Device and method for selecting resources in a wireless communication system

Abstract

The present disclosure relates to a quasi-fifth generation (5G) or 5G communication system that is provided to support higher data rates than fourth generation (4G) communication systems such as long term evolution (LTE). The present disclosure relates to selecting resources in a wireless communication system. A method for operating a user equipment (UE) is provided. The method includes: obtaining configuration information of multiple sidelink resource pools; and using one of the multiple sidelink resource pools to transmit a sidelink signal to another UE. The multiple sidelink resource pools can be configured within equal bandwidth parts (BWPs).

Description

Technical Field

[0001] The present disclosure relates to a wireless communication system, and more particularly, to an apparatus and method for selecting resources in a wireless communication system. Background Art

[0002] To meet the increasing demand for wireless data traffic since the deployment of the 4th generation (4G) communication system, efforts have been made to develop improved 5th generation (5G) or pre-5G communication systems. Therefore, 5G or pre-5G communication systems are also referred to as "beyond 4G networks" or "post-Long Term Evolution (LTE) systems."

[0003] 5G communication systems are expected to be implemented in higher-frequency (millimeter wave) bands (e.g., the 60 GHz band) to achieve higher data rates. To reduce radio wave propagation losses and increase transmission distances, beamforming, massive multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and large antenna technologies are being discussed in 5G communication systems.

[0004] In addition, in 5G communication systems, development of system network improvements is underway based on advanced small cells, cloud radio access networks (RAN), ultra-dense networks, device-to-device (D2D) communications, wireless backhaul, mobile networks, cooperative communications, coordinated multi-point (CoMP), receiver-side interference cancellation, and more.

[0005] In 5G systems, hybrid frequency shift keying (FSK) and quadrature amplitude modulation (FQAM) and sliding window superposition coding (SWSC) have been developed as advanced coded modulation (ACM), as well as filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) as advanced access technologies.

[0006] The 5G communication system supports vehicle communication. In the case of vehicle communication, 3GPP Rel-14 and Rel-15 based on device-to-device (D2D) communication have completed the standardization of vehicle-to-everything (V2X) based on LTE, and research on the development of V2X based on 5G New Radio (NR) is currently underway. In NR V2X, unicast communication, groupcast communication, multicast communication, and broadcast communication are supported between user equipments (UEs). In addition, unlike LTE V2X, NR V2X aims to provide further evolved services such as smart convoys, advanced driving, expanded sensors, and remote driving, thereby aiming to send and receive basic safety information required for vehicle driving.

[0007] The above information is presented as background information only to assist in understanding the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above may be applied as prior art with respect to the present disclosure. Summary of the Invention

[0008] Solution to the problem

[0009] Aspects of the present disclosure are to address at least the above-mentioned problems and / or disadvantages and to provide at least the advantages described below. Therefore, one aspect of the present disclosure is to provide a method for efficiently providing a sidelink service in a wireless communication system.

[0010] Another aspect of the present disclosure is to provide an apparatus and method for configuring multiple sidelink resource pools in a wireless communication system.

[0011] Another aspect of the present disclosure is to provide an apparatus and method for selecting one of a plurality of resource pools when a plurality of side link resource pools are configured in a wireless communication system.

[0012] Another aspect of the present disclosure is to provide an apparatus and method for transmitting sidelink control information and data information through resources selected within a sidelink resource pool selected by a sidelink transmitting user equipment (UE) in a wireless communication system.

[0013] Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the presented embodiments.

[0014] According to one aspect of the present disclosure, a method for operating a UE in a wireless communication system is provided. The method includes: obtaining configuration information of multiple sidelink resource pools; and using one of the multiple sidelink resource pools to transmit a sidelink signal to another UE. The multiple sidelink resource pools can be configured within equal bandwidth parts (BWPs).

[0015] According to another aspect of the present disclosure, a UE in a wireless communication system is provided. The UE includes a transceiver and at least one processor operatively coupled to the transceiver. The at least one processor can be configured to: obtain configuration information of multiple sidelink resource pools; and use one of the multiple sidelink resource pools to transmit a sidelink signal to another UE. The multiple sidelink resource pools can be configured within an equal BWP.

[0016] Apparatuses and methods according to various embodiments may improve reception reliability of sidelink control information, data, and feedback information, as well as resource usage efficiency in vehicle communication or device-to-device (D2D) communication.

[0017] Other aspects, advantages, and salient features of the present disclosure will become apparent to those skilled in the art from the following detailed description of various embodiments of the present disclosure, which is presented in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and other aspects, features and advantages of certain embodiments of the present disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0019] Figure 1 A wireless communication system according to an embodiment of the present disclosure is shown;

[0020] Figure 2 shows a configuration of a base station (BS) in a wireless communication system according to an embodiment of the present disclosure;

[0021] Figure 3 The present invention shows a configuration of a UE in a wireless communication system according to an embodiment of the present disclosure;

[0022] Figure 4 shows a configuration of a communication unit in a wireless communication system according to an embodiment of the present disclosure;

[0023] Figure 5A An example of a scenario of sidelink communication in a wireless communication system according to an embodiment of the present disclosure is shown;

[0024] Figure 5B An example of a scenario of sidelink communication in a wireless communication system according to an embodiment of the present disclosure is shown;

[0025] Figure 5C An example of a scenario of sidelink communication in a wireless communication system according to an embodiment of the present disclosure is shown;

[0026] Figure 5D An example of a scenario of sidelink communication in a wireless communication system according to an embodiment of the present disclosure is shown;

[0027] Figure 6A An example of a sidelink communication transmission scheme in a wireless communication system according to an embodiment of the present disclosure is shown;

[0028] Figure 6B An example of a sidelink communication transmission scheme in a wireless communication system according to an embodiment of the present disclosure is shown;

[0029] Figure 7 An example of a link related to sidelink communication in a wireless communication system according to an embodiment of the present disclosure is shown;

[0030] Figure 8 An example of a protocol stack of a sidelink UE in a wireless communication system according to an embodiment of the present disclosure is shown;

[0031] Figure 9 An example of a sidelink resource pool in a wireless communication system according to an embodiment of the present disclosure is shown;

[0032] Figure 10 An example of a sidelink frame structure in a wireless communication system according to an embodiment of the present disclosure is shown;

[0033] Figure 11 An example of allocation of timeline resources of a sidelink resource pool in a wireless communication system according to an embodiment of the present disclosure is shown;

[0034] Figure 12 The invention shows a sidelink unicast communication process in a wireless communication system according to an embodiment of the present disclosure;

[0035] Figure 13 Another example of a unicast communication process in a wireless communication system according to an embodiment of the present disclosure is shown;

[0036] Figure 14 is a flowchart illustrating a process of transmitting and receiving a side link signal by a UE in a wireless communication system according to an embodiment of the present disclosure;

[0037] Figure 15 is a flowchart illustrating a process in which a UE performs sidelink communication in a wireless communication system according to an embodiment of the present disclosure;

[0038] Figure 16 An example of the structure of a side link resource pool in a wireless communication system according to an embodiment of the present disclosure is shown;

[0039] Figure 17 Another example of the structure of a side link resource pool in a wireless communication system according to an embodiment of the present disclosure is shown;

[0040] Figure 18 An example of a sidelink hybrid automatic repeat request (HARQ) operation method in a wireless communication system according to an embodiment of the present disclosure is shown;

[0041] Figure 19 Another example of a sidelink HARQ operation method in a wireless communication system according to an embodiment of the present disclosure is shown; and

[0042] Figure 20 An example of a method of using an area identifier (ID) in a wireless communication system according to an embodiment of the present disclosure is shown.

[0043] Throughout the drawings, like reference numerals will be understood to refer to like parts, components and structures. DETAILED DESCRIPTION

[0044] The following description is provided with reference to the accompanying drawings to facilitate a comprehensive understanding of the various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to aid understanding, but these are merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications may be made to the various embodiments described herein without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and configurations may be omitted for clarity and brevity.

[0045] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but are merely used by the inventor to enable a clear and consistent understanding of the present disclosure. Therefore, it should be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustration purposes only and not for the purpose of limiting the present disclosure as defined by the appended claims and their equivalents.

[0046] It is to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.

[0047] Hereinafter, various embodiments of the present disclosure will be described based on a hardware method. However, various embodiments of the present disclosure include technologies using both hardware and software, and therefore various embodiments of the present disclosure may not exclude the software aspect.

[0048] The present disclosure described below relates to a device and method for selecting resources in a wireless communication system. More specifically, the present disclosure relates to selecting transmission resources for a UE to perform sidelink communication between UEs, and to a method and device for selecting at least one resource pool for communication when multiple resource pools for sidelink communication are configured.

[0049] The terms related to signals, channels, control information, network entities, and device elements used in the following description are merely used for convenience of description. Therefore, the present disclosure is not limited to those terms, and other terms with the same technical meaning may be used.

[0050] In the following description, the terms "physical channel" and "signal" may be used interchangeably with "data" or "control signal." For example, "Physical Downlink Shared Channel (PDSCH)" is a term used to refer to a physical channel used to transmit data, but it can also be used to refer to data. That is, in this disclosure, the expression "transmitting a physical channel" may be interpreted as being equivalent to the expression "transmitting data or a signal via a physical channel."

[0051] In this disclosure, "high-layer signaling" refers to a method for sending signals from a base station to a user equipment terminal (UE) via a downlink data channel of the physical layer, or from a user equipment terminal to a base station (UE) via an uplink data channel of the physical layer. High-layer signaling can be understood as radio resource control (RRC) signaling or medium access control (MAC) control elements (CEs).

[0052] In addition, in the present disclosure, the expression "greater than" or "less than" may be used to indicate whether a specific condition is satisfied or achieved, but is only used to indicate examples and does not exclude "greater than or equal to" or "equal to or less than." A condition indicating "greater than or equal to" may be replaced with "greater than," a condition indicating "equal to or less than" may be replaced with "less than," and a condition indicating "greater than or equal to and less than" may be replaced with "greater than and less than or equal to."

[0053] In addition, the present disclosure uses terminology used in some communication standards (eg, the 3rd Generation Partnership Project (3GPP)) to describe various embodiments, but this is only an example. Various embodiments can be easily modified and applied to other communication systems.

[0054] In the present disclosure, a transmitting UE is a UE that transmits sidelink data and control information or a UE that receives sidelink feedback information. In addition, in the present disclosure, a receiving UE is a UE that receives sidelink data and control information or a UE that transmits sidelink feedback information.

[0055] In this disclosure, PSFCH, PSCCH, and PSSCH included in this disclosure refer to physical channels of NR or LTE and are not limited to any one.

[0056] Figure 1 A wireless communication system according to an embodiment of the present disclosure is shown.

[0057] refer to Figure 1 , which shows BS 110, UE 120 and UE 130 as some nodes using a radio channel in a wireless communication system. Figure 1 Only one BS is shown, but another BS that is the same as or similar to BS 110 may also be included.

[0058] BS 110 is a network infrastructure element that provides radio access to UEs 120 and 130. BS 110 has a coverage area defined in a predetermined geographic area based on the range within which signals can be transmitted and received. BS 110 may be referred to as an "access point (AP)", "eNodeB (eNB)", "fifth generation (5G) node", "g NodeB (next generation NodeB (gNB))", "radio point", "transmission / reception point (TRP)", or another term having a technically equivalent meaning thereof, as well as a "base station".

[0059] Each of UE 120 and UE 130 is a device used by a user and communicates with BS 110 via a radio channel. The link from BS 110 to UE 120 or UE 130 is called a downlink (DL), and the link from UE 120 or UE 130 to BS 110 is called an uplink (UL). UE 120 and UE 130 communicate with each other via a radio channel. In this case, the link between UE 120 and UE 130 is called a sidelink, and the sidelink can be used interchangeably with the PC-5 interface. Depending on the situation, at least one of UE 120 or UE 130 can operate without any user involvement. That is, at least one of terminals 120 or 130 can be a device that performs machine type communication (MTC) and may not be carried by a user. Each of UE 120 and UE 130 may be referred to as a “user equipment (UE)”, a “mobile station”, a “subscriber station”, a “remote terminal”, a “wireless terminal” or a “user device”, or another term having an equivalent technical meaning, as well as a “terminal”.

[0060] BS 110, UE 120, and UE 130 can transmit and receive wireless signals in the millimeter wave (mmWave) frequency band (e.g., 28 GHz, 30 GHz, 38 GHz, or 60 GHz). At this time, in order to improve channel gain, BS 110, UE 120, and UE 130 can perform beamforming. Beamforming can include transmit beamforming and receive beamforming. That is, BS 110, UE 120, and UE 130 can assign directionality to transmitted or received signals. To this end, BS 110 and UEs 120 and 130 can select serving beams 112, 113, 121, and 131 through a beam search process or a beam management process. After selecting serving beams 112, 113, 121, and 131, communication can be performed through resources that have a quasi-co-location (QCL) relationship with the resources that transmit serving beams 112, 113, 121, and 131.

[0061] If a large-scale characteristic of a channel used to transmit symbols through a first antenna port can be inferred from a channel used to transmit symbols through a second antenna port, then it can be assessed that a QCL relationship exists between the first antenna port and the second antenna port. For example, the large-scale characteristic may include at least one of delay spread, Doppler spread, Doppler shift, average gain, average delay, or spatial receiver parameters.

[0062] Figure 2 A configuration of a BS in a wireless communication system according to an embodiment of the present disclosure is shown.

[0063] Figure 2The illustrated configuration may be understood as the configuration of BS 110. The suffix "-unit" or "-device" used hereinafter may refer to a unit for processing at least one function or operation and may be implemented as hardware, software, or a combination of hardware and software.

[0064] refer to Figure 2 , the BS includes a wireless communication unit 210 , a backhaul communication unit 220 , a storage unit 230 , and a controller 240 .

[0065] Wireless communication unit 210 performs functions for transmitting and receiving signals over radio channels. For example, wireless communication unit 210 converts baseband signals into bitstreams according to the system's physical layer standard. For example, when transmitting data, wireless communication unit 210 generates complex symbols by encoding and modulating the transmitted bitstream. When receiving data, wireless communication unit 210 reconstructs the received bitstream by demodulating and decoding the baseband signal.

[0066] The wireless communication unit 210 up-converts the baseband signal into a radio frequency (RF) band signal, transmits the RF band signal through the antenna, and down-converts the RF band signal received through the antenna into a baseband signal. To this end, the wireless communication unit 210 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), etc. In addition, the wireless communication unit 210 may include multiple transmit / receive paths. In addition, the wireless communication unit 210 may include at least one antenna array, wherein the antenna array includes multiple antenna elements.

[0067] In terms of hardware, the wireless communication unit 210 may include a digital unit and an analog unit, and the analog unit may include multiple subunits according to operating power, operating frequency, etc. The digital unit may be implemented by at least one processor, such as a digital signal processor (DSP).

[0068] Wireless communication unit 210 transmits and receives signals, as described above. Therefore, all or part of wireless communication unit 210 may be referred to as a "transmitter," "receiver," or "transceiver." Furthermore, in the following description, transmission and reception performed via a radio channel may include the aforementioned processing of wireless communication unit 210.

[0069] The backhaul communication unit 220 provides an interface for communicating with other nodes within the network. That is, the backhaul communication unit 220 converts a bit stream transmitted from the BS to another node (e.g., another access node), another BS, a higher-layer node, or a core network into a physical signal, and converts a physical signal received from another node into a bit stream.

[0070] The storage unit 230 may store data such as basic programs, applications, and configuration information for the operation of the BS. The storage unit 230 may include a volatile memory, a nonvolatile memory, or a combination of a volatile memory and a nonvolatile memory. The storage unit 230 provides the stored data in response to a request from the controller 240.

[0071] The controller 240 can control the overall operation of the BS. For example, the controller 240 sends and receives signals through the wireless communication unit 210 or the backhaul communication unit 220. The controller 240 records data in the storage unit 230 and reads the recorded data. The controller 240 can also perform the functions of the protocol stack required by the communication standard. According to another embodiment, the protocol stack can be included in the wireless communication unit 210. To this end, the controller 240 can include at least one processor. According to various embodiments, the controller 240 can control the BS to perform operations according to the various embodiments described below.

[0072] Figure 3 The configuration of a UE in a wireless communication system according to an embodiment of the present disclosure is shown.

[0073] Figure 3 The configuration shown may be understood as the configuration of UE 120 . Figure 3 The illustrated configuration may be similarly understood as the configuration of UE 130. The suffix "-unit" or "-device" used hereinafter may refer to a unit for processing at least one function or operation and may be implemented as hardware, software, or a combination of hardware and software.

[0074] refer to Figure 3 , the UE includes a communication unit 310, a storage unit 320 and a controller 330.

[0075] The communication unit 310 performs functions for transmitting and receiving signals via a radio channel. For example, the communication unit 310 performs conversion functions between baseband signals and bit streams according to the physical layer standard of the system. For example, during data transmission, the communication unit 310 generates complex symbols by encoding and modulating the transmitted bit stream. During data reception, the communication unit 310 reconstructs the received bit stream by demodulating and decoding the baseband signal. In addition, the communication unit 310 up-converts the baseband signal into an RF band signal, transmits the RF band signal via an antenna, and then down-converts the RF band signal received via the antenna into a baseband signal. For example, the communication unit 310 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC, and an ADC.

[0076] The communication unit 310 may include multiple transmit / receive paths. The communication unit 310 may include at least one antenna array including multiple antenna elements. In terms of hardware, the communication unit 310 may include digital circuits and analog circuits (e.g., radio frequency integrated circuits (RFICs)). The digital circuits and analog circuits may be implemented as a single package. The communication unit 310 may include multiple RF chains. The communication unit 310 may perform beamforming.

