Autonomous sidelink in license-exempt bands

Abstract

Wireless communication systems and methods are provided relating to autonomous sidelink communication in a radio frequency band shared by multiple network operators (e.g., in shared spectrum or unlicensed spectrum). A first user equipment (UE) performs LBT in the shared radio frequency band based on a first start point among a plurality of start points during the duration of a talk-before-listen (LBT) gap. The first UE transmits first sidelink communication, including first sidelink control information (SCI) and first sidelink data, to a second UE in the shared radio frequency band based on the LBT.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of U.S. Patent Application No. 17 / 090,393 filed on November 5, 2020 and U.S. Provisional Patent Application No. 62 / 950,436 filed on December 19, 2019, the entire contents of which are incorporated herein by reference as if fully set forth below and for all applicable purposes. Technical Field

[0003] The present application relates to wireless communication systems, and more particularly, to autonomous sidelink communications in a radio frequency band shared by multiple network operating entities (eg, in a shared spectrum or an unlicensed spectrum). Background Art

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

[0005] In order to meet the growing demand for 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 intended to provide lower latency, higher bandwidth or higher throughput, and higher reliability than LTE. NR is designed to operate on a wide spectrum band array, for example, from low-frequency bands below about 1 gigahertz (GHz) and medium-frequency bands from about 1 GHz to about 6 GHz to high-frequency bands such as millimeter wave (mmWave) bands. NR can also operate across different spectrum types, from licensed spectrum to unlicensed and shared spectrum. Spectrum sharing enables operators to opportunistically aggregate spectrum to dynamically support high-bandwidth services. Spectrum sharing can extend the benefits of NR technology to operating entities that may not have access to licensed spectrum.

[0006] 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 send 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 for D2D, V2X, and / or C-V2X on dedicated spectrum, licensed spectrum, and / or unlicensed spectrum. Summary of the invention

[0007] Some aspects of the present disclosure are summarized below to provide a basic understanding of the technology discussed. The present disclosure is not an exhaustive review of all considered features of the present disclosure, and is neither intended to identify the key or important elements of all aspects of the present disclosure, nor is it intended to describe the scope of any or all aspects of the present disclosure. Its sole purpose is to present some concepts of one or more aspects of the present disclosure in the form of an abstract as a preface to the more detailed description presented later.

[0008] For example, in one aspect of the present disclosure, a method of wireless communication includes: performing, by a first user equipment (UE), a listen-before-talk (LBT) in a shared radio frequency band based on a first starting point among multiple starting points within a LBT gap duration; and sending, by the first UE, a first side link communication to a second UE in the shared radio frequency band based on the LBT, the first side link communication including first side link control information (SCI) and first side link data.

[0009] In another aspect of the present disclosure, an apparatus includes: a processor configured to: perform a listen-before-talk (LBT) in a shared radio frequency band based on a first starting point among multiple starting points within a LBT gap duration; and a transceiver configured to send a first side link communication to a second user equipment (UE) in the shared radio frequency band based on the LBT, the first side link communication including first side link control information (SCI) and first side link data.

[0010] In another aspect of the present disclosure, a non-transitory computer-readable medium has program code recorded thereon, the program code comprising: code for causing a first user equipment (UE) to perform a listen-before-talk (LBT) in a shared radio frequency band based on a first starting point among multiple starting points within a LBT gap duration; and code for causing the first UE to send a first side link communication to a second UE in the shared radio frequency band based on the LBT, the first side link communication comprising first side link control information (SCI) and first side link data.

[0011] In another aspect of the present disclosure, an apparatus includes: a unit for performing a listen-before-talk (LBT) in a shared radio frequency band based on a first starting point among multiple starting points within a LBT gap duration; and a unit for sending a first side link communication to a second UE in the shared radio frequency band based on the LBT, the first side link communication including first side link control information (SCI) and first side link data.

[0012] When browsing 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 features of the present invention may be discussed with reference to certain embodiments and figures below, all embodiments of the present invention may include one or more of the preferred features discussed herein. In other words, although one or more embodiments may be discussed as having certain preferred features, one or more of these features may also be used in conjunction with the various embodiments of the present invention discussed herein. In a similar manner, although exemplary embodiments may be discussed below as devices, systems or methods, it should be understood that various devices, systems and methods may be used to implement these exemplary embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A wireless communication network in accordance with some aspects of the present disclosure is shown.

[0014] Figure 2

[0013] A wireless communication network providing sidelink communications in accordance with some aspects of the present disclosure is shown.

[0015] Figure 3 A sidelink communication scheme in a wireless communication network according to some aspects of the present disclosure is shown.

[0016] Figure 4 is a block diagram of a user equipment (UE) according to some aspects of the present disclosure.

[0017] Figure 5 is a block diagram of an exemplary base station (BS) according to some aspects of the present disclosure.

[0018] Figure 6 is a timing diagram illustrating a sidelink listen-before-talk (LBT) scheme according to some aspects of the present disclosure.

[0019] Figure 7 is a timing diagram illustrating a sidelink LBT scheme according to some aspects of the present disclosure.

[0020] Figure 8is a timing diagram illustrating a sidelink LBT scheme according to some aspects of the present disclosure.

[0021] Fig. 9 A sidelink LBT scheme according to some aspects of the present disclosure is shown.

[0022] Fig.10 A sidelink frequency hopping scheme according to some aspects of the present disclosure is shown.

[0023] Fig.11 A flow chart of a sidelink communication method according to some aspects of the present disclosure is shown. DETAILED DESCRIPTION

[0024] The specific embodiments given below in conjunction with the accompanying drawings are intended to be descriptions of various configurations, rather than to represent the only configurations that implement the concepts described herein. Specific details are included in the detailed description to provide a thorough understanding of the various concepts. However, it is obvious to those skilled in the art that these design concepts can be implemented without these specific details. In some instances, the known structures and components shown in the form of block diagrams are to avoid blurring these concepts.

[0025] In general, the present disclosure relates to wireless communication systems, also referred to as wireless communication networks. In various aspects, these techniques and devices can be used for wireless communication networks, such as code division multiple access (CDMA) networks, time division multiple access (TDMA) networks, frequency division multiple access (FDMA) networks, orthogonal FDMA (OFDMA) networks, single carrier FDMA (SC-FDMA) networks, LTE networks, 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" are used interchangeably.

[0026] OFDMA network can realize wireless 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 parts of Universal Mobile Telecommunications System (UMTS). Specifically, Long Term Evolution (LTE) is a version of UMTS 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 various radio technologies and standards are known or under development. For example, the 3rd Generation Partnership Project (3GPP) is a collaboration between telecommunications association groups that aims to define 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 of wireless technologies from LTE, 4G, 5G, NR, etc., which use a new and different set of radio access technologies or radio air interfaces to share access to the wireless spectrum between networks.

[0027] 5G networks encompass multiple deployments, multiple spectrums, and multiple services and devices using a unified OFDM-based air interface. To achieve these goals, in addition to developing new radio technologies for 5G NR networks, additional enhancements to LTE and LTE-A are being considered. 5G NR will be able to extend coverage to provide (1) to large-scale Internet of Things (IoT) with ultra-high density (e.g., ~1M nodes / km2), ultra-low complexity (e.g., tens of bits / second), ultra-low energy consumption (e.g., more than a decade of battery life), and deep coverage that can reach challenging locations; (2) including mission-critical control with strong security for protecting sensitive personal, financial, or confidential information, ultra-high reliability (e.g., ~99.9999% reliability), ultra-low latency (e.g., ~1ms), and a wide range of mobile or lack-of-mobility users; and (3) with enhanced mobile broadband, including extremely high capacity (e.g., ~10Tbps / km 2 ), extremely high data rates (e.g., multi-Gbps rates, 100+Mbps user experienced rates), and deep perception with advanced discovery and optimization.

[0028] 5G NR can be implemented using an optimized OFDM-based waveform with scalable digital parameters and transmission time intervals (TTI); with a common, flexible framework to effectively multiplex services and functions in a dynamic, low-latency time division duplex (TDD) / frequency division duplex (FDD) design; and using advanced wireless technologies such as massive multiple-input multiple-output (MIMO), robust millimeter wave (mmWave) transmission, advanced channel coding, and device-centric mobility. The scalability of digital parameters 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 implemented by less than 3GHz FDD / TDD, the subcarrier spacing may occur at 15kHz, such as over 5, 10, 20MHz and similar bandwidths (BW). For various other outdoor and small cell coverage deployments with 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 5GHz band, subcarrier spacing may occur at 60kHz over 160MHz BW. Finally, for various deployments transmitting with mmWave components at 28GHz TDD, subcarrier spacing may occur at 120kHz over 500MHz BW.

[0029] 5G NR's scalable digital parameters help achieve scalable TTI to meet various latency and quality of service (QoS) requirements. For example, shorter TTI can be used for low latency and high reliability, while longer TTI can be used for higher spectral efficiency. Efficient multiplexing of long TTI and short TTI allows transmission to start from 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 cell-by-cell basis to dynamically switch between UL and downlink to meet current traffic needs.

[0030] The various aspects and features of the present disclosure are further described below. It should be apparent that the teachings of this article can be implemented in a variety of forms, and any specific structure, function or both disclosed herein are merely illustrative and non-restrictive. According to the teachings of this article, 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 implement a method. In addition, other structures, functions, or structures and functions other than one or more aspects of the aspects set forth herein or structures and functions different from one or more aspects of the aspects set forth herein can be used to implement such a device or implement this method. For example, the method can be implemented as a part of a system, device, device, and / or implemented as an instruction stored on a computer-readable medium for execution on a processor or computer. In addition, an aspect can include at least one element of a claim.

[0031] Sidelink communication refers to communication between user equipment devices (UE) without tunneling through a base station (BS) and / or a core network. Sidelink communication can be performed through a physical sidelink control channel (PSCCH) and a physical sidelink shared channel (PSSCH). PSCCH and PSSCH are similar to the physical downlink control channel (PDCCH) and physical downlink shared channel (PDSCH) in downlink (DL) communication between a BS and a UE. For example, the PSCCH can carry sidelink control information (SCI), and the PSSCH can carry sidelink data (e.g., user data). Each PSCCH is associated with a corresponding PSSCH, where the SCI in the PSCCH can carry reservation and / or scheduling information for sidelink data transmission in the associated PSSCH. Use cases for sidelink communication can include vehicle-to-everything (V2X), industrial IoT (IIoT), and / or NR-lite.

[0032] NR supports two modes of radio resource allocation (RRA), Mode 1 RRA and Mode 2 RRA, for sidelinks on licensed spectrum. Mode 1 RRA supports network-controlled RRA that can be used for sidelink communications within coverage. For example, the serving BS can determine radio resources on behalf of the sidelink UE and send an indication of the radio resources to the sidelink UE. Mode 2 RRA supports autonomous RRA that can be used for sidelink UEs outside of coverage or sidelink UEs with partial coverage. For example, a sidelink UE outside of coverage or a partially covered UE can be pre-configured with a sidelink resource pool, and radio resources can be selected from the pre-configured sidelink resource pool for sidelink communications. Sidelink communications using Mode 2 RRA can be referred to as autonomous sidelink communications.

[0033] The deployment of NR on unlicensed spectrum is called NR Unlicensed (NR-U). Some research has been conducted on the deployment of NR-U on the 5 GHz unlicensed band. The Federal Communications Commission (FCC) and the European Telecommunications Standards Institute (ETSI) are working to regulate 6 GHz as a new unlicensed band for wireless communications. The increase in the 6 GHz band allows hundreds of megahertz (MHz) of bandwidth (BW) to be used for unlicensed band communications. In addition, NR-U can also be deployed on the 2.4 GHz unlicensed band currently shared by various radio access technologies (RATs), such as IEEE 802.11 wireless local area networks (WLANs) or WiFi and / or licensed assisted access (LAA). Sidelinks can benefit from utilizing the additional bandwidth available in the unlicensed spectrum.

