Method for sidelink relay and device therefor in wireless communication system

Abstract

A method performed by a UE, according to an embodiment of the present disclosure, comprises the steps of: determining candidate UEs related to a sidelink relay; and determining a relay UE from among the candidate UEs. The relay UE is a candidate UE most likely to be determined on the basis of fuzzy inference among the candidate UEs. The probability is determined on the basis of i) a first input variable and a second input variable related to each of the candidate UEs, and ii) a rule related to the fuzzy inference. The first input variable is related to a signal to interference plus noise ratio (SINR) of each of the candidate UEs, and the second input variable is related to the number of neighboring UEs within a transmission radius of each of the candidate UEs.

Description

Method for sidelink relay in a wireless communication system and device therefor

[0001] The present disclosure relates to a method for sidelink relay in a wireless communication system and a device therefor.

[0002] To meet the growing demand for wireless data traffic following the commercialization of 4G (4th generation) communication systems, efforts are being made to develop improved 5G (5th generation) communication systems, or pre-5G communication systems. For this reason, 5G communication systems, or pre-5G communication systems, are also referred to as "Beyond 4G Network" communication systems or "Post-LTE" systems. To achieve high data rates, 5G communication systems are being considered for implementation in ultra-high frequency (mmWave) bands, such as the 60 gigahertz (70 GHz) band. To mitigate the path loss of radio waves in ultra-high frequency bands and increase the transmission distance of radio waves, beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antenna, analog beam-forming, and large-scale antenna technologies are being discussed in 5G communication systems.In addition, to improve the network of the system, technologies such as evolved small cells, advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device communication (D2D), wireless backhaul, moving networks, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation are being developed in 5G communication systems. In addition, advanced coding modulation (ACM) methods such as Hybrid FSK and QAM Modulation (FQAM) and Sliding Window Superposition Coding (SWSC), and advanced access technologies such as Filter Bank Multi Carrier (FBMC), Non-Orthogonal Multiple Access (NOMA), and Sparse Code Multiple Access (SCMA) are being developed in 5G systems.

[0003] Sidelink (SL) refers to a communication method that establishes a direct link between user equipment (UE), allowing voice or data to be exchanged directly between terminals without going through a base station (BS). SL is being considered as a solution to address the burden on base stations due to rapidly increasing data traffic.

[0004] V2X (vehicle-to-everything) refers to a communication technology that exchanges information with other vehicles, pedestrians, and infrastructure-based objects through wired / wireless communication. V2X can be divided into four types: V2V (vehicle-to-vehicle), V2I (vehicle-to-infrastructure), V2N (vehicle-to-network), and V2P (vehicle-to-pedestrian). V2X communication can be provided through the PC5 interface and / or Uu interface.

[0005] Meanwhile, as more and more communication devices demand greater communication capacity, the need for improved mobile broadband communication compared to existing radio access technology (RAT) is emerging. Accordingly, communication systems that consider services or terminals sensitive to reliability and latency are being discussed. Next-generation wireless access technologies that consider improved mobile broadband communication, massive machine type communication (MTC), and ultra-reliable and low latency communication (URLLC) can be called new radio access technology (RAT) or new radio (NR). NR can also support vehicle-to-everything (V2X) communication.

[0006] For sidelink relay operation, a relay terminal is selected based on a list of candidate relay terminals. Conventional techniques do not define conditions for selecting a relay terminal, other than those that initiate relay terminal reselection (e.g., PC5 signal strength). In other words, one of the candidate terminals is randomly selected as the relay terminal. If a relay terminal is randomly selected without considering the communication environment, relay terminal-based communication performance may degrade.

[0007] The purpose of the present disclosure is to propose a method for determining an optimal candidate terminal as a relay terminal by taking into account the communication environment.

[0008] The technical problems to be achieved in the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0009] A method performed by a terminal according to one embodiment of the present disclosure includes the steps of determining candidate terminals associated with a sidelink relay and determining a relay UE among the candidate terminals. The relay UE is a candidate terminal having a highest probability determined based on fuzzy inference among the candidate terminals. The probability is determined based on i) a first input variable and a second input variable associated with each candidate terminal and ii) a rule associated with the fuzzy inference. The first input variable is characterized in that it is related to a signal to interference plus noise ratio (SINR) of each candidate terminal, and the second input variable is characterized in that it is related to the number of surrounding terminals within a transmission radius of each candidate terminal.

[0010] The first input variable may be determined based on i) the SINR, ii) an SINR threshold, iii) a largest SINR among the SINRs associated with the candidate terminals, and iv) a smallest SINR among the SINRs.

[0011] The above first input variable can be determined based on the following mathematical formula.

[0012] [Mathematical formula]

[0013]

[0014] is the first input variable, is the above SINR, is the SINR threshold, is the largest SINR above, is the smallest SINR above.

[0015] The second input variable may be determined based on i) the number of peripheral terminals, ii) the largest value among the numbers of peripheral terminals related to the candidate terminals, and iii) the smallest value among the numbers of peripheral terminals.

[0016] The above second input variable can be determined based on the following mathematical formula.

[0017] [Mathematical formula]

[0018]

[0019] is the second input variable, is the number of peripheral terminals, is the largest value among the numbers of the above peripheral terminals, is the smallest value among the numbers of the above peripheral terminals.

[0020] One of the first linguistic terms may be determined based on the first input variable. One of the second linguistic terms may be determined based on the second input variable.

[0021] Third language terms based on the first and second language terms can be defined by the above rules. The probability can be based on one of the third language terms.

[0022] The above SINR may be greater than the SINR threshold.

[0023] A terminal according to another embodiment of the present disclosure includes one or more transceivers, one or more processors, and one or more memories that store instructions for operations to be executed by the one or more processors and are connected to the one or more processors.

[0024] The above operations include the steps of determining candidate terminals associated with a sidelink relay and the step of determining a relay terminal (UE) among the candidate terminals. The relay UE is a candidate terminal having the highest probability determined based on fuzzy inference among the candidate terminals. The probability is determined based on i) a first input variable and a second input variable associated with each candidate terminal and ii) a rule associated with the fuzzy inference. The first input variable is characterized in that it is related to a signal to interference plus noise ratio (SINR) of each candidate terminal, and the second input variable is characterized in that it is related to the number of surrounding terminals within a transmission radius of each candidate terminal.

[0025] A device according to another embodiment of the present disclosure includes one or more memories and one or more processors connected to the one or more memories.

[0026] The one or more memories store instructions that cause the one or more processors to perform operations based on what is executed by the one or more processors.

[0027] The above operations include the steps of determining candidate terminals associated with a sidelink relay and the step of determining a relay terminal (UE) among the candidate terminals. The relay UE is a candidate terminal having the highest probability determined based on fuzzy inference among the candidate terminals. The probability is determined based on i) a first input variable and a second input variable associated with each candidate terminal and ii) a rule associated with the fuzzy inference. The first input variable is characterized in that it is related to a signal to interference plus noise ratio (SINR) of each candidate terminal, and the second input variable is characterized in that it is related to the number of surrounding terminals within a transmission radius of each candidate terminal.

[0028] In accordance with another embodiment of the present disclosure, one or more non-transitory computer-readable media store instructions, the instructions being executable by one or more processors, that cause the one or more processors to perform operations.

[0029] The above operations include the steps of determining candidate terminals associated with a sidelink relay and the step of determining a relay terminal (UE) among the candidate terminals. The relay UE is a candidate terminal having the highest probability determined based on fuzzy inference among the candidate terminals. The probability is determined based on i) a first input variable and a second input variable associated with each candidate terminal and ii) a rule associated with the fuzzy inference. The first input variable is characterized in that it is related to a signal to interference plus noise ratio (SINR) of each candidate terminal, and the second input variable is characterized in that it is related to the number of surrounding terminals within a transmission radius of each candidate terminal.

[0030] According to an embodiment of the present disclosure, among candidate terminals, the one with the highest probability, determined based on fuzzy inference, is selected as the relay terminal. Therefore, relay terminals can be intelligently selected in communication blind spots or edge areas with insufficient coverage, thereby maintaining communication stability and reliability. Optimizing relay terminal selection effectively optimizes network resource utilization, reduces congestion, improves data transmission efficiency, and reduces communication delay.

[0031] Additionally, power consumption of the terminal can be reduced by intelligently selecting the relay terminal.

[0032] Additionally, the optimal relay terminal can be selected in certain scenarios (e.g., scenarios where the position of terminals (i.e., vehicles) changes rapidly and continuously, such as on highways).

[0033] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned will be clearly understood by a person having ordinary skill in the art pertaining to the present disclosure from the description below.

[0034] The accompanying drawings, which are incorporated in and constitute a part of the detailed description to aid in the understanding of the present invention, provide embodiments of the present invention and, together with the detailed description, explain the technical features of the present invention.

[0035] FIG. 1 illustrates an example of a wireless network according to embodiments of the present disclosure.

[0036] FIG. 2 illustrates an example of a base station according to embodiments of the present disclosure.

[0037] FIG. 3 illustrates an example of a terminal according to embodiments of the present disclosure.

[0038] FIG. 4 is a diagram showing the basic structure of a time-frequency domain, which is a radio resource domain in which data or control channels are transmitted, in an NR system according to one embodiment of the present disclosure.

[0039] Figures 5 and 6 schematically illustrate the structure of a wireless frame applied to the present disclosure.

[0040] Figure 7 is a diagram illustrating side link communication performance.

[0041] FIG. 8 is a diagram for explaining the concept of cellular network-based D2D communication applied to the present disclosure.

[0042] FIG. 9 is a diagram illustrating a system according to one embodiment of the present disclosure.

[0043] FIG. 10 is a diagram for explaining a resource pool defined as a set of time and frequency resources used for transmission and reception of a side link according to one embodiment of the present disclosure.

[0044] FIG. 11 is a flowchart illustrating a scheduled resource allocation (mode 1) method in a side link according to one embodiment of the present disclosure.

[0045] FIG. 12 is a flowchart illustrating a UE autonomous resource allocation (mode 2) method in a sidelink according to one embodiment of the present disclosure.

[0046] Figure 13 illustrates two modes for wireless resource management.

[0047] Figure 14 is an example of a scenario related to UE to Network relay.

[0048] Figure 15 is another example of a scenario related to UE to Network relay.

[0049] Figure 16 is an example of a scenario related to UE to UE relay.

[0050] Figure 17 is another example of a scenario related to UE to UE relay.

[0051] FIG. 18 illustrates a flowchart related to selection of a relay terminal according to an embodiment of the present disclosure.

[0052] FIG. 19 illustrates a rule base of a fuzzy inference system related to relay terminal selection according to an embodiment of the present disclosure.

[0053] Figure 20 illustrates the structure of a fuzzy inference system according to an embodiment of the present disclosure.

[0054] FIG. 21 illustrates a membership function for a first input of a fuzzy inference system according to an embodiment of the present disclosure.

[0055] FIG. 22 illustrates a membership function for a second input of a fuzzy inference system according to an embodiment of the present disclosure.

[0056] FIG. 23 illustrates a membership function for the output of a fuzzy inference system according to an embodiment of the present disclosure.

[0057] FIG. 24 illustrates selection of a relay terminal and relay-based transmission according to an embodiment of the present disclosure.

[0058] FIG. 25 is a graph showing packet reception rates of relay-based transmission and direct transmission according to an embodiment of the present disclosure under certain transmission power conditions.

[0059] Figures 26 to 28 are graphs showing packet reception rates of relay-based transmission and direct transmission according to embodiments of the present disclosure at different densities.

[0060] FIG. 29 is a flowchart illustrating a method performed by a terminal according to one embodiment of the present disclosure.

