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

Abstract

A method for forwarding a discovery message by a relay terminal in a wireless communication system according to various embodiments and an apparatus therefor are disclosed. Disclosed are a method and an apparatus therefor, the method comprising the steps of: receiving a first discovery message for a multi-hop relay; and determining whether to forward the first discovery message based on the first timestamp and the time budget included in the first message.

Description

Technical Field

[0001] This disclosure relates to a method and apparatus for forwarding discovery messages for multi-hop relay by a relay user equipment (UE) in a wireless communication system. Background Technology

[0002] Wireless communication systems are being widely deployed to provide various types of communication services such as voice and data. Typically, a wireless communication system is a multiple access system capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit 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) refers to a communication method that establishes a direct link between user equipment (UE) and allows UEs to exchange voice or data directly without going through a base station (BS). SL is considered a solution to alleviate the burden on base stations (BS) caused by the rapid growth of data services.

[0004] Vehicle-to-Everything (V2X) is a communication technology that allows vehicles to exchange information with other vehicles, pedestrians, and infrastructure 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 via PC5 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 are improved compared to traditional radio access technologies. Therefore, communication systems for services / UEs that are sensitive to reliability and latency are being discussed. Next-generation radio access technologies that incorporate enhanced mobile broadband communications, massive machine-type communications (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, vehicle-to-everything (V2X) communications can be supported.

[0006] Figure 1 This is a diagram comparing 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), Cooperation 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 about the vehicle (such as 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 100 ms. 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 range 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 maneuver 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, vehicles, logical entities, pedestrian UEs, and / or V2X application servers can exchange raw or processed data acquired through local sensors, or live video data. Thus, for example, a vehicle can identify an improved environment relative 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 the case of public transportation, cloud-based driving can be used to operate or control remote vehicles. For example, access to a cloud-based backend service platform can be considered for remote driving.

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

[0015] Technical issues

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

[0017] Those skilled in the art who are familiar with the embodiments should understand that the objectives that the embodiments can achieve are not limited to those specifically described above, and that the above and other objectives will become clearer through the following detailed description.

[0018] Technical solution

[0019] According to one aspect, a method for forwarding a discovery message by a relay user equipment (UE) in a wireless communication system may include: receiving a first discovery message for multi-hop relay; and determining whether to forward the first discovery message based on a first timestamp and time budget included in the first discovery message.

[0020] Alternatively, based on a remaining time budget greater than a specific threshold, a relay UE may forward a first discovery message, where the remaining time budget is the time budget minus the difference between the first timestamp and the second timestamp.

[0021] Alternatively, based on the remaining time budget being equal to or less than a specific threshold, the relay UE may not forward the first discovery message, where the remaining time budget is the time budget minus the difference between the first timestamp and the second timestamp.

[0022] Alternatively, the initial value of the time budget can be determined based on the Quality of Service (QoS) associated with the messages to be sent between the first and second devices via a multi-hop relay connection.

[0023] Alternatively, based on the cumulative time being less than a certain threshold, the relay UE may forward the first discovery message, where the cumulative time is the time budget plus the difference between the first timestamp and the second timestamp.

[0024] Alternatively, the relay UE may forward the first discovery message after replacing the first timestamp with the second timestamp and the time budget with the remaining time budget.

[0025] Alternatively, the first discovery message may also include a first sequence number.

[0026] Alternatively, the method may further include: after forwarding the first discovery message, receiving a second discovery message including a second sequence number; and not forwarding the second discovery message based on the fact that the source device and the target device are the same between the first discovery message and the second discovery message, and that the second sequence number is the same as the first sequence number.

[0027] Alternatively, the first discovery message may also include information about the first hop count.

[0028] Alternatively, the method may further include: after forwarding the first discovery message, receiving a second discovery message including a second hop count; and not forwarding the second discovery message based on the fact that the source device and the target device are the same between the first discovery message and the second discovery message, and the second hop count is greater than the first hop count.

[0029] Alternatively, multi-hop relay can be a user equipment-to-network (U2N) relay used to send and receive data between a remote UE and the network.

[0030] According to another aspect, a computer-readable recording medium may be provided on which a program for performing a multi-hop relay discovery message forwarding method is recorded.

[0031] According to another aspect, a relay UE for performing a multi-hop relay discovery message forwarding method can be provided.

[0032] According to another aspect, a processing apparatus for controlling a relay UE that performs a multi-hop relay discovery message forwarding method can be provided.

[0033] According to another aspect, a method for sending a discovery message by a first device in a wireless communication system may include: sending a discovery message for connecting to a second device via a multi-hop relay; and receiving a response message for the discovery message. The discovery message may include a first timestamp and a time budget, the value of which is determined based on the QoS associated with the message to be sent to the second device via the multi-hop relay.

[0034] According to another option, a first device for performing the discovery message sending method can be provided.

[0035] Beneficial effects

[0036] According to embodiments of this disclosure, relay communication can be performed more accurately and efficiently in a wireless communication system.

[0037] The effects that can be achieved by the implementation methods are not limited to those specifically described above, and those skilled in the art will gain a clearer understanding of other effects not mentioned herein through the following detailed description. Attached Figure Description

[0038] The accompanying drawings, which are included to provide a further understanding of this disclosure and are incorporated into and constitute a part of this application, illustrate embodiments of this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0039] Figure 1 This is a diagram used to explain the difference between RAT-based V2X communication prior to NR and NR-based V2X communication.

[0040] Figure 2 The structure of an LTE system with applicable implementation methods is illustrated.

[0041] Figure 3 The structure of an NR system according to an applicable implementation is illustrated.

[0042] Figure 4 The structure of an NR radio frame applicable to the implementation method is illustrated.

[0043] Figure 5 The time slot structure of an NR frame applicable to this implementation is illustrated.

[0044] 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.

[0045] Figure 7 An electromagnetic spectrum according to an embodiment of the present disclosure is illustrated.

[0046] Figure 8 An example of a radio protocol architecture for SL communication is given.

[0047] Figure 9 An example of a UE performing V2X or SL communication is shown.

[0048] Figure 10 Examples of resource units for V2X or SL communication are shown.

[0049] Figure 11 An example of a BWP based on an embodiment of this disclosure is shown.

[0050] Figure 12 This illustrates the process by which a UE performs V2X or SL communication based on the transmission mode.

[0051] Figure 13 This is a schematic diagram used to explain the control plane process of L2 U2N relay (UE to network relay).

[0052] Figure 14 This is a schematic diagram used to explain the control plane process of L2 U2N relay (UE to UE relay).

[0053] Figure 15 and Figure 16This is a schematic diagram used to explain the UE-to-UE (U2U) relay selection process without relay discovery.

