Layer 1 channel state information feedback via second stage sidelink control information for vehicle-to-everything and sidelink communications

Abstract

The present disclosure provides wireless communication systems and methods involving communicating sidelink channel state information (CSI) from one user equipment (UE) to another UE using L1 signaling. A first UE requests a CSI report from a second UE. The first UE transmits a reference signal, which the second UE measures to determine channel characteristics. The second UE forms a CSI report that includes a rank indicator, a channel quality indicator, and possibly a precoding matrix index indicator. The second UE forms the CSI report at the PHY layer. The CSI report is included in a reserved field of a second stage sidelink control information (SCI-2). The first UE receives and processes the CSI report at the PHY layer.

Description

[0001] Cross-references to related applications

[0002] This application claims priority and benefit to U.S. Patent Application No. 17 / 383,005, filed July 22, 2021, and U.S. Provisional Patent Application No. 62 / 706,052, filed July 29, 2020, the disclosures of which are incorporated herein by reference in their entirety, as if fully set forth herein and used for all applicable purposes. Technical Field

[0003] This application relates to wireless communication systems, and more specifically to improving the transmission of side link channel state information.

[0004] introduction

[0005] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, and broadcasting. These systems can support communication with multiple users by sharing available system resources (e.g., time, frequency, and power). A wireless multiple access communication system may include multiple base stations (BSs), each supporting communication from multiple communication devices simultaneously, which may also be referred to as user equipment (UEs). The BS can communicate with the UEs in both uplink and downlink directions.

[0006] Sidelinks are introduced to allow a UE to send data to another UE without tunneling through the BS and / or associated core network. Sidelink technology has been extended to provide device-to-device (D2D) communication, vehicle-to-everything (V2X) communication, and / or cellular vehicle-to-everything (C-V2X) communication. Similarly, NR can be extended to support D2D, V2X, and / or C-V2X sidelink communication on dedicated spectrum, licensed spectrum, and / or unlicensed spectrum.

[0007] When a UE communicates via a sidelink connection, it is desirable to characterize the channel being used. To characterize the channel, one UE can send a reference signal to another UE, which measures the signal to determine the characteristics of the channel. To achieve the lowest possible latency and improved spectral efficiency, it is desirable to transmit and receive the channel characterization as quickly as possible. Summary of the Invention

[0008] The following outlines some aspects of this disclosure to provide a basic understanding of the techniques discussed. This overview is not an extensive summary of all the intended features of this disclosure, and is neither intended to identify key or essential elements of all aspects of this disclosure, nor to depict the scope of any or all aspects of this disclosure. Its sole purpose is to present some concepts of one or more aspects of this disclosure in an overview form as a prelude to the more detailed description that follows.

[0009] For example, in one aspect of this disclosure, a method of wireless communication includes transmitting a request and reference signal for channel state information (CSI) reporting from a first user equipment (UE) to a second UE. The method also includes the first UE receiving second-stage side link control information (SCI-2) from the second UE in response to the request, wherein the SCI-2 is a Layer 1 signal and includes one or more reporting fields for CSI reporting. The method further includes the first UE retrieving the CSI report from the SCI-2 at the physical layer.

[0010] In an additional aspect of this disclosure, a method of wireless communication includes receiving a request and reference signal for channel state information (CSI) from a second UE by a first user equipment (UE). The method further includes performing channel measurements by the first UE based on the reference signal. The method also includes forming second-stage side link control information (SCI-2) at the physical layer by the first UE, the SCI-2 including a CSI report based on the channel measurements. The method further includes transmitting the SCI-2 as a Layer 1 signal from the first UE to the second UE.

[0011] In an additional aspect of this disclosure, a first user equipment (UE) includes a transceiver configured to transmit a request for a CSI report and a reference signal to a second UE. The transceiver is also configured to receive an SCI-2 from the second UE in response to the request, wherein the SCI-2 is a Layer 1 signal and includes one or more reporting fields for the CSI report. The UE also includes a processor configured to extract the CSI report from the SCI-2 at the physical layer.

[0012] In an additional aspect of this disclosure, a first user equipment (UE) includes a transceiver configured to receive a request and reference signal for CSI from a second UE. The first UE also includes a processor configured to perform channel measurements based on the reference signal. The first UE further includes a processor configured to form an SCI-2 at the physical layer, the SCI-2 including a CSI report based on the channel measurements. The transceiver is also configured to transmit the SCI-2 as a Layer 1 signal to the second UE.

[0013] In an additional aspect of this disclosure, a non-transitory computer-readable medium is provided having program code recorded thereon. The program code includes code for causing a first user equipment (UE) to transmit a request for a CSI report and a reference signal to a second UE. The program code also includes code for causing the first UE to receive SCI-2 from the second UE in response to the request, wherein SCI-2 is a Layer 1 signal and includes one or more report fields for CSI reporting. The program code further includes code for causing the first UE to retrieve the CSI report from SCI-2 at the physical layer.

[0014] In an additional aspect of this disclosure, a non-transitory computer-readable medium is provided having program code recorded thereon. The program code includes code for causing a first user equipment (UE) to receive a request and reference signal for CSI from a second UE. The program code also includes code for causing the first UE to perform channel measurements based on the reference signal. The program code further includes code for causing the first UE to form a second-stage SCI-2 at the physical layer, the SCI-2 including a CSI report based on the channel measurements. The program code also includes code for causing the first UE to transmit the SCI-2 as a Layer 1 signal to the second UE.

[0015] In an additional aspect of this disclosure, a first user equipment (UE) includes components for transmitting a request for a CSI report and a reference signal to a second UE. The first UE also includes components for receiving an SCI-2 from the second UE in response to the request, wherein the SCI-2 is a Layer 1 signal and includes one or more report fields for the CSI report. The first UE further includes components for retrieving the CSI report from the SCI-2 at the physical layer.

[0016] In an additional aspect of this disclosure, a first user equipment (UE) includes components for receiving a request and reference signal for channel state information (CSI) from a second UE. The first UE also includes components for performing channel measurements based on the reference signal. The first UE further includes components for forming a Channel State Information-2 (SCI-2) at the physical layer, the SCI-2 including a CSI report based on the channel measurements. The first UE also includes components for transmitting the SCI-2 as a Layer 1 signal to the second UE.

[0017] Other aspects, features, and embodiments of the invention will become apparent to those skilled in the art after reviewing the following description of specific exemplary embodiments of the invention in conjunction with the accompanying drawings. While features of the invention may be discussed with respect to certain embodiments and the drawings below, all embodiments of the invention may 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 these features may also be used according to the various embodiments of the invention discussed herein. Similarly, while exemplary embodiments may be discussed below as device, system, or method embodiments, it should be understood that such exemplary embodiments may be implemented in various devices, systems, and methods. Attached Figure Description

[0018] Figure 1 A wireless communication network according to some aspects of this disclosure is shown.

[0019] Figure 2A wireless communication network providing side link communication according to some aspects of this disclosure is shown.

[0020] Figure 3 A sidelink communication scheme according to some aspects of this disclosure is shown.

[0021] Figure 4 This is a simplified block diagram of exemplary time slots according to some aspects of this disclosure.

[0022] Figure 5 This is a block diagram of an exemplary user equipment (UE) according to some aspects of this disclosure.

[0023] Figure 6 This is a signaling diagram of a scheme for transmitting channel state information according to some aspects of this disclosure.

[0024] Figure 7 This is a flowchart of a method for requesting and receiving channel state information according to some aspects of this disclosure.

[0025] Figure 8 This is a flowchart of a method for responding to a request for channel state information, according to some aspects of this disclosure. Detailed Implementation

[0026] The specific embodiments described below with reference to the accompanying drawings are intended as a description of various configurations, and not as representations of only configurations in which the concepts described herein can be practiced. The specific embodiments include detailed information to provide a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts can be practiced without these specific details. In some cases, well-known structures and components are shown in block diagram form to avoid obscuring these concepts.

[0027] This disclosure generally relates to wireless communication systems, also known as wireless communication networks. In various embodiments, techniques and apparatus can be used in 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, 5G or New Radio (NR) networks, and other communication networks. As described herein, the terms "network" and "system" are used interchangeably.

[0028] OFDMA networks can implement radio technologies such as evolved UTRA (E-UTRA), IEEE 802.11, IEEE 802.16, IEEE 802.20, and Flash OFDM. UTRA, E-UTRA, and GSM are part of the Universal Mobile Telecommunications System (UMTS). Specifically, Long Term Evolution (LTE) is a version of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS, and LTE are described in documents from an organization called the 3rd Generation Partnership Project (3GPP), while cdma2000 is described in documents from an organization called 3rd Generation Partnership Project 2 (3GPP2). These various radio technologies and standards are known or under development. For example, the 3rd Generation Partnership Project (3GPP) is a collaboration among telecommunications association groups aimed at defining globally applicable third-generation (3G) mobile phone specifications. 3GPP Long Term Evolution (LTE) is a 3GPP project aimed at improving the UMTS mobile phone standard. 3GPP defines specifications for next-generation mobile networks, mobile systems, and mobile devices. This disclosure relates to the evolution of wireless technologies from LTE, 4G, 5G, and NR, and covers shared access to the radio spectrum between networks using new and different sets of radio access technologies or radio air interfaces.

