WO2021217484A1

WO2021217484A1 - Sidelink slot structure for sidelink communication in a wireless communications network

Info

Publication number: WO2021217484A1
Application number: PCT/CN2020/087737
Authority: WO
Inventors: Changlong Xu; Jing Sun; Xiaoxia Zhang; Tao Luo; Juan Montojo
Original assignee: Qualcomm Incorporated
Priority date: 2020-04-29
Filing date: 2020-04-29
Publication date: 2021-11-04

Abstract

Wireless communications systems and methods related to use of cyclic prefix (CP) extensions among sidelink user equipment devices (UEs) are provided. A UE may determine a cyclic prefix (CP) extension length to provide an automatic gain control (AGC) duration and a gap duration for a sidelink transmission. The UE may apply a CP extension having the CP extension length to the sidelink transmission and transmit the sidelink transmission with the CP extension.

Description

SIDELINK SLOT STRUCTURE FOR SIDELINK COMMUNICATION IN A WIRELESS COMMUNICATIONS NETWORK

TECHNICAL FIELD

This application relates to wireless communication systems, and more particularly to cyclic prefix (CP) extensions associated with an automatic gain control (AGC) duration and a gap duration for sidelink communications.

INTRODUCTION

Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power) . A wireless multiple-access communications system may include a number of base stations (BSs) , each simultaneously supporting communications for multiple communication devices, which may be otherwise known as user equipment (UE) .

To meet the growing demands for expanded mobile broadband connectivity, wireless communication technologies are advancing from the long term evolution (LTE) technology to a next generation new radio (NR) technology, which may be referred to as 5 ^th Generation (5G) . For example, NR is designed to provide a lower latency, a higher bandwidth or a higher throughput, and a higher reliability than LTE. NR is designed to operate over a wide array of spectrum bands, for example, from low-frequency bands below about 1 gigahertz (GHz) and mid-frequency bands from about 1 GHz to about 6 GHz, to high-frequency bands such as millimeter wave (mmWave) bands. NR is also designed to operate across different spectrum types, from licensed spectrum to unlicensed and shared spectrum. Spectrum sharing enables operators to opportunistically aggregate spectrums to dynamically support high-bandwidth services. Spectrum sharing can extend the benefit of NR technologies to operating entities that may not have access to a licensed spectrum.

In a wireless communication network, a BS may communicate with a UE in an uplink direction and a downlink direction. Sidelink was introduced in LTE to allow a UE to send data to another UE without tunneling through the BS and/or an associated core network. The LTE sidelink technology had been extended to provision for device-to-device (D2D) communications, vehicle-to-everything (V2X) communications, and/or cellular vehicle-to-everything (C-V2X) communications. Similarly, NR may be extended to support sidelink communications, D2D communications, V2X communications, and/or C-V2X over licensed bands and/or unlicensed bands.

BRIEF SUMMARY OF SOME EXAMPLES

The following summarizes some aspects of the present disclosure to provide a basic understanding of the discussed technology. This summary is not an extensive overview of all contemplated features of the disclosure and is intended neither to identify key or critical elements of all aspects of the disclosure nor to delineate the scope of any or all aspects of the disclosure. Its sole purpose is to present some concepts of one or more aspects of the disclosure in summary form as a prelude to the more detailed description that is presented later.

For example, in an aspect of the disclosure, a method of wireless communication performed by a sidelink user equipment (UE) includes: determining a cyclic prefix (CP) extension length to provide an automatic gain control (AGC) duration and a gap duration for a sidelink transmission; applying a CP extension having the CP extension length to the sidelink transmission; and transmitting the sidelink transmission with the CP extension.

In an additional aspect of the disclosure, a user equipment (UE) includes a processor and a transceiver. The processor is configured to: determine a cyclic prefix (CP) extension length to provide an automatic gain control (AGC) duration and a gap duration for a sidelink transmission; and apply a CP extension having the CP extension length to the sidelink transmission; and the transceiver is configured to transmit the sidelink transmission with the CP extension.

In an additional aspect of the disclosure, a non-transitory computer-readable medium having program code recorded thereon, the program code including: code for causing a sidelink user equipment (UE) to determine a cyclic prefix (CP) extension length to provide an automatic gain control (AGC) duration and a gap duration for a sidelink transmission; code for causing the sidelink UE to apply a CP extension having the CP extension length to the sidelink transmission; and code for causing the sidelink UE to transmit the sidelink transmission with the CP extension.

In an additional aspect of the disclosure, a first user equipment (UE) includes means for determining a cyclic prefix (CP) extension length to provide an automatic gain control (AGC) duration and a gap duration for a sidelink transmission; means for applying a CP extension having the CP extension length to the sidelink transmission; and means for transmitting the sidelink transmission with the CP extension.

Other aspects, features, and embodiments of the present invention will become apparent to those of ordinary skill in the art, upon reviewing the following description of specific, exemplary embodiments of the present invention in conjunction with the accompanying figures. While features of the present invention may be discussed relative to certain embodiments and figures below, all embodiments of the present invention can include one or more of the advantageous features discussed herein. In other words, while one or more embodiments may be discussed as having certain advantageous features, one or more of such features may also be used in accordance with the various embodiments of the invention discussed herein. In similar fashion, while exemplary embodiments may be discussed below as device, system, or method embodiments it should be understood that such exemplary embodiments can be implemented in various devices, systems, and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a wireless communication network according to one or more aspects of the present disclosure.

FIG. 2 is a timing diagram illustrating a transmission frame structure according to one or more aspects of the present disclosure.

FIG. 3 illustrates a sidelink slot structure scheme for physical sidelink control channel (PSCCH) /physical sidelink shared channel (PSSCH) transmission according to one or more aspects of the present disclosure.

FIG. 4 illustrates transmission of PSCCH/PSSCH in two adjacent slots using the sidelink slot structure scheme according to one or more aspects of the present disclosure.

FIG. 5 illustrates a sidelink slot structure scheme for physical sidelink feedback channel (PSFCH) transmission according to one or more aspects of the present disclosure.

FIG. 6 illustrates transmission of PSCCH/PSSCH and PSFCH in two adjacent slots using the sidelink slot structure scheme according to one or more aspects of the present disclosure.

FIG. 7 illustrates a sidelink slot structure scheme for PSCCH/PSSCH transmission according to one or more aspects of the present disclosure.

FIG. 8 illustrates a sidelink slot structure scheme for PSFCH transmission according to one or more aspects of the present disclosure.

FIG. 9 illustrates a sidelink slot structure scheme for PSCCH/PSSCH transmission according to one or more aspects of the present disclosure.

FIG. 10 is a block diagram of an example user equipment (UE) according to one or more aspects of the present disclosure.

FIG. 11 is a block diagram of an example base station (BS) according to one or more aspects of the present disclosure.

FIG. 12 illustrates a flow diagram of a communication method for transmitting a sidelink communication associated with a CP extension in accordance with one or more aspects of the present disclosure.

DETAILED DESCRIPTION

The detailed description set forth below, in connection with the appended drawings, is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

This disclosure relates generally to wireless communications systems, also referred to as wireless communications networks. In various embodiments, the techniques and apparatus may 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 System for Mobile Communications (GSM) networks, 5 ^th Generation (5G) or new radio (NR) networks, as well as other communications networks. As described herein, the terms “networks” and “systems” may be used interchangeably.

An OFDMA network may implement a radio technology such as evolved UTRA (E-UTRA) , Institute of Electrical and Electronics Engineers (IEEE) 802.11, IEEE 802.16, IEEE 802.20, flash-OFDM and the like. UTRA, E-UTRA, and GSM are part of universal mobile telecommunication system (UMTS) . In particular, long term evolution (LTE) is a release of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS and LTE are described in documents provided from 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 are being developed. For example, the 3rd Generation Partnership Project (3GPP) is a collaboration between groups of telecommunications associations that aims to define a globally applicable third generation (3G) mobile phone specification. 3GPP long term evolution (LTE) is a 3GPP project which was aimed at improving the UMTS mobile phone standard. The 3GPP may define specifications for the next generation of mobile networks, mobile systems, and mobile devices. The present disclosure is concerned with the evolution of wireless technologies from LTE, 4G, 5G, NR, and beyond with shared access to wireless spectrum between networks using a collection of new and different radio access technologies or radio air interfaces.

In particular, 5G networks contemplate diverse deployments, diverse spectrum, and diverse services and devices that may be implemented using an OFDM-based unified, air interface. In order to achieve these goals, further enhancements to LTE and LTE-A are considered in addition to development of the new radio technology for 5G NR networks. The 5G NR will be capable of scaling to provide coverage (1) to a massive Internet of things (IoTs) with a ULtra-high density (e.g., ～1M nodes/km ²) , ultra-low complexity (e.g., ～10s of bits/sec) , ultra-low energy (e.g., ～10+ years of battery life) , and deep coverage with the capability to reach challenging locations; (2) including mission-critical control with strong security to safeguard sensitive personal, financial, or classified information, ultra-high reliability (e.g., ～99.9999%reliability) , ultra-low latency (e.g., ～ 1 millisecond (ms) ) , and users with wide ranges of mobility or lack thereof; and (3) with enhanced mobile broadband including extreme high capacity (e.g., ～ 10 Tbps/km ²) , extreme data rates (e.g., multi-Gbps rate, 100+ Mbps user experienced rates) , and deep awareness with advanced discovery and optimizations.

The 5G NR may be implemented to use optimized OFDM-based waveforms with scalable numerology and transmission time interval (TTI) ; having a common, flexible framework to efficiently multiplex services and features with a dynamic, low-latency time division duplex (TDD) /frequency division duplex (FDD) design; and with advanced wireless technologies, such as massive multiple input, multiple output (MIMO) , robust millimeter wave (mmWave) transmissions, advanced channel coding, and device-centric mobility. Scalability of the numerology in 5G NR, with scaling of subcarrier spacing, may efficiently address operating diverse services across diverse spectrum and diverse deployments. For example, in various outdoor and macro coverage deployments of less than 3GHz FDD/TDD implementations, subcarrier spacing may occur with 15 kilohertz (kHz) , for example over 5, 10, 20 MHz, and the like bandwidth (BW) . For other various outdoor and small cell coverage deployments of TDD greater than 3 GHz, subcarrier spacing may occur with 30 kHz over 80/100 MHz BW. For other various indoor wideband implementations, using a TDD over the unlicensed portion of the 5 GHz band, the subcarrier spacing may occur with 60 kHz over a 160 MHz BW. Finally, for various deployments transmitting with mmWave components at a TDD of 28 GHz, subcarrier spacing may occur with 120 kHz over a 500 MHz BW.

The scalable numerology of the 5G NR facilitates scalable TTI for diverse latency and quality of service (QoS) requirements. For example, shorter TTI may be used for low latency and high reliability, while longer TTI may be used for higher spectral efficiency. The efficient multiplexing of long and short TTIs to allow transmissions to start on symbol boundaries. 5G NR also contemplates a self-contained integrated subframe design with UL/downlink scheduling information, data, and acknowledgement in the same subframe. The self-contained integrated subframe supports communications in unlicensed or contention-based shared spectrum, adaptive UL/downlink that may be flexibly configured on a per-cell basis to dynamically switch between UL and downlink to meet the current traffic needs.

Various other aspects and features of the disclosure are further described below. It should be apparent that the teachings herein may be embodied in a wide variety of forms and that any specific structure, function, or both being disclosed herein is merely representative and not limiting. Based on the teachings herein one of an ordinary level of skill in the art should appreciate that an aspect disclosed herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, such an apparatus may be implemented or such a method may be practiced using other structure, functionality, or structure and functionality in addition to or other than one or more of the aspects set forth herein. For example, a method may be implemented as part of a system, device, apparatus, and/or as instructions stored on a computer readable medium for execution on a processor or computer. Furthermore, an aspect may comprise at least one element of a claim.

NR technologies had been extended to operate over an unlicensed spectrum. The deployment of NR technologies over an unlicensed spectrum is referred to as NR-U. NR-U is targeted for operations over the 5 gigahertz (GHz) and 6 GHz bands, where there are well-defined channel access rules for sharing among operators of the same radio access technology (RAT) and/or of different RATs. When a BS operates over an unlicensed spectrum, the BS does not have ownership of the spectrum or control over the spectrum. Thus, the BS contends for channel access in the spectrum, for example, via clear channel assessment (CCA) and/or listen-before-talk (LBT) procedures.

The provisioning of sidelink services, such as device-to-device (D2D) , vehicle-to-vehicle (V2V) , vehicle-to-everything (V2X) , and/or cellular vehicle-to-everything (C-V2X) communications, over dedicated spectrum or licensed spectrum are relatively straight-forward as channel access in the dedicated spectrum or licensed spectrum is guaranteed. NR-U can bring a benefit for sidelink services, for example, by offloading sidelink traffic to the unlicensed spectrum at no cost. However, channel access in a shared spectrum or an unlicensed spectrum is not guaranteed. Thus, to provision for sidelink services over a shared spectrum or unlicensed spectrum, sidelink user equipment devices (UEs) contend for channel access in the spectrum, for example, via CCA and/or LBT procedures.