[0054] Figure 17 This provides an illustrative example of the planar protocol stack for L2 U2N relays.

[0055] Figure 18 This is a schematic diagram illustrating the discovery process of a multi-hop relay operation.

[0056] Figure 19 This is a schematic diagram illustrating a method for configuring discovery messages in multi-hop relay operations.

[0057] Figure 20 This is a schematic diagram illustrating a method for a relay UE to forward discovery messages for multi-hop relay.

[0058] Figure 21 This is a schematic diagram illustrating a method by which the first device sends a discovery message for multi-hop relay.

[0059] Figure 22 An example of a communication system applied to this disclosure is shown.

[0060] Figure 23 Wireless devices applicable to this disclosure are illustrated.

[0061] Figure 24 Another example of a wireless device that applies the present disclosure is illustrated.

[0062] Figure 25 Examples of vehicles or autonomous vehicles applicable to this disclosure are shown. Detailed Implementation

[0063] Wireless communication systems are multiple access systems that support communication with multiple users by sharing available system resources (e.g., bandwidth, transmit 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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, including low-frequency bands below 1 GHz, mid-frequency bands between 1 GHz and 10 GHz, and high-frequency (millimeter-wave) bands of 24 GHz and above.

[0069] For clarity, the description primarily focuses on LTE-A or 5G NR, but the technical spirit of the implementation is not limited thereto.

[0070] Figure 2 An example of the structure of an LTE system applicable to 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.

[0071] Reference Figure 2 E-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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] Figure 3 The structure of an NR system applicable to this disclosure is illustrated.

[0076] 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.

[0077] Figure 4 The structure of an NR radio frame applicable to this disclosure is illustrated.

[0078] Reference Figure 4 Radio frames can be used for UL and DL transmissions in NR. A radio frame is 10 ms long and can be defined by two 5 ms half-frames. HF can include five 1 ms 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).

[0079] 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).

[0080] Table 1 below lists the number of symbols N per slot in the NCP case based on the SCS configuration μ. slot symb The number of time slots per frame, N frame,u slot and the number of time slots N in each subframe subframe,u slot .

[0081] [Table 1]

[0082]

[0083] 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.

[0084] [Table 2]

[0085]

[0086] 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.

[0087] In NR, various parameter sets or SCSs can be supported to support a wide range of 5G services. For example, a 15 kHz SCS can support wide areas in traditional cellular bands, while a 30 kHz / 60 kHz SCS can support dense urban areas, lower latency, and wider carrier bandwidth. When the SCS is 60 kHz or higher, bandwidths wider than 24.25 GHz can be supported to overcome phase noise.

[0088] The NR band can be defined by two types of frequency ranges, 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 the NR system, 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).

[0089] [Table 3]

[0090]

[0091] As mentioned above, the frequency range of the NR system can be changed. For example, FR1 can include a frequency band from 410 MHz to 7125 MHz as shown in Table 24 below. That is, FR1 can include a frequency band of 6 GHz (or 5850 MHz, 5900 MHz, 5925 MHz, etc.) or higher. For example, the frequency band of 6 GHz (or 5850 MHz, 5900 MHz, 5925 MHz, etc.) or higher included in FR1 can include unlicensed frequency bands. Unlicensed frequency bands can be used for various purposes, such as for vehicle communications (e.g., autonomous driving).

[0092] [Table 4]

[0093]

[0094] Figure 5The time slot structure of an NR frame applicable to this disclosure is illustrated.

[0095] Reference Figure 5 A time slot comprises 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.

[0096] 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.

[0097] The radio interface between UEs or between a UE and the network may include layers L1, L2, and L3. In various embodiments of this disclosure, layer L1 may represent the physical layer. Layer L2 may, for example, represent at least one of the MAC layer, RLC layer, PDCH layer, or SDAP layer. Layer L3 may, for example, represent the RRC layer.

[0098] 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. Figure 6 The implementation methods can be combined with various implementation methods of this disclosure.

[0099] In 6G, new network features may include the following.

[0100] - Integrated satellite network

[0101] - 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).

[0102] - Seamless integration of wireless information and power transfer

[0103] - 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.

[0104] Regarding the new 6G network features described above, some general requirements may include the following:

[0105] - Small Cellular Network

[0106] - Ultra-dense heterogeneous networks

[0107] - High-capacity backhaul

[0108] - 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.

[0109] - Softwareization and Virtualization

[0110] The key implementation technologies of 6G systems will be described below.

[0111] - 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.

[0112] 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.

[0113] Figure 7 An electromagnetic spectrum according to an embodiment of the present disclosure is illustrated. Figure 7The 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 (BS) operating in this frequency band. This enables the use of advanced adaptive array techniques that overcome distance limitations.

[0114] - Massive MIMO technology

[0115] - Holographic Beamforming (HBF)

[0116] - Optical wireless technology

[0117] - Free Space Optics (FSO) Backhaul Network

[0118] - Quantum communication

[0119] - Cellular communication

[0120] - Integration of wireless information and power transmission

[0121] - Integration of wireless communication and sensing

[0122] - Integrated access and backhaul networks

[0123] Big Data Analytics

[0124] - Reconfigurable smart surfaces

[0125] - Metaverse

[0126] - Blockchain

[0127] - 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.

[0128] - 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.

[0129] Figure 8 An example of a radio protocol architecture used for SL communication is given. Specifically, Figure 8 (a) shows the NR user plane protocol stack, and Figure 8 (b) shows the NR control plane protocol stack.

[0130] The following text will describe the side link synchronization signal (SLSS) and synchronization information.

[0131] As SL-specific sequences, SLSS 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-SSSS. 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 detailed synchronization and detect the synchronization signal ID.

[0132] The Physical Sidelink Broadcast Channel (PSBCH) can be a (broadcast) channel used to transmit basic (system) information that the UE needs to know before SL signal transmission and reception. For example, basic information may include information related to SLSS, duplex mode (DM), time-division duplex uplink / downlink (TDD) UL / DL configuration, resource pool information, application type related to 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.

[0133] S-PSS, S-SSS, and PSBCH can be included in a block format that supports periodic transmission (e.g., an SL synchronization signal (SS) / PSBCH block, referred to below as a 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) on the carrier, and its transmission bandwidth can be within a pre-set SL BWP. For example, the S-SSB can have a bandwidth of 11 RBs. Similarly, the PSBCH can span 11 RBs. Furthermore, the frequency location of the S-SSB can be pre-set. Therefore, the UE does not need to perform frequency hypothesis detection to discover the S-SSB on the carrier.

