Method and apparatus for controlling sidelink in communication system

Abstract

A method performed by a first user equipment according to an embodiment of the present invention comprises the steps of: performing resource allocation for sidelink (SL) communication; generating SCI on the basis of the allocated resource; and transmitting a PSCCH including the SCI to a neighboring second UE, wherein the SCI may include frequency information of a resource allocated to a packet to be subsequently transmitted and subframe index information of the resource allocated to the packet to be subsequently transmitted.

Description

Method and apparatus for controlling a side link in a communication system

[0001] The present disclosure describes a method and apparatus for controlling a sidelink (SL) in a communication system.

[0002] With the advancement of autonomous driving technology, the development of Cooperative-intelligent Transport Systems (C-ITS) is actively underway. Vehicle-to-everything (V2X) communication technology has established itself as the most critical technology in C-ITS. However, V2X communication requires low latency and high reliability, and Quality of Service (QoS) requirements vary for each application.

[0003] In this regard, the 3GPP (The 3rd generation partnership project) is proceeding with the standardization of V2X communication technology. To provide high communication QoS for V2X, it is essential to solve the radio resource management (RRM) problem.

[0004] To manage such wireless resources, research is being conducted on a method that enables each vehicle to independently allocate resources via a sidelink, allowing vehicles to freely utilize resources allocated from the upper network to perform V2X communication.

[0005] However, regarding the utilization of side links, there are centralized and distributed resource allocation methods; when the distributed method is adopted for low-latency services, a problem arises where QoS degrades due to unexpected interference within resources and packet collisions. In particular, in half-duplex (HD) communication, packet collisions between terminals can occur if an error occurs, and a method to prevent this is required.

[0006] The present disclosure aims to provide new control information for improving communication quality in a side link.

[0007] The present disclosure aims to provide improved communication quality and performance by reducing interference and packet collisions through a side link resource allocation algorithm.

[0008] A method performed by a first user device according to various aspects of the present disclosure comprises: performing resource allocation for side link communication; generating side link control information based on the allocated resources; and transmitting a PSCCH including the SCI to an adjacent second UE, wherein the SCI may include frequency information of the resources allocated to a packet to be subsequently transmitted and subframe index information of the resources allocated to the packet to be subsequently transmitted.

[0009] In one embodiment, the SCI may further include priority information, resource reservation interval information, frequency resource location information of the currently transmitted packet, time gap information, modulation coding scheme information, and retransmission index information.

[0010] In one embodiment, the frequency information of the resource allocated to the subsequent packet to be transmitted can be expressed in the same way as the frequency resource location information of the currently transmitted packet.

[0011] In one embodiment, the subframe index information of the resource allocated to the subsequent packet to be transmitted may include information regarding the difference between the subframe of the currently transmitted packet and the subframe of the subsequent packet to be transmitted.

[0012] In one embodiment, when the currently transmitted packet is transmitted at the nth, the subsequent packet to be transmitted may be transmitted at the n+1th.

[0013] In one embodiment, the SCI may be configured with a size of 32 bits, frequency information of the resource allocated to the subsequent packet to be transmitted may be configured with a size of 4 bits, and subframe information of the resource allocated to the subsequent packet to be transmitted may be configured with a size of 7 bits.

[0014] In one embodiment, when the resource allocated to the packet to be subsequently transmitted and the resource allocated to the packet currently being transmitted are the same, the frequency information of the resource allocated to the packet to be subsequently transmitted and the subframe index information value of the resource allocated to the packet to be subsequently transmitted may be determined to be 0.

[0015] A method performed by a second user device according to various aspects of the present disclosure comprises: receiving a PSCCH including an SCI from an adjacent first UE; and performing resource allocation for performing side link communication based on the SCI, wherein the SCI may include frequency information of a resource allocated to a packet to be subsequently transmitted and subframe index information of a resource allocated to a packet to be subsequently transmitted.

[0016] In one embodiment, the step of performing the resource allocation may further include the step of decoding the SCI; and the step of identifying frequency information of the resource allocated to the subsequent packet to be transmitted and subframe index information of the resource allocated to the subsequent packet to be transmitted from the decoded SCI.

[0017] In one embodiment, the step of performing the resource allocation may include excluding resources already reserved among the resources available for the side link communication based on frequency information of the resources allocated to the identified subsequent packet to be transmitted and subframe index information of the resources allocated to the subsequent packet to be transmitted.

[0018] In one embodiment, the step of performing the resource allocation may include the step of performing resource allocation by selecting resources among the resources from which the reserved resources are excluded that have an RSSI value lower than a predetermined value.

[0019] A first user device according to various aspects of the present disclosure comprises: a memory; a transceiver; and a processor connected to the transceiver and the memory, wherein the processor is configured to perform resource allocation for sidelink (SL) communication, generate sidelink control information (SCI) based on the allocated resources, and transmit a physical sidelink control channel (PSCCH) containing the SCI to an adjacent second UE, wherein the SCI may include frequency information of the resources allocated to a packet to be subsequently transmitted and subframe index information of the resources allocated to a packet to be subsequently transmitted.