[0077] The communication unit 310 transmits and receives signals as described above. Therefore, all or some of the communication unit 310 may be referred to as a "transmitter," a "receiver," or a "transceiver." In the following description, transmission and reception performed through a radio channel are used to include the processing performed by the communication unit 310.

[0078] The storage unit 320 stores data such as basic programs, applications, and configuration information for UE operation. The storage unit 320 may include volatile memory, non-volatile memory, or a combination of volatile and non-volatile memory. The storage unit 320 provides the stored data in response to a request from the controller 330.

[0079] The controller 330 controls the overall operation of the UE. For example, the controller 330 sends and receives signals through the communication unit 310. The controller 330 records data in the storage unit 320 and reads the recorded data. The controller 330 can perform the functions of the protocol stack required by the communication standard. To this end, the controller 330 may include at least one processor or microprocessor, or may be part of a processor. In addition, the communication unit 310 or that part of the controller 330 may be referred to as a communication processor (CP). According to various embodiments, the controller 330 may control the UE to perform operations according to the various embodiments described below.

[0080] Figure 4 The configuration of a communication unit in a wireless communication system according to an embodiment of the present disclosure is shown.

[0081] Figure 4 Shown Figure 2 The wireless communication unit 210 or Figure 3 An example of a detailed configuration of the wireless communication unit 310. Specifically, Figure 4 Shown as Figure 2 The wireless communication unit 210 or Figure 3 An element for performing beamforming as part of the wireless communication unit 310 .

[0082] refer to Figure 4, the wireless communication unit 210 or the communication unit 310 includes a coding and modulation unit 402 , a digital beamforming unit 404 , a plurality of transmission paths 406 - 1 to 406 -N, and an analog beamforming unit 408 .

[0083] The coding and modulation unit 402 performs channel coding. For channel coding, at least one of a low-density parity check (LDPC) code, a convolutional code, and a polar code may be used. The coding and modulation unit 402 generates modulation symbols by performing constellation mapping.

[0084] The digital beamforming unit 404 performs beamforming on a digital signal (e.g., a modulation symbol). To this end, the digital beamforming unit 404 multiplies the modulation symbol by a beamforming weight. The beamforming weight value can be used to change the magnitude and phase of the signal and can be referred to as a "precoding matrix" or "precoder." The digital beamforming unit 404 outputs the digitally beamformed modulation symbols through multiple transmission paths 406-1 to 406-N. At this time, according to a multiple-input multiple-output (MIMO) transmission scheme, the modulation symbols can be multiplexed, or the same modulation symbol can be provided to multiple transmission paths 406-1 to 406-N.

[0085] Multiple transmission paths 406-1 to 406-N convert the digital signals of digital beamforming into analog signals. To this end, each of the multiple transmission paths 406-1 to 406-N can include an inverse fast Fourier transform (IFFT) calculator, a cyclic prefix (CP) inserter, a DAC, and an up-converter. The CP inserter is used for an orthogonal frequency division multiplexing (OFDM) scheme and can be omitted when another physical layer scheme (e.g., filter bank multi-carrier (FBMC)) is applied. In other words, the multiple transmission paths 406-1 to 406-N provide independent signal processing processes for the multiple streams generated by digital beamforming. However, according to one embodiment, some elements of the multiple transmission paths 406-1 to 406-N can be shared.

[0086] The analog beamforming unit 408 performs beamforming on the analog signal. To this end, the digital beamforming unit 404 multiplies the analog signal by the beamforming weight. The beamforming weight is used to change the magnitude and phase of the signal. Specifically, the analog beamforming unit 440 can be configured differently depending on the connection structure between the multiple transmission paths 406-1 to 406-N and the antenna. For example, each of the multiple transmission paths 406-1 to 406-N can be connected to an antenna array. In another example, the multiple transmission paths 406-1 to 406-N can be connected to an antenna array. In another example, the multiple transmission paths 406-1 to 406-N can be adaptively connected to an antenna array, or two or more antenna arrays.

[0087] Figure 5A An example of a scenario of sidelink communication in a wireless communication system according to an embodiment of the present disclosure is shown.

[0088] Figure 5B An example of a scenario of sidelink communication in a wireless communication system according to an embodiment of the present disclosure is shown.

[0089] Figure 5C An example of a scenario of sidelink communication in a wireless communication system according to an embodiment of the present disclosure is shown.

[0090] Figure 5D An example of a scenario of sidelink communication in a wireless communication system according to an embodiment of the present disclosure is shown.

[0091] Figure 5A 1 shows a scenario in which sidelink UEs 520a and 520b are within the coverage of BS 510. Sidelink UEs 520a and 520b can receive data and control information from BS 510 via a downlink (DL) or transmit data and control information to the BS via an uplink (UL). The data and control information can be data and control information for sidelink communication and data and control information for general cellular communication rather than sidelink communication.

[0092] refer to Figure 5A , sidelink UEs 520a and 520b may send and receive data and control information for sidelink communication via the sidelink.

[0093] Figure 5B 10. A partial coverage scenario is shown, where a first UE 520a among the sidelink UEs is located within the coverage of the BS 510 and a second UE 520b is located outside the coverage of the BS 510. The first UE 520a, located within the coverage of the BS 510, can receive data and control information from the BS via a downlink or transmit data and control information to the BS via an uplink. The second UE 520b, located outside the coverage of the BS 510, cannot receive data and control information from the BS via a downlink or cannot transmit data and control information to the BS via an uplink. The second UE 520b can transmit and receive data and control information for sidelink communication to and from the first UE 520a via a sidelink.

[0094] Figure 5CThe figure shows a case where sidelink UEs (e.g., first UE 520a and second UE 520b) are located outside the coverage of BS 510. Therefore, first UE 520a and second UE 520b cannot receive data and control information from the BS via a downlink and cannot transmit data and control information to the BS via an uplink. First UE 520a and second UE 520b can transmit and receive data and control information for sidelink communication via a sidelink.

[0095] Figure 5D The following illustrates a case of inter-cell sidelink communication, in which a first UE 520a and a second UE 520b performing sidelink communication access different BSs (e.g., a first BS 510a and a second BS 510b) (e.g., in an RRC connected state) or camp on them (e.g., in an RRC connection released state, i.e., an RRC idle state). In this case, the first UE 520a can be a sidelink transmitting UE, and the second UE 520b can be a sidelink receiving UE. Alternatively, the first UE 520a can be a sidelink receiving UE, and the second UE 520b can be a sidelink transmitting UE. The first UE 520a can receive a sidelink-specific system information block (SIB) from the BS 510 to which the first UE 520a accesses (or on which the first UE 520a camps), and the second UE 520b can receive a sidelink-specific SIB from another BS 510b to which the second UE 520b accesses (or on which the second UE 520b camps). At this time, information about the sidelink-specific SIB received by the first UE 520a may be different from information about the sidelink-specific SIB received by the second UE 520b. Therefore, unified information may be required to perform sidelink communication between UEs located in different cells.

[0096] refer to 5A to 5D Although a sidelink system including two UEs (e.g., a first UE 510a and a second UE 520b) has been described, the present disclosure is not limited thereto and may be applied to a sidelink system in which three or more UEs participate. The uplink and downlink between the BS 510 and the sidelink UEs may be referred to as Uu interfaces, and the sidelink between the sidelink UEs may be referred to as a PC-5 interface. Hereinafter, uplink or downlink, Uu interface, sidelink, and PC-5 may be used interchangeably.

[0097] Meanwhile, in the present disclosure, a UE may be a vehicle supporting vehicle-to-vehicle (V2V) communication, a vehicle supporting vehicle-to-pedestrian (V2P) communication or a pedestrian's mobile phone (i.e., a smartphone), a vehicle supporting vehicle-to-network (V2N) communication, or a vehicle supporting vehicle-to-infrastructure (V2I) communication. In the present disclosure, a UE may be a roadside unit (RSU) with UE functionality, an RSU with base station functionality, or an RSU with some base station functionality and some UE functionality.

[0098] Figure 6A An example of a sidelink communication transmission scheme in a wireless communication system according to an embodiment of the present disclosure is shown.

[0099] Figure 6B An example of a sidelink communication transmission scheme in a wireless communication system according to an embodiment of the present disclosure is shown.

[0100] Figure 6A A unicast scenario is shown and Figure 6B A multicast scenario is shown.

[0101] refer to Figure 6A , the sending UE 620a and the receiving UE 620b can perform one-to-one communication. Figure 6A The transmission scheme shown may be referred to as unicast communication.

[0102] refer to Figure 6B , the sending UE 620a or 620d and the receiving UEs 620b, 620c, 620e, 620f and 620g can perform one-to-many communication. Figure 6B The transmission scheme shown may be referred to as multicast or multicast. Figure 6B , a first UE 620a, a second UE 620b, and a third UE 620c form one group and perform multicast communication, and a fourth UE 620d, a fifth UE 620e, a sixth UE 620f, and a seventh UE 620g form another group and perform multicast communication. A UE can perform multicast communication within the group to which the UE belongs and can perform unicast, multicast, or broadcast communication with at least one other UE belonging to another group. Although Figure 6B Two groups are shown, but the present disclosure is not limited thereto and may be applied to a case where a large number of groups are formed.

[0103] At the same time, although Figure 6A or Figure 6B Although not shown in FIG, the sidelink UE may perform broadcast communication. Broadcast communication is a scheme in which all sidelink UEs receive data and control information transmitted by the sidelink transmitting UE via the sidelink. For example, when the first UE 620a is Figure 6BWhen the sending UE 620a is connected, the remaining UEs 620b, 620c, 620d, 620e, 620f and 620g can receive the data and control information sent by the first UE 620a.

[0104] Sidelink unicast communication, multicast communication, and broadcast communication can be supported in in-coverage scenarios, partial coverage scenarios, or out-of-coverage scenarios.

[0105] Unlike the LTE side link, the NR side link can consider supporting transmission types in which a vehicle UE sends data only to one specific UE via unicast and transmission types in which a vehicle UE sends data to multiple specific UEs via multicast. For example, when considering service scenarios such as smart convoys, which enable two or more vehicles to be connected via a network and move in a cluster, unicast and multicast technologies can be useful. Specifically, unicast communication can be used to control one specific UE by a leader UE in a group connected via a smart convoy, while multicast communication can be used to control a group including multiple specific UEs.

[0106] In the sidelink system, resource allocation can follow Mode 1 or Mode 2 below.

[0107] (1) Resource allocation in Mode 1

[0108] Mode 1 is a scheme based on scheduled resource allocation performed by the BS. More specifically, in the resource allocation in Mode 1, the BS can allocate resources for sidelink transmission to the RRC-connected UE according to a dedicated scheduling scheme. Since the BS can manage the resources of the sidelink, scheduled resource allocation is beneficial for managing interference and resource pools (e.g., dynamic allocation and / or semi-static transmission). When an RRC-connected mode UE has data to send to another UE, the UE can send information to the BS via an RRC message or a MAC control element indicating that the UE has data to send to the other UE. For example, the RRC message indicating the presence of data can be a Sidelink UE Information (SidelinkUEInformation) message or a UE Assistance Information (UEAssistanceInformation) message. For example, the MAC control element indicating the presence of data can be a Buffer Status Report (BSR) MAC control element for sidelink communication or a Scheduling Request (SR). The Buffer Status Report includes at least one of an indicator indicating the BSR or information about the size of buffered data for sidelink communication. Since the BS schedules resources to the sidelink transmitting UE when applying Mode 1, Mode 1 can only be applied when the sidelink transmitting UE is within the coverage of the BS.

[0109] (2) Resource allocation in Mode 2

[0110] Mode 2 is a scheme based on UE autonomous resource selection, in which the sidelink transmitting UE selects resources. Specifically, according to Mode 2, the BS provides the UE with a sidelink transmit / receive resource pool for the sidelink through system information or an RRC message (e.g., an RRC reconfiguration (RRCReconfiguration) message or a PC-5RRC message) and the transmitting UE selects the resource pool and resources according to predetermined rules. Since the BS provides the configuration information of the sidelink resource pool, Mode 2 can be used when the sidelink UE is within the coverage of the BS. When the sidelink UE is outside the coverage of the BS, the sidelink UE can perform operations according to Mode 2 in a pre-configured resource pool. For example, as a UE autonomous selection method, area mapping, sensing-based resource selection, or random selection can be used.

[0111] (3) Others

[0112] In addition, even if the UE is within the coverage of the BS, scheduled resource allocation, resource allocation in the UE autonomous resource selection mode, or resource selection may not be performed. In this case, the UE can perform sidelink communication through a pre-configured resource pool.

[0113] Figure 7 An example of a link related to side link communication in a wireless communication system according to an embodiment of the present disclosure is shown.

[0114] refer to Figure 7 , side link communication can be performed through at least one of the following links.

[0115] The link between the NR sidelink UE 720a and the other NR sidelink UE 720c may be referred to as an NR sidelink. The NR sidelink UE 720a may transmit sidelink control information and data information for NR sidelink communication to the other NR sidelink UE 720c via the NR sidelink. In addition, the NR sidelink UE 720a may receive sidelink control information and data information for NR sidelink communication from the other NR sidelink UE 720c via the NR sidelink.

[0116] The link between the NR sidelink UE 720a and the LTE sidelink UE 720b may be referred to as an LTE sidelink. When the NR sidelink UE 720a is capable of supporting LTE sidelink communication, the NR sidelink UE 720a may send or receive control information and data information for LTE sidelink communication via the LTE sidelink.

[0117] The downlink or uplink between the NR sidelink UE 720a and the NR BS 710b may be referred to as NR Uu. The NR BS 710b may be referred to as a gNB.

[0118] The NR sidelink UE 720a may receive control information and data information related to NR sidelink transmission and reception from the gNB 710b via NR Uu. The NR sidelink UE 720a may transmit NR sidelink control information and data information received from another NR sidelink UE 720c to the gNB via NR Uu.

[0119] The NR sidelink UE 720a may receive control information and data information related to LTE sidelink transmission and reception from the NR BS 710b via NR Uu. The NR sidelink UE 720a may transmit the LTE sidelink control information and data information received from the LTE sidelink UE 720b to the gNB via NR Uu. It may be assumed that the NR sidelink UE 720a has the capability to support LTE sidelink communication.

[0120] The downlink or uplink between the NR sidelink UE 720a and the LTE BS 710a may be referred to as LTE Uu. The LTE BS 710a may be referred to as an eNB.

[0121] The NR sidelink UE 720a may receive control information and data information related to NR sidelink transmission and reception from the LTE BS 710a via LTE Uu. The NR sidelink UE 720a may transmit NR sidelink control information and data information received from another NR sidelink UE 720c to the eNB 710a via LTE Uu. In this case, it may be assumed that the NR sidelink UE 720a has the capability to support LTE Uu.

[0122] The NR sidelink UE 720a may receive control information and data information related to LTE sidelink transmission and reception from the LTE BS 710a via the LTE Uu. The NR sidelink UE 720a may transmit the LTE sidelink control information and data information received from the LTE sidelink UE 720b to the LTE BS 710a via the LTE Uu. It may be assumed that the NR sidelink UE 720a has both the capability to support LTE sidelink communication and the capability to support LTE Uu.

[0123] Depending on the NR sidelink UE’s capabilities, Figure 7 The various link classifications for NR sidelink communications are shown in Table 1.

[0124] [Table 1]

[0125]

[0126] Figure 8An example of a protocol stack of a sidelink UE in a wireless communication system according to an embodiment of the present disclosure is shown.

[0127] refer to Figure 8 , the application layer of the first UE 820a and the second UE 820b may perform service discovery. Service discovery may include discovery indicating the sidelink communication scheme (e.g., unicast, multicast, or broadcast) to be performed by each UE. Figure 8 In the example of FIG, it can be assumed that the first UE 820a and the second UE 820b will perform a unicast communication scheme after performing a service discovery process in the application layer. The first UE 820a and the second UE 820b can obtain information about a source identifier (ID) and a destination identifier (ID) for sidelink communication through the service discovery process.

[0128] When the service discovery process is complete, you can Figure 8 The direct link setup process between UEs is performed in the PC-5 signaling protocol layer shown in FIG. At this time, security configuration information for direct communication between the first UE 820a and the second UE 820b can be sent and received. When the direct link connection setup is completed, the PC-5 radio resource control (RRC) setup process can be performed in the PC-5 signaling protocol layer shown in FIG. Figure 8 At this point, the UE capability information of the first UE 820a and the second UE 820b may be exchanged, and access stratum (AS) layer parameter information for unicast communication may be exchanged. When the PC-5 RRC establishment process is complete, the first UE 820a and the second UE 820b may perform unicast communication.

[0129] In the above example, although unicast communication is provided as an example, the communication can be extended to multicast communication. For example, when the first UE 820a, the second UE 820b and Figure 8 When a third UE (not shown) performs multicast communication, the first UE 820a and the second UE 820b can perform service discovery for unicast communication, establish a direct link between the UEs, and the PC-5 RRC establishment procedure described above. Furthermore, the first UE 820a and the third UE can perform service discovery for unicast communication, establish a direct link between the UEs, and the PC-5 RRC establishment procedure. Finally, the second UE 820b and the third UE can perform service discovery for unicast communication, establish a direct link between the UEs, and the PC-5 RRC establishment procedure. In other words, a pair of transmitting and receiving UEs participating in multicast communication can perform the PC-5 RRC establishment procedure for unicast communication, rather than a separate PC-5 RRC establishment procedure for multicast communication.

[0130] The PC-5 RRC establishment process for unicast or multicast communication can be performed by Figure 6A and Figure 6B When there is a UE that desires to perform unicast or multicast communication within the coverage of the BS, the corresponding UE may perform a PC-5 RRC establishment procedure before or after performing downlink or uplink synchronization with the BS.

