Method and apparatus for performing relay communication in a wireless communication system

Abstract

A method and apparatus for performing communication in a wireless communication system according to various embodiments are disclosed. The apparatus can transmit a first discovery message based on a hop count related to a multi-hop UE-to-Network (U2N) relay not being designated, receive a second discovery message, and determine a first hop count related to a first relay UE based on the second discovery message including information about the first relay UE.

Description

Technical Field

[0001] This disclosure relates to a method and apparatus for performing multi-hop-based relay communication in a wireless communication system. Background Technology

[0002] Wireless communication systems have been widely deployed to provide various types of communication services, such as voice or data. Typically, a wireless communication system is a multiple access system that supports communication for multiple users by sharing available system resources (bandwidth, transmission power, etc.). Examples of multiple access systems include Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single-Carrier Frequency Division Multiple Access (SC-FDMA), and Multi-Carrier Frequency Division Multiple Access (MC-FDMA).

[0003] Sidelink (SL) is a communication method in which a direct link is established between user equipment (UEs), and voice or data is exchanged directly between terminals without passing through a base station (BS). SL is considered a way to address the burden on base stations caused by the rapid increase in data traffic.

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

[0005] As more and more communication devices require greater communication capacity when sending and receiving signals, there is a need for mobile broadband communications that improve upon traditional radio access technologies. Therefore, communication systems considering services / UEs that are sensitive to reliability and latency are being discussed. Next-generation radio access technologies that consider enhanced mobile broadband communications, massive machine-type communications (MTC), and ultra-reliable low-latency communications (URLLC) can be referred to as new radio access technologies (RAT) or new radio (NR). Even within NR, vehicle-to-everything (V2X) communications can be supported.

[0006] Figure 1 This is a diagram used to compare RAT-based V2X communication before NR with NR-based V2X communication.

[0007] Regarding V2X communication, the RAT prior to NR primarily discussed schemes for providing security services based on V2X messages, such as Basic Security Messages (BSM), Collaboration-Aware Messages (CAM), and Distributed Environment Notification Messages (DENM). V2X messages can include location information, dynamic information, and attribute information. For example, a UE can send periodic message type CAM and / or event-triggered message type DENM to another UE.

[0008] For example, a CAM can include dynamic state information such as the vehicle's direction and speed, static vehicle data such as dimensions, and basic vehicle information such as external lighting conditions and route details. For example, a UE can broadcast a CAM, and the CAM latency can be less than 100ms. For example, in the event of an unexpected situation such as a vehicle malfunction or accident, a UE can generate a DENM and send it to another UE. For example, all vehicles within the UE's transmission coverage area can receive the CAM and / or DENM. In this case, the DENM can have a higher priority than the CAM.

[0009] Regarding V2X communication, various V2X scenarios were subsequently introduced in NR. For example, various V2X scenarios can include vehicle queuing, advanced driving, extended sensors, and remote driving.

[0010] For example, based on vehicle queuing, vehicles can dynamically form groups and move together. For example, to perform queuing operations based on vehicle queuing, vehicles belonging to the group can receive periodic data from the lead vehicle. For example, vehicles belonging to the group can decrease or increase the distance between vehicles based on periodic data.

[0011] For example, based on advanced driving, vehicles can be semi-autonomous or fully autonomous. For instance, each vehicle can adjust its trajectory or operation based on data acquired from local sensors of nearby vehicles and / or nearby logical entities. Furthermore, for example, each vehicle can share driving intentions with nearby vehicles.

[0012] For example, based on extended sensors, raw or processed data acquired through local sensors, or real-time video data, can be exchanged between the vehicle, logical entity, UE (User Equipment) of pedestrians, and / or V2X application servers. Thus, for example, a vehicle can identify an improved environment compared to the environment it could detect using its own sensors.

[0013] For example, for remote vehicles operated by unlicensed individuals or in hazardous environments, remote drivers or V2X applications can operate or control remote vehicles based on remote driving. For instance, when routes are predictable, such as in public transportation situations, cloud-based driving can be used to operate or control remote vehicles. For example, for remote driving, access to a cloud-based backend service platform could be considered.

[0014] In the field of NR-based V2X communications, methods are being discussed for specifying service requirements for various V2X scenarios such as vehicle platooning, advanced driving, extended sensors, and remote driving. Summary of the Invention

[0015] Technical issues

[0016] The purpose of this disclosure is to provide a method for performing multi-hop-based U2N relay communication more accurately and efficiently.

[0017] Those skilled in the art will understand that the objectives achievable by the embodiments are not limited to those specifically described above, and that the above and other objectives will become clearer from the following detailed description.

[0018] Technical solution

[0019] According to one aspect, a method performed by a first relay user equipment (UE) may include: sending a first discovery message based on the fact that a hop count associated with a multi-hop UE-to-network (U2N) relay has not been specified; receiving a second discovery message; and determining a first hop count associated with the first relay UE based on the second discovery message including information about the first relay UE.

[0020] Alternatively, the transmission of the first discovery message can be triggered even if no discovery message is received from another relay UE, to specify the hop count associated with the multi-hop U2N relay.

[0021] Alternatively, the first discovery message may include user information of the first relay UE and a hop count set to indicate that the hop count has not been specified.

[0022] Alternatively, the first relay UE may be an intermediate relay UE whose signal strength to the base station (BS) is less than a preset threshold.

[0023] Alternatively, the first hop count can be determined as a value obtained by incrementing the hop count value included in the second discovery message by 1.

[0024] Alternatively, the first discovery message may also include indication information indicating that U2N relay operations are based on multi-hops.

[0025] Alternatively, the method may further include triggering the transmission of a third discovery message based on the reception of the second discovery message, and the third discovery message may include the first hop count and the user information identifier of the second relay UE that transmitted the second discovery message.

[0026] Alternatively, based on the transmission of the third discovery message, the first relay UE may trigger a radio resource control (RRC) connection establishment process with the BS.

[0027] Alternatively, the second discovery message can be received from a second relay UE whose signal strength against the BS is greater than or equal to a preset threshold, and the second discovery message may include the user information identifier of the second relay UE and the user information identifier of the first relay UE.

[0028] According to another aspect, a non-transitory computer-readable recording medium for storing a program for performing the above-described methods can be provided.

[0029] According to another aspect, a first relay UE for performing the above method can be provided.

[0030] According to another aspect, a processing apparatus for controlling a first relay UE to perform the above-described method can be provided.

[0031] According to another aspect, a method performed by a second relay UE may include: receiving a first discovery message; and receiving and transmitting a second discovery message based on the first discovery message. The first discovery message may include a hop count configured to indicate that a hop count associated with a multi-hop U2N relay has not been specified.

[0032] According to another aspect, a second relay UE for performing the above method can be provided.

[0033] Beneficial effects

[0034] According to embodiments of this disclosure, multi-hop-based U2N relay communication can be performed more accurately and efficiently in wireless communication systems.

[0035] The effects to be achieved by the implementation methods are not limited to those specifically described above, and other effects not mentioned herein will be more clearly understood by those skilled in the art from the following detailed description. Attached Figure Description

[0036] Embodiments of this disclosure are illustrated in the accompanying drawings, which are incorporated in and constitute a part of this application, and together with the description, serve to explain the principles of this disclosure.

[0037] Figure 1 This diagram is used to illustrate the difference between RAT-based V2X communication prior to NR and NR-based V2X communication.

[0038] Figure 2 The structure of an LTE system with applicable implementation methods is illustrated.

[0039] Figure 3 The structure of an NR system according to an applicable implementation is illustrated.

[0040] Figure 4 The structure of an NR radio frame applicable to the implementation method is illustrated.

[0041] Figure 5 The time slot structure of an NR frame applicable to this implementation is illustrated.

[0042] Figure 6 An example of a communication structure available in a sixth-generation (6G) system according to an embodiment of the present disclosure is illustrated.

[0043] Figure 7 An electromagnetic spectrum according to an embodiment of the present disclosure is illustrated.

[0044] Figure 8 An example of a radio protocol architecture for SL communication is given.

[0045] Figure 9 The example illustrates a user equipment (UE) performing V2X or SL communication.

[0046] Figure 10 Examples of resource units for V2X or SL communication are shown.

[0047] Figure 11 An example of a BWP based on an embodiment of this disclosure is shown.

[0048] Figure 12 This illustrates the process by which a UE performs V2X or SL communication based on the transmission mode.

[0049] Figure 13 This is a diagram used to explain the control plane procedures of L2 U2N relay (UE to network relay).

[0050] Figure 14 This is a diagram used to explain multi-hop-based U2N relay communication.

[0051] Figure 15 This is a diagram illustrating the method by which a discovery message is sent by a first relay UE.

[0052] Figure 16 This is a diagram illustrating the method by which a second relay UE receives a discovery message.

[0053] Figure 17 A communication system applied to this disclosure is shown.

[0054] Figure 18 A wireless device applicable to this disclosure is shown.

[0055] Figure 19 Another example of a wireless device that applies the present disclosure is shown.

[0056] Figure 20 The vehicle or autonomous vehicle used in this disclosure is shown. Detailed Implementation

[0057] Wireless communication systems are multiple access systems that support communication with multiple users by sharing available system resources (e.g., bandwidth, transmission power, etc.). Examples of multiple access systems include Code Division Multiple Access (CDMA) systems, Frequency Division Multiple Access (FDMA) systems, Time Division Multiple Access (TDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single-Carrier Frequency Division Multiple Access (SC-FDMA) systems, Multi-Carrier Frequency Division Multiple Access (MC-FDMA) systems, and so on.

[0058] Sidelinks refer to communication schemes that establish direct links between user equipment (UEs) to enable direct exchange of voice or data between UEs without assistance from a base station (BS). Sidelinks are considered a way to address the burden on the BS caused by rapidly increasing data traffic.

[0059] Vehicle-to-everything (V2X) refers to a communication technology that allows vehicles to exchange information with other vehicles, pedestrians, and infrastructure entities via wired / wireless communication. V2X can be categorized into four types: vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-network (V2N), and vehicle-to-pedestrian (V2P). V2X communication can be provided through PC5 interfaces and / or Uu interfaces.

[0060] As more and more communication devices require greater communication capacity when sending and receiving signals, there is a need for improved mobile broadband communications compared to traditional radio access technologies. Therefore, communication systems considering service / UE sensitivity to reliability and latency are being discussed. Next-generation radio access technologies that incorporate enhanced mobile broadband communications, massive MTC, and ultra-reliable and low-latency communications (URLLC) can be referred to as new radio access technologies (RAT) or new radio (NR). Even within NR, V2X communication can be supported.

[0061] The technologies described in this article can be used in various radio access systems such as Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Orthogonal Frequency Division Multiple Access (OFDMA), and Single Carrier Frequency Division Multiple Access (SC-FDMA). CDMA can be implemented as radio technologies such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can be implemented as radio technologies such as Global System for Mobile Communications (GSM), Universal Packet Radio Service (GPRS), and Enhanced Data Rate for GSM Evolution (EDGE). OFDMA can be implemented as radio technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, and Evolved UTRA (E-UTRA). UTRA is part of the Universal Mobile Telecommunications System (UMTS). The 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is part of Evolved UMTS (E-UMTS) that uses Evolved UTRA (E-UTRA). 3GPP LTE uses OFDMA for downlink and SC-FDMA for uplink. LTE-A is an evolution of 3GPP LTE. 3GPP NR (New Radio or New Radio Access Technology) is an evolution of 3GPP LTE / LTE-A / LTE-A pro.

[0062] 5G NR is the successor to LTE-A and is a new type of clean-state mobile communication system characterized by high performance, low latency, and high availability. 5G NR can use all available spectrum resources, from low-frequency bands below 1 GHz to mid-frequency bands from 1 GHz to 10 GHz and high-frequency (millimeter wave) bands above 24 GHz.

[0063] For clarity, the description primarily focuses on LTE-A or 5G NR, but the technical spirit of the implementation is not limited thereto.

[0064] Figure 2 An example of an LTE system architecture that can be applied using this disclosure is illustrated. This may also be referred to as an evolved UMTS terrestrial radio access network (E-UTRAN) or an LTE / LTE-A system.