[0134] 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 the time resource for the transmitting UE to transmit S-SSBs can be shortened. Therefore, the S-SSB coverage 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 160 ms. For example, a 160 ms S-SSB transmission period can be supported for all SCSs.

[0135] For example, when the SCS is 15 kHz 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 30 kHz 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 60 kHz in FR1, the transmitting UE can send one, two, or four S-SSBs to the receiving UE within one S-SSB transmission period.

[0136] For example, when the SCS is 60 kHz 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 120 kHz 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.

[0137] When the SCS is 60 kHz, 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 10. 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.

[0138] Figure 9An example of a UE performing V2X or SL communication is shown.

[0139] 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.

[0140] For example, UE 1 can select a resource element corresponding to a specific resource from a resource pool (which represents a resource set). Then, UE 1 can transmit an SL signal through the 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 in the resource pool.

[0141] Here, when UE 1 is within the BS's connection range, the BS can notify UE 1 of the resource pool. On the other hand, when UE 1 is outside the BS's connection range, another UE can notify UE 1 of the resource pool, or UE 1 can use a pre-configured resource pool.

[0142] 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.

[0143] Figure 10 Examples of resource units for V2X or SL communication are shown.

[0144] Reference Figure 10 The 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*NT resource units can be defined in the resource pool. Figure 10 An exemplary case of a periodically repeating resource pool with NT subframes is shown.

[0145] like Figure 10 As shown, a resource element (e.g., element #0) can appear periodically and repeatedly. Alternatively, to achieve diversity effects in the time or frequency dimension, the index of the physical resource element to which a logical resource element is mapped can change over time in a predetermined pattern. In this structure of resource elements, a resource pool can represent the set of resource elements available to a UE intended to transmit SL signals.

[0146] 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.

[0147] (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 for demodulating 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 refer to the resource pool where SA and SL data are multiplexed and transmitted. SA can be called the SL control channel.

[0148] (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.

[0149] (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.

[0150] Even when 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 when the SL data channel or discovery message is the same in the signal, they can be classified into different resource pools based on 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., determined by the number of symbols occupied by each SL signal in a subframe, or the number of subframes used for the transmission of one SL signal), signal strength from the BS, transmission power of the SL UE, etc.

[0151] 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.

[0152] Reference Figure 11A 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.

[0153] 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.

[0154] The following describes V2X or SL communication. SLSS is a dedicated SL sequence and can include a primary sidelink synchronization signal (PSSS) and a secondary sidelink synchronization signal (SSSS). PSSS can be called the primary sidelink synchronization signal (S-PSS), and SSSS can be called 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.

[0155] The Physical Sidelink Broadcast Channel (PSBCH) can be a (broadcast) channel used to transmit basic (system) information that a UE needs to know before sending and receiving SL signals. For example, this 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, the PSBCH payload size in NR V2X can be 56 bits, including a 24-bit CRC.

[0156] 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 sidelink bandwidth portion (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.

[0157] 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.

[0158] Reference Figure 12 In step (a), under LTE transmission mode 1, LTE transmission mode 3, or NR resource allocation mode 1, the base station can schedule SL resources for the UE to use for SL transmission. For example, in step S1200, the base station can send information associated with SL resources and / or information associated with uplink (UL) resources to the first terminal. For example, UL resources may include Physical Uplink Control Channel (PUCCH) resources and / or Physical Uplink Shared Channel (PUSCH) resources. For example, UL resources may be resources used to report SL HARQ feedback to the base station.

[0159] For example, the first UE may receive information from the base station relating to Dynamic Grant (DG) resources and / or Configuration Grant (CG) resources. For example, CG resources may include CG Type 1 resources or CG Type 2 resources. In this disclosure, DG resources may be resources configured / assigned by the base station to the first UE via Downlink Control Information (DCI). In this disclosure, CG resources may be (periodic) resources configured / assigned by the base station to the first UE via DCI and / or RRC messages. For example, in the case of CG Type 1 resources, the base station may send an RRC message to the first UE including information relating to the CG resources. For example, in the case of CG Type 2 resources, the base station may send an RRC message to the first UE including information relating to the CG resources, and the base station may send a DCI relating to the activation or release of the CG resources to the first UE.

[0160] In step S1210, 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., Negative Acknowledgment (NACK) or Acknowledgment (ACK)) 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.

[0161] Reference Figure 12 (b) In Long Term Evolution (LTE) Transport Mode 2, LTE Transport Mode 4, or NR Resource Allocation Mode 2, the UE can determine SL transport resources within SL resources configured by the base station / network or pre-configured SL resources. For example, the configured SL resources or pre-configured SL resources 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 perform a sensing and resource selection (reselection) process to autonomously select resources within a selection window. For example, sensing can be performed on a sub-channel basis. For example, in step S1210, the first UE, having selected resources in the resource pool, can use the 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 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 PSFCH related to PSCCH / PSSCH from the second UE.

[0162] Reference Figure 15 (a) or Figure 15(b) For example, the first UE may send an SCI to the second UE on the PSCCH. Alternatively, for example, the first UE may send two consecutive SCIs (e.g., two-level SCIs) to the second UE on the PSCCH and / or PSSCH. In this case, the second UE may decode the two consecutive SCIs (e.g., two-level SCIs) to receive the PSSCH from the first UE. In this disclosure, an SCI sent on the PSCCH may be referred to as 1st SCI, first SCI, first-level SCI, or first-level SCI format, and an SCI sent on the PSSCH may be referred to as 2nd SCI, second SCI, or second-level SCI format.

[0163] Reference Figure 12 In either (a) or (b), in step S1530, 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.

[0164] 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.

[0165] The SL mentioned above can be defined as device-to-device (D2D) communication or direct communication between UEs. In this case, PSCCH can be defined as a physical control channel for direct communication between UEs, PSSCH can be defined as a physical data channel or physical shared channel for direct communication between UEs, and PSFCH can be defined as a physical feedback transmission channel for direct communication between UEs.

[0166] Figure 13 This is a diagram used to explain the control plane procedures of L2 U2N relay (UE to network relay).

[0167] 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.

[0168] When a remote UE delivers its first RRC message to establish a connection with the gNB, whether within or outside coverage, the PC5 L2 configuration used for transmission 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.

[0169] The specific scenario (TS 38.300) describes the control plane procedures used for L2 U2N relays, as illustrated in Table 5 below.

[0170] [Table 5]

[0171]

[0172]

[0173] In the above scenario, for L2 U2N trunks, apart from the connection establishment process:

[0174] - For RRC reconfiguration and RRC connection release processes, traditional RRC procedures can be reused, and message content / configuration design is left to be determined in the WI phase.