[0131] Figure 9 An example of a sidelink resource pool in a wireless communication system according to an embodiment of the present disclosure is shown.

[0132] Figure 9 A sidelink resource pool is shown.

[0133] refer to Figure 9 , the sidelink resource pool may include K time slots 910 on the time axis and M resource blocks (RBs) 920 on the frequency axis. The M resource blocks 920 may form at least one resource block group (RBG) or at least one subchannel. A time slot may include one or more OFDM symbols and a maximum of 14 OFDM symbols. A resource block may include 12 subcarriers, and a resource block group may include m resource blocks. Similarly, a subchannel may include m resource blocks. A resource block may be referred to as a "frequency block."

[0134] According to one embodiment, a resource block group or a subchannel can be the minimum unit of sidelink resource allocation. That is, the sidelink transmitting UE can send sidelink control information, sidelink data information or sidelink feedback information through at least one or more resource block groups or one subchannel. At this time, the resource block group or subchannel used to send sidelink control information, the resource block group or subchannel used to send and receive sidelink data information, and the resource block group or subchannel used to send and receive sidelink feedback information may include different numbers of resource blocks. For example, a resource block group or subchannel used to send sidelink control information may include 2 resource blocks, and a resource block group or subchannel used to send sidelink data information may include 4 resource blocks. The resource block group or subchannel used to send sidelink feedback information may include 1 resource block.

[0135] According to one embodiment, sidelink UEs may perform sidelink transmission or reception using different numbers of resource block groups or subchannels. In other words, UEs using the same or different resource pools may use different numbers of resource block groups or subchannels to transmit or receive sidelink data. For example, a first UE may perform sidelink transmission or reception using two sidelink resource block groups or subchannels, and a second UE may perform sidelink transmission or reception using four sidelink resource block groups or subchannels.

[0136] The sidelink UE can obtain information about how many time slots are included in one sidelink resource pool and how many OFDM symbols are included in one time slot on the time axis, and how many resource blocks (or resource block groups or subchannels) are included in the sidelink resource pool and how many resource blocks are included in one resource block group (or subchannel) on the frequency axis. Information about the configuration of the sidelink resource pool, time slots, and resource blocks can be obtained by at least one of the following methods:

[0137] ● Using pre-configured values ​​in the UE;

[0138] ●Configuration values ​​in the UE via system information and RRC signaling from the BS;

[0139] ● configuring the value in the UE via PC-5 RRC signalling; and

[0140] • Always use a fixed value (eg, one slot includes 14 OFDM symbols).

[0141] exist Figure 9 In the example of , the K time slots can be physically or logically contiguous on the time axis. When the K time slots are logically contiguous, the time slots may be physically discontiguous. Similarly, the M resources can be physically or logically contiguous frequency resource blocks on the frequency axis. When the M resource blocks are logically contiguous, the resource blocks may be physically discontiguous.

[0142] Although Figure 9 Not shown, the side link transmission UE can use Figure 9 The side link resource pool is used to send side link control information or data information. In this case, the side link resource pool can be called a transmission resource pool. In addition, the side link receiving UE can use Figure 9 In this case, the side link resource pool may be referred to as a receiving resource pool. In another example, the side link receiving UE may use Figure 9 The side link resource pool is used to send side link feedback information to the side link sending UE, and the side link sending UE can use Figure 9 In this case, the side link resource pool may be referred to as a side link feedback resource pool.

[0143] The transmit resource pool and receive resource pool can be configured independently or pre-configured. For example, a sidelink UE can configure a transmit resource pool consisting of K1 time slots and M1 resource blocks and a receive resource pool consisting of K2 time slots and M2 resource blocks, or the configuration can be pre-configured. For example, K1 ≤ K2 and M1 ≤ M2. The transmit resource pool can be a subset of the receive resource pool.

[0144] In another example, the sidelink UE may be configured with one or more transmit resource pools or one or more receive resource pools, or may be pre-configured to support various services. More specifically, when two transmit resource pools are configured or pre-configured, the first transmit resource pool may be used for sidelink unicast transmission, and the second transmit resource pool may be used for sidelink broadcast transmission. When two receive resource pools are configured or pre-configured, the first receive resource pool may be used for sidelink unicast reception, and the second receive resource pool may be used for sidelink multicast reception.

[0145] In another example, despite unicast transmission or reception, different transmission resource pools or reception resource pools may have been configured or may be pre-configured depending on requirements such as the presence or absence of a sidelink feedback channel or delay time (latency) required for sidelink communication.

[0146] In the above examples, the number of transmission resource pools and the number of reception resource pools configured or preconfigured in the UE may be different.

[0147] Figure 10 An example of a side link frame structure in a wireless communication system according to an embodiment of the present disclosure is shown.

[0148] Although Figure 10 The system is shown as operating 1024 radio frames, but the present disclosure is not limited thereto. For example, a specific system may operate a greater or lesser number of radio frames than 1024 radio frames, and the number of radio frames operated by the system may be configured in the UE via a Master Information Block (MIB) transmitted by the BS via the Physical Broadcast Channel (PBCH), or may be a fixed value specified by the UE. Alternatively, the number of radio frames operated may be configured by the UE's PC-5 RRC or may be pre-configured.

[0149] refer to Figure 10 , the radio frame number and the system frame number can be processed in the same manner. That is, the radio frame number "0" can correspond to the system frame number "0", and the radio frame number "1" can correspond to the system frame number "1". One radio frame can include ten subframes, and one subframe can have a length of 1ms on the time axis.

[0150] like Figure 10 As shown, the number of time slots included in one subframe may vary depending on the subcarrier spacing used for the sidelink. For example, when the sidelink communication uses a subcarrier spacing of 15 kHz, one subframe may include one time slot. However, when a subcarrier spacing of 30 kHz and a subcarrier spacing of 60 kHz are used, one subframe may include two time slots and four time slots, respectively. Figure 10This is not shown in the figure, but this can be applied when using a subcarrier spacing of 120 kHz or more. That is, when the number of time slots included in one subframe is summarized, as the subcarrier spacing increases to 15 kHz × 2 n , the number of time slots included in a subframe can be increased to 2 n At this time, n = 0, 1, 2, 3...

[0151] Figure 11 An example of allocation of timeline resources of a sidelink resource pool in a wireless communication system according to an embodiment of the present disclosure is shown.

[0152] On the time axis, the sidelink resource pool may be a set of time slots for transmitting and receiving sidelink control information, data information, and feedback information, and the allocation of timeline resources of the sidelink resource pool may be the start and end points of the set of time slots for performing sidelink transmission and reception. Specifically, the start point of the sidelink resource pool may include a time slot index or both a time slot index and a symbol index within the corresponding time slot.

[0153] Figure 11 Assume that the system uses a subcarrier spacing of 15 kHz (e.g., one radio frame consists of ten time slots, such as Figure 10 As shown in FIG, the side link resource pool starts from the time slot index “3” of the system frame “1” based on the system frame number “0”. The time slots available for side link transmission and reception starting from the time slot index “3” of the system frame “1” can be indicated in the form of a bitmap. In the case of a frequency division duplex (FDD) system, the time slot index “0” to the time slot index “9” can be Figure 10 By using a bitmap (7 bits) of 1100010 based on slot index "3", "1" may be a sidelink slot and "0" may be an uplink slot (i.e., slot index "3", slot index "4" and slot index "8" may be slots that can be used for sidelink transmission and reception). The 7-bit bitmap may be repeated, and thus, the sidelink slot may be represented as the last slot index up to system frame number 1023. For example, in Figure 10 In the example, there can be (1024-2)×10+7=10227 time slots, and the 10227 time slots can be represented by 1461 repetitions of the 7-bit bitmap.

[0154] In another example, an 8-bit bitmap can be used, and when the side link resource pool starts from the time slot index "3" of the system frame number "1", 10227 time slots can be represented by 1278 repetitions of the 8-bit bitmap. At this time, the last three time slots cannot be represented by the bitmap, and therefore the corresponding time slots can be excluded from the side link resource pool. Alternatively, it can be interpreted that the time slots corresponding to the 3 bits in the front part of the 8-bit bitmap can be included in the side link resource pool. For example, when the 8-bit bitmap corresponds to 10100111, the "101" in the front part can be included in the side link resource pool (that is, the time slot index "7" and the time slot index "9" of the system frame number 1023 are included in the side link resource pool).

[0155] In the above examples, a 7-bit or 8-bit bitmap is shown, but the present disclosure is not limited thereto.

[0156] Meanwhile, in case of a time division duplex (TDD) system, slot index '0' to slot index '9' may be Figure 10 In this case, the downlink time slot may not be reflected in the bitmap. For example, when slot index "6" and slot index "7" are Figure 10 When a downlink time slot is in the sidelink resource pool, the bitmap used to represent the sidelink time slot can be 5 bits of 11010. Since the 5-bit bitmap is repeated 2045 times and the last two time slots cannot be represented by the bitmap, it can be interpreted that the corresponding time slot is excluded from the sidelink resource pool or the time slot corresponding to the first 2 bits in the 5-bit bitmap is included in the sidelink resource pool.

[0157] In the above example, a 5-bit bitmap is shown, but the present disclosure is not limited thereto.

[0158] Figure 12 The sidelink unicast communication process in a wireless communication system according to an embodiment of the present disclosure is shown.

[0159] Figure 12 Signal exchanges between the BS 1210, the transmitting UE 1220a, and the receiving UE 1220b according to the sidelink communication procedure based on mode 1 resource allocation are shown.

[0160] refer to Figure 12In operation 1201, BS 1210 configures system parameters. BS 1210 may transmit parameters for sidelink communication to transmitting UE 1220a and receiving UE 1220b within the cell via system information. The system information may include a system information block (SIB) and may be transmitted periodically or on demand. For example, BS 1210 may transmit information regarding a sidelink bandwidth part (BWP) in which sidelink communication may be performed within its own cell and information regarding a sidelink resource pool that may be used for sidelink communication within the sidelink BWP.

[0161] In this case, the sidelink BWP can be configured independently of the uplink BWP (or downlink BWP), or can be included in the uplink BWP (or downlink BWP). When the sidelink BWP is included in the uplink BWP (or downlink BWP), the center frequency and bandwidth of the sidelink BWP can be included in the bandwidth of the uplink BWP (or downlink BWP). In addition, the sidelink resource pool within the sidelink BWP can refer to a transmit resource pool for sidelink transmission or a receive resource pool for sidelink reception.

[0162] At the same time, a sidelink BWP includes at least one sidelink resource pool, and the sidelink UE can receive the configuration of one or more resource pools from the BS. For example, the BS can configure unicast, multicast, and broadcast communications to be sent or received in different resource pools through system information. For example, resource pool A can be used for unicast transmission and reception, resource pool B can be used for multicast communication, and resource pool 3 can be used for broadcast communication transmission and reception. In another example, the BS can configure unicast, multicast, and broadcast communications to be performed in the same resource pool. In this case, different resource pools can be configured based on whether there are physical sidelink feedback channel (PSFCH) resources in the resource pool for sending sidelink feedback information. For example, resource pool A can be a pool in which PSFCH resources exist, and resource pool B can be a pool in which PSFCH resources do not exist. In this case, the transmission and reception of sidelink unicast and multicast data that requires hybrid automatic repeat request (HARQ) feedback can use resource pool A, and the transmission and reception of sidelink unicast and multicast data and broadcast data that do not require HARQ feedback can use resource pool B.

[0163] The information about the side link resource pool configured by the BS, configured by the PC-5 RRC, or pre-configured in the UE may include at least one item as shown in Table 2 below.

[0164] [Table 2]

[0165]

[0166]

[0167]

[0168]

[0169] As shown in Table 2, the parameter information is included in the configuration of the resource pool for sidelink communication, but the present disclosure is not limited thereto. That is, the information can be configured in the sidelink transmitting UE or the sidelink receiving UE independently of the configuration of the resource pool (for example, through different RRC parameter configurations).

[0170] Furthermore, when parameter information is included in the configuration of a resource pool for sidelink communication, different parameters can be configured depending on the sidelink communication method supported in the corresponding resource pool. For example, when unicast and multicast share the same resource pool, a single piece of resource pool configuration information can include both unicast parameter configuration information and multicast parameter configuration information, and each piece of parameter configuration information can be different from the other.

[0171] In operation 1203, the sending UE 1220a and the receiving UE 1220b establish a link. The sending UE 1220a and the receiving UE 1220b may send and receive at least one message for link setup. Through operation 1203, the sending UE 1220a and the receiving UE 1220b may obtain at least one of a source ID or a destination ID. For example, the sending UE 1220a and the receiving UE 1220b may perform a reference Figure 8 Describes the PC-5 RRC setup process.

[0172] In operation 1205, the transmitting UE 1220a recognizes the generation of sidelink data. The sidelink data may be generated by the application layer and transmitted to the lower layer. The content included in the sidelink data may vary depending on the application being executed. For example, when a vehicle-related application is being executed, the sidelink data may include information indicating the driving / operating status of the vehicle, information indicating the results of sensing the vehicle's surrounding environment, information requesting a specific operation to another vehicle, and information regarding warnings provided to neighboring vehicles or pedestrians.

[0173] In operation 1207, the transmitting UE 1220a transmits a scheduling request (SR) and / or a buffer status report (BSR) to the BS 1210. The transmitting UE 1220a may request sidelink resources for sidelink data to be transmitted to the receiving UE 1220b through the SR and / or BSR.

[0174] In operation 1209, BS 1210 transmits downlink control information (DCI) to transmitting UE 1220a. BS 1210, upon receiving the SR and / or BSR, may recognize that transmitting UE 1220a has data for sidelink transmission, determine resources required for sidelink transmission based on the SR and / or BSR, and transmit control information indicating the determined resources. For example, BS 1210 may transmit a sidelink scheduling grant to transmitting UE 1220a that includes at least one of resource information for sidelink control information (SCI) transmission, resource information for sidelink data transmission, and resource information for sidelink feedback information.

[0175] The sidelink scheduling grant is information used to authorize dynamic scheduling in the sidelink and can be a DCI sent via a physical downlink control channel (PDCCH). When BS 1210 is an NR BS, the sidelink scheduling grant may include information indicating the BWP for performing sidelink transmission and a carrier indicator field (CIF) or carrier frequency indicator indicating the carrier through which the sidelink transmission is performed. When BS 1210 is an LTE BS, the sidelink scheduling grant may include a CIF. In addition, the sidelink scheduling grant may also include feedback information for sidelink data, that is, resource allocation related information for the PSFCH that transmits acknowledgement (ACK) / negative ACK (NACK) information. When the sidelink transmission is multicast, the resource allocation information may include information for allocating multiple PSFCH resources to multiple UEs within the group. In addition, the resource allocation related information for the feedback information may be information indicating at least one of multiple feedback information resource candidate groups configured via higher-layer signaling. In operation 1211, transmitting UE 1220a transmits PSCCH / PSSCH to receiving UE 1220b. The transmitting UE 1220a receiving the sidelink scheduling grant sends an SCI for scheduling sidelink data according to the sidelink scheduling grant to the receiving UE 1220b through the PSCCH and sends the sidelink data through the PSSCH. The receiving UE 1220b receiving the SCI can receive the sidelink data sent through the PSSCH.

[0176] The SCI may include at least one of the following: resource allocation information for sidelink data transmission, modulation and coding scheme (MCS) information applied to sidelink data, group destination ID information, transmitter ID (source ID) information, unicast destination ID information, power control information for controlling sidelink power, timing advance (TA) information, DMRS configuration information for sidelink transmission, packet repetition transmission related information, such as information about the number of times a packet is repeatedly transmitted, information about resource allocation when repeatedly transmitting a packet, redundancy version (RV), or HARQ process ID. The SCI may also include feedback information for sidelink data, that is, information indicating the resources through which ACK / NACK information is transmitted.

[0177] In operation 1213, the receiving UE 1220b sends a PSFCH. The receiving UE 1220b sends ACK / NACK information indicating whether the decoding of the sidelink data is successful or failed to the sending UE 1220a via the PSFCH. The transmission of sidelink feedback information can be applied to unicast transmission or multicast transmission, but the present disclosure does not exclude broadcast transmission. When the sidelink transmission corresponds to multicast transmission, the corresponding UE receiving the multicast data can send feedback information through different PSFCH resources. Alternatively, the corresponding UE receiving the multicast data can send feedback information through the same PSFCH resource. In this case, only NACK information can be fed back. That is, in the case of ACK, the UE receiving the data may not send feedback. At this time, the PSFCH resources can include not only resources distinguished in the time domain or / and frequency domain, but also resources distinguished using codes, such as scrambling codes or orthogonal cover codes, and resources distinguished using different sequences and cyclic shifts applied to the sequences.

[0178] In operation 1215, the transmitting UE 1220a transmits a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH) to the BS 1210. The transmitting UE 1220a reports HARQ feedback to the BS 1210 via the PUCCH or PUSCH. The BS 1210 may configure the reporting of HARQ feedback received by the transmitting UE 1220a from the receiving UE 1220b through system information or RRC. In this case, the transmitting UE 1220a may transmit the sidelink HARQ feedback received from the receiving UE 1220b to the BS 1210 via the PUCCH or PUSCH. In addition, the BS 1210 may configure whether the transmitting UE 1220a multiplexes and transmits the sidelink HARQ feedback information received from the receiving UE 1220b with uplink control information (UCI) of the related field Uu.

