Method and apparatus for controlling transmission power of ue in wireless communication system

Abstract

The disclosure relates to a communication scheme and a system thereof, which combines IoT technology and a 5G communication system for supporting a higher data transmission rate than a 4G system. The disclosure can be applied to intelligent services (e.g., smart homes, smart buildings, smart cities, smart cars or connected cars, health care, digital education, retail businesses, security and safety-related services, etc.) based on 5G communication technology and IoT-related technology. According to an embodiment of the disclosure, a method of a sidelink receiving user equipment (UE) in a communication system is provided. The method includes receiving, from a base station, configuration information associated with power control for transmission of a physical sidelink feedback channel (PSFCH), receiving a plurality of physical sidelink shared channels (PSSCHs) scheduled based on a plurality of sidelink control information (SCI), identifying at least one first PSFCH based on a number of PSFCHs scheduled in response to reception of the plurality of PSSCHs and a maximum number of PSFCHs that the first UE is capable of transmitting, identifying at least one second PSFCH in an order of high priority indicated by the plurality of SCI in a case where a total transmission power of the at least one first PSFCH is greater than a maximum transmission power of the first UE, wherein the number of the at least one second PSFCH is the maximum number of PSFCHs that can make a sum of transmission powers less than or equal to the maximum transmission power, identifying a first transmission power of each of the at least one second PSFCH based on the number of the at least one second PSFCH, and transmitting the at least one second PSFCH based on the first transmission power.

Description

TECHNICAL FIELD

[0001] The disclosure relates to a method and apparatus for controlling transmission power of a user equipment (UE) in a wireless communication system, and more particularly, to a method and apparatus for setting transmission power of a sidelink synchronization channel and a sidelink feedback channel by a UE. BACKGROUND

[0002] To meet increasing demand for wireless data traffic since the deployment of 4G communication systems, efforts have been made to develop an improved 5G or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a 'Beyond 4G Network' or a '5G Network'. The 5G communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 60GHz bands, so as to accomplish higher data rates. To mitigate a propagation loss of the radio waves and increase a transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed for use in the 5G communication system. In addition, in the 5G communication system, development for system network improvement is under way based on advanced small cells, cloud radio access networks (RANs), ultra-dense networks, a technology for coordination between cells, a cooperative multi-cell transmission technique, a coordination-based multi-point (CoMP) transmission / reception, a network-based data compression, a network influence on McT, a wireless backhaul, a moving network, a cooperative communication, an interference mitigation, and the like. In the 5G system, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), and filter bank multi carrier (FBMC), a non-orthogonal multiple access (NOMA), and a sparse code multiple access (SCMA) as an advanced access technology have been developed.

[0003] The Internet, which is a human centered connectivity network where humans generate and consume information, is now evolving to the Internet of Things (IoT) where distributed entities, such as things, exchange and process information without human intervention. The Internet of Everything (IoE), which is a combination of the IoT technology and the Big Data processing technology through connection with a cloud server, has emerged as a new paradigm for the IoT. As technology elements, such as "sensing technology", "wired / wireless communication and network infrastructure", "service interface technology", and "security technology" have been demanded for IoT implementation, a sensor network, a Machine-to-Machine (M2M) communication, Machine Type Communication (MTC), and the like have been researched. Such an IoT environment can provide intelligent Internet technology services that create a new value through collection and analysis of data generated from connected things. The IoT can be applied to a variety of fields including smart home, smart building, smart city, smart car or connected cars, smart grid, health care, smart appliances, and advanced medical services, through the combination and interworking of existing information technology (IT) and various industrial applications.

[0004] In line with this, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as a sensor network, Machine Type Communication (MTC), and Machine-to-Machine (M2M) communication can be implemented by beamforming, MIMO, and array antennas. Application of a cellular network to a M2M network where a plurality of devices transmits / receives data to / from a single device can also be considered as an example of convergence of the 5G technology with the IoT technology.

[0005] As described above, as wireless communication systems evolve, various services can be provided, and thus schemes for efficiently providing the services are required. SUMMARY

[0006] TECHNICAL PROBLEM

[0007] The disclosure provides a method and apparatus for efficiently controlling transmission power of a UE in a wireless communication system.

[0008] SOLUTION TO PROBLEM

[0009] According to an aspect of the disclosure, a method of a sidelink receiving user equipment (RX UE) in a communication system is provided. The method can include receiving, from a base station, configuration information associated with power control for transmission of a physical sidelink feedback channel (PSFCH), receiving a plurality of physical sidelink shared channels (PSSCHs) scheduled based on a plurality of sidelink control information (SCIs), identifying at least one first PSFCH based on a number of the PSFCHs scheduled in response to reception of the plurality of PSSCHs and a maximum number of the PSFCHs that the first UE is capable of transmitting, identifying at least one second PSFCH in an order of high priority indicated by the plurality of SCIs in a case that a total transmission power of the at least one first PSFCH is greater than a maximum transmission power of the first UE, wherein a number of the at least one second PSFCH is a maximum number of the PSFCHs that can make a sum of transmission power less than or equal to the maximum transmission power, identifying a first transmission power of each of the at least one second PSFCH based on the number of the at least one second PSFCH, and transmitting the at least one second PSFCH based on the first transmission power.

[0010] According to an aspect of the disclosure, a sidelink RX UE in a communication system is provided. The RX UE can include a transceiver; and a controller configured to: control the transceiver to receive, from a base station, configuration information associated with power control for transmission of a physical sidelink feedback channel (PSFCH); control the transceiver to receive a plurality of physical sidelink shared channels (PSSCHs) scheduled based on a plurality of sidelink control information (SCI); identify at least one first PSFCH based on a number of PSFCHs scheduled in response to reception of the plurality of PSSCHs and a maximum number of PSFCHs that the first UE is capable of transmitting; identify at least one second PSFCH in an order of high priority indicated by the plurality of SCI in a case where a total transmission power of the at least one first PSFCH is greater than a maximum transmission power of the first UE, wherein the number of the at least one second PSFCH is a maximum number of PSFCHs that can make a sum of transmission powers less than or equal to the maximum transmission power; identify a first transmission power of each of the at least one second PSFCH based on the number of the at least one second PSFCH; and control the transceiver to transmit the at least one second PSFCH based on the first transmission power.

[0011] Advantages of the Invention

[0012] According to the disclosure, a user equipment (UE) can effectively provide a service by controlling a transmission power of a sidelink synchronization channel and a sidelink feedback channel in a wireless communication system.

[0013] Effects obtainable according to the disclosure are not limited to the above-mentioned effects and other effects not mentioned above will be clearly understood by those skilled in the art from the description provided below. BRIEF DESCRIPTION OF DRAWINGS

[0014] The above and other aspects, features and advantages of the disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0015] Figure 1 is a diagram illustrating a sidelink system according to an embodiment of the disclosure;

[0016] Figure 2 is a diagram illustrating a sidelink communication method performed via a sidelink according to an embodiment of the disclosure;

[0017] Figure 3 is a diagram illustrating a protocol of a sidelink user equipment (UE) according to an embodiment of the disclosure;

[0018] Figure 4 is a diagram illustrating a sidelink unicast communication procedure according to an embodiment of the disclosure;

[0019] Figure 5FIG. 1 is a diagram illustrating a sidelink unicast communication procedure according to an embodiment of the disclosure;

[0020] Figure 6 FIG. 2 is a diagram illustrating a structure of a sidelink synchronization channel according to an embodiment of the disclosure;

[0021] Figure 7 FIG. 3 is a diagram illustrating a structure of a sidelink control channel and a data channel according to an embodiment of the disclosure;

[0022] Figure 8 FIG. 4 is a diagram illustrating an example of a procedure of transmitting a sidelink feedback channel by a V2X UE in a wireless communication system according to various embodiments of the disclosure;

[0023] Figure 9 FIG. 5 is a diagram illustrating a structure of a sidelink feedback channel according to an embodiment of the disclosure;

[0024] Figure 10 FIG. 6 is a diagram illustrating an example of controlling sidelink transmission power according to an embodiment of the disclosure;

[0025] Figure 11 FIG. 7 is a diagram illustrating interference caused by a frequency block transmitted by a sidelink UE to adjacent frequency blocks according to an embodiment of the disclosure;

[0026] Figure 12 FIG. 8 is a diagram illustrating interference caused by a frequency block transmitted by a sidelink UE to adjacent frequency blocks according to an embodiment of the disclosure;

[0027] Figure 13 FIG. 9 is a diagram illustrating a method of controlling transmission power of a sidelink synchronization channel according to an embodiment of the disclosure;

[0028] Figure 14 FIG. 10 is a diagram illustrating an example of allocating a time axis resource for a sidelink feedback channel according to an embodiment of the disclosure;

[0029] Figure 15 FIG. 11 is a flowchart illustrating an example of a transmission power determination method when a single sidelink reception UE transmits multiple sidelink feedback channels according to an embodiment of the disclosure;

[0030] Figure 16 FIG. 12 is a block diagram illustrating a structure of a transmission (TX) UE according to an embodiment of the disclosure;

[0031] Figure 17 FIG. 13 is a block diagram illustrating a structure of a reception (RX) UE according to an embodiment of the disclosure;

[0032] Figure 18 FIG. 14 is a flowchart illustrating an example of a transmission power determination method when a single sidelink RX UE transmits multiple sidelink feedback channels according to an embodiment of the disclosure; and

[0033] Figure 19 FIG. 7 is a flowchart illustrating an example of a transmission power determination method when a single sidelink RX UE transmits a plurality of sidelink feedback channels according to an embodiment of the disclosure. DETAILED DESCRIPTION

[0034] Hereinafter, embodiments of the disclosure will be described in detail with reference to the accompanying drawings.

[0035] In describing embodiments of the disclosure, a description related to technical contents well known in the art and having no direct connection with the disclosure will be omitted. Such omission of unnecessary description is intended to prevent obscuring the main idea of the disclosure and to more clearly convey the main idea.

[0036] For the same reason, in the drawings, some elements can be enlarged, omitted, or schematically shown. Also, the size of each element does not completely reflect the actual size. In the drawings, the same or corresponding elements have the same reference numerals.

[0037] The advantages and features of the disclosure and the means for achieving them will become apparent by referring to the embodiments described below in detail in connection with the accompanying drawings. However, the disclosure is not limited to the embodiments set forth below, but can be implemented in various different forms. The embodiments are provided only to completely disclose the disclosure and to inform those skilled in the art of the scope of the disclosure, and the disclosure is limited only by the scope of the claims. Throughout the specification, the same or similar reference numerals denote the same or similar elements.

[0038] Here, it should be understood that each block of the flowchart illustrations and combinations of blocks in the flowchart illustrations can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart block or blocks. These computer program instructions can also be stored in a computer-usable or computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-usable or computer-readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks. The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer- implemented process such that the instructions executed on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks.

[0039] Also, each block in the flowchart illustrations can represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that in some alternative implementations, the functions noted in the blocks can occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks can sometimes be executed in the reverse order, depending on the functionality involved.

[0040] As used herein, "unit" refers to a software element or hardware element that performs a predetermined function, such as a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC). However, "unit" does not always have the meaning limited to software or hardware. The "unit" can be constructed as a storage medium that stores one or more processors, or as a portion thereof. Thus, the "unit" includes, for example, a software element, an object-oriented software element, a class element or a task element, a process, a function, a property, a procedure, a subroutine, a program code segment, a driver, firmware, a microcode, a circuit, a data, a database, a data structure, a table, an array, and a parameter. Elements and functions provided by the "unit" can be either combined into a smaller number of elements or "units", or divided into a larger number of elements or "units". The element and "unit" can also be implemented as one or more CPUs in a reconfigurable device or a secure multimedia card. Further, the "unit" in the embodiments can include one or more processors.

[0041] A detailed description of embodiments of the disclosure is provided mainly with reference to a radio access network New RAN (NR) and a packet core (which is a core network (5G system, 5G core network, or NG core: next generation core)) in the 5G mobile communication standard specified by 3GPP, which is a standard organization, for a mobile communication standard. However, the subject matter of the disclosure is slightly modified and can be applied to other communication systems having a similar technical background without departing from the scope of the disclosure

[0042] In the disclosure, a sidelink UE can be referred to as an NR V2X UE or an LTE V2X UE. In the disclosure, a sidelink UE can be referred to as a UE supporting device-to-device (D2D) communication. Further, the V2X UE in the disclosure can be a vehicle supporting vehicle-to-vehicle (V2V) communication, a vehicle or a hand-held device (i.e., a smartphone) supporting vehicle-to-pedestrian (V2P) communication, a vehicle supporting vehicle-to-network (V2N) communication, or a vehicle supporting vehicle-to-infrastructure (V2I) communication. Further, the user equipment (UE) in the disclosure can be a road side unit (RSU) equipped with a UE function, an RSU equipped with a base station function, or an RSU equipped with a partial base station function and a partial UE function.

[0043] Further, a sidelink transmission (TX) UE in the disclosure is a UE that transmits sidelink data and control information or a UE that receives sidelink feedback information. Further, a sidelink reception (RX) UE is a UE that receives sidelink data and control information or a UE that transmits sidelink feedback information.

[0044] Embodiments of the disclosure provide a method and apparatus for controlling transmission power of a sidelink synchronization channel in order to improve a coverage area of a sidelink system and minimize interference caused by the sidelink system to a cellular system.

[0045] Further, embodiments of the disclosure provide a method and apparatus for controlling transmission power of a sidelink feedback channel in order to improve reliability of a sidelink system and support a high transmission rate.

[0046] Further, embodiments of the disclosure provide a method and apparatus for efficiently providing a service in a mobile communication system.

[0047] According to embodiments of the disclosure, transmission power parameters of a sidelink synchronization channel and a sidelink feedback channel can be adjusted based on a quality of a channel between a base station and a sidelink UE. Through the above description, in a sidelink system such as vehicle communication, device-to-device (D2D) communication, etc., a coverage area of a sidelink synchronization signal can be improved. Further, reliability and a transmission rate of sidelink feedback information can be improved. Further, an amount of interference caused by a sidelink system to a cellular system can be reduced. Accordingly, embodiments of the disclosure can support more efficient sidelink communication. Further, a service can be efficiently provided in a mobile communication system.

[0048] Figure 1 (a) to Figure 1 (d) is a diagram illustrating a sidelink system according to embodiments of the disclosure.

[0049] Figure 1 (a) is a diagram illustrating an example of a case in which all sidelink UEs (UE1 and UE2) are located in a coverage area of a base station.

[0050] Each sidelink UE can receive data and control information from the base station in a downlink (DL) or can transmit data and control information to the base station in an uplink (UL). In this case, the data and control information can be data and control information for sidelink communication. Alternatively, the data and control information can be data and control information for normal cellular communication. Further, each sidelink UE can transmit / receive data and control information for sidelink communication in a sidelink (SL).