[0175] - For RRC reconfiguration and RRC connection release procedures, the traditional RRC procedure can be reused as a baseline by considering the connection establishment procedure of the L2 U2N trunk described above to handle the trunk-specific portion and message content / configuration. Message content / configuration will be defined later.

[0176] Figure 14 This is a schematic diagram illustrating the control plane process of L2 UE to UE (U2U) relay.

[0177] The control plane procedures for L2 U2U relays can be defined as shown in Table 6 below.

[0178] [Table 6]

[0179]

[0180]

[0181] Here, the PC5 connection or direct connection between the U2U remote UE and the U2U relay UE can be defined as the first hop connection, and the PC5 connection or direct connection between the U2U relay UE and the peer U2U remote UE (or the target remote UE) can be defined as the second hop connection.

[0182] The following section describes a method for performing U2U relay selection without a discovery process.

[0183] Figure 15 and Figure 16 This is a schematic diagram used to explain the process of UE-to-UE (U2U) relay selection without relay discovery.

[0184] Referring to a specific scenario (Section 6.8 of TR 23.752), when a source UE wishes to communicate with a target UE, the source UE can first attempt to discover the target UE by sending a Direct Communication Request or a Solicitation message that includes information related to the target UE. If the source UE cannot directly reach the target UE, it can attempt to discover a U2U relay used to reach the target UE, which can also trigger the relay to discover the target UE. The source UE can integrate the discovery of the target UE and / or the discovery / selection of the U2U relay based on the following two alternative schemes.

[0185] - Alternative Option 1: The discovery / selection of U2U relays can be integrated into the unicast link establishment process (see Section 6.3.3 of TS23.287).

[0186] - Alternative Option 2: Discovery / selection of U2U relays can be integrated into the Mode B direct discovery process.

[0187] To indicate whether a relay can be used for communication, a new field can be added to the direct communication request or request message. This new field can be defined as Relay_indication. If the (source) UE intends to broadcast a direct communication request or request message, the request message can include Relay_indication to indicate whether a U2U relay can be used. For Release 17, it can be assumed that the value of Relay_indication is limited to a single hop.

[0188] If a U2U relay receives a request message configured with Relay_indication, the U2U relay can determine whether to forward the request message (i.e., modify the message and broadcast it in its vicinity). For example, the U2U relay can determine whether to forward the request message based on factors such as: the relay service code (if present), the application ID, the authorization policy (e.g., for a relay using a specific ProSe service), the relay's current traffic load, and the radio conditions between the source UE and the relay UE.

[0189] Alternatively, multiple U2U trunks can be used to reach the target UE (Scenario 1), or the target UE can receive the request message directly from the source UE (Scenario 2). In this case, the target UE can choose to respond in Scenario 1 or Scenario 2. For example, the target UE can choose to respond in Scenario 1 or Scenario 2 based on factors such as signal strength, local policies (e.g., traffic load of the U2U trunk), trunk service code (if present), and / or operator policies (e.g., always prioritizing direct communication or selectively using a specific U2U trunk).

[0190] Alternatively, the source UE may receive a response to the request message from multiple U2U trunks, or it may receive a response to the request message directly from the target UE. In this case, the source UE may select a communication path (direct path or indirect path) based on signal strength or operator policies (e.g., always prioritizing direct communication or selectively using a specific U2U trunk).

[0191] Specifically, the above alternative solutions can be referred to in Table 7 and Figure 15 This is achieved through the description.

[0192] [Table 7]

[0193]

[0194]

[0195]

[0196] Alternative option 2 mentioned above can be found in Table 8 below. Figure 16 The implementation.

[0197] [Table 8]

[0198]

[0199]

[0200] Figure 17 This is a schematic example of the protocol stack for L2 U2U relay.

[0201] Figure 17 (a) illustrates the user plane protocol stack of an L2 U2U relay, while Figure 17 Example (b) illustrates the control plane protocol stack for L2 U2U relays. Table 9 shows... Figure 17 The details of the L2 relay architecture and protocol stack are shown.

[0202] [Table 9]

[0203]

[0204]

[0205] Regarding relay communication, there can be two models, Model A and Model B, for the discovery process. In a specific scenario (3GPP 23.304), the definition of Model A is shown in Table 10 below, and the definition of Model B is shown in Table 11 below.

[0206] [Table 10]

[0207]

[0208]

[0209] [Table 11]

[0210]

[0211]

[0212] The above text combined Figures 13 to 17 The previous section described the U2U and U2N relay operations and discovery process based on a single hop (i.e., using one relay UE). However, U2U and U2N relay operations can also be performed using multiple relay UEs in a multi-hop manner. Therefore, the following section will describe in detail the method of performing U2U and U2N relay operations based on multiple relay UEs in a multi-hop manner.

[0213] The multi-hop relay operations described below are applicable not only to U2U relay operations but also to U2N relay operations. For example, the methods presented below can be applied to U2N relay operations simply by replacing the source or target remote UE with a base station (BS) (or network). For ease of description, the following explanations are primarily based on the context of U2U relay operations.

[0214] Discovery process of multi-hop relay operation

[0215] Figure 18 This is a schematic diagram illustrating the discovery process of a multi-hop relay operation.

[0216] 1. Sending discovery messages (operations of discovery models A / B and integrated discovery models)

[0217] In single-hop U2U relay operation, discovery model A can be a scenario where the relay UE sends a discovery message including a list of IDs of accessible target remote UEs. Here, "accessible" means that the signal strength (e.g., SD-RSRP) between the relay UE and the target remote UE is greater than or equal to a predetermined threshold. The ID list can include the IDs of target remote UEs whose signal strength with the relay UE is greater than or equal to the threshold. When the discovery message broadcast by the relay UE includes a target remote UE that the source remote UE expects to reach, the source remote UE can select the relay UE and perform connection establishment-related operations to achieve communication with the target remote UE.

[0218] In multi-hop U2U relay operations, the discovery message sent (or broadcast) by each relay UE may include the hop count required to reach the target remote UE. And / or, the discovery message sent (or broadcast) by each relay UE may include the IDs (or a list of IDs) of other relay UEs required to reach the target remote UE, information about the hop count of the relay UEs (corresponding to IDs included in the ID list) to reach the target remote UE, and the relay UE ID corresponding to each hop. For example, refer to... Figure 18 (a) Relay UE 2 may send a discovery message including hop count 1, relay UE 3 may send a discovery message including hop count 2 and / or the ID of relay UE 4, and relay UE 4 may send a discovery message including hop count 1. (and / or) if the message passes through several other relay UEs, the discovery message may also include the SL RSRP (or SD-RSRP) value measured by each relay UE. The SL RSRP (or SD-RSRP) value measured by each relay UE may include the signal strength between the relay UE and the target remote UE, and / or the signal strength between the relay UE and other relay UEs required to reach the target remote UE. Alternatively, the discovery message may include a key value (e.g., a maximum or minimum value) of the signal strength between the relay UE and other relay UEs required to reach the target remote UE as a representative value.