[0065] Reference Figure 2E-UTRAN includes an evolved Node B (eNB) 20 that provides the control plane and user plane to UE 10. UE 10 can be fixed or mobile and can also be referred to as a mobile station (MS), user terminal (UT), subscriber station (SS), mobile terminal (MT), or radio device. eNB 20 is a fixed station that communicates with UE 10 and can also be referred to as a base station (BS), base transceiver system (BTS), or access point.

[0066] The eNB 20 can connect to each other via the X2 interface. The eNB 20 connects to the evolved packet core (EPC) 39 via the S1 interface. More specifically, the eNB 20 connects to the mobility management entity (MME) via the S1-MME interface and to the serving gateway (S-GW) via the S1-U interface.

[0067] EPC 30 includes an MME, an S-GW, and a Packet Data Network Gateway (P-GW). The MME contains access or capability information about the UE and is primarily used for UE mobility management. The S-GW is a gateway with E-UTRAN as its endpoint, and the P-GW is a gateway with Packet Data Network (PDN) as its endpoint.

[0068] Based on the lowest three layers of the Open Systems Interconnection (OSI) reference model known in communication systems, the radio protocol stack between the UE and the network can be divided into Layer 1 (L1), Layer 2 (L2), and Layer 3 (L3). These layers are defined in pairs between the UE and the evolved UTRAN (E-UTRAN) for data transmission via the Uu interface. The Physical (PHY) layer at L1 provides information delivery services on the physical channel. The Radio Resource Control (RRC) layer at L3 is used to control radio resources between the UE and the network. For this purpose, the RRC layer exchanges RRC messages between the UE and the eNB.

[0069] Figure 3 The structure of an NR system to which this disclosure can be applied is illustrated.

[0070] Reference Figure 3 Next-generation radio access networks (NG-RAN) can include next-generation Node Bs (gNBs) and / or eNBs that provide user plane and control plane protocols to UEs. Figure 3 In this example, NG-RAN is shown as consisting only of gNBs. gNBs and eNBs are connected to each other via the Xn interface. gNBs and eNBs are connected to the 5G core network (5GC) via the NG interface. More specifically, gNBs and eNBs are connected to the Access and Mobility Management Function (AMF) via the NG-C interface and to the User Plane Function (UPF) via the NG-U interface.

[0071] Figure 4 The structure of an NR radio frame to which this disclosure can be applied is illustrated.

[0072] Reference Figure 4 Radio frames can be used for UL and DL transmissions in NR. A radio frame is 10ms long and can be defined by two 5ms half-frames. HF can include five 1ms subframes. Subframes can be divided into one or more time slots, and the number of time slots in SF can be determined based on the subcarrier spacing (SCS). Each time slot can include 12 or 14 OFDM (A) symbols depending on the cyclic prefix (CP).

[0073] In the normal CP (NCP) scenario, each time slot can include 14 symbols, while in the extended CP (ECP) scenario, each time slot can include 12 symbols. In this paper, symbols can be OFDM symbols (or CP-OFDM symbols) or SC-FDMA symbols (or DFT-s-OFDM symbols).

[0074] Table 1 below lists the number of symbols N per slot in the NCP case based on the SCS configuration μ. slot symb Number of time slots per frame N frame,u slot and the number of time slots in each subframe N subframe,u slot。

[0075] [Table 1]

[0076] Table 2 below lists the number of symbols per slot, the number of slots per frame, and the number of slots per subframe in the case of ECP, according to SCS.

[0077] [Table 2]

[0078] In NR systems, different OFDM(A) parameter sets (e.g., SCS, CP length, etc.) can be configured for multiple cells aggregated for a UE. Therefore, the (absolute time) duration of time resources (e.g., subframes, slots, or TTIs) comprising the same number of symbols (for convenience, time resources are collectively referred to as time units (TUs)) can be configured to be different for the aggregated cells.

[0079] In NR, various parameter sets or SCSs can be supported to support a wide range of 5G services. For example, using a 15kHz SCS can support wide areas in traditional cellular bands, while using a 30kHz / 60kHz SCS can support dense urban areas, lower latency, and wider carrier bandwidth. When the SCS is 60kHz or higher, bandwidths wider than 24.25GHz can be supported to overcome phase noise.

[0080] NR bands can be defined as two types of frequency ranges. These two types of frequency ranges can be FR1 and FR2. The numerical values ​​of the frequency ranges can be changed. For example, the two types of frequency ranges can be configured as shown in Table 3 below. In the frequency ranges used in NR systems, FR1 can represent "the range below 6 GHz," and FR2 can represent "the range above 6 GHz," and can be referred to as millimeter wave (mmW).

[0081] [Table 3]

[0082] As mentioned above, the frequency range of the NR system can be varied. For example, as shown in Table 4 below, FR1 can include a frequency band from 410MHz to 7125MHz. That is, FR1 can include a frequency band of 6GHz (or 5850MHz, 5900MHz, 5925MHz, etc.) or higher. For example, the 6GHz (or 5850MHz, 5900MHz, 5925MHz, etc.) or higher frequency band included in FR1 can include unlicensed frequency bands. Unlicensed frequency bands can be used for various purposes, such as for vehicle (e.g., autonomous driving) communications.

[0083] [Table 4]

[0084] Figure 5 The time slot structure of the NR frame to which this disclosure can be applied is illustrated.

[0085] Reference Figure 5 A time slot includes multiple symbols in the time domain. For example, a time slot may include 14 symbols in normal CP and 12 symbols in extended CP. Alternatively, a time slot may include 7 symbols in normal CP and 6 symbols in extended CP.

[0086] A carrier can comprise multiple subcarriers in the frequency domain. A resource block (RB) is defined as multiple consecutive subcarriers in the frequency domain (e.g., 12 subcarriers). A bandwidth portion (BWP) can be defined as multiple consecutive (P) RBs in the frequency domain, and a BWP can correspond to a set of parameters (e.g., SCS, CP length, etc.). A carrier can comprise up to N (e.g., 5) BWPs. Data communication can be performed within an active BWP. In the resource grid, each element can be called a resource element (RE) and can be mapped to a complex symbol.

[0087] The radio interface between UEs or between a UE and the network can consist of layers L1, L2, and L3. In various embodiments of this disclosure, layer L1 can represent the physical layer. Layer L2 can, for example, represent at least one of the MAC layer, RLC layer, PDCP layer, and SDAP layer. Layer L3 can, for example, represent the RRC layer.

[0088] Figure 6 An example of a communication structure that can be used in a sixth-generation (6G) system according to an embodiment of the present disclosure is illustrated. Figure 6 The implementation methods can be combined with various implementation methods of this disclosure.

[0089] In 6G, new network features may include the following.

[0090] - Integrated satellite network

[0091] - Connected Intelligence: Compared to previous generations of wireless communication systems, 6G can update the development of wireless from "Internet of Everything" to "Intelligent Internet of Everything". Artificial intelligence (AI) can be applied to every step of the communication process (i.e., every step of signal processing, which will be described later).

[0092] - Seamless integration of wireless information and power transfer

[0093] - Ubiquitous Ultra-3D Connectivity: Ubiquitous ultra-3D connectivity can be achieved in 6G through access to networks and core networks via drones and ultra-low Earth orbit satellites.

[0094] Regarding the new 6G network features described above, some general requirements may include the following: - Small Cellular Network - Ultra-dense heterogeneous networks - High-capacity backhaul - Radar technology integrated with mobile technology: High-precision positioning (or location-based services) via communication is one of the functions of 6G wireless communication systems. Therefore, radar systems will be integrated with 6G networks.

[0095] - Softwareization and Virtualization

[0096] The key implementation technologies of 6G systems will be described below.

[0097] - Artificial Intelligence (AI): Introducing AI into communications can simplify and enhance real-time data transmission. AI can use extensive analytics to determine how to perform complex tasks. In other words, AI can improve efficiency and reduce processing latency. Time-consuming tasks such as handover, network selection, and resource scheduling can be performed instantly using AI. AI can also play a crucial role in machine-to-machine (M2M), machine-to-human, and human-to-machine communications. Furthermore, AI can enable rapid communication in brain-computer interfaces (BCIs). AI-based communication systems can be supported by metamaterials, intelligent architectures, intelligent networks, intelligent devices, intelligent cognitive radios, self-sustaining wireless networks, and machine learning.

[0098] Terahertz (THz) Communication: Increasing bandwidth can improve data transmission rates, which can be achieved by using wide-bandwidth sub-THz communication and applying advanced massive MIMO technology. THz waves, also known as submillimeter radiation, typically represent the frequency band between 0.1 THz and 10 THz, corresponding to wavelengths in the range of 0.03 mm to 3 mm. The 100 GHz to 300 GHz band (sub-THz band) is considered the main part of the THz band for cellular communication. Adding the sub-THz band to the millimeter-wave band can increase the capacity of 6G cellular communication. The 300 GHz to 3 THz band within the defined THz band falls into the far-infrared (IR) band. While the 300 GHz to 3 THz band is part of the optical band, it lies at the boundary of the optical band and is immediately following the RF band. Therefore, the 300 GHz to 3 THz band exhibits similarities to RF.

[0099] Figure 7 An electromagnetic spectrum according to an embodiment of the present disclosure is illustrated. Figure 7 The implementation methods can be combined with various embodiments of this disclosure. Key features of THz communication include: (i) a wide available bandwidth supporting extremely high data transmission rates, and (ii) high path loss at high frequencies (highly directional antennas are indispensable). The narrow beamwidth produced by highly directional antennas can reduce interference. The small wavelength of THz signals allows for the integration of a greater number of antenna elements in devices and base stations operating in this frequency band. This enables the use of advanced adaptive array techniques that overcome distance limitations.

[0100] - Massive MIMO technology

[0101] - Holographic Beamforming (HBF)

[0102] - Optical wireless technology

[0103] - Free Space Optics (FSO) Backhaul Network

[0104] - Quantum communication

[0105] - Cellular communication

[0106] - Integration of wireless information and power transmission

[0107] - Integration of wireless communication and sensing

[0108] - Integrated access and backhaul networks

[0109] Big Data Analytics

[0110] - Reconfigurable smart surfaces

[0111] - Metaverse

[0112] - Blockchain

[0113] - Unmanned Aerial Vehicles (UAVs): Unmanned aerial vehicles, or drones, will be a key element in 6G wireless communication. In many situations, UAV technology can be used to provide high-data-rate wireless connectivity. Base station entities (BSs) can be mounted on UAVs to provide cellular connectivity. UAVs can possess specific capabilities not found in fixed base station infrastructure, such as easy deployment, stable line-of-sight links, and the freedom of controlled mobility. During emergencies such as natural disasters, the deployment of terrestrial communication infrastructure may be economically infeasible and sometimes unable to provide service in volatile environments. UAVs can easily handle such situations. UAVs will become a new paradigm in wireless communication. This technology helps meet the three basic requirements of wireless networks: enhanced mobile broadband (eMBB), ultra-reliable ultra-low latency communication (URLLC), and massive machine-type communication (mMTC). Furthermore, UAVs can support a variety of applications, such as improving network connectivity, fire detection, disaster emergency services, security and surveillance, pollution monitoring, parking monitoring, and accident monitoring. Therefore, UAV technology is considered one of the most important technologies in 6G communication.

[0114] - Autonomous Driving (Driverless): Vehicle-to-Everything (V2X) communication is a key element in establishing the infrastructure for autonomous driving. It refers to technologies that allow vehicles to communicate and share information with various elements on the road, such as vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) wireless communication. To maximize the performance of autonomous driving and ensure high safety standards, fast transmission speeds and low latency technologies are indispensable. Furthermore, future autonomous driving will involve not only providing warnings or guidance messages to drivers but also active intervention in vehicle operation and direct control of vehicles in dangerous situations. To accommodate the massive amounts of information that need to be sent and received, 6G is expected to achieve faster transmission speeds and lower latency compared to 5G, thereby maximizing autonomous driving capabilities.

[0115] Figure 8 An example is illustrated of a radio protocol architecture for SL communication to which this disclosure can be applied. Specifically, Figure 8 (a) shows the NR user plane protocol stack, and Figure 8 (b) shows the NR control plane protocol stack.

[0116] The following text will describe the side link synchronization signal (SLSS) and synchronization information.

