Communication terminal, base station, and communication system

Abstract

To provide a communication terminal, a base station, and a communication system that perform services using peer-to-peer communication such as V2X communication.SOLUTION: A communication system 200 comprises: a base station 203 that can communicate with an Evolved Packet Core (EPC) or a core network that a mobility management entity (MME) / serving gateway (S-GW) unit 204 configures and includes one or more eNBs 207; and a communication terminal 202 that can perform wireless communication with the base station. The base station supports a non-public network. The communication terminal performs a service using peer-to-peer communication and determines whether it can access the base station from information regarding in which non-public network different services using peer-to-peer communication are available.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

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

[0003] LTE uses OFDM (Orthogonal Frequency Division Multiplexing) for downlink and SC-FDMA (Single Carrier Frequency Division Multiple Access) for uplink as its access method. Unlike W-CDMA (Wideband Code Division Multiple Access), LTE does not include circuit switching and is only a packet communication method.

[0004] The decisions made by 3GPP regarding the frame configuration in the LTE system, as described in Non-Patent Document 1 (Chapter 5), will be explained using Figure 1. Figure 1 is an explanatory diagram showing the configuration of a radio frame used in an LTE communication system. In Figure 1, one radio frame is 10 ms. The radio frame is divided into 10 equally sized subframes. The subframe is divided into two equally sized slots. The first and sixth subframes of each radio frame include a downlink synchronization signal. The synchronization signals include a primary synchronization signal (P-SS) and a secondary synchronization signal (S-SS).

[0005] The decisions made by 3GPP regarding the channel configuration in the LTE system 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 in a CSG (Closed Subscriber Group) cell.

[0006] The Physical Broadcast Channel (PBCH) is a channel for downlink transmission from a base station (hereinafter simply referred to as a "base station") to a communication terminal (hereinafter simply referred to as a "communication terminal") such as a mobile terminal (hereinafter simply referred to as a "mobile terminal"). A BCH transport block is mapped to four subframes in a 40 ms interval. There is no explicit signaling of 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 communication terminal of the number of Orthogonal Frequency Division Multiplexing (OFDM) symbols used for PDCCHs. The PCFICH is transmitted every subframe.

[0008] The Physical Downlink Control Channel (PDCCH) is a channel for downlink transmission from a base station to a communication terminal. The PDCCH reports resource allocation information for a Downlink Shared Channel (DL-SCH), which is one of the transport channels described below, resource allocation information for a Paging Channel (PCH), which is also one of the transport channels described below, and Hybrid Automatic Repeat reQuest (HARQ) information for the DL-SCH. The PDCCH carries an uplink scheduling grant. The PDCCH carries Acknowledgement (Ack) / Negative Acknowledgement (Nack), which are response signals to uplink transmissions. 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. A Downlink Shared Channel (DL-SCH), which is a transport channel, and a PCH, which is also a transport channel, are mapped to the PDSCH.

[0010] A physical multicast channel (PMCH) is a channel for downlink transmission from a base station to communication terminals, and a 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 Ack / Nack, which are response signals to downlink transmissions. The PUCCH carries Channel State Information (CSI). The CSI consists of a Rank Indicator (RI), a Precoding Matrix Indicator (PMI), and a Channel Quality Indicator (CQI) report. The RI is information on the rank of the channel matrix in MIMO. The PMI is information on the precoding weight matrix used in MIMO. The CQI is quality information that indicates the quality of received data or the quality of the communication path. The PUCCH also carries a 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 channel for downlink transmission from a base station to a communication terminal. The PHICH carries Ack / Nack, which are response signals to uplink transmission. The Physical Random Access Channel (PRACH) is a channel for uplink transmission from a communication terminal to a base station. The PRACH carries a random access preamble.

[0014] Downlink reference signals (RS) are symbols known in LTE communication systems. The following five types of downlink reference signals are defined: Cell-specific Reference Signal (CRS), MBSFN Reference Signal, UE-specific reference signal Demodulation Reference Signal (DM-RS), Positioning Reference Signal (PRS), and Channel State Information Reference Signal (CSI-RS). Measurement of the physical layer of a communication terminal includes measurement of the reference signal received power (RSRP).

[0015] Similarly, the uplink reference signal is a symbol known in LTE communication systems. Two types of uplink reference signals are defined: a data demodulation reference signal (DM-RS) and a sounding reference signal (SRS).

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

[0017] Retransmission control using HARQ (Hybrid ARQ) is applied to the Downlink Shared Channel (DL-SCH). DL-SCH can be broadcast to the entire coverage of a base station (cell). DL-SCH supports dynamic or semi-static resource allocation. Semi-static resource allocation is also called persistent scheduling. DL-SCH supports discontinuous reception (DRX) in communication terminals to reduce power consumption of communication terminals. DL-SCH is mapped to the Physical Downlink Shared Channel (PDSCH).

[0018] The Paging Channel (PCH) supports DRX in communication terminals to enable low power consumption in communication terminals. The PCH is required to broadcast to the entire coverage of the base station (cell). The PCH is mapped to physical resources such as the Physical Downlink Shared Channel (PDSCH) that can be dynamically used for traffic.

[0019] The Multicast Channel (MCH) is used for broadcasting to the entire coverage of a base station (cell). The MCH supports SFN combining of MBMS (Multimedia Broadcast Multicast Service) services (MTCH and MCCH) in multi-cell transmission. The MCH supports semi-static resource allocation. The MCH is mapped to the PMCH.

[0020] Among the uplink transport channels, the Uplink Shared Channel (UL-SCH) is subject to retransmission control using HARQ (Hybrid ARQ). 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 is subject to collision risk. The RACH is mapped to the Physical Random Access Channel (PRACH).

[0022] We will explain HARQ. HARQ is a technology that improves the communication quality of a transmission channel by combining Automatic Repeat reQuest (ARQ) and Forward Error Correction. HARQ has the advantage that error correction works effectively through retransmission even on transmission channels where communication quality varies. In particular, by combining the reception results of the initial transmission and the retransmission when retransmitting, it is possible to achieve further quality improvement.

[0023] An example of a retransmission method will be explained below. If the receiving side is unable to decode the received data correctly, in other words, if a CRC (Cyclic Redundancy Check) error occurs (CRC=NG), the receiving side will send a "Nack" to the sending side. The sending side, having received the "Nack," will retransmit the data. If the receiving side is able to decode the received data correctly, in other words, if no CRC error occurs (CRC=OK), the receiving side will send an "Ack" to the sending side. The sending side, having received the "Ack," will send the next data.

[0024] The logical channels described in Non-Patent Document 1 (Chapter 6) will be explained below. 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) or the downlink shared channel (DL-SCH), which are transport channels.