Sidelink UEs may receive or transmit V2X sidelink communications using a plurality of sidelink slot structure configurations. The plurality of sidelink slot structure configurations may include a first sidelink slot structure configuration for physical sidelink control channel (PSCCH) /physical sidelink shared channel (PSSCH) transmission and a second sidelink slot structure configuration for physical sidelink feedback channel (PSFCH) communication (e.g., receiving PSFCH or transmitting PSFCH) . The first sidelink slot structure configuration may include fourteen symbols (e.g., OFDM symbols) in a slot, with thirteen symbols overall for PSCCH/PSSCH and the last symbol in the slot left as a transmission gap (with no transmission) . The first symbol of the thirteen symbols may be a repetition of the second symbol in the slot, where the first symbol is at the beginning of the slot and immediately precedes the second symbol. A first symbol immediately precedes a second symbol if the second symbol follows the first symbol and no other symbols are between the first and second symbols. Additionally, the first sidelink slot structure configuration may be devoid of PSFCH. In other words, the beginning symbol of the slot may be followed by twelve consecutive symbols for PSCCH/PSSCH, which is followed by a gap duration in the last symbol of the slot. In the first sidelink slot structure configuration, the first symbol is used for automatic gain control (AGC) and the last symbol is used for a gap. AGC detects the energy of a signal in the channel and applies a hardware gain to maximize the signal amplitude to the dynamic range (for the ADC) at the receiver. The receiver determines a gain for a received signal, and an AGC duration allows time for the receiver to determine the gain and apply the gain (e.g., hardware gain component) such that when the receiver receives the data (e.g., in the next symbol) , the gain has already been adjusted. The overhead for the first sidelink slot structure configuration is 2/14 (based on the repetition and gap symbols) .

The second sidelink slot structure configuration may include fourteen symbols (e.g., OFDM symbols) in a slot, with ten symbols overall for PSCCH/PSSCH transmission. In the second sidelink slot structure configuration, the first symbol of the slot may be a repetition of the second symbol in the slot, where the first symbol is at the beginning of the slot and immediately precedes the second symbol. The first symbol is followed by nine consecutive symbols for PSCCH/PSSCH, which is followed by a first gap duration. The first gap duration is followed by a second repetition symbol that is a repetition of the PSFCH symbol, where the second repetition symbol immediately precedes the PSFCH symbol. A second gap duration follows the PSFCH symbol and is the last symbol of the slot. The overhead for the first sidelink slot structure configuration is 4/14 (based on the two repetition symbols and two gap symbols) .

It may be desirable to reduce the overhead when communicating sidelink communications. For example, if the first and second sidelink slot structure configurations are used for a subcarrier spacing (SCS) of about 60 kHz, a symbol duration in the configurations may be about 16.67 microseconds (μs) . The SCS may be inversely related to the symbol duration. For example, the larger the SCS, the shorter the symbol duration. In contrast, the smaller the SCS, the longer the symbol duration. For SCS of about 60 kHz, one symbol may be used for the AGC, and one symbol may be used for the gap. For SCS that is smaller than 60 kHz (e.g., about 15 kHz or about 30 kHz) , it may be unnecessary for the AGC duration or the gap duration to occupy a whole symbol. For example, each of the AGC duration and the gap duration may occupy less than a whole symbol.

The present disclosure provides techniques for controlling one or more AGC durations and/or one or more gap durations in a slot-based transmission. One way to provide an AGC duration and a gap duration is to apply a CP extension to a transmission, where the AGC duration uses the CP extension (rather than a symbol repetition) and the gap duration is created by applying the CP extension to the transmission. The CP extension may be based on a SCS. In some aspects, a sidelink UE may determine a CP extension length to provide the AGC duration and the gap duration for a sidelink transmission and apply a CP extension having the CP extension length to the sidelink transmission. The sidelink UE may transmit the sidelink transmission with the CP extension. Mechanisms for providing the AGC duration and the gap duration using a CP extension are described in greater detail herein.

Aspects of the present disclosure can provide several benefits. For example, applying the CP extension having the CP extension length to the UE’s sidelink transmission may reduce resource overhead by enabling more symbols in a slot to be used for PSCCH, PSSCH, and/or PSFCH communications. By shortening the AGC duration and the gap duration such that each is shorter than a symbol duration, more resources for transmission of PSCCH/PSSCH and/or communication of PSFCH may be created in a single slot. Thus, the disclosed examples may reduce resource overhead and enable sidelink communications to consume less time (e.g., by being transmitted in fewer slots) .

FIG. 1 illustrates a wireless communication network 100 according to one or more aspects of the present disclosure. The network 100 may be a 5G network. The network 100 includes a number of base stations (BSs) 105 (individually labeled as 105a, 105b, 105c, 105d, 105e, and 105f) and other network entities. A BS 105 may be a station that communicates with UEs 115 and may also be referred to as an evolved node B (eNB) , a next generation eNB (gNB) , an access point, and the like. Each BS 105 may provide communication coverage for a particular geographic area. In 3GPP, the term “cell” can refer to this particular geographic coverage area of a BS 105 and/or a BS subsystem serving the coverage area, depending on the context in which the term is used.

A BS 105 may provide communication coverage for a macro cell or a small cell, such as a pico cell or a femto cell, and/or other types of cell. A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions with the network provider. A small cell, such as a pico cell, would generally cover a relatively smaller geographic area and may allow unrestricted access by UEs with service subscriptions with the network provider. A small cell, such as a femto cell, would also generally cover a relatively small geographic area (e.g., a home) and, in addition to unrestricted access, may also provide restricted access by UEs having an association with the femto cell (e.g., UEs in a closed subscriber group (CSG) , UEs for users in the home, and the like) . A BS for a macro cell may be referred to as a macro BS. A BS for a small cell may be referred to as a small cell BS, a pico BS, a femto BS or a home BS. In the example shown in FIG. 1, the

BSs

105d and 105e may be regular macro BSs, while the BSs 105a-105c may be macro BSs enabled with one of three dimension (3D) , full dimension (FD) , or massive MIMO. The BSs 105a-105c may take advantage of their higher dimension MIMO capabilities to exploit 3D beamforming in both elevation and azimuth beamforming to increase coverage and capacity. The BS 105f may be a small cell BS which may be a home node or portable access point. A BS 105 may support one or multiple (e.g., two, three, four, and the like) cells.

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.

The UEs 115 are dispersed throughout the wireless network 100, and each UE 115 may be stationary or mobile. A UE 115 may also be referred to as a terminal, a mobile station, a subscriber unit, a station, or the like. A UE 115 may be a cellular phone, a personal digital assistant (PDA) , a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless phone, a wireless local loop (WLL) station, or the like. In one aspect, a UE 115 may be a device that includes a Universal Integrated Circuit Card (UICC) . In another aspect, a UE may be a device that does not include a UICC. In some aspects, the UEs 115 that do not include UICCs may also be referred to as IoT devices or internet of everything (IoE) devices. The UEs 115a-115d are examples of mobile smart phone-type devices accessing network 100. A UE 115 may also be a machine specifically configured for connected communication, including machine type communication (MTC) , enhanced MTC (eMTC) , narrowband IoT (NB-IoT) and the like. The UEs 115e-115h are examples of various machines configured for communication that access the network 100. The UEs 115i-115k are examples of vehicles equipped with wireless communication devices configured for communication that access the network 100. A UE 115 may be able to communicate with any type of the BSs, whether macro BS, small cell, or the like. In FIG. 1, a lightning bolt (e.g., communication links) indicates wireless transmissions between a UE 115 and a serving BS 105, which is a BS designated to serve the UE 115 on the downlink (DL) and/or uplink (UL) , desired transmission between BSs 105, backhaul transmissions between BSs, or sidelink transmissions between UEs 115.

In operation, the BSs 105a-105c may serve the

UEs

115a and 115b using 3D beamforming and coordinated spatial techniques, such as coordinated multipoint (CoMP) or multi-connectivity. The macro BS 105d may perform backhaul communications with the BSs 105a-105c, as well as small cell, the BS 105f. The macro BS 105d may also transmits multicast services which are subscribed to and received by the

UEs

115c and 115d. Such multicast services may include mobile television or stream video, or may include other services for providing community information, such as weather emergencies or alerts, such as Amber alerts or gray alerts.

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 an example of a gNB or an access node controller (ANC) ) may interface with the core network through backhaul links (e.g., NG-C, NG-U, etc. ) and may perform radio configuration and scheduling for communication with the UEs 115. In various examples, the BSs 105 may communicate, either directly or indirectly (e.g., through core network) , with each other over backhaul links (e.g., X1, X2, etc. ) , which may be wired or wireless communication links.

The network 100 may also support mission critical communications with ultra-reliable and redundant links for mission critical devices, such as the UE 115e, which may be a drone. Redundant communication links with the UE 115e may include links from the

macro BSs

105d and 105e, as well as links from the small cell BS 105f. Other machine type devices, such as the UE 115f (e.g., a thermometer) , the UE 115g (e.g., smart meter) , and UE 115h (e.g., wearable device) may communicate through the network 100 either directly with BSs, such as the small cell BS 105f, and the macro BS 105e, or in multi-step-size configurations by communicating with another user device which relays its information to the network, such as the UE 115f communicating temperature measurement information to the smart meter, the UE 115g, which is then reported to the network through the small cell BS 105f. The network 100 may also provide additional network efficiency through dynamic, low-latency TDD/FDD communications, such asV2V, V2X, C-V2X communications between a

UE

115i, 115j, or 115k and other UEs 115, and/or vehicle-to-infrastructure (V2I) communications between a

UE

115i, 115j, or 115k and a BS 105.

In some implementations, the network 100 utilizes OFDM-based waveforms for communications. An OFDM-based system may partition the system BW into multiple (K) orthogonal subcarriers, which are also commonly referred to as subcarriers, tones, bins, or the like. Each subcarrier may be modulated with data. In some instances, the subcarrier spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may be dependent on the system BW. The system BW may also be partitioned into subbands. In other instances, the subcarrier spacing and/or the duration of TTIs may be scalable.

In some aspects, the BSs 105 can assign or schedule transmission resources (e.g., in the form of time-frequency resource blocks (RB) ) for downlink (DL) and uplink (UL) transmissions in the network 100. DL refers to the transmission direction from a BS 105 to a UE 115, whereas UL refers to the transmission direction from a UE 115 to a BS 105. The communication can be in the form of radio frames. A radio frame may be divided into a plurality of subframes or slots, for example, about 10. Each slot may be further divided into mini-slots. In a FDD mode, simultaneous UL and DL transmissions may occur in different frequency bands. For example, each subframe includes a UL subframe in a UL frequency band and a DL subframe in a DL frequency band. In a TDD mode, UL and DL transmissions occur at different time periods using the same frequency band. For example, a subset of the subframes (e.g., DL subframes) in a radio frame may be used for DL transmissions and another subset of the subframes (e.g., UL subframes) in the radio frame may be used for UL transmissions.

The DL subframes and the UL subframes can be further divided into several regions. For example, each DL or UL subframe may have pre-defined regions for transmissions of reference signals, control information, and data. Reference signals are predetermined signals that facilitate the communications between the BSs 105 and the UEs 115. For example, a reference signal can have a particular pilot pattern or structure, where pilot tones may span across an operational BW or frequency band, each positioned at a pre-defined time and a pre-defined frequency. For example, a BS 105 may transmit cell specific reference signals (CRSs) and/or channel state information –reference signals (CSI-RSs) to enable a UE 115 to estimate a DL channel. Similarly, a UE 115 may transmit sounding reference signals (SRSs) to enable a BS 105 to estimate a UL channel. Control information may include resource assignments and protocol controls. Data may include protocol data and/or operational data. In some aspects, the BSs 105 and the UEs 115 may communicate using self-contained subframes. A self-contained subframe may include a portion for DL communication and a portion for UL communication. A self-contained subframe can be DL-centric or UL-centric. A DL-centric subframe may include a longer duration for DL communication than for UL communication. A UL-centric subframe may include a longer duration for UL communication than for DL communication.

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

In some aspects, a UE 115 attempting to access the network 100 may perform an initial cell search by detecting a PSS from a BS 105. The PSS may enable synchronization of period timing and may indicate a physical layer identity value. The UE 115 may then receive a SSS. The SSS may enable radio frame synchronization, and may provide a cell identity value, which may be combined with the physical layer identity value to identify the cell. The PSS and the SSS may be located in a central portion of a carrier or any suitable frequencies within the carrier.

After receiving the PSS and SSS, the UE 115 may receive a 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 RMSI and/or OSI. The RMSI and/or OSI may include radio resource control (RRC) information related to random access channel (RACH) procedures, paging, control resource set (CORESET) for physical downlink control channel (PDCCH) monitoring, physical UL control channel (PUCCH) , physical UL shared channel (PUSCH) , power control, and SRS.

After obtaining the MIB, the RMSI and/or the OSI, the UE 115 can 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 transmit 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, a UL grant, a temporary cell-radio network temporary identifier (C-RNTI) , and/or a backoff indicator. Upon receiving the random access response, the UE 115 may transmit a connection request to the BS 105 and the BS 105 may respond with a connection response. The connection response may indicate a contention resolution. In some examples, the random access preamble, the RAR, the connection request, and the connection response can 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 transmit a random access preamble and a connection request in a single transmission and the BS 105 may respond by transmitting a random access response and a connection response in a single transmission.

After establishing a connection, the UE 115 and the BS 105 can enter a normal operation stage, where operational data may be exchanged. For example, the BS 105 may schedule the UE 115 for UL and/or DL communications. The BS 105 may transmit UL and/or DL scheduling grants to the UE 115 via a PDCCH. The scheduling grants may be transmitted in the form of DL control information (DCI) . The BS 105 may transmit a DL communication signal (e.g., carrying data) to the UE 115 via a PDSCH according to a DL scheduling grant. The UE 115 may transmit a UL communication signal to the BS 105 via a PUSCH and/or PUCCH according to a UL scheduling grant.

