Communication terminal device and communication system

Abstract

The present invention provides a technology for implementing a service that uses terminal-to-terminal communication such as V2X communication. This communication system comprises: a base station that is configured to be able to communicate with a core network; and a communication terminal that is configured to be able to wirelessly communicate with the base station. The base station supports a non-public network. The communication terminal is configured to be able to implement a service that uses terminal-to-terminal communication. The communication terminal determines whether or not it is possible to access the base station, on the basis of information that indicates which of non-public networks makes various services available that use terminal-to-terminal communication.

Description

Technical Field

[0001] The present disclosure relates to wireless communication technology.

Background Art

[0002] In the 3GPP (3rd Generation Partnership Project), which is a standardization organization for mobile communication systems, the radio section is called Long Term Evolution (LTE), and for the overall system configuration including the core network and the radio access network (hereinafter collectively also referred to as the network), a communication method called System Architecture Evolution (SAE) is being studied (for example, Non-Patent Documents 1 to 5). This communication method is also called the 3.9G (3.9 Generation) system.

[0003] As the access method of LTE, OFDM (Orthogonal Frequency Division Multiplexing) is used in the downlink direction, and SC-FDMA (Single Carrier Frequency Division Multiple Access) is used in the uplink direction. Also, different from W-CDMA (Wideband Code Division Multiple Access), LTE does not include circuit switching and is only a packet communication method.

[0004] Regarding the decisions on frame configuration in the LTE system by 3GPP described in Non-Patent Document 1 (Chapter 5), it will be described with reference to FIG. 1. FIG. 1 is an explanatory diagram showing the configuration of a radio frame used in a communication system of the LTE method. In FIG. 1, one radio frame is 10 ms. The radio frame is divided into 10 subframes of equal size. The subframe is divided into two slots of equal size. The first and sixth subframes in each radio frame contain a downlink synchronization signal. The synchronization signal includes a primary synchronization signal (P-SS) and a secondary synchronization signal (S-SS).

[0005] The decisions on channel configuration in the LTE system by 3GPP are described in Non-Patent Document 1 (Chapter 5). It is assumed that the same channel configuration as that of a non-CSG cell is used even in a CSG (Closed Subscriber Group) cell.

[0006] The physical broadcast channel (PBCH) is a channel for downlink transmission from a base station device (hereinafter sometimes simply referred to as "base station") to a communication terminal device such as a mobile terminal device (hereinafter sometimes simply referred to as "mobile terminal") (hereinafter sometimes simply referred to as "communication terminal"). The BCH transport block is mapped to 4 subframes within a 40 ms interval. There is no explicit signaling for the 40 ms timing.

[0007] The Physical Control Format Indicator Channel (PCFICH) is a channel for downlink transmission from a base station to a communication terminal. The PCFICH notifies the number of OFDM (Orthogonal Frequency Division Multiplexing) symbols used for PDCCHs from the base station to the communication terminal. The PCFICH is transmitted for each subframe.

[0008] The Physical Downlink Control Channel (PDCCH) is a channel for downlink transmission from a base station to a communication terminal. The PDCCH notifies resource allocation information of the Downlink Shared Channel (DL-SCH), which is one of the transport channels described later, resource allocation information of the Paging Channel (PCH), which is one of the transport channels described later, and HARQ (Hybrid Automatic Repeat reQuest) information related to the DL-SCH. The PDCCH carries an Uplink Scheduling Grant. The PDCCH carries an Ack (Acknowledgement) / Nack (Negative Acknowledgement), which is a response signal for uplink transmission. The PDCCH is also called an L1 / L2 control signal.

[0009] The Physical Downlink Shared Channel (PDSCH) is a channel for downlink transmission from a base station to a communication terminal. The DL-SCH, which is a transport channel, and the PCH, which is a transport channel, are mapped to the PDSCH.

[0010] The Physical Multicast Channel (PMCH) is a channel for downlink transmission from a base station to a communication terminal. The Multicast Channel (MCH), which is a transport channel, is mapped to the PMCH.

[0011] The Physical Uplink Control Channel (PUCCH) is a channel for uplink transmission from a communication terminal to a base station. The PUCCH carries the Ack / Nack, which is a response signal for downlink transmission. The PUCCH also carries the Channel State Information (CSI). The CSI consists of the Rank Indicator (RI), the Precoding Matrix Indicator (PMI), and the Channel Quality Indicator (CQI) reports. The RI is the rank information of the channel matrix in MIMO. The PMI is the information of the precoding weight matrix used in MIMO. The CQI is the quality information indicating the quality of the received data or the channel quality. Additionally, the PUCCH carries the Scheduling Request (SR).

[0012] The Physical Uplink Shared Channel (PUSCH) is a channel for uplink transmission from a communication terminal to a base station. The Uplink Shared Channel (UL-SCH), which is one of the transport channels, is mapped to the PUSCH.

[0013] The Physical Hybrid ARQ Indicator Channel (PHICH) is a downlink channel from the base station to the communication terminal. The PHICH carries the Ack / Nack, which is a response signal for the uplink transmission. The Physical Random Access Channel (PRACH) is an uplink channel from the communication terminal to the base station. The PRACH carries the random access preamble.

[0014] The downlink reference signal (Reference Signal: RS) is a symbol known in the LTE communication system. The following five types of downlink reference signals are defined: the Cell-specific Reference Signal (CRS), the MBSFN Reference Signal, the Demodulation Reference Signal (DM-RS) which is the UE-specific Reference Signal, the Positioning Reference Signal (PRS), and the Channel State Information Reference Signal (CSI-RS). As a measurement at the physical layer of the communication terminal, there is the measurement of the Reference Signal Received Power (RSRP) of the reference signal.

[0015] Similarly, for the uplink reference signal, it is a symbol known in the LTE communication system. The following two types of uplink reference signals are defined: the Demodulation Reference Signal (DM-RS) and the Sounding Reference Signal (SRS).

[0016] The transport channel described in Non-Patent Document 1 (Chapter 5) will be explained. Among the downlink transport channels, the broadcast channel (BCH) is broadcast throughout the coverage area of the base station (cell). The BCH is mapped to the physical broadcast channel (PBCH).

[0017] For the downlink shared channel (DL-SCH), retransmission control by hybrid automatic repeat request (HARQ) is applied. The DL-SCH can be broadcast throughout the coverage area of the base station (cell). The DL-SCH supports dynamic or semi-static resource allocation. Semi-static resource allocation is also called persistent scheduling. The DL-SCH supports discontinuous reception (DRX) of the communication terminal for power consumption reduction of the communication terminal. The DL-SCH is mapped to the physical downlink shared channel (PDSCH).

[0018] The paging channel (PCH) supports DRX of the communication terminal to enable low power consumption of the communication terminal. The PCH requires broadcast throughout the coverage area of the base station (cell). The PCH is mapped to a physical resource such as the physical downlink shared channel (PDSCH) that can be dynamically used for traffic.

[0019] The multicast channel (MCH) is used for broadcast throughout the coverage area of the base station (cell). The MCH supports single-frequency network (SFN) synthesis of the multimedia broadcast multicast service (MTCH and MCCH) in multicell transmission. The MCH supports semi-static resource allocation. The MCH is mapped to the physical multicast channel (PMCH).

[0020] Among the uplink transport channels, for the uplink shared channel (UL-SCH), retransmission control by hybrid automatic repeat request (HARQ) is applied. The UL-SCH supports dynamic or semi-static resource allocation. The UL-SCH is mapped to the physical uplink shared channel (PUSCH).

[0021] The random access channel (RACH) is limited to control information. The RACH has a risk of collision. The RACH is mapped to the physical random access channel (PRACH).

[0022] An explanation of HARQ is given. HARQ is a technology that improves the communication quality of the transmission path by combining automatic repeat request (ARQ) and forward error correction. HARQ has the advantage that error correction functions effectively by retransmission even for a transmission path where the communication quality changes. In particular, it is also possible to obtain further quality improvement by combining the reception result of the first transmission and the reception result of the retransmission at the time of retransmission.

[0023] An example of the retransmission method is explained. On the receiving side, if the received data cannot be decoded correctly, in other words, if a cyclic redundancy check (CRC) error occurs (CRC = NG), the receiving side sends a "Nack" to the transmitting side. The transmitting side that receives the "Nack" retransmits the data. On the receiving side, if the received data can be decoded correctly, in other words, if no CRC error occurs (CRC = OK), the receiving side sends an "Ack" to the transmitting side. The transmitting side that receives the "Ack" transmits the next data.

[0024] The logical channel (Logical channel) described in Non-Patent Document 1 (Chapter 6) will be explained. The Broadcast Control Channel (BCCH) is a downlink channel for broadcast system control information. The BCCH, which is a logical channel, is mapped to the Broadcast Channel (BCH), which is a transport channel, or to the Downlink Shared Channel (DL-SCH).

[0025] The Paging Control Channel (PCCH) is a downlink channel for transmitting paging information and changes in system information. The PCCH is used when the network does not know the cell location of the communication terminal. The PCCH, which is a logical channel, is mapped to the Paging Channel (PCH), which is a transport channel.

[0026] The Common Control Channel (CCCH) is a channel for transmission control information between the communication terminal and the base station. The CCCH is used when the communication terminal does not have an RRC connection with the network. In the downlink direction, the CCCH is mapped to the Downlink Shared Channel (DL-SCH), which is a transport channel. In the uplink direction, the CCCH is mapped to the Uplink Shared Channel (UL-SCH), which is a transport channel.

[0027] The Multicast Control Channel (MCCH) is a downlink channel for one-to-many transmission. The MCCH is used for transmitting MBMS control information for one or several MTCHs from the network to the communication terminal. The MCCH is used only for communication terminals receiving MBMS. The MCCH is mapped to the Multicast Channel (MCH), which is a transport channel.

[0028] The Dedicated Control Channel (DCCH) is a channel that transmits dedicated control information between a communication terminal and a network on a one-to-one basis. The DCCH is used when the communication terminal is in an RRC connection. The DCCH is mapped to the UL-SCH in the uplink and to the DL-SCH in the downlink.

[0029] The Dedicated Traffic Channel (DTCH) is a channel for one-to-one communication to an individual communication terminal for the transmission of user information. The DTCH exists in both the uplink and the downlink. The DTCH is mapped to the UL-SCH in the uplink and to the DL-SCH in the downlink.

[0030] The Multicast Traffic channel (MTCH) is a downlink channel for the transmission of traffic data from the network to a communication terminal. The MTCH is a channel used only for communication terminals during MBMS reception. The MTCH is mapped to the Multicast Channel (MCH).

[0031] CGI stands for Cell Global Identifier. ECGI stands for E-UTRAN Cell Global Identifier. In LTE, LTE-A (Long Term Evolution Advanced) to be described later, and UMTS (Universal Mobile Telecommunication System), Closed Subscriber Group (CSG) cells are introduced.

[0032] The location tracking of a communication terminal is performed in units of areas each consisting of one or more cells. The location tracking is carried out to track the location of the communication terminal even in the standby state and to enable calling the communication terminal, in other words, to enable the communication terminal to be incoming-called. The area for this location tracking of the communication terminal is called a tracking area.

[0033] Also, in 3GPP, as Release 10, the standardization of Long Term Evolution Advanced (LTE-A) is in progress (see Non-Patent Document 3 and Non-Patent Document 4). LTE-A is based on the radio interval communication method of LTE and is configured by adding several new technologies thereto.

[0034] In the LTE-A system, in order to support a wider frequency bandwidth (transmission bandwidths) up to 100 MHz, carrier aggregation (CA) is being studied, which aggregates (also referred to as "aggregating") two or more component carriers (CCs). CA is described in Non-Patent Document 1.

[0035] When CA is configured, the UE has only one RRC connection with the network (NW). In the RRC connection, one serving cell provides NAS mobility information and security input. This cell is called the primary cell (PCell). In the downlink, the carrier corresponding to the PCell is the downlink primary component carrier (DL PCC). In the uplink, the carrier corresponding to the PCell is the uplink primary component carrier (UL PCC).

[0036] According to the capabilities of the UE, a Secondary Cell (SCell) is configured to form a set of serving cells together with the PCell. In the downlink, the carrier corresponding to the SCell is the Downlink Secondary Component Carrier (DL SCC). In the uplink, the carrier corresponding to the SCell is the Uplink Secondary Component Carrier (UL SCC).

[0037] A set of serving cells consisting of one PCell and one or more SCells is configured for one UE.

[0038] Also, as new technologies in LTE-A, there are technologies such as Wider bandwidth extension and Coordinated Multiple Point transmission and reception (CoMP) technology. Regarding CoMP being considered for LTE-A by 3GPP, it is described in Non-Patent Document 1.

[0039] Also, in 3GPP, in order to cope with future huge traffic, it is being considered to use small eNBs (hereinafter sometimes referred to as "small base station devices") that constitute small cells. For example, technologies such as increasing the frequency utilization efficiency and increasing the communication capacity by installing a large number of small eNBs to form a large number of small cells are being considered. Specifically, there is Dual Connectivity (abbreviated as DC) where the UE connects to two eNBs for communication. DC is described in Non-Patent Document 1.

[0040] Among the eNBs that perform dual connectivity (DC), one may be referred to as the "master eNB (abbreviated as MeNB)", and the other may be referred to as the "secondary eNB (abbreviated as SeNB)".

[0041] The traffic volume of the mobile network is on an increasing trend, and the communication speed is also accelerating. When LTE and LTE-A are fully launched into operation, it is expected that the communication speed will be further increased.

[0042] Furthermore, for the advanced mobile communication, a fifth-generation (hereinafter sometimes referred to as "5G") radio access system aiming to start services after 2020 is being studied. For example, in Europe, the requirements for 5G have been summarized by a group called METIS (see Non-Patent Document 5).

[0043] In the 5G radio access system, compared with the LTE system, the system capacity is 1000 times, the data transmission speed is 100 times, the data processing delay is one-tenth (1 / 10), and the number of simultaneously connected communication terminals is 100 times. Further reduction of power consumption and cost of the device are listed as requirements.

[0044] In order to meet such requirements, in 3GPP, the standard study of 5G is being advanced as Release 15 (see Non-Patent Documents 6 to 18). The technology of the 5G radio section is called "New Radio Access Technology" (abbreviated as "NR" for "New Radio").

[0045] The NR system is being studied based on the LTE system and the LTE-A system, but changes and additions from the LTE system and the LTE-A system are being made in the following aspects.

[0046] As the access method of NR, OFDM is used in the downlink direction, and OFDM and DFT-s-OFDM (DFT-spread-OFDM) are used in the uplink direction.

[0047] In NR, in order to improve the transmission speed and reduce the processing delay, it is possible to use a higher frequency compared to LTE.

[0048] In NR, by forming a narrow beam-like transmission and reception range (beamforming) and changing the direction of the beam (beam sweeping), cell coverage is ensured.

[0049] In the frame structure of NR, various subcarrier intervals, that is, various numerologies are supported. In NR, regardless of the numerology, one subframe is 1 millisecond, and one slot is composed of 14 symbols. Also, the number of slots included in one subframe is one in the numerology with a subcarrier interval of 15 kHz, and in other numerologies, it increases in proportion to the subcarrier interval (see Non-Patent Document 13 (TS38.211 V15.2.0)).

[0050] The downlink synchronization signal in NR is transmitted from the base station at a predetermined period with a predetermined duration as a Synchronization Signal Burst (hereinafter, may be referred to as an SS burst). The SS burst is composed of Synchronization Signal Blocks (hereinafter, may be referred to as SS blocks) for each beam of the base station. The base station transmits the SS blocks of each beam within the duration of the SS burst while changing the beam. The SS block is composed of P-SS, S-SS, and PBCH.

[0051] In NR, as a downlink reference signal in NR, by adding a Phase Tracking Reference Signal (PTRS), the influence of phase noise is reduced. Also, in the uplink reference signal, PTRS is added in the same way as in the downlink.

[0052] In NR, in order to flexibly perform DL / UL switching within a slot, Slot Format Indication (SFI) is added to the information included in the PDCCH.

[0053] Also, in NR, the base station pre-sets a part of the carrier frequency band (hereinafter sometimes referred to as Bandwidth Part (BWP)) for the UE, and the UE performs transmission and reception with the base station in the BWP, thereby reducing the power consumption of the UE.

[0054] In 3GPP, as forms of DC, DC by an LTE base station connected to the EPC and an NR base station, DC by an NR base station connected to a 5G core system, and DC by an LTE base station and an NR base station connected to a 5G core system are being studied (see Non-Patent Documents 12, 16, and 19).

[0055] Also, in 3GPP, several new technologies are being studied. For example, it is being studied to support V2X communication in both LTE and a 5G core system (Non-Patent Documents 1, 20, and 21). For example, connection to a Non-Public Network (NPN) etc. is being studied (see Non-Patent Documents 22 and 23).

Prior Art Documents

Non-Patent Documents

[0056]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Non-Patent Document 4

Non-Patent Document 5

Non-Patent Document 22

Non-Patent Document 23

Non-Patent Document 24

Non-Patent Document 25

Non-Patent Document 26

Non-Patent Document 27

Summary of the Invention

Problems to be Solved by the Invention

[0057] Supporting V2X communication in both LTE and 5G core systems has been considered (Non-Patent Documents 1, 20, 21). In V2X communication, sidelink communication (also referred to as PC5 communication) is supported. Enabling D2D communication using PC5 communication has been considered. When supporting PC5 communication, issues arise regarding how to meet the QoS requirements for services using PC5 communication and how to reduce interference between services.

[0058] Also, as described above, in 3GPP, the introduction of NPN using a 5G communication system (hereinafter sometimes referred to as a 5G system) has been considered. For example, introducing NPN using 5G indoors in factories and the like has been considered (see Non-Patent Document 24 (3GPP TR23.734 V16.2.0)). Also, constructing NPN indoors in factories and the like and supporting communication between a base station and a terminal or Device to Device Communication (D2D Communication) services within NPN have been required (see Non-Patent Document 25 (3GPP S1-191338), Non-Patent Document 26 (3GPP S1-191580)).

[0059] However, while the implementation method of V2X communication in the conventional public network has been disclosed, the implementation method of V2X communication in the NPN has not been disclosed. For example, access control is required in the NPN, but there is no disclosure at all about how to implement V2X communication in the NPN where access control is implemented. There arises a problem that V2X communication and D2D communication cannot be implemented within the NPN.

[0060] For this reason, there arises a problem that wireless communication technologies suitable for various industries, such as wireless communication and V2X communication within a factory, cannot be established.

[0061] In view of the above problems, one of the objectives of the present disclosure is to provide a technology for implementing services using inter-terminal communication such as V2X communication.

Means for Solving the Problems

[0062] According to the present disclosure, A communication terminal device in a communication system, the communication system including a plurality of communication terminal devices including the communication terminal device, the communication terminal device performing PC5 communication, which is communication via a PC5 interface, with another communication terminal device among the plurality of communication terminal devices, and the communication terminal device setting an expiration date for the resources of the PC5 communication. is provided.

Effects of the Invention

[0063] According to the present disclosure, it becomes possible to implement services using inter-terminal communication.

[0064] The objectives, features, aspects, and advantages of the present disclosure will become clearer from the following detailed description and the accompanying drawings.

Brief Description of the Drawings

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Embodiments for Carrying Out the Invention

[0066] Embodiment 1. Figure 2 is a block diagram showing the overall configuration of a communication system 200 of the LTE system being discussed in 3GPP. Figure 2 will be described. The radio access network is referred to as E-UTRAN (Evolved Universal Terrestrial Radio Access Network) 201. A mobile terminal device (hereinafter simply referred to as "mobile terminal (User Equipment: UE)") 202, which is a communication terminal device, can communicate wirelessly with a base station device (hereinafter referred to as "base station (E-UTRAN NodeB: eNB)") 203 and performs signal transmission and reception through wireless communication.

[0067] Here, the "communication terminal device" includes not only mobile terminal devices such as mobile phone terminal devices that can move, but also non-mobile devices such as sensors. In the following description, the "communication terminal device" may sometimes be simply referred to as the "communication terminal".

[0068] If the control protocol for the mobile terminal 202, for example, RRC (Radio Resource Control), and the user plane (hereinafter sometimes referred to as U-Plane), for example, PDCP (Packet Data Convergence Protocol), RLC (Radio Link Control), MAC (Medium Access Control), PHY (Physical layer) terminate at the base station 203, then the E-UTRAN is composed of one or more base stations 203.

[0069] The control protocol RRC (Radio Resource Control) between the mobile terminal 202 and the base station 203 performs functions such as broadcast, paging, and RRC connection management. As the states of the base station 203 and the mobile terminal 202 in RRC, there are RRC_IDLE and RRC_CONNECTED.

[0070] In RRC_IDLE, PLMN (Public Land Mobile Network) selection, system information (SI) notification, paging, cell re-selection, mobility, etc. are performed. In RRC_CONNECTED, the mobile terminal has an RRC connection and can transmit and receive data with the network. Also in RRC_CONNECTED, handover (HO), measurement of neighbor cells, etc. are performed.

[0071] The base station 203 is composed of one or more eNBs 207. Also, a system composed of the core network EPC (Evolved Packet Core) and the radio access network E-UTRAN 201 is called EPS (Evolved Packet System). Sometimes, the combination of the core network EPC and the radio access network E-UTRAN 201 is referred to as the "network".

[0072] The eNB 207 is connected to the Mobility Management Entity (MME), or the Serving Gateway (S-GW), or the MME / S-GW unit (hereinafter sometimes referred to as the "MME unit") 204 including the MME and the S-GW through the S1 interface, and control information is communicated between the eNB 207 and the MME unit 204. Multiple MME units 204 may be connected to one eNB 207. The eNBs 207 are connected through the X2 interface, and control information is communicated between the eNBs 207.

[0073] The MME unit 204 is a higher-level device, specifically a higher-level node, and controls the connection between the base station eNB 207 and the mobile terminal (UE) 202. The MME unit 204 constitutes the core network EPC. The base station 203 constitutes the E-UTRAN 201.

[0074] The base station 203 may constitute one cell or a plurality of cells. Each cell has a range predefined as coverage, which is a range within which communication with the mobile terminal 202 is possible, and wireless communication is performed with the mobile terminal 202 within the coverage. When one base station 203 constitutes a plurality of cells, each individual cell is configured to enable communication with the mobile terminal 202.

[0075] FIG. 3 is a block diagram showing the overall configuration of a 5G communication system 210 being discussed in 3GPP. FIG. 3 will be described. The radio access network is referred to as NG-RAN (Next Generation Radio Access Network) 211. The UE 202 is capable of wireless communication with an NR base station device (hereinafter referred to as "NR base station (NG-RAN NodeB: gNB)") 213 and transmits and receives signals through wireless communication. Also, the core network is referred to as 5G Core (5GC).

[0076] If the control protocol for the UE 202, for example, RRC (Radio Resource Control), and the user plane (hereinafter sometimes referred to as U-Plane), for example, SDAP (Service Data Adaptation Protocol), PDCP (Packet Data Convergence Protocol), RLC (Radio Link Control), MAC (Medium Access Control), PHY (Physical layer) are terminated at the NR base station 213, then the NG-RAN is composed of one or a plurality of NR base stations 213.

[0077] The function of the control protocol RRC (Radio Resource Control) between the UE 202 and the NR base station 213 is the same as that of LTE. As the states of the NR base station 213 and the UE 202 in RRC, there are RRC_IDLE, RRC_CONNECTED, and RRC_INACTIVE.

[0078] RRC_IDLE and RRC_CONNECTED are the same as in the LTE mode. While the connection between the 5G core network and the NR base station 213 is maintained, system information (SI) notification, paging, cell re-selection, mobility, etc. are performed in RRC_INACTIVE.

[0079] The gNB 217 is connected to the Access and Mobility Management Function (AMF), Session Management Function (SMF), or User Plane Function (UPF), or an AMF / SMF / UPF unit (hereinafter sometimes referred to as the "5GC unit") 214 including the AMF, SMF, and UPF, via the NG interface. Control information and / or user data are communicated between the gNB 217 and the 5GC unit 214. The NG interface is a general term for the N2 interface between the gNB 217 and the AMF, the N3 interface between the gNB 217 and the UPF, the N11 interface between the AMF and the SMF, and the N4 interface between the UPF and the SMF. For one gNB 217, multiple 5GC units 214 may be connected. The gNBs 217 are connected to each other via the Xn interface, and control information and / or user data are communicated between the gNBs 217.

[0080] Similar to the base station 203, the NR base station 213 may also consist of one or more cells. When one NR base station 213 consists of multiple cells, each cell is configured to be able to communicate with the UE 202.

[0081] gNB 217 may be divided into a Central Unit (hereinafter sometimes referred to as CU) 218 and a Distributed Unit (hereinafter sometimes referred to as DU) 219. One CU 218 is configured within gNB 217. One or more DUs 219 are configured within gNB 217. The CU 218 is connected to the DU 219 via an F1 interface, and control information and / or user data are communicated between the CU 218 and the DU 219.

[0082] The 5G communication system may further include a Unified Data Management (UDM) function and a Policy Control Function (PCF) described in Non-Patent Document 22 (3GPP TS23.501 V16.1.0). The UDM and / or the PCF may be included in the 5GC part in FIG. 3.

[0083] The 5G communication system may further include a Non-3GPP Interworking Function (N3IWF) described in Non-Patent Document 22 (3GPP TS23.501 V16.1.0). The N3IWF may terminate the Access Network (AN) in non-3GPP access with the UE.

[0084] FIG. 4 is a diagram showing the configuration of DC by an eNB and a gNB connected to the EPC. In FIG. 4, the solid line indicates the U-Plane connection, and the dashed line indicates the C-Plane connection. In FIG. 4, eNB 223-1 serves as the master base station, and gNB 224-2 serves as the secondary base station (this DC configuration may sometimes be referred to as EN-DC). In FIG. 4, an example is shown in which the U-Plane connection between the MME part 204 and the gNB 224-2 is made via the eNB 223-1, but it may also be made directly between the MME part 204 and the gNB 224-2.

[0085] FIG. 5 is a diagram showing the configuration of DC by a gNB connected to an NG core. In FIG. 5, solid lines indicate U-Plane connections, and dashed lines indicate C-Plane connections. In FIG. 5, gNB224-1 becomes the master base station, and gNB224-2 becomes the secondary base station (this DC configuration may be referred to as NR-DC). In FIG. 5, an example is shown in which the U-Plane connection between the 5GC unit 214 and gNB224-2 is made via gNB224-1, but it may also be made directly between the 5GC unit 214 and gNB224-2.

[0086] FIG. 6 is a diagram showing the configuration of DC by an eNB and a gNB connected to an NG core. In FIG. 6, solid lines indicate U-Plane connections, and dashed lines indicate C-Plane connections. In FIG. 6, eNB226-1 becomes the master base station, and gNB224-2 becomes the secondary base station (this DC configuration may be referred to as NG-EN-DC). In FIG. 6, an example is shown in which the U-Plane connection between the 5GC unit 214 and gNB224-2 is made via eNB226-1, but it may also be made directly between the 5GC unit 214 and gNB224-2.

[0087] FIG. 7 is a diagram showing another configuration of DC by an eNB and a gNB connected to an NG core. In FIG. 7, solid lines indicate U-Plane connections, and dashed lines indicate C-Plane connections. In FIG. 7, gNB224-1 becomes the master base station, and eNB226-2 becomes the secondary base station (this DC configuration may be referred to as NE-DC). In FIG. 7, an example is shown in which the U-Plane connection between the 5GC unit 214 and eNB226-2 is made via gNB224-1, but it may also be made directly between the 5GC unit 214 and eNB226-2.

[0088] FIG. 8 is a block diagram showing the configuration of the mobile terminal 202 shown in FIG. 2. The transmission process of the mobile terminal 202 shown in FIG. 8 will be described. First, the control data from the protocol processing unit 301 and the user data from the application unit 302 are stored in the transmission data buffer unit 303. The data stored in the transmission data buffer unit 303 is passed to the encoder unit 304, and encoding processing such as error correction is performed. There may be data that is directly output from the transmission data buffer unit 303 to the modulation unit 305 without undergoing encoding processing. The data encoded by the encoder unit 304 is subjected to modulation processing in the modulation unit 305. In the modulation unit 305, precoding in MIMO may be performed. The modulated data is converted into a baseband signal and then output to the frequency conversion unit 306, where it is converted to a radio transmission frequency. Thereafter, transmission signals are transmitted from the antennas 307-1 to 307-4 to the base station 203. In FIG. 8, the case where the number of antennas is four is illustrated, but the number of antennas is not limited to four.