[0117] SLSS is a sequence specific to SL and can include a primary sidelink synchronization signal (PSSS) and a secondary sidelink synchronization signal (SSSS). PSSS can be referred to as the primary sidelink synchronization signal (S-PSS), and SSSS can be referred to as the secondary sidelink synchronization signal (S-SSS). For example, a 127-bit M sequence can be used for S-PSS, and a 127-bit Gold sequence can be used for S-SSS. For example, a UE can use S-PSS to detect the initial signal and obtain synchronization. For example, a UE can use S-PSS and S-SSS to obtain fine synchronization and can detect the synchronization signal ID.

[0118] The Physical Sidelink Broadcast Channel (PSBCH) can be a (broadcast) channel used to transmit basic (system) information that the UE needs to know before transmitting and receiving SL signals. For example, basic information may include SLSS-related information, duplex mode (DM), time-division duplex uplink / downlink (TDD UL / DL) configuration, resource pool-related information, the type of application associated with the SLSS, subframe offset, and broadcast information. For example, to evaluate PSBCH performance in NR V2X, the PSBCH payload size can be 56 bits, including a 24-bit CRC.

[0119] S-PSS, S-SSS, and PSBCH can be included in a block format that supports periodic transmission (e.g., the SL synchronization signal (SS) / PSBCH block, hereinafter referred to as the sidelink synchronization signal block (S-SSB)). The S-SSB can have the same set of parameters (i.e., SCS and CP lengths) as the Physical Sidelink Control Channel (PSCCH) / Physical Sidelink Shared Channel (PSSCH) in the carrier, and its transmission bandwidth can be within a (pre-)defined SL BWP. For example, the bandwidth of the S-SSB can be 11 resource blocks (RBs). Similarly, the PSBCH can span 11 RBs. The frequency location of the S-SSB can be (pre-)defined. Accordingly, the UE does not need to perform hypothesis detection on the frequency in the carrier to discover the S-SSB.

[0120] In an NR SL system, multiple parameter sets with different SCS and / or CP lengths can be supported. In this case, as the SCS increases, the length of time resources for the transmitting UE to transmit S-SSBs can be shortened. Therefore, the coverage of S-SSBs can be narrowed. Accordingly, to ensure S-SSB coverage, the transmitting UE can transmit one or more S-SSBs to the receiving UE within an S-SSB transmission period, depending on the SCS. For example, the number of S-SSBs transmitted by the transmitting UE to the receiving UE within an S-SSB transmission period can be pre-configured or configured for the transmitting UE. For example, the S-SSB transmission period can be 160ms. For example, a 160ms S-SSB transmission period can be supported for all SCSs.

[0121] For example, when the SCS is 15kHz in FR1, the transmitting UE can send one or two S-SSBs to the receiving UE within one S-SSB transmission period. For example, when the SCS is 30kHz in FR1, the transmitting UE can send one or two S-SSBs to the receiving UE within one S-SSB transmission period. For example, when the SCS is 60kHz in FR1, the transmitting UE can send one, two, or four S-SSBs to the receiving UE within one S-SSB transmission period.

[0122] For example, when the SCS is 60kHz in FR2, the transmitting UE can send 1, 2, 4, 8, 16, or 32 S-SSBs to the receiving UE within one S-SSB transmission period. For example, when the SCS is 120kHz in FR2, the transmitting UE can send 1, 2, 4, 8, 16, 32, or 64 S-SSBs to the receiving UE within one S-SSB transmission period.

[0123] When the SCS is 60kHz, two types of CP can be supported. Furthermore, the structure of the S-SSB transmitted from the transmitting UE to the receiving UE can depend on the CP type. For example, the CP type can be Normal CP (NCP) or Extended CP (ECP). Specifically, for example, when the CP type is NCP, the number of symbols to which the PSBCH in the S-SSB transmitted by the transmitting UE is mapped can be 9 or 8. On the other hand, for example, when the CP type is ECP, the number of symbols to which the PSBCH in the S-SSB transmitted by the transmitting UE is mapped can be 7 or 6. For example, the PSBCH can be mapped to the first symbol in the S-SSB transmitted by the transmitting UE. For example, upon receiving an S-SSB, the receiving UE can perform Automatic Gain Control (AGC) operation during the time period corresponding to the first symbol of the S-SSB.

[0124] Figure 9 Examples of UEs that can perform V2X or SL communications using this disclosure are shown.

[0125] Reference Figure 9 In V2X or SL communication, the term UE can primarily refer to the user's UE. However, a BS can also be considered a UE when a network device, such as a BS, sends and receives signals according to a communication scheme between UEs. For example, UE 1 can be a first device 100, and UE 2 can be a second device 200.

[0126] For example, UE 1 can select a resource element corresponding to a specific resource from a resource pool (which represents a set of resources). UE 1 can then transmit an SL signal through that resource element. For example, UE 2, as a receiving UE, can receive the configuration of the resource pool in which UE 1 can transmit signals, and can detect UE 1's signals within that resource pool.

[0127] Here, when UE1 is within the BS's connection range, the BS can notify UE1 of the resource pool. On the other hand, when UE1 is outside the BS's connection range, another UE can notify UE1 of the resource pool, or UE1 can use a pre-configured resource pool.

[0128] Typically, a resource pool can consist of multiple resource units, and each UE can select one or more resource units and send SL signals through the selected units.

[0129] Figure 10 Examples of resource units for V2X or SL communication that can be applied to this disclosure are shown.

[0130] Reference Figure 10The frequency resources in the resource pool can be divided into NF sets, and the time resources in the resource pool can be divided into NT sets. Therefore, a total of NF sets can be defined in the resource pool. NT resource units. Figure 10 An exemplary case of a periodically repeating resource pool with NT subframes is shown.

[0131] like Figure 10 As shown, a resource unit (e.g., unit #0) can appear periodically and repeatedly. Alternatively, to achieve diversity effects in the time or frequency dimension, the index of the physical resource unit to which a logical resource unit is mapped can change over time in a predetermined pattern. In this structure of resource units, a resource pool can represent the set of resource units available to a UE intended to transmit SL signals.

[0132] Resource pools can be further subdivided into several types. For example, based on the content of the SL signals sent in each resource pool, resource pools can be divided as follows.

[0133] (1) Scheduling assignment (SA) can be a signal that includes information such as the location of the resources through which the UE transmits SL data channels, the modulation and coding scheme (MCS) or multiple-input multiple-output (MIMO) transmission scheme required to demodulate other data channels, and timing advance (TA). SA can be multiplexed with SL data and transmitted through the same resource element. In this case, the SA resource pool can represent the resource pool where SA and SL data are multiplexed and transmitted. SA can be referred to as the SL control channel.

[0134] (2) The SL data channel (Physical Side Link Shared Channel (PSSCH)) can be a resource pool through which the transmitting UE transmits user data. When SA and SL data are multiplexed and transmitted together in the same resource element, only the SL data channel other than the SA information can be transmitted in the resource pool for the SL data channel. In other words, the resource element (RE) used to transmit SA information in a separate resource element in the SA resource pool can still be used to transmit SL data in the resource pool for the SL data channel. For example, the transmitting UE can map the PSSCH to consecutive PRBs and transmit them.

[0135] (3) The discovery channel can be a resource pool used by the transmitting UE to send information such as its ID. Through this channel, the transmitting UE can allow neighboring UEs to discover the transmitting UE.

[0136] Even if the aforementioned SL signals have the same content, they can use different resource pools based on the transmission / reception characteristics of the SL signals. For example, even if the SL data channel or discovery message is the same in the signal, it can be classified into different resource pools based on the determination of the SL signal transmission timing (e.g., transmission at the reception time of the synchronization reference signal or transmission by applying a predetermined TA at the reception time), resource allocation scheme (e.g., the BS assigns separate signal transmission resources to a separate transmitting UE, or a separate transmitting UE selects a separate signal transmission resource within the resource pool), signal format (e.g., by the number of symbols occupied by each SL signal in a subframe, or the number of subframes used for the transmission of an SL signal), signal strength from the BS, transmission power strength of the SL UE, etc.

[0137] Figure 11 An example of a BWP based on an embodiment of this disclosure is shown. Figure 11 The implementation methods can be combined with various implementation methods of this disclosure. Figure 11 In this implementation, it is assumed that the number of BWPs is 3.

[0138] Reference Figure 11 A common resource block (CRB) can be a carrier resource block numbered from one end of a carrier frequency band to the other. Alternatively, a PRB can be a resource block numbered within each BWP. Point A can indicate a common reference point for the resource block grid.

[0139] BWP can be determined by point A and its offset N from point A. start BWP and bandwidth N size BWP Configuration. For example, point A could be an external reference point for the PRB of a subcarrier 0-aligned carrier for all parameter sets (e.g., all parameter sets supported by the network on that carrier). For example, offset could be the PRB spacing between the lowest subcarrier in a given parameter set and point A. For example, bandwidth could be the number of PRBs in a given parameter set.

[0140] The following describes V2X or SL communication. SLSS is an SL-specific sequence and can include a primary sidelink synchronization signal (PSSS) and a secondary sidelink synchronization signal (SSSS). PSSS can be referred to as the primary sidelink synchronization signal (S-PSS), and SSSS can be referred to as the secondary sidelink synchronization signal (S-SSS). For example, a 127-character M sequence can be used for S-PSS, and a 127-character Gold sequence can be used for S-SSS. For example, a UE can use S-PSS to detect the initial signal and obtain synchronization. For example, a UE can use S-PSS and S-SSS to obtain fine synchronization and can detect the synchronization signal ID.

[0141] The Physical Sidelink Broadcast Channel (PSBCH) can be a (broadcast) channel used to transmit basic (system) information that the UE needs to know before transmitting and receiving SL signals. For example, basic information may include SLSS-related information, duplex mode (DM), time-division duplex uplink / downlink (TDD UL / DL) configuration, resource pool-related information, the type of application associated with the SLSS, subframe offset, and broadcast information. For example, to evaluate PSBCH performance in NR V2X, the PSBCH payload size can be 56 bits, including a 24-bit CRC.

[0142] S-PSS, S-SSS, and PSBCH can be included in a block format that supports periodic transmission (e.g., the SL synchronization signal (SS) / PSBCH block, hereinafter referred to as the sidelink synchronization signal block (S-SSB)). The S-SSB can have the same set of parameters (i.e., SCS and CP lengths) as the Physical Sidelink Control Channel (PSCCH) / Physical Sidelink Shared Channel (PSSCH) in the carrier, and its transmission bandwidth can be within a (pre-)defined SL BWP. For example, the bandwidth of the S-SSB can be 11 resource blocks (RBs). Similarly, the PSBCH can span 11 RBs. The frequency location of the S-SSB can be (pre-)defined. Accordingly, the UE does not need to perform hypothesis detection on the frequency in the carrier to discover the S-SSB.

[0143] Figure 12 An example is illustrated of a terminal performing V2X or SL communication according to a resource allocation mode in accordance with an embodiment of the present disclosure. Figure 12 The implementation methods can be combined with various implementation methods of this disclosure.

[0144] Reference Figure 12 In step (a), under LTE transmission mode 1, LTE transmission mode 3, or NR resource allocation mode 1, the BS can schedule SL resources to be used by the UE for SL transmission. For example, in step S1200, the base station can send information associated with SL resources and / or information associated with UL resources to the first terminal. For example, UL resources may include PUCCH resources and / or PUSCH resources. For example, UL resources may be resources used to report SL HARQ feedback to the base station.

[0145] For example, the first UE can receive information related to Dynamic Grant (DG) resources and / or Configuration Grant (CG) resources from the base station. For example, CG resources may include CG Type 1 resources or CG Type 2 resources. In this disclosure, DG resources can be resources configured / allocated to the first UE by the base station via Downlink Control Information (DCI). In this disclosure, CG resources can be (periodic) resources configured / allocated to the first UE by the base station via DCI and / or RRC messages. For example, in the case of CG Type 1 resources, the base station can send an RRC message to the first UE including information related to the CG resources. For example, in the case of CG Type 2 resources, the base station can send an RRC message to the first UE including information related to the CG resources, and the base station can send a DCI message to the first UE related to the activation or release of the CG resources.