[0020] In a second user device according to various aspects of the present disclosure, the device comprises: a memory; a transceiver; and a processor connected to the transceiver and the memory, wherein the processor is configured to receive a physical sidelink control channel (PSCCH) including an SCI from an adjacent first UE and to perform resource allocation for performing sidelink communication based on the SCI, and the SCI may include frequency information of a resource allocated to a packet to be subsequently transmitted and subframe index information of a resource allocated to a packet to be subsequently transmitted.

[0021] According to one embodiment of the present disclosure, packet collisions can be prevented and communication quality improved while maintaining the existing format without changing the hardware.

[0022] According to one embodiment of the present disclosure, communication problems for hidden / exposed vehicles can be resolved by performing resource allocation in consideration of subsequent transmissions in V2X or side link communication.

[0023] A brief description of each drawing is provided to help to better understand the drawings cited in the detailed description of the present disclosure.

[0024] FIG. 1 shows a system for performing V2X or SL communication according to one embodiment of the present disclosure.

[0025] FIG. 2 illustrates a procedure in which a terminal performs SL communication according to one embodiment of the present disclosure.

[0026] FIG. 3 may show the format structure of an SCI according to one embodiment of the present disclosure.

[0027] FIG. 4 is a diagram illustrating a scenario in which packet collisions occur when resource allocation is performed based on SCI according to one embodiment of the present disclosure.

[0028] FIG. 5 may show a new format structure of SCI according to one embodiment of the present disclosure.

[0029] FIG. 6 is a diagram illustrating a scenario in which resource allocation is performed based on a modified SCI according to one embodiment of the present disclosure to avoid packet collisions.

[0030] FIG. 7 illustrates a method for allocating resources based on SCI and RSSI according to one embodiment of the present disclosure.

[0031] FIG. 8 is a flowchart illustrating a process in which a UE performs resource allocation by avoiding packet collisions according to one embodiment of the present disclosure.

[0032] FIG. 9 is a flowchart illustrating a process in which a UE performs resource allocation based on SCI according to one embodiment of the present disclosure.

[0033] FIG. 10 is a block diagram of a UE according to one embodiment of the present disclosure.

[0034] FIG. 11 is a flowchart illustrating a method for performing SL communication in a UE according to one embodiment of the present disclosure.

[0035] FIG. 12 is a flowchart illustrating a method for performing SL communication based on SCI in a UE according to one embodiment of the present disclosure.

[0036]

[0037] The technical concept of the present disclosure is subject to various modifications and may have various embodiments. Specific embodiments are illustrated in the drawings and described in detail through the detailed description. However, this is not intended to limit the technical concept of the present disclosure to specific embodiments, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the scope of the technical concept of the present disclosure.

[0038] In describing the technical concept of the present disclosure, detailed descriptions of related prior art are omitted if it is determined that such descriptions may unnecessarily obscure the essence of the present invention. Furthermore, numbers used in the description of this specification (e.g., first, second, etc.) are merely identification symbols to distinguish one component from another.

[0039] In addition, when a component is described in this specification as being "connected" or "connected" to another component, it should be understood that the component may be directly connected to or directly connected to the other component, but unless otherwise specifically stated, it may also be connected or connected through another component in between.

[0040] In addition, terms such as “~part,” “~device,” “~device,” and “~module” described in this specification refer to a unit that processes at least one function or operation, and may be implemented as hardware or software or a combination of hardware and software such as a processor, microprocessor, microcontroller, CPU (Central Processing Unit), GPU (Graphics Processing Unit), APU (Accelerate Processor Unit), DSP (Drive Signal Processor), ASIC (Application Specific Integrated Circuit), and FPGA (Field Programmable Gate Array), and may also be implemented in a form combined with memory that stores data necessary for processing at least one function or operation.

[0041] Furthermore, it is intended to clarify that the classification of components in this specification is merely based on the primary function each component is responsible for. That is, two or more components described below may be combined into a single component, or a single component may be divided into two or more components based on more subdivided functions. Additionally, each component described below may additionally perform some or all of the functions of other components in addition to the primary function it is responsible for, and it is obvious that some of the primary functions of each component may be exclusively performed by other components.

[0042] In describing the embodiments of the present disclosure, specific descriptions of related functions or configurations are omitted if it is determined that such detailed descriptions would unnecessarily obscure the essence of the present disclosure. Furthermore, terms used below are defined in consideration of their functions within the present disclosure, and these definitions may vary depending on the intent or practices of the user or operator. Therefore, such definitions should be based on the content throughout this specification.

[0043] For the same reason, some components in the attached drawings may be exaggerated, omitted, or schematically depicted. Additionally, the size of each component does not entirely reflect its actual size. Identical or corresponding components in each drawing have been assigned the same reference number.