[0034] The present application describes a mechanism for a sidelink UE to perform autonomous sidelink communication on a shared radio frequency band (e.g., in a shared radio frequency spectrum or an unlicensed spectrum) and coexist with other technologies (e.g., WiFi, LAA). In some aspects, the sidelink system can utilize SCI monitoring or sensing to handle intra-technical conflicts or intra-system conflicts (between sidelink UEs of the same system), and can utilize listen before speaking (LBT) to handle inter-technical conflicts in order to coexist with other technologies. In some aspects, the shared radio frequency band can be divided into multiple subchannels or frequency subbands. The sidelink UE can be configured to operate in mode 2RRA. For example, the sidelink UE can be configured with a resource pool in a shared radio frequency band. The sidelink UE can use a wideband receiver for SCI monitoring or sensing in a resource pool, and can use a narrowband transmitter for channel access based on a frequency subband. In addition, channel access can be in units of sidelink communication frames in time. Each sidelink communication frame can include an LBT gap duration, followed by a sidelink resource. A sidelink UE intended to be transmitted in a frequency subband can perform LBT in the LBT gap duration. If the LBT passes, the sidelink UE may continue to send SCI and / or sidelink data in subsequent sidelink resources.In some aspects, the sidelink system may be a synchronous system, in which the sidelink UE is synchronized in time, for example, based on a synchronization signal block (SSB) received from a base station (BS) or a sidelink UE.

[0035] In some aspects, the LBT gap duration may include multiple LBT starting points to provide prioritized channel access. The LBT starting point refers to the time when the sidelink UE can start performing LBT. The LBT starting points within the LBT gap duration may have reduced channel access or contention priority. For example, an earlier LBT starting point in the LBT gap duration may provide a higher channel access priority than a later LBT starting point in the LBT gap duration.

[0036] In some aspects, the side link UE can reserve one or more LBT starting points in the LBT gap duration, and can indicate the reservation of one or more LBT starting points in the PSCCH SCI. For example, the side link UE can send SCI in the current side link resource to reserve one or more LBT starting points during the LBT gap duration for subsequent side link resources. In some aspects, the SCI can indicate the priority of the reservation. A high priority side link UE (e.g., having a high priority side link service) can reserve an earlier LBT starting point, while a low priority side link UE (e.g., having a low priority side link service) can reserve a later LBT starting point. In some aspects, compared with a low priority side link UE, a high priority UE can reserve a larger number of LBT starting points in the LBT gap duration. In some aspects, a high priority side link UE can reserve all LBT starting points in the LBT gap duration. For example, a high priority side link UE can perform LBT starting at the earliest LBT starting point. When LBT fails, the high priority side link UE can retry LBT at each subsequent LBT starting point. Once LBT is successful, the UE may transmit in the sidelink resources.In some aspects, during the LBT gap duration, the sidelink UE may transmit an SCI to reserve different LBT starting points in different frequency subbands.

[0037] In some aspects, the side link UE may monitor the SCI from the other side link UE. The side link UE may opportunistically cover the low priority LBT starting point reservation made by the other side link UE. In some aspects, the side link UE may be configured with a frequency hopping pattern. After passing LBT and winning the channel occupancy time (COT), the UE may hop from one frequency sub-band to another frequency sub-band side link transmission within the duration of the COT. In some aspects, the side link UE may adjust the channel access occupancy rate (CR) and / or the channel busy rate (CBR) based on the frequency hopping pattern and / or the LBT result, and report the adjusted CBR and / or the adjusted CR to the BS.

[0038] Aspects of the present disclosure may provide several benefits. For example, using LBT before sidelink resources may allow sidelink UEs to coexist with other technologies (e.g., WiFi, LAA). Using multiple LBT starting points within the LBT gap duration may provide prioritized channel access. In addition, by allowing a sidelink UE that fails LBT at an early LBT starting point to retry LBT at a subsequent LBT starting point within the same LBT gap duration, the waste of radio resources due to LBT failure may be reduced. The indication of the LBT starting point reservation in the SCI may reduce intra-system conflicts between sidelink UEs in the sidelink system. The opportunistic coverage of the low-priority LBT starting point reservation may also provide a greater opportunity for high-priority sidelink UEs to obtain access to the channel. The use of subband channel access and / or frequency hopping may make the sidelink system compatible with the provisions in the 2.4 GHz unlicensed band, and thus may allow the sidelink system to be deployed on the 2.4 GHz unlicensed band. Frequency hopping-based and / or LBT-based adjustments to CBR and / or CR calculations may provide a better or more accurate view of channel status within the sidelink system and / or sidelink UE channel utilization, thereby enabling the BS to configure the sidelink UE, resource pool, and / or frequency hopping pattern of the sidelink UE to reduce intra-system conflicts. 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 applied to any suitable shared or unlicensed band.

[0039] Figure 1 A wireless communication network 100 is shown according to some aspects of the present disclosure. The network 100 may be a 5G network. The network 100 includes a plurality of base stations (BSs) 105 (labeled 105a, 105b, 105c, 105d, 105e, and 105f, respectively) 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, etc. Each BS 105 may provide communication coverage for a particular geographic area. In 3GPP, the term "cell" may refer to such a particular geographic coverage area of ​​the BS 105 and / or a BS subsystem serving the coverage area, depending on the context in which the term is used.

[0040] BS 105 may provide communication coverage for macro cells or small cells (such as pico cells or femto cells) and / or other types of cells. Macro cells typically cover a relatively large geographic area (e.g., a radius of several kilometers) and may allow unrestricted access by UEs with service contracts with a network provider. Small cells (such as pico cells) typically cover a relatively small geographic area and may allow unrestricted access by UEs with service contracts with a network provider. Small cells (such as femto cells) also typically 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 femto cells (e.g., UEs in a closed subscriber group (CSG) , UEs of users in a home, etc.). The BS of a macro cell may be referred to as a macro BS. The BS of a small cell may be referred to as a small cell BS, a pico BS, a femto BS, or a home BS. In Figure 1 In the example shown, BS 105d and 105e may be conventional macro BSs, while BS 105a-105c may be macro BSs enabled with one of three-dimensional (3D), full-dimensional (FD), or massive MIMO. BS 105a-105c may utilize its higher-dimensional MIMO capabilities to employ 3D beamforming in elevation and azimuth beamforming to increase coverage and capacity. BS 105f may be a small cell BS, which may be a home node or a portable access point. BS 105 may support one or more (e.g., two, three, four, etc.) cells.

[0041] The network 100 may support synchronous 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.

[0042] UE 115 is scattered throughout the wireless network 100, and each UE 115 can be fixed or mobile. UE 115 can also be referred to as a terminal, a mobile station, a user unit, a station, etc. UE 115 can 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 can be a device including a universal integrated circuit card (UICC). On the other hand, UE can be a device that does not include UICC. In some aspects, UE 115 that does not include UICC can also be referred to as IoT device or 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 can also be a machine specially configured for connection communication, which includes machine type communication (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 mark (e.g., a communication link) represents a wireless transmission between a UE 115 and a serving BS 105 (which is a BS designated to serve the UE 115 on a downlink (DL) and / or uplink (UL)), a desired transmission between BSs 105, a backhaul transmission between BSs, or a sidelink transmission between UEs 115.

[0043] In operation, BS 105a-105c may use 3D beamforming and cooperative spatial techniques (e.g., coordinated multipoint (CoMP) or multi-connectivity) to serve UEs 115a and 115b. Macro BS 105d may perform backhaul communications with BS 105a-105c and small cell BS 105f. Macro BS 105d may also transmit multicast services that are subscribed to and received by UEs 115c and 115d. 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.

[0044] 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 radio configuration and scheduling for communicating with the UE 115. In various examples, the BSs 105 may communicate with each other directly or indirectly (e.g., via the core network) via a backhaul link 134, which may be a wired or wireless communication link (e.g., X1, X2, etc.).

[0045] The network 100 may also support mission-critical communications through 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 a BS (e.g., small cell BS 105f and macro BS 105e) through the network 100, or in a multi-step configuration by communicating with another user device that relays its information to the network (e.g., UE 115f transmits temperature measurement information to smart meter UE 115g, which then reports the information to the network through small cell BS 105f). The network 100 can 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.

[0046] In some embodiments, the network 100 communicates using an OFDM-based waveform. An OFDM-based system can divide the system BW into multiple (K) orthogonal subcarriers, which are also commonly referred to as tones, frequency bands, etc. Each subcarrier can be modulated with data. In some instances, the subcarrier spacing between adjacent subcarriers can be fixed, and the total number of subcarriers (K) can depend on the system BW. The system BW can also be divided into subbands. In other cases, the subcarrier spacing and / or TTI duration can be scalable.

[0047] In some aspects, BS 105 may allocate 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 BS 105 to UE 115, while UL refers to the transmission direction from UE 115 to BS 105. Communication may be in the form of radio frames. A radio frame may be divided into a plurality of (e.g., approximately 10) subframes. Each time slot may be further divided into micro-time slots. In FDD mode, simultaneous UL and DL transmissions may occur in different frequency bands. For example, each subframe includes a UL subframe in a UL band and a DL subframe in a DL band. In TDD mode, UL and DL transmissions are performed using the same frequency band in different time periods. For example, a subset of subframes in a radio frame (e.g., DL subframes) may be used for DL ​​transmissions, and another subset of subframes in a radio frame (e.g., UL subframes) may be used for UL transmissions.

[0048] DL subframes and UL subframes can be further divided into several areas. For example, each DL or UL subframe can have a predetermined area for transmitting reference signals, control information and data. Reference signals are predetermined signals that facilitate communication between BS 105 and UE 115. For example, reference signals can have a specific pilot pattern or structure, wherein pilot tones can span operating BW or frequency bands, and each pilot tone is placed at a predefined time and a predefined frequency. For example, BS 105 can send a cell-specific reference signal (CRS) and / or a channel state information-reference signal (CSI-RS) to enable UE 115 to estimate the DL channel. Similarly, UE 115 can send a sounding reference signal (SRS) to enable BS 105 to estimate the UL channel. Control information may include resource allocation and protocol control. Data may include protocol data and / or operating data. In some aspects, BS 105 and UE 115 can use self-contained subframes for communication. 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 longer DL communication duration than UL communication. A UL-centric subframe may include a longer UL communication duration than UL communication.

[0049] 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), residual system information (RMSI), and other system information (OSI)) to facilitate initial network access. In some instances, the BS 105 may broadcast the PSS, SSS, and / or MIB in the form of a synchronization signal block (SSB) on a physical broadcast channel (PBCH), and may broadcast the RMSI and / or OSI on a physical downlink shared channel (PDSCH).

[0050] 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 periodic 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, which may be combined with a physical layer identification value to identify a cell. The PSS and SSS may be located in the center portion of a carrier or any suitable frequency within a carrier.

[0051] 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 a random access channel (RACH) procedure, paging, a control resource set (CORESET) for physical downlink control channel (PDCCH) monitoring, a physical UL control channel (PUCCH), a physical UL shared channel (PUSCH), power control, and SRS.

[0052] 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 fallback indicator. After 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, RAR, connection request, and 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.

[0053] After establishing the connection, the UE 115 and the BS 105 may enter a normal operation phase, in which operation data may be exchanged. For example, the BS 105 may schedule the UE 115 for UL and / or DL ​​communications. The BS 105 may send an UL and / or 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 PUCCH according to the UL scheduling grant.

[0054] In some aspects, BS 105 may communicate with UE 115 using HARQ technology to improve communication reliability, for example, to provide URLLC services. BS 105 may schedule UE 115 for PDSCH communication by sending DL grants in PDCCH. BS 105 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 BS 105. Conversely, if UE 115 fails to successfully receive the DL transmission, UE 115 may send HARQ NACK to BS 105. After receiving HARQ NACK from UE 115, BS 105 may resend the DL data packet to UE 115. The retransmission may include a coded version of the DL data that is the same as the initial transmission. Alternatively, the retransmission may include a coded 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 to DL HARQ.

[0055] 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 allocate the UE 115 to operate on a specific BWP (e.g., a specific part of the system BW). The allocated BWP may be referred to as an active BWP. The UE 115 may monitor the active BWP to obtain signaling information from the BS 105. The BS 105 may schedule the UE 115 for UL or DL ​​communication in the active BWP. In some aspects, the BS 105 may allocate a pair of BWPs within the CC to the UE 115 for UL and DL communication. For example, the BWP pair may include a BWP for UL communication and a BWP for DL ​​communication.