[0089] Also, the reception process of the mobile terminal 202 is executed as follows. The radio signal from the base station 203 is received by the antennas 307-1 to 307-4. The received signal is converted from the radio reception frequency to a baseband signal by the frequency conversion unit 306, and demodulation processing is performed in the demodulation unit 308. In the demodulation unit 308, weight calculation and multiplication processing may be performed. The demodulated data is passed to the decoder unit 309, and decoding processing such as error correction is performed. Among the decoded data, the control data is passed to the protocol processing unit 301, and the user data is passed to the application unit 302. A series of processes of the mobile terminal 202 are controlled by the control unit 310. Therefore, although omitted in FIG. 8, the control unit 310 is connected to each of the units 301 to 309. In FIG. 8, the number of antennas used for transmission and the number of antennas used for reception by the mobile terminal 202 may be the same or different.

[0090] FIG. 9 is a block diagram showing the configuration of the base station 203 shown in FIG. 2. The transmission process of the base station 203 shown in FIG. 9 will be described. The EPC communication unit 401 transmits and receives data between the base station 203 and the EPC (such as the MME unit 204). The 5GC communication unit 412 transmits and receives data between the base station 203 and the 5GC (such as the 5GC unit 214). The other base station communication unit 402 transmits and receives data with other base stations. The EPC communication unit 401, the 5GC communication unit 412, and the other base station communication unit 402 each exchange information with the protocol processing unit 403. The control data from the protocol processing unit 403, as well as the user data and control data from the EPC communication unit 401, the 5GC communication unit 412, and the other base station communication unit 402, are stored in the transmission data buffer unit 404.

[0091] The data stored in the transmission data buffer unit 404 is passed to the encoder unit 405, and encoding processing such as error correction is performed. There may be data that is directly output from the transmission data buffer unit 404 to the modulation unit 406 without undergoing the encoding process. The encoded data is subjected to modulation processing in the modulation unit 406. Precoding in MIMO may be performed in the modulation unit 406. The modulated data is converted into a baseband signal and then output to the frequency conversion unit 407, where it is converted to the radio transmission frequency. Thereafter, a transmission signal is transmitted to one or more mobile terminals 202 from the antennas 408-1 to 408-4. In FIG. 9, the case where the number of antennas is four is illustrated, but the number of antennas is not limited to four.

[0092] Also, the reception processing of the base station 203 is executed as follows. A radio signal from one or more mobile terminals 202 is received by the antenna 408. The received signal is converted from the radio reception frequency to a baseband signal by the frequency conversion unit 407, and demodulation processing is performed by the demodulation unit 409. The demodulated data is passed to the decoder unit 410, and decoding processing such as error correction is performed. Among the decoded data, the control data is passed to the protocol processing unit 403, the 5GC communication unit 412, the EPC communication unit 401, or the other base station communication unit 402, and the user data is passed to the 5GC communication unit 412, the EPC communication unit 401, and the other base station communication unit 402. A series of processes of the base station 203 is controlled by the control unit 411. Therefore, although omitted in FIG. 9, the control unit 411 is connected to each unit 401 to 410. In FIG. 9, the number of antennas used for transmission and the number of antennas used for reception by the base station 203 may be the same or different.

[0093] FIG. 9 is a block diagram showing the configuration of the base station 203, but the base station 213 may have a similar configuration. Also, regarding FIGS. 8 and 9, the number of antennas of the mobile terminal 202 and the number of antennas of the base station 203 may be the same or different.

[0094] FIG. 10 is a block diagram showing the configuration of the MME. FIG. 10 shows the configuration of the MME204a included in the MME unit 204 shown in FIG. 2 described above. The PDN GW communication unit 501 performs data transmission and reception between the MME204a and the PDN GW. The base station communication unit 502 performs data transmission and reception via the S1 interface between the MME204a and the base station 203. When the data received from the PDN GW is user data, the user data is passed from the PDN GW communication unit 501 to the base station communication unit 502 via the user plain communication unit 503 and transmitted to one or more base stations 203. When the data received from the base station 203 is user data, the user data is passed from the base station communication unit 502 to the PDN GW communication unit 501 via the user plain communication unit 503 and transmitted to the PDN GW.

[0095] When the data received from the PDN GW is control data, the control data is passed from the PDN GW communication unit 501 to the control plane control unit 505. When the data received from the base station 203 is control data, the control data is passed from the base station communication unit 502 to the control plane control unit 505.

[0096] The control plane control unit 505 includes an NAS security unit 505-1, an SAE bearer control unit 505-2, an idle state mobility management unit 505-3, etc., and performs overall processing for the control plane (hereinafter, may also be referred to as the C-Plane). The NAS security unit 505-1 performs security of NAS (Non-Access Stratum) messages, etc. The SAE bearer control unit 505-2 performs management of SAE (System Architecture Evolution) bearers, etc. The idle state mobility management unit 505-3 performs mobility management in the standby state (idle state; LTE-IDLE state, or simply referred to as idle), generation and control of paging signals in the standby state, addition, deletion, update, search, and tracking area list management of the tracking area of one or more mobile terminals 202 under its umbrella.

[0097] MME204a distributes paging signals to one or more base stations 203. Also, MME204a performs mobility control in the Idle State. MME204a manages the Tracking Area list when the mobile terminal is in the idle state and in the Active State. MME204a initiates the paging protocol by transmitting a paging message to a cell belonging to the tracking area (Tracking Area) in which the UE is registered. The management of the CSG of the eNB207 connected to MME204a, the management of the CSG ID, and the management of the white list may be performed by the idle state mobility management unit 505-3.

[0098] FIG. 11 is a block diagram showing the configuration of the 5GC. In FIG. 11, the configuration of the 5GC unit 214 shown in FIG. 3 described above is shown. FIG. 11 shows the case where the configuration of the AMF, the configuration of the SMF, and the configuration of the UPF are included in the 5GC unit 214 shown in FIG. 5. The Data Network communication unit 521 transmits and receives data between the 5GC unit 214 and the Data Network. The base station communication unit 522 transmits and receives data via the S1 interface between the 5GC unit 214 and the base station 203 and / or the NG interface between the 5GC unit 214 and the base station 213. If the data received from the Data Network is user data, the user data is passed from the Data Network communication unit 521 to the base station communication unit 522 via the user plain communication unit 523 and transmitted to one or more base stations 203 and / or base stations 213. If the data received from the base station 203 and / or base station 213 is user data, the user data is passed from the base station communication unit 522 to the Data Network communication unit 521 via the user plain communication unit 523 and transmitted to the Data Network.

[0099] When the data received from the Data Network is control data, the control data is passed from the Data Network communication unit 521 to the session management unit 527 via the user plane control unit 523. The session management unit 527 passes the control data to the control plane control unit 525. When the data received from the base station 203 and / or the base station 213 is control data, the control data is passed from the base station communication unit 522 to the control plane control unit 525. The control plane control unit 525 passes the control data to the session management unit 527.

[0100] The control plane control unit 525 includes a NAS security unit 525-1, a PDU session control unit 525-2, an idle state mobility management unit 525-3, etc., and performs overall processing for the control plane (hereinafter, may also be referred to as the C-Plane). The NAS security unit 525-1 performs security of NAS (Non-Access Stratum) messages, etc. The PDU session control unit 525-2 performs management of the PDU session between the mobile terminal 202 and the 5GC unit 214, etc. The idle state mobility management unit 525-3 performs mobility management in the standby state (idle state; RRC_IDLE state, or simply referred to as idle), generation and control of paging signals in the standby state, addition, deletion, update, search, tracking area list management, etc. of the tracking area of one or more mobile terminals 202 under its umbrella.

[0101] The 5GC unit 214 distributes paging signals to one or more base stations 203 and / or base station 213. Also, the 5GC unit 214 performs mobility control in the idle state. When the mobile terminal is in the idle state, the 5GC unit 214 manages the tracking area list in the inactive state and the active state. The 5GC unit 214 initiates the paging protocol by transmitting a paging message to a cell belonging to the tracking area (tracking area) in which the UE is registered.

[0102] Next, an example of a cell search method in a communication system is shown. FIG. 12 is a flowchart showing an overview from cell search to standby operation performed by a communication terminal (UE) in an LTE-based communication system. When the communication terminal starts cell search, in step ST601, it synchronizes slot timing and frame timing using the first synchronization signal (P-SS) and the second synchronization signal (S-SS) transmitted from surrounding base stations.

[0103] The P-SS and S-SS are combined and called the synchronization signal (SS). A synchronization code corresponding one-to-one to the PCI assigned to each cell is assigned to the synchronization signal (SS). 504 types of PCI are being considered. Synchronization is performed using these 504 types of PCI, and the PCI of the synchronized cell is detected (identified).

[0104] Next, for the cell that has been synchronized, in step ST602, a Cell-specific Reference Signal (CRS), which is a reference signal (Reference Signal: RS) transmitted from the base station for each cell, is detected, and the received power of the RS (Reference Signal Received Power: RSRP) is measured. A code corresponding one-to-one with the PCI is used for the reference signal (RS). By correlating with that code, it can be separated from other cells. By deriving the code for the RS of the cell from the PCI specified in step ST601, it becomes possible to detect the RS and measure the received power of the RS.

[0105] Next, in step ST603, from among the one or more cells detected up to step ST602, a cell with the best reception quality of the RS is selected, for example, a cell with the highest received power of the RS, that is, the best cell.

[0106] Next, in step ST604, the PBCH of the best cell is received to obtain the BCCH, which is the broadcast information. The MIB (Master Information Block), which contains cell configuration information, is mapped to the BCCH on the PBCH. Therefore, by receiving the PBCH and obtaining the BCCH, the MIB can be obtained. Examples of the information in the MIB include the DL (downlink) system bandwidth (also called transmission bandwidth configuration: dl-bandwidth), the number of transmission antennas, the SFN (System Frame Number), etc.

[0107] Next, in step ST605, based on the cell configuration information in the MIB, the DL-SCH of the cell is received to obtain SIB (System Information Block) 1 in the broadcast information BCCH. SIB1 contains information related to access to the cell, information related to cell selection, and scheduling information for other SIBs (SIBk; k is an integer greater than or equal to 2). In addition, SIB1 contains the Tracking Area Code (TAC).

[0108] Next, in step ST606, the communication terminal compares the TAC of SIB1 received in step ST605 with the TAC part of the Tracking Area Identity (TAI) in the tracking area list that the communication terminal already has. The tracking area list is also referred to as the TAI list. TAI is identification information for identifying a tracking area and is composed of a Mobile Country Code (MCC), a Mobile Network Code (MNC), and a Tracking Area Code (TAC). MCC is a country code. MNC is a network code. TAC is a code number of the tracking area.

[0109] If, as a result of the comparison in step ST606, the TAC received in step ST605 is the same as the TAC included in the tracking area list, the communication terminal enters the standby operation in the cell. If, upon comparison, the TAC received in step ST605 is not included in the tracking area list, the communication terminal requests a change of the tracking area to perform a Tracking Area Update (TAU) to the core network (Core Network, EPC) including an MME or the like through the cell.

[0110] In the example shown in FIG. 12, an example of the operation from cell search to standby in the LTE system has been shown. In the NR system, in step ST603, in addition to the best cell, the best beam may be selected. Also, in the NR system, in step ST604, beam information, for example, a beam identifier may be acquired. Further, in the NR system, in step ST604, scheduling information of the Remaining Minimum SI (RMSI) may be acquired. In the NR system, in step ST605, it may be assumed that RMSI is received.

[0111] The device that constitutes the core network (hereinafter sometimes referred to as the "core network side device") updates the tracking area list based on the identification number (such as UE-ID) of the communication terminal sent from the communication terminal together with the TAU request signal. The core network side device transmits the updated tracking area list to the communication terminal. The communication terminal rewrites (updates) the TAC list held by the communication terminal based on the received tracking area list. Thereafter, the communication terminal enters the standby operation in the cell.

[0112] Due to the spread of smartphones and tablet terminal devices, traffic by cellular wireless communication has increased explosively, and there is concern about a shortage of radio resources worldwide. In response to this, in order to improve the frequency utilization efficiency, it has been considered to reduce the cell size and proceed with spatial separation.

[0113] In the configuration of a conventional cell, a cell constituted by an eNB has a relatively wide coverage area. Conventionally, cells have been configured to cover a certain area by the relatively wide coverage areas of a plurality of cells constituted by a plurality of eNBs.

[0114] When the cell size is reduced, a cell constituted by an eNB has a coverage area that is narrower than that of a cell constituted by a conventional eNB. Therefore, in order to cover a certain area as in the conventional case, a larger number of small cellsized eNBs are required compared to conventional eNBs.

[0115] In the following description, a cell with a relatively large coverage area, such as a cell constituted by a conventional eNB, is referred to as a "macro cell", and an eNB that constitutes a macro cell is referred to as a "macro eNB". Also, a cell with a relatively small coverage area, such as a small cellized cell, is referred to as a "small cell", and an eNB that constitutes a small cell is referred to as a "small eNB".

[0116] The macro eNB may be, for example, the "Wide Area Base Station" described in Non-Patent Document 7.

[0117] The small eNB may be, for example, a low-power node, a local area node, a hot spot, etc. Also, the small eNB may be a pico eNB that constitutes a pico cell, a femto eNB that constitutes a femto cell, a HeNB, an RRH (Remote Radio Head), an RRU (Remote Radio Unit), an RRE (Remote Radio Equipment), or an RN (Relay Node). Also, the small eNB may be the "Local Area Base Station" or the "Home Base Station" described in Non-Patent Document 7.

[0118] Figure 13 shows an example of the configuration of a cell in NR. In an NR cell, a narrow beam is formed and transmitted while changing the direction. In the example shown in Figure 13, the base station 750 performs transmission and reception with the mobile terminal using the beam 751-1 at a certain time. At other times, the base station 750 performs transmission and reception with the mobile terminal using the beam 751-2. Similarly hereinafter, the base station 750 performs transmission and reception with the mobile terminal using one or a plurality of the beams 751-3 to 751-8. By doing so, the base station 750 constitutes a wide-area cell.

[0119] In Figure 13, an example in which the number of beams used by the base station 750 is 8 is shown, but the number of beams may be different from 8. Also, in the example shown in Figure 13, the number of beams used by the base station 750 simultaneously is 1, but it may be a plurality.

[0120] In 3GPP, for D2D (Device to Device) communication and V2V (Vehicle to Vehicle) communication, a side link (SL) is supported (see Non-Patent Document 1). The SL is defined by the PC5 interface.

[0121] The physical channels used for SL (see Non-Patent Document 1) will be described. The Physical Sidelink Broadcast Channel (PSBCH) carries information related to system synchronization and is transmitted from the UE.

[0122] The Physical Sidelink Discovery Channel (PSDCH) carries sidelink discovery messages from the UE.

[0123] The Physical Sidelink Control Channel (PSCCH) carries control information from the UE for sidelink communication and V2X sidelink communication.

[0124] The Physical Sidelink Shared Channel (PSSCH) carries data from the UE for sidelink communication and V2X sidelink communication.

[0125] The transport channels used for SL (see Non-Patent Document 1) will be described. The Sidelink Broadcast Channel (SL-BCH) has a predetermined transport format and is mapped to the physical channel PSBCH.

[0126] The Sidelink Discovery Channel (SL-DCH) has periodic notification transmissions in a pre-determined format of a fixed size. Also, the SL-DCH supports both UE autonomous resource selection and resource allocation scheduled by the eNB. There is a risk of collision in UE autonomous resource selection, and there is no collision when the UE is allocated individual resources by the eNB. Also, the SL-DCH supports HARQ combining but does not support HARQ feedback. The SL-DCH is mapped to the physical channel PSDCH.

[0127] The Sidelink Shared Channel (SL-SCH) supports notification transmissions. The SL-SCH supports both UE autonomous resource selection and resource allocation scheduled by the eNB. There is a risk of collision in UE autonomous resource selection, and there is no collision when the UE is allocated individual resources by the eNB. Also, the SL-SCH supports HARQ combining but does not support HARQ feedback. Also, the SL-SCH supports dynamic link adaptation by changing the transmission power, modulation, and coding. The SL-SCH is mapped to the physical channel PSSCH.

[0128] The logical channels used for SL (see Non-Patent Document 1) will be described. The Sidelink Broadcast Control Channel (SBCCH) is a sidelink channel for notifying sidelink system information from one UE to other UEs. The SBCCH is mapped to the transport channel SL-BCH.

[0129] The Sidelink Traffic Channel (STCH) is a one-to-many sidelink traffic channel for transmitting user information from one UE to other UEs. The STCH is used only by UEs with sidelink communication capabilities and UEs with V2X sidelink communication capabilities. One-to-one communication between two UEs with sidelink communication capabilities is also realized by the STCH. The STCH is mapped to the SL-SCH, which is a transport channel.

[0130] In 3GPP, it is being considered to support V2X communication also in NR. The study of V2X communication in NR is being advanced based on the LTE system and the LTE-A system, but changes and additions from the LTE system and the LTE-A system are being made in the following points.

[0131] In LTE, SL communication was only broadcast. In NR, as SL communication, in addition to broadcast, support for unicast and groupcast is being considered (see Non-Patent Document 27 (3GPP RP-182111)).

[0132] In unicast communication and groupcast communication, support for HARQ feedback (Ack / Nack), CSI reporting, etc. is being considered.

[0133] In order to support unicast and groupcast in addition to broadcast in SL communication, support for PC5-S signaling is being considered (see Non-Patent Document 21 (TS23.287)). For example, PC5-S signaling is performed to establish a link for implementing SL, that is, PC5 communication. The link is implemented in the V2X layer and is also referred to as a layer 2 link.

[0134] In addition, in SL communication, the support of RRC signaling is under consideration (see Non-Patent Document 21 (TS23.287)). The RRC signaling in SL communication is also referred to as PC5 RRC signaling. For example, it has been proposed to notify the capabilities of UEs between UEs performing PC5 communication, or to notify the settings of the AS layer for performing V2X communication using PC5 communication.

[0135] In 3GPP, the support of SL communication (hereinafter may be referred to as PC5 communication) within an NPN has been proposed. For example, it has been proposed to construct an NPN in an in-plant environment and perform inter-terminal communication using PC5 communication within the NPN (see Non-Patent Document 25 (3GPP S1-191338)). Also, within the NPN of a factory, it has been proposed to operate AGVs (Automated Guided Vehicles) in cooperation using PC5 communication and / or Uu communication between a base station and a terminal (see Non-Patent Document 26 (3GPP S1-191580)). Thus, there is a requirement for PC5 communication within an NPN and / or Uu communication between a base station and a terminal.

[0136] An NPN includes an S-NPN (standalone NPN) and an NS-NPN (non-standalone NPN) using a CAG (Closed Access Group). An S-NPN is an NPN configured without the support of a public network and is identified by a PLMN ID and an NID (Network ID). An NS-NPN is an NPN configured with the support of a public network, and a CAG is used to prevent the connection of unapproved UEs. A CAG is identified by a CAG ID within the range of one PLMN ID. In this specification, unless otherwise specified, the term "NPN" refers to both S-NPN and NS-NPN without distinguishing between them.

[0137] In the prior art, it is not assumed that V2X services are provided within an NPN, and a UE does not recognize which NPN supports services using D2D communication, V2V communication, or V2X communication (these services may hereinafter be referred to as V2X services). For this reason, for example, a problem occurs in that a UE cannot recognize an NPN capable of implementing a desired V2X service, and thus cannot perform the V2X service.

[0138] Conversely, if any V2X service can be implemented in any NPN, any UE can perform V2X services within the NPN. For this reason, in V2X services, a problem occurs in that it becomes impossible to restrict UEs that can access the NPN.

[0139] A method for solving such problems is disclosed.

[0140] The UE is enabled to perform any V2X service in an accessible NPN. The UE enables D2D communication, V2V communication, or V2X communication for any V2X service in an accessible NPN. The UE enables Uu communication and PC5 communication for any V2X service in an accessible NPN. When the UE performs Uu communication and PC5 communication for any V2X service in an accessible NPN, access is permitted or not rejected.

[0141] By doing so, the UE can identify an NPN capable of implementing V2X services.

[0142] However, further problems occur with the method described above. For example, when a UE performs a plurality of V2X services. When the method described above is applied, all V2X services can be implemented within the same NPN. For this reason, for example, even if a plurality of NPNs are constructed within a factory, a problem occurs in that the V2X services supported by each NPN cannot be made different.

[0143] Disclose a method for solving such problems.

[0144] Associate the V2X service with the NPN. It is advisable to set the NPN available for the V2X service. One NPN available for one or more V2X services may be set. One or more NPNs available for one V2X service may be set. Information associating the information of the V2X service with the NPN available for the V2X service may also be used.

[0145] As the V2X service information, an identifier for identifying the V2X service may be used. For example, a PSID (Provider Service Identifier) or an ITS-AID (Intelligent Transport Systems Application Identifier) may be used. As the information of the NPN, in the case of S-NPN, the identifier of the S-NPN may be used, and in the case of NS-NPN, the identifier of the NS-NPN may be used. As the identifier of the S-NPN, a PLMN ID and / or an NID may be used, and as the identifier of the NS-NPN, an identifier of the CAG may be used. As the identifier of the CAG, a CAG-ID and / or a CAG allowed list which is a list of CAG-IDs may be used.

[0146] The information of the NPN available for the V2X service may be stored in the CN (Core Network). Among the CNs, the information of the NPN available for the V2X service may be stored in the UDM (Unified Data Management) or UDR (Unified Data Repository) that manages and records the registration information of the UE, etc. The information of the NPN available for the V2X service may be stored in the PCF (Policy Control Function) that controls the policy, or the AMF (Access and Mobility Management function) that manages access and mobility, or the SMF (Session Management function) that manages the session.

[0147] A node having information of an NPN for which a V2X service is available may notify the UE of the information. For example, if the PCF has information of an NPN for which a V2X service is available, the PCF may notify the UE of the information. The PCF may notify the UE of the information via the AMF. A node having information of an NPN for which a V2X service is available may notify the RAN node (e.g., gNB) of the information. A node having information of an NPN for which a V2X service is available may notify the RAN node of the information via the AMF.

[0148] The AMF may obtain information of an NPN for which a V2X service is available from the UDM or UDR or PCF. The AMF may notify the UDM or UDR or PCF of a message requesting information of an NPN for which a V2X service is available. The UDM or UDR or PCF that has received the request may notify the AMF of the information. The SMF may obtain the information from the AMF. By doing so, each node can obtain information of an NPN for which a V2X service is available and can use the information as needed.

[0149] Information of an NPN for which a V2X service is available may be stored in an OAM (Operations, Administration and Maintenance) having a maintenance management function. The AMF may obtain information of an NPN for which a V2X service is available from the OAM. By doing so, it becomes possible to provide information of an NPN for which a V2X service is available from the OAM to the network node.

[0150] The UE may store the information of the NPN for which the V2X service is available. The information of the NPN for which the V2X service is available may be stored in a (U)SIM ((Universal) Subscriber Identity Module) or a UICC (Universal Integrated Circuit Card). By doing so, the UE can use the information of the NPN for which the V2X service is available as needed.

[0151] The V2X service information and the information of the NPN for which the V2X service is available may be included in the V2X service-related information (hereinafter sometimes referred to as V2X communication-related information). As the V2X service-related information, a V2X policy or V2X parameter, the V2X service information, and the information of the NPN for which it is available may be included. Also, the V2X service information and the V2X parameter of the NPN for which it is available may be included in the V2X policy or V2X parameter. The V2X service-related information may be a V2X policy or V2X parameter including the V2X service information and the V2X parameter of the NPN for which it is available.

[0152] As the V2X policy or V2X parameter, for example, it may be a V2X policy or V2X parameter on Uu (also referred to as on the Uu reference point). For example, it may be the mapping information of the V2X service provided to the UE for V2X communication on Uu.

[0153] The PCF may notify the UE of the V2X service information and the information of the NPN for which the V2X service is available. For example, the PCF may include the V2X service information and the information of the NPN for which the V2X service is available in the V2X service-related information and notify the UE. The PCF may notify the UE via the AMF or RAN node. By doing so, the UE can recognize the V2X service information and the information of the NPN for which the V2X service is available.

[0154] The PCF may notify the RAN node (e.g., gNB) of the V2X service information and the information of the NPN available for the V2X service. For example, the PCF may include the V2X service information and the information of the NPN available for the V2X service in the V2X service-related information and notify the RAN node. The V2X service-related information may be, for example, the QoS parameters of the V2X service.

[0155] The PCF may notify the RAN node via the AMF. Also, the RAN node may obtain the V2X service information and the information of the NPN available for the V2X service from the OAM. By doing so, the RAN node can recognize the V2X service information and the information of the NPN available for the V2X service. The RAN node can recognize the V2X services executable in the NPN supported by the cell. The RAN node can perform scheduling for Uu communication in the V2X services executable in the NPN supported by the cell for the UE by using the V2X service-related information obtained from the PCF.

[0156] The UE may determine the accessible cells by using the V2X service information and the information of the NPN available for the V2X service. To determine the accessible cells, the information regarding the NPN notified by the cell may be used. For example, the UE uses the V2X service information and the information of the NPN available for the V2X service to derive the NPN available for the V2X service to be performed, and collates the derived NPN with the information regarding the accessible NPN notified by the cell. If the derived NPN is included in the information regarding the accessible NPN notified by the cell, the UE determines that it is accessible and accesses the cell. If the derived NPN is not included in the information regarding the accessible NPN notified by the cell, the UE determines that it is inaccessible and does not access the cell. In case of inaccessibility, the UE may reselect an accessible cell.

[0157] Information about the NPN may include information that enables a person to identify the NW. For example, information that enables identification of the PLMN name to which the person subscribes may be used. When the UE receives information that enables identification of the NW, the information may be displayed to the person. For example, the information may be displayed on the display of the UE mounted in a vehicle. The person may make a determination as to whether access to the NPN is possible. As described above, by providing the person with information that enables identification of the NW and enabling the person to recognize the information, the person can make a determination as to whether access to the NPN is possible. Therefore, it is possible to determine whether access to the NPN is possible according to the person's preference.

[0158] The AMF may notify the UE not only of information on the V2X service and the NPNs available for using it, but also of information on adjacent RAN nodes that support the V2X service and the NPNs available for using it. The RAN node may be a gNB or a cell. The AMF may notify the UE of the information on the adjacent RAN node via the RAN node on which the UE camps. The RAN node may notify the UE of information on adjacent RAN nodes that support the V2X service and the NPNs available for using it.

[0159] The AMF may notify the UE of information on the V2X service supported by the adjacent RAN node of the RAN node on which the UE camps and the NPNs available for using it. The AMF may notify the UE of the information on the adjacent RAN node via the RAN node on which the UE camps. The RAN node may notify the UE of information on the V2X service supported by the adjacent RAN node and the NPNs available for using it.

[0160] The RAN node may notify the adjacent RAN node of information on the NPNs supported by the self-node. The information on the NPNs supported by the RAN node may be information on the NPNs supported for each cell. Instead of for each cell, information on the NPNs supported for each carrier frequency may be notified. Alternatively, information on the NPNs supported for each PLMN may be notified. The information may be notified using the base station interface Xn.

[0161] The RAN node may notify the adjacent RAN node of the information on the V2X services supported by itself. The information on the V2X services supported by the RAN node may be the information on the V2X services supported for each cell. Instead of for each cell, the information on the V2X services supported for each carrier frequency may be notified. Alternatively, the information on the V2X services supported for each PLMN may be notified. The information may be notified using the base station interface Xn.

[0162] The RAN node may notify the adjacent RAN node of the information on the V2X services supported by itself and the information on the NPNs where the V2X services are available. The information may be notified for each cell, for each carrier frequency, or for each PLMN. The information may be notified using the base station interface Xn.

[0163] By the RAN node notifying these information to the adjacent RAN node, the notification from the AMF to the UE can be made unnecessary. By eliminating the processing in the core network (CN), the processing load in the CN can be reduced, and the signaling volume between the CN and the RAN can be reduced.

