METHOD FOR OPERATING A RELAY UE WHEN RECEIVING RRC REJECTION IN A WIRELESS COMMUNICATION SYSTEM - Patent application

Abstract

One embodiment of the present invention is a method for operating a relay UE in a wireless communication system, the method including: the relay UE establishing a PC5 unicast link with a remote UE; the relay UE sending an RRC setup request to a first base station; the relay UE receiving an RRC rejection message from the first base station, the RRC rejection message including a first waiting time; and, based on receiving the RRC rejection message, the relay UE sending a first notification message to the remote UE; the first notification message including a second waiting time based on the first waiting time received by the relay UE from the first base station.

Description

[Technical field]

[0001] The following description relates to wireless communication systems, and more particularly to an operating method and apparatus for a relay UE that receives an RRC reject or an RRC release. [Background technology]

[0002] Wireless access systems have been widely deployed to provide various communication services such as voice and data. Generally, wireless communication systems are multiple access systems that can 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, etc.

[0003] Wireless communication systems use various RATs (Radio Access Technologies) such as LTE, LTE-A, and WiFi, including 5G. The three main areas of requirements for 5G include (1) the Enhanced Mobile Broadband (eMBB) area, (2) the massive Machine Type Communication (mMTC) area, and (3) the Ultra-Reliable and Low Latency Communications (URLLC) area. Some use cases require multiple areas for optimization, while other use cases can focus on only one Key Performance Indicator (KPI). 5G is to support such various use cases in a flexible and reliable manner.

[0004] eMBB goes beyond basic mobile Internet access to cover rich two-way work, media and entertainment applications in the cloud or augmented reality. Data is one of the core drivers of 5G, and for the first time in the 5G era, dedicated voice services may not be seen. In 5G, voice is expected to be handled simply as an application using the data connectivity provided by the communication system. The main causes for the increased traffic volume are the increasing size of content and the growing number of applications that require high data transmission rates. Streaming services (audio and video), conversational video and mobile Internet connections will be widely used as more devices are connected to the Internet. Such many applications require always-on connectivity to push real-time information and notifications to users. Cloud storage and applications are proliferating on mobile communication platforms, which can be applied to both business and entertainment. Cloud storage is also a particular use case that will drive the growth of uplink data transmission rates. 5G will also be used for remote work in the cloud, which requires very low end-to-end latency to maintain a good user experience when haptic interfaces are used. Entertainment, e.g., cloud gaming and video streaming, are other key factors that increase the demand for mobile broadband capabilities. Entertainment is essential on smartphones and tablets everywhere, including in high-mobility environments such as trains, cars, and airplanes. Further use cases include augmented reality and information retrieval for entertainment, where augmented reality requires very low latency and instantaneous data volume.

[0005] One of the most anticipated use cases for 5G is its ability to seamlessly connect embedded sensors across all industries, i.e. mMTC. It is predicted that there will be 20.4 billion potential IoT devices by 2020. Industrial IoT is one area where 5G will play a key role in enabling smart cities, asset tracking, smart utility, agriculture and security infrastructure.

[0006] URLLC includes new services that will transform industries with ultra-reliable / available low-latency links such as remote control of key infrastructure and self-driving vehicles. Reliability and latency levels are essential for smart grid control, industrial automation, robotics, and drone control and coordination.

[0007] A number of use cases will now be described in more detail.

[0008] 5G is a means of delivering streams rated at hundreds of megabytes per second to gigabytes per second, and can complement fiber-to-the-home (FTTH) and cable-based broadband (or DOCSIS). Such high speeds are required for virtual and augmented reality, as well as for delivering TV at resolutions of 4K and above (6K, 8K and beyond). Virtual reality (VR) and augmented reality (AR) applications include nearly immersive sports competitions. Certain applications may require special network configurations. For example, VR games require integration between the core servers and the network operator's edge network servers, in order for gaming companies to minimize latency.

[0009] Automotive is expected to be an important new driver for 5G with many use cases for mobile communications to vehicles. For example, entertainment for passengers requires high concurrency and high mobility mobile broadband because future users expect high quality connectivity regardless of their location and speed. Another use case in the automotive field is the augmented reality dashboard, which displays information overlaid on the front window where the driver is looking, identifying objects in the dark and informing the driver of the object's distance and movement. Future wireless modules will enable vehicle-to-vehicle communication, information exchange between vehicles and supporting infrastructure, and between automobiles and other connected devices (e.g., devices accompanied by pedestrians). Safety systems can reduce the risk of accidents by guiding the driver to alternative courses of action for safer driving. The next step will be remote piloting, or self-driven vehicles. This will require very reliable and very fast communication between different self-driving vehicles and between automobiles and infrastructure. In the future, self-driving vehicles will perform all driving activities and the driver will only focus on traffic anomalies that the vehicle itself cannot identify. The technical requirements of autonomous vehicles demand ultra-low latency and ultra-fast reliability to increase traffic safety to levels unattainable by humans.

[0010] Smart cities and smart homes, also referred to as smart society, are embedded with dense wireless sensor networks. A distributed network of intelligent sensors identifies requirements for cost and energy efficient maintenance of the city or home. A similar setup is made for each home. Temperature sensors, window and heating controls, burglar alarms and home appliances are all wirelessly linked. Most of such sensors are typically low data transmission rates, low power and low cost. However, real-time HD video, for example, is required for certain types of devices for surveillance.

[0011] The consumption and distribution of energy, including heat or gas, is highly decentralized, requiring automated control of distributed sensor networks. A smart grid interconnects such sensors using digital information and communication technologies to collect and act upon information. This information includes supplier and consumer behavior, allowing the smart grid to improve the efficiency, reliability, economy, production sustainability, and distribution of fuels, such as electricity, in an automated manner. A smart grid can be viewed as another sensor network with low latency.

[0012] In the health sector, there are many applications that benefit from mobile communications. Communications systems support telemedicine, providing clinical care over long distances. This overcomes the barrier of distance and improves access to medical services that are not consistently available in remote rural areas. It can also be used to save lives in critical care and emergency situations. Mobile-based wireless sensor networks can provide remote monitoring and sensing of parameters such as heart rate and blood pressure.

[0013] Wireless and mobile communications are becoming important in industrial applications. Wiring is expensive to install and maintain. Therefore, the possibility of replacing cables with wireless links, reconfiguring them, is an attractive opportunity for many industrial sectors. However, achieving this requires that wireless links perform with cable-like latency, reliability and capacity, and that they are easy to manage. Low latency and very low error rates are new requirements that need to be coupled with 5G.

[0014] Logistics and freight tracking are important use cases for mobile communications using location-based information systems to enable ubiquitous inventory and package tracking. Logistics and freight tracking use cases typically require low data rates, but require wide range and reliable location information.

[0015] A wireless communication system is a multiple access system that supports communication with multiple users by sharing available system resources (e.g., bandwidth, transmission power, etc.) Examples of multiple access systems include code division multiple access (CDMA) systems, frequency division multiple access (FDMA) systems, time division multiple access (TDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, and multi carrier frequency division multiple access (MC-FDMA) systems.

[0016] Sidelink (SL) is a communication method that sets up a direct link between terminals (User Equipment, UE) to directly transmit voice or data between terminals without going through a base station (BS). SL is one solution to alleviate the burden on base stations due to the rapidly increasing data traffic.

[0017] V2X (vehicle-to-everything) refers to a communication technology that exchanges information with other vehicles, pedestrians, infrastructure, etc. through wired and wireless communication. V2X is divided into four types: V2V (vehicle-to-vehicle), V2I (vehicle-to-infrastructure), V2N (vehicle-to-network), and V2P (vehicle-to-pedestrian). V2X communication is provided by the PC5 interface and / or Uu interface.

[0018] Meanwhile, as more communication devices require larger communication capacity, the need for improved mobile broadband communication compared to existing radio access technologies (RATs) is emerging. As a result, communication systems that take into account reliability and latency-sensitive services or terminals are being discussed. The next-generation wireless access technology that takes into account such improved mobile broadband communication, massive MTC, and URLLC (Ultra-Reliable and Low Latency Communication) is called new radio access technology (RAT) or new radio (NR). NR can also support vehicle-to-everything (V2X) communication.

[0019] Figure 1 is a diagram explaining a comparison between V2X communication based on RATs prior to NR and V2X communication based on NR.

[0020] In relation to V2X communication, methods for providing safety services based on V2X messages such as Basic Safety Message (BSM), Cooperative Awareness Message (CAM), and Decentralized Environmental Notification Message (DENM) have been discussed in RATs prior to NR. V2X messages include location information, dynamic information, attribute information, etc. For example, a terminal can transmit a periodic message type CAM and / or an event triggered message type DENM to other terminals.

[0021] For example, the CAM includes vehicle dynamic state information such as direction and speed, vehicle static data such as dimensions, exterior lighting conditions, route details, and other basic vehicle information. For example, a terminal may broadcast a CAM, and the delay of the CAM is less than 100 ms. For example, in the event of an emergency situation such as a vehicle breakdown or accident, the terminal may generate and transmit a DENM to other terminals. For example, all vehicles within the transmission range of the terminal may receive the CAM and / or the DENM. In this case, the DENM has a higher priority than the CAM.

[0022] Subsequently, various V2X scenarios related to V2X communication are defined in NR, for example, various V2X scenarios include vehicle platooning, enhanced driving, extended sensors, remote driving, etc.

[0023] For example, based on platooning vehicles, vehicles dynamically form groups and move together. For example, to perform platooning operations based on platooning vehicles, the vehicles in the group receive periodic data from a leading vehicle. For example, the vehicles in the group can use the periodic data to reduce or increase the spacing between the vehicles.

[0024] For example, based on the enhanced driving, the vehicles can be semi-automated or fully automated. Each vehicle can adjust its trajectories or maneuvers based on data obtained from local sensors of nearby vehicles and / or nearby logical entities. For example, each vehicle can share driving intentions with nearby vehicles.

[0025] For example, based on the extended sensor, raw data, processed data, or live video data obtained by local sensors can be exchanged between vehicles, logic elements, pedestrian terminals, and / or V2X application servers. Thus, for example, a vehicle can recognize an environment that is improved over the environment that can be sensed using its own sensors.