[0044] The advantages and features of the present disclosure and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below but may be implemented in various different forms. The embodiments are provided merely to make the description of the present disclosure complete and to fully inform those skilled in the art of the scope of the invention, and the scope of the claims of the present disclosure is defined only by the scope of the claims.

[0045] At this point, it will be understood that each block of the drawings showing the process flow diagram and the combinations of the process flow diagrams can be executed by computer program instructions. Since these computer program instructions can be loaded into the processor of a general-purpose computer, a specialized computer, or other programmable data processing equipment, the instructions executed through the processor of the computer or other programmable data processing equipment create means to perform the functions described in the flow diagram block(s). Since these computer program instructions can also be stored in computer-available or computer-readable memory that can be directed toward the computer or other programmable data processing equipment to implement the function in a specific way, the instructions stored in computer-available or computer-readable memory can also produce a manufactured item containing the means of instruction to perform the function described in the flow diagram block(s). Since computer program instructions can be loaded onto a computer or other programmable data processing equipment, instructions that perform a series of operation steps on the computer or other programmable data processing equipment to create a process executed by the computer can also provide steps for executing the functions described in the flowchart block(s).

[0046] Additionally, each block may represent a module, segment, or part of code containing one or more executable instructions for executing a specified logical function(s). It should also be noted that in some alternative execution examples, the functions mentioned in the blocks may occur out of order. For instance, two blocks described in succession may actually be executed substantially simultaneously, or the blocks may be executed in reverse order according to their corresponding functions.

[0047] As used in this disclosure, the term “unit or part” refers to a software or hardware component, such as a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC), and the “part” may be configured to perform specific roles. However, the “part” is not limited to software or hardware. The “part” may be configured to reside in an addressable storage medium or to execute one or more processors. Thus, by example, the “part” includes components such as software components, object-oriented software components, class components, and task components, as well as processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and “parts” may be combined into a smaller number of components and “parts” or further separated into additional components and “parts.” In addition, the components and 'parts' may be implemented to utilize one or more CPUs within the device or secure multimedia card. Also, in the embodiments, 'parts' may include one or more processors and / or devices.

[0048]

[0049] Hereinafter, embodiments according to the technical concept of the present disclosure will be described in detail in turn.

[0050]

[0051] FIG. 1 shows a system for performing V2X or SL communication according to one embodiment of the present disclosure.

[0052] Referring to FIG. 1, the V2X or SL communication system (100) may include a roadside base station (roadside unit: RSU) (105) and a plurality of user equipment (110, 120).

[0053] In V2X or SL communication systems, the term user equipment (UE) can primarily refer to a user's terminal. That is, it can be used to refer to the pedestrian terminal (hereinafter, pedestrian) (120) itself. However, if network equipment such as an RSU (105) transmits and receives signals according to the communication method between terminals, the RSU (105) may also be considered a type of terminal. Additionally, the UE may refer to the vehicle itself as a VUE (Vehicle user equipment) (110) or to a communication terminal included in the vehicle. For example, the first UE (110) may be a vehicle, and the second UE (120) may be a pedestrian.

[0054]

[0055] In one embodiment, according to a distributed resource allocation method, the terminal can discover resources through monitoring and collect RSSI to allocate resources itself. For example, an RSU (105), a vehicle (110), or a pedestrian (120) can identify resources for SL communication through monitoring and can perform communication by allocating appropriate resources themselves.

[0056] Additionally, the vehicle (110) can select a resource unit corresponding to a specific resource within a resource pool, which is a set of resources allocated for side link communication. And, the vehicle (110) can transmit an SL signal using the said resource unit.

[0057]

[0058] Generally, communication resources can be composed of multiple resource units, and each terminal can select one or more resource units to use for V2X or SL signal transmission.

[0059] The following describes resource allocation methods in V2X or SL communication.

[0060]

[0061] FIG. 2 illustrates a procedure in which a terminal performs SL communication according to one embodiment of the present disclosure.

[0062] Referring to FIG. 2, the first UE (210) can determine and allocate SL transmission resources within SL resources or preset SL resources set by the base station / upstream network. In another embodiment, the set SL resources or preset SL resources may be resource pools. For example, a terminal can perform SL communication by selecting a resource itself from a preset resource pool.

[0063] And, the first UE (210) can transmit a PSCCH (physical sidelink control channel) (230) to the second UE (220). The PSCCH may include SCI (sidelink control information), which is information for controlling the sidelink.

[0064] FIG. 3 may show the format structure of an SCI according to one embodiment of the present disclosure. The SCI is transmitted in a total of two stages, wherein the SCI may be a 1-stage SCI transmitted in the first stage.

[0065] Referring to FIG. 3, the SCI format (300) may include a priority field (310), a resource reservation interval (RRI) field (320), a frequency resource location field (330), a time gap field (340), a modulation coding scheme (MCS) field (350), a retransmission (ReTx) index field (360), and a reservation field (370).