[0164] By doing so, the UE can select and access the RAN nodes where the V2X services are available. Also, the UE will judge that it is impossible to access the RAN nodes that do not support the NPNs where the V2X services are available, and thus will not access. For the NPNs other than the NPNs where the V2X services are available, the V2X services can be made unavailable. In other words, the V2X services available in the NPN can be restricted.

[0165] Figures 14 and 15 are diagrams showing an example of a sequence for performing V2X Uu communication via a self-NPN cell for Embodiment 1. Figures 14 and 15 are connected at the position of the boundary line BL1415. Figures 14 and 15 show the operations of a UE, a RAN node, an AMF, an SMF, a UPF, and a PCF. In step ST1401, the RAN node notifies the UE of NPN-related information. The UE receives the NPN-related information and, in step ST1403, determines whether it can access the RAN node using the received NPN-related information.

[0166] For example, if the identifier of the NPN notified from the RAN node is included in the identifier of the NPN possessed by the self-UE, the UE determines that it can access the RAN node. If it is not included, the UE determines that it cannot access the RAN node. If the UE determines that access is impossible, it may perform a process of reselecting another RAN node. If the UE determines that access is possible, in step ST1406, it notifies the RAN node of the NPN-related information and the V2X capability. In step ST1407, the RAN node notifies the AMF of the NPN-related information and the V2X capability received from the UE.

[0167] The UE may notify the NPN-related information and the V2X capability, for example, by NAS signaling. For example, the UE may include the NPN-related information and the V2X capability in a message for the registration process and notify them. For example, the UE may include the NPN-related information and the V2X capability in a message for the service request process and notify them.

[0168] For the notification of the NPN-related information and the V2X capability, RRC signaling may be used between the UE and the RAN node, for example. When using RRC signaling, for example, the NPN-related information and the V2X capability may be notified during the RRC connection establishment process.

[0169] Regarding the notification of NPN-related information and V2X capabilities, between the RAN node and the AMF, for example, NG signaling may be used. The NG signaling may be N2 signaling.

[0170] In step ST1411, the AMF performs NPN access permission verification for the UE. The AMF uses the NPN-related information notified by the UE to determine whether the UE can access the NW. If the NPN-related information notified by the UE is included in the NPN where the UE is registered, the AMF determines that access is possible. If it is not included, the AMF determines that access is impossible. When the AMF determines that access is impossible, it may notify the UE of an access rejection message. The access rejection message may include reason information. The reason information may be information indicating access rejection due to different NPNs.

[0171] When the AMF determines that the UE can access, it recognizes that the V2X service can be provided using the V2X capabilities received from the UE. The UE may notify V2X service provision request information together with the V2X capabilities. The AMF can recognize that the UE clearly requests the provision of the V2X service.

[0172] In step ST1413, the AMF notifies the PCF of the V2X capabilities received from the UE. For this notification, for example, the Npcf interface may be used, or the UE Policy Control Create Request message may be used.

[0173] The UE may notify the PCF of the V2X policy provisioning request. The UE may include the request in a UE Policy Container for notifying the PCF. The UE may also notify the request to the PCF via the AMF. For the notification from the UE to the AMF, for example, NAS signaling may be used. For example, a UE Policy Provisioning Request message may be used. For the notification from the AMF to the PCF, for example, the Npcf interface may be used, or a UE Policy Control Update message may be used.

[0174] Upon receiving the information from the UE, the PCF performs V2X service authentication using the UE's registration data in step ST1414. The PCF also determines to provide a V2X policy to the UE. The PCF also determines to provide the UE with information on the V2X service and the NPNs available for it. The V2X policy may include V2X parameters. The V2X policy may also include information on the V2X service and the NPNs available for it.

[0175] In step ST1415, the PCF notifies the AMF of the V2X communication-related information. The V2X communication-related information includes information on the V2X service and the NPNs available for it. The V2X communication-related information may include the V2X policy. The V2X policy may include information on the V2X service and the NPNs available for it. The information on the V2X service and the NPNs available for it may be associated with the V2X parameters. Examples of the V2X parameters include QoS parameters for each V2X service. The PCF may notify the AMF of the V2X communication-related information using the UE policy provisioning process. For this notification, for example, the Namf interface may be used, or a Communication N1N2 MessageTransfer message may be used.

[0176] In step ST1416, the AMF notifies the RAN node of the V2X communication-related information received from the PCF. At this time, the AMF may also notify NPN-related information. The NPN-related information may include update information of the list of NPNs to which the UE is permitted to access. N2 signaling may be used for this notification. By doing so, the RAN node can obtain V2X-related information about the UE. By the RAN node obtaining V2X-related information about the UE, the RAN node can perform scheduling for V2X services using Uu communication.

[0177] The AMF may notify the UE of the V2X communication-related information received from the PCF. For example, the AMF may notify the UE of the V2X communication-related information in steps ST1416 and ST1417. In step ST1417, the RAN node notifies the UE of the NPN-related information and the V2X communication-related information. NAS signaling may be used for the notification from the AMF to the UE. UE-specific RRC signaling may be used for the notification from the RAN node to the UE. By doing so, the UE can also obtain V2X communication-related information. Also, the UE can obtain NPN-related information.

[0178] Although it has been shown that the NPN-related information and the V2X communication-related information are notified by the same signaling, they may be notified by different signaling. By using separate signaling, for example, the AMF can notify the NPN-related information without waiting for the V2X policy provisioning process between the AMF and the PCF. By the early notification of the NPN-related information, for example, the update information of the NPN can be applied earlier.

[0179] In step ST1420, in the UE, a V2X service using Uu communication occurs. If the UE is not camped on a cell within an NPN where the V2X service is available, in step ST1422, the UE selects or reselects a cell within an NPN where the V2X service is available. The UE may use the V2X service obtained in step ST1417 and the information of the NPN where it is available for the selection / reselection. By doing so, the UE can implement the desired V2X service within the NPN where the UE is permitted to access.

[0180] In step ST1425, the UE notifies the selected / reselected cell of NPN-related information and V2X capabilities. In step ST1426, the RAN node constituting the cell notifies the AMF of the NPN-related information and V2X capabilities obtained from the UE. By doing so, the AMF can obtain the NPN-related information and V2X capabilities from the UE.

[0181] In step ST1431, the AMF performs NPN access permission verification for the UE. The AMF uses the NPN-related information notified from the UE to determine whether the UE can access the NW. If the AMF determines that the UE can access, in step ST1449, it establishes a PDU session for the V2X service using Uu communication. In step ST1149, the PDU session is established. After the PDU session is established, in steps ST1450 and ST1451, data communication for the V2X service using Uu communication is performed between the UE and the RAN node, and between the RAN node and the UPF.

[0182] The V2X capabilities notified from the UE to the AMF via the RAN node may include that the V2X policy has already been provided to the UE. Alternatively, if the V2X policy has already been provided to the UE, the UE may not notify the AMF of the V2X policy provision request. If the AMF is notified of the information, it may not request the PCF for V2X communication-related information. The V2X communication-related information provision process can be reduced.

[0183] In the examples of FIGS. 14 and 15, it has been shown that the UE performs the access authentication and policy provisioning processes for V2X communication in advance via a RAN node that the UE can access. In contrast, the processing may be performed after the V2X service occurs. The UE and the CN do not have to maintain a useless registration state or connection state. Until the V2X service occurs, the UE and the CN can avoid using the resources required in those states. It becomes possible to improve the resource utilization efficiency.

[0184] When the V2X policy changes, the V2X policy provisioning process to the PCF may be performed again. For example, the V2X policy may be set for each PLMN. When reselecting a cell within an NPN where the V2X service is available, a cell within a different PLMN may be reselected. This may be applied when the NPN is different and thus the PLMN is different. When the PLMN is different, the V2X policy is also different. Since a cell within a different PLMN is reselected, the V2X policy will also change. When the V2X policy changes, the V2X policy provisioning process to the PCF may be performed again.

[0185] By the method disclosed in Embodiment 1, it becomes possible to perform a V2X service using Uu communication in an NPN. The UE can access an NPN where the V2X service is available, while being unable to access an NPN where the V2X service is unavailable. The V2X services available in the NPN can be restricted. Also, it becomes possible to perform Uu communication for V2X services that can be supported for each NPN, and to prevent Uu communication for V2X services that cannot be supported for each NPN.

[0186] Modification Example 1 of Embodiment 1. In this Modification Example 1, a method for performing a V2X service using device-to-device communication such as D2D communication or V2V communication (hereinafter may be referred to as PC5 communication) in an NPN will be disclosed.

[0187] In addition to the V2X service using Uu communication between the base station and the terminal, in the V2X service using PC5 communication between terminals, the UE may implement a plurality of V2X services. In such a case, the problems as disclosed in Embodiment 1 also occur. For example, even if a plurality of NPNs are constructed in a factory, there is a problem that the V2X services using PC5 communication supported by each NPN cannot be made different.

[0188] Regarding such problems in the V2X service using PC5 communication, the method of associating the V2X service and the NPN disclosed in Embodiment 1 may also be applied. It is advisable to set an NPN available for the V2X service. One NPN available for one or more V2X services may be set. One or more NPNs available for one V2X service may be set. Information associating the information of the V2X service and the NPN available for the V2X service may also be used.

[0189] In Embodiment 1, the V2X service using Uu communication was disclosed in the sequence examples of FIGS. 14 and 15. In contrast, in this Modification Example 1, the V2X service using PC5 communication is disclosed.

[0190] The scheduling for PC5 communication for the UE is performed by the base station within the NPN accessible by the UE performing the PC5 communication. As a method of PC5 communication, there is a method in which the base station performs scheduling (hereinafter, may be referred to as Mode 1). When implementing the V2X service using the PC5 communication of Mode 1, this Modification Example 1 may be applied.

[0191] As a method for implementing a V2X service using PC5 communication, the method disclosed in Embodiment 1 may be appropriately applied. For example, a method for setting an NPN available for the V2X service, a method for including V2X service information and information on the NPN available for the V2X service in V2X service-related information, a method for notifying the UE from the PCF of the V2X service information and the information on the NPN available for the V2X service, a method for notifying the RAN node (e.g., gNB) from the PCF of the V2X service information and the information on the NPN available for the V2X service, a method for the UE to determine an accessible cell using the V2X service information and the information on the NPN available for the V2X service, etc. may be appropriately applied. The V2X service-related information may be, for example, a V2X policy or V2X parameters on PC5 (also referred to as on the PC5 reference point).

[0192] The V2X service-related information may be separated into information related to Uu communication and information related to PC5 communication. For example, in the method for setting an NPN available for the V2X service, the information on the NPN available for the V2X service using Uu communication and the information on the NPN available for the V2X service using PC5 communication may be separated. In Embodiment 1, the information on the NPN available for the V2X service using Uu communication may be used. In this Modification Example 1, the information on the NPN available for the V2X service using PC5 communication may be used. By doing so, the amount of information on the NPN available for the V2X service to be used can be reduced.

[0193] The RAN node may perform NPN access availability verification. The RAN node performs NPN access availability verification for the UE. The RAN node may perform NPN access availability verification when providing V2X services using PC5 communication. The RAN node verifies the availability of access to the NPN of its own cell for access to V2X services from the UE. If access is available, the RAN node permits access to the UE and performs scheduling for PC5 communication. If access is not possible, the RAN node does not permit access to the UE. The RAN node may notify the UE of the rejection. The RAN node may include reason information in the rejection and notify the UE.

[0194] The RAN node that performs NPN access availability verification for the UE may be the RAN node under the AMF to which the UE is connected. The RAN node may recognize in advance the association between V2X services and the NPNs available for them. The RAN node may perform NPN access availability verification only when it has recognized in advance the association between V2X services and the NPNs available for them. The RAN node may determine whether to perform NPN access availability verification for the UE according to whether it recognizes the association between V2X services and NPNs for access to V2X services from the UE. If the RAN node recognizes the association, it performs NPN access availability verification. If the RAN node does not recognize the association, it does not perform NPN access availability verification, notifies the AMF, and the AMF performs NPN access availability verification for the UE.

[0195] For example, when a UE provides a V2X service using PC5 communication, communication with the CN may not be necessary. For example, this may be the case when the UE and / or the RAN node already have obtained V2X authentication and are provided with a V2X policy. In such a case, it is possible to eliminate the need for the AMF to verify the NPN access permission. By performing the NPN access permission verification at the RAN node, the signaling between the CN and the RAN node can be reduced. Also, it becomes possible to provide the V2X service with lower latency than when performing the NPN access permission verification at the AMF.

[0196] FIGS. 16 and 17 are diagrams showing an example of a sequence for performing V2X PC5 communication via a self-NPN cell for Modification Example 1 of Embodiment 1. FIGS. 16 and 17 are connected at the position of a boundary line BL1617. FIGS. 16 and 17 show an example in which a RAN node (base station) performs PC5 communication scheduling for a UE. FIGS. 16 and 17 show the operations of a transmitting UE, a receiving UE, a RAN node, an AMF, an SMF, a UPF, and a PCF. The transmitting UE and the receiving UE are UEs that perform PC5 communication. PC5 communication is performed between the transmitting UE and the receiving UE. The transmitting UE transmits data for a V2X service, and the receiving UE receives the data for the V2X service transmitted from the transmitting UE. In FIGS. 16 and 17, steps common to FIGS. 14 and 15 are denoted by the same step numbers, and the common descriptions are omitted.

[0197] In step ST1502, the RAN node notifies the UE of NPN-related information. The transmitting UE receives the NPN-related information and, in step ST1504, determines whether it can access the RAN node using the received NPN-related information. The receiving UE may receive the NPN-related information notified by the RAN node. The methods disclosed in FIGS. 14 and 15 may be applied to determine whether access is possible for the transmitting UE. If the transmitting UE determines that access is possible, in step ST1406, it notifies the RAN node of the NPN-related information and the V2X capability. In the examples of FIGS. 16 and 17, the PC5 communication capability may be used as the V2X capability. The V2X capability may include information indicating that PC5 communication is possible.

[0198] Note that the V2X capability in FIGS. 14 and 15 of Embodiment 1 may be the Uu communication capability. By doing so, the NW-side node can recognize whether the UE has the Uu communication capability or the PC5 communication capability as V2X communication. Also, by the UE notifying these capabilities to the NW side, the NW-side node can recognize whether to request authentication of Uu communication and provision of policies or parameters, or authentication of PC5 communication and provision of policies or parameters.

[0199] In step ST1411, when the AMF determines that the transmitting UE can access, it recognizes that it can provide the V2X service using the V2X capability received from the transmitting UE. When the PC5 communication capability is notified, the AMF can clearly recognize that it can provide the V2X service using PC5 communication. The transmitting UE may notify the V2X service provision request information together with the V2X capability. V2X service provision request information using Uu communication and V2X service provision request information using PC5 communication may be provided. By the transmitting UE notifying the V2X service provision request information using PC5 communication, the AMF can recognize that the transmitting UE clearly requests the provision of the V2X service using PC5 communication.

[0200] In step ST1413, the AMF notifies the PCF of the V2X capabilities received from the transmitting UE. For this notification, for example, the Npcf interface may be used, or the UE Policy Control Create Request message may be used.

[0201] The transmitting UE may notify the PCF of a V2X policy provision request. The transmitting UE may include the request in a UE Policy Container for notifying the PCF and then notify it. The transmitting UE may also notify the PCF via the AMF. For the notification from the transmitting UE to the AMF, for example, NAS signaling may be used. For example, the transmitting UE Policy Provision Request message may be used. For the notification from the AMF to the PCF, for example, the Npcf interface may be used, or the UE Policy Control Update message may be used.

[0202] In step ST1414, the PCF that has received the information from the transmitting UE performs V2X service authentication using the registration data of the transmitting UE. The PCF may perform authentication of the V2X service using PC5 communication. Also, the PCF determines to provide a V2X policy to the transmitting UE. The PCF may determine to provide a V2X policy using PC5 communication. Also, the PCF determines to provide the transmitting UE with information on the V2X service and the NPNs available for it. The PCF may determine to provide information on the V2X service using PC5 communication and the NPNs available for it. Not only the V2X policy but also the V2X policy or V2X parameters may be included. The V2X service and the information on the NPNs available for it may be included in the V2X policy or V2X parameters.

[0203] In step ST1415, the PCF notifies the AMF of V2X communication-related information. The V2X service notified as the V2X communication-related information may be a V2X service using PC5 communication.

[0204] In step ST1521, in the transmitting UE, a V2X service using PC5 communication occurs. If the transmitting UE is not camped on a cell within an NPN where the V2X service is available, in step ST1523, the UE selects or reselects a cell within an NPN where the V2X service is available. The transmitting UE may use the V2X service obtained in step ST1417 and the information of the NPN where it is available for the selection / reselection. By doing so, the transmitting UE can implement the desired V2X service within the NPN permitted for the transmitting UE to access.

[0205]

[0204] In step ST1530, the transmitting UE notifies the selected / reselected cell of NPN-related information and V2X capabilities. In FIGS. 16 and 17, in step ST1532, an example is disclosed in which a RAN node constituting the cell performs NPN access permission verification for the transmitting UE. The RAN node determines whether the transmitting UE can access the self-RAN node using the NPN-related information notified from the transmitting UE. If the RAN node determines that the transmitting UE is accessible, in step ST1533, the RAN node may notify the transmitting UE of a V2X service permission message using PC5 communication.

[0206] In this way, when the RAN node performs NPN access permission verification, when a UE having information of an NPN where a V2X service using PC5 communication is available performs PC5 communication, access to the core network side becomes unnecessary. It becomes possible to reduce the time until the start of PC5 communication.

[0207] If the RAN node reselected by the transmitting UE in step ST1523 is different from the RAN node that received the V2X communication-related information in step ST1416, the RAN node may request the AMF or the PCF to provide V2X-related information. The processing from step ST1407 to step ST1416 may be performed. The RAN node can obtain the V2X-related information for the transmitting UE. Also, in this case, the AMF may perform the NPN access permission verification for the UE.

[0208] The transmitting UE notifies the RAN node of the BSR in step ST1534. The transmitting UE may also notify an SR (Scheduling Request). The RAN node that receives the BSR performs scheduling for PC5 communication for the transmitting UE in step ST1535. The RAN node may perform scheduling for PC5 communication using the V2X communication-related information received in step ST1416.

[0209] The transmitting UE uses the PC5 communication scheduling information received from the RAN node in step ST1535 to perform PC5-S signaling with the receiving UE in step ST1547 and establish a link for PC5 communication. In step ST1548, the transmitting UE performs RRC signaling with the receiving UE and mutually notifies, for example, the AS layer configuration information and UE capability information. By doing so, both the transmitting UE and the receiving UE can set the AS layer for PC5 communication. The order of the PC5-S signaling and the RRC signaling may be appropriately interchanged. For example, the RRC signaling required for performing the PC5-S signaling may be performed before the PC5-S signaling. For example, a link for PC5 communication may be established by performing RRC signaling and then performing PC5-S signaling.

[0210] In step ST1552, data communication of the V2X service using PC5 communication is performed between the transmitting UE and the receiving UE. In PC5 communication, the transmitting UE may transmit the BSR to the RAN node multiple times. The BSR may be appropriately transmitted from PC5-S signaling until V2X service data transmission or until PC5 link release. The RAN node performs scheduling for PC5 communication upon receiving the BSR, and notifies the transmitting UE of the scheduling information for PC5 communication. By doing so, the RAN node belonging to the NPN capable of providing the V2X service using PC5 communication can perform PC5 communication scheduling for the UE.

[0211] By the method disclosed in the first modification example 1 of the first embodiment, it becomes possible to perform the V2X service using PC5 communication in the NPN. The UE can access the NPN where the V2X service is available, while being unable to access the NPN where the V2X service is unavailable. The V2X service available in the NPN can be restricted. Also, it becomes possible to perform PC5 communication of the V2X service supportable for each NPN. It becomes possible to prevent PC5 communication of the V2X service not supportable for each NPN from being performed.

[0212] Modification example 2 of the first embodiment. In this second modification example, another method for solving the problems disclosed in the first modification example 1 of the first embodiment is disclosed.

[0213] When the UE performing PC5 communication exists within the coverage of the base station in the accessible NPN, scheduling for PC5 communication between the opposing UEs is performed. As a method of PC5 communication, there is a method in which the transmitting UE performing PC5 communication performs scheduling (hereinafter may be referred to as mode 2). When implementing the V2X service using PC5 communication in mode 2, this second modification example may be applied.

[0214] Resources used for PC5 communication scheduling (hereinafter sometimes referred to as PC5 communication resources) are notified, for example, from a base station within an NPN accessible to the UE. As the PC5 communication resources, a resource pool (RP) may be notified. The PC5 communication resources may be pre-configured in the UE. When the resources used for scheduling are pre-configured in the UE, the resources may be updated by the PCF. The update of the resources may be provided from the PCF to the UE using the V2X service policy (V2X policy) provisioning process.

[0215] The RAN node may notify the UE of information associating the PC5 communication resources with the NPN in which the resources are available. The RAN node may include the information in the system information and notify it. Alternatively, the RAN node may notify the information in the system information by individual signaling. The RAN node may notify the information using a shared channel.

[0216] The RAN node may include the information regarding the PC5 communication resources in the information regarding the NPN notified to the UE and notify it. The RAN node may notify the information associating the NPN with the PC5 communication resources. UEs that require NPN access control can recognize the PC5 communication resources required for V2X services by obtaining the information. Alternatively, the RAN node may include the information regarding the NPN using the resources in the information regarding the PC5 communication resources notified to the UE and notify it. UEs that implement V2X services by PC5 communication can recognize the NPNs capable of implementing V2X services by obtaining the information regarding the PC5 communication resources.

[0217] The UE may acquire in advance the V2X service information using PC5 communication and the information of the NPN available for the V2X service. For the UE performing the V2X service using PC5 communication, both the transmitting UE and the receiving UE may acquire in advance the V2X service information and the information of the NPN available for the V2X service. The method disclosed in Embodiment 1 or Modification Example 1 of Embodiment 1 may be appropriately applied. For example, a method of notifying the UE from the PCF of the V2X service information and the information of the NPN available for the V2X service may be applied.

[0218] The UE may store in advance the V2X service information using PC5 communication and the information of the NPN available for the V2X service. The method disclosed in Embodiment 1 may be appropriately applied.

[0219] The transmitting UE performing the V2X service using PC5 communication may verify whether it is possible to perform the V2X service using PC5 communication within the NPN by using the information on the NPN associated with the V2X service using PC5 communication acquired in advance and the information on the NPN notified from the RAN node. If the information on the NPN is the same, the transmitting UE determines that PC5 communication is possible and activates PC5 communication using the PC5 communication resource associated with the NPN. If the information on the NPN is different, the transmitting UE determines that PC5 communication is not possible and does not activate PC5 communication. The transmitting UE may request the RAN node for the PC5 communication resource again.

[0220] By doing so, when the transmitting UE performs the V2X service using PC5 communication, it becomes possible to perform the NPN access availability verification. Through the NPN access availability verification, it becomes possible to make the V2X service impossible for a UE that cannot access the NPN available for the V2X service using PC5 communication. It is possible to implement the NPN access restriction also in the V2X service using PC5 communication.

[0221] The receiving UE derives the PC5 communication resource used for the V2X service by using the information about the NPN associated with the V2X service using PC5 communication obtained in advance and the information about the NPN notified from the RAN node and the PC5 communication resource information corresponding to the NPN. The receiving UE performs reception processing for PC5 communication using the derived PC5 communication resource. As a result, the receiving UE can receive PC5 communication from the transmitting UE.

[0222] The RP may be set for each V2X service. Alternatively, the RP may be divided and set for each V2X service. One RP may be divided into a plurality of sub-RPs for setting. The RP used in the NPN may be set for each NPN. Alternatively, the RP may be divided and set for each NPN. One RP may be divided into a plurality of sub-RPs for setting. One RP or sub-RP may be used in one or more NPNs. The NPN and the RP used in the NPN may be associated with each other. The PC5 communication within the same NPN may be performed using the associated RP.

[0223] These may be combined, enabling the setting of the V2X service, the NPNs available for it, and the RPs used in those NPNs. Although the RP has been disclosed, the RP is merely an example of the PC5 communication resource. The PC5 communication resource may be the frequency used for PC5 communication. The PC5 communication resource is not limited to the frequency and may also be a bandwidth.

[0224] These setting information may be provided from the CN to the UE. For example, the PCF notifies the UE of these setting information. The PCF may include these setting information in the V2X-related information and then notify it. For example, the PCF may notify these setting information by using the V2X policy providing process. As these methods, the methods disclosed in Modification Example 1 of Embodiment 1 may be applied. These setting information may be configured in the CN-side node. As the method of configuring in the CN-side node, the methods disclosed in Embodiment 1 may be appropriately applied.

[0225] By doing so, it becomes possible to configure the PC5 communication resources used for each V2X service or for each NPN. Since it is possible to separate the resources used for PC5 communication for each V2X service or for each NPN, a V2X service using PC5 communication can be implemented without being interfered with by other V2X services or other NPNs, such as collisions with communication in other V2X services or other NPNs.

[0226] The transmitting UE may notify the receiving UE of V2X service information using PC5 communication and information on the NPN in which the V2X service is available. Alternatively, the transmitting UE may notify any one of the information. The information regarding the NPN may be an identifier for identifying the NPN. By doing so, the receiving UE can receive these information from the transmitting UE without receiving them from the RAN node. The receiving UE can execute a V2X service using PC5 communication with the transmitting UE.

[0227] The receiving UE compares the information on the NPN associated with the V2X service, which has been acquired in advance, with the V2X service information using PC5 communication and the information on the NPN in which the V2X service is available, notified from the transmitting UE, and may verify whether it is possible to implement the V2X service using PC5 communication within the transmitting UE and the NPN. If the information regarding the NPN is the same, the receiving UE determines that PC5 communication is possible. Also, the receiving UE receives a V2X service from the transmitting UE using the PC5 communication resources associated with the NPN. If the information regarding the NPN is different, the receiving UE determines that PC5 communication is not possible and does not receive the V2X service.

[0228] FIG. 18 and FIG. 19 are diagrams showing an example of a sequence for performing V2X PC5 communication via its own NPN cell for Modification Example 2 of Embodiment 1. FIG. 18 and FIG. 19 are connected at the position of the boundary line BL1819. FIG. 18 and FIG. 19 show an example in which the UE performs scheduling of PC5 communication. In FIG. 18 and FIG. 19, the same step numbers are assigned to the steps common to FIG. 16 and FIG. 17, and the common descriptions are omitted.

[0229] In step ST1521, in the transmitting UE, a V2X service using PC5 communication occurs. In step ST1523, the transmitting UE reselects a cell within the NPN where the V2X service is available. In step ST1629, the transmitting UE receives PC5 communication-related information notified from the reselected cell. The PC5 communication-related information may include information regarding a resource pool (RP) for PC5 communication. Further, the PC5 communication-related information may include information regarding the NPN, such as an identifier. The RP may be associated with information regarding the NPN.

[0230] By doing so, the transmitting UE can acquire resources for performing PC5 communication scheduling. Also, the transmitting UE can acquire information regarding the NPN where the V2X service using PC5 communication is available.

[0231] In the examples of FIGS. 18 and 19, in step ST1637, the transmitting UE performs NPN access availability verification. The transmitting UE can recognize an RP corresponding to the NPN where the generated V2X service using PC5 communication is available by using the PC5 communication-related information notified from the RAN node and the V2X communication-related information notified in step ST1417. In step ST1638, the transmitting UE selects an RP corresponding to the NPN where the V2X service is available. The transmitting UE performs scheduling for PC5 communication by using the selected RP.

[0232] If there is no RP corresponding to the NPN that can utilize the V2X service using the generated PC5 communication, the transmitting UE determines that PC5 communication is impossible and does not perform PC5 communication. In that case, for example, the transmitting UE may request the AMF or the PCF again to provide V2X communication related information. For example, the transmitting UE may perform the processing from step ST1407 to step ST1417. The transmitting UE may perform the processing via the cell reselected at step ST1523. The transmitting UE reselects a cell within the NPN that can utilize the V2X service again, and verifies whether NPN access is possible using the PC5 communication related information notified from the cell.

[0233] In this way, when the transmitting UE performs the NPN access availability verification, when a UE having information on the NPN that can utilize the V2X service using PC5 communication performs PC5 communication, access to the network side becomes unnecessary. It becomes possible to further reduce the time until the start of PC5 communication.