[0056] 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, BS 105 and UE 115 may be operated by multiple network operating entities. In order to avoid conflicts, BS 105 and UE 115 may use a listen before talk (LBT) process to monitor transmission opportunities (TXOPs) in a shared channel. TXOP may also be referred to as COT. For example, a transmitting node (e.g., BS 105 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 avoid transmitting in the channel.

[0057] LBT can be based on energy detection (ED) or signal detection. For LBT based on energy detection, LBT passes when the signal energy measured from the channel is below a threshold. On the contrary, LBT fails when the signal energy measured from the channel exceeds a threshold. For LBT based on signal detection, LBT passes when a channel reservation signal (e.g., a predetermined preamble signal) is not detected in the channel. In addition, LBT can be in multiple modes. The LBT mode can be, for example, Category 4 (CAT4) LBT, Category 2 (CAT2) LBT, or Category 1 (CAT1) LBT. CAT1 LBT is referred to as a no-LBT mode, in which LBT is not performed before transmission. CAT2 LBT refers to LBT without a random backoff period. For example, a transmitting node can 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 LBT with a random backoff and a variable contention window (CW). For example, a transmitting node can derive a random number and backoff during a certain duration based on a random number derived in a certain time unit.

[0058] 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 licensed assisted access (LAA). Figure 2 shown.

[0059] Figure 2An example of a wireless communication network 200 providing sidelink communications according to aspects of the present disclosure is shown. Network 200 may correspond to a portion of network 100. Although it will be appreciated that aspects of the present disclosure may be scaled to any suitable number of UEs 215 (e.g., approximately 2, 3, 4, 5, 7, or more) and / or BSs 205 (e.g., approximately 1, 3, or more), for purposes of simplifying discussion, Figure 2 Two BSs 205 (shown as 205a and 205b) and six UEs 215 (shown as 215a1, 215a2, 215a3, 215a4, 215b1, and 215b2) are shown. BS 205 and UE 215 may be similar to BS 105 and UE 115, respectively. BS 205 and UE 215 may share the same radio frequency band for communication. In some instances, the radio frequency band may be a 2.4 GHz unlicensed band, a 5 GHz unlicensed band, or a 6 GHz unlicensed band. Generally, the shared radio frequency band may be at any suitable frequency.

[0060] BS 205a and UE 215a1-215a4 may be operated by a first network operation entity. BS 205b and UE 215b1-215b2 may be operated by a second network operation entity. In some aspects, the first network operation entity may utilize the same RAT as the second network operation entity. For example, the BS 205a and UE 215a1-215a4 of the first network operation entity and the BS 205b and UE 215b1-215b2 of the second network operation entity are NR-U devices. In some other aspects, the first network operation entity may utilize a different RAT from the second network operation entity. For example, the BS 205a and UE 215a1-215a4 of the first network operation entity may utilize NR-U technology, while the BS 205b and UE 215b1-215b2 of the second network operation entity may utilize WiFi or LAA technology.

[0061] In network 200, some of 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 of 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 may not communicate directly with BS 205a. In some instances, UE 215a1 can act as a relay for UE 215a2 to reach BS 205a. Similarly, UE 215b1 is within the coverage area 212 of BS 205b and can therefore communicate with BS 205b and can act as a relay for UE 215b2 to reach BS 205b. In some aspects, some UEs 215 are associated with vehicles (e.g., similar to UEs 115i-k), and communications through side links 251, 252, and 254 can be C-V2X communications. C-V2X communications can refer to communications between a vehicle and any other wireless communication device in a cellular network.

[0062] As discussed above, NR supports autonomous RRA in Mode 2 for sidelink. In the current NR sidelink framework, the sidelink UE can indicate sidelink resource reservation via SCI, and intra-NR sidelink conflicts (between NR sidelink UEs) are controlled via SCI sensing. The present disclosure provides techniques for NR-U sidelink UEs configured with Mode 2 RRA to communicate on a shared radio frequency band or an unlicensed band and coexist with other RATs.

[0063] Figure 3 A sidelink communication scheme 300 in a wireless communication network according to some aspects of the present disclosure is shown. Scheme 300 may be employed by a UE (e.g., UE 115 and / or 215) in a network (e.g., network 100 and / or 200). 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) used for sidelink communication. Figure 2 As discussed in , a shared radio frequency band can be shared by multiple RATs. Figure 3 In this example, the x-axis represents time in some arbitrary units, and the y-axis represents frequency in some arbitrary units.

[0064] 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 about 80 megahertz (MHz) divided into about fifteen 5 MHz frequency sub-bands 302.

[0065] 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, for example, Figure 3 As shown, there may be a frequency gap or guard band between adjacent frequency sub-bands 302 to mitigate interference from adjacent frequency bands. Thus, multiple sidelink data may be transmitted simultaneously in different frequency sub-bands 302 (e.g., FDM). The frame structure 304 also repeats in time. For example, the frame structure 304 may be used to separate the frequency sub-bands 302 from each other. S2 The time is divided into multiple frames. 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. After winning the contention, the sidelink UE can use the sidelink resource 306 to transmit control and user data.

[0066] The sidelink resources 306 may have a structure substantially similar 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 PSCCH 320, PSSCH 330, and / or a physical sidelink feedback channel (PSFCH) 340. PSCCH 320, PSSCH 330, and PSFCH 340 may be multiplexed in time and / or frequency. Figure 3In the example shown, the PSCCH 320 is located during the beginning symbol (eg, approximately 1 symbol or approximately 2 symbols) of the side link resource 306 and occupies the frequency subband 302. S2 PSFCH 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.

[0067] 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. As an example, the sidelink UE may transmit in frequency subband 302 during LBT gap duration 310. S2 LBT can be performed 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 can continue 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 can avoid transmitting in the sidelink resource 306. In this way, LBT can operate to select the frequency subband 302 S2 and promote coexistence with other technologies sharing the frequency band 301.

[0068] 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, driving 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 to the 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 NR intra-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 NR intra-frame sharing. For example, if the NR inner sidelink UE detects that the SCI indicates a reservation for the sidelink resources 306, the NR inner sidelink UE may avoid transmitting in the reserved sidelink resources 306. If the NR inner sidelink UE determines that no reservation for the sidelink resources 306 is detected, the NR inner sidelink UE may transmit in the sidelink resources 306. In this way, SCI sensing may help the UE identify the target frequency subband 302 to reserve for sidelink communication and avoid conflicts (e.g., intra-NR conflicts) with another sidelink UE in the NR sidelink system. In some aspects, the RAT inner sidelink UE may be configured with a sensing window for SCI sensing or monitoring to reduce intra-NR conflicts.

[0069] 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. Therefore, 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 receiver based on the destination ID. If the sidelink UE is the target receiver, the sidelink UE may continue to receive and decode the sidelink data indicated by the SCI.

[0070] 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). The sidelink UE can perform synchronization in various forms based on a sidelink SSB received from the sidelink UE and / or a NR-U SSB received from a BS (e.g., BS 105 and / or 205), for example, 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 framework structure 304. The BS may configure the side link UE with a resource pool configuration indicating resources in the frequency band 301 and / or subband 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).

[0071] In some regions, government agencies may regulate LBT operations and / or transmissions in unlicensed spectrum (e.g., the 2.4 GHz band). For example, a wireless device may transmit with a maximum duration of up to about 5 ms and an interval of about 5 ms between transmissions in the 2.4 GHz band without performing LBT. However, if the wireless device accesses the 2.4 GHz band after LBT, the wireless device may utilize a COT of about 5 ms to about 13 ms. In addition, if the wireless device accesses the 2.4 GHz band after LBT and utilizes frequency hopping for transmission, the wireless device may utilize a COT of up to about 80 milliseconds. Thus, as shown in scheme 300 in the 2.4 GHz band, the use of LBT in the NR side link framework may allow the side link to occupy a shared channel for a longer duration. In addition, scheme 300 may be combined with frequency hopping for side link transmissions to further extend the duration of the COT when operating in the 2.4 GHz band. For example, as discussed in greater detail herein, a sidelink UE may hop from one frequency subband 302 in one duration to another frequency subband 302 in the next duration to transmit within the COT.

[0072] Figure 4 400 according to some aspects of the present disclosure. Figure 1 UE 115 discussed in or above Figure 24. As shown, UE 400 may include a processor 402, a memory 404, a sidelink communication module 408, a transceiver 410 including a modem subsystem 412 and a radio frequency (RF) unit 414, and one or more antennas 416. These elements may communicate with each other directly or indirectly (e.g., via one or more buses).

[0073] The processor 402 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 402 may also be implemented as a combination of computing devices, for example, 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.

[0074] Memory 404 may include cache memory (e.g., cache memory of processor 402), 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 nonvolatile memory, or a combination of different types of memory. In one aspect, memory 404 includes a non-transitory computer-readable medium. Memory 404 may store or have recorded thereon instructions 406. Instructions 406 may include instructions that, when executed by processor 402, cause processor 402 to perform aspects of the present disclosure described herein (e.g., Figure 1-Figure 3 and Figure 6-Figure 11 Instructions 406 may also be referred to as program code. The program code may be used to cause the wireless communication device to perform the operations, such as by causing one or more processors (e.g., processor 402) to control or command the wireless communication device to perform the operations. 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, processes, etc. "Instructions" and "code" may include a single computer-readable statement or multiple computer-readable statements.

[0075] The sidelink communication module 408 may be implemented via hardware, software, or a combination thereof. For example, the sidelink communication module 408 may be implemented as a processor, circuit, and / or instructions 406 stored in the memory 404 and executed by the processor 402. In some examples, the sidelink communication module 408 may be integrated within the modem subsystem 412. For example, the sidelink communication module 408 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 412.

[0076] The sidelink communication module 408 may be used in various aspects of the present disclosure, for example, Figure 1-Figure 3 and Figure 6-Figure 11 For example, the sidelink communication module 408 is configured to operate in Mode 2 RRA for sidelink communication (e.g., using Figure 3 The sidelink communication module 408 is configured to transmit SCI (e.g., via PSCCH) and sidelink data (e.g., via PSSCH) in the sidelink resource when LBT passes (e.g., when the channel signal energy measurement result is below the energy detection threshold). Alternatively, the sidelink communication module 408 is configured to avoid transmitting in the sidelink resource when LBT fails (e.g., when the channel signal energy measurement result is above the energy detection threshold).

[0077] In some aspects, the sidelink communication module 408 is configured to select a first LBT starting point from a plurality of LBT starting points within the LBT gap duration to start LBT, for example, based on the priority of the sidelink data. For example, if the sidelink data has a high priority, the sidelink communication module 408 is configured to select an earlier LBT starting point within the LBT gap duration. Alternatively, if the sidelink data has a low priority, the sidelink communication module 408 is configured to select a later LBT starting point within the LBT gap duration.

[0078] In some aspects, the sidelink communication module 408 is configured to: reserve one or more LBT starting points in the next LBT gap duration (of a subsequent sidelink communication frame) on one or more frequency subbands, for example, based on the priority of the sidelink data to be sent in the subsequent sidelink communication frame; generate an SCI including a reservation and a reservation priority; monitor SCIs from other sidelink UEs indicating LBT starting point reservations; and determine whether to override the detected LBT starting point reservation based on a comparison between the priority of the detected reservation and the priority of the sidelink data to be sent in the subsequent sidelink communication frame.

[0079] In some aspects, the sidelink communication module 408 is configured to: perform frequency hopping in the sidelink communication according to the frequency hopping pattern when passing through LBT; calculate the CBR and / or CR based on the frequency hopping pattern and / or LBT results. In some aspects, the sidelink communication module 408 is configured to: receive SSB from a BS (e.g., BS 105 and / or 205); receive SSB from a sidelink UE (e.g., UE 115 and / or 215); perform synchronization based on the received SSB; receive a sidelink configuration indicating a resource pool (e.g., resource pool 308), a frequency hopping pattern, and / or a sidelink communication frame structure (e.g., frame structure 304) from the BS; perform LBT and / or sidelink communication according to the received sidelink configuration. The mechanism for performing sidelink communication on a shared radio frequency band or an unlicensed band using LBT and a mode 2 RRA mechanism is described in more detail herein.