[0179] When BS 1210 is configured to transmit sidelink HARQ feedback to BS 1210 via the PUCCH and does not multiplex the sidelink HARQ feedback information and UCI, transmitting UE 1220a cannot multiplex the sidelink HARQ feedback information and UU UCI to transmit them via a single PUCCH. In this case, BS 1201 can configure a PUCCH for transmitting sidelink HARQ feedback information independently of the PUCCH for transmitting UCI. In other words, the PUCCH for transmitting sidelink HARQ feedback information can exist independently, and any UCI can be transmitted in the corresponding PUCCH.

[0180] In contrast, when BS 1210 configures the transmission of sidelink HARQ feedback to BS 1210 via the PUCCH and multiplexing of the sidelink HARQ feedback information and UCI, transmitting UE 1220a may multiplex the sidelink HARQ feedback information and UCI to transmit them via a single PUCCH. Assuming that the sidelink HARQ feedback information consists of N1 bits and the UCI consists of N2 bits, the multiplexing order may follow N2+N1. In other words, the sidelink HARQ feedback information may be multiplexed after the UCI. When the code rate of the sum of the sidelink HARQ feedback bits and the UCI bits multiplexed and transmitted via the corresponding PUCCH is greater than the code rate configured by BS 1210, transmitting UE 1220a may forgo transmitting the sidelink HARQ feedback information. In other words, transmitting UE 1220a may discard the sidelink HARQ feedback information. In another example, the multiplexing order may follow N1+N2. In other words, the sidelink HARQ feedback information may be multiplexed after the UCI. At this time, when the code rate of N1+N2 is greater than the code rate configured by BS 1210, transmitting UE 1220a may abandon the transmission of UCI. In other words, transmitting UE 1220a may discard UCI.

[0181] In another example, whether transmitting UE 1220a forgoes sending sidelink HARQ feedback information or forgoes sending UCI can be determined based on priority. In this case, the priority can follow a preset rule based on the type of UCI. For example, a rule can be defined such that HARQ feedback information for downlink data has a higher priority than sidelink HARQ feedback information. A rule can also be defined such that feedback information for downlink CSI has a lower priority than sidelink HARQ feedback information. In this case, transmitting UE 1220a can forgo sending the information with the lower priority.

[0182] In another example of priority, whether to discard sidelink HARQ feedback information or discard UCI can be determined based on a priority index configured by a higher layer. For example, the transmitting UE 1220a can receive a priority index for sidelink data information corresponding to the sidelink HARQ feedback information from a higher layer, and a priority index for downlink UCI from a higher layer. The transmitting UE 1220a can compare the priority indexes and discard the information with the lower priority.

[0183] Figure 12 Assume the following scenario: the transmitting UE 1220a establishes an uplink connection with the BS 1210 (ie, is in the RRC connected state), and both the transmitting UE 1220a and the receiving UE 1220b are within the coverage of the BS 1210. Figure 12 Although not shown in FIG, when the transmitting UE 1220a has not established an uplink connection with the BS 1210 (ie, is in the RRC idle state), the transmitting UE 1220a may perform a random access procedure to establish an uplink connection with the BS 1210. Figure 12 Although not shown, in a scenario where the transmitting UE 1220a exists within the coverage of the BS 1210 and the receiving UE 1220b exists outside the coverage of the BS 1210, the receiving UE 1220b may receive configuration of information for side link communication in advance to use the configuration.

[0184] At the same time, if Figure 12 As shown, transmitting UE 1220a can receive a configuration of information for sidelink communication from BS 1210. When both transmitting UE 1220a and receiving UE 1220b are outside the coverage of BS 1210, transmitting UE 1220a and receiving UE 1220b can pre-receive a configuration of information for sidelink communication to use the configuration. In this case, pre-receiving a configuration can be interpreted as using a value embedded in the UE when the UE is released. In another example, when transmitting UE 1220a or receiving UE 1220b accesses BS 1210 and pre-acquires information about sidelink communication through RRC settings or has already acquired information about sidelink communication through system information of BS 1210, pre-receiving a configuration can refer to the most recently acquired information.

[0185] Although Figure 12 , but the sending UE 1220a and the receiving UE 1220b may utilize reference Figure 8The service discovery is completed by performing the described sidelink receiving UE, the direct link connection setup procedure between the UEs, and the PC-5 RRC setup procedure (e.g., operation 1203) before the operation of configuring system parameters from BS 1210 (e.g., operation 1201). That is, operation 1203 can be performed before operation 1201.

[0186] Figure 12 This example is for sidelink unicast communication with only one sidelink receiving UE, but can be applied to sidelink multicast communication and sidelink broadcast communication with multiple sidelink receiving UEs. However, in the case of sidelink broadcast communication, the process of the receiving UE sending the PSFCH to the transmitting UE or the process of the transmitting UE sending the PUCCH or PUSCH to the base station can be omitted.

[0187] At the same time, in the above reference Figure 7 In case 3) shown in FIG, the NR BS (e.g., gNB) can control both the NR side link and the LTE side link. More specifically, the NR serving cell can support both the NR side link and the LTE side link, and the NR UE can have the capability to support both the LTE side link and the NR side link. The UE can be in an RRC connected state with the NR BS and can request side link resources from the BS, such as Figure 12 As shown. At this time, the side link resources requested by the UE may be LTE side link resources or NR side link resources. The BS that receives information about the side link resource request from the UE may configure semi-persistent scheduling (PSP) resources for LTE side link and NR side link transmission through RRC. In addition, the BS may send a command for activating or releasing the SPS resources configured through RRC to the side link UE through DCI. In this case, the side link UE should identify that the DCI received by the UE from the BS refers to activation / release of SPS resources for NR side link transmission or activation / release of SPS resources for LTE side link transmission. At least one method in Table 3 below may be used by the side link UE to identify.

[0188] [Table 3]

[0189]

[0190]

[0191]

[0192] Meanwhile, the UE supporting case 3) defined in Table 1 above may have a modem for supporting the NR side link and a modem for supporting the LTE side link. At this time, as described above, when the side link UE receives DCI for controlling the LTE side link from the BS, the side link UE may be required to determine when the command of the DCI field should be executed based on the time point of receiving the corresponding DCI. For example, a fixed time point (i.e., 4ms) may be applied, and more specifically, a UE receiving DCI from the NR BS in time slot "n" may perform LTE side link transmission in an LTE subframe 4ms after time slot "n". However, there may be a delay time in the interface between the NR side link modem and the LTE side link modem, or the time between the two modems may not be synchronized. Therefore, there may be no LTE subframe 4ms after time slot "n". In this case, the UE may perform side link transmission in the LTE side link subframe that is first located 4ms later.

[0193] Depending on the situation, the first located LTE side link subframe may appear after tens of ms (for example, after 10ms). In this case, the UE cannot avoid unnecessarily storing the corresponding information to process the received DCI. In order to prevent inefficient use of the memory, the UE can operate with an offset from receiving the DCI from the BS to the LTE side link subframe to which the corresponding DCI is applied. More specifically, when the offset is 10ms, the UE can determine whether there is an LTE side link subframe from receiving the DCI to the offset (10ms). When there is an LTE side link subframe within the offset, the UE can send LTE side link control information and data information in the LTE side link subframe based on the DCI information received from the BS. On the other hand, when there is no LTE side link subframe within the offset, the UE can discard the DCI information received from the BS. That is, the UE can delete the DCI information from the memory and no longer store the DCI information in the memory. However, the operation can cause the transmission of the LTE side link to be abandoned by discarding the DCI information according to the configuration of the offset value and the pattern of the LTE side link traffic. For example, when the generation cycle of LTE side link traffic is long and the offset value is short, the transmission and reception of LTE side link data may be not smooth due to frequent DCI discarding. Therefore, the BS can insert the LTE side link subframe index into the DCI, and then send the DCI, and the side link UE should apply the corresponding DCI information to the LTE side link subframe index. The side link UE receiving the DCI can perform LTE side link transmission in the LTE side link subframe index indicated by the corresponding DCI. In another example, the BS can insert the offset into the DCI together with the LTE side link subframe, and then send the DCI, and the side link UE should apply the NR time slot for receiving the DCI and the corresponding DCI information to the LTE side link subframe. The side link UE receiving the DCI can perform LTE side link transmission in the LTE side link subframe located after the offset, and the offset is indicated by the DCI.

[0194] Figure 13 Another example of a unicast communication process in a wireless communication system according to an embodiment of the present disclosure is shown.

[0195] Figure 13 Signal exchanges between the BS 1310, the transmitting UE 1320a, and the receiving UE 1320b according to the sidelink communication procedure based on mode 2 resource allocation are shown.

[0196] refer to Figure 13In operation 1301, BS 1310 configures system parameters. BS 1310 may transmit parameters for sidelink communication to transmitting UE 1320a and receiving UE 1320b within the cell via system information. The system information may include SIBs and may be transmitted periodically or on demand. The parameters may include at least one of the parameters shown in Table 2. For example, BS 1310 may configure the sidelink BWP and one or more sidelink resource pools included in the sidelink BWP via system information. In this case, the sidelink BWP may be configured independently of the uplink BWP (or downlink BWP) or may be included in the uplink BWP. When the sidelink BWP is included in the uplink BWP (or downlink BWP), the center frequency and bandwidth of the sidelink BWP may be included in the bandwidth of the uplink BWP (or downlink BWP).

[0197] In operation 1303, the sending UE 1320a and the receiving UE 1320b establish a link. The sending UE 1320a and the receiving UE 1320b may send and receive at least one message for link setup. Through operation 1303, the sending UE 1320a and the receiving UE 1320b may obtain at least one of a source ID or a destination ID. For example, the sending UE 1320a and the receiving UE 1320b may perform a reference Figure 8 Describes the PC-5 RRC setup process.

[0198] Although Figure 13 , but the sending UE 1320a and the receiving UE 1320b may utilize reference Figure 8 The service discovery is completed by performing the described sidelink receiving UE, the direct link connection setup procedure between the UEs, and the PC-5 RRC setup procedure (e.g., operation 1303) before the operation of configuring system parameters from BS 1310 (e.g., operation 1301). That is, operation 1303 can be performed before operation 1301.

[0199] In operation 1305, the transmitting UE 1320a recognizes the generation of sidelink data. The sidelink data may be generated by the application layer and transmitted to the lower layer. The content included in the sidelink data may vary depending on the application being executed. For example, when a vehicle-related application is being executed, the sidelink data may include information indicating the driving / operating status of the vehicle, information indicating the results of sensing the vehicle's surrounding environment, information requesting a specific operation to another vehicle, and information regarding warnings provided to neighboring vehicles or pedestrians.

[0200] In operation 1307, the transmitting UE 1320a transmits a PSCCH / PSSCH to the receiving UE 1320b. The transmitting UE 1320a, which receives the sidelink scheduling grant, transmits an SCI for scheduling sidelink data according to the sidelink scheduling grant to the receiving UE 1320b via the PSCCH, and transmits the sidelink data via the PSSCH. The receiving UE 1320b, which receives the SCI, may receive the sidelink data transmitted via the PSSCH. The SCI may include at least one of the following: resource allocation information for sidelink data transmission, MCS information applied to the sidelink data, source ID information, unicast destination ID information, power control information for controlling sidelink power, timing advance information, DMRS configuration information for sidelink transmission, information related to packet repetition transmission, such as information about the number of packet repetition transmissions, information related to resource allocation when repetitively transmitting a packet, RV, or HARQ process ID. The SCI may also include feedback information for the sidelink data, i.e., information indicating the resources through which ACK / NACK information is transmitted.

[0201] In operation 1309, the receiving UE 1320b sends a PSFCH. The receiving UE 1320b sends ACK / NACK information indicating whether the decoding of the sidelink data is successful or failed to the sending UE 1320a via the PSFCH. The transmission of sidelink feedback information can be applied to unicast transmission or multicast transmission, but the present disclosure does not exclude broadcast transmission. When the sidelink transmission corresponds to multicast transmission, the corresponding UE receiving the multicast data can send feedback information through different PSFCH resources. Alternatively, the corresponding UE receiving the multicast data can send feedback information through the same PSFCH resource. In this case, only NACK information can be fed back. That is, in the case of ACK, the UE receiving the data may not send feedback. At this time, the PSFCH resources can include not only resources distinguished in the time domain or / and frequency domain, but also resources distinguished using codes, such as scrambling codes or orthogonal cover codes, and resources distinguished using different sequences and cyclic shifts applied to the sequences.

[0202] In operation 1311, transmitting UE 1320a transmits a PUCCH or PUSCH to BS 1310. Transmitting UE 1320a reports HARQ feedback to BS 1310 via the PUCCH or PUSCH. BS 1310 may configure, through system information or RRC, reporting of HARQ feedback received by transmitting UE 1320a from receiving UE 1320b. In this case, transmitting UE 1320a may transmit sidelink HARQ feedback received from receiving UE 1320b to BS 1320 via the PUCCH or PUSCH. In addition, BS 1310 may configure whether transmitting UE 1320a multiplexes and transmits the sidelink HARQ feedback information received from receiving UE 1320b with the UCI of the related domain Uu.

[0203] When BS 1310 is configured to transmit sidelink HARQ feedback to BS 1310 via a PUCCH and does not multiplex the sidelink HARQ feedback information and UCI, transmitting UE 1320a cannot multiplex the sidelink HARQ feedback information and UU UCI and transmit them on a single PUCCH. In this case, BS 1310 can configure a PUCCH for transmitting sidelink HARQ feedback information independently of the PUCCH for transmitting UCI. In other words, the PUCCH for transmitting sidelink HARQ feedback information can exist independently, and any UCI can be transmitted in the corresponding PUCCH.

[0204] In contrast, when BS 1310 configures the transmission of sidelink HARQ feedback to BS 1310 via the PUCCH and multiplexing of the sidelink HARQ feedback information and UCI, transmitting UE 1320a may multiplex the sidelink HARQ feedback information and UCI to transmit them on a single PUCCH. Assuming that the sidelink HARQ feedback information consists of N1 bits and the UCI consists of N2 bits, the multiplexing order may follow N2+N1. That is, the sidelink HARQ feedback information may be multiplexed after the UCI. When the code rate of the sum of the sidelink HARQ feedback bits and the UCI bits multiplexed and transmitted via the corresponding PUCCH is greater than the code rate configured by BS 1310, transmitting UE 1320a may not abandon the transmission of the sidelink HARQ feedback information. In other words, transmitting UE 1320a may discard the sidelink HARQ feedback information. In another example, the multiplexing order may follow N1+N2. That is, the sidelink HARQ feedback information may be multiplexed after the UCI. At this time, when the code rate of N1+N2 is greater than the code rate configured by BS 1310, transmitting UE 1320a may abandon the transmission of UCI. In other words, transmitting UE 1320a may discard the UCI.

[0205] In another example, whether transmitting UE 1320a forgoes sending sidelink HARQ feedback information or forgoes sending UCI can be determined based on priority. In this case, the priority can follow a preset rule based on the type of UCI. For example, a rule can be defined such that HARQ feedback information for downlink data has a higher priority than sidelink HARQ feedback information. A rule can also be defined such that feedback information for downlink CSI has a lower priority than sidelink HARQ feedback information. In this case, transmitting UE 1320a can forgo sending the information with the lower priority.

[0206] In another example of priority, whether to discard sidelink HARQ feedback information or discard UCI can be determined based on a priority index configured by a higher layer. For example, the transmitting UE 1320a can receive a priority index for sidelink data information corresponding to the sidelink HARQ feedback information from a higher layer, and a priority index for downlink UCI from a higher layer. The transmitting UE 1320a can compare the priority indexes and discard the information with the lower priority.

[0207] Figure 13 Assume that both the transmitting UE 1320a and the receiving UE 1320b are within the coverage of the BS 1310. Figure 13 Although not shown, in a scenario where the transmitting UE 1320a exists within the coverage of the BS 1310 and the receiving UE 1320b exists outside the coverage of the BS 1310, the receiving UE 1320b may receive configuration of information for side link communication in advance to use the configuration.

[0208] "Information for sidelink communication" may be understood as information about the reference Figure 12 In one example, the pre-received configuration may be interpreted as using a value embedded in the UE when the UE is released. In another example, when the transmitting UE 1320a or the receiving UE 1320b accesses the BS 1310 and pre-acquires information about the sidelink communication through RRC settings or has already acquired information about the sidelink communication through system information of the BS 1310, the pre-received configuration may refer to the most recently acquired information.

[0209] Figure 13 Although sidelink unicast communication for only one sidelink receiving UE is shown, it can be applied to sidelink multicast communication and sidelink broadcast communication for multiple receiving UEs. However, in the case of sidelink broadcast communication, the process of the receiving UE sending the PSFCH to the transmitting UE or the process of the transmitting UE sending the PUCCH or PUSCH to the base station can be omitted.

[0210] As described above, sidelink communication can be performed between two or more UEs. A UE transmitting sidelink data uses resources within a resource pool for the sidelink. According to various embodiments, the BS can configure at least one sidelink BWP, and can configure a single sidelink resource pool or multiple sidelink resource pools within the configured sidelink BWP. For example, to support higher reliability and higher data transmission rates, multiple resource pools for sidelink communication can be configured. When multiple sidelink resource pools are configured within a BWP, the sidelink transmitting UE can perform an operation for selecting a sidelink resource pool. This is because it is not preferable for a sidelink transmitting UE to simultaneously perform two or more sidelink transmissions on a frequency or carrier that allows sidelink communication.

[0211] As described above, the configuration information for the sidelink resource pool may include information about a set of time slots in which sidelink transmission is possible on the time axis. When a sidelink-transmitting UE needs to transmit in two sidelink resource pools (e.g., resource pool A and resource pool B), at least one of the sidelink time slots included in resource pool A and the sidelink time slots included in resource pool B may overlap at the same time point. In this case, the UE should distribute the transmit power to the sidelink signal transmission in resource pool A and the sidelink signal transmission in resource pool B. Due to the distribution of transmit power, the coverage of the sidelink can be reduced compared to a single sidelink transmission.