[0026] For example, based on remote driving, a remote driver or a V2X application can operate or control a remote vehicle for a person who cannot drive or for a remote vehicle located in a dangerous environment. For example, when a route is predictable, such as in public transportation, cloud computing-based driving is used to operate or control a remote vehicle. For example, a connection to a cloud-based back-end service platform is considered for remote driving.

[0027] Meanwhile, methods to specify service requirements for various V2X scenarios such as platooning vehicles, improved driving, extended sensors, and remote driving are being discussed for V2X communication based on NR. Summary of the Invention [Problem to be solved by the invention]

[0028] The technical problem of the present disclosure is how to notify a remote UE of an RRCRelease or RRCReject message received from a network and transmit the cause value of the notification together with a wait time. [Means for solving the problem]

[0029] One embodiment is a method for operating a relay UE in a wireless communication system, the method including: the relay UE establishing a PC5 unicast link with a remote UE; the relay UE sending an RRC setup request to a first base station; the relay UE receiving an RRC reject message from the first base station including a first waiting time; and based on receiving the RRC reject message, the relay UE sending a first notification message to the remote UE, the first notification message including a second waiting time based on the first waiting time received by the relay UE from the first base station.

[0030] One embodiment is a relay UE device in a wireless communication system, comprising at least one processor and at least one computer memory operatively connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations, the operations including establishing a PC5 unicast link with a remote UE, sending an RRC setup request to a first base station, receiving an RRC reject message from the first base station including a first waitTime, and sending a first notification message to the remote UE based on receiving the RRC reject message, the first notification message including a second waitTime based on the first waitTime received by the relay UE from the first base station.

[0031] The relay UE receives a request related to the release of the PC5 unicast link from the remote UE after the second waiting time expires.

[0032] The request related to the release of the PC5 unicast link is sent by the remote UE after a time in which a predetermined offset is applied to the waiting time has elapsed.

[0033] The request to release the PC5 unicast link is received by an RRCReconfigurationSidelink message.

[0034] The second waiting time is related to the remote UE's decision to release the PC5 unicast link.

[0035] The first notification message is transmitted after the first waiting time has elapsed.

[0036] The relay UE establishes an RRC connection with a second base station after the first waiting time has elapsed.

[0037] The relay UE sends a PC5 RRC message to the remote UE notifying the release based on receiving a release message from the second base station.

[0038] After receiving the PC5 RRC message, the relay UE sends a second notification to the remote UE based on receiving a message other than an RRCReestablishmentRequest, an RRCResumeRequest, and an RRCSetupRequest from the relay UE.

[0039] The relay UE sends a third notification to the remote UE based on the failure of the message delivery of the remote UE to the second base station, notifying the remote UE of the failure.

[0040] The message corresponds to an RRC message.

[0041] The message is a response to the RRC Release message, that is, an RLC ACK message. Effect of the Invention

[0042] According to one embodiment, the remote UE can efficiently determine how long to maintain the SL connection based on the waitTime. Also, when the cell of the relay UE changes during path switching of the remote UE, the operation of the relay UE and the remote UE is defined, thereby eliminating uncertainty in the operation of the relay UE and the remote UE. [Brief description of the drawings]

[0043] The drawings accompanying this specification are provided to aid in the understanding of the embodiments, illustrate various embodiments, and together with the description serve to explain the principles.

[0044] [Figure 1] FIG. 1 is a diagram for explaining a comparison between V2X communication based on a RAT prior to NR and V2X communication based on NR. [Diagram 2] FIG. 1 illustrates a structure of an LTE system according to one embodiment of the present disclosure. [Diagram 3] FIG. 1 illustrates a radio protocol architecture for the user plane and control plane according to one embodiment of the present disclosure. [Figure 4] FIG. 1 illustrates a structure of an NR system according to one embodiment of the present disclosure. [Diagram 5] FIG. 1 illustrates a functional division between NG-RAN and 5GC according to one embodiment of the present disclosure. [Figure 6] FIG. 1 is a diagram illustrating a structure of an NR radio frame to which an embodiment can be applied. [Figure 7] A diagram illustrating a slot structure of an NR frame according to one embodiment of this disclosure. [Figure 8] FIG. 1 illustrates a radio protocol architecture for SL communication according to one embodiment of the present disclosure. [Figure 9]FIG. 1 illustrates a radio protocol architecture for SL communication according to one embodiment of the present disclosure. [Figure 10] FIG. 1 illustrates a V2X synchronization source or synchronization reference according to one embodiment of the present disclosure. [Figure 11] FIG. 13 is a diagram showing a procedure in which a terminal performs V2X or SL communication depending on a transmission mode according to one embodiment of the present disclosure. [Figure 12] FIG. 2 is a diagram showing a procedure by which a terminal performs path switching according to one embodiment of the present disclosure. [Figure 13] FIG. 2 is a diagram illustrating switching from a direct path to an indirect path. [Figure 14] FIG. 1 is a diagram for explaining UE-to-UE relay selection. [Figure 15] FIG. 1 is a diagram for explaining UE-to-UE relay selection. [Figure 16] FIG. 1 is a diagram for explaining an embodiment. [Figure 17] 1A to 1C are diagrams illustrating various devices to which the embodiment can be applied. [Figure 18] 1A to 1C are diagrams illustrating various devices to which the embodiment can be applied. [Figure 19] 1A to 1C are diagrams illustrating various devices to which the embodiment can be applied. [Figure 20] 1A to 1C are diagrams illustrating various devices to which the embodiment can be applied. [Figure 21] 1A to 1C are diagrams illustrating various devices to which the embodiment can be applied. [Figure 22] 1A to 1C are diagrams illustrating various devices to which the embodiment can be applied. [Figure 23] 1A to 1C are diagrams illustrating various devices to which the embodiment can be applied. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045] In various embodiments of the present invention, " / " and "," indicate "and / or." For example, "A / B" means "A and / or B." Also, "A, B" means "A and / or B." "A / B / C" means "any one of A, B, and / or C." Also, "A, B, C" means "any one of A, B, and / or C."

[0046] In various embodiments of the present invention, "or" denotes "and / or." For example, "A or B" includes "A only," "B only," and / or "both A and B." In other words, "or" can be interpreted as "additionally or alternatively."

[0047] The following technologies can be used for various wireless 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), Single Carrier Frequency Division Multiple Access (SC-FDMA), etc. CDMA can be realized by radio technologies such as Universal Terrestrial Radio Access (UTRA) and CDMA2000. TDMA can be realized by radio technologies such as Global System for Mobile communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE). OFDMA can be realized by radio technologies such as IEEE802.11 (Wi-Fi), IEEE802.16 (WiMAX), IEEE802-20, Evolved UTRA (E-UTRA), etc. IEEE 802.16m is an evolution of IEEE 802.16e and provides backward compatibility with systems based on IEEE 802.16e. UTRA is part of the Universal Mobile Telecommunications System (UMTS). 3GPP (registered trademark) 3rd Generation Partnership Project (LTE) long term evolution (LTE) is part of Evolved UMTS (E-UMTS) that uses E-UTRA and employs OFDMA on the downlink and SC-FDMA on the uplink. LTE-A (Advanced) is an evolution of 3GPP LTE.

[0048] 5G NR is the technology that follows LTE-A and is a new clean-slate mobile communication system with characteristics such as high performance, low latency, and high availability. 5G NR can utilize all available spectrum resources, including low-frequency bands below 1 GHz, intermediate-frequency bands from 1 GHz to 10 GHz, and high-frequency (millimeter wave) bands above 24 GHz.

[0049] For a clearer description, the following description will focus on LTE-A or 5G NR, but the technical idea according to an embodiment of the present invention is not limited thereto.

[0050] 2 shows the structure of an LTE system according to one embodiment of the present invention, which is also called E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) or LTE (Long Term Evolution) / LTE-A system.

[0051] 2, the E-UTRAN includes a base station 20 that provides a control plane and a user plane to a terminal 10. The terminal 10 may be fixed or mobile, and may also be referred to by terms such as mobile station (MS), user terminal (UT), subscriber station (SS), mobile terminal (MT), wireless device, etc. In general, the base station 20 is a fixed station that communicates with the terminal 10, and may also be referred to by terms such as evolved NodE-B (eNB), base transceiver system (BTS), access point (AP), etc.

[0052] The base stations 20 are connected to each other via an X2 interface. The base stations 20 are connected to an evolved packet core (EPC, 30) via an S1 interface, more specifically to a mobility management entity (MME) via an S1-MME, and to a serving gateway (S-GW) via an S1-U.

[0053] EPC30 is composed of MME, S-GW and P-GW (Packet data network-gateway). MME has terminal connection information and terminal capability information, and such information is mainly used for terminal mobility management. S-GW is a gateway with E-UTRAN as an end point, and P-GW is a gateway with PDN (Packet Data Network) as an end point.

[0054] The radio interface protocol layers between a terminal and a network are classified into Layer 1 (L1), Layer 2 (L2), and Layer 3 (L3) based on the bottom three layers of the Open System Interconnection (OSI) reference model known in communication systems. Among them, the physical layer belonging to Layer 1 provides information transmission services using physical channels, and the Radio Resource Control (RRC) layer belonging to Layer 3 controls radio resources between a terminal and a network. To this end, the RRC layer exchanges RRC messages between a terminal and a base station.

[0055] FIG. 3(a) illustrates a radio protocol architecture for the user plane according to one embodiment of the present invention.

[0056] 3(b) shows a radio protocol architecture for the control plane according to one embodiment of the present invention. The user plane is a protocol stack for user data transmission, and the control plane is a protocol stack for transmission of control signals.

[0057] Referring to Figures 3(a) and A3, the physical layer provides information transmission services to higher layers using physical channels. The physical layer is connected to the higher layer, the Medium Access Control (MAC) layer, via transport channels. Data moves between the MAC layer and the physical layer via the transport channels. The transport channels are classified according to how and with what characteristics data is transmitted over the radio interface.

[0058] Data is transferred between different physical layers, i.e., between the physical layers of a transmitter and a receiver, through a physical channel. The physical channel is modulated by the Orthogonal Frequency Division Multiplexing (OFDM) method and uses time and frequency as radio resources.

[0059] The MAC layer provides services to the higher-level RLC (radio link control) layer via logical channels. The MAC layer provides a mapping function from multiple logical channels to multiple transmission channels. The MAC layer also provides a logical channel multiplexing function by mapping multiple logical channels to a single transmission channel. The MAC layer provides data transmission services on the logical channels.