[0066] The SCI format (300) may have a size of 32 bits. In the SCI format (300), the priority field (310) may be 3 bits, the resource reservation interval field (320) may be 4 bits, the frequency resource location field (330) may be 4 bits, the time gap field (340) may be 4 bits, the modulation coding scheme field (350) may be 5 bits, the retransmission index field (360) may be 1 bit, and the reservation field (370) may be 11 bits.

[0067] Each field of the priority field (310) to the retransmission index field (360) contains the same content as the techniques conventionally used to control side links and is not further described in this disclosure.

[0068] Here, the reservation field (370) may be a field left empty for future use, and in one embodiment, may include information to indicate whether the resource transmitted through the SCI is reserved for the next transmission.

[0069] Returning to Fig. 2, the first UE (210) can transmit data prepared based on the SCI to the second UE (220) via the PSSCH (physical sidelink shared channel) (240).

[0070] At this time, PSCCH (230) and PSSCH (240) may be transmitted together, or in some cases, sequentially.

[0071]

[0072] FIG. 4 is a diagram illustrating a scenario in which packet collisions occur when resource allocation is performed based on SCI according to one embodiment of the present disclosure.

[0073] The SCI transmitted in Fig. 4 may be the same or similar as the SCI described in Fig. 3. Fig. 4 may be an example showing SL resource allocation being performed when assuming there are 4 candidate resource groups in the time axis resource.

[0074] The UE can monitor already determined SL communication resources and utilize them to directly perform resource allocation for SL communication.

[0075] Referring to FIG. 4, in the first situation (405), the first UE can first generate and transmit an SCI (410) in the l-th transmission (425). At this time, the SCI (410) may include resource allocation information that was allocated before the SCI was generated. The SCI (410) may include resource allocation information for the packet currently being transmitted. Additionally, the SCI (410) may include reservation information indicating that resources will be used in subsequent transmissions as well. When the SCI (410) is transmitted, a transmission block containing related data may also be transmitted together. For example, the transmission block may include a cooperative awareness message (CAM), a platoon awareness message (PAM), etc.

[0076] After transmitting the SCI (410), the first UE may perform resource allocation (420) for a subsequent transmission. At this time, the resource allocation (420) may be for the l+1th transmission (430), which is a subsequent transmission. The first UE may allocate resources by deciding to transmit the first packet (415) in the subsequent transmission. Here, the first packet (415) may include the SCI and transmission block of the subsequent transmission. Although not illustrated, when the first UE performs resource allocation, it may create a new SCI and transmit it to another UE containing information about the first packet (415).

[0077] In the second situation (455), the second UE may perform resource allocation (475) based on the SCI (460) received from the first UE in the l-th transmission (425). The resource allocation performed by the second UE may be a resource allocation for the l+1-th transmission (430), which is a subsequent transmission. The second UE may allocate resources by deciding to transmit the second packet (465) in the subsequent transmission. Here, the second packet (465) may include the SCI and transmission block of the subsequent transmission. At this time, the second UE may select one part from four candidate resource groups (470a to 470d).

[0078] However, since the SCI (460) received by the second UE is the SCI (410) transmitted by the first UE before the resource allocation for subsequent transmission was performed, the second UE may not receive information regarding the resource allocation for subsequent transmission determined by the first UE thereafter. Alternatively, the first UE may have transmitted an SCI containing information regarding the resource allocation for subsequent transmission, but the resource allocation for subsequent transmission was performed before that, or the transmission of the SCI may not have been performed depending on the location. In one embodiment, the second UE may be able to identify from the SCI (460) that resources are reserved for subsequent transmission, but may not be able to identify exactly which subframe of which frequency band.

[0079] In this case, the second UE may assign the second packet (465) to the second point (470b) among the candidate resource groups (470a to 470d). In this case, a collision may occur between the first packet (415) assigned by the first UE for subsequent transmission and the second packet (465) assigned by the second UE at the same resource.

[0080] As such, in SL communication, resource scheduling among UEs is not performed by a centralized base station. Therefore, if scheduling among UEs is performed based on conventional SCI, packet collisions may occur because the scheduling for subsequent transmissions among UEs is not unified due to the appearance of a new UE, resource allocation timing, or SCI transmission timing, or if an SCI is not transmitted to other UEs, or if an SCI is received but an additional SCI for a subsequent transmission is not received. This can lead to a degradation of communication quality in V2X and SL communication.

[0081] Accordingly, Figure 5 and below specifically describe a method of transmitting by including information about the resources allocated for subsequent transmission in the existing SCI.

[0082]

[0083] FIG. 5 may show a new format structure of SCI according to one embodiment of the present disclosure.

[0084] The SCI (500) of FIG. 5 may include a priority field (510), a resource reservation interval field (520), a frequency resource location field (530), a type gap field (540), a modulation coding scheme field (550), and a retransmission index field (560), as described in FIG. 3, and the functions and field sizes may be the same. The SCI (500) may be identical to the structure and form of the SCI specified in current communication standard protocols such as 3GPP.