[0212] In order to solve the problem of reduced coverage, when two or more side link resource pools are configured, the transmitting UE can select the resource pool including the resources that are first located after the corresponding time point on the time axis. When the side link resources of the selected resource pool (e.g., resource pool A) overlap with the side link resources of another resource pool (e.g., resource pool B), the UE can give up sending side link control information and data information or feedback information sent in resource pool B. Alternatively, the UE can give up sending the side link in the resource pool with a lower priority based on the priority provided by the higher layer. When the priority is the same, the UE can randomly select to send side link control information and data information or feedback information. In another example, when the UE that starts side link transmission in resource pool A has side link control information and data information or feedback information to be sent in resource pool B, the UE can give priority to side link transmission in the resource pool that starts sending. However, the above scheme is not preferred because the configuration of the side link resources according to different resource pools can cause the frequency of side link transmission to decrease. Therefore, sidelink transmissions may be performed simultaneously through different carriers (carrier aggregation (CA)), but two or more simultaneous sidelink transmissions may not be preferred.

[0213] Therefore, when the BS configures two or more resource pools in one carrier, the UE may select one resource pool according to various embodiments. When two or more resource pools are configured, the UE attempting to send sidelink data may do the following: Figure 14 Proceed as shown.

[0214] Figure 14 FIG14 is a flowchart 1400 of a UE transmitting a sidelink signal in a wireless communication system according to an embodiment of the present disclosure.

[0215] Figure 14 A method of operating UE 120 or UE 130 is shown.

[0216] refer to Figure 14 In operation 1401, the UE obtains configuration information of multiple resource pools. The configuration information of the resource pools can be obtained through system information. For example, the configuration information of the resource pools can include at least one item listed in Table 2. Multiple resource pools can be included in one BWP.

[0217] In operation 1403, the UE transmits a sidelink signal through one of a plurality of resource pools. The UE may select one of the resource pools included in the same BWP and transmit the sidelink signal through resources in the selected resource pool. According to various embodiments, the UE may select a resource pool based on at least one of the following: characteristics of the sidelink data or service (quality of service (QoS) requirements, whether HARQ feedback is required, or communication type), characteristics of the resource pool (e.g., index, resource distribution, or congestion level), channel quality (e.g., channel quality between the BS and the UE or channel quality between UEs), or UE status.

[0218] Figure 15 FIG15 is a flowchart 1500 of a UE performing sidelink communication in a wireless communication system according to an embodiment of the present disclosure.

[0219] Figure 15 A method of operating UE 120 or UE 130 is shown.

[0220] refer to Figure 15In operation 1501, the UE acquires synchronization and system information. For example, when the sidelink UE is within the coverage of the BS, the UE can perform synchronization with the BS through a downlink synchronization signal and a sidelink-specific SIB, and acquire sidelink system information. In another example, even if the UE is within the coverage of the BS, the UE can use a global navigation satellite system (GNSS) or a global positioning system (GPS) instead of the BS to perform synchronization. Whether the UE within the coverage of the BS performs synchronization with the BS or with the GNSS / GPS can be indicated by system information or RRC, or can be pre-configured in the UE by the BS. The sidelink UE performing synchronization can obtain sidelink system information from the BS through a sidelink-specific SIB. In another example, the UE can perform synchronization using a synchronization signal sent by another sidelink UE. In this case, the acquisition of synchronization and system information in this operation can be understood as being acquired through a synchronization signal and a sidelink broadcast channel (physical sidelink broadcast channel (PSBCH)) sent by another sidelink UE.

[0221] In operation 1503, the UE obtains resource pool configuration information. The obtained sidelink system information may include at least one sidelink BWP information, and the sidelink BWP information may include configuration information of at least one sidelink resource pool. The configuration information of the sidelink resource pool may include at least one of the parameters shown in Table 2, and the timeline resource of the sidelink resource pool may be based on the reference Figure 12 or Figure 15 The described procedures are assigned to sidelink UEs.

[0222] In operation 1505, the UE identifies whether multiple resource pools are configured. The UE that obtains system information from the BS can obtain the BWP configuration information included in the system information and the resource pool information included in the BWP configuration information. At this time, the sidelink UE can determine whether multiple resource pools are configured.

[0223] When multiple resource pools are not configured, that is, when a single resource pool is configured, the UE determines whether to perform sidelink transmission or sidelink reception in operation 1507. When a single resource pool is configured and the UE should perform sidelink transmission, the UE transmits a sidelink signal through the resources in the resource pool in operation 1509. In other words, the UE can select a sidelink transmission resource for transmitting sidelink control information and data in the configured single resource pool, and transmit the sidelink control information and data through the selected resource. At this time, the sidelink transmission resource can be selected by various methods such as sensing and random selection. The sidelink UE that selects the transmission resource can transmit the sidelink control information and data information through the selected resource. When a single resource pool is configured and the UE should perform sidelink reception, the UE can receive the sidelink control information and data information in the configured single resource pool in operation 1511.

[0224] When multiple resource pools are not configured, the UE determines whether to perform sidelink transmission or sidelink reception in operation 1513. When multiple resource pools are configured and the UE should perform sidelink transmission, the UE selects one of the multiple resource pools in operation 1515. Subsequently, in operation 1517, the UE transmits a sidelink signal through the resources in the selected resource pool. In other words, the UE can select a sidelink transmission resource for transmitting sidelink control information and data in a single configured resource pool, and transmit the sidelink control information and data through the selected resource. At this time, the sidelink transmission resource can be selected by various methods such as sensing and random selection. The sidelink UE that selects the transmission resource can transmit sidelink control information and data information through the selected resource. When multiple resource pools are configured and the UE should perform sidelink reception, the UE can receive sidelink control information and data information in the configured multiple resource pools in operation 1519.

[0225] At the same time, the sidelink transmitting UE and the receiving UE may be located outside the coverage of the BS, or some sidelink transmitting and receiving UEs may be located within the coverage of the BS (within coverage), while the remaining UEs may be located outside the coverage of the BS (out of coverage). In this case, the sidelink transmitting and receiving UEs may perform sidelink transmission and reception within a pre-configured sidelink BWP, and multiple sidelink resource pools may be configured within the sidelink BWP.

[0226] As reference Figure 14 or Figure 15 As described, when multiple resource pools are configured, the UE may transmit a sidelink signal after selecting one resource pool. Hereinafter, the present disclosure describes various embodiments of matters considered in resource pool selection.

[0227] Method 1) Resource pool selection based on communication type

[0228] The demand may vary according to the type of sidelink communication, such as unicast, multicast, and broadcast. For example, unicast communication can operate sidelink HARQ and sidelink channel state information (CSI) feedback, and therefore may be suitable for performing highly reliable sidelink communication. However, in the case of unicast communication, the delay time (or latency) of the sidelink communication may increase due to the feedback operation. On the other hand, broadcast communication cannot support sidelink HARQ and sidelink CSI feedback, and therefore may achieve relatively lower reliability compared to unicast communication. However, in the case of broadcast communication, there is no feedback operation, and compared with unicast communication operation feedback, the delay time of the sidelink communication can be reduced. Therefore, the sidelink resource pool can be independently configured according to the type of sidelink communication, such as unicast, multicast, and broadcast. That is, the resource pool used by the UE performing sidelink unicast communication, the resource pool used by the UE performing sidelink multicast communication, and the resource pool used by the UE performing sidelink broadcast communication can be configured separately. In this case, the UE can select the corresponding resource pool according to the type of sidelink communication to be performed. When multiple resource pools support the same type, the UE may randomly select a resource pool, or may select a resource pool through another method described in the present disclosure.

[0229] Method 2) Resource pool selection based on whether feedback channel is needed

[0230] When configuring resource pools based on communication types, inefficient resource usage may occur depending on the number of UEs performing sidelink unicast, multicast, and broadcast communications, so it may not be preferable to configure resource pools for each communication type. Therefore, a method of sharing resource pools that is independent of the sidelink communication type can be used. That is, according to one embodiment, UEs performing unicast, multicast, and broadcast communications can share and use a resource pool. When UEs performing unicast, multicast, and broadcast communications share a resource pool, some UEs may require a PSFCH for HARQ feedback, while the remaining UEs may not require a PSFCH for HARQ feedback. For example, UEs performing unicast, multicast, and broadcast communications may or may not be configured to operate HARQ feedback. UEs performing sidelink broadcast communications cannot operate HARQ feedback. Therefore, depending on the sidelink communication type and whether HARQ feedback is operated, some UEs may require a PSFCH or some UEs may not require a PSFCH.

[0231] Therefore, when the first resource pool includes PSFCH and the second resource pool does not include PSFCH, among the configured multiple resource pools, the UE can select a resource pool according to whether PSFCH is needed (i.e., whether HARQ feedback operation is needed). According to one embodiment, whether PSFCH is needed may depend on the side link communication type, such as unicast, multicast or broadcast. When the side link transmitting UE should perform broadcast communication, unicast communication without HARQ feedback configuration, or multicast communication without HARQ feedback configuration, the UE can select a resource pool without PSFCH resources configuration. On the other hand, when the UE should perform unicast and multicast communication with HARQ feedback configuration, the UE can select a resource pool with PSFCH resources configuration. When multiple resource pools all include PSFCH or do not include PSFCH, the UE can randomly select a resource pool, or can select a resource pool by another method described in the present disclosure.

[0232] Depending on the method of configuring the sidelink resource pool and the method of configuring the PSFCH resources within the sidelink resource pool, resource efficiency may be different and UE operation may be favorable or unfavorable. Figure 16 and Figure 17 Describes the structure of the time slots in the resource pool that include the PSFCH.

[0233] Method 3) Resource pool selection based on resource location

[0234] Multiple configured resource pools may occupy different resources (e.g., RBs or RBGs) on the frequency axis or different resources (e.g., time slots) on the time axis. When multiple resource pools occupy different resources on the time axis, the UE may select a resource pool that includes resources that are located first on the time axis after the time point when the sidelink data is generated. Thus, the UE can minimize the transmission delay of the sidelink data. When the resources located first on the time axis in the resource pools are the same, the UE may randomly select a resource pool, or may select a resource pool using another method described in the present disclosure.

[0235] Method 4) Resource pool selection based on downlink reference signal received power (RSRP)

[0236] When a BS operates time / frequency resources for cellular communication and time / frequency resources for sidelink communication in the same carrier—in other words, when cellular communication and sidelink communication share resources—sidelink transmissions can interfere with the uplink signal received by the BS. For example, when sidelink transmission and uplink transmission are performed in different frequency blocks in the same time slot, even when using orthogonal resources on the frequency axis, sidelink transmissions can cause in-band transmission of the uplink signal received by the BS. This is because when a sidelink transmitting UE located near the BS performs sidelink transmission at high transmit power, sidelink signals that exceed the dynamic range of the BS's receiving side act as interference and distort the signal received via the uplink. This problem can be addressed by reducing the sidelink transmit power of sidelink transmitting UEs adjacent to the BS. However, when the sidelink transmit power is reduced, the sidelink signal may not reach the sidelink receiving UE. To address this issue, the UE can select a resource pool based on the downlink RSRP. In other words, sidelink UEs with downlink RSRP values ​​similar to that of the BS have a high probability of being at a similar distance from the BS. When such UEs use the same resource pool, interference to sidelink transmission on the receiving side of the BS can be reduced, and the possibility of the sidelink signal reaching the receiving UE can be relatively increased.

[0237] A UE that should perform sidelink transmission (sidelink transmitting UE) can measure downlink RSRP using a downlink reference signal (DL RS) transmitted by the BS through a downlink. In this case, the downlink reference signal may be a secondary synchronization signal (SSS) and / or DMRS of the physical broadcast channel (PBCH) or a downlink channel state information reference signal (CSI-RS), and the reference signal used to measure downlink RSRP may be indicated by the BS.

[0238] In order to select a resource pool based on downlink RSRP, information indicating an upper threshold and a lower threshold of downlink RSRP may be sent through system information. For example, when two resource pools are configured (e.g., resource pool A and resource pool B), the information indicating the threshold may include a first upper threshold and a first lower threshold that can be applied to the downlink RSRP of resource pool A, and a second upper threshold and a second lower threshold that can be applied to the downlink RSRP of resource pool B. When the information indicating the threshold is included in the system information, the sidelink transmitting UE can measure the downlink RSRP value through the downlink reference signal and select a resource pool that meets the indicated conditions from among multiple resource pools.

[0239] Method 5) Resource pool selection based on sidelink RSRP

[0240] A sidelink receiving UE can receive sidelink control information and data information from a transmitting UE. At this time, another adjacent transmitting UE can send sidelink control information and data information to another receiving UE. The transmitted signal from another transmitting UE can act as interference in the received signal of the receiving UE in the same way as the sidelink signal in the above method 4) causes interference in the BS. This interference problem may occur even when the time / frequency resources used for cellular communication and the time / frequency resources used for sidelink communication are not operated in the same carrier. Therefore, resource pool selection based on sidelink RSRP may be required.

[0241] The sidelink transmitting UE can measure the sidelink RSRP by a reference signal (sidelink reference signal (SL RS)) transmitted by another sidelink UE through the sidelink. At this time, the sidelink reference signal can be a sidelink secondary synchronization signal (S-SSS) and / or a DMRS or a sidelink CSI-RS of a physical sidelink broadcast signal (PSBCH), and the reference signal for measuring the sidelink RSRP can be configured by PC-5 RRC, or one of the reference signals can always be used to measure the sidelink RSRP. Before performing unicast communication, the sidelink transmitting UE can perform a PC-5 RRC connection setup with the sidelink receiving UE. In addition, a sidelink transmitting UE that desires to perform groupcast communication can establish a unicast connection with a receiving UE within the group. The sidelink transmitting UE can measure the sidelink RSRP value during the process of establishing the connection, and can select a resource pool by the RSRP value.

[0242] To select a resource pool based on the sidelink RSRP, the base station may transmit, via system information, information indicating an upper and lower threshold for the sidelink RSRP that may be applied to each resource pool. For example, when two resource pools (e.g., resource pool A and resource pool B) are configured, the threshold information may include a first upper and lower threshold for the sidelink RSRP that may be applied to resource pool A, and a second upper and lower threshold for the sidelink RSRP that may be applied to resource pool B. In another example, the information indicating the upper and lower thresholds for the sidelink RSRP may be configured via PC-5 RRC or may be pre-configured in the UE.

[0243] The above methods 4) and 5) can complement each other.

[0244] According to one embodiment, method 4) or 5 may be selectively used based on the link of the threshold value indicated by the information included in the system information. For example, when information about the downlink RSRP threshold value is included in the system information, the sidelink transmitting UE may measure the downlink RSRP value using the downlink reference signal and select a resource pool that meets the condition. In another example, when information about the sidelink RSRP threshold value is included in the system information, the sidelink transmitting UE may measure the sidelink RSRP value using the sidelink reference signal and select a resource pool that meets the condition.

[0245] According to another embodiment, for the operation of selecting a resource pool for a sidelink transmitting UE, the BS may transmit information indicating an upper threshold value of min{downlink RSRP, sidelink RSRP} and a lower threshold value of min{downlink RSRP, sidelink RSRP} that can be applied to each resource pool through system information. For example, when two resource pools are configured (e.g., resource pool A and resource pool B), the information indicating the threshold value may include a first upper threshold value of min{downlink RSRP, sidelink RSRP} and a first lower threshold value of min{downlink RSRP, sidelink RSRP} that can be applied to resource pool A, and a second upper threshold value of min{downlink RSRP, sidelink RSRP} and a second lower threshold value of min{downlink RSRP, sidelink RSRP} that can be applied to resource pool B. In this case, after measuring both the downlink RSRP and the sidelink RSRP, the sidelink transmitting UE may identify the smaller value between the downlink RSRP and the sidelink RSRP, and select a resource pool that meets the conditions.

[0246] In methods 4) and 5), RSRP is used to select a resource pool. RSRP is an example of an index indicating channel quality and can be replaced with another index. For example, one of the signal-to-noise ratio (SNR), signal-to-interference plus noise ratio (SINR), reference signal received quality (RSRQ), and RSSI can be used.

[0247] Method 6) Resource pool selection based on congestion level

[0248] The sidelink transmitting UE can measure the congestion level and select a resource pool with a congestion level, that is, a resource pool with low congestion. The congestion level can be measured by the ratio (=B / A) of the number of resources occupied by another UE (=B) to the number of total resources included in the sidelink resource pool (=A). The sidelink resource can be a unit that can be used for transmission by one sidelink UE and can be defined as K symbols and N resource blocks (1≤k≤14, 1≤N≤Nmax). Nmax can be the maximum number of frequency blocks that can be used by one sidelink UE for sidelink transmission and can be a parameter determined according to the BWP size, the size of the frequency of the resource pool and the capability of the sidelink UE. B can be calculated by the sidelink transmitting UE by comparing the total received signal strength indication (RSSI) of the OFDM symbols included in the sidelink resource pool with a threshold of RSSI configured (or pre-configured) by the BS or through PC-5 RRC. More specifically, assuming that the number of OFDM symbols included in the resource pool is X, the RSSI value of each symbol can be calculated (e.g., a total of X RSSI values), and the average RSSI value can be calculated over the X symbols. The sidelink transmitting UE can compare the measured RSSI value with an RSSI threshold configured or pre-configured by the BS or through PC-5 RRC, and when the measured RSSI value is greater than the configured RSSI threshold, it is determined that the corresponding resource is occupied by another UE. Therefore, the corresponding resource can be included in B. In this example, the RSSI calculation can be performed on all symbols included in the resource pool, but the calculation can also be performed on some symbols included in the resource pool.