[0146] In step S1510, the first UE may send a PSCCH (e.g., Side Link Control Information (SCI) or Level 1 SCI) to the second UE based on resource scheduling. In step S1220, the first UE may send a PSSCH related to the PSCCH (e.g., Level 2 SCI, MAC PDU, data, etc.) to the second UE. In step S1230, the first UE may receive a PSFCH related to the PSCCH / PSSCH from the second UE. For example, it may receive HARQ feedback information (e.g., NACK or ACK information) from the second UE via the PSFCH. In step S1240, the first UE may send / report HARQ feedback information to the base station via PUCCH or PUSCH. For example, the HARQ feedback information reported to the base station may be information generated by the first UE based on the HARQ feedback information received from the second UE. For example, the HARQ feedback information reported to the base station may be information generated by the first UE based on pre-configured rules. For example, the DCI may be a DCI used for SL scheduling.

[0147] Reference Figure 12(b) In LTE transmission mode 2, LTE transmission mode 4, or NR resource allocation mode 2, the UE can determine the SL transmission resource within the SL resources configured by the base station / network or the pre-configured SL resource. For example, the configured SL resource or the pre-configured SL resource can be a resource pool. For example, the UE can autonomously select or schedule resources for SL transmission. For example, the UE can perform SL communication by autonomously selecting resources within the configured resource pool. For example, the UE can autonomously select resources within the selection window by performing a sensing process and a resource (re)selection process. For example, sensing can be performed on a sub-channel basis. For example, in step S1210, the first UE, which has selected resources in the resource pool, can use those resources to send a PSCCH (e.g., Side Link Control Information (SCI) or Level 1 SCI) to the second UE. In step S1220, the first UE can send a PSSCH (e.g., Level 2 SCI, MAC PDU, data, etc.) related to the PSCCH to the second UE. In step S1230, the first UE can receive a PSFCH related to the PSCCH / PSSCH from the second UE.

[0148] Reference Figure 12 In (a) or (b), for example, the first UE may send an SCI to the second UE via PSCCH. Alternatively, for example, the first UE may send two consecutive SCIs (e.g., level 2 SCIs) to the second UE via PSCCH and / or PSSCH. In this case, the second UE may decode the two consecutive SCIs (e.g., level 2 SCIs) to receive the PSSCH from the first UE. In this disclosure, an SCI sent via PSCCH may be referred to as the first SCI, first SCI, level 1 SCI, or level 1 SCI format, and an SCI sent via PSSCH may be referred to as the second SCI, second SCI, level 2 SCI, or level 2 SCI format.

[0149] Reference Figure 12 In step (a) or (b), the first terminal may receive the PSFCH. For example, the first terminal and the second terminal may determine the PSFCH resource, and the second terminal may use the PSFCH resource to send HARQ feedback to the first terminal.

[0150] Reference Figure 12 In step (a), the first terminal may send SL HARQ feedback to the base station via PUCCH and / or PUSCH in step S1540.

[0151] Figure 13 This is a diagram used to explain the control plane procedures of L2 U2N relay (UE to network relay).

[0152] Regarding PC5-RRC in Rel-16 NR V2X, the PC5 unicast link establishment process can be reused before a remote UE establishes a Uu RRC connection with the network via a relay UE to establish a secure unicast link between the remote UE and the relay UE used for Layer 2 UE-to-network (L2 U2N) relay.

[0153] When a remote UE initiates its first RRC message to establish a connection with the gNB, whether within or outside coverage, the PC5 L2 configuration transmitted between the remote UE and the U2N relay UE can be based on the Radio Link Control (RLC) and / or Media Access Control (MAC) configurations defined in the standard. To establish Uu signaling radio bearer 1 / signaling radio bearer 2 (SRB1 / SRB2) and DRB, the remote UE follows the conventional Uu configuration procedure for L2 U2N relays.

[0154] The specific scenario (TS 38.300) describes the control plane procedures for L2 U2N relays.

[0155] In step S1300, the remote UE and the relay UE can perform a discovery procedure. In step S1301, the remote UE and the relay UE can establish a PC5-RRC connection based on the conventional Rel-16 procedure.

[0156] In step S1302, the remote UE can send a first RRC message (i.e., RRCSetupRequest) using the default PC5 L2 configuration to establish a connection with the gNB via the relay UE. The gNB responds to the remote UE with an RRCSetup message (S1303). The default PC5 configuration is used to send the RRCSetup message to the remote UE. If the relay UE has not yet started in the RRC_CONNECTED state, the relay UE needs to establish the connection upon receiving the message about the default PC5 L2 configuration.

[0157] In step S1304, the gNB and the relay UE perform a relay channel establishment procedure via Uu. Depending on the gNB configuration, the relay / remote UE establishes an RLC channel for relaying SRB1 to the remote UE via PC5. This step prepares the relay channel for SRB1.

[0158] In step S1305, an SRB1 message (e.g., an RRCSetupComplete message) from the remote UE is sent to the gNB via the relay UE on the SRB1 relay channel through PC5. The remote UE establishes an RRC connection via Uu.

[0159] In steps S1306 and S1307, the remote UE and gNB establish security according to the conventional procedure, and the security message is sent through the relay UE.

[0160] In steps S1308 and S1309, the gNB sends an RRCReconfiguration message to the remote UE via the relay UE to establish an SRB2 / DRB for relaying. The remote UE responds to the gNB via an RRCReconfigurationComplete message from the relay UE.

[0161] In step S1310, the gNB establishes an additional RLC channel for service relay between the gNB and the relay UE. Depending on the gNB configuration, the relay / remote UE establishes an additional RLC channel for service relay between the remote UE and the relay UE.

[0162] For L2 U2N trunks, in addition to the connection establishment process: - The RRC rebuild and RRC connection release processes can reuse traditional RRC procedures, along with message content / configuration design, which will be determined during the WI phase.

[0163] - The RRC connection reconstruction and RRC connection restoration processes can reuse the traditional RRC process as a baseline by considering the connection establishment process of the L2 U2N trunk described above to handle the trunk-specific portion and message content / configuration design. The message content / configuration can be defined at a later stage.

[0164] For the discovery process, discovery model A and discovery model B can be defined. Discovery model A can be a scheme in which a relay UE periodically broadcasts an announcement message indicating its presence. Discovery model B can be a scheme in which a device intending to perform relay communication (i.e., a remote UE) periodically broadcasts a solicitation message requesting relay communication. (See 3GPP TS 23.304.)

[0165] During the discovery process, the common identifier for a 5G ProSe UE to network relay can be as follows (see 3GPP TS23.304). The following parameters can be used in the 5G ProSe UE to network relay discovery announcement message (Model A). Here, the source layer 2 ID and destination layer 2 ID can be used to send and receive discovery messages, and the announcer information and relay service code can be included in the discovery message.

[0166] - Source Layer 2 ID: 5G ProSe UE to Network Relay can independently select the Source Layer 2 ID used for 5G ProSe UE to Network Relay discovery.

[0167] - Destination Layer 2 ID: This can be the destination Layer 2 ID selected for 5G ProSe UE to network relay discovery (see Clause 5.1.4.1 of 3GPP TS 23.304).

[0168] - Notifier information: Information about the notifier user can be provided (e.g., user information ID).

[0169] - Relay Service Code: This can be a parameter identifying the connection service provided by the 5G ProSe UE to the network relay to the 5G ProSe remote UE. The relay service code can be configured by the 5G ProSe UE to the network relay for advertising. Additionally, the relay service code can identify the user authorized to receive services from the 5G ProSe UE to the network relay and can be used to select relevant security policies or information required for authentication and authorization between the 5G ProSe remote UE and the 5G ProSe UE to the network relay (e.g., the relay service code for a relay used only by police officers may differ from the relay service code for a relay used only by firefighters. This could be to support internet access even if the relay potentially provides a connection to the same data network (DN)).

[0170] The following parameters can be used in 5G ProSe UE to network relay discovery solicitation messages (Model B). Here, the source layer 2 ID and destination layer 2 ID can be used to send and receive messages, and the discoverer information and relay service code can be included in the message.

[0171] - Source Layer 2 ID: 5G ProSe remote UEs can independently select the Source Layer 2 ID used for 5G ProSe UE to network relay discovery.

[0172] - Destination Layer 2 ID: The destination layer 2 ID used for 5G ProSe UE to network relay discovery can be selected based on a predetermined scenario (see Clause 5.1.4.1 of 3GPP TS 23.304).

[0173] - Discoverer information: This can provide information about the discoverer user (e.g., user information ID).

[0174] - Target information: Information about the user who discovered the target can be provided (e.g., user information ID).

[0175] - Relay Service Code: This can be information about connections that the discovering UE is interested in. The relay service code can be configured by a 5G ProSe remote UE interested in the relevant connection service.

[0176] The following parameters can be used in the 5G ProSe UE to network relay discovery response message (Model B). Here, the source layer 2 ID and destination layer 2 ID can be used to send and receive messages, and the discoverer information and relay service code can be included in the message.

[0177] - Source Layer 2 ID: 5G ProSe UE to Network Relay can independently select the Source Layer 2 ID used for 5G ProSe UE to Network Relay discovery.

[0178] - Destination Layer 2 ID: This can be set to the source Layer 2 ID of the received 5G ProSe UE to network relay discovery solicitation message.

[0179] - Relay Service Code: This identifies the connection service provided by the 5G ProSe UE to the 5G ProSe remote UE that matches the relay service code of the corresponding discovery solicitation message.

[0180] - Discoverer information: Information about the discoverer can be provided (e.g., user information ID).

[0181] The following parameters can be used in the relay discovery additional information message (Model A) according to the predetermined scenario for 5G ProSe UE to network relay (Section 6.5.1.3 of 3GPP TS 23.304). Here, the source layer 2 ID and destination layer 2 ID can be used to send and receive messages, and other parameters can be included in the message.

[0182] - Source Layer 2 ID: 5G ProSe UEs can autonomously select the Source Layer 2 ID used to send relay discovery additional information messages to network relays.

[0183] - Destination Layer 2 ID: The destination Layer 2 ID used to send relay discovery additional information messages can be selected based on the configuration defined in the predetermined scenario (Article 5.1.4.1 of 3GPP TS 23.304).

[0184] - Relay Service Code: This can be the relay service code associated with the message. The relay service code can be used to identify the security parameters required for the receiving UE to process the discovery message.

[0185] - Notifier Information: This provides information about the user who made the notification.

[0186] - Additional parameters: Additional parameters for 5G ProSe Layer 3 UE to network relay (if applicable) are defined in the predefined scenario (Article 5.8.3.2 of 3GPP TS 23.304).

[0187] The following section will describe in detail the method for performing multi-hop U2N relay communication based on the discovery model A described above.

[0188] Figure 14 This is a diagram used to explain multi-hop-based U2N relay communication.

[0189] In existing Rel-17 SL U2N relay operations, technological advancements have involved aspects such as <gnb>The connection relationship is between a relay UE and a remote UE. However, future multi-hop U2N relay operations may require technological advancements in the structure used to connect the gNB and the remote UE via multi-hop relay UEs. When using multi-hop relay UEs, a greater coverage extension can be achieved than in existing U2N scenarios.

[0190] The following describes methods for forwarding / broadcasting discovery messages under various circumstances during multi-hop (MP) U2N relay operation. In this context, broadcasting a discovery message may refer to, unlike simple forwarding, regenerating the relay UE's discovery message based on a discovery message received from another relay UE and sending the regenerated discovery message as a forwarding of the received discovery message. When the operation of broadcasting and / or forwarding a discovery message is initiated by another relay UE (e.g., by receiving a discovery message from another relay UE), the relay UE may perform the operation of modifying the hop count value of the received discovery message and broadcasting / forwarding that discovery message.

[0191] In the following text, for ease of description, such as Figure 14 As shown, a relay UE directly connected to the gNB is defined as relay UE1 (or the last relay UE), a relay UE connected to relay UE1 is defined as relay UE2 (or an intermediate relay UE), and another relay UE connected to relay UE2 is defined as relay UE3. Alternatively, relay UE1 can be defined as a Uu-SL relay UE, and relay UE2 and relay UE3 can be defined as SL-SL relay UEs.