[0061] In various embodiments of the present disclosure, " / " and "," should be interpreted as indicating "and / or". For example, "A / B" can mean "A and / or B". Furthermore, "A, B" can mean "A and / or B". Furthermore, "A / B / C" can mean "at least one of A, B, and / or C". Furthermore, "A, B, C" can mean "at least one of A, B, and / or C".

[0062] In various embodiments of the present disclosure, "or" should be interpreted as meaning "and / or." For example, "A or B" can include "only A," "only B," and / or "both A and B." In other words, "or" should be interpreted as meaning "additionally or alternatively."

[0063] The following technologies can be used in various wireless communication systems, such as CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), and SC-FDMA (single carrier frequency division multiple access). CDMA can be implemented with wireless technologies such as UTRA (universal terrestrial radio access) or CDMA2000. TDMA can be implemented with wireless technologies such as GSM (global system for mobile communications) / GPRS (general packet radio service) / EDGE (enhanced data rates for GSM evolution). OFDMA can be implemented with wireless technologies such as IEEE (Institute of Electrical and Electronics Engineers) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and E-UTRA (evolved UTRA). IEEE 802.16m is an evolution of IEEE 802.16e, providing backward compatibility with systems based on IEEE 802.16e. UTRA is part of UMTS (universal mobile telecommunications system). 3GPP (3rd generation partnership project) LTE (long term evolution) is a part of E-UMTS (evolved UMTS) that uses E-UTRA (evolved-UMTS terrestrial radio access), employing OFDMA in the downlink and SC-FDMA in the uplink.LTE-A (advanced) is an evolution of 3GPP LTE.

[0064] 5G NR, the successor to LTE-A, is a new clean-slate mobile communications system featuring high performance, low latency, and high availability. 5G NR can utilize all available spectrum resources, from low-frequency bands below 1 GHz, mid-frequency bands between 1 GHz and 10 GHz, and high-frequency (millimeter wave) bands above 24 GHz.

[0065] For clarity of explanation, the description will focus on LTE-A or 5G NR, but the technical ideas according to one embodiment of the present disclosure are not limited thereto.

[0066] To meet the growing demand for wireless data traffic following the commercialization of 4G communication systems, efforts are being made to develop improved 5G or pre-5G communication systems. For this reason, 5G or pre-5G communication systems are also referred to as "Beyond 4G Network" or "Post-LTE" systems. The 5G communication system specified by 3GPP is called the New Radio (NR) system. To achieve high data rates, 5G communication systems are being considered for implementation in ultra-high frequency (mmWave) bands (e.g., the 60 GHz band). To mitigate the path loss of radio waves in ultra-high frequency bands and increase the transmission distance of radio waves, beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antenna, analog beam-forming, and large-scale antenna technologies have been discussed and applied to NR systems in 5G communication systems.In addition, to improve the network of the system, technologies such as evolved small cells, advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device communication (D2D), wireless backhaul, moving networks, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation are being developed in 5G communication systems. In addition, advanced coding modulation (ACM) methods such as Hybrid FSK and QAM Modulation (FQAM) and Sliding Window Superposition Coding (SWSC), and advanced access technologies such as Filter Bank Multi Carrier (FBMC), Non-Orthogonal Multiple Access (NOMA), and Sparse Code Multiple Access (SCMA) are being developed in 5G systems.

[0067] Meanwhile, the Internet is evolving from a human-centric network where humans create and consume information to an Internet of Things (IoT) network where information is exchanged and processed between distributed components, such as objects. The Internet of Everything (IoE) is also emerging, combining IoT technologies with big data processing technologies, such as those connected to cloud servers. To implement the IoT, technological elements such as sensing technology, wireless and wired communication and network infrastructure, service interface technology, and security technology are required. Recently, research is being conducted on technologies such as sensor networks, Machine-to-Machine (M2M), and Machine-Type Communication (MTC) for connecting objects. In the IoT environment, intelligent IT (Internet Technology) services can be provided that collect and analyze data generated from connected objects to create new value for human life. IoT can be applied to areas such as smart homes, smart buildings, smart cities, smart or connected cars, smart grids, healthcare, smart appliances, and advanced medical services through the convergence and integration of existing IT (information technology) technologies with various industries.

[0068] Accordingly, various attempts are being made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, machine-to-machine (M2M), and machine-type communication (MTC) are being implemented using 5G communication techniques such as beamforming, MIMO, and array antennas. The application of cloud radio access networks (cloud RAN), a big data processing technology described above, is also an example of the convergence of 5G and IoT technologies.

[0069] Meanwhile, the new 5G communication, NR (New Radio access technology), is designed to allow various services to be freely multiplexed across time and frequency resources. Accordingly, waveforms, numerology, and reference signals can be dynamically or freely allocated according to the needs of each service. In wireless communication, optimized data transmission through measurement of channel quality and interference is crucial for providing optimal services to terminals. Accordingly, accurate channel status measurement is essential. However, unlike 4G communication, where channel and interference characteristics do not significantly vary depending on frequency resources, 5G channel and interference characteristics vary significantly depending on the service. Therefore, support for subsets at the Frequency Resource Group (FRG) level is required to enable separate measurement. Meanwhile, the types of services supported in the NR system can be categorized into eMBB (Enhanced mobile broadband), mMTC (massive Machine Type Communications) (mMTC), and URLLC (Ultra-Reliable and low-latency Communications). eMBB can be viewed as a service aimed at high-speed transmission of high-capacity data, mMTC aims at minimizing terminal power consumption and enabling multiple terminals to connect, and URLLC aims at high reliability and low latency. Different requirements may apply depending on the type of service applied to the terminal.

[0070] In this way, multiple services can be provided to users in a communication system, and in order to provide such multiple services to users, a method and a device using the same are required that can provide each service within the same time period according to its characteristics.

[0071] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings.

[0072] In describing the embodiments, descriptions of technical details that are well known in the technical field to which the present disclosure pertains and are not directly related to the present disclosure will be omitted. This is to more clearly convey the gist of the present disclosure without obscuring it by omitting unnecessary explanations.

[0073] For the same reason, some components in the attached drawings are exaggerated, omitted, or schematically depicted. Furthermore, the dimensions of each component do not entirely reflect its actual size. Identical or corresponding components in each drawing are assigned the same reference numbers.

[0074] The advantages and features of the present disclosure, and methods for achieving them, will become clearer with reference to the embodiments described below in detail with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms. These embodiments are provided solely to ensure that the disclosure is complete and to fully inform those skilled in the art of the scope of the disclosure, and the present disclosure is defined only by the scope of the claims. Like reference numerals designate like elements throughout the disclosure.

[0075] At this time, it will be understood that each block of the processing flow diagrams and combinations of the flow diagrams can be performed by computer program instructions. These computer program instructions can be installed in a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, so that the instructions executed by the processor of the computer or other programmable data processing equipment create a means for performing the functions described in the flow diagram block(s). These computer program instructions can also be stored in a computer-available or computer-readable memory that can direct a computer or other programmable data processing equipment to implement the functions in a specific manner, so that the instructions stored in the computer-available or computer-readable memory can also produce a manufactured item that includes an instruction means for performing the functions described in the flow diagram block(s). Since the computer program instructions may be installed on a computer or other programmable data processing device, a series of operational steps may be performed on the computer or other programmable data processing device to create a computer-executable process, and the instructions that cause the computer or other programmable data processing device to perform the steps for performing the functions described in the flowchart block(s) may also provide steps for performing the functions described in the flowchart block(s).

[0076] Additionally, each block may represent a module, segment, or portion of code that contains one or more executable instructions for performing a specific logical function(s). It should also be noted that in some alternative implementation examples, the functions described in the blocks may occur out of order. For example, two blocks depicted in succession may actually be executed substantially concurrently, or the blocks may sometimes be executed in reverse order, depending on their respective functions.

[0077] Here, the term '~ unit' used in the present embodiment means a software or hardware component such as an FPGA or ASIC, and the '~ unit' performs certain roles. However, the '~ unit' is not limited to software or hardware. The '~ unit' may be configured to be on an addressable storage medium and may be configured to regenerate one or more processors. Thus, as an example, the '~ unit' includes components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and '~ units' may be combined into a smaller number of components and '~ units' or further separated into additional components and '~ units'. In addition, the components and '~ units' may be implemented to regenerate one or more CPUs within a device or a secure multimedia card. Additionally, in the embodiment, '~bu' may include one or more processors.

[0078] Wireless communication systems are evolving from their initial voice-centric services to broadband wireless communication systems that provide high-speed, high-quality packet data services, such as 3GPP's HSPA (high speed Packet Access), LTE (long term evolution or E-UTRA (evolved universal terrestrial radio access)), LTE-Advanced (LTE-A), 3GPP2's HRPD (high rate packet data), UMB (ultra mobile broadband), and IEEE's 802.16e. In addition, communication standards for 5G or NR (new radio) are being developed as the 5th generation wireless communication system.

[0079] As a representative example of a broadband wireless communication system, the NR system adopts the OFDM (orthogonal frequency division multiplexing) method in both the downlink (DL) and uplink. More specifically, the CP-OFDM (cyclic-prefix OFDM) method is adopted in the downlink, and both the CP-OFDM and the DFT-S-OFDM (discrete Fourier transform spreading OFDM) method are adopted in the uplink. The uplink refers to a wireless link in which a user equipment (UE) or mobile station (MS) transmits data or control signals to a base station (gNode B or base station (BS)), and the downlink refers to a wireless link in which a base station transmits data or control signals to a UE. The above multiple access method typically distinguishes the data or control information of each user by allocating and operating the time-frequency resources to be used to transmit data or control information to each user so that they do not overlap, that is, so as to achieve orthogonality.

[0080] Wireless Network General

[0081] Figures 1 to 3 illustrate various embodiments implemented in the wireless communication system disclosed below and using orthogonal frequency division multiplexing (OFDM) or orthogonal frequency division multiple access.

[0082] Figures 1 through 3 do not imply any physical or structural limitations on the manner in which other embodiments may be implemented. Other embodiments of the present disclosure may be implemented in any suitably arranged communication system.

[0083] Figure 1 illustrates an example of a wireless network according to embodiments of the present disclosure. The embodiment of the wireless network illustrated in Figure 1 is for illustrative purposes only. Other embodiments of the wireless network 100 may be used without departing from the scope of the present disclosure.

[0084] As illustrated in FIG. 1, the wireless network may include gNB 101, gNB 102, and gNB 103. Additionally, gNB 101 may communicate with at least one network 103, for example, the Internet, a proprietary Internet Protocol (IP) network, or another data network.

[0085] A gNB 102 may provide wireless broadband access to a network 130 for a first plurality of user equipment (UE) within a coverage area 120 of the gNB 102. The first plurality of user equipment may include a user device 111 that may be located in a small business (SB), a user device 112 that may be located in an enterprise (E), a user device 113 that may be located in a WIFI hotspot (HS), a UE 114 that may be located in a first residence (R), a UE 115 that may be located in a second residence (R), a UE 115 that may be located in a mobile device (M), such as a cell phone, a wireless laptop, a wireless PDF, or the like.

[0086] The gNB 103 may provide wireless broadband access to the network 130 for a second plurality of UEs within a coverage area 125 of the gNB 103. The second plurality of UEs may include UE 115 and UE 116. In one embodiment, at least one of the gNBs 101-103 may communicate with each other or with the UEs 111-116 using 5G, LTE, LTE-A, WiMAX, WIFI, or other wireless communication technologies.

[0087] Depending on the network type, the term "base station" or "BS" can refer to any component (or collection of components) configured to provide wireless access to the network, such as a transmit point (TP), transmit-receive point (TRP), enhanced base station (eNodeB or eNB), 5G base station (gNB), macro cell, femtocell, WiFi access point (AP), or other radio-enabled device.

