second wireless communication device to transmit a signal in at least a portion of the gap symbol 562 utilizing the PSFCH communication 542. Figure 5 In the example shown, the first wireless communication device instructs the second wireless communication device to add a CP extension (CPE) 572 to the AGC 554 within at least a portion of the gap symbol 562. The communication of the CPE 572 reduces the duration of the gap 564 between the PSSCH 532 and the PSFCH instance 542. In some aspects, the communication of the CPE 572 can reduce the duration of the gap 564 to below a configured COT maintenance threshold. For example, the second wireless communication device can communicate the CPE 572 so that the duration of the gap 564 is less than 25 μs and / or less than 16 μs. As a result, the first wireless communication device can continue to communicate using the COT in subsequent time slots.

[0083] In some instances, the PSFCH communication in the PSFCH instance 542 may include a SL ACK / NACK sent by the second wireless communication device to confirm the receipt or non-reception of one or more PSSCH communications sent by the first wireless communication device. For example, in some aspects, the PSFCH communication may indicate a SL ACK / NACK for one or more PSSCH instances before the PSFCH resource. In some aspects, the PSFCH communication in the PSFCH instance 542 may indicate an ACK / NACK for each PSSCH communication in the PSFCH period. In some aspects, the PSFCH communication in the PSFCH instance 542 may indicate an ACK / NACK for PSSCH communications within multiple PSFCH periods. On the other hand, the PSFCH communication in the PSFCH instance 542 may indicate an ACK / NACK or other SL feedback information associated with the SCI 520. For example, the first wireless communication device may instruct the second wireless communication device to send SL feedback information based on decoding at least one of the first SCI 522 or the second SCI 524. Therefore, if the second wireless communication device does not have PSFCH information to send in the PSFCH instance 542, the second wireless communication device can send SL feedback information in the PSFCH instance 542 based on decoding the SCI 522, 524.

[0084] In another aspect, sending a PSFCH communication in instance 542 may include sending a filler signal or padding signal in the PSFCH instance 542. For example, if the first wireless communication device does not expect to receive SL feedback information in the PSFCH instance 542, the first wireless communication device may instruct the second wireless communication device to send a filler signal in the instance 542. The filler signal may be based on the PSFCH waveform. Thus, the second wireless communication device may send a PSFCH-based filler signal together with the AGC 554 and the CPE 572, such that the filler signal, the AGC 554, and the CPE 572 at least partially close or fill the gap 564 in the communication between the PSFCH instance 542 and the PSSCH 532. Thus, the COT is maintained so that the first wireless communication device can resume communication in a second time slot after the PSFCH instance 542. In some aspects, the first wireless communication device that resumes communication in a subsequent time slot may include an additional CPE 574 in at least a portion of the second gap symbol 564 after the PSFCH instance 542. Therefore, the combination of the second wireless communication device turning off the first gap symbol 562 and the first wireless communication device turning off the second gap symbol 564 can maintain the COT for additional PSSCH communications after the PSFCH instance 542.

[0085] Figure 6 6 is a signaling diagram of a method 600 for wireless communication performed by a first UE (UE A) and a second UE (UE B). The UE may be UE 115 in network 100 and / or UE 215 in network 200. The method 600 may include Figure 5 . Method 600 may include UE A and UE B communicating via a sidelink interface in a shared frequency band. For example, method 600 may include communicating using a sidelink unlicensed (SL-U) protocol. In some aspects, UE A and UE B may communicate using a PC5 interface. As described above, in order to communicate in a shared or unlicensed frequency resource, one or both of UE A and UE B may perform a clear channel assessment (CCA) (such as listen before talk (LBT)) to obtain a set of time resources in a frequency band or sub-band. The time resource may be referred to as a channel occupancy time (COT).

[0086] At action 602, UE A performs LBT to initiate or obtain COT 610. In some aspects, the LBT may be a CAT4 LBT with a random backoff period. In other aspects, the LBT may be a CAT2 LBT. Performing LBT may include obtaining signal measurements within a configured time period. In some aspects, the time period may be variable. For example, the time period may include a random backoff period associated with a random backoff counter value. On the other hand, the time period may be fixed. Based on the LBT, UE A initiates COT 610. COT 610 may include a time period during which UE A may communicate with one or more UEs (including UE B) in the network. In some aspects, the time period may be configured as a value in an absolute time unit (such as ms or μs). On the other hand, the time period may be configured as a value of a frame, a subframe, and / or a time slot.

[0087] At action 604, UE A sends SL communication including PSCCH communication and PSSCH communication to UE B. In some aspects, the PSCCH communication may include SCI. The SCI may be SCI-1 and / or SCI-2. In some aspects, the SCI may include an indication to UE B to send a signal to UE A during at least one gap symbol before the PSFCH resource. In other words, the SCI may instruct UE B to send a signal in at least one gap symbol, wherein the at least one gap symbol is between the PSSCH communication and the PSFCH resource. The PSFCH resource may be a periodic and / or semi-persistent PSFCH resource scheduled for a period of time after the PSSCH communication. The PSFCH resource may be during the COT so that if the COT is maintained, additional PSCCH and / or PSSCH resources may be used after the PSFCH resource.

[0088] In some aspects, action 604 includes UE A instructing UE B to send CPE using PSFCH communication, wherein the CPE is sent during at least one gap symbol. The CPE may include an extension of an AGC symbol sent together with ACK / NACK information associated with PSSCH communication and / or one or more previous PSSCH communications. On the other hand, action 604 includes UE A instructing UE B to send a PSFCH-based fill signal with CPE to extend within at least one gap symbol. For example, UE A may instruct UE B to send a PSFCH-based fill signal based on UE A determining that ACK / NACK information from UE B is not expected in a PSFCH instance. In some aspects, action 604 includes UE A instructing UE B to send a PSFCH-based fill signal in each of one or more PSFCH instances before n+K1. For example, in addition to the indication of sending a PSFCH-based fill signal with CPE, the SCI sent at action 604 may also include an indication of the value of n. In other examples, UE A may instruct UE B to send a PSFCH-based fill signal only in the next PSFCH instance.