[0085] The SCI (500) of FIG. 5 is a concept that extends the reservation field of the existing SCI and may include two additional fields. The SCI (500) may include a subsequent transmission frequency resource location field (575) and a subsequent transmission subframe index field (580) in the extended reservation field (570).

[0086] The subsequent transmission frequency resource location field (575) and the subsequent transmission subframe index field (580) can be included in the SCI when the UE selects a new resource.

[0087] The subsequent transmission frequency resource location field (575) may have a size of 4 bits and may contain information about the frequency resource to be occupied by the subsequent SCI or transmission block (TB) (or packet). The subsequent transmission frequency resource location field (575) may be calculated in the same or similar manner as the frequency resource location field (530).

[0088] The subsequent transmission subframe index field (580) may have a range of 7 bits and may be a value representing the difference between the subframe information of the current transmission SCI or transmission block and the subframe information of the subsequent transmission SCI or transmission block. For example, the subframe (t) of the lth transmission of the transmission block l ) and the l+1th transmitted subframe (t l+1 In ), the subsequent transmission subframe index field (580) is (t l+1 - t l The value of ), that is, a value between 0 and 127, can be encoded and included. Conversely, if the value of the subsequent transmission subframe index field (580) is η, then the subsequent transmission is (t l +(η+1)) can be transmitted in a subframe.

[0089] If the subsequent transmission frequency resource location field (575) and the subsequent transmission subframe index field (580) are empty, it may indicate that the same resource is used for subsequent transmission.

[0090]

[0091] FIG. 6 is a diagram illustrating a scenario in which resource allocation is performed based on a modified SCI according to one embodiment of the present disclosure to avoid packet collisions.

[0092] The SCI transmitted in Fig. 6 may be the same or similar as the SCI described in Fig. 5. Fig. 6 may be an example showing SL resource allocation being performed when assuming there are 4 candidate resource groups in the time axis resource.

[0093] Referring to FIG. 6, in the first situation (605), the first UE can perform resource allocation (620) by considering the first packet (615) to be transmitted in the subsequent transmission, the l+1th transmission (630), during the l-th transmission (625). When the first UE performs resource allocation, it can generate an SCI (610) and transmit it to another UE containing information about the first packet (615). At this time, the SCI (610) may include information on the location of the subsequent transmission frequency resource and information on the subsequent transmission subframe index. That is, the first UE can transmit the SCI by including frequency information and a subframe index regarding the resource to be used by the first packet (615) to be transmitted in the subsequent transmission, the l+1th transmission (630). When the SCI (610) is transmitted, a transmission block containing related data may also be transmitted together. In addition, the first packet (615) may include the SCI and transmission block of the subsequent transmission.

[0094] In the second situation (655), the second UE can receive the SCI (660) transmitted from the first UE in the l-th transmission (625) as in the first situation (605). Based on the received SCI (660), the second UE can allocate a second packet (665) for the l+1-th transmission (630), which is a subsequent transmission. At this time, one part of four candidate resource groups (670a to 670d) can be selected. However, when the second UE performs resource allocation (675) for packet transmission during the subsequent transmission (630), it can identify the subsequent transmission frequency resource location information and subsequent transmission subframe index information included in the SCI received from the first UE. Based on the identified subsequent transmission frequency resource location information and subsequent transmission subframe index information, the second UE can perform resource allocation for packet transmission by excluding resources where the packet will collide during the subsequent transmission (630). For example, the second UE can perform resource allocation on the remaining resources among the resources (670a to 670d) based on the received SCI, excluding the resource (670b) reserved by the first UE during subsequent transmission (630). For example, the second UE can allocate the second packet (665) to a resource (670c) other than the reserved resource (670b) based on resource information for subsequent transmission.

[0095]

[0096] FIG. 7 illustrates a method for allocating resources based on SCI and RSSI according to one embodiment of the present disclosure.

[0097] The SCI used in Fig. 7 may be the same or similar as the SCI described in Figs. 5 and 6.

[0098] In sensing-based semi-persistent scheduling (SB-SPS), resource information from surrounding vehicles can be monitored using SCI, and communication quality can be improved based on this. However, changes in the received signal strength indicator (RSSI) of the sensing matrix caused by hidden vehicles or exposed vehicles cannot be detected.

[0099] Since SB-SPS performs resource allocation based on the detected RSSI of the sensing window, it can be confirmed that there is a correlation between the RSSI of the sensing window and the signal-to-interference plus noise ratio (SINR) of transmitted / received packets. Based on this relationship, communication quality can be improved by estimating changes in RSSI values ​​caused by hidden / exposed vehicles using a new SCI.

[0100] In Fig. 7, the detected RSSI can be represented as a sensing matrix, and the prior RSSI can be represented as a prior sensing matrix.