[0051] Figure 1(b) is a diagram showing an example of a case where UE-1 among sidelink UEs is located within a coverage area of a base station, and UE-2 is located outside the coverage area of the base station. Figure 1 An example of (b) can be regarded as an example associated with a partial coverage area.

[0052] UE-1 located within the coverage area of the base station can receive data and control information from the base station in a downlink (DL), or can transmit data and control information to the base station in an uplink (UL).

[0053] UE-2 located outside the coverage area of the base station can not be able to receive data and control information from the base station in the downlink, and can not be able to transmit data and control information to the base station in the uplink.

[0054] UE2 can transmit / receive data and control information for sidelink communication in a sidelink with UE1.

[0055] Figure 1 (c) is a diagram showing an example of a case where all sidelink UEs are located outside the coverage area of the base station.

[0056] Therefore, UE1 and UE2 can not be able to receive data and control information from the base station in the downlink, and can not be able to transmit data and control information to the base station in the uplink.

[0057] UE1 and UE2 can transmit / receive data and control information for sidelink communication in a sidelink.

[0058] Figure 1 (d) is an example of a scenario where UEs located in different cells perform sidelink communication. Specifically, it is shown that a sidelink transmitting (TX) UE and a sidelink receiving (RX) UE are in an access state (RRC connected state) or in a state of camping on different base stations (RRC disconnected state, i.e., RRC idle state). In this case, UE1 can be a sidelink TX UE, and UE2 can be a sidelink RX UE. Alternatively, UE1 can be a sidelink RX UE, and UE2 can be a sidelink TX UE. UE1 can receive a sidelink dedicated system information block from a base station to which UE1 accesses (or camps), and UE2 can receive a sidelink dedicated SIB from another base station to which UE2 accesses (or camps). In this case, information associated with the sidelink dedicated SIB received by UE1 and information of the sidelink dedicated SIB received by UE2 can be different from each other. Therefore, it is necessary to unify these information in order to perform sidelink communication between UEs located in different cells.

[0059] Although, for the sake of description, Figure 1A sidelink system including two UEs (UE1 and UE2) is shown, but the present disclosure is not limited thereto. In addition, the uplink and downlink between the base station and the sidelink UE can be referred to as a Uu interface, and the sidelink between the sidelink UEs can be referred to as a PC5 interface. Accordingly, these terms can be used interchangeably in the present disclosure.

[0060] In the present disclosure, the UE can be a UE supporting device-to-device (D2D) communication, a vehicle supporting vehicle-to-vehicle (V2V) communication, a vehicle or a handheld device (i.e., a smartphone) supporting vehicle-to-pedestrian (V2P) communication, a vehicle supporting vehicle-to-network (V2N) communication, or a vehicle supporting vehicle-to-infrastructure (V2I) communication. In addition, the UE in the present disclosure can be a roadside unit (RSU) equipped with a UE function, an RSU equipped with a base station function, or an RSU equipped with a partial base station function and a partial UE function.

[0061] In addition, the base station in the present disclosure can be a base station supporting both sidelink communication and normal cellular communication, or can be a base station supporting only sidelink communication. In this case, the base station can be a 5G base station (gNB), a 4G base station (eNB), or a roadside unit (RSU). Accordingly, unless otherwise mentioned, the base station and the RSU can be used as the same concept and can be used interchangeably in the present disclosure.

[0062] Figure 2 (a) and Figure 2 (b) is a diagram illustrating a sidelink communication method performed via a sidelink according to an embodiment of the present disclosure.

[0063] According to Figure 2 (a), a transmitting (TX) UE and a receiving (RX) UE can perform one-to-one communication, which is referred to as unicast communication. For example, if UE-1 is a TX UE, UE-2 can be an RX UE. Alternatively, if UE-2 is a TX UE, UE-1 can be an RX UE.

[0064] According to Figure 2 (b), a TX UE and an RX UE can perform one-to-many communication, which can be referred to as groupcast or multicast.

[0065] Figure 2 (b) shows that UE1, UE2, and UE3 are grouped (Group A) and perform groupcast communication, and UE4, UE5, UE6, and UE7 are grouped (Group B) and perform groupcast communication. Each UE performs groupcast within a group to which the respective UE belongs, and communication between different groups can be performed via unicast, groupcast, or broadcast communication. Although Figure 2 (b) shows that there are two groups, but the present disclosure is not limited thereto.

[0066] Although not shown in Figure 2 , a sidelink UE can perform broadcast communication. The broadcast communication can be a case where all sidelink UEs receive data and control information transmitted from a sidelink TX UE via a sidelink. For example, in Figure 2 (b), if it is assumed that UE1 is a TX UE for broadcast, all UEs (UE2, UE3, UE4, UE5, UE6, and UE7) can receive data and control information transmitted from UE1.

[0067] Figure 3 is a diagram showing a protocol of a sidelink UE according to an embodiment of the disclosure.

[0068] Although not shown in Figure 3 , an application layer of UE-A and UE-B can perform service discovery. In this case, the service discovery can include discovery associated with a type of sidelink communication (unicast, groupcast, or broadcast) to be performed by each UE. Thus, it is assumed that UE-A and UE-B recognize that the UEs will perform unicast communication via a service discovery procedure performed in an application layer. The sidelink UEs can obtain information associated with a source identifier (ID) and a destination ID for sidelink communication via the service discovery procedure.

[0069] If the service discovery procedure is completed, a PC5 signaling protocol layer in Figure 3 can perform a direct link connection setup between UEs. In this case, the PC5 signaling protocol layer can exchange security configuration information for direct communication between the UEs.

[0070] If the direct link connection setup between the UEs is completed, a PC5 radio resource control (RRC) layer in Figure 3 can perform a PC5 RRC setup procedure between the UEs. In this case, information associated with capabilities of UE-A and UE-B can be exchanged, and access stratum (AS) layer parameter information for unicast communication can be exchanged. In this case, information associated with capabilities of the UEs negotiated via the PC5 RRC between the UEs can be a subset of information used in negotiation associated with capabilities of the base station and the UEs. For example, it is assumed that a sidelink UE is capable of reporting information A, B, C, and D associated with capabilities of the sidelink UE itself to the base station. In this case, the sidelink UE can perform negotiation associated with part of the information via the PC5 RRC.

[0071] If the PC5 RRC setup procedure is completed, UE-A and UE-B can perform unicast communication.

[0072] Although unicast communication has been described as an example in the above description, this example can be extended to multicast communication. For example, if Figure 3 If UE-A, UE-B, and UE-C, not mentioned above, perform multicast communication, then as described above, UE-A and UE-B perform service discovery, direct link establishment between UEs, and PC5 RRC establishment for unicast communication. Furthermore, UE-A and UE-C can also perform service discovery, direct link establishment between UEs, and PC5 RRC establishment for unicast communication. Finally, UE-B and UE-C can perform service discovery, direct link establishment between UEs, and PC5 RRC establishment for unicast communication. That is, the PC5 RRC establishment process for unicast communication is performed by each pair of TX UEs and RX UEs joining the multicast communication, rather than being performed separately for multicast communication.

[0073] Figure 4 This is a diagram illustrating a sidelink unicast communication process according to an embodiment of the present disclosure.

[0074] Specifically, Figure 4 It shows that it is based on what has already been shown Figure 2 A diagram illustrating the sidelink communication process of resource allocation mode 1 as described in [the original text]. Figure 4 In operation S410, the base station (e.g., eNB / gNB / RSU) uses system information to configure parameters for sidelink communication of TX UEs and RX UEs in the cell. For example, the base station (gNB) can configure information associated with resource pools that enable sidelink communication in its cell. In this case, the resource pool can be a transmit resource pool for sidelink transmission or a receive resource pool for sidelink reception. The base station can configure sidelink UEs using information associated with one or more resource pools. The base station can use the system information to perform configurations that enable unicast, multicast, and broadcast communication in different resource pools. For example, resource pool 1 can be used for unicast communication, resource pool 2 can be used for multicast communication, and resource pool 3 can be used for broadcast communication. As another example, the base station can perform configurations that enable unicast, multicast, and broadcast communication in the same resource pool. As another example, the base station can configure different resource pools depending on whether there are resources in the resource pool for a physical sidelink feedback channel (PSFCH) for transmitting sidelink feedback information. Specifically, resource pool 1 can be a pool where PSFCH resources exist, and resource pool 2 can be a pool where PSFCH resources do not exist. In this scenario, sidelink unicast and multicast data requiring mixed Automatic Repeat and Request (HARQ) feedback can use resource pool 1. Sidelink unicast, multicast, and broadcast data that do not require HARQ feedback can use resource pool 2.

[0075] The resource pool information configured by the base station can include at least one of the following information. The following information is only an example, and the present disclosure is not limited thereto.

[0076] 1. Information associated with time resources of a resource pool: Specifically, the information can include a slot index of a slot in which a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), and a physical sidelink feedback channel (PSFCH) are transmitted; or a slot index of a slot in which the PSCCH, the PSSCH, and the PSFCH are transmitted and an index of a symbol in the corresponding slot. In addition, the information can include a periodic interval of resources in which the PSCCH, the PSSCH, and the PSFCH are transmitted.

[0077] 2. Information associated with frequency resources of a resource pool: is information associated with a frequency axis in a resource pool in which the PSCCH, the PSSCH, and the PSSCH are transmitted. In particular, the information can include a resource block index of a resource block in the resource pool or an index of a subchannel including two or more resource blocks.

[0078] 3. Information associated with whether to operate sidelink HARQ-ACK can be included in the resource pool configuration information.

[0079] (1) In the case of operating sidelink HARQ-ACK, at least one of the following information can be included.

[0080] (1-1) Maximum number of retransmissions

[0081] (1-2) HARQ-ACK timing: refers to a time period from a time point at which a sidelink RX UE receives sidelink control information and data information from a sidelink TX UE to a time point at which the sidelink RX UE transmits HARQ-ACK / NACK information associated with the reception to the sidelink TX UE. In this case, the time unit can be a slot or one or more OFDM symbols.

[0082] (1-3) PSFCH format or HARQ feedback method: If two or more PSFCH formats are used, one PSFCH format can be used to transmit 1-bit or 2-bit HARQ-ACK / NACK information. Another PSFCH format can be used to transmit 3-bit or more HARQ-ACK / NACK information. If the above HARQ-ACK / NACK information is transmitted via PSFCH, each of ACK information and NACK information can be transmitted via PSFCH. In this case, if the sidelink RX UE successfully decodes the PSSCH transmitted from the sidelink TX UE, the sidelink RX UE can transmit ACK via PSFCH. If the decoding fails, the sidelink RX UE can transmit NACK via PSFCH. As another example, if the sidelink RX UE successfully decodes the PSSCH transmitted from the sidelink TX UE, the sidelink RX UE can not transmit ACK, and only when the decoding fails, the sidelink RX UE can transmit NACK via PSFCH. Unlike the above, if a single PSFCH format is used, information associated with the HARQ feedback method (whether each of ACK information and NACK information is to be transmitted via PSFCH, or whether only NACK information is transmitted via PSFCH) can be included.

[0083] (1-4) Time / frequency / code resource or resource set of PSFCH: The time resource can include a slot index or a symbol index associated with the transmission of the PSFCH and a periodic interval. The frequency resource can include a resource block (RB) or a start point and an end point of a subchannel including two or more contiguous blocks in which the PSFCH is transmitted (or a start point and a length of the frequency resource).

[0084] 4. Information associated with whether blind retransmission is used can be included in the resource pool configuration information.

[0085] Unlike the retransmission based on HARQ-ACK / NACK, the blind retransmission is a process in which the TX UE does not receive feedback information associated with ACK or NACK from the RX UE, but the TX UE repeatedly performs transmission. If the blind retransmission is used, the number of times of performing the blind retransmission can be included in the resource pool information. For example, if the number of blind retransmissions is set to 4, when the PSCCH / PSSCH is transmitted to the RX UE, the TX UE can always transmit the same information four times. In this case, a redundancy version (RV) value can be included in the sidelink control information (SCI) transmitted via the PSCCH.

[0086] 5. Information associated with a DMRS pattern that can be used in the PSSCH transmitted in the corresponding resource pool.

[0087] The DMRS pattern that can be used in the PSSCH can be different depending on the speed of the UE. For example, if the speed of the UE is high, the number of OFDM symbols for DMRS transmission on the time axis needs to be increased to improve the accuracy of channel estimation. In addition, if the speed of the UE is low, the accuracy of channel estimation can be guaranteed even if a small number of DMRS symbols is used. Therefore, the number of OFDM symbols for DMRS transmission on the time axis needs to be reduced to reduce DMRS overhead. Accordingly, the resource pool information can include information associated with a DMRS pattern that can be used in the corresponding resource pool. In this case, two or more DMRS patterns can be configured for a single resource pool, and the sidelink TX UE can select and use one of the configured DMRS patterns based on the speed of the UE itself. In addition, the sidelink TX UE can transmit information associated with the selected DMRS pattern to the sidelink RX UE using the SCI of the PSCCH. The sidelink RX UE can receive the information, can obtain the DMRS pattern information, can perform channel estimation associated with the PSSCH, and can undergo a demodulation and decoding process, thereby obtaining sidelink data information.

[0088] 6. Information indicating whether sidelink channel state information reference signal (CSI-RS) is used

[0089] (1) In the case where sidelink CSI-RS is used, at least one of the following information can be included.

[0090] (1-1) Start point of CSI-RS transmission: indicates a start point at which the sidelink TX UE starts to transmit the CSI-RS to the sidelink RX UE. The start point can be an index of a slot in which the CSI-RS is transmitted, an index of a symbol in which the CSI-RS is transmitted, or both the index of the slot and the index of the symbol in which the CSI-RS is transmitted.

[0091] (1-2) CSI reporting timing: a time period from a time point at which the sidelink RX UE receives the CSI-RS from the sidelink TX UE (i.e., an index of a slot in which reception is performed or an index of a symbol in the slot) to a time point at which the sidelink RX UE transmits a CSI report to the sidelink TX UE (i.e., an index of a slot in which the CSI report is transmitted or an index of a symbol in the slot). In this case, the time unit can be a slot or one or more OFDM symbols.

[0092] 7. Parameters for controlling sidelink TX power

[0093] (1) A sidelink path loss estimation value can be required to control sidelink transmission power. In addition, if the Uu carrier and the sidelink carrier of the base station are the same, sidelink transmission power control can be performed based on a downlink path loss estimation value in order to reduce interference caused by sidelink transmission to an uplink signal received by the reception end of the base station. To this end, the base station can perform a configuration associated with whether the TX UE needs to set a sidelink transmission power value based on a sidelink path loss estimation value, based on a downlink path loss estimation value, or based on both the sidelink path loss estimation value and the downlink path loss estimation value. For example, if the base station configures an SSB or a downlink CSI-RS to be a signal to be used to estimate path loss, the UE can set a sidelink transmission power value based on a downlink path loss value. If the base station configures a sidelink demodulation reference signal (DMRS) or a sidelink CSI-RS to be a signal to be used to estimate path loss, the UE can set a sidelink transmission power value based on a sidelink path loss value.