[0089] On the other hand, action 604 may include UE A or UE B selecting a PSFCH frequency resource or a subset of frequency resources to send a PSFCH-based filling signal. For example, UE A or UE B may select a set of frequency resources that are orthogonal to the resources used by other potential Tx-Rx pairs for a PSFCH-based filling signal. In one example, UE A or UE B may select a set of frequency resources for a PSFCH-based filling signal based on an identifier of the UE (UE A) that initiates the COT. For example, UE A or UE B may select the set of frequency resources based on its own L1 identifier. In this regard, UE A or UE B may select a PSFCH resource block (RB) group, RB set and / or RB interleaving based on the ID of UE A. According to another aspect, UE A or UE B may be configured with a reserved PSFCH resource for sending a PSFCH-based filling signal. For example, UE A and / or UE B may be configured with a reserved cyclic shift (CS), RB group and / or RB interleaving for sending a PSFCH-based filling signal. On the other hand, UE B may randomly select a PSFCH RB group and / or RB interlace. In some aspects, the reserved frequency resources for PSFCH transmission by UE B may be excluded from the PSFCH resource pool. In some aspects, other UEs in the network that send SL feedback information (e.g., ACK / NACK) in a PSFCH instance with a PSFCH-based fill signal may all select ACK to send in the PSFCH instance. In another example, other UEs that send SL feedback information in a PSFCH instance may all select NACK to send in the PSFCH instance.

[0090] In another aspect, action 604 includes UE A instructing UE B to send an ACK / NACK with CPE, wherein the ACK / NACK is associated with the PSCCH sent at action 604. For example, UE A may determine whether it expects PSFCH information from UE B, and based on the indication, send an SCI in the PSCCH, the SCI instructing UE B to send a PSFCH indicating an ACK / NACK for the SCI. The SCI may instruct UE B to send the CPE together with the PSFCH.

[0091] At act 606, UE B sends at least one of the following based on the indication of act 604: (1) PSFCH with CPE, or (2) a fill signal based on PSFCH with CPE, and UE A receives at least one of the following based on the indication of act 604: (1) PSFCH with CPE, or (2) a fill signal based on PSFCH with CPE. In some aspects, the CPE is sent within at least a portion of the gap symbol between the PSSCH and the PSFCH resource sent at act 604. For example, the CPE may be sent to cover a portion of the gap symbol between the final PSSCH symbol and the AGC symbol before the PSFCH symbol. For example, the PSFCH and the CPE / fill signal and the transmission of the CPE may be sent such that the gap between the PSCCH / PSSCH in act 604 and the communication of act 606 is less than 25 μs. In another example, the gap may be less than 16 μs. In some aspects, act 606 includes sending an ACK / NACK for the PSCCH sent at act 604. In another aspect, act 606 includes sending an ACK / NACK for one or more previous PSSCH communications.

[0092] At action 608, UE A sends a second SL communication including a second PSCCH and a second PSSCH, and UE B receives the second SL communication. Figure 6 As illustrated, actions 604, 606, and 608 and their associated communications are performed within COT 610. Thus, based on the indication sent at action 604 and the transmission by UE B at action 606, COT 610 is maintained such that a new LBT may not be performed. Thus, the remaining portion of COT 610 may be used after the PSFCH instance by at least partially closing the link switch gap associated with the PSFCH instance. In some aspects, action 608 may include UE A transmitting the CPE in a gap symbol before the first PSCCH / PSSCH symbol after the PSFCH instance.

[0093] Figure 7700 is a flow chart illustrating a scheme 700 for COT maintenance for sidelink communications in a shared frequency band according to various aspects of the present disclosure. As will be appreciated, scheme 700 may include aspects of schemes 500 and / or 600. For example, scheme 700 may be performed by a first wireless communication device communicating with a second wireless communication device using a sidelink communication protocol. In some aspects, scheme 700 may provide a decision architecture or protocol for selecting a COT maintenance mechanism. Various aspects of scheme 700 may be performed by a UE (such as one of UE 115, 215). Scheme 700 may relate to or be associated with UE configuration. UE configuration may include a set of rules or hard decoding protocols for maintaining COT through PSFCH resources.

[0094] At action 702, the UE determines whether the UE has SL feedback information to be sent in a PSFCH resource. In some aspects, the PSFCH resource may be in the middle of a SL TB burst. Therefore, there may be additional time resources after the PSFCH resource that the UE can use for additional SL communications. Determining whether the UE has SL feedback to send may include determining whether the UE has received a PSSCH in one or more time slots during a PSFCH period associated with the PSFCH resource. If the UE determines that there is a PSFCH to be sent, at action 704, the UE may send a PSFCH (e.g., ACK / NACK) in a PSFCH resource with a CPE at the beginning of the PSFCH. For example, the UE may send a PSFCH with a CPE in at least one gap symbol before the PSFCH resource such that the remaining gap is equal to or below a configured threshold.

[0095] At action 706, the UE determines whether the UE desires to receive SL feedback information to be received from one or more other UEs in the PSFCH resources.Determining whether the UE has SL feedback information to receive may include determining whether the UE has sent PSSCH communications to one or more other UEs during the PSFCH period.

[0096] If the UE determines that there is SL feedback information to be received during the PSFCH instance, then at action 708, the UE may instruct the second UE transmitting the PSFCH to transmit the PSFCH with CPE within at least one gap symbol before the PSFCH resource, as described above with respect to Figure 5 and Figure 6If the UE determines that there is no SL feedback information to be received in the PSFCH resource, the UE may perform at least one of actions 710 or 712. For example, in action 710, the UE instructs the second UE to send a PSFCH-based fill signal in the PSFCH resource with the CPE. As an alternative to action 710, the UE may rate match the PSSCH communication preceding the PSFCH resource so that the PSSCH communication is spread over the PSSCH resource and the intervening gap symbols. In the following Figure 8 , Fig.9A and Fig. 9B Various aspects of action 712 are illustrated in FIG.

