Device and Method for CSI Acquisition on Side Link

Abstract

Apparatus and method for obtaining channel state information (CSI) on a sidelink are disclosed. The apparatus includes: a transmitter that transmits a reference signal to a device on a sidelink (SL) transmission; a receiver that receives a channel quality report from the device; and a processor that controls the transmitter and the receiver and decodes the channel quality report to obtain a channel quality; wherein the processor is configurable to support one or a combination selected from the group consisting of: a reporting activation scheme in which an SL channel state information (CSI) reporting activation indicator is configured; and a measurement trigger scheme in which the transmitter initiates transmission of the reference signal when a trigger condition is met.

Description

Technical Field

[0001] The subject matter disclosed herein generally relates to wireless communication, and more particularly, but not limited to, apparatuses and methods for obtaining channel state information (CSI) on a sidelink (SL). Background Art

[0002] The following acronyms and abbreviations are defined herein, at least some of which are referred to in the following description.

[0003] Third Generation Partnership Project (3GPP), 5th Generation (5G), New Radio (NR), 5G Node B (gNB), Long Term Evolution (LTE), LTE-Advanced (LTE-A), Evolved UTRAN Node B / Evolved Node B (eNB), Universal Mobile Telecommunications System (UMTS), Worldwide Interoperability for Microwave Access (WiMAX), Evolved UMTS Terrestrial Radio Access Network (E-UTRAN), Wireless Local Area Network (WLAN), Orthogonal Frequency Division Multiplexing (OFDM), Single Carrier Frequency Division Multiple Access (SC-FDMA), Downlink (DL), Uplink (UL), User Equipment / Device (UE), Network Equipment (NE), Radio Access Technology (RAT), Hybrid Automatic Repeat reQuest (HARQ), Acknowledgment (ACK), Hybrid Automatic Repeat reQuest - Acknowledgment (HARQ-ACK), Negative Acknowledgment (NACK), Receive / Receiver (RX), Transmit / Transmitter (TX), Physical SideLink Shared Channel (PSSCH), Physical Uplink Control Channel (PUCCH), Physical Uplink Shared Channel (PUSCH), Bandwidth Part (BWP), Control Element (CE), Channel State Information (CSI), Channel State Information Reference Signal (CSI-RS), Vehicle-to-Everything (V2X), Cellular V2X (C-V2X), Vehicle-to-Vehicle (V2V), Vehicle-to-Infrastructure (V2I), Vehicle-to-Network (V2N), Vehicle-to-Pedestrian (V2P), Vehicle-to-Device (V2D), Vehicle-to-Grid (V2G), Device-to-Device (D2D), Downlink Control Information (DCI), Demodulation Reference Signal (DMRS, DM-RS), Frequency Division Multiple Access (FDMA), Medium Access Control (MAC), Proximity Services (ProSe), Quality of Service (QoS), Radio Resource Control (RRC), Reference Signal (RS), Reference Signal Received Power (RSRP), Sounding Reference Signal (SRS), Channel Quality Indicator (CQI), Layer 1 Reference Signal Received Power (L1-RSRP), Precoder Matrix Indicator (PMI), Rank Indicator (RI), SideLink Control Information (SCI), Channel Busy Ratio (CBR), PC5 5G QoS Identifier (PQI). As used herein, "HARQ-ACK" may collectively refer to both Acknowledgment (ACK) and Negative Acknowledgment (NACK). ACK means that the TB was correctly received, while NACK means that the TB was incorrectly received.

[0004] In wireless communications such as a Third Generation Partnership Project (3GPP) mobile network, a wireless mobile network may provide seamless wireless communication services to a wireless communication terminal with mobility, i.e., a User Equipment (UE). The wireless mobile network may be formed by a plurality of base stations and the base stations may perform wireless communication with the UE.

[0005] 5G New Radio (NR) is the latest in the 3GPP standard series and supports very high data rates and lower latency compared to its predecessor LTE (4G) technology. Two types of frequency ranges (FR) are defined in 3GPP. Frequencies in the sub-6 GHz range (from 450 to 6000 MHz) are called FR1, and the millimeter wave range (from 24.25 GHz to 52.6 GHz) is called FR2. 5G NR supports both FR1 and FR2 frequency bands.

[0006] Vehicle-to-Everything (V2X) communication is the transfer of information from a vehicle to any entity that may affect the vehicle and vice versa. It is a vehicle communication system that incorporates other more specific communication types such as V2I (Vehicle-to-Infrastructure), V2N (Vehicle-to-Network), V2V (Vehicle-to-Vehicle), V2P (Vehicle-to-Pedestrian), V2D (Vehicle-to-Device), and V2G (Vehicle-to-Grid). V2X is a key technology for future intelligent transportation systems, and its application will enhance road safety and traffic efficiency, reduce congestion and energy consumption. Depending on the underlying technology used, there are two V2X communication technologies: WLAN-based and cellular-based.

[0007] V2X communication using a wireless mobile network is called Cellular V2X (or C-V2X) to distinguish it from WLAN-based V2X. 3GPP released V2X specifications based on LTE as the underlying technology in 2016 and has been continuously expanding V2X capabilities to support fifth-generation (5G) access networks, which can also be referred to as New Radio (NR) access networks. Summary of the Invention

[0008] Apparatus and methods for obtaining channel state information (CSI) on a sidelink are disclosed.

[0009] According to a first aspect, there is provided an apparatus comprising: a transmitter that transmits a reference signal to a device on a sidelink (SL) transmission; a receiver that receives a channel quality report from the device; and a processor that controls the transmitter and the receiver and decodes the channel quality report to obtain channel quality; wherein the processor is configurable to support one or a combination selected from the group consisting of: a reporting activation scheme, wherein an SL channel state information (CSI) reporting activation indicator is configured; and a measurement trigger scheme, wherein the transmitter initiates transmission of the reference signal when a trigger condition is met.

[0010] According to a second aspect, there is provided an apparatus, comprising: a receiver that receives a reference signal from a device on a sidelink (SL) transmission; a transmitter that transmits a channel quality report to the device; and a processor that controls the transmitter and the receiver and measures the channel quality based on the received reference signal; wherein the processor is configurable to support one or a combination selected from the group consisting of: a reporting activation scheme, in which an SL channel state information (CSI) reporting activation indicator is configured; and a measurement triggering scheme, in which the processor measures the channel quality when a triggering condition is met.

[0011] According to a third aspect, there is provided a method, comprising: transmitting, by a transmitter, a reference signal to a device on a sidelink (SL) transmission; receiving, by a receiver, a channel quality report from the device; and decoding, by a processor, the channel quality report to obtain the channel quality; wherein the processor controls the transmitter and the receiver and is configurable to support one or a combination selected from the group consisting of: a reporting activation scheme, in which an SL channel state information (CSI) reporting activation indicator is configured; and a measurement triggering scheme, in which the transmitter initiates transmission of the reference signal when a triggering condition is met.