[0025] The Paging Control Channel (PCCH) is a downlink channel for transmitting paging information and changes to 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] A Common Control Channel (CCCH) is a channel for transmission control information between a communication terminal and a base station. CCCH is used when a communication terminal does not have an RRC connection with the network. In the downlink direction, CCCH is mapped to a Downlink Shared Channel (DL-SCH), which is a transport channel. In the uplink direction, CCCH is mapped to an Uplink Shared Channel (UL-SCH), which is a transport channel.

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

[0028] A 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 an uplink shared channel (UL-SCH) in the uplink and to a downlink shared channel (DL-SCH) in the downlink.

[0029] A Dedicated Traffic Channel (DTCH) is a one-to-one communication channel for transmitting user information to an individual communication terminal. DTCH exists in both uplink and downlink. In uplink, DTCH is mapped to an uplink shared channel (UL-SCH) and in downlink, it is mapped to a downlink shared channel (DL-SCH).

[0030] The Multicast Traffic Channel (MTCH) is a downlink channel for transmitting traffic data from the network to communication terminals. The MTCH is a channel used only by communication terminals receiving MBMS. The MTCH is mapped to the Multicast Channel (MCH).

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

[0032] The location of a communication terminal is tracked in units of an area consisting of one or more cells. Location tracking is performed to track the location of the communication terminal even when it is in standby mode and to enable the communication terminal to be called, in other words, to allow the communication terminal to receive calls. The area used for tracking the location of this communication terminal is called a tracking area.

[0033] 3GPP is also working on the development of the Long Term Evolution Advanced (LTE-A) standard as Release 10 (see Non-Patent Documents 3 and 4). LTE-A is based on the LTE wireless communication system, and is configured by adding several new technologies to it.

[0034] In the LTE-A system, carrier aggregation (CA) is being considered, which aggregates two or more component carriers (CCs) (also called "aggregation") to support wider frequency bandwidths (transmission bandwidths) up to 100 MHz. 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] Depending on the UE's capabilities, a secondary cell (SCell) is configured to form a serving cell set 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, which includes one PCell and one or more SCells, is configured for one UE.

[0038] New technologies for LTE-A include wider bandwidth extension, coordinated multiple point transmission and reception (CoMP), etc. CoMP, which is being considered for LTE-A by 3GPP, is described in Non-Patent Document 1.

[0039] Furthermore, in order to handle future massive traffic volumes, 3GPP is considering using small eNBs (hereinafter sometimes referred to as "small-scale base station devices") that configure small cells. For example, technologies are being considered that aim to increase communication capacity by installing a large number of small eNBs and configuring a large number of small cells to improve frequency utilization efficiency. Specifically, there is dual connectivity (abbreviated as DC), in which a UE connects to two eNBs to communicate. DC is described in Non-Patent Document 1.

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

[0041] Mobile network traffic volume is on the rise, and communication speeds are also increasing. Once LTE and LTE-A are fully operational, communication speeds are expected to increase even further.

[0042] Furthermore, in response to the increasing sophistication of mobile communications, fifth-generation (hereinafter sometimes referred to as "5G") wireless access systems are being considered, with the goal of launching services after 2020. For example, in Europe, an organization called METIS has compiled requirements for 5G (see Non-Patent Document 5).

[0043] The requirements for a 5G wireless access system are that it will have 1,000 times the system capacity, 100 times the data transmission speed, one-tenth (1 / 10) the data processing delay, and 100 times the number of simultaneous connections of communication terminals compared to an LTE system, while also achieving further reductions in power consumption and lower equipment costs.

[0044] To meet these demands, 3GPP is currently working on 5G standards as Release 15 (see Non-Patent Documents 6 to 18). 5G wireless access technology is called "New Radio Access Technology" ("New Radio" is abbreviated as "NR").

[0045] The NR system is being developed based on the LTE system and LTE-A system, but the following changes and additions have been made to the LTE system and LTE-A system.

[0046] The NR access method uses OFDM in the downlink direction and OFDM and DFT-s-OFDM (DFT-spread-OFDM) in the uplink direction.

[0047] NR allows the use of higher frequencies than LTE in order to improve transmission speeds and reduce processing delays.

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

[0049] The NR frame structure supports various subcarrier spacings, i.e., various numerologies. In NR, regardless of the numerology, one subframe is 1 millisecond and one slot consists of 14 symbols. Furthermore, the number of slots included in one subframe is one in a numerology with a subcarrier spacing of 15 kHz, but increases in proportion to the subcarrier spacing in other numerologies (see Non-Patent Document 13 (TS38.211 V15.2.0)).

[0050] In NR, downlink synchronization signals are transmitted from base stations as synchronization signal bursts (hereinafter sometimes referred to as SS bursts) at predetermined intervals for a predetermined duration. SS bursts consist of synchronization signal blocks (hereinafter sometimes 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, changing the beam. SS blocks consist of P-SS, S-SS, and PBCH.

[0051] In NR, the influence of phase noise is reduced by adding a Phase Tracking Reference Signal (PTRS) as a downlink reference signal for NR. PTRS is also added to the uplink reference signal, just like in the downlink.

[0052] In NR, slot format indication (SFI) has been added to the information contained in the PDCCH in order to flexibly switch between DL and UL within a slot.

[0053] In addition, in NR, the base station pre-configures a portion of the carrier frequency band (hereinafter sometimes referred to as the Bandwidth Part (BWP)) for the UE, and the UE transmits and receives data to and from the base station using this BWP, thereby reducing power consumption in the UE.

[0054] 3GPP is considering the following DC forms: DC by LTE base stations and NR base stations connected to EPC, DC by NR base stations connected to a 5G core system, and DC by LTE base stations and NR base stations connected to a 5G core system (see Non-Patent Documents 12, 16, and 19).

[0055] 3GPP is also studying several new technologies. For example, it is studying support for V2X communication in both LTE and 5G core systems (Non-Patent Documents 1, 20, and 21). For example, it is studying connection to non-public networks (NPN) (see Non-Patent Documents 22 and 23). [Prior art documents] [Non-patent literature]

[0056] [Non-Patent Document 1] 3GPP TS 36.300 V15.4.0 [Non-patent document 2] 3GPP S1-083461 [Non-patent document 3] 3GPP TR 36.814 V9.2.0 [Non-patent document 4] 3GPP TR 36.912 V15.0.0 [Non-patent document 5] "Scenarios, requirements and KPIs for 5G mobile and wireless system", ICT-317669-METIS / D1.1

Non-licensed Document 6

Non-licensed Document 7

Non-licensed literature 9

Non-licensed literature 10

Non-licensed Document 11

Non-licensed Document 12

Non-licensed Document 13

Non-licensed Document 14

Non-licensed Document 15

Non-licensed Document 16

Non-licensed Document 17

Non-licensed Document 18

Non-licensed Document 19

Non-licensed Document 20

Non-licensed Document 21

[0057] Support for V2X communication in both LTE and 5G core systems is being considered (Non-Patent Documents 1, 20, and 21). Sidelink communication (also called PC5 communication) is supported in V2X communication. Enabling D2D communication using PC5 communication is being considered. When supporting PC5 communication, the issues are how to satisfy the QoS required for services using PC5 communication and how to reduce interference between services.