[0097] On the other hand, at action 714, if the UE expects to receive SL feedback information in a PSFCH instance, the UE may alternatively determine to delay PSFCH resources and / or associated link switching until the end of the transmit burst. In some aspects, the UE may determine to delay the PSFCH instance or the communication of the PSFCH until the PSFCH instance approaches the end of the COT. For example, in a fixed HARQ timeline, the UE may delay the PSFCH instance by setting MinTimeGapPSFCH to have a larger value. In a dynamic HARQ timeline, the UE may set the K1 value so that the SL feedback information is communicated at the end of the data burst.

[0098] Figure 8 8 is a signaling diagram of a method 800 for wireless communication performed by a first UE (UE A) and a second UE (UE B). UE A and / or UE B may be UE 115 in network 100 and / or UE 215 in network 200. Method 800 may include Figures 5 to 7 In particular, Figure 8 Aspects of action 712 of scheme 700 may be illustrated. Method 800 may include UE A and UE B communicating via a sidelink interface in a shared frequency band. For example, method 800 may include communicating using an SL-U protocol. In some aspects, UE A and UE B may communicate using a PC5 interface. As described above, in order to communicate in a shared or unlicensed frequency resource, one or both of UE A and UE B may perform a clear channel assessment (CCA) (such as listen before talk (LBT)) to obtain a set of time resources in a frequency band or sub-band. The time resource may be referred to as a channel occupancy time (COT).

[0099] At action 802, UE A performs LBT to initiate or obtain COT 610. In some aspects, the LBT may be a CAT4 LBT with a random backoff period. In other aspects, the LBT may be a CAT2 LBT. Performing LBT may include obtaining signal measurements within a configured time period. In some aspects, the time period may be variable. For example, the time period may include a random backoff period associated with a random backoff counter value. On the other hand, the time period may be fixed. Based on the LBT, UE A initiates COT 810. COT 810 may include a time period during which UE A may communicate with one or more UEs in the network, including UE B. In some aspects, the time period may be configured as a value in an absolute time unit (such as ms or μs). On the other hand, the time period may be configured as a value of a frame, a subframe, and / or a time slot.

[0100] At action 804, UE A sends SL communications including PSCCH communications and PSSCH communications to UE B. In method 800, UE A rate matches the PSSCH communications to extend the PSFCH resources scheduled during COT 810. In this regard, Fig.9A and Fig. 9B Various aspects of PSSCH rate matching for COT maintenance are illustrated. Fig.9A , showing a SL time slot, which in some respects may be similar to Figure 5 The time slot 510 shown in FIG. Fig.9AIn the embodiment of the present invention, the communication within the time slot includes SCI 920, PSSCH data 930, PSFCH data 940, AGC symbol 950 and gap symbol 960. For example, the first symbol of the time slot includes the first AGC 952. The first AGC 952 may include or be based on a copy of the signal, waveform and / or data in the symbol immediately following it. The SCI 920 communicated during the time slot includes the first SCI 922 and the second SCI 924. In some aspects, the first SCI 922 includes SCI-1. On the other hand, the second SCI 924 includes SCI-2. In some aspects, the first SCI 922 is communicated using PSCCH resources, and the second SCI 924 is communicated using PSSCH resources. The time slot also includes PSSCH communication 932. PSSCH communication 932 may include SL data, RRC information elements (IE), medium access control (MAC) IE and / or control elements (CE). SL data may be communicated in one or more transport blocks (TBs). The time slot includes a PSFCH instance 942, which may be referred to as a PSFCH symbol. The PSFCH instance 942 is preceded by an AGC symbol 954 and a gap symbol 962. The gap symbol 962 may be greater than a configured COT maintenance threshold. For example, the gap symbol 962 may have a duration longer than 16 μs and / or longer than 25 μs.

[0101] refer to Fig. 9B , the UE may rate match the PSSCH communication 932 to include an extended PSSCH portion 945. The extended PSSCH portion 945 includes rate matched PSSCH data in symbols previously configured or allocated as PSFCH symbols or instances 942, AGC symbols 954, and gap symbols 962, 964. Referring again to Figure 7 In some aspects, the UE may select action 712 instead of action 710 based on the configuration of the COT or the UE configuration and / or capabilities regarding COT sharing. For example, in some aspects, the second UE may not be configured to share the COT for sending SL feedback information. Therefore, the UE may determine to rate match the PSSCH based on the UE configuration for COT sharing instead of instructing the second UE to send a PSFCH with a CPE and / or a PSFCH-based fill signal with a CPE.

[0102] Return to Figure 8, at act 806, UE A sends a second PSSCH and PSCCH communication in COT 810, and UE B receives the second PSSCH and PSCCH communication in COT 810. Thus, UE A can continue to communicate in COT 810 without performing additional LBT. In some aspects, the PSCCH sent at act 804 may include an SCI indicating the rate matching behavior of UE A to UE B so that UE B can successfully receive and decode the PSSCH communication at act 806.

[0103] Fig.10 1 is a block diagram of an exemplary UE 1000 according to some aspects of the present disclosure. UE 1000 may be the Figure 1 UE 115 discussed in or above in Figure 2 215 discussed in . As shown, UE 1000 may include a processor 1002, a memory 1004, a sidelink communication 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 communicate with each other directly or indirectly, for example, via one or more buses.

[0104] 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 conjunction with a DSP core, or any other such configuration.

[0105] The memory 1004 may include cache memory (e.g., cache memory of the 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 one aspect, the memory 1004 includes a non-transitory computer-readable medium. The memory 1004 may store or have recorded thereon instructions 1006. The instructions 1006 may include instructions that, when executed by the processor 1002, cause the processor 1002 to perform various aspects of the present disclosure described herein (e.g., Figures 5 to 9B1006. The instructions 1006 may also be referred to as program code. The program code may be used to cause the wireless communication device to perform the operations, for example, by causing one or more processors (such as processor 1002) to control or command the wireless communication device to do so. 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.