[0012] According to a fourth aspect, there is provided a method, comprising: receiving, by a receiver, a reference signal from a device on a sidelink (SL) transmission; transmitting, by a transmitter, a channel quality report to the device; and measuring, by a processor, the channel quality based on the received reference signal; wherein the processor controls the transmitter and the receiver and is configurable to support one or a combination selected from the group consisting of: a reporting activation scheme, in which an SL channel state information (CSI) reporting activation indicator is configured; and a measurement triggering scheme, in which the processor measures the channel quality when a triggering condition is met. Description of the Drawings

[0013] A more specific description of the embodiments is provided below with reference to specific embodiments shown in the drawings. Given that these drawings only depict some embodiments and are therefore not considered to be a limitation of the scope, the embodiments are described and explained below with additional specificity and detail by using the drawings, in which:

[0014] Figure 1 is a schematic diagram illustrating a wireless communication system;

[0015] Figure 2 is a schematic block diagram illustrating components of a user equipment (UE) according to an embodiment;

[0016] Figure 3 is a schematic block diagram illustrating components of a network device (NE) according to an embodiment;

[0017] Figure 4FIG. is a schematic diagram illustrating a sidelink CSI acquisition process triggered by a TX UE according to an embodiment;

[0018] Figure 5 FIG. is a schematic diagram illustrating a sensing window and a resource selection window according to an embodiment;

[0019] Figure 6 FIG. is a schematic diagram illustrating a sidelink CSI acquisition process triggered by an RX UE according to an embodiment;

[0020] Figure 7 FIG. is a flowchart illustrating steps of a sidelink CSI acquisition process for a TX UE according to an embodiment; and

[0021] Figure 8 FIG. is a flowchart illustrating steps of a sidelink CSI acquisition process for an RX UE according to an embodiment. DETAILED DESCRIPTION

[0022] As will be understood by those skilled in the art, aspects of the embodiments can be embodied as a system, apparatus, method, or program product. Accordingly, the embodiments can take the form of an all-hardware embodiment, an all-software embodiment (including firmware, resident software, microcode, etc.), or an embodiment combining software and hardware solutions.

[0023] For example, the disclosed embodiments can be implemented as hardware circuits, including custom very large scale integration (VLSI) circuits or gate arrays, existing semiconductors such as logic chips, transistors, or other discrete components. Additionally, the disclosed embodiments can be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices, etc. As another example, the disclosed embodiments can include one or more physical or logical blocks of executable code, e.g., organized as objects, procedures, or functions.

[0024] Furthermore, one or more embodiments can take the form of a program product embodied in one or more computer-readable storage devices, which store machine-readable code, computer-readable code, and / or program code, hereinafter referred to as "code". The storage device can be tangible, non-transitory, and / or non-transmissive.

[0025] Any combination of one or more computer-readable media can be utilized. The computer-readable medium can be a computer-readable storage medium. The computer-readable storage medium can be a storage device storing the code. The storage device can be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, holographic, micro-mechanical, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.

[0026] A non-exhaustive list of more specific examples of storage devices can include the following: electrical connections with one or more cables, portable computer floppy disks, hard disks, random access memory ("RAM"), read-only memory ("ROM"), erasable programmable read-only memory ("EPROM" or flash memory), portable compact disc read-only memory ("CD-ROM"), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing. In the context of this document, a computer-readable storage medium can be any tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device.

[0027] References in this specification to "one embodiment", "an embodiment", "an example", "some embodiments", or similar language mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the phrases "in one embodiment", "in an embodiment", "in some embodiments", and similar language that appear throughout this specification may, but do not necessarily, all refer to the same embodiment, but rather mean "one or more embodiments". They may or may not include all of the disclosed embodiments. Unless otherwise expressly stated, the term "comprising" and its variants mean "comprising but not limited to".

[0028] Unless otherwise expressly stated, the listed items in a list do not imply that any or all of the items are mutually exclusive. Unless otherwise expressly stated, the terms "a", "an", and "the" also mean "one or more".

[0029] Throughout the disclosure, the terms "first", "second", "third", etc. are used as terms only for reference to related devices, components, program steps, etc., and do not denote any spatial or temporal order, unless otherwise expressly stated. For example, "a first device" and "a second device" can refer to two separately formed devices, or two parts or components of the same device. In some cases, for example, "a first device" and "a second device" can be the same and can be arbitrarily named. Similarly, the "first step" of a method or process can be performed after or simultaneously with the "second step".

[0030] Furthermore, the features, structures, or characteristics of the described embodiments can be combined in any suitable manner. In the following description, numerous specific details are provided, such as examples of programming, software modules, user selections, network transactions, database queries, database structures, hardware modules, hardware circuits, hardware chips, etc., to provide a thorough understanding of the embodiments. However, those skilled in the relevant art will recognize that the embodiments can be practiced without one or more of the specific details or by other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the embodiments.

[0031] Aspects of various embodiments are described below with reference to schematic flow charts and / or schematic block diagrams of methods, devices, systems, and program products. It will be understood that each step in the schematic flow charts and / or schematic block diagrams, as well as combinations of steps in the schematic flow charts and / or schematic block diagrams, can be implemented by code. The code can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device to produce a machine, such that instructions executed by the processor of the computer or other programmable data processing device can create a means for implementing the functions or actions specified in the schematic flow charts and / or schematic block diagrams.

[0032] The code may also be stored in a storage device that can direct a computer, other programmable data processing device, or other device to operate in a specific manner so that the instructions stored in the storage device can produce an article of manufacture including instructions for implementing the functions or actions specified in the schematic flowchart and / or schematic block diagram.

[0033] The code may also be loaded onto a computer, other programmable data processing device, or other device to cause a series of operational steps to be performed on the computer, other programmable device, or other device to produce a computer-implemented process, such that the code executed on the computer or other programmable device can provide a process for implementing the functions or actions specified in the schematic flowchart and / or schematic block diagram.

[0034] The schematic flow charts and / or schematic block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of different devices, systems, methods, and program products according to various embodiments. In this regard, each step in the schematic flow charts and / or schematic block diagrams may represent a portion of a module, fragment, or code, which includes one or more executable instructions of a code for implementing (one or more) specified logical functions. However, those skilled in the relevant art will recognize that the flow charts do not need to be practiced in the order shown and can be practiced without one or more specific steps or by other steps not shown.

[0035] It should also be noted that in some alternative embodiments, the functions mentioned in the identified blocks do not necessarily appear in the order mentioned in the figures. For example, depending on the functions involved, two steps shown in succession may actually be performed simultaneously, or may sometimes be performed in the reverse order. Other steps and methods are contemplated that are equivalent in function, logic, or effect to one or more steps or portions of steps shown in the figures.

[0036] The description of an element in each figure may refer to the elements of the previous figure. In all figures, the same reference numerals represent the same elements, including alternative embodiments of the same elements.