[0219] Alternatively, when the hop count required to reach the target remote UE varies depending on the relay UE, the discovery message may include only the minimum hop count among the multiple relay UEs. For example, refer to Figure 18(b) Relay UE 5 can determine, through the discovery message received from relay UE 2, that a two-hop connection or two hops are required to reach the target remote UE, and through the discovery message received from relay UE 3, recognize that a three-hop connection or three hops are required to reach the target remote UE. In this case, relay UE 5 can send a discovery message that includes the smaller value of 2 in the hop count (2 hops, 3 hops) as the (representative) hop count value. In this case, the discovery message can also include the ID of the other relay UEs connected (i.e., the ID of relay UE 2 with the smaller hop count value of 2 among the IDs of relay UE 2 and relay UE 3). For example, the discovery message of relay UE 5 can include the hop count value of 2 to the target remote UE, and the ID of relay UE 2 as the ID of the other relay UEs connected.

[0220] Alternatively, a relay UE may increment the hop count in a discovery message received from another relay UE and forward / send a discovery message with the incremented hop count. In this case, if the hop count included in the discovery message that the relay UE is about to send / forward (e.g., the hop count after incrementing by 1) is greater than or equal to a predefined threshold hop count, the relay UE may discard the discovery message without forwarding it. This is because the hop count required to send the message from the source remote UE (or the target remote UE) to the target remote UE (or the source remote UE) is too large, which may not meet latency requirements. For example, when the hop count (or the hop count after incrementing by 1) in a discovery message of a particular relay UE is greater than or equal to a predefined threshold hop count, the relay UE may discard the discovery message of that particular relay UE without forwarding it. Furthermore, the relay UE may exclude the ID of that particular relay UE from the list of relay UEs included in its own discovery messages.

[0221] In this case, the predefined threshold hop can be predefined via RRC-specific messages and / or SIBs. Alternatively, the value of the predefined threshold hop can be defined differently based on Quality of Service (QoS) and / or Packet Delay Budget (PDB) requirements. Alternatively, the predefined threshold hop can be a value determined by the higher layers of the source remote UE, the target remote UE (or the relay UE). For example, the higher layer of the source remote UE can determine a specific hop count value that satisfies the QoS and / or PDB requirements of the messages it wants to send via multi-hop relay, and send a discovery message including that specific hop count value as the predefined threshold hop. When it is determined that incrementing the hop count in the received discovery message by 1 does not satisfy the predefined threshold hop, the relay UE may not forward the discovery message.

[0222] Alternatively, when the source remote UE determines the required maximum total hop count (or when the source remote UE directly predetermines / predefines the maximum hop count, or when it is predetermined / predefined by an SIB / dedicated RRC message / preconfiguration), the source remote UE may send a discovery message including that maximum hop count. In this case, the relay UE may forward the discovery message with a hop count value obtained by subtracting 1 from the hop count value included in the received discovery message. When the hop count value in the received discovery message is 0 after subtracting 1, the relay UE may no longer send / forward the received discovery message. This is because when the maximum hop count has been exceeded, the multi-hop relay path is very likely to fail to meet the QoS (or PDB) requirements expected by the source remote UE.

[0223] Alternatively, when a source remote UE or a target remote UE receives multiple discovery messages with a receive strength (RSRP) greater than or equal to a threshold strength, the source remote UE or the target remote UE may (only) send a response message to the relay UE corresponding to the discovery message with the smallest hop count among the multiple discovery messages.

[0224] Alternatively, a specific relay UE may receive discovery messages for the same source / target remote UE through different relay UEs. For example, after relay UE 1 receives and forwards a discovery message for a source or target remote UE from relay UE A, it then receives another discovery message for the same source or target remote UE from relay UE B. In this case, relay UE 1 may forward the discovery message from relay UE B only if the cumulative hop count of the discovery message received from relay UE B is less than (or greater than) the cumulative hop count of the previously forwarded discovery message from relay UE A. Alternatively, relay UE 1 may forward the discovery message from relay UE B only if the remaining allowed hop count of the discovery message from relay UE B (i.e., the maximum hop count mentioned above, decreasing by 1 after each hop) is greater than (or less than) the remaining allowed hop count of the previously forwarded discovery message from relay UE A. In other words, when a relay UE receives discovery messages for the same source remote UE or target remote UE sequentially, the relay UE can only forward the later-received discovery message if the hop count comparison result indicates that its latency quality is better than the previously forwarded discovery message. Conversely, if the subsequent discovery message has worse latency quality (e.g., a higher hop count), the relay UE can discard forwarding the subsequent discovery message.

[0225] In this way, the proposed method can determine whether to forward the received discovery message based on the hop count included in the discovery message, thereby preventing the discovery message from being over-spread in multi-hop relay communication.

[0226] As described above, in the proposed method, the roles of the source remote UE and the target remote UE can be interchanged. Furthermore, since the proposed method can also be applied to multi-hop U2N relays, it is clear that this scheme can be applied by replacing either the source remote UE or the target remote UE with a network (gNB).

[0227] Although the methods described above are presented in various implementations within the context of discovery messages, this is merely for illustrative purposes. These methods can obviously also be applied to Direct Communication Request (DCR) / Direct Communication Acceptance (DCA) messages, SL RRC messages (e.g., RRCReconfigurationSidelink or RRCReconfigurationCompleteSidelink), discovery response messages, and / or general data transmission messages. For example, various messages used in multi-hop relay communication can additionally include a hop count value, allowing the relay UE to specify / determine the message to be forwarded based on the hop count included in the message. Alternatively, the PC5 RRC message applying the above disclosure can also be limited to the initial RRC message (RRCReconfigurationSidelink or RRCReconfigurationCompleteSidelink).

[0228] The following section describes in detail the method by which a relay UE determines whether to forward a received message based on the sequence number.

[0229] Discovery message configuration for multi-hop relay operations

[0230] Figure 19 This is a schematic diagram illustrating the discovery message configuration method for multi-hop relay operations.

[0231] When discovery messages are transmitted via multiple hops or multiple relay UEs, a single discovery message may be received multiple times by the target remote UE. This redundant reception and transmission of a single discovery message increases channel load and may also cause confusion for the target remote UE when responding to the discovery message.