[0106] The sidelink communication module 1008 may be implemented via hardware, software, or a combination thereof. For example, the sidelink communication module 1008 may be implemented as a processor, circuit, and / or instructions 1006 stored in the memory 1004 and executed by the processor 1002. In some examples, the sidelink communication module 1008 may be integrated within the modem subsystem 1012. For example, the sidelink communication module 1008 may be implemented by a combination of software components (e.g., executed by a DSP or general purpose processor) and hardware components (e.g., logic gates and circuits) within the modem subsystem 1012.

[0107] The side link communication module 1008 may be used in various aspects of the present disclosure, such as Figures 5 to 9BAspects of. For example, the sidelink communication module 1008 is configured to send a first SL communication including sidelink (SL) communication information (SCI) in a first portion of a channel occupancy time (COT) based on listen-before-talk (LBT). The SCI may indicate that the second wireless communication device sends a signal in at least one gap symbol before a physical sidelink feedback channel (PSFCH). In some aspects, the sidelink communication module 1008 is configured to perform LBT in a shared radio frequency band (e.g., band 301) within a LBT gap duration (e.g., LBT gap duration 310). For example, the sidelink communication module 1008 may be configured to perform CAT2 LBT, CAT4 LBT, and / or any suitable type of LBT to initiate or acquire a COT. In some aspects, the sidelink communication module 1008 is configured to send a first SL communication that may include sending SCI in a PSCCH and / or in a PSSCH. In addition, the sidelink communication module 1008 may be configured to send SL data in a PSSCH. In some aspects, communication may occur in one or more time slots within a COT. The time slot may include one or more symbols allocated for the PSFCH resource. For example, after the PSSCH resource, the time slot may include or be configured with at least one first slot symbol, at least one AGC symbol, at least one PSFCH symbol, and at least another slot symbol. In some aspects, the SCI instructs the second wireless communication device to send ACK / NACK in the PSFCH resource or instance and send a cyclic prefix extension (CPE) in the first slot symbol before the PSFCH resource. In other aspects, the SCI instructs the second wireless communication device to send a PSFCH-based fill signal in the PSFCH resource with the CPE in the first slot symbol. In some aspects, the SCI instructs the second wireless communication device to send an ACK / NACK for the SCI in the first SL communication.

[0108] In another aspect, the sidelink communication module 1008 may be configured to receive a signal from a second wireless communication device in a shared frequency band during at least one gap symbol. As described above, the sidelink communication module 1008 may receive a PSFCH with a CPE. In some aspects, the PSFCH may indicate an ACK / NACK for one or more PSSCH communications in one or more PSFCH periods associated with a PSFCH resource. In some aspects, the PSFCH may indicate an ACK / NACK for a first SL communication. For example, the PSFCH may indicate an ACK / NACK for an SCI included in the first SL communication.

[0109] On the other hand, the sidelink communication module 1008 may be configured to send a second SL communication in a second part of the COT based on the LBT. In some aspects, the second part of the COT is after the PSFCH resource. For example, the first part of the COT may be in a first time slot within the COT, and the second part of the COT may be in a second time slot within the COT. In some aspects, the sidelink communication module 1008 may be configured to send PSCCH and / or PSSCH communications. In this regard, based on receiving a signal during at least one gap symbol, the sidelink communication module 1008 may be configured to maintain the COT so that the first wireless communication device can resume communication within the COT after the PSFCH resource without performing additional LBT.

[0110] According to another aspect of the present disclosure, the sidelink communication module 1008 may be configured to perform listen before talk (LBT) in a shared radio frequency band to initiate a channel occupation time (COT). For example, the sidelink communication module 1008 may be configured to perform CAT2 LBT, CAT4 LBT, and / or any suitable type of LBT to initiate or acquire a COT. In addition, the sidelink communication module 1008 may be configured to send a first SL communication in the COT based on the LBT, wherein the first SL communication is rate matched to occupy at least a portion of the SL feedback resources during the COT. For example, the sidelink communication module 1008 may be configured to send a first SL communication including SCI and SL data. The COT may include SL data resources and SL feedback resources. In some aspects, the SL feedback resources may include one or more PSFCH instances or symbols. In some aspects, sending the first SL communication may include sending the SCI in the PSCCH and / or in the PSSCH. On the other hand, the first SL communication may include a PSSCH communication. The sidelink communication module 1008 may be configured to rate match at least a portion of the PSSCH communication to occupy at least a portion of the SL data resources and the SL feedback resources. For example, the sidelink communication module 1008 may be configured to rate match the PSSCH communication to extend within at least one of the slot symbols, AGC symbols, and / or PSFCH symbols of the time slot. Based on sending the rate-matched first SL communication, the sidelink communication module 1008 may be configured to continue to perform SL communication in the COT in additional time resources. For example, the sidelink communication module 1008 may be configured to convey additional PSCCH and / or PSSCH communications in one or more time slots in the COT following the SL feedback resources.

[0111] 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 BS 105. The modem subsystem 1012 may be configured to modulate and / or encode data from the memory 1004 and / or the sidelink communication module 1008 according to a modulation and coding scheme (MCS) (e.g., a low-density parity check (LDPC) coding scheme, a turbo coding scheme, a convolutional coding scheme, a polarization coding 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 (e.g., SCI, sidelink data, LBT starting point reservation) from the modem subsystem 1012 (for outbound transmission) or from another source (such as UE 115 or BS 105). The RF unit 1014 may be further configured to perform analog beamforming in conjunction with digital beamforming. Although shown as integrated together in the transceiver 1010, the modem subsystem 1012 and the RF unit 1014 may be separate devices that are coupled together at the UE 115 to enable the UE 115 to communicate with other devices.