[0058] As mentioned above, 3GPP is considering the introduction of NPNs using 5G communication systems (hereinafter, sometimes referred to as 5G systems). For example, the introduction of NPNs using 5G indoors, such as in factories, is being considered (see Non-Patent Document 24 (3GPP TR23.734 V16.2.0)). There is also a demand for configuring an NPN indoors, such as in a factory, and supporting communication services between a base station and a terminal or device-to-device communication (Device to Device Communication (D2D Communication)) within the NPN (see Non-Patent Document 25 (3GPP S1-191338) and Non-Patent Document 26 (3GPP S1-191580)).

[0059] However, while methods for implementing V2X communication in conventional public networks have been disclosed, methods for implementing V2X communication in NPNs have not been disclosed. For example, access control is required in NPNs, but there is no disclosure at all about how to implement V2X communication in NPNs where access control is implemented. This creates a problem in that V2X communication and D2D communication cannot be implemented within NPNs.

[0060] This creates the problem of not being able to establish wireless communication technologies suitable for a wide range of industries, such as wireless communication within factories and V2X communication.

[0061] In view of the above-described problems, one object of the present disclosure is to provide a technology for implementing a service using terminal-to-terminal communication such as V2X communication. [Means for solving the problem]

[0062] According to the present disclosure, there is provided a communication system comprising a base station configured to be able to communicate with a core network, and a communication terminal configured to be able to communicate wirelessly with the base station, wherein the base station supports a non-public network, the communication terminal is configured to be able to implement services using terminal-to-terminal communication, and the communication terminal determines whether it can access the base station based on information regarding which non-public networks various services using the terminal-to-terminal communication are available on. Furthermore, according to the present disclosure, there is provided a communication terminal configured to be capable of wireless communication with a base station, wherein the base station supports a non-public network, the communication terminal is configured to be able to implement services using terminal-to-terminal communication, and the communication terminal determines whether or not it can access the base station based on information regarding which non-public networks various services using the terminal-to-terminal communication are available on. Furthermore, according to the present disclosure, there is provided a base station configured to be capable of wireless communication with a communication terminal, wherein the base station supports a non-public network, and the communication terminal is configured to be able to implement services using terminal-to-terminal communication, and the communication terminal determines whether or not it can access the base station based on identification information of the non-public network supported by the base station, the type of service provided by the communication terminal, and information regarding which non-public networks various services using the terminal-to-terminal communication are available on, and the base station transmits the identification information of the non-public network supported by the base station to the communication terminal. [Effects of the Invention]

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

[0064] The objects, features, aspects, and advantages of the present disclosure will become more apparent from the following detailed description and the accompanying drawings. [Brief explanation of the drawings]