[0232] For example, refer to Figure 19In (a), the source remote UE can send a discovery message to discover the target remote UE. When the source remote UE sends discovery message 1, the target remote UE may receive discovery message 1 via relay path 1 through relay UE 1 and relay UE 2, and via relay path 2 through relay UE 2 only. In this case, relay UE 2 needs to be controlled to ensure that the single discovery message sent by the source remote UE is sent / forwarded to the target remote UE only once. To achieve this, relay UE 2 needs to identify whether the discovery message received from relay UE 1 is the same message as the discovery message received from the source remote UE. To achieve this, the discovery message may (additionally) include a sequence number. For example, the source remote UE may send a discovery message that includes a specific sequence number. In this case, the relay UE can identify whether the previously received discovery message and the subsequently received discovery message are the same discovery message based on the specific sequence number included in the received discovery message.

[0233] Alternatively, refer to Figure 19 (b) The source remote UE (or base station) may send a discovery message twice for the same target remote UE. These two discovery messages may be sent to relay UE 2 via different paths. In this case, even if the two discovery messages are for the same source and target remote UE, relay UE 2 can identify them as different discovery messages based on the sequence numbers included in the discovery messages. In this case, relay UE 2 needs to forward each of the two discovery messages. For example, discovery message 1 and discovery message 2 may include different sequence numbers, and relay UE 2 can determine, based on the sequence number of each message, that even if the two discovery messages are for the same target remote UE, they are different discovery messages. In this case, relay UE 2 can forward each of the two discovery messages to the target remote UE.

[0234] In this way, the proposed method allows intermediate relay UEs in multi-hop relay operations to conveniently determine / identify whether a newly received discovery message is the same as a previously forwarded discovery message by using the sequence number, even if they receive multiple discovery messages through different relay paths.

[0235] Although the methods described above are presented in various implementations within the context of discovery messages, this is merely for illustrative purposes. These methods can obviously also be applied to Direct Communication Request (DCR) / Direct Communication Acceptance (DCA) messages, SL RRC messages (e.g., RRCReconfigurationSidelink or RRCReconfigurationCompleteSidelink), discovery response messages, and / or general data transmission messages. For example, various messages used in multi-hop relay communication can additionally include sequence number information, allowing the relay UE to specify / determine the messages to be forwarded based on the sequence numbers included in the messages.

[0236] The following section describes in detail how a relay UE determines whether to forward a received discovery message based on the timestamp and time budget included in the discovery message.

[0237] Considering the PDB discovery process in multi-hop relay operations

[0238] The following description applies to operations related to discovery model A, discovery model B, or integrated discovery model as described above. Furthermore, as mentioned above, the following description also applies to multi-hop U2N relay operations when the source or target remote UE is replaced by a network.

[0239] Discovery messages sent by the source remote UE (or target remote UE) and / or relay UE performing multi-hop relay operations may include a timestamp and a time budget value. The timestamp may indicate the time the discovery message was sent, and the time budget may indicate the (remaining) PDB value. The timestamp and / or time budget value may be included in discovery messages, discovery response messages, DCR / DCA messages, and / or SL RRC messages used to establish (initial) SL connections (e.g., RRCReconfigurationSidelink or RRCReconfigurationCompleteSidelink). Alternatively, the timestamp and / or time budget value may also be included in general data transmission messages.

[0240] The timestamp and / or time budget values ​​mentioned above can be included in the higher layers that generate the PC5-S / discovery message, but when used for general data transmission or SL RRC connections, they can also be included in the header of either the AS layer adapter layer or the MAC / RLC / PHY layer. Alternatively, even when sending a discovery message, the timestamp and / or time budget values ​​can be included in the header of either the AS layer adapter layer or the MAC / RLC / PHY layer used to send the discovery message.

[0241] Specifically, when using timestamps and time budget values, the following operations can be performed.

[0242] For example, a discovery message sent by the source remote UE may include a timestamp for the transmission time, and the PDB value or (initial) time budget required to send the message to the target remote UE (and / or the maximum / minimum latency required for a multi-hop discovery message to reach the target remote UE). The receiving (candidate) relay UE may replace the timestamp value in the discovery message with its own timestamp and replace the existing time budget with the remaining time budget. The remaining time budget may be the residual value obtained by subtracting the difference between the source timestamp and its own timestamp from the time budget included in the discovery message. In this case, the (candidate) relay UE may forward the discovery message with the replaced timestamp and time budget. Alternatively, when the time budget or remaining time budget included in the discovery message becomes 0 (or less than a threshold time budget value, or is negative), the relay UE may discard the discovery message without forwarding it.

[0243] The initial value of the time budget (e.g., a time budget value determined / set by the source remote UE) can be set via SIB / pre-configuration / RRC dedicated messages, or it can be configured to select one of multiple values ​​based on QoS. Alternatively, the time budget value can be determined by a higher layer of the source remote UE.

[0244] Alternatively, the discovery message may include information about timestamps and cumulative elapsed time. For example, the discovery message may include a timestamp of the transmission time of the source remote UE, and information about the cumulative elapsed time consumed by each relay UE. When the cumulative elapsed time is greater than or equal to a threshold cumulative time, the relay UE may discard the received discovery message and stop forwarding it. Similar to time budgeting, the threshold cumulative time can be set differently depending on the QoS.

[0245] Alternatively, a relay UE may receive discovery messages from multiple other relay UEs targeting the same source remote UE (and / or target remote UE). In this case, the relay UE may forward only the specific discovery message with the largest remaining time budget among these discovery messages (or, if cumulative time is used, forward the specific discovery message with the smallest cumulative time consumption), and store the ID of the specific relay UE that sent the specific discovery message. Alternatively, the relay UE may forward discovery messages that only include the ID of the specific relay UE that sent the specific discovery message. Data transmission by sending the specific relay UE with the largest remaining time budget can have the lowest latency. Therefore, the relay UE may pre-store the ID of the specific relay UE for use in relay selection during relay communication based on the specific discovery message. The relay UE may replace the timestamp and time budget included in the specific discovery message with its own timestamp and remaining time budget. As mentioned above, the remaining time budget can be the remaining value obtained by subtracting the difference between the timestamp included in the specific discovery message and its own timestamp from the time budget included in the specific discovery message.

[0246] Alternatively, the relay UE may first consider the hop count included in discovery messages targeting the same source remote UE (and / or target remote UE), and then consider the (remaining) time budget included in the discovery messages. For example, the relay UE may receive multiple discovery messages. In this case, the relay UE may first identify the hop count included in each discovery message and prioritize forwarding the discovery message with the smallest hop count. When two or more discovery messages have the same hop count, the relay UE may forward only the specific discovery message that includes the largest (remaining) time budget among the two or more discovery messages (or, if cumulative time is used, forward the specific discovery message with the smallest cumulative time). The relay UE may store the ID of the relay UE that sent the specific discovery message.