[0112] The RF unit 1014 may provide modulated and / or processed data, such as data packets (or more generally, data messages that may contain 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 messages for processing and / or demodulation at the transceiver 1010. The transceiver 1010 may provide the demodulated and decoded data (e.g., side link configuration, resource pool configuration) to the side link communication module 1008 for processing. The antenna 1016 may include multiple antennas of similar design or different design to maintain multiple transmission links. The RF unit 1014 may configure the antenna 1016.

[0113] In some aspects, the transceiver 1010 is configured to perform LBT in a shared RF band based on a first starting point among multiple starting points within the LBT gap duration, and to send a first side link communication to a second UE (e.g., UE 115, 215 and / or 1000) in the shared RF band based on the LBT, for example by coordinating with the side link communication module 1008, the first side link communication comprising a first SCI and first side link data.

[0114] In one aspect, the UE 1000 may include multiple transceivers 1010 that implement different RATs (e.g., NR and LTE). In one aspect, the UE 1000 may include a single transceiver 1010 that implements multiple RATs (e.g., NR and LTE). In one aspect, the transceiver 1010 may include various components, where different combinations of components may implement different RATs.

[0115] Fig.11 is a block diagram of an exemplary BS 1100 according to some aspects of the present disclosure. BS 1100 may be as described above in Figure 1 BS 105 in network 100 discussed in or as described above in Figure 2 1. As shown, BS 1100 may include a processor 1102, a memory 1104, a side link configuration module 1108, a transceiver 1110 (including a modem subsystem 1112 and an RF unit 1114), and one or more antennas 1116. These elements may communicate with each other directly or indirectly, for example, via one or more buses.

[0116] 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 conjunction with a DSP core, or any other such configuration.

[0117] The memory 1104 may include cache memory (e.g., cache memory of the 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 non-volatile memory, or a combination of different types of memory. In some aspects, the memory 1104 may include a non-transitory computer-readable medium. The memory 1104 may store instructions 1106. The instructions 1106 may include instructions that, when executed by the processor 1102, cause the processor 1102 to perform the operations described herein (e.g., Figures 5 to 9B Instructions 1106 may also be referred to as code, which may be broadly interpreted to include any type of computer-readable statements, such as those described above with respect to Fig.10 discussed.

[0118] The sidelink configuration module 1108 may be implemented via hardware, software, or a combination thereof. For example, the sidelink configuration module 1108 may be implemented as a processor, circuit, and / or instructions 1106 stored in the memory 1104 and executed by the processor 1102. In some examples, the sidelink configuration module 1108 may be integrated within the modem subsystem 1112. For example, the sidelink configuration module 1108 may be implemented by a combination of software components (e.g., executed by a DSP or general purpose processor) and hardware components (e.g., logic gates and circuits) within the modem subsystem 1112.

[0119] The side link configuration module 1108 may be used in various aspects of the present disclosure, such as Figures 5 to 9B For example, the sidelink configuration module 1108 may be configured to send a sidelink configuration indicating a sidelink resource pool and / or a PSFCH configuration to a UE (e.g., UE 115, 215, and / or 1000). The sidelink configuration may indicate time-frequency resources (e.g., frequency band 301, frequency subband 302, sidelink communication frame structure 304, LBT starting points allowed within the LBT gap duration) and / or a sidelink service priority category for the sidelink resource pool. The present invention describes in more detail the mechanisms for configuring a sidelink UE for channel access in a shared radio frequency band and / or an unlicensed band.

[0120] 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 UE 115 and / or 1000 and / or another core network element). 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 polarization 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.) modulated / encoded data (e.g., PDCCH, PDSCH, SSB, sidelink configuration, sidelink resource pool configuration, etc.) from the modem subsystem 1112 (for outbound transmission) or from another source (such as UE 115 and / or UE 1000). The RF unit 1114 may be further configured to perform analog beamforming in conjunction with digital beamforming. Although shown as integrated together in transceiver 1110, modem subsystem 1112 and / or RF unit 1114 may be separate devices that are coupled together at BS 105 to enable BS 105 to communicate with other devices.

[0121] The RF unit 1114 may provide modulated and / or processed data, such as data packets (or more generally, data messages 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 some aspects of the present disclosure, this may include the transmission of information to complete the attachment to the network and the communication with the pre-occupied UE 115 or 1000. 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 transceiver 1110 may provide the demodulated and decoded data to the side link configuration module 1108 for processing. The antenna 1116 may include multiple antennas of similar design or different design to maintain multiple transmission links.

[0122] In one aspect, the BS 1100 may include multiple transceivers 1110 that implement different RATs (e.g., NR and LTE). In one aspect, the BS 1100 may include a single transceiver 1110 that implements multiple RATs (e.g., NR and LTE). In one aspect, the transceiver 1110 may include various components, where different combinations of components may implement different RATs.

[0123] Fig.12 1000 , a sidelink communication method 1200 according to some aspects of the present disclosure. Aspects of the method 1200 may be performed by a computing device (e.g., a processor, a processing circuit, and / or another suitable component) of a wireless communication device or another suitable means for performing steps. For example, a wireless communication device (such as UE 115, 215, and / or 1000) may utilize one or more components (such as processor 1002, memory 1004, sidelink communication module 1008, transceiver 1010, modem 1012, and one or more antennas 1016) to perform the steps of the method 1200. The method 1200 may be implemented in the same manner as described above with respect to Figure 5 , Figure 6 , Figure 7 and Figure 8 The method 1200 includes several steps listed, but aspects of the method 1200 may include additional steps before, after, and between the steps listed. In some aspects, one or more of the steps listed may be omitted or performed in a different order.