[0094] (2) As described above, the transmission power parameter configured for the UE can be different depending on the signal used for path loss estimation.

[0095] Although it is described that the above information is included in the resource pool configuration for sidelink communication, the disclosure is not limited thereto. That is, the above information can be configured for the sidelink TX UE or the sidelink RX UE independently of the resource pool configuration.

[0096] As Figure 4 indicated, if the sidelink TX UE has data to be transmitted to the sidelink RX UE in operation S420, the sidelink TX UE can request a sidelink resource for transmission to the sidelink RX UE using a scheduling request (SR) and / or a buffer status report (BSR) in operation S425. The base station that receives the BSR can identify that the sidelink TX UE has data for sidelink transmission, and can determine a resource required for sidelink transmission based on the BSR.

[0097] According to an embodiment, in operation S430, the base station can transmit, to the sidelink TX UE, a sidelink scheduling grant including at least one of resource information for sidelink control information (SCI) transmission, resource information for sidelink data transmission, and resource information for sidelink feedback transmission. The sidelink scheduling grant can be information for dynamic scheduling in a sidelink, and can be downlink control information (DCI) transmitted on a physical downlink control channel (PDCCH). If the base station is an NR base station, the sidelink scheduling grant can include at least one of a bandwidth part (BWP) in which sidelink transmission is performed and a carrier indicator field (CIF) or a carrier frequency indicator. If the base station is an LTE base station, only the CIF can be included. In addition, the sidelink scheduling grant can further include feedback information associated with sidelink data, i.e., information related to resource allocation of a PSFCH in which ACK / NACK information is transmitted. If the sidelink transmission corresponds to groupcast, the resource allocation information can include information for allocating multiple PSFCH resources for multiple UEs in a group. In addition, the information related to resource allocation for feedback information can be information indicating at least one of a plurality of feedback information resource candidate sets configured via higher layer signaling.

[0098] According to an embodiment, in operation S435, the sidelink TX UE that receives the sidelink scheduling grant can transmit SCI scheduling sidelink data according to the sidelink scheduling grant to the sidelink RX UE via a physical sidelink control channel (PSCCH), and can transmit the sidelink data via a physical sidellink shared channel (PSSCH). The SCI can include at least one of resource allocation information for sidelink data transmission, modulation and coding scheme (MCS) information applied to the sidelink data, group destination ID information, source ID information, unicast destination ID information, power control information for controlling sidelink power, timing advance (TA) information, DMRS configuration information for sidelink transmission, and information related to repetition groupcast transmission (e.g., information associated with the number of times repetition groupcast transmission is performed, and information related to resource allocation when repetition groupcast transmission is performed), redundancy version (RV), and HARQ process ID. In addition, the SCI can further include feedback information associated with the sidelink data, i.e., information indicating a resource in which ACK / NACK information is transmitted. In addition, the SCI can include information associated with the priority of the corresponding packet.

[0099] According to an embodiment, the sidelink RX UE which receives the SCI can receive the sidelink data. Subsequently, in operation S440, the sidelink RX UE can transmit ACK / NACK information indicating whether decoding of the sidelink data is successfully performed or failed to the sidelink TX UE via a physical sidelink feedback channel (PSFCH). The feedback information transmission associated with the sidelink can be applied to unicast transmission or groupcast transmission, but does not exclude broadcast transmission. If the sidelink transmission corresponds to groupcast transmission, UEs which receive the groupcast data can use different PSFCH resources to transmit the feedback information. Alternatively, each UE which receives the groupcast data can use the same PSFCH resource to transmit the feedback information. In this case, feedback can be performed using only NACK information. That is, in the case of ACK, the UE which receives the data can not perform feedback. In this case, the PSFCH resource can include a resource identified using a code such as a scrambling code, an orthogonal cover code, etc., and a resource identified using a different sequence or a cyclic shift applied to a sequence, in addition to a resource identified in a time domain and / or a frequency domain.

[0100] According to an embodiment, the base station can perform configuration via system information or RRC, such that the sidelink TX UE reports the HARQ feedback received from the sidelink RX UE. In this case, in operation S445, the sidelink TX UE can transmit the sidelink HARQ feedback received from the sidelink RX UE to the base station via a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH). Further, the base station can perform configuration associated with whether to enable the sidelink TX UE to multiplex the sidelink HARQ feedback information (received from the sidelink RX UE) and uplink control information (UCI) (associated with the existing Uu) and transmit the same.

[0101] According to an embodiment, in the case that the base station does not perform configuration associated with multiplexing of the sidelink HARQ feedback information and the UCI information, the sidelink TX UE can not multiplex the sidelink HARQ feedback information and the uplink control information (UCI) associated with the Uu, and can not transmit the same via a single PUCCH. In this case, the base station can independently configure a PUCCH for transmitting the sidelink HARQ feedback information and a PUCCH for transmitting the UCI information. That is, the PUCCH via which the sidelink HARQ feedback information is transmitted can exist independently, and can not transmit any UCI information via the corresponding PUCCH.

[0102] Unlike the above, if the base station performs a configuration such that the sidelink HARQ feedback information and the UCI information are multiplexed, the sidelink TX UE can multiplex the sidelink HARQ feedback information and the UCI information, and can transmit the multiplexed information via a single PUCCH. If it is assumed that the sidelink HARQ feedback information is N1 bits and the UCI information is N2 bits, the order of multiplexing the information can conform to N2+N1 (i.e., the sidelink HARQ feedback information is multiplexed after the UCI information). If a code rate associated with the sum of the sidelink HARQ feedback bits and the UCI bits that are multiplexed and transmitted via the corresponding PUCCH is greater than a code rate set by the base station, the sidelink TX UE can abandon the transmission of the sidelink HARQ feedback information (i.e., drop the sidelink HARQ feedback information).

[0103] Figure 4 A scenario is assumed in which the sidelink TX UE is in a state having an uplink connection to the base station (i.e., an RRC connected state), and both the sidelink TX UE and the sidelink RX UE exist in a coverage area of the base station. Although not shown in Figure 4 , if the sidelink TX UE does not establish an uplink connection to the base station (i.e., an RRC idle state), the sidelink TX UE can perform a random access procedure to establish an uplink connection to the base station. Also, although not shown in Figure 4 , in a scenario in which the sidelink TX UE exists within the coverage area of the base station and the sidelink RX UE exists outside the coverage area of the base station, the sidelink RX UE can perform sidelink communication using the information pre-configured as described above. As Figure 4 indicated, the base station can configure the sidelink TX UE with information for sidelink communication. According to an embodiment, if both the sidelink TX UE and the sidelink RX UE exist outside the coverage area of the base station, the sidelink TX UE and the sidelink RX UE can perform sidelink communication using the information pre-configured as described above. In this case, the meaning of pre-configuration can include using a value contained in the UE at the time of manufacturing the UE. Alternatively, if the sidelink TX UE or the sidelink RX UE has an experience of previously accessing the base station and obtaining information associated with sidelink communication via RRC configuration, or has an experience of obtaining information associated with sidelink communication via system information of the base station, the meaning of pre-configuration can include using the latest obtained information.

[0104] Also, although not shown in Figure 4 , it is assumed that, before transmitting the SR / BSR to the base station, the sidelink TX UE completes performing service discovery with the sidelink RX UE, direct link connection establishment between UEs, and PC5 RRC establishment via the procedures mentioned in Figure 3 .

[0105] Figure 5 is a diagram illustrating a sidelink unicast communication procedure according to an embodiment of the disclosure.

[0106] Specifically, Figure 5 is a diagram illustrating a sidelink communication procedure based on a resource allocation mode 2 described in Figure 2 In Figure 5 , in operation S510, the base station configures a sidelink transmission and reception UE with parameters for sidelink communication via system information in a cell. In this case, the parameters can include at least one of the parameter information illustrated in Figure 4

[0107] As illustrated in Figure 5 , if the sidelink TX UE has data to be transmitted to the sidelink RX UE in operation S520, the sidelink TX UE can transmit SCI to the sidelink RX UE via a PSCCH and can transmit sidelink data to the sidelink RX UE via a PSSCH in operation S525. According to an embodiment, the SCI can include at least one of information for resource allocation information for sidelink data transmission, MCS information applied to sidelink data, group destination ID information, source ID information, unicast destination ID information, power control information for controlling sidelink power, timing advance information, DMRS configuration information for sidelink transmission, and information related to repetition packet transmission (for example, information associated with the number of times repetition packet transmission is performed, and information related to resource allocation when repetition packet transmission is performed), redundancy version (RV), and HARQ process ID. In addition, the SCI can include information indicating a resource in which feedback information (A / N information) associated with sidelink data is transmitted.

[0108] ​According to an embodiment, a sidelink RX UE which receives the SCI can receive the sidelink data. Subsequently, in operation S530, the sidelink RX UE can transmit ACK / NACK information indicating whether decoding of the sidelink data is successfully performed or failed to the sidelink TX UE via a PSFCH. The feedback information transmission associated with the sidelink can be applied to unicast transmission or groupcast transmission, but does not exclude broadcast transmission. If the sidelink transmission corresponds to groupcast transmission, UEs which receive the groupcast data can use different PSFCH resources to transmit the feedback information. Alternatively, the UEs which receive the groupcast data can use the same PSFCH resource to transmit the feedback information. In this case, only NACK information can be fed back (i.e., if the UE which receives the data determines ACK, the UE does not perform feedback). In this case, the PSFCH resource can include a resource identified using a code such as a scrambling code, an orthogonal cover code, etc., as well as a resource identified using a different sequence (as well as a cyclic shift applied to the sequence) in addition to the resource identified in the time domain and / or the frequency domain.

[0109] As Figure 4 indicated, Figure 5 a base station in the system information or RRC can perform configuration such that the sidelink TX UE reports the HARQ feedback received from the sidelink RX UE. In this case, in operation S535, the sidelink TX UE can transmit the sidelink HARQ feedback received from the sidelink RX UE to the base station via a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH). In addition, the base station can perform configuration associated with whether to enable the sidelink TX UE to multiplex the sidelink HARQ feedback information (received from the sidelink RX UE) and uplink control information (UCI) (associated with the existing Uu) and transmit the same.

[0110] In the case where the base station does not perform configuration associated with multiplexing the sidelink HARQ feedback information and the UCI information, the sidelink TX UE can not multiplex the sidelink HARQ feedback information and the uplink control information (UCI) associated with the Uu, and can not perform transmission via a single PUCCH. In this case, the base station can independently configure a PUCCH for transmitting the sidelink HARQ feedback information and a PUCCH for transmitting the UCI information. That is, the PUCCH via which the sidelink HARQ feedback information is transmitted can exist independently, and can not transmit any UCI information via the corresponding PUCCH.

[0111] Unlike the above, if the base station performs a configuration such that the sidelink HARQ feedback information and the UCI information are multiplexed, the sidelink TX UE can multiplex the sidelink HARQ feedback information and the UCI information, and can transmit the multiplexed information via a single PUCCH. If it is assumed that the sidelink HARQ feedback information is N1 bits and the UCI information is N2 bits, the order of multiplexing the information can conform to N2+N1 (i.e., the sidelink HARQ feedback information is multiplexed after the UCI information). If a code rate associated with the sum of the sidelink HARQ feedback bits and the UCI bits multiplexed and transmitted via the corresponding PUCCH is greater than a code rate set by the base station, the sidelink TX UE can abandon the transmission of the sidelink HARQ feedback information (i.e., discard the sidelink HARQ feedback information).

[0112] Figure 5 A scenario is assumed in which both the sidelink TX UE and the sidelink RX UE exist within the coverage of the base station. Although not shown in Figure 5 , the present disclosure can also be applied to a case in which both the sidelink TX UE and the sidelink RX UE exist outside the coverage area of the base station. In this case, the sidelink TX UE and the sidelink RX UE can have preconfigured information for sidelink communication. Further, although not shown in Figure 5 , the present disclosure can also be applied to a scenario in which one of the sidelink TX UE and the sidelink RX UE exists within the coverage area of the base station and the other UE exists outside the coverage area of the base station. In this case, the base station can configure information for sidelink communication of the UE within the coverage area of the base station, and can preconfigure information for sidelink communication of the UE outside the coverage area of the base station. In this case, the "information for sidelink communication" can be interpreted as information associated with at least one of the parameters for sidelink communication that have been described with reference to Figure 4 . In this case, the meaning of preconfiguration can include using a value contained in the UE at the time of manufacturing the UE. Alternatively, if the sidelink TX UE or the sidelink RX UE has an experience of previously accessing the base station and obtaining information associated with sidelink communication via RRC configuration, or has an experience of obtaining information associated with sidelink communication via system information of the base station, the meaning of preconfiguration can include using the latest obtained information.

[0113] Although not shown in Figure 5 , it is assumed that, before transmitting the PSCCH / PSSCH to the sidelink RX UE, the sidelink TX UE completes performing service discovery, direct link establishment, and PC5 RRC establishment with the sidelink RX UE via the procedures mentioned in Figure 3 .

[0114] Although the description is provided using unicast communication in which a single sidelink RX UE exists as an example, the disclosure can be equally applied to groupcast communication and broadcast communication in which two or more sidelink RX UEs exist.

[0115] Figure 6 is a diagram illustrating a structure of a sidelink synchronization channel according to an embodiment of the disclosure.

[0116] The sidelink synchronization channel can be used interchangeably with a sidelink synchronization single block (S-SSB), and a single S-SSB can include 14 symbols, as Figure 6 indicated. The single S-SSB can include a sidelink primary synchronization signal (S-PSS), a sidelink secondary synchronization signal (S-SSS), a physical sidelink broadcast channel (PSBCH), and a guard period (GAP). In this case, each of the S-PSS and the S-SSS can include two OFDM symbols, the PSBCH can include 10 OFDM symbols, and the GAP can include a single OFDM symbol.

[0117] In this case, as Figure 6 indicated, the S-PSS is mapped to OFDM symbol indices #1 and #2, the S-SSS can be mapped to OFDM symbol indices #3 and #4, and the GAP can be mapped to the last OFDM symbol of the S-SSB (i.e., OFDM symbol index #13). The PSBCH can be mapped to the remaining OFDM symbols (excluding the symbols used for the S-PSS, the S-SSS, and the GAP). Although Figure 6 indicates that the S-PSS and the S-SSS are located in consecutive symbols, the S-PSS and the S-SSS can be spaced apart from each other by a single symbol. That is, the S-PSS can be mapped to OFDM symbol indices #1 and #2, the S-SSS can be mapped to OFDM symbol indices #3 and #4, and the PSBCH can be mapped to OFDM symbol indices #0, #5, #6, #7, #8, #9, #10, #11, #12, and #13. Although not indicated in Figure 6 , a demodulation reference signal (DMRS) can be transmitted via each of the OFDM symbols to which the PSBCH is mapped.