[0029] 5G networks take into account a variety of deployments, spectrums, services, and devices that can be implemented using a unified air interface based on OFDM. To achieve these goals, in addition to developing new radio technologies for 5G NR networks, further enhancements to LTE and LTE-A are also considered. 5G NR will be able to scale to provide: (1) coverage for massive Internet of Things (IoT) networks with ultra-high density (e.g., ~1M nodes / km). 2 (1) Ultra-low complexity (e.g., ~ tens of bits / second), ultra-low energy consumption (e.g., ~ 10+ years of battery life), and deep coverage capable of reaching challenging locations; (2) Includes mission-critical control with strong security for maintaining sensitive personal, financial, or classified information, ultra-high reliability (e.g., ~ 99.9999% reliability), ultra-low latency (e.g., ~ 1 ms), and users with a wide range of mobility or lack thereof; and (3) Includes enhanced mobile broadband, which includes extremely high capacity (e.g., ~ 10 Tbps / km). 2 Extremely high data rates (e.g., multi-Gbps rates, 100+Mbps user experience rates), and deep awareness with advanced discovery and optimization.

[0030] 5G NR can be implemented using optimized OFDM-based waveforms with scalable parameter values ​​and transmission time intervals (TTIs); it features a general, flexible framework to efficiently multiplex services and features using dynamic, low-latency Time Division Duplex (TDD) / Frequency Division Duplex (FDD) designs; and it incorporates advanced wireless technologies such as massive MIMO, robust millimeter-wave (mmWave) transmission, advanced channel coding, and device-centric mobility. The scalability of parameter values ​​and the scaling of subcarrier spacing in 5G NR can effectively address different services across different spectrums and deployments. For example, in various outdoor and macro coverage deployments of FDD / TDD implementations below 3 GHz, subcarrier spacing can occur at 15 kHz over bandwidths (BWs) such as 5, 10, and 20 MHz. For other various outdoor and small-cell coverage deployments of TDD above 3 GHz, subcarrier spacing can occur at 30 kHz over an 80 / 100 MHz BW. For various other indoor broadband implementations, using TDD on the unlicensed portion of the 5 GHz band, the subcarrier spacing can occur at 60 kHz over a 160 MHz BW. Finally, for various deployments using millimeter-wave components for TDD transmission at 28 GHz, the subcarrier spacing can occur at 120 kHz over a 500 MHz BW.

[0031] 5G NR's scalable parameter values ​​facilitate scalable TTIs for varying latency and Quality of Service (QoS) requirements. For example, shorter TTIs can be used for low latency and high reliability, while longer TTIs can be used for higher spectral efficiency. Effective multiplexing of long and short TTIs allows transmissions to begin at symbol boundaries. 5G NR also considers self-contained integrated subframe designs that incorporate UL / downlink scheduling information, data, and acknowledgments within the same subframe. These self-contained integrated subframes support communication in unlicensed or contention-based shared spectrum, and adaptive UL / downlink, which can be flexibly configured per cell to dynamically switch between UL and downlink to meet current service needs.

[0032] Various other aspects and features of this disclosure are further described below. It will be apparent that the teachings herein can be embodied in many forms, and any specific structure, function, or both disclosed herein are merely representative and not limiting. Based on the teachings herein, those skilled in the art will understand that the aspects disclosed herein can be implemented independently of any other aspects, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement an apparatus or practice a method. Furthermore, such apparatuses or practices can be implemented using other structures, functions, or structures and functions besides one or more aspects set forth herein, or such apparatuses or practices can be implemented using other structures, functions, or structures and functions besides one or more aspects set forth herein. For example, a method can 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. In addition, an aspect may include at least one element of the claims.

[0033] Sidelink communication refers to communication between user equipment (UEs) without tunneling through a base station (BS) and / or core network (e.g., via a PC5 link instead). Sidelink communication can be transmitted on the Physical Sidelink Control Channel (PSCCH) and the Physical Sidelink Shared Channel (PSSCH). In downlink (DL) communication between the BS and UE, the PSCCH is analogous to the Physical Downlink Control Channel (PDCCH), while the PSSCH is analogous to the Physical Downlink Shared Channel (PDSCH). For example, the PSCCH may carry Sidelink Control Information (SCI), while the PSSCH may carry sidelink data. Each PSCCH is associated with a corresponding PSSCH, where the SCI in the PSCCH may carry scheduling information for sidelink data transmission in the associated PSSCH. In some examples, the UE may transmit a PSSCH carrying an SCI, which may be indicated in multiple phases (e.g., two phases, three phases, etc.).

[0034] In the first-stage control (also referred to herein as SCI-1), the UE may transmit a PSSCH carrying information for resource allocation and decoding of the second-stage control. The first-stage SCI may include at least one of the following: priority, PSSCH resource allocation, resource reservation period (if enabled), PSSCH DMRS mode (if more than one mode is configured), second-stage SCI format (e.g., the size of the second SCI), resource amount of the second-stage SCI, number of PSSCH demodulation reference signal (DMRS) ports, modulation and coding scheme (MCS), etc. In the second-stage control (also referred to herein as SCI-2), the UE may transmit information on the PSSCH for decoding user data. SCI-2 may include a 16-bit L1 destination identifier (ID), an 8-bit L1 source ID, a HARQ process ID, a new data indicator (NDI), a redundancy version (RV), and additional data as described herein according to embodiments of this disclosure. Sidelink communication can also be transmitted on the Physical Sidelink Feedback Control Channel (PSFCH), which indicates an acknowledgment (ACK) or negative acknowledgment (NACK) for a previously transmitted PSSCH. Use cases for sidelink communication can include Vehicle-to-Everything (V2X), Industrial IoT (IIoT), and / or NR-lite (to name just a few).

[0035] As used herein, the term "sidelink UE" can refer to a user equipment that performs device-to-device communication or other types of communication with another user equipment without relying on any tunneling technology via a BS (e.g., gNB) and / or associated core network. As used herein, the terms "sidelink transmitting UE" and "transmitting UE" can refer to a user equipment that performs a sidelink transmitting operation. As used herein, the terms "sidelink receiving UE" and "receiving UE" can refer to a user equipment that performs a sidelink receiving operation.

[0036] The UE software protocol stack can use multiple abstraction layers. 5G-NR includes three layers, such as Layer 1, Layer 2, and Layer 3. Within these layers, sublayers can be defined. For example, Layer 3 may include the RRC layer, which is responsible for higher-level functions such as security and Quality of Service (QoS). As another example, Layer 2 may include the Media Access Control (MAC) layer and the Radio Link Control (RLC) layer. The RLC layer may be responsible for functions such as error correction. The MAC layer may be responsible for functions such as scheduling information reporting and priority processing between UEs. At Layer 1, (L1) is the Physical (PHY) layer. The PHY layer may contain transport channels (e.g., PSSCH and PSCCH). Information can be passed between abstraction layers in a defined manner. For example, the PHY layer may provide transport channels to the MAC layer, and the MAC layer may provide logical channels to the RLC layer.

[0037] When a UE receives data, the data can be passed between intermediate layers so that it can be used by higher layers. Each step in this process can increase communication latency. For example, a higher layer attempting to transmit data over a physical channel first uses a defined method to pass the data between layers, thus increasing latency. Typically, lower latency can be achieved when functions are processed at Layer 1. By performing functions at L1, it is not necessary to pass data to other abstraction layers. Additionally, headers can be added to data originating from and / or destined for higher levels. For example, the MAC layer can add a MAC header to data that can be interpreted by the MAC layer of another UE but not by the PHY layer, and is simply passed to the MAC layer.

[0038] This application describes a mechanism for transmitting sidelink channel state information using Layer 1 (L1) signaling to achieve lower latency. When a requesting UE searches for channel state information about a sidelink channel with another UE, the requesting UE sends a signal to the receiving UE. This signal may be one or more bits sent by the requesting UE to the receiving UE in an SCI-2 transmission. In conjunction with sending the request bits, the requesting UE may also send a reference signal. The receiving UE may use the reference signal to measure the channel state between the UEs (e.g., to determine the quality and / or other aspects of the channel). The receiving UE may generate a report describing certain characteristics of the channel (e.g., a Channel State Information (CSI) report) and place this report in one or more new fields in SCI-2 for transmission back to the requesting UE. As a result, instead of reporting the CSI in the MAC control element (CE), the receiving UE reports the CSI at L1.

[0039] Since the receiving UE transmits the report to the requesting UE at L1 (via SCI-2), the requesting UE also does not need to send the report to a higher layer. Instead, when the requesting UE receives the CSI report in the SCI-2 signal, it can process the report at the PHY layer (i.e., L1) instead of sending it up to another layer such as the MAC layer (and then back).

[0040] This disclosure offers several benefits. For example, using L1 signaling to transmit CSI reports helps reduce latency. This low latency, for example, may be relevant in Ultra Reliable Low Latency Communication (URLLC) use cases. By performing CSI reporting functionality at L1, there is no need to pass data to other abstraction layers (such as the MAC layer). The lower latency also improves link capacity and spectral efficiency.

[0041] Figure 1A wireless communication network 100 according to some aspects of this disclosure is illustrated. Network 100 may be a 5G network. Network 100 includes multiple base stations (BSs) 105 (labeled 105a, 105b, 105c, 105d, 105e, and 105f, respectively) and other network entities. BS 105 may be a station communicating with UE 115 and may also be referred to as an evolved Node B (eNB), a next-generation eNB (gNB), an access point, etc. Each BS 105 may provide communication coverage for a specific geographic area. In 3GPP, the term "cell" may refer to that specific geographic coverage area of ​​BS 105 and / or the BS subsystem serving that coverage area, depending on the context in which the term is used.