[0037] Figure 1 is a schematic diagram of an illustrated wireless communication system. It depicts an embodiment of a wireless communication system 100 with V2X side-link communication. In one embodiment, the wireless communication system 100 may include user equipment (UE) 102 and network equipment (NE) 104. Although a specific number of UEs 102 and NEs 104 are depicted in Figure 1 , those skilled in the art will recognize that any number of UEs 102 and NEs 104 may be included in the wireless communication system 100.

[0038] The UE 102 may be referred to as a remote device, remote unit, subscriber unit, mobile station, mobile station, user, terminal, mobile terminal, fixed terminal, subscriber station, user terminal, device, equipment, or other terms used in the art.

[0039] In one embodiment, the UE 102 may be an autonomous sensor device, alarm device, actuator device, remote control device, etc. In some other embodiments, the UE 102 may include a computing device, such as a desktop computer, laptop computer, personal digital assistant (PDA), tablet computer, smart phone, smart TV (e.g., a TV connected to the Internet), set-top box, gaming console, security system (including security cameras), in-vehicle computer, network equipment (e.g., router, switch, modem), etc. In some embodiments, the UE 102 includes a wearable device, such as a smart watch, fitness band, optical head-mounted display, etc. The UE 102 may communicate directly with one or more NEs 104.

[0040] The NE 104 may also be referred to as a base station, access point, access terminal, base station, Node-B, eNB, gNB, home Node-B, relay node, device, equipment, or any other term used in the art. Throughout the specification, references to a base station may refer to any of the above reference types of network equipment 104, such as eNBs and gNBs.

[0041] The NE 104 may be distributed over a geographical area. The NE 104 is typically part of a radio access network that includes one or more controllers communicatively coupled to one or more corresponding NEs 104. The radio access network is typically communicatively coupled to one or more core networks, which may be coupled to other networks, such as the Internet and the public switched telephone network. These and other elements of the radio access and core networks are not depicted but are well known to those of ordinary skill in the art.

[0042] In one embodiment, the wireless communication system 100 complies with 3GPP 5G New Radio (NR). In some embodiments, the wireless communication system 100 complies with the 3GPP protocol, where the NE 104 transmits on the downlink (DL) using an OFDM modulation scheme, and the UE 102 transmits on the UL using an SC-FDMA scheme or an OFDM scheme. However, more generally, the wireless communication system 100 may implement some other open or proprietary communication protocols, such as WiMAX. The present disclosure is not intended to be limited to embodiments of any particular wireless communication system architecture or protocol.

[0043] The NE 104 may serve multiple UEs 102, for example, within the serving area of a cell (or cell sector) or more cells via a wireless communication link. The NE 104 transmits DL communication signals to serve the UEs 102 in the time domain, frequency domain, and / or spatial domain.

[0044] Communication links are provided between the NE 104 and the UEs 102a, 102b, 102c, and 102d, which may be, for example, NR UL or DL communication links. Some UEs 102 may communicate with different radio access technologies (RATs) simultaneously, such as NR and LTE.

[0045] Direct or indirect communication links may be provided between two or more NEs 104.

[0046] In a V2X network, the UE may be a vehicle or in-vehicle device 102a, 102b, 102c, or a pedestrian-carried device 102d. A sidelink (SL) is a communication mechanism between a special UE or device-to-device (D2D) without going through the base station 104. In this case, communication with the base station is not required, and Proximity Services (ProSe) is a feature of the direct communication architecture between specified UEs. As part of the ProSe service, a new D2D interface (designated as PC5 and also called the sidelink at the physical layer) is introduced. The sidelink may refer to the direct communication between a vehicle and other devices (e.g., V2V, V2I), and it uses the PC5 interface. PC5 refers to the reference point where a user equipment (UE), i.e., a mobile terminal, communicates directly with another UE through a direct channel.

[0047] Figure 2FIG. is a schematic block diagram illustrating components of a user equipment (UE) according to one embodiment. The UE 200 may include a processor 202, a memory 204, an input device 206, a display 208, and a transceiver 210. In some embodiments, the input device 206 and the display 208 are combined into a single device, such as a touch screen. In certain embodiments, the UE 200 may not include any input device 206 and / or display 208. In various embodiments, the UE 200 may include one or more processors 202 and may not include an input device 206 and / or display 208.

[0048] In one embodiment, the processor 202 may include any known controller capable of executing computer-readable instructions and / or capable of performing logical operations. For example, the processor 202 may be a microcontroller, a microprocessor, a central processing unit (“CPU”), a graphics processing unit (“GPU”), an auxiliary processing unit, a field-programmable gate array (“FPGA”), or a similar programmable controller. In some embodiments, the processor 202 executes instructions stored in the memory 204 to perform the methods and routines described herein. The processor 202 is communicatively coupled to the memory 204 and the transceiver 210.

[0049] In one embodiment, the memory 204 is a computer-readable storage medium. In some embodiments, the memory 204 includes volatile computer storage media. For example, the memory 204 may include RAM, which includes dynamic RAM (“DRAM”), synchronous dynamic RAM (“SDRAM”), and / or static RAM (“SRAM”). In some embodiments, the memory 204 includes non-volatile computer storage media. For example, the memory 204 may include a hard disk drive, a flash memory, or any other suitable non-volatile computer storage device. In some embodiments, the memory 204 includes both volatile and non-volatile computer storage media. In some embodiments, the memory 204 stores data related to trigger conditions for transmitting measurement reports to a network device. In some embodiments, the memory 204 also stores program code and related data.

[0050] In one embodiment, the input device 206 may include any known computer input device, including a touch panel, buttons, a keyboard, a stylus, a microphone, etc. In some embodiments, the input device 206 may be integrated with the display 208, for example, as a touch screen or a similar touch-sensitive display. In some embodiments, the input device 206 includes a touch screen such that text can be input using a virtual keyboard displayed on the touch screen and / or by handwriting on the touch screen. In some embodiments, the input device 206 includes more than two different devices, such as a keyboard and a touch panel.

[0051] In one embodiment, the display 208 may include any known electronically controllable display or display device. The display 208 may be designed to output visual, audio, and / or tactile signals. In some embodiments, the display 208 includes an electronic display capable of outputting visual data to a user. For example, the display 208 may include, but is not limited to, an LCD display, an LED display, an OLED display, a projector, or a similar display device capable of outputting images, text, etc. to a user. As another non-limiting example, the display 208 may include a wearable display such as a smartwatch, smart glasses, a head-up display, etc. Additionally, the display 208 may be a component of a smartphone, a personal digital assistant, a television, a desktop computer, a notebook (laptop) computer, a personal computer, a vehicle dashboard, etc.