[0118] Figure 7 is a diagram illustrating a structure of a sidelink control channel and a data channel according to an embodiment of the disclosure.

[0119] In Figure 7 , a sidelink control channel (physical sidelink control channel (PSCCH)) can include K1 symbols and N1 frequency blocks (RBs). Also, a sidelink data channel (physical sidelink data channel (PSSCH)) can include N2 RBs in K1 symbols and M RBs in remaining K2 symbols. In Figure 7 , it is shown that the PSFCH includes K3 symbols and M RBs, and the number of RBs included in the PSSCH and the number of RBs included in the PSFCH are the same. However, the resource magnitude of the PSFCH on the frequency axis can be smaller than the number of RBs included in the PSSCH. For example, the PSSCH can include 10 RBs, and the PSFCH can include one RB.

[0120] In Figure 7 , K1 and K2 can be the same as or different from each other. Also, if K1 and K2 are different from each other, K1 > K2 or K1 < K2. According to an embodiment, K1 + K2 + guard symbol 1 + K3 + guard symbol 2 ≤ K, and guard symbol 1 and guard symbol 2 can be one symbol or two or more OFDM symbols. In this case, guard symbol 1 and guard symbol 2 can be OFDM symbols of different lengths. For example, guard symbol 1 can include two OFDM symbols, and guard symbol 2 can include one OFDM symbol.

[0121] According to an embodiment, as Figure 7 shown, a sidelink TX UE can transmit sidelink control information (SCI) via a PSCCH including K1 symbols on a time axis and N2 frequency blocks on a frequency axis. The sidelink control information can include time / frequency allocation information of a PSSCH including K1 + K2 symbols on a time axis and M frequency blocks on a frequency axis, and can be transmitted. A sidelink RX UE can receive and decode the PSCCH transmitted from the TX UE, can obtain the time / frequency allocation information of the PSSCH, and can decode the PSSCH. Although Figure 7 K2 symbols of the PSSCH are shown to be physically continuously located after K1 symbols included in the PSCCH, K2 symbols of the PSSCH can not be physically continuous (i.e., they can be logically continuous but not physically continuous).

[0122] According to an embodiment, in Figure 7In this context, when a sidelink TX UE sends PSCCH and PSSCH to one or more sidelink RX UEs and receives PSFCH from one or more sidelink RX UEs, protection symbol 1 (GAP-1) can be used. That is, protection symbol 1 (GAP-1) can be the interval required for switching between PSCCH / PSSCH transmission and PSFCH reception from the perspective of the sidelink TX UE, and can also be the interval required for switching between PSCCH / PSSCH reception and PSFCH transmission from the perspective of the sidelink RX UE.

[0123] and Figure 7 The structure of the sidelink time slots shown differs, and a time slot in which the PSFCH is absent can be considered. In this case, the sidelink time slot may include K1 frequency-division multiplexed PSCCH / PSSCH symbols, K2 PSSCH symbols, and a guard symbol (GAP-2) at the end of the time slot. That is, the sidelink TX UE can use the remaining symbols (i.e., K-(K1+1) symbols, where in this case, we assume the number of symbols in GAP-2 is 1) after excluding the K1 frequency-division multiplexed PSCCH / PSSCH symbols from the K symbols included in the sidelink time slot, to transmit the PSSCH.

[0124] although Figure 7 The diagram shows the PSCCH located in the middle of the side link time slot on the frequency axis, but this disclosure is not limited thereto. For example, the PSCCH may have N1 RBs from either the lowest or highest RB index.

[0125] Figure 8 This is a diagram illustrating an example of the process by which a V2X UE transmits a sidelink feedback channel in a wireless communication system according to various embodiments of the present disclosure. Specifically, Figure 8 This is a diagram illustrating another example of a signal processing method for transmitting a sidelink feedback channel by a V2X UE according to an embodiment of the present disclosure.

[0126] refer to Figure 8 In operation S801, the NR V2X receiving (RX) UE may have parameters for transmitting the sidelink feedback channel, which include at least one of the following information.

[0127] 1. Information associated with PSFCH code resources: In this case, code resources may include resources for code identification using codes such as scrambling codes, orthogonal overlay codes, etc., that can be used for PSFCH, and resources for identification using different sequences (and cyclic shifts applied to the sequences). For example, if HARQ-ACK / NACK is sent via PSFCH, this information may be the CS value to be used for ACK and the CS value to be used for NACK.

[0128] 2. Information associated with PSFCH format: For example, if it is assumed that two PSFCH formats are supported, PSFCH format 1 can be used to transmit 2 bits or less of SFCI information, and PSFCH format 2 can be used to transmit 3 bits or more of SFCI information. Thus, in this example, the information associated with the PSFCH format can be PSFCH format 1 or PSFCH format 2.

[0129] In operation S802, the NR V2X RX UE can generate SFCI information to be transmitted via the PSFCH according to configuration or indication from the base station or the NR V2X transmission (TX) UE.

[0130] 1. For example, it can be configured or indicated whether to transmit only NACK information or to transmit ACK information and NACK information separately.

[0131] In operation S803, a sequence can be generated using the SFCI information generated in operation S802 and one of the methods described in operation S801.

[0132] 1. In this case, a single sequence can be mapped to a single piece of SFCI information. For example, 1-bit ACK information can be sequence 1, and 1-bit NACK information can be sequence 2. Also, 2-bit ACK information can be sequence 3, and 2-bit NACK information can be sequence 4. In an example, different sequences mean that different CS values are used. More specifically, in this example, if 1-bit ACK / NACK information is transmitted, ACK information can use CS=0, and NACK information can use CS=6. Similarly, if 2-bit ACK / NACK information is transmitted, (ACK, ACK) information can use CS=0, (ACK, NACK) information can use CS=3, (NACK, ACK) information can use CS=6, and (NACK, NACK) information can use CS=9.

[0133] 2. In this example, the length of the sequence can be proportional to the amount of frequency resources configured or indicated by the base station or the V2X TX UE for transmitting the PSFCH. For example, if the size of the PSFCH frequency resource is configured or indicated as "1", the length of the sequence that the V2X RX UE needs to generate is 12x1=12. If the size of the PSFCH frequency resource is configured or indicated as "2", the length of the sequence that the V2X RX UE needs to generate is 24x2=12.

[0134] 3. As another example of the configuration of the sequence length, the base station or the V2X TX UE can configure or indicate a set of sizes of the frequency resources that the V2X RX UE can use, and the V2X RX UE can select and use one size from the corresponding set. In this case, a criterion for the selection can be determined based on a reception quality of the PSCCH and / or the PSSCH received by the V2X RX UE from the V2X TX UE. For example, if the reception quality is good, a sequence having a short length can be selected. That is, a frequency resource having a small size can be used. If the reception quality is poor, a sequence having a long length can be selected. The base station or the V2X TX UE can configure or indicate a threshold for providing a criterion for the V2X RX UE to determine whether the reception quality is good or poor. Specifically, if a quality value of a channel received by the V2X RX UE is lower than, or lower than or equal to, a threshold configured or indicated by the base station or the V2X TX UE, it is determined that the quality of the channel is poor. Otherwise, it is determined that the quality of the channel is good.

[0135] In operation S804, the generated sequence can be mapped to frequency resources (resource elements (REs)) that are physical resources of the PSFCH. Although not shown in FIG. 8, after operation S804, an OFDM symbol can be generated via an inverse fast Fourier transform (IFFT), a cyclic prefix (CP) can be added to the OFDM symbol, and the OFDM symbol can be transmitted to an antenna. Figure 8

[0136] Although unicast communication including a single NR V2X RX UE is mainly described in the examples, the disclosure can be extended to groupcast communication including two or more NR V2X RX UEs.

[0137] Figure 9 FIG. 9 is a diagram illustrating a structure of a sidelink feedback channel according to an embodiment of the disclosure.

[0138] Figure 9 FIG. 9 illustrates a structure of a single sidelink feedback channel (PSFCH) that the TX UE can transmit, and the PSFCH can be used to transmit sidelink HARQ feedback information described in Figure 4 and Figure 5 Although it is assumed that the DMRS overhead is 1 / 3 (i.e., 4 REs out of 12 resource elements (REs) are used as DMRS), the disclosure is not limited thereto. For example, if the DMRS overhead is 1 / 4 (i.e., 3 REs out of 12 REs are used as DMRS), the DMRS can be mapped to RE indices #1, #5, and #9 (or #2, #6, and #10), and the sidelink HARQ feedback information can be mapped to the remaining RE indices.

[0139] Although in​Figure 9 The structure of a single PSFCH including a single RB (i.e., 12 REs) is shown in Figure 8 the same manner, the disclosure can be equally applied to a single PSFCH including two or more RBs. That is, if it is assumed that two RBs correspond to the size of a single PSFCH frequency resource transmitted by a sidelink RX UE, the DMRS can be mapped to RE indices #1, #4, #7, #10, #13, #16, #19, and #22, and the sidelink HARQ feedback information can be mapped to the remaining RE indices.

[0140] In Figure 8 , if a single PSFCH transmitted by a single sidelink RX UE includes two or more OFDM symbols on the time axis, the PSFCH including one OFDM symbol is repeated. However, in the example of Figure 9 , the DMRS exists only in the odd-numbered OFDM symbols, but not in the even-numbered OFDM symbols (i.e., the DMRS exists in the first and third OFDM symbols, but not in the second OFDM symbol).

[0141] Figure 9 The PSFCH of Figure 7 may be mapped to K3 symbols in the sidelink slot resource of Figure 9 Although not shown in , the sidelink HARQ feedback information can be mapped to all REs of the PSFCH without REs for transmitting the DMRS (i.e., without the DMRS).

[0142] In addition, Figure 9 shows that the DMRS exists in the same RE on the frequency axis, although the number of OFDM symbols is increased, but the disclosure is not limited thereto. That is, in the case of a PSFCH including 3 OFDM symbols, the position of the DMRS RE in the third OFDM symbol can be different from that of the DMRS RE existing in the first OFDM symbol. In the same manner, in the case of a PSFCH including 4 or more OFDM symbols, the positions of the DMRS RE in each OFDM symbol in which the DMRS exists can be different from each other. As another example, in the case of a PSFCH including 4 or more OFDM symbols, the positions of the DMRS RE in at least two or more OFDM symbols in which the DMRS exists can be the same.

[0143] Figure 10 is a diagram showing an example of controlling sidelink transmission power according to an embodiment of the disclosure.

[0144] In Figure 10In the middle, it is assumed that UE1 is located near a base station (gNB), and UE2 is far from the gNB (i.e., UE1 is located at the center of a cell, and UE2 is located at the edge of the cell). It is assumed that UE1 and UE2 perform sidelink communication, UE1 is a sidelink TX UE, and UE2 is a sidelink RX UE. In this case, UE1 can control the sidelink transmission power of the sidelink transmission. The parameters of the sidelink transmission power of UE1 can include at least P0, α, a path loss estimation value, and the size of the allocated frequency block, as shown in Equation 1.

[0145] [Equation 1]

[0146] Sidelink TX power

[0147] = min{Pcmax, P Congestion , P0+ α·PL+ 10log10(M·2 μ )+ Δ} [dBm]

[0148] In Equation 1, each parameter is defined as follows.

[0149] -Pcmax: denotes the maximum transmission output of the UE determined by the UE based on a P-max value configured by the base station via system information or RRC, if the base station does not exist, a pre-configured value, a power class of the UE contained in the UE, etc.

[0150] -P Congestion : a parameter that reflects the congestion level of the sidelink TX UE and indicates the maximum transmission power that the sidelink TX UE can use based on the congestion level. Specifically, if the base station determines that the congestion level is high in the resource pool configured by the base station, the base station can transmit the P Congestion value to the sidelink TX UE via system information or RRC configuration. As another example, when a unicast link is connected via PC5 RRC, the sidelink TX UE can be configured with the P Congestion value. As another example, the sidelink TX UE can use the P Congestion value included in the pre-configured resource pool information. The P Congestion value can be expressed in dBm and can be in the range of -41 dBm to 31 dBm at intervals of 1 dBm. The P Congestion value can have an association relationship with the priority of the sidelink channel transmitted by the sidelink TX UE. That is, if the priority of the sidelink channel transmitted by the sidelink TX UE is high, it is necessary to successfully perform transmission of the sidelink channel even if the congestion level is high. Therefore, the P CongestionThe value can be high (e.g., 31 dBm). In contrast, if the priority of the sidelink channel transmitted by the sidelink TX UE is low and the degree of congestion is high, it does not matter whether the transmission of the sidelink channel fails (or the transmission is abandoned). Accordingly, the P Congestion The value can be low (e.g., -41 dBm). The above-described sidelink channel can include a sidelink synchronization channel.

[0151] -P0: denotes a value configured or pre-configured by a base station via system information or RRC in order to secure the link quality of a reception UE (if the base station does not exist, it is a pre-configured value).

[0152] -α: denotes a parameter for performing compensation associated with a path loss value, which has a value in the range of 0 to 1, and indicates a value configured by a base station via system information or RRC (if the base station does not exist, it is a pre-configured value). For example, if α = 1, 100% compensation can be performed for the path loss. If α = 0.8, only 80% compensation can be performed for the path loss.

[0153] -M: denotes the size of a frequency block allocated for sidelink transmission. In this case, 2 μ may be a parameter for performing compensation associated with a power spectral density (PSD) that is different depending on a subcarrier spacing. For example, in the case of using a subcarrier spacing of 15 kHz, μ = 0. If the subcarrier spacing is increased to 30 kHz, which is twice as before, although the same number of frequency blocks is used, the PSD can be reduced to half of the PSD in the case of a subcarrier spacing of 15 kHz. Accordingly, in order to compensate, the power needs to be increased to twice. More specifically, if two frequency blocks are used, for example, in the case of a subcarrier spacing of 15 kHz, 10log10(2×2 0 ) = 3 dB can be required. However, in the case of a subcarrier spacing of 30 kHz, in order to maintain the same PSD as in the case of a subcarrier spacing of 15 kHz, the transmission power needs to be increased to 10log10(2×2 1 ) = 6 dB.

[0154] -PL: denotes a path loss estimation value. In this case, the path loss value can be estimated according to Equation 2.

[0155]

Equation 2

[0156] Transmission power of a signal for estimating a path loss - Reference signal received power (RSRP) measurement value of a signal for estimating a path loss

[0157] Equation 2 can be differently applied depending on the following scenarios.