[0065] [Figure 1] FIG. 1 is an explanatory diagram showing the configuration of a radio frame used in an LTE communication system. [Figure 2] 1 is a block diagram showing the overall configuration of an LTE communication system 200 being discussed in 3GPP. [Figure 3] FIG. 2 is a block diagram showing the overall configuration of a communication system 210 conforming to the NR standard under discussion in 3GPP. [Figure 4] This is a diagram illustrating the configuration of DC using eNB and gNB connected to EPC. [Figure 5] This is a diagram of the DC configuration using gNB connected to the NG core. [Figure 6] This is a diagram illustrating the configuration of DC using eNB and gNB connected to the NG core. [Figure 7] This is a diagram illustrating the configuration of DC using eNB and gNB connected to the NG core. [Figure 8] FIG. 3 is a block diagram showing the configuration of a mobile terminal 202 shown in FIG. [Figure 9] FIG. 3 is a block diagram showing the configuration of a base station 203 shown in FIG. [Figure 10] FIG. 2 is a block diagram illustrating the configuration of an MME. [Figure 11] A block diagram showing the configuration of 5GC. [Figure 12] 1 is a flowchart showing an outline of operations from cell search to standby operation performed by a communication terminal (UE) in an LTE communication system. [Figure 13] FIG. 1 is a diagram illustrating an example of a cell configuration in an NR system. [Figure 14] FIG. 10 is a diagram illustrating an example of a sequence for performing V2X Uu communication via a local NPN cell according to the first embodiment. [Figure 15] FIG. 10 is a diagram illustrating an example of a sequence for performing V2X Uu communication via a local NPN cell according to the first embodiment. [Figure 16] FIG. 10 is a diagram illustrating an example of a sequence for performing V2X PC5 communication via the own NPN cell, in accordance with the first modification of the first embodiment. [Figure 17] FIG. 10 is a diagram illustrating an example of a sequence for performing V2X PC5 communication via the own NPN cell, in accordance with the first modification of the first embodiment. [Figure 18] FIG. 10 is a diagram illustrating an example of a sequence for performing V2X PC5 communication via the own NPN cell, in accordance with the second modification of the first embodiment. [Figure 19] FIG. 10 is a diagram illustrating an example of a sequence for performing V2X PC5 communication via the own NPN cell, in accordance with the second modification of the first embodiment. [Figure 20] FIG. 11 is a diagram showing a first example of a sequence for performing PC5 communication outside the coverage of a cell to which the NPN belongs, in accordance with the third modification of the first embodiment. [Figure 21] FIG. 11 is a diagram showing a second example of a sequence for performing PC5 communication outside the coverage of the cell to which the own NPN belongs, in accordance with the third modification of the first embodiment. [Figure 22]FIG. 13 is a diagram illustrating an example of a sequence for performing PC5 communication via a cell that does not belong to the own NPN, in accordance with the fourth modification of the first embodiment. [Figure 23] FIG. 13 is a diagram illustrating an example of a sequence for performing PC5 communication via a cell that does not belong to the own NPN, in accordance with the fourth modification of the first embodiment. [Figure 24] FIG. 13 is a diagram showing a first example of a sequence for performing PC5 communication via a cell that does not belong to the own NPN, in accordance with the fifth modification of the first embodiment. [Figure 25] FIG. 13 is a diagram showing a first example of a sequence for performing PC5 communication via a cell that does not belong to the own NPN, in accordance with the fifth modification of the first embodiment. [Figure 26] FIG. 13 is a diagram showing a second example of a sequence for performing PC5 communication via a cell that does not belong to the own NPN, in accordance with the fifth modification of the first embodiment. [Figure 27] FIG. 13 is a diagram showing a second example of a sequence for performing PC5 communication via a cell that does not belong to the own NPN, in accordance with the fifth modification of the first embodiment. [Figure 28] FIG. 11 is a diagram illustrating an example of a sequence for performing QoS monitoring of PC5 communication in accordance with the second embodiment. [Figure 29] FIG. 11 is a diagram illustrating an example of a sequence for performing QoS monitoring of PC5 communication in accordance with the second embodiment. [Figure 30] FIG. 10 is a diagram illustrating an example of a sequence for performing QoS monitoring of PC5 communication in accordance with the first modification of the second embodiment. [Figure 31] FIG. 10 is a diagram illustrating an example of a sequence for performing QoS monitoring of PC5 communication in accordance with the first modification of the second embodiment. [Figure 32] FIG. 10 is a diagram illustrating an example of a sequence for performing QoS monitoring of PC5 communication in accordance with the first modification of the second embodiment. [Figure 33] FIG. 10 is a diagram showing a first example of a sequence for performing QoS monitoring of PC5 communication in accordance with the third modification of the second embodiment. [Figure 34]FIG. 10 is a diagram showing a first example of a sequence for performing QoS monitoring of PC5 communication in accordance with the third modification of the second embodiment. [Figure 35] FIG. 10 is a diagram illustrating a second example of a sequence for performing QoS monitoring of PC5 communication in accordance with the third modification of the second embodiment. [Figure 36] FIG. 10 is a diagram illustrating a second example of a sequence for performing QoS monitoring of PC5 communication in accordance with the third modification of the second embodiment. [Figure 37] FIG. 10 is a diagram illustrating a third example of a sequence for performing QoS monitoring of PC5 communication in accordance with the third modification of the second embodiment. [Figure 38] FIG. 10 is a diagram illustrating an example of a sequence for performing QoS monitoring of PC5 communication in accordance with the fourth modification of the second embodiment. [Figure 39] FIG. 11 is a diagram illustrating a first example of a sequence for implementing network slicing in a V2X service using PC5 communication, according to the third embodiment. [Figure 40] FIG. 11 is a diagram illustrating a second example of a sequence for implementing network slicing in a V2X service using PC5 communication, in accordance with the third embodiment. [Figure 41] FIG. 11 is a diagram illustrating a second example of a sequence for implementing network slicing in a V2X service using PC5 communication, in accordance with the third embodiment. [Figure 42] FIG. 11 is a diagram illustrating a third example of a sequence for implementing network slicing in a V2X service using PC5 communication, in accordance with the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0066] Embodiment 1 Fig. 2 is a block diagram showing the overall configuration of an LTE communication system 200 being discussed in 3GPP. Fig. 2 will now be described. The radio access network is called E-UTRAN (Evolved Universal Terrestrial Radio Access Network) 201. A mobile terminal device (hereinafter referred to as "mobile terminal (User Equipment: UE)") 202, which is a communication terminal device, is capable of wireless communication with a base station device (hereinafter referred to as "base station (E-UTRAN NodeB: eNB)") 203, and transmits and receives signals via wireless communication.

[0067] Here, the term "communication terminal device" includes not only mobile terminal devices such as mobile cell phone terminal devices, but also stationary devices such as sensors. In the following description, the term "communication terminal device" may be simply referred to as a "communication terminal."

[0068] If control protocols for mobile terminals 202, such as RRC (Radio Resource Control), and user planes (hereinafter sometimes referred to as U-Planes), such as PDCP (Packet Data Convergence Protocol), RLC (Radio Link Control), MAC (Medium Access Control), and PHY (Physical layer), terminate at base stations 203, 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 broadcasting, paging, RRC connection management, etc. The states of the base station 203 and the mobile terminal 202 in RRC include RRC_IDLE and RRC_CONNECTED.

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

[0071] The base station 203 is configured by one or more eNBs 207. A system configured by the core network EPC (Evolved Packet Core) and the radio access network E-UTRAN 201 is called an EPS (Evolved Packet System). The core network EPC and the radio access network E-UTRAN 201 are sometimes collectively referred to as a "network."

[0072] The eNB 207 is connected to a Mobility Management Entity (MME), or a Serving Gateway (S-GW), or an MME / S-GW unit (hereinafter sometimes referred to as an "MME unit") 204 including an MME and an S-GW via an 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 to each other via an X2 interface, and control information is communicated between the eNBs 207.

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

[0074] Base station 203 may configure one cell or multiple cells. Each cell has a predetermined range as coverage, which is the range within which communication with mobile terminal 202 is possible, and performs wireless communication with mobile terminal 202 within the coverage. When one base station 203 configures multiple cells, each cell is configured to be able to communicate with mobile terminal 202.

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

[0076] If control protocols for UE202, such as RRC (Radio Resource Control), and user planes (hereinafter sometimes referred to as U-Planes), such as SDAP (Service Data Adaptation Protocol), PDCP (Packet Data Convergence Protocol), RLC (Radio Link Control), MAC (Medium Access Control), and PHY (Physical layer), terminate at an NR base station 213, the NG-RAN is composed of one or more 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. The states of the NR base station 213 and the UE 202 in the RRC include RRC_IDLE, RRC_CONNECTED, and RRC_INACTIVE.

[0078] RRC_IDLE and RRC_CONNECTED are the same as those in the LTE system. RRC_INACTIVE maintains the connection between the 5G core and the NR base station 213, and performs system information (SI), paging, cell reselection, mobility, and the like.

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

[0080] The NR base station 213 may configure one or more cells, similar to the base station 203. When one NR base station 213 configures multiple cells, each cell is configured to be able to communicate with the UE 202.

[0081] The gNB 217 may be divided into a central unit (hereinafter, sometimes referred to as a CU) 218 ​​and distributed units (hereinafter, sometimes referred to as DUs) 219. One CU 218 is configured in the gNB 217. One or more DUs 219 are configured in the gNB 217. The CU 218 is connected to the DU 219 via an F1 interface, and control information and / or user data is 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 PCF may be included in the 5GC unit 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 an Access Network (AN) in non-3GPP access between the UE and the N3IWF.