In some aspects, the BS 105 may communicate with a UE 115 using HARQ techniques to improve communication reliability, for example, to provide a URLLC service. The BS 105 may schedule a UE 115 for a PDSCH communication by transmitting a DL grant in a PDCCH. The BS 105 may transmit a DL data packet to the UE 115 according to the schedule in the PDSCH. The DL data packet may be transmitted in the form of a transport block (TB) . If the UE 115 receives the DL data packet successfully, the UE 115 may transmit a HARQ ACK to the BS 105. Conversely, if the UE 115 fails to receive the DL transmission successfully, the UE 115 may transmit a HARQ NACK to the BS 105. Upon receiving a HARQ NACK from the UE 115, the BS 105 may retransmit the DL data packet to the UE 115. The retransmission may include the same coded version of DL data as the initial transmission. Alternatively, the retransmission may include a different coded version of the DL data than the initial transmission. The UE 115 may apply soft-combining to combine the encoded data received from the initial transmission and the retransmission for decoding. The BS 105 and the UE 115 may also apply HARQ for UL communications using substantially similar mechanisms as the DL HARQ.

In some aspects, the network 100 may operate over a system BW or a component carrier (CC) BW. The network 100 may partition the system BW into multiple BWPs (e.g., portions) . A BS 105 may dynamically assign a UE 115 to operate over a certain BWP (e.g., a certain portion of the system BW) . The assigned BWP may be referred to as the active BWP. The UE 115 may monitor the active BWP for signaling information from the BS 105. The BS 105 may schedule the UE 115 for UL or DL communications in the active BWP. In some aspects, a BS 105 may assign a pair of BWPs within the CC to a UE 115 for UL and DL communications. For example, the BWP pair may include one BWP for UL communications and one BWP for DL communications.

In some aspects, the network 100 may operate over a shared channel, which may include shared frequency bands or unlicensed frequency bands. For example, the network 100 may be an NR-unlicensed (NR-U) network operating over an unlicensed frequency band. In such an aspect, the BSs 105 and the UEs 115 may be operated by multiple network operating entities. To avoid collisions, the BSs 105 and the UEs 115 may employ an LBT procedure to monitor for transmission opportunities (TXOPs) in the shared channel. A wireless communication device may perform an LBT in the shared channel. LBT is a channel access scheme that may be used in the unlicensed spectrum. When the LBT results in an LBT pass (the wireless communication device wins contention for the wireless medium) , the wireless communication device may access the shared medium to transmit and/or receive data. For example, a transmitting node (e.g., a BS 105 or a UE 115) may perform an LBT prior to transmitting in the channel. When the LBT passes, the transmitting node may proceed with the transmission. When the LBT fails, the transmitting node may refrain from transmitting in the channel. In an example, the LBT may be based on energy detection. For example, the LBT results in a pass when signal energy measured from the channel is below a threshold. Conversely, the LBT results in a failure when signal energy measured from the channel exceeds the threshold. In another example, the LBT may be based on signal detection. For example, the LBT results in a pass when a channel reservation signal (e.g., a predetermined preamble signal) is not detected in the channel. Conversely, the LBT results in a failure when a channel reservation signal is detected in the channel. A TXOP may also be referred to as channel occupancy time (COT) .

Sidelink communication refers to the communications among UEs without tunneling through a BS and/or a core network. For example, sidelink communications may refer to communications between two devices without going through a BS. Sidelink communication can be communicated over a physical sidelink control channel (PSCCH) and a physical sidelink shared channel (PSSCH) . The PSCCH and PSSCH are analogous to a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH) in downlink (DL) communication between a BS and a UE. For instance, the PSCCH may carry sidelink control information (SCI) and the PSSCH may carry SCI and/or sidelink data (e.g., user data) . Each PSCCH is associated with a corresponding PSSCH, where SCI in a PSCCH may carry reservation and/or scheduling information for sidelink data transmission in the associated PSSCH. In some examples, a UE may transmit PSSCH carrying SCI, which may be indicated in two stages. In a first stage control (SCI-1) , the UE may transmit PSCCH carrying information for resource allocation and decoding a second stage control. The first stage SCI may include at least one of a priority, PSSCH resource assignment, resource reservation period (if enabled) , PSSCH DMRS pattern (if more than one pattern is configured) , a second-stage SCI format (e.g., size of 2nd SCI) , an amount of resources for the second-stage SCI, a number of PSSCH demodulation reference signal (DMRS) port (s) , a modulation and coding scheme (MCS) , etc. In a second stage control (SCI-2) , the UE may transmit PSCCH carrying information for decoding the PSSCH. The second stage SCI may include a -bit L1 destination identifier (ID) , an 8-bit L1 source ID, a HARQ process ID, a new data indicator (NDI) , a redundancy version (RV) , etc. Sidelink communication can also be communicated over a physical sidelink feedback control channel (PSFCH) , which indicates an acknowledgement (ACK) -negative acknowledgement (NACK) for a previously transmitted PSSCH. Use cases for sidelink communication may include vehicle-to-everything (V2X) , industrial IoT (IIoT) , and/or NR-lite.

Some of the UEs 115 may communicate with each other in peer-to-peer communications. For example, a first UE may communicate with a second UE over a sidelink. In some instances, the sidelink may be a unicast bidirectional link, each between a pair of UEs. In some other instances, the sidelink may be multicast links supporting multicast sidelink services among the UEs. For instance, the first UE may transmit multicast data to the second UE over sidelinks. In some aspects, some of the UEs are associated with vehicles (e.g., similar to the UEs 115i-k in FIG. 1) and the communications over the sidelinks may be C-V2X communications. C-V2X communications may refer to communications between vehicles and any other wireless communication devices in a cellular network.

NR supports two modes of radio resource allocations (RRA) , a mode-1 RRA and a mode-2 RRA, for sidelink over a licensed spectrum. The mode-1 RRA supports network controlled RRA that can be used for in-coverage sidelink communication. For instance, a serving BS may determine a radio resource on behalf of a sidelink UE and transmit an indication of the radio resource to the sidelink UE. The serving BS may provide a dynamic grant or may activate a configured sidelink grant for sidelink communications. Sidelink feedback can be reported back to the BS by the transmitting UE. The mode-2 RRA supports autonomous RRA for sidelink UEs to perform autonomous sidelink communications over a shared radio frequency band (e.g., in a shared radio spectrum or an unlicensed spectrum) . In some aspects, the shared radio frequency band may be partitioned into multiple subchannels or frequency subbands. A sidelink UE may be configured to operate in a mode-2 RRA. For instance, the sidelink UE may be configured with a resource pool in the shared radio frequency band. Additionally, the channel access may be in units of sidelink communication frames in time. Each sidelink communication frame may include an LBT gap duration followed by a sidelink resource. A sidelink UE intending to transmit in a frequency subband may perform an LBT in the LBT gap duration. If the LBT is successful, the sidelink UE may proceed to transmit SCI and/or sidelink data in the following sidelink resource.

FIG. 2 is a timing diagram illustrating a transmission frame structure 200 according to one or more aspects of the present disclosure. The transmission frame structure 200 may be employed by BSs such as the BSs 105 and UEs such as the UEs 115 in a network such as the network 100 for communications. The BS may communicate with the UE using time-frequency resources configured as shown in the transmission frame structure 200. Additionally or alternatively, sidelink UEs may autonomously select sidelink resources or identify sidelink resources with network assistance from the BS for sidelink communications. For example, a first sidelink UE may communicate with another sidelink UE using time-frequency resources configured as shown in the transmission frame structure 200. In FIG. 2, the x-axes represent time in some arbitrary units, and the y-axes represent frequency in some arbitrary units.

The transmission frame structure 200 includes a radio frame 201. The duration of the radio frame 201 may vary depending on some aspects. In an example, the radio frame 201 may have a duration of about ten milliseconds. The radio frame 201 includes M number of slots 202, where M may be any suitable positive integer. In an example, M may be about 10.

Each slot 202 includes a number of subcarriers 204 in frequency and a number of symbols 206 in time. The number of subcarriers 204 and/or the number of symbols 206 in a slot 202 may vary depending on, for example, the channel bandwidth, the subcarrier spacing (SCS) , and/or the cyclic-prefix (CP) mode. One subcarrier 204 in frequency and one symbol 206 in time forms one resource element (RE) 212 for transmission. A resource block (RB) 210 is formed from a number of consecutive subcarriers 204 in frequency and a number of consecutive symbols 206 in time. A resource block group (RBG) may include one or more RBs. A subband may include multiple RBGs.

In an example, a sidelink UE (e.g., UE 115 in FIG. 1) may schedule a sidelink transmission for UL and/or DL communications at a time-granularity of slots 202 or mini-slots 208. Each slot 202 may be time-partitioned into P number of mini-slots 208. Each mini-slot 208 may include one or more symbols 206. The mini-slots 208 in a slot 202 may have variable lengths. For example, when a slot 202 includes N number of symbols 206, a mini-slot 208 may have a length between one symbol 206 and (N-1) symbols 206. In some aspects, a mini-slot 208 may have a length of about two symbols 206, about four symbols 206, or about seven symbols 206. In some examples, the BS 105 may schedule the UE 115 at a frequency-granularity of a RB 210 (e.g., including about 12 subcarriers 204) .

A sidelink UE (e.g., UE 115) may transmit a sidelink communication to another sidelink UE in a slot. If SCS is about 60 kHz, the TTI duration may be about 0.25 ms, with each symbol length being about 16.67 μs. The smaller the SCS, the longer the OFDM symbol duration. Accordingly, the gap duration and the AGC duration may be shorter for SCS that is smaller than 60 KHz. For example, if the SCS is about 15 kHz, the data symbol duration may be about four times as long as the data symbol duration of 60 kHz SCS. In another example, if the SCS is about 30 kHz, the data symbol duration may be about two times as long as the data symbol duration of 60 kHz SCS.

The UE may communicate the sidelink transmission with a CP extension provide a duration for AGC and create a transmission gap to reduce resource utilization overhead. For example, if each of the AGC duration and the gap duration is shorter than a symbol duration, then more resources may be provided to transmit PSCCH/PSSCH and/or communication PSFCH (e.g., receive PSFCH or transmit PSFCH) .

The present disclosure provides techniques for controlling one or more AGC durations and/or one or more transmission gap durations in a slot-based transmission. One way to provide an AGC duration and a gap duration is to apply a CP extension to a transmission. In an example, to apply a CP extension to a signal including symbols 0 to K, a sidelink UE may generate the CP extension and attach the CP extension to a beginning of the signal. For example, if the signal includes symbols 0 to K, the sidelink UE may generate the CP extension by copying an ending portion of symbol 0. After generating the CP extension, the sidelink UE may attach the CP extension to the beginning of the symbol 0. The gap duration may be created by applying the CP extension to the transmission, and the AGC duration may use the CP extension. In some aspects, the CP extension length may be based on SCS of the sidelink transmission. In some aspects, the CP extension length may be based on a capability of the sidelink UE. For example, different UEs may desire a different amount of time to determine the gain and to apply the gain in relation to the AGC duration.

In some aspects, a sidelink UE may determine a CP extension length to provide the AGC duration and the gap duration for a sidelink transmission and apply a CP extension having the CP extension length to the sidelink transmission. The sidelink UE may transmit the sidelink transmission with the CP extension. Mechanisms for providing the AGC duration and the gap duration using a CP extension are described in greater detail herein

FIG. 3 illustrates a sidelink slot structure scheme 300 for PSCCH/PSSCH transmission according to one or more aspects of the present disclosure. The scheme 300 may be employed by a UE 115 in a network such as the network 100. The network may support sidelink transmissions with a CP extension between sidelink UEs. The x-axis represents time in some arbitrary units, and the y-axis represents frequency in some arbitrary units.

In the example illustrated in FIG. 3, a frequency band 302 may be a shared radio frequency band or an unlicensed band shared by a plurality of network operating entities. The frequency band 302 may, for example, have a BW of about 10 megahertz (MHz) or about 20 MHz and a subcarrier spacing (SCS) of about 15 kHz, about 30 kHz, or about 60 kHz. The frequency band 302 may be located at any suitable frequencies. In some aspects, the frequency band 302 may be located at about 2.5 GHz, 6 GHz, or 20 GHz.

A UE 115 may communicate with one or more other UEs over a sidelink using the sidelink slot structure scheme 300. For example, the UE 115 may transmit a sidelink communication 314 in a slot 304 to another sidelink UE in the frequency band 302. The sidelink communication 314 may be a slot-based transmission that includes PSCCH/PSSCH but is devoid of PSFCH. Additionally, the slot 304 may correspond to a slot 202 in FIG. 2 and may include a plurality of symbols. A duration of the slot 304 may span any suitable number of symbols (e.g., OFDM symbols) . In some aspects, the duration of the slot 304 may correspond to one TTI, which may include about fourteen symbols.

In the example illustrated in FIG. 3, the slot 304 includes fourteen symbols (e.g., symbol 0, symbol 1, symbol 2, and so on, to symbol 13) . In the slot 304, the symbol 0 is at the beginning of the slot 304 and includes a gap duration 306 and an AGC duration 308. For example, the gap duration 306 is at a first half symbol of the symbol 0 and the AGC duration 308 is at a second half symbol of the symbol 0. A half symbol may refer to the midpoint or about the midpoint of a full symbol in time. In other words, a half symbol may have a duration of half or about half of a full symbol.