[0080] As shown, the transceiver 410 may include a modem subsystem 412 and an RF unit 414. The transceiver 410 may be configured to communicate bidirectionally with other devices such as the BS 105. The modem subsystem 412 may be configured to modulate and / or encode data from the memory 404 and / or the sidelink communication module 408 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 polar coding scheme, a digital beamforming scheme, etc.). The RF unit 414 may be configured to process (e.g., perform analog-to-digital conversion or digital-to-analog conversion, etc.) the modulated / encoded data (on outbound transmissions) from the modem subsystem 412 or the modulated / encoded data (SCI, sidelink data, LBT starting point reservation, frequency hopping-aware CBR, LBT-aware CR, and / or frequency hopping and LBT-aware CR) of a transmission originating from another source such as the UE 115 or the BS 105. The RF unit 414 may also be configured to perform analog beamforming in conjunction with digital beamforming.Although shown as integrated together in the transceiver 410, the modem subsystem 412 and the RF unit 414 may be separate devices that are coupled together at the UE 115 to enable the UE 115 to communicate with other devices.

[0081] The RF unit 414 can provide modulated and / or processed data, such as data packets (or more generally, data messages that can contain one or more data packets and other information) to the antenna 416 for transmission to one or more other devices. The antenna 416 can also receive data messages sent from other devices. The antenna 416 can provide the received data message for processing and / or demodulation at the transceiver 410. The transceiver 410 can provide the demodulated and decoded data (e.g., side link configuration, resource pool configuration, frequency hopping mode, CBR / CR report configuration) to the side link communication module 408 for processing. The antenna 416 can include multiple antennas with similar or different designs to maintain multiple transmission links. The RF unit 414 can configure the antenna 416.

[0082] In some aspects, the transceiver 410 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, for example, by cooperating with the side link communication module 408, send a first side link communication to a second UE (e.g., UE 115, 215 and / or 400) in the shared RF band based on LBT, the first side link communication including a first SCI and first side link data.

[0083] In one aspect, the UE 400 may include multiple transceivers 410 that implement different RATs (e.g., NR and LTE). In one aspect, the UE 400 may include a single transceiver 410 that implements multiple RATs (e.g., NR and LTE). In one aspect, the transceiver 410 may include various components, where different combinations of components may implement different RATs.

[0084] Figure 5 is a block diagram of an exemplary BS 500 according to some aspects of the present disclosure. BS 500 may be as described above in Figure 1 BS 105 of the network 100 discussed in Figure 2 200 in the network 200 discussed in the previous section. As shown, BS 500 may include a processor 502, a memory 504, a sidelink configuration module 508, a transceiver 510 including a modem subsystem 512 and an RF unit 514, and one or more antennas 516. These elements may communicate with each other directly or indirectly (e.g., via one or more buses).

[0085] The processor 502 may have various characteristics as a particular type of processor. For example, these 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 502 may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0086] The memory 504 may include cache memory (e.g., cache memory of the processor 502), 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 504 may include non-transitory computer-readable media. The memory 504 may store instructions 506. The instructions 506 may include instructions that, when executed by the processor 502, cause the processor 502 to perform the operations described herein (e.g., Figure 1-Figure 3 and Figure 6-Figure 11 Instructions 506 may also be referred to as code, which may be broadly interpreted as including the above instructions for Figure 4 Any type of computer-readable statement in question.

[0087] The sidelink configuration module 508 may be implemented via hardware, software, or a combination thereof. For example, the sidelink configuration module 508 may be implemented as a processor, circuit, and / or instructions 506 stored in the memory 504 and executed by the processor 502. In some examples, the sidelink configuration module 508 may be integrated within the modem subsystem 512. For example, the sidelink configuration module 508 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 512.

[0088] The sidelink configuration module 508 may be used in various aspects of the present disclosure, for example, Figure 1-Figure 3 and Figure 6-Figure 11 . For example, the side link configuration module 508 is configured to: send a side link configuration indicating a side link resource pool, a frequency hopping pattern to a UE (e.g., UE 115, 215, and / or 400) and / or send an SSB to it to facilitate synchronization at the UE. The side link configuration may indicate a time-frequency resource (e.g., frequency band 301, frequency subband 302, side link communication frame structure 304, an allowed LBT starting point within the LBT gap duration) and / or a side link service priority category for the side link resource pool. The frequency hopping pattern may indicate a frequency subband sequence in which the UE performs frequency hopping during transmission within a channel dwell time (e.g., COT). In some aspects, the side link configuration module 508 is configured to send a CBR and / or CR report configuration to the UE, receive a CBR report from the UE that is aware of frequency hopping, a CR report that is aware of LBT, and / or a CR report that is aware of frequency hopping and LBT, and / or control a conflict within the side link. For example, the side link configuration module 508 is configured to adjust the frequency hopping pattern at the UE. Mechanisms for configuring a sidelink UE for channel access in a shared radio frequency band and / or an unlicensed band are described in greater detail herein.

[0089] As shown, the transceiver 510 may include a modem subsystem 512 and an RF unit 514. The transceiver 510 may be configured to communicate bidirectionally with other devices (e.g., UE 115 and / or UE 400 and / or another core network unit). The modem subsystem 512 may be configured to modulate and / or encode data according to an MCS (e.g., an LDPC coding scheme, a turbo coding scheme, a convolutional coding scheme, a polar coding scheme, a digital beamforming scheme, etc.). The RF unit 514 may be configured to process (e.g., perform analog-to-digital conversion or digital-to-analog conversion, etc.) the modulated / encoded data (on outbound transmission) from the modem subsystem 512 or the modulated / encoded data (e.g., PDCCH, PDSCH, SSB, sidelink configuration, sidelink resource pool configuration, SSB, frequency hopping pattern for sidelink communication) of a transmission originating from another source (e.g., UE 115 and / or UE 400). RF unit 514 may also be configured to perform analog beamforming in conjunction with digital beamforming.Although shown as integrated together in transceiver 510, modem subsystem 512 and / or RF unit 514 may be separate devices coupled together at BS 105 to enable BS 105 to communicate with other devices.

[0090] The RF unit 514 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 516 for transmission to one or more other devices. According to some aspects of the present disclosure, this may include, for example, transmitting information to complete attachment to the network and communication with the resident UE 115 or UE 400. The antenna 516 may also receive data messages sent from other devices and provide the received data messages for processing and / or demodulation at the transceiver 510. The transceiver 510 may provide demodulated and decoded data (e.g., CBR reports aware of frequency hopping, CR reports aware of LBT, and / or CR reports aware of frequency hopping and LBT) to the sidelink configuration module 508 for processing. The antenna 516 may include multiple antennas with similar or different designs to maintain multiple transmission links.

[0091] In one aspect, the BS 500 may include multiple transceivers 510 that implement different RATs (e.g., NR and LTE). In one aspect, the BS 500 may include a single transceiver 510 that implements multiple RATs (e.g., NR and LTE). In one aspect, the transceiver 510 may include various components, where different combinations of components may implement different RATs.

[0092] Figure 66 is a timing diagram illustrating a sidelink LBT scheme 600 according to some aspects of the present disclosure. Scheme 600 may be employed by a UE (e.g., UE 115, 215, and / or 400) in a network (e.g., network 100 and / or 200). Specifically, as shown in scheme 600, the UE may perform LBT in a shared channel (e.g., frequency band 301 and / or frequency subband 302) for sidelink transmissions. Figure 6 In the example, the x-axis represents time in some arbitrary unit. Figure 3 The side link frame structure 304 is described similar to that in FIG. 1 and for simplicity, the same side link frame structure 304 may be used. Figure 3 The same reference numerals are used in the drawings.

[0093] In scheme 600, the LBT gap duration 310 may include multiple LBT starting points 610 (shown as 610a, 610b, and 610c). The LBT starting point 610 refers to the time when the sidelink UE can start performing LBT. Each LBT starting point 610 corresponds to the starting point of the CCA slot 602. As shown, the LBT starting point 610a is located at the beginning of the CCA slot 602a, the LBT starting point 610c is located at the beginning of the CCA slot 602c, and the LBT starting point 610c is located at the beginning of the CCA slot 602c. The duration of the CCA slot 602 refers to the duration when the sidelink UE can monitor the channel (e.g., perform signal energy measurement) to determine whether the channel is busy or available. When the channel signal energy measurement result in the CCA slot 602 is higher than a threshold, the channel is busy. When the channel signal energy measurement within the duration of the CCA slot 602 is lower than a threshold, the channel is available. For simplicity of illustration and discussion, Figure 6 Three LBT starting points 610a, 610b, and 610c are shown at the beginning of CCA slots 602a, 602b, and 602c, respectively, in the LBT gap duration 310. However, the LBT gap duration may include any suitable number of LBT starting points 610 and corresponding CCA slots 602 (e.g., approximately 2, 4, or more).

[0094] A sidelink UE with high priority data for transmission may select an earlier LBT starting point, while a sidelink UE with low priority data for transmission may select a later LBT starting point. A sidelink UE with data to be sent may perform LBT starting at the LBT starting point 610. The transmitting UE may monitor the channel (e.g., perform channel energy measurements) for the duration of the corresponding CCA slot 602. If the channel is idle during the CCA slot 602 (e.g., the channel signal energy measurement result is below a threshold), the LBT is passed and the UE may continue to transmit in the shared channel. If the channel is detected to be busy during the CCA slot 602 (e.g., the channel signal measurement result is above a threshold), the LBT fails and the UE may avoid transmitting in the shared channel. If a high priority UE passes LBT at an earlier LBT starting point 610 (e.g., LBT starting point 610a), the high priority UE may continue to transmit in the channel, thereby possibly preventing a low priority UE from initiating LBT at a subsequent LBT starting point 610 (e.g., LBT starting point 610b). Thus, using multiple LBT starting points 610 may help control intra-technology conflicts (e.g., between NR sidelink UEs).

[0095] In some aspects, after the high priority sidelink UE passes the LBT at the end of the CCA slot 602a (e.g., at time T0), the sidelink UE may send a fill signal to occupy the channel until the time when the sidelink resource 306 starts (e.g., at time T1). In other words, the fill signal may start at the next LBT starting point 610b and continue to the beginning of the sidelink resource 306. The sidelink UE may send a sidelink transmission aligned with a predetermined boundary or predetermined starting point (e.g., an SCI start symbol boundary) of the sidelink resource 306. The predetermined boundary may be a common boundary across all sidelink UEs in the sidelink system or network (e.g., based on synchronization with an SSB sent by a BS (e.g., BS 105, 205 and / or 500) or a sidelink UE). In this way, the monitoring UE may start SCI monitoring or sensing at the sidelink resource 306 boundary. The fill signal starting at the LBT start point 610b and continuing to the start of the side link resource 306 can select other UEs or devices that start LBT at subsequent LBT start points 610b or 610c so that they do not access the channel. In some instances, the fill signal can be a predetermined sequence or a predetermined signal waveform (e.g., to facilitate detection at a monitoring or receiving UE).

[0096] In some other aspects, the sidelink UE passing through the LBT may start the sidelink transmission immediately. For example, when passing through the LBT at time T0, the sidelink UE may start the sidelink transmission at time T0. In other words, the sidelink resource 306 may start at an earlier time (e.g., at time T0). Thus, when Figure 3 When scheme 300 is used together with frequency subband 302 as shown, the SCI monitoring or sensing UE may have different SCI monitoring or sensing start times for different frequency subbands (e.g., frequency subband 302). For example, the SCI monitoring or sensing start time across frequency subband 302 may have a zigzag shape. Therefore, although the instant side link transmission may be more efficient in utilizing resources, it may be more complicated for SCI sensing. For example, a peer UE or other side link UE may perform continuous monitoring and search for SCI at different boundaries because the monitoring UE may not know when the sending UE can pass the LBT. In some instances, when passing the LBT at time T0, the side link UE may start PSSCH side link data transmission at time T0 and send SCI at the boundary of the side link resource, so the monitoring side link UE may perform SCI sensing on the side link resource boundary. However, the target receiving side link UE may have to buffer the received signal and decode the side link data from the buffered signal after detecting the SCI and determining that the PSSCH side link data transmission destination is the target receiving side link UE.