[0192] Furthermore, the technical methods and elements required to apply the traditional discovery process based on discovery model A to multi-hop (MH) operations will be described in detail below.

[0193] Operational method of discovery model A for multi-hop U2N relay operations

[0194] When Model A is applied to MH operations, the following operational approach can be considered. As mentioned above, relay UE1 can be a relay UE capable of directly connecting to the gNB.

[0195] 1. Case where relay UE1 initiates the transmission of a discovery message.

[0196] Similar to the operation of Discovery Model A in Rel-17, the announcer information within the discovery message sent by Relay UE1 can indicate the User Info ID of Relay UE1. In this case, the sent discovery message can include a value (or indicator) directly indicating that the message was sent by a UE (or relay UE) capable of directly connecting to the gNB, or it can implicitly / implicationally indicate that the message was sent by a UE capable of directly connecting to the gNB via a hop count value (e.g., hop count "1" or "0"). Furthermore, the discovery message can include information indicating support for MH relay operation. This is to allow another relay / remote UE receiving the discovery message to identify that the corresponding relay UE supports MH relay operation, thereby performing additional multi-hop related operations.

[0197] For relay UE2 (e.g., an intermediate relay UE that cannot directly connect to the gNB (to a specific cell), the transmission of a discovery message can be triggered by the reception of a discovery message from relay UE1. In this case, the announcer information in the discovery message sent by relay UE2 can be the user information ID of relay UE2, and the hop count can be set to "2" (for convenience, the following description is based on the assumption that the hop count "1" is set / indicated in the discovery message sent by a relay UE that can directly connect to the gNB). Alternatively, the discovery message sent by relay UE2 may include information indicating that the message was triggered by the reception of a discovery message from another relay UE. Furthermore, the discovery message sent by relay UE2 may include the user information ID of relay UE1 and / or the hop count value of relay UE1. Even in this case, the discovery message sent by the relay UE may also include information indicating support for MH relay operation. For example, whether Rel-19 MH relay is supported can be implicitly indicated by a flag, or by a user information value (or hop count value) for the first hop. When a remote UE that can only support single-hop (SH) relay (e.g., a Rel-18 remote UE) receives a discovery message that includes information indicating multi-hop support, the remote UE may not select the relay UE associated with the discovery message.

[0198] When a relay UE2 receives a discovery message from another relay UE1' (e.g., another relay UE that can directly connect to the gNB, or a relay UE whose signal strength to the gNB is greater than or equal to a specific threshold), the discovery message sent / forwarded by relay UE2 may also include the user information ID of relay UE1'.

[0199] The transmission of a discovery message from relay UE2 can be triggered by the reception of discovery messages from relay UE1 and relay UE1'. In this case, relay UE2 can generate a discovery message corresponding to each of the discovery messages received from relay UE1 and relay UE1'. For example, upon receiving a discovery message from each of relay UE1 and relay UE1', relay UE2 can generate a discovery message based on the reception of the discovery message from relay UE1, and also generate a discovery message based on the reception of the discovery message from relay UE1'. Alternatively, upon receiving a discovery message from each of relay UE1 and relay UE1', relay UE2 can send a single discovery message including the user information ID of relay UE1, the user information ID of relay UE1', and even announcer information included in another previously received discovery message.

[0200] For relay UE2, the transmission of a discovery message can be triggered not only by receiving a discovery message from a relay UE capable of directly connecting to the gNB, but also by receiving a discovery message from another relay UE (e.g., a relay UE with a hop count value other than 1, or a relay UE that cannot directly connect to the gNB). In this case, relay UE2 can send a discovery message that includes a list of announcer information included in multiple received discovery messages. As mentioned above, when sending a discovery message that includes announcer information from multiple received discovery messages, the hop count values ​​set / included in the multiple discovery messages can be different. Accordingly, relay UE2 can send a discovery message by bundling the announcer information of previous hops based on hop counts (or by grouping / mapping the announcer information for each hop count). Alternatively, relay UE2 can send a discovery message that includes a list of information (e.g., announcer information) about accessible relay UEs of previous hops based on cell ID / gNB ID / service type.

[0201] Alternatively, when the relay UE receives a discovery message from another relay UE that includes a hop count with a value greater than (or equal to) the (maximum) count configured by the network (NW), the relay UE may not forward the received discovery message, or may filter out the generation / triggering of discovery message transmission caused by the reception of the discovery message.

[0202] Alternatively, when the hop count included in a discovery message received from another relay UE is greater than or equal to its own hop count value, the relay UE may not forward the discovery message, or may filter out the transmission of discovery messages caused by the reception of the discovery message. For example, the relay UE may only forward discovery messages that can maintain the minimum hop count value, or may trigger the transmission of discovery messages due to the receipt of discovery messages that can maintain the minimum hop count value.

[0203] Alternatively, when the relay UE sends a discovery message that includes information from a previous relay UE (e.g., user information ID), a timer may be needed to determine how long the information from the previous relay UE remains valid. This timer can be applied to a relay UE that has already received a discovery message from another relay UE. This is to allow the relay UE to determine how long the received discovery message or the user information included in the received discovery message remains valid when sending its own discovery message based on a discovery message received from another relay UE (including partial information from the received discovery message). For example, the timer can be started when a discovery message is received from another relay UE, and when the time configured for the timer expires, the relay UE may no longer include the received relay UE's user information in its discovery message. The (other / previous) relay UE that sent the discovery message can configure the timer value based on its own mobility and / or the QoS of its service, and can include the configured timer value in the discovery message.

[0204] Alternatively, the discovery message sent by the relay UE may include load information of the relay UE as the sending entity. For example, in MH operation, the load information of the previous relay UE may be transmitted via the discovery message, or the load information may be set as the maximum load value among the load values ​​of the previous relay UE as the representative value.

[0205] 2. Case where relay UE2 initiates the sending of a discovery message

[0206] Relay UE2 may be a relay UE that cannot directly connect to the gNB (e.g., an intermediate relay UE or a relay UE whose signal strength to the gNB is less than a preset threshold). In this case, relay UE2 may not be able to identify the number of hops required to reach / connect to the gNB. In this situation, relay UE2 may not know its own hop count value used for MH relay operations. Even in this case, relay UE2 can still initiate / trigger the transmission of a discovery message. For example, relay UE2 can determine its own hop count to be included in its discovery message through the following process.

[0207] (1) When the relay UE2 (directly) initiates the broadcast of the discovery message, the hop count value can be configured as follows.

[0208] The discovery message for relay UE2 may include the user information ID (annotifier ID) of relay UE2 and / or a specific value representing the hop count. This specific value may be a configuration / defined value corresponding to "unknown", the maximum available hop count value, or a preset value.

[0209] (2) Upon receiving the discovery message sent in step (1), relay UE1 and / or relay UE3 may trigger the transmission of the discovery message. In this case, relay UE1 and / or relay UE3 may send a discovery message including the following information.

[0210] 1) Discovery message for relay UE1

[0211] ① User information ID (annotifier ID) of relay UE1, ② User information ID (neighbor ID) of relay UE2, and ③ Hop count (=1)

[0212] For example, when a specific value corresponding to "unknown" is included / configured in the discovery message of relay UE2, relay UE1 can configure a hop count of '1' for its discovery message. For example, when a specific value corresponding to "unknown" is configured / included in the discovery message of relay UE2, relay UE1 can configure a hop count value based on the signal strength of the Uu link, whether relay UE1 is directly connected to the gNB, etc., as the hop count value of the discovery message, instead of configuring its own hop count by incrementing the specific value by 1.

[0213] 2) Discovery message for relay UE3

[0214] ① User information ID (annotifier ID) of relay UE3, ② User information ID (neighbor ID) of relay UE2, and ③ Hop count (=unknown or a specific value corresponding to unknown).

[0215] For example, when relay UE3 is a relay UE that cannot directly connect to the gNB, relay UE3 may also be unaware of its own hop count associated with multi-hop U2N relays. Accordingly, relay UE3 may send a discovery message in which a specific value corresponding to "unknown" is configured / included.

[0216] (3) When the relay UE2 receives a discovery message from the relay UE1 and / or the relay UE3 (for example, when a discovery message triggered by the reception of the discovery message of the relay UE2 is received), the relay UE2 may trigger the transmission of a discovery message configured as follows.

[0217] ① User information ID (annotifier ID) of relay UE2

[0218] ② User information ID (neighbor ID) of relay UE1.

[0219] - The ID of relay UE3 is excluded from the neighbor IDs in the discovery message. This is because the hop count value configured / included in the discovery message of relay UE3 corresponds to "unknown", preventing relay UE2 from accurately identifying the number of hops required to connect to the gNB via relay UE3.

[0220] ③ Jump count = 2

[0221] - For example, the hop count value included in the discovery message sent by relay UE2 can be indicated / configured to be obtained by incrementing the minimum hop count value among the received discovery messages by 1. Alternatively, when receiving discovery messages from multiple relay UEs 1' (e.g., relay UEs capable of directly connecting to the gNB) with the same hop count value, relay UE2 may include a neighbor list containing all user information IDs of the multiple relay UEs in its discovery message. Alternatively, when receiving discovery messages from multiple relay UEs 2' (e.g., relay UEs not capable of directly connecting to the gNB), relay UE2 may exclude the user information IDs of the multiple relay UEs from the neighbor list. Similar to relay UE1, relay UE1' may refer to a UE capable of directly connecting to the gNB (e.g., a relay UE capable of reaching the gNB in ​​one hop), and similar to relay UE2, relay UE2' may refer to a UE capable of indirectly connecting to the gNB through another relay UE1 (or relay UE1') (e.g., a relay UE capable of reaching the gNB in ​​two or more hops).

[0222] (4) For relay UE1 and / or relay UE3 that have received a discovery message sent by relay UE2 (e.g., the discovery message sent in step '(3)'), the transmission of the discovery message may be triggered. Alternatively, the transmission of discovery messages from relay UE1 and / or relay UE3 may be performed periodically at regular time intervals. For example, when relay UE1 and / or relay UE3 have sent a discovery message in step '(2)', if a specific timer has not yet expired (or a specific time has not yet passed), relay UE1 and / or relay UE3 may not trigger the transmission of the discovery message (which would otherwise be prompted by the reception of the discovery message from relay UE2 in step '(3)').

[0223] When a discovery message is triggered in relay UE1 and / or relay UE3, the triggered discovery message may include the following information.

[0224] 1) Discovery message for relay UE3

[0225] ① User information ID (annotifier ID) of relay UE3.

[0226] ② User information ID (neighbor ID) of relay UE2.

[0227] ③ Jump count = 3

[0228] 2) Discovery message for relay UE1

[0229] ① User information ID (annotifier ID) of relay UE1.

[0230] ② User information ID (neighbor ID) of relay UE2.

[0231] ③ Jump count = 1

[0232] As described above, even if relay UE2 and relay UE3 do not know their initial hop count associated with multi-hop U2N relay communication and which relay UEs they can reach the gNB, they can still identify the hop count and which relay UEs the gNB can reach based on the steps ((1) to (4)) described above.

[0233] When a discovery message is triggered (due to receiving a discovery message from another relay UE), relay UE1 (or Uu-SL relay UE) and / or relay UE2 (or SL-SL relay UE) may simultaneously trigger a connection establishment procedure with the gNB (e.g., RRCSetup, RRCReestablishment, or RRCSetup). For example, in multi-hop U2N relay operations, RRC connection establishment via multiple hops needs to be performed sequentially after the discovery operation. In this case, a considerable delay may occur when performing initial setup for a remote UE. To minimize this delay, the relay UE (e.g., a relay UE performing multi-hop relay communication) may need to trigger the (RRC) connection establishment to the gNB simultaneously with the triggering of the discovery message transmission. For this purpose, when the discovery message is sent from the higher layer to the AS layer, the connection establishment to the gNB can be indicated simultaneously. Alternatively, when a message is sent in the AS layer via SL-SRB4 (signaling bearer for discovery message transmission), the relay UE (a multi-hop capable relay UE) can be configured to trigger RRC connection establishment.

[0234] Alternatively, when performing the discovery process based on discovery model B, the relay UE may send a response message to a solicitation message received from a remote UE (or another relay UE). Even in this case, the relay UE may trigger the aforementioned RRC connection establishment process.