[0060] The RLC layer performs concatenation, segmentation, and reassembly of RLC SDUs (Serving Data Units). To guarantee various Quality of Service (QoS) required by Radio Bearers (RBs), the RLC layer provides three operation modes: Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM). AM RLC provides error correction through automatic repeat request (ARQ).

[0061] The Radio Resource Control (RRC) layer is defined only in the control plane. The RRC layer is responsible for controlling logical channels, transmission channels, and physical channels in relation to the configuration, reconfiguration, and release of radio bearers. RB refers to a logical path provided by the first layer (physical layer or PHY layer) and the second layer (MAC layer, RLC layer, and PDCP (Packet Data Convergence Protocol) layer) for data transmission between the terminal and the network.

[0062] The functions of the PDCP layer in the user plane include transmission of user data, header compression, and ciphering, and the functions of the PDCP layer in the control plane include transmission of control plane data and encryption / integrity protection.

[0063] RB configuration refers to the process of defining the characteristics of the radio protocol layer and channel to provide a specific service and setting each specific parameter and operation method. RB is again divided into two types, SRB (Signaling Radio Bearer) and DRB (Data Radio Bearer). SRB is used as a path to transmit RRC messages in the control plane, and DRB is used as a path to transmit user data in the user plane.

[0064] If an RRC connection is established between the RRC layer of the terminal and the RRC layer of the E-UTRAN, the terminal enters the RRC_CONNECTED state, otherwise it enters the RRC_IDLE state. In the case of NR, the RRC_INACTIVE state is further defined, and a terminal in the RRC_INACTIVE state can release its connection to the base station while maintaining its connection to the core network.

[0065] Downlink transmission channels for transmitting data to terminals in a network include a Broadcast Channel (BCH) for transmitting system information and a Shared Channel (SCH) for transmitting user traffic and control messages. Traffic or control messages of downlink multicast or block services are transmitted via the downlink SCH or via a separate Multicast Channel (MCH). On the other hand, uplink transmission channels for transmitting data from terminals to a network include a Random Access Channel (RACH) for transmitting initial control messages and a Shared Channel (SCH) for transmitting user traffic and control messages.

[0066] Logical channels that are above transmission channels and are mapped to transmission channels include BCCH (Broadcast Control Channel), PCCH (Paging Control Channel), CCCH (Common Control Channel), MCCH (Multicast Control Channel), MTCH (Multicast Traffic Channel), etc.

[0067] A physical channel consists of multiple OFDM symbols in the time domain and multiple subcarriers in the frequency domain. One subframe consists of multiple OFDM symbols in the time domain. A resource block is a resource allocation unit, consisting of multiple OFDM symbols and multiple subcarriers. In addition, each subframe can use a specific subcarrier of a specific OFDM symbol (e.g., the first OFDM symbol) of the subframe for PDCCH (Physical Downlink Control Channel), i.e., L1 / L2 control channel. TTI (Transmission Time Interval) is the unit time of subframe transmission.

[0068] FIG. 4 shows the structure of an NR system according to one embodiment of the present invention.

[0069] Referring to FIG. 4, a Next Generation-Radio Access Network (NG-RAN) includes a next generation-Node BF cell (gNB) and / or an eNB that provides user plane and control plane protocol termination to a terminal. FIG. 4 illustrates a case where only a gNB is included. The gNB and the eNB are connected to each other via an Xn interface. The gNB and the eNB are connected to a 5th generation core network (5G Core Network: 5GC) via an NG interface. More specifically, the gNB and the eNB are connected to an access and mobility management function (AMF) via an NG-C interface, and to a user plane function (UPF) via an NG-U interface.

[0070] FIG. 5 shows the functional division between NG-RAN and 5GC according to one embodiment of the present invention.

[0071] Referring to Figure 5, the gNB provides functions such as Inter Cell RRM, Radio Bearer Management (RB control), Connection Mobility Control, Radio Admission Control, Measurement configuration & Provision, and dynamic resource allocation. The AMF provides functions such as NAS (Non Access Stratum) security and idle state mobility handling. The UPF provides functions such as Mobility Anchoring and PDU (Protocol Data Unit) processing. The SMF (Session Management Function) provides functions such as terminal IP (Internet Protocol) address allocation and PDU section control.

[0072] FIG. 6 shows a structure of an NR radio frame to which an embodiment of the present invention can be applied.

[0073] Referring to Figure 6, in NR, radio frames are used for uplink and downlink transmission. A radio frame has a length of 10 ms and is defined by two 5 ms half-frames (HF). A half-frame includes five 1 ms subframes (SF). A subframe is divided into one or more slots, and the number of slots in a subframe depends on the subcarrier spacing (SCS). Each slot includes 12 or 14 OFDM(A) symbols depending on the cyclic prefix (CP).

[0074] When the nominal CP is used, each slot contains 14 symbols. When the extended CP is used, each slot contains 12 symbols, where the symbols include OFDM symbols (or CP-OFDM symbols), SC-FDMA symbols (or DFT-s-OFDM symbols).

[0075] Table 1 shows the number of symbols per slot (N slot symbol ), the number of slots per frame (N frame,u slot ) and the number of slots per subframe (N subframe,u slot ) is shown below.

[0076] [Table 1]

[0077] Table 2 illustrates the number of symbols per slot, the number of slots per frame, and the number of slots per subframe according to the SCS when the extended CP is used.

[0078] [Table 2]

[0079] In the NR system, OFDM neurology (e.g., SCS, CP length, etc.) can be set to be different between multiple cells merged into one terminal, and thus the (absolute time) duration of time resources (e.g., subframes, slots, or TTIs) (commonly referred to as TUs (Time Units) for convenience) consisting of the same number of symbols is set to be different between the merged cells.

[0080] In NR, multiple neurologies or SCSs are supported to support various 5G services. For example, when the SCS is 15 kHz, wide areas in traditional cellular bands are supported, and when the SCS is 30 kHz / 60 kHz, dense urban areas, lower latency, and wider carrier bandwidth are supported. When the SCS is 60 kHz or higher, bandwidths larger than 24.25 GHz are supported to overcome phase noise.

[0081] The NR frequency band is defined by two types of frequency ranges. The two types of frequency ranges are FR1 and FR2. The values ​​of the frequency ranges can be changed, and for example, the two types of frequency ranges are as shown in Table 3 below. Among the frequency ranges used in the NR system, FR1 means "sub 6GHz range" and FR2 means "above 6GHz range", and are also called millimeter wave (mmW).

[0082] [Table 3]

[0083] As described above, the numerical value of the frequency range of the NR system can be changed. For example, FR1 includes a band from 410 MHz to 7125 MHz as shown in Table 4 below. That is, FR1 includes a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or higher. For example, the frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or higher included in FR1 includes an unlicensed band. The unlicensed band is used for various purposes, for example, for communication for vehicles (e.g., autonomous driving).

[0084] [Table 4]

[0085] FIG. 7 is a diagram showing a slot structure of an NR frame according to one embodiment of the present invention.

[0086] 7, a slot includes a number of symbols in the time domain. For example, in the case of the general CP, one slot includes 14 symbols, whereas in the case of the extended CP, one slot includes 12 symbols. Alternatively, in the case of the general CP, one slot includes 7 symbols, whereas in the case of the extended CP, one slot includes 6 symbols.

[0087] A carrier includes multiple subcarriers in the frequency domain. An RB (Resource Block) is defined as multiple (e.g., 12) consecutive subcarriers in the frequency domain. A BWP is defined as multiple consecutive PRBs (Physical RBs) in the frequency domain and corresponds to one numerology (e.g., SCS, CP length, etc.). A carrier includes up to N (e.g., 5) BWPs. Data communication is performed in the activated BWPs. Each element is called a Resource Element (RE) in the resource grid, and one complex symbol can be mapped to it.

[0088] Meanwhile, a radio interface between terminals or between a terminal and a network is composed of an L1 layer, an L2 layer, and an L3 layer. In various embodiments of the present invention, the L1 layer refers to a physical layer. The L2 layer refers to, for example, any one of a MAC layer, an RLC layer, a PDCP layer, and an SDAP layer. The L3 layer refers to, for example, an RRC layer.

[0089] Below, we will explain V2X or SL (sidelink) communication.

[0090] Figure 8 illustrates a radio protocol architecture for SL communication according to one embodiment of the present invention. More specifically, Figure 8(a) illustrates the LTE user plane protocol stack, and Figure 8(b) illustrates the LTE control plane protocol stack.

[0091] 9 shows a radio protocol architecture for SL communication according to one embodiment of the present invention. More specifically, FIG. 9(a) shows the NR user plane protocol stack, and FIG. 9(b) shows the NR control plane protocol stack.

[0092] FIG. 10 illustrates a V2X synchronization source or synchronization reference according to one embodiment of the present invention.

[0093] Referring to Figure 10, in V2X, a terminal is directly synchronized to a global navigation satellite system (GNSS) or indirectly synchronized to a GNSS by a terminal (in or out of network coverage) that is directly synchronized to the GNSS. When the GNSS is set as a synchronization source, the terminal calculates the DFN and subframe number using the Coordinated Universal Time (UTC) and a (pre-)set DFN (Direct Frame Number) offset.

[0094] Alternatively, the terminal is directly synchronized to the base station or is synchronized to another terminal time / frequency synchronized to the base station. For example, the base station is an eNB or a gNB. For example, when the terminal is within the network coverage, the terminal receives synchronization information provided by the base station and is directly synchronized to the base station. The terminal then provides synchronization information to other neighboring terminals. If the base station timing is set as the synchronization reference, the terminal follows the cell (if it is within the cell coverage in frequency), the primary cell or the serving cell (if it is outside the cell coverage in frequency) associated with the frequency for synchronization and downlink measurement.

[0095] The base station (e.g., serving cell) provides synchronization settings for the carrier used for V2X or SL communication. In this case, the terminal follows the synchronization settings received from the base station. If the terminal does not detect any cell in the carrier used for V2X or SL communication and does not receive synchronization settings from the serving cell, the terminal follows the preset synchronization settings.

[0096] Alternatively, the terminal may be synchronized to another terminal for which synchronization information cannot be obtained directly or indirectly from a base station or GNSS. The synchronization source and preference may be preset in the terminal, or may be set by a control message provided by the base station.