[0042] BS 105 can provide communication coverage for macro cells or small cells (such as pico cells or femto cells) and / or other types of cells. Macro cells typically cover a relatively large geographic area (e.g., a radius of several kilometers) and allow unrestricted access for UEs with service subscriptions from network providers. Small cells, such as pico cells, typically cover a relatively small geographic area and allow unrestricted access for UEs with service subscriptions from network providers. Small cells, such as femto cells, typically also cover a relatively small geographic area (e.g., a home) and, in addition to unrestricted access, can also provide restricted access by UEs associated with the femto cell (e.g., UEs in a Closed Subscriber Group (CSG), UEs of users in a home, etc.). A BS used for macro cells can be referred to as a macro BS. A BS used for small cells can be referred to as a small cell BS, pico BS, femto BS, or home BS. Figure 1 In the examples shown, BS 105d and 105e can be conventional macro BSs, while BS 105a-105c can be macro BSs implemented using one of three-dimensional (3D), full-dimensional (FD), or massive MIMO. BS 105a-105c can leverage their higher-dimensional MIMO capabilities to increase coverage and capacity using 3D beamforming in elevation and azimuth beamforming. BS 105f can be a small cell BS, which can be a home node or a portable access point. BS 105 can support one or more (e.g., two, three, four, etc.) cells.

[0043] Network 100 can support synchronous or asynchronous operation. For synchronous operation, BSs can have similar frame timing, and transmissions from different BSs can be approximately aligned in time. For asynchronous operation, BSs can have different frame timing, and transmissions from different BSs can be misaligned in time.

[0044] UE 115 is distributed throughout the wireless network 100, and each UE 115 can be fixed or mobile. UE 115 can also be referred to as a terminal, mobile station, subscriber unit, station, etc. UE 115 can be a cellular phone, personal digital assistant (PDA), wireless modem, wireless communication device, handheld device, tablet computer, laptop computer, cordless phone, wireless local loop (WLL) station, etc. In one aspect, UE 115 can be a device including a Universal Integrated Circuit Card (UICC). In another aspect, UE 115 can be a device without a UICC. In some aspects, UE 115 without a UICC can also be referred to as an IoT device or Internet of Things (IoE) device. UE 115a-115d are examples of mobile smartphone-type devices accessing network 100. UE 115 can also be a machine specifically configured for connecting communications, including Machine Type Communication (MTC), Enhanced MTC (eMTC), Narrowband IoT (NB-IoT), etc. UE 115e-115h are examples of various machines configured for accessing communications within network 100. UE 115i-115k is an example of a vehicle equipped with wireless communication equipment configured to access network 100 for communication. UE 115 can communicate with any type of BS, whether macro BS, small cell BS, etc. Figure 1 In this context, a lightning bolt (e.g., a communication link) indicates radio transmissions between UE 115 and serving BS 105 (which is a BS designated to serve UE 115 on the downlink (DL) and / or uplink (UL), desired transmissions between BSs, backhaul transmissions between BSs, or sidelink transmissions between UE 115 (such as and including embodiments according to this disclosure).

[0045] In operation, BS 105a-105c can use 3D beamforming and cooperative spatial technologies such as Cooperative Multipoint (CoMP) or Multi-Connection to serve UE 115a and 115b. Macro BS 105d can perform backhaul communications with BS 105a-105c and with smaller cells such as BS 105f. Macro BS 105d can also transmit multicast services subscribed to and received by UE 115c and 115d. Such multicast services may include mobile TV or streaming video, or may include other services for providing community information, such as weather emergencies or alerts, such as Amber Alerts or Grey Alerts.

[0046] BS 105 can also communicate with the core network. The core network can provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. At least some of BS 105 (e.g., examples of gNBs or Access Node Controllers (ANCs)) can connect to the core network via backhaul links (e.g., NG-C, NG-U, etc.) and can perform radio configuration and scheduling to communicate with UE 115. In various examples, BS 105 can communicate with each other directly or indirectly (e.g., via the core network) on backhaul links (e.g., X1, X2, etc.), which can be wired or wireless communication links.

[0047] Network 100 can also support mission-critical communication with ultra-reliable and redundant links for mission-critical devices such as UE 115e, which may be an unmanned aerial vehicle. Redundant communication links with UE 115e may include links from macro BSs 105d and 105e, and links from small cell BS 105f. Other machine-type devices such as UE 115f (e.g., a thermometer), UE 115g (e.g., a smart meter), and UE 115h (e.g., a wearable device) can communicate directly with BSs such as small cell BS 105f and macro BS 105e via network 100, or in a multi-step configuration by communicating with another user device that relays its information to the network (e.g., UE 115f relays temperature measurement information to smart meter UE 115g, and then the temperature measurement information is reported to the network via small cell BS 105f). Network 100 can also provide additional network efficiency through dynamic, low-latency TDD / FDD communications (such as V2V, V2X, C-V2X communications between UE 115i, 115j, or 115k and other UE 115, and / or vehicle-to-infrastructure (V2I) communications between UE 115i, 115j, or 115k and BS 105 (e.g., PC5, etc.)).

[0048] In some implementations, network 100 utilizes OFDM-based waveforms for communication. An OFDM-based system can divide the system BW into multiple (K) orthogonal subcarriers, which are also commonly referred to as subcarriers, tones, frequency bands, etc. Each subcarrier can be modulated with data. In some cases, the subcarrier spacing between adjacent subcarriers can be fixed, and the total number of subcarriers (K) can depend on the system BW. The system BW can also be divided into subbands. In other cases, the subcarrier spacing and / or the duration of the time interval (TTI) can be scalable.

[0049] In some respects, BS 105 can allocate or schedule transmission resources (e.g., in the form of time-frequency resource elements (REs)) for downlink (DL) and uplink (UL) transmissions in network 100. DL refers to the transmission direction from BS 105 to UE 115, while UL refers to the transmission direction from UE 115 to BS 105. Communication can be in the form of radio frames. Radio frames can be divided into multiple subframes or time slots, for example, approximately 10. Each time slot can also be divided into micro-time slots. In FDD mode, simultaneous UL and DL transmissions can occur in different frequency bands. For example, each subframe includes UL subframes in the UL band and DL subframes in the DL band. In TDD mode, UL and DL transmissions occur using the same frequency band at different time periods. For example, a subset of subframes (e.g., DL subframes) in a radio frame can be used for DL ​​transmissions, while another subset of subframes (e.g., UL subframes) in a radio frame can be used for UL transmissions.

[0050] DL subframes and UL subframes can be further divided into several regions. For example, each DL or UL subframe can have a predefined region for transmitting reference signals, control information, and data. Reference signals are predetermined signals that facilitate communication between BS 105 and UE 115. For example, reference signals can have a specific pilot pattern or structure, where pilot tones can span an operating BW or frequency band, with each pilot tone located at a predefined time and predefined frequency. For example, BS 105 can transmit cell-specific reference signals (CRS) and / or channel state information-reference signals (CSI-RS) to enable UE 115 to estimate the DL channel. Similarly, UE 115 can transmit sounding reference signals (SRS) to enable BS 105 to estimate the UL channel. Control information can include resource allocation and protocol control. Data can include protocol data and / or operational data. In some aspects, BS 105 and UE 115 can communicate using self-contained subframes. A self-contained subframe can include a portion for DL ​​communication and a portion for UL communication. A self-contained subframe can be DL-centric or UL-centric. The duration of the DL center subframe used for DL ​​communication can be longer than the duration used for UL communication. The duration of the UL center subframe used for UL communication can be longer than the duration used for DL ​​communication.

[0051] In some respects, network 100 may be an NR network deployed on licensed spectrum. BS 105 may transmit synchronization signals (e.g., PSS and SSS) within network 100 to facilitate synchronization. BS 105 may broadcast system information associated with network 100 (e.g., including the Master Information Block (MIB), remaining minimum system information (e.g., RMSI), and other system information (OSI)) to facilitate initial network access. In some cases, BS 105 may broadcast PSS, SSS, and / or MIB in the form of a Synchronization Signal Block (SSB) on the Physical Broadcast Channel (PBCH), and may broadcast RMSI and / or OSI on the Physical Downlink Shared Channel (e.g., PDSCH).

[0052] In some respects, UE 115 attempting to access network 100 can perform an initial cell search by detecting the PSS from BS 105. The PSS can provide periodically timed synchronization and can indicate a physical layer identification value. UE 115 can then receive the SSS. The SSS can provide radio frame synchronization and can provide a cell identification value, which can be combined with a physical layer identification value to identify the cell. The PSS and SSS can be located in the center portion of the carrier or at any suitable frequency within the carrier.

[0053] After receiving the PSS and SSS, UE 115 can receive the MIB. The MIB may include system information for initial network access and scheduling information for RMSI and / or OSI. After decoding the MIB, UE 115 can receive the RMSI and / or OSI. The RMSI and / or OSI may include radio resource control (RRC) information related to the Random Access Channel (RACH) procedure, paging, control resource set (CORESET) for monitoring the Physical Downlink Control Channel (PDCCH), Physical UL Control Channel (PUCCH), Physical UL Shared Channel (PUSCH), power control, and SRS.

[0054] After obtaining the MIB, RMSI, and / or OSI, UE 115 can perform a random access procedure to establish a connection with BS 105. In some examples, the random access procedure can be a four-step random access procedure. For example, UE 115 can transmit a random access preamble, and BS 105 can respond with a random access response. The random access response (RAR) may include a detected random access preamble identifier (ID) corresponding to the random access preamble, timing advance (TA) information, UL grant, temporary cell radio network temporary identifier (C-RNTI), and / or backoff indicator. Upon receiving the random access response, UE 115 can transmit a connection request to BS 105, and BS 105 can respond with a connection response. The connection response may indicate contention resolution. In some examples, the random access preamble, RAR, connection request, and connection response may be referred to as message 1 (MSG1), message 2 (MSG2), message 3 (MSG3), and message 4 (MSG4), respectively. In some examples, the random access procedure can be a two-step random access procedure, where UE 115 can transmit the random access preamble and connection request in a single transmission, and BS105 can respond by transmitting the random access response and connection response in a single transmission.