[0084] Fig. 4 is a diagram showing a DC configuration by eNBs and gNBs connected to EPC. In Fig. 4, solid lines indicate U-Plane connections, and dashed lines indicate C-Plane connections. In Fig. 4, eNB223-1 serves as the master base station, and gNB224-2 serves as the secondary base station (this DC configuration may be referred to as EN-DC). Fig. 4 shows an example in which U-Plane connection between MME unit 204 and gNB224-2 is made via eNB223-1, but it may also be made directly between MME unit 204 and gNB224-2.

[0085] Figure 5 is a diagram showing the configuration of DC by a gNB connected to an NG core. In Figure 5, solid lines indicate U-Plane connections, and dashed lines indicate C-Plane connections. In Figure 5, gNB 224-1 is the master base station, and gNB 224-2 is the secondary base station (this DC configuration may be referred to as NR-DC). Figure 5 shows an example in which U-Plane connection between 5GC unit 214 and gNB 224-2 is made via gNB 224-1, but it may also be made directly between 5GC unit 214 and gNB 224-2.

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

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

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

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

[0090] 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, and 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 transmission data buffer unit 404 is passed to encoder unit 405, where it undergoes encoding processing such as error correction. Some data may be output directly from transmission data buffer unit 404 to modulation unit 406 without undergoing encoding processing. The encoded data is modulated by modulation unit 406. MIMO precoding may be performed by modulation unit 406. The modulated data is converted into a baseband signal, and then output to frequency conversion unit 407, where it is converted into a radio transmission frequency. Thereafter, a transmission signal is transmitted to one or more mobile terminals 202 from antennas 408-1 to 408-4. Although FIG. 9 illustrates an example in which the number of antennas is four, the number of antennas is not limited to four.

[0092] The reception process of the base station 203 is performed as follows: A radio signal from one or more mobile terminals 202 is received by an antenna 408. The received signal is converted from a radio reception frequency to a baseband signal by a frequency conversion unit 407, and demodulated by a demodulation unit 409. The demodulated data is passed to a decoder unit 410, where decoding processes such as error correction are performed. Of the decoded data, 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 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 a control unit 411. Therefore, although the control unit 411 is omitted in FIG. 9, it is connected to each unit 401 to 410. In FIG. 9, the number of antennas used for transmission by the base station 203 and the number of antennas used for reception may be the same or different.

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

[0094] 10 is a block diagram showing the configuration of an MME. FIG. 10 shows the configuration of an MME 204a included in the MME unit 204 shown in FIG. 2 described above. A PDN GW communication unit 501 transmits and receives data between the MME 204a and a PDN GW. A base station communication unit 502 transmits and receives data via the S1 interface between the MME 204a and a base station 203. If 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 a user plane communication unit 503, and transmitted to one or more base stations 203. If 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 plane communication unit 503, and transmitted to the PDN GW.

[0095] If 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. If 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 a 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 sometimes referred to as the C-Plane). The NAS security unit 505-1 performs security for 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 idle state (also referred to as the LTE-IDLE state or simply idle), generation and control of paging signals in the idle state, addition, deletion, update, and search of tracking areas for one or more mobile terminals 202 under its control, tracking area list management, etc.

[0097] The MME 204a distributes paging signals to one or more base stations 203. The MME 204a also performs mobility control in an idle state. The MME 204a manages a tracking area list when the mobile terminal is in an idle state and an active state. The MME 204a initiates a paging protocol by transmitting a paging message to a cell belonging to a tracking area in which the UE is registered. The idle state mobility management unit 505-3 may manage the CSG, CSG ID, and whitelist of the eNB 207 connected to the MME 204a.

[0098] FIG. 11 is a block diagram showing the configuration of 5GC. FIG. 11 shows the configuration of the 5GC unit 214 shown in FIG. 3 described above. FIG. 11 shows a case where the 5GC unit 214 shown in FIG. 5 includes an AMF configuration, an SMF configuration, and a UPF configuration. 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 plane communication unit 523, and transmitted to one or more base stations 203 and / or base stations 213. If the data received from base station 203 and / or base station 213 is user data, the user data is passed from base station communication unit 522 to data network communication unit 521 via user plane communication unit 523 and transmitted to the data network.

[0099] If 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. If the data received from the base station 203 and / or 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 sometimes referred to as the C-Plane). The NAS security unit 525-1 performs security for NAS (Non-Access Stratum) messages, etc. The PDU session control unit 525-2 performs management of PDU sessions between the mobile terminal 202 and the 5GC unit 214, etc. The idle state mobility management unit 525-3 performs mobility management in the idle state (also referred to as the RRC_IDLE state or simply idle), generation and control of paging signals in the idle state, addition, deletion, update, and search of tracking areas for one or more mobile terminals 202 under its control, tracking area list management, etc.

[0101] The 5GC unit 214 distributes paging signals to one or more base stations 203 and / or base station 213. The 5GC unit 214 also performs mobility control in an idle state. The 5GC unit 214 manages a tracking area list when the mobile terminal is in an idle state, an inactive state, or an active state. The 5GC unit 214 initiates a paging protocol by transmitting a paging message to a cell belonging to a 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 outline of the process from cell search to standby operation performed by a communication terminal (UE) in an LTE communication system. When the communication terminal starts a cell search, in step ST601, it synchronizes slot timing and frame timing using a primary synchronization signal (P-SS) and a secondary synchronization signal (S-SS) transmitted from a surrounding base station.

[0103] P-SS and S-SS are collectively called the Synchronization Signal (SS). The Synchronization Signal (SS) is assigned a synchronization code that corresponds one-to-one to the PCI assigned to each cell. 504 different PCIs are being considered. These 504 different PCIs are used to achieve synchronization and to detect (identify) the PCI of the synchronized cell.

[0104] Next, in step ST602, for the synchronized cell, a cell-specific reference signal (CRS), which is a reference signal (RS) transmitted from the base station for each cell, is detected and the RS received power (Reference Signal Received Power: RSRP) is measured. The RS uses a code that has a one-to-one correspondence with the PCI. By correlating with this code, it is possible to separate the cell from other cells. By deriving the code for the RS of the cell from the PCI identified in step ST601, it is possible to detect the RS and measure the RS received power.

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

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

[0107] Next, in step ST605, the DL-SCH of the cell is received based on the cell configuration information in the MIB, and SIB (System Information Block) 1 is obtained from the broadcast information BCCH. SIB 1 includes information on access to the cell, information on cell selection, and scheduling information for other SIBs (SIBk; k is an integer greater than or equal to 2). SIB 1 also includes a tracking area code (TAC).

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

[0109] If the comparison in step ST606 shows that the TAC received in step ST605 is the same as the TAC included in the tracking area list, the communication terminal enters standby mode in the cell. If the comparison shows that the TAC received in step ST605 is not included in the tracking area list, the communication terminal requests a core network (EPC) including an MME, etc., to change the tracking area in order to perform a Tracking Area Update (TAU) through the cell.