[0235] The above operation can be triggered by sending / receiving discovery messages (e.g., discovery announcements, discovery requests, or discovery responses), which is separate from (or different from) the operation triggered in conventional Rel-17 U2N trunks when a trunk UE in the RRC_IDLE / INACTIVE state receives an RRCSetupRequest (or RRCReestablishmentRequest, or RRCResume) message via a designated SRB0 / 1. This may have the advantage of faster RRC connection establishment compared to conventional Rel-17 U2N trunk UE operations. However, from the perspective of a trunk UE that is ultimately not selected as a trunk UE, this may be an unnecessary operation, as RRC connection establishment should also be performed on trunk UEs that have not yet been selected as trunk UEs. Therefore, the above operation can only be performed when multi-hop trunk operations are triggered due to urgent reasons. For example, the RRC connection establishment procedure can be triggered only for the relay UE and / or remote UE that sends a discovery message including emergency-related indication information (or indicator), or for the relay UE that triggers the transmission / forwarding of the discovery message by receiving the discovery message, according to the above operations. This is because, when multi-hop relay operations are required for emergency-related operations, it may be necessary to perform initial access with minimal latency, even if unnecessary RRC connection operations are performed for some relay UEs.

[0236] Alternatively, the transition of a relay UE from the IDLE / INACTIVE state to the CONNECTED state can be triggered via a PC5-RRC message. For example, a remote UE (and / or an intermediate relay UE) can select a relay UE through a discovery procedure and establish a PC5-RRC connection with the selected relay UE. During the establishment of the PC5-RRC connection, the remote UE (and / or the intermediate relay UE) can send an indication (or indicator) to the single relay UE to trigger the transition to the RRC_CONNECTED state. For example, the indication (or indicator) can be information included in an RRCReconfigurationSidelink message, or it can be conveyed via an RRCReconfigurationSidelink message. Alternatively, the indication can be conveyed via a specific value in a separate PC5-RRC message. Upon receiving the indication (or indicator), the relay UE can perform operations for transitioning to the RRC_CONNECTED state while in the RRC_IDLE / INACTIVE state. Additionally, when a relay UE receives an indication / indicator (via PC5-RRC message) that triggers a transition to the RRC_CONNECTED state from a remote UE or another relay UE, the relay UE may also send an indication (or indicator) that triggers a transition to the RRC_CONNECTED state to the relay UE that it previously hopped to (e.g., the relay UE in the direction closer to the gNB).

[0237] Alternatively, when a relay UE (e.g., relay UE1) receives an indication (or indicator) from a remote UE or another relay UE (e.g., relay UE2) to trigger a transition from the RRC_IDLE / INACTIVE state to the RRC_CONNECTED state, the relay UE (e.g., relay UE1) may currently be in the RRC_IDLE / INACTIVE state (or may be located in a suitable cell or in a camped state). In this case, the relay UE (e.g., relay UE1) may trigger an RRC connection establishment procedure with the gNB when the signal strength against the gNB is greater than or equal to a (pre-)set specific threshold. Alternatively, if the relay UE receives an indication (or indicator) for transitioning to the RRC connected state, but the signal strength against the gNB is less than or equal to a preset specific threshold, the relay UE may determine that it is difficult to operate as a relay UE for connecting to the gNB. In this scenario, the relay UE can establish an SL connection with another suitable relay UE, or it can trigger a discovery (or relay selection) procedure to discover another suitable relay UE (e.g., a relay UE capable of directly connecting to the gNB). In this case, the relay UE can forward / send an indication (or indicator) for transitioning to the RRC_CONNECTED state to the relay UE selected through the aforementioned procedure.

[0238] Alternatively, a remote UE performing MH relay operation can establish an end-to-end (e2e) SL connection with a relay UE (or relay UE1) directly connected to the gNB, similar to U2U operation in Rel-18 relay. In this case, the remote UE intending to establish a U2N connection with the gNB can send a message indicating a transition to the RRCCONNECTED state to the relay UE directly connected to the gNB via a PC5-RRC message. For example, when the remote UE sends an RRCSetupRequest message to the gNB via a relay UE (or relay UE2) directly connected to the remote UE via a side link (SL), the remote UE can send the RRCSetupRequest message through the designated SL_RLC channel and simultaneously send a separate PC5-RRC message (e.g., including a PC5 message indicating an indication to trigger a transition to the RRC CONNECTED state) to the relay UE directly connected to or capable of directly connecting to the gNB. In such an operation, when relay UE2 performs preparation operations for transitioning to the RRC CONNECTED state, relay UE1 (the relay UE instructed by the remote UE to transition to the RRC CONNECTED state) can also perform preparation operations for transitioning to the RRC CONNECTED state. In this case, the latency of establishing an RRC connection with the gNB via multi-hop U2N relay can be significantly reduced.

[0239] To prevent a remote UE (or relay UE) from unnecessarily instructing a relay UE already in the RRC_CONNECTED state to transition to the RRC_CONNECTED state, the remote UE can be provided with information related to the relay UE's RRC state during the establishment of an SL connection with the relay UE. For example, when establishing an SL connection between a remote UE (or relay UE2) and a relay UE (or relay UE1), information about the relay UE's (or relay UE1's) RRC state can be provided to the remote UE (or relay UE2) via an RRCReconfigurationSidelink message or an RRCReconfigurationCompleteSidelink message.

[0240] If a relay UE is in the RRC_CONNECTED state (or when it enters the RRC_CONNECTED state), the relay UE can notify the remote UE that it has transitioned to the RRC_CONNECTED state. Upon receiving this notification, the remote UE (or intermediate relay UE) may not send a request / suggestion to the relay UE to trigger an indication (or indicator) for transitioning to the RRC_CONNECTED state.

[0241] As stated above, even for discovery model A, the proposed disclosures can effectively support MH relay operations.

[0242] The proposed method can be natively applied to the operation of devices / sensors performing Internet of Things (IoT) or machine-to-machine (M2M) communication connecting to a network or another device via other sensors / devices. In this case, the remote UE can be a device / sensor attempting to connect to the network (or another sensor / device) via another sensor / device, and the relay UE can be a sensor / device relaying a connection to another sensor / device or network. For example, multiple IoT sensors / devices can perform multi-hop relay communication by executing the proposed discovery process based on multi-hop discovery model A.

[0243] Figure 15 This is a diagram illustrating the method by which a discovery message is sent by a first relay UE.

[0244] The first relay UE can forward / relay data between the remote UE and the BS via multi-hop U2N relay communication. The first relay UE can be an intermediate relay UE (or relay UE2) that cannot be directly connected to the BS or gNB. When receiving a discovery message from another relay UE based on the discovery model A described above, the first relay UE can send / broadcast a discovery message for forwarding the received discovery message. Alternatively, when the first relay UE is connected to a relay UE SL that is directly connected to the BS, the first relay UE can forward only the discovery messages received from the corresponding relay UE.

[0245] Specifically, based on the fact that the hop count associated with the multi-hop UE-to-network (U2N) relay is not specified, the first relay UE may send / broadcast a first discovery message (S151). For example, regarding multi-hop U2N relay operation, the first relay UE may not be able to directly connect to the gNB or BS, and may fail to receive a discovery message from another relay UE (or the signal strength for the gNB or BS is less than a preset threshold, and only a discovery message without an appropriate hop count is received). In this case, the first relay UE, as an intermediate relay UE, may not be able to specify its own hop count for connecting to the gNB or BS due to the characteristics of the multi-hop structure. For example, when the signal strength between the first relay UE and the BS is less than a preset threshold (e.g., when a signal strength that makes direct connection to the BS difficult is measured), the first relay UE may have difficulty specifying / determining its own hop count until it receives a discovery message with an appropriate hop count from another relay UE. In this case, even if a discovery message is not received from another relay UE, the first relay UE may trigger the transmission of its discovery message for the purpose of specifying / identifying the hop count. For example, when a first relay UE cannot directly connect to the BS and therefore finds it difficult to specify a hop count, a discovery message can be triggered to determine / specify the value of the hop count associated with a multi-hop U2N relay. The first discovery message may include the first relay UE's user information (or user information ID) and a hop count set to indicate that the hop count has not been specified. For example, a specific value corresponding to "unknown" hop count can be preset / defined, and the first relay UE can send a first discovery message in which the hop count is set to that specific value. Another relay UE receiving the first discovery message can identify, based on that specific value, that the received discovery message was sent for the purpose of specifying the first relay UE's hop count.

[0246] Alternatively, the first discovery message may also include indications that U2N relay operations are based on multi-hops.

[0247] Subsequently, the first relay UE can receive a second discovery message (S153). For example, the first relay UE can receive a second discovery message including the user information ID of the first relay UE from another relay UE that has already received the first discovery message. For example, the second relay UE can broadcast a second discovery message based on the reception of the first discovery message to determine / specify the hop count of the first relay UE. For example, when the second relay UE is a relay UE that can directly connect to the BS (e.g., a relay UE whose signal strength to the BS is greater than or equal to a preset threshold, or relay UE1, or the last relay UE), the second relay UE can send a second discovery message including a hop count set to '1', its own user information ID (as an announcer ID), and the user information ID of the first relay UE (as a neighbor ID).

[0248] Subsequently, upon receiving a second discovery message that includes information about the first relay UE, the first relay UE can specify / determine its own hop count associated with the multi-hop U2N relay based on the second discovery message (S155). For example, when hop count 1 is configured in the second discovery message that includes its own user information, the first relay UE can determine / specify its own hop count as 2.

[0249] The first relay UE can then send a third discovery message (S157) which includes the determined hop count (i.e., the first hop count). The third discovery message is a message triggered by receiving the second discovery message, and can be a message generated based on the second discovery message or a message used to forward the second discovery message. The third discovery message may include the first hop count, the user information ID of the first relay UE, and the user information ID of the second relay UE that sent the second discovery message (e.g., as neighbor user information).

[0250] Alternatively, at the same time as triggering the transmission of the third discovery message, the first relay UE may simultaneously trigger the RRC connection establishment procedure with the BS via the second relay UE. For example, along with the transmission of the third discovery message, the first relay UE may perform the RRC connection establishment procedure with the BS via the second relay UE.

[0251] Figure 16 This is a diagram illustrating the method by which a second relay UE receives a discovery message.

[0252] The second relay UE can forward / relay data between the remote UE and the BS via multi-hop U2N relay communication. The second relay UE can be a relay UE (or relay UE1) capable of directly connecting to the BS or gNB. For example, the second relay UE can be a relay UE whose signal strength to the BS or gNB is greater than or equal to a preset threshold. In this case, the second relay UE can configure / specify its own hop count to 0 or 1. The first relay UE can send or receive its discovery messages based on discovery model A.

[0253] Specifically, the second relay UE can receive a first discovery message associated with multi-hop U2N relay (S161). As described above, the transmission of the first discovery message can be triggered based on the fact that the hop count has not been specified by the first relay UE. In this case, the first discovery message may include user information of the first relay UE and a hop count set to a specific value indicating that the hop count has not been specified. For example, the first discovery message may include a hop count with a pre-mapped / pre-configured specific value corresponding to an unknown value. The second relay UE can identify / identify based on this specific value that the first discovery message is a message triggered to determine / configure the hop count of the first relay UE. Alternatively, the first discovery message may also include indication information indicating that U2N relay operation is based on multi-hop.

[0254] The second relay UE can then send / broadcast a second discovery message (S163). For example, when the second relay UE receives the first discovery message, the sending of the second discovery message can be triggered based on the receipt of the first discovery message. The second relay UE can send / broadcast a second discovery message including the user information ID of the first relay UE, its own user information ID, and information about its own hop count. For example, when the second relay UE determines that the first discovery message was triggered for the purpose of specifying a hop count, the second relay UE can send a second discovery message in which its own hop count is configured / included, instead of the hop count obtained by incrementing the hop count of the first discovery message by 1. Alternatively, as described above, the second discovery message may include indication information indicating a transition to an RRC connection state and / or indication information indicating that U2N relay operation is based on multiple hops.