[0055] After the connection is established, UE 115 and BS 105 can enter the normal operation phase, during which they can exchange operational data. For example, BS 105 can schedule UE 115 for UL and / or DL ​​communication. BS 105 can transmit UL and / or DL ​​scheduling authorization to UE 115 via PDCCH. The scheduling authorization can be transmitted in the form of DL control information (DCI). BS 105 can transmit DL communication signals (e.g., carrying data) to UE 115 via PDSCH based on the DL scheduling authorization. UE 115 can transmit UL communication signals to BS 105 via PUSCH and / or PUCCH based on the UL scheduling authorization.

[0056] In some respects, BS 105 can use HARQ technology to communicate with UE 115 to improve communication reliability, such as providing URLLC services. BS 105 can schedule UE 115 for PDSCH communication by transmitting DL grants in the PDCCH. BS 105 can transmit DL data packets to UE 115 according to the schedule in the PDSCH. DL data packets can be transmitted in transport blocks (TBs). If UE 115 successfully receives DL data packets, UE 115 can transmit a HARQ ACK to BS 105. Conversely, if UE 115 fails to successfully receive the DL transmission, UE 115 can transmit a HARQ NACK to BS 105. When a HARQ NACK is received from UE 115, BS 105 can retransmit the DL data packets to UE 115. The retransmission may include the same DL data encoding version as the initial transmission. Alternatively, the retransmission may include a different DL data encoding version than the initial transmission. UE 115 can apply soft combining to combine encoded data received from the initial transmission and retransmissions for decoding. BS 105 and UE 115 can also apply HARQ to UL communications using a mechanism substantially similar to DL HARQ.

[0057] In some aspects, network 100 can operate on a system BW or a component carrier (CC) BW. Network 100 can divide the system BW into multiple BWPs (e.g., portions). BS 105 can dynamically allocate UE 115 to operate on a particular BWP (e.g., a portion of the system BW). The allocated BWP can be referred to as the active BWP. UE 115 can monitor the active BWP in response to signaling information from BS 105. BS 105 can schedule UE 115 for UL or DL ​​communication within the active BWP. In some aspects, BS 105 can allocate a pair of BWPs within a CC to UE 115 for UL and DL communication. For example, a BWP pair may include one BWP for UL communication and one BWP for DL ​​communication.

[0058] In some respects, network 100 can operate on a shared channel, which may include a shared frequency band and / or an unlicensed frequency band. For example, network 100 may be an NR-U network operating on an unlicensed frequency band. In such respects, BS 105 and UE 115 may be operated by multiple network operating entities. To avoid collisions, BS 105 and UE 115 may employ a Listen-Before-Speak (LBT) procedure to monitor transmission opportunities (TXOPs) in the shared channel. TXOPs may also be referred to as COTs (e.g., Channel Occupancy Time). For example, a transmitting node (e.g., BS 105 or UE 115) may perform an LBT before transmitting in the channel. When the LBT passes, the transmitting node may continue transmitting. When the LBT fails, the transmitting node may suppress transmission in the channel.

[0059] In some respects, network 100 can support independent sidelink communication between UEs 115 on a shared radio frequency band. NR supports multiple Radio Resource Allocation (RRA) modes for sidelinks on licensed spectrum, including Mode 1 RRA and Mode 2 RRA. Mode 1 RRA supports a network-controlled RRA that can be used for sidelink communication within coverage. Significant base station involvement is required for this mode, and it is generally operable when the sidelink UE 115 is within the coverage area of ​​serving BS 105, but is not necessary for sidelinks outside coverage. Mode 2 RRA supports an autonomous RRA that can be used for sidelink UEs 115 outside coverage or for sidelink UEs 115 in partially covered areas.

[0060] Alternatively, the standalone system may include a sidelink UE 115 designated as the anchor UE (e.g., anchor node). The anchor UE 115 can autonomously (e.g., independently of any cell and / or associated core network) initiate sidelink operations with one or more client UEs 115. Therefore, the anchor UE 115 can advertise system parameters for operation for each client UE 115 (e.g., information associated with the sidelink master information block (SL-MIB), residual minimum system information (RMSI), primary synchronization signal (PSS), secondary synchronization signal (SSS), etc.), and the anchor UE 115 can provide a corresponding radio resource control (RRC) configuration for the corresponding client UE 115. For example, the anchor UE 115 can provide a first RRC configuration to a first client UE 115 and a different second RRC configuration to a second client UE 115. Furthermore, although the anchored UE 115 can connect to the client UE using either Mode 1 RRA or Mode 2 RRA, the signaling received by the client UE 115 can remain the same between the two modes.

[0061] Regardless of the specific sidelink configuration, the sidelink UE 115 (e.g., Figure 1 UEs 115 and 115d, and / or UEs 115f and 115g, can periodically or non-periodically seek information about the channel state between sidelink UEs 115. According to embodiments of this disclosure, when a sidelink UE 115 requests channel information such as CSI from another sidelink UE 115, the responding sidelink UE 115 can return the channel information as an L1 signal (e.g., instead of L2 or others at the MAC layer) via the PHY layer within a field in the SCI-2 modified / assigned for that use. The receiving sidelink UE 115 can process the information at the PHY layer and the results.

[0062] Figure 2 An example of a wireless communication network 200 providing side-link communication according to embodiments of the present disclosure is shown. Network 200 may correspond to at least a portion of network 100. For the purpose of simplifying the discussion, Figure 2 A BS 205 and six UEs 215 (shown as 215a1, 215a2, 215a3, 215b1, 215b2, and 215b3) are illustrated; however, it should be understood that embodiments of this disclosure can be scaled to any suitable number of UEs 215 and / or BS 205. BS 205 and UE 215 can be similar to BS 105 and UE 115, respectively. BS 205 and UE 215 can share the same radio frequency band (or at least its sub-band) for communication. In some cases, the radio frequency band can be a 2.4 GHz unlicensed band, a 5 GHz unlicensed band, or a 6 GHz unlicensed band (or some other band, such as FR2). Typically, the shared radio frequency band can be any suitable frequency.

[0063] BS 205 and UEs 215a1-215a3 can be operated by a first network operating entity. UEs 215b1-215b3 can be operated by a second network operating entity. In some respects, the first network operating entity can utilize the same RAT as the second network operating entity. For example, BS 205 and UEs 215a1-215a3 of the first network operating entity and UEs 215b1-215b3 of the second network operating entity are NR-U devices. In other respects, the first network operating entity can utilize a different RAT than the second network operating entity. For example, BS 205 and UEs 215a1-215a3 of the first network operating entity can utilize NR-U technology, while UEs 215b1-215b3 of the second network operating entity can utilize WiFi or LAA technology.

[0064] In network 200, some of UEs 215a1-215a3 and / or UEs 215b1-215b3 can communicate with each other in peer-to-peer communication. For example, UE 215a1 can communicate with UE 215a2 on sidelink 252, UE 215a1 can communicate with UE 215a3 on another sidelink 251, UE 215b1 can communicate with UE 215b2 on yet another sidelink 254, and UE 215b1 can communicate with UE 215b3 on sidelink 256. Sidelinks 251, 252, 254, and 256 can be unicast bidirectional links. Some UEs 215 can also communicate with BS 205 in the UL direction and / or DL ​​direction via communication link 253. For example, UEs 215a1 and 215a3 are located within the coverage area 210 of BS 205 and therefore can communicate with BS 205. UE215a2 is located outside coverage area 210 and therefore may not communicate directly with BS 205. In some cases, UE 215a1 can operate as a relay for UE 215a2 to reach BS 205. As an example, some UE 215s may be associated with a vehicle (e.g., similar to UE 115i-k), and communications on sidelinks 251, 252, 254, and 256 may be C-V2X communications. C-V2X communications can refer to communications between the vehicle and any other wireless communication device in the cellular network. This is merely exemplary, as sidelinks can be between various UE types and any type of communication.

[0065] Similar to Figure 1 Networks 100 and 200 can support sidelink communication between UEs 215, including one or more modes supported by BS 205, and / or one or more independent modes that do not require BS 205 support. As part of the sidelink communication, a sidelink UE such as 215b1 (as an example only) can seek channel state information from another sidelink UE such as 215b2 in this example. This seeking can be done intermittently. As a result, UE 215b1 can transmit a request for channel state information to UE 215b2 (e.g., by declaring one or more bits in an SCI-2 message to UE 215b2) along with a reference signal. UE 215b2 can measure the channel based on the reference signal (triggered by the request) and generate a channel state information report.

[0066] UE 215b2 can place this information in one or more CSI report fields within CSI-2 for transmission back to UE 215b1. As a result, UE 215b2 can transmit this report as part of L1 signaling instead of as part of the PSSCH payload in one or more MAC-CEs. UE 215b1 can receive the report as L1 signaling and process the information at the PHY layer, instead of having to pass it to any upper layer.

[0067] Figure 3 A sidelink communication scheme 300 according to some aspects of this disclosure is illustrated. Scheme 300 can be adopted by UEs such as UE 115 and / or 215 in networks such as networks 100 and / or 200. Specifically, according to embodiments of this disclosure, a sidelink UE can adopt scheme 300 to participate in sidelink communication on a shared radio frequency band (e.g., in shared spectrum or unlicensed spectrum), including transmitting channel state information via L1 signaling. Figure 3 In the diagram, the x-axis represents time in arbitrary units, and the y-axis represents frequency in arbitrary units.