[0158] • If the signal used to estimate the path loss is a sidelink signal: UE1, which is a sidelink TX UE, can transmit a sidelink reference signal to UE2, which is a sidelink RX UE. UE2 can receive the sidelink reference signal, can measure the RSRP value, and can report the RSRP value to UE1. In this case, the RSRP value can be transmitted via PSFCH or PSSCH. If the RSRP value is transmitted via PSSCH, the RSRP value can be transmitted in the MAC layer or the RRC layer. UE1 can estimate the sidelink path loss value using Equation 2 based on the transmission power of the reference signal transmitted to UE2 and the RSRP value reported from UE2. As another example, UE1 can transmit information associated with the transmission power of the reference signal transmitted by UE1 to UE2. UE2, which receives the information, can measure the RSRP value from the reference signal transmitted by UE1 and can estimate the path loss value based on Equation 2. UE2 can transmit the estimated sidelink path loss value to UE1 via PSFCH or PSSCH. If the sidelink path loss estimate value is transmitted via PSSCH, a MAC CE can be used. If the distance between UE1 and UE2 is farther than the distance between UE1 and the gNB, the sidelink signal transmitted by UE1 can cause interference to the reception signal of the gNB. It will be referred to Figure 11 and Figure 12 This will be described in detail.

[0159] Figure 11 and Figure 12 is a diagram showing interference caused by a frequency block transmitted by a sidelink UE to adjacent frequency blocks according to an embodiment of the disclosure.

[0160] Referring to Figure 11 If the distance between UE1 and UE2 is farther than the distance between UE1 and the gNB, the sidelink signal transmitted by UE1 can cause interference to the reception signal of the gNB. For example, Figure 11 and Figure 12 shows an example of the degree of interference caused by a sidelink signal to a reception signal of a gNB. In Figure 11 , it is assumed that sidelink control information or data information is transmitted in resource block index #12 (one resource block is used). Also, in Figure 12 , it is assumed that 5 resource blocks corresponding to resource block indexes #12 to #17 are used to transmit sidelink control information or data information. In Figure 11 , sidelink transmission is performed only at resource block index #12, and thus, transmission power should be generated at the corresponding resource index. However, due to interference (in-band emission), transmission power can be generated at adjacent resource indexes (for example, indexes #9, #10, #11, #13, #14, and #15). AsFigure 12 As shown, as the number of resource blocks allocated to the sidelink transmission increases, the amount of interference can become more severe. Thus, a sidelink TX UE located near a gNB can need to use a low transmission power so as not to cause interference to the uplink reception signal of the gNB.

[0161] • If the signal used to estimate the path loss is a downlink signal of the gNB: In order to reduce interference to the reception signal of the gNB, UE1 as a sidelink TX UE can apply a downlink path loss value associated with the gNB to Equation 1. Specifically, the downlink path loss value can be estimated by UE1 based on a CSI reference signal (CSI-RS) transmitted by the gNB. As another example, UE1 can estimate the downlink path loss value using a secondary synchronization signal (SSS) transmitted by the gNB, or can estimate the downlink path loss value using both the SSS and a demodulation reference signal (DMRS) transmitted via a physical broadcast channel (PBCH). In this case, UE1 can estimate the downlink path loss substantially using the SSS, and can determine whether to additionally use the DMRS transmitted via the PBCH depending on the implementation of UE1. As another example, UE1 can estimate the downlink path loss value using a reference signal (channel state information reference signal (CSI-RS)) for obtaining channel information transmitted by the gNB. Which signal (SSS and CSI-RS) to be used when UE1 estimates the downlink path loss value can differ depending on the connection state between UE1 and the gNB. For example, if UE1 is in a state in which it is RRC-connected with the gNB (RRC-connected state), the gNB can configure UE1 with information indicating which signal needs to be used for estimating the downlink path loss value. If UE1 is in a state in which it is RRC-disconnected with the gNB (RRC-idle state), UE1 can estimate the downlink path loss value using the SSS or both the SSS and a demodulation reference signal (DMRS) transmitted via the PBCH. In this case, as described above, UE1 can estimate the downlink path loss substantially using the SSS, and can determine whether to additionally use the DMRS transmitted via the PBCH depending on the implementation of UE1. The gNB can transmit information associated with the transmission power of the reference signal to UE1 via system information or RRC configuration, and UE1 can measure an RSRP value using the reference signal transmitted from the gNB. UE1 can estimate the downlink path loss value using Equation 2 based on the transmission power value of the reference signal transmitted from the gNB and the measured RSRP value. By using the downlink path loss value, interference to the reception signal of the gNB as shown can be overcome. Figure 11 and Figure 12 the reception signal of the gNB as shown can be overcome.

[0162] • The gNB can perform a configuration associated with a reference signal to be used by the UE for estimating a path loss (PL) in Equation 1 (i.e., whether to need to use SSS or CSI-RS to estimate a downlink path loss or whether to need to use a sidelink reference signal to estimate a sidelink path loss).

[0163] - Δ: denotes a TPC command for controlling a closed-loop power, or can be another RRC parameter. For example, this can be an offset value of a transmission power based on a format of a sidelink feedback channel. As another example, this can be a compensation value of a transmission power based on a spectral efficiency of a sidelink feedback channel. That is, when the spectral efficiency is high (i.e., a case where a same amount of bits is transmitted using a smaller amount of resources or a case where more bits are transmitted in a same resource), a high transmission power needs to be used. Thus, this can be a parameter based on a spectral efficiency to perform a compensation associated with a transmission power value. Although Δ is shown to include a single parameter in Equation 1, Δ can include a combination of two or more parameters.

[0164] Figure 13 is a diagram illustrating a method of controlling a transmission power of a sidelink synchronization channel according to an embodiment of the disclosure.

[0165] According to an embodiment, whether to transmit a sidelink synchronization channel can differ based on a capability of a sidelink UE. That is, a sidelink UE having a capability of transmitting a sidelink synchronization channel can transmit the sidelink synchronization channel in response to a command from a base station. In this case, the sidelink UE can be in a state of being RRC-connected with the base station (RRC-connected state), and the base station can command the sidelink UE to transmit the sidelink synchronization channel via RRC or downlink control information (DCI).

[0166] As another example, a sidelink UE having a capability of transmitting a sidelink synchronization channel can determine whether the UE itself transmits the sidelink synchronization channel. In this case, the sidelink UE can be within a coverage area of a base station but can be in an RRC-idle state. In this case, the base station can configure a threshold value of a downlink reference signal received power (RSRP) via sidelink dedicated system information (system information block (SIB)). The sidelink UE receiving the system information from the base station can compare a downlink RSRP value (R_measure) measured by itself and received in a downlink with a downlink RSRP threshold value (R_threshold), and can transmit the sidelink synchronization channel. More specifically, if R_measure < R_threshold or R_measure ≤ R_threshold, the sidelink UE can transmit the sidelink synchronization channel.

[0167] In addition to the command associated with the transmission of the sidelink synchronization channel, the base station can transmit, to the sidelink UE, a transmission power parameter for the transmission of the sidelink synchronization channel via system information and / or RRC configuration in operation S1310, as shown in Equation 1. Figure 13 In this case, the transmission power parameter for the transmission of the sidelink synchronization channel can be at least one of P0, α, μ, M, and Δ values in Equation 1.

[0168] Further, the transmission power parameter for the transmission of the sidelink synchronization channel can include information associated with whether to need to estimate a downlink path loss to configure a transmission power value, whether to need to estimate a sidelink path loss to configure a transmission power value, or whether to need to estimate both a downlink path loss and a sidelink path loss to configure a transmission power value. The information can be transmitted from the base station to the UE via system information or RRC, and the information can be at least one of the following information.

[0169] 1) Transmit link information that the UE needs to estimate a path loss via an indication of a reference signal type or configuration

[0170] That is, the base station can transmit information associated with a link that the UE can use to estimate a path loss (PL) by indicating a reference signal to be used among a downlink SSB, a downlink CSI-RS, or a DMRS of a sidelink data channel. For example, based on an agreement between the base station and the UE, if an indicator index is 0, it indicates a downlink SSB. If the indicator index is 1, it indicates a downlink CSI-RS. If the indicator index is 2, it indicates a DMRS of a sidelink data channel. If the indicator index is 3, it indicates that both a downlink SSB and a DMRS of a sidelink data channel can be used. If the indicator index is 4, it indicates that both a downlink CSI-RS and a DMRS of a sidelink data channel can be used. As another example, a type of a reference signal that the UE needs to estimate a path loss can be explicitly included in system information or RRC configuration information.

[0171] 2) Transmit link information that the UE needs to estimate a path loss via a transmission power parameter such as P0, α, etc.

[0172] That is, the base station can differently configure a transmission power parameter for applying a downlink path loss and a transmission power parameter for applying a sidelink path loss. The UE receiving the information can determine whether to apply the downlink path loss or the sidelink path loss. More specifically, the base station can configure the P0 and α parameters in Equation 1 using different parameters by distinguishing a case where the UE needs to apply the downlink path loss and a case where the UE needs to apply the sidelink path loss. For example, if the downlink path loss needs to be applied, the base station can configure P 0_DL and α DL , and if the sidelink path loss needs to be applied, the base station can configure P 0_SL and α SL . If both the downlink path loss and the sidelink path loss need to be applied, the base station can configure P 0_DL , α DL , P 0_SL and α SL .

[0173] Using at least one of the above-described methods, when configuring the transmission power, the UE to transmit the sidelink synchronization channel can determine whether to consider the downlink path loss associated with the base station, whether to consider the sidelink path loss associated with another sidelink UE, or whether to consider both the downlink path loss and the sidelink path loss.

[0174] In addition to the above-described parameters, the transmission power parameter for the transmission of the sidelink synchronization channel can include a parameter for estimating a path loss (PL) in Equation 1, which can represent a transmission power of a reference signal for estimating a path loss in Equation 2.

[0175] More specifically, the base station can perform configuration associated with using a downlink SSB or a downlink CSI-RS via system information or RRC. The UE that receives the information and is to transmit a sidelink synchronization channel can estimate a path loss (PL) value in Equation 1 and Equation 2 using the downlink SSB or the downlink CSI-RS transmitted by the base station. In this case, if the base station performs configuration associated with using a downlink SSB, the base station can transmit information associated with SSB transmission power to the UE via system information or RRC signaling. In the same manner, if the base station performs configuration associated with using a downlink CSI-RS, the base station can transmit information associated with CSI-RS transmission power to the UE via at least one of system information, RRC, and DCI signaling. In this case, the method of signaling information associated with CSI-RS transmission power can be performed in two steps. For example, the base station can transmit information associated with SSB transmission power to the UE via system information or RRC signaling, and can transmit an offset (difference) value between SSB transmission power and CSI-RS transmission power to the UE via at least one of system information, RRC, and DCI signaling.

[0176] At least one of the transmission power parameters can be included in the sidelink resource pool configuration information. For example, P 0，1 , α1, μ1, M1, and Δ1 can be configured for the sidelink resource pool 1, and P 0，2 , α2, μ2, M2, and Δ2 can be configured for the sidelink resource pool 2. In this case, each of the transmission power parameters configured for the sidelink resource pool can be the same or different for each sidelink resource pool. That is, P 0，1 configured for the sidelink resource pool 1 and P 0，2 configured for the sidelink resource pool 2 can have the same value or different values. In the same manner, α1 configured for the sidelink resource pool 1 and α2 configured for the sidelink resource pool 2 can have the same value or different values.

[0177] As shown in Equation 3, the UE that receives the transmission power parameters can transmit a sidelink synchronization channel with a maximum transmission power if the maximum transmission power is used for transmitting the sidelink synchronization channel. Figure 13

[0178]

Equation 3

[0179] P S-PSS = P CMAX，PSBCH

[0180] P S-SSS = P CMAX，S-SSS ​

[0181] In Equation 3, P S-PSS denotes the transmission power of the S-PSS, and P S-SSS denotes the transmission power of the S-SSS. If the base station commands the transmission of the sidelink synchronization channel at the maximum transmission power, the UE can set the transmission power of the S-PSS to be equal to the maximum transmission power of the PSBCH and can perform the transmission. Also, the UE can set the transmission power of the S-SSS to be equal to the maximum transmission power of the S-SSS and can perform the transmission. In this case, the S-PSS and the PSBCH can apply the same power back-off or the same maximum power reduction (MPR), and thus the maximum transmission power of the S-PSS and the maximum transmission power of the PSBCH can be the same. However, when compared to the S-PSS / PSBCH, the S-SSS needs to apply a greater power back-off or a higher MPR, and the S-SSS can have a maximum transmission power value separately from the S-PSS / PSBCH. The reason why the power back-off of the S-PSS is different from the power back-off of the S-PSS / PSBCH is that the peak-to-average power ratio (PAPR) of the sequence (gold sequence) is worse than the PAPR of the Zadoff-chu sequence used for the S-PSS. That is, if the PAPR characteristics of the sequence used for the S-PSS and the PAPR characteristics of the sequence used for the S-SSS are similar, the S-PSS, the S-SSS, and the PSBCH can apply the same power back-off or the same MPR. In this case, Equation 3 can be replaced with the following Equation 4.

[0182]

Equation 4

[0183] P S-PSS = P S-SSS = P CMAX，PSBCH = P CMAX

[0184] P CMAX in Equation 4 can have the same meaning as P CMAX in Equation 1.

[0185] If Figure 13 the base station does not perform the indication or configuration associated with the transmission of the sidelink synchronization channel at the maximum transmission power in the cell, the UE can determine the transmission power of the S-PSS, the S-SSS, and the PSBCH using Equation 5 and Equation 6 in operation S1325.

[0186]

Equation 5

[0187] PS-PSS =P PSBCH =min{P CMAX，PSBCH 10log 10 (2 μ ·M)+P0+α·PL}[dBm

[0188] P S-SSS =min{P CMAX，S-SSS 10log 10 (2 μ ·M)+P0+α·PL}[dBm

[0189] If the downlink path loss value is applied to Equation 5, then Equation 5 can be the same as the following equation.

[0190] P S-PSS =P PSBCH =min{P CMAX，PSBCH 10log 10 (2μ·M)+P 0_DL +α DL ·PL DL [dBm]

[0191] P S-SSS =min{P CMAX，S-SSS 10log 10 (2 μ ·M)+P 0_DL +α DL ·PL DL [dBm]

[0192] If the sidelink path loss value is applied to Equation 5, then Equation 5 can be the same as the following equation.

[0193] P S-PSS =P PSBCH =min{P CMAX，PSBCH 10log 10 (2μ·M)+P 0_SL +α SL ·PL SL [dBm]

[0194] P S-SSS =min{P CMAX，S-SSS 10log 10 (2 μ ·M)+P 0_SL +α SL ·PL SL [dBm]

[0195] If both downlink path loss and sidelink path loss values ​​are applied to Equation 5, then Equation 5 can be the same as the following equation.