[0097] The SL synchronization source is related to the synchronization priority. For example, the relationship between the synchronization source and the synchronization priority is defined as shown in Table 14 or Table 15. Table 5 or Table 6 is only an example, and the relationship between the synchronization source and the synchronization priority can be defined in various ways.

[0098] [Table 5]

[0099] [Table 6]

[0100] In Table 5 or Table 6, P0 means the highest priority, and P6 means the lowest priority. In Table 5 or Table 6, the base station includes at least one of a gNB or an eNB.

[0101] Whether GNSS-based or base station-based synchronization is used is configured (pre-configured). In single-carrier operation, the terminal derives its transmission timing from the available synchronization reference with the highest priority.

[0102] The SL synchronization signal (SLSS) and synchronization information will be described below.

[0103] The SLSS includes a PSSS (Primary Sidelink Synchronization Signal) and a SSSS (Secondary Sidelink Synchronization Signal) as SL-specific sequences. The PSSS is called an S-PSS (Sidelink Primary Synchronization Signal), and the SSSS is called an S-SSS (Sidelink Secondary Synchronization Signal). For example, length-127 M-sequences are used for the S-PSS, and length-127 Gold sequences are used for the S-SSS. For example, the terminal uses the S-PSS to perform initial signal detection and acquire synchronization. For example, the terminal uses the S-PSS and S-SSS to acquire detailed synchronization and detect a synchronization signal ID.

[0104] The PSBCH (Physical Sidelink Broadcast Channel) is a (broadcast) channel that transmits basic (system) information that a terminal should know first before transmitting and receiving an SL signal. For example, the basic information includes information about SLSS, duplex mode (DM), TDD UL / DL (Time Division Duplex Uplink / Downlink) configuration, information about the resource pool, application type related to SLSS, subframe offset, broadcast information, etc. For example, in order to evaluate the performance of PSBCH, in NR V2X, the payload size of PSBCH is 56 bits including 24-bit CRC.

[0105] The S-PSS, S-SSS and PSBCH are included in a block format (e.g., SL SS (Synchronization Signal) / PSBCH block, hereinafter referred to as S-SSB (Sidelink-Synchronization Signal Block)) that supports periodic transmission. The S-SSB has the same neurology (i.e., SCS and CP length) as the PSCCH (Physical Sidelink Control Channel) / PSSCH (Physical Sidelink Shared Channel) in the carrier, and the transmission bandwidth is within the (pre-) set SL BWP (Sidelink BWP). For example, the bandwidth of the S-SSB is 11 RBs (Resource Blocks). For example, the PSBCH spans 11 RBs. In addition, the frequency location of the S-SSB is (pre-) set. Therefore, the terminal does not need to perform hypothesis detection in frequency to find the S-SSB in the carrier.

[0106] Meanwhile, in the NR SL system, multiple neurologies having different SCS and / or CP lengths are supported. At this time, as the SCS increases, the length of the time resource for the transmitting terminal to transmit the S-SSB becomes shorter. This reduces the coverage of the S-SSB. Therefore, in order to ensure the coverage of the S-SSB, the transmitting terminal transmits one or more S-SSBs to the receiving terminal within one S-SSB transmission period according to the SCS. For example, the number of S-SSBs that the transmitting terminal transmits to the receiving terminal within one S-SSB transmission period is pre-configured or configured in the transmitting terminal. For example, the S-SSB transmission period is 160 ms. For example, an S-SSB transmission period of 160 ms is supported for all SCSs.

[0107] For example, if the SCS is 15 kHz in FR1, the transmitting terminal transmits one or two S-SSBs to the receiving terminal within one S-SSB transmission period. For example, if the SCS is 30 kHz in FR1, the transmitting terminal transmits one or two S-SSBs to the receiving terminal within one S-SSB transmission period. For example, if the SCS is 60 kHz in FR1, the transmitting terminal transmits one, two, or four S-SSBs to the receiving terminal within one S-SSB transmission period.

[0108] FIG. 11 illustrates a procedure in which a terminal performs V2X or SL communication according to a transmission mode according to an embodiment of the present invention. The embodiment of FIG. 11 may be combined with various embodiments of the present disclosure. In various embodiments of the present invention, the transmission mode is also referred to as a mode or a resource allocation mode. Hereinafter, for convenience of explanation, the transmission mode in LTE is also referred to as an LTE transmission mode, and the transmission mode in NR is also referred to as an NR resource allocation mode.

[0109] For example, Fig. 11(a) illustrates terminal operation related to LTE transmission mode 1 or LTE transmission mode 3. For example, Fig. 11(a) illustrates terminal operation related to NR resource allocation mode 1. For example, LTE transmission mode 1 can be applied to general SL communication, and LTE transmission mode 3 can be applied to V2X communication.

[0110] For example, FIG. 11(b) illustrates terminal operation associated with LTE transmission mode 2 or LTE transmission mode 4. Or, for example, FIG. 11(b) illustrates terminal operation associated with NR resource allocation mode 2.

[0111] 11(a), in LTE transmission mode 1, LTE transmission mode 3, or NR resource allocation mode 1, a base station schedules SL resources to be used by a terminal for SL transmission. For example, in step S8000, the base station transmits information related to SL resources and / or information related to UL resources to a first terminal. For example, the UL resources include PUCCH resources and / or PUSCH resources. For example, the UL resources are resources for reporting SL HARQ feedback to the base station.

[0112] For example, the first terminal receives information on dynamic grant (DG) resources and / or information on configured grant (CG) resources from the base station. For example, the CG resources include CG type 1 resources or CG type 2 resources. In this specification, the DG resources are resources that the base station configures / assigns to the first terminal via downlink control information (DCI). In this specification, the CG resources are (periodic) resources that the base station configures / assigns to the first terminal via DCI and / or RRC messages. For example, in the case of CG type 1 resources, the base station transmits an RRC message including information on the CG resources to the first terminal. For example, in the case of CG type 2 resources, the base station transmits an RRC message including information on the CG resources to the first terminal, and the base station transmits a DCI regarding activation or release of the CG resources to the first terminal.

[0113] In step S8010, the first terminal transmits a PSCCH (e.g., SCI (Sidelink Control Information) or 1st-stage SCI) to the second terminal based on resource scheduling. In step S8020, the first terminal transmits a PSSCH (e.g., 2nd-stage SCI, MAC PDU, data, etc.) related to the PSCCH to the second terminal. In step S8030, the first terminal receives a PSFCH related to the PSCCH / PSSCH from the second terminal. For example, HARQ feedback information (e.g., NACK information or ACK information) is received from the second terminal via the PSFCH. In step S8040, the first terminal transmits / reports the HARQ feedback information to the base station via the PUCCH or PUSCH. For example, the HARQ feedback information reported to the base station is information generated by the first terminal based on the HARQ feedback information received from the second terminal. For example, the HARQ feedback information reported to the base station is information generated by the first terminal based on a preset rule. For example, the DCI is a DCI for SL scheduling. For example, the format of the DCI is DCI format 3_0 or DCI format 3_1. Table 7 shows an example of DCI for SL scheduling.

[0114] [Table 7]

[0115] Referring to FIG. 11(b), in LTE transmission mode 2, LTE transmission mode 4, or NR resource allocation mode 2, the terminal determines the SL transmission resource within the SL resource set by the base station / network or the preset SL resource. For example, the set SL resource or the preset SL resource is a resource pool. For example, the terminal autonomously selects or schedules a resource for SL transmission. For example, the terminal selects a resource within the set resource pool and performs SL communication. For example, the terminal performs a sensing and resource (re)selection procedure and selects a resource within the selection window by itself. For example, this sensing is performed on a subchannel basis. For example, in step S8010, the first terminal that selects a resource within the resource pool by itself transmits a PSCCH (e.g., SCI (Sidelink Control Information) or 1st-stage SCI) to the second terminal using this resource. In step S8020, the first terminal transmits a PSSCH (e.g., 2nd-stage SCI, MAC PDU, data, etc.) related to the PSCCH to the second terminal. In step S8030, the first terminal receives a PSFCH related to the PSCCH / PSSCH from the second terminal.

[0116] 11(a) or (b), for example, the first terminal transmits an SCI to the second terminal on the PSCCH. Or, for example, the first terminal transmits two consecutive SCIs (e.g., 2-stage SCIs) to the second terminal on the PSCCH and / or PSSCH. In this case, the second terminal decodes the two consecutive SCIs (e.g., 2-stage SCIs) to receive the PSSCH from the first terminal. In this specification, the SCI transmitted on the PSCCH is referred to as the 1st SCI, the first SCI, the 1st-stage SCI, or the 1st-stage SCI format, and the SCI transmitted on the PSSCH is referred to as the 2nd SCI, the second SCI, the 2nd-stage SCI, or the 2nd-stage SCI format. For example, the 1st-stage SCI format includes SCI format 1-A, and the 2nd-stage SCI format includes SCI format 2-A and / or SCI format 2-B. Table 8 shows an example of the 1st-stage SCI format.

[0117] [Table 8]

[0118] Table 9 shows an example of the 2nd-stage SCI format.

[0119] [Table 9]

[0120] 11(a) or (b), in step S8030, the first terminal receives a PSFCH based on Table 10. For example, the first terminal and the second terminal determine a PSFCH resource based on Table 10, and the second terminal transmits HARQ feedback to the first terminal using the PSFCH resource.

[0121] [Table 10]

[0122] Referring to FIG. 11(a), in step S8040, the first terminal transmits SLHARQ feedback to the base station via PUCCH and / or PUSCH according to Table 11.

[0123] [Table 11]

[0124] Meanwhile, the following Table 12 is the content related to the selection and reselection of the sidelink relay UE disclosed in 3GPP TS 36.331. The content of Table 12 is used as the prior art of the present invention, and the necessary details related thereto are referred to 3GPP TS 36.331.

[0125] [Table 12]

[0126] Figure 12 shows the connection management and direct to indirect path switching process captured in the TR document (3GPP TR 38.836) for Rel-17 NR SL. The remote UE needs to establish its own PDU session / DRB with the network before transmitting user plane data.

[0127] The PC5 unicast link setup procedure of the PC5-RRC aspect of Rel-16 NR V2X is reused to set up a secure unicast link for L2 UE-to-Network relaying between the remote UE and the relay UE before the remote UE establishes a Uu RRC connection with the network via the relay UE.