[0101] The pre-sensing matrix estimator (750) is intended to respond to unexpected interference caused by the transmission of a hidden vehicle (715) or an exposed vehicle (720) in the sensing matrix.

[0102] The first UE (705) can periodically broadcast a CAM. Here, the CAM may include an SCI. Adjacent UEs (710, 715, 720) can decode the received CAM to identify location information and resource information for subsequent transmissions. Thus, the first UE (705) and adjacent UEs (710, 715, 720) can identify the location and resource information of adjacent vehicles based on the CAM.

[0103] The first UE (705) can utilize a pre-sensing matrix estimator (750) based on identified location information and resource information. In one embodiment, the pre-sensing matrix estimator (750) can be trained to be robust against the influence of channel noise using a deep learning-based model.

[0104] The first UE (705) can collect interference data by considering the distance to existing UEs and the number of existing UEs through a sensing matrix estimator. In addition, it can collect hidden interference data by considering the distance to hidden UEs and the number of hidden UEs. In addition, it can collect exposed interference data by considering the distance to exposed UEs and the number of exposed UEs.

[0105] In a conventional sensing matrix (755), RSSI information can be displayed based on the distance and number of existing UEs.

[0106] In the pre-sensing matrix (760), RSSI information can be represented by considering the distance and number of hidden UEs and the distance and number of exposed UEs based on the distance and number of existing UEs.

[0107] The first UE (705) can perform a preliminary RSSI estimation based on resource information for subsequent transmissions in a conventional sensing matrix (755), and can generate a preliminary sensing matrix (760) by applying hidden interference (730) and exposed interference (735).

[0108] The first UE (705) can perform distributed resource allocation (780) using the generated pre-sensing matrix (760).

[0109]

[0110] FIG. 8 is a flowchart illustrating a process in which a UE performs resource allocation by avoiding packet collisions according to one embodiment of the present disclosure.

[0111] Figure 8 may be a process illustrating how a UE performs resource allocation using the SCI described in Figures 5 to 7.

[0112] Here, the UE can represent various terminals described in FIG. 1 (e.g., RSU (105), vehicle (110), pedestrian (120).

[0113] In step S805, the UE can prepare for packet transmission.

[0114] In step S810, the UE can determine the current reselection counter (RC) by decrementing it by 1.

[0115] In step S815, the UE can determine whether the value of RC has become 0.

[0116] In step S820, the UE can decide whether to retain the resource if the value of RC is 0.

[0117] In step S845, if the value of RC in step S815 did not become 0, or if it was decided to retain the resource in step S820, the UE can transmit the prepared packet based on the resource.

[0118] In step S850, the UE can reset the value of RC to a new value.

[0119] In step S825, if the UE decides not to retain the resources in step S820, it may decide to perform a new resource allocation process. The UE may perform the new resource allocation and generate an SCI based on that resource allocation.

[0120] In step S830, the UE can include resource information for subsequent transmissions in the SCI based on newly allocated resources.

[0121] In step S835, the UE can transmit the SCI and the prepared packet to another UE.

[0122] In step S840, the UE can reset the value of RC to a new value.

[0123]

[0124] FIG. 9 is a flowchart illustrating a process in which a UE performs resource allocation based on SCI according to one embodiment of the present disclosure.

[0125] The SCI in FIG. 9 may be the same or similar as the SCI described in FIG. 5 to 8. Here, the UE may represent a vehicle operating a CACC service. The UE in FIG. 9 may represent a UE that has received the SCI generated by the UE in FIG. 8.

[0126] In step S905, the UE can set a selection window.

[0127] In step S910, the UE can monitor the sensing window.

[0128] In step S915, the UE sets the signal power threshold (P th You can set ).

[0129] In step S920, the UE can initialize L1, the available resource, to include the entire resource.

[0130] In step S925, the UE can decode the SCI of another UE that has been received. The UE can identify whether the decoded SCI contains resource information for a subsequent transmission (e.g., information contained in the subsequent transmission frequency resource location field (575) and the subsequent transmission subframe index field (580) of FIG. 5).

[0131] In step S930, if the SCI contains resource information for subsequent transfers, the UE can exclude resources reserved for subsequent transfers from the entire resource L1.

[0132] If the SCI does not contain resource information for a subsequent transmission in step S925, or after proceeding to step S930, in step S935, the UE may exclude candidate single sub-frame resources (CSRs) from L1 where the reference signal received power (RSRP) is greater than the signal power threshold.

[0133] In step S940, the UE can check whether L1 is greater than 20% of the initial value of L1.

[0134] If the value of L1 is less than 20% of the initial value of L1, in step S945, the magnitude of the signal power threshold can be increased by 3dB (decibels) and step S935 can be performed again.

[0135] If the value of L1 is greater than 20% of the initial value of L1, in step S950, the UE can select a resource from the 20% of candidate resources that include the lowest average RSSI.

[0136]

[0137] FIG. 10 is a block diagram of a UE according to one embodiment of the present disclosure.