[0052] In certain embodiments, the display 208 includes one or more speakers for generating sound. For example, the display 208 may generate an audio alert or notification (e.g., a beep or a ring). In some embodiments, the display 208 includes one or more haptic devices for generating vibration, movement, or other tactile feedback. In some embodiments, all or a portion of the display 208 may be integrated with the input device 206. For example, the input device 206 and the display 208 may form a touchscreen or a similar touch-sensitive display. In other embodiments, the display 208 may be positioned close to the input device 206.

[0053] In one embodiment, the transceiver 210 is configured to communicate wirelessly with a network device. In certain embodiments, the transceiver 210 includes a transmitter 212 and a receiver 214. The transmitter 212 is used to transmit UL communication signals to the network device, and the receiver 214 is used to receive DL communication signals from the network device. For example, the transmitter 212 may transmit a HARQ-ACK including feedback for one or more DL transmissions. As another example, the receiver 214 may receive various configurations / data from the network device.

[0054] In some embodiments, the transmitter 212 may be used to transmit SL communication signals to another UE, while the receiver 214 may be used to receive SL communication signals from another UE.

[0055] The transmitter 212 and the receiver 214 may be any suitable type of transmitter and receiver. Although only one transmitter 212 and one receiver 214 are illustrated, the transceiver 210 may have any suitable number of transmitters 212 and receivers 214. For example, in some embodiments, the UE 200 includes multiple pairs of transmitters 212 and receivers 214 for communicating in multiple wireless networks and / or radio frequency bands, with each pair of transmitter 212 and receiver 214 configured to communicate in a different wireless network and / or radio frequency band.

[0056] Figure 3 FIG. is a schematic block diagram showing components of a network device (NE) 300 according to an embodiment.

[0057] NE 300 may include a processor 302, a memory 304, an input device 306, a display 308, and a transceiver 310. As can be understood, in some embodiments, the processor 302, the memory 304, the input device 306, the display 308, and the transceiver 310 may be similar to the processor 202, the memory 204, the input device 206, the display 208, and the transceiver 210 of the UE 200, respectively.

[0058] In some embodiments, the processor 302 controls the transceiver 310 to transmit DL signals / data to the UE 200. The processor 302 may also control the transceiver 310 to receive UL signals or data from the UE 200. For example, the processor 302 may control the transceiver 310 to receive PUCCH resources and / or PUCCH resources. In another example, the processor 302 may control the transceiver 310 to transmit a DL signal containing various configuration data to the UE 200, as described above.

[0059] In one embodiment, the transceiver 310 is configured to communicate wirelessly with the UE 200. In certain embodiments, the transceiver 310 includes a transmitter 312 and a receiver 314. The transmitter 312 is used to transmit DL communication signals to the UE 200, and the receiver 314 is used to receive UL communication signals from the UE 200.

[0060] The transceiver 310 may communicate with multiple UEs 200 simultaneously. For example, the transmitter 312 may transmit DL communication signals to the UE 200. As another example, the receiver 314 may receive UL communication signals from the UE 200 simultaneously. The transmitter 312 and the receiver 314 may be any suitable type of transmitter and receiver. Although only one transmitter 312 and one receiver 314 are shown, the transceiver 310 may have any suitable number of transmitters 312 and receivers 314. For example, the NE 300 may serve multiple cells and / or cell sectors, where the transceiver 310 includes a transmitter 312 and / or a receiver 314 for each cell or cell sector.

[0061] In the context of the Uu interface, NR supports channel characteristic measurement or estimation, i.e., channel sounding. The corresponding reference signals (RS) consist of the downlink channel state information reference signal (CSI-RS) and the uplink sounding reference signal (SRS). Regardless of the specific configuration, SRS can be regarded as the uplink equivalence to the downlink CSI-RS. For simplicity, the downlink CSI-RS is used as an example below to introduce issues related to channel sounding design.

[0062] The concept of CSI-RS was initially introduced in Long Term Evolution (LTE) Release 10 and reused in NR. The measurement of CSI-RS and the corresponding reporting to the network should be explicitly configured for the devices, i.e., multiple UEs. According to the 3GPP specifications, this configuration is done by means of a reporting configuration, which is called CSI-ReportConfig. Each reporting configuration mainly indicates the following items.

[0063] Report quantity:

[0064] For example, the report can include different combinations of the channel quality indicator (CQI), rank indicator (RI), and precoder matrix indicator (PMI). Alternatively, the configuration can indicate the reporting of the reference signal received power (RSRP). In addition to the higher layer RSRP reporting, NR also supports L1-RSRP reporting.

[0065] Measurement resources:

[0066] The reporting configuration also describes the downlink resource set on which the measurement should be performed in order to derive one or more quantities to be reported. The resource configuration is associated with at least one NZP-CSI-RSResourceSet used for measuring channel characteristics.

[0067] A single-port CSI-RS occupies a single resource element. A multi-port CSI-RS can be regarded as each antenna port CSI-RS of multi-orthogonal transmission, which shares the entire resource set assigned to the configured multi-port CSI-RS. Generally, an N-port CSI-RS occupies a total of N resource elements within one resource block in the frequency domain and one time slot in the time domain.

[0068] CSI-RS is configured for a given downlink bandwidth part (BWP) and uses the parameter set of the BWP. CSI-RS can be configured to cover the entire bandwidth of the BWP or only a part of the bandwidth. In the latter case, the CSI-RS bandwidth and the starting position in the frequency domain are provided as part of the CSI-RS configuration.

[0069] In the time domain, CSI-RS resource sets can be configured in a periodic, semi-persistent, or aperiodic manner. For a device, periodic CSI-RS transmissions occur every Nth time slot. In addition to the periodicity of N, the device is also configured with a specific time slot offset for CSI-RS transmissions. For semi-persistent CSI-RS transmissions, a certain CSI-RS periodicity and the corresponding time slot offset are configured. However, the actual CSI-RS transmissions can be activated or deactivated based on a Media Access Control (MAC) control element (CE). For aperiodic CSI-RS, no periodicity is configured. Instead, the device is explicitly triggered for each CSI-RS transmission instance by means of DCI signaling.

[0070] Report resources:

[0071] Similar to CSI-RS transmissions, reporting can be periodic, semi-persistent, or aperiodic.

[0072] Periodic reporting is done at a configured period and is always done on the Physical Uplink Control Channel (PUCCH). Thus, in the case of periodic reporting, the resource configuration also includes information about the PUCCH resources available for reporting at the configured periodicity.

[0073] In the case of semi-persistent reporting, the device is configured with periodic reporting instances in the same way as periodic reporting. However, the actual reporting can be activated or deactivated by means of a MAC CE. Semi-persistent reporting can be done on a periodically assigned PUCCH or Physical Uplink Shared Channel (PUSCH). The PUSCH is typically used for larger reporting payloads.

[0074] Aperiodic reporting is explicitly triggered by means of DCI - more specifically, within the CSI request field in the uplink scheduling grant (DCI format 0-1). Aperiodic reporting is always done on the scheduled PUSCH and thus requires an uplink scheduling grant.