[0128] For both in-coverage and out-of-coverage, when the remote UE initiates the first RRC message for connection setup with the gNB, the PC5 L2 configuration for transmission between the remote UE and the UE-to-Network Relay UE is based on the RLC / MAC configuration defined in the standard. The establishment of Uu SRB1 / SRB2 and DRB for the remote UE follows the procedure of legacy Uu configuration for L2 UE-to-Network Relay.

[0129] The higher level connection setup procedure shown in FIG. 12 is applied to the L2 UE-to-Network Relay.

[0130] In step S1200, the remote and relay UEs perform a discovery procedure and establish a PC5-RRC connection in step S1201 based on the conventional Rel-16 procedure.

[0131] In step S1202, the remote UE sends an initial RRC message (i.e., RRCSetupRequest) for connection setup with the gNB via the relay UE using the PC5 basic L2 configuration. The gNB responds with an RRC Setup message to the remote UE (S1203). The RRCSetup transmission to the remote UE uses the PC5 basic configuration. If the relay UE does not start from RRC_CONNECTED, it needs to perform its own connection setup when it receives a message for the PC5 basic L2 configuration. In this step, details for the relay UE to transmit the RRCSetupRequest / RRCSetup message to the remote UE are discussed in the WI step.

[0132] In step S1204, the gNB and the relay UE perform a relay channel setup procedure over Uu. Depending on the configuration of the gNB, the relay / remote UE sets up an RLC channel to relay SRB1 to the remote UE over PC5. This step prepares the relay channel for SRB1.

[0133] In step S1205, a remote UE SRB1 message (eg, an RRCSetupComplete message) is sent by PC5 to the gNB via the relay UE using the SRB1 relay channel, and the remote UE is RRC connected by Uu.

[0134] In step S1206, the remote UE and the gNB establish security according to legacy procedures, and the security message is conveyed via the relay UE.

[0135] In step S1210, the gNB sets up a further RLC channel between the gNB and the relay UE for traffic relay. Depending on the configuration of the gNB, the relay / remote UE sets up a further RLC channel between the remote UE and the relay UE for traffic relay. The gNB sends RRCReconfiguration to the remote UE via the relay UE to set up the relay SRB2 / DRB. The remote UE sends RRCReconfigurationComplete to the gNB via the relay UE as a response.

[0136] In addition to the concatenation setup procedure, for L2 UE-to-Network Relay:

[0137] - The RRC reconfiguration and RRC disconnection procedures reuse the legacy RRC procedures with the message content / configuration design remaining in the WI step.

[0138] - The RRC connection re-establishment and RRC connection resumption procedures reuse the conventional RRC procedures as a baseline, taking into account the aforementioned L2 UE-to-Network Relay connection establishment procedure to handle the relay-specific parts along with the message content / configuration design. Message content / configuration will be defined in the future.

[0139] An example of a direct to indirect path switch is shown in Figure 13. For service continuity of L2 UE-to-Network Relay, when a remote UE switches to an indirect relay UE, it follows the procedure in Figure 13.

[0140] 13, in step S1301, after the remote UE measures / discovers candidate relay UEs, the remote UE reports one or more candidate relay UEs. The remote UE filters suitable relay UEs that meet higher layer criteria when reporting. The report includes the ID and SL RSRP information of the relay UE, and the details of PC5 measurement will be determined in the future.

[0141] In step S1302, the gNB decides to switch to the target relay UE, and a target (re)configuration is selectively sent to the relay UE.

[0142] In step S1304, the RRC reconfiguration message to the remote UE includes the ID of the target relay UE, the target Uu and the PC5 configuration.

[0143] In step S1305, if a connection has not been established yet, the remote UE establishes a connection between the target relay UE and PC5.

[0144] In step S1306, the remote UE feeds back RRCReconfigurationComplete to the gNB via the target path using the target configuration provided by RRCReconfiguration.

[0145] In step S1307, the data path is switched.

[0146] Tables 13 to 16 are 3GPP technical reports on UE-to-UE relay selection, and are used as prior art for the present disclosure. Table 14 corresponds to FIG. 14, and Table 16 corresponds to FIG. 15.

[0147] [Table 13]

[0148] [Table 14]

[0149] [Table 15]

[0150] [Table 16]

[0151] On the other hand, when the remote UE establishes a PC5 unicast link with the relay UE and transmits / receives sidelink data to / from the base station through the relay UE (or attempts to start transmitting / receiving data), or when the relay UE establishes a connection with the base station in the path switching procedure shown in FIG. 13, the relay UE receives an RRC release or an RRC rejection from the base station. In this case, the remote UE cannot communicate with the base station through the relay UE, but since the various circumstances are unclear, it is unclear whether to wait while maintaining the PC5 connection with the relay UE or to perform a relay reselection procedure. Various embodiments of the present disclosure related to this will be described below.

[0152] According to an embodiment, a relay UE establishes a PC5 unicast link with a remote UE (S1601 in FIG. 16) and transmits an RRC setup request to a first base station (S1602). The relay UE receives an RRC rejection message including a first waiting time from the first base station (S1603). Based on receiving the RRC rejection message, the relay UE transmits a first notification message to the remote UE (S1604).

[0153] Here, the first notification message includes a second waiting time based on the first waiting time received by the relay UE from the first base station. The relay UE receives a request related to the release of the PC5 unicast link from the remote UE after the second waiting time ends. The request related to the release of the PC5 unicast link is transmitted by the remote UE after a time in which a predetermined offset is applied to the waiting time has elapsed. The request for the release of the PC5 unicast link is received by an RRCReconfigurationSidelink message. That is, the first waiting time is related to the remote UE's decision to release the PC5 unicast link.

[0154] In short, when the relay UE receives a rejection message regarding access from the gNB, it notifies the remote UE of the same. In this case, if the relay UE transmits the waiting time set in the relay UE together with the notification message (or includes the notification message) to the remote UE, the remote UE knows how long it can maintain the link currently established with the relay UE, which is helpful for the link management of the remote UE.

[0155] As described above, the link management of the remote UE means a decision as to whether the remote UE waits for the relay UE to establish an RRC connection with the base station while maintaining the PC5 unicast link with the relay UE, or releases the PC5 unicast link with the relay UE. If the remote UE decides to release the PC5 unicast link with the relay UE, this is performed at any one of the following points: after receiving a first notification, after the second waiting time has ended (elapsed), or after a time in which a predetermined offset has been applied to the second waiting time has elapsed.

[0156] That is, the relay UE that receives the rejection message notifies the remote UE along with the waiting time (Normal), and the remote UE that receives this can release the link with the relay UE, or can reject the link after waiting the waiting time. Alternatively, the remote UE can release the link after waiting an additional predetermined offset to the waiting time received from the relay UE. For example, when the relay UE starts counting the T302 timer, it notifies the remote UE and transmits the waiting time together.

[0157] Also, the relay UE that receives the RRC rejection message together with the waiting time may send a notification message to the remote UE after the waiting time expires, i.e., the first notification message is sent after the first waiting time has elapsed.

[0158] In addition, an RRC_INACTIVE remote UE that receives a notification message from a relay UE can also perform RRC Resume.

[0159] When a remote UE receives a notification message related to HO / RLF from a relay UE, it can maintain a connection with the relay UE. In this case, the time to maintain the link with the relay UE is the (+)offset time of the timer related to the operation (e.g., T304, T310).

[0160] The T302 timer is a timer defined in 3GPP TS 38.331, and is started upon receipt of an RRCReject or RRCRelease message. Table 17 below describes conditions for starting, stopping, and expiring various timers, including T302, and for further details, refer to standard document 3GPP TS 38.331.

[0161] [Table 17-1] [Table 17-2]

[0162] Meanwhile, the relay UE establishes an RRC connection with a second base station after the first waiting time has elapsed. The relay UE transmits a PC5 RRC message notifying the release to the remote UE based on receiving a release message from the second base station. After receiving the PC5 RRC message, the relay UE transmits a second notification to the remote UE based on receiving a message other than an RRCReestablishmentRequest, an RRCResumeRequest, or an RRCSetupRequest from the relay UE.

[0163] In other words, when the relay UE receives a release message from the gNB (and / or when the relay UE becomes IDLE / INACTIVE state), it notifies the remote UE connected to the relay UE via SL. The message used at this time can be a PC5-RRC / PC5-S message. When the relay UE is released, the remote UE cannot connect to the base station via the current relay UE, so it may need information about the release of the relay UE. When the remote UE continues to transmit data messages for relaying despite receiving a release message from the gNB (without an RRCReestablishmentRequest, RRCResumeRequest, or RRCSetupRequest message), the relay UE needs to notify the remote UE that the relay UE is in a released state. In this case, the relay UE transmits a notification message to the remote UE to notify that it is in a released state, and the remote UE that receives this message considers itself to be released and may perform an RRCReestablishmentRequest, RRCResumeRequest, RRCSetupRequest, or the like.

[0164] If the relay UE cannot transmit a message received from the base station to the remote UE, the relay UE may notify the base station of the failure. Alternatively, if the relay UE fails to transmit a message that the remote UE is to transmit to the base station, the relay UE may notify the remote UE of the failure. That is, the relay UE transmits a third notification to the remote UE to notify the remote UE of the failure based on the failure of the message transmission of the remote UE to the second base station. This may be limited to only transmitting an RRC message. That is, the message corresponds to an RRC message. For example, if the remote UE receives an RRC release message via the relay UE and transmits an RLC ACK in the upper layer in response to the RRC release message, but fails to transmit the RLC ACK to the gNB from the relay UE, the remote UE is notified of the failure. In this case, the remote UE may operate an inactive timer and recognize that it is in a released state after the inactive timer expires. This is to align the states of the gNB and the remote UE.

[0165] Alternatively, if the remote UE sends an RRCConnectionSetupComplete message to the gNB via the relay UE, but the relay UE fails to send the message to the gNB, the remote UE may be informed of this. In this case, the remote UE may also send the RRCConnectionSetupComplete message on a direct link. This operation may also be applied when sending messages such as ResumeComplete.

[0166] Although the above-mentioned embodiment regarding release describes that the relay UE receives an RRC rejection from the first base station and establishes an RRC connection with the second base station, this is not necessarily limited to this, and it may be assumed that the relay UE receives a release message from a specific base station regardless of the RRC rejection.