[0138] Referring to FIG. 10, the UE (1000) may include a transceiver (1020), memory (1030), and a processor (1010).

[0139] The transceiver (1020) may be a communication modem that is electrically and communically connected to other electronic devices to enable mutual communication. In particular, the transceiver (1020) may receive a PSCCH, PSSCH signal or data signal and transmit it to a processor (1010), and the processor (1010) may process the received signal and store the included information in a memory (1030).

[0140] The memory (1030) is configured to store various information and program instructions for the operation of the UE (1000), and may be a storage device such as a hard disk or a solid state drive (SSD). In particular, the memory (1030) can store information included in a signal received from a transceiver (1020) under the control of the processor (1010). Additionally, the memory (1030) can store program instructions that can be executed by the processor (1010).

[0141] The processor (1010) is composed of at least one processor and can perform resource allocation using data and program instructions stored in memory (1030). The processor (1010) can control and utilize the terminals and resource allocation method, SCI generation method, SL communication method, etc. described in FIGS. 1 to 9.

[0142]

[0143] FIG. 11 is a flowchart illustrating a method for performing SL communication in a UE according to one embodiment of the present disclosure.

[0144] With reference to FIG. 11 below, the method for performing SL communication of the UE described in FIGs. 1 to 9 will be summarized and explained. Each operation is not an operation that must be necessarily included in the series of operations, and only some of them may be configured and operated depending on the situation.

[0145] In step S1110, the first UE (e.g., the first UE (110) of FIGS. 1 and FIGS. 2) can perform resource allocation for side link communication.

[0146] In step S1120, the first UE can generate side link control information (SCI) (e.g., SCI (500) of FIG. 5) based on the allocated resources.

[0147] In one embodiment, the SCI may include frequency information of a resource allocated to a packet to be subsequently transmitted (e.g., the subsequent transmission frequency resource location field (575) of FIG. 5) and subframe index information of a resource allocated to a packet to be subsequently transmitted (e.g., the subsequent transmission subframe index field (580) of FIG. 5).

[0148] In one embodiment, the SCI may further include priority information, resource reservation interval information, frequency resource location information of the currently transmitted packet, time gap information, modulation coding scheme information, and retransmission index information (e.g., priority field (510), resource reservation interval field (520), frequency resource location field (530), time gap field (540), modulation coding scheme field (550), retransmission index field (560) of FIG. 5).

[0149] In one embodiment, the frequency information of the resource allocated to the subsequent packet to be transmitted can be expressed in the same way as the frequency resource location information of the currently transmitted packet.

[0150] In step S1130, the first UE can transmit a PSCCH containing the SCI to an adjacent second UE (e.g., the second UE (120) of FIG. 1 and FIG. 2).

[0151] In one embodiment, the subframe index information of the resource allocated to the subsequent packet to be transmitted may include information regarding the difference between the subframe of the currently transmitted packet and the subframe of the subsequent packet to be transmitted.

[0152] In one embodiment, when the currently transmitted packet is transmitted at the nth, the subsequent packet to be transmitted may be transmitted at the n+1th.

[0153] In one embodiment, the SCI may be configured with a size of 32 bits, frequency information of the resource allocated to the subsequent packet to be transmitted may be configured with a size of 4 bits, and subframe information of the resource allocated to the subsequent packet to be transmitted may be configured with a size of 7 bits.

[0154] In one embodiment, when the resource allocated to the packet to be subsequently transmitted and the resource allocated to the packet currently being transmitted are the same, the values ​​of the frequency information of the resource allocated to the packet to be subsequently transmitted and the subframe index information of the resource allocated to the packet to be subsequently transmitted may be determined to be 0.

[0155]

[0156] FIG. 12 is a flowchart illustrating a method for performing SL communication based on SCI in a UE according to one embodiment of the present disclosure.

[0157] With reference to FIG. 12 below, a method for performing SL communication based on the SCI of the UE described in FIGs. 1 to 9 is summarized and explained. Each operation is not an operation that must be necessarily included in the series of operations, and only some of them may be configured and operated depending on the situation.

[0158] In step S1210, the second UE (e.g., the second UE (120) of FIG. 1 and FIG. 2) may receive a PSCCH containing SCI from an adjacent first UE.

[0159] In step S1220, the second UE can perform resource allocation for performing side link communication based on the SCI.

[0160] In one embodiment, the SCI may include frequency information of a resource allocated to a packet to be subsequently transmitted and subframe index information of a resource allocated to a packet to be subsequently transmitted.

[0161] In one embodiment, the second UE can decode the SCI and identify frequency information of the resource allocated to the subsequent packet to be transmitted and subframe index information of the resource allocated to the subsequent packet to be transmitted from the decoded SCI.

[0162] In one embodiment, the second UE may exclude resources already reserved among the resources available for the side link communication based on frequency information of the resources allocated to the identified subsequent packet to be transmitted and subframe index information of the resources allocated to the subsequent packet to be transmitted.