[0247] Alternatively, the relay UE may first consider the (remaining) time budget included in the discovery message for the same source remote UE (and / or target remote UE), and then consider the hop count. For example, the relay UE may (preferably) forward only the discovery message with the largest remaining time budget among multiple discovery messages. Alternatively, when there are two or more discovery messages with a remaining time budget greater than or equal to a specific threshold budget, the relay UE may forward only the discovery message with the smallest hop count among the two or more discovery messages. The relay UE may store the ID of the relay UE that sent the discovery message to be forwarded (in its own memory). The discovery messages for the same source remote UE (and / or target remote UE) may be messages received sequentially by the relay UE within a specific time period.

[0248] In this way, the proposed method ensures that in multi-hop relay operations, the forwarding of discovery messages or the selection of candidate relay UEs is only performed if communication can be completed within a given time budget from the source remote UE (or BS) to the target remote UE (or BS).

[0249] Although the methods described above are presented in various implementations within the context of discovery messages, this is merely for illustrative purposes. These methods can obviously also be applied to DCR / DCA messages, SL RRC messages (e.g., RRCReconfigurationSidelink or RRCReconfigurationCompleteSidelink), discovery response messages, and / or general data transmission messages. For example, various messages used in multi-hop relay communication can additionally include the aforementioned information regarding timestamps and time budgets, allowing the relay UE to specify / determine the messages to be forwarded based on the timestamps and time budgets included in the messages.

[0250] Figure 20 This is a schematic diagram illustrating a method for a relay UE to forward discovery messages based on multi-hop relay forwarding.

[0251] Reference Figure 20 The relay UE can receive a first discovery message (or discovery signal) for multi-hop relay (S201). As described above, multi-hop relay can refer to relay communication in which multiple relay UEs send and receive messages between a first device (or source device) and a second device (or target device). The first device can be a remote UE (or source remote UE) or a network, and the second device can be a remote UE (or target remote UE) or a network. For example, multi-hop relay can be multi-hop U2N relay for sending and receiving data between a remote UE and a network, or multi-hop U2U relay for sending and receiving data between a source remote UE and a target remote UE. The first discovery message can be a message sent or forwarded by other relay UEs, or it can be a message sent by the source device (or target device).

[0252] Subsequently, the relay UE can determine whether to forward the first discovery message based on the first timestamp and time budget included in the first discovery message (S203). The first timestamp is information about the time when the first discovery message was sent or forwarded, and the time budget can be information about the time required for the first discovery message to reach the second device. The initial value of the first timestamp can be the time when the first device sent the first discovery message, and the initial value of the time budget can be determined based on the QoS of the data or message that the first device wants to send to the second device.

[0253] Specifically, the relay UE can determine whether to forward the first discovery message based on the difference between the first timestamp and its own timestamp, and a time budget. For example, when the remaining time budget obtained by subtracting the difference from the time budget is greater than or equal to a specific threshold, the relay UE can forward the first discovery message. Conversely, when the remaining time budget obtained by subtracting the difference from the time budget is less than the specific threshold, the relay UE can choose not to forward the first discovery message. The specific threshold can be 0, or it can be determined differently based on the split QoS or split PDB associated with the relay UE.

[0254] Alternatively, the time budget included in the first discovery message may be a cumulative elapsed time. In this case, if the cumulative elapsed time obtained by adding the time budget to the difference between the first and second timestamps is less than a specific cumulative threshold, the relay UE may forward the first discovery message. Conversely, if the cumulative elapsed time obtained by adding the time budget to the difference is greater than or equal to the specific cumulative threshold, the relay UE may not forward the first discovery message. The specific cumulative threshold may be determined based on the QoS of the message to be sent between the first and second devices.

[0255] Subsequently, based on the remaining time budget being greater than or equal to a specific threshold, the relay UE can forward the first discovery message (S205). Specifically, the relay UE can forward the first discovery message after replacing the first timestamp with its own timestamp, i.e., the second timestamp, and replacing the time budget with the remaining time budget.

[0256] Alternatively, the relay UE may receive a second discovery message after forwarding a first discovery message. When the source device and target device of the second discovery message are the same as those of the first discovery message, the relay UE may determine whether to forward the second discovery message based on the hop count, sequence number, and / or time budget included in the first and second discovery messages. For example, the relay UE may forward the second discovery message only if the second sequence number included in the second discovery message is different from the first sequence number included in the first discovery message. Alternatively, the relay UE may forward the second discovery message only if the second hop count included in the second discovery message is less than the first hop count included in the first discovery message. Alternatively, the relay UE may forward the second discovery message only if the time budget included in the second discovery message is greater than the time budget included in the first discovery message (or less than the time budget included in the first discovery message if the time budget is the cumulative elapsed time). Alternatively, the relay UE may consider the hop count of the second discovery message first and then consider the time budget of the second discovery message. For example, even if the time budget of the second discovery message is greater than that of the first discovery message, the relay UE can still discard the second discovery message without forwarding it if the hop count of the second discovery message is greater than that of the first discovery message. Alternatively, the relay UE can consider the time budget of the second discovery message first, and then consider the hop count of the second discovery message.

[0257] Figure 21 This is a schematic diagram illustrating the method by which the first device sends discovery messages for multi-hop relays.

[0258] Reference Figure 21 The first device may send a discovery message for connecting to the second device via a multi-hop relay (S211). The first device may be a source remote UE or a network, and the second device may be a target remote UE.

[0259] Subsequently, the first device may receive a response message in response to the discovery message (S213). The response message may be a message sent by the second device through a multi-hop relay or multiple relay UEs.

[0260] Subsequently, the first device can establish a connection with the second device via multi-hop relay based on the response message (S215).

[0261] By sending discovery messages that include timestamps and time budgets in this manner, the proposed disclosure ensures that only relay UEs capable of forming multi-hop relays within the time budget will forward discovery messages. Alternatively, the proposed disclosure can prevent over-forwarding of discovery messages in multi-hop relay communications. Alternatively, the proposed disclosure can prevent redundant forwarding of single discovery messages for the same source and target devices by sending discovery messages that include hop counts or sequence numbers.

[0262] Example of a communication system using this disclosure

[0263] 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.

[0264] 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.

[0265] Figure 22 An example of a communication system applied to this disclosure is shown.

[0266] Reference Figure 22 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.

[0267] 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.

[0268] 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.

[0269] Examples of wireless devices using this disclosure

[0270] Figure 23 Wireless devices applicable to this disclosure are illustrated.