[0234] The transmitting UE makes a PC5 communication request to the receiving UE at step ST1642. The transmitting UE may perform the request by PC5-S signaling. The PC5 communication request may include NPN related information. The receiving UE can recognize the NPN related information. The receiving UE may transmit a PC5 communication permission to the transmitting UE at step ST1645. The receiving UE may include NPN related information in the PC5 communication permission. The transmitting UE can confirm the NPN of the V2X service using the PC5 communication to be performed with the receiving UE.

[0235] The receiving UE may also perform the processes from step ST1502 to step ST1417, similar to the transmitting UE. The receiving UE may perform NPN access availability verification. For example, the receiving UE may perform the process of step ST1629. Thereby, the receiving UE can confirm whether the NPN supports the received V2X service by using the NPN-related information notified by the transmitting UE in step ST1642. If the NPN supports the received V2X service, the receiving UE may notify PC5 communication permission in step ST1645, and if not, may notify PC5 communication rejection. Alternatively, the receiving UE may not transmit anything. By doing so, the desired V2X service can be implemented only in an NPN that can utilize the desired V2X service using PC5 communication. Also, a UE different from the UE that performs NPN access availability determination can perform NPN access availability verification.

[0236] If the RAN node reselected by the transmitting UE in step ST1523 is different from the RAN node that received the V2X communication-related information in step ST1416, the RAN node may request the AMF or PCF to provide V2X-related information. The processes from step ST1407 to step ST1416 may be performed. The RAN node can obtain the V2X-related information for the transmitting UE. Also, in this case, the AMF may perform NPN access availability verification for the UE.

[0237] In this Modification Example 2, an example in which the RAN node notifies PC5 communication-related information is disclosed. Even when the UE performing PC5 communication moves outside the coverage of the RAN node, the UE may implement the V2X service using PC5 communication by using the PC5 communication-related information received when it was within the coverage. The V2X service using PC5 communication can be implemented even outside the coverage of the RAN node.

[0238] By the method disclosed in Modification Example 2 of Embodiment 1, it becomes possible to implement a V2X service using PC5 communication with NPN. Even when a transmitting UE performing PC5 communication performs PC5 communication scheduling, it becomes possible to implement a V2X service using PC5 communication within the NPN. Also, NPN access restriction can be implemented even in a V2X service using PC5 communication. Also, since it is not necessary to access the RAN node for PC5 communication scheduling, PC5 communication can be implemented with low latency.

[0239] Modification Example 3 of Embodiment 1. As a method of PC5 communication, there is a method in which a transmitting UE performing PC5 communication performs scheduling. The PC5 communication resource may be configured in the UE in advance. When performing PC5 communication using the PC5 communication resource configured in the UE in advance, access from the UE to the NW side is not required. For example, even when the UE does not exist within the coverage of the cell belonging to its own NPN, the UE can perform PC5 communication.

[0240] However, in a conventional NPN, the UE determines whether access is possible based on the information received from the cell, and the AMF performs access permission verification by the UE accessing the AMF via the cell. Therefore, when the UE cannot find a cell belonging to its own NPN, access control cannot be implemented, the UE cannot determine whether PC5 communication is possible, and PC5 communication becomes impossible.

[0241] This modification example 3 discloses a method for solving such problems.

[0242] Even when the UE does not use a cell belonging to its own NPN as a serving cell, PC5 communication can be executed. A V2X service using PC5 communication can be implemented. Even if the UE is set to be able to communicate only with its own CAG, PC5 communication may be executable outside its own CAG. A V2X service using PC5 communication can be implemented.

[0243] The UE determines whether the V2X service to be implemented is a V2X service using PC5 communication with PC5 communication resources pre-configured in the UE. In the case of a V2X service using PC5 communication with PC5 communication resources pre-configured in the UE, and if the UE does not use the cell belonging to its own NPN as the serving cell, the UE implements the V2X service. If it is not a V2X service using PC5 communication with PC5 communication resources pre-configured in the UE, and if the UE does not use the cell belonging to its own NPN as the serving cell, the UE does not implement the V2X service. For example, if there are no PC5 communication resources for the V2X service using PC5 communication, and if the UE does not use the cell belonging to its own NPN as the serving cell, it may be assumed that the V2X service is not implemented.

[0244] By doing so, the UE can execute PC5 communication even when it does not use the cell belonging to its own NPN as the serving cell.

[0245] Information indicating whether PC5 communication is possible outside the cell belonging to the own NPN for PC5 communication may be provided. This information may be included in V2X-related information, may be included in V2X capabilities, or may be included in NPN-related information. This information may be pre-configured in the UE. This information may be stored in the UE. This information may be stored in the USIM or CICC.

[0246] The information indicating whether PC5 communication is possible outside the cell belonging to the own NPN for PC5 communication may be provided by the PCF or updated when the UE becomes accessible to the CN. This information may be provided using the process of providing V2X-related information from the PCF to the UE. For example, this information may be provided using the process of providing V2X policies.

[0247] The UE may determine whether the V2X service to be implemented is a V2X service using PC5 communication with PC5 communication resources pre-configured in the UE by using information indicating whether PC5 communication is possible outside the cell belonging to its NPN. The UE can control whether PC5 communication is possible outside the cell belonging to its NPN.

[0248] It may be determined in advance statically by standards or the like that PC5 communication can be executed even when the UE does not use the cell belonging to its NPN as the serving cell. It may be determined in advance statically by standards or the like that a V2X service using PC5 communication can be implemented even when the UE does not use the cell belonging to its NPN as the serving cell. In these examples, instead of the case where the UE does not use the cell belonging to its NPN as the serving cell, the case where the UE cannot find the cell belonging to its NPN, the case where the UE cannot find the cell where the information of its NPN is notified, or the case where the UE that requests access to the NW receives a rejection for the access request because it is not its NPN may be applied. Note that the access request may be made, for example, by a registration request or a service request.

[0249] By doing so, a large number of UEs implementing V2X services using PC5 communication can execute PC5 communication even when it is clear that they do not use the cell belonging to their NPN as the serving cell. It is possible to reduce malfunction in communication between UEs.

[0250] As described above, the PC5 communication resources used when cells belonging to the self-NPN are not serving cells may be configured in advance in the UE. This is applicable when the PC5 communication resource information is not notified from the PCF to the UE. As another example, the resources used for PC5 communication may be the PC5 communication resources provided most recently from the CN. This is applicable when the UE can access the CN. For example, when the UE is in a state of being present in the coverage area of a cell belonging to the self-NPN in advance, the UE receives V2X service authentication and V2X policy provision for the V2X service via the self-NPN cell and acquires the PC5 communication resources. By using the PC5 communication resources provided from the CN side in this way, PC5 communication can be executed even outside the self-NPN.

[0251] An expiration date may be set for the PC5 communication resources. Within the expiration date, the PC5 communication resources can be used, and when the expiration date is exceeded, the PC5 communication resources cannot be used. The expiration date may be managed by a timer. The expiration date information (which may be timer information) may be determined statically by a standard or the like, or may be configured in advance in the UE. Alternatively, the expiration date information (which may be timer information) may be provided from the CN when the UE can access the CN. By doing so, the UE can recognize the PC5 communication resources that can be used when cells belonging to the self-NPN are not serving cells.

[0252] The PC5 communication resources used for V2X services may be set for each V2X service. PC5 communication resources that can be used in a predetermined area may be set. The predetermined area may be set in advance. The PC5 communication resources used in the NPN may be set for each NPN. These may be combined. The PC5 communication resources may be RPs. They may be one or more RPs. These setting information may be stored in the UE. These setting information may be provided by the CN when the UE can access the CN. For example, the PCF notifies the UE of these setting information. The setting information may be notified included in the V2X related information. For example, the setting information may be notified using the V2X policy providing process. As these methods, the method disclosed in Modification Example 2 of Embodiment 1 may be applied.

[0253] When the UE does not use the cell belonging to its own NPN as the serving cell and performs PC5 communication between UEs, the conventional NPN access control of Uu communication cannot be used, and problems occur such as the inability to perform NPN access control such as the UE's determination of whether NPN access is possible and the AMF's verification of whether access is possible. Also, for this reason, a problem occurs in that the UE that executes PC5 communication communicates with a UE outside its own NPN. A method for solving such problems is disclosed.

[0254] The transmitting UE of PC5 communication notifies the receiving UE of its own NPN related information. The NPN related information may be an identifier for specifying the NPN.

[0255] A method for notifying NPN related information between UEs is disclosed. The NPN related information may be notified at the V2X application layer. For example, the transmitting UE notifies the receiving UE of the NPN related information as signaling or data at the V2X application layer. The NPN related information may be notified together with the V2X service information.

[0256] As another method, the NPN-related information may be notified at the V2X layer. The NPN-related information may be notified by PC5-S signaling. The NPN-related information may be notified when establishing a layer 2 link for PC5 communication between UEs. For example, the transmitting UE may include the NPN-related information in a Direct Communication Request and notify the receiving UE. The V2X layer converts V2X service information into a layer 2 identifier. The NPN-related information may be notified together with the layer 2 identifier. Information regarding the mapping between the V2X service information and the layer 2 identifier may be provided by the CN to the UE in advance. Alternatively, this information may be pre-configured in the UE.

[0257] As another method, the NPN-related information may be notified at the AS layer. The NPN-related information may be notified by RRC signaling. The NPN-related information may be notified when establishing an RRC link for PC5 communication between UEs. For example, the transmitting UE may include the NPN-related information in a UE capability inquiry notification or a UE capability information notification and notify the receiving UE. For example, the transmitting UE may include the NPN-related information in a Configuration Message notification for PC5 communication or a notification of completion of PC5 communication configuration and notify the receiving UE.

[0258] Another notification method at the AS layer is disclosed. The NPN-related information may be notified in a Synchronization procedure. The NPN-related information may be included, for example, in the PSBCH or in the SL-BCH and notified. As another method, the NPN-related information may be notified in a Discovery procedure. The NPN-related information may be included, for example, in the PSDCH and notified. As another method, the NPN-related information may be notified in PC5 communication. The NPN-related information may be included, for example, in the PSSCH or in the SL-SCH and notified. Also, the NPN-related information may be included, for example, in the PSCCH or in the SCI and notified.

[0259] By doing so, it becomes possible to notify NPN-related information among UEs performing PC5 communication.

[0260] The V2X service may be associated with an NPN capable of using it. The V2X service may be associated with the NPN (which may also be referred to as the own NPN) to which the own UE in the NPN capable of using it belongs. By associating the V2X service with the NPN to which the own UE in the NPN capable of using it belongs, when the V2X service is supported by a plurality of different NPNs, it becomes possible to associate it with a specific NPN among the NPNs. The specific NPN can be the NPN to which the own UE belongs. The NPN to which the own UE belongs may be one or plural.

[0261] Among UEs performing PC5 communication, information associating the V2X service with the own NPN capable of using it may be notified. The transmitting UE of the PC5 communication may notify the receiving UE of information associating the V2X service with the own NPN capable of using it.

[0262] A method of associating a V2X service with the own NPN capable of using it is disclosed.

[0263] Associate V2X service information with NPN-related information. It is preferable to set an NPN capable of using the V2X service. One NPN capable of using one or a plurality of V2X services may be set. One or a plurality of NPNs capable of using one V2X service may be set. Information associating the information of the V2X service with the information of the NPN capable of using the V2X service may also be used.

[0264] For example, an identifier for specifying a V2X service is associated with an identifier for specifying an NPN. This association may be performed in the V2X application layer. This is effective when the V2X application layer recognizes the correspondence between the V2X service and the NPN available for it. Information on the association between the V2X service and the NPN available for it may be notified between UEs as signaling or data in the above-mentioned V2X application layer.

[0265] Another method is disclosed. The V2X application layer notifies the V2X layer of the association information between the V2X service and the NPN available for it. This is effective when the V2X application layer recognizes the correspondence between the V2X service and the NPN available for it. Alternatively, the V2X layer may associate the V2X service with the NPN available for it. This is effective when the V2X layer recognizes the association between the V2X service and the NPN available for it.

[0266] Since the V2X service information is converted into a layer 2 identifier in the V2X layer, it is advisable to associate this layer 2 identifier with the NPN-related information. The layer 2 identifier may be a layer 2 identifier used for broadcast communication, or a layer 2 identifier used for group communication, or a layer 2 identifier used for unicast communication. In each communication, it becomes possible to associate the V2X service with the NPN available for it. Information on the association between the V2X service and the NPN available for it may be notified between UEs as signaling or data in the above-mentioned V2X layer. PC5-S signaling may be used for this notification.

[0267] Another method is disclosed. The V2X layer notifies the AS layer of the association information between the V2X service and the NPN available for it. This is effective when the V2X layer recognizes the correspondence between the V2X service and the NPN available for it by the method described above. Alternatively, the AS layer may associate the V2X service with the NPN available for it. This is effective when the AS layer recognizes the association between the V2X service and the NPN available for it. The V2X layer may notify the AS layer of the layer 2 identifier, and the AS layer may associate the layer 2 identifier with the NPN-related information.

[0268] By doing so, it becomes possible to notify the own NPN-related information between UEs performing V2X services using PC5 communication.

[0269] The receiving UE performing PC5 communication receives the V2X service information notified from the transmitting UE and the NPN-related information to which the transmitting UE capable of using the V2X service belongs. Thereby, the receiving UE acquires the desired V2X service and the NPN-related information to which the transmitting UE capable of using it belongs. The receiving UE may determine whether access to the NPN of the transmitting UE is possible. The receiving UE may determine whether access to the NPN is possible using the NPN-related information to which the transmitting UE belongs, notified from the transmitting UE.

[0270] For example, the receiving UE collates the NPN-related information to which the transmitting UE belongs, notified from the transmitting UE, with the V2X service and the NPN-related information available for it, which are configured in the UE in advance. If the same NPN exists, the receiving UE determines that access is possible and communicates with the transmitting UE. If the same NPN does not exist, the receiving UE determines that access is impossible and does not communicate with the transmitting UE. When the receiving UE determines that access is impossible, it may perform again the process of detecting the PC5 communication request from the transmitting UE, including the information on the desired V2X service and the NPN available for it.

[0271] The receiving UE may notify the transmitting UE of the access permission determination result. For example, the receiving UE transmits a PC5 communication acceptance to the transmitting UE. The receiving UE may include its own NPN related information in the PC5 communication acceptance message. The transmitting UE may perform NPN access permission verification using the NPN related information of the receiving UE received from the receiving UE.

[0272] For example, the transmitting UE compares the NPN related information of the receiving UE notified by the receiving UE with the NPN related information transmitted by its own UE. If the same NPN exists, the transmitting UE enables access and communicates with the receiving UE. If the same NPN does not exist, the transmitting UE determines that access is impossible and does not communicate with the transmitting UE. By doing so, the transmitting UE performs NPN access permission verification.

[0273] In the foregoing, it has been disclosed that the receiving UE performs access permission determination and the transmitting UE performs access permission verification. As another method, the access permission determination by the foregoing receiving UE may be used as access permission verification. The receiving UE will perform access permission verification.

[0274] By doing so, it becomes possible to implement access control in the NPN among UEs performing V2X services using PC5 communication. It becomes possible to implement V2X services using PC5 communication among UEs belonging to the same NPN. Also, it is possible to make it impossible to implement V2X services using PC5 communication among UEs belonging to different NPNs.

[0275] FIG. 20 is a diagram showing a first example of a sequence for performing PC5 communication outside the coverage of a cell to which its own NPN belongs for Modification Example 3 of Embodiment 1. FIG. 20 shows an example in which a UE performs scheduling of PC5 communication. Also, FIG. 20 shows an example in which a transmitting UE performs NPN access permission verification. In FIG. 20, the same step numbers are assigned to steps common to FIGS. 18 and 19, and the common description is omitted.

[0276] In step ST1521, a V2X service using PC5 communication occurs in the transmitting UE. In step ST1724, the transmitting UE confirms that it is outside the coverage of the NPN to which the UE belongs. In step ST1739, the transmitting UE derives the V2X service and the NPN that can utilize the V2X service. For this derivation, information regarding the NPN that can utilize the V2X service, which is pre-configured in the transmitting UE, may be used.

[0277] The transmitting UE derives the NPN corresponding to the V2X service and derives the PC5 communication resources available with the derived NPN. For this derivation, information on the PC5 communication resources available with the NPN, which is pre-configured in the transmitting UE, may be used.

[0278] By doing so, the transmitting UE can recognize the PC5 communication resources available for the V2X service using the generated PC5 communication. The transmitting UE performs scheduling for PC5 communication using the PC5 communication resources, and in step ST1642, notifies the receiving UE of a PC5 communication request. PC5-S signaling may be used for the PC5 communication request. As disclosed in the methods of FIGS. 18 and 19, information regarding the NPN may be included in the PC5 communication request. The receiving UE can recognize the NPN-related information.

[0279] In step ST1743, the receiving UE may determine whether access is permitted based on the identifier of the NPN. The receiving UE can confirm whether the NPN corresponds to the received V2X service by using the information regarding the NPN that can utilize the V2X service, which is pre-configured in the receiving UE, and the NPN-related information notified from the transmitting UE in step ST1642. If the NPN corresponds to the received V2X service, the receiving UE may notify PC5 communication permission in step ST1645, and if not, may notify PC5 communication rejection. Alternatively, the receiving UE may not transmit anything.

[0280] The receiving UE transmits a PC5 communication permission to the transmitting UE in step ST1645. The PC5 communication permission may include NPN-related information. In step ST1746, when the transmitting UE receives the PC5 communication permission from the receiving UE, it determines that PC5 communication is possible; otherwise, it determines that PC5 communication is not possible. The transmitting UE may further determine the feasibility of PC5 communication using the NPN-related information included in the PC5 communication permission. If the NPN-related information included in the PC5 communication permission includes an NPN that can be used for V2X services using PC5 communication, the transmitting UE determines that PC5 communication is possible. Otherwise, the transmitting UE determines that PC5 communication is not possible.

[0281] By doing so, when the NPN is not available for the desired V2X service, it is possible to make PC5 communication impossible. In the transmitting UE, it becomes possible to perform NPN access feasibility verification.

[0282] FIG. 21 is a diagram showing a second example of a sequence for performing PC5 communication outside the coverage of a cell to which its own NPN belongs in Modification Example 3 of Embodiment 1. FIG. 21 shows an example in which a UE performs scheduling of PC5 communication. Also, FIG. 21 shows an example in which the transmitting UE does not perform NPN access feasibility verification and the receiving UE performs NPN access feasibility verification. In FIG. 21, the same step numbers are assigned to the steps common to FIG. 20, and the common descriptions are omitted.

[0283] The receiving UE may perform access feasibility verification using the identifier of the NPN in step ST1844. The receiving UE can confirm whether the NPN corresponds to the received V2X service by using the information on the NPNs available for V2X services configured in advance in the receiving UE and the NPN-related information notified from the transmitting UE in step ST1642. If the NPN corresponds to the received V2X service, the receiving UE may notify the PC5 communication permission in step ST1645; otherwise, it may notify the PC5 communication rejection. Alternatively, the receiving UE may not transmit anything.

[0284] By doing so, the desired V2X service can be implemented only in the NPN where the PC5 communication is available for the desired V2X service. If the NPN is not available for the desired V2X service, the PC5 communication can be made impossible. In the receiving UE, it is possible to perform NPN access availability verification. Therefore, it is possible to eliminate the need for NPN access availability verification in the transmitting UE.

[0285] Before transmitting a PC5 communication request, the transmitting UE may determine whether NPN access is available. The determination of whether PC5 communication can be performed may be used as the determination of whether NPN access is available. As a determination criterion, for example, information on whether the UE pre - possesses the PC5 communication resources for the V2X service to be implemented may be used. If the transmitting UE does not use the cell belonging to its own NPN as the serving cell and the UE possesses the PC5 communication resources for the V2X service to be implemented, it is determined that the PC5 communication can be performed. If the transmitting UE does not use the cell belonging to its own NPN as the serving cell and the UE does not possess the PC5 communication resources for the V2X service to be implemented, it is determined that the PC5 communication cannot be performed.

[0286] As a determination criterion, for example, information on whether the V2X service to be implemented is available in the NPN to which the UE belongs may be used. If the V2X service to be implemented is available in the NPN to which the UE belongs, the transmitting UE determines that the PC5 communication can be performed. If the V2X service to be implemented is not available in the NPN to which the UE belongs, the transmitting UE determines that the PC5 communication can be performed.

[0287] The above - mentioned determination criteria may be used together. For example, if the V2X service to be implemented is available in the NPN to which the UE belongs and the UE possesses the PC5 communication resources for the V2X service, the PC5 communication is made possible. Otherwise, the PC5 communication is made impossible.

[0288] By doing so, in the transmitting UE, it becomes possible to perform the process of determining whether NPN access is available. The determination of whether NPN access is available in the transmitting UE may be applied to, for example, the example disclosed in FIG. 20. In FIG. 20, before transmitting a PC5 communication request in step ST1642, the transmitting UE performs the determination of whether NPN access is available in the aforementioned transmitting UE. If the transmitting UE determines that NPN access is possible and PC5 communication is possible, the transmitting UE transmits a PC5 communication request. If the transmitting UE determines that NPN access is not available and PC5 communication is not possible, the transmitting UE does not transmit a PC5 communication request.

[0289] By doing so, in the example of FIG. 20, it becomes possible to perform the process of determining whether NPN access is available by the transmitting UE. When the transmitting UE determines that NPN access is not available, it will not transmit a PC5 communication request, so it is possible to eliminate the wasteful use of resources in PC5 communication and reduce interference.

[0290] The determination of whether NPN access is available in the transmitting UE may be applied to, for example, the example disclosed in FIG. 21. In FIG. 21, before transmitting a PC5 communication request in step ST1642, the transmitting UE performs the determination of whether NPN access is available in the aforementioned transmitting UE. If the transmitting UE determines that NPN access is possible and PC5 communication is possible, the transmitting UE transmits a PC5 communication request. If the transmitting UE determines that NPN access is not available and PC5 communication is not possible, the transmitting UE does not transmit a PC5 communication request.

[0291] By doing so, in the example of FIG. 21, it becomes possible to perform the process of determining whether NPN access is available by the transmitting UE. When the transmitting UE determines that NPN access is not available, it will not transmit a PC5 communication request, so it is possible to eliminate the wasteful use of resources in PC5 communication and reduce interference.

[0292] In the example of FIG. 21, by adding the NPN access permission determination process by the transmitting UE, it becomes possible to make the UE that performs the NPN access permission determination process different from the UE that performs the NPN access permission verification. It becomes possible to implement NPN access control with a plurality of different UEs.

[0293] In addition, since it becomes possible to implement access control in the UE that executes PC5 communication, the problem that the UE that executes PC5 communication communicates with a UE outside its own NPN can be solved.

[0294] A method that enables PC5 communication was disclosed for the case where a cell to which the UE belongs in its own NPN cannot be found. As another method, when a cell to which the UE belongs in its own NPN cannot be found, PC5 communication may be prohibited. By doing so, it becomes unnecessary to implement access control to the NPN for the UE. Therefore, the processing as a system using the NPN can be simplified.

[0295] According to the method disclosed in Modification Example 3 of Embodiment 1, even when a cell to which the UE belongs in its own NPN cannot be found, PC5 communication becomes possible and a V2X service using PC5 communication can be implemented.

[0296] Modification Example 4 of Embodiment 1. PC5 communication is communication between UEs. For this reason, for example, even when the UE exists within the coverage of a cell belonging to another NPN, it is required to enable PC5 communication, which is communication between UEs. In this Modification Example 4, a method that enables PC5 communication even when the UE exists within the coverage of a cell belonging to another NPN is disclosed.

[0297] A UE performing PC5 communication is permitted to access a cell different from its own NPN. The UE performing PC5 communication determines whether it can access a cell different from its own NPN. For example, the UE determines whether it can access a cell different from its own NPN by determining whether the UE itself has V2X capabilities. The UE may also determine whether it has PC5 communication capabilities. If it has PC5 communication capabilities, the UE may access a cell different from its own NPN. Otherwise, the UE does not access a cell different from its own NPN. The UE performing PC5 communication can determine whether it can access a cell different from its own NPN even when no V2X service is occurring. It is possible for the UE performing PC5 communication to perform V2X authentication and V2X policy provisioning processes in advance via a cell different from its own NPN.

[0298] Depending on the type of NPN to which the cell different from the own NPN belongs, access may be permitted or prohibited differently. For example, access is not permitted to a cell belonging to an S-NPN different from the NPN to which the UE performing PC5 communication belongs. Access is permitted to a cell belonging to an NS-NPN different from the NPN to which the UE performing PC5 communication belongs. By doing so, access to a different S-NPN can be prohibited even in the case of PC5 communication. Therefore, it becomes possible to restrict access to UEs that do not belong to the S-NPN.

[0299] Also, for example, access may be permitted to a cell belonging to an S-NPN different from the NPN to which the UE performing PC5 communication belongs, and access may not be permitted to a cell belonging to an NS-NPN different from the NPN to which the UE performing PC5 communication belongs. By doing so, access to a different NS-NPN can be prohibited even in the case of PC5 communication. Therefore, it becomes possible to restrict access to UEs that do not belong to the NS-NPN.

[0300] There are cases where one PLMN becomes one S-NPN and cases where one PLMN consists of multiple S-PLMs. For example, for cells belonging to a different NPN of the same PLMN as the NPN to which the UE performing PC5 communication belongs, access may be permitted, and for cells belonging to other different NPNs, access may not be permitted. By doing so, even in the case of PC5 communication, it becomes possible to limit the NPNs for which access is permitted. It becomes possible to restrict the UEs that can access.

[0301] The UE may determine whether the V2X service to be implemented is a V2X service using PC5 communication. In the case of a V2X service using PC5 communication, the UE may access a cell different from its own NPN. Otherwise, the UE does not access a cell different from its own NPN. When a V2X service using PC5 communication occurs, the UE becomes able to access a cell different from its own NPN. Also, when a V2X service using PC5 communication occurs, the UE can perform V2X authentication and V2X policy provisioning processing via a cell different from its own NPN.

[0302] The RAN node (such as gNB) may not perform NPN access control when the UE accesses. Conventionally, in NPN access control, the UE makes a determination on whether access is possible, and the AMF verifies whether access is possible. Even when a UE performing PC5 communication accesses a cell different from its own NPN, the RAN node may not perform NPN access control. The RAN node may notify the information received from the UE to the AMF.

[0303] As another method, the RAN node may perform NPN access control when the UE accesses. The RAN node may determine whether the UE is capable of PC5 communication. For example, the RAN node determines whether the UE has PC5 communication capability. The UE includes the PC5 communication capability in the notification to the RAN node and notifies it. Thereby, the RAN node can determine whether the UE is capable of PC5 communication.

[0304] When the RAN node determines that access is possible if the PC5 communication capability is included in the notification from the UE, the RAN node permits the access of the UE. When the RAN node permits the access of the UE, the RAN node may notify the AMF of the PC5 communication capability. Otherwise, the RAN node determines that access is impossible and does not permit the access of the UE. When the RAN node does not permit the access of the UE, the RAN node may notify the UE of a rejection. The cause information may be included in the rejection.

[0305] When the RAN node determines that access is possible if the PC5 communication capability is included in the notification from the UE, the RAN node may transmit a grant for a V2X service-related information provision request to the UE. The UE may notify the AMF of a V2X service-related information provision request in a NAS message. The RAN node may transmit a grant for the NAS message notified by the UE to the AMF. By doing so, when a V2X service using PC5 communication occurs in the UE, it becomes possible to perform V2X authentication and V2X policy provision processing via a cell different from its own NPN.

[0306] Also, for example, the RAN node may determine whether the UE has accessed in order to perform a V2X service or in order to perform a V2X service using PC5 communication. When accessing the RAN node for a V2X service, the UE includes the PC5 communication capability in the notification to the RAN node. Thereby, the RAN node can determine whether the UE is PC5 communication-capable.

[0307] A UE performing PC5 communication is allowed to access the AMF via a cell different from its own NPN. The AMF may implement access control for the NPN when the UE accesses. The AMF may determine whether the access from the UE uses PC5 communication. For example, if the access from the UE is for implementing a V2X service using PC5 communication, the AMF permits the UE to access an NPN different from its own NPN. Otherwise, the AMF does not permit the UE to access an NPN different from its own NPN.