[0249] The congestion level can be measured during a specific time interval. For example, A and B can be measured for sidelink resources present in the time interval between time slots [na, n-1] in the configured resource pool. Therefore, the congestion level measured in time slot n can be the congestion level measured for sidelink resources present in the time interval between time slots [na, n-1]. In this case, a can be a fixed value (or a preconfigured value) or can be configured through BS system information or PC-5 RRC.

[0250] There may be two or more resource pools with the same congestion level. That is, there may be two or more resource pools with the lowest congestion level, and the congestion levels in the respective resource pools may be the same. In this case, the UE may randomly select a resource pool, or may select a resource pool using another method described in this disclosure.

[0251] Method 7) Resource pool selection based on resource pool index

[0252] Resource pools may have unique indices. Thus, a sidelink transmitting UE may select a resource pool based on the resource pool index. For example, the UE may select the resource pool with the lowest index or the resource pool with the highest index.

[0253] Method 8) Resource pool selection based on Quality of Service (QoS)

[0254] The sidelink UE can receive QoS parameter configuration from a higher layer of the UE based on the type of sidelink data. For example, a high value can be set for delay (or latency) requirements for specific sidelink data, a high value can be set for reliability requirements for specific sidelink data, or a high value can be set for both delay and reliability requirements for specific sidelink data. The UE can select a resource pool based on meeting the QoS requirements.

[0255] For example, if the sidelink data sets a high value for reliability, the UE can select a resource pool with a relatively low congestion level. If the sidelink data sets a high value for latency, the UE can select sidelink resources with a lower frequency on the time axis, even if the congestion level is relatively high. For example, when two resource pools are configured (e.g., resource pool A and resource pool B), the number of time slots included in a radio frame of resource pool A can be relatively smaller than that of resource pool B. In this case, the sidelink UE can select resource pool B.

[0256] In another example, when the QoS requirement of the sidelink data, control information, or feedback information sent by the sidelink transmitting UE places a higher priority on delay time (latency) than reliability, or when the QoS requirement requires a shorter delay time than general sidelink data information (for example, when general sidelink data should guarantee a delay time of 10ms, but the QoS requirement of the sidelink data requires a delay time of 5ms), the sidelink transmitting UE may select a resource pool that is not configured with PSFCH resources. On the other hand, when the QoS requirement of the sidelink data, control information, or feedback information sent by the sidelink transmitting UE places a higher priority on reliability than delay time, or when the QoS requirement requires a higher reliability than general sidelink data information (for example, when general sidelink data should guarantee a delay time of 10ms, but the QoS requirement of the sidelink data requires a delay time of 5ms), the sidelink transmitting UE may select a resource pool that is not configured with PSFCH resources. -2 reliability, but the QoS requirement of the side link data needs 10 -3 The sidelink transmitting UE can select a resource pool configured with PSFCH resources when reliability is not guaranteed. The reference value of the delay time or reliability can be configured by PC-5 RRC.

[0257] When there are multiple resource pools that meet the QoS requirements, the UE can randomly select a resource pool, or can select a resource pool by another method described in the present disclosure. In a specific example, there may be multiple resource pools that meet the QoS requirements (for example, M resource pools), M1 resource pools among the M resource pools may have PSFCH resources, and M2 resource pools may not have PSFCH resources (M=M1+M2). In this case, the UE can select a resource pool by applying one of the methods described in the present disclosure, or can randomly select a resource pool.

[0258] A method defined by combining two or more of methods 1) to 8) may be used. For example, two or more methods may be combined sequentially. In this case, if a resource pool is not selected by one method, a resource pool may be selected by another method. In another example, two or more methods may be combined with predefined weights, and based on the determination results of the multiple methods, a resource pool may be selected by the sum of the weights.

[0259] Figure 16 An example of the structure of a side link resource pool in a wireless communication system according to an embodiment of the present disclosure is shown.

[0260] refer to Figure 16 , time slots with indices 1, 2, 5, 7, 8, and 9 are a group of side link time slots configured as a side link resource pool. Time slots with indices 0, 3, 4, and 6 are time slots for uplink communication or downlink communication. At this time, time slots with indices 1 and 8 are time slots 1610 including PSFCH resources, and time slots with indices 2, 5, 7, and 9 are time slots 1620 not including PSFCH resources. Figure 16 In the example of , time slots with indices 1, 2, 5, 7, 8, and 9 may be included in the same side link resource pool, or may be included in different side link resource pools. When the side link time slots are included in the same resource pool, Figure 16 The case where the PSFCH timeline resources start from time slot index 1 and exist according to a cycle of 4 time slots is shown. When the sidelink time slots are included in different sidelink resource pools, a group of time slots that do not include PSFCH resources (for example, time slots with indices 2, 5, 7, and 9) can configure one sidelink resource pool and a group of time slots that include PSFCH resources (for example, time slots with indices 1 and 8) can configure another sidelink resource pool.

[0261] exist Figure 16In

[16] , a time slot includes K symbols and M resource blocks. K, M, and the number of RBs in an RBG can be included in the resource pool configuration information. Therefore, in time slot 1610 and time slot 1620, K and M can be the same or different depending on the resource pool configuration. For example, when time slot 1610 and time slot 1620 belong to the same resource pool, K and M can be the same. However, when time slot 1610 and time slot 1620 belong to different resource pools, K and M can be different.

[0262] In time slots 1610 and 1620, at least one symbol at the end can be used as a gapped access point (GAP), which is a guard symbol used to switch to reception after sidelink transmission, or to switch to transmission after sidelink reception. For example, when one symbol is used as a gapped access point (GAP), K-1 symbols can be used to transmit and receive the PSCCH, PSSCH, and PSFCH. Unlike time slot 1620, time slot 1610 can include additional guard symbols. In this case, the additional guard symbols can be used to switch to PSFCH transmission after PSCCH and PSSCH reception, or to switch to PSFCH reception after PSCCH and PSSCH transmission.

[0263] Figure 16 Timeslot 1620 does not include the PSFCH, and therefore a sidelink UE that desires to transmit or receive the PSFCH cannot use Figure 16 16. Therefore, a UE that desires to increase the reception reliability of the sidelink signal through HARQ feedback may not use the structure of time slot 1620. At the same time, in the case of time slot 1610, PSFCH resources exist in at least some of the M resource blocks included in the time slot, and PSFCH resources do not exist in the remaining resource blocks. Therefore, a sidelink UE that desires to send or receive PSFCH (for example, a UE that desires to perform unicast communication with HARQ feedback operation configured or a UE that configures HARQ feedback operation) can send or receive PSFCH in the corresponding PSFCH resource. In addition, a UE that does not need PSFCH (for example, a UE that desires to perform unicast communication without HARQ feedback operation or a UE that does not configure HARQ feedback operation) can send PSCCH / PSSCH in symbols other than RBGs and GAPs that do not include PSFCH resources (for example, K-1 symbols when it is assumed that one symbol is a GAP). Alternatively, a UE that does not require PSFCH may transmit PSCCH / PSSCH in symbols other than the RBG and GAP+PSFCH+GAP including PSFCH resources (e.g., K-3 symbols when assuming one symbol GAP, one symbol PSFCH, and another symbol GAP). Figure 16In the example shown in FIG5 , a UE that transmits and receives only PSCCH / PSSCH but not PSFCH can transmit or receive PSCCH / PSSCH using the RBG where PSFCH exists and (K-3) symbols, or can transmit or receive PSCCH / PSSCH using the remaining RBGs where PSFCH does not exist and (K-1) symbols. Therefore, since UEs that do not require PSFCH resources and UEs that require PSFCH resources coexist in the same resource pool, the inefficiency of resource usage can be improved compared to a case where different resource pools are used for each type of sidelink communication.

[0264] Figure 16 The use of time slot 1610 may affect automatic gain control (AGC) configuration as follows. "AGC configuration" refers to the operation of determining and applying gain values ​​for AGC operation.

[0265] A UE that first receives the PSCCH / PSSCH in slot #1 or slot #9 can use the first symbol of the corresponding slot for AGC configuration to receive the PSCCH / PSSCH. After performing AGC configuration, the UE can then use this configuration to receive the remaining symbols in the slot. Meanwhile, a UE that first receives the PSFCH in slot #1 or slot #8 can use the first PSFCH symbol of the corresponding slot for AGC configuration to receive the PSFCH. After performing AGC configuration, the UE can then use this configuration to receive the remaining PSFCH symbols.

[0266] AGC configuration can be performed based on the energy received across all bandwidths of the resource pool to be received, and when a gain value for AGC operation is configured once for the first symbol, the gain value can be applied equally to the remaining symbols of the corresponding time slot. Therefore, a UE receiving both PSCCH / PSSCH and PSFCH can use the first symbol of time slot 1610 and the first symbol of PSFCH for AGC configuration. However, in the case of time slot 1610, PSFCH is received in some RBGs of the resource pool and PSCCH / PSSCH is received in the remaining RBGs, and therefore the AGC configuration for the first symbol of PSFCH may be erroneous. The error may distort the PSFCH received signal, which may degrade the performance of the sidelink.

[0267] Figure 17 Another example of the structure of a side link resource pool in a wireless communication system according to an embodiment of the present disclosure is shown.

[0268] refer to Figure 17, time slots of indices 1, 2, 5, 7, 8, and 9 are a group of side link time slots configured as a side link resource pool. Time slots of indices 0, 3, 4, and 6 are time slots for uplink communication or downlink communication. At this time, time slots of indices 1 and 8 are time slots 1710 including PSFCH resources, and time slots of indices 2, 5, 7, and 9 are time slots 1720 not including PSFCH resources. Figure 17 , in time slot 1710 including PSFCH resources, the PSFCH resources occupy all bandwidth (eg, M RBs) of the resource pool.

[0269] exist Figure 16 In the case of , a UE that transmits and receives only PSCCH / PSSCH but not PSFCH can transmit or receive PSCCH / PSSCH through RBG×(K-3) symbols where PSFCH resources exist, or can transmit or receive PSCCH / PSSCH through the remaining RBG×(K-1) symbols where PSFCH does not exist. Therefore, compared with the case of using different resource pools for each type of side link communication, Figure 16 The structure can improve the inefficiency of resource usage. However, when using Figure 17 , a UE that transmits or receives PSCCH / PSSCH but not PSFCH can always use only a maximum of (K-3) symbols. Figure 16 Compared with the use of the structure, Figure 17 The use of a structure may be inefficient in terms of resource usage. However, as mentioned above, due to Figure 16 The AGC configuration in the , there is a problem of receiving performance degradation, but when using Figure 17 Therefore, depending on whether HARQ operation is configured and the method of allocating unicast, multicast and broadcast communication schemes to the side link resource pool, Figure 17 The time slot 1710 may have a trade-off relationship between resource usage efficiency and AGC configuration.

[0270] As a way to best satisfy the trade-off, consider the following resource pool configuration methods. Figure 17 In the example of the time slot cycle, there is a case where the time slot of the PSFCH resource corresponds to the time slot cycle 4 (i.e., N=4). In another example of the time slot cycle, N=1 (PSFCH resource exists in every time slot) and N=2 (PSFCH resource exists in every two time slots). Therefore, in Figure 17In the case of a time slot structure and N=4, UEs that do not need to send and receive PSFCH (for example, UEs that expect to perform unicast communication without HARQ feedback operation or multicast or broadcast communication without HARQ feedback operation) can use time slots 1720 with indices 2, 5, 7, and 9, in which there are no PSFCH resources to send or receive PSCCH / PSSCH, thereby maximizing resource utilization efficiency. In addition, UEs that need to send and receive PSFCH (for example, UEs that expect to perform unicast communication with HARQ feedback operation or multicast communication with HARQ feedback operation) can use time slots 1710 with indices 1 and 8, in which there are PSFCH resources to send and receive PSCCH / PSSCH and send and receive PSFCH, thereby solving the problem of AGC configuration of PSFCH. This method can be extended to Figure 17 The structure of time slot 1710 and the case where N=2.

[0271] At the same time, the example can be applied to the case of N=1, but the advantage is that the transmitting / receiving UE that does not need to transmit and receive PSFCH (for example, a UE that expects to perform unicast communication without configuring HARQ feedback operation or multicast or broadcast communication without configuring HARQ feedback operation) uses resources inefficiently. Therefore, in order to solve the problem of low resource utilization efficiency, the resource pool including PSFCH and the resource pool not including PSFCH can be independently configured. For example, in Figure 17 , time slots with indices 1 and 8 may correspond to resource pool A, and time slots with indices 2, 5, 7, and 9 may correspond to resource pool B. UEs that need to transmit and receive the PSFCH (e.g., UEs that desire to perform unicast communication with a HARQ feedback operation configured or multicast communication with a HARQ feedback operation configured) may use resource pool A, and UEs that do not need to transmit and receive the PSFCH (e.g., UEs that desire to perform unicast communication without a HARQ feedback operation configured or multicast or broadcast communication without a HARQ feedback operation configured) may use resource pool B.

[0272] Figure 18 An example of a sidelink hybrid automatic repeat request (HARQ) operation method in a wireless communication system according to an embodiment of the present disclosure is shown.

[0273] Figure 18 Can include Figures 12 to 13 embodiment, and Figures 12 to 13 Figure 1 shows a unicast communication with one sending UE and one receiving UE. Figures 12 to 13 different, Figure 18 An example of multicast communication in which the number of receiving UEs is two or more is shown. Figure 181820a, and receiving UEs 1820b-1, 1820b-N according to a sidelink communication procedure of multicast. Receiving UEs 1820b-i may be used as an example to describe the operation of a receiving UE or to describe a receiving UE.

[0274] refer to Figure 18 , in operation 1801, BS 1810 configures system parameters. Figure 18 The following scenario is shown: the transmitting UE 1820a and the receiving UEs 1820b-1 to 1820b-N are within the coverage of the BS 1810, and therefore the transmitting UE 1820a and the receiving UEs 1820b-1 to 1820b-N can receive system information for sidelink communication from the BS 1810. Parameters for the sidelink communication can be configured in the UE receiving the system information, and the system information can include resource pool configuration information. The resource pool configuration information can include at least one of the information shown in Table 2. When the transmitting UE 1820a and the receiving UE 1820b-i are outside the coverage of the BS 1810 ( Figure 6A In an out-of-coverage scenario), transmitting UE 1820a and receiving UE 1820b-i may receive configuration parameters for sidelink communication in advance, or may receive the configuration via a sidelink master information block (SL-MIB) transmitted via a sidelink synchronization channel. The parameters may include resource pool configuration information, and the resource pool configuration information may include at least one of the information shown in Table 2.

[0275] In operation 1803, the sending UE 1820a and the receiving UE 1820b-i establish a link. Before the multicast communication, all the sending UEs and receiving UEs in the same group can refer to Figure 8 The unicast link establishment process described above is used to perform the PC-5 RRC connection setup. In the described scenario, the unicast link establishment process may include Figure 18 However, with Figure 18 Differently, there may be a scenario where multicast communication is performed without PC-5 RRC connection setup. In this scenario, Figure 18 The unicast link establishment process (operation 1803) may be omitted. Figure 18 The unicast link establishment process is shown as being performed after receiving the system parameter configuration information from BS 1810. However, the system parameter configuration information may be received after the unicast link establishment process is performed. If BS 1810 is not present, the sidelink communication parameters may be configured through the SL-MIB after the unicast link establishment process is performed.

[0276] When Figure 18 Use Figure 12In the resource allocation method of Mode 1 shown in FIG. 1 , BS 1810 may transmit sidelink scheduling information to multicast transmitting UE 1820a via a downlink control channel (Physical Downlink Control Channel (PDCCH)) in operation 1805. In operation 1807, transmitting UE 1820a, which receives the sidelink scheduling information, may transmit sidelink control information and data information to receiving UEs 1820b-1 to 1820b-N via PSCCH and PSSCH based on the scheduling information from BS 1810. In this case, sidelink control information (SCI) may be transmitted separately through two operations. The SCI transmitted via PSCCH may be referred to as the first SCI, and the SCI transmitted via PSSCH may be referred to as the second SCI. The first SCI and the second SCI may be transmitted via the same sidelink timeslot or different sidelink timeslots. The first SCI and the second SCI may include different sidelink control information. For example, both a destination identifier (e.g., a destination L2 ID) and a source identifier (e.g., a transmitter L2 ID) may be inserted into the first SCI and transmitted. Alternatively, the destination identifier (e.g., destination L2 ID) may be transmitted via the first SCI, and the source identifier (e.g., transmitter L2 ID) may be inserted into and transmitted in the second SCI. Furthermore, 1-bit information indicating whether the HARQ operation is activated or deactivated may be included in the first SCI or the second SCI. More specifically, even if PSFCH resource configuration information for the HARQ operation (e.g., PSFCH period) is included in the resource pool configuration information, when information indicating deactivation of the HARQ operation is included in the first SCI or the second SCI, the transmitting UE 1820a may deactivate the HARQ operation. The reason for this is described below.

[0277] In the case of broadcast communication, sidelink control information and data information are sent to multiple unspecified UEs, and therefore it may be difficult to operate HARQ in broadcast communication. In the case of unicast and multicast communication, HARQ operation may or may not be configured according to the QoS of the sidelink data. For example, specific sidelink data has high requirements for reception reliability, and therefore HARQ operation can be configured. However, specific sidelink data has low requirements for reception reliability, and therefore HARQ operation cannot be configured. In another example, specific sidelink data has high requirements for the delay time of sidelink communication (i.e., short delay time), and therefore HARQ operation may not be configured. However, specific sidelink data has low requirements for delay time (i.e., long delay time is not a problem), and therefore HARQ operation can be configured. As described above, HARQ operation can be configured or released according to the QoS of the sidelink data sent by the transmitting UE 1820a. Since whether to configure HARQ operation can vary according to QoS, the configuration can be performed by the V2X layer that receives QoS from the application layer or the application that manages QoS.