[0196] P S-PSS = P PSBCH = min{P CMAX，PSBCH , min(A, B)} [dBm]

[0197] P S-SSS = min{P CMAX，S-SSS , min(A, B)} [dBm]

[0198] In the equation, A = 10 log 10 (2 μ · M) + P 0_DL + a DL · PL DL , and B = 10 log 10 (2 μ · M) + P 0_SL + a SL · PL SL .

[0199] [Equation 6]

[0200] P S-PSS = P S-SSS = P PSBCH = min{P CMAX , 10 log 10 (2 μ · M) + P0 + a · PL}[dBm]

[0201] If the downlink path loss value is applied to Equation 6, Equation 6 can be the same as the following equation.

[0202] P S-PSS = P S-SSS = P PSBCH = min{P CMAX , 10 log 10 (2 μ · M) + P 0_DL + a DL · PL DL}[dBm]

[0203] If the sidelink path loss value is applied to Equation 6, Equation 6 can be the same as the following equation.

[0204] P S-PSS = P S-SSS = P PSBCH = min{P CMAX , 10 log 10 (2 μ · M) + P 0_SL + a SL · PL SL[dBm]

[0205] If both downlink path loss and sidelink path loss values are applied to Equation 6, Equation 6 can be the same as the following equation.

[0206] P S-PSS = P S-SSS = P PSBCH = min{P CMAX , min(A, B)} [dBm]

[0207] In this case, A = 10 log 10 (2 μ · M) + P 0_DL + α DL · PL DL , and B = 10 log 10 (2 μ · M) + P 0_SL + α SL · PL SL .

[0208] When S-PSS / PSBCH and S-SSS apply different backoff values or different MPRs, Equation 5 can be applied. When S-PSS / PSBCH and S-SSS are applied with the same power backoff or the same MPR, Equation 6 can be applied. In this case, P CMAX in Equation 6 can be replaced with P CMAX，PSBCH or P CMAX，S-SSS in Equation 5.

[0209] In Equation 3, Equation 4, Equation 5, Equation 6, and the modification to the mentioned equations, P 0_DL , α DL , P 0_SL , and α SL may be the same as or different from P 0_DL , α DL , P 0_SL , and α SL used to control the transmission power of the sidelink control channel and the data channel. In Equation 3, Equation 4, Equation 5, Equation 6, and the modification to the mentioned equations, P 0_DL , α DL , P 0_SL , and α SL may be the same as or different from P 0_DL , α DL , P 0_SL , and α SL used to control the transmission power of the sidelink feedback channel.

[0210] In operation S1330, the UE that determines the transmission power of the S-PSS, the S-SSS, and the PSBCH based on at least one of Equation 3, Equation 4, Equation 5, Equation 6, and the modification of Equation can transmit the S-SSB with the corresponding transmission power.

[0211] With Figure 13 differences, the operation in which the base station commands the transmission of the sidelink synchronization channel with the maximum transmission power can be omitted. In this case, operation S1315 in which the UE determines whether to transmit the sidelink synchronization channel with the maximum transmission power, and operations S1320 and S1325 performed based on the result of the determination can be omitted.

[0212] Figure 14 is a diagram illustrating an example of allocating a time axis resource for a sidelink feedback channel according to an embodiment of the disclosure.

[0213] In Figure 14 , the time axis resource of the PSFCH (sidelink feedback channel) starts from slot #0 and has a periodic interval of 4 slots (N=4). Thus, the time axis resource of the PSFCH (sidelink feedback channel) can exist in slot #0, slot #4, slot #8, slot #2, and slot #6. In addition, Figure 14 Assuming that K is 3 slots, this is a time relationship between the PSSCH transmitted by the sidelink TX UE (i.e., the PSSCH received by the sidelink RX UE) and the PSFCH that the sidelink RX UE needs to transmit. That is, within a time shorter than 3 slots, the sidelink RX UE cannot decode the PSSCH transmitted from the sidelink TX UE, prepare HARQ-ACK information and HARQ-NACK information, and transmit the PSFCH. Thus, as Figure 14 indicated, HARQ-ACK / NACK information associated with the PSSCH received by the sidelink RX UE in slots #0 and #1 can be transmitted in slot #4. HARQ-ACK / NACK information associated with the PSSCH received by the sidelink RX UE in slots #2, #3, #4, and #5 can be transmitted in slot #8. In addition, HARQ-ACK / NACK information associated with the PSSCH received by the sidelink RX UE in slots #6, #7, #8, and #9 can be transmitted in slot #2. Although it is assumed that k is 3 in the embodiment, the disclosure is not limited thereto.

[0214] As Figure 14 indicated, the sidelink feedback channel (PSFCH) that transmits HARQ-ACK / NACK information associated with the sidelink data channel (PSSCH) can not exist in every slot and can exist in some slots at a predetermined interval. That is,Figure 14 An example is shown where the PSSCH has a periodic interval of 4 time slots. A single sidelink RX UE can receive different PSSCHs from multiple sidelink TX UEs. In this case, the sidelink RX UE may need to send multiple sidelink feedback channels. Furthermore, a single sidelink RX UE can receive different PSSCHs from the same sidelink TX UE. In this case, the sidelink RX UE may need to send multiple sidelink feedback channels. Therefore, a method for determining the transmission power of multiple PSSCH transmissions may need to be considered.

[0215] Figure 15 This is a flowchart illustrating an example of a transmission power determination method when a single sidelink RX UE transmits multiple sidelink feedback channels according to an embodiment of the present disclosure.

[0216] If a single sidelink RX UE transmits a single sidelink feedback channel, the transmission power of the PSFCH can be determined based on Equation 7 below.

[0217] Equation 7

[0218] P PSFCH =min{P CMAX 10log 10 (2 μ ·M)+P 0_PSFCH +α PSFCH ·PL}[dBm]

[0219] In Equation 7, if the size of the frequency block used to transmit a single PSFCH is 1, then M can be omitted (i.e., M = 1). Furthermore, in Equation 7, the path loss value (PL) can be the downlink path loss value. In this case, as... Figure 10 to Figure 13 As shown, the sidelink RX UE that needs to send PSFCH can estimate the downlink path loss value based on the DMRS of SSB, SSB, and PBCH or the CSI-RS sent by the base station. In this case, P 0_PSFCH It can be P 0_DL_PSFCH , and α PSFCH It can be α DL_PSFCH .

[0220] If the sidelink RX UE that needs to send PSFCH is outside the base station's coverage area, then α is pre-configured in Equation 7. PSFCH =0 (pre-configured). If the sidelink RX UE is outside the base station's coverage area, it can be configured by min{P}. CMAX 10log 10 (2 μ ·M)+P 0_PSFCHAs another example, if the sidelink RX UE exists outside of a coverage area of the base station, the transmission power of the PSFCH can be fixed to a predetermined value, instead of being determined based on the equation (e.g., Equation 7).

[0221] According to an embodiment, Equation 7 can be an equation associated with a method of determining the PSFCH transmission power when a single sidelink RX UE transmits a single PSFCH. As Figure 14 indicated, a single sidelink RX UE can transmit multiple PSFCHs, and thus, a method of determining the PSFCH transmission power for this case needs to be considered.

[0222] It is assumed that the number of PSFCHs that a single UE can transmit at the same time is N (although N denotes a periodic interval of PSFCH time resources in Figure 13 , N denotes the number of PSFCHs that a single UE can transmit at the same time in Figure 15 ). In this case, N can be different depending on the capability of the sidelink UE. For example, sidelink UE-1 can have N = 4, sidelink UE-2 can have N = 2, and sidelink UE-3 can have N = 1. If the sidelink UE exists in a coverage area of the base station (in-coverage), the capability of the sidelink UE can be reported to the base station. By considering the capability of the UE, the base station can perform resource allocation for the sidelink feedback channel based on the capability (i.e., can configure a periodic interval of PSFCH time resources based on the capability). When the sidelink TX UE and the sidelink RX UE establish a PC5 RRC connection, they can exchange information associated with the capability.

[0223] N can be the maximum number of PSFCHs that a sidelink UE can transmit at the same time, and the UE can use a smaller number than N when actually performing PSFCH transmission. For example, if N = 4, the sidelink UE can transmit 2 PSFCHs at the same time, where 2 is less than 4.

[0224] As Figure 15 indicated, in operation S1510, the sidelink RX UE that is to transmit the PSFCH can receive, from the base station, parameters associated with the PSFCH transmission power configuration via system information and / or RRC configuration. In this case, the parameters associated with the PSFCH transmission power configuration can be at least one of P0, α, μ, M, and Δ values and information associated with a link to which a path loss value needs to be applied, as Figure 10 to Figure 13The sidelink RX UE receiving the parameters can determine the number of PSSCHs required for PSFCH transmission in operation S1515. In this case, the PSFCH transmission resource can be determined based on the PSSCH frequency resource (e.g., the starting subchannel index at the reception start of the PSSCH) and the PSSCH time resource (e.g., the slot index at which the PSSCH is received). If a single PSSCH requiring PSFCH transmission is received, the sidelink RX UE can determine the PSFCH transmission power based on Equation 7 in operation S1520. If multiple PSSCHs requiring PSFCH transmission are received, and PSFCH transmission needs to be performed at the same time, the sidelink RX UE can determine the number of PSFCHs to be simultaneously transmitted in operation S1525. In this case, N indicating the maximum number of PSFCHs that the UE can simultaneously transmit can be different depending on the capability of the UE. The number of PSFCHs that the sidelink RX UE needs to simultaneously transmit can be configured for each resource pool. For example, assuming that the number of PSFCHs that the sidelink RX UE needs to simultaneously transmit is L, L ≤ N needs to be satisfied. Specifically, if the sidelink RX UE having a capability of N = 4, N = 3, and N = 2 needs to transmit PSFCHs in a single resource pool, respectively, L configured for the corresponding resource pool can be L = 2. That is, based on the sidelink UE having the lowest capability in consideration of the capability of the sidelink RX UE, L can be configured for the resource pool supporting PSFCH transmission.

[0225] As described above, if L (L ≤ N) is configured for the resource pool, the sidelink RX UE can need to transmit a number of PSFCHs less than N at the time point of performing PSFCH transmission. As another example, the sidelink RX UE can need to transmit a number of PSFCHs less than N at the time point of performing PSFCH transmission due to a shortage of PSFCH resources. In this case, L PSFCHs are selected from among N candidate PSFCHs to be transmitted. For example, as described above, the PSSCH resource can be in a relationship mapped to the PSFCH resource. Each sidelink data transmitted via the PSSCH can have a priority value delivered from a higher layer, and thus the sidelink RX UE can select L PSFCHs (in this case, L is a value greater than or equal to 1) that the UE actually wants to transmit from among N candidate PSFCHs based on the priority.

[0226] As described above, the sidelink RX UE selecting the number of PSFCHs to be simultaneously transmitted based on the priority and / or the number of PSFCH resources at the time point of performing transmission in operation S1530 can set the PSFCH transmission power according to at least one of the following methods.

[0227] Method 1) determining a PSFCH transmission power based on a number (L) of PSFCHs to be simultaneously transmitted.

[0228] Method 1) can be a method of determining a transmission power of L PSFCHs based on the following Equation 8.

[0229] [Equation 8]

[0230] P PSFCH = min{P CMAX，L , 10 log 10 (2 μ · M · L) + P 0_PSFCH + α PSFCH · PL} [dBm]

[0231] In Equation 8, P CMAX，L may be a maximum transmission power value allowed for a UE when the UE simultaneously transmits L PSFCHs. Generally, P CMAX may be a maximum transmission power value set for the UE regardless of a number of PSFCHs to be transmitted, and thus, it can not be preferable that the maximum transmission power value of the UE varies depending on the number of PSFCHs to be simultaneously transmitted. Thus, Equation 8 can not be suitable. As another example, Equation 9 can be considered.

[0232] [Equation 9]

[0233] P PSFCH = min{P CMAX , 10 log 10 (2 μ · M · L) + P 0_PSFCH + α PSFCH · PL} [dBm]

[0234] In Equation 9, a sidelink RX UE that simultaneously transmits L PSFCHs can calculate a transmission power of the L PSFCHs based on Z_dB = 10 log 10 (2 μ · M · L) + P 0_PSFCH + α PSFCH · PL. If Z_dB < P CMAX , the Z_dB value can be used as the transmission power of the L PSFCHs. Otherwise, if Z_dB ≥ P CMAX , the UE can uniformly scale down the transmission power of the L PSFCHs so that the Z_dB value is less than or equal to P CMAX .

[0235] Specifically, a PSFCH transmission power value set for transmitting a single PSFCH can be defined as X_dB = 10 log 10 (2μ • M) + P 0_PSFCH + α PSFCH • PL, and can be expressed as X = 10^(X_dB / 10). That is, X_dB, which is scaled in dB, is modified to X in the linear domain. In this case, Y = L•X is defined, which is L (i.e., the transmission of L PSFCHs) multiplied by X (the PSFCH transmission power value, which is set for transmitting a single PSFCH and expressed in the linear domain). Y in the linear domain can be modified to Y_dB = 10log 10 (Y) = 10log 10 (L•X) = 10log 10 (L) + 10log 10 (X) = 10log 10 (L) + X_dB, which is a dB value. In this case, X_dB is defined as X_dB = 10log 10 (2 μ • M) + P 0_PSFCH + α PSFCH • PL, and thus Y_dB can be expressed as 10log 10 (L) + 10log 10 (2 μ • M) + P 0_PSFCH + α PSFCH • PL, which is the same as the pre-defined Z_dB.

[0236] The above scaling down can be performed in the linear domain, instead of in the dB domain. That is, Z_dB can be modified to a value in the linear domain (Z = 10^(X_dB / 10)), and Pcmax can be modified to a value in the linear domain (10^(Pcmax / 10)). In this case, scaling can be performed by β so that 10^(Pcmax / 10) ≤ β•Z is satisfied, and β has a value in the range of 0 ≤ β ≤ 1.

[0237] Method 2) determines the transmission power of a single PSFCH, and increases the transmission power based on the number of PSFCHs to be simultaneously transmitted.

[0238] Method 2) can be similar to Method 1), but can be different as follows. Equation 10 can be considered to transmit N PSFCHs.