[0163] In one embodiment, the second UE can perform resource allocation by selecting resources among the resources from which the reserved resources are excluded that have an RSSI value lower than a predetermined value.

[0164]

[0165] Although the technical concept of the present disclosure has been described in detail with reference to various embodiments, the technical concept of the present disclosure is not limited to the above embodiments, and various modifications and changes can be made by those skilled in the art within the scope of the technical concept of the present disclosure.

Claims

1. A method performed by first user equipment (UE), A step of performing resource allocation for sidelink (SL) communication; A step of generating sidelink control information (SCI) based on the above-mentioned allocated resources; The method includes the step of transmitting a PSCCH (physical sidelink control channel) containing the SCI to an adjacent second UE, and The above SCI is a method comprising frequency information of a resource allocated to a packet to be subsequently transmitted and subframe index information of a resource allocated to a packet to be subsequently transmitted.

2. In Paragraph 1, The above SCI further includes priority information, resource reservation interval information, frequency resource location information of the currently transmitted packet, time gap information, modulation coding scheme information, and retransmission index information.

3. In Paragraph 2, A method in which the frequency information of a resource allocated to the packet to be subsequently transmitted is expressed in the same manner as the frequency resource location information of the packet currently being transmitted.

4. In Paragraph 1, A method in which the subframe index information of the resource allocated to the subsequent packet to be transmitted includes information about the difference between the subframe of the packet currently being transmitted and the subframe of the packet to be transmitted subsequently.

5. In Paragraph 2, A method in which, when the currently transmitted packet is transmitted at the nth, the subsequent packet to be transmitted is transmitted at the n+1th.

6. In Paragraph 1, The above SCI is composed of a size of 32 bits, and The frequency information of the resource allocated to the above-mentioned subsequent packet to be transmitted is composed of a size of 4 bits, and A method in which subframe information of a resource allocated to the above-mentioned subsequent packet to be transmitted is configured with a size of 7 bits.

7. In Paragraph 1, When the resources allocated to the packet to be subsequently transmitted are the same as the resources allocated to the packet currently being transmitted. A method in which the values ​​of frequency information of a resource allocated to a packet to be subsequently transmitted and subframe index information of a resource allocated to a packet to be subsequently transmitted are determined to be 0.

8. In a method performed by a second user equipment (UE), A step of receiving a PSCCH (physical sidelink control channel) containing an SCI from an adjacent first UE; It includes the step of performing resource allocation for performing side link communication based on the above SCI, and The above SCI is a method comprising frequency information of a resource allocated to a packet to be subsequently transmitted and subframe index information of a resource allocated to a packet to be subsequently transmitted.

9. In Paragraph 8, The step of performing the above resource allocation is: Step of decoding the above SCI; A method comprising the step of identifying frequency information of a resource allocated to a subsequent packet to be transmitted and subframe index information of a resource allocated to a subsequent packet to be transmitted from the decoded SCI.

10. In Paragraph 9, The step of performing the above resource allocation is: A method comprising the step of excluding already reserved resources among the resources available for the side link communication based on frequency information of the resources allocated to the identified subsequent packet to be transmitted and subframe index information of the resources allocated to the subsequent packet to be transmitted.

11. In Paragraph 10, The step of performing the above resource allocation is: A method comprising the step of performing resource allocation by selecting resources among the resources excluded from the above-mentioned reserved resources whose RSSI value is lower than a predetermined value.

12. In Paragraph 8, A method in which the frequency information of a resource allocated to the packet to be subsequently transmitted is expressed in the same way as the frequency resource location information of the packet currently being transmitted.

13. In Paragraph 8, A method in which the subframe index information of the resource allocated to the subsequent packet to be transmitted includes information about the difference between the subframe of the packet currently being transmitted and the subframe of the packet to be transmitted subsequently.

14. In the first user equipment (UE), Memory; Transmitter / receiver; and It includes a processor connected to the above-mentioned transceiver and the above-mentioned memory, and The above processor is: Perform resource allocation for sidelink (SL) communication, and Based on the above allocated resources, sidelink control information (SCI) is generated, and It is configured to transmit a PSCCH (physical sidelink control channel) containing the above SCI to an adjacent second UE, and The above SCI is a first UE including frequency information of a resource allocated to a packet to be subsequently transmitted and subframe index information of a resource allocated to a packet to be subsequently transmitted.

15. In the second user equipment (user equipment: UE), Memory; Transmitter / receiver; and It includes a processor connected to the above-mentioned transceiver and the above-mentioned memory, and The above processor is: Receive a PSCCH (physical sidelink control channel) containing SCI from an adjacent first UE, and It is configured to perform resource allocation for performing side link communication based on the above SCI, and The above SCI is a second UE including frequency information of a resource allocated to a packet to be subsequently transmitted and subframe index information of a resource allocated to a packet to be subsequently transmitted.

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