[0088] A base station may provide wireless access according to one or more wireless communication protocols, e.g., 5G 3GPP New Radio Interface / Access (NR), Long Term Evolution (LTE), LTE Advanced (LTE-A), High-Speed ​​Packet Access (HSPA), Wi-Fi 802.11a / b / g / n / ac, etc. For convenience, the terms "BS" and "TRP" are used interchangeably in this patent document to refer to a network infrastructure component that provides wireless access to a remote terminal. Additionally, depending on the network type, the term "user equipment" or "UE" may refer to any component, such as a "mobile station," "subscriber," "remote terminal," "wireless terminal," "reception point," or "user device."

[0089] For convenience, the terms "user equipment" and "UE" are used in this patent document to refer to remote wireless equipment that wirelessly accesses a BS, where the UE may be a mobile device (e.g., a mobile phone or a smart phone) or generally considered a stationary device (e.g., a desktop computer or a vending machine).

[0090] The dotted lines represent the approximate extents of coverage areas 120 and 125, which are depicted as roughly circular for illustration and illustrative purposes only. Coverage areas 120 and 125 associated with a gNB may have different shapes, including irregular shapes, depending on variations in the wireless environment associated with the configuration of the gNB and natural and human-made obstacles.

[0091] As described in more detail below, at least one of the UEs 111-116 may include circuitry, programming, or a combination thereof for reliable reception of data and control information in an advanced wireless communication system. In certain embodiments, at least one of the gNBs 101-103 may include circuitry, programming, or a combination thereof for efficient network control resource allocation in New Radio (NR) vehicle-to-everything (V2X) systems.

[0092] While FIG. 1 illustrates an example wireless network, various modifications may be made to FIG. 1 . For example, the wireless network may include any number of gNBs and any number of UEs in any suitable arrangement. Furthermore, gNB 101 may communicate directly with any number of UEs and provide these UEs with wireless broadband access to network 130. Similarly, each of gNBs 102-103 may communicate directly with network 130 and provide UEs with direct wireless broadband access to network 130. Furthermore, gNBs 101, 102, and / or 103 may provide access to other or additional external networks, such as an external telephone network or other types of data networks.

[0093] FIG. 2 illustrates an example of a gNB 102 according to embodiments of the present disclosure. The embodiment of the gNB 102 illustrated in FIG. 1 is for illustrative purposes only, and gNBs 101 and 103 of FIG. 1 may have the same or similar configurations. However, gNBs may be provided in various configurations, and FIG. 2 does not limit the scope of the disclosure to any particular implementation of a gNB.

[0094] As illustrated in FIG. 2, the gNB 102 may include multiple antennas 205a-205n, multiple radio frequency (RF) transceivers 210a-210n, transmit (TX) processing circuitry 215, and receive (RX) processing circuitry 220. The gNB 102 may also include a controller / processor 225, memory 230, and a backhaul or network interface (network IF) 235.

[0095] The RF transceivers 210a-210n can receive incoming RF signals, such as signals transmitted by UEs in the network 100, from the antennas 205a-205n. The RF transceivers 210a-210n can downconvert the incoming RF signals to generate intermediate frequency (IF) or baseband signals. The IF or baseband signals are transmitted to RX processing circuitry 220, which can generate baseband signals that are processed by filtering, decoding, and / or digitizing. The RX processing circuitry 220 can transmit the processed baseband signals to a controller / processor 225 for further processing.

[0096] TX processing circuitry 215 may receive analog or digital data (e.g., voice data, web data, email, interactive video game data) from controller / processor 225. TX processing circuitry 215 may encode, multiplex, and / or digitize the outgoing baseband data to generate processed baseband or IF signals.

[0097] The controller / processor 225 may include at least one processor or other processing device that controls the overall operation of the gNB 102. For example, the controller / processor 225 may control the reception of forward channel signals and the transmission of reverse channel signals by the RF transceivers 210a-210n, the RX processing circuitry 220, and the TX processing circuitry 215 according to well-known principles. The controller / processor 225 may also support additional functions, such as more advanced wireless communication capabilities. For example, the controller / processor 225 may support beamforming or directional routing operations in which signals from the multiple antennas 205a-205n are weighted differently to effectively steer them in a desired direction. Any of a variety of other functions may be supported in the gNB 102 by the controller / processor 225.

[0098] The controller / processor 225 may also execute programs and other processes residing in the memory 230, such as an operating system (OS). The controller / processor 225 may move data into and out of the memory 230 as required by the executing processes.

[0099] Additionally, the controller / processor 225 may be connected to a backhaul or network interface 235. The backhaul or network interface 235 allows the gNB 102 to communicate with other devices or systems via the backhaul connection or network. The interface 235 may support communication via any suitable wired or wireless connection(s). For example, when the gNB 102 is implemented as part of a cellular communication system (e.g., supporting 5G, LTE, or LTE-A), the interface 235 may allow the gNB 102 to communicate with other gNBs via a wired or wireless backhaul connection. When the gNB 102 is implemented as an access point, the interface 235 may allow the gNB 102 to communicate with a wired or wireless local area network, or a larger network (e.g., the Internet) via a wired or wireless connection. Interface 235 may include any suitable structure that supports communication via wired or wireless connections, such as Ethernet or RF transceivers.

[0100] Memory 230 may be connected to controller / processor 225. Part of memory 230 may include RAM, and another part of memory 230 may include flash memory or other ROM.

[0101] While FIG. 2 illustrates an example of a gNB 102, various modifications may be made to FIG. 2 . For example, the gNB 102 may include any number of each component illustrated in FIG. 2 . As a specific example, the access point may include multiple interfaces 235, and the controller / processor 225 may support routing functions for routing data between different network addresses. As another specific example, while illustrated as including a single instance of TX processing circuitry (215) and a single instance of RX processing circuitry (220), the gNB (102) may include multiple instances of each (e.g., one per RF transceiver).

[0102] Additionally, the various components of FIG. 2 may be combined, further subdivided, or omitted, and additional components may be added according to specific needs.

[0103] FIG. 3 illustrates an exemplary UE 116 according to embodiments of the present disclosure. The embodiment of UE 116 illustrated in FIG. 3 is for illustrative purposes only and may have the same or similar configuration as UEs 111-115 of FIG. 1 . However, UEs are provided in various configurations, and FIG. 3 does not limit the scope of the present disclosure to any particular implementation of a UE.

[0104] As illustrated in FIG. 3, the UE 116 may include an antenna 305, a radio frequency (RF) transceiver 310, transmit (TX) processing circuitry 315, a microphone 320, and receive (RX) processing circuitry 325. Additionally, the UE 116 may include a speaker 330, a processor 340, an input / output (I / O) interface (IF) 345, a touch screen 350, a display 355, and memory 360. The memory 360 may include an operating system (OS) 361 and one or more applications 362.

[0105] The RF transceiver 310 can receive an incoming RF signal transmitted by a gNB of the network 100 from an antenna 305. The RF transceiver 310 can downconvert the incoming RF signal to generate an intermediate frequency (IF) or baseband signal. The IF or baseband signals are transmitted to the RX processing circuitry 325, which can generate a processed baseband signal by filtering, decoding, and / or digitizing. The RX processing circuitry 325 can transmit the processed baseband signal to a speaker 330 (e.g., voice data) or a processor 340 for further processing (e.g., web browsing data).

[0106] The TX processing circuitry 315 may receive analog or digital voice data from the microphone 320 or other outgoing baseband data (such as web data, email, or interactive video game data) from the processor 340. The TX processing circuitry 315 may encode, multiplex, and / or digitize the transmit baseband data to generate a processed baseband or IF signal.

[0107] The RF transceiver 310 can receive a baseband or IF signal from the TX processing circuit 315 and up-convert the baseband or IF signal to an RF signal transmitted through the antenna 305.

[0108] The processor 340 may include one or more processors or other processing devices and may execute an OS 361 stored in the memory 360 to control the overall operation of the UE 116. For example, the controller / processor 225 may control the reception of forward channel signals and transmission of reverse channel signals by the RF transceivers 210a-210n, the RX processing circuitry 220, and the TX processing circuitry 215 according to well-known principles. In some embodiments, the processor 340 may include one or more microprocessors or microcontrollers.

[0109] Additionally, the processor 340 may execute other processes and programs residing in the memory 360, such as processes for beam management. The processor 340 may move data into and out of the memory 360 as required by the executing process. In one embodiment, the processor 340 may be configured to execute an application 362 based on the OS 361 or in response to signals received from the gNB or operator.

[0110] Additionally, the processor 340 is connected to an I / O interface 345, which may provide the UE 116 with the ability to connect to other devices, such as laptop computers and handheld computers.

[0111] Additionally, the processor 340 may be coupled to a touch screen 350 and a display 355. An operator of the UE 116 may use the touch screen 350 to enter data into the UE 116. The display 355 may be a liquid crystal display, a light emitting diode display, or other display capable of rendering text and / or at least limited graphics, such as a website.

[0112] Memory 360 may be coupled to processor 340. Part of memory 360 may include random access memory (RAM), and another part of memory 360 may include flash memory or other read-only memory (ROM).

[0113] FIG. 3 illustrates an example of UE 116, which may be modified in various ways. For example, various components of FIG. 3 may be combined, further subdivided, or omitted, and additional components may be added according to specific needs. As a specific example, processor 340 may be divided into multiple processors, such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs). FIG. 3 also illustrates UE 116 configured as a mobile phone or smart phone, although the UE may be configured to operate as other types of mobile or stationary devices.

[0114] The present disclosure relates generally to wireless communication systems, and more particularly to a vehicular communication network protocol including vehicle-to-device, vehicle-to-vehicle, and vehicle-to-network communication resource allocation and synchronization schemes.

[0115] A communication system may include a downlink (DL) that transmits signals from a transmission point such as a base station (BS) or NodeB to user equipment (UE), and an uplink (UL) that transmits signals from the UE to a receiving point such as a NodeB.

[0116] Additionally, sidelink (SL) can carry signals from UEs to other UEs or other non-infrastructure-based nodes. A UE, also commonly referred to as a terminal or mobile station, can be fixed or mobile and can be a mobile phone, personal computer, or other device. A NodeB, typically a fixed station, may also be referred to by other equivalent terms, such as an access point or eNodeB. The access network that includes NodeBs associated with 3GPP LTE is called the Evolved Universal Terrestrial Access Network (E-UTRAN).

[0117] NR system related

[0118] FIG. 4 is a diagram showing the basic structure of a time-frequency domain, which is a radio resource domain in which data or control channels are transmitted, in an NR system according to one embodiment of the present disclosure.

[0119] Specifically, FIG. 4 shows the basic structure of the time-frequency domain, which is a radio resource domain in which data or control channels are transmitted in the downlink or uplink in an NR system.

[0120] Referring to Fig. 4, the horizontal axis represents the time domain, and the vertical axis represents the frequency domain. The minimum transmission unit in the time domain is an OFDM symbol, and Nsymb OFDM symbols (1-02) can be combined to form one slot (1-06). The length of a subframe is defined as 1.0 ms, and a radio frame (1-14) is defined as 10 ms. The minimum transmission unit in the frequency domain is a subcarrier, and the bandwidth of the entire system transmission bandwidth can be composed of a total of NBW subcarriers (1-04).