[0068] In scheme 300, the shared radio frequency band 301 is divided into multiple sub-channels or frequency sub-bands 302 (denoted as 302) in terms of frequency. S0 302 S1 302 S2 ... and is temporally divided into multiple sidelink time resources 304 (denoted as 304a, 304b, 304c, 304d...) for sidelink communication. For example, the range of sidelink time resources 304 can be from time slots or micro-time slots to one or more frames. Band 301 can be at any suitable frequency (e.g., approximately 2.4 GHz, 5 GHz, or 6 GHz, mmW range, etc.). Band 301 can have any suitable BW and can be divided into any suitable number of frequency subbands 302. The number of frequency subbands 302 can depend on the sidelink communication BW requirements. In one example, band 301 is an unlicensed band at 2.4 GHz and can have a bandwidth of approximately 80 MHz, which is divided into approximately 15 5 MHz frequency subbands 302.

[0069] Sidelink UEs (e.g., UE 115 and / or 215) may be equipped with a wideband receiver and a narrowband transmitter. For example, the UE may utilize the narrowband transmitter to access frequency subband 302. S2 This is to enable sidelink transmission using sidelink time resource 304. Sidelink time resource 304 can be repeated in each frequency subband 302. In some cases, such as... Figure 3Frequency gaps or guard bands may exist between adjacent frequency sub-bands 302 to mitigate interference between adjacent frequency bands. Therefore, multiple sidelink data can be transmitted simultaneously in different frequency sub-bands 302 (e.g., FDM). Sidelink time resources 304 can also be time-repeated. For example, sidelink time resources 304 can be used to transmit frequency sub-bands 302... S2 It is divided into multiple frames in time.

[0070] Sidelink time resources 304 include sidelink resources 306 in each frequency subband 302. Sidelink resources 306 can have a structure substantially similar to NR sidelink resources. For example, sidelink resource 306 can include multiple resource elements (REs), where each RE spans one symbol in time and one subcarrier in frequency. For example, sidelink resource 306 can span subcarriers included in subband 302 and symbols included in sidelink time resources 304. In some cases, sidelink resource 306 can have a duration between approximately 1 millisecond (ms) and approximately 20 ms. Each sidelink resource 306 can include PSCCH 310 and PSSCH 320. PSCCH 310 and PSSCH 320 can be multiplexed in time and / or frequency. Figure 3 In the example shown, for each sidelink resource 306, PSCCH 310 is located during the start symbol (e.g., about 1 symbol or about 2 symbols) of sidelink resource 306 and occupies a portion of the corresponding frequency subband 302, while PSSCH 320 occupies the remaining time-frequency resources in sidelink resource 306. Further, as shown, PSCCH 310 may not occupy all the frequency bands / subbands, but only a portion. This means that PSSCH 320 may also occupy a portion of the frequency band / subband in one or more first symbols (such as time slots) of a time frame. In some cases, sidelink resource 306 may also include a Physical Sidelink Feedback Channel (PSFCH), for example, the PSFCH is located during the end symbol of sidelink resource 306, such as... Figure 4 As shown. Typically, PSCCH 310, PSSCH 320 and / or PSFCH can be multiplexed within sidelink resource 306 in any suitable configuration.

[0071] In some aspects, scheme 300 is used for synchronizing sidelink communication. In other words, the sidelink UEs are time-synchronized and aligned according to symbol boundaries and sidelink resource boundaries (e.g., the start time of sidelink time resource 304). The sidelink UEs can perform synchronization in various forms, such as based on sidelink SSBs received from the sidelink UE and / or NR-U SSBs received from the BS (e.g., BS 105 and / or 205) when within the coverage area of ​​the BS. In some aspects, for example, the sidelink UEs can be pre-configured using resource pool 308 in band 301. Resource pool 308 may include multiple sidelink resources 306.

[0072] Figure 4 This is a simplified block diagram of an exemplary side link resource slot 400 that can be used to transmit requests for Channel State Information (CSI) reports or the CSI reports themselves, according to some aspects of this disclosure. The side link resource slot 400 can be, for example, as described above. Figure 3 The example of side link time resource 304 described herein. For example, side link time resource 304 may include multiple symbols and span frequency subband 302 ( Figure 3 ). Figure 4 The frequency subband 302 in the context may include multiple subcarriers.

[0073] Sidelink resource slot 400 includes a PSCCH containing SCI-1 message 402 (e.g., Figure 3 PSCCH 310) and PSSCH (e.g., Figure 3 The PSSCH 320 may include an SCI-2 message 404, a PSSCH payload 406, and a reference signal (RS) 408. However, not all described sidelink resource channels and / or fields may be necessary, and one or more embodiments may include additional channels and / or fields not shown in the figures. Furthermore, the arrangement and type of sidelink resource channels and / or fields may be changed without departing from the scope of the claims set forth herein. Additional, different, or fewer channels and / or fields may be provided.

[0074] SCI messages (e.g., SCI-1 402 and SCI-2 404) can be used to convey control information for sidelink communication. SCIs can inform client UEs (e.g., UE 115 or 215) of resource reservation intervals, frequency positions for initial transmissions and retransmissions, time gaps between initial transmissions and retransmissions, and modulation and coding schemes (MCS) for modulating data transmitted on PSSCH 320. In some embodiments, an SCI may include a frequency hopping flag field, resource block allocation and frequency hopping resource allocation fields, a time resource mode field, an MCS field, a timing advance field and / or a β offset field, and a group destination identifier field. SCIs may include other additional fields suitable for supporting control signaling (such as for V2X). The time resource mode field can provide time-domain resource allocation for the data channel (e.g., PSSCH 320), particularly potential symbols for PSSCH transmission. The MCS field can provide the MCS for PSSCH 320, which can be autonomously selected. The timing advance field and / or β offset field can provide sidelink time adjustment. Furthermore, in some embodiments, the SCI may include bits representing a request for CSI.

[0075] In some aspects, SCI can be processed using transport channel coding to generate SCI message transport blocks, followed by physical channel coding to generate corresponding PSCCH blocks. The PSCCH blocks are carried on the corresponding symbols for transmission. UE 215 can receive one or more resource blocks on the corresponding symbols to recover control signaling information and can extract data channel allocation and transmission configuration (e.g.). Further, as described above, SCI can be implemented in PSCCH 310 and PSSCH 320 (…). Figure 3 The transmission is done in stages.

[0076] For example, PSCCH 310 can be used to carry the first-stage SCI (SCI-1) 402. PSSCH 320 can be used to carry the second-stage SCI (SCI-2) 404. In some embodiments, when requesting UE 215 to use PSSCH 320 ( Figure 3 When transmitting SCI-2404 on the receiving UE 215, SCI-2404 may include an indication (e.g., one or more bits set as flags or other indicators) representing a request to perform channel measurements on the receiving UE 215 and return a channel report (also referred to as a CSI report in this document for simplicity), as described in more detail below. PSSCH 320 ( Figure 3 User data can also be carried in the PSSCH payload 406. The PSSCH 320 may also include a reference signal 408, such as CSI-RS in some examples.

[0077] As another example, this time from the perspective of receiving UE 215 (from the requesting UE 215, such as...) Figure 2 In the case of UE 215b2 (which receives a request from UE 215b1), SCI-1 401 can again be used to carry information about SCI-2 404. When receiving UE 215 generates a CSI report in response to a CSI request from requesting UE 215, receiving UE 215 can place information into one or more CSI report fields added to SCI-2 404 according to embodiments of this disclosure. By including the CSI report in SCI-2 404, rather than as part of PSSCH payload 406, receiving UE 215 reduces latency by processing at L1 rather than at a higher layer (such as the MAC layer). Similarly, requesting UE 215 receiving a CSI report via SCI-2 can process the CSI report information at L1 rather than a higher layer.

[0078] Figure 5 This is a block diagram of an exemplary UE 500 (e.g., a sidelink UE that transmits requests, receives requests / transmits reports, and / or receives reports in SCI-2) based on some aspects of this disclosure. UE 500 can be the above-described... Figure 1 In the network 100 discussed in the article, UE 115 or above are in Figure 2 The UE 215 discussed herein. As shown in the figure, the UE 500 may include a processor 502, a memory 504, a sidelink communication module 508, a transceiver 510 including a modem subsystem 512 and a radio frequency (RF) unit 514, and one or more antennas 516. These components may communicate with each other directly or indirectly via one or more buses.

[0079] Processor 502 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. Processor 502 may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, a combination of one or more microprocessors and a DSP core, or any other such configuration.

[0080] Memory 504 may include cache memory (e.g., cache memory of processor 502), random access memory (RAM), magnetoresistive RAM (MRAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, solid-state memory devices, hard disk drives, other forms of volatile and non-volatile memory, or combinations of different types of memory. In one aspect, memory 504 includes a non-transitory computer-readable medium. Memory 504 may store or has recorded instructions 506 thereon. Instructions 506 may include, when executed by processor 502, cause processor 502 to perform, various aspects thereof incorporated herein by reference (e.g., ...). Figure 1-4 (and aspects of 7-15) Instructions relating to the operations described in UE 115. Instruction 506 may also be referred to as program code. Program code can be used to cause a wireless communication device to perform these operations, for example by causing one or more processors (such as processor 502) to control or command the wireless communication device to perform these operations. The terms “instruction” and “code” should be interpreted broadly to include any type of computer-readable statement. For example, the terms “instruction” and “code” can refer to one or more programs, routines, subroutines, functions, procedures, etc. “Instruction” and “code” can include a single computer-readable statement or multiple computer-readable statements.

[0081] The sidelink communication module 508 can be implemented via hardware, software, or a combination thereof. For example, the sidelink communication module 508 can be implemented as a processor, circuitry, and / or instructions 506 stored in memory 504 and executed by processor 502. In some cases, the sidelink communication module 508 can be integrated into the modem subsystem 512. For example, the sidelink communication module 508 can be implemented by a combination of software components (e.g., executed by a DSP or general-purpose processor) and hardware components (e.g., logic gates and circuitry) within the modem subsystem 512.