The UE 115 may transmit PSCCH/PSSCH in thirteen consecutive symbols (e.g.,

symbols

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and/or 13) of the slot 304, where PSSCH may extend to the last symbol 13 of the slot 304 (rather than providing a gap duration in the last symbol 13 of the slot 304) . Accordingly, the UE 115 may transmit PSSCH in the last symbol (e.g., symbol 13) of the slot 304 instead of having to leave the last symbol as a transmission gap for a transmission in a subsequent slot as in the first sidelink slot structure configuration discussed above.

In some aspects, the UE 115 may determine a CP extension length 312 to provide the gap duration 306 and the AGC duration 308 for the sidelink communication 314. The UE 115 may apply a CP extension 310 having the CP extension length 312 to the sidelink communication 314. The UE 115 may provide the gap duration 306 by applying the CP extension 310 to the sidelink communication 314. The CP extension length 312 may have the same value as the AGC duration 308. In other words, the AGC duration 308 may correspond to the CP extension 310 and a corresponding receiver may perform AGC training during the CP extension 310. Each of the CP extension length 312 and the AGC duration 308 may be less than a duration of a given symbol (e.g., symbol 1) , and the AGC duration 308 maybe followed by the given symbol. Additionally or alternatively, the CP extension length 312 may be based on an SCS of the sidelink transmission. The scheme 300 may apply to SCS of 15 kHz or 30 kHz.

To transmit the sidelink communication 314 in the slot 304, the UE 115 may contend for a COT in the frequency band 302, which may be a shared radio frequency band and/or an unlicensed band, for sidelink communication with another UE over a sidelink. To communicate the sidelink communication 314 over the frequency band 302, the UE 115 may perform an LBT during the gap duration 306 to contend for the COT. LBT may refer to a channel sensing mechanism used by devices (e.g., UE 115) to determine the presence of other signals in the channel prior to transmission and to avoid collisions with other transmissions. A device may sense the medium for a period of time. If the LBT fails, the UE 115 may refrain from transmitting in the frequency band 302. However, if the LBT is successful, the UE 115 may acquire the COT and transmit the sidelink communication 314 with the CP extension 310 in the slot 304. The sidelink communication 314 may include PSCCH/PSSCH (indicated by the patterned box corresponding to the sidelink transmission 306) in symbols 1-13 (as just one example) of the slot 304. The transmission of communications during any particular symbols, slots, etc., as discussed in the present disclosure, may be provided to provide examples and are not intended to be limiting.

FIG. 4 illustrates transmission of PSCCH/PSSCH in two adjacent slots using the sidelink slot structure scheme 300 according to one or more aspects of the present disclosure. FIG. 4 may use the same reference numerals as shown in FIG. 3 for simplicity’s sake. For example, the frequency band 302, the slot 304, the gap duration 306, the AGC duration 308, the CP extension 310, and the CP extension length 312 shown in FIG. 4 are discussed above in relation to FIG. 3.

The UE 115 may transmit a sidelink communication 414 in a slot 404. The slot 404 may have the same slot structure as the slot 304. The slot 404 may include, for example, fourteen symbols, with the last four symbols of the slot 404 being

symbols

10, 11, 12, and 13. The UE 115 may transmit the sidelink communication 414 including PSCCH/PSSCH in the slot 414, which immediately precedes the slot 304. A first slot immediately precedes a second slot if the first slot occurs before the second slot and no other slots are located between the first and second slots. In the example illustrated in FIG. 4, the UE 115 may transmit the PSCCH/PSSCH in a last symbol of the slot 404. The last symbol of the slot 404 is shown as being symbol 13, which is adjacent to the beginning symbol 0 of the slot 304. As discussed above, the symbol 0 of slot 304 includes the gap duration 306 at a first half symbol of the symbol 0 and the AGC duration 308 at a second half symbol of the symbol 0.

FIG. 5 illustrates a sidelink slot structure scheme 500 for PSFCH transmission according to one or more aspects of the present disclosure. The scheme 500 may be employed by a UE 115 in a network such as the network 100. The network may support sidelink transmissions with a CP extension between sidelink UEs. The x-axis represents time in some arbitrary units, and the y-axis represents frequency in some arbitrary units.

In the example illustrated in FIG. 5, a frequency band 502 may be a shared radio frequency band or an unlicensed band shared by a plurality of network operating entities. The frequency band 502 may, for example, have a BW of about 10 megahertz (MHz) or about 20 MHz and a subcarrier spacing (SCS) of about 15 kHz, about 30 kHz, or about 60 kHz. The frequency band 502 may be located at any suitable frequencies. In some aspects, the frequency band 502 may be located at about 2.5 GHz, 6 GHz, or 20 GHz.

A UE 115 may communicate with one or more other UEs over a sidelink using the sidelink slot structure scheme 500. For example, the UE 115 may communicate a sidelink transmission in a slot 504 to another sidelink UE in the frequency band 502. The sidelink transmission may include, for example, PSCCH/PSSCH communication 514 and/or PSFCH communication 516. The PSCCH/PSSCH transmission 514 and the PSFCH communication 516 may be a slot-based transmission. For example, the UE 115 may transmit the PSCCH/PSSCH transmission to a sidelink UE in the slot 504. In another example, the UE 115 may transmit the PSFCH communication 516 to a sidelink UE in the slot 504. In another example, the UE 115 may receive the PSFCH communication 516 from a sidelink UE in the slot 504.

The slot 504 may correspond to a slot 202 in FIG. 2 and may include a plurality of symbols. A duration of the slot 504 may span any suitable number of symbols (e.g., OFDM symbols) . In some aspects, the duration of the slot 504 may correspond to one TTI, which may include about fourteen symbols. In the example illustrated in FIG. 5, the slot 504 includes fourteen symbols (e.g., symbol 0, symbol 1, symbol 2, and so on, to symbol 13) . In the slot 504, the symbol 0 is at the beginning of the slot 504 and includes a gap duration 506 and an AGC duration 508. For example, the gap duration 506 is at a first half symbol of the symbol 0 and the AGC duration 508 is at a second half symbol of the symbol 0.

The UE 115 may transmit PSCCH/PSSCH in eleven consecutive symbols (e.g.,

symbols

1, 2, 5, 6, 5, 6, 7, 8, 9, 10, and/or 11) of the slot 504, where PSSCH may extend to the

symbols

10 and 11 of the slot 304 (rather than providing a gap duration in symbol 10 and/or transmitting a repetition of symbol 12 in symbol 11 of the slot 304) . Accordingly, the UE 115 may transmit PSSCH in

symbols

10 and 11 of the slot 504.

In some aspects, the UE 115 may determine a CP extension length 512 to provide the gap duration 506 and the AGC duration 508 for the PSCCH/PSSCH transmission 514. The UE 115 may apply a CP extension 510 having the CP extension length 512 to the PSCCH/PSSCH transmission 514. The UE 115 may provide the gap duration 506 by applying the CP extension 510 to the PSCCH/PSSCH transmission 514. The CP extension length 512 may have the same value as the AGC duration 508. In other words, the AGC duration 508 may correspond to the CP extension 510 and a corresponding receiver may perform AGC training during the CP extension 310. Each of the CP extension length 512 and the AGC duration 508 may be less than a duration of a given symbol (e.g., symbol 1) , and the AGC duration 508 may be followed by the given symbol. Additionally or alternatively, the CP extension length 512 may be based on an SCS of the sidelink transmission. The SCS may be, for example, about 15 kHz or about 30 kHz. The scheme 500 may apply to SCS of 15 kHz or 30 kHz.

To transmit the PSCCH/PSSCH transmission 514 in the slot 504, the UE 115 may contend for a COT in the frequency band 502, which may be a shared radio frequency band and/or an unlicensed band, for sidelink communication with another UE over a sidelink. To transmit the PSCCH/PSSCH transmission 514 over the frequency band 502, the UE 115 may perform an LBT during the gap duration 506 to contend for the COT. If the LBT fails, the UE 115 may refrain from transmitting in the frequency band 502. However, if the LBT is successful, the UE 115 may acquire the COT and transmit the PSCCH/PSSCH transmission 514 with the CP extension 510 in the slot 504. In some instances, the gap duration 506 may satisfy a no LBT duration threshold (e.g., less than about 16 microseconds) , and thus the UE 115 may not perform an LBT prior to the PSCCH/PSSCH transmission 514.

The UE 115 may communicate (e.g., transmit or receive) the PSFCH communication 516 in a last symbol of the slot 504 (rather than providing a gap duration in the last symbol of the slot 504 for a next transmission adjacent to the last symbol) . The last symbol of the slot 504 is symbol 13. Accordingly, the UE 115 may communicate the PSFCH communication 516 in symbol 13 of the slot 504. In the slot 504, the symbol 12 immediately precedes the last symbol of the slot 504 and includes a gap duration 526 and an AGC duration 528. For example, the gap duration 526 is at a first half symbol of the symbol 12 and the AGC duration 528 is at a second half symbol of the symbol 12 (rather than communicating a PSFCH communication in the symbol 12 of the slot 504) .

In some aspects, the UE 115 may determine a CP extension length 532 to provide the gap duration 526 and the AGC duration 528 for the PSFCH communication 516. The UE 115 may apply a CP extension 540 having the CP extension length 532 to the PSFCH communication 516. The UE 115 may provide the gap duration 526 by applying the CP extension 540 to the PSFCH communication 516. The CP extension length 532 may have the same value as the AGC duration 528. In other words, the AGC duration 528 may use the CP extension 540. Each of the CP extension length 532 and the AGC duration 528 may be less than a duration of a given symbol (e.g., symbol 13) , and the AGC duration 528 may be followed by the given symbol. Additionally or alternatively, the CP extension length 532 may be based on an SCS of the sidelink transmission. The SCS may be, for example, about 15 kHz or about 30 kHz.

The UE 115 may receive the PSFCH communication 516 during the symbol 13 in the slot 504. To transmit the PSFCH communication 516 in the slot 504, the UE 115 may contend for a COT in the frequency band 502, which may be a shared radio frequency band and/or an unlicensed band, for sidelink communication with another UE over a sidelink. To transmit the PSFCH communication 516 over the frequency band 502, the UE 115 may perform an LBT during the gap duration 526 to contend for the COT. If the LBT fails, the UE 115 may refrain from transmitting in the frequency band 502. However, if the LBT is successful, the UE 115 may acquire the COT and transmit the PSFCH communication 516 with the CP extension 540 in the slot 504.

In some examples, the UE may transmit a sidelink transmission including the PSCCH/PSSCH transmission 514 with the CP extension 510 and including the PSFCH transmission 516 with the CP extension 540. The CP extension 540 is located between the symbol 11 and the symbol 13 of the slot 504. As discussed, the UE 115 may transmit PSSCH in a plurality of symbols including

consecutive symbols

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and/or 11.

FIG. 6 illustrates transmission of PSCCH/PSSCH and PSFCH in two adjacent slots using the sidelink slot structure scheme 500 according to one or more aspects of the present disclosure. FIG. 6 may use the same reference numerals as shown in FIG. 5 for simplicity’s sake. For example, the frequency band 502, the slot 504, the gap duration 506, the AGC duration 508, the CP extension 510, the CP extension length 512, and the PSCCH/PSSCH transmission 514 shown in FIG. 6 are discussed above in relation to FIG. 5.

The UE 115 may communicate a sidelink communication including a PSCCH/PSSCH transmission 614 and/or a PSFCH communication 616 in a slot 604. The slot 604 may have the same slot structure as the slot 504. The slot 604 may include, for example, fourteen symbols, with the last four symbols of the slot 604 being

symbols

10, 11, 12, and 13. The UE 115 may transmit the PSCCH/PSSCH transmission 614 during the

symbols

10 and 11 of slot 604, which immediately precedes the slot 504. Additionally or alternatively, the UE may transmit or receive the PSFCH communication 616 during the symbol 13 of slot 604. For example, the UE 115 may transmit the PSFCH communication 616 in a last symbol of the slot 604. The last symbol of the slot 604 is shown as being symbol 13, which is adjacent to the beginning symbol 0 of the slot 504. As discussed above, the symbol 0 of slot 504 includes the gap duration 506 at a first half symbol of the symbol 0 and the AGC duration 508 at a second half symbol of the symbol 0.

FIG. 7 illustrates a sidelink slot structure scheme 700 for PSCCH/PSSCH transmission according to one or more aspects of the present disclosure. The scheme 700 may be employed by a UE 115 in a network such as the network 100. The network may support sidelink transmissions with a CP extension between sidelink UEs. The x-axis represents time in some arbitrary units, and the y-axis represents frequency in some arbitrary units.

In the example illustrated in FIG. 7, a frequency band 702 may be a shared radio frequency band or an unlicensed band shared by a plurality of network operating entities. The frequency band 702 may, for example, have a BW of about 10 megahertz (MHz) or about 20 MHz and a subcarrier spacing (SCS) of about 15 kHz, about 30 kHz, or about 60 kHz. The frequency band 702 may be located at any suitable frequencies. In some aspects, the frequency band 702 may be located at about 2.5 GHz, 6 GHz, or 20 GHz.

A UE 115 may communicate with one or more other UEs over a sidelink using the sidelink slot structure scheme 700. For example, the UE 115 may transmit a sidelink communication 714 in a slot 704 to another sidelink UE in the frequency band 702. The sidelink communication 714 may be a slot-based transmission that includes PSCCH/PSSCH but is devoid of PSFCH. Additionally, the slot 704 may correspond to a slot 202 in FIG. 2 and may include a plurality of symbols. A duration of the slot 704 may span any suitable number of symbols (e.g., OFDM symbols) . In some aspects, the duration of the slot 704 may correspond to one TTI, which may include about fourteen symbols.