[0255] As described above, the proposed disclosure can effectively provide intermediate relay UEs that cannot specify hop counts due to the multi-hop structure in U2N relay communication with the opportunity to specify hop counts. Alternatively, the proposed disclosure can effectively provide the opportunity to identify paths for connecting to the gNB during the discovery process for multi-hop U2N relay communication. Alternatively, the proposed disclosure can minimize the latency caused by the establishment of multiple hops in multi-hop U2N relays by triggering the RRC state transition process simultaneously with the transmission of the discovery message. Alternatively, the proposed disclosure can prevent remote UEs that do not support multi-hop U2N relay operation from selecting the wrong relay UE during the discovery process by notifying the U2N relay operation of multi-hop support via the discovery message.

[0256] Example of a communication system using this disclosure

[0257] Although not limited thereto, the various descriptions, functions, processes, proposals, methods and / or operation flowcharts disclosed in this document can be applied to various fields requiring wireless communication / connectivity (5G) between devices.

[0258] In the following description, it will be illustrated in more detail with reference to the accompanying drawings. In the following drawings / description, unless otherwise specified, the same reference numerals may refer to the same or corresponding hardware blocks, software blocks or functional blocks.

[0259] Figure 17 An example of a communication system applied to this disclosure is shown.

[0260] Reference Figure 17 The communication system 1 applied to this disclosure includes wireless devices, base stations (BS), and networks. Herein, a wireless device refers to a device that performs communication using a radio access technology (RAT) (e.g., 5G New RAT (NR) or Long Term Evolution (LTE)) and may be referred to as a communication / radio / 5G device. Wireless devices may include (but are not limited to) robots 100a, vehicles 100b-1 and 100b-2, extended reality (XR) devices 100c, handheld devices 100d, home appliances 100e, Internet of Things (IoT) devices 100f, and artificial intelligence (AI) devices / servers 400. For example, a vehicle may include a vehicle with wireless communication capabilities, an autonomous vehicle, and a vehicle capable of performing communication between vehicles. Herein, a vehicle may include an unmanned aerial vehicle (UAV) (e.g., a drone). XR devices can include augmented reality (AR) / virtual reality (VR) / mixed reality (MR) devices, and can be implemented in the form of head-mounted displays (HMDs), head-up displays (HUDs) installed in vehicles, televisions, smartphones, computers, wearable devices, home appliances, digital signage, vehicles, robots, etc. Handheld devices can include smartphones, smart tablets, wearable devices (e.g., smartwatches or smart glasses) and computers (e.g., laptops). Home appliances can include TVs, refrigerators, and washing machines. IoT devices can include sensors and smart meters. For example, the BS and network can be implemented as wireless devices, and a particular wireless device 200a can operate as a BS / network node relative to other wireless devices.

[0261] Wireless devices 100a to 100f can connect to network 300 via BS 200. AI technology can be applied to wireless devices 100a to 100f, and wireless devices 100a to 100f can connect to AI server 400 via network 300. Network 300 can be configured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g., NR) network. Although wireless devices 100a to 100f can communicate with each other via BS 200 / network 300, wireless devices 100a to 100f can also perform direct communication (e.g., sidelink communication) without going through the BS / network. For example, vehicles 100b-1 and 100b-2 can perform direct communication (e.g., vehicle-to-vehicle (V2V) / vehicle-to-everything (V2X) communication). IoT devices (e.g., sensors) can perform direct communication with other IoT devices (e.g., sensors) or other wireless devices 100a to 100f.

[0262] Wireless communication / connections 150a, 150b, or 150c can be established between wireless devices 100a to 100f / BS 200 or between BS 200 and BS 200. In this document, wireless communication / connections can be established via various RATs (e.g., 5G NR) such as uplink / downlink communication 150a, sidelink communication 150b (or D2D communication), or inter-BS communication (e.g., relay, integrated access backhaul (IAB)). Wireless devices and BS / wireless devices can transmit / receive radio signals to / from each other via wireless communication / connections 150a and 150b. For example, wireless communication / connections 150a and 150b can transmit / receive signals via various physical channels. For this purpose, at least a portion of the configuration information for configuring the process of transmitting / receiving radio signals, various signal processing processes (e.g., channel coding / decoding, modulation / demodulation, and resource mapping / demapping), and resource allocation processes can be performed based on various proposals of this disclosure.

[0263] Examples of wireless devices using this disclosure

[0264] Figure 18 Examples of wireless devices applicable to this disclosure are shown.

[0265] Reference Figure 18 The first wireless device 100 and the second wireless device 200 can transmit radio signals via various RATs (e.g., LTE and NR). In this document, {first wireless device 100 and second wireless device 200} can correspond to... Figure 17 {Wireless Device 100x and BS 200} and / or {Wireless Device 100x and Wireless Device 100x}.

[0266] The first wireless device 100 may include one or more processors 102 and one or more memories 104, and additionally include one or more transceivers 106 and / or one or more antennas 108. The processors 102 may control the memories 104 and / or the transceivers 106, and may be configured to implement the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed herein. For example, the processor 102 may process information in the memory 104 to generate a first information / signal, and then transmit a radio signal including the first information / signal via the transceivers 106. The processor 102 may receive a radio signal including a second information / signal via the transceivers 106, and then store the information obtained by processing the second information / signal in the memory 104. The memory 104 may be connected to the processor 102 and may store various information relating to the operation of the processor 102. For example, the memory 104 may store software code including commands for performing some or all of the processes controlled by the processor 102 or for performing the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed herein. In this document, processor 102 and memory 104 may be part of a communication modem / circuit / chip designed to implement RAT (e.g., LTE or NR). Transceiver 106 may be connected to processor 102 and transmit and / or receive radio signals via one or more antennas 108. Each transceiver 106 may include a transmitter and / or a receiver. Transceiver 106 may be used interchangeably with radio frequency (RF) units. In this disclosure, a wireless device may refer to a communication modem / circuit / chip.

[0267] Specifically, the first wireless device or first relay UE 100 may include a processor 102 connected to the transceiver 106, and a memory 104. The memory 104 may include at least one program for executing combined... Figures 13 to 16 The operations related to the described implementation methods.

[0268] The processor 102 can control the transceiver 106 to send a first discovery message based on the fact that the hop count associated with the multi-hop U2N relay has not been specified, control the transceiver 106 to receive a second discovery message, and determine a first hop count associated with the first relay UE based on the second discovery message including information about the first relay UE.

[0269] Alternatively, a processing device including the processor 102 and the memory 104 may be configured. In this case, the processing device may include: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause a first relay UE to send a first discovery message based on the fact that a hop count associated with a multi-hop U2N relay has not been specified, receive a second discovery message, and determine a first hop count associated with the first relay UE based on information about the first relay UE included in the second discovery message.

[0270] The second wireless device 200 may include one or more processors 202 and one or more memories 204, and additionally include one or more transceivers 206 and / or one or more antennas 208. The processors 202 may control the memories 204 and / or the transceivers 206, and may be configured to implement the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document. For example, the processors 202 may process information in the memories 204 to generate a third information / signal, and then transmit a radio signal including the third information / signal via the transceivers 206. The processors 202 may receive a radio signal including a fourth information / signal via the transceivers 206, and then store the information obtained by processing the fourth information / signal in the memories 204. The memories 204 may be connected to the processors 202 and may store various information relating to the operation of the processors 202. For example, the memories 204 may store software code including commands for performing some or all of the processes controlled by the processors 202 or for performing the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document. In this document, processor 202 and memory 204 may be part of a communication modem / circuit / chip designed to implement RAT (e.g., LTE or NR). Transceiver 206 may be connected to processor 202 and transmit and / or receive radio signals via one or more antennas 208. Each transceiver 206 may include a transmitter and / or a receiver. Transceiver 206 may be used interchangeably with an RF unit. In this disclosure, a wireless device may represent a communication modem / circuit / chip.

[0271] Specifically, the second wireless device or second relay UE 200 may include a processor 202 connected to the transceiver 206, and a memory 204. The memory 204 may include at least one program for executing combined... Figures 13 to 16 The operations related to the described implementation methods.

[0272] The processor 202 can control the transceiver 206 to receive a first discovery message, and control the transceiver 206 to send a second discovery message based on the receipt of the first discovery message. The first discovery message may include a hop count set to indicate that the hop count associated with the multi-hop U2N relay has not been specified as a first value.

[0273] The hardware elements of wireless devices 100 and 200 will be described in more detail below. One or more protocol layers may be implemented by (but are not limited to) one or more processors 102 and 202. For example, one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, and SDAP). One or more processors 102 and 202 may generate one or more Protocol Data Units (PDUs) and / or one or more Service Data Units (SDUs) according to the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document. One or more processors 102 and 202 may generate messages, control information, data, or information according to the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document. One or more processors 102 and 202 may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information, according to the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document, and provide the generated signals to one or more transceivers 106 and 206. One or more processors 102 and 202 may receive signals (e.g., baseband signals) and acquire PDUs, SDUs, messages, control information, data, or information from one or more transceivers 106 and 206, according to the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document.

[0274] One or more processors 102 and 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. One or more processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof. As an example, one or more application-specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field-programmable gate arrays (FPGAs) may be included in one or more processors 102 and 202. The descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document may be implemented using firmware or software, and the firmware or software may be configured to include modules, processes, or functions. Firmware or software configured to execute the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document may be included in one or more processors 102 and 202 or stored in one or more memories 104 and 204 to be driven by one or more processors 102 and 202. The descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document can be implemented using firmware or software in the form of code, commands, and / or command sets.

[0275] One or more memories 104 and 204 may be connected to one or more processors 102 and 202 and store various types of data, signals, messages, information, programs, code, instructions, and / or commands. One or more memories 104 and 204 may be configured with read-only memory (ROM), random access memory (RAM), electrically erasable programmable read-only memory (EPROM), flash memory, hard disk drive, registers, cache memory, computer-readable storage media, and / or combinations thereof. One or more memories 104 and 204 may be located internally and / or externally to one or more processors 102 and 202. One or more memories 104 and 204 may be connected to one or more processors 102 and 202 via various technologies such as wired or wireless connections.

[0276] One or more transceivers 106 and 206 may transmit user data, control information, and / or radio signals / channels mentioned in the methods and / or operation flowcharts of this document to one or more other devices. One or more transceivers 106 and 206 may receive user data, control information, and / or radio signals / channels mentioned in the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document from one or more other devices. For example, one or more transceivers 106 and 206 may be connected to one or more processors 102 and 202 and transmit and receive radio signals. For example, one or more processors 102 and 202 may perform controls to enable one or more transceivers 106 and 206 to transmit user data, control information, or radio signals to one or more other devices. One or more processors 102 and 202 may perform controls to enable one or more transceivers 106 and 206 to receive user data, control information, or radio signals from one or more other devices. One or more transceivers 106 and 206 may be connected to one or more antennas 108 and 208, and one or more transceivers 106 and 206 may be configured to transmit and receive user data, control information, and / or radio signals / channels mentioned in the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this document through one or more antennas 108 and 208. In this document, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106 and 206 may convert received radio signals / channels, etc., from RF band signals to baseband signals so that the received user data, control information, radio signals / channels, etc., may be processed using one or more processors 102 and 202. One or more transceivers 106 and 206 may convert user data, control information, radio signals / channels, etc., processed using one or more processors 102 and 202 from baseband signals to RF band signals. For this purpose, one or more transceivers 106 and 206 may include (analog) oscillators and / or filters.

[0277] Examples of wireless devices using this disclosure

[0278] Figure 19 Another example of a wireless device applied to this disclosure is shown. The wireless device can be implemented in various forms depending on the use case / service (see reference). Figure 17 ).

[0279] Reference Figure 19 Wireless devices 100 and 200 can correspond to Figure 18 The wireless devices 100 and 200 can be configured from various elements, components, units / parts, and / or modules. For example, each of the wireless devices 100 and 200 may include a communication unit 110, a control unit 120, a memory unit 130, and an additional component 140. The communication unit may include a communication circuit 112 and a transceiver 114. For example, the communication circuit 112 may include... Figure 18 One or more processors 102 and 202 and / or one or more memories 104 and 204. For example, transceiver 114 may include Figure 18 The device comprises one or more transceivers 106 and 206 and / or one or more antennas 108 and 208. Control unit 120 is electrically connected to communication unit 110, memory 130, and add-on components 140, and controls the overall operation of the wireless device. For example, control unit 120 may control the electrical / mechanical operation of the wireless device based on programs / code / commands / information stored in memory unit 130. Control unit 120 may transmit information stored in memory unit 130 to an external source (e.g., other communication devices) via communication unit 110 through a wireless / wired interface, or store information received from an external source (e.g., other communication devices) via communication unit 110 in memory unit 130 via a wireless / wired interface.