[0110] In the example shown in Fig. 12, an example of operations from cell search to standby in the LTE system is shown, but in the NR system, in addition to the best cell, the best beam may be selected in step ST603. Also, in the NR system, beam information, for example, a beam identifier, may be acquired in step ST604. Also, in the NR system, scheduling information of remaining minimum SI (RMSI) may be acquired in step ST604. In the NR system, RMSI may be received in step ST605.

[0111] An apparatus constituting a core network (hereinafter sometimes referred to as a "core network side apparatus") updates the tracking area list based on the identification number (e.g., UE-ID) of the communication terminal sent from the communication terminal together with a TAU request signal. The core network side apparatus 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 standby operation in the cell.

[0112] The widespread use of smartphones and tablet devices has led to an explosive increase in cellular wireless communication traffic, raising concerns about a shortage of wireless resources worldwide. In response to this, efforts are being made to develop small cells and promote spatial separation in order to improve frequency utilization efficiency.

[0113] In a conventional cell configuration, a cell configured by an eNB has a relatively wide coverage area. Conventionally, a cell is configured so that a certain area is covered by the relatively wide coverage areas of multiple cells configured by multiple eNBs.

[0114] In the case of small cell configuration, a cell configured by an eNB has a narrower coverage area than a cell configured by a conventional eNB. Therefore, as in the past, a larger number of small cell configuration eNBs are required to cover a certain area compared to conventional eNBs.

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

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

[0117] The small eNB may be, for example, a low-power node, a local area node, a hotspot, etc. Also, the small eNB may be a pico eNB constituting a pico cell, a femto eNB constituting a femto cell, a HeNB, a remote radio head (RRH), a remote radio unit (RRU), a remote radio equipment (RRE), or a relay node (RN). Also, the small eNB may be a "local area base station" or a "home base station" as described in Non-Patent Document 7.

[0118] FIG. 13 shows an example of a cell configuration in NR. In an NR cell, narrow beams are formed and transmitted while changing direction. In the example shown in FIG. 13, at a certain time, base station 750 transmits and receives signals to and from a mobile terminal using beam 751-1. At another time, base station 750 transmits and receives signals to and from a mobile terminal using beam 751-2. In a similar manner, base station 750 transmits and receives signals to and from a mobile terminal using one or more of beams 751-3 to 751-8. In this way, base station 750 configures a wide-area cell.

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

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

[0121] The physical channels used for SL (see Non-Patent Document 1) will be described below. A physical sidelink broadcast channel (PSBCH) carries information related to the system and synchronization, and is transmitted from a 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 and V2X sidelink communications.

[0124] The physical sidelink shared channel (PSSCH) carries data from the UE for sidelink and V2X sidelink communications.

[0125] The transport channel used for SL (see Non-Patent Document 1) will be described below. The sidelink broadcast channel (SL-BCH) has a predetermined transport format and is mapped to the PSBCH, which is a physical channel.

[0126] The Sidelink Discovery Channel (SL-DCH) has periodic broadcast transmissions of a fixed size and a predetermined format. The SL-DCH supports both UE autonomous resource selection and eNB-scheduled resource allocation. UE autonomous resource selection involves a collision risk, whereas when the UE is allocated dedicated resources by the eNB, there is no collision. The SL-DCH supports HARQ combining but not HARQ feedback. The SL-DCH is mapped to the PSDCH, a physical channel.

[0127] The Sidelink Shared Channel (SL-SCH) supports broadcast transmission. It supports both UE autonomous resource selection and eNB-scheduled resource allocation. While UE autonomous resource selection involves a collision risk, there is no collision when the UE is allocated dedicated resources by the eNB. The SL-SCH also supports HARQ combining but not HARQ feedback. The SL-SCH also supports dynamic link adaptation by varying transmit power, modulation, and coding. The SL-SCH is mapped to the PSSCH, a physical channel.

[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 broadcasting sidelink system information from one UE to other UEs. The SBCCH is mapped to the SL-BCH, which is a transport channel.

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

[0130] 3GPP is considering supporting V2X communication in NR as well. The study of V2X communication in NR is being carried out based on the LTE system and LTE-A system, but the following changes and additions have been made from the LTE system and LTE-A system.

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

[0132] For unicast and groupcast communications, 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 implemented to establish a link for implementing SL, i.e., PC5 communication. This link is implemented in the V2X layer and is also called a Layer 2 link.

[0134] Furthermore, support for RRC signaling in SL communication is being considered (see Non-Patent Document 21 (TS23.287)). RRC signaling in SL communication is also referred to as PC5 RRC signaling. For example, it has been proposed to notify UE capabilities between UEs performing PC5 communication, and to notify AS layer settings for V2X communication using PC5 communication.

[0135] 3GPP has proposed support for SL communication (hereinafter sometimes referred to as PC5 communication) within an NPN. For example, it has been proposed to build an NPN in a factory environment and perform terminal-to-terminal communication within the NPN using PC5 communication (see Non-Patent Document 25 (3GPP S1-191338)). It has also been proposed to operate AGVs (Automated Guided Vehicles) in cooperation within a factory NPN 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 demand for PC5 communication within an NPN and / or Uu communication between a base station and a terminal.

[0136] There are two types of NPNs: S-NPN (standalone NPN) and NS-NPN (non-standalone NPN) that use CAG (Closed Access Group). S-NPN is an NPN configured without the support of a public network and is identified by a PLMN ID and NID (Network ID). NS-NPN is an NPN configured with the support of a public network and uses a CAG to prevent unauthorized UEs from connecting. A CAG is identified by a CAG ID within the scope of a single PLMN ID. In this specification, unless otherwise specified, NPN refers to both S-NPN and NS-NPN without distinction.

[0137] In conventional technologies, it is not assumed that V2X services will be provided within an NPN, and a UE does not know which NPN supports services that use D2D communication, V2V communication, or V2X communication (these services may be hereinafter referred to as V2X services). For this reason, for example, the UE cannot recognize an NPN that can implement the desired V2X service, which causes a problem in that the V2X service cannot be provided.

[0138] Conversely, if any NPN were allowed to implement any V2X service, any UE would be able to provide the V2X service within the NPN, which would pose a problem in that it would be impossible to restrict the UEs that can access the NPN for V2X services.

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

[0140] The UE is capable of performing any V2X service in the accessible NPN. The UE is capable of using D2D communication, V2V communication, or V2X communication for any V2X service in the accessible NPN. The UE is capable of using Uu communication or PC5 communication for any V2X service in the accessible NPN. The UE is not permitted or denied access when performing Uu communication or PC5 communication for any V2X service in the accessible NPN.