[0121] In the time-frequency domain, the basic unit of resources is a resource element (RE) (1-12), which can be represented by an OFDM symbol index and a subcarrier index. A resource block (RB) (1-08, or physical resource block; PRB) can be defined as Nsymb consecutive OFDM symbols (1-02) in the time domain and NRB consecutive subcarriers (1-10) in the frequency domain. Therefore, one RB (1-08) can be composed of Nsymb x NRB REs (1-12). In general, the minimum transmission unit of data is an RB unit. In an NR system, Nsymb = 14, NRB = 12, and NBW and NRB can be proportional to the bandwidth of the system transmission band. In addition, the data rate can increase in proportion to the number of RBs scheduled to the terminal.

[0122] In the NR system, in the case of an FDD system that operates the downlink and uplink by frequency division, the downlink transmission bandwidth and the uplink transmission bandwidth may be different. The channel bandwidth may represent the RF bandwidth corresponding to the system transmission bandwidth. [Table 1] and [Table 2] show part of the correspondence between the system transmission bandwidth, subcarrier spacing, and channel bandwidth defined in the NR system in the frequency band lower than 6 GHz and the frequency band higher than 6 GHz, respectively. For example, an NR system with a 100 MHz channel bandwidth with a 30 kHz subcarrier width has a transmission bandwidth composed of 273 RBs. In the following, N / A may be a bandwidth-subcarrier combination that is not supported by the NR system.

[0123]

[0124]

[0125] In the NR system, the frequency range can be divided into FR1 and FR2 and defined as shown in Table 3 below.

[0126]

[0127] The ranges of FR1 and FR2 can be varied and applied differently. For example, the frequency range of FR1 can be varied and applied from 450 MHz to 6000 MHz.

[0128] In the NR system, scheduling information for downlink data or uplink data is transmitted from the base station to the terminal through downlink control information (DCI). DCI can be defined according to various formats, and each DCI can indicate whether it is scheduling information for uplink data (UL grant) or downlink data (DL grant), whether it is compact DCI with a control information size smaller than a predetermined size, whether it applies spatial multiplexing using multiple antennas, and whether it is DCI for power control. For example, DCI format 1-1, which is scheduling control information (DL grant) for downlink data, can include at least one of the following control information.

[0129] - Carrier indicator: Indicates on which frequency carrier the signal is transmitted.

[0130] - DCI format indicator: This is an indicator that distinguishes whether the DCI is for downlink or uplink.

[0131] - Bandwidth part (BWP) indicator: Indicates which BWP is being transmitted.

[0132] - Frequency domain resource allocation: Indicates the RBs in the frequency domain allocated for data transmission. The resources expressed are determined based on the system bandwidth and resource allocation method.

[0133] - Time domain resource allocation: Indicates in which OFDM symbol of which slot the data-related channel will be transmitted.

[0134] - VRB-to-PRB mapping: Indicates how to map the virtual RB (VRB) index and the physical RB (PRB) index.

[0135] - Modulation and coding scheme (MCS): Indicates the modulation method used for data transmission and the size of the transport block, which is the data to be transmitted.

[0136] - HARQ process number: Indicates the HARQ process number.

[0137] - New data indicator: Indicates whether this is a HARQ initial transmission or a retransmission.

[0138] - Redundancy version: Indicates the redundancy version of HARQ.

[0139] - Transmit power control (TPC) command for PUCCH (physical uplink control channel): Indicates a transmit power control command for PUCCH, which is an uplink control channel.

[0140] For data transmission via PDSCH or PUSCH, time domain resource assignment can be determined by information about the slot in which the PDSCH / PUSCH is transmitted, the starting symbol position S in the slot, and the number of symbols L to which the PDSCH / PUSCH is mapped. S can be a relative position from the start of the slot, L can be a number of consecutive symbols, and S and L can be determined from a start and length indicator value (SLIV) defined as follows.

[0141]

[0142] In the NR system, a terminal can receive information about a SLIV value, a PDSCH / PUSCH mapping type, and a slot in which PDSCH / PUSCH is transmitted through RRC configuration (for example, the information can be set in the form of a table). Afterwards, in time-domain resource allocation of DCI, the base station can transmit information about the SLIV value, the PDSCH / PUSCH mapping type, and the slot in which PDSCH / PUSCH is transmitted to the terminal by indicating an index value in the set table. In the NR system, the PDSCH mapping type can be defined as type A and type B. According to PDSCH mapping type A, the first symbol of the DMRS symbol can be located in the second or third OFDM symbol of a slot. According to PDSCH mapping type B, the first symbol of the DMRS symbol can be located in the first OFDM symbol in the time-domain resource allocated for PUSCH transmission.

[0143] DCI can be transmitted on the Physical Downlink Control Channel (PDCCH) after undergoing channel coding and modulation processes. In the present disclosure, when control information is transmitted via the PDCCH or PUCCH, it can be expressed as "PDCCH or PUCCH transmission." Similarly, in the present disclosure, when data is transmitted via the PUSCH or PDSCH, it can be expressed as "PUSCH or PDSCH transmission."

[0144] Typically, DCI is scrambled with a specific radio network temporary identifier (RNTI) (or terminal identifier) ​​for each terminal, a cyclic redundancy check (CRC) is added, channel-coded, and then transmitted as an independent PDCCH. PDCCHs can be mapped and transmitted from a control resource set (CORESET) configured for each terminal.

[0145] Downlink data can be transmitted on the physical downlink shared channel (PDSCH), a physical channel for downlink data transmission. The PDSCH can be transmitted after the control channel transmission period, and scheduling information, such as specific mapping locations and modulation methods in the frequency domain, can be determined based on the DCI transmitted via the PDCCH.

[0146] Among the control information constituting DCI, the base station can notify the terminal of the modulation method applied to the PDSCH to be transmitted and the size of the data to be transmitted (transport block size; TBS) through the MCS (Modulation Coding Scheme). According to an embodiment of the present disclosure, the MCS may be composed of 5 bits or more or fewer bits. The TBS (Transport Block Size) may correspond to the size of the data (transport block, TB) to be transmitted by the base station before channel coding for error correction is applied.

[0147] In the present disclosure, a transport block (TB) may include a MAC (medium access control) header, a MAC control element (CE), one or more MAC SDUs (service data units), and padding bits. Alternatively, a TB may represent a unit of data delivered from the MAC layer to the physical layer or a MAC PDU (protocol data unit).

[0148] The modulation methods supported in the NR system are QPSK (quadrature phase shift keying), 16QAM (quadrature amplitude modulation), 64QAM, and 256QAM, and the modulation orders (Qm) correspond to 2, 4, 6, and 8, respectively. That is, QPSK modulation can transmit 2 bits per symbol, 16QAM modulation can transmit 4 bits per symbol, 64QAM modulation can transmit 6 bits per symbol, and 256QAM modulation can transmit 8 bits per symbol.

[0149] LTE system related

[0150] Figures 5 and 6 schematically illustrate the structure of a wireless frame applied to the present disclosure.

[0151] Referring to FIGS. 5 and 6, one radio frame includes 10 subframes, and one subframe includes two consecutive slots. The basic time (length) unit for transmission control in a radio frame is called a Transmission Time Interval (TTI). A TTI can be 1 ms. The length of one subframe can be 1 ms, and the length of one slot can be 0.5 ms.

[0152] A slot may include multiple symbols in the time domain. For example, in the case of a wireless system using OFDMA (Orthogonal Frequency Division Multiple Access) in the downlink (DL), the symbol may be an OFDM (Orthogonal Frequency Division Multiplexing) symbol, and in the case of a wireless system using SC-FDMA (Single Carrier-Frequency Division Multiple Access) in the uplink (UL), the symbol may be an SC-FDMA (Single Carrier-Frequency Division Multiple Access) symbol. Meanwhile, the expression of a symbol period in the time domain is not limited by the multiple access method or name.

[0153] The number of symbols contained in a single slot may vary depending on the length of the CP (Cyclic Prefix). For example, in the case of a normal CP, one slot may contain seven symbols, and in the case of an extended CP, one slot may contain six symbols.

[0154] A resource element (RE) represents the smallest time-frequency unit to which modulation symbols of a data channel or modulation symbols of a control channel are mapped. A resource block (RB) is a resource allocation unit and includes time-frequency resources corresponding to 180 kHz in the frequency axis and 1 slot in the time axis. Meanwhile, a resource block pair (PBR) refers to a resource unit that includes two consecutive slots in the time axis.

[0155] In the physical layer, multiple physical channels can be used, and the physical channels can be mapped to the radio frame and transmitted. As a downlink physical channel, the Physical Downlink Control Channel (PDCCH) / Enhanced PDCCH (EPDCCH) informs the UE of resource allocation of the Paging Channel (PCH) and the Downlink Shared Channel (DL-SCH) and HARQ (Hybrid Automatic Repeat Request) information related to the DL-SCH. The PDCCH / EPDCCH can carry an uplink grant that informs the UE of resource allocation for uplink transmission. The PDCCH and EPDCCH differ in the resource area to which they are mapped. The DL-SCH is mapped to the Physical Downlink Shared Channel (PDSCH). The Physical Control Format Indicator Channel (PCFICH) informs the UE of the number of OFDM symbols used for the PDCCH, and is transmitted in every subframe. PHICH (Physical Hybrid ARQ Indicator Channel) is a downlink channel that carries HARQ (Hybrid Automatic Repeat reQuest) ACK (Acknowledgement) / NACK (Non-acknowledgement) signals, which are responses to uplink transmissions. The HARQ ACK / NACK signal can also be called a HARQ-ACK signal.

[0156] As an uplink physical channel, the Physical Random Access Channel (PRACH) carries a random access preamble. The Physical Uplink Control Channel (PUCCH) carries uplink control information such as HARQ-ACK, which is a response to downlink transmission, and channel status information (CSI) indicating the downlink channel status, such as the Channel Quality Indicator (CQI), precoding matrix index (PMI), precoding type indicator (PTI), and rank indicator (RI). The Physical Uplink Shared Channel (PUSCH) carries the Uplink Shared Channel (UL-SCH).

[0157] Uplink data may be transmitted on a PUSCH, and the uplink data may be a transport block (TB), which is a data block for an UL-SCH transmitted during a transmission time interval (TTI). The transport block may include user data. Alternatively, the uplink data may be multiplexed data. The multiplexed data may be a transport block for an UL-SCH and uplink control information multiplexed. That is, when there is user data to be transmitted on an uplink, the uplink control information may be multiplexed with the user data and transmitted through a PUSCH.

[0158] Sidelink (SL) General

[0159] Hereinafter, sidelink (SL) refers to a signal transmission and reception path between terminals, and it can be used interchangeably with the PC5 interface. Hereinafter, base station (BS) is the entity that performs resource allocation of terminals, and can be a BS that supports both V2X communication and general cellular communication, or a BS that supports only V2X communication. In other words, the BS can mean an NR BS (gNB), an LTE BS (eNB), or an RSU (road site unit) (or fixed station). A terminal may include not only a general user equipment, a mobile station, but also a vehicle supporting vehicular-to-vehicular (V2V) communication, a vehicle or pedestrian's handset (e.g., a smartphone) supporting vehicular-to-pedestrian (V2P) communication, a vehicle supporting vehicular-to-network (V2N) communication, or a vehicle supporting vehicular-to-infrastructure (V2I) communication, and an RSU equipped with a terminal function, an RSU equipped with a base station function, or an RSU equipped with a part of a base station function and a part of a terminal function. In the present disclosure, a downlink (DL) refers to a wireless transmission path of a signal transmitted from a base station to a terminal, and an uplink (UL) refers to a wireless transmission path of a signal transmitted from a terminal to a base station. Furthermore, while one embodiment of the present disclosure is described below based on an NR system, one embodiment of the present disclosure can also be applied to wireless communication systems with similar technical backgrounds or channel types. Furthermore, the embodiments of the present disclosure can be applied to other communication systems with some modifications, as determined by a person skilled in the art, without significantly departing from the scope of the present disclosure.