[0082] The sidelink communication module 508 can be used in various aspects of this disclosure, such as Figure 1-4Regarding aspects 6-8: When UE 500 operates in the requesting role, UE 500 can use aspects of the sidelink communication module 508, while when UE 500 operates in the receiving / responding role, UE 500 can use other aspects of the sidelink communication module 508. For example, when UE 500 is in the requesting role, the sidelink communication module 508 can cause UE 500 to transmit a request for a CSI report to receiving UE 500. For example, a request for a CSI report can be transmitted in SCI-2. The sidelink communication module 508 can also cause UE 500 to transmit a reference signal to receiving UE 500 in conjunction with a CSI report request. As part of the requesting role, the sidelink communication module 508 can also receive a CSI report from receiving UE 500 in response to a request for a CSI report. This can be received as part of an SCI-2 message, for example via one or more fields added to the SCI-2 to accommodate the CSI report (including, for example, the Rank Indicator (RI), Channel Quality Indicator (CQI), and / or Precoding Matrix Index (PMI) indicator). The sidelink communication module 508 can assist in retrieving the CSI report at L1 (i.e., the message can be interpreted without sending it to the MAC layer and removing the MAC header). Details regarding SCI-1 and SCI-2 are included in the context of the remaining figures.

[0083] As described above, the sidelink communication module 508 can also be used in conjunction with the UE 500 that receives a request for a CSI report. In this case, the sidelink communication module 508 can receive the request to provide a CSI report. Thus, the sidelink communication module 508 can receive a reference signal such as CSI-RS. The UE 500 uses the reference signal to measure channel quality and reports it as a CQI. The sidelink communication module 508 can generate a CSI report with a CQI. The CSI report can include multiple components, including the CQI. For example, the sidelink communication module can include a rank indicator in the CSI report. According to some aspects of this disclosure, the rank indicator can be a single bit, although it can be other sizes. According to some aspects of this disclosure, the CQI length can be 4 bits, although it can be other lengths. Additionally, the sidelink communication module 508 can include a PMI indicator in the CSI report.

[0084] Once the CSI report is created, the sidelink communication module 508 can include the CSI report in the SCI-2 message sent to the requesting UE. This SCI-2 message is an L1 signal because it is generated at the L1 (PHY) layer. The SCI-2 message includes several fields that are identifiable by the UE receiving the message. In addition to identification fields such as HARQ process ID, new data indicator, redundancy version, source ID, destination ID, and CSI request (if included), the SCI-2 may also include new fields for all individual elements of the CSI report. These fields may, for example, be 5 or 6 bits in size. Alternatively, the RI, CQI, and PMI indicators may each be in their own new fields in the SCI-2, such as a 1-bit field for the RI, a field ranging from 1 to 6 bits for the PMI (e.g., depending on one or more higher-layer parameters), and a 4-bit field for the CQI. Alternatively, two of these three fields may be in the same field, while the third is included in its own field. Finally, in addition to the RI indicator, CQI indicator, and PMI indicator, CSI reports may include other information.

[0085] As shown, transceiver 510 may include modem subsystem 512 and RF unit 514. Transceiver 510 may be configured to communicate bidirectionally with other devices such as BS 105. Modem subsystem 512 may be configured to modulate and / or encode data from memory 504 and / or sidelink communication module 508 according to modulation and coding schemes (MCS) (e.g., low-density parity-check (LDPC) coding scheme, turbo coding scheme, convolutional coding scheme, polarity coding scheme, digital beamforming scheme, etc.). RF unit 514 may be configured to process (e.g., perform analog-to-digital conversion or digital-to-analog conversion, etc.) modulated / encoded data (e.g., SCI, sidelink data, synchronization signal, SSB, uplink data, etc.) from modem subsystem 512 (on outgoing transmission) or from another source such as UE 115 or BS 105. RF unit 514 may also be configured to perform analog beamforming in conjunction with digital beamforming. Although the modem subsystem 512 and RF unit 514 are shown as being integrated together in transceiver 510, they can be separate devices coupled together at UE 500 to enable UE 500 to communicate with other devices.

[0086] In order to include a CSI report in the SCI-2 from the receiving UE 500 to the requesting UE 500, the RF unit 514 (of the receiving UE 500 that will transmit the CSI report) is configured to transmit additional information in at least two ways. In one aspect of this disclosure, the SCI-2 transmitted by the RF unit 514 occupies the same number of resource elements as another SCI-2 without a CSI report. This can be achieved, for example, through a higher coding rate. Alternatively, the RF unit 514 may use more resource elements than the SCI-2 without a CSI report to transmit the SCI-2 containing the CSI report.

[0087] RF unit 514 can provide modulated and / or processed data, such as data packets (or, more generally, data messages containing one or more data packets and other information), to antenna 516 for transmission to one or more other devices. RF unit 514 can process the modulated and / or processed data and generate a corresponding time-domain waveform using SC-FDMA modulation before transmission via antenna 516. In other cases, RF unit 514 can utilize OFDM modulation to generate the time-domain waveform. Antenna 516 can also receive data messages transmitted from other devices. Antenna 516 can provide the received data messages for processing and / or demodulation at transceiver 510. Transceiver 510 can provide demodulated and decoded data (e.g., sidelink configuration, SCI, sidelink data, SCI reservation collision information, synchronization signals, SSB, etc.) to sidelink communication module 508 for processing. Antenna 516 can include multiple antennas of similar or different designs to maintain multiple transmission links. RF unit 514 can configure antenna 516. In some aspects, RF unit 514 may include various RF components, such as a local oscillator (LO), an analog filter, and / or a mixer. The LO and mixer may be configured based on a specific channel center frequency. The analog filter may be configured to have a specific passband depending on the channel bandwidth (BW). The RF components may be configured to operate in various power modes (e.g., normal power mode, low power mode, power-down mode) and may switch between different power modes according to the transmission and / or reception requirements at UE 500 and / or the anchored UE.

[0088] In one aspect, UE 500 may include multiple transceivers 510 implementing different RATs (e.g., NR and LTE). In another aspect, UE 500 may include a single transceiver 510 implementing multiple RATs (e.g., NR and LTE). In yet another aspect, transceiver 510 may include various components, wherein different combinations of components can implement different RATs.

[0089] Figure 6This is a signaling diagram illustrating a communication process 600 according to some embodiments of the present disclosure. Process 600 can be implemented between two UEs (e.g., UEs 115a and 115b, UEs 115j and 115k, UEs 215b1 and 215b2, or 215a1 and 215a2, or two UEs 500). Figure 6 In the illustration, the first device 602 can be an example of requesting UE 500, while the second device 604 can be an example of receiving UE 500. Process 600 can be performed in accordance with [reference to...]. Figure 3 and Figure 4 The structures discussed are 300 and 400 and / or refer to below respectively. Figure 7 and Figure 8 The methods discussed are similar to those in 700 and 800.

[0090] At action 606, the first device 602 sends a request for a CSI report (e.g., an aperiodic request) to the second device 604. This request may be sent from the first device 602 to the second device 604 as part of an SCI-2 message carried by the PSSCH. The SCI-2 may include bits that trigger the generation of the CSI report. Alternatively, the request may take other forms, such as a message included in the PSCCH, or as part of the PSSCH data payload.

[0091] At action 608, the first device 602 sends a reference signal to the second device 604. Although shown as occurring separately from action 606, the CSI request can be sent immediately after the reference signal, for example, within the same time slot.

[0092] At action 610, the second device 604 measures a reference signal. This transmission and measurement of the reference signal is shown to occur after a request, although it is anticipated that the second device could be prepared to receive and measure the reference signal before receiving the request. The reference signal measurement may include one or more signal measurements, such as one or more signal measurements of the channel response used for channel estimation. These measurements form the basis for deriving a CSI report at the second device 604.

[0093] At action 612, the second device 604 forms a CSI report at L1 as part of SCI-2. Instead of passing the CSI report to the MAC layer or any other higher layer, the second device 604 groups the CSI report at the PHY layer to place it into one or more packets for transmission. In some aspects of this disclosure, the components of the CSI report are contained in a single new field of SCI-2; in other aspects, the individual components are contained in separate new fields of SCI-2. In some aspects of this disclosure, the CSI report includes only a subset of the RI indicator, CQI indicator, and PMI indicator.

[0094] At action 614, the second device 604 transmits an L1 message containing a CSI report in SCI-2 to the first device 60. By utilizing a higher coding rate, an SCI-2 containing a CSI report can occupy the same number of resource elements as an SCI-2 without a CSI report. Alternatively, to maintain the coding rate, an SCI-2 containing a CSI report can occupy a greater number of resource elements.

[0095] At action 616, the first device 602 retrieves the CSI report at the PHY layer. This is possible because the CSI message is sent by the second device 604 at L1. Therefore, the first device 602 is able to obtain CSI feedback from the second device 604 much faster than if the CSI feedback were contained in a higher-layer PDU (such as the MAC CE in the PSSCH payload).

[0096] Figure 7 This is a flowchart of a CSI report request method 700 according to some aspects of this disclosure. Aspects of method 700 may be performed by a computing device of a wireless communication device (e.g., a processor, processing circuitry, and / or other suitable components) or other suitable components for performing the steps. For example, between two UEs such as UEs 115a and 115b, UEs 115j and 115k, UEs 215b1 and 215b2, or 215a1 and 215a2, or two UEs 500. Aspects of method 700 may utilize one or more components such as a processor 502, a memory 504, a sidelink communication module 508, a transceiver 510, a modem 512, and the one or more antennas 516 to perform the steps of method 700. As shown, method 700 includes a plurality of enumerated steps, but aspects of method 700 may include additional steps before, after, and between the enumerated steps. In some aspects, one or more of the enumerated steps may be omitted or performed in a different order.