[0141] In this way, the UE can identify the NPN that can implement the V2X service.

[0142] However, the above-mentioned method creates a further problem. For example, when a UE implements multiple V2X services, all V2X services can be implemented within the same NPN. This creates a problem in that, for example, even if multiple NPNs are built in a factory, each NPN cannot support different V2X services.

[0143] A method for solving such problems is disclosed.

[0144] Associate V2X services with NPNs. It is preferable to set an NPN that can use the V2X service. It is also possible to set one NPN that can use one or more V2X services. It is also possible to set one or more NPNs that can use one V2X service. It is also possible to use information that associates information about V2X services with information about NPNs that can use the V2X service.

[0145] An identifier for identifying a V2X service may be used as the V2X service information. For example, a provider service identifier (PSID) or an intelligent transport systems application identifier (ITS-AID) may be used. As NPN information, an S-NPN identifier may be used in the case of an S-NPN, and an NS-NPN identifier may be used in the case of an NS-NPN. A PLMN ID and / or an NID may be used as the S-NPN identifier, and a CAG identifier may be used as the NS-NPN identifier. A CAG-ID and / or a CAG allowed list, which is a list of CAG-IDs, may be used as the CAG identifier.

[0146] Information about NPNs that can use the V2X service may be stored in a CN (Core Network).In the CN, information about NPNs that can use the V2X service may be stored in a UDM (Unified Data Management) or UDR (Unified Data Repository) that manages and records UE registration information, etc. Information about NPNs that can use the V2X service may be stored in a PCF (Policy Control Function) that controls policies, an AMF (Access and Mobility Management function) that manages access and mobility, or an SMF (Session Management function) that manages sessions.

[0147] A node having information about NPNs that can use the V2X service may notify the UE of the information. For example, if a PCF has information about NPNs that can use the V2X service, the PCF may notify the UE of the information. The PCF may notify the UE of the information via an AMF. A node having information about NPNs that can use the V2X service may notify a RAN node (e.g., a gNB) of the information. A node having information about NPNs that can use the V2X service may notify a RAN node of the information via an AMF.

[0148] The AMF may obtain information about NPNs that can use the V2X service from the UDM, UDR, or PCF. The AMF may notify the UDM, UDR, or PCF of a message requesting information about NPNs that can use the V2X service. The UDM, UDR, or PCF that receives the request may notify the AMF of the information. The SMF may obtain the information from the AMF. In this way, each node can obtain information about NPNs that can use the V2X service and use the information as needed.

[0149] Information about NPNs that can use the V2X service may be stored in an OAM (Operations, Administration, and Maintenance) that has a maintenance management function. The AMF may obtain information about NPNs that can use the V2X service from the OAM. In this way, the OAM can provide information about NPNs that can use the V2X service to the network node.

[0150] Information about NPNs that can use the V2X service may be stored in the UE. Information about NPNs that can use the V2X service may be stored in a (U)SIM ((Universal) Subscriber Identity Module) or a UICC (Universal Integrated Circuit Card). In this way, the UE can use information about NPNs that can use the V2X service as needed.

[0151] V2X service information and information on NPNs that can use the V2X service may be included in V2X service-related information (hereinafter, sometimes referred to as V2X communication-related information). The V2X service-related information may include a V2X policy or V2X parameters, the V2X service information, and information on NPNs that can use the V2X service. Furthermore, the V2X policy or V2X parameters may include the V2X service information and V2X parameters of the NPNs that can use the V2X service. The V2X service-related information may be a V2X policy or V2X parameters that include the V2X service information and V2X parameters of the NPNs that can use the V2X service.

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

[0153] The PCF may notify the UE of V2X service information and information on NPNs that can use the V2X service. For example, the PCF may include the V2X service information and information on NPNs that can use the V2X service in V2X service-related information and notify the UE of the information. The PCF may notify the UE via an AMF or a RAN node. In this way, the UE can recognize the V2X service information and information on NPNs that can use the V2X service.

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

[0155] The PCF may notify the RAN node via the AMF. The RAN node may also obtain V2X service information and information on NPNs that can use the V2X service from the OAM. In this way, the RAN node can recognize V2X service information and information on NPNs that can use the V2X service. The RAN node can recognize V2X services that can be performed in NPNs supported by the cell. The RAN node can schedule Uu communication for UEs in V2X services that can be performed in NPNs supported by the cell using the V2X service-related information obtained from the PCF.

[0156] The UE may determine accessible cells using V2X service information and information on NPNs available for the V2X service. To determine accessible cells, information on NPNs broadcast by a cell may be used. For example, the UE derives an NPN available for the V2X service to be implemented using the V2X service information and information on NPNs available for the V2X service, and compares the derived NPN with information on accessible NPNs broadcast by a cell. If the derived NPN is included in information on accessible NPNs broadcast by a cell, the UE determines that the cell is accessible and accesses the cell. If the derived NPN is not included in information on accessible NPNs broadcast by a cell, the UE determines that the cell is inaccessible and does not access the cell. If the cell is inaccessible, the UE may reselect an accessible cell.

[0157] The information about the NPN may include information that allows a person to identify the NW. For example, information that allows a person to identify the name of the PLMN to which the person subscribes may be used. When the UE receives information that allows the NW to be identified, the information may be displayed to a person. For example, the information may be displayed on a display of a UE installed in a vehicle. A person may also determine whether or not to allow NPN access. As described above, by providing information that allows a person to identify the NW and making the information recognizable by a person, a person can determine whether or not to allow NPN access. This makes it possible to determine whether or not to allow NPN access based on a person's preferences.

[0158] The AMF may notify the UE of not only information about the V2X service and the NPNs that can use it, but also information about neighboring RAN nodes that support the V2X service and the NPNs that can use it. The RAN node may be a gNB or a cell. The AMF may notify the information about the neighboring RAN nodes via the RAN node on which the UE is camped. The RAN node may notify the UE of information about neighboring RAN nodes that support the V2X service and the NPNs that can use it.

[0159] The AMF may notify the UE of the V2X services supported by neighboring RAN nodes of the RAN node on which the UE is camped and information on NPNs that can use the V2X services. The AMF may notify the information on the neighboring RAN nodes via the RAN node on which the UE is camped. The RAN node may notify the UE of the V2X services supported by neighboring RAN nodes and information on NPNs that can use the V2X services.

[0160] A RAN node may notify neighboring RAN nodes of information about NPNs supported by the node itself. The information about NPNs supported by a RAN node may be information about NPNs supported for each cell. Information about NPNs supported for each carrier frequency may be notified for each cell. Alternatively, information about NPNs supported for each PLMN may be notified. The information may be notified using the base station-to-base station interface Xn.