[0160] In this disclosure, the terms "physical channel" and "signal" may be used interchangeably with data or control signals. For example, while PDSCH is a physical channel through which data is transmitted, PDSCH may also refer to the data being transmitted.

[0161] Hereinafter, in the present disclosure, upper signaling means a signal transmission method in which a base station transmits a signal to a terminal using a downlink data channel of a physical layer, or a terminal transmits a signal to a base station using an uplink data channel of a physical layer, and may also be referred to as RRC signaling or a MAC control element (CE).

[0162] Figure 7 is a diagram illustrating side link communication performance.

[0163] Referring to FIG. 7, in order to transmit a packet, a UE (10) on the transmitting side requires resources (e.g., time and frequency) for transmitting sidelink control data and sidelink data. To obtain these resources, a UE (10) interested in sidelink communication can transmit a sidelink UE information (SidelinkUEInformation) message including a destination info list (destinationInfoList), i.e., a destination list, to a base station, i.e., an eNB (20) (S305).

[0164] The eNB (20) can allocate a sidelink resource pool (SC Pool) and sidelink Radio Network Temporary Identities (SL-RNTI) for transmitting sidelink control data through a Radio Resource Control (RRC) connection reconfiguration message (S310). The sidelink resource pool represents time and frequency resources for which sidelink control (scheduling control) data can be transmitted, i.e., at least one subframe and PRBs (Physical Resource Blocks) of each subframe. The time and frequency can be periodically allocated by a sidelink control cycle.

[0165] Thereafter, the UE (10) can request dedicated resources for sidelink control data and sidelink data transmission by transmitting a sidelink buffer status report (BSR) (S315).

[0166] The eNB (20) can allocate dedicated resources and transmit a grant (201) for sidelink communication, i.e., information about the dedicated resources (S320). The received single grant (201) may be for the first available sidelink control period starting after a specific number of subframes from the subframe at the end of the grant allocation period N (220-N) in which the single grant (201) was received. The UE (10) can transmit in the first available sidelink control period (210) using only one single grant (201) (S325).

[0167] FIG. 8 is a diagram for explaining the concept of cellular network-based D2D communication applied to the present disclosure.

[0168] Referring to FIG. 8, a cellular communication network is configured including a first base station (410), a second base station (420), and a first cluster (430). A first terminal (411) and a second terminal (412) belonging to a cell provided by the first base station (410) communicate through a normal access link (cellular link) via the first base station (410). This is an in-coverage-single-cell terminal-to-terminal communication scenario. Meanwhile, a first terminal (411) belonging to the first base station (410) can communicate with a fourth terminal (421) belonging to the second base station (420). This is an in-coverage-multi-cell terminal-to-terminal communication scenario. In addition, the fifth terminal (431) located outside the network coverage can create a cluster (430) with the sixth terminal (432) and the seventh terminal (433) and perform terminal-to-terminal communication with them. This is an out-of-coverage terminal-to-terminal communication scenario. In addition, the third terminal (413) can perform terminal-to-terminal communication with the sixth terminal (432), which is a partial-coverage terminal-to-terminal communication scenario. In this way, terminal-to-terminal communication links are possible between devices that have the same cell as their serving cell, between devices that have different cells as their serving cells, between devices connected to a serving cell and devices not connected to a serving cell, or between devices not connected to a serving cell. In particular, D2D communication may be required between devices located outside the network coverage for purposes such as public safety.

[0169] In order to transmit and receive D2D data via D2D communication, related control information must be transmitted and received between terminals. The related control information may be referred to as a Scheduling Assignment (SA). The Rx terminal may perform configuration for D2D data reception based on the SA. The SA may include, for example, at least one of a New Data Indicator (NDI), a Transmit UE Identification (Tx terminal ID), a Redundancy Version Indicator (RV indicator), a Modulation and Coding Scheme Indication (MCS indication), a Resource Allocation (RA) indication, and a power control indication.

[0170] Here, the NDI indicates whether the current transmission is a repetition of data, i.e., a retransmission, or a new transmission. The receiver can combine the same data based on the NDI. The Tx terminal ID indicates the ID of the transmitting terminal. The RV indicator indicates the redundancy version by specifying different starting points in the circular buffer for reading the encoded buffer. Based on the RV indicator, the transmitting terminal can choose from various redundancy versions for repetition of the same packet. The MCS indicator indicates the MCS level for D2D communication. The resource allocation indicator indicates to which time / frequency physical resources the corresponding D2D data is allocated and transmitted. The power control indicator will be a command for the terminal that received the information to control the appropriate power level for the corresponding D2D transmission.

[0171] For a terminal supporting D2D communication, the uplink channel of the (cellular) wireless communication system can be used as a radio resource for D2D communication. In this case, the SA and data for the D2D communication can be transmitted based on the structure of the PUSCH among the uplink physical channels of the wireless communication system. That is, the PUSCH structure can be reused for the physical channel for D2D communication. For example, the physical channel for D2D communication can have a 24-bit Cyclic Redundancy Check (CRC) inserted and turbo coding can be used. In addition, rate matching can be used for bit size matching and generating multiple transmissions. Scrambling can be used for interference randomization. A PUSCH DMRS (Demodulation Reference Signal) can be used. The DMRS is used for channel estimation for coherent demodulation of an uplink received signal.

[0172] FIG. 9 is a diagram illustrating a system according to one embodiment of the present disclosure.

[0173] Referring to (a) of FIG. 9, it shows a case where all V2X terminals (UE-1, UE-2) are located within the coverage of a base station (gNB / eNB / RSU) (in-coverage scenario). All V2X terminals (UE-1, UE-2) can receive data and control information from the base station (gNB / eNB / RSU) via downlink (DL) or transmit data and control information to the base station via uplink (UL). At this time, the data and control information may be data and control information for V2X communication or data and control information for general cellular communication, not V2X communication. In addition, in (a) of FIG. 9, V2X terminals (UE-1, UE-2) can transmit and receive data and control information for V2X communication via sidelink (Sidelink, SL).

[0174] Referring to (b) of FIG. 9, among V2X terminals, UE-1 is located within the coverage of the base station (gNB / eNB / RSU) and UE-2 is located outside the coverage of the base station (gNB / eNB / RSU) (partial coverage scenario). Referring to (b) of FIG. 9, the terminal (UE-1) located within the coverage of the base station can receive data and control information from the base station via downlink (DL) or transmit data and control information to the base station via uplink (UL). Referring to (b) of FIG. 9, the terminal (UE-2) located outside the coverage of the base station cannot receive data and control information from the base station via downlink and cannot transmit data and control information to the base station via uplink. The terminal (UE-2) can transmit and receive data and control information for V2X communication with the terminal (UE-1) via sidelink (SL).

[0175] Figure 9 (c) shows a case where all V2X terminals (UE-1, UE-2) are located outside the coverage of the base station (gNB / eNB / RSU). Referring to Figure 9 (c), the terminals (UE-1, UE-2) cannot receive data and control information from the base station via the downlink (DL), and cannot transmit data and control information to the base station via the uplink (UL). Meanwhile, the terminals (UE-1) and (UE-2) can transmit / receive data and control information for V2X communication via the sidelink (SL).

[0176] FIG. 9 (d) illustrates a case where a V2X transmitting terminal and a V2X receiving terminal are connected to different base stations (gNB / eNB / RSU) (RRC connected state) or are camping on them (RRC disconnected state, i.e., RRC idle state) (Inter-cell V2X communication). At this time, the terminal (UE-1) may be a V2X transmitting terminal and the terminal (UE-2) may be a V2X receiving terminal. Alternatively, the terminal (UE-1) may be a V2X receiving terminal and the terminal (UE-2) may be a V2X transmitting terminal. The terminal (UE-1) may receive a V2X-dedicated SIB (System Information Block) from a base station to which the terminal (UE-1) is connected (or on which it is camping), and the terminal (UE-2) may receive a V2X-dedicated SIB from another base station to which the terminal (UE-2) is connected (or on which it is camping). At this time, the information of the V2X-dedicated SIB received by the terminal (UE-1) and the information of the V2X-dedicated SIB received by the terminal (UE-2) may be different from each other. Therefore, in order to perform V2X communication between terminals located in different cells, it is necessary to unify the received SIB information.

[0177] In Fig. 9, a V2X system composed of two terminals (UE-1, UE-2) is described as an example for convenience of explanation, but the present invention is not limited thereto, and various numbers of terminals may participate in the V2X system. In addition, the uplink (UL) and downlink (DL) between the base station (eNB / gNB / RSU) and the V2X terminals (UE-1, UE-2) may be named as the Uu interface, and the sidelink (SL) between the V2X terminals (UE-1, UE-2) may be named as the PC5 interface. Therefore, in the present disclosure, these may be used interchangeably.

[0178] Meanwhile, in the present disclosure, a terminal may refer to a vehicle supporting vehicular-to-vehicular (V2V) communication, a vehicle supporting vehicular-to-pedestrian (V2P) communication, or a pedestrian's handset (e.g., a smartphone), a vehicle supporting vehicular-to-network (V2N) communication, or a vehicle supporting vehicular-to-infrastructure (V2I) communication. In addition, in the present disclosure, a terminal may refer to an RSU (Road Side Unit) equipped with a terminal function, an RSU equipped with a base station function, or an RSU equipped with a part of a base station function and a part of a terminal function.

[0179] In the present disclosure, a sidelink control channel may be referred to as a physical sidelink control channel (PSCCH), and a sidelink shared channel or data channel may be referred to as a physical sidelink shared channel (PSSCH). In addition, a broadcast channel broadcast with a synchronization signal may be referred to as a physical sidelink broadcast channel (PSBCH), and a channel for feedback transmission may be referred to as a physical sidelink feedback channel (PSFCH). However, either a PSCCH or a PSSCH may be used for feedback transmission. Depending on the communication system, it may be referred to as an LTE-PSCCH, an LTE-PSSCH, a NR-PSCCH, an NR-PSSCH, etc. In the present disclosure, a sidelink may refer to a link between terminals, and a Uu link may refer to a link between a base station and a terminal.

[0180] FIG. 10 is a diagram for explaining a resource pool defined as a set of time and frequency resources used for transmission and reception of a side link according to one embodiment of the present disclosure.

[0181] Referring to 1110 of FIG. 10, a case is illustrated where resource pools are allocated non-contiguously in time and frequency. While the present disclosure focuses on the case where resource pools are allocated non-contiguously in frequency, it is of course possible for resource pools to be allocated continuously in frequency.

[0182] Referring to 1120 of FIG. 10, non-contiguous resource allocation can be performed on a frequency basis. The granularity of resource allocation on a frequency basis can be a PRB (Physical Resource Block).

[0183] Also, referring to 1121 of FIG. 10, resource allocation on a frequency basis may be performed based on subchannels. A subchannel may be defined as a resource allocation unit on a frequency composed of multiple RBs. Specifically, a subchannel may be defined as an integer multiple of an RB. Referring to 1121 of FIG. 10, a case in which a subchannel is composed of four consecutive PRBs is illustrated. The size of the subchannel may be set differently, and although one subchannel is typically composed of consecutive PRBs, it is not necessarily required to be composed of consecutive PRBs. A subchannel may be a basic unit of resource allocation for a PSSCH (Physical Sidelink Shared Channel) or a PSCCH (Physical Sidelink Control Channel), and the size of the subchannel may be set differently depending on whether the channel is a PSSCH or a PSCCH. It should also be noted that a subchannel may be referred to as an RBG (Resource Block Group). Below, methods for allocating non-contiguous resource pools on a frequency basis and dividing the allocated resource pools into multiple sub-channels are described.

[0184] Referring to 1122 of FIG. 10, startRBSubchanel can indicate the starting position of a subchannel on a frequency in a resource pool.