[0308] A specific example of a method for the AMF to determine whether the access from the UE uses PC5 communication is disclosed. The AMF may determine whether the access from the UE uses PC5 communication by determining whether the signaling notified from the UE via the RAN node includes PC5 communication capability. If the PC5 communication capability is included in the notification from the UE, the AMF determines that it is accessible and permits the access of the UE. When permitting the access of the UE, the AMF may request the PCF for V2X service authentication and provision of V2X policies to the UE. Otherwise, the AMF determines that it is not accessible and does not permit the access of the UE. When not permitting the access of the UE, the AMF may notify the UE of a rejection. Cause information may be included in the rejection.

[0309] Also, when the AMF permits the access of the UE, the AMF may notify the UE of the access permission. The access permission may be notified via the RAN node. Thereby, the UE can recognize that the access to the NW side via a cell different from its own NPN is permitted.

[0310] It is possible to perform V2X authentication and V2X policy provision processing for a UE performing PC5 communication via a cell different from its own NPN. Using the method described above, the UE performing PC5 communication and the PCF may perform V2X authentication and V2X policy provision processing.

[0311] When the AMF permits access to a UE that performs PC5 communication belonging to an NPN different from the NPN to which the AMF itself belongs, registration from the UE to the AMF may not be required. When the UE accesses the NW via a cell different from its own NPN, registration may not be required. By doing so, the UE can perform only V2X service authentication using PC5 communication and provision of V2X service-related information.

[0312] When the UE that performs the PC5 communication accesses the NW via a cell different from its own NPN, the registration management state may be set to an unregistered state. When the UE that performs the PC5 communication accesses the NW via a cell different from its own NPN, the connection management state may be set to an idle state. These state managements are performed by the UE and the AMF.

[0313] A state for managing multiple UEs that perform PC5 communication may be provided. For example, an RRC state for managing whether the UEs that perform PC5 communication are RRC-connected may be provided. For example, a link connection management state for managing whether a PC5-S link is connected may be provided between the UEs that perform PC5 communication. By doing so, it becomes possible to facilitate state transition processing in the UE that performs PC5 communication and reduce malfunction.

[0314] Another method is disclosed. When the access from the UE is for accessing to perform a V2X service using PC5 communication, the AMF may perform V2X service authentication and V2X policy provision processing between the PCF and the UE, and then perform NPN access control.

[0315] The AMF determines whether the access from the UE uses PC5 communication. As a result of the determination, if the access from the UE is for accessing the V2X service using PC5 communication, the AMF requests the PCF to perform V2X service authentication and provide the V2X policy to the UE, notifies the UE of the V2X policy provided by the PCF in response to the request, and then may perform NPN access control for the UE.

[0316] An example of NPN access control for the UE is disclosed. If the access from the UE is to the same NPN as its own NPN, the AMF determines that the access is possible and permits the UE's access. If the access from the UE is to an NPN different from its own NPN, the AMF determines that the access is impossible and does not permit the UE's access. If the UE's access is not permitted, the AMF may notify the UE of the rejection. The cause information may be included in the rejection.

[0317] The AMF may provide the V2X policy for the UE included in the rejection notification for NPN access. The AMF may include the V2X policy for the UE in the cause information. The AMF may notify the V2X policy for the UE together with the cause information.

[0318] By doing so, before the UE is determined to be unable to access by the NPN access control at the AMF, authentication for the V2X service using PC5 communication and V2X policy provision processing can be performed between the UE and the CN. Even if the access from the UE is to an NPN different from its own NPN, the UE can receive V2X service authentication and the provision of the V2X policy.

[0319] The scheduling for PC5 communication for the UE is performed by a RAN node of an NPN different from the UE's NPN. In other words, a V2X service using PC5 communication in mode 1 is implemented. To implement a V2X service using PC5 communication in mode 1, the PCF may provide a V2X policy to the RAN node accessed by the UE. The PCF may provide the V2X policy via the AMF. The above-described NPN access control method may be applied. Also, the above-described V2X policy provision method may be appropriately applied. The V2X policy may be provided from the PCF not to the UE but to the RAN node accessed by the UE.

[0320] As described above, the V2X service-related information may include information in which the NPN-related information available for the V2X service is associated. As the V2X service-related information, a V2X policy or V2X parameter, V2X service information, and information on the NPN available for it may be included. Also, the V2X policy or V2X parameter may include the V2X service information and the V2X parameters of the NPN available for it. The V2X service-related information may be a V2X policy or V2X parameter including the V2X service information and the V2X parameters of the NPN available for it. The V2X policy or V2X parameter may be, for example, a V2X policy or V2X parameter on PC5 (also referred to as on the PC5 reference point).

[0321] A method for the UE to perform PC5 communication is disclosed. When a V2X service using PC5 communication occurs in the UE, the UE performs an RRC connection to the RAN node. The RAN node may belong to an NPN different from the UE's NPN. The RAN node may apply the above-described access control method when a UE belonging to an NPN different from its own NPN accesses. Thereby, the UE can access the RAN node.

[0322] The UE notifies the RAN node of a BSR (Buffer Status Report) for indicating the amount of data generated in the V2X service using PC5 communication. The BSR may be notified by RRC signaling or by MAC signaling. In the case of RRC signaling, the BSR may be included and notified, for example, in a UE assistance information message. Also, for example, the BSR may be notified during the RRC connection establishment procedure.

[0323] Instead of the BSR, the UE may notify information indicating a scheduling request for PC5 communication. In this case, the base station cannot recognize the amount of data of the UE's V2X service. The base station may perform scheduling corresponding to a predetermined amount of data and notify the UE of the scheduling information. The predetermined amount of data may be determined in advance. The UE may perform scheduling corresponding to at least the amount of data for which the BSR can be transmitted and notify the UE of the scheduling information.

[0324] By doing so, the RAN node can recognize that a UE not belonging to its own NPN is requesting scheduling for PC5 communication. The RAN node can perform scheduling for PC5 communication and notify the UE of the scheduling information for the UE with respect to a UE not belonging to its own NPN.

[0325] Specific examples of the scheduling information for PC5 communication are shown below as (1) to (10).

[0326] (1) Information regarding the RAT.

[0327] (2) Information regarding the frequency.

[0328] (3) Information regarding the BWP (Band Width Part).

[0329] (4) Resource allocation information.

[0330] (5) MCS information.

[0331] (6) Information related to HARQ.

[0332] (7) Information related to CSI.

[0333] (8) Information related to transmission power.

[0334] (9) Information related to power measurement.

[0335] (10) Combinations of (1) to (9).

[0336] The information related to the RAT of the aforementioned (1) may be information indicating the RAT for performing PC5 communication. The information indicating the RAT may be, for example, information indicating whether it is LTE or NR.

[0337] The aforementioned resource allocation information of (4) may be, for example, resource allocation information for each channel used for PC5 communication, resource allocation information of a reference signal (RS). As channels, for example, there are PSCCH, PSSCH, etc. Also, the resource allocation information may be resource allocation information in the frequency-time domain. The resource allocation information may be in units of one or more RBs, one or more subchannels, one or more symbols, or one or more slots. Also, the resource allocation information of the RS may include sequence information used for the RS.

[0338] The information regarding the HARQ in (6) above is, for example, the number of repetitions, resource allocation information in the case of repeated transmission, scheduling information for HARQ feedback (e.g., Ack and / or Nack) transmission, etc. As the scheduling information for repeated transmission or HARQ feedback transmission, the above-mentioned scheduling information for PC5 communication may be applied. Also, the resource allocation information may be the transmission bandwidth or the transmission timing. By doing so, the transmitting UE performing PC5 communication can perform HARQ processing. Also, the receiving UE performing PC5 communication can perform scheduling for transmitting HARQ feedback.

[0339] The transmitting UE may notify the receiving UE of the scheduling information for HARQ feedback using PC5 communication. The receiving UE can transmit HARQ feedback by receiving the scheduling information for HARQ feedback.

[0340] The information regarding the CSI in (7) above is, for example, the setting information of the CSI reference signal (RS) on PC5, the scheduling information for CSI report transmission, etc. The setting information may be the above-mentioned resource allocation information. As the scheduling information for CSI report transmission, the above-mentioned scheduling information for PC5 communication may be applied. Also, the resource allocation information may be the transmission bandwidth or the transmission timing. By doing so, the transmitting UE performing PC5 communication can perform CSI RS transmission. Also, the receiving UE performing PC5 communication can perform CSI reporting.

[0341] The transmitting UE may notify the receiving UE of the scheduling information for CSI report transmission using PC5 communication. The receiving UE can transmit CSI reports by receiving the scheduling information for CSI reports.

[0342] The information regarding the transmission output of the foregoing (8) may be the transmission power of a channel or RS transmitted by the transmitting UE. Alternatively, the information may be a parameter value for deriving the transmission power. The transmitting UE derives the transmission power using the parameter. Further, the information may be the transmission power of a channel or RS transmitted by the receiving UE. The information may be the transmission power of HARQ feedback or CSI reporting. Alternatively, the information may be a parameter value for the receiving UE to derive the transmission power. The base station can set the transmission power in consideration of the interference received by the transmitting UE and the receiving UE from other UEs, or the interference given by the transmitting UE and the receiving UE to other UEs.

[0343] The information regarding the power measurement of the foregoing (9) is, for example, the setting information of a channel or RS for power measurement on PC5, the scheduling information for transmitting the power measurement result report, etc. The setting information may be the foregoing resource allocation information. As the scheduling information for transmitting the power measurement result report, the foregoing scheduling information for PC5 communication may be applied. Further, the resource allocation information may be the transmission band or the transmission timing. By doing so, the transmitting UE performing PC5 communication can perform the transmission of the RS for power measurement. Also, the receiving UE performing PC5 communication can perform the transmission of the power measurement result report.

[0344] The transmitting UE may notify the receiving UE of the channel or RS setting for power measurement using PC5 communication. The receiving UE measures the channel or RS for power measurement using the received channel or RS setting for power measurement and derives the received power. The transmitting UE may notify the receiving UE of the scheduling information for transmitting the power measurement result report using PC5 communication. The receiving UE can transmit the measured received power measurement result to the transmitting UE using the scheduling.

[0345] The information to be notified from the transmitting UE to the receiving UE, or the information to be notified from the receiving UE to the transmitting UE, may be notified using PC5-S signaling, or may be notified using RRC signaling, or may be notified using MAC signaling. Alternatively, the information may be included in the SCI and notified on the PSCCH, or may be notified on the feedback channel (PSFCH).

[0346] By using PC5-S signaling, notification can be made earlier. By using RRC signaling, notification can be made at the AS layer. For example, it is effective for notifying information at the AS layer. By using MAC signaling, notification can be made with low latency. Also, by applying HARQ to MAC signaling, the error rate can be reduced. By using the PSCCH or PSFCH, notification can be made with low latency.

[0347] Different notification methods may be used for each piece of information. For example, the setting information of the RS for power measurement in PC5 communication may be notified using PC5-S signaling, and the power measurement result may be notified using RRC signaling. By doing so, the receiving UE can perform power measurement earlier, and can notify the transmitting UE of the power measurement result earlier after RRC connection. As a result, the transmitting UE can perform appropriate transmission power control earlier. By appropriately using different notification methods for each piece of information, it is possible to improve the communication quality of PC5 communication.

[0348] The transmitting UE may notify the receiving UE of the V2X service information using PC5 communication and the information of the NPN available for the V2X service. Alternatively, the transmitting UE may notify any one of the information. The receiving UE may determine whether NPN access is possible using the information related to the NPN associated with the V2X service acquired in advance and the V2X service information using PC5 communication and the information related to the NPN available for the V2X service notified from the transmitting UE. The method disclosed in Modification Example 3 of Embodiment 1 may be applied.

[0349] The receiving UE may notify the transmitting UE of the access permission determination result. For example, the receiving UE transmits a PC5 communication acceptance to the transmitting UE. The receiving UE may include its own NPN-related information in the PC5 communication acceptance message. The transmitting UE may perform NPN access permission verification using the NPN-related information of the receiving UE received from the receiving UE. The method disclosed in Modification Example 3 of Embodiment 1 may be applied. By doing so, it becomes possible to perform NPN access permission verification in the transmitting UE.

[0350] Also, by applying the method disclosed in Modification Example 3 of Embodiment 1, the access permission determination by the aforementioned receiving UE may be used as access permission verification. The receiving UE will perform access permission verification.

[0351] By doing so, even when the RAN node that performs scheduling for PC5 communication in Mode 1 belongs to an NPN different from the NPN to which the transmitting UE belongs, it becomes possible to perform NPN access control. In the receiving UE that performs PC5 communication, it becomes possible to perform NPN access permission determination.

[0352] FIGS. 22 and 23 are diagrams showing an example of a sequence for performing PC5 communication via a cell that does not belong to its own NPN for Modification Example 4 of Embodiment 1. FIGS. 22 and 23 are connected at the position of the boundary line BL2223. FIGS. 22 and 23 show an example in which a RAN node (base station) performs scheduling of PC5 communication for the UE. In FIGS. 22 and 23, the same step numbers are assigned to the steps common to FIGS. 16, 17, and 20, and the common explanations are omitted.

[0353] In step ST1905, the transmitting UE determines whether it can access a cell that does not belong to its NPN. For access for V2X services using PC5 communication, the transmitting UE determines that it can access a cell that does not belong to its NPN; otherwise, it determines that access is not possible. The RAN node may notify the UE of NPN-related information, and the UE receives the notified NPN-related information. In step ST1905, even if its own NPN is not present in the received NPN-related information, the UE determines that it can access the RAN node for access for PC5 communication.

[0354] If the UE determines that access is possible, in step ST1908, it accesses the RAN node and notifies the RAN node of its V2X capabilities. In step ST1909, the RAN node notifies the AMF of the V2X capabilities received from the UE. As the method for notifying the V2X capabilities from the transmitting UE to the AMF, the methods disclosed in FIGS. 16 and 17 may be appropriately applied.

[0355] The AMF does not perform NPN access feasibility verification for the UE. For the UE that has notified V2X capabilities for PC5 communication, the AMF does not determine whether the UE can access the NW. The AMF recognizes that it can provide V2X services using the V2X capabilities received from the UE.

[0356] In step ST1413, the AMF notifies the PCF of the V2X capabilities received from the UE. For this notification, for example, the Npcf interface may be used, or the UE Policy Control Create Request message may be used.

[0357] At step ST1414, the PCF performs V2X service authentication using the UE's registration data. Also, the PCF determines to provide a V2X policy to the UE. Further, the PCF determines to provide the UE with information on the V2X service and the NPNs available for using it. The V2X policy may include V2X parameters. The V2X policy may also include information on the V2X service and the NPNs available for using it.

[0358] At step ST1415, the PCF notifies the AMF of V2X communication related information. At step ST1416, the AMF notifies the RAN node of the V2X communication related information received from the PCF. The AMF may also notify the UE of the V2X communication related information received from the PCF. For example, at steps ST1416 and ST1417, the AMF may notify the UE of the V2X communication related information. At step ST1417, the RAN node notifies the UE of the V2X communication related information. By doing so, the UE can also obtain the V2X communication related information.

[0359] At step ST1521, in the transmitting UE, a V2X service using PC5 communication occurs. Even if the transmitting UE is present within the coverage of a cell that does not belong to its own NPN, at step ST1534, it notifies the cell of a BSR for PC5 communication. The RAN node that has received the BSR for PC5 communication performs PC5 communication scheduling for the transmitting UE at step ST1535. Steps ST1739 to ST1552 may appropriately apply the method disclosed in Figure 20.

[0360] By doing so, even if the UE is present within the coverage of a cell that does not belong to its own NPN, PC5 communication can be performed via the cell.

[0361] By the method disclosed in Modification Example 4 of Embodiment 1, the UE can execute PC5 communication even when it cannot find a cell belonging to its own NPN. The UE can execute PC5 communication even when it can only find cells different from its own NPN. It becomes possible to implement a V2X service using PC5 communication. Also, the UE can perform V2X service authentication and V2X policy provisioning processing with the CN via a RAN node of an NPN different from the NPN to which the UE belongs. For example, the UE can perform an update of the V2X policy even when it can only find cells different from its own NPN. Therefore, it is also possible to update QoS parameters. The latest communication status and NW load status can be reflected in the V2X policy.

[0362] Modification Example 5 of Embodiment 1. In this Modification Example 5, another method for solving the problems disclosed in Modification Example 4 of Embodiment 1 is disclosed.

[0363] When a UE performing PC5 communication exists within the coverage of a cell belonging to an NPN different from the UE itself, scheduling for PC5 communication between the opposing UEs is performed. This method is preferably applied when implementing a V2X service using Mode 2 PC5 communication, which is a method in which a transmitting UE performing PC5 communication performs scheduling.

[0364] The resources for PC5 communication are notified, for example, from a base station. A UE performing PC5 communication may perform PC5 communication scheduling using the resources for PC5 communication notified from a cell belonging to an NPN different from the UE itself. The receiving UE may detect PC5 communication from the transmitting UE using the resources for PC5 communication notified from a cell belonging to an NPN different from the UE itself.

[0365] When implementing a V2X service using PC5 communication, the UE determines that it can receive the resource information for PC5 communication notified from a cell belonging to an NPN different from the UE itself. Otherwise, the UE may determine that it cannot receive the resource information for PC5 communication notified from a cell belonging to an NPN different from the UE itself.

[0366] By doing so, when a UE performing PC5 communication is within the coverage of a cell belonging to an NPN different from its own UE, it becomes possible to perform PC5 communication.

[0367] However, a cell belonging to an NPN different from the NPN to which the UE belongs does not necessarily notify the PC5 communication resources available in the NPN to which the UE belongs. For this reason, the UE cannot perform PC5 communication using the PC5 communication resources notified from a cell belonging to an NPN different from its own UE. A method for solving such a problem is disclosed.

[0368] The PC5 communication resources available in the NPN to which the own UE belongs may be configured in the UE in advance. As the method for setting the NPN and the PC5 communication resources available in the NPN, the method disclosed in Modification Example 2 of Embodiment 1 may be applied. Also, the PC5 communication resources may be set for each V2X service. As this method, the method disclosed in Modification Example 2 of Embodiment 1 may be applied.

[0369] By doing so, even when the PC5 communication resources notified from a cell belonging to an NPN different from the own UE are not available in the NPN to which the own UE belongs, the UE can perform scheduling using the PC5 communication resources configured in the own UE, thereby making it possible to perform PC5 communication. A V2X service using PC5 communication becomes possible.

[0370] When the PC5 communication resources are configured in the UE in advance, the PC5 communication resources may be updated by the PCF. The update of the PC5 communication resources may be provided from the PCF to the UE using the V2X policy provisioning process. As the method for the UE to perform the V2X policy provisioning process via a RAN node or a CN belonging to an NPN different from the NPN to which the UE belongs, the method disclosed in Modification Example 4 of Embodiment 1 may be appropriately applied.

[0371] As another method, CN may notify the RAN node of the information of the NPN to which the UE belongs and the PC5 communication resources available in that NPN. For example, the PCF may notify the RAN node of the information of the NPN to which the UE belongs and the PC5 communication resources available in that NPN. The UE may request the PCF to provide a V2X policy to the RAN node. Information for requesting the provision of a V2X policy to the RAN node may be provided, and the UE may notify the AMF of this information. The PCF may include the information of the NPN to which the UE belongs and the PC5 communication resources available in that NPN in the V2X policy and then notify it.

[0372] The UE may notify the AMF of the information for identifying the UE, such as UE identifier information, and / or the information for identifying the RAN node, such as the identifier information of the RAN node, together with the information for requesting the provision of a V2X policy to the RAN node. The AMF may request the PCF to provide a V2X policy to the RAN node. In response to this request, the PCF provides a V2X policy to the RAN node via the AMF. The method for providing a V2X policy from the PCF to the RAN node may appropriately apply the method disclosed in Modification Example 4 of Embodiment 1.

[0373] By doing so, the RAN node can recognize the PC5 communication resources available in the NPN to which the UE belongs. The RAN node notifies the PC5 communication resources available in the NPN to which the UE belongs. The RAN node may notify the information regarding the NPN to which the UE belongs and the PC5 communication resources available in that NPN in association with each other. By doing so, the UE can perform PC5 communication using the PC5 communication resources notified from a cell belonging to an NPN different from its own UE. It becomes possible to implement a V2X service using PC5 communication.

[0374] FIG. 24 and FIG. 25 are diagrams showing a first example of a sequence for performing PC5 communication via a cell not belonging to the home NPN for Modification Example 5 of Embodiment 1. FIG. 24 and FIG. 25 are connected at the position of the boundary line BL2425. FIGS. 24 and 25 show an example in which the UE performs scheduling of PC5 communication. In FIGS. 24 and 25, the same step numbers are assigned to the steps common to FIGS. 18 to 20 and FIGS. 22 to 23, and the common descriptions are omitted.

[0375] In step ST1629, the RAN node notifies PC5 communication related information. In step ST1521, when a V2X service using PC5 communication occurs in the transmitting UE, the transmitting UE, in step ST2040, uses the V2X communication related information received in step ST1417 and the PC5 communication related information received in step ST1629 to associate the V2X service, the RP for PC5 communication for the V2X service, and the home NPN capable of using the V2X service.

[0376] The transmitting UE selects, in step ST1638, an RP corresponding to the home NPN capable of using the generated V2X service. The transmitting UE performs scheduling for PC5 communication using the selected RP. Through the processing from step ST1642 to step ST1746, the transmitting UE performs home NPN access availability verification. By doing so, when the home NPN cannot use the desired V2X service, PC5 communication can be made impossible. In the transmitting UE, home NPN access availability verification can be performed.

[0377] FIG. 26 and FIG. 27 are diagrams showing a second example of a sequence for performing PC5 communication via a cell not belonging to the home NPN with respect to Modification Example 5 of Embodiment 1. FIG. 26 and FIG. 27 are connected at the position of the boundary line BL2627. FIGS. 26 and 27 show an example in which the AMF performs NPN access availability verification for the UE. The V2X communication related information notified from the AMF to the UE is included in the rejection notification for NPN access. In FIGS. 26 and 27, the same step numbers are assigned to the steps common to FIGS. 18 to 19, FIGS. 24, and FIGS. 25, and the common descriptions are omitted.

[0378] In step ST1905, the transmitting UE determines whether it can access a cell not belonging to the home NPN. If the transmitting UE determines that it can access, in step ST1407, it accesses the RAN node and notifies the RAN node of the NPN related information and the V2X capability. In step ST1408, the RAN node notifies the AMF of the NPN related information and the V2X capability received from the UE. As the method for notifying the NPN related information and the V2X capability, the method disclosed in FIGS. 18 to 19 may be appropriately applied.

[0379] In step ST2112, the AMF performs NPN access availability verification for the UE with respect to the NW. The AMF performs NPN access availability verification using the NPN related information notified from the UE. Here, since the UE is accessing via a cell not belonging to the home NPN, the AMF determines that NPN access is impossible.

[0380] Also, even if it is determined that access is impossible by the NPN access availability verification, the AMF requests the PCF to provide V2X communication related information using the V2X capability information notified from the UE. Through the processing from step ST1413 to step ST1415, the AMF obtains the V2X related information for the UE from the PCF.

[0381] The AMF reserves the right to notify the RAN node and the UE of NPN access rejection until it obtains the V2X-related information. In steps ST2114 and ST2116, the AMF notifies the RAN node and the transmitting UE of NPN access rejection. The AMF includes the V2X-related information obtained in step ST1415 in the NPN access rejection. By doing so, the RAN node and the transmitting UE can obtain the V2X-related information.

[0382] In this way, by including the V2X-related information in the NPN access rejection and notifying the RAN node and the UE, the NPN access control (NPN access permission verification) process in the conventional AMF can be utilized. By reducing the additional processing, these processes can be easily implemented.

[0383] By the method disclosed in Modification Example 5 of Embodiment 1, the same effects as those shown in Modification Example 4 of Embodiment 1 can be obtained. In addition, since the UE performing PC5 communication performs PC5 communication scheduling and there is no need for the RAN node to perform PC5 communication scheduling, access such as the UE requesting PC5 communication from the RAN node becomes unnecessary. Therefore, PC5 communication can be started with low latency.

[0384] Embodiment 2. In NR-based PC5 communication, as a QoS management method for PC5, a method using QoS flows is implemented (see Non-Patent Document 21 (TS23.287)). A UE that performs PC5 communication is provided with a function of deriving QoS parameters from the service requests of V2X services using PC5 communication. The QoS parameters serve as indicators of the QoS of V2X services. Rules for deriving QoS parameters from the service requests of V2X services using PC5 communication (hereinafter sometimes referred to as QoS rules) may be configured in the UE in advance. Alternatively, the QoS rules may be provided from the CN to the UE. Alternatively, the QoS parameters may be configured in the UE in advance or provided from the CN to the UE. The PCF as the CN may provide the rules or QoS parameters to the UE via the AMF. The UE that performs PC5 communication performs PC5 communication scheduling using the QoS parameters.

[0385] The QoS parameters or QoS rules may be included in V2X-related information. The QoS parameters or QoS rules may be included in V2X policies or V2X parameters. The provision of QoS parameters or QoS rules from the CN side to the UE may apply the V2X-related information provision method or V2X policy provision method disclosed in Embodiment 1 or a modification thereof. By doing so, it is possible to avoid the processing method from becoming different and complicated, and it is possible to reduce malfunction.

[0386] In some cases, the RAN node (e.g., base station) may perform PC5 communication scheduling for the UE. In such a case, in order to perform PC5 communication scheduling at the base station, the base station may be provided with a function of deriving QoS parameters from the service requests of V2X services using PC5 communication. The rules or QoS parameters for deriving QoS parameters from the service requests of V2X services using PC5 communication may be provided from the CN. The PCF as the CN may provide the rules or QoS parameters to the base station via the AMF. The base station performs PC5 communication scheduling using the QoS parameters.

[0387] PC5 communication is carried out between UEs. The base station does not perform PC5 communication. Even if the base station schedules for PC5 communication for a UE, the base station does not perform PC5 communication. For this reason, the base station cannot recognize what the QoS of the PC5 communication carried out between UEs is like. For example, the base station cannot recognize whether the PC5 communication satisfies the required QoS. For this reason, for example, even when the communication quality of the PC5 communication deteriorates and does not satisfy the required QoS, the base station cannot recognize it and will continue to perform the same scheduling as before. The state of not satisfying the required QoS will continue.

[0388] Embodiment 2 discloses a method for solving such problems.

[0389] The UE that performs PC5 communication monitors the QoS in the PC5 communication. The UE that performs PC5 communication may be a transmitting UE or a receiving UE. The PC5 communication may be broadcast, group cast, or unicast. The UE may measure QoS parameters as the QoS monitor. The QoS monitor may be performed for all of the QoS parameters or for some of them.

[0390] The UE that has performed the QoS monitor notifies the base station of the QoS monitor result. The UE notifies the measurement result of the QoS parameters implemented as the QoS monitor. For example, the transmitting UE that performs PC5 communication measures the QoS parameters of the PC5 communication and notifies the measurement result of the QoS parameters to the base station that performs scheduling for the PC5 communication. By doing so, the base station that performs scheduling for PC5 communication can recognize the actual QoS of the PC5 communication.

[0391] As specific examples of the QoS parameters of PC5 to be measured, (1) to (11) are disclosed below.

[0392] (1) PQI.

[0393] (2) Resource type.

[0394] (3) Priority level.

[0395] (4) Packet Delay Budget.

[0396] (5) Packet Error Rate.

[0397] (6) Averaging window.

[0398] (7) Maximum Data Burst Volume.

[0399] (8) PC5 flow bit rates.

[0400] (9) PC5 Link Aggregated Bit Rates.

[0401] (10) Range.

[0402] (11) Combinations of (1) to (10).

[0403] UE that is performing PC5 communication may measure some or all of these QoS parameters to monitor the QoS of PC5 communication. The UE may directly measure these QoS parameters. Alternatively, the UE may measure other metrics and use the results to derive these QoS parameters.

[0404] The range of the aforementioned (10) indicates the minimum distance that needs to satisfy QoS. Therefore, a UE performing PC5 communication may derive the distance between UEs performing PC5 communication. A method for a UE performing PC5 communication to derive the distance between UEs performing PC5 communication is disclosed.