In the example illustrated in FIG. 7, the UE 115 may shift a symbol boundary of the slot 704 by half a symbol after a beginning half symbol. The UE 115 may transmit a PSCCH/PSSCH of the sidelink communication 714 in accordance with the shifted symbol boundary. In FIG. 7, the slot 704 includes a plurality of symbols including a first set of symbols and a second set of symbols. The first set of symbols includes thirteen consecutive symbols 1-13, each having a full symbol length 730 (e.g., an OFDM symbol period) . The second set of symbols includes a symbol 0 and a symbol 13’ of the slot 704, each having a half symbol length 732 (e.g., half OFDM symbol period) . The symbol 0 precedes the first set of symbols, and the symbol 13’s ucceeds the first set of symbols. The symbol 0 is located at the beginning of the slot 704, and the symbol 13’ is located at an end of the slot 704. The first set of symbols is located between the symbol 0 and the symbol 13’ in the slot 704. Additionally, the half symbol length 732 may be half or about half of the full symbol length 730. In an example, the SCS is about 15 kHz, and the full symbol length may be about 66.68 μs. In another example, the SCS is about 30 kHz, and the full symbol length may be about 33.34 μs.

In the slot 704, the symbol 0 (a half symbol) is at the beginning of the slot 704 and includes a gap duration 706 and an AGC duration 708. For example, the gap duration 706 is at a first half symbol of the symbol 0 and the AGC duration 708 is at a second half symbol of the symbol 0. In other words, each of the gap duration 706 and the AGC duration 706 is a quarter of the full symbol length 730. The gap duration 706 is followed by the AGC duration 708 in symbol 0.

The UE 115 may transmit PSCCH/PSSCH in the first set of symbols (e.g.,

consecutive symbols

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and/or 13) of the slot 704. In some instances, the UE 115 may utilize the last half symbol 13’ of the slot 704 for a data transmission (e.g., PSSCH) . In some other instances, the UE 115 may utilize the last half symbol 13’ of the slot 704 for a reference signal transmission (e.g., a physical waveform transmission, for example, similar to an SRS) . For instance, the reference signal may be a physical waveform sequence. Accordingly, PSSCH may extend 1 to 13.5 consecutive symbols, from symbol 1 to the last half symbol 13’ of the slot 704 (rather than providing a gap duration in the last symbol of the slot 704 for a next transmission adjacent to the last symbol) .

In some aspects, the UE 115 may determine a CP extension length 712 to provide the gap duration 706 and the AGC duration 708 for the sidelink communication 714. The UE 115 may apply a CP extension 710 having the CP extension length 712 to the sidelink communication 714. The UE 115 may provide the gap duration 706 by applying the CP extension 710 to the sidelink communication 714. The CP extension length 712 may have the same value as the AGC duration 708. In other words, the AGC duration 708 may use the CP extension 710. Each of the CP extension length 712 and the AGC duration 708 may be less than a duration of a given symbol (e.g., symbol 1) , and the AGC duration 708 may be followed by the given symbol. Additionally or alternatively, the CP extension length 712 may be based on an SCS of the sidelink transmission. The scheme 700 may apply to SCS of 15 kHz or 30 kHz. Additionally or alternatively, the CP extension length 712 may be based on the UE 115’s capability.

To transmit the sidelink communication 714 in the slot 704, the UE 115 may contend for a COT in the frequency band 702, which may be a shared radio frequency band and/or an unlicensed band, for sidelink communication with another UE over a sidelink. To communicate the sidelink communication 714 over the frequency band 702, the UE 115 may perform an LBT during the gap duration 706 to contend for the COT. If the LBT fails, the UE 115 may refrain from transmitting in the frequency band 702. However, if the LBT is successful, the UE 115 may acquire the COT and transmit the sidelink communication 714 with the CP extension 710 in the slot 704. The sidelink communication 714 may include PSCCH/PSSCH (indicated by the patterned box corresponding to the sidelink transmission 714) in symbols 1-13 and 13’ (as just one example) of the slot 704.

FIG. 8 illustrates a sidelink slot structure scheme 800 for PSFCH transmission according to one or more aspects of the present disclosure. The scheme 800 may be employed by a UE 115 in a network such as the network 100. The network may support sidelink transmissions with a CP extension between sidelink UEs. The x-axis represents time in some arbitrary units, and the y-axis represents frequency in some arbitrary units.

In the example illustrated in FIG. 8, a frequency band 802 may be a shared radio frequency band or an unlicensed band shared by a plurality of network operating entities. The frequency band 802 may, for example, have a BW of about 10 megahertz (MHz) or about 20 MHz and a subcarrier spacing (SCS) of about 15 kHz, about 30 kHz, or about 60 kHz. The frequency band 802 may be located at any suitable frequencies. In some aspects, the frequency band 802 may be located at about 2.5 GHz, 6 GHz, or 20 GHz.

A UE 115 may communicate with one or more other UEs over a sidelink using the sidelink slot structure scheme 800. For example, the UE 115 may communicate a sidelink transmission in a slot 804 to another sidelink UE in the frequency band 802. The sidelink transmission may include, for example, PSCCH/PSSCH communication 814 and/or PSFCH communication 816. The PSCCH/PSSCH transmission 814 and the PSFCH communication 816 may be a slot-based transmission. For example, the UE 115 may transmit the PSCCH/PSSCH transmission to a sidelink UE in the slot 804. In another example, the UE 115 may transmit the PSFCH communication 816 to a sidelink UE in the slot 804. In another example, the UE 115 may receive the PSFCH communication 816 from a sidelink UE in the slot 804.

The slot 804 may correspond to a slot 202 in FIG. 2 and may include a plurality of symbols. A duration of the slot 804 may span any suitable number of symbols (e.g., OFDM symbols) . In some aspects, the duration of the slot 804 may correspond to one TTI, which may include about fourteen symbols. In the example illustrated in FIG. 8, the UE 115 may shift a symbol boundary of the slot 804 by half a symbol after a beginning half symbol. The UE 115 may transmit a sidelink communication (e.g., PSCCH/PSSCH 814 or PSFCH communication 816) in accordance with the shifted symbol boundary. In FIG. 8, the slot 804 includes a plurality of symbols including a first set of symbols and a second set of symbols. The first set of symbols includes twelve consecutive symbols 1-12, each having a full symbol length 830 (e.g., an OFDM symbol period) . The second set of symbols includes a symbol 0 and a symbol 12’ of the slot 804, each having a half symbol length 832 (e.g., half OFDM symbol period) . The symbol 0 precedes the first set of symbols, and the symbol 12’s ucceeds the first set of symbols. The symbol 0 is located at the beginning of the slot 704, and the symbol 12’ is located between full-length symbol 12 and full-length symbol 13 of the slot 704. The first set of symbols is located between the symbol 0 and the symbol 12’ in the slot 804. Additionally, the half symbol length 832 may be half or about half of the full symbol length 830. In an example, the SCS is about 15 kHz, and the full symbol length may be about 66.68 μs. In another example, the SCS is about 30 kHz, and the full symbol length may be about 33.34 μs.

In the slot 804, the symbol 0 (a half symbol) is at the beginning of the slot 804 and includes a gap duration 806 and an AGC duration 808. For example, the gap duration 806 is at a first half symbol of the symbol 0, and the AGC duration 808 is at a second half symbol of the symbol 0. In other words, each of the gap duration 806 and the AGC duration 806 is a quarter of the full symbol length 830. The gap duration 806 is followed by the AGC duration 808 in symbol 0.

The UE 115 may transmit PSCCH/PSSCH in the first set of symbols (e.g.,

consecutive symbols

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and/or 12) of the slot 804. Accordingly, PSSCH may extend 1 to 12 consecutive symbols, from symbol 1 to the symbol 12 of the slot 804 (rather than providing a gap duration in symbol 10 and/or transmitting a repetition of symbol 12 in symbol 11 of the slot 804) . Accordingly, the UE 115 may transmit PSSCH in

symbols

10 and 11 of the slot 804.

In some aspects, the UE 115 may determine a CP extension length 812 to provide the gap duration 806 and the AGC duration 808 for the PSCCH/PSSCH transmission 814. The UE 115 may apply a CP extension 810 having the CP extension length 812 to the PSCCH/PSSCH transmission 814. The UE 115 may provide the gap duration 806 by applying the CP extension 810 to the PSCCH/PSSCH transmission 814. The CP extension length 812 may have the same value as the AGC duration 808. In other words, the AGC duration 808 may use the CP extension 810. Each of the CP extension length 812 and the AGC duration 808 may be less than a duration of a given symbol (e.g., symbol 1) , and the AGC duration 808 may be followed by the given symbol. Additionally or alternatively, the CP extension length 812 may be based on an SCS of the sidelink transmission. The scheme 800 may apply to SCS of 15 kHz or 30 kHz.

To transmit the PSCCH/PSSCH transmission 814 in the slot 804, the UE 115 may contend for a COT in the frequency band 802, which may be a shared radio frequency band and/or an unlicensed band, for sidelink communication with another UE over a sidelink. To communicate the PSCCH/PSSCH transmission 814 over the frequency band 802, the UE 115 may perform an LBT during the gap duration 806 to contend for the COT. If the LBT fails, the UE 115 may refrain from transmitting in the frequency band 802. However, if the LBT is successful, the UE 115 may acquire the COT and transmit the PSCCH/PSSCH transmission 814 with the CP extension 810 in the slot 804. A sidelink transmission may include PSCCH/PSSCH (indicated by the patterned box corresponding to the PSCCH/PSSCH transmission 814) in symbols 1-12 (as just one example) of the slot 804.

The UE 115 may communicate (e.g., transmit or receive) the PSFCH communication 816 in a last symbol of the slot 804 (rather than providing a gap duration in the last symbol of the slot 804) . The last symbol of the slot 804 is symbol 13, which has a full symbol length 830. Accordingly, the UE 115 may communicate the PSFCH communication 816 in symbol 13 of the slot 804. In the slot 804, the symbol 12’ immediately precedes the last symbol of the slot 804 and has a half symbol length 832. The symbol 12’ includes a gap duration 826 and an AGC duration 828. For example, the gap duration 826 is at a first half symbol of the symbol 12’ , and the AGC duration 828 is at a second half symbol of the symbol 12’ . In other words, each of the gap duration 826 and the AGC duration 826 is a quarter of the full symbol length 830. The gap duration 826 is followed by the AGC duration 828 in symbol 12’ .

In some aspects, the UE 115 may determine a CP extension length 832 to provide the gap duration 826 and the AGC duration 828 for the PSFCH communication 816. The UE 115 may apply a CP extension 840 having the CP extension length 832 to the PSFCH communication 816. The UE 115 may provide the gap duration 826 by applying the CP extension 840 to the PSFCH communication 816. The CP extension length 832 may have the same value as the AGC duration 828. In other words, the AGC duration 828 may use the CP extension 840. Each of the CP extension length 832 and the AGC duration 828 may be less than a duration of a given symbol (e.g., symbol 13) and may be less than the half symbol length 832, and the AGC duration 828 may be followed by the given symbol. Additionally or alternatively, the CP extension length 832 may be based on an SCS of the sidelink transmission. The SCS may be, for example, about 15 kHz or about 30 kHz.

The UE 115 may receive the PSFCH communication 816 during the symbol 13 in the slot 804. To transmit the PSFCH communication 816 in the slot 804, the UE 115 may contend for a COT in the frequency band 802, which may be a shared radio frequency band and/or an unlicensed band, for sidelink communication with another UE over a sidelink. To transmit the PSFCH communication 816 over the frequency band 802, the UE 115 may perform an LBT during the gap duration 826 to contend for the COT. If the LBT fails, the UE 115 may refrain from transmitting in the frequency band 802. However, if the LBT is successful, the UE 115 may acquire the COT and transmit the PSFCH communication 816 with the CP extension 840 in the slot 804.

In some examples, the UE may transmit a sidelink transmission including the PSCCH/PSSCH transmission 814 with the CP extension 810 and including the PSFCH transmission 816 with the CP extension 840. The CP extension 840 is located between the symbol 12 and the symbol 13 of the slot 804. As discussed, the UE 115 may transmit PSSCH in a plurality of symbols including

consecutive symbols

1, 2, 3, 4, 8, 6, 7, 8, 9, 10, 11, and/or 12.

FIG. 9 illustrates a sidelink slot structure scheme 900 for PSCCH/PSSCH transmission according to one or more aspects of the present disclosure. The scheme 900 may be employed by a UE 115 in a network such as the network 100. The network may support sidelink transmissions with a CP extension between sidelink UEs. The x-axis represents time in some arbitrary units, and the y-axis represents frequency in some arbitrary units.

In the example illustrated in FIG. 9, a frequency band 902 may be a shared radio frequency band or an unlicensed band shared by a plurality of network operating entities. The frequency band 902 may, for example, have a BW of about 10 megahertz (MHz) or about 20 MHz and a subcarrier spacing (SCS) of about 15 kHz, about 30 kHz, or about 60 kHz. The frequency band 902 may be located at any suitable frequencies. In some aspects, the frequency band 902 may be located at about 2.5 GHz, 6 GHz, or 20 GHz.