[0124] At block 1210, the first wireless communication device transmits a first SL communication including sidelink (SL) communication information (SCI) in a first portion of a channel occupancy time (COT) based on listen-before-talk (LBT). The SCI may indicate that the second wireless communication device transmits a signal in at least one gap symbol before a physical sidelink feedback channel (PSFCH). In some aspects, the method 1200 includes performing LBT in a shared radio frequency band (e.g., band 301) within a LBT gap duration (e.g., LBT gap duration 310). For example, the first wireless communication device may perform CAT2 LBT, CAT4 LBT, and / or any suitable type of LBT to initiate or acquire a COT. In some instances, the first wireless communication device may utilize one or more components (such as a processor 1002, a sidelink communication module 1008, a transceiver 1010, a modem 1012, and one or more antennas 1016) to perform LBT by measuring signal energy in a shared RF band starting at a first starting point and within the duration of a CCA slot (e.g., ending at a next starting point), comparing the channel signal measurement to a threshold, determining that LBT is passed (e.g., the channel is available) when the channel signal measurement is below the threshold, and determining that LBT fails (e.g., the channel is busy) when the channel signal measurement is above the threshold. In some aspects, sending a first SL communication may include sending SCI in a PSCCH and / or in a PSSCH. In addition, sending a first SL communication may include sending SL data in a PSSCH. In some aspects, communication may occur in one or more time slots within a COT. A time slot may include one or more symbols allocated for a PSFCH resource. For example, after a PSSCH resource, a time slot may include or be configured with at least one first gap symbol, at least one AGC symbol, at least one PSFCH symbol, and at least another gap symbol. In some aspects, the SCI instructs the second wireless communication device to send an ACK / NACK in a PSFCH resource or instance and to send a cyclic prefix extension (CPE) in a first slot symbol before the PSFCH resource. In other aspects, the SCI instructs the second wireless communication device to send a PSFCH-based fill signal in a PSFCH resource with a CPE in a first slot symbol. In some aspects, the SCI instructs the second wireless communication device to send an ACK / NACK for the SCI in a first SL communication. The first wireless communication device may perform the actions of block 1210 using one or more components, such as a processor 1002, a sidelink communication module 1008, a transceiver 1010, a modem 1012, and one or more antennas 1016.

[0125] At block 1220, the first wireless communication device receives a signal from the second wireless communication device in a shared frequency band during at least one gap symbol. As described above, receiving the signal may include receiving a PSFCH with a CPE. In some aspects, the PSFCH may indicate an ACK / NACK for one or more PSSCH communications in one or more PSFCH periods associated with the PSFCH resource. In some aspects, the PSFCH may indicate an ACK / NACK for a first SL communication. For example, the PSFCH may indicate an ACK / NACK for an SCI included in the first SL communication. The first wireless communication device may perform the actions of block 1220 using one or more components, such as a processor 1002, a sidelink communication module 1008, a transceiver 1010, a modem 1012, and one or more antennas 1016.

[0126] At box 1230, the first wireless communication device sends a second SL communication in a second part of the COT based on the LBT. In some aspects, the second part of the COT is after the PSFCH resource. For example, the first part of the COT can be in a first time slot within the COT, and the second part of the COT can be in a second time slot within the COT. In some aspects, sending the second SL communication may include sending PSCCH and / or PSSCH communications. In this regard, based on receiving a signal during at least one gap symbol, at box 1220, the first wireless communication device may maintain the COT so that the first wireless communication device can resume communication within the COT after the PSFCH resource without performing additional LBT. The first wireless communication device can utilize one or more components (such as a processor 1002, a sidelink communication module 1008, a transceiver 1010, a modem 1012, and one or more antennas 1016) to perform the actions of box 1230.

[0127] Fig.13 1000 , sidelink communication module 1008 , transceiver 1010 , modem 1012 , and one or more antennas 1016 . Figures 8 to 9BAs illustrated, method 1300 includes several of the enumerated steps, but aspects of method 1300 may include additional steps before, after, and between the enumerated steps. In some aspects, one or more of the enumerated steps may be omitted or performed in a different order.

[0128] At block 1310, the first wireless communication device performs listen before talk (LBT) in a shared radio frequency band to initiate a channel occupation time (COT). For example, the first wireless communication device may perform CAT2 LBT, CAT4 LBT, and / or any suitable type of LBT to initiate or acquire a COT. In some instances, the first wireless communication device may perform LBT using one or more components, such as the processor 1002, the sidelink communication module 1008, the transceiver 1010, the modem 1012, and the one or more antennas 1016, by measuring signal energy in a shared radio frequency band starting at a first starting point and for a duration of a CCA slot (e.g., ending at a next starting point), comparing the channel signal measurement to a threshold, determining that the LBT is passed (e.g., the channel is available) when the channel signal measurement is below the threshold, and determining that the LBT fails (e.g., the channel is busy) when the channel signal measurement is above the threshold. The first wireless communication device may utilize one or more components, such as a processor 1002 , a sidelink communication module 1008 , a transceiver 1010 , a modem 1012 , and one or more antennas 1016 , to perform the actions of block 1310 .

[0129] At box 1320, the first wireless communication device sends a first SL communication in the COT based on the LBT, wherein the first SL communication is rate matched to occupy at least a portion of the SL feedback resources during the COT. For example, the first wireless communication device may send a first SL communication including SCI and SL data. The COT may include SL data resources and SL feedback resources. In some aspects, the SL feedback resources may include one or more PSFCH instances or symbols. In some aspects, sending the first SL communication may include sending SCI in the PSCCH and / or in the PSSCH. On the other hand, the first SL communication may include PSSCH communication. The first wireless communication device may rate match at least a portion of the PSSCH communication to occupy at least a portion of the SL data resources and the SL feedback resources. For example, the first wireless communication device may rate match the PSSCH communication to extend within at least one of the gap symbols, AGC symbols and / or PSFCH symbols of the time slot. Based on sending the rate-matched first SL communication, the first wireless communication device may continue to perform SL communication in the COT in additional time resources. For example, the first wireless communication device may communicate additional PSCCH and / or PSSCH communications in one or more time slots in the COT following the SL feedback resource. The first wireless communication device may utilize one or more components (such as the processor 1002, the sidelink communication module 1008, the transceiver 1010, the modem 1012, and the one or more antennas 1016) to perform the actions of block 1320.