[0278] However, in this case, HARQ operation of receiving UE 1820-i may not be possible. More specifically, HARQ operation should be performed by the PHY / MAC layer. However, if HARQ operation is managed by the V2X layer or the application layer, the PHY / MAC layer of receiving UE 1820b-i cannot perform HARQ operation. That is, the PHY / MAC layer of receiving UE 1820b-i should identify whether HARQ is operated before sending the corresponding packet to the V2X layer or the application layer of the receiving UE, and the receiving UE 1820b-i can perform HARQ combined with the PHY layer on this basis. Therefore, for the HARQ operation of the PHY / MAC layer, the transmitting UE 1820a can include a 1-bit indicator indicating whether HARQ is operated in the first SCI or the second SCI.

[0279] At the same time, if Figure 13 As shown, it can be Figure 18 The resource allocation method of mode 2 is used. In this case, the Figure 18 The PDCCH transmission and reception process in (operation 1805).

[0280] In operation 1809, receiving UEs 1820b-1 to 1820b-N receiving the PSCCH and PSSCH from transmitting UE 1820a may determine whether the destination L2 ID included in the SCI (i.e., the first SCI) of the PSCCH indicates the receiving UE, and when the destination L2 ID indicates the receiving UE, decode the PSSCH using the time and / or frequency resource allocation information of the PSSCH included in other SCI (i.e., the second SCI) transmitted through the PSSCH (the time and / or frequency resource allocation information of the PSSCH is included in the second SCI). In another example, when the destination ID included in the first SCI indicates the receiving UE, receiving UE 1820b-i may decode the PSSCH using the time and / or frequency resource allocation information of the PSSCH included in the first SCI (the time and / or frequency resource allocation information of the PSSCH is included in the first SCI).

[0281] After decoding the PSSCH, the receiving UE 1820b-i may ultimately determine whether to transmit the sidelink data to the receiving UE itself using the destination L2 ID included in the MAC Control Element (MAC-CE) transmitted via the PSSCH. That is, the destination L2 ID may consist of N bits, N1 bits may be transmitted via the first SCI, and N2 bits may be transmitted via the MAC-CE (N=N1+N2). If the destination L2 ID included in the received first SCI does not indicate the receiving UE, the receiving UE 1820b-i may not decode the second SCI and the PSSCH indicated by the corresponding SCI.

[0282] When the first SCI of the PSCCH transmitted from transmitting UE 1820a indicates the destination L2 ID of the receiving UE, receiving UE 1820b-i may decode the PSSCH. At this time, receiving UE 1820b-i may send each of HARQ-ACK and HARQ-NACK to transmitting UE 1820a or send only HARQ-NACK to transmitting UE 1820a, depending on the HARQ feedback method and whether the decoding of the PSSCH is successful (indicated by the received first SCI or second SCI). For example, when transmitting UE 1820a indicates the HARQ feedback method of sending each of HARQ-ACK and HARQ-NACK to transmitting UE 1820a in the first SCI or the second SCI, receiving UE 1820b-i may send HARQ-ACK to transmitting UE 1820a if the PSSCH decoding is successful, and send HARQ-NACK to transmitting UE 1820a if the PSSCH decoding fails. On the other hand, when the transmitting UE 1820a indicates the HARQ feedback method of sending only HARQ-NACK in the first SCI or the second SCI, the receiving UE 1820b-i may send HARQ-NACK to the transmitting UE 1820a only when PSCCH decoding fails. That is, when PSSCH decoding succeeds, the receiving UE 1820b-i may not send HARQ-ACK to the transmitting UE 1820a.

[0283] When the transmitting UE 1820a instructs the receiving UE 1820b-i to send each of the HARQ-ACK and HARQ-NACK, at least one piece of HARQ-NACK information may be included in the HARQ feedback information received by the transmitting UE 1820a from the multiple receiving UEs. In this case, the transmitting UE 1820a that receives the HARQ feedback information may retransmit the PSSCH. The PSSCH may be retransmitted to the receiving UE that sent the HARQ-NACK via unicast communication. Alternatively, the PSSCH may be retransmitted via multicast communication. That is, all receiving UEs in the group communication may receive the retransmitted PSSCH. At this time, the UE that sends the HARQ-ACK in response to the transmission of the PSSCH may ignore the retransmission of the PSSCH (i.e., may not perform decoding).

[0284] When all HARQ feedback information received from all receiving UEs 1820b-i to 1820b-N in the group is ACK, transmitting UE 1820a receiving the HARQ feedback information may not retransmit the PSSCH. In other words, transmitting UE 1820a does not retransmit already transmitted data and transmits a new PSSCH when new sidelink data to be transmitted is generated. When no new sidelink data to be transmitted is generated, transmitting UE 1820a may stop PSSCH transmission.

[0285] In operation 1811, transmitting UE 1820a may transmit sidelink HARQ feedback information received from receiving UEs 1820b-i to BS 1810. Transmitting UE 1820a may transmit the sidelink HARQ feedback information received from receiving UEs 1820b-i to BS 1810 according to the configuration of BS 1810 (i.e., when BS 1810 is configured, the sidelink HARQ feedback information may be transmitted to BS 1810). The sidelink HARQ feedback information may be transmitted through PUCCH or PUSCH.

[0286] For HARQ operation in groupcast, the transmitting UE 1820a should know information about the receiving UEs in the same group. For example, for sidelink HARQ operation, the transmitting UE should identify the sidelink HARQ feedback information sent from different receiving UEs 1820a. That is, the transmitting UE 1820a needs to determine which receiving UE sends HARQ-ACK and which receiving UE sends HARQ-NACK. In addition, the transmitting UE 1820a needs to identify which receiving UE uses the HARQ feedback time / frequency / code resources and which HARQ feedback time / frequency / code resources the receiving UE uses. In order to support the determination and identification by the transmitting UE 1820a, when performing unicast link connection setup between all transmitting UEs 1820a and receiving UEs 1820b-1 to 1820b-N in the same group, or when the transmitting UE receives information about the receiving UEs 1820b-1 to 1820b-N in the group (i.e., group information) from a higher layer of the transmitting UE, it can be applied Figure 18The sidelink HARQ operation method shown in FIG. The group information may include at least one of the number of receiving UEs 1820b-1 to 1820b-N included in the group (or the number of transmitting UEs 1820a and receiving UEs 1820b-1 to 1820b-N included in the group), the ID of transmitting UE 1820a, and the IDs of receiving UEs 1820b-1 to 1820b-N. However, if unicast link connection setup is not performed between all transmitting UEs 1820a and receiving UEs 1820b-1 to 1820b-N in the group, or if the group information is not provided by a higher layer of transmitting UE 1820a, the sidelink HARQ operation method cannot be applied.

[0287] Figure 18 The HARQ operation method in multicast communication is shown, but the operation method can also be applied to unicast communication.

[0288] Figure 19 Another example of a sidelink HARQ operation method in a wireless communication system according to an embodiment of the present disclosure is shown.

[0289] Figure 19 1920b-N according to a sidelink communication procedure in the case of multicast. Receiving UE 1920b-i may be used as an example to describe the operation of a receiving UE or to describe a receiving UE.

[0290] refer to Figure 19 In operation 1901, BS 1910 configures system parameters. Figure 19 In the embodiment, the transmitting UE 1920a and the receiving UEs 1920b-1 to 1920b-N may receive system information for side link communication from the BS 1910. The parameters of the side link communication may be configured in the UEs receiving the system information. When the transmitting UE 1920a and the receiving UEs 1920b-1 to 1920b-N are outside the coverage of the BS 1920 ( Figure 6A out-of-coverage scenario), the transmitting UE 1920a and the receiving UEs 1920b-1 to 1920b-N may receive the configuration of the parameters of the sidelink communication in advance, or may receive the configuration through a sidelink master information block (SL-MIB) sent via a sidelink synchronization channel.

[0291] when Figure 19 When the sidelink HARQ operation method is applied to a multicast communication scenario performed without any PC-5 RRC connection setup, it can be omitted Figure 19The unicast link establishment process between the transmitting UE 1920a and each of the receiving UEs 1920b-1 to 1920b-N is shown. However, when the unicast link establishment process between the transmitting UE 1920a and each of the receiving UEs 1920b-1 to 1920b-N is performed as in operation 1905, the Figure 19 In operation 1905, the transmitting UE 1920a and the receiving UE 1920b-i establish a link. In this scenario, the unicast link establishment process may include Figure 19 In addition, although Figure 19 The unicast link establishment process is shown as being performed after receiving the system parameter configuration information from BS 1910. However, the system parameter configuration information may be received after the unicast link establishment process is performed. If BS 1910 is not present, the sidelink communication parameters may be configured through the SL-MIB after the unicast link establishment process is performed.

[0292] and Figure 18 Differently, the transmitting UE 1920a and the receiving UEs 1920b-1 to 1920b-N can use their own location information for Figure 19 In operation 1903, each of the transmitting UE 1920a and the receiving UEs 1920b-1 to 1920b-N may acquire its own location information. The location information may be an ID of an area including the UE or (x, y) coordinates of the UE calculated by the latitude and longitude of the UE, but is not limited thereto. Figure 19 It is shown that the location information is acquired before the link establishment process, but the embodiment is not limited thereto. That is, after the link is established, the transmitting UE 1920a and the receiving UEs 1920b-1 to 1920b-N can acquire their own location information.

[0293] When Figure 19 Use Figure 12When using the resource allocation method of Mode 1 shown in FIG. 1 , BS 1910 may transmit sidelink scheduling information to multicast transmitting UE 1920a via a downlink control channel (physical downlink control channel (PDCCH)) in operation 1907. In operation 1911, transmitting UE 1920a, which receives the sidelink scheduling information via the PDCCH, may transmit sidelink control information and data information to receiving UEs 1920b-1 to 1920b-N via the PSCCH and PSSCH based on the scheduling information. In this case, sidelink control information (SCI) may be transmitted separately through two operations. The SCI transmitted via the PSCCH may be referred to as the first SCI, and the SCI transmitted via the PSSCH may be referred to as the second SCI. The first SCI and the second SCI may be transmitted via the same sidelink timeslot or different sidelink timeslots. The first SCI and the second SCI may include different pieces of sidelink control information. For example, both a destination identifier (e.g., a destination L2 ID) and a source identifier (e.g., a transmitter L2 ID) may be inserted into the first SCI and transmitted. Alternatively, a destination identifier (e.g., destination L2 ID) may be transmitted via the first SCI, and a source identifier (e.g., transmitter L2 ID) may be inserted into and transmitted in the second SCI. Furthermore, 1-bit information indicating whether the HARQ operation is activated or deactivated may be included in the first SCI or the second SCI. More specifically, even if PSFCH resource configuration information for the HARQ operation (e.g., PSFCH period) is included in the resource pool configuration information, when information indicating deactivation of the HARQ operation is included in the first SCI or the second SCI, the transmitting UE 1920a may deactivate the HARQ operation. The reason for this is described below.

[0294] In the case of broadcast communication, sidelink control information and data information are sent to multiple unspecified UEs, and therefore it may be difficult to operate HARQ in broadcast communication. In the case of unicast and multicast communication, the HARQ operation may or may not be configured according to the QoS of the sidelink data. For example, specific sidelink data has high requirements for reception reliability, and therefore HARQ operation can be configured. However, specific sidelink data has low requirements for reception reliability, and therefore HARQ operation may not be configured. In another example, specific sidelink data has high requirements for the delay time of sidelink communication (i.e., short delay time), and therefore HARQ operation may not be configured. However, specific sidelink data has low requirements for delay time (i.e., long delay time is not a problem), and therefore HARQ operation may be configured. As described above, the HARQ operation can be configured or released according to the QoS of the sidelink data sent by the transmitting UE 1920a. Since whether to configure the HARQ operation can vary according to the QoS, the configuration can be performed by the V2X layer that receives the QoS from the application layer or the application that manages the QoS.

[0295] However, in this case, HARQ operation of receiving UE 1920-i may not be possible. More specifically, HARQ operation should be performed by the PHY / MAC layer. However, if the HARQ operation is managed by the V2X layer or the application layer, the PHY / MAC layer of receiving UE 1920b-i cannot perform HARQ operation. That is, the PHY / MAC layer of receiving UE 1920b-i should identify whether HARQ is operated before sending the corresponding packet to the V2X layer or the application layer of the receiving UE, and the receiving UE 1920b-i can perform HARQ combined with the PHY layer on this basis. Therefore, for the HARQ operation of the PHY / MAC layer, the transmitting UE 1920a can include a 1-bit indicator indicating whether HARQ is operated in the first SCI or the second SCI.

[0296] At the same time, if Figure 13 As shown, it can be Figure 19 In this case, the resource allocation method of mode 2 is used. Figure 19 different, Figure 19 The operation of the transmitting UE 1920a receiving scheduling information from the BS 1910 through the PDCCH (operation 1907) may be omitted.

[0297] When the first SCI of the PSCCH transmitted from transmitting UE 1920a indicates the destination L2 ID of the receiving UE, receiving UE 1920b-i may decode the PSSCH. At this time, receiving UE 1920b-i may transmit each of HARQ-ACK and HARQ-NACK to transmitting UE 1920a or transmit only HARQ-NACK to transmitting UE 1920a, depending on the HARQ feedback method and whether the decoding of the PSSCH is successful (indicated by the received first SCI or second SCI). For example, when the HARQ feedback method of transmitting each of HARQ-ACK and HARQ-NACK to transmitting UE 1920a is indicated by the first SCI or the second SCI, receiving UE 1920b-i may transmit HARQ-ACK to transmitting UE 1920a if the PSSCH decoding is successful, and transmit HARQ-NACK to transmitting UE 1920a if the PSSCH decoding fails. On the other hand, when transmitting UE 1920a indicates the HARQ feedback method of sending only HARQ-NACK in the first SCI or the second SCI, receiving UE 1920b-i may send HARQ-NACK to transmitting UE 1920a only when PSCCH decoding fails. That is, when PSSCH decoding is successful, receiving UE 1920b-i may not send HARQ-ACK to transmitting UE 1920a.

[0298] The transmitting UE 1920a may explicitly or implicitly indicate a HARQ feedback method of sending only HARQ-NACK through the first SCI or the second SCI. In addition, the transmitting UE 1920a may send its own location information range requirement of the side link data packet sent by the transmitting UE through the second SCI. The range requirement is not limited to reception through the SCI, and a value pre-configured in the UE or a value configured by the BS 1910 may be used. Alternatively, the total number of range requirements may be X, and Y of the X range requirements may be included in the side link resource pool information through configuration or pre-configuration (X>Y) of the BS 1910. One of the configured or pre-configured Y values ​​may be sent to the receiving UE 1920b-i through the first or second SCI.

[0299] The location information of the transmitting UE 1920a may be, but is not limited to, the ID of the area in which the transmitting UE 1920a is located or the (x, y) coordinates of the transmitting UE 1920a calculated using the latitude and longitude of the transmitting UE 1920a. The requirement may be expressed in meters and may refer to distance information for transmitting sidelink data packets. For example, the range requirement may be at least one of a maximum or minimum distance for transmitting sidelink data packets.

[0300] Receiving UEs 1920b-1 to 1920b-N that receive the PSCCH and PSSCH from transmitting UE 1920a can determine whether the destination L2 ID included in the first SCI indicates the receiving UE. When the destination ID included in the first SCI indicates the receiving UE, receiving UE 1920b-i can decode the second SCI and decode the PSSCH using the time and / or frequency resource allocation information of the PSSCH included in the second SCI (the time and / or frequency resource allocation information of the PSSCH is included in the second SCI). In another example, when the destination ID included in the first SCI indicates the receiving UE, receiving UE 1920b-i can decode the PSSCH using the time and / or frequency resource allocation information of the PSSCH included in the first SCI (the time and / or frequency resource allocation information of the PSSCH is included in the first SCI).

[0301] After decoding the PSSCH, the receiving UE 1920b-i can ultimately determine whether to transmit sidelink data to the receiving UE itself using the destination L2 ID included in the MAC-CE transmitted via the PSSCH. That is, the destination L2 ID may consist of N bits, and N1 bits may be transmitted via the first SCI or the second SCI, and N2 bits may be transmitted via the MAC-CE (N=N1+N2). When the destination L2 ID included in the received SCI does not indicate the receiving UE, the receiving UE 1920b-i may not decode the PSSCH indicated by the corresponding SCI.

[0302] In operation 1913, receiving UE 1920b-i may compare the distance between receiving UE 1920b-i and transmitting UE 1920a with a threshold value. That is, each of receiving UEs 1920b-i to 1920b-N may calculate the distance between the receiving UE and transmitting UE 1920a and compare the calculated distance with the threshold distance included in the range requirement.

[0303] When the first SCI transmitted from the transmitting UE 1920a indicates the destination L2 ID of the receiving UE 1920b-i, the receiving UE 1920b-i can calculate the distance between the transmitting UE 1920a and itself (i.e., the receiving UE 1920b-i) by using its own location information and the location information of the transmitting UE 1920a included in the first or second SCI. For example, the distance between the transmitting UE 1920a and the receiving UE 1920b-N can be defined as d N In addition, the receiving UE 1920b-N may include a range requirement (defined as d TH) to compare d TH and d N The receiving UE 1920b-N can receive the TH with d N The HARQ operation is performed based on the comparison result between them.