A UE 115 may communicate with one or more other UEs over a sidelink using the sidelink slot structure scheme 900. For example, the UE 115 may transmit a

sidelink communication

914, 916, 918, 920 in a mini-slot 940a, 940b, 940c, and 940d, respectively, to another sidelink UE in the frequency band 902. The

sidelink communication

914, 916, 918, 920 may be a slot-based transmission that includes PSCCH/PSSCH but is devoid of PSFCH. Additionally, the slot 904 may correspond to a slot 202 in FIG. 2 and may include a plurality of symbols. A duration of the slot 904 may span any suitable number of symbols (e.g., OFDM symbols) . In some aspects, the duration of the slot 904 may correspond to one TTI, which may include about fourteen symbols. Each mini-slot 940a, 940b, 940c, and 940d may correspond to a TTI, which may carry a transport block for transmission.

In the example illustrated in FIG. 9, the UE 115 may shift a symbol boundary of the slot 904 by half a symbol after a beginning half symbol. The UE 115 may transmit a PSCCH/PSSCH of a sidelink communication in accordance with the shifted symbol boundary. In FIG. 9, the slot 904 includes four mini-slots 940a, 940b, 940c, and 940d, each mini-slot having a 3.5 symbol length in the slot 904. Each mini-slot includes a plurality of symbols including a first set of symbols and a second set of symbols. The first set of symbols includes three consecutive symbols used for a PSCCH/PSSCH transmission, each having a full symbol length 930 (e.g., an OFDM symbol period) . The second set of symbols includes a half symbol (e.g., half symbol 910 at the beginning of a mini-slot) that immediately precedes the first set of symbols, each symbol of the second set of symbols having a half symbol length 932 (e.g., half OFDM symbol period) . The half symbol length 932 may be half or about half of the full symbol length 930. In an example, the SCS is about 15 kHz, and the full symbol length may be about 66.68 μs. In another example, the SCS is about 30 kHz, and the full symbol length may be about 33.34 μs.

For example, the symbol 0 (a half symbol) is located at the beginning of the slot 904 and the beginning of the mini-slot 940a. The symbol 0 is the beginning symbol of the mini-slot 940a and is followed by the symbols 1-3. The symbol 3’ is the beginning symbol of the mini-slot 940b and is followed by the symbols 4-6. The symbol 7 is the beginning symbol of the mini-slot 940c and is followed by the symbols 8-10. The symbol 10’ is the beginning symbol of the mini-slot 940a and is followed by the symbols 11-13. In FIG. 9, the mini-slot 940a and the mini-slot 940c are on a half- symbol boundary rather than on a full-symbol boundary. Additionally, the mini-slot 940b and the mini-slot 940d are on a full-symbol boundary rather than on a half-symbol boundary.

As discussed, each mini-slot 940a, 940b, 940c, and 940d includes the beginning symbol having a half symbol length 932 followed by three consecutive symbols having the full symbol length 930. The UE 115 may transmit PSCCH/PSSCH in the first set of symbols (e.g., consecutive symbols 1-3, 4-6, 8-10, and/or 11-13) of the slot 904. The beginning symbol of the mini-slot includes a gap duration 906 and an AGC duration 908. For example, the gap duration 906 is at a first half symbol of the beginning symbol of the mini-slot, and the AGC duration 908 is at a second half symbol of the beginning symbol of the mini-slot. In other words, each of the gap duration 906 and the AGC duration 906 is a quarter of the full symbol length 930. The gap duration 906 is followed by the AGC duration 908 in the beginning symbol of the mini-slot.

In some aspects, the UE 115 may determine a CP extension length 912 to provide the gap duration 906 and the AGC duration 908 for the sidelink communication 914 in a mini-slot 940. The UE 115 may apply a CP extension 910 having the CP extension length 912 to the sidelink communication 914. The UE 115 may provide the gap duration 906 by applying the CP extension 910 to the sidelink communication 914. The CP extension length 912 may have the same value as the AGC duration 908. In other words, the AGC duration 908 may correspond to the CP extension 910 and a corresponding receiver may perform AGC training during the CP extension 910. Each of the CP extension length 912 and the AGC duration 908 may be less than a duration of a given symbol (e.g., symbol 1) , and the AGC duration 908 may be followed by the given symbol. Additionally or alternatively, the CP extension length 912 may be based on an SCS of the sidelink transmission. The scheme 900 may apply to SCS of 15 kHz or 30 kHz..

To transmit a PSCCH/PSSCH transmission in the slot 904, the UE 115 may contend for a COT in the frequency band 902, which may be a shared radio frequency band and/or an unlicensed band, for sidelink communication with another UE over a sidelink. For example, to transmit the PSCCH/PSSCH transmission in the symbols 1-3 of the mini-slot 940a, the UE 115 may perform an LBT during the gap duration 906 to contend for the COT. If the LBT fails, the UE 115 may refrain from transmitting in the frequency band 902. However, if the LBT is successful, the UE 115 may acquire the COT and transmit the PSCCH/PSSCH transmission with the CP extension 910 in the slot 904. The UE 115 may perform similar actions for PSCCH/PSSCH transmission in the mini-slot 940b, the mini-slot 940c, and/or the mini-slot 940d. A sidelink communication may include on one more PSCCH/PSSCH (indicated by the patterned box corresponding to symbols 1-3 in the mini-slot 940a, symbols 4-6 in the mini-slot 940b, symbols 8-10 in the mini-slot 940c, and/or symbols 11-13 in the mini-slot 940d of the slot 904.

FIG. 10 is a block diagram of an example UE 1000 according to one or more aspects of the present disclosure. The UE 1000 may be a UE 115 discussed above in FIG. 1. As shown, the UE 1000 may include a processor 1002, a memory 1004, a CP extension module 1008, a sidelink communication module 1009, a transceiver 1010 including a modem subsystem 1012 and a radio frequency (RF) unit 1014, and one or more antennas 1016. These elements may be in direct or indirect communication with each other, for example via one or more buses.

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

The memory 1004 may include a cache memory (e.g., a cache memory of the processor 1002) , random access memory (RAM) , magnetoresistive RAM (MRAM) , read-only memory (ROM) , programmable read-only memory (PROM) , erasable programmable read only memory (EPROM) , electrically erasable programmable read only memory (EEPROM) , flash memory, solid state memory device, hard disk drives, other forms of volatile and non-volatile memory, or a combination of different types of memory. In an aspect, the memory 1004 includes a non-transitory computer-readable medium. The memory 1004 may store, or have recorded thereon, instructions 1006. The instructions 1006 may include instructions that, when executed by the processor 1002, cause the processor 1002 to perform the operations described herein with reference to the UEs 115 in connection with aspects of the present disclosure, for example, aspects of FIGs. 1-9 and 12. Instructions 1006 may also be referred to as program code. The program code may be for causing a wireless communication device to perform these operations, for example by causing one or more processors (such as processor 1002) to control or command the wireless communication device to do so. The terms “instructions” and “code” should be interpreted broadly to include any type of computer-readable statement (s) . For example, the terms “instructions” and “code” may refer to one or more programs, routines, sub-routines, functions, procedures, etc. “Instructions” and “code” may include a single computer-readable statement or many computer-readable statements.

The CP extension module 1008 and/or the sidelink communication module 1009 may be implemented via hardware, software, or combinations thereof. For example, the CP extension module 1008 and/or the sidelink communication module 1009 may be implemented as a processor, circuit, and/or instructions 1006 stored in the memory 1004 and executed by the processor 1002. In some instances, the CP extension module 1008 and/or the sidelink communication module 1009 can be integrated within the modem subsystem 1012. For example, the CP extension module 1008 and/or the sidelink communication module 1009 can be implemented by a combination of software components (e.g., executed by a DSP or a general processor) and hardware components (e.g., logic gates and circuitry) within the modem subsystem 1012.

The CP extension module 1008 and/or the sidelink communication module 1009 may be used for various aspects of the present disclosure, for example, aspects of FIGs. 1-9 and 12. In some aspects, the CP extension module 1008 may be configured to determine a CP extension length to provide an AGC duration and a gap duration for a sidelink transmission. In some aspects, the CP extension module 1008 may be configured to apply a CP extension having the CP extension length to the sidelink transmission. In some aspects, the sidelink communication module 1009 may be configured to transmit the sidelink transmission with the CP extension.

As shown, the transceiver 1010 may include the modem subsystem 1012 and the RF unit 1014. The transceiver 1010 can be configured to communicate bi-directionally with other devices, such as the BSs 105 or other UEs (e.g., sidelink UEs) . The modem subsystem 1012 may be configured to modulate and/or encode the data from the memory 1004, the CP extension module 1008, and/or the sidelink communication module 1009 according to an MCS, e.g., a low-density parity check (LDPC) coding scheme, a turbo coding scheme, a convolutional coding scheme, a digital beamforming scheme, etc. The RF unit 1014 may be configured to process (e.g., perform analog to digital conversion or digital to analog conversion, etc. ) modulated/encoded data (e.g., PSSCH data and/or PSCCH control information, PSFCH ACK/NACK feedbacks, HARQ ACK/NACK) from the modem subsystem 1012 (on outbound transmissions) or of transmissions originating from another source such as a UE 115 or a BS 105. The RF unit 1014 may be further configured to perform analog beamforming in conjunction with the digital beamforming. Although shown as integrated together in transceiver 1010, the modem subsystem 1012 and the RF unit 1014 may be separate devices that are coupled together at the UE 1000 to enable the UE 1000 to communicate with other devices.

The RF unit 1014 may provide the modulated and/or processed data, e.g. data packets (or, more generally, data messages that may contain one or more data packets and other information) , to the antennas 1016 for transmission to one or more other devices. The antennas 1016 may further receive data messages transmitted from other devices. The antennas 1016 may provide the received data messages for processing and/or demodulation at the transceiver 1010. The transceiver 1010 may provide the demodulated and decoded data (e.g., PSSCH data and/or PSCCH control information, PSFCH ACK/NACK feedbacks, HARQ ACK/NACK) to the CP extension 1008 and/or the sidelink communication module 1009 for processing. The antennas 1016 may include multiple antennas of similar or different designs in order to sustain multiple transmission links. The RF unit 1014 may configure the antennas 1016.

In an example, the transceiver 1010 is configured to receive sidelink transmissions, PSCCH SCI, PSFCH ACK/NACK feedbacks from another UE, and/or sidelink COT sharing SCI, for example, by coordinating with the CP extension 1008. In an example, the transceiver 1010 is configured to transmit a sidelink transmission with a CP extension, PSSCH data, PSFCH ACK/NACK feedbacks to another UE and/or receive PSSCH data, for example, by coordinating with the CP extension 1008. In an aspect, the UE 1000 can include multiple transceivers 1010 implementing different RATs (e.g., NR and LTE) . In an aspect, the UE 1000 can include a single transceiver 1010 implementing multiple RATs (e.g., NR and LTE) . In an aspect, the transceiver 1010 can include various components, where different combinations of components can implement different RATs.

FIG. 11 is a block diagram of an example BS 1100 according to one or more aspects of the present disclosure. The BS 1100 may be a BS 105 in the network 100 as discussed above in FIG. 1. A shown, the BS 1100 may include a processor 1102, a memory 1104, a transceiver 1110 including a modem subsystem 1112 and a RF unit 1114, and one or more antennas 1116. These elements may be in direct or indirect communication with each other, for example via one or more buses.

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

The memory 1104 may include a cache memory (e.g., a cache memory of the processor 1102) , RAM, MRAM, ROM, PROM, EPROM, EEPROM, flash memory, a solid state memory device, one or more hard disk drives, memristor-based arrays, other forms of volatile and non-volatile memory, or a combination of different types of memory. In some aspects, the memory 1104 may include a non-transitory computer-readable medium. The memory 1104 may store instructions 1106. The instructions 1106 may include instructions that, when executed by the processor 1102, cause the processor 1102 to perform operations described herein, for example, at aspects of FIG. 1. Instructions 1106 may also be referred to as code, which may be interpreted broadly to include any type of computer-readable statement (s) as discussed above with respect to FIG. 10.

As shown, the transceiver 1110 may include the modem subsystem 1112 and the RF unit 1114. The transceiver 1110 can be configured to communicate bi-directionally with other devices, such as the UEs 115 and/or 1000 and/or another core network element. The modem subsystem 1112 may be configured to modulate and/or encode data according to a MCS, e.g., a LDPC coding scheme, a turbo coding scheme, a convolutional coding scheme, a digital beamforming scheme, etc. The RF unit 1114 may be configured to process (e.g., perform analog to digital conversion or digital to analog conversion, etc. ) modulated/encoded data (e.g., a sidelink resource configuration, sidelink COT sharing configuration) from the modem subsystem 1112 (on outbound transmissions) or of transmissions originating from another source such as a UE 115 and/or 1000. The RF unit 1114 may be further configured to perform analog beamforming in conjunction with the digital beamforming. Although shown as integrated together in transceiver 1110, the modem subsystem 1112 and/or the RF unit 1114 may be separate devices that are coupled together at the BS 105 to enable the BS 105 to communicate with other devices.

The RF unit 1114 may provide the modulated and/or processed data, e.g. data packets (or, more generally, data messages that may contain one or more data packets and other information) , to the antennas 1116 for transmission to one or more other devices. This may include, for example, transmission of information to complete attachment to a network and communication with a camped UE 115 or UE 1000 according to one or more aspects of the present disclosure. The antennas 1116 may further receive data messages transmitted from other devices and provide the received data messages for processing and/or demodulation at the transceiver 1110. The transceiver 1110 may provide the demodulated and decoded data to any modules of the BS 1100 for processing. The antennas 1116 may include multiple antennas of similar or different designs in order to sustain multiple transmission links.

In an aspect, the BS 1100 can include multiple transceivers 1110 implementing different RATs (e.g., NR and LTE) . In an aspect, the BS 1100 can include a single transceiver 1110 implementing multiple RATs (e.g., NR and LTE) . In an aspect, the transceiver 1110 can include various components, where different combinations of components can implement different RATs.