[0130] Exemplary Aspects of the Disclosure

[0131] Aspect 1. A method of wireless communication performed by a first wireless communication device, the method comprising: sending a first SL communication including sidelink (SL) communication information (SCI) in a first part of a channel occupancy time (COT) based on listen-before-talk (LBT), the SCI indicating a second wireless communication device to send a signal in at least one gap symbol before a physical sidelink feedback channel (PSFCH) resource; receiving the signal from the second wireless communication device during the at least one gap symbol; and sending a second SL communication in a second part of the COT based on the LBT, wherein the second part of the COT is after the PSFCH resource.

[0132] Aspect 2. A method according to Aspect 1, wherein receiving the signal includes receiving a physical sidelink feedback channel (PSFCH) signal and the signal, wherein the signal includes a first cyclic prefix (CP) preceding the PSFCH signal within the at least one gap symbol.

[0133] Aspect 3. The method according to aspect 2, wherein the SCI instructs the second wireless communication device to send the signal such that a duration between an end of the first portion of the COT and a start of the signal is less than or equal to 25 μs.

[0134] Aspect 4. A method according to any one of Aspects 2 to 3, wherein sending the second SL communication includes: sending a physical side link shared channel (PSSCH) signal in the second part of the COT; and sending a second CP in a gap period between the PSFCH signal and the second part of the COT.

[0135] Aspect 5. The method according to aspect 4, wherein the PSSCH signal includes an acknowledgement / negative acknowledgement (ACK / NACK) for decoding the SCI.

[0136] Aspect 6. A method according to any one of Aspects 2 to 5, wherein receiving the signal includes: receiving a PSFCH-based filling signal in the PSFCH resource; and receiving a first cyclic prefix (CP) before the PSFCH-based filling signal in the at least one gap symbol.

[0137] Aspect 7. A method according to Aspect 6, wherein the SCI indicates one or more PSFCH resources and a time slot index, the one or more PSFCH resources include the PSFCH resource, and wherein the SCI indicates the second wireless communication device to send the PSFCH-based fill signal in each PSFCH resource of one or more PSFCH opportunities before the time slot associated with the time slot index.

[0138] Aspect 8. A method according to any one of aspects 6 to 7, wherein the PSFCH resource is orthogonal to at least a second PSFCH resource used for communication of the PSFCH resource by a third wireless communication device.

[0139] Aspect 9. The method according to aspect 8, wherein the PSFCH resource is selected based on an identifier of the first wireless communication device.

[0140] Aspect 10. A method according to any one of aspects 8 to 9, wherein the PSFCH resources include reserved PSFCH resources.

[0141] Aspect 11. A method of wireless communication performed by a first wireless communication device, the method comprising: performing listen before talk (LBT) to initiate a channel occupation time (COT); and sending a first side link (SL) communication in the COT based on the LBT, the first SL communication comprising SL communication information (SCI) and SL data, the COT comprising SL data resources and SL feedback resources, wherein the SL data is rate matched to occupy at least a portion of the SL feedback resources and the SL data resources.

[0142] Aspect 12. A method according to Aspect 11, wherein: the SL feedback resources include at least one gap symbol, at least one automatic gain control (AGC) symbol and at least one physical sidelink feedback channel (PSFCH) symbol; and the SL data is rate matched to occupy the at least one gap symbol, the at least one AGC symbol and the at least one PSFCH symbol.

[0143] Aspect 13. The method according to any one of aspects 11 to 12, wherein the SCI indicates a rate matching behavior for the COT to the second wireless communication device.

[0144] Aspect 14. A first wireless communication device, comprising: a memory; a transceiver; and a processor in communication with the memory and the transceiver, wherein the first wireless communication device is configured to perform the steps according to any one of aspects 1 to 10.

[0145] Aspect 15. A first wireless communication device, comprising: a memory; a transceiver; and a processor in communication with the memory and the transceiver, wherein the first wireless communication device is configured to perform the steps according to any one of aspects 11 to 13.

[0146] Aspect 16. A non-transitory computer readable medium having program code recorded thereon, the program code comprising instructions executable by a processor of a first wireless communication device to cause the first wireless communication device to perform the steps according to any one of aspects 1 to 10.

[0147] Aspect 17. A non-transitory computer readable medium having program code recorded thereon, the program code comprising instructions executable by a processor of a first wireless communication device to cause the first wireless communication device to perform the steps according to any one of aspects 11 to 13.

[0148] Aspect 18. A first wireless communication device, comprising: means for performing the steps according to any one of aspects 1 to 10.

[0149] Aspect 19. A first wireless communication device, comprising: means for performing the steps according to any one of aspects 11 to 13.

[0150] 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.

[0151] 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, a combination of one or more microprocessors and a DSP core, or any other such configuration).

[0152] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. When implemented in software executed by a processor, the functions may be stored on a computer-readable medium or sent via a computer-readable medium as one or more instructions or codes. 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, hardware, firmware, hard wiring, or any combination thereof executed by a processor. 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), the "or" used in the enumeration of items (e.g., followed by an enumeration of items such as "at least one of" or "one or more of") indicates an inclusive enumeration, such that, for example, the enumeration 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).

[0153] As those skilled in the art will understand by now 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 specific aspects illustrated and described herein (as they are only some examples of the present disclosure), but should be fully equivalent to the attached claims and their functional equivalents.

Claims

1. A method of wireless communication performed by a first wireless communication device, the method comprising: transmitting a first SL communication including sidelink (SL) communication information (SCI) in a first portion of a channel occupancy time (COT) based on listen-before-talk (LBT), the SCI instructing the second wireless communication device to transmit a signal in at least one gap symbol before a physical sidelink feedback channel (PSFCH) resource; receiving the signal from the second wireless communication device during the at least one gap symbol; as well as A second SL communication is sent in a second part of the COT based on the LBT, wherein the second part of the COT is after the PSFCH resource.

2. The method of claim 1 , wherein receiving the signal comprises receiving a physical sidelink feedback channel (PSFCH) signal and the signal, wherein the signal comprises a first cyclic prefix (CP) preceding the PSFCH signal within the at least one slot symbol. 3 . The method of claim 2 , wherein the SCI instructs the second wireless communication device to transmit the signal such that a duration between an end of the first portion of the COT and a start of the signal is less than or equal to 25 μs.