[0075] In 5G V2X, the sidelink (SL) channel state information (CSI) should attempt to reuse the CSI framework for NR Uu. For SL communication, there may be several resource allocation mechanisms, including:

[0076] (1) Mode 1, where the base station schedules the UE for (one or more) sidelink resources to be used for (one or more) sidelink transmissions;

[0077] (2) Mode 2, where the UE determines (i.e., the base station does not schedule) (one or more) sidelink transmission resources;

[0078] (3) Mode 3, in which the resources for SL transmission between a pair of TX UE and RX UE are determined by another device, e.g., a third UE.

[0079] Given the characteristics specific to the sidelink, many issues are considered to ensure the efficiency of the CSI framework for NR sidelink. In view of the above different resource allocation mechanisms to handle these issues.

[0080] The first issue is how to determine and indicate the measurement resources.

[0081] In the case of mode 2 where the UE determines the (one or more) sidelink transmission resources, it is straightforward for the TX UE to determine the sidelink CSI-RS resource set. Since the UE may not need to perform CSI measurements in every SL slot, from the perspective of RS overhead efficiency, the sidelink CSI-RS can be configured in a non-periodic manner. In this case, it is necessary to indicate the presence of sidelink CSI-RS in the physical sidelink shared channel (PSSCH) resources. Such indication can be accomplished by means of an additional field of one bit within the sidelink control information (SCI).

[0082] In the case of mode 1, the above indication also applies to appropriate adaptation. In this case, the gNB can determine the measurement resources, which are in turn indicated from the gNB to the TX UE and then from the TX UE to the RX UE. Alternatively, the measurement resources determined by the gNB can be indicated to the TX UE and RX UE simultaneously.

[0083] The above indication can also be applied to the case of mode 3 with appropriate adaptation, e.g., by using a third UE to perform the function of the gNB in mode 1.

[0084] The second issue is how to trigger the SL CSI measurement and / or reporting of the RX UE.

[0085] In the case of mode 2, in the first option, in order to apply the knowledge of the channel quality when determining the transmission configuration, it is straightforward for the TX UE to trigger the SL CSI measurement and / or reporting of the RX UE. The above additional field in the SCI indicating the presence of CSI-RS in the PSSCH transmission can also be reused to trigger the SL CSI measurement and / or reporting of the RX UE. If the SCI is not available, the CSI measurement and reporting can be triggered by detecting CSI-RS within the preconfigured resources of the PSSCH transmission. Alternatively, as a second option, the RX UE can request the CSI measurement. For example, when identifying a lower successful decoding rate, the RX UE can request the TX UE to restart the SL CSI measurement and / or reporting cycle and thus re-determine the transmission configuration.

[0086] In the case of Mode 1, the above indication in the first option also applies to appropriate adaptation. SL CSI measurement and / or reporting can be triggered by the gNB, which allocates resources for SL via DL DCI signaling.

[0087] The above can also be applied to the case of Mode 3 with appropriate adaptation, for example, by using a third UE to perform the functions of the gNB in Mode 1.

[0088] The third issue is how to determine and indicate the reporting resources.

[0089] In the case of Mode 2, compared with the TX UE, the RX UE is more suitable for determining the reporting resources because the reporting transmission is performed by the RX UE. Additionally, the resources determined locally by the RX UE can reduce the latency caused by resource indication. The SCI can be used to indicate whether the report is conveyed in the PSSCH transmission.

[0090] In the case of Mode 1, the above indication also applies to appropriate adaptation. The gNB can determine the reporting resources. The reporting resources can be indicated from the gNB to the RX UE via the TX UE, or directly from the gNB to the RX UE. Additionally, the report can be transmitted to at least one of the TX UE and the gNB.

[0091] The above can also be applied to the case of Mode 3 with appropriate adaptation, for example, by using a third UE to perform the functions of the gNB in Mode 1.

[0092] In some embodiments, for the resource allocation mechanism of Mode 2, the SL CSI measurement and / or reporting is triggered by the TX UE.

[0093] Reference Figure 4 Describe a method for a side - link CSI acquisition process triggered by a TX UE according to an embodiment of the present invention, for example, including measurement and reporting. In the embodiment, the Mode 2 resource allocation mechanism is used, where the UE determines the side - link transmission resources.

[0094] In step 402, a sidelink (SL) CSI measurement configuration is transmitted and configured from TX UE 104a to RX UE 104b. This configuration indicates information such as the number of reports, measurement resources. Such a configuration can be determined by TX UE 104a and then sent to RX UE 104b. The transmission of the SL CSI measurement configuration can be done by means of sidelink radio resource control (RRC) or SCI. Alternatively, such a configuration can also be pre-configured. When the SL CSI measurement configuration is configured by the TX UE, the TX UE may not need to send the SL CSI measurement configuration for each instance of CSI measurement and / or reporting. In some embodiments, it can transmit the SL CSI measurement configuration only when the configuration changes.

[0095] The number of reports can include at least one of the following: channel quality indicator (CQI), rank indicator (RI), precoder matrix indicator (PMI), reference signal received power (RSRP), etc.

[0096] In step 404, the TX UE triggers the SL CSI measurement and / or reporting of the RX UE. The triggering can be done, for example, by means of an additional field of one bit in the SCI, which indicates the presence of sidelink CSI-RS in the PSSCH transmission.

[0097] When the triggering condition is met, the TX UE 104a can transmit a SL CSI measurement trigger to the RX UE 104b. The triggering condition can include at least one of the following: periodic timer, hybrid automatic repeat request (HARQ) feedback result, mobility state change, service QoS, service priority, etc.

[0098] In some cases, when the TX UE has no data to transmit, the CSI-RS can be transmitted as virtual data in the PSSCH. In this case, an additional field can be added in the SCI to indicate the presence of virtual data in the PSSCH that does not need to be decoded.

[0099] In step 406, the TX UE 104a transmits the SL CSI-RS to the RX UE 104b according to the SL CSI measurement configuration. The transmitter 212 of the TX UE 104a transmits a reference signal to the RX UE 104b on a sidelink (SL) transmission.

[0100] In some embodiments, the sidelink CSI measurement and / or reporting can be explicitly triggered. Compared with the CSI measurement trigger instance, the transmission of the SL CSI-RS can have an offset X410 in the time domain. The SL CSI-RS timing offset X410 refers to the time gap between the SL CSI measurement trigger transmission and the SL CSI-RS transmission. This offset can be defined in terms of the number of SL time slots or symbols and can be signaled in the SL CSI measurement configuration. Alternatively, the SL CSI-RS timing offset X can also be preconfigured.

[0101] In some embodiments, cross-slot scheduling may not be supported, i.e., the data transmission and the corresponding SCI indicating the resources for the data transmission must occur in the same SL time slot. In this case, the value of the offset X is set to zero; and the offset X can be preconfigured.