[0185] A resource block, which is a frequency resource belonging to a resource pool for PSSCH in an LTE V2X system, can be determined in the same manner as in Table 5 below.

[0186]

[0187] 1130 in Figure 10 illustrates a case where resource allocation is discontinuous over time. The granularity of resource allocation over time can be a slot. While this disclosure focuses on the case where resource pools are allocated discontinuously over time, it is also possible for resource pools to be allocated continuously over time.

[0188] Referring to 1131 of FIG. 10, startSlot can indicate the starting position of a slot in time in a resource pool.

[0189] A subframe, which is a time resource belonging to a resource pool for PSSCH in an LTE V2X system, can be determined in the same manner as in Table 6 below.

[0190]

[0191] FIG. 11 is a flowchart illustrating a scheduled resource allocation (mode 1) method in a sidelink according to one embodiment of the present disclosure. The scheduled resource allocation (mode 1) method is a method in which a base station allocates resources used for sidelink transmission to RRC-connected terminals using a dedicated scheduling method. The scheduled resource allocation (mode 1) method is effective for interference management and resource pool management because the base station can manage sidelink resources.

[0192] Referring to FIG. 11, a terminal (1201) that is camping on (1205) can receive (1210) an SL SIB (Sidelink System Information Bit) from a base station (1203). The system information may include resource pool information for transmission and reception, setting information for sensing operation, information for setting synchronization, information for inter-frequency transmission and reception, etc. When data traffic for V2X is generated in the terminal (1201), an RRC connection with the base station can be performed (1220). Here, the RRC connection between the terminal and the base station can be referred to as Uu-RRC (1220). The Uu-RRC connection can be performed before data traffic for V2X is generated. The terminal (1201) can request transmission resources for V2X communication with other terminals (1202) from the base station (1203) (1230). At this time, the terminal (1201) can request transmission resources for V2X communication from the base station (1203) using an RRC message or MAC CE (1230). Here, SidelinkUEInformation and UEAssistanceInformation messages can be used as the RRC message. Meanwhile, the MAC CE can be a buffer status report MAC CE of a new format (including at least an indicator indicating that it is a buffer status report for V2X communication and information on the size of data buffered for D2D communication). For detailed format and contents of the buffer status report used in 3GPP, refer to 3GPP standard TS36.321 E-UTRA MAC Protocol Specification. The base station (1203) can allocate V2X transmission resources to the terminal (1201) through a dedicated Uu-RRC message. The dedicated Uu-RRC message can be included in the RRCConnectionReconfiguration message.The allocated resources may be V2X resources via Uu or resources for PC5 depending on the type of traffic requested by the terminal (1201) or congestion of the corresponding link. To determine resource allocation, the terminal may send additional PPPP (ProSe Per Packet Priority) or LCID (Logical Channel ID) information of the V2X traffic via UEAssistanceInformation or MAC CE. Since the base station (1203) also knows information about resources used by other terminals (1202), it can allocate the remaining resource pool among the resources requested by the terminal (1201) (12-35). The base station (1203) may instruct the terminal (1201) to perform final scheduling by transmitting DCI via PDCCH (1240).

[0193] In the case of broadcast transmission, a terminal (1201) can broadcast SCI (Sidelink Control Information) to other terminals (1202) via PSCCH without additional sidelink RRC configuration (1270). In addition, data can be broadcast to other terminals (12-02) via PSSCH (1270).

[0194] In contrast, in the case of unicast and groupcast transmission, the terminal (1201) can perform an RRC connection one-to-one with other terminals (1202). Here, the RRC connection between terminals can be named PC5-RRC to distinguish it from Uu-RRC. Even in the case of groupcast, the PC5-RRC (1215) can be individually connected between terminals in the group. In Fig. 11, the connection of the PC5-RRC (1215) is illustrated as an operation after the transmission of the SL SIB (1210), but it can be performed at any time before the transmission of the SL SIB (1210) or before the transmission of the SCI (1260). If an RRC connection is required between terminals, the PC5-RRC (1215) connection of the sidelink can be performed and the SCI (Sidelink Control Information) can be transmitted to other terminals (1202) through the PSCCH as a unicast or groupcast (1260). At this time, groupcast transmission of SCI may be interpreted as group SCI. In addition, data may be transmitted to other terminals (1202) via unicast or groupcast (1270) via PSSCH.

[0195] FIG. 12 is a flowchart illustrating a UE autonomous resource allocation (mode 2) method in a sidelink according to one embodiment of the present disclosure.

[0196] In the UE autonomous resource allocation (mode 2) method, the base station (1303) provides a sidelink transmission / reception resource pool for V2X as system information, and the terminal (1301) can select a transmission resource according to a set rule. Resource selection methods may include zone mapping, sensing-based resource selection, and random selection. Unlike the scheduled resource allocation (mode 1) method in which the base station (1303) directly participates in resource allocation, FIG. 12 differs from the scheduled resource allocation (mode 1) method in that the terminal (1301) autonomously selects a resource and transmits data based on a resource pool received in advance through system information. In V2X communication, the base station (1303) can allocate various types of resource pools (V2V resource pool, V2P resource pool) for the terminal (1301). The allocatable resource pool may be composed of a resource pool from which a terminal can autonomously select an available resource pool after sensing resources used by other surrounding terminals (1302), and a resource pool from which a terminal randomly selects a resource from a preset resource pool.

[0197] A terminal (1301) that is camping on (1305) can receive (1310) an SL SIB (Sidelink System Information Bit) from a base station (1303). The system information may include resource pool information for transmission and reception, setting information for sensing operation, information for setting synchronization, information for inter-frequency transmission and reception, etc. The difference in operation between FIG. 11 and FIG. 12 is that in the case of FIG. 11, the base station (1203) and the terminal (1201) operate in an RRC-connected state, whereas in FIG. 12, they can also operate in an idle mode (1320) without RRC connection. In addition, in the idle mode (1320) without RRC connection, the base station (1303) does not directly participate in resource allocation, and the terminal (1301) can operate to autonomously select transmission resources. When data traffic for V2X is generated in the terminal (1301), the terminal (1301) can select (1330) a resource pool in the time / frequency domain according to a set transmission operation among the resource pools received through system information from the base station (1303).

[0198] Next, in the case of broadcast transmission, the terminal (1301) can broadcast SCI (Sidelink Control Information) to other terminals (1302) via PSCCH without additional sidelink RRC configuration (1350). In addition, the terminal (1301) can broadcast data to other terminals (1302) via PSSCH (1360).

[0199] In contrast, in the case of unicast and groupcast transmission, a terminal (1301) can perform one-to-one RRC connection with other terminals (1302). Here, the RRC connection between terminals can be referred to as PC5-RRC to distinguish it from Uu-RRC. Even in the case of groupcast, PC5-RRC can be individually connected between terminals in a group. This may be similar to the connection of the RRC layer in the connection between the base station and the terminal in NR uplink and downlink, and the connection at the RRC layer level in the sidelink can be referred to as PC5-RRC. Through the PC5-RRC connection, terminal-to-terminal capability information (UE capability) for sidelink can be exchanged, or configuration information required for signal transmission and reception can be exchanged. In FIG. 12, the connection of PC5-RRC (1315) is illustrated as an operation after SL SIB transmission (13-10), but it can be performed at any time before SL SIB transmission (13-10) or SCI transmission (13-50). If an RRC connection is required between terminals, a PC5-RRC connection of the sidelink is performed (1315), and SCI (Sidelink Control Information) can be transmitted to other terminals (1302) via unicast or groupcast via PSCCH (1350). In this case, groupcast transmission of SCI can be interpreted as group SCI. In addition, data can be transmitted to other terminals (1302) via unicast and groupcast via PSSCH (1360).

[0200] Hereinafter, in the present disclosure, a transmitting terminal (TX UE) may be a terminal that transmits data to a (target) receiving terminal (RX UE). For example, the TX UE may be a terminal that performs PSCCH and / or PSSCH transmission. And / or, the TX UE may be a terminal that transmits an SL CSI-RS and / or an SL CSI report request indicator to the (target) RX UE. And / or the TX UE may be a terminal that transmits a (control) channel (e.g., PSCCH, PSSCH, etc.) and / or a reference signal (e.g., DM-RS, CSI-RS, etc.) on the (control) channel to be used for SL RLM and / or SL RLF operation of the (target) RX UE.

[0201] Also, in the present disclosure, a receiving terminal (RX UE) may be a terminal that transmits SL HARQ feedback to a transmitting terminal (TX UE) based on (i) whether decoding of data received from a TX UE is successful and / or (ii) whether detection / decoding of a PSCCH (related to PSSCH scheduling) transmitted by the TX UE is successful. And / or, the RX UE may be a terminal that performs SL CSI transmission to the TX UE based on an SL CSI-RS and / or an SL CSI report request indicator received from the TX UE. And / or, the RX UE may be a terminal that transmits an SL (L1) RSRP measurement value measured based on a (predefined) reference signal and / or an SL (L1) RSRP report request indicator received from the TX UE to the TX UE. And / or, the RX UE may be a terminal that transmits its own data to the TX UE. And / or, the RX UE may be a terminal that performs SL RLM and / or SL RLF operation based on a (pre-configured) (control) channel received from a TX UE and / or a reference signal on the (control) channel.

[0202] Meanwhile, in the present disclosure, for example, when the RX UE transmits SL HARQ feedback information for the PSSCH and / or PSCCH received from the TX UE, the following scheme or some of the following schemes may be considered. Here, for example, the following scheme or some of the following schemes may be applied only in a limited manner when the RX UE successfully decodes / detects the PSCCH that schedules the PSSCH.

[0203] Method (Option) 1) NACK information can be transmitted to the TX UE only when the RX UE fails to decode / receive the PSSCH received from the TX UE.

[0204] Method (Option) 2) If the RX UE succeeds in decoding / receiving the PSSCH received from the TX UE, it can transmit ACK information to the TX UE, and if the PSSCH decoding / reception fails, it can transmit NACK information to the TX UE.

[0205] Meanwhile, in the present disclosure, for example, the TX UE may transmit the following information or some of the following information to the RX UE via SCI. Here, for example, the TX UE may transmit some or all of the following information to the RX UE via the first SCI (FIRST SCI) and / or the second SCI (SECOND SCI).

[0206] - PSSCH (and / or PSCCH) related resource allocation information (e.g., time / frequency resource location / number, resource reservation information (e.g., period))

[0207] - SL CSI Report Request Indicator or SL (L1) RSRP (and / or SL (L1) RSRQ and / or SL (L1) RSSI) Report Request Indicator

[0208] - SL CSI Transmission Indicator (or SL (L1) RSRP (and / or SL (L1) RSRQ and / or SL (L1) RSSI) Information Transmission Indicator) (on PSSCH)

[0209] - MCS information

[0210] - TX POWER information

[0211] - L1 DESTINATION ID information and / or L1 SOURCE ID information

[0212] - SL HARQ PROCESS ID information

[0213] - NDI information

[0214] - RV Information

[0215] - (Transmission TRAFFIC / PACKET related) QoS information (e.g. PRIORITY information)

[0216] - SL CSI-RS transmission indicator or information on the number of SL CSI-RS antenna ports (to be transmitted)

[0217] - TX UE location information or location (or range area) information of the target RX UE (for which SL HARQ feedback is requested).

[0218] - Reference signal (e.g., DM-RS, etc.) information related to decoding (and / or channel estimation) of data transmitted via PSSCH. For example, this may be information related to the pattern of (time-frequency) mapping resources of DM-RS, RANK information, antenna port index information, etc.