[0280] The additional component 140 can be configured differently depending on the type of wireless device. For example, the additional component 140 may include at least one of a power supply unit / battery, an input / output (I / O) unit, a drive unit, and a computing unit. The wireless device can be configured according to (but is not limited to) a robot ( Figure 17 100a), vehicles ( Figure 17 100b-1 and 100b-2), XR device ( Figure 17 100c), handheld device ( Figure 17 100d), home appliances ( Figure 17 100e), IoT devices ( Figure 17 100f), digital broadcasting terminals, holographic devices, public safety devices, MTC devices, medical devices, fintech devices (or financial devices), security devices, climate / environment devices, AI servers / devices ( Figure 17 400), BS ( Figure 17 This can be achieved through 200 network nodes, etc. Wireless devices can be used in mobile or fixed locations depending on the use case / service.

[0281] exist Figure 19 In wireless devices 100 and 200, all elements, components, units / parts, and / or modules may be interconnected via wired interfaces, or at least a portion thereof may be wirelessly connected via communication unit 110. For example, in each of wireless devices 100 and 200, control unit 120 and communication unit 110 may be wired connected, and control unit 120 and first units (e.g., 130 and 140) may be wirelessly connected via communication unit 110. The various elements, components, units / parts, and / or modules within wireless devices 100 and 200 may also include one or more elements. For example, control unit 120 may be configured as a collection of one or more processors. As an example, control unit 120 may be configured as a collection of communication control processors, application processors, electronic control units (ECUs), graphics processing units, and memory control processors. In another example, memory 130 may be configured as random access memory (RAM), dynamic RAM (DRAM), read-only memory (ROM), flash memory, volatile memory, non-volatile memory, and / or combinations thereof.

[0282] Examples of vehicles or autonomous vehicles using this disclosure

[0283] Figure 20 The illustration shows a vehicle or autonomous vehicle applicable to this disclosure. The vehicle or autonomous vehicle may be a mobile robot, car, train, manned / unmanned aerial vehicle (AV), vessel, etc.

[0284] Reference Figure 20 The vehicle or autonomous vehicle 100 may include an antenna unit 108, a communication unit 110, a control unit 120, a drive unit 140a, a power supply unit 140b, a sensor unit 140c, and an autonomous driving unit 140d. The antenna unit 108 may be configured as part of the communication unit 110. Blocks 110 / 130 / 140a to 140d respectively correspond to... Figure 19 Blocks 110 / 130 / 140.

[0285] Communication unit 110 can send and receive signals (e.g., data and control signals) to and from external devices such as other vehicles, BSs (e.g., gNBs and roadside units), and servers. Control unit 120 can perform various operations by controlling the components of the vehicle or autonomous vehicle 100. Control unit 120 may include electronic control unit (ECU). Additionally, drive unit 140a enables the vehicle or autonomous vehicle 100 to move on a road. Drive unit 140a may include an engine, motor, powertrain, wheels, brakes, steering mechanism, etc. Power supply unit 140b supplies power to the vehicle or autonomous vehicle 100 and includes wired / wireless charging circuitry, battery, etc. Sensor unit 140c can acquire vehicle status, surrounding environment information, user information, etc. Sensor unit 140c may include inertial measurement unit (IMU) sensors, collision sensors, wheel sensors, speed sensors, slope sensors, weight sensors, heading sensors, position modules, vehicle forward / reverse sensors, battery sensors, fuel sensors, tire sensors, steering sensors, temperature sensors, humidity sensors, ultrasonic sensors, lighting sensors, pedal position sensors, etc. Autonomous driving unit 140d can implement technologies for maintaining the vehicle within its lane, technologies for automatically adjusting speed (e.g., adaptive cruise control), technologies for autonomously driving along a determined path, and technologies for automatically setting a route if a destination is set, etc.

[0286] For example, communication unit 110 can receive map data, traffic information data, etc., from an external server. Autonomous driving unit 140d can generate an autonomous driving path and driving plan from the acquired data. Control unit 120 can control drive unit 140a, enabling the vehicle or autonomous vehicle 100 to move along the autonomous driving path according to the driving plan (e.g., speed / direction control). During autonomous driving, communication unit 110 can periodically or non-periodically acquire recent traffic information data from an external server and acquire surrounding traffic information data from neighboring vehicles. During autonomous driving, sensor unit 140c can acquire vehicle status and / or surrounding environment information. Autonomous driving unit 140d can update the autonomous driving path and driving plan based on newly acquired data / information. Communication unit 110 can transmit information about vehicle location, autonomous driving path, and / or driving plan to an external server. The external server can predict traffic information data using AI technology, etc., based on information collected from the vehicle or autonomous vehicle, and provide the predicted traffic information data to the vehicle or autonomous vehicle.

[0287] Here, the wireless communication technologies implemented in the wireless devices (XXX, YYY) of this specification may include, in addition to narrowband IoT for low-power communication, LTE, NR, and 6G. For example, NB-IoT technology may be an example of low-power wide-area network (LPWAN) technology and may be implemented according to standards such as LTE Cat NB1 and / or LTE Cat NB2, and is not limited to the aforementioned names. Alternatively, the wireless communication technologies implemented in the wireless devices (XXX, YYY) of this specification may perform communication based on LTE-M technology. In this case, as an example, LTE-M technology may be an example of LPWAN technology and may be referred to by various names such as eMTC (enhanced machine-type communication). For example, LTE-M technology may be implemented according to at least one of various standards such as 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-BL (non-bandwidth limited), 5) LTE-MTC, 6) LTE machine-type communication, and / or 7) LTE M, and is not limited to the aforementioned names. Alternatively, considering low-power communication, the wireless communication technology implemented in the wireless devices (XXX, YYY) of this specification is at least one of ZigBee, Bluetooth, and Low Power Wide Area Network (LPWAN), and is not limited to the aforementioned names. As an example, ZigBee technology can be used to generate personal area networks (PANs) related to low / low power digital communication based on various standards such as IEEE 802.15.4, and can be referred to by various names.

[0288] The above-described embodiments represent combinations of components and features of this disclosure in a predetermined manner. Unless otherwise expressly stated, each component or feature should be considered optional. Each component or feature can be implemented without combination with other components or features. Some components and / or features can also be combined to constitute embodiments of this disclosure. The order of operations described in the embodiments of this disclosure can be changed. Certain configurations or features of one embodiment can be included in another embodiment, or replaced with corresponding configurations or features of another embodiment. Clearly, multiple claims not explicitly related by reference in the claims can be combined to constitute an embodiment, or can be included in new claims through post-application amendments.

[0289] This document primarily focuses on describing the signal transmission and reception relationship between the UE and the BS. This transmission and reception relationship can be extended similarly or identically to the signal transmission and reception between the UE and a relay, or between the BS and a relay. Specific operations described herein as being performed by the BS may, in some cases, be performed by upper-layer nodes. That is, in a network consisting of multiple network nodes, including the BS, various operations performed to achieve communication with the UE can be performed by the BS or by other network nodes different from the BS. The term "base station" can be replaced by terms such as fixed station, node B, eNodeB (eNB), or access point. Similarly, the term "terminal" can be replaced by terms such as user equipment (UE), mobile station (MS), or mobile subscriber station (MSS).

[0290] The embodiments of this disclosure can be implemented in various ways, such as hardware, firmware, software, or a combination thereof. In the case of hardware implementation, the embodiments of this disclosure can be implemented by one or more ASICs (Application-Specific Integrated Circuits), DSPs (Digital Signal Processors), DSPDs (Digital Signal Processing Devices), PLDs (Programmable Logic Devices), FPGAs (Field-Programmable Gate Arrays), processors, controllers, microcontrollers, or microprocessors.

[0291] In the case of firmware or software implementation, embodiments of this disclosure can be implemented in the form of modules, processes, functions, etc., that implement the above-described functions or operations. Software code can be stored in a memory unit and executed by a processor. The memory unit can be located inside or outside the processor and can exchange data with the processor through various known methods.

[0292] Those skilled in the art will understand that this disclosure may be implemented in other specific ways besides those described herein without departing from the spirit and essential features of this disclosure. Therefore, the above embodiments should be construed as exemplary and not restrictive in all respects. The scope of this disclosure should be determined by the appended claims and their legal equivalents, not by the foregoing description, and all changes falling within the meaning and equivalence of the appended claims are intended to be covered therewith.

[0293] Industrial applicability

[0294] The embodiments described above can be applied to various mobile communication systems.< / gnb>

Claims

1. A method performed by a first trunk user equipment (UE), the method comprising the following steps: A first discovery message is sent because the hop count associated with multi-hop UE to network U2N relay is not specified. Receive the second discovery message; as well as Based on the second discovery message including information about the first relay UE, a first hop count associated with the first relay UE is determined.

2. The method according to claim 1, wherein, Even if no discovery message is received from another relay UE, the transmission of the first discovery message is triggered to specify the hop count associated with the multi-hop U2N relay.

3. The method according to claim 1, wherein, The first discovery message includes user information of the first relay UE and a hop count set to indicate that the hop count has not been specified by a specific value.

4. The method according to claim 1, wherein, The first relay UE is an intermediate relay UE whose signal strength at the base station BS is less than a preset threshold.

5. The method according to claim 1, wherein, The first hop count is determined as a value obtained by incrementing the hop count value included in the second discovery message by 1.

6. The method according to claim 1, wherein, The first discovery message also includes indication information indicating that the U2N relay operation is based on multi-hop.

7. The method according to claim 1, further comprising the following steps: The receipt of the second discovery message triggers the sending of a third discovery message. The third discovery message includes the first hop count and the user information identifier of the second relay UE that sent the second discovery message.

8. The method according to claim 7, wherein, Based on the transmission of the third discovery message, the first relay UE triggers the Radio Resource Control (RRC) connection establishment process with the BS.

9. The method according to claim 1, wherein, The second discovery message is received from a second relay UE whose signal strength against the BS is greater than or equal to a preset threshold, and The second discovery message includes the user information identifier of the second relay UE and the user information identifier of the first relay UE.

10. A computer-readable recording medium that records a program for performing the method according to claim 1.

11. A first trunk user equipment (UE), the first trunk UE comprising: RF transceiver; as well as The processor is connected to the RF transceiver. The processor is configured to control the RF transceiver to send a first discovery message based on the fact that the hop count associated with the multi-hop UE to the network U2N relay is not specified, to control the RF transceiver to receive a second discovery message, and to determine a first hop count associated with the first relay UE based on the information about the first relay UE included in the second discovery message.

12. The first relay UE according to claim 11, wherein, Even if no discovery message is received from another relay UE, the transmission of the first discovery message is triggered to specify the hop count associated with the multi-hop U2N relay.

13. A processing apparatus for controlling a first relay user equipment (UE), the processing apparatus comprising: At least one processor; as well as At least one memory, connected to the at least one processor and storing instructions, which, when executed by the at least one processor, cause the first relay UE to: Since the hop count associated with the multi-hop UE to the network U2N relay is not specified, a first discovery message is sent, a second discovery message is received, and a first hop count associated with the first relay UE is determined based on the second discovery message including information about the first relay UE.

14. A method performed by a second trunk user equipment (UE), the method comprising the following steps: Receive the first discovery message; as well as Based on the receipt of the first discovery message, a second discovery message is sent. The first discovery message includes a hop count that is set to indicate that the hop count associated with the multi-hop UE to the network U2N relay has not been specified.

15. A second trunk user equipment (UE), the second trunk UE comprising: RF transceiver; as well as The processor is connected to the RF transceiver. The processor is configured to control the RF transceiver to receive a first discovery message, and to control the RF transceiver to send a second discovery message based on the receipt of the first discovery message. The first discovery message includes a hop count that is set to indicate that the hop count associated with the multi-hop UE to the network U2N relay has not been specified.

Images