[0271] Reference Figure 23 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 22 {Wireless Device 100x and BS 200} and / or {Wireless Device 100x and Wireless Device 100x}.

[0272] 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.

[0273] Specifically, the first wireless device or 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 18 to 21 The operations related to each of the described implementation methods.

[0274] The processor 102 can control the transceiver 106 to receive a first discovery message for multi-hop relay, and determine whether to forward the first discovery message based on the first timestamp and time budget included in the first discovery message.

[0275] 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 connected to the at least one processor and storing instructions that, when executed by the at least one processor, cause the relay UE to receive a first discovery message for multi-hop relay and determine whether to forward the first discovery message based on a first timestamp and time budget included in the first discovery message.

[0276] 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.

[0277] Specifically, the second wireless device or BS 200 may include a processor 202 connected to the transceiver or RF transceiver 206, and a memory 204. The memory 204 may include at least one program for executing combined... Figures 18 to 21 The operations related to each of the described implementation methods.

[0278] The processor 202 can control the transceiver 206 to send a discovery message for connecting to the second device via multi-hop relay, and receive a response message for the discovery message. The discovery message may include a first timestamp and a first time budget, the value of which may be determined based on the QoS associated with the message to be sent to the second device via multi-hop relay.

[0279] 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.

[0280] 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.

[0281] 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.

[0282] 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 control 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 control 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.

[0283] Examples of wireless devices using this disclosure

[0284] Figure 24 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 25 ).

[0285] Reference Figure 24 Wireless devices 100 and 200 can correspond to Figure 23The 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 23 One or more processors 102 and 202 and / or one or more memories 104 and 204. For example, transceiver 114 may include Figure 23 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.

[0286] 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 22 100a), vehicles ( Figure 22 100b-1 and 100b-2), XR device ( Figure 22 100c), handheld device ( Figure 22 100d), home appliances ( Figure 22 100e), IoT devices ( Figure 22 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 22 400), BS ( Figure 22 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.

[0287] exist Figure 24In 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.

[0288] Examples of vehicles or autonomous vehicles using this disclosure

[0289] Figure 25 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.

[0290] Reference Figure 25 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 24 Blocks 110 / 130 / 140.

[0291] 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, depth 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.

[0292] 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.

[0293] 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.

[0294] 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.

[0295] 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, eNode B (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).

[0296] The embodiments of this disclosure can be implemented in various ways, such as hardware, firmware, software, or a combination thereof. When implemented in hardware, the embodiments of this disclosure can be implemented by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), processors, controllers, microcontrollers, or microprocessors.

[0297] When implemented in firmware or software, the various embodiments of this disclosure can be implemented in the form of modules, processes, functions, etc., that perform the above-described functions or operations. Software code can be stored in a storage unit and executed by a processor. The storage unit can be located inside or outside the processor and can exchange data with the processor through various known methods.

[0298] It will be apparent to those skilled in the art that this disclosure may be implemented in other specific forms without departing from its characteristics. Therefore, the detailed description above should not be construed as restrictive in all respects, but rather as exemplary. The scope of this disclosure should be determined by a reasonable interpretation of the appended claims, and all modifications falling within the equivalent scope of this disclosure should be included within its scope.

[0299] Industrial applicability

[0300] The embodiments described above are applicable to various mobile communication systems.

Claims

1. A method for forwarding discovery messages by a relay user equipment (UE) in a wireless communication system, the method comprising the steps of: Receive the first discovery message for multi-hop relay; as well as Based on the first timestamp and time budget included in the first message, determine whether to forward the first discovery message.

2. The method according to claim 1, wherein, Based on the remaining time budget being greater than a specific threshold, the relay UE forwards the first discovery message, whereby the remaining time budget is the time budget minus the difference between the first timestamp and the second timestamp.

3. The method according to claim 1, wherein, If the remaining time budget is equal to or less than a certain threshold, the relay UE will not forward the first discovery message. The remaining time budget is the time budget minus the difference between the first timestamp and the second timestamp.

4. The method according to claim 1, wherein, The initial value of the time budget is determined based on the Quality of Service (QoS) associated with the messages to be sent between the first and second devices via the multi-hop relay connection.

5. The method according to claim 2, wherein, After the relay UE replaces the first timestamp with the second timestamp and the time budget with the remaining time budget, it forwards the first discovery message.

6. The method according to claim 2, wherein, The first discovery message also includes a first sequence number.

7. The method according to claim 6, further comprising, after forwarding the first discovery message, receiving a second discovery message including a second sequence number. in, Since the source device and the target device are identical between the first discovery message and the second discovery message, and the second sequence number is the same as the first sequence number, the second discovery message is not forwarded.

8. The method according to claim 2, wherein, The first discovery message also includes information about the first hop count.

9. The method of claim 8, further comprising, after forwarding the first discovery message, receiving a second discovery message including a second hop count. in, The second discovery message is not forwarded because the source device and the target device are identical between the first discovery message and the second discovery message, and the second hop count is greater than the first hop count.

10. The method according to claim 1, wherein, The multi-hop relay is a user equipment-to-network (U2N) relay used to send and receive data between a remote UE and the network.

11. A computer-readable recording medium having a program recorded thereon for performing the method according to claim 1.

12. A relay user equipment (UE) for forwarding discovery messages in a wireless communication system, the relay UE comprising: Radio frequency (RF) transceivers; as well as The processor is connected to the RF transceiver. The processor controls the RF transceiver to receive a first discovery message for multi-hop relay, and determines whether to forward the first discovery message based on the first timestamp and time budget included in the first message.

13. A processing apparatus for controlling the forwarding of discovery messages in a wireless communication system by a 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 that, when executed by the at least one processor, cause the relay UE to: Receive the first discovery message for multi-hop relay; and Based on the first timestamp and time budget included in the first message, determine whether to forward the first discovery message.

14. A method for transmitting a discovery message by a first device in a wireless communication system, the method comprising the steps of: Send a discovery message for connecting to the second device via multi-hop relay; as well as Receive a response message in response to the discovery message. The discovery message includes a first timestamp and a time budget, and the value of the time budget is determined based on the Quality of Service (QoS) associated with the message to be sent to the second device via the multi-hop relay.

15. A first means for transmitting a discovery message in a wireless communication system, the first means comprising: Radio frequency (RF) transceivers; as well as The processor is connected to the RF transceiver. The processor controls the RF transceiver to send a discovery message for connecting to the second device via multi-hop relay, and receives a response message for the discovery message. The discovery message includes a first timestamp and a first time budget, and the value of the first time budget is determined based on the Quality of Service (QoS) associated with the message to be sent to the second device via the multi-hop relay.

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