[0239] [Equation 10]

[0240] P PSFCH-1 = min{P CMAX , 10log10(2 μ_1 • M1) + P 0_PSFCH-1 + α PSFCH-1 • PL1} [dBm]

[0241] P PSFCH-2 = min{P CMAX , 10log 10 (2 μ_2 ·M2)+P 0_PSFCH-2 +α PSFCH-2 ·PL2}[dBm]

[0242] …

[0243] P PSFCH-N = min{P CMAX , 10log 10 (2 μ_N ·M N )+P 0_PSFCH-N +α PSFCH-N ·PL N}[dBm]

[0244] In Equation 10, P PSFCH-N denotes the transmission power of the Nth PSFCH. μ_N, M N , P 0_PSFCH-N , α PSFCH-N , and PL N denote the subcarrier spacing, the size of the allocated frequency block, P0, α, and the path loss value of the Nth PSFCH, respectively. If N PSFCHs are transmitted to different sidelink TX UEs, at least one of the above parameters can be different. That is, a first PSFCH and a second PSFCH can be transmitted to a sidelink transmission UE-1, and a third PSFCH can be transmitted to a sidelink transmission UE-2. In this case, the transmission power value of each PSFCH can be different from each other. Further, if a plurality of PSFCHs are transmitted to the same TX UE, at least one of the above parameters can have a different value according to the configuration by the base station, etc.

[0245] If the sidelink RX UE needs to simultaneously transmit L PSFCHs among N PSFCHs to the same TX UE or different TX UEs, the transmission power value of each PSFCH needs to be set to the same value. The reason is that if the transmission power values of the PSFCHs transmitted on the same symbol are different, interference can occur to the transmitted PSFCHs due to the imbalance of the transmission power values of the PSFCHs. For this, at least one of the following operations can be considered.

[0246] Method 2-A) The transmission power value of each of the L PSFCHs is calculated based on Equation 10, and scaling down or up can be performed based on the transmission power value of the PSFCH having the highest priority, such that the transmission power values of the remaining PSFCHs are the same. In this case, as described above, the operation associated with scaling down or up can be performed in a linear domain.

[0247] Method 2-B) The transmission power value of each of the L PSFCHs is calculated based on Equation 10, and unlike Method 2-A), scaling up can be performed based on the PSFCH having the highest transmission power value (regardless of priority), such that the transmission power values of the remaining PSFCHs are the same. Alternatively, scaling down can be performed based on the PSFCH having the lowest transmission power value, such that the transmission power values of the remaining PSFCHs are the same. In this case, as described above, the operation associated with scaling down or up can be performed in a linear domain.

[0248] If the transmission power value of each of the L PSFCHs to be simultaneously transmitted is calculated according to the above-described Methods 2-A and 2-B, and the transmission power value of each of the L PSFCHs remains the same, the sidelink RX UE can calculate the transmission power value of the L PSFCHs based on Equation 9. In this case, as described above, the transmission power value of the L PSFCHs can be calculated based on Z_dB = 10 log 10 (2 μ ·M·L)+P 0_PSFCH +α PSFCH ·PL. If Z_dB < P CMAX , the Z_dB value can be used as the transmission power of the L PSFCHs. Otherwise, if Z_dB ≥ P CMAX , the UE can perform additional scaling down such that the transmission power values of the L PSFCHs remain the same and the Z_dB value is less than or equal to P CMAX .

[0249] In operation S1535, the UE that determines the PSFCH transmission power based on at least one of the above-described methods for setting the PSFCH transmission power can transmit the PSFCH using the corresponding transmission power.

[0250] Based on the above discussion, the disclosure relates to a method and apparatus for controlling transmission power of a sidelink synchronization channel in a wireless communication system. The method for controlling transmission power of a sidelink synchronization channel in a wireless communication system according to an embodiment can include an operation of receiving a parameter associated with control of transmission power of a sidelink synchronization channel from a base station, an operation of determining a transmission power value of the sidelink synchronization channel based on the parameter, and an operation of transmitting the sidelink synchronization channel based on the set transmission power.

[0251] Further, the disclosure relates to a method and apparatus for controlling transmission power of a sidelink feedback channel in a wireless communication system. The method for controlling transmission power of a sidelink feedback channel in a wireless communication system according to an embodiment can include an operation of receiving, from a base station, a parameter associated with control of transmission power of a sidelink feedback channel, an operation of determining a transmission power value of the sidelink feedback channel based on the parameter, and an operation of transmitting the sidelink feedback channel based on the set transmission power.

[0252] Figure 16 is a block diagram illustrating a structure of a transmission (TX) UE according to an embodiment of the disclosure.

[0253] As Figure 16 indicated, the TX UE of the disclosure can include a transceiver 1610, a memory 1620, and a processor 1630. The processor 1630, the transceiver 1610, and the memory 1620 of the TX UE can operate according to the above-described communication method of the TX UE. However, the elements of the TX UE are not limited to the above-described examples. For example, the TX UE can include more or less elements than the above-described elements. Further, the processor 1630, the transceiver 1610, and the memory 1620 can be implemented as a single chip. Further, the processor 1630 can include one or more processors.

[0254] The transceiver 1610 is a general name of a receiver and a transmitter of the TX UE, and can perform transmission or reception of a signal together with a base station. The transmitted or received signal can include control information and data. To this end, the transceiver 1610 can include an RF transmitter that up-converts and amplifies a frequency of a transmitted signal, an RF receiver that amplifies a received signal and down-converts a frequency of the signal, and the like. This is merely an example of the transceiver 1610, and the elements of the transceiver 1610 are not limited to the RF transmitter and the RF receiver.

[0255] Further, the transceiver 1610 can receive a signal via a wireless channel and output it to the processor 1630, and can transmit a signal output from the processor 1630 via a wireless channel.

[0256] The memory 1620 can store programs and data required when the TX UE operates. Further, the memory 1620 can store control information or data included in a signal obtained by the TX UE. The memory 1620 can be implemented as a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, a DVD, and the like, or a combination of storage media.

[0257] The processor 1630 can control a series of processes so that the TX UE operates according to the above-described embodiments of the disclosure. For example, according to the embodiments of the disclosure, the processor 1630 can control the elements of the TX UE in order to implement the method of setting the transmission power of the sidelink synchronization channel and the sidelink feedback channel. For example, the transceiver 1610 can receive a data signal including a control signal, and the processor 1630 can determine a reception result associated with the data signal.

[0258] Figure 17 is a block diagram illustrating a structure of a reception (RX) UE according to an embodiment of the disclosure.

[0259] As Figure 17 indicated, the RX UE of the disclosure can include a transceiver 1710, a memory 1720, and a processor 1730. The processor 1730, the transceiver 1710, and the memory 1720 of the RX UE can operate according to the above-described communication method of the RX UE. However, the elements of the RX UE are not limited to the above-described examples. For example, the RX UE can include more or less elements than the above-described elements. Also, the processor 1730, the transceiver 1710, and the memory 1720 can be implemented as a single chip. Also, the processor 1730 can include at least one processor.

[0260] The transceiver 1710 is a general name of a receiver and a transmitter of the RX UE, and can perform transmission or reception of a signal together with a base station. The transmitted or received signal can include control information and data. To this end, the transceiver 1710 can include an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, an RF receiver that amplifies a received signal and down-converts the frequency of the signal, and the like. This is merely an example of the transceiver 1710, and the elements of the transceiver 1710 are not limited to the RF transmitter and the RF receiver.

[0261] Also, the transceiver 1710 can receive a signal via a wireless channel and output it to the processor 1730, and can transmit a signal output from the processor 1730 via a wireless channel.

[0262] The memory 1720 can store programs and data required when the RX UE operates. Also, the memory 1720 can store control information or data included in a signal obtained by the RX UE. The memory 1720 can be implemented as a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, a DVD, and the like, or a combination of storage media.

[0263] The processor 1730 can control a series of processes so that the RX UE operates according to the above-described embodiments of the disclosure. For example, according to the embodiments of the disclosure, the processor 1730 can control the elements of the RX UE in order to implement the method of setting the transmission power of the sidelink synchronization channel and the sidelink feedback channel. For example, the transceiver 1710 can receive a data signal including a control signal, and the processor 1730 can determine a reception result associated with the data signal.

[0264] Figure 18 is a flowchart illustrating an example of a transmission power determination method when a single sidelink RX UE transmits a plurality of sidelink feedback channels according to an embodiment of the disclosure.

[0265] If the single sidelink RX UE transmits the k-th sidelink feedback channel at the transmission point i, the transmission power (P PSFCH，k (i)) of the PSFCH can be determined based on Equation 11 below.

[0266]

Equation 11

[0267] P PSFCH，k (i) = min{P CMAX , 10 log 10 (2 μ ·M) + P 0_PSFCH + α PSFCH ·PL} [dBm]

[0268] In Equation 11, if the size of the frequency block used to transmit a single PSFCH is 1, M can be omitted (i.e., M = 1). Also, in Equation 11, the path loss value (PL) can be a downlink path loss value. In this case, as shown in Equation 12 below, the sidelink RX UE that is to transmit the PSFCH can estimate the downlink path loss value based on an SSB, a DMRS of a PBCH, or a CSI-RS transmitted by the base station. Figure 10 to Figure 13 0_PSFCH may be P 0_DL_PSFCH , and α PSFCH may be α DL_PSFCH .

[0269] If the sidelink RX UE that transmits the PSFCH is outside the coverage area of the base station, α PSFCH = 1 (preconfigured) in Equation 11. That is, if the sidelink RX UE is outside the coverage area of the base station, the transmission power of the PSFCH can be determined by min{P CMAX , 10 log 10 (2 μ ·M) + P 0_PSFCH ​may be fixed to a predetermined value instead of being determined based on the equation (e.g., Equation 11). As another example, P 0_PSFCH is information set by a higher signal, but if the higher signal does not exist, P PSFCH，k (i) = P CMAX or P PSFCH (i) = P CMAX . P PSFCH (i) is the transmission power of the PSFCH when a single sidelink feedback channel or multiple sidelink feedback channels is transmitted at transmission point i, α PSFCH is information set by a higher signal, but if the higher signal does not exist, α PSFCH = 1. μ is a value indicating a subcarrier spacing of a sidelink channel. There is a relationship: μ = 0 when 15 kHz, μ = 1 when 30 kHz, μ = 2 when 60 kHz, and μ = 3 when 120 kHz, and this relationship can be expressed as 15 · 2 μ kHz subcarrier spacing based on μ.

[0270] As Figure 18As illustrated, in operation S1810, the UE can receive higher signal configuration information related to the PSFCH transmission, and can receive the PSSCH in operation S1820, and can determine the PSFCH transmission resource based on the PSSCH frequency resource (e.g., the starting subchannel index at the reception start of the PSSCH) and the PSSCH time resource (e.g., the slot index at which the PSSCH is received). Further, if the UE receives only a single PSSCH, the UE can transmit a single PSFCH. If the UE receives a plurality of PSSCHs, the UE can transmit a plurality of PSFCHs. If the number of PFSCHs that the UE can transmit at the same time is B, the value of B can be configured by a UE-common higher signal or a UE-specific higher signal, or can be determined based on the UE capability reported by the RX UE. In operation S1830, if the number of PSFCHs that the RX UE is scheduled to transmit at the same time at a predetermined point i is A, the UE can compare A and B in order to determine the number of PSFCHs to be transmitted. If A is greater than B, since the RX UE is capable of transmitting as many PSFCHs as the maximum number (B) of PSFCHs that can be transmitted at the same time, in operation S1840, the RX UE can select B PSFCHs in order of priority one by one and determine to transmit B PSFCHs. The priority information can be indicated by the PSCCH that schedules the PSFCH, or can be determined by the resource location or broadcast information. Alternatively, in the case where it is necessary to select a PSFCH from among PSFCHs having the same priority, the RX UE can randomly select a PSFCH, or (from the perspective of frequency) can select a PSFCH having a low index or a high index. If the number of PSFCHs that the RX UE is scheduled to transmit at the same time at a predetermined point i is A, and A is less than or equal to B, the RX UE can determine to transmit min(A, B) PSFCHs at the predetermined point i. Before transmitting the determined number of PSFCHs, the RX UE can determine the transmission power allocated for each PSFCH based on Equation 11.

[0271] If the total transmission power (P total ) allocated for the min(A, B) PSFCHs is greater than the maximum transmission power (P CMAX ) of the RX UE, the RX UE can not be able to transmit the determined number of PSFCHs at the transmission power determined based on Equation 11. Accordingly, in operation S1860, the UE can transmit the PSFCHs with power within the maximum transmission power (P CMAX ) of the RX UE according to at least one of the following two methods.

[0272] • Method 18-1: Perform additional transmission power reduction (reduced transmission power control) for each of the min(A, B) PSFCHs

[0273] • Method 18-2: Control the number of simultaneously transmitted PSFCHs (C) such that C is less than min(A, B) (C < min(A, B))

[0274] The above total transmission power (P total ) can be the sum of the transmission power allocated for each PSFCH, and can be defined as

[0275] In particular, according to method 18-1, in the case where the total transmission power (P total ) for PSFCH transmission by the RX UE exceeds P CMAX (i.e., if the expression P total > P CMAX ), the transmission power P PSFCH,k (i) of the kth sidelink feedback channel if transmitted by a single sidelink RX UE at transmission point i can be determined based on the following Equation 12.

[0276]

Equation 12

[0277]

[0278] Alternatively, the RX UE can re-allocate the transmission power of the sidelink feedback channels such that the transmission power of the kth sidelink feedback channel at transmission point i is less than or equal to the maximum transmission power of the RX UE. Thus, method 18-1 can provide a method in which the RX UE re-allocates the transmission power for each PSFCH uniformly such that the total PSFCH transmission power is less than or equal to the maximum transmission power of the UE.

[0279] In particular, according to method 18-2, if the total transmission power (P total ) for PSFCH transmission by the RX UE exceeds P CMAX (i.e., if the expression P total > P CMAX), the RX UE can transmit C PSFCHs according to the lowest (or highest) priority information value indicated by SCI format (or PSSCH) related to min(A, B) PSFCHs to be transmitted at the transmission point i. In this case, C is the maximum value among C values satisfying Equation 13 below. Accordingly, as described in Method 18-1, Method 18-2 can re-allocate the transmission power for each PSFCH, but the RX UE can determine the transmission power of some PSFCHs to be 0 and can maintain the transmission power of the remaining PSFCHs so that the total PSFCH transmission power becomes less than or equal to the maximum transmission power. Accordingly, in the case of PSFCHs whose transmission power is determined to be 0, the UE can not transmit the corresponding PSFCH.

[0280] [Equation 13]

[0281]

[0282] As Figure 18 indicated, according to Method 18-1 or 18-2, the RX UE can determine the PSFCHs to be transmitted at the predetermined point i and the transmission power of the PSFCHs, considering the maximum transmission power, and can transmit the PSFCHs in operation S1870. Further, if the total transmission power (P total ) allocated for the min(A, B) PSFCHs of the RX UE is less than or equal to the maximum transmission power (P CMAX ) of the RX UE, the UE can transmit the PSFCHs at the predetermined point i using the transmission power determined based on Equation 11 in operation S1870.