[0219] Meanwhile, in the present disclosure, since the TX UE can transmit SCI, first SCI (FIRST SCI) and / or second SCI (SECOND SCI) to the RX UE via the PSCCH, the PSCCH can be replaced / substituted with (i) SCI and / or (ii) FIRST SCI and / or (iii) SECOND SCI. And / or, the SCI can be replaced / substituted with the PSCCH and / or the FIRST SCI and / or the SECOND SCI. And / or, since the TX UE can transmit SECOND SCI to the RX UE via the PSSCH, the PSSCH can be replaced / substituted with the SECOND SCI.

[0220] Meanwhile, in the present disclosure, for example, when SCI configuration fields are divided into two groups in consideration of a (relatively) high SCI payload size, the first SCI including the first SCI configuration field group may be referred to as FIRST SCI, and the second SCI including the second SCI configuration field group may be referred to as SECOND SCI. In addition, for example, the FIRST SCI may be transmitted to the receiving terminal via the PSCCH. In addition, for example, the SECOND SCI may be transmitted to the receiving terminal via the (independent) PSCCH, or may be transmitted piggybacked with data via the PSSCH.

[0221] Meanwhile, in the present disclosure, for example, “configuration” or “definition” may mean (resource pool specific) (PRE)CONFIGURATION (via predefined signaling (e.g., SIB, MAC, RRC, etc.)) from a base station or network.

[0222] Meanwhile, in the present disclosure, for example, RLF can be determined based on an OUT-OF-SYNCH (OOS) indicator or an IN-SYNCH (IS) indicator, and thus can be replaced / substituted with OUT-OF-SYNCH (OOS) or IN-SYNCH (IS).

[0223] Meanwhile, in the present disclosure, for example, RB may be replaced / substituted with SUBCARRIER. Also, as an example, in the present disclosure, PACKET or TRAFFIC may be replaced / substituted with TB or MAC PDU depending on the layer being transmitted.

[0224] Meanwhile, in the present disclosure, CBG or CG may be replaced / substituted with TB.

[0225] Meanwhile, in the present disclosure, for example, the SOURCE ID may be replaced / substituted with the DESTINATION ID.

[0226] Meanwhile, in the present disclosure, for example, the L1 ID may be replaced / substituted with the L2 ID. For example, the L1 ID may be the L1 SOURCE ID or the L1 DESTINATION ID. For example, the L2 ID may be the L2 SOURCE ID or the L2 DESTINATION ID.

[0227] Research on Sidelink Relay for V2X communications aims to address challenges arising from vehicular networking environments and optimize vehicle-to-vehicle communications. Specifically, the introduction of Sidelink radio technology in 3GPP Rel-17 for 5G NR V2X introduces new possibilities for direct UE-to-UE connectivity, eliminating the need for base station intervention, reducing latency, and improving data efficiency (see Figure 13).

[0228] Figure 13 illustrates two modes for radio resource management. This technological innovation also introduces two flexible radio resource management modes to accommodate the diverse requirements of V2V direct communication under various coverage conditions. In Mode 1, control plane data is exchanged via the Uu interface, and radio resources are centrally allocated and reserved by the base station (BS). In Mode 2, the UE autonomously selects and manages radio resources without BS assistance. The presence of these two modes provides system flexibility in various scenarios. Mode 1, facilitated by centralized BS control, ensures efficient resource allocation. In contrast, Mode 2 allows vehicles to autonomously select and manage radio resources, enhancing system adaptability, especially in scenarios where BS coverage is insufficient or unavailable. In Sidelink Relay, coverage extension and power savings are key objectives. Relay operation is described below with reference to Figures 14 to 16.

[0229] Figure 14 is an example of a scenario related to UE to Network relay. Figure 15 is another example of a scenario related to UE to Network relay.

[0230] Figure 16 is an example of a scenario related to UE to UE relay. Figure 17 is another example of a scenario related to UE to UE relay.

[0231] When a remote UE is outside the service area, the relay acts as an intermediate node. As illustrated in Figures 14 and 16, the relay provides connectivity and ensures the integrity and timeliness of information transmission.

[0232] Conversely, when both the terminal and the remote UE are within the service coverage area, the role of the relay extends beyond improving connection quality. As illustrated in Figures 15 and 17, the relay can jointly reduce network resource consumption.

[0233] Research on relay selection algorithms is urgently needed. First, faced with the challenge of insufficient vehicle coverage, implementing an algorithm can intelligently select relay vehicles in blind spots or edge areas of vehicle communication, thereby maintaining communication stability and reliability. Second, optimizing relay selection can effectively optimize network resource utilization, reduce congestion, improve data transmission efficiency, and decrease communication delay. Furthermore, intelligent relay selection can reduce vehicle communication energy consumption, extend battery life, and enhance vehicle sustainability and durability.

[0234] The problems to be solved in this disclosure are as follows.

[0235] By designing a reasonable relay terminal selection algorithm, communication transmission distance can be optimized and signal quality improved. The communication range is determined by the relay terminal selection, allowing the terminal to communicate with other terminals and infrastructure. Furthermore, a better relay selection algorithm helps reduce energy consumption, allowing more terminals and devices to participate in the system without consuming excessive energy. Therefore, the relay selection algorithm must consider both transmission distance and energy consumption to achieve optimal system performance.

[0236] This disclosure proposes a relay selection method based on a Fuzzy Inference System (FIS). The proposed method can increase the information transmission range of a terminal and reduce its own energy consumption.

[0237] In the present disclosure, a terminal may include a terminal with mobility. For example, the terminal may be a vehicle. A relay terminal may be interpreted / replaced with a relay vehicle.

[0238] Hereinafter, a relay terminal selection method according to an embodiment of the present disclosure will be specifically described with reference to FIG. 18.

[0239] Fig. 18 illustrates a flowchart related to the selection of a relay terminal according to an embodiment of the present disclosure. In the following description, a vehicle, a relay vehicle, and a relay candidate vehicle may be interpreted / replaced with a terminal (UE), a relay terminal (relay UE), and a relay candidate terminal (relay candidate UE), respectively.

[0240] [Step 1- Parameter initialization]

[0241] At the start of the simulation, the configuration file (WiLabV2Xsim.cfg) is read, and the parameter values ​​contained in the file overwrite the default values. Based on the WiLabV2X simulator, the key parameters of the V2X communication model for high-speed scenarios, such as linear density, road length, road width, number of lanes per direction, and mean and variance of speeds, are first initialized.

[0242] [Step 2 - UE Position update]

[0243] In the first step, some parameters are initialized and the positions of each terminal (UE) / vehicle are randomly generated. The positions of terminals on the road must be continuously updated within a set number of cycles.

[0244] [Step 3 - Generate New Packet]

[0245] At this stage, the simulator generates new packets (communication information) for transmission and reception by the vehicle.

[0246] [Step 4- Direct Transmission]

[0247] This step is a process for direct transmission for V2X.

[0248] [Step 4.1- LTE Subframe start]

[0249] [Step 4.2- Get sensing information]

[0250] The relay process is performed using the sensing information obtained over 100ms.

[0251] [Step 4.3- Identify All Transmitting Tx]

[0252] Based on the above sensing information, it is determined how many vehicles are transmitting and which vehicle is transmitting Tx.

[0253] [Step 4.4- LTE Subframe end]

[0254] [Step 5- Relay Transmission]

[0255] In this step, relay selection based on fuzzy inference systems is performed for relay transmission.

[0256] [Step 5.1.1]

[0257] SINR threshold ( ) is calculated.

[0258] SINR (Signal to Interference plus Noise Ratio) is calculated as the ratio between i) the received power (assumed to be constant during the short period of packet transmission) and ii) the sum of the noise power and the average interference, which is the average of the instantaneous interference. That is, SINR can be expressed as S / N+Iav, where S is the received power, N is the noise power, and Iav is the average interference.

[0259] SINR threshold( ) is used to evaluate the accuracy of each transmission. For example, the SINR threshold( ) can be calculated based on the adopted MCS (Modulation and Coding Scheme) m and packet size B. For example, the SINR threshold ( ) can be defined / set in advance.

[0260] [Step 5.1.2]

[0261] SINR values ​​of all receiving vehicles (Rx) ( ) is calculated.

[0262] Specifically, if the calculation of SINR values ​​of all receiving vehicles (Rx) and the operations based on the calculation (Step 5.1.3 to Step 5.1.5) are completed, Step 5.1.6 is performed. Otherwise, Step 5.1.3 is performed.

[0263] [Step 5.1.3]

[0264] The SINR value of the current receiving vehicle ( )class Compare. If so, Step 5.1.4 is performed. Otherwise, Step 5.1.2 is returned. That is, the SINR value of the next receiving vehicle is calculated and actions based on this (Step 5.1.3 to Step 5.1.5) are performed.

[0265] [Step 5.1.4]

[0266] The current receiving vehicle is a relay candidate UE (relay candidate UE, ) is determined.

[0267] [Step 5.1.5]

[0268] Relay candidate vehicle ( ) within the transmission radius (the number of neighbor vehicles, ) is calculated.

[0269] [Step 5.1.6]

[0270] A set of candidates is stored. Specifically, information related to relay candidate vehicles ( ) is saved. is the SINR value of all relay candidate vehicles ( ) and the number of surrounding vehicles ( ) includes ( ).

[0271] [Step 5.2.1]

[0272] Information related to the above relay candidate vehicles ( )at and Each maximum and minimum value is selected. Specifically, The maximum value of ( ), The minimum value of ( ), The maximum value of ( ) and The minimum value of ( ) is selected. Based on this, each candidate vehicle ( ) for relay probability ( ) is decided.

[0273] [Step 5.2.2]

[0274] All candidate vehicles within ( ) for calculations (i.e., It is determined whether the calculation) has been performed. Specifically, All candidate vehicles within ( ) for relay probability( ) is determined / calculated, Step 5.2.7 is performed. Otherwise, Step 5.2.3 is performed.

[0275] [Step 5.2.3]

[0276] Candidate vehicle( ) for relay probability ( ) can be determined based on a fuzzy inference system (Fig. 20).

[0277] The input variables for the fuzzy inference system can be calculated as follows.

[0278] is the first fuzzy input variable and can be calculated as shown in the following mathematical expression 1.

[0279]

[0280] is the second fuzzy input variable and can be calculated as shown in the following mathematical expression 2.

[0281]

[0282] Each fuzzy input variable ( , ) are as follows: Four linguistic terms for:

[0283] i) Low (L),

[0284] ii) Average (A)

[0285] iii) Above Average (AA)

[0286] iv) High (H)

[0287] [Step 5.2.4]

[0288] Crisp input values ​​are converted into fuzzy values ​​using information in the knowledge base.

[0289] [Step 5.2.5]

[0290] Information in the above knowledge base may be information about rules related to a fuzzy inference system. Fig. 19 illustrates a rule base of a fuzzy inference system related to relay terminal selection according to an embodiment of the present disclosure. Referring to Fig. 19, a vehicle relay probability, which is a fuzzy output variable, ) can be set up as shown in Fig. 19. The five linguistic terms for output are as follows.

[0291] i) Low (L),

[0292] ii) Below Average (BL)

[0293] iii) Average (A)

[0294] iv) Above Average (AA)

[0295] v) High (H)

[0296] Figures 20 to 23 illustrate the structure, first / second input variables, and output of the above-described fuzzy inference system.

[0297] Figure 20 illustrates the structure of a fuzzy inference system according to an embodiment of the present disclosure.

[0298] Fig. 21 illustrates a membership function for a first input of a fuzzy inference system according to an embodiment of the present disclosure. Fig. 22 illustrates a membership function for a second input of a fuzzy inference system according to an embodiment of the present disclosure.