[0097] In some aspects, after a high priority UE fails LBT at an early LBT starting point (e.g., LBT starting point 610a), the high priority UE may perform another LBT at a subsequent LBT starting point (e.g., LBT starting point 610b). In other words, the high priority UE may have multiple contention opportunities. The high priority UE may perform LBT from the earliest LBT starting point (e.g., LBT starting point 610a) to the latest LBT starting point (e.g., LBT starting point 610c) in the LBT interval duration (e.g., LBT interval duration 310), and may access the channel after a successful LBT. In contrast, a low priority UE may have a single contention opportunity to perform LBT at the latest LBT starting point (e.g., LBT starting point 610c) within the LBT gap duration 310.

[0098] In some aspects, the CCA time slots 602 within the LBT duration 310 can have the same duration. In other aspects, the CCA time slots 602 within the LBT duration 310 can have different durations. Figure 6In the example shown, the CCA slots 602 have different durations, wherein an earlier CCA slot has a shorter duration compared to a later CCA slot 602. In other words, the CCA slots 602 in the LBT gap duration 310 have an increased duration. For example, the CCA slot 602a may have a duration of approximately 1 OFDM symbol (e.g., approximately 35 μs long), the CCA slot 602b may have a duration of approximately 2 symbols, and the CCA slot 602c may have a duration of approximately 3 symbols. Increasing the CCA slot duration may also provide a higher priority sidelink UE with a greater opportunity to gain access to a shared channel using an earlier CCA slot 602. In other words, the CCA slot 602 and / or the LBT starting point 610 may have a reduced priority in the LBT gap duration 310 (e.g., approximately 35 μs long). Figure 6 In some instances, the later CCA slots 602b and 602c having longer durations in the LBT gap duration 310 may be referred to as extended CCA (eCCA) slots.

[0099] Figure 7 7 is a timing diagram illustrating a sidelink LBT scheme 700 according to some aspects of the present disclosure. Scheme 700 may be employed by a UE (e.g., UE 115 and / or 215) in a network (e.g., network 100 and / or 200). Specifically, as shown in scheme 700, the UE may perform LBT in a shared channel (e.g., frequency band 301 and / or frequency subband 302) for sidelink transmissions. Figure 7 In the example, the x-axis represents time in some arbitrary unit. Figure 3 The side link frame structure 304 is described similar to that in FIG. 1 and for simplicity, the same side link frame structure 304 may be used. Figure 3 The same reference numerals are used in the drawings.

[0100] In scheme 700, a sidelink UE (e.g., UE 115 and / or 215) may reserve one or more LBT starting points in the LBT gap duration 310 at a subsequent time. Figure 7In the example shown, the sidelink UE passes LBT during the LBT gap duration 310a in the time period 702a. The sidelink UE sends SCI 710 in the PSCCH 320 of the sidelink resource 306a, and can send sidelink data in the PSSCH 330 of the sidelink resource 306a. The SCI 710 can indicate the reservation of one or more LBT starting points 610 within the LBT gap duration 310b in the next time period 702b. In some instances, as shown by the dotted arrows, the SCI 710 can reserve all LBT starting points 610a, 610b, and 610c. Generally, the SCI can randomly reserve one or more of the multiple LBT starting points for opportunistic LBT within the LBT interval duration in a TDM manner.

[0101] In some aspects, the sidelink UE may determine which of the multiple LBT starting points 610 in the LBT gap duration 310b to reserve based on the priority of the sidelink data to be transmitted in the PSSCH 330 of the sidelink resource 306b in the time period 702b. The higher the priority of the sidelink data, the earlier LBT starting point 610 may be reserved for channel access. In this regard, if the sidelink data has a high priority, the sidelink UE may reserve the LBT starting point 610a in the LBT gap duration 310b and include the reservation of the LBT starting point 610a in the SCI 710. Alternatively, if the sidelink data has a low priority, the sidelink UE may reserve a subsequent LBT starting point 610c in the LBT gap duration 310b and include the reservation of the LBT starting point 610c in the SCI 710. In some aspects, the higher the priority of the sidelink data, the more number of LBT starting points 610 or a larger set of LBT starting points 610 may be reserved for channel access. In this regard, if the sidelink data has a high priority, the sidelink UE may reserve two LBT starting points 610 (e.g., LBT starting points 610a and 610b) in the LBT gap duration 310b and include the reservation of the two LBT starting points 610 in the SCI 710. Alternatively, if the sidelink data has a low priority, the sidelink UE may reserve fewer LBT starting points 610 (e.g., a single LBT starting point 610c) and include the reservation of the LBT starting point 610c in the SCI 710. In some instances, when the sidelink data to be transmitted has a high priority, the sidelink UE may reserve all LBT starting points 610 (e.g., LBT starting points 610a, 610b, and 610c) in the LBT gap duration 310b for channel access.

[0102] Figure 88 is a timing diagram illustrating a sidelink LBT scheme 800 according to some aspects of the present disclosure. Scheme 800 may be employed by a UE (e.g., UE 115 and / or 215) in a network (e.g., network 100 and / or 200). Specifically, as shown in scheme 800, the UE may perform LBT in a shared channel (e.g., frequency band 301 and / or frequency subband 302) for sidelink transmissions. Figure 8 In the example, the x-axis represents time in some arbitrary unit. Figure 3 The side link frame structure 304 is described similar to that in FIG. 1 and for simplicity, the same side link frame structure 304 may be used. Figure 3 The same reference numerals are used in the drawings.

[0103] In scheme 800, when a subsequent LBT starting point 610 is reserved by another side link UE B, side link UE A (e.g., UE 115 and / or 215) can reserve an earlier LBT starting point 610 within the LBT gap duration 310. In other words, scheme 800 allows opportunistic coverage of low priority reservations. Figure 8 In the example shown, sidelink UE B passes LBT during the LBT gap duration 310a in time period 802a. Sidelink UE B sends SCI 810 in PSCCH 320 of sidelink resource 306a and may send sidelink data in PSSCH 330 of sidelink resource 306a. As shown by dashed arrow 801, SCI 810 indicates a reservation for LBT starting point 610c in LBT gap duration 310c during time period 802c. In some instances, SCI 810 may include an indication of the priority of the sidelink data to be sent in sidelink resource 306c in time period 802c.

[0104] Subsequently, sidelink UE A passes LBT during the LBT gap duration 310b in time period 802b. Sidelink UE A sends SCI 812 in PSCCH 320 of sidelink resource 306b, and can send sidelink data in PSSCH 330 of sidelink resource 306b. Sidelink UE A can determine that the sidelink data to be sent in sidelink resource 306c during time period 802c has a higher priority than the reservation indicated by SCI 810. Therefore, sidelink UE A can reserve an earlier LBT starting point (e.g., LBT starting point 610a) than the LBT starting point 610c reserved by sidelink UE B in LBT gap duration 310c. Sidelink UE A includes a reservation for LBT starting point 610a in SCI 812, as shown by dashed arrow 803. Similarly, the SCI 812 may additionally include an indication of the priority of the sidelink data to be transmitted in the sidelink resource 306c during the time period 802c.

[0105] During time period 802c, high priority sidelink UE A may begin performing LBT starting from the reserved LBT starting point 610a. If sidelink UE A wins the contention (e.g., LBT is passed), sidelink UE A may begin transmitting in the channel (e.g., filler signal or SCI), as described above with reference to Figure 6 As discussed in scheme 600. Therefore, the low priority sidelink UE B may not be able to pass the LBT starting at the later LBT starting point 610c. In some instances, during the time when the high priority sidelink UE A performs CCA or LBT (e.g., in CCA slot 602a), the channel may be busy, and thus the LBT of the high priority UE A may fail. When the low priority UE B performs CCA or LBT, the channel may subsequently be available during that time (e.g., in CCA slot 602c), and thus the low priority sidelink UE may not pass the LBT and gain access to the channel.

[0106] Fig. 9 A sidelink LBT scheme 900 according to some aspects of the present disclosure is shown. Scheme 900 may be employed by a UE (e.g., UE 115 and / or 215) in a network (e.g., network 100 and / or 200). Specifically, as shown in scheme 900, the UE may perform LBT in a shared channel (e.g., frequency band 301 and / or frequency subband 302) for sidelink transmissions. Fig. 9 In the example, the x-axis represents time in some arbitrary units and the y-axis represents frequency in some arbitrary units. Figure 3 The side link frame structure 304 is described similar to that in FIG. 1 and for simplicity, the same side link frame structure 304 may be used. Figure 3The same reference numerals are used in the drawings.

[0107] In scheme 900, a sidelink UE (e.g., UE 115 and / or 215) may reserve different LBT starting points at different frequency sub-bands within a channel or frequency band. Fig. 9 In the example shown, the sidelink UE passes LBT during the LBT gap duration 310a in time period 902a. The sidelink UE sends SCI 910 in the PSCCH 320 of the sidelink resource 306a and may send sidelink data in the PSSCH 330 of the sidelink resource 306a. As shown by the dashed arrow, SCI 910 indicates that the frequency subband 302 is used within the LBT gap duration 310b during time period 902b. S2 The LBT starting point 610a and the frequency sub-band 302 in S0 In some examples, the sidelink UE may be in the frequency subband 302 where the reserved LBT starting point 610 is located. S2 and 302 S0 The SCI 910 is sent in a different frequency sub-band 302. In some other examples, the sidelink UE may send the SCI 910 in the frequency sub-band 302 where the reserved LBT starting point 610 is located. S2 or frequency sub-band 302 S0 SCI 910 was sent in.

[0108] During time period 902b, the sidelink UE may be in frequency subband 302 starting at the earlier LBT starting point 610a. S2 If the frequency subband 302 S2 If the LBT in the frequency subband 302 is passed, the side link UE can S2 If the frequency subband 302 S2 If LBT fails in the sidelink UE, the sidelink UE can jump to the frequency subband 302 S0 , and in frequency sub-band 302 S0 If the frequency sub-band 302 S2 If the LBT in the frequency subband 302 is passed, the side link UE can S0 If the frequency subband 302 S0 If LBT fails in the frequency subband 302, the sidelink UE may avoid S0 Send it in.

[0109] As can be seen, the scheme 900 allows LBT-aware hopping to be performed within the same dwell time (eg, time period 902b). Reserving different LBT starting points 610 in different frequency subbands 302 within the dwell time increases the chances of a UE gaining access to the channel.

[0110] As shown in schemes 600, 700, 800 and / or 900 discussed above, providing multiple LBT starting points (e.g., LBT starting points 610a, 610b and 610c) and LBT starting point reservations can be beneficial for NR side links operating on unlicensed bands (e.g., 2.4 GHz bands). For example, the NR side link system is designed to utilize retransmissions to handle intra-system conflicts between side link UEs. NR side link conflicts may occur on relatively short NR side link subchannels or side link resources 306 durations (e.g., a duration of approximately 1 time slot or 1 ms). Therefore, the occurrence of side link conflicts may affect shorter durations. In this way, resource waste may be relatively small. However, when operating on unlicensed spectrum, channel access or LBT overhead may be important for shorter side link subchannel durations, and therefore, side link conflicts may seriously affect system performance and resource utilization, and become unbearable. Multiple LBT starting points and LBT starting point reservations can allow channel access to be prioritized between side link UEs. Prioritized access can reduce conflicts between sidelink UEs within the system.

[0111] In some aspects, the channel access priority of the sidelink UE can be time-dependent. For example, at a first moment, the sidelink UE can reserve a later LBT starting point (e.g., LBT starting point 610c) in a first LBT gap duration (e.g., LBT gap duration 310) for sidelink data transmission. At a second moment, the sidelink UE can reserve an earlier LBT starting point (e.g., LBT starting point 610b) in a second LBT gap duration for sidelink data transmission. At a third moment, the sidelink UE can reserve the earliest LBT starting point (e.g., LBT starting point 610a) in a third LBT gap duration for sidelink data transmission. Some example use cases may include V2X applications, in which a vehicle (e.g., a sidelink UE) can determine which LBT starting point to reserve in an LBT gap duration (e.g., LBT gap duration 310) based on the urgency of an upcoming data transmission. For example, in a V2X application, a vehicle can broadcast detected objects in a road system (via a side link) to notify other vehicles of road conditions and / or road hazards. If the vehicle detects a stationary object, since the location information of the stationary object may be relatively static, the vehicle may reserve a subsequent LBT starting point to send V2X data (e.g., sidelink data) to report the stationary object. If the vehicle detects a moving object, since the location information of the moving object may be valid for a short period of time, the vehicle may reserve an earlier LBT starting point to send V2X data (e.g., sidelink data) to report the moving object. If the vehicle determines that the moving object may pose a road hazard, and when the moving object approaches a location where the road hazard may occur, the vehicle may reserve the earliest LBT starting point to begin sending V2X data to report the moving object, because the location information of the moving object may be critical for other vehicles to take action. Thus, the prioritized channel access provided by multiple LBT starting points and / or LBT start reservations can better serve sidelink applications with transmission requirements that vary over time. It should be understood that the use cases described are exemplary and there are many other use cases for the present invention.