[0304] When the measured (calculated or obtained) distance between the transmitting UE 1920a and the receiving UE is greater than (or equal to) the range requirement, the receiving UE 1920b-i may not send HARQ feedback information to the transmitting UE 1920a regardless of whether the decoding of the PSSCH received by the receiving UE is successful. N >d TH or d N ≥d TH In the case of d, the receiving UE 1920b-i may not send HARQ feedback. N ≤d TH or d N <d TH In the case of a distance condition, receiving UE 1920b-i may send HARQ feedback to transmitting UE 1920a. In addition, receiving UE 1920b-i may send HARQ-ACK to transmitting UE 1920a only when PSSCH decoding fails. In other words, even if the distance condition is met, HARQ-ACK may not be sent to transmitting UE 1920a when PSSCH decoding succeeds. Figure 19 An example of a case where receiving UE 1920b-i transmits a HARQ-NACK to transmitting UE 1920a via the PSFCH is shown. In operation 1915, only receiving UE 1920b-i may transmit a HARQ-NACK to transmitting UE 1920a via the PSFCH, while other UEs (e.g., UEs 1920b-2 to 1920b-N) may not transmit HARQ feedback information to transmitting UE 1920a.

[0305] When two or more receiving UEs meet the conditions (i.e., d N ≤d TH or N <d TH) and PSSCH decoding fails, two or more receiving UEs may send HARQ-NACK to the transmitting UE 1920. At this time, the PSFCH time / frequency / code resources used by the two or more receiving UEs for HARQ-NACK transmission may be the same. Therefore, the transmitting UE 1920a that receives the HARQ feedback information does not need to know how many receiving UEs have sent NACK information, and the transmitting UE 1920a that receives the NACK information may retransmit the PSSCH. When the transmitting UE 1920a does not receive the NACK information and generates new sidelink data to be transmitted, the transmitting UE 1920a may send a new PSSCH. When new sidelink data to be transmitted is not generated, the transmitting UE 1920a may stop the PSSCH transmission operation.

[0306] In operation 1917, the transmitting UE 1920a may transmit the sidelink HARQ feedback information received from the receiving UEs 1920b-i to the BS 1910. The transmitting UE 1920a may transmit the sidelink HARQ feedback information received from the receiving UEs 1920b-i to the BS 1910 according to the configuration of the BS 1910. The sidelink HARQ feedback information may be transmitted through the PUCCH or the PUSCH.

[0307] Indicates whether to use in multicast communication Figure 18 Sidelink HARQ operation or Figure 19 The information of the sidelink HARQ operation of the BS 1910 may be included in the resource pool configuration information configured by the BS 1910, or when the BS 1910 does not exist, may be included in the pre-configured resource pool configuration information. In another example, whether to apply Figure 18 and Figure 19 The first SCI or the second SCI may be implicitly or explicitly indicated by the transmitting UE 1920a. In the example of implicit indication, when the location information and range requirement information of the transmitting UE 1920a are included in the SCI, the receiving UEs 1920b-i may indirectly identify the location of the receiving UE 1920a. Figure 19 When the location information and range requirement information of the sending UE 1920a are not included in the SCI, the receiving UE 1920b-i can indirectly identify Figure 18 In the example of explicit indication, the transmitting UE 1920a may insert a 1-bit indicator into the first SCI or the second SCI and transmit the first SCI or the second SCI. The UE receiving the SCI may apply the Figure 18 method, and applies when the indicator indicates "0" Figure 19 According to the configuration, when the indicator indicates "0", it can be applied Figure 18method, and can be applied when the indicator indicates "1" Figure 19 method.

[0308] Figure 19 The HARQ operation method in multicast communication is shown, but the operation method can also be applied to unicast communication.

[0309] Figure 20 An example of a method of using an area identifier (ID) in a wireless communication system according to an embodiment of the present disclosure is shown.

[0310] refer to Figure 20 , the BS can send zone configuration information to the sidelink UE in the cell through the SL-ZoneConfig information element (IE) of the sidelink system information. The SL-ZoneConfig IE can include a zoneWidth parameter ( Figure 20 W in the zone), the zoneLength parameter indicating the length of the zone ( Figure 20 In the L), the zoneIdLongiMod parameter that indicates the total number of zones based on longitude, and the zoneIdLatiMod parameter that indicates the total number of zones based on latitude. Each of the zoneWidth and zoneLength parameters can be configured to be one of 5m, 10m, 20m, 30m, 40m, and 50m. In this case, zoneWidth and zoneLength can be configured to the same value (i.e., zoneWidth=zoneLength∈{5m,10m,20m,30m,40m,50m}). In addition, each of the zoneIdLongiMod and zoneIdLatiMode parameters can be configured to an integer from 1 to 64. That is, in Figure 20 In the zone 2000 with a width of Akm and a length of Bkm, the parameters in the SL-ZoneConfigIE configured by the BS (pre-configured when no BS exists) can be used to configure the width and length (W, L) of each zone and how many zones are included in (A×B)km.

[0311] At the same time, if Figure 19As shown, the range requirement of the sidelink data packet can be configured in the sidelink resource pool (configured by the BS or pre-configured when the BS does not exist). There can be 32 range requirements, such as {20, 50, 80, 100, 120, 150, 180, 200, 220, 250, 270, 300, 320, 350, 370, 400, 420, 450, 480, 500, 550, 600, 700, 1000, empty, empty, empty, empty, empty, empty, empty, empty}, and 16 of the 32 range requirements can be configured in the sidelink resource pool. The sending UE can receive the range requirement of the sidelink data packet sent by the sending UE from the higher layer, and the higher layer can provide one of the 16 range requirements configured in the sidelink resource pool. The sidelink sending UE can send the range requirement to the receiving UE through the 4-bit field of the first or second SCI. In this example, the side link resource pool may be a side link transmission resource pool, a side link reception resource pool, or both a transmission resource pool and a reception resource pool.

[0312] Meanwhile, when the BS configures two or more sidelink resource pools (when two or more sidelink transmission resource pools are pre-configured in the absence of the BS), different range requirements and area sizes (W and L, where W=L) can be configured in the corresponding resource pools. For example, since the speed of the sidelink UE in the area where the highway is located (i.e., the speed of the vehicle) is high, the time point at which the transmitting UE sends its own area ID and the time point at which the receiving UE receives the area ID and performs Figure 19 The location at the time of the HARQ operation shown may change rapidly. Therefore, in this case, when the area size is small, the error in calculating the distance using the area ID may increase, and therefore it is necessary to configure the area size to be larger. On the other hand, in the case of a downtown area, the speed of the sidelink UE (i.e., the speed of the vehicle) is not fast, and therefore the accuracy of the HARQ operation can be improved by configuring the area size to be smaller.

[0313] In another example, when the range requirement is small (e.g., 20m), the region size cannot be large. In this case, the accuracy of HARQ operation can be improved by keeping the region size small. On the other hand, when the range requirement is large (e.g., 500m), if the region size is too small, the signaling overhead for indicating different region sizes may increase significantly. In this case, the signaling overhead can be reduced by keeping the region size at an appropriate size.

[0314] Through the above example, different area sizes and range requirements can be configured (pre-configured) for each side link resource pool, and it can be noted that there is a correlation between the range requirement and the area size. Therefore, when configuring multiple resource pools, the sending UE can configure the sending resource pool considering the range requirements of the side link data packets to be sent by the sending UE. For example, range requirements such as 16 values ​​{20, 50, 80, 100, 120, 150, 180, 200, 220, 250, 270, 300, 320, 350, 370, 400} can be configured in side link resource pool A. In addition, range requirements such as 16 values ​​{420, 450, 480, 500, 550, 600, 700, 1000, empty, empty, empty, empty, empty, empty, empty, empty} can be configured in side link resource pool B. At this time, when the requirement of the side link data packet to be sent by the sending UE corresponds to 300m, the sending UE can select resource pool A.

[0315] In an example, resource pool A and resource pool B include different range requirements. On the other hand, resource pool A and resource pool B may include the same range requirement. For example, a range requirement such as 16 values ​​{20, 50, 80, 100, 120, 150, 180, 200, 220, 250, 270, 300, 320, 350, 370, 400} may be configured in sidelink resource pool C. In addition, a range requirement such as 16 values ​​{350, 370, 400, 420, 450, 480, 500, 550, 600, 700, 1000, empty, empty, empty, empty, empty} may be configured in sidelink resource pool D. In this case, the transmitting UE may randomly select one of resource pool C and resource pool D. In another example, the transmitting UE may randomly select one of resource pool C and resource pool D by referring to Figure 15 A sending resource pool is selected using at least one of the methods described.

[0316] According to one embodiment of the present disclosure, a method for operating a user equipment (UE) in a wireless communication system includes: obtaining configuration information of multiple side link resource pools; and using one of the multiple side link resource pools to send a side link signal to another UE, wherein the multiple side link resource pools are configured within an equal bandwidth part (BWP).

[0317] According to one embodiment, one resource pool is selected based on at least one of characteristics related to the sidelink data or service, characteristics of the plurality of sidelink resource pools, channel quality, or a state of the UE.

[0318] According to one embodiment, the multiple sidelink resource pools include a first resource pool including a feedback channel and a second resource pool not including a feedback channel.

[0319] According to one embodiment, the feedback channel is included in some time slots belonging to the first resource pool.

[0320] According to one embodiment, the feedback channel includes some bandwidth occupied by the first resource pool.

[0321] According to one embodiment, the plurality of sidelink resource pools include at least two of a first resource pool for unicast communication, a second resource pool for multicast communication, or a third resource pool for broadcast communication.

[0322] According to one embodiment, a resource pool is selected based on the type of communication the UE desires to perform.

[0323] According to one embodiment, the plurality of sidelink resource pools have a first resource pool including a feedback channel and a second resource pool not including a feedback channel, and wherein one resource pool is selected based on whether hybrid automatic repeat request (HARQ) feedback is operated.

[0324] According to one embodiment, the plurality of sidelink resource pools include at least one time slot that does not overlap on the time axis, and one of the resource pools is selected as the resource pool including the resource pool located first on the time axis after the sidelink data is generated.

[0325] According to one embodiment, wherein a plurality of sidelink resource pools are configured to correspond to a range of different channel qualities, and wherein a resource pool is selected based on the channel quality between the BS and the UE or the channel quality between the UE and another UE.

[0326] According to one embodiment, the method further comprises receiving information regarding ranges of channel qualities corresponding to the plurality of sidelink resource pools.

[0327] According to one embodiment, a resource pool is selected based on a congestion level determined based on all resources of a plurality of sidelink resource pools and resources occupied by other UEs.

[0328] According to one embodiment, a resource pool is selected based on the quality of service (QoS) of the sidelink service.

[0329] According to one embodiment, a user equipment (UE) in a wireless communication system includes: a transceiver; and at least one processor, which is operably coupled to the transceiver, wherein the at least one processor is configured to control to: obtain configuration information of multiple side link resource pools; and use one of the multiple side link resource pools to send a side link signal to another UE, wherein the multiple side link resource pools are configured using equal bandwidth parts (BWP).

[0330] According to one embodiment, one resource pool is selected based on at least one of characteristics related to the sidelink data or service, characteristics of the plurality of sidelink resource pools, channel quality, or a state of the UE.

[0331] According to one embodiment, the multiple sidelink resource pools include at least two of a first resource pool for unicast communication, a second resource pool for multicast communication, or a third resource pool for broadcast communication, and wherein a resource pool is selected based on the type of communication the UE expects to perform.

[0332] According to one embodiment, the plurality of sidelink resource pools have a first resource pool including a feedback channel and a second resource pool not including a feedback channel, and wherein one resource pool is selected based on whether hybrid automatic repeat request (HARQ) feedback is operated.

[0333] According to one embodiment, the plurality of sidelink resource pools include at least one time slot that does not overlap on the time axis, and one of the resource pools is selected as the resource pool including the resource pool located first on the time axis after the sidelink data is generated.

[0334] According to one embodiment, wherein a plurality of sidelink resource pools are configured to correspond to a range of different channel qualities, and wherein a resource pool is selected based on the channel quality between the BS and the UE or the channel quality between the UE and another UE.

[0335] According to one embodiment, a resource pool is selected based on a congestion level determined based on all resources of a plurality of sidelink resource pools and resources occupied by other UEs.

[0336] According to one embodiment, a resource pool is selected based on the quality of service (QoS) of the sidelink service.

[0337] In addition, the PSFCH, PSCCH, and PSSCH included in the present disclosure refer to physical channels of NR or LTE and are not limited to any one.

[0338] The methods disclosed in the claims and / or the methods according to the embodiments described in the specification of the present disclosure may be implemented by hardware, software, or a combination of hardware and software.

[0339] When the method is implemented by software, a computer-readable storage medium for storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium may be configured to be executed by one or more processors within the electronic device. At least one program may include instructions that cause the electronic device to perform the method defined by the appended claims and / or disclosed herein according to various embodiments of the present disclosure.

[0340] The program (software module or software) can be stored in a non-volatile memory, including random access memory and flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic disk storage, compact disc-ROM (CD-ROM), digital versatile disc (DVD) or other types of optical storage devices, or magnetic tape cassettes. Alternatively, any combination of some or all of them can form the memory storing the program. In addition, multiple such memories may be included in the electronic device.

[0341] Alternatively, the program may be stored in an attachable storage device that can access the electronic device via a communication network such as the Internet, an intranet, a local area network (LAN), a wide area LAN (WLAN), and a storage area network (SAN), or a combination thereof. Such a storage device can access the electronic device via an external port. Furthermore, a separate storage device on a communication network can access the portable electronic device.

[0342] In the above detailed embodiments of the present disclosure, the elements included in the present disclosure are expressed in the singular or plural, depending on the detailed embodiment presented. However, for ease of description, the singular form or plural form is appropriately selected for the situation presented, and the present disclosure is not limited to elements expressed in the singular or plural. Therefore, an element expressed in the plural may also include a single element, or an element expressed in the singular may also include multiple elements.

[0343] While the present disclosure has been shown and described with reference to various embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the appended claims and their equivalents.

Claims

1. A method performed by a user equipment (UE) supporting a New Radio (NR) side link and a Long Term Evolution (LTE) side link, the method comprising: receiving, from a base station BS, system information for a plurality of sidelink resource pools, the plurality of sidelink resource pools including a first sidelink resource pool and a second sidelink resource pool; receiving downlink control information (DCI) from the BS; identifying, based on a radio network temporary identifier (RNTI), whether the DCI is a first DCI for the NR side link or a second DCI for the LTE side link; as well as sending a sidelink signal based on the DCI and one of the first sidelink resource pool or the second sidelink resource pool, The first side link resource pool includes resources for a feedback channel. wherein the second sidelink resource pool does not include resources for a feedback channel, and The first DCI is detected based on the first RNTI used for the NR side link, and the second DCI is detected based on the second RNTI used for the LTE side link.

2. The method according to claim 1, in, The second DCI includes time setting offset information of an offset value between an NR time slot for receiving the DCI and an LTE subframe to which the DCI is to be applied.

3. The method according to claim 1, in, The first DCI includes an indicator indicating activation or release of a semi-persistent scheduling (SPS) for the NR sidelink, and The second DCI includes an indicator indicating activation or release of the SPS for the LTE side link.

4. The method according to claim 1, in, In a case where the plurality of sidelink resource pools are associated with a transmission resource pool, a physical sidelink control channel PSCCH or a physical sidelink shared channel PSSCH is transmitted using one sidelink resource pool selected from the plurality of sidelink resource pools, and In the case where the multiple side link resource pools are associated with a receiving resource pool, the PSCCH or the PSSCH is received using the multiple side link resource pools.

5. A method performed by a base station (BS) supporting a New Radio (NR) side link and a Long Term Evolution (LTE) side link, the method comprising: Sending system information for a plurality of sidelink resource pools to a user equipment (UE), the plurality of sidelink resource pools including a first sidelink resource pool and a second sidelink resource pool; as well as Sending downlink control information DCI to the UE, The DCI is identified as the first DCI for the NR side link or the second DCI for the LTE side link based on a radio network temporary identifier (RNTI). The first side link resource pool includes resources for a feedback channel. wherein the second sidelink resource pool does not include resources for the feedback channel, and The first DCI is detected based on the first RNTI used for the NR side link, and the second DCI is detected based on the second RNTI used for the LTE side link.

6. The method according to claim 5, in, The second DCI includes information of an offset value between an NR time slot for receiving the DCI and an LTE subframe to which the DCI is to be applied.

7. The method according to claim 5, in, The first DCI includes an indicator indicating activation or release of a semi-persistent scheduling (SPS) for the NR sidelink, and The second DCI includes an indicator indicating activation or release of the SPS for the LTE side link.

8. The method according to claim 5, in, In a case where the plurality of sidelink resource pools are associated with a transmission resource pool, a physical sidelink control channel PSCCH or a physical sidelink shared channel PSSCH is transmitted using a sidelink resource pool selected from the plurality of sidelink resource pools, and In the case where the multiple side link resource pools are associated with a receiving resource pool, the PSCCH or the PSSCH is received using the multiple side link resource pools.

9. A user equipment (UE) supporting a New Radio (NR) side link and a Long Term Evolution (LTE) side link, the UE comprising: transceiver; as well as A controller is coupled to the transceiver and configured to perform the method according to any one of claims 1 to 4.

10. A base station (BS) supporting a New Radio (NR) side link and a Long Term Evolution (LTE) side link, the BS comprising: transceiver; as well as A controller is coupled to the transceiver and configured to perform the method according to any one of claims 5 to 8.

Images