[0405] It is advisable to use the received power in PC5 communication. The received power may be, for example, RSRP. The RSRP in PC5 communication is also referred to as SL-RSRP. A receiving UE performing PC5 communication measures the SL-RSRP of the signal transmitted from the opposing transmitting UE. The receiving UE notifies the transmitting UE of the measurement result of the SL-RSRP. As the measurement result of the SL-RSRP, the receiving UE may notify the measured value. Alternatively, the receiving UE may divide the value of the SL-RSRP into one or more ranges and notify information indicating which range the measured value belongs to. This can reduce the amount of information required for notification.

[0406] The transmitting UE derives the distance between UEs using the SL-RSRP of the PC5 communication notified from the receiving UE. The transmitting UE recognizes the transmission power of the transmission signal of the PC5 communication. The transmitting UE may derive the radio wave propagation loss between UEs using the transmission power and the SL-RSRP of the PC5 communication obtained from the receiving UE, and derive the distance between UEs from the radio wave propagation loss. By doing so, the transmitting UE can derive the distance between UEs performing PC5 communication.

[0407] Another method is disclosed. A UE performing PC5 communication derives its own position. The transmitting UE notifies the receiving UE of its own position information. The receiving UE receives the position information from the transmitting UE and derives the distance between UEs using the position information of the transmitting UE and its own position information. The receiving UE notifies the transmitting UE of the derived distance between UEs. The derivation of the position at the UE may use GNSS or a RAN node. The RAN node may be, for example, a gNB of NR or an eNB in LTE. By doing so, the transmitting UE can derive the distance between UEs performing PC5 communication.

[0408] The transmitting UE may derive the distance between itself and the receiving UE. The receiving UE notifies the transmitting UE of its own location information. The transmitting UE receives the location information from the receiving UE, and uses the location information of the receiving UE and its own location information to derive the distance between the UEs. By doing so, the transmitting UE can derive the distance between the UEs performing PC5 communication.

[0409] The location information may be information indicating the area where the UE is located. For example, the area is divided into predetermined areas in advance, and identifiers are provided for the areas. The distance may be derived from the area identifiers where each UE is located. By doing so, the amount of location information notified between the UEs can be reduced.

[0410] Another method is disclosed. The receiving UE derives the radio wave propagation loss between the UEs performing PC5 communication. The transmitting UE notifies the receiving UE of the transmission power of the transmission signal for PC5 communication. RRC signaling may be used for this notification, which is effective when the transmission power is changed quasi-statically. Alternatively, MAC signaling may be used, which is effective when the transmission power is changed relatively early. Alternatively, the transmitting UE may include the transmission power to be notified in the SCI and notify it on the SPCCH. This is effective when the transmission power is changed dynamically. The value of the transmission power to be notified may be the difference from the previous transmission power.

[0411] The receiving UE performing PC5 communication measures the reception power of the signal transmitted from the opposing transmitting UE. The receiving UE uses the measured reception power and the transmission power value notified from the transmitting UE to derive the radio wave propagation loss. The receiving UE may notify the transmitting UE of the derived radio wave propagation loss. The transmitting UE may use the radio wave propagation loss notified from the receiving UE to derive the distance between the UEs. By doing so, the transmitting UE can derive the distance between the UEs performing PC5 communication.

[0412] The receiving UE may derive the distance between the UEs from the radio wave propagation loss. The receiving UE notifies the transmitting UE of the derived distance between the UEs. By doing so, the transmitting UE can recognize the distance between the UEs performing PC5 communication.

[0413] The above-mentioned SL-RSRP, radio propagation loss, or UE-to-UE distance may be notified periodically or aperiodically. In the case of periodic notification, the transmitting UE may notify the receiving UE in advance of the notification period of the UE-to-UE distance. In the case of aperiodic notification, the transmitting UE may request the receiving UE to notify the SL-RSRP, radio propagation loss, or UE-to-UE distance.

[0414] As another method, a threshold for triggering a notification may be set for the SL-RSRP, radio propagation loss, or UE-to-UE distance. For example, the notification may be performed when the measured value or derived value is below or above the threshold. The threshold and the conditions for performing the notification may be determined statically in advance by standards or the like, or may be notified from the transmitting UE to the receiving UE. Such thresholds and conditions are not limited to one, and a plurality of thresholds and conditions may be set. For example, since there are various PC5 communication states depending on the radio propagation environment, the thresholds and conditions can be set according to these PC5 communication states.

[0415] As a method for notifying the notification period, notification request, or threshold and conditions, the method for notifying the transmission power of the transmission signal of PC5 communication may be applied. The same effect can be obtained. As a method for the receiving UE to notify the transmitting UE of the SL-RSRP, radio propagation loss, or UE-to-UE distance, RRC signaling may be used. This is effective when the notification interval is relatively long. Alternatively, MAC signaling may be used. This is effective when the notification interval is relatively short. Alternatively, the SL-RSRP, radio propagation loss, or UE-to-UE distance may be notified by PSFCH as feedback information. This is effective when notifying dynamically. The value to be notified may be the difference from the previous time.

[0416] By doing so, the UE performing PC5 communication can derive the distance between the UEs performing PC5 communication. It becomes possible to derive the range, which is one of the QoS parameter indicators.

[0417] A UE performing PC5 communication discloses another method for deriving the distance between UEs performing PC5 communication. The UE may derive the distance between UEs from the radio propagation delay time of PC5 communication between UEs. Examples of methods for deriving the radio propagation delay time of PC5 communication between UEs are disclosed. When the transmitting UE for deriving the radio propagation delay time in PC5 communication is referred to as UE_tx and the receiving UE is referred to as UE_rx.

[0418] A signal for timing correction is provided. A channel for timing correction may be provided. The signal for timing correction is configured using a predetermined sequence and is mapped to a frequency-time resource having a predetermined frequency band and a predetermined time duration. The frequency unit indicating the resource may be a subcarrier unit, an RB unit, the frequency unit of the subchannel used in SL, a BWP unit, etc. The time unit indicating the resource may be a Ts (= fs, fs; sampling frequency) unit, a sub-symbol unit, a symbol unit, a slot unit, a sub-frame unit, a TTI unit, etc. The frequency-time resource to which the signal for timing correction is mapped may be composed of repetitions of one or more resources, or may be configured periodically.

[0419] The signal for timing correction may be set individually for each UE. For example, the sequence of the signal for timing correction and / or the frequency-time resource of the signal for timing correction may be set for each UE transmitting the signal for timing correction. A UE that receives the signal for timing correction transmitted from a UE in SL can identify the transmitting UE from the sequence and / or the resource. Also, the signal for timing correction may be set individually for each group consisting of one or more UEs. It is possible to identify the group to which the UE transmitting the signal for timing correction belongs.

[0420] Alternatively, the timing correction signal may be commonly set within the transmitting UE in SL communication. By using the timing correction signal commonly set within the UE that is the transmission partner, the UE that is the transmission partner can identify that it is the timing correction signal transmitted to its own UE.

[0421] As another example of the timing correction signal, the timing correction signal may be configured using the identifier of the UE that transmits the signal. The identifier of the UE may be an identifier that can identify the UE. The UE that receives the timing correction signal can identify from which UE the signal was transmitted. Similarly, the timing correction signal may be configured using the group identifier of the group that transmits the signal.

[0422] SRS transmission may be performed between UEs in SL communication. By using SRS to allocate resources for feedback transmission in SL communication, the communication quality of feedback transmission can be improved. The sequence used for SRS and the frequency-time resources to which SRS is mapped may be set individually for each UE or individually for each group.

[0423] SRS may be used as the timing correction signal. By doing so, it is not necessary to separately set resources for the timing correction signal. The resource utilization efficiency can be improved.

[0424] The introduction of PSFCH (Physical Sidelink Feedback CHannel) has been proposed as a channel for transmitting Ack / Nack and CQI in SL communication. The frequency-time resources to which PSFCH is mapped may be set individually for each UE or individually for each group. PSFCH may be used as the timing correction signal. By doing so, it is not necessary to separately set resources for the timing correction signal. The resource utilization efficiency can be improved.

[0425] As a timing correction signal, PRACH in the Uu interface defined between the gNB and the UE may be used. Separately from the PRACH settings for Uu, PRACH settings for PC5 may be provided and used as a timing correction signal. The gNB may notify the UE performing SL communication of the PRACH settings used for SL communication. By doing so, it is not necessary to newly provide a timing correction signal. The configuration for SL communication in the UE can be simplified.

[0426] UE_tx notifies UE_rx of a timing correction signal transmission request. As examples of the information included in the timing correction signal transmission request, (1) to (6) are disclosed below.

[0427] (1) Timing correction signal transmission instruction information.

[0428] (2) Timing information for transmitting the timing correction signal.

[0429] (3) Configuration of the timing correction signal.

[0430] (4) Identifier of UE_tx.

[0431] (5) Identifier of UE_rx.

[0432] (6) Combinations of (1) to (5).

[0433] As described above for (2), information for specifying the transmission timing may be used. For example, a frame number, a slot number, a symbol number, etc. may be used as described above for (2). Also, an offset value may be included in these. Also, the time difference from the timing when the timing correction signal transmission request is received to the timing when the timing correction signal is transmitted may be used as described above for (2). As the unit of the offset value or the time difference, a unit indicating the time resource to which the above-described timing correction signal is mapped may be used. UE_rx can specify the timing for transmitting the timing correction signal.

[0434] As the configuration of the timing correction signal in (3) above, it is advisable to use the aforementioned sequence and the frequency-time resource to which the timing correction signal is mapped. UE_rx can transmit the timing correction signal by using the configuration of the received timing correction signal.

[0435] As the identifier of UE_tx in (4) above, an identifier for identifying UE_tx may be used. UE_rx can identify which UE to transmit the timing correction signal to.

[0436] As the identifier of UE_rx in (5) above, an identifier for identifying UE_rx may be used. The UE that has received the timing correction signal transmission request can determine whether it will transmit the timing correction signal.

[0437] The timing correction signal transmission request may include a plurality of pieces of information. For example, a plurality of pieces of information in (2) above may be notified, or a plurality of pieces of information in (3) above may be notified. UE_rx may transmit a plurality of timing correction signals. Alternatively, UE_rx may select one or more pieces of information from the plurality of pieces of information notified by UE_tx and transmit one or more timing correction signals corresponding to the selected one or more pieces of information.

[0438] The configuration of the timing correction signal may be one or a plurality of configurations. The configuration of the timing correction signal may be statically determined in advance by a standard or the like. Nodes performing V2X communication, such as gNB, UE_tx, and UE_rx, can recognize the configuration of the timing correction signal.

[0439] UE_tx may set the configuration of the timing correction signal. UE_tx may select and set the timing correction signal from a predetermined configuration. The predetermined configuration of the timing correction signal may be the configuration of the timing correction signal for SL. The predetermined configuration of the timing correction signal may be one or more configurations. The predetermined configuration of the timing correction signal may be statically determined in advance by a standard or the like.

[0440] UE_tx notifies UE_rx of the set configuration of the timing correction signal (the setting of the timing correction signal). UE_rx transmits the timing correction signal using the setting of the timing correction signal notified from UE_tx. UE_rx may select one from the settings of the timing correction signal notified from UE_tx and transmit the timing correction signal with the selected setting.

[0441] By UE_tx setting the configuration of the timing correction signal, for example, even when performing SL communication between UEs outside the cell coverage, it becomes possible to set a timing correction signal for UE_rx. Thereby, UE_rx can transmit the timing correction signal.

[0442] gNB may set the configuration of the timing correction signal. gNB may select and set the timing correction signal from a predetermined configuration. The predetermined configuration of the timing correction signal may be the configuration of the timing correction signal for SL. The predetermined configuration of the timing correction signal may be one or more configurations. The predetermined configuration of the timing correction signal may be statically determined in advance by a standard or the like. gNB notifies UE_tx of the set configuration of the timing correction signal (the setting of the timing correction signal).

[0443] UE_tx notifies UE_rx of the configuration of the timing correction signal notified by gNB. UE_tx may notify UE_rx of part or all of the configuration of the timing correction signal notified by gNB. UE_rx transmits the timing correction signal using the setting of the timing correction signal notified by UE_tx. UE_rx may select one from the settings of the timing correction signal notified by UE_tx and transmit the timing correction signal with the selected setting.

[0444] By gNB setting the configuration of the timing correction signal, it becomes possible to set different timing correction signals for different UE_tx. It becomes possible to vary the configuration of the timing correction signal transmitted by UE_rx, and it is possible to reduce the collision of the timing correction signal. At UE_tx, it becomes possible to improve the reception success probability of the timing correction signal from UE_rx.

[0445] UE_rx may set the configuration of the timing correction signal. UE_rx may select and set the timing correction signal from a predetermined configuration. The predetermined configuration of the timing correction signal may be statically determined in advance by a standard or the like.

[0446] By UE_rx setting the configuration of the timing correction signal, it is possible to reduce the signaling for notifying the setting of the timing correction signal from UE_tx to UE_rx, or the signaling for notifying the setting of the timing correction signal from gNB to UE_rx via UE_tx. It is possible to reduce the amount of signaling and the delay time until the transmission of the timing correction signal.

[0447] Disclosed is a method for notifying a signal transmission request for timing correction. When UE_tx notifies UE_rx of a signal transmission request for timing correction, PC5 control signaling in SL communication may be used. Alternatively, RRC signaling in SL communication may be used. UE_tx may notify the signal transmission request for timing correction as an RRC message for SL communication using RRC signaling for SL communication. UE_tx may include the signal transmission request for timing correction in SCCH, which is a logical channel of SL, and transmit it. By doing so, it becomes possible to notify UE_rx of the signal transmission request for timing correction from UE_tx.

[0448] Disclosed is another method for notifying a signal transmission request for timing correction. UE_tx may notify UE_rx of the signal transmission request for timing correction using MAC signaling in SL communication. UE_tx may include the signal transmission request for timing correction in MAC control information and notify it. Since it becomes unnecessary for UE_rx to perform reception processing of the signal transmission request for timing correction by RRC, reception processing can be executed earlier.

[0449] Disclosed is another method for notifying a signal transmission request for timing correction. UE_tx may include the signal transmission request for timing correction in SCI in SL communication and transmit it to UE_rx on PSCCH in SL communication. UE_tx may include the signal transmission request for timing correction in the aforementioned SCI1. UE_tx may include the signal transmission request for timing correction in SCI1 and notify it on PSCCH1. Alternatively, UE_tx may include the signal transmission request for timing correction in SCI2. UE_tx may include the signal transmission request for timing correction in SCI2 and notify it on PSCCH2. By notifying the signal transmission request for timing correction on PSCCH, UE_rx can execute reception processing earlier. Therefore, it becomes possible to set the signal transmission for timing correction from UE_rx earlier.

[0450] Disclose other methods for notifying a signal transmission request for timing correction. UE_tx may transmit a signal transmission request for timing correction to UE_rx using PSCCH and PSSCH in SL communication. For example, among the information included in the signal transmission request for timing correction, UE_tx may include information indicating the signal transmission request for timing correction and the identifier of UE_rx in SCI and transmit it on PSCCH, and transmit other information on PSSCH associated with the PSCCH. When the signal transmission request for timing correction includes a large amount of information, it becomes possible to transmit the large amount of information using PSSCH that can secure a large number of resources.

[0451] The above-described methods for notifying a signal transmission request for timing correction may be combined and used. For example, UE_tx may transmit a part of the information included in the signal transmission request for timing correction by RRC signaling and transmit other information included in PSCCH. For example, UE_tx may transmit the configuration of the signal for timing correction by RRC signaling and transmit other information on PSCCH. By doing so, for example, when setting the configurations of a plurality of signals for timing correction, it becomes possible to transmit a large amount of information by RRC signaling.

[0452] UE_tx may notify the configurations of a plurality of signals for timing correction separately from the configuration of one signal for timing correction that UE_rx actually transmits from among those configurations. Also, in such a case, the above-described combination may be used. For example, UE_tx may notify the configurations of a plurality of signals for timing correction by RRC signaling, and notify the configuration of one signal for timing correction that UE_rx actually transmits from among those configurations together with the signal transmission request information for timing correction on PSCCH. By using RRC signaling, it becomes possible to transmit a large amount of information. By using PSCCH, it becomes possible to perform the process from the notification of the signal transmission request for timing correction to the transmission of the signal for timing correction with low latency.

[0453] The configuration of the timing correction signal may be notified from UE_tx as notification information in SL communication. For example, UE_tx may include the configuration of the timing correction signal in the SL's MIB and transmit it via PSBCH. By doing so, it becomes unnecessary for UE_tx to notify the configuration of the timing correction signal to each of the plurality of UE_rx individually. Thereby, the usage efficiency of signaling resources can be improved. For example, this is effective when the configuration of the timing correction signal is set for each UE_tx.

[0454] UE_rx transmits the timing correction signal at a predetermined timing. UE_rx may use, as the predetermined timing, the timing information for transmitting the timing correction signal received from UE_tx. Alternatively, UE_rx may transmit the timing correction signal at a predetermined timing by using the frequency-time resource indicated by the configuration of the timing correction signal at the earliest timing after receiving the timing correction signal transmission instruction information. Alternatively, the predetermined timing may be a timing statically determined in advance by a standard or the like. Alternatively, the predetermined timing may be the timing set by UE_tx. UE_rx transmits the timing correction signal by using the set configuration of the timing correction signal.

[0455] By doing so, UE_tx can recognize the timing at which UE_rx transmitted the timing correction signal.

[0456] UE_tx receives the timing correction signal transmitted by UE_rx. UE_tx derives the RTT (Round Trip Time) in the SL communication between UE_tx and UE_rx by using the transmission timing of its own UE, the timing at which UE_rx transmitted the timing correction signal, and the timing at which UE_tx received the timing correction signal from UE_rx. UE_tx derives the RTT for each UE_rx.

[0457] When the timing correction signal from UE_rx is transmitted through multipath, it may be used to derive the RTT using the signal received earliest at UE_tx. Alternatively, in the reception at UE_tx, the signal with the strongest received power may be used to derive the RTT.

[0458] UE_tx derives the radio wave propagation delay time between UEs from the RTT specific to UE_rx. The radio wave propagation delay time may be set to 1 / 2 of the RTT. UE_tx derives the distance between UEs using the derived radio wave propagation delay time. By doing so, UE_tx can derive the distance to UE_tx. UE_tx can measure the range to UE_rx.

[0459] In the slot timing at UE_tx, transmission prohibited intervals are provided before and / or after the frequency-time resource to which the timing correction signal is mapped in terms of time. The transmission prohibited intervals may be statically determined in advance, or may be set by gNB and notified to UE_tx. Alternatively, UE_tx may set the transmission prohibited intervals. By doing so, even if the timing correction signal transmitted by UE_rx is shifted from the slot timing at UE_tx due to radio wave propagation delay, UE_tx can receive the timing correction signal.

[0460] There may be multiple UE_rx. Similar time synchronization correction processing may be performed individually for multiple UEs.

[0461] UE_tx may notify UE_rx of candidate configurations for the timing correction signal. UE_rx selects the configuration of the timing correction signal to be used for actual transmission from these candidate configurations. As a result, for example, UE_rx can transmit the timing correction signal using the configuration of the timing correction signal that can be transmitted at the earliest timing after receiving the timing correction signal transmission request. Timing correction can be performed with low latency.

[0462] UE_tx may receive transmissions from UE_rx using all the signal configurations for timing correction selected as candidates. UE_tx can receive the timing correction signal transmitted by UE_rx regardless of which configuration is used. UE_rx may select multiple signal configurations for timing correction from the candidate signal configurations for actual transmission. UE_rx may transmit a timing correction signal using the selected signal configurations for timing correction. By transmitting using multiple signal configurations for timing correction, the success probability of receiving the timing correction signal at UE_tx can be improved. For example, at UE_tx, even if one timing correction signal cannot be received, it is sufficient if another timing correction signal can be received.

[0463] The candidate signal configurations for timing correction may be individually selected for each of the multiple UEs from which UE_tx transmits information regarding time synchronization. It becomes possible to avoid duplication of the signal configurations for timing correction among UEs. As another method, for example, the candidate signal configurations for timing correction may be selected such that some or all of the candidate signal configurations for timing correction are common among multiple UEs. Although duplication of the signal configurations for timing correction may occur among UEs, it becomes possible to improve the usage efficiency of resources.

[0464] UE_rx may retransmit the timing correction signal. UE_rx determines whether to perform retransmission. UE_rx that determines to perform retransmission selects another signal configuration for timing correction from among the candidate signal configurations for timing correction and transmits the timing correction signal of the selected configuration to UE_tx. UE_tx may notify UE_rx of the retransmission timing information in advance. UE_tx may set the retransmission timing for each signal configuration for timing correction. UE_rx may include the retransmission timing information in the notification of the signal configuration for timing correction and notify it. By doing so, for example, UE_tx can cause UE_rx to retransmit the timing correction signal without waiting until the next signal configuration for timing correction.

[0465] Disclosed is a method for UE_rx to determine whether to perform retransmission. When UE_rx cannot receive timing correction information within a predetermined time, UE_rx determines to retransmit the timing correction signal. Alternatively, when UE_rx cannot receive information regarding time synchronization within a predetermined time, UE_rx may determine to retransmit the timing correction signal.

[0466] A timer may be provided to manage the predetermined time. The predetermined time may be determined statically in advance by a standard or the like, or may be set by UE_tx and notified to UE_rx. Alternatively, the predetermined time may be set by gNB, notified from gNB to UE_tx, and then notified from UE_tx to UE_rx. By doing so, when UE_tx fails to receive the timing correction signal, UE_rx can determine to retransmit the timing correction signal. By UE_rx retransmitting the timing correction signal, it is possible to improve the reception success probability at UE_tx.

[0467] As another method, UE_tx may notify UE_rx again of a request for a timing correction signal. UE_tx notifies UE_rx again of a request for a timing correction signal when it fails to receive the timing correction signal from UE_rx at a predetermined timing set by the own UE. UE_tx may notify UE_rx again of a request for a timing correction signal when it fails to receive the timing correction signal from UE_rx at a predetermined timing set by the own UE within a predetermined time. A timer may be provided to manage the predetermined time. For example, it is effective when the timing correction signal is transmitted periodically.

[0468] By doing so, UEs performing PC5 communication can derive the distance between UEs performing PC5 communication. For example, when performing D2D communication in a shielded area within a factory, it is possible to measure the distance between devices without using signals from a base station or GPS.

[0469] Also, for example, a UE possessed by a pedestrian derives the distance to a UE possessed by a vehicle, and when the derived distance is below a predetermined threshold, a notification is sent to the pedestrian. The predetermined threshold may be determined in advance by a standard or the like, or may be determined as a parameter of the V2X service. Alternatively, the predetermined threshold may be set in the V2X application layer. By doing so, the pedestrian can recognize that the vehicle has approached within a predetermined distance and can perform contact avoidance behavior with the vehicle.

[0470] The distance measurement result between UEs performing PC5 communication may be used for UE position derivation. It is preferable to use the distance measurement results between a plurality of UEs. For example, as a UE position derivation method, the radio wave propagation delay between the aforementioned UEs may be used. The radio wave propagation delay information between a plurality of UEs, or the distance information derived from the radio wave propagation delay, is notified between a plurality of UEs. The UE derives its own position using the propagation delay information with a plurality of other UEs. The derived position may be a relative position, for example, a relative position indicating the positional relationship between UEs.

[0471] In the measurement of the radio wave propagation delay information between a plurality of UEs, the measurement timing may be made the same, or the measurement timing may be set as a predetermined time range. The measurement timing is preferably shared in advance between a plurality of UEs. For example, it is preferable to notify the measurement timing in advance between the plurality of UEs to be measured. By doing so, it becomes possible to keep the measurement timing of each UE within a predetermined range. Therefore, the measurement accuracy of the relative positions of a plurality of UEs can be improved.

[0472] For the notification of the radio wave propagation delay information between UEs or the distance information derived from the radio wave propagation delay, PC5-S signaling may be used, or RRC signaling may be used to enable the notification of more position information. Alternatively, MAC signaling may be used to enable earlier notification. Alternatively, PHY signaling may be used. For example, it may be notified on the PSCCH included in the SCI, or may be notified on the PSSCH to enable earlier notification.

[0473] By using distance measurement between UEs, for example, it becomes possible to derive the position of a device in a shielded area within a factory. Also, for example, even when signals from a base station or GPS cannot be obtained inside a tunnel, it becomes possible to derive the position of the UE.

[0474] The distance measurement results between the gNB and the UE may also be used together. By using them in combination with the distance measurement results between UEs, it is possible to improve the position measurement accuracy of the UE.

[0475] The measurement or derivation of QoS parameters may be performed at the V2X application layer. The QoS parameters derived at the V2X application layer may be notified to the AS layer via the V2X layer. The measurement or derivation of QoS parameters may be performed at the V2X layer. The QoS parameters derived at the V2X layer may be notified to the AS layer. The measurement or derivation of QoS parameters may be performed at the AS layer. The layer where the measurement or derivation of QoS parameters is performed may be different for each QoS parameter. It is possible to measure or derive at a layer suitable according to the content of the QoS parameter.

[0476] The UE that has performed the QoS monitor notifies the base station of the QoS monitor result. As a method of notification from the UE to the base station, it is advisable to use communication on Uu. RRC signaling may be used for notification from the UE to the base station. For example, a UE assistance information message may be used. Alternatively, MAC signaling may be used. Alternatively, PUCCH may be used. By doing so, the UE that has performed the QoS monitor can notify the base station of the QoS monitor result. The base station can obtain the QoS monitor result of PC5 communication from the UE performing PC5 communication.

[0477] The base station can recognize whether the PC5 communication meets the required QoS by using the QoS monitoring result of the PC5 communication. The base station can change the scheduling for the PC5 communication by using the QoS monitoring result of the PC5 communication as needed. The base station that has changed the scheduling for the PC5 communication notifies the UE performing the PC5 communication of the changed scheduling information.

[0478] It is disclosed that the number of QoS parameters to be measured may be one or more, or may be a combination of the above-described specific examples of QoS parameters. All of the QoS parameters notified by the UE to the base station may be notified in one signaling. Alternatively, different signaling may be used for each of the one or more measured QoS parameters.

[0479] For example, it may be determined whether to notify using the same signaling or different signaling according to the measurement timing. For example, the RAN node periodically sets the timing for notifying the UE of the QoS monitoring result, and includes the QoS parameters measured between the previous QoS monitoring result notification timing and the next QoS monitoring result notification timing in the same signaling and notifies them.

[0480] The RAN node may perform scheduling again by using the QoS monitoring result in each signaling notified from the UE. By doing so, the QoS monitoring result can be reflected in the scheduling at an early stage.

[0481] It is disclosed that the UE performing the PC5 communication notifies the RAN node of the QoS monitoring result. As another method, information on whether each QoS parameter satisfies a predetermined value may be provided. The UE performing the PC5 communication may notify the RAN node of the information. Alternatively, information on whether each QoS parameter is equal to or greater than a predetermined threshold may be provided, and the UE performing the PC5 communication may notify the RAN node of the information.

[0482] For example, it is effective when a UE performing PC5 communication is acquiring required QoS parameters. The UE performing PC5 communication uses the required value of each QoS parameter as a threshold value, and notifies the RAN node of information on whether the QoS monitoring result is equal to or greater than the threshold value. The predetermined value or threshold value of the QoS parameter may be different from the QoS parameter required value. Flexible settings can be made according to the communication quality and communication environment of the SL.

[0483] By doing so, it is possible to reduce the amount of information on the QoS monitoring result notified by the UE performing PC5 communication to the RAN node.

[0484] FIGS. 28 and 29 are diagrams showing an example of a sequence for performing QoS monitoring of PC5 communication for Embodiment 2. FIGS. 28 and 29 are connected at the position of the boundary line BL2829. FIGS. 28 and 29 show the operations of the UE, RAN node, AMF, SMF, UPF, and PCF. A method for a transmitting UE performing PC5 communication to perform QoS monitoring of PC5 communication is disclosed. In step ST2202, the transmitting UE performing PC5 communication notifies the RAN node (for example, a base station) of the V2X capability. The UE may notify the V2X capability of the PC5 communication. In step ST2203, the RAN node notifies the AMF of the V2X capability received from the UE.