[0102] In some other embodiments, cross-slot scheduling is supported. The time gap between the SCI and the corresponding data transmission can be configurable. The value of the offset X410 can be set to a number not less than zero. In this case, the offset X410 can be signaled in the SL CSI measurement configuration.

[0103] If the sidelink CSI measurement and / or reporting is not explicitly triggered, the CSI measurement and / or reporting can be triggered by detecting the CSI-RS within the preconfigured resources of the PSSCH transmission.

[0104] In step 408, the RX UE reports the CSI measurement result (i.e., sends the SL CSI report and / or indicator) to the TX UE via the PSSCH transmission. To indicate the existence of such a report, SCI signaling can be used. The receiver 214 of the TX UE receives the channel quality report from the RX UE. The channel quality report can be decoded by the processor 202 of the TX UE to obtain the channel quality, i.e., the SL CSI is obtained.

[0105] In some cases, when the RX UE has no data to transmit, the CSI report can be sent as virtual data in the PSSCH. In this case, an additional field can be added to the SCI sent to the TX UE to indicate the existence of virtual data in the PSSCH that does not need to be decoded.

[0106] The SL CSI report timing offset Y412 can be specified. The offset Y412 refers to the maximum time gap between the SL CSI measurement trigger and the valid CSI report instance. In other words, it can be assumed to be valid only if the SL CSI report is transmitted within the offset Y412. The offset Y412 can be defined in terms of the number of SL time slots or symbols and can be configured in the SLCSI measurement configuration or preconfigured.

[0107] Offset Y 412 may be associated with at least one of the following factors: frequency band, bandwidth part (BWP), resource pool, channel busy ratio (CBR), UE capability, resource selection window, quality of service (QoS), priority level, and spectral efficiency.

[0108] A set of values of offset Y 412 is configured and stored in a database. For example, a list of offset Y 412 values may be stored in a lookup table, and the index key of the table may be used to retrieve it. Specific values may be selected for SL CSI measurement configuration.

[0109] In some embodiments, CSI configuration and CSI procedures including resource selection may be included in the 3GPP NR side-link specification.

[0110] For CSI configuration, an additional field may be added within the CSI configuration to indicate the configurable timing offset Y 412, which is the maximum time gap between the SL CSI measurement trigger and the valid CSI reporting instance.

[0111] For a CSI procedure including resource selection, on the TX UE side, when the SL CSI measurement trigger is transmitted, the TX UE starts a timer corresponding to offset Y. If the TX UE receives the corresponding CSI report from the RX UE before the timer expires, the TX UE stops the timer; otherwise, the TX UE restarts the SL CSI measurement cycle by transmitting a new SL CSI measurement trigger.

[0112] For a CSI procedure including resource selection, on the RX UE side, after receiving the SL CSI measurement trigger, the RX UE starts a timer corresponding to offset Y. When the RX UE selects resources based on sensing, it configures the resource selection window size based on existing policies and offset Y 412. Generally, the configured resource selection window size should not exceed offset Y 412. Therefore, if the RX UE can find available resources before the timer expires or within the configured resource selection window, the RX UE reports CSI accordingly; otherwise, the RX UE discards the CSI report.

[0113] Figure 5FIG. 0 is a schematic diagram showing a sensing window and a resource selection window according to an embodiment. In the example, the relationship between the offset Y 412 and the resource selection window 504 is as follows. The resource selection window 504 is defined as a time gap in which the UE selects the (one or more) sidelink resources for transmission. The RX UE senses the CSI-RS in the sensing window 502 and selects resources for transmission in the resource selection window 504 based on the sensing result. The value of the offset Y 412 can be used by the RX UE to determine the resource selection window boundary. For example, the resource selection window 504 may start from time slot N+T1 and end at time slot N+T2; and thus has a resource selection window size of ΔT (i.e., T2 - T1). The end boundary (N+T2) of the resource selection window should not be later than the end boundary (M+Y) of the valid reporting instance, where N represents the starting point for resource selection, and M represents the instance when the CSI measurement is triggered.

[0114] The concept of the SL CSI reporting timing offset Y 412 can be considered as an activation or deactivation mechanism for CSI reporting.

[0115] In some embodiments, the offset Y may also be referred to as the reporting activation indicator 412. Thus, the SL CSI measurement and / or reporting method can be referred to as a reporting activation scheme. The activation condition may refer to the condition that the time of the selected resource is within the offset Y, i.e., before the end of the valid reporting instance (M+Y), where M represents the instance when the CSI measurement is triggered; and the deactivation condition may refer to the condition that the time of the selected resource exceeds the offset Y, i.e., later than the valid reporting instance (M+Y), where M represents the instance when the CSI measurement is triggered. If the activation condition is met, it is expected to receive a channel quality report for the corresponding CSI-RS, and if the deactivation condition is met, it is expected not to receive a channel quality report for the corresponding CSI-RS.

[0116] Alternatively, the activation or deactivation indicator may be defined as, for example, a priority level. When configured, this priority level can be interpreted as the corresponding activation or deactivation indicator for both the TX UE and the RX UE.

[0117] When the SL CSI reporting conflicts with data transmission to a third UE, i.e., other than the destination UE (TX UE) of the SL CSI reporting, the conflict needs to be handled. The RX UE needs to determine which one should be executed, i.e., the SL CSI reporting or the data transmission. Therefore, there should be some criteria to indicate the priority levels of the SL CSI reporting and the data transmission. This can be done by configuring the SL CSI reporting with a priority level, as defined in the PQI (PC5 5G QoS identifier) for data transmission over the sidelink.

[0118] The priority for SL CSI reporting can be determined as follows. If the TX UE explicitly configures a PQI indicating the priority level for the SL CSI-RS and SL CSI report pair, this priority level can be used as the priority level for SL CSI reporting; otherwise, if the SL CSI-RS is transmitted together with data, the priority of the data can be used as the priority level for the CSI report corresponding to the CSI-RS. Otherwise, if the CSI report is transmitted together with data destined for the target UE of the SL CSI report, i.e., the TX UE, the priority level for the data can be used as the priority level for the SL CSI report. More specifically, the data can be any data in the data set that meets the transmission conditions for the SL CSI report, or the data can be the data with the highest priority level within the data set that meets the transmission conditions for the SL CSI report. In some embodiments, the highest priority level corresponds to the priority level with the lowest value. In some other embodiments, a pre-configured default priority level for the CSI-RS is used.

[0119] In some embodiments, the SL CSI report is given more opportunities to find available resources. For example:

[0120] If M + Y >= N + T2, i.e., the end boundary (N + T2) of the resource selection window is not later than the end boundary (M + Y) of the valid reporting instance, the sensing-based resource selection strategy for SL CSI reporting can be the same as the sensing-based resource selection strategy for data transmission.