[0112] Fig.10 A sidelink frequency hopping scheme 1000 according to some aspects of the present disclosure is shown. The scheme 1000 may be employed by a UE (e.g., UE 115 and / or 215) in a network (e.g., network 100 and / or 200). Specifically, as shown in the scheme 1000, the UE may perform LBT in a shared channel (e.g., frequency band 301 and / or frequency subband 302) for sidelink transmissions. Fig.10 In the example, the x-axis represents time in some arbitrary units and the y-axis represents frequency in some arbitrary units. Figure 3 The side link frame structure 304 is described similar to that in FIG. 1 and for simplicity, the same side link frame structure 304 may be used. Figure 3 The same reference numerals are used in the drawings.

[0113] In the scheme 1000, the sidelink UE A (e.g., UE 115 and / or 215) can perform frequency hopping during COT 1002. In this regard, the sidelink UE can be configured with a frequency hopping pattern. In some examples, the sidelink UE can receive the frequency hopping pattern configuration from the serving BS (e.g., BS 105, 205, and / or 500) when it is within the coverage of the serving BS. Fig.10 In the example shown in FIG. 1 , the frequency hopping pattern of UE A may include frequency sub-bands 302 in sequence as shown by the dashed arrows. S2 ,302 S1 ,302 S2 and 302 S0 The frequency hopping pattern may be repeated, for example, the sidelink UE may select from frequency subband 302 S0 Jump back to frequency sub-band 302 S2 , and repeat Fig.10 The side link UE can use the same frequency hopping pattern as mentioned above. Figure 3 , Figure 4 , Figure 7 , Figure 8 and / or Fig. 9 A similar mechanism as discussed in schemes 300 , 600 , 700 , 800 , and / or 900 performs LBT to obtain COT 1002 .

[0114] COT 1002 includes a plurality of time slots or time periods 1004. Each time period 1004 may include sidelink resources 306. During time period 1004a, sidelink UE A is located in frequency subband 302. S2 The SCI 1010 is sent in the PSCCH 320 of the side link resource 306 of the side link resource 306. The SCI 1010 indicates the time period 1004b for the frequency subband 302 S1 (which is the next hop according to the frequency hopping pattern). Sidelink UE A can also reserve sidelink resources 306 at frequency subband 302. S2 PSSCH data 1030a is sent in a PSSCH (eg, PSSCH 330) in sidelink resources 306.

[0115] During time period 1004b, sidelink UE A is located in frequency subband 302 S1 The SCI 1012 is sent in the PSCCH 320 of the side link resource 306 of the side link resource 306. The SCI 1012 indicates the time period 1004b for the frequency subband 302 S1The sidelink UE A may also reserve a sidelink resource 306 at the frequency subband 302 based on the reservation indicated by the SCI 1010. S1 PSSCH data 1030a is sent in a PSSCH (eg, PSSCH 330) in sidelink resources 306.

[0116] During time period 1004c, sidelink UE A is located in frequency subband 302 S1 The SCI 1014 is sent in the PSCCH 320 of the side link resource 306 of the side link resource 306. The SCI 1014 indicates the time period 1004d for the frequency subband 302 S0 The sidelink UE A may also reserve sidelink resources 306 at the frequency subband 302 based on the reservation indicated by the SCI 1012. S1 PSSCH data 1030a is sent in a PSSCH (eg, PSSCH 330) in sidelink resources 306.

[0117] During time period 1004d, sidelink UE A may, based on the reservation indicated by SCI 1014, S0 At , SCI 1016 and PSSCH data 1030a are sent in PSCCH 320 and PSSCH (e.g., PSSCH 330) of side link resources 306, respectively.

[0118] As shown in scheme 1000, the other sidelink UE B may be configured to have a different frequency hopping pattern than the sidelink UE A, and to transmit PSSCH data 1030b during the same time period using a sidelink resource 306 in a different frequency subband 302 than the sidelink UE A. Similarly, the sidelink UE C may be configured to have a different frequency hopping pattern than the sidelink UE A and UE B, and to transmit PSSCH data 1030c during the same time period using a sidelink resource 306 in a different frequency subband 302 than the sidelink UE A or the sidelink UE C.

[0119] Frequency hopping may allow interference to be averaged over the duration of the COT 1002. Thus, in some instances, the COT may have a longer duration when frequency hopping is applied. For example, a COT obtained based on energy detection based LBT may have a duration of about 13 ms without frequency hopping, and may have a longer or extended duration of up to about 80 ms when frequency hopping is performed. Thus, a COT with frequency hopping may include several to tens of time slots (e.g., time period 1004). Frequency hopping channel access may also be referred to as digital modulation (DM) channel access.

[0120] The scheme 1000 with frequency hopping can be applicable to sidelink deployments on the 2.4 GHz unlicensed band, which has a channel access provision that utilizes frequency hopping. For example, a sidelink UE (e.g., sidelink UE A, sidelink UE B, and / or sidelink UE C) can be configured by a serving BS (e.g., BS 105, 205, and / or 500) to operate using a mode 2 RRA mechanism for sidelink communication. The sidelink UE can receive a sidelink resource pool configuration from the serving BS. The sidelink resource pool configuration can indicate a resource pool 1040 (e.g., resource pool 308) in the 2.4 GHz unlicensed band. The BS can also configure the sidelink UE with a frequency hopping mode to access the resource pool. The sidelink UE can perform channel access in the resource pool using the mechanism shown in the scheme 1000.

[0121] In some aspects, regulations may also limit transmissions from a node (e.g., UE 115, 215 and / or 400 and / or BS 105, 205 and / or 500) in a certain unlicensed band to have a maximum transmission time of approximately 5 ms and a minimum separation time of approximately 5 ms between transmissions.

[0122] In a sidelink system or network (e.g., network 100 and / or 200), CBR and / or CR may be used for congestion control and / or intra-system, intra-operator, and / or intra-technology collision avoidance. CBR is a metric indicating the number of subchannels (e.g., frequency subband 302) in a sidelink resource pool (e.g., resource pool 1040) for which a measured received signal strength indicator (RSSI) is greater than a preconfigured threshold divided by the total number of subchannels in the resource pool. The CBR metric may be calculated for a number of time intervals or subframes (e.g., time periods 702, 802, 902, and / or 1002). CBR may provide an estimate of the overall state of a channel. In some instances, a sidelink UE may calculate CBR by measuring RSSI in subchannels within a resource pool over a time interval comprising a plurality of subframes (e.g., approximately 100), counting the number of subchannels having RSSIs above a preconfigured threshold in the time interval (e.g., the number of subchannels), and dividing the subchannel count by the total number of subchannels in the resource pool. In some instances, for example, the sidelink UE may be configured by the serving BS with a CBR reporting configuration (eg, a CBR measurement time interval) to report the CBR to the BS.

[0123] In some aspects, as shown in scheme 1000, when the sidelink system utilizes frequency hopping, the sidelink UE (e.g., UE115, 215 and / or 400) can determine a CBR that is aware of frequency hopping. In this regard, the sidelink UE can be configured with a frequency hopping pattern, and the number of subchannels or frequency subbands in the frequency hopping pattern can be considered when calculating the CBR. In this regard, the sidelink UE can adjust the CBR by configuring a denominator for the CBR based on the total number of frequency subbands allocated and / or allowed by the frequency hopping pattern rather than the total number of frequency subbands in the resource pool. For example, a sidelink resource pool (e.g., sidelink resource pool 308 and / or 1040) can have 10 frequency subbands, and the sidelink UE can have been configured with a frequency hopping pattern including 5 frequency subbands. In order to calculate the CBR that is aware of frequency hopping, the sidelink UE can set the denominator of the CBR that is aware of frequency hopping to 5. In some instances, the sidelink UE may utilize one or more components (e.g., processor 402, sidelink communication module 408, transceiver 410, modem 412, and one or more antennas 416) to count the number of subchannels in the frequency hopping pattern having an RSSI above a preconfigured threshold over a time interval and calculate the CBR based on the count and the total number of subbands in the frequency hopping pattern.

[0124] CR is a metric that indicates the number of subchannels occupied by a sidelink UE for transmission (e.g., frequency subband 302) divided by the total number of subchannels in a resource pool. The CR metric may be calculated for a number of time intervals or subframes (e.g., time periods 702, 802, 902, and / or 1002). CR may provide an indication of channel utilization by the sidelink UE. In some instances, the sidelink UE may calculate the CR by counting the number of subchannels in a resource pool for which the sidelink UE has active transmissions (e.g., a subchannel count) over a time interval, and dividing the subchannel count by the total number of subchannels in the resource pool. In some instances, the sidelink UE may be configured, for example, by a serving BS to report the CR to the BS.

[0125] In some aspects, as shown in schemes 300, 600, 700, 800 and 900, when the sidelink system utilizes LBT, the sidelink UE (e.g., UE 115, 215 and / or 400) can determine a CR that is aware of LBT. In this regard, when calculating the CR, the sidelink UE can consider the number of subchannels or frequency subbands through which the sidelink UE passes through LBT. In this regard, the sidelink UE can adjust the CR by configuring the denominator of the CR based on the total number of frequency subbands in which the sidelink UE passes through LBT rather than the total number of frequency subbands in the resource pool. In other words, the CR that is aware of LBT can take into account the subchannels available to the sidelink UE. For example, the sidelink resource pool (e.g., sidelink resource pool 308 and / or 1040) can have 10 frequency subbands, and the sidelink UE can pass LBT in 5 frequency subbands. In order to calculate the CR that is aware of LBT, the sidelink UE can set the denominator of the CR that is aware of LBT to 5. The LBT-aware CR may provide an indication of intra-system or intra-operator or intra-technology blocking (e.g., blocked by another sidelink UE within the same sidelink system). In some examples, the sidelink UE may utilize one or more components (e.g., processor 402, sidelink communication module 408, transceiver 410, modem 412, and one or more antennas 416) to determine the number of subbands available to the sidelink UE (e.g., LBT passes) and the number of available subbands occupied by the sidelink UE, and calculate the CR based on the count and the total number of available frequency subbands.

[0126] In some aspects, when the sidelink system utilizes LBT as shown in schemes 300, 600, 700, 800, and 900 and frequency hopping as shown in scheme 1000, the sidelink UE (e.g., UE 115, 215, and / or 400) may determine a frequency hopping-aware, LBT-aware CR. In this regard, when calculating the CR, the sidelink UE may consider the number of subchannels or frequency subbands that the sidelink UE passes through the LBT and the number of subchannels in the frequency hopping pattern used by the UE. In this regard, the sidelink UE may adjust the CR by configuring a denominator of the CR based on the total number of frequency subbands in the frequency pattern in which the sidelink UE passes through the LBT. In other words, the frequency hopping-aware, LBT-aware CR may take into account the subchannels that are in the frequency hopping pattern and available to the sidelink UE. For example, a sidelink resource pool (e.g., sidelink resource pool 308 and / or 1040) may have 10 frequency subbands, and a sidelink UE may be configured with a frequency hopping pattern including 8 frequency subbands and may have passed LBT in 5 frequency subbands. To calculate a frequency hopping-aware, LBT-aware CR, the sidelink UE may set the denominator of the LBT-aware CR to 5. The frequency hopping-aware, LBT-aware CR may provide an indication of intra-system blocking (e.g., blocking by another sidelink UE within the same sidelink system) within the frequency subbands of the frequency hopping pattern. In some instances, the sidelink UE may utilize one or more components (e.g., processor 402, sidelink communication module 408, transceiver 410, modem 412, and one or more antennas 416) to determine the number of subbands available to the sidelink UE in the frequency hopping pattern (e.g., through LBT) and the number of available subbands occupied by the sidelink UE, and calculate the CR based on the count and the total number of available frequency subbands in the frequency hopping pattern.