[0167] According to the above embodiment, the remote UE can efficiently determine how long to maintain the SL connection based on the wait time. Also, when the remote UE switches the path, if the cell of the relay UE changes, the operation of the relay UE and the remote UE is defined, thereby eliminating uncertainty in the operation of the relay UE and the remote UE.

[0168] In relation to the above description, the relay UE includes at least one processor and at least one computer memory operatively connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations, the operations including: establishing a PC5 unicast link with a remote UE; sending an RRC setup request to a first base station; receiving an RRC reject message from the first base station, the RRC reject message including a first waitTime; and sending a first notification message to the remote UE based on the reception of the RRC reject message, the first notification message including a second waitTime based on the first waitTime received by the relay UE from the first base station.

[0169] Hereinafter, an embodiment of a method for a relay UE to become a candidate relay UE / a method for being selected as a relay UE in SL UE-to-UE relay will be described.

[0170] A relay UE that receives a DCR ( / discovery solicitation) message from an SRC remote UE (UE-1 in Figures 14 and 15) can operate as a candidate UE-to-UE relay if it satisfies at least one of the following conditions 1) to 5).

[0171] 1) When the signal strength (DCR / discovery / discovery solicitation messages can be used) measured between the SRC remote UE and the relay UE is within a certain threshold range (e.g., threshold_X < measured signal strength < threshold_Y). The reason for limiting the signal strength range is to prevent an excessive number of relay UEs from becoming candidate relay UEs due to candidate relay UEs that are too close to the SRC remote UE responding.

[0172] 2) If the size of the signal strength measured between the SRC remote UE and the relay UE (in this case, DCR / discovery / discovery solicitation messages can be used) is equal to or greater than a predefined threshold (e.g., threshold_X < measured signal strength).

[0173] 3) When the SRC remote UE requests a service supported by the upper layer of the relay UE, this is to allow the relay UE to be configured to relay only specific services rather than relaying all services.

[0174] 4) When the number of SLs (for relay operation / pure) currently connected to the relay UE does not exceed the configured number (RRC dedicated / pre-defined, SIB). This is to prevent excessive load from being placed on one relay UE due to too many SLs being connected to it.

[0175] 5) When the PDB of a message (DCR / discovery) received from the SRC remote UE does not exceed the configured value (or 1 / 2 of the configured value), this is to prevent QoS from being unsatisfied when sending a message via the relay UE.

[0176] The conditions for becoming a relay UE can be applied not only to a message (DCR / discovery) transmitted from an SRC remote UE to a DST (Destination) remote UE (UE-2 in FIG. 14 and FIG. 15) via a relay UE, but also to a message transmitted from a DST remote UE to an SRC remote UE. That is, even if a UE becomes a candidate relay UE by satisfying the above conditions when transmitting a message transmitted by the SRC remote UE to the DST remote UE, if the UE does not satisfy the above conditions when transmitting a message transmitted by the DST remote UE to the SRC remote UE, the UE cannot become a candidate relay UE.

[0177] In order to prevent too many relay UEs from becoming candidate relay UEs for a message (DRC / discovery) sent by one SRC remote UE, the relay UE may perform the following operations.

[0178] Alternatively, if a relay UE that has received a message (DRC / discovery) from an SRC remote UE has a number of other relay UEs that have repeated the message of the same SRC remote UE that exceeds a set number of times, the relay UE may not repeat the message of the SRC remote UE. For example, there is a relay UE that can operate as a relay UE and has a monitoring repetition relay number set to 3. If the relay UE has received a message from an SRC remote UE, but three or more other relay UEs have already repeated the message, the relay UE may not repeat the message received from the SRC remote UE.

[0179] Also, when the monitoring repetition relay number set in each relay UE is the same, a case where all relay UEs do not repeat may occur (starvation). To prevent such a case, the monitoring repetition relay number set in each relay UE may be a value arbitrarily set for each relay UE within a predetermined range. For example, the monitoring repetition relay number is set to a value between 5 and 9, and each relay UE arbitrarily selects one of these values, and if other relay UEs are repeating the message (DCR / discovery) of the SRC remote UE that it received by that value, it does not have to operate as a candidate relay.

[0180] When a relay UE transmits a message (DCR / discovery or general message) received from an SRC remote UE ( / DST remote UE) to a DST remote UE ( / SRC remote UE), the relay UE can also transmit the signal strength it measured from the SRC remote UE in a repeat message. The value is used when the DST remote UE ( / RSC remote UE) selects a relay UE from the candidate relay UEs or when performing relay reselection.

[0181] When the DST remote UE selects a relay UE, it may select it as its own relay UE if the signal strength between the relay UE and the DST remote UE is within the signal strength range of a configured (pre-configuration, SIB information, RRC dedicated information) value, or it may select it as its own relay UE only if the signal strength exceeds a minimum signal strength.

[0182] If the SL signal strength of an indirect signal measured by a DST( / SRC) remote UE exceeds a predetermined threshold and the SL signal strength of a direct signal also exceeds a predetermined threshold, the remote UE may preferentially select the direct link.

[0183] By using the above-mentioned method for a relay UE to become a candidate relay UE, the criteria for selecting one relay UE, and the embodiment for preventing too many relay UEs from becoming candidate relay UEs, the remote UE can select an appropriate relay UE, and by preventing too many relay UEs from becoming candidate relay UEs, excessive load on the channel can also be prevented.

[0184] An example of a communication system to which the present invention is applied

[0185] Without being limited thereto, the various descriptions, functions, procedures, suggestions, methods and / or flow charts of the present invention disclosed in this specification may be applied to various fields requiring wireless communication / connection between devices (e.g., 5G).

[0186] Hereinafter, a more detailed description will be given with reference to the drawings. In the following drawings / description, the same reference numerals denote the same or corresponding hardware blocks, software blocks or function blocks, unless otherwise specified.

[0187] FIG. 17 illustrates a communication system 1 to which the present invention is applied.

[0188] Referring to FIG. 17, the communication system 1 applied to the present invention includes wireless devices, base stations, and networks. Here, the wireless devices refer to devices that communicate using wireless connection technology (e.g., 5G NR, LTE), and are also referred to as communication / wireless / 5G devices. The wireless devices include, but are not limited to, a robot 100a, vehicles 100b-1, 100b-2, an XR (eXtended Reality) device 100c, a handheld device (Hand-held Device) 100d, a home appliance 100e, an IoT (Internet of Thing) device 100f, and an AI device / server 400. For example, the vehicles include vehicles equipped with wireless communication functions, autonomous vehicles, vehicles capable of inter-vehicle communication, and the like. Here, the vehicles include UAVs (Unmanned Aerial Vehicles) (e.g., drones). XR devices include Augmented Reality (AR) / Virtual Reality (VR) / Mixed Reality (MR) devices, and are embodied in the form of Head-Mounted Devices (HMDs), Head-Up Displays (HUDs) mounted on vehicles, TVs, smartphones, computers, wearable devices, home appliances, digital billboards, vehicles, robots, etc. Portable devices include smartphones, smart pads, wearable devices (e.g., smart watches, smart glasses), computers (e.g., notebook computers, etc.), etc. Home appliances include TVs, refrigerators, washing machines, etc. IoT devices include sensors, smart meters, etc. For example, base stations and networks may also be embodied as wireless devices, and a specific wireless device 200a may operate as a base station / network node for other wireless devices.

[0189] The wireless devices 100a to 100f are connected to a network 300 via a base station 200. AI (Artificial Intelligence) technology is applied to the wireless devices 100a to 100f, and the wireless devices 100a to 100f are connected to an AI server 400 via the network 300. The network 300 is configured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g., NR) network. The wireless devices 100a to 100f can communicate with each other via the base station 200 / network 300, but can also communicate directly without going through the base station / network (e.g., sidelink communication). For example, the vehicles 100b-1 and 100b-2 can communicate directly (e.g., V2V (Vehicle to Vehicle) / V2X (Vehicle to everything) communication). Also, an IoT device (e.g., a sensor) can directly communicate with another IoT device (e.g., a sensor) or another wireless device 100a to 100f.

[0190] Wireless communication / connections 150a, 150b, and 150c are performed between the wireless devices 100a to 100f / base stations 200 and the base stations 200. Here, the wireless communication / connections are performed by various wireless connection technologies such as uplink / downlink communication 150a and sidelink communication 150b (or D2D communication) and inter-base station communication 150c (e.g., relay, IAB (Integrated Access Backhaul) (e.g., 5G NR). Through the wireless communication / connections 150a, 150b, and 150c, the wireless devices and base stations, and the base stations and base stations can transmit / receive wireless signals to each other. For example, the wireless communication / connections 150a, 150b, and 150c can transmit / receive signals via various physical channels. To this end, any one of various configuration information setting processes for transmitting / receiving wireless signals, various signal processing processes (e.g., channel coding / decoding, modulation / demodulation, resource mapping / demapping, etc.), and resource allocation processes is performed based on various proposals of the present invention.

[0191] Examples of wireless devices to which the present invention can be applied

[0192] FIG. 18 illustrates a wireless device to which the present invention is applied.

[0193] 18, a first wireless device 100 and a second wireless device 200 transmit and receive wireless signals according to various wireless access technologies (e.g., LTE, NR), where {first wireless device 100, second wireless device 200} corresponds to {wireless device 100x, base station 200} and / or {wireless device 100x, wireless device 100x} in FIG.

[0194] The first wireless device 100 includes one or more processors 102 and one or more memories 104, and further includes one or more transceivers 106 and / or one or more antennas 108. The processor 102 is configured to control the memory 104 and / or the transceiver 106 to implement the descriptions, functions, procedures, suggestions, methods, and / or flowcharts disclosed herein. For example, the processor 102 processes information in the memory 104 to generate a first information / signal, and then transmits a wireless signal including the first information / signal via the transceiver 106. The processor 102 also receives a wireless signal including a second information / signal via the transceiver 106, and then stores information obtained from signal processing of the second information / signal in the memory 104. The memory 104 is coupled to the processor 102 and stores various information related to the operation of the processor 102. For example, the memory 104 stores software code including instructions for performing some or all of the processes controlled by the processor 102 or for performing the descriptions, functions, procedures, suggestions, methods, and / or flowcharts disclosed herein. Here, the processor 102 and memory 104 are part of a communication modem / circuit / chip designed to implement a wireless communication technology (e.g., LTE, NR). The transceiver 106 is coupled to the processor 102 and transmits and / or receives wireless signals via one or more antennas 108. The transceiver 106 includes a transmitter and / or a receiver. The transceiver 106 may also be referred to as an RF (radio frequency) unit. In the present invention, a wireless device may also refer to a communication modem / circuit / chip.