[0121] If M + Y < N + T2, i.e., the end boundary (N + T2) of the resource selection window is later than the end boundary (M + Y) of the valid reporting instance, the length of the resource selection window for SL CSI reporting will be shorter than expected. To ensure that the SL CSI report can find available frequency resources within the shorter resource selection window, the constraints on resource selection for SL CSI reporting need to be relaxed compared to data transmission over the sidelink.

[0122] In sensing-based resource selection, this can be accomplished by increasing the sensing energy threshold for SL CSI reporting compared to data transmission. More specifically, if the sensing energy threshold is defined as a fixed value, the fixed value for the CSI report should be higher than that for data transmission.

[0123] If the sensing energy threshold is a range, the maximum threshold for the CSI report (i.e., the upper limit of the energy threshold) should be higher than the threshold for data transmission. In that case, more frequency utilization opportunities can be found for the SL CSI report.

[0124] In some embodiments, when there are multiple pairs of CSI-RS and CSI reports within a given duration, the association between the SL CSI report and the corresponding CSI-RS is identified.

[0125] The association can be accomplished by means of an additional field within the SCI that serves as an identifier for each pair of CSI-RS and CSI report. Specifically, the TX UE can assign an identifier to the new CSI-RS and configure such an identifier field in the SCI, which indicates the presence of the CSI-RS in the associated PSSCH transmission. The RX UE receives and identifies such an identifier and configures the identifier within the SCI indicating the presence of the CSI report to indicate which CSI-RS the CSI report belongs to.

[0126] Such an identifier can be used to identify the initial transmission and retransmission for each CSI-RS and the associated CSI report. Such an identifier can also be used to identify the transmissions for different pairs of CSI-RS and the associated CSI reports.

[0127] The maximum number of CSI-RS and CSI report pairs can be specified. This maximum number can be used to determine the length of the identifier in terms of bits.

[0128] In some other embodiments, for resource allocation mechanism mode 2, the SL CSI measurement and / or report can be requested by the RX UE.

[0129] Reference Figure 6 Describes a method for a side-link CSI acquisition process triggered by the RX UE for mode 2 according to another embodiment of the present disclosure, for example, including measurement and / or reporting. In this embodiment, the RX UE 104b requests the SL CSI measurement and / or report. That is, the SL CSI measurement and / or report is triggered by a measurement request from the RX UE 104b.

[0130] In step 601, the RX UE 104b sends an SL CSI measurement request to the TX UE 104a to start the SL CSI measurement and / or reporting procedure. The request can be accomplished by means of the SCI.

[0131] For example, when identifying a lower successful decoding rate, the RX UE 104b can request the TX UE 104a to restart the SL CSI measurement and / or reporting cycle and re-determine the transmission configuration.

[0132] In some embodiments, a measurement request may be considered as a trigger for SL CSI measurement and / or reporting. By transmitting a measurement request via the RX UE, or receiving a measurement request via the TX UE, the trigger condition can be met. Thus, this arrangement may also be referred to as a measurement trigger scheme, where the transmitter initiates the transmission of a reference signal when the trigger condition is met. Other trigger conditions may include a periodic timer, a hybrid automatic repeat request (HARQ) feedback result, a mobility state change, a service QoS, a service priority, etc.

[0133] In step 602, the transmission of the SL CSI measurement configuration can be accomplished by means of sidelink RRC or SCI. Alternatively, such a configuration can also be pre-configured. When the SL CSI measurement configuration is configured by the TX UE, the TX UE does not need to transmit the SL CSI measurement configuration for each instance of CSI measurement and / or reporting. It only needs to transmit the SL CSI measurement configuration when the configuration changes. Except that step 602 is executed when receiving an SL CSI measurement request from the RX UE, step 602 can be similar to step 402 of the previous method.

[0134] In step 604, the TX UE 104a triggers the SL CSI measurement and / or reporting of the RX UE. Step 604 can be similar to step 404 of the previous method.

[0135] In step 606, the TX UE transmits SL CSI-RS to the RX UE 104b according to the SL CSI measurement configuration. Step 606 can be similar to step 406 of the previous method.

[0136] In step 608, the RX UE reports the CSI measurement result to the TX UE via PSSCH transmission. Step 608 can be similar to step 408 of the previous method.

[0137] It can be provided in a manner similar to that of the Figure 4 SL CSI-RS timing offset X 410 of the previous method for the sidelink CSI-RS timing offset X 610.

[0138] Additionally or alternatively, the SL CSI reporting timing offset Y can also be defined and applied in this embodiment in a manner similar to that of the Figure 4 offset Y (report activation indicator) 412 of the previous method.

[0139] In some embodiments, sidelink CSI measurement and / or reporting is provided for resource allocation mechanism mode 1, similar to Figures 4 to 6The above-described embodiments as shown. Appropriate modifications and / or adaptations can be made. For example, the gNB can determine the reporting resources. The reporting resources can be indicated by the gNB to the RX UE via the TX UE, or directly indicated from the gNB to the RX UE. In addition, the report can be transmitted to at least one of the TX UE and the gNB.

[0140] In some embodiments, side-link CSI measurement and / or reporting is provided for resource allocation mechanism mode 3, similar to the embodiments of mode 1 described above. Appropriate modifications and / or adaptations can be made. For example, the functions of the gNB in mode 1 can be performed by using an additional device or a third UE.

[0141] In some embodiments, support for activating and / or deactivating CSI reporting for the SL is proposed. In the case of SL CSI acquisition, the reporting resources will be selected by the UE based on sensing. In some cases, if the reporting UE cannot find available reporting resources in a timely manner, such CSI measurement results will lose their efficiency in representing the channel attributes of the rapidly changing side-link. In such cases, such reporting should be avoided from the perspective of spectral efficiency. In contrast, for the Uu interface, there is no design for activating and / or deactivating CSI reporting. The CSI reporting resources are deterministically allocated and indicated by the eNB / gNB to the UE. Therefore, there is no need to activate or deactivate CSI reporting for Uu CSI acquisition.

[0142] In some embodiments, a new trigger for updating the SL CSI measurement and / or reporting period is also proposed, supporting CSI measurement triggered by the RX UE.

[0143] Since the RX UE has knowledge of the real-time transmission state of the SL, supporting CSI measurement triggered by the RX UE can facilitate the rapid adaptation to SL channel changes. For example, when identifying a low successful decoding rate, the RX UE can request the TX UE to restart the SL CSI measurement and / or reporting period and re-determine the transmission configuration.

[0144] Figure 7 is a flowchart illustrating the steps of a side-link CSI acquisition process for the TX UE.

[0145] In step 702, the transmitter 212 on the TX UE side transmits a reference signal to a device on a side-link (SL) transmission. The device here can refer to the RX UE that communicates with the TX UE on the SL transmission.

[0146] In step 704, the receiver 214 on the TX UE side receives a channel quality report from the device.