[0127] In some aspects, a sidelink UE (e.g., UE 115, 215, and / or 400) may report a frequency hopping-aware CBR, an LBT-aware CR, and / or a frequency hopping-aware, LBT-aware CR to a serving BS (e.g., BS 105, 205, and / or 500). The serving BS may control sidelink intra-collisions, for example, by adjusting a resource pool configuration (e.g., the number of frequency subbands and / or the duration of the sidelink communication frame structure 304) and / or configuring one or more sidelink UEs with a modified frequency hopping pattern.

[0128] Fig.11100 . A flowchart of a sidelink communication method 1100 according to some aspects of the present disclosure is shown. Aspects of the method 1100 may be performed by a computing device (e.g., a processor, a processing circuit, and / or other suitable components) of a wireless communication device or other suitable means for performing these steps. For example, a wireless communication device (e.g., UE 115, UE 215, and / or UE 400) may utilize one or more components (e.g., processor 402, memory 404, sidelink communication module 408, transceiver 410, modem 412, and one or more antennas 416) to perform the steps of the method 1100. The method 1100 may be respectively implemented in accordance with the method for Figure 3 , Figure 6 , Figure 7 , Figure 8 , Fig. 9 and / or Fig.10 Similar mechanisms in the discussed schemes 300, 600, 700, 800, 900 and / or 1000. As shown, method 1100 includes a plurality of enumerated steps, but aspects of method 1100 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.

[0129] At block 1110, the first UE performs LBT in a shared radio frequency band (e.g., band 301) based on a first starting point among a plurality of starting points (e.g., LBT starting point 610) within a LBT gap duration (e.g., LBT gap duration 310). In some instances, the first UE may utilize one or more components (e.g., processor 402, sidelink communication module 408, transceiver 410, modem 412, and one or more antennas 416) to perform LBT by: measuring signal energy in the shared radio frequency band starting from the first starting point and within the duration of the CCA slot (e.g., ending at the next starting point); comparing the channel signal measurement result with a threshold; determining that LBT passes (e.g., the channel is available) when the channel signal measurement result is below the threshold; and determining that LBT fails (e.g., the channel is busy) when the channel signal measurement result is above the threshold.

[0130] At block 1120, the first UE sends a first sidelink communication to the second UE in the shared radio frequency band based on the LBT. The first sidelink communication includes a first SCI (e.g., SCI 710, 810, 812, 910, 1010, 1012, 1014, and / or 1016) and first sidelink data. In some instances, the first UE may utilize one or more components (e.g., processor 402, sidelink communication module 408, transceiver 410, modem 412, and one or more antennas 416) to send the first sidelink communication in the shared radio frequency band when the LBT performed at block 1110 is passed.

[0131] In some aspects, the first UE may select a first starting point from a plurality of starting points based on a priority of the first side link data for performing LBT at block 1110. In some instances, the first UE may utilize one or more components (e.g., processor 402, side link communication module 408, transceiver 410, modem 412, and one or more antennas 416) to select an earlier starting point from a plurality of starting points when the first side link data has a high priority; or, select a later starting point from a plurality of starting points when the first side link data has a low priority. In some aspects, the first UE may select several starting points from a plurality of starting points based on a priority of the first side link data for performing LBT at block 1110, as described above with reference to each of the foregoing. Figure 8 and / or Fig. 9 As discussed in scheme 800 and / or 900.

[0132] In some aspects, the first UE may also send a second SCI indicating a reservation for a first starting point for performing LBT at block 1110. In some instances, the first UE may utilize one or more components (e.g., processor 402, sidelink communication module 408, transceiver 410, modem 412, and one or more antennas 416) to send the second SCI.

[0133] In some aspects, the first UE may also receive a second SCI indicating a reservation for a second starting point among the plurality of starting points, and select, based on the second starting point, a first starting point for performing LBT at block 1110. In some instances, the first UE may utilize one or more components (e.g., the processor 402, the sidelink communication module 408, the transceiver 410, the modem 412, and the one or more antennas 416) to select the first starting point earlier than the second starting point when the first sidelink data has a higher priority, or select the first starting point later than the second starting point when the first sidelink data has a lower priority.

[0134] Other aspects of the present disclosure include a non-transitory computer-readable medium having program code recorded thereon. The non-transitory computer-readable medium includes: code for causing a first user equipment (UE) to perform a listen-before-talk (LBT) in a shared radio frequency band based on a first starting point among a plurality of starting points within a LBT gap duration. The non-transitory computer-readable medium also includes code for causing the first UE to send a first sidelink communication to a second UE in the shared radio frequency band based on the LBT, the first sidelink communication including first sidelink control information (SCI) and first sidelink data.

[0135] The non-transitory computer-readable medium may also include one or more of the following features. For example, the non-transitory computer-readable medium may include code for causing the first UE to select a first starting point from a plurality of starting points based on the priority of the first side link data. The non-transitory computer-readable medium may include code for causing the first UE to send a second SCI, the second SCI indicating a reservation for a first starting point for performing LBT. The reservation indicates a number of starting points among a plurality of starting points reserved for LBT, the number of starting points including the first starting point. The number of starting points among the plurality of starting points is based on the priority of the first side link data. The code for causing the first UE to perform LBT is configured to: perform the LBT in response to the failure of another LBT. The reservation indicates that the first starting point is associated with a first frequency subband in a shared radio frequency band, and the second starting point among the plurality of starting points is associated with a second frequency subband in the shared radio frequency band, the second frequency subband being different from the first frequency subband; and the code for causing the first UE to perform LBT is configured to: perform a first LBT in the first frequency subband based on the first starting point. The code for causing the first UE to perform LBT is configured to perform the second LBT in the second frequency subband based on the second starting point. The code for causing the first UE to perform LBT is configured to perform the first LBT in response to the failure of the second LBT. The code for causing the first UE to perform LBT is configured to perform LBT based on the first starting point being different from the second starting point indicated by the first reservation. The first starting point is after the second starting point based on at least one of the priority of the first side link data or the priority of the first reservation. The first starting point is before the second starting point based on at least one of the priority of the first side link data or the priority of the first reservation. The non-transitory computer-readable medium may include code for causing the first UE to send a third SCI indicating a second reservation for the first starting point based on the first side link data having a higher priority than the second side link data associated with the first reservation. The code for causing the first UE to send a first side link communication is configured to send a first SCI to the second UE based on a common SCI starting boundary between multiple side link UEs including the non-transitory computer-readable medium and the second UE; and send a fill signal before the first SCI. The code for causing the first UE to send a first sidelink communication is configured to: send a first SCI to the second UE that starts when the LBT passes. The code for causing the first UE to send a first sidelink communication is configured to: perform LBT in one or more frequency subbands within a shared radio frequency band; and the program code also includes code for causing the first UE to send a channel access occupancy (CR) report based on the number of frequency subbands in the one or more frequency subbands that pass the LBT.The code for causing the first UE to perform LBT is configured to: perform LBT in a first frequency subband among multiple frequency subbands in a shared radio frequency band, also based on a frequency hopping pattern; and the code for causing the first UE to send a first sidelink communication is configured to: send a first SCI in the first frequency subband, the first SCI indicating a reservation of a second frequency subband among multiple frequency subbands based on the frequency hopping pattern. The non-transitory computer-readable medium may include: a code for causing the first UE to send first sidelink data to the second UE in the first frequency subband during a first time period; and a code for causing the first UE to send second sidelink data to the second UE in the second frequency subband during a second time period after the reservation. The non-transitory computer-readable medium may include: a code for causing the first UE to send a channel busy rate (CBR) report based on the number of frequency subbands associated with the frequency hopping pattern in the multiple frequency subbands. The non-transitory computer-readable medium may include: a code for causing the first UE to perform LBT in each frequency subband associated with the frequency hopping pattern. Code for causing the first UE to send a channel access occupancy (CR) report based on the number of frequency subbands associated with the frequency hopping pattern through LBT.

[0136] Another aspect of the present disclosure includes an apparatus that includes means for performing a listen-before-talk (LBT) in a shared radio frequency band based on a first starting point of a plurality of starting points within a duration of a LBT gap. The apparatus also includes means for sending a first sidelink communication to a second UE in the shared radio frequency band based on the LBT, the first sidelink communication including first sidelink control information (SCI) and first sidelink data.

[0137] The apparatus may include one or more of the following features. For example, the apparatus may include a unit for selecting a first starting point from a plurality of starting points based on a priority of the first side link data. The apparatus includes a unit for sending a second SCI, the second SCI indicating a reservation for a first starting point for performing LBT. The reservation indicates a plurality of starting points reserved for LBT, the plurality of starting points including the first starting point. The number of starting points in the plurality of starting points is based on the priority of the first side link data. The unit for performing LBT is configured to: perform the LBT in response to a failure of another LBT. The reservation indicates that the first starting point is associated with a first frequency subband in a shared radio frequency band, and a second starting point in the plurality of starting points is associated with a second frequency subband in the shared radio frequency band, the second frequency subband being different from the first frequency subband; and the unit for performing LBT is configured to: perform a first LBT in the first frequency subband based on the first starting point. The unit for performing LBT is configured to: perform a second LBT in the second frequency subband based on the second starting point. The unit for performing the LBT is configured to perform the first LBT in response to the failure of the second LBT. The unit for performing the LBT is configured to perform the LBT based on the first starting point being different from the second starting point indicated by the first reservation. Based on at least one of the priority of the first side link data or the priority of the first reservation, the first starting point is after the second starting point. Based on at least one of the priority of the first side link data or the priority of the first reservation, the first starting point is before the second starting point. The device may include a unit for sending a third SCI indicating a second reservation for the first starting point based on the first side link data having a higher priority than the second side link data associated with the first reservation. The unit for sending the first side link communication is configured to send a first SCI to the second UE based on a common SCI start boundary between multiple side link UEs including the device and the second UE; and send a fill signal before the first SCI. The unit for sending the first side link communication is configured to send a first SCI to the second UE that starts when the LBT passes. The unit for performing LBT is configured to perform LBT in one or more frequency subbands within a shared radio frequency band; and the apparatus further includes a unit for sending a channel access occupancy (CR) report based on the number of frequency subbands in the one or more frequency subbands that pass LBT. The unit for performing LBT is configured to perform LBT in a first frequency subband among multiple frequency subbands in the shared radio frequency band based on a frequency hopping pattern; and the unit for sending a first side link communication is configured to send a first SCI in the first frequency subband, the first SCI indicating a reservation of a second frequency subband in the multiple frequency subbands based on the frequency hopping pattern.The apparatus may include: a unit for sending first sidelink data to a second UE in a first frequency subband during a first time period; and a unit for sending second sidelink data to the second UE in a second frequency subband during a second time period reserved after the first time period. The apparatus may include a unit for sending a channel busy rate (CBR) report based on the number of frequency subbands associated with a frequency hopping pattern in a plurality of frequency subbands. The apparatus may include a unit for performing LBT in each frequency subband associated with the frequency hopping pattern; and a unit for sending a channel access occupancy rate (CR) report based on the number of frequency subbands associated with the frequency hopping pattern through LBT.

[0138] Any of a variety of different technologies and methods may be used to represent information and signals. For example, data, instructions, commands, information, signals, bits, symbols, and chips 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.

[0139] 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 device, 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. A 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 structure).

[0140] The functions described herein can be implemented by hardware, software executed by a processor, firmware, or any combination thereof. If implemented by software executed by a processor, these functions can be stored on a computer-readable medium as one or more instructions or codes, or transmitted by a computer-readable medium. Other examples and implementations are within the scope of the present application and the appended claims. For example, due to the nature of software, the above-mentioned functions can be implemented using software executed by a processor, hardware, firmware, hard wiring, or any combination of these. The features that implement the functions can also be physically placed in various locations, including being distributed so that the parts that implement the functions at different physical locations. In addition, the "or" used in the list of items (for example, a list of items with phrases such as "at least one of them" or "one or more of them" in front) included in the claims indicates an inclusive list, so that, for example, a list of [at least one of A, B, or C] means A, or B, or C, or AB, or AC, or BC, or ABC (that is, A and B and C).