[0097] At box 702, a first UE (e.g., UE 500) may determine to request a Channel State Information (CSI) report from a second UE (e.g., another UE 500). This determination may be performed aperiodically or as part of the periodic function of the first UE.

[0098] At box 704, the first UE sets a value in a message to the second UE. This value can be a CSI request bit in SCI-2 (in the transmission to the second UE), or some other value indicating to the second UE that a CSI report is required.

[0099] At box 706, the first UE transmits a request for a CSI report, as set at box 704, and a reference signal to the second UE. The reference signal is transmitted to the second UE so that the second UE can perform measurements to determine information about the channel. The reference signal can be transmitted as part of the PSSCH, such as at the end of the PSSCH, for example, in resource slot 400 (…). Figure 4 The reference signal 408 is shown in the figure.

[0100] At box 708, the first UE responds to the request by receiving SCI-2 from the second UE, which includes a CSI report in the appropriate fields reserved for it. The first UE may receive the SCI-2 as an L1 signal. The CSI report may be contained in a single field of the SCI-2 or separated among multiple fields of each component. The components of the CSI report may include an RI indicator, a CQI indicator, and / or a PMI indicator.

[0101] At box 710, the first UE extracts the CSI report from SCI-2 at the PHY layer. Because the CSI report is processed at both the first and second UEs at the PHY layer (e.g., via a new field for CSI reporting in SCI-2 discussed herein), CSI feedback can be achieved faster than in other ways, thereby reducing latency and improving spectral efficiency. The first UE can then use the extracted information.

[0102] Figure 8 This is a flowchart of a CSI report transmission method 800 according to some aspects of this disclosure. Aspects of method 800 may be performed by a computing device of a wireless communication device (e.g., a processor, processing circuitry, and / or other suitable components) or other suitable components for performing the steps. For example, between two UEs such as UEs 115a and 115b, UEs 115j and 115k, UEs 215b1 and 215b2, or 215a1 and 215a2, or two UEs 500. Aspects of method 800 may utilize one or more components such as a processor 502, a memory 504, a sidelink communication module 508, a transceiver 510, a modem 512, and the one or more antennas 516 to perform the steps of method 800. As shown, method 800 includes a plurality of enumerated steps, but aspects of method 800 may include additional steps before, after, and between the enumerated steps. In some aspects, one or more of the enumerated steps may be omitted or performed in a different order.

[0103] At block 802, the first UE receives a request and reference signal for CSI feedback from the second UE. The request may be in the form of bits set in SCI-2 transmitted from the second UE. Other mechanisms for receiving the request are anticipated. Furthermore, the reference signal (e.g., CSI-RS or other suitable reference signal) may be received in the same time slot as the request.

[0104] At box 804, the first UE performs a channel measurement based on a reference signal. This measurement informs the subsequent generation of the CSI report.

[0105] At block 806, the first UE forms SCI-2 at the physical layer. SCI-2 includes a CSI report based on channel measurements from block 804. The CSI report may include several components. For example, the sidelink communication module may include a rank indicator (RI) in the CSI report. In some aspects of this disclosure, the rank indicator may include a single bit, although it may be of other lengths. The CSI report in SCI-2 may also include a measurement-based channel quality indicator. In some aspects of this disclosure, the channel quality indicator may be 4 bits long, although it may be of other lengths. Additionally, the CSI report in SCI-2 may include a measurement-based precoding matrix index (PMI) indicator in the CSI report. The length of the PMI may range from 1 to 6 bits (e.g., depending on one or more higher-layer parameters). Performing CSI report generation at the L1 (PHY layer) instead of at the MAC layer avoids the additional latency associated with moving data between layers and processing data at the MAC layer.

[0106] At block 808, the first UE transmits SCI-2 as a Layer 1 signal to the second UE in response to a request received at block 802. The CSI report is included in an SCI-2 field reserved for CSI according to embodiments of this disclosure. The various elements of the CSI report may be included in a single field. Alternatively, the RI, CQI, and PMI indicators may each be in their own fields within the SCI-2. Alternatively, two of these three fields may be in the same field, while the third is included in its own field. Finally, in addition to the RI, CQI, and PMI indicators, the CSI report may also include other information.

[0107] Therefore, using L1 signaling to transmit CSI reports helps reduce latency. For example, this low latency may be relevant in Ultra-Reliable Low Latency Communication (URLLC) use cases. By performing CSI reporting at L1, data does not need to be passed to other abstraction layers (such as the MAC layer). The lower latency can also improve link capacity and spectral efficiency.

[0108] Other aspects of this disclosure include the following:

[0109] 1. A method for wireless communication, comprising:

[0110] The first user equipment (UE) transmits a request for a channel state information (CSI) report to the second UE;

[0111] The first UE transmits a reference signal to the second UE;

[0112] In response to the request, the first UE receives second-stage side link control information (SCI-2) from the second UE, wherein the SCI-2 is a Layer 1 signal and includes one or more reporting fields for the CSI report; and

[0113] The first UE decodes the CSI report from the SCI-2 at the physical layer.

[0114] 2. The method according to aspect 1, wherein the one or more reporting fields include a rank indicator and a channel quality indicator for the CSI report.

[0115] 3. The method according to aspect 2, wherein the one or more reporting fields include a first field for the rank indicator and a second field for the channel quality indicator.

[0116] 4. The method according to any one of aspects 1-3, wherein the one or more reporting fields further include a precoded matrix index (PMI) indicator.

[0117] 5. The method according to aspect 4, wherein the one or more reporting fields include a first field for the rank indicator, a second field for the channel quality indicator, and a third field for the PMI indicator.

[0118] 6. The method according to any one of aspects 1-5, further comprising:

[0119] The first UE sets a bit to indicate the request for the CSI report.

[0120] The transmission of the request for the CSI report includes transmitting the bits to the second UE to trigger the CSI report.

[0121] The request includes SCI-2, which is a request from the first UE to the second UE.

[0122] 7. According to the method described in aspect 6, wherein:

[0123] The SCI-2 and the requested SCI-2 occupy the same number of resource elements, and

[0124] The requested SCI-2 includes a first coding rate, and the SCI-2 includes a second coding rate, the second coding rate being greater than the first coding rate.

[0125] 8. According to the method described in aspect 6, wherein:

[0126] The request SCI-2 occupies a first number of resource elements, and the SCI-2 occupies a second number of resource elements, the second number of resource elements being greater than the first number of resource elements.

[0127] 9. A method for wireless communication, comprising:

[0128] The first user equipment (UE) receives a request for a channel state information (CSI) report from the second UE;

[0129] The first UE receives the reference signal from the second UE;

[0130] The first UE performs channel measurement based on the reference signal; and

[0131] The first UE transmits second-stage side link control information (SCI-2) as a layer 1 signal to the second UE, the layer 1 signal including the CSI report based on the channel measurement.

[0132] 10. The method according to aspect 9, wherein the SCI-2 includes one or more reporting fields for the CSI report.

[0133] 11. The method according to aspect 10, wherein the one or more reporting fields include a rank indicator and a channel quality indicator for the CSI report.

[0134] 12. The method according to aspect 11, wherein the one or more reporting fields include a first field for the rank indicator and a second field for the channel quality indicator.

[0135] 13. The method according to any one of aspects 10-12, wherein the one or more reporting fields further include a precoded matrix index (PMI) indicator.

[0136] 14. The method according to aspect 13, wherein the one or more reporting fields include a first field for the rank indicator, a second field for the channel quality indicator, and a third field for the PMI indicator.

[0137] 15. The method according to any one of aspects 9-14, wherein the request includes bits declared in the request SCI-2 from the second UE.

[0138] 16. A first user equipment (UE), comprising:

[0139] The transceiver is configured as follows:

[0140] The request for a Channel State Information (CSI) report is transmitted to the second UE;

[0141] Transmit a reference signal to the second UE;

[0142] In response to the request, the second UE receives second-stage side link control information (SCI-2), wherein the SCI-2 is a Layer 1 signal and includes one or more reporting fields for the CSI report; and

[0143] The processor is configured to decode the CSI report from the SCI-2 at the physical layer.

[0144] 17. The first UE according to aspect 16, wherein the one or more reporting fields include a rank indicator and a channel quality indicator for the CSI report.

[0145] 18. The first UE according to aspect 17, wherein the one or more reporting fields include a first field for the rank indicator and a second field for the channel quality indicator.

[0146] 19. The first UE according to any one of aspects 16-18, wherein the one or more reporting fields further include a precoded matrix index (PMI) indicator.

[0147] 20. The first UE according to aspect 19, wherein the one or more reporting fields include a first field for the rank indicator, a second field for the channel quality indicator, and a third field for the PMI indicator.

[0148] 21. The first UE according to any one of aspects 16-20 further includes:

[0149] The processor is configured to set bits to indicate the request for the CSI report.

[0150] The transmission of the request for the CSI report includes transmitting the bits to the second UE to trigger the CSI report.

[0151] The request includes SCI-2, which is a request from the first UE to the second UE.

[0152] 22. The first UE according to aspect 21, wherein:

[0153] The SCI-2 and the requested SCI-2 occupy the same number of resource elements, and

[0154] The requested SCI-2 includes a first coding rate, and the SCI-2 includes a second coding rate, the second coding rate being greater than the first coding rate.

[0155] 23. The first UE according to aspect 21, wherein:

[0156] The request SCI-2 occupies a first number of resource elements, and the SCI-2 occupies a second number of resource elements, the second number of resource elements being greater than the first number of resource elements.