[0299] FIG. 23 illustrates a membership function for the output of a fuzzy inference system according to an embodiment of the present disclosure.

[0300] [Step 5.2.6]

[0301] Candidate vehicle( ) for relay probability ( ) is stored. For example, relay probability information ( ) may include a relay probability for each candidate vehicle ( ).

[0302] [Step 5.2.7]

[0303] All relay probabilities ( ) The relay vehicle is determined based on the comparison of values. Specifically, the highest Candidate vehicles with values ​​( ) is selected as the above relay vehicle.

[0304] [Step 5.3]

[0305] Relay vehicle ( ) starts the LTE subframe.

[0306] [Step 5.4]

[0307] The LTE subframe ends.

[0308] [Step 6 -Storage performance results]

[0309] When a relay transmission is completed, all results associated with each information transmission are saved.

[0310] [Step 7 - Next Event]

[0311] It checks whether the next event has ended.

[0312] [Step 8 -Output All performance results]

[0313] Figure 24 illustrates the selection of a relay terminal and relay transmission according to an embodiment of the present disclosure. Referring to Figure 24, a relay terminal (i.e., a relay vehicle) may be selected using the fuzzy inference system described above. The selected vehicle may be the candidate vehicle with the highest relay probability among the candidate vehicles.

[0314] The theoretical model related to the scenario according to Fig. 24 is as follows.

[0315] # Poisson distribution (random on parallel lines), modeling a highway.

[0316] # Key parameters: linear density, road length, road width, number of lanes per direction.

[0317] Table 7 below illustrates parameters related to the simulation of a highway scenario.

[0318]

[0319] Hereinafter, with reference to FIGS. 25 to 28, the performance (i.e., packet reception ratio, PRR) of direct transmission and relay-based transmission according to an embodiment of the present disclosure is compared.

[0320] FIG. 25 is a graph showing packet reception rates of relay-based transmission and direct transmission according to an embodiment of the present disclosure under certain transmission power conditions.

[0321] In Figure 25, the transmission power (Ptx) is fixed at 23 (dBm), and the PRR according to the density (rho) of different vehicles is shown. Relay transmission based on the embodiment of the present disclosure shows a higher PRR than direct transmission. As rho increases, resource collisions between vehicles lead to reception failures. That is, for both direct transmission and relay transmission, the higher rho, the lower the PRR.

[0322] Figures 26 to 28 are graphs showing packet reception rates of relay transmission and direct transmission according to embodiments of the present disclosure at different densities.

[0323] Specifically, in FIGS. 26 to 28, the densities (rho) are 100, 200, and 300, respectively. When the transmission power (Ptx) is 11 dbm, the performance of relay-based transmission is higher than that of direct transmission within a certain range (<100 m). Therefore, energy consumption can be reduced by reducing the transmission power of the transmission vehicle within the above-mentioned certain range.

[0324] The various embodiments of the present disclosure may be combined with each other.

[0325] In terms of implementation, the operations of the terminal according to the embodiments described above (e.g., operations related to relay selection) can be processed by the devices of FIGS. 1 to 3 (e.g., the processor (225) of FIG. 2, the processor (340) of FIG. 3).

[0326] In addition, the operations of the terminal according to the above-described embodiment (e.g., operations related to relay selection) may be stored in a memory (e.g., 230 of FIG. 2, 360 of FIG. 3) in the form of instructions / programs (e.g., instructions, executable codes) for driving at least one processor (e.g., processor (225) of FIG. 2 / processor (340) of FIG. 3).

[0327] The embodiments described below are specifically described with reference to FIG. 29 in terms of terminal operation. The methods described below are distinguished for convenience of explanation, and it is understood that some components of one method may be substituted for or combined with some components of another method.

[0328] FIG. 29 is a flowchart illustrating a method performed by a terminal according to one embodiment of the present disclosure.

[0329] Referring to FIG. 29, a method performed by a terminal according to one embodiment of the present disclosure includes a step of determining candidate terminals related to a sidelink relay (S2910) and a step of determining a relay terminal among the candidate terminals (S2920).

[0330] In step S2910, the terminal determines candidate terminals associated with the sidelink relay. The candidate terminals may be determined based on at least one of Steps 5.1.1 to 5.1.6 described above. For example, the signal-to-interference plus noise ratio (SINR) of each candidate terminal may be greater than an SINR threshold. For example, the terminal may determine, among receiving terminals within the transmission range of the terminal, a terminal with an SINR greater than the SINR threshold as a candidate terminal.

[0331] In S2920, the terminal determines a relay UE among the candidate terminals.

[0332] In one embodiment, the relay UE may be a candidate terminal with the highest probability determined based on fuzzy inference among the candidate terminals. The probability is determined based on each of the candidate vehicles described above. ) for relay probability ( ) can be based on.

[0333] The above probability can be determined based on i) first input variables and second input variables associated with each candidate terminal and ii) rules associated with the fuzzy inference.

[0334] For example, the first input variable may be related to the signal-to-interference plus noise ratio (SINR) of each candidate terminal. The second input variable may be related to the number of surrounding terminals within the transmission radius of each candidate terminal.

[0335] Specifically, the first input variable may be determined based on i) the SINR, ii) an SINR threshold, iii) a largest SINR among the SINRs associated with the candidate terminals, and iv) a smallest SINR among the SINRs. The first input variable may be determined based on the following mathematical equation.

[0336] [Mathematical formula]

[0337]

[0338] is the first input variable, is the above SINR, is the SINR threshold, is the largest SINR above, is the smallest SINR above.

[0339] The second input variable may be determined based on i) the number of peripheral terminals, ii) the largest value among the numbers of peripheral terminals related to the candidate terminals, and iii) the smallest value among the numbers of peripheral terminals.

[0340] The above second input variable can be determined based on the following mathematical formula.

[0341] [Mathematical formula]

[0342]

[0343] is the second input variable, is the number of peripheral terminals, is the largest value among the numbers of the above peripheral terminals, is the smallest value among the numbers of the above peripheral terminals.

[0344] For example, one of the first linguistic terms may be determined based on the first input variable. The first linguistic terms may include i) low (L), ii) average (A), iii) above average (AA), and iv) high (H).

[0345] For example, one of the second linguistic terms may be determined based on the second input variable. The second linguistic terms may include i) low (L), ii) average (A), iii) above average (AA), and iv) high (H).

[0346] For example, third language terms based on the first language terms and the second language terms may be defined by the above rules. As a specific example, the third language terms may include i) low (L), ii) below average (BL), iii) average (A), iv) above average (AA), and v) high (H). The probability may be based on one of the third language terms.

[0347] The operations based on S2910 to S2930 described above can be implemented by the device of FIG. 3. For example, one or more processors (340) can control one or more transceivers (310) and / or one or more memories (360) to perform the operations based on S2910 to S2930.

[0348] Although not limited thereto, the various descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed in this document may be applied to various fields requiring wireless communication / connectivity (e.g., 5G) between devices.

[0349] The operations described above can be realized by providing a memory device storing the corresponding program code in any component within the UE or eNB. That is, the control unit of the UE or eNB can execute the operations described above by reading and executing the program code stored in the memory device using a processor or CPU (Central Processing Unit).

[0350] The various components and modules of the UE or eNB described in the present disclosure may be operated using hardware circuits, such as logic circuits based on complementary metal oxide semiconductors, firmware, software, and / or hardware and firmware and / or software embedded in a machine-readable medium. For example, various electrical structures and methods may be implemented using electrical circuits such as transistors, logic gates, and application-specific semiconductors.

[0351] While the detailed description of this disclosure has described specific embodiments, it should be understood that various modifications are possible without departing from the scope of this disclosure. Therefore, the scope of this disclosure should not be limited to the described embodiments, but should be defined not only by the scope of the claims described below, but also by equivalents thereof.

Claims

1. In a method performed by a terminal, A step of determining candidate terminals related to sidelink relay; and A step of determining a relay UE among the above candidate terminals; including, The relay UE is a candidate terminal with the highest probability determined based on fuzzy inference among the candidate terminals. The above probability is determined based on i) the first input variable and the second input variable associated with each candidate terminal and ii) the rule associated with the fuzzy inference, A method characterized in that the first input variable is related to the signal to interference plus noise ratio (SINR) of each candidate terminal, and the second input variable is related to the number of surrounding terminals within the transmission radius of each candidate terminal.

2. In paragraph 1, A method characterized in that the first input variable is determined based on i) the SINR, ii) an SINR threshold, iii) a largest SINR among the SINRs associated with the candidate terminals, and iv) a smallest SINR among the SINRs.

3. In paragraph 2, The above first input variable is determined based on the following mathematical formula: [Mathematical formula] is the first input variable, is the above SINR, is the SINR threshold, is the largest SINR above, A method characterized in that the smallest SINR is as above.

4. In paragraph 1, A method characterized in that the second input variable is determined based on i) the number of the peripheral terminals, ii) the largest value among the numbers of the peripheral terminals related to the candidate terminals, and iii) the smallest value among the numbers of the peripheral terminals.

5. In paragraph 4, The above second input variable can be determined based on the following mathematical formula. [Mathematical formula] is the second input variable, is the number of peripheral terminals, is the largest value among the numbers of the above peripheral terminals, A method characterized in that the number of peripheral terminals is the smallest value among the numbers of peripheral terminals.

6. In paragraph 1, Based on the first input variable, one of the first linguistic terms is determined, A method characterized in that one of the second linguistic terms is determined based on the second input variable.

7. In paragraph 6, Third language terms based on the first language terms and the second language terms are defined by the above rules, A method characterized in that the above probability is based on one of the third language terms.

8. In paragraph 1, A method characterized in that the above SINR is greater than a SINR threshold.

9. In the terminal, One or more transmitters and receivers; one or more processors; and storing instructions for operations to be executed by said one or more processors, and including one or more memories connected to said one or more processors, The above actions are, A step of determining candidate terminals related to sidelink relay; and A step of determining a relay UE among the above candidate terminals; including, The relay UE is a candidate terminal with the highest probability determined based on fuzzy inference among the candidate terminals. The above probability is determined based on i) the first input variable and the second input variable associated with each candidate terminal and ii) the rule associated with the fuzzy inference, A terminal characterized in that the first input variable is related to the signal to interference plus noise ratio (SINR) of each candidate terminal, and the second input variable is related to the number of surrounding terminals within the transmission radius of each candidate terminal.

10. In a device including one or more memories and one or more processors connected to the one or more memories, The one or more memories store instructions that cause the one or more processors to perform operations based on what is executed by the one or more processors, The above actions are, A step of determining candidate terminals related to sidelink relay; and A step of determining a relay UE among the above candidate terminals; including, The relay UE is a candidate terminal with the highest probability determined based on fuzzy inference among the candidate terminals. The above probability is determined based on i) the first input variable and the second input variable associated with each candidate terminal and ii) the rule associated with the fuzzy inference, A device characterized in that the first input variable is related to the signal to interference plus noise ratio (SINR) of each candidate terminal, and the second input variable is related to the number of surrounding terminals within the transmission radius of each candidate terminal.

11. In one or more non-transitory computer-readable media storing instructions, The instructions executable by one or more processors cause the one or more processors to perform operations, The above actions are, A step of determining candidate terminals related to sidelink relay; and A step of determining a relay UE among the above candidate terminals; including, The relay UE is a candidate terminal with the highest probability determined based on fuzzy inference among the candidate terminals. The above probability is determined based on i) the first input variable and the second input variable associated with each candidate terminal and ii) the rule associated with the fuzzy inference, One or more non-transitory computer-readable media characterized in that the first input variable is related to a signal to interference plus noise ratio (SINR) of each candidate terminal, and the second input variable is related to the number of surrounding terminals within a transmission radius of each candidate terminal.

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