FIG. 12 illustrates a flow diagram of a communication method 1200 for transmitting a sidelink communication associated with a CP extension according to one or more aspects of the present disclosure. Blocks of the method 1200 can be executed by a computing device (e.g., a processor, processing circuit, and/or other suitable component) of a wireless communication device. In some aspects, the wireless communication device is a UE (e.g., UEs 115 and/or UE 1000) that may utilize one or more components, such as the processor 1002, the memory 1004, the CP extension module 1008, the sidelink communication module 4009, the transceiver 1010, and/or the antennas 1016 to execute the blocks of the method 1200. The method 1200 may employ similar aspects as in the transmission frame structure 200 in FIG. 2, the sidelink slot structure scheme 300 in FIG. 3, the sidelink slot structure scheme 500 in FIG. 5, the sidelink slot structure scheme 700 in FIG. 7, the sidelink slot structure scheme 800 in FIG. 8, and/or the sidelink slot structure scheme 900 in FIG. 9. As illustrated, the method 1200 includes a number of enumerated blocks, but aspects of the method 1200 may include additional blocks before, after, and/or in between the enumerated blocks. In some aspects, one or more of the enumerated blocks may be omitted or performed in a different order.

At block 1210, the method 1200 includes determining a CP extension length to provide an AGC duration and a gap duration for a sidelink transmission. The CP extension length may correspond to the AGC duration, which is shorter than a duration of a given symbol and is followed by the given symbol. In some aspects, the CP extension length is based on a SCS. The SCS may be, for example, about 15 kHz or about 30 KHz. In some aspects, the CP extension length is based on a capability of the sidelink UE.

At block 1220, the method 1200 includes applying a CP extension having the CP extension length to the sidelink transmission. In an example, to apply a CP extension to a signal including symbols 0 to K, a sidelink UE (e.g., UE 115) may generate the CP extension and attach the CP extension to a beginning of the signal. For example, if the signal includes symbols 0 to K, the sidelink UE may generate the CP extension by copying an ending portion of symbol 0. After generating the CP extension, the sidelink UE may attach the CP extension to the beginning of the symbol 0. The gap duration may be created by applying the CP extension to the transmission, and the AGC duration may use the CP extension.

At block 1230, the method 1200 includes transmitting the sidelink transmission with the CP extension. The sidelink UE may transmit the sidelink transmission in a slot including a plurality of symbols (e.g., about fourteen symbols) .

As an example illustrated in FIG. 3, a first symbol of the slot may include the gap duration and the AGC duration. The gap duration may be at a first half symbol of the first symbol, the AGC duration may be at a second half symbol of the first symbol, and the first symbol may be at the beginning of the slot. The sidelink transmission may be for a PSCCH/PSSCH transmission and may be devoid of PSFCH. In some instances, the sidelink UE may transmit PSCCH/PSSCH in thirteen consecutive symbols (e.g., symbols 1-13 in FIG. 3) including the last symbol of the slot.

As an example illustrated in FIG. 5, the sidelink UE may transmit PSCCH/PSSCH in a sidelink communication and/or may communicate PSFCH in a sidelink communication. If the sidelink UE transmits PSCCH/PSSCH in the slot 504, the sidelink UE may transmit PSCCH/PSSCH in up to eleven consecutive symbols (e.g., symbols 1-11 in FIG. 5) including

symbols

10 and 11. A first symbol of the slot may include the gap duration and the AGC duration. The gap duration may be at a first half symbol of the first symbol, the AGC duration may be at a second half symbol of the first symbol, and the first symbol may be at the beginning of the slot.

Additionally or alternatively, the sidelink UE may communicate PSFCH in a last symbol (e.g., symbol 13) of the slot. The sidelink UE may receive or transmit the PSFCH in the last symbol. Agiven symbol (e.g., symbol 12) immediately preceding the last symbol of the slot may include the gap duration and the AGC duration. The gap duration may be at a first half symbol of the given symbol, the AGC duration may be at a second half symbol of the given symbol, and the given symbol may immediately succeed the eleven consecutive symbols 1-11 of the slot.

As an example illustrated in FIG. 7, the UE 115 may shift a symbol boundary of the slot 704 by half a symbol after a beginning half symbol. The sidelink transmission may be for a PSCCH/PSSCH transmission and may be devoid of PSFCH. A first symbol of the slot 704 may have a half symbol length (e.g., half OFDM symbol period) and may include the gap duration and the AGC duration. The gap duration may be at a first half symbol of the first symbol, the AGC duration may be at a second half symbol of the first symbol, and the first symbol may be at the beginning of the slot. The sidelink transmission may be for a PSCCH/PSSCH transmission and may be devoid of PSFCH. In some instances, the sidelink UE may transmit PSCCH/PSSCH in up to 13.5 consecutive symbols (e.g., symbols 1-13 and 13’ in FIG. 7) . In some instances, the UE 115 may utilize the last half symbol 13’ of the slot 704 for a reference signal transmission. For instance, the reference signal may be a physical waveform sequence.

As an example illustrated in FIG. 8, the UE 115 may shift a symbol boundary of the slot 804 by half a symbol after a beginning half symbol. The sidelink UE may transmit PSCCH/PSSCH in a sidelink communication and/or may communicate PSFCH in a sidelink communication. If the sidelink UE transmits PSCCH/PSSCH in the slot 804, the sidelink UE may transmit PSCCH/PSSCH in up to twelve consecutive symbols (e.g., symbols 1-12 in FIG. 7) including symbols 10-12. Afirst symbol of the slot 804 may have a half symbol length (e.g., half OFDM symbol period) and may include the gap duration and the AGC duration. The gap duration may be at a first half symbol of the first symbol, the AGC duration may be at a second half symbol of the first symbol, and the first symbol may be at the beginning of the slot.

Additionally or alternatively, the sidelink UE may communicate PSFCH in a last symbol (e.g., symbol 13) of the slot. The sidelink UE may receive or transmit the PSFCH in the last symbol. A given symbol (e.g., symbol 12) immediately preceding the last symbol of the slot may have a half symbol length (e.g., half OFDM symbol period) and include the gap duration and the AGC duration. The gap duration may be at a first half symbol of the given symbol, the AGC duration may be at a second half symbol of the given symbol, and the given symbol may immediately succeed the last symbol of the slot.

As an example illustrated in FIG. 9, the UE 115 may shift a symbol boundary of the slot 904 by half a symbol after a beginning half symbol. The sidelink transmission may be for a PSCCH/PSSCH transmission and may be devoid of PSFCH. The slot 904 may include a plurality of mini-slots, each mini-slot including a first symbol and three consecutive symbols. The first symbol may have a half symbol length, and each of the three consecutive symbols may have a full symbol length. The first symbol may includes the gap duration and the AGC duration, where each of the gap duration and the AGC duration in the first symbol is a quarter of the full symbol length, and the gap duration is followed by the AGC duration in the first symbol. In some instances, the sidelink UE may transmit PSCCH/PSSCH in up to 3 consecutive symbols in each mini-slot.

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

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

The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described above can be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations. Also, as used herein, including in the claims, “or” as used in a list of items (for example, a list of items prefaced by a phrase such as “at least one of” or “one or more of” ) indicates an inclusive list such that, for example, a list of [at least one of A, B, or C] means A or B or C or AB or AC or BC or ABC (i.e., A and B and C) .

As those of some skill in this art will by now appreciate and depending on the particular application at hand, many modifications, substitutions and variations can be made in and to the materials, apparatus, configurations and methods of use of the devices of the present disclosure without departing from the spirit and scope thereof. In light of this, the scope of the present disclosure should not be limited to that of the particular embodiments illustrated and described herein, as they are merely by way of some examples thereof, but rather, should be fully commensurate with that of the claims appended hereafter and their functional equivalents.

Claims

A method of wireless communication performed by a sidelink user equipment (UE) , comprising:

determining a cyclic prefix (CP) extension length to provide an automatic gain control (AGC) duration and a gap duration for a sidelink transmission;

applying a CP extension having the CP extension length to the sidelink transmission; and

transmitting the sidelink transmission with the CP extension.
The method of claim 1, wherein transmitting the sidelink transmission includes transmitting the sidelink transmission in a slot, a first symbol of the slot including the gap duration and the AGC duration.
The method of claim 2, wherein the gap duration is at a first half symbol of the first symbol and the AGC duration is at a second half symbol of the first symbol.
The method of claim 2 or claim 3, wherein the first symbol is at the beginning of the slot.
The method of claim 2 or claim 3, wherein transmitting the sidelink transmission includes transmitting a physical sidelink shared channel (PSSCH) in a last symbol of the slot.
The method of claim 5, wherein the sidelink transmission is devoid of a physical sidelink feedback channel (PSFCH) .
The method of claim 2 or claim 3 performed by the sidelink UE, further comprising:

transmitting a second sidelink transmission including a second PSSCH in a second slot immediately preceding the first slot, wherein transmitting the second sidelink transmission includes transmitting the second PSSCH in a last symbol of the second slot, and the last symbol of the second slot is adjacent to the first symbol of the first slot.
The method of claim 2 or claim 3, wherein transmitting the sidelink transmission with the first CP extension includes transmitting a physical sidelink feedback channel (PSFCH) in a last symbol of the slot, and wherein the first symbol immediately precedes the last symbol.
The method of claim 8 performed by the sidelink UE, further comprising:

determining a second CP extension length to provide a second AGC duration and a second gap duration for a second sidelink transmission, the beginning symbol of the slot including the second AGC duration and the second gap duration; and

communicating the second sidelink transmission with the second CP extension, wherein the second CP extension is located between the second gap duration and a third symbol.
The method of claim 9, wherein communicating the second sidelink transmission includes receiving the second sidelink transmission.
The method of claim 9 performed by the sidelink UE, further comprising:

applying a second CP extension having the second CP extension length to the second sidelink transmission, wherein communicating the second sidelink transmission includes transmitting the second sidelink transmission.
The method of claim 11, wherein transmitting the second sidelink transmission with the second CP extension includes transmitting at least one of a PSCCH or a PSSCH transmission in the third symbol.
The method of claim 12, wherein transmitting the second sidelink transmission includes transmitting at least one of the PSCCH or the PSSCH transmission in a plurality of symbols including the third symbol.
The method of claim 13, wherein the plurality of symbols includes eleven consecutive symbols located between the first CP extension and the second CP extension in the slot.
The method of claim 2, wherein the slot includes a plurality of symbols including a first set of symbols and a second set of symbols, each symbol of the first set of symbols having a full symbol length, and each symbol of the second set of symbols having a half symbol length.
The method of claim 15, wherein the second set of symbols includes the first symbol, and the gap duration is at a first half symbol of the first symbol and the AGC duration is at a second half symbol of the first symbol.
The method of claim 15, wherein each of the gap duration and the AGC duration is a quarter of the full symbol length, and the gap duration is followed by the AGC duration in the first symbol.
The method of claim 15, claim 16, or claim 17, wherein the first symbol is at the beginning of the slot.
The method of claim 15, claim 16, or claim 17, wherein the first set of symbols includes thirteen consecutive symbols, and the second set of symbols includes the first symbol that precedes the thirteen consecutive symbols and further includes a second symbol that succeeds the thirteen consecutive symbols.
The method of claim 15, claim 16, or claim 17, performed by the sidelink UE, the method further comprising:

shifting a symbol boundary of the slot by half a symbol, wherein transmitting the sidelink transmission includes transmitting the sidelink transmission in accordance with the shifted symbol boundary.
The method of claim 15, claim 16, or claim 17, wherein transmitting the sidelink transmission includes transmitting a physical sidelink shared channel (PSSCH) in a last full symbol of the slot.
The method of claim 21, wherein transmitting the sidelink transmission includes transmitting the PSSCH in a last half symbol immediately succeeding the last full symbol of the slot.
The method of claim 21, wherein transmitting the sidelink transmission includes transmitting a reference signal in a last half symbol immediately succeeding the last full symbol of the slot.
The method of claim 15, claim 16, or claim 17, wherein the sidelink transmission is devoid of a physical sidelink feedback channel (PSFCH) .
The method of claim 15, claim 16, or claim 17, wherein transmitting the sidelink transmission with the first CP extension includes transmitting a physical sidelink feedback channel (PSFCH) in a last symbol of the slot, and wherein the first symbol immediately precedes the last symbol.
The method of claim 25 performed by the sidelink UE, further comprising:

determining a second CP extension length to provide a second AGC duration and a second gap duration for a second sidelink transmission, the beginning symbol of the slot including the second AGC duration and the second gap duration; and

communicating the second sidelink transmission with the second CP extension, wherein the second CP extension is located between the second gap duration and a third symbol.
The method of claim 26, wherein communicating the second sidelink transmission includes receiving the second sidelink transmission.
The method of claim 26 performed by the sidelink UE, further comprising:

applying a second CP extension having the second CP extension length to the second sidelink transmission, wherein communicating the second sidelink transmission includes transmitting the second sidelink transmission.
The method of claim 28, wherein transmitting the second sidelink transmission with the second CP extension includes transmitting at least one of a PSCCH or a PSSCH transmission in the third symbol of the first set of symbols.
The method of claim 29, wherein the first set of symbols includes twelve consecutive symbols.
The method of claim 26, wherein the beginning symbol has a half symbol length, and wherein the second gap duration is at a first half symbol of the beginning symbol and the AGC duration is at a second half symbol of the beginning symbol.
The method of claim 1, wherein transmitting the sidelink transmission includes transmitting the sidelink transmission in a first mini-slot of a plurality of mini-slots in a slot, the first mini-slot including a first symbol and a plurality of symbols, the first symbol having a half symbol length, and each symbol of the plurality of symbols having a full symbol length.
The method of claim 32, wherein the plurality of symbols includes three consecutive symbols, and the first symbol immediately precedes the plurality of symbols.
The method of claim 32, wherein the slot includes four mini-slots, and each mini-slot has a 3.5 symbol length in the slot.
The method of claim 32, wherein the first symbol includes the gap duration and the AGC duration.
The method of claim 35, wherein each of the gap duration and the AGC duration in the first symbol is a quarter of the full symbol length, and the gap duration is followed by the AGC duration in the first symbol.
The method of claim 32, claim 33, claim 34, claim 35, or claim 36, wherein transmitting the sidelink transmission includes transmitting at least one of a PSCCH or a PSSCH transmission in the plurality of symbols.
The method of claim 32, claim 33, claim 34, claim 35, or claim 36, performed by the sidelink UE, the method further comprising:

shifting a symbol boundary of the slot by half a symbol, wherein transmitting the sidelink transmission includes transmitting the sidelink transmission in accordance with the shifted symbol boundary.
The method of claim 38, wherein the slot includes a first mini-slot that immediately precedes a second mini-slot, the second mini-slot immediately precedes a third mini-slot, the third mini-slot immediately precedes a fourth mini-slot, and the first and third mini-slots are on a half symbol boundary.
The method of claim 39, wherein the second and fourth mini-slots are on a symbol boundary.
The method of claim 1, wherein the CP extension length corresponds to the AGC duration.
The method of claim 1, wherein the AGC duration is shorter than a duration of a given symbol.
The method of claim 42, wherein the AGC duration is followed by the given symbol.
The method of claim 1, wherein the CP extension length is based on a subcarrier spacing (SCS) .
The method of claim 44, wherein the SCS is 15 kilohertz (kHz) .
The method of claim 44, wherein the SCS is 30 KHz.
The method of claim 1, wherein the CP extension length is based on a capability of the sidelink UE.
The method of claim 1 performed by the sidelink UE, further comprising:

performing an LBT during the gap duration, wherein transmitting the sidelink transmission includes transmitting the sidelink transmission if the LBT is successful.
A user equipment (UE) , comprising:

a processor configured to:

determine a cyclic prefix (CP) extension length to provide an automatic gain control (AGC) duration and a gap duration for a sidelink transmission; and

apply a CP extension having the CP extension length to the sidelink transmission; and a transceiver configured to transmit the sidelink transmission with the CP extension.
The UE of claim 49, wherein the transceiver is configured to transmit the sidelink transmission in a slot, and a first symbol of the slot includes the gap duration and the AGC duration.
The UE of claim 50, wherein the gap duration is at a first half symbol of the first symbol, and the AGC duration is at a second half symbol of the first symbol.
The UE of claim 50 or claim 51, wherein the first symbol is at the beginning of the slot.
The UE of claim 50 or claim 51, wherein the transceiver is configured to transmit a physical sidelink shared channel (PSSCH) in a last symbol of the slot.
The UE of claim 53, wherein the sidelink transmission is devoid of a physical sidelink feedback channel (PSFCH) .
The UE of claim 50 or claim 51, wherein the transceiver is configured to transmit a second sidelink transmission including a second PSSCH in a second slot immediately preceding the first slot, wherein the transceiver is configured to transmit the second PSSCH in a last symbol of the second slot, and the last symbol of the second slot is adjacent to the first symbol of the first slot.
The UE of claim 50 or claim 51, wherein the transceiver is configured to transmit a physical sidelink feedback channel (PSFCH) in a last symbol of the slot, and wherein the first symbol immediately precedes the last symbol.
The UE of claim 56,

wherein the processor is configured to determine a second CP extension length to provide a second AGC duration and a second gap duration for a second sidelink transmission, and wherein the beginning symbol of the slot includes the second AGC duration and the second gap duration; and

wherein the transceiver is configured to communicate the second sidelink transmission with the second CP extension, and wherein the second CP extension is located between the second gap duration and a third symbol.
The UE of claim 57, wherein the transceiver is configured to receive the second sidelink transmission.
The UE of claim 57,

wherein the processor is configured to apply a second CP extension having the second CP extension length to the second sidelink transmission; and

wherein the transceiver is configured to transmit the second sidelink transmission.
The UE of claim 50, wherein the slot includes a plurality of symbols including a first set of symbols and a second set of symbols, each symbol of the first set of symbols has a full symbol length, and each symbol of the second set of symbols has a half symbol length.
The UE of claim 60, wherein the second set of symbols includes the first symbol, and the gap duration is at a first half symbol of the first symbol and the AGC duration is at a second half symbol of the first symbol.
The UE of claim 60, wherein each of the gap duration and the AGC duration is a quarter of the full symbol length, and the gap duration is followed by the AGC duration in the first symbol.
The UE of claim 60, claim 61, or claim 62, wherein the first symbol is at the beginning of the slot.
The UE of claim 60, claim 61, or claim 62,

wherein the processor is configured to shift a symbol boundary of the slot by half a symbol; and

wherein the transceiver is configured to transmit the sidelink transmission in accordance with the shifted symbol boundary.
The UE of claim 60, claim 61, or claim 62, wherein the transceiver is configured to transmit a physical sidelink shared channel (PSSCH) in a last full symbol of the slot.
The UE of claim 65, wherein the transceiver is configured to transmit the PSSCH in a last half symbol immediately succeeding the last full symbol of the slot.
The UE of claim 65, wherein the transceiver is configured to transmit a reference signal in a last half symbol immediately succeeding the last full symbol of the slot.
The UE of claim 60, claim 61, or claim 62, wherein the sidelink transmission is devoid of a physical sidelink feedback channel (PSFCH) .
The UE of claim 60, claim 61, or claim 62, wherein the transceiver is configured to transmit a physical sidelink feedback channel (PSFCH) in a last symbol of the slot, and wherein the first symbol immediately precedes the last symbol.
The UE of claim 69,

wherein the processor is configured to determine a second CP extension length to provide a second AGC duration and a second gap duration for a second sidelink transmission, and wherein the beginning symbol of the slot includes the second AGC duration and the second gap duration; and

wherein the transceiver is configured to communicate the second sidelink transmission with the second CP extension, and wherein the second CP extension is located between the second gap duration and a third symbol.
The UE of claim 70, wherein the transceiver is configured to receive the second sidelink transmission.
The UE of claim 70,

wherein the processor is configured to apply a second CP extension having the second CP extension length to the second sidelink transmission; and

wherein the transceiver is configured to transmit the second sidelink transmission.
The UE of claim 49, wherein the transceiver is configured to transmit the sidelink transmission in a first mini-slot of a plurality of mini-slots in a slot, the first mini-slot includes a first symbol and a plurality of symbols, the first symbol has a half symbol length, and each symbol of the plurality of symbols has a full symbol length.
The UE of claim 73, wherein the plurality of symbols includes three consecutive symbols, and the first symbol immediately precedes the plurality of symbols.
The UE of claim 73, wherein the slot includes four mini-slots, and each mini-slot has a 3.5 symbol length in the slot.
The UE of claim 73, wherein the first symbol includes the gap duration and the AGC duration.
The UE of claim 76, wherein each of the gap duration and the AGC duration in the first symbol is a quarter of the full symbol length, and the gap duration is followed by the AGC duration in the first symbol.
The UE of claim 73, claim 74, claim 75, claim 76, or claim 77, wherein the transceiver is configured to transmit at least one of a PSCCH or a PSSCH transmission in the plurality of symbols.
The UE of claim 73, claim 74, claim 75, claim 76, or claim 77,

wherein the processor is configured to shift a symbol boundary of the slot by half a symbol; and

wherein the transceiver is configured to transmit the sidelink transmission in accordance with the shifted symbol boundary.
The UE of claim 49, wherein the CP extension length corresponds to the AGC duration.
The UE of claim 49, wherein the AGC duration is shorter than a duration of a symbol.
The UE of claim 81, wherein the AGC duration is followed by the symbol.
The UE of claim 49, wherein the CP extension length is based on a subcarrier spacing (SCS) .
The UE of claim 83, wherein the SCS is 15 kilohertz (kHz) .
The UE of claim 83, wherein the SCS is 30 KHz.
The UE of claim 49, wherein the CP extension length is based on a capability of the sidelink UE.
The UE of claim 49,

wherein the processor is configured to perform an LBT during the gap duration; and

wherein the transceiver is configured transmit the sidelink transmission ifthe LBT is successful.
A non-transitory computer-readable medium having program code recorded thereon, the program code comprising:

code for causing a sidelink user equipment (UE) to determine a cyclic prefix (CP) extension length to provide an automatic gain control (AGC) duration and a gap duration for a sidelink transmission;

code for causing the sidelink UE to apply a CP extension having the CP extension length to the sidelink transmission; and

code for causing the sidelink UE to transmit the sidelink transmission with the CP extension.
The non-transitory computer-readable medium of claim 88, wherein the code for causing the sidelink UE to transmit the sidelink transmission includes code for causing the sidelink UE to transmit the sidelink transmission in a slot, wherein a first symbol of the slot includes the gap duration and the AGC duration.
The non-transitory computer-readable medium of claim 89, wherein the gap duration is at a first half symbol of the first symbol and the AGC duration is at a second half symbol of the first symbol.
The non-transitory computer-readable medium of claim 89 and 90, wherein the code for causing the sidelink UE to transmit the sidelink transmission includes code for causing the sidelink UE to transmit a physical sidelink shared channel (PSSCH) in a last symbol of the slot.
The non-transitory computer-readable medium of claim 91, wherein the sidelink transmission is devoid of a physical sidelink feedback channel (PSFCH) .
The non-transitory computer-readable medium of claim 89 and 90, wherein the code for causing the sidelink UE to transmit the sidelink transmission with the first CP extension includes code for causing the sidelink UE to transmit a physical sidelink feedback channel (PSFCH) in a last symbol of the slot, and wherein the first symbol immediately precedes the last symbol.
The non-transitory computer-readable medium of claim 89, wherein the slot includes a plurality of symbols including a first set of symbols and a second set of symbols, each symbol of the first set of symbols has a full symbol length, and each symbol of the second set of symbols has a half symbol length.
The non-transitory computer-readable medium of claim 94, wherein the second set of symbols includes the first symbol, and the gap duration is at a first half symbol of the first symbol and the AGC duration is at a second half symbol of the first symbol.
The non-transitory computer-readable medium of claim 94, wherein each of the gap duration and the AGC duration is a quarter of the full symbol length, and the gap duration is followed by the AGC duration in the first symbol.
The non-transitory computer-readable medium of claim 88, wherein the code for causing the sidelink UE to transmit the sidelink transmission includes code for causing the sidelink UE to transmit the sidelink transmission in a first mini-slot of a plurality of mini-slots in a slot, wherein the first mini-slot includes a first symbol and a plurality of symbols, the first symbol has a half symbol length, and each symbol of the plurality of symbols has a full symbol length.
The non-transitory computer-readable medium of claim 97, wherein the first symbol includes the gap duration and the AGC duration.
The non-transitory computer-readable medium of claim 98, wherein each of the gap duration and the AGC duration in the first symbol is a quarter of the full symbol length, and the gap duration is followed by the AGC duration in the first symbol.
The non-transitory computer-readable medium of claim 97, wherein the code for causing the sidelink UE to transmit the sidelink transmission includes code for causing the sidelink UE to transmit at least one of a PSCCH or a PSSCH transmission in the plurality of symbols.
A user equipment (UE) comprising:

means for determining a cyclic prefix (CP) extension length to provide an automatic gain control (AGC) duration and a gap duration for a sidelink transmission;

means for applying a CP extension having the CP extension length to the sidelink transmission; and

means for transmitting the sidelink transmission with the CP extension.
The UE of claim 101, wherein the means for transmitting the sidelink transmission with the CP extension includes means for transmitting the sidelink transmission includes transmitting the sidelink transmission in a slot, and wherein a first symbol of the slot includes the gap duration and the AGC duration.
The UE of claim 102, wherein the gap duration is at a first half symbol of the first symbol and the AGC duration is at a second half symbol of the first symbol.
The UE of claim 102 or claim 103, wherein the means for transmitting the sidelink transmission includes means for transmitting a physical sidelink shared channel (PSSCH) in a last symbol of the slot.
The UE of claim 101, wherein the means for transmitting the sidelink transmission with the CP extension includes means for transmitting a physical sidelink feedback channel (PSFCH) in a last symbol of the slot, and wherein the first symbol immediately precedes the last symbol.
The UE of claim 102, wherein the slot includes a plurality of symbols including a first set of symbols and a second set of symbols, each symbol of the first set of symbols has a full symbol length, and each symbol of the second set of symbols has a half symbol length.
The UE of claim 106, wherein the second set of symbols includes the first symbol, and the gap duration is at a first half symbol of the first symbol and the AGC duration is at a second half symbol of the first symbol.
The UE of claim 106, wherein each of the gap duration and the AGC duration is a quarter of the full symbol length, and the gap duration is followed by the AGC duration in the first symbol.
The UE of claim 101, wherein the means for transmitting the sidelink transmission with the CP extension includes means for transmitting the sidelink transmission in a first mini-slot of a plurality of mini-slots in a slot, the first mini-slot includes a first symbol and a plurality of symbols, the first symbol has a half symbol length, and each symbol of the plurality of symbols has a full symbol length.