[0485] The UE may notify the V2X capability, for example, by NAS signaling. For example, the UE may include the V2X capability in a message for registration processing and notify it. For example, the UE may include the V2X capability in a message for service request processing and notify it.

[0486] For the notification of the V2X capability, RRC signaling may be used, for example, between the UE and the RAN node. When using RRC signaling, for example, the V2X capability may be notified during RRC connection establishment processing.

[0487] For the notification of V2X capabilities, between the RAN node and the AMF, for example, NG signaling may be used. The NG signaling may be N2 signaling.

[0488] The AMF recognizes that it can provide V2X services using the V2X capabilities received from the UE. The AMF recognizes that it can provide V2X services for PC5 communication using the capabilities of PC5 communication. The UE may notify V2X service provision request information together with the V2X capabilities. The AMF can recognize that the UE clearly requests the provision of V2X services.

[0489] In step ST2204, the AMF notifies the PCF of the V2X capabilities received from the UE. For this notification, for example, the Npcf interface may be used, or the UE Policy Control Create Request message may be used.

[0490] The UE may notify the PCF of a V2X policy provision request. The UE may include the request in a UE policy container (UE Policy Container) that notifies the PCF. The UE may also notify the request to the PCF via the AMF. For the notification from the UE to the AMF, for example, NAS signaling may be used. For example, the UE policy provision request message may be used. For the notification from the AMF to the PCF, for example, the Npcf interface may be used, or the UE Policy Control Update message may be used.

[0491] The PCF that has received the information from the UE performs V2X service authentication using the UE's registration data in step ST2205. Also, the PCF determines to provide a V2X policy to the UE. Further, the PCF determines to provide the V2X service and the corresponding QoS-related information to the UE. The V2X policy may include V2X parameters. The V2X policy may include the V2X service and the corresponding QoS information. The V2X parameters may include QoS-related information. The QoS information may be QoS parameters.

[0492] In step ST2207, the PCF notifies the AMF of the V2X communication-related information. The PCF notifies the V2X service and the corresponding QoS-related information as the V2X communication-related information. The V2X communication-related information may include the V2X policy. The V2X policy may include the V2X service and the corresponding QoS-related information. For example, the V2X parameters may include QoS parameters for each V2X service. The PCF may notify the AMF of the V2X communication-related information using the UE policy provisioning process. For example, it may use the Namf interface or the Communication N1N2 MessageTransfer message.

[0493] In step ST2208, the AMF notifies the RAN node of the V2X communication-related information received from the PCF. N2 signaling may be used for this notification. By doing so, the RAN node can obtain the V2X-related information for the UE. The RAN node can obtain the QoS-related information corresponding to the V2X service. By the RAN node obtaining the V2X-related information for the UE, the RAN node can perform scheduling for the V2X service using PC5 communication.

[0494] The AMF may notify the UE of the V2X communication related information received from the PCF. For example, the AMF may notify the UE of the V2X communication related information in steps ST2208 and ST2209. In step ST2209, the RAN node notifies the UE of the NPN related information and the V2X communication related information. NAS signaling may be used for the notification from the AMF to the UE. UE specific RRC signaling may be used for the notification from the RAN node to the UE. By doing so, the UE can also obtain the V2X communication related information. The UE can obtain the QoS related information corresponding to the V2X service.

[0495] Although it has been shown that the V2X communication related information and the QoS related information are notified by the same signaling, they may be notified by different signaling. By using individual signaling, for example, when there is no update to the V2X related information other than the QoS related information, the notification can be made only by the signaling of the QoS related information. The signaling capacity can be reduced.

[0496] In step ST2211, in the transmitting UE, a V2X service using PC5 communication occurs. The transmitting UE notifies the RAN node of the BSR in step ST2212. The transmitting UE may also notify an SR (Scheduling Request). The RAN node that receives the BSR performs scheduling for PC5 communication for the transmitting UE in step ST2213. At this time, the RAN node performs scheduling for PC5 communication using the QoS related information of PC5 communication obtained in step ST2208. The RAN node may perform scheduling for PC5 communication so as to satisfy the QoS. The RAN node may also use the V2X related information together to perform scheduling for PC5 communication.

[0497] In step ST2214, the RAN node notifies the transmitting UE of the scheduling information for PC5 communication. The transmitting UE uses the scheduling information for PC5 communication received from the RAN node in step ST2214 to perform PC5-S signaling with the receiving UE and establish a link for PC5 communication. For example, in step ST2216, the transmitting UE notifies a PC5 communication request for a predetermined V2X service. The transmitting UE may inform the request. The receiving UE that has received the PC5 communication request for the V2X service notifies the transmitting UE of a PC5 communication acceptance in step ST2217.

[0498] After the establishment of the PC5-S link, in step ST2218, the transmitting UE performs RRC signaling with the receiving UE, for example, mutually notifies the setting information of the AS layer, UE capability information, etc. By doing so, both the transmitting UE and the receiving UE can set the AS layer for PC5 communication.

[0499] In step ST2219, data communication of the V2X service using PC5 communication is performed between the transmitting UE and the receiving UE. By doing so, the PC5 communication performed between the transmitting UE and the receiving UE can be carried out to satisfy the QoS required for the PC5 communication.

[0500] In PC5 communication, the transmitting UE may transmit the BSR to the RAN node multiple times. The BSR may be appropriately transmitted from the PC5-S signaling until the V2X service data transmission or until the PC5 link release. The RAN node, upon receiving the BSR, performs scheduling for PC5 communication using the QoS-related information as described above and notifies the transmitting UE of the scheduling information for PC5 communication.

[0501] Part or all of the QoS for PC5-S signaling, the QoS for PC5 RRC signaling, and the QoS for V2X service data communication may be made different. Different QoS-related information settings may also be used. It becomes possible to make the QoS of each signaling and data transmission different. For example, the RAN node can perform scheduling of PC5 communication so as to satisfy the QoS required for each signaling or data communication. For example, the QoS of the signaling may be set as a lower-latency or higher-quality QoS parameter than data transmission. Malfunctions due to mistransmission of signaling can be reduced.

[0502] Regarding the QoS for PC5-S signaling and / or the QoS for RRC signaling, predetermined QoS-related information may be determined in advance. This information may be determined by a standard or the like. Signaling for notification of QoS-related information can be reduced.

[0503] In step ST2220, the UE performing PC5 communication performs a QoS monitor for PC5 communication. The UE measures QoS transmission-related parameters as the QoS monitor. Here, the case where the UE performing the QoS monitor is the transmitting UE is shown.

[0504] In step ST2221, the transmitting UE notifies the RAN node of the QoS-related parameter measurement result. The transmitting UE may notify the measurement result using the Uu interface. The transmitting UE may use RRC signaling or a message for notifying UE assistant information. In step ST2230, the RAN node performs scheduling for PC5 communication using the QoS-related parameter measurement result obtained in step ST2221.

[0505] For example, when the communication quality of PC5 communication between a transmitting UE and a receiving UE deteriorates, or when the measurement results of QoS-related parameters do not meet the required QoS, the RAN node may perform scheduling to meet the required QoS, such as increasing the resources allocated for PC5 communication. For example, when the communication quality of PC5 communication between the transmitting UE and the receiving UE improves and the measurement results of QoS-related parameters greatly exceed the required QoS, the RAN node may perform scheduling to reduce the extra resources while meeting the required QoS, such as reducing the resources allocated for PC5 communication.

[0506] In this way, by using the measurement results of QoS-related parameters from the transmitting UE and having the RAN node perform scheduling for PC5 communication, it becomes possible to efficiently perform scheduling that meets the desired QoS.

[0507] In step ST2232, the RAN node notifies the transmitting UE of the result information of the PC5 communication scheduling performed in step ST2230. The transmitting UE uses the PC5 communication scheduling information to perform transmission and reception of V2X service data with the receiving UE in step ST2233. Although the transmission and reception of V2X service data are disclosed here, the same applies to the transmission and reception of PC5-S signaling and PC5 RRC signaling.

[0508] In this way, by using the measurement results of QoS-related parameters from the transmitting UE and having the RAN node perform scheduling, it becomes possible to perform PC5 communication that meets the QoS required for PC5 communication between the transmitting UE and the receiving UE.

[0509] Although the transmitting UE performs the QoS monitor, as another method, the receiving UE may perform it. The receiving UE may perform the QoS monitor and notify the transmitting UE of the measurement results of QoS-related parameters. The transmitting UE may notify the RAN node of the measurement results of QoS-related parameters, which are the QoS monitor results of the receiving UE.

[0510] There may be a case where the communication quality in PC5 communication is different between the receiving UE and the transmitting UE. For example, this is the case where there is another UE serving as an interference source in the vicinity of the receiving UE. This other UE interferes with the receiving UE but does not interfere with the transmitting UE. In such a case, the quality of communication from the transmitting UE to the receiving UE deteriorates. By the RAN node obtaining the QoS-related parameter measurement result at the receiving UE, such a situation can be recognized, and scheduling for PC5 communication suitable for such a situation can be implemented.

[0511] Both the QoS monitor at the receiving UE and the QoS monitor at the transmitting UE may be implemented. The RAN node may obtain both QoS-related parameter measurement results. By using both QoS-related parameter measurement results, the RAN node can implement scheduling to meet the QoS required for PC5 communication.

[0512] By the method disclosed in the second embodiment, it is possible to avoid a situation where the QoS required for the V2X service using PC5 communication between UEs continues to be unsatisfied.

[0513] Another method for solving the problem described in the second embodiment is disclosed. The QoS of the UL Uu communication carried out between the base station and the UE performing PC5 communication is used as a substitute for the QoS of the PC5 communication carried out between the UEs performing PC5 communication. The base station may implement a QoS monitor for the UL Uu communication carried out between the base station and the UE performing PC5 communication. As the QoS monitor, one or more of the aforementioned QoS parameters may be measured.

[0514] When the frequency or frequency band used for UL Uu communication is the same as the frequency or frequency band used for PC5 communication, the foregoing method may be applied. When the frequency or frequency band is the same, the radio wave propagation environment is generally the same. Therefore, the communication quality of UL Uu communication carried out between the base station and the UE performing PC5 communication is generally the same as the communication quality of PC5 communication carried out between the UEs performing PC5 communication. Therefore, the QoS monitor result of UL Uu communication is generally the same as the QoS monitor result of PC5 communication between UEs.

[0515] The base station that performs the QoS monitor of UL Uu communication between the UE performing PC5 communication and the base station can determine whether the required QoS is satisfied for the UE by using the QoS monitor result. Furthermore, the base station can change the scheduling for PC5 communication as needed based on the determination result. The base station that changes the scheduling for PC5 communication may notify the UE performing PC5 communication of the changed scheduling information.

[0516] By doing so, it becomes unnecessary to perform a QoS monitor on the UE performing PC5 communication. Also, it becomes unnecessary to notify the base station of the QoS monitor result from the UE performing PC5 communication. It becomes possible to simplify the QoS monitor control and the PC5 communication scheduling process using the QoS monitor result as a system.

[0517] Modification Example 1 of Embodiment 2. In this Modification Example 1, another method for solving the problems disclosed in Embodiment 2 is disclosed.

[0518] Set multiple sets of QoS parameters required for V2X services using PC5 communication. Set multiple QoS parameter sets for V2X services using PC5 communication. A CN-side node that sets QoS parameters for V2X services may set multiple QoS parameter sets for V2X services using PC5 communication. The CN-side node may be, for example, a PCF or a PCC (Policy and Charging Control). Hereinafter, the multiple sets of QoS parameters set may be referred to as a QoS parameter set list.

[0519] One or more QoS parameter sets or a QoS parameter set list may be included in V2X-related information. One or more QoS parameter sets or a QoS parameter set list may be included in V2X policies or V2X parameters. The method for the CN side to provide one or more QoS parameter sets or a QoS parameter set list to the UE may apply the method for providing V2X-related information or the V2X policy providing method disclosed in Embodiment 1 or a modification thereof. By doing so, it is possible to avoid the processing method from becoming different and complicated, and it is possible to reduce malfunction.

[0520] The QoS parameters, QoS parameter sets, or QoS parameter set list may be stored in the CN-side node. The V2X service using PC5 communication may be associated with the QoS parameters, QoS parameter sets, or QoS parameter set list required for the service and stored in the CN-side node. The storage method may appropriately apply the method disclosed in Embodiment 1. The information can be used as needed.

[0521] The UE that has performed the QoS monitor notifies the QoS monitor result to a node having a plurality of QoS parameter sets for the V2X service. For example, if the PCF has a plurality of QoS parameter sets, the UE may notify the QoS monitor result to the PCF. The UE may notify the QoS monitor result to the PCF via the RAN node and the AMF.

[0522] The node that has received the QoS monitor result from the UE may reselect a QoS parameter set for the V2X service from among the plurality of configured QoS parameter sets according to the QoS monitor result.

[0523] The PCF may notify the reselected QoS parameter set to the base station that performs PC5 communication scheduling. The base station receives the reselected QoS parameter set from the PCF. The base station may perform PC5 communication scheduling again for the UE that performs PC5 communication using the QoS parameter. The PCF may also notify the reselected QoS parameter set to the base station via the AMF.

[0524] By doing so, it becomes possible to reselect the QoS parameter set using the QoS monitor result in PC5 communication, and it becomes possible to perform PC5 communication scheduling again using the reselected QoS parameter set. Therefore, it becomes possible to perform scheduling for PC5 communication that matches the communication quality of PC5 communication. It becomes possible to improve the resource utilization efficiency for PC5 communication.

[0525] It is disclosed that a UE that has performed a QoS monitor notifies the QoS monitor result to the PCF. As another method, the UE that has performed the QoS monitor may notify the QoS monitor result to the base station, and the base station may notify the QoS monitor result by the UE to the PCF. The PCF reselects a QoS parameter set according to the QoS monitor result from among a plurality of set QoS parameter sets, and notifies the reselected QoS parameter set to the base station. By doing so, the base station can request the reselection of the QoS parameter set to the CN based on its own judgment.

[0526] For example, the base station can determine whether to change the scheduling for PC5 communication without changing the QoS parameter set or request a change in the QoS parameter set, using the QoS monitor result received from the UE performing PC5 communication. By doing so, the use of signaling to the CN can be appropriately determined according to the QoS monitor result, and thus the amount of signaling with the CN can be reduced.

[0527] As a method for notifying the QoS monitor result from the UE that has performed the QoS monitor to the CN, NAS signaling may be used. The UE notifies the QoS monitor result to the AMF using NAS signaling. The AMF may notify the QoS monitor result to the PCF, for example, using the interface between the AMF and the PCF. The AMF may also request a change in the QoS parameters from the PCF. The AMF may notify the QoS monitor result to the PCF via the SMF. For example, the N11 interface may be used for the notification between the AMF and the SMF, and the N7 interface may be used for the notification between the SMF and the PCF.

[0528] The method disclosed in Embodiment 2 may be appropriately applied to the method by which the UE that has performed the QoS monitor notifies the QoS monitor result to the RAN node. The RAN node may notify the QoS monitor result to the AMF. The N2 signaling may be used for the notification between the RAN node and the AMF. The method for notifying from the AMF to the PCF may apply the aforementioned method.

[0529] Figs. 30 to 32 are diagrams showing an example of a sequence for performing QoS monitoring of PC5 communication for Modification Example 1 of Embodiment 2. Figs. 30 to 32 are connected at the positions of boundary lines BL3031 and BL3132. In the example of Figs. 30 to 32, the QoS-related parameter measurement results of PC5 communication are notified to the CN. In Figs. 30 to 32, the same step numbers are assigned to the steps common to Figs. 28 to 29, and the common explanations are omitted.

[0530] A plurality of QoS parameters for the V2X service using PC5 communication are set. As described above, the QoS parameters consist of one or more types of parameters. Therefore, the QoS parameters may be referred to as a QoS parameter set. In step ST2301, the PCF has a plurality of settings of the QoS parameter set for the V2X service using PC5 communication. Following the V2X communication access authentication using PC5 communication from the transmitting UE, in step ST2306, the PCF selects one from the plurality of settings of the QoS parameter set for PC5 communication.

[0531] The PCF includes the selected one QoS parameter set in the QoS-related information and notifies the RAN node via the AMF in steps ST2207 and ST2208. The PCF may include the selected one QoS parameter set in the V2X communication-related information. In step ST2209, the selected one QoS parameter set may be notified to the UE. Information indicating that a plurality of QoS parameter sets are set for PC5 communication may be provided and notified by the PCF to the AMF and / or the RAN node and / or the UE. The AMF and / or the RAN node and / or the UE can recognize that a plurality of QoS parameter sets are set for PC5 communication.

[0532] In step ST2213, the RAN node performs scheduling for PC5 communication using the one QoS parameter set acquired in step ST2208.

[0533] The transmitting UE performs QoS monitoring in step ST2220. The transmitting UE performs QoS-related parameter measurement and notifies the RAN node of the measurement result in step ST2221. In step ST2322, the RAN node notifies the AMF of the QoS-related parameter measurement result notified by the transmitting UE. In step ST2323, the AMF notifies the PCF of the QoS-related parameters notified by the RAN node. As the notification method, the method of notifying the V2X capability and V2X policy request from the transmitting UE to the PCF described above may be applied. Another message may be provided for notification.

[0534] The PCF that has received the QoS-related parameter measurement result of PC5 communication from the UE appropriately selects one from a plurality of configured QoS parameter sets for PC5 communication in step ST2324. The PCF may select a QoS parameter set for PC5 communication that is different from the QoS parameter set for PC5 communication selected immediately before.

[0535] For example, when the communication quality of PC5 communication between the transmitting UE and the receiving UE deteriorates and the QoS-related parameter measurement result does not meet the required QoS, the PCF selects, for example, a QoS parameter set for PC5 communication that can meet the QoS from among the configured QoS parameter sets for PC5 communication. For example, when the communication quality of PC5 communication between the transmitting UE and the receiving UE improves and the QoS-related parameter measurement result greatly exceeds the required QoS, the PCF selects, for example, a QoS parameter set for PC5 communication suitable for the measured QoS from among the configured QoS parameter sets for PC5 communication.

[0536] By doing so, the PCF can provide the RAN node with a QoS parameter set for PC5 communication suitable for the communication quality of PC5 communication. Therefore, the RAN node can perform scheduling for PC5 communication suitable for the communication quality of PC5 communication.

[0537] In step ST2327, the PCF notifies the AMF of V2X communication related information. The PCF includes, as the V2X communication related information, the QoS parameter set for PC5 communication reselected by the PCF. In step ST2328, the AMF notifies the RAN node of the V2X communication related information received from the PCF. N2 signaling may be used for this notification. By doing so, the RAN node can obtain the QoS parameter set for PC5 communication reselected for the UE. The RAN node can obtain QoS related information for PC5 communication suitable for the QoS monitoring result of PC5 communication. By the RAN node obtaining the QoS parameter set V2X related information for PC5 communication reselected for the UE, the RAN node can perform scheduling for the V2X service using PC5 communication suitable for the QoS monitoring result of PC5 communication.

[0538] The AMF may notify the UE of the QoS parameter set for PC5 communication reselected by the PCF received from the PCF. For example, the AMF may notify the QoS parameter set in steps ST2328 and ST2329. In step ST2329, the RAN node notifies the UE of the QoS parameter set for PC5 communication reselected. By doing so, the UE can also obtain the QoS parameter set for PC5 communication reselected.

[0539] In step ST2331, the RAN node performs scheduling for PC5 communication using the QoS parameter set for PC5 communication reselected obtained in step ST2328. In step ST2232, the RAN node notifies the transmitting UE of the result information of the PC5 communication scheduling performed in step ST2230. The transmitting UE uses the PC5 communication scheduling information to perform transmission and reception of V2X service data with the receiving UE in step ST2233. Here, the transmission and reception of V2X service data are disclosed, but the same applies to the transmission and reception of PC5-S signaling and PC5 RRC signaling.

[0540] In this way, using the QoS monitoring result of the transmitting UE, the PCF selects one from a plurality of sets of PC5 communication QoS parameters that have been set, and provides the selected set of QoS parameters to the RAN node again. As a result, the RAN node can perform scheduling for PC5 communication so as to match the communication quality of PC5 communication. It becomes possible to efficiently schedule the resources used for PC5 communication. It becomes possible to improve the resource utilization efficiency for PC5 communication.

[0541] For the method of notifying one or more sets of QoS parameters or a list of QoS parameter sets from the PCF to the base station, the method for providing V2X-related information or the V2X policy providing process disclosed in Embodiment 1 or a modification thereof may be used.

[0542] The AMF may previously obtain a list of QoS parameter sets from the PCF. The AMF may perform a change of QoS parameters. The UE notifies the QoS monitoring result to the AMF. The UE may notify the QoS monitoring result to the AMF via the base station. The AMF changes the set of QoS parameters using the QoS monitoring result obtained from the UE. The set of QoS parameters to be changed is selected from the list of QoS parameter sets. The AMF may notify the changed set of QoS parameters to the base station. The base station performs PC5 communication scheduling for the UE performing PC5 communication using the changed set of QoS parameters notified from the AMF.

[0543] In this way, by having the AMF previously obtain the set of QoS parameters, it becomes possible to reduce the signaling between the AMF and the PCF and the processing in the PCF when changing the QoS parameters.

[0544] The SMF may obtain a QoS parameter set list from the PCF in advance. The SMF may also perform changes to the QoS parameters. The UE notifies the SMF of the QoS monitoring result. The UE may also notify the SMF of the QoS monitoring result via the base station and the AMF. The SMF changes the QoS parameter set using the QoS monitoring result obtained from the UE. The QoS parameter set to be changed is selected from the QoS parameter set list. The SMF may notify the base station of the changed QoS parameter set. The SMF may also notify the base station of the changed QoS parameter set via the AMF. The base station performs PC5 communication scheduling for the UE performing PC5 communication using the changed QoS parameter set notified from the SMF.

[0545] By the method disclosed in the first modification example of the second embodiment, it is possible to avoid a situation where the QoS required for the V2X service using PC5 communication between UEs continues to be unsatisfied.

[0546] Modification example 2 of the second embodiment. A UE performing PC5 communication may perform PC5 communication scheduling. In such a case, the resources used for PC5 communication scheduling are selected from a resource pool. The resource pool may be notified by the base station. A method for solving the problems disclosed in the second embodiment is disclosed for the case where a UE performing PC5 communication performs PC5 communication scheduling using the resource pool notified by the base station.

[0547] Multiple resource pools used in the V2X service using PC5 communication are configured. For the V2X service using PC5 communication, multiple resource pools are configured. The CN-side node that configures the resource pool for the V2X service may configure multiple resource pools for the V2X service using PC5 communication. The CN-side node may be, for example, a PCF or a PCC (Policy and Charging Control). Hereinafter, the multiple configured resource pools may be referred to as a resource pool list.

[0548] One or more resource pools or a resource pool list may be configured together with the QoS parameters for the V2X service. A rule for deriving a resource pool from the service requirements of the V2X service using PC5 communication may be configured. A rule for deriving QoS parameters from the service requirements of the V2X service using PC5 communication and a rule for deriving a resource pool from the requirements may be configured within the same rule.

[0549] One or more resource pools or a resource pool list used in the V2X service using PC5 communication may be included in the V2X-related information. One or more resource pools or a resource pool list used in the V2X service using PC5 communication may be included in the V2X-related information together with the QoS parameters for the V2X service. These providing methods and storage methods for the CN-side node may appropriately apply the methods disclosed in Embodiment 2 or Modification Example 1 of Embodiment 2. The same effects can be obtained.

[0550] The UE that has performed the QoS monitor notifies the QoS monitor result to a node having multiple resource pools for the V2X service. For example, when the PCF has multiple resource pools, the UE may notify the QoS monitor result to the PCF. The node that has received the QoS monitor result from the UE may reselect the resource pool for the V2X service from among the multiple configured resource pools according to the QoS monitor result.

[0551] The PCF may notify the base station that notifies the PC5 communication resource pool of the reselected resource pool. The PCF may also notify the base station that has been notified of the UE's QoS monitoring result of the reselected resource pool. The base station receives the reselected resource pool from the PCF. The base station notifies the resource pool. The UE performing PC5 communication may perform PC5 communication scheduling again using the reselected resource pool from the base station. The PCF may notify the reselected resource pool to the base station via the AMF.

[0552] In this way, for the method of setting multiple resource pools and changing the resource pool based on the QoS monitoring result, the method disclosed in Modification Example 1 of Embodiment 2 may be appropriately applied. In the method disclosed in Modification Example 1 of Embodiment 2, the QoS parameter set may be replaced with a resource pool. Also, the PC5 communication scheduling performed by the base station for the UE performing PC5 communication may be replaced with the notification of the PC5 communication resource pool.

[0553] By doing so, it becomes possible to reselect the resource pool used for PC5 communication using the QoS monitoring result in PC5 communication, and it becomes possible to perform PC5 communication scheduling again using the reselected resource pool. Therefore, it becomes possible to perform scheduling for PC5 communication that matches the communication quality of PC5 communication. It becomes possible to improve the resource usage efficiency for PC5 communication.

[0554] A priority may be set for the QoS parameter set. A priority may be set for the resource pool. The QoS parameter set or the resource pool may be reselected according to the priority. For example, selection and reselection may be performed from the QoS parameter set or the resource pool with a higher priority. By setting the priority in this way, it becomes possible to control the QoS parameter set and the resource pool to be used.

[0555] For example, you may combine the aforementioned QoS parameter set, the method for reselecting the resource pool, and the priority. For example, when the QoS-related parameter measurement result does not meet the required QoS, select a QoS parameter set for PC5 communication that can meet the QoS from the set of QoS parameter sets for PC5 communication that are set. When there are multiple QoS parameter sets for PC5 communication as options, select the QoS parameter with the highest priority from them. When the communication quality of the PC5 communication between the transmitting UE and the receiving UE becomes good and the QoS-related parameter measurement result greatly exceeds the required QoS, select a QoS parameter set for PC5 communication suitable for the measured QoS from the set of QoS parameter sets for PC5 communication that are set. When there are multiple QoS parameter sets for PC5 communication as options, select the QoS parameter with the highest priority from them.

[0556] By doing so, it becomes possible to perform PC5 communication with the desired QoS, and it also becomes possible to improve the usage efficiency of the resources used for PC5 communication.

[0557] Ranks may be provided. One or more QoS parameter sets or resource pools are set for each rank. It is advisable to reselect the QoS parameter set or resource pool within the selected rank according to the QoS monitor result. By doing so, flexibility can be obtained in reselection compared to control by priority.

[0558] The priority and rank may be set for each UE. The priority and rank may be set for each UE using PC5 communication. The priority can be set according to the capabilities of each UE, the location of each UE, and the communication environment of each UE. As another method, the priority and rank may be set for each V2X service using PC5 communication. It can be set according to the content and required conditions of the service.

[0559] Even when a UE performing PC5 communication performs PC5 communication scheduling using a resource pool notified from a base station by the method disclosed in Modified Example 2 of Embodiment 2, it is possible to avoid a situation where the QoS required for the V2X service using PC5 communication between UEs continues to be unsatisfied.

[0560] Modified Example 3 of Embodiment 2. A UE performing PC5 communication may perform PC5 communication scheduling. In such a case, a QoS parameter set corresponding to the V2X service used for PC5 communication scheduling is configured in the UE in advance. A method for solving the problems disclosed in Embodiment 2 is disclosed for the case where a UE performing PC5 communication performs PC5 communication scheduling using the QoS parameter set configured in the UE in advance.

[0561] When a UE performing PC5 communication enters the coverage of a base station, the UE performs a change of the QoS parameter set via the base station. The change of the QoS parameter set may be performed using the V2X policy update process between the UE performing PC5 communication and the PCF. The method for performing the QoS monitor may be the method disclosed in Embodiment 2. The method for setting a plurality of QoS parameter sets for PC5 communication and the method for changing the QoS parameter set using the V2X policy update process between the UE and the PCF may be the method for providing V2X-related information or the V2X policy providing method disclosed in Embodiment 1 or its modified example. By doing so, it is possible to avoid the processing method becoming different and complicated, and it is possible to reduce malfunction.

[0562] A resource pool corresponding to the V2X service used for PC5 communication scheduling is configured in the UE in advance. The same applies to the case where a UE performing PC5 communication performs PC5 communication scheduling using the resource pool configured in the UE in advance.