[0195] The second wireless device 200 includes one or more processors 202 and one or more memories 204, and further includes one or more transceivers 206 and / or one or more antennas 208. The processor 202 is configured to control the memory 204 and / or the transceiver 206 to implement the descriptions, functions, procedures, suggestions, methods, and / or flowcharts disclosed herein. For example, the processor 202 processes information in the memory 204 to generate a third information / signal, and then transmits a wireless signal including the third information / signal via the transceiver 206. The processor 202 also receives a wireless signal including a fourth information / signal via the transceiver 206, and then stores information obtained from the signal processing of the fourth information / signal in the memory 204. The memory 204 is coupled to the processor 202 and stores various information related to the operation of the processor 202. For example, the memory 204 stores software code including instructions for performing some or all of the processes controlled by the processor 202 or for performing the descriptions, functions, procedures, suggestions, methods, and / or flowcharts disclosed herein. Here, the processor 202 and memory 204 are part of a communication modem / circuit / chip designed to implement a wireless communication technology (e.g., LTE, NR). The transceiver 206 is coupled to the processor 202 and transmits and / or receives wireless signals via one or more antennas 208. The transceiver 206 includes a transmitter and / or a receiver. The transceiver 206 may also be referred to as an RF unit. In the present invention, a wireless device may also refer to a communication modem / circuit / chip.

[0196] The hardware components of the wireless device 100, 200 are described in more detail below. One or more protocol layers may be implemented by, but are not limited to, one or more processors 102, 202. For example, the one or more processors 102, 202 may implement one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, SDAP, etc.). The one or more processors 102, 202 may generate one or more Protocol Data Units (PDUs) and / or one or more Service Data Units (SDUs) according to the descriptions, functions, procedures, suggestions, methods, and / or flowcharts disclosed herein. The one or more processors 102, 202 may generate messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods, and / or flowcharts disclosed herein. The one or more processors 102, 202 may generate and provide signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data or information according to the functions, procedures, suggestions, and / or methods disclosed herein to the one or more transceivers 106, 206. The one or more processors 102, 202 may receive signals (e.g., baseband signals) from the one or more transceivers 106, 206 and derive the PDUs, SDUs, messages, control information, data or information according to the descriptions, functions, procedures, suggestions, methods and / or flowcharts disclosed herein.

[0197] The one or more processors 102, 202 may also be referred to as controllers, microcontrollers, microprocessors, or microcomputers. The one or more processors 102, 202 may be implemented using hardware, firmware, software, or a combination thereof. As an example, the one or more processors 102, 202 may include 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). The descriptions, functions, procedures, suggestions, methods, and / or flowcharts disclosed herein may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, and the like. The firmware or software configured to perform the descriptions, functions, procedures, suggestions, methods, and / or flowcharts disclosed herein may be included in the one or more processors 102, 202, or may be stored in one or more memories 104, 204 and executed by the one or more processors 102, 202. The descriptions, functions, procedures, suggestions, methods and / or flow charts disclosed in this specification may be embodied using firmware or software in the form of code, instructions and / or sets of instructions.

[0198] The one or more memories 104, 204 are coupled to the one or more processors 102, 202 and store various types of data, signals, messages, information, programs, code, instructions, and / or commands. The one or more memories 104, 204 may be comprised of ROM, RAM, EPROM, flash memory, hard drives, registers, cache memory, computer readable storage media, and / or combinations thereof. The one or more memories 104, 204 may be located internal and / or external to the one or more processors 102, 202. Additionally, the one or more memories 104, 204 may be coupled to the one or more processors 102, 202 via various techniques, such as wired or wireless connections.

[0199] One or more transceivers 106, 206 may transmit user data, control information, wireless signals / channels, etc., as described in the methods and / or flow charts, etc., herein to one or more other devices. One or more transceivers 106, 206 may receive user data, control information, wireless signals / channels, etc., as described in the descriptions, functions, procedures, suggestions, methods and / or flow charts, etc., herein from one or more other devices. For example, one or more transceivers 106, 206 may be coupled to one or more processors 102, 202 to transmit and receive wireless signals. For example, one or more processors 102, 202 may control one or more transceivers 106, 206 to transmit user data, control information, or wireless signals to one or more other devices. Also, one or more processors 102, 202 may control one or more transceivers 106, 206 to receive user data, control information, or wireless signals from one or more other devices. The one or more transceivers 106, 206 are coupled to one or more antennas 108, 208, and the one or more transceivers 106, 206 are configured to transmit and receive user data, control information, radio signals / channels, etc., as described, functions, procedures, suggestions, methods and / or flow charts disclosed herein, via the one or more antennas 108, 208. In this specification, the one or more antennas can be multiple physical antennas or multiple logical antennas (e.g., antenna ports). The one or more transceivers 106, 206 convert the received user data, control information, radio signals / channels, etc., from RF band signals to baseband signals for processing by the one or more processors 102, 202. The one or more transceivers 106, 206 convert the user data, control information, radio signals / channels, etc., processed by the one or more processors 102, 202, from baseband signals to RF band signals. To this end, the one or more transceivers 106, 206 include (analog) oscillators and / or filters.

[0200] Examples of vehicles or autonomous vehicles to which the present invention is applied

[0201] 19 illustrates an example of a vehicle or an autonomous vehicle to which the present invention is applied. The vehicle or the autonomous vehicle may be realized as a mobile robot, a car, a train, an aerial vehicle (AV), a ship, or the like.

[0202] 19, a vehicle or an autonomous vehicle 100 includes an antenna unit 108, a communication unit 110, a control unit 120, a driving unit 140a, a power supply unit 140b, a sensor unit 140c, and an autonomous driving unit 140d. The antenna unit 108 is formed as a part of the communication unit 110.

[0203] The communication unit 110 transmits and receives signals (e.g., data, control signals, etc.) to and from external devices such as other vehicles, base stations (e.g., base stations, road side units, etc.), and servers. The control unit 120 controls elements of the vehicle or autonomous vehicle 100 to perform various operations. The control unit 120 includes an ECU (Electronic Control Unit). The driving unit 140a causes the vehicle or autonomous vehicle 100 to run on the ground. The driving unit 140a includes an engine, a motor, a power train, wheels, brakes, a steering device, etc. The power supply unit 140b supplies power to the vehicle or autonomous vehicle 100 and includes wired / wireless charging circuits, a battery, etc. The sensor unit 140c can obtain vehicle status, surrounding environment information, user information, etc. The sensor unit 140c includes an IMU (inertial measurement unit) sensor, a collision sensor, a wheel sensor, a speed sensor, a tilt sensor, a weight sensor, a heading sensor, a position module, a vehicle forward / reverse sensor, a battery sensor, a fuel sensor, a tire sensor, a steering sensor, a temperature sensor, a humidity sensor, an ultrasonic sensor, an illuminance sensor, a pedal position sensor, etc. The autonomous driving unit 140d embodies a technology for maintaining a lane while driving, a technology for automatically adjusting speed such as an adaptive cruise control, a technology for automatically driving according to a predetermined route, a technology for automatically setting a route when a destination is set, and the like.

[0204] For example, the communication unit 110 receives map data, traffic information data, etc. from an external server. The autonomous driving unit 140d generates an autonomous driving route and a drive plan based on the obtained data. The control unit 120 controls the driving unit 140a (e.g., speed / direction adjustment) so that the vehicle or autonomous driving vehicle 100 moves along the autonomous driving route according to the drive plan. The communication unit 110 non-periodically obtains the latest traffic information data from an external server during autonomous driving, and also obtains surrounding traffic information data from surrounding vehicles. In addition, the sensor unit 140c obtains vehicle status and surrounding environment information during autonomous driving. The autonomous driving unit 140d updates the autonomous driving route and the drive plan based on the newly obtained data / information. The communication unit 110 transmits information regarding the vehicle position, the autonomous driving route, the drive plan, etc. to the external server. The external server can predict traffic information data in advance using AI technology, etc. based on information collected from the vehicle or autonomous driving vehicle, and provide the predicted traffic information data to the vehicle or autonomous driving vehicle.

[0205] Examples of AR / VR and vehicles to which the present invention is applied

[0206] 20 shows an example of a vehicle to which the present invention is applied. The vehicle may be embodied as a transportation means, a train, an aircraft, a ship, etc.

[0207] Referring to FIG. 20, a vehicle 100 includes a communication unit 110, a control unit 120, a memory unit 130, an input / output unit 140a, and a position measurement unit 140b.

[0208] The communication unit 110 transmits and receives signals (e.g., data, control signals, etc.) to and from external devices such as other vehicles or base stations. The control unit 120 can control the components of the vehicle 100 to perform various operations. The memory unit 130 stores data / parameters / programs / codes / instructions that support various functions of the vehicle 100. The input / output unit 140a outputs AR / VR objects based on information in the memory unit 130. The input / output unit 140a includes a HUD. The position measurement unit 140b can obtain position information of the vehicle 100. The position information includes absolute position information of the vehicle 100, position information within a driving line, acceleration information, position information relative to surrounding vehicles, etc. The position measurement unit 140b includes a GPS and various sensors.

[0209] For example, the communication unit 110 of the vehicle 100 receives map information, traffic information, etc. from an external server and stores it in the memory unit 130. The position measurement unit 140b obtains vehicle position information using GPS and various sensors and stores it in the memory unit 130. The control unit 120 generates a virtual object based on the map information, traffic information, vehicle position information, etc., and the input / output unit 140a displays the generated virtual object in a window inside the vehicle (1410, 1420). The control unit 120 also determines whether the vehicle 100 is operating correctly within the driving line based on the vehicle position information. If the vehicle 100 deviates abnormally from the driving line, the control unit 120 displays a warning on a window inside the vehicle through the input / output unit 140a. The control unit 120 also broadcasts a warning message regarding driving abnormality to surrounding vehicles through the communication unit 110. Depending on the situation, the control unit 120 can also transmit vehicle position information and information regarding driving / vehicle abnormality to relevant organizations through the communication unit 110.