[0157] 24. A first user equipment (UE), comprising:

[0158] The transceiver is configured as follows:

[0159] Receive a request for a Channel State Information (CSI) report from the second UE;

[0160] Receive a reference signal from the second UE;

[0161] Perform channel measurements based on the reference signal; and

[0162] The second UE is transmitted second-stage side link control information (SCI-2), which is a layer 1 signal including the CSI report based on the channel measurement.

[0163] 25. The first UE according to aspect 24, wherein the SCI-2 includes one or more reporting fields for the CSI report.

[0164] 26. The first UE according to aspect 25, wherein the one or more reporting fields include a rank indicator and a channel quality indicator of the CSI report.

[0165] 27. The first UE according to aspect 26, wherein the one or more reporting fields include a first field for the rank indicator and a second field for the channel quality indicator.

[0166] 28. The first UE according to any one of aspects 25-27, wherein the one or more reporting fields further include a precoded matrix index (PMI) indicator.

[0167] 29. The first UE according to aspect 28, wherein the one or more reporting fields include a first field for the rank indicator, a second field for the channel quality indicator, and a third field for the PMI indicator.

[0168] 30. The first UE according to any one of aspects 24-29, wherein the request includes bits declared in the request SCI-2 from the second UE.

[0169] Information and signals can be represented using any of a variety of different techniques and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be mentioned throughout the above description can be represented by voltage, current, electromagnetic waves, magnetic fields or particles, light fields or particles, or any combination thereof.

[0170] The various illustrative blocks and modules described in connection with the disclosure herein may be implemented or performed using a general-purpose processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration).

[0171] The functions described herein can be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, these functions can be stored on or transmitted on a computer-readable medium as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of this disclosure and the appended claims. For example, due to the nature of software, the above-described functions can be implemented using software executed by a processor, hardware, firmware, hardwired, or any combination thereof. Features implementing the functions can also be physically located in various locations, including being distributed such that portions of the functions are implemented in different physical locations. Furthermore, as used herein, the word "or" in the list of items (e.g., a list of items beginning with phrases such as "at least one of" or "one or more of") indicates an inclusive list, such that a list such as [at least one of A, B, or C] refers to A or B or C or AB or AC or BC or ABC (i.e., A and B and C).

[0172] As will now be understood by those skilled in the art, and depending on the specific application at hand, many modifications, substitutions, and variations can be made to and of the materials, apparatus, configuration, and methods of use of the devices disclosed herein without departing from the spirit and scope of this disclosure. Therefore, the scope of this disclosure should not be limited to the specific embodiments illustrated and described herein, as they are merely examples, but should correspond fully to the scope of the appended claims and their functional equivalents.

Claims

1. A method for wireless communication, comprising: The first user equipment (UE) transmits a request for a Channel State Information (CSI) report to the second UE; The first UE transmits a reference signal to the second UE; In response to the request, the first UE receives second-stage side crosslink control information SCI-2 and first-stage side crosslink control information SCI-1 on the physical side crosslink control channel PSCCH from the second UE, wherein the SCI-2 is a layer 1 signal and includes the CSI report, the CSI report including one or more report fields; as well as The first UE decodes the CSI report from the SCI-2 at the physical layer based on the information indicated in the SCI-1. The one or more reporting fields mentioned therein include at least one of a rank indicator, a channel quality indicator, or a precoding matrix index (PMI) indicator.

2. The method of claim 1, wherein the one or more reporting fields include the rank indicator and the channel quality indicator for the CSI report.

3. The method of claim 2, wherein the one or more report fields include a first field for the rank indicator and a second field for the channel quality indicator.

4. The method of claim 2, wherein the one or more report fields further include the precoded matrix index PMI indicator.

5. The method of claim 4, wherein the one or more reporting fields include a first field for the rank indicator, a second field for the channel quality indicator, and a third field for the PMI indicator.

6. The method of claim 1, further comprising: The first UE sets a bit to indicate the request for the CSI report. The transmission of the request for the CSI report includes transmitting the bits to the second UE to trigger the CSI report. The request includes SCI-2, which is a request from the first UE to the second UE.

7. The method according to claim 6, wherein: The SCI-2 and the requested SCI-2 occupy the same number of resource elements, and The requested SCI-2 includes a first coding rate, and the SCI-2 includes a second coding rate, the second coding rate being greater than the first coding rate.

8. The method according to claim 6, wherein: The request SCI-2 occupies a first number of resource elements, and the SCI-2 occupies a second number of resource elements, the second number of resource elements being greater than the first number of resource elements.

9. A method for wireless communication, comprising: The first user equipment (UE) receives a request for a Channel State Information (CSI) report from the second UE. The first UE receives the reference signal from the second UE; The first UE performs channel measurements based on the reference signal; as well as The first UE transmits Phase 2 side crosslink control information (SCI-2) and Phase 1 side crosslink control information (SCI-1) on the physical side crosslink control channel (PSCCH) to the second UE. The SCI-2 is a Layer 1 signal, which includes the CSI report. The CSI report includes one or more report fields based on the channel measurements. The one or more report fields mentioned above include at least one of a rank indicator, a channel quality indicator, or a precoding matrix index (PMI) indicator. The SCI-1 includes information for decoding the SCI-2.

10. The method of claim 9, wherein the one or more reporting fields include the rank indicator and the channel quality indicator for the CSI report.

11. The method of claim 10, wherein the one or more reporting fields include a first field for the rank indicator and a second field for the channel quality indicator.

12. The method of claim 10, wherein the one or more report fields further include the precoded matrix index PMI indicator.

13. The method of claim 12, wherein the one or more reporting fields include a first field for the rank indicator, a second field for the channel quality indicator, and a third field for the PMI indicator.

14. The method of claim 9, wherein the request includes bits declared in the request SCI-2 from the second UE.

15. A first user equipment (UE), comprising: The transceiver is configured as follows: Transmit a request for a Channel State Information (CSI) report to the second UE; Transmit a reference signal to the second UE; as well as In response to the request, the second UE receives second-stage side crosslink control information SCI-2 and first-stage side crosslink control information SCI-1 on the physical side crosslink control channel PSCCH, wherein the SCI-2 is a layer 1 signal and includes the CSI report, the CSI report including one or more report fields; as well as The processor is configured as follows: The CSI report is decoded from SCI-2 at the physical layer based on the information indicated in SCI-1. The one or more reporting fields mentioned therein include at least one of a rank indicator, a channel quality indicator, or a precoding matrix index (PMI) indicator.

16. The first UE of claim 15, wherein the one or more reporting fields include the rank indicator and the channel quality indicator for the CSI report.

17. The first UE of claim 16, wherein the one or more reporting fields include a first field for the rank indicator and a second field for the channel quality indicator.

18. The first UE of claim 16, wherein the one or more reporting fields further include the precoded matrix index PMI indicator.

19. The first UE of claim 18, wherein the one or more reporting fields include a first field for the rank indicator, a second field for the channel quality indicator, and a third field for the PMI indicator.

20. The first UE according to claim 15, further comprising: The processor is configured to set bits to indicate the request in response to the CSI report. The transmission of the request for the CSI report includes transmitting the bits to the second UE to trigger the CSI report. The request includes SCI-2, which is a request from the first UE to the second UE.

21. The first UE according to claim 20, wherein: The SCI-2 and the requested SCI-2 occupy the same number of resource elements, and The requested SCI-2 includes a first coding rate, and the SCI-2 includes a second coding rate, the second coding rate being greater than the first coding rate.

22. The first UE according to claim 20, wherein: The request SCI-2 occupies a first number of resource elements, and the SCI-2 occupies a second number of resource elements, the second number of resource elements being greater than the first number of resource elements.

23. A first user equipment (UE), comprising: The transceiver is configured as follows: Receive a request for a Channel State Information (CSI) report from the second UE; Receive a reference signal from the second UE; Perform channel measurements based on the reference signal; and The second UE is transmitted with Phase 2 side crosslink control information SCI-2 and Phase 1 side crosslink control information SCI-1 on the physical side crosslink control channel PSCCH, wherein SCI-2 is a Layer 1 signal including the CSI report, and the CSI report includes one or more report fields based on the channel measurement. The one or more report fields mentioned above include at least one of a rank indicator, a channel quality indicator, or a precoding matrix index (PMI) indicator. The SCI-1 includes information for decoding the SCI-2.

24. The first UE of claim 23, wherein the one or more reporting fields include the rank indicator and the channel quality indicator for the CSI report.

25. The first UE of claim 24, wherein the one or more reporting fields include a first field for the rank indicator and a second field for the channel quality indicator.

26. The first UE of claim 24, wherein the one or more reporting fields further include the precoded matrix index PMI indicator.

27. The first UE of claim 26, wherein the one or more reporting fields include a first field for the rank indicator, a second field for the channel quality indicator, and a third field for the PMI indicator.

28. The first UE of claim 23, wherein the request includes bits declared in the request SCI-2 from the second UE.

29. An apparatus for wireless communication, the apparatus comprising components for performing the method according to any one of claims 1 to 8.

30. A computer-readable medium having program code recorded thereon, wherein, The program code can be executed by one or more processors to cause the processors to perform the method according to any one of claims 1 to 8.

31. A computer program product comprising computer-readable instructions that, when executed by one or more processors, cause the processors to perform the method according to any one of claims 1 to 8.

32. An apparatus for wireless communication, the apparatus comprising components for performing the method according to any one of claims 9 to 14.

33. A computer-readable medium having program code recorded thereon, wherein, The program code can be executed by one or more processors to cause the processors to perform the method according to any one of claims 9 to 14.

34. A computer program product comprising computer-readable instructions that, when executed by one or more processors, cause the processors to perform the method according to any one of claims 9 to 14.

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