[0563] When a UE performing PC5 communication enters the coverage of a base station, it performs a change of the resource pool via the base station. The change of the resource pool may be performed using V2X policy update processing between the UE performing PC5 communication and the PCF. As for the method of performing the QoS monitor, the method disclosed in Embodiment 2 may be applied. As for the method of setting a plurality of resource pools for PC5 communication and the method of changing the resource pool using V2X policy update processing between the UE and the PCF, the method of providing V2X-related information or the method of providing V2X policies disclosed in Embodiment 1 or a modification thereof may be applied. By doing so, it is possible to avoid the processing method from becoming different and complicated, and it is possible to reduce malfunction.

[0564] Both the change of the QoS parameter set and the change of the resource pool described above may be performed together, or only one of them may be performed. The UE may determine which change method to perform, or the CN-side node may determine. The PCF as the CN-side node may determine. The CN-side node may determine using the QoS monitor result notified from the UE.

[0565] The UE performing PC5 communication may perform scheduling for PC5 communication again using the changed QoS parameter set and / or resource pool. By doing so, when the UE performing PC5 communication enters the coverage of the base station, it becomes possible to perform a change of the QoS parameter set via the base station. For example, even when the UE is performing PC5 communication outside the coverage and the QoS for the V2X service is no longer satisfied, when the UE enters the coverage of the base station, it becomes possible to perform a change of the QoS parameter set via the base station. Therefore, it is possible to avoid a state where the QoS for the V2X service is not satisfied for a long time.

[0566] Other methods are disclosed. A plurality of QoS parameter sets and / or a plurality of resource pools for V2X services are acquired by the UE in advance. A UE performing PC5 communication acquires a QoS parameter set list and / or a resource pool list from a CN-side node having the QoS parameter set list and / or the resource pool list in advance. The CN-side node having the QoS parameter set list and / or the resource pool list provides the QoS parameter set list and / or the resource pool list to the UE performing PC5 communication in advance.

[0567] For the process of providing the QoS parameter set list and / or the resource pool list between the UE and the CN-side node having the QoS parameter set list and / or the resource pool list, the method described above may be appropriately applied.

[0568] A UE performing PC5 communication implements a QoS monitor and changes the QoS parameter set and / or the resource pool using the QoS monitor result. The QoS parameter set and / or the resource pool to be changed is selected from the QoS parameter set list and / or the resource pool list acquired by the UE. The UE performing PC5 communication implements PC5 communication scheduling using the reselected QoS parameter set and / or resource pool.

[0569] FIGS. 33 and 34 are diagrams showing a first example of a sequence for performing QoS monitoring of PC5 communication for Modification Example 3 of Embodiment 2. FIGS. 33 and 34 are connected at the position of the boundary line BL3334. FIGS. 33 and 34 show an example in which the transmitting UE performs PC5 communication scheduling. In FIGS. 33 and 34, the same step numbers are assigned to the steps common to FIGS. 30 to 32, and the common description is omitted.

[0570] A plurality of QoS parameters for V2X services using PC5 communication are notified from the PCF to the UE.

[0571] In steps ST2407, ST2408, and ST2409, the PCF notifies the UE of a plurality of QoS parameter sets for PC5 communication. The PCF may include the plurality of QoS parameter sets for PC5 communication in the QoS-related information and then notify. By doing so, the UE can obtain the plurality of QoS parameter sets for PC5 communication.

[0572] In step ST2413, the UE selects one from the plurality of QoS parameter sets for PC5 communication obtained in step ST2409, and performs scheduling for PC5 communication using the selected QoS parameter set.

[0573] The transmitting UE performs a QoS monitor in step ST2220. The transmitting UE performs QoS-related parameter measurement. In step ST2425, the transmitting UE appropriately re-selects one from the plurality of QoS parameter sets for PC5 communication that are set, using the QoS-related parameter measurement result. The transmitting UE may select a QoS parameter set for PC5 communication that is different from the QoS parameter set for PC5 communication selected immediately before.

[0574] For example, when the communication quality of PC5 communication between the transmitting UE and the receiving UE deteriorates, or when the QoS-related parameter measurement result does not meet the required QoS, the transmitting UE selects, for example, a QoS parameter set for PC5 communication that can meet the QoS from among the QoS parameter sets for PC5 communication that are set. For example, when the communication quality of PC5 communication between the transmitting UE and the receiving UE improves and the QoS-related parameter measurement result greatly exceeds the required QoS, the transmitting UE selects, for example, a QoS parameter set for PC5 communication that is suitable for the measured QoS from among the QoS parameter sets for PC5 communication that are set.

[0575] The transmitting UE performs PC5 communication scheduling using the reselected QoS parameter set for PC5 communication in step ST2431. In this way, by the PCF notifying the transmitting UE of multiple QoS parameter sets for PC5 communication, the transmitting UE can use the monitored QoS monitoring results to re - perform the scheduling for PC5 communication so as to match the communication quality of PC5 communication. It becomes possible to efficiently schedule the resources used for PC5 communication. It becomes possible to improve the resource utilization efficiency for PC5 communication.

[0576] As described above, a plurality of QoS parameter sets and / or a plurality of resources for the V2X service using PC5 communication may be set or stored in the CN - side node. As the CN - side node, for example, PCF or PCC is disclosed. Not limited to this, the CN - side node may be AMF, SMF, or UPF. A plurality of QoS parameter sets and a plurality of resources for the V2X service using PC5 communication may be set or stored in different CN - side nodes.

[0577] The UE performing PC5 communication performs QoS monitoring and notifies the QoS monitoring results to the CN - side node. The CN - side node re - selects QoS parameter sets and / or resources using the QoS monitoring results from the UE. The CN - side node notifies the re - selected QoS parameter sets and / or resources to the UE. The UE performs PC5 communication scheduling using the notified QoS parameter sets and / or resources.

[0578] By setting or storing a plurality of QoS parameter sets and / or a plurality of resources for the V2X service using PC5 communication in the CN-side node, e.g., AMF, SMF, UPF, the access time from the UE to the CN-side node can be shortened. The UE can perform PC5 communication scheduling earlier using the reselected QoS parameter set and / or resources. Therefore, the period during which the QoS required for the V2X service using PC5 communication is not satisfied can be shortened.

[0579] In the foregoing, it has been disclosed that a plurality of QoS parameter sets and / or a plurality of resources for the V2X service using PC5 communication are set or stored in the CN-side node. In contrast, a plurality of QoS parameter sets and / or a plurality of resources for the V2X service using PC5 communication may be set or stored in the RAN node. The UE performing PC5 communication performs QoS monitoring and notifies the RAN node of the QoS monitoring result. The RAN node reselects the QoS parameter set and / or resources using the QoS monitoring result from the UE. The RAN node notifies the UE of the reselected QoS parameter set and / or resources. The UE performs PC5 communication scheduling using the notified QoS parameter set and / or resources.

[0580] By doing so, the period during which the QoS required for the V2X service using PC5 communication is not satisfied can be further shortened.

[0581] FIG. 35 and FIG. 36 are diagrams showing a second example of a sequence for performing QoS monitoring of PC5 communication for Modification Example 3 of Embodiment 2. FIG. 35 and FIG. 36 are connected at the position of the boundary line BL3536. FIGS. 35 and 36 show an example in which the RAN node notifies resources for PC5 communication. FIGS. 35 and 36 show an example in which the UE performs PC5 communication scheduling. In FIGS. 35 and 36, the same step numbers are assigned to the steps common to FIGS. 30 to 32 and FIGS. 33 to 34, and the common descriptions are omitted.

[0582] A plurality of QoS parameters for the V2X service using PC5 communication are notified from the PCF to the RAN node.

[0583] In steps ST2407 and ST2408, the PCF notifies a plurality of QoS parameter sets for PC5 communication to the RAN node. The PCF may notify a plurality of QoS parameter sets for PC5 communication included in QoS-related information. By doing so, the RAN node can acquire a plurality of QoS parameter sets for PC5 communication.

[0584] In step ST2613, the RAN node selects one from the plurality of QoS parameter sets for PC5 communication acquired in step ST2408. The RAN node sets resources for PC5 communication using the selected QoS parameter set, and in step ST2615, notifies the UE of the resources for PC5 communication. The RAN node may notify the resources for PC5 communication included in PC5-related information. The resources for PC5 communication may be resource pool information.

[0585] The transmitting UE performs PC5 communication scheduling using the PC5 communication-related information in step ST2617.

[0586] The transmitting UE performs a QoS monitor in step ST2220. The transmitting UE performs QoS-related parameter measurements. In step ST2221, the transmitting UE notifies the RAN node of the QoS-related parameter measurement results. In step ST2626, the RAN node appropriately reselects one from a plurality of sets of QoS parameters for PC5 communication that are set, using the QoS-related parameter measurement results notified from the transmitting UE. The RAN node may select a set of QoS parameters for PC5 communication that is different from the set of QoS parameters for PC5 communication selected immediately before.

[0587] Regarding the method for selecting QoS parameters for PC5 communication, the above-described method disclosed for the case where the PCF or the UE selects QoS parameters for PC5 communication may be applied. In step ST2626, the RAN node sets resources for PC5 communication using the set of QoS parameters for PC5 communication reselected. By doing so, the RAN node can set resources for PC5 communication suitable for the QoS of PC5 communication.

[0588] In step ST2628, the transmitting UE receives the reconfigured PC5 communication-related information and obtains the RP for PC5 communication. In step ST2630, the transmitting UE performs scheduling for PC5 communication using the reconfigured PC5 communication-related information. In this way, the PCF notifies the RAN node of a plurality of sets of QoS parameters for PC5 communication, the RAN node sets PC5 communication resources suitable for the selected set of QoS parameters for PC5 communication, and notifies the set PC5 communication resources. As a result, the transmitting UE can perform scheduling for PC5 communication using the reconfigured PC5 communication resources.

[0589] Therefore, it becomes possible to perform scheduling for PC5 communication again so as to match the communication quality of PC5 communication. It becomes possible to efficiently schedule the resources used for PC5 communication. It becomes possible to improve the resource utilization efficiency for PC5 communication.

[0590] The method by which the PCF notifies the RAN node of a plurality of QoS parameter sets for PC5 communication is also applicable when the RAN node performs scheduling for PC5 communication. Similarly, it is possible to improve the resource utilization efficiency for PC5 communication.

[0591] Note that it has been disclosed to set or store a plurality of QoS parameter sets and / or a plurality of resources for the V2X service using PC5 communication in the CN-side node or the RAN node. As another example, a node having a plurality of QoS parameter sets and / or a plurality of resources for the V2X service using PC5 communication may be provided in advance to other nodes, for example, the CN-side node or the RAN node. The plurality of QoS parameter sets and / or the plurality of resources may be provided in response to the request of the other node. By being provided in advance to the other node, the same effect can be obtained.

[0592] Another method is disclosed. A plurality of QoS parameter sets and / or a plurality of resource pools for the V2X service may be configured in the UE in advance. It is advisable to store in the UE a plurality of QoS parameter sets and / or a plurality of resource pools for the V2X service. The plurality of QoS parameter sets and / or the plurality of resource pools for the V2X service are preferably stored in the UE in advance, rather than being provided through the provisioning process between the UE and the PCF. For example, a plurality of QoS parameter sets and / or a plurality of resource pools for the V2X service may be stored in the (U)SIM or CICC.

[0593] The UE performing PC5 communication implements a QoS monitor and changes the QoS parameter set and / or resource pool using the QoS monitor result. The QoS parameter set and / or resource pool to be changed is selected from a list of QoS parameter sets and / or a list of resource pools pre-configured in the UE. The UE performing PC5 communication performs PC5 communication scheduling using the re-selected QoS parameter set and / or resource pool.

[0594] FIG. 37 is a diagram showing a third example of a sequence for performing QoS monitoring of PC5 communication for Modification Example 3 of Embodiment 2. FIG. 37 shows an example in which the transmitting UE performs PC5 communication scheduling. In FIG. 37, steps common to FIGS. 33 to 34 are assigned the same step numbers, and common descriptions are omitted.

[0595] A plurality of QoS parameter sets for PC5 communication may be pre-configured in the UE. The transmitting UE selects one from the plurality of QoS parameter sets for PC5 communication pre-configured in the UE and performs PC5 communication scheduling using the selected QoS parameter set.

[0596] In step ST2510, a plurality of QoS parameter sets for PC5 communication are configured in the transmitting UE. In step ST2512, the transmitting UE selects one from the plurality of QoS parameter sets for PC5 communication set in the UE. In step ST2213, the transmitting UE performs scheduling for PC5 communication using the selected QoS parameter set.

[0597] The transmitting UE performs a QoS monitor in step ST2220. The transmitting UE performs QoS-related parameter measurements. The transmitting UE re-selects, as appropriate, one from among a plurality of configured QoS parameter sets for PC5 communication using the QoS-related parameter measurement results in step ST2530. The transmitting UE may select a QoS parameter set for PC5 communication that is different from the QoS parameter set for PC5 communication selected immediately before.

[0598] The method for selecting QoS parameters for PC5 communication may apply the foregoing method. The transmitting UE performs scheduling for PC5 communication using the re-selected QoS-related information for PC5 communication in step ST2531. By doing so, the transmitting UE can re-perform scheduling for PC5 communication so as to match the communication quality of PC5 communication. It becomes possible to efficiently schedule the resources used for PC5 communication. It becomes possible to improve the resource utilization efficiency for PC5 communication.

[0599] By doing so, even if the UE is performing PC5 communication outside the coverage and the QoS for the V2X service is no longer satisfied, the UE can perform a change in the QoS parameter set. Therefore, it becomes possible to avoid a situation where the QoS for the V2X service continues to be unsatisfied.

[0600] The UE performing PC5 communication may be a UE that relays PC5 communication and PC5 communication, or may be a UE that relays Uu communication and PC5 communication. For these UEs, a QoS parameter set and / or a plurality of resource pools may be provided. When the UE performs relaying, it becomes possible to re-schedule PC5 communication based on the QoS monitor result during relaying.

[0601] An example is disclosed in which a UE performing PC5 communication monitors QoS and notifies the RAN node or the CN node of the QoS monitoring result. Instead of the QoS monitoring result, information indicating whether the QoS value is satisfied may be provided. A UE performing PC5 communication may monitor QoS and notify the RAN node or the CN node of information indicating whether the QoS value is satisfied. By appropriately applying the foregoing method, similar effects can be obtained.

[0602] Also, as another method, a UE performing PC5 communication may notify the RAN node of a rescheduling request. The request may be a rescheduling request for QoS improvement. A UE performing PC5 communication monitors QoS and determines whether to notify a rescheduling request using the QoS monitoring result.

[0603] For example, if the QoS monitoring result does not meet the QoS required for the V2X service using PC5 communication, or if it meets but is within a predetermined range, the UE decides to notify a rescheduling request. Otherwise, the UE decides not to notify a rescheduling request.

[0604] If a UE performing PC5 communication decides to notify a rescheduling request, it notifies the RAN node of the rescheduling request. The RAN node that receives the request performs rescheduling so that, for example, the QoS regarding the UE is improved, and notifies the UE of the information.

[0605] By doing so, it becomes possible to improve the QoS of the V2X service using PC5 communication.

[0606] The rescheduling request may be a rescheduling request for QoS relaxation. For example, when a UE performing PC5 communication determines that the QoS monitoring result significantly exceeds the required QoS, it may notify the RAN node of a rescheduling request for QoS relaxation. The RAN node that receives the request performs rescheduling so that the QoS for the UE is relaxed and notifies the UE of the information.

[0607] By doing so, it becomes possible to relax the QoS of the V2X service using PC5 communication. It becomes possible to relax the QoS within a range that satisfies the QoS and redirect resources to other UEs. It becomes possible to improve the resource usage efficiency of the system.

[0608] As another method, a UE performing PC5 communication may notify the NW node of a request for re-provisioning of a QoS parameter set and / or a resource pool. The request may be a re-provisioning request for QoS improvement. A UE performing PC5 communication performs QoS monitoring and determines whether to notify a re-provisioning request using the QoS monitoring result.

[0609] For example, when the QoS monitoring result does not meet the QoS required for the V2X service using PC5 communication or is within a predetermined range although it meets the requirement, the UE decides to notify a re-provisioning request. Otherwise, the UE decides not to notify a re-provisioning request.

[0610] When a UE performing PC5 communication decides to notify a re-provisioning request, it notifies the NW node of the re-provisioning request. The NW node that receives the request, for example, re-selects a QoS parameter set and / or a resource pool so that the QoS for the UE is improved and re-provides the information on the re-selected QoS parameter set and / or resource pool to the UE.

[0611] By doing so, it becomes possible to improve the QoS of the V2X service using PC5 communication.

[0612] The re-provisioning request may also be a re-provisioning request for QoS relaxation. For example, when the UE performing PC5 communication determines that the QoS monitoring result significantly exceeds the required QoS, it may notify the CN node of a re-provisioning request for QoS relaxation. The CN node that receives the request re-selects the QoS parameter set and / or the resource pool so that the QoS for the UE is relaxed, and re-provides the information on the re-selected QoS parameter set and / or the resource pool to the UE.

[0613] By doing so, it becomes possible to relax the QoS of the V2X service using PC5 communication. It is possible to relax the QoS within a range that satisfies the QoS and redirect resources to other UEs. It is possible to improve the resource utilization efficiency of the system.

[0614] In this way, instead of notifying the QoS monitoring result, by notifying a re-scheduling request or a re-provisioning request, the amount of information required for the notification can be reduced. Notification can be made with a small number of bits.

[0615] If there is no QoS parameter set and / or resource pool to re-select, it may be assumed that the PC5 communication ends. The node that performs the re-selection may initiate the release of the PC5 communication. As the release of the PC5 communication, the release of the resources at the AS layer may be performed. The transmitting UE that has been triggered to release the PC5 communication releases its own resources and may also notify the receiving UE of a request to release the resources at the AS layer. The receiving UE that receives the release request releases the resources at the AS layer. The receiving UE may notify the transmitting UE of the completion of the release of the resources at the AS layer. The transmitting UE may perform the release of its own resources upon receiving the notification.

[0616] For the start notification of PC5 communication resource release, the request notification of resource release, and the completion notification of resource release, RRC signaling may be used. The misreception of the notification can be reduced, and a large amount of information can be notified. As another method, MAC signaling may be used. The misreception of the notification can be reduced, and the notification can be made earlier. As another method, PHY signaling may be used. The notification can be made even earlier. These notification methods may be varied according to the notification content. According to the notification content, the above-mentioned effects can be obtained.

[0617] As the release of PC5 communication, the release of the PC5-S link may be performed. The release of the PC5-S link may be performed together with the release of the resources in the AS layer. The transmitting UE that has been activated to release PC5 communication may perform the release of its own PC5-S link and may notify the receiving UE of the request for the release of the PC5-S link. As the release process of the PC5-S link, the settings in the V2X layer, for example, the mapping of the application identifier from the application layer in the V2X service and the identifier used in L2 are released.

[0618] The receiving UE that has received the release request performs the release of the PC5-S link. The receiving UE may notify the transmitting UE of the completion of the release of the PC5-S link. The transmitting UE may perform the release of its own PC5-S link upon receiving the notification.

[0619] By doing so, even when the QoS parameter set and / or the resource pool to be reselected disappear, the UE performing PC5 communication can reduce wasteful processes such as continuously holding the resources for PC5 communication. The utilization efficiency of radio resources can be improved. Also, wasteful processes in the UE can be reduced, and the power consumption of the UE can be reduced.

[0620] Modification Example 4 of Embodiment 2. In 3GPP, groupcast is being considered as a method of PC5 communication. Groupcast is a method of performing PC5 communication between UE groups. In a UE group, a UE serving as a leader (leader UE) and other UEs (member UEs) are provided, and PC5 communication is performed between the leader UE and the member UEs or between the member UEs. For the PC5 communication between the leader UE and the member UEs, the method described above may be applied. The same effect can be obtained.

[0621] For the PC5 communication between the member UEs, the leader UE performs PC5 communication scheduling so as to satisfy the QoS required for the V2X service using the PC5 communication between the member UEs. The method described above discloses a solution method when a UE performing PC5 communication performs PC5 communication scheduling. Therefore, when a UE that does not perform PC5 communication (leader UE) performs PC5 communication scheduling between UEs that perform PC5 communication (member UEs), the above-described solution method cannot be simply applied.

[0622] For example, when the quality of the PC5 communication between the member UEs deteriorates and the required QoS cannot be satisfied, the leader UE that performs the PC5 communication scheduling between the member UEs cannot recognize the deterioration of the PC5 communication quality and will continue to perform the same scheduling. Therefore, the situation where the QoS required for the PC5 communication between the member UEs is not satisfied will continue.

[0623] This modification example 4 discloses a method for solving such problems.

[0624] The leader UE may perform V2X policy providing processing with respect to the CN. The leader UE can acquire V2X communication related information from the CN. As this method, the method disclosed in Modification Example 3 of Embodiment 2 may be applied. The PCF may provide a plurality of QoS parameter sets or one QoS parameter set to the UE. The leader UE performs scheduling for the PC5 communication between the member UEs using the V2X policy provided from the CN.

[0625] The V2X policy for PC5 communication between member UEs within a group may be the same as the communication between the leader UE and the transmitting member UE. By making the V2X policies for PC5 communication within the group identical, the PC5 communication processing within the group can be simplified, and member - to - member PC5 communication can be carried out with low latency.

[0626] The V2X policy for PC5 communication between member UEs within a group may be different from the communication between the leader UE and the transmitting member UE. The transmitting member UE may perform, via the leader UE, authentication of the V2X service using PC5 communication and / or the V2X policy provisioning process for the PCF. The leader UE performs the V2X policy provisioning process for the transmitting member UE for the PCF via the RAN node and the AMF. The V2X policy provisioning process between the leader UE and the PCF may apply the method disclosed in Modification Example 3 of Embodiment 2.

[0627] The leader UE may establish a PC5 communication link with member UEs within the group in advance. The transmitting member UE may request the leader UE for authentication of the V2X service using PC5 communication and / or provision of the V2X policy. The transmitting member UE can initiate a request for authentication of the V2X service using PC5 communication and / or provision of the V2X policy via the leader UE.

[0628] Resources for PC5 communication between UEs within the group may be preset. This setting may be determined statically by a standard or the like. Alternatively, this setting may be pre - configured in the UEs within the group. Until the V2X policy provisioning process is carried out, the UEs within the group may perform PC5 communication using these resources. The leader UE performs scheduling for PC5 communication between member UEs using these resources. For example, even when a member UE exists outside the cell coverage, it is possible to use the V2X policy for PC5 communication.

[0629] By doing so, the UEs within the group can use the V2X policy for PC5 communication, including the member UEs. PC5 communication becomes possible within the group, for example, between the leader UE and the member UEs or between the member UEs.

[0630] The UE that performs PC5 communication between member UEs monitors the QoS in PC5 communication. The UE that performs PC5 communication between member UEs may be the transmitting UE or the receiving UE. The PC5 communication between member UEs may be broadcast, group cast, or unicast. The UE may measure QoS parameters as the QoS monitor. The QoS monitor may be performed for all QoS parameters or for some of them.

[0631] The member UE that performs the QoS monitor notifies the QoS monitor result to the leader UE. The UE notifies the measurement result of the QoS parameters performed as the QoS monitor. By doing so, the leader UE that schedules the PC5 communication between member UEs can recognize the actual QoS of the PC5 communication.

[0632] The leader UE can determine whether the PC5 communication between member UEs meets the required QoS by using the QoS monitor result of the PC5 communication between member UEs notified by the member UEs. The leader UE can change the scheduling for the PC5 communication between member UEs by using the QoS monitor result of the PC5 communication between member UEs as needed. The leader UE notifies the member UEs of the scheduling information for the PC5 communication between member UEs after the change.

[0633] For these methods, the methods disclosed in the foregoing embodiments or modifications may be appropriately applied. For example, the base station in Embodiment 2 may be replaced with the leader UE, and the UE that performs PC5 communication may be replaced with the member UE that performs PC5 communication. By doing so, it becomes possible to obtain the desired QoS for the V2X service using the PC5 communication between member UEs.

[0634] Figure 38 is a diagram showing an example of a sequence for performing QoS monitoring of PC5 communication for Modification Example 4 of Embodiment 2. Figure 38 shows an example in which group cast communication is performed using PC5 communication. Figure 38 shows an example in which a leader UE within a group performs scheduling for PC5 communication among member UEs. Figure 38 shows a leader UE within a group, a transmitting member UE that performs PC5 communication, and a receiving member UE.

[0635] In step ST2701, the leader UE performs scheduling for PC5 communication between the leader UE and the transmitting UE using QoS-related information. From step ST2702 to step ST2704, establishment of a PC5 link and PC5 RRC signaling are performed between the leader UE and the transmitting member UE. When a V2X service using PC5 communication between member UEs occurs in the transmitting member UE, the transmitting member UE notifies the leader UE of a scheduling request for PC5 communication between member UEs in step ST2705. The transmitting member UE may include this request in the RRC signaling of step ST2704. The transmitting member UE may also include a BSR in the scheduling request.

[0636] In step ST2706, the leader UE performs scheduling for PC5 communication between members using the QoS-related information and the BSR information included in the scheduling request received in step ST2705. In step ST2707, the leader UE notifies the transmitting member UE of scheduling information for PC5 communication between members.

[0637] When the transmitting member UE receives scheduling information for PC5 communication among members in step ST2707, in step ST2708, it uses the scheduling information to notify the receiving member UE of a PC5 communication request. For the processing from step ST2708 to step ST2711, the processing of steps ST2216 to ST2219 in FIG. 31 may be appropriately applied. Thereby, the transmission and reception of V2X service data are performed between the receiving member UE and the transmitting member UE.

[0638] In step ST2712, the transmitting member UE performs a QoS monitor. The transmitting member UE performs QoS-related parameter measurement, and in step ST2713, it notifies the reader UE of the measurement result. In step ST2714, the reader UE uses the QoS-related parameter measurement result notified from the transmitting member UE to perform scheduling for PC5 communication among members again. As the scheduling method for PC5 communication among members using the QoS-related parameter measurement result, the above-described method disclosed in Embodiment 2 may be applied.

[0639] In step ST2715, the reader UE notifies the transmitting member UE of the result information of the PC5 communication scheduling performed in step ST2714. The transmitting member UE uses the PC5 communication scheduling information to perform the transmission and reception of V2X service data with the receiving member UE in step ST2716. Here, the transmission and reception of V2X service data are disclosed, but the same applies to the transmission and reception of PC5-S signaling and PC5 RRC signaling.

[0640] In this way, by the transmitting member UE performing a QoS monitor and notifying the reader UE of the result of the QoS monitor, the reader UE can perform scheduling for PC5 communication among members using the QoS monitor result of PC5 communication among members. Therefore, even if the communication quality of PC5 communication among members c...

Claims

1. A communication terminal device in a communication system, The communication system includes a plurality of communication terminal devices including the communication terminal device, The communication terminal device performs PC5 communication, which is communication via a PC5 interface, with another communication terminal device among the plurality of communication terminal devices, The communication terminal device, transmits a V2X (Vehicle to X) policy provision request to a Policy Control Function (PCF) node via an Access and Mobility Management Function (AMF) node, receives V2X parameters transmitted in response to the V2X policy provision request from the PCF node via the AMF node, The V2X parameters include information regarding resources of the PC5 communication with an expiration date set, Communication terminal device.

2. The expiration date is set using a timer, The communication terminal device according to claim 1.

3. The information regarding the resources of the PC5 communication is set such that the resources are usable in a predetermined area, The communication terminal device according to claim 1.

4. The information regarding the resources of the PC5 communication includes information associating the resources with a V2X service, The communication terminal device according to claim 1.

5. A communication system including a plurality of communication terminal devices, A certain communication terminal device among the plurality of communication terminal devices performs PC5 communication, which is communication via a PC5 interface, with another communication terminal device among the plurality of communication terminal devices, The communication terminal device, Send the V2X (Vehicle to X) policy provision request to the Policy Control Function (PCF) node via the Access and Mobility Management Function (AMF) node. Receive the V2X parameters transmitted in response to the V2X policy provision request from the PCF node via the AMF node. The V2X parameters include information regarding the resources of the PC5 communication with an expiration date set. Communication system.

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