4. The method of claim 2, wherein sending the second SL communication comprises: transmitting a physical sidelink shared channel (PSSCH) signal in the second portion of the COT; as well as A second CP is transmitted in a gap period between the PSFCH signal and the second part of the COT.

5. The method of claim 4, wherein the PSSCH signal includes an acknowledgement / negative acknowledgement (ACK / NACK) for decoding the SCI.

6. The method of claim 1 , wherein receiving the signal comprises: Receiving a PSFCH-based fill signal in the PSFCH resource; and receiving a first cyclic prefix (CP) preceding the PSFCH-based filling signal in the at least one gap symbol.

7. A method according to claim 6, wherein the SCI indicates one or more PSFCH resources and a time slot index, the one or more PSFCH resources include the PSFCH resource, and wherein the SCI instructs the second wireless communication device to send the PSFCH-based fill signal in each PSFCH resource at one or more PSFCH opportunities before the time slot associated with the time slot index.

8. The method of claim 6, wherein the PSFCH resource is orthogonal to at least a second PSFCH resource used for communication of the PSFCH resource by a third wireless communication device.

9. The method of claim 8, wherein the PSFCH resource is selected based on an identifier of the first wireless communication device.

10. The method of claim 8, wherein the PSFCH resources comprise reserved PSFCH resources.

11. A method of wireless communication performed by a first wireless communication device, the method comprising: Performing Listen Before Talk (LBT) to initiate Channel Occupancy Time (COT); as well as A first side link (SL) communication is sent in the COT based on the LBT, wherein the first SL communication includes SL communication information (SCI) and SL data, and the COT includes SL data resources and SL feedback resources, wherein the SL data is rate matched to occupy at least a portion of the SL feedback resources and the SL data resources.

12. The method according to claim 11, wherein: The SL feedback resource includes at least one slot symbol, at least one automatic gain control (AGC) symbol, and at least one physical sidelink feedback channel (PSFCH) symbol; and The SL data is rate matched to occupy the at least one slot symbol, the at least one AGC symbol, and the at least one PSFCH symbol.

13. The method of claim 11, wherein the SCI indicates a rate matching behavior for the COT to a second wireless communication device.

14. A first wireless communication device, the first wireless communication device comprising: Memory; Transceiver; and a processor in communication with the memory and the transceiver, wherein the first wireless communication device is configured to: transmitting a first SL communication including sidelink (SL) communication information (SCI) in a first portion of a channel occupancy time (COT) based on listen-before-talk (LBT), the SCI instructing the second wireless communication device to transmit a signal in at least one gap symbol before a physical sidelink feedback channel (PSFCH) resource; receiving the signal from the second wireless communication device during the at least one gap symbol; as well as A second SL communication is sent in a second part of the COT based on the LBT, wherein the second part of the COT is after the PSFCH resource.

15. A first wireless communication device according to claim 14, wherein the first wireless communication device is configured to receive the signal including the first wireless communication device being configured to: receive a physical sidelink feedback channel (PSFCH) signal and the signal, wherein the signal includes a first cyclic prefix (CP) preceding the PSFCH signal within the at least one gap symbol.

16. The first wireless communication device of claim 15, wherein the SCI instructs the second wireless communication device to transmit the signal such that a duration between an end of the first portion of the COT and a start of the signal is less than or equal to 25 μs.

17. The first wireless communication device of claim 15, wherein the first wireless communication device being configured to send the second SL communication comprises the first wireless communication device being configured to: transmitting a physical sidelink shared channel (PSSCH) signal in the second portion of the COT; and A second CP is transmitted in a gap period between the PSFCH signal and the second part of the COT.

18. The first wireless communication device of claim 17, wherein the PSSCH signal includes an acknowledgement / negative acknowledgement (ACK / NACK) for decoding the SCI.

19. A first wireless communication device according to claim 14, wherein the first wireless communication device is configured to receive the signal including the first wireless communication device being configured to: receive a PSFCH-based filling signal in the PSFCH resource; and receive a first cyclic prefix (CP) preceding the PSFCH-based filling signal in the at least one gap symbol.

20. A first wireless communication device according to claim 19, wherein the SCI indicates one or more PSFCH resources and a time slot index, the one or more PSFCH resources include the PSFCH resource, and wherein the SCI instructs the second wireless communication device to send the PSFCH-based filling signal in each PSFCH resource of one or more PSFCH opportunities before the time slot associated with the time slot index.

21. The first wireless communication device of claim 19, wherein the PSFCH resource is orthogonal to at least a second PSFCH resource used for communication of the PSFCH resource by a third wireless communication device.

22. The first wireless communication device of claim 21, wherein the PSFCH resource is selected based on an identifier of the first wireless communication device.

23. The first wireless communication device of claim 21, wherein the PSFCH resources comprise reserved PSFCH resources.

24. A first wireless communication device, the first wireless communication device comprising: Memory; Transceiver; and a processor in communication with the memory and the transceiver, wherein the first wireless communication device is configured to: Performing Listen Before Talk (LBT) to initiate Channel Occupancy Time (COT); and A first side link (SL) communication is sent in the COT based on the LBT, wherein the first SL communication includes SL communication information (SCI) and SL data, and the COT includes SL data resources and SL feedback resources, wherein the SL data is rate matched to occupy at least a portion of the SL feedback resources and the SL data resources.

25. The first wireless communication device of claim 24, wherein: The SL feedback resource includes at least one slot symbol, at least one automatic gain control (AGC) symbol, and at least one physical sidelink feedback channel (PSFCH) symbol; and The SL data is rate matched to occupy the at least one slot symbol, the at least one AGC symbol, and the at least one PSFCH symbol.

26. The first wireless communication device of claim 24, wherein the SCI indicates a rate matching behavior for the COT to a second wireless communication device.

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