[0147] In step 706, the processor 202 on the TX UE side decodes the channel quality report to obtain the channel quality.

[0148] The processor 202 controls the transmitter 212 and the receiver 214, and is configurable to support one or a combination selected from the group consisting of: a reporting activation scheme, in which an SL channel state information (CSI) reporting activation indicator is configured; and a measurement trigger scheme, in which the transmitter initiates the transmission of a reference signal when a trigger condition is met.

[0149] Figure 8 is a flowchart illustrating the steps of a sidelink CSI acquisition process for an RX UE.

[0150] In step 802, the receiver 214 on the RX UE side receives a reference signal from a device on a sidelink (SL) transmission. The device here may refer to a TX UE communicating with the RX UE on the SL transmission.

[0151] In step 804, the processor 202 on the RX UE side measures the channel quality based on the received reference signal.

[0152] In step 806, the transmitter 212 on the RX UE side transmits a channel quality report to the device.

[0153] The processor 202 controls the transmitter 212 and the receiver 214, and is configurable to support one or a combination selected from the group consisting of: a reporting activation scheme, in which an SL channel state information (CSI) reporting activation indicator is configured; and a measurement trigger scheme, in which the processor measures the channel quality when a trigger condition is met.

[0154] Various embodiments and / or examples are disclosed to provide exemplary and explanatory information, enabling those of ordinary skill in the art to put the disclosure into practice. Unless otherwise specifically indicated, features or components disclosed with reference to one embodiment or example are also applicable to all embodiments or examples.

[0155] The embodiments may be practiced in other specific forms. The described embodiments should be considered illustrative rather than restrictive in all respects. Thus, the scope of the present invention is indicated by the appended claims rather than by the foregoing description. All changes within the meaning and range of equivalents of the claims are covered within their scope.

Claims

1. A user equipment (UE) comprising: At least one memory; And At least one processor, the at least one processor being coupled to the at least one memory and configured to cause the UE to: Transmit a reference signal to a device on a sidelink (SL) transmission; Receive a channel quality report from the device; And Decode the channel quality report to obtain a channel quality; Wherein the at least one processor is configured to cause the UE to be configurable to support: A reporting activation scheme, wherein an SL channel state information (CSI) reporting activation indicator is configured; and A measurement trigger scheme, the measurement trigger scheme initiating transmission of the reference signal when a trigger condition is met, wherein the trigger condition includes a flag in sidelink control information (SCI).

2. The UE according to claim 1, wherein, In the case of supporting the reporting activation scheme, the UE expects the channel quality report when an activation condition is met, and the UE does not expect the channel quality report when a deactivation condition is met.

3. The UE according to claim 2, wherein, The SL CSI reporting activation indicator is preconfigured, or the at least one processor is configured to cause the UE to transmit a channel quality measurement configuration, and the SL CSI reporting activation indicator is configurable via the channel quality measurement configuration.

4. The UE according to claim 2, wherein, The SL CSI reporting activation indicator is the maximum time gap between a channel quality measurement trigger and a CSI reporting instance.

5. The UE according to claim 4, wherein, The SL CSI reporting activation indicator is defined in terms of the number of SL time slots or symbols.

6. The UE according to claim 4, wherein, The at least one processor is configured to cause the UE to transmit an SL CSI measurement trigger, and when transmitting the SL CSI measurement trigger, the processor starts a timer corresponding to the maximum time gap.

7. The UE according to claim 2, wherein, The channel quality report includes a report quantity, the report quantity including one or a combination selected from the group consisting of: a channel quality indicator (CQI), a rank indicator (RI), a precoder matrix indicator (PMI), and a reference signal received power (RSRP).

8. The UE according to claim 1, wherein The time-frequency resource for transmitting the reference signal is allocated by one selected from the group consisting of: a base station, the UE, and another device.

9. The UE according to claim 1, wherein, In the case where the UE has no data to transmit, the reference signal is transmitted as virtual data in a physical sidelink shared channel (PSSCH).

10. A user equipment (UE) comprising: At least one memory; And At least one processor, the at least one processor being coupled to the at least one memory and configured to cause the UE to: Receive a reference signal from a device on a sidelink (SL) transmission; Transmit a channel quality report to the device; And Measure a channel quality based on the received reference signal; Wherein the at least one processor is configured to cause the UE to be configurable to support: A reporting activation scheme, wherein an SL channel state information (CSI) reporting activation indicator is configured; and A measurement trigger scheme, the measurement trigger scheme measuring the channel quality when a trigger condition is met, wherein the trigger condition includes a flag in sidelink control information (SCI).

11. The UE according to claim 10, wherein When the reporting activation scheme is supported, the at least one processor is configured to cause the UE to transmit the channel quality report when the activation condition is met, and not to transmit the channel quality report when the deactivation condition is met.

12. The UE according to claim 11, wherein, The SL CSI report activation indicator is pre-configured, or in the case where the UE further receives channel quality measurement configuration, the SL CSI report activation indicator can be configured via the channel quality measurement configuration; The SL CSI report activation indicator is the maximum time gap between a channel quality measurement trigger and a CSI report instance; Or a combination thereof.

13. The UE according to claim 10, wherein, The SL CSI report activation indicator is defined in terms of the number of SL time slots or symbols.

14. The UE according to claim 12, wherein, The at least one processor is further configured to cause the UE to receive an SL CSI measurement trigger, and when the SL CSI measurement trigger is received, the processor starts a timer corresponding to the maximum time gap.

15. The UE according to claim 11, wherein, The channel quality report includes a reported quantity, and the reported quantity includes one or a combination selected from the group consisting of: a channel quality indicator (CQI), a rank indicator (RI), a precoder matrix indicator (PMI), and a reference signal received power (RSRP).

16. The UE according to claim 10, wherein, The time-frequency resource for transmitting the channel quality report is allocated by one selected from the group consisting of: a base station, the UE, and other devices.

17. The UE according to claim 10, wherein, When the measurement trigger scheme is supported, the trigger condition is met when a reference signal is detected within a physical sidelink shared channel (PSSCH) transmission, or when a flag in the SCI is detected.

18. A method performed by a user equipment (UE), comprising: Transmitting a reference signal to a device on a sidelink (SL) transmission; Receiving a channel quality report from the device; Decoding the channel quality report to obtain channel quality; And Supporting: A reporting activation scheme, in which an SL channel state information (CSI) report activation indicator is configured; And A measurement trigger scheme, which initiates the transmission of the reference signal when a trigger condition is met, wherein the trigger condition includes a flag in sidelink control information (SCI).

19. The method according to claim 18, wherein, When the reporting activation scheme is supported, the UE expects the channel quality report when the activation condition is met, and the UE does not expect the channel quality report when the deactivation condition is met.

20. The method according to claim 18, wherein The SL CSI report activation indicator is the maximum time gap between a channel quality measurement trigger and a CSI report instance.

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