[0141] As will be presently apparent to those skilled in the art 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 thereof. In view of this, the scope of the present disclosure should not be limited to the scope of the specific aspects illustrated and described herein, as they are merely by way of some examples thereof, but should be fully commensurate with the scope of the appended claims and their functional equivalents.

Claims

1. A wireless communication method, comprising: performing, by a first user equipment (UE), LBT in a shared radio frequency band based on a first starting point of a plurality of starting points within a first listen-before-talk (LBT) gap duration; as well as The first UE sends a first sidelink communication to the second UE in the shared radio frequency band based on the LBT, the first sidelink communication comprising first sidelink control information (SCI) and first sidelink data, wherein the first SCI indicates a reservation for a first starting point among multiple starting points for performing LBT in the shared radio frequency band within a second LBT gap duration.

2. The method according to claim 1, further comprising: The first starting point is selected by the first UE from the multiple starting points within the second LBT gap duration based on the priority of the first sidelink data.

3. The method according to claim 1, wherein: The reservation indication is several starting points among the multiple starting points of the LBT reservation within the second LBT gap duration, and the several starting points include the first starting point within the second LBT gap duration.

4. The method according to claim 3, further comprising: sending, by the first UE, a second sidelink communication to the second UE in the shared radio frequency band based on the LBT performed during the second LBT gap duration, the second sidelink communication comprising a second SCI and second sidelink data; and The number of the starting points among the plurality of starting points is based on the priority of the second side link data.

5. The method according to claim 3, further comprising: performing, by the first UE, a second LBT based on a second starting point among the plurality of starting points within the second LBT gap duration, Wherein, performing the second LBT is in response to a failure of the first LBT within the second LBT gap duration.

6. The method according to claim 3, wherein: The reservation indicates that the first starting point is associated with a first frequency sub-band in the shared radio frequency band, and a second starting point of the plurality of starting points is associated with a second frequency sub-band in the shared radio frequency band, the second frequency sub-band being different from the first frequency sub-band; and further comprising: A first LBT is performed, by the first UE, in the first frequency subband in the second LBT gap duration based on the first starting point.

7. The method according to claim 6, further comprising: A second LBT is performed by the first UE in the second frequency subband based on the second starting point.

8. The method according to claim 7, wherein: The performing of the second LBT during the second LBT gap duration is in response to a failure of the first LBT during the second LBT gap duration.

9. The method according to claim 1, wherein: The sending the first side link communication comprises: The first UE sends the first SCI to the second UE based on a common SCI start boundary between a plurality of sidelink UEs including the first UE and the second UE; and A padding signal is sent by the first UE before the first SCI.

10. The method according to claim 1, wherein: The sending the first side link communication comprises: The first SCI is sent by the first UE to the second UE starting at the time when the LBT passes.

11. The method according to claim 1, wherein: The performing of the LBT comprises: performing, by the first UE, LBT in one or more frequency subbands within the shared radio frequency band; and The method further comprises: A channel access occupancy (CR) report is sent by the first UE based on the number of frequency subbands in the one or more frequency subbands with LBT passed.

12. A method of wireless communication, comprising: performing, by a first user equipment (UE), a listen-before-talk (LBT) in a shared radio frequency band based on a first starting point of a plurality of starting points within a duration of a LBT gap; Sending, by the first UE, a first sidelink communication to a second UE in the shared radio frequency band based on the LBT, the first sidelink communication comprising first sidelink control information (SCI) and first sidelink data; as well as receiving, by the first UE, a second SCI indicating a first reservation for a second starting point among the plurality of starting points; Wherein, the performing of the LBT is based on the first starting point being different from the second starting point indicated by the first reservation.

13. The method according to claim 12, wherein: The first starting point is subsequent to the second starting point based on at least one of a priority of the first sidelink data or a priority of the first reservation.

14. The method according to claim 12, wherein: The first starting point is before the second starting point based on at least one of a priority of the first sidelink data or a priority of the first reservation.

15. The method according to claim 14, further comprising: After passing the LBT, a third SCI indicating a second reservation for the first starting point is sent by the first UE based on the first sidelink data having a higher priority than second sidelink data associated with the first reservation.

16. A method of wireless communication, comprising: performing, by a first user equipment (UE), LBT in a shared radio frequency band based on a first starting point of a plurality of starting points within a first listen-before-talk (LBT) gap duration; as well as sending, by the first UE based on the LBT, a first sidelink communication to a second UE in the shared radio frequency band, wherein the first sidelink communication includes first sidelink control information (SCI) and first sidelink data, Wherein, performing the LBT comprises: performing, by the first UE, the LBT in a first frequency subband of a plurality of frequency subbands in the shared radio frequency band also based on a frequency hopping pattern; and The sending the first side link communication comprises: The first SCI is sent by the first UE in the first frequency subband, the first SCI indicating a reservation of a second frequency subband among the plurality of frequency subbands based on the frequency hopping pattern.

17. The method according to claim 16, further comprising: sending, by the first UE, the first sidelink data to the second UE in the first frequency sub-band during a first time period; as well as Second sidelink data is sent, by the first UE to the second UE in the second frequency subband during a second time period after the first time period based on the reservation.

18. The method according to claim 16, further comprising: A channel busy rate (CBR) report is sent by the first UE based on a number of frequency subbands associated with the frequency hopping pattern in the plurality of frequency subbands.

19. The method according to claim 16, further comprising: performing, by the first UE, LBT in each frequency subband associated with the frequency hopping pattern; as well as A channel access occupancy (CR) report is sent by the first UE based on a number of frequency subbands associated with the frequency hopping pattern having LBT passed.

20. An apparatus comprising: a processor configured to: perform LBT in a shared radio frequency band based on a first starting point of a plurality of starting points within a first listen-before-talk (LBT) gap duration; as well as A transceiver that communicates with the processor, the processor being configured to: based on the LBT, send a first side link communication to a second user equipment (UE) in the shared radio frequency band, the first side link communication comprising first side link control information (SCI) and first side link data, wherein the first SCI indicates a reservation for a first starting point among multiple starting points for performing LBT in the shared radio frequency band within a second LBT gap duration.

21. The device according to claim 20, wherein: The processor is further configured to: The first starting point is selected from the multiple starting points within the second LBT gap duration based on the priority of the first side link data.

22. The device according to claim 20, wherein: The reservation indication is several starting points among the multiple starting points of the LBT reservation within the second LBT gap duration, and the several starting points include the first starting point within the second LBT gap duration.

23. The device according to claim 22, wherein: The processor is further configured to: Based on the LBT performed during the second LBT gap duration, sending a second sidelink communication to the second UE in the shared radio frequency band, the second sidelink communication comprising a second SCI and second sidelink data; and The number of the starting points among the plurality of starting points is based on the priority of the second side link data.

24. The apparatus of claim 22, wherein: The processor is further configured to: performing a second LBT based on a second starting point among the plurality of starting points within the second LBT gap duration; and The processor configured to perform the second LBT is configured to: The second LBT is performed in response to a failure of the first LBT within the second LBT gap duration.

25. The apparatus of claim 22, wherein: The reservation indicates that the first starting point is associated with a first frequency sub-band in the shared radio frequency band, and a second starting point of the plurality of starting points is associated with a second frequency sub-band in the shared radio frequency band, the second frequency sub-band being different from the first frequency sub-band; and Wherein, the processor is further configured to: A first LBT is performed in the first frequency sub-band based on the first starting point within the second LBT gap duration.

26. The device according to claim 25, wherein The processor is further configured to: A second LBT is performed in the second frequency sub-band based on the second starting point.

27. The device according to claim 26, wherein: The processor configured to perform the second LBT during the second LBT gap duration is configured to: The second LBT is performed during the second LBT gap duration in response to a failure of the first LBT during the second LBT gap duration.

28. The device according to claim 20, wherein: The transceiver configured to transmit the first side link communication is configured to: sending the first SCI to the second UE based on a common SCI start boundary among a plurality of sidelink UEs including the apparatus and the second UE; and A filling signal is sent before the first SCI.

29. The device according to claim 20, wherein: The transceiver configured to transmit the first side link communication is configured to: The first SCI is sent to the second UE starting at the time when the LBT passes.

30. The apparatus of claim 20, wherein: The processor configured to perform the LBT is configured to: performing LBT in one or more frequency sub-bands within the shared radio frequency band; and The transceiver is further configured to: A channel access occupancy (CR) report is sent based on the number of frequency subbands in the one or more frequency subbands having LBT passed.

31. An apparatus comprising: a processor configured to: perform LBT in a shared radio frequency band based on a first starting point of a plurality of starting points within a first listen-before-talk (LBT) gap duration; as well as a transceiver in communication with the processor, the processor being configured to: send, based on the LBT, a first sidelink communication to a second user equipment (UE) in the shared radio frequency band, the first sidelink communication comprising first sidelink control information (SCI) and first sidelink data, the transceiver being further configured to: receiving a second SCI indicating a first reservation for a second starting point among the plurality of starting points; and the processor configured to perform the LBT is configured to: The LBT is performed based on the first starting point being different from the second starting point indicated by the first reservation.

32. The device according to claim 31, wherein The first starting point is subsequent to the second starting point based on at least one of a priority of the first sidelink data or a priority of the first reservation.

33. The device according to claim 31, wherein The first starting point is before the second starting point based on at least one of a priority of the first sidelink data or a priority of the first reservation.

34. The device according to claim 33, wherein The transceiver is further configured to: After passing the LBT, based on the first side link data having a higher priority than the second side link data associated with the first reservation, a third SCI indicating a second reservation for the first starting point is sent.

35. An apparatus comprising: a processor configured to: perform LBT in a shared radio frequency band based on a first starting point of a plurality of starting points within a first listen-before-talk (LBT) gap duration; as well as a transceiver in communication with the processor, the processor being configured to: transmit, based on the LBT, a first sidelink communication to a second user equipment (UE) in the shared radio frequency band, the first sidelink communication comprising first sidelink control information (SCI) and first sidelink data; Wherein, the processor configured to perform the LBT is configured to: performing the LBT in a first frequency sub-band of a plurality of frequency sub-bands in the shared radio frequency band, also based on a frequency hopping pattern; and The transceiver configured to transmit the first side link communication is configured to: The first SCI is transmitted in the first frequency sub-band, the first SCI indicating a reservation of a second frequency sub-band among the plurality of frequency sub-bands based on the frequency hopping pattern.

36. The device according to claim 35, wherein The transceiver is further configured to: sending the first sidelink data to the second UE in the first frequency sub-band during a first time period; and Based on the reservation, second sidelink data is sent to the second UE in the second frequency sub-band during a second time period after the first time period.

37. The device according to claim 35, wherein: The transceiver is further configured to: A channel busy rate (CBR) report is sent based on a number of frequency subbands associated with the frequency hopping pattern in the plurality of frequency subbands.

38. The apparatus of claim 35, wherein: The processor is further configured to: performing LBT in each frequency sub-band associated with the frequency hopping pattern; and A channel access occupancy (CR) report is sent based on the number of frequency subbands associated with the frequency hopping pattern that have LBT passed.

39. A non-transitory computer readable medium having program code recorded thereon, the program code comprising: code for causing a first user equipment (UE) to perform a listen-before-talk (LBT) in a shared radio frequency band based on a first starting point of a plurality of starting points within a duration of a LBT gap; as well as Code for causing the first UE to send a first sidelink communication to a second UE in the shared radio frequency band based on the LBT, the first sidelink communication comprising first sidelink control information (SCI) and first sidelink data, wherein the first SCI indicates a reservation for a first starting point among multiple starting points for performing LBT in the shared radio frequency band within a second LBT gap duration.

40. An apparatus comprising: means for performing a listen-before-talk (LBT) in a shared radio frequency band based on a first starting point of a plurality of starting points within a duration of a LBT gap; as well as A unit for sending a first sidelink communication to a second UE in the shared radio frequency band based on the LBT, the first sidelink communication comprising first sidelink control information (SCI) and first sidelink data, wherein the first SCI indicates a reservation of a first starting point among multiple starting points for performing LBT in the shared radio frequency band within a second LBT gap duration.

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