[0283] According to Figure 18 an embodiment, by sequentially considering the maximum number of PSFCHs that the RX UE can transmit at the predetermined point i and the PSFCH maximum transmission power, the RX UE can transmit the PSFCHs associated with the PSCCH / PSSCH.

[0284] Depending on the embodiment, Method 18-1 and Method 18-2 can be combined and executed, and the RX UE can determine the transmission power of each PSFCH. For example, if the RX UE can transmit not all of the determined PSFCHs with the transmission power determined based on Equation 11, since the total transmission power (P totalIf the amount of power is greater than the maximum transmission power of the RX UE, the RX UE can adjust the number of PSFCHs to be transmitted simultaneously as described in methods 18-1 and 18-2. For example, the RX UE can identify C PSFCHs based on the lowest priority value (or highest priority value) indicated by the SCI format (or PSSCH) associated with the PSFCHs to be transmitted at transmission point i. In this case, C can be the maximum number of PSFCHs such that the total transmission power allocated to the PSFCHs is less than or equal to the maximum transmission power of the RX UE. The RX UE can determine to transmit C or more PSFCHs simultaneously. In this case, the RX UE can determine the transmission power of each PSFCH to be transmitted simultaneously as the minimum value between the transmission power determined by uniformly allocating the RX UE's maximum transmission power based on the number of PSFCHs to be transmitted simultaneously and the predetermined transmission power of each PSFCH (e.g., the transmission power of each PSFCH allocated in the initial stage or the transmission power determined based on Equation 11). For example, min(A,B) in Equation 12 can be replaced by RX, where the UE determines the number of PSFCHs to be transmitted simultaneously. Therefore, the minimum value between the transmission power determined above and the predetermined transmission power of each PSFCH (e.g., the transmission power of each PSFCH allocated in the initial phase or the transmission power determined based on Equation 11) can be determined as the transmission power of each PSFCH to be transmitted simultaneously.

[0285] Figure 19 This is a flowchart illustrating an example of a transmission power determination method when a single sidelink RX UE transmits multiple sidelink feedback channels according to an embodiment of the present disclosure.

[0286] exist Figure 18 In this context, the maximum number (B) of PFSCHs that an RX UE can simultaneously transmit at a predetermined point i is a value set by the UE's common higher signal or UE-specific higher signal, or determined based on the UE capabilities reported by the RX UE. Figure 19 In this context, the maximum number (B) of PFSCHs that a UE can simultaneously transmit at a predetermined point i is based on the maximum power (P) that the UE can transmit at point i. CMAX The value is determined by the quantity. Therefore, Figure 18 The value of B in the equation is determined based on higher signal strength or UE capabilities, but... Figure 19 In this context, B is the transmission power allocated to each PSFCH and the UE's maximum transmission power P. CMAX A definite value.

[0287] According to an embodiment, if the RX UE sends A PSFCHs at a predetermined PSFCH transmission point i, then the RX UE can send min(A,B) PSFCHs that satisfy all of the following conditions.

[0288] • Condition 19-1: The min(A, B) PSFCHs can be determined based on priority information indicated by a SCI format or a PSSCH related to the PSFCH. For example, a PSFCH indicated by a SCI format having a low priority value can be preferentially transmitted.

[0289] • Condition 19-2: B can be a maximum value satisfying the following Equation 14. Alternatively, B can be a value determined based on Equation 15.

[0290] [Equation 14]

[0291]

[0292] [Equation 15]

[0293]

[0294] As an example of Condition 19-1, in a case where PSFCH-1, PSFCH-2, and PSFCH-3 are scheduled and their priority values are 0, 1, and 2, respectively, if the maximum number of PSFCHs that the RX UE can simultaneously transmit is 2, the RX UE can simultaneously transmit PSFCH-1 and PSFCH-2 having low priority values, and can not transmit PSFCH-3.

[0295] Figure 19 FIG. 19 is a flowchart illustrating a simultaneous PSFCH transmission procedure of an RX UE according to an embodiment, considering Condition 19-1 and Condition 19-2. In Figure 19 In the above-described embodiment, although P i or P j is determined based on Equation 11, and can consider a value converted into mW, not dBm. The relationship between dBm and mW can be defined by Equation 16.

[0296] [Equation 16]

[0297] dBm = 10 log 10 (mW), mW = 10 mW / 10

[0298] In operation S1915, it can be determined whether or not the priority value of the PSCCH is less than the priority value of the PSSCH, as described in Equation 14. Figure 15 to Figure 18The higher signal described in the middle configures the UE with PSFCH-related information, and in operation S1920, the UE can receive a single PSSCH or multiple PSSCHs. In operation S1925, the UE can sequentially select PSFCHs having high priority based on the priority values of the received PSSCHs. If it is assumed that PSFCHs having high priority at a predetermined PSFCH transmission point i are PSFCH-1, PSFCH-2, PSFCH-3,..., PSFCH-k,..., the RX UE can sequentially add the PSFCHs one by one to PSFCH_set, which is a set of PSFCHs to be simultaneously transmitted, within a range not exceeding the maximum transmission power P CMAX (i) of the UE. For example, if it is assumed that at the PSFCH transmission point i, the transmission power of PSFCH-1 is P PSFCH,1 (i), the transmission power of PSFCH-2 is P PSFCH,2 (i), the transmission power of PSFCH-3 is P PSFCH,3 (i), the transmission power of PSFCH-k is P PSFCH,k (i),..., etc., PSFCH transmission can be performed as follows based on

Pseudo code 1

Pseudo code 1

[0299]

Pseudo code 1 begins

[0300]

[0301]

Pseudo code 1 ends

[0302] In

Pseudo code 1

Pseudo code 1

[0303] In Figure 19 , B is a value determined based on the transmission power allocated for each PSFCH and the maximum transmission power P CMAX of the UE. In

Pseudo code 1

Pseudo code 1

[0304] As another example, in addition to

Pseudo code 1

[0305] The method disclosed in the claims and / or the method according to the various embodiments described in the specification of the disclosure can be implemented by hardware, software, or a combination of hardware and software.

[0306] When the method is implemented by software, a computer-readable storage medium for storing one or more programs (software modules) can be provided. The one or more programs stored in the computer-readable storage medium can be configured to be executed by one or more processors within the electronic device. At least one program can include instructions that cause the electronic device to perform the methods according to various embodiments of the disclosure defined by the appended claims and / or disclosed herein.

[0307] The programs (software modules or software) can be stored in non-volatile memories including random access memories and flash memories, read-only memories (ROMs), electrically erasable programmable read-only memories (EEPROMs), magnetic disks storage devices, compact disc ROMs (CD-ROMs), digital versatile discs (DVDs), or other type of optical storage devices, or magnetic cassette. Alternatively, some or all of the programs can be stored in a memory that is detachable from the electronic device, such as a flash drive, and accessible via a communication network. Such memory can be accessible via an external port of the electronic device. Further, a separate storage device of the communication network can access the portable electronic device.

[0308] Further, the programs can be stored in an attachable storage device which can access the electronic device through a communication network such as the Internet, Intranet, Local Area Network (LAN), Wide Area Network (WAN), and Storage Area Network (SAN), or a combination thereof. Such a storage device can access the electronic device via an external port. Further, a separate storage device on the communication network can access the portable electronic device.

[0309] ​In this disclosure, the terms "computer program product" or "computer-readable medium" are generally used to refer to media such as memory, hard disks installed in hard disk drives, signals, etc. A "computer program product" or "computer-readable medium" is a unit provided for a method of configuring the transmission power of a sidelink synchronization channel and a sidelink feedback channel.

[0310] In the detailed embodiments described above, elements included in this disclosure are represented in a singular or plural form according to the presented embodiments. However, for ease of description, the singular or plural form is suitably chosen as presented, and this disclosure is not limited to elements expressed in a singular or plural form. Thus, an element represented in a plural form may also include a single element, or an element represented in a singular form may include multiple elements.

[0311] In the accompanying drawings describing the methods of this disclosure, the order described does not always correspond to the order in which the steps of each method are performed, and the order between the steps may be changed or the steps may be performed in parallel.

[0312] Alternatively, in the accompanying drawings describing the methods of this disclosure, some elements may be omitted and only some elements may be included without departing from the essential spirit and scope of this disclosure.

[0313] Furthermore, embodiments of this disclosure described and illustrated in the specification and drawings have been presented to readily explain the technical content of this disclosure and to aid in understanding it. These embodiments are not intended to limit the scope of this disclosure. Other variations based on the technical ideas of the embodiments will be apparent to those skilled in the art. Where necessary, the various embodiments can be combined without departing from the spirit of this disclosure. For example, one embodiment of this disclosure may be combined with portions of other embodiments. Moreover, based on the technical ideas of the embodiments, other variations of the above embodiments can be implemented in other systems (e.g., LTE, 5G, and NR systems).

Claims

1. A method of a first user equipment, UE, in a communication system, the method comprising: receiving, from a base station, configuration information associated with power control for transmission of a physical sidelink feedback channel, PSFCH; receiving a plurality of physical sidelink shared channels, PSSCHs, scheduled based on a plurality of sidelink control information, SCIs; identifying whether a number of PSFCHs scheduled as a response to receiving the plurality of PSSCHs is less than or equal to a maximum number of PSFCHs the first UE is capable of transmitting; based on identifying that the number of scheduled PSFCHs is less than or equal to the maximum number of PSFCHs, identifying at least one PSFCH to be transmitted simultaneously in an order of priority in a case where a value associated with a sum operation of a transmission power using a single PSFCH and the number of scheduled PSFCHs is greater than a maximum transmission power, wherein information on the priority is indicated by at least one SCI associated with the at least one PSFCH, wherein the number of the at least one PSFCH to be transmitted simultaneously is identified based on a maximum value satisfying a condition, and wherein the condition is satisfied in a case where the value associated with the sum operation of the transmission power using a single PSFCH and the maximum number of PSFCHs is less than or equal to the maximum transmission power; based on identifying that the number of scheduled PSFCHs is greater than the maximum number of PSFCHs, identifying at least one PSFCH to be transmitted simultaneously in an order of priority in a case where a value associated with a sum operation of a transmission power using a single PSFCH and the maximum number of PSFCHs is greater than a maximum transmission power, wherein the number of the at least one PSFCH to be transmitted simultaneously is identified based on a maximum value satisfying the condition; based on the number of the at least one PSFCH, identifying a first transmission power of the at least one PSFCH; and transmitting the at least one PSFCH based on the first transmission power. 2.The method of claim 1, further comprising: based on identifying that the number of scheduled PSFCHs is less than or equal to the maximum number of PSFCHs, identifying a second transmission power of the scheduled PSFCHs based on the configuration information in a case where a value associated with a sum operation of a transmission power using a single PSFCH and the number of scheduled PSFCHs is less than or equal to a maximum transmission power; and transmitting the scheduled PSFCHs based on the second transmission power. 3.The method of claim 1, further comprising: based on identifying that the number of scheduled PSFCHs is greater than the maximum number of PSFCHs, identifying a second transmission power of a PSFCH corresponding to the maximum number based on the configuration information in a case where a value associated with a sum operation of a transmission power using a single PSFCH and the maximum number of PSFCHs is less than or equal to a maximum transmission power; and transmitting the PSFCH based on the second transmission power. the configuration information includes at least one of a first value and a second value for identifying a transmission power of a single PSFCH.

4. The method of claim 1, wherein, 5.The method of claim 4, ​ wherein the transmission power of the single PSFCH is identified based on a first value, a second value, and a downlink path loss value, and wherein the downlink path loss value is based on a measurement associated with a signal received from a base station.

6. The method of claim 1, wherein, the first transmission power of the at least one PSFCH is identified based on the maximum transmission power and a number of the at least one PSFCH.

7. The method of claim 1, wherein, the first transmission power of the at least one PSFCH is set to a same value.

8. A first user equipment, UE, of a communication system, the first UE comprising: a transceiver; and a controller coupled with the transceiver and configured to: receive, from a base station, configuration information associated with power control for transmission of a physical sidelink feedback channel, PSFCH, receive a plurality of physical sidelink shared channels, PSSCHs, scheduled based on a plurality of sidelink control information, SCIs, identify whether a number of PSFCHs scheduled as a response to the reception of the plurality of PSSCHs is less than or equal to a maximum number of PSFCHs the first UE is capable of transmitting, based on identifying that the number of scheduled PSFCHs is less than or equal to the maximum number of PSFCHs, in a case where a value associated with a sum operation using a transmission power of a single PSFCH and the number of scheduled PSFCHs is greater than a maximum transmission power, identify at least one PSFCH to be transmitted simultaneously in an order of priority, wherein information about the priority is indicated by at least one SCI associated with the at least one PSFCH, wherein a number of the at least one PSFCH to be transmitted simultaneously is identified based on a maximum value satisfying a condition, and wherein the condition is satisfied in a case where the value associated with the sum operation using the transmission power of the single PSFCH and the maximum number of PSFCHs is less than or equal to the maximum transmission power; based on identifying that the number of scheduled PSFCHs is greater than the maximum number of PSFCHs, in a case where a value associated with a sum operation using a transmission power of a single PSFCH and the maximum number of PSFCHs is greater than a maximum transmission power, identify at least one PSFCH to be transmitted simultaneously in an order of priority, wherein a number of the at least one PSFCH to be transmitted simultaneously is identified based on a maximum value satisfying the condition, identify a first transmission power of the at least one PSFCH based on a number of the at least one PSFCH; and transmit the at least one PSFCH based on the first transmission power.

9. The first UE of claim 8, wherein, the controller is configured to: based on identifying that the number of scheduled PSFCHs is less than or equal to the maximum number of PSFCHs, identify a second transmission power of the scheduled PSFCHs based on the configuration information in a case where a value associated with a sum operation using a transmission power of a single PSFCH and the maximum number of PSFCHs is less than or equal to a maximum transmission power, and transmit the scheduled PSFCHs based on the second transmission power.

10. The first UE of claim 8, wherein, the controller is configured to: based on identifying that the number of scheduled PSFCHs is greater than the maximum number of PSFCHs, in a case in which a value associated with a summation operation of a transmission power using a single PSFCH and the maximum number of PSFCHs is less than or equal to a maximum transmission power, identifying a second transmission power corresponding to the maximum number of PSFCHs based on configuration information; and transmitting the PSFCH based on the second transmission power.

11. The first UE of claim 8, wherein, The configuration information includes at least one of a first value and a second value for identifying a transmission power of a single PSFCH.

12. The first UE of claim 11, wherein The transmission power of the single PSFCH is identified based on the first value, the second value, and a downlink path loss value, and wherein the downlink path loss value is based on a measurement associated with a signal received from a base station.

13. The first UE of claim 8, wherein, The first transmission power of the at least one PSFCH is identified based on the maximum transmission power and the number of the at least one PSFCH.

14. The first UE of claim 8, wherein, The first transmission power of the at least one PSFCH is set to the same value.

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