[0210] Examples of XR devices to which the present invention can be applied

[0211] 21 illustrates an example of an XR device to which the present invention is applied. The XR device may be realized in the form of an HMD, a head-up display (HUD) installed in a vehicle, a TV, a smartphone, a computer, a wearable device, a home appliance, a digital signboard, a vehicle, a robot, etc.

[0212] Referring to FIG. 21, the XR device 100a includes a communication unit 110, a control unit 120, a memory unit 130, an input / output unit 140a, a sensor unit 140b, and a power supply unit 140c.

[0213] The communication unit 110 can transmit and receive signals (e.g., media data, control signals, etc.) to and from external devices such as other wireless devices, mobile devices, or media servers. Media data includes video, images, sounds, etc. The control unit 120 controls the components of the XR device 100a to perform various operations. For example, the control unit 120 is configured to control and / or perform procedures such as video / image acquisition, (video / image) encoding, metadata generation and processing, etc. The memory unit 130 stores data / parameters / programs / codes / commands required for driving the XR device 100a / generating XR objects. The input / output unit 140a obtains control information, data, etc. from the outside and outputs the generated XR objects. The input / output unit 140a includes a camera, a microphone, a user input unit, a display unit, a speaker, and / or a haptics module, etc. The sensor unit 140b obtains the XR device state, surrounding environment information, user information, etc. The sensor unit 140b includes a proximity sensor, an illuminance sensor, an acceleration sensor, a magnetic sensor, a gyro sensor, an inertial sensor, an RGB sensor, an IR sensor, a fingerprint recognition sensor, an ultrasonic sensor, a light sensor, a microphone, and / or a radar, etc. The power supply unit 140c supplies power to the XR device 100a and includes a wired / wireless charging circuit, a battery, etc.

[0214] As an example, the memory unit 130 of the XR device 100a includes information (e.g., data, etc.) required to generate an XR object (e.g., an AR / VR / MR object). The input / output unit 140a can obtain an instruction to operate the XR device 100a from a user, and the control unit 120 drives the XR device 100a according to the user's driving instruction. For example, when a user watches a movie, news, etc. through the XR device 100a, the control unit 120 can transmit content request information to another device (e.g., the portable device 100b) or a media server through the communication unit 130. The communication unit 130 can download / stream content such as movies, news, etc. from another device (e.g., the portable device 100b) or a media server to the memory unit 130. The control unit 120 controls and / or performs procedures such as video / image acquisition, (video / image) encoding, and metadata generation / processing for the content, and generates / outputs an XR object based on information about the surrounding space or real object obtained by the input / output unit 140a / sensor unit 140b.

[0215] The XR device 100a is wirelessly connected to the portable device 100b via the communication unit 110, and the operation of the XR device 100a is controlled by the portable device 100b. For example, the portable device 100b operates as a controller for the XR device 100a. For this reason, the XR device 100a can obtain three-dimensional position information of the portable device 100b, and then generate and output an XR individual corresponding to the portable device 100b.

[0216] Examples of robots to which the present invention can be applied

[0217] Figure 22 shows an example of a robot to which the present invention can be applied. Robots can be classified into industrial, medical, domestic, military, etc., depending on the purpose or field of use.

[0218] Referring to FIG. 22, the robot 100 includes a communication unit 110, a control unit 120, a memory unit 130, an input / output unit 140a, a sensor unit 140b, and a driving unit 140c.

[0219] The communication unit 110 transmits and receives signals (e.g., driving information, control signals, etc.) to and from external devices such as other wireless devices, other robots, or a control server. The control unit 120 controls the components of the robot 100 to perform various operations. The memory unit 130 stores data / parameters / programs / codes / commands that support various functions of the robot 100. The input / output unit 140a obtains information from outside the robot 100 and outputs information to the outside of the robot 100. The input / output unit 140a includes a camera, a microphone, a user input unit, a display unit, a speaker, and / or a haptics module. The sensor unit 140b obtains internal information of the robot 100, surrounding environment information, user information, etc. The sensor unit 140b includes a proximity sensor, an illuminance sensor, an acceleration sensor, a magnetic sensor, a gyro sensor, an inertial sensor, an IR sensor, a fingerprint recognition sensor, an ultrasonic sensor, a light sensor, a microphone, a radar, etc. The driving unit 140c performs various physical operations such as moving the robot joints. The driving unit 140c can make the robot 100 run on the ground or fly in the air. The driving unit 140c includes actuators, motors, wheels, brakes, propellers, and the like.

[0220] Examples of AI devices to which this invention can be applied

[0221] Figure 23 illustrates an example of an AI device to which the present invention can be applied. The AI ​​device may be implemented as a fixed device or a mobile device such as a TV, a projector, a smartphone, a PC, a notebook computer, a digital broadcasting terminal, a tablet PC, a wearable device, a set-top box (STB), a radio, a washing machine, a refrigerator, a digital signage, a robot, or a vehicle.

[0222] Referring to FIG. 23, the AI ​​device 100 includes a communication unit 110, a control unit 120, a memory unit 130, an input / output unit 140a / 140b, a running processor unit 140c, and a sensor unit 140d.

[0223] The communication unit 110 transmits and receives wired and wireless signals (e.g., sensor information, user input, learning model, control signal, etc.) to and from external devices such as other AI devices (e.g., 100x, 200, 400 in FIG. 17) and AI servers (e.g., 400 in FIG. 17) using wired and wireless communication technology. To this end, the communication unit 110 transmits information in the memory unit 130 to the external devices, or transfers signals received from the external devices to the memory unit 130.

[0224] The control unit 120 determines one of the executable operations of the AI ​​device 100 based on information determined or generated using a data analysis algorithm or a machine learning algorithm. The control unit 120 can also control the components of the AI ​​device 100 to perform the determined operation. For example, the control unit 120 can request, search, receive or use data from the running processor unit 140c or the memory unit 130, and can control the components of the AI ​​device 100 to perform a predicted operation or an operation determined to be desirable among one of the executable operations. The control unit 120 can also collect history information including the operation content of the AI ​​device 100 and user feedback on the operation, and store it in the memory unit 130 or the running processor unit 140c, or transmit it to an external device such as an AI server (FIG. 17, 400). The collected history information is used when updating a learning model.

[0225] The memory unit 130 stores data supporting various functions of the AI ​​device 100. For example, the memory unit 130 stores data obtained from the input unit 140a, data obtained from the communication unit 110, output data of the running processor unit 140c, and data obtained from the sensing unit 140. The memory unit 130 also stores control information and / or software codes required for the operation / execution of the control unit 120.

[0226] The input unit 140a obtains various types of data from outside the AI ​​device 100. For example, the input unit 140a obtains learning data for model learning and input data to which a learning model is applied. The input unit 140a includes a camera, a microphone, and / or a user input unit. The output unit 140b generates an output related to vision, hearing, touch, and the like. The output unit 140b includes a display unit, a speaker, and / or a haptics module. The sensing unit 140 obtains any one of internal information of the AI ​​device 100, information on the surrounding environment of the AI ​​device 100, and user information using various sensors. The sensing unit 140 includes a proximity sensor, an illuminance sensor, an acceleration sensor, a magnetic sensor, a gyro sensor, an inertial sensor, an RGB sensor, an IR sensor, a fingerprint recognition sensor, an ultrasonic sensor, a light sensor, a microphone, and / or a radar.

[0227] The running processor unit 140c uses the learning data to train a model composed of an artificial neural network. The running processor unit 140c performs AI processing together with the running processor unit of the AI ​​server (FIG. 17, 400). The running processor unit 140c processes information received from an external device by the communication unit 110 and / or information stored in the memory unit 130. In addition, the output value of the running processor unit 140c is / is transmitted to an external device by the communication unit 110 and stored in the memory unit 130. [Industrial Applicability]

[0228] The above embodiment can be applied to various mobile communication systems.

Claims

1. 1. A method for operating a relay UE in a wireless communication system, comprising: The relay UE establishes a PC5 unicast link with the remote UE; The relay UE sends an RRC setup request to a first base station; The relay UE receives an RRC reject message from the first base station, the RRC reject message including a first wait time; and based on receiving the RRC rejection message, the relay UE sends a first notification message to the remote UE; Including, The method of claim 1, wherein the first notification message includes a second waiting time based on the first waiting time received by the relay UE from the first base station.

2. The method of claim 1 , wherein the relay UE receives a request related to the release of the PC5 unicast link from the remote UE after the second waiting time expires.

3. The method of claim 2 , wherein the request related to the release of the PC5 unicast link is sent by the remote UE after a time in which a predetermined offset is applied to the waiting time has elapsed.

4. The method of claim 2 , wherein the request to release the PC5 unicast link is received via an RRCReconfigurationSidelink message.

5. The method of claim 1 , wherein the second waiting time is related to a release decision of the remote UE of the PC5 unicast link.

6. The method of claim 1 , wherein the first notification message is sent after the first waiting time has elapsed.

7. The method of claim 1 , wherein the relay UE establishes an RRC connection with a second base station after the first waiting time has elapsed.

8. The method of claim 7, wherein the relay UE sends a PC5 RRC message to the remote UE notifying the release based on receiving a release message from the second base station.

9. 9. The method of claim 8, wherein the relay UE sends a second notification to the remote UE based on receiving a message other than an RRCReestablishmentRequest, an RRCResumeRequest, or an RRCSetupRequest from the relay UE after receiving the PC5 RRC message.

10. The method of claim 7, wherein the relay UE transmits a third notification to the remote UE based on a failure of the message delivery of the remote UE to the second base station, notifying the remote UE of the failure.

11. The method of claim 10 , wherein the message corresponds to an RRC message.

12. The method of claim 11 , wherein the message is a response to an RRC release message and is an RLC ACK message.

13. In a wireless communication system, a relay UE device is provided, At least one processor; and at least one computer memory operatively connected to said at least one processor and storing instructions that, when executed, cause said at least one processor to perform operations; The operation includes: Establish a PC5 unicast link with the remote UE; Sending an RRC setup request to the first base station; and receiving an RRC reject message from the first base station, the RRC reject message including a first wait time; and sending a first notification message to the remote UE based on receipt of the RRC rejection message; Including, The first notification message includes a second waiting time based on the first waiting time received by the relay UE from the first base station.

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