[0161] A RAN node may notify neighboring RAN nodes of information about V2X services it supports. The information about V2X services supported by a RAN node may be information about V2X services supported for each cell. Information about V2X services supported for each carrier frequency may be notified instead of for each cell. Alternatively, information about V2X services supported for each PLMN may be notified. The information may be notified using the base station-to-base station interface Xn.

[0162] A RAN node may notify neighboring RAN nodes of information about V2X services it supports and information about NPNs that can use the V2X services. The information may be notified for each cell, each carrier frequency, or each PLMN. The information may be notified using the base station-to-base station interface Xn.

[0163] By having the RAN node notify neighboring RAN nodes of this information, it becomes unnecessary for the AMF to notify the UE. By eliminating the need for processing in the core network (CN), it becomes possible to reduce the processing load on the CN and the amount of signaling between the CN and RAN.

[0164] In this way, the UE can select and access a RAN node that can use the V2X service. Also, the UE will determine that it cannot access a RAN node that does not support an NPN that can use the V2X service, and will not access that node. It is possible to make the V2X service unavailable in NPNs other than those that can use the V2X service. In other words, it is possible to limit the V2X service available in an NPN.

[0165] 14 and 15 are diagrams showing an example of a sequence for performing V2X Uu communication via the own NPN cell according to the first embodiment. FIG. 14 and FIG. 15 are connected at the position of boundary line BL1415. FIG. 14 and FIG. 15 show the operations of the UE, RAN node, AMF, SMF, UPF, and PCF. In step ST1401, the RAN node broadcasts NPN-related information to the UE. The UE receives the NPN-related information, and in step ST1403, uses the received NPN-related information to determine whether or not it is possible to access the RAN node.

[0166] For example, if the identifier of the NPN broadcast from the RAN node is included in the identifier of the NPN that the UE has, the UE determines that it can access the RAN node. If not included, the UE determines that it cannot access the RAN node. If the UE determines that it cannot access the RAN node, it may perform a process of reselecting another RAN node. If the UE determines that it can access the RAN node, in Step ST1406, the UE notifies the RAN node of the NPN-related information and V2X capability. In Step ST1407, the RAN node notifies the AMF of the NPN-related information and 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 notify the NPN-related information and the V2X capability by including them in a message for a registration process. For example, the UE may notify the NPN-related information and the V2X capability by including them in a message for a service request process.

[0168] For example, RRC signaling may be used between the UE and the RAN node to notify the NPN-related information and the V2X capability. When RRC signaling is used, the NPN-related information and the V2X capability may be notified, for example, during an RRC connection establishment procedure.

[0169] For example, NG signaling may be used between the RAN node and the AMF to signal the NPN-related information and V2X capabilities. The NG signaling may be N2 signaling.

[0170] In step ST1411, the AMF performs NPN accessibility 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 to which the UE is registered, the AMF determines that access is possible. If not, the AMF determines that access is not possible. If the AMF determines that access is not possible, it may notify the UE of an access denial (reject) message. The access denial message may include reason information. The reason information may be information indicating that access is denied because the NPN is different.

[0171] If the AMF determines that the UE is accessible, it recognizes that the V2X service can be provided using the V2X capability received from the UE. The UE may notify V2X service provision request information along with the V2X capability. The AMF can then recognize that the UE is clearly requesting the provision of V2X service.

[0172] In Step ST1413, the AMF notifies the PCF of the V2X capability received from the UE. For this notification, for example, the AMF may use the Npcf interface or a UE Policy Control Create Request message.

[0173] The UE may notify the PCF of a V2X policy provision request. The UE may notify the PCF by including the request in a UE Policy Container to be notified. The UE may notify the PCF of the request via the AMF. The notification from the UE to the AMF may be made, for example, using NAS signaling. For example, a UE Policy Provision Request message may be used. The notification from the AMF to the PCF may be made, for example, using the Npcf interface or a UE Policy Control Update message.

[0174] In Step ST1414, the PCF that has received the information from the UE performs V2X service authentication using the registration data of the UE. The PCF also decides to provide a V2X policy to the UE. The PCF also decides to provide information on the V2X service and the NPNs that can use the V2X service to the UE. The V2X policy may include V2X parameters. The V2X policy may include information on the V2X service and the NPNs that can use the V2X service.

[0175] In Step ST1415, the PCF notifies the AMF of V2X communication related information. The V2X communication related information includes information about the V2X service and the NPNs that can use it. The V2X communication related information may include a V2X policy. The V2X policy may include information about the V2X service and the NPNs that can use it. The information about the V2X service and the NPNs that can use it may be associated with V2X parameters. The V2X parameters include, for example, QoS parameters for each V2X service. The PCF may notify the AMF of the V2X communication related information by using a UE policy provision procedure. For this notification, for example, the Namf interface 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 notify NPN related information. The NPN related information may include updated information on the list of NPNs that the UE is permitted to access. N2 signaling may be used for this notification. In this way, the RAN node can acquire the V2X related information for the UE. By the RAN node acquiring the V2X related information for the UE, the RAN node can perform scheduling for the V2X service 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. RRC signaling individual to the UE may be used for the notification from the RAN node to the UE. In this way, the UE also becomes able to acquire the V2X communication related information. Furthermore, the UE becomes able to acquire the NPN related information.

[0178] Although it has been shown that NPN-related information and V2X communication-related information are notified using the same signaling, they may be notified using different signaling. By using separate signaling, for example, AMF can notify NPN-related information without waiting for V2X policy provision processing between AMF and PCF. Early notification of NPN-related information makes it possible, for example, to apply NPN update information early.

[0179] In Step ST1420, a V2X service using Uu communication is generated in the UE. If the UE is not camped on a cell in an NPN that can use the V2X service, in Step ST1422, the UE selects or reselects a cell in the NPN that can use the V2X service. The UE may use the information on the V2X service and the NPN that can use the V2X service, acquired in Step ST1417, for the selection / reselection. In this way, the UE can implement the desired V2X service in the NPN to which the UE is permitted to access.

[0180] In Step ST1425, the UE notifies the selected / reselected cell of the NPN-related information and the V2X capability. In Step ST1426, the RAN node constituting the cell notifies the AMF of the NPN-related information and the V2X capability acquired from the UE. In this way, the AMF can acquire the NPN-related information and the V2X capability from the UE.

[0181] In Step ST1431, the AMF performs NPN accessibility 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 the NW, in Step ST1449, the AMF 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 capability notified from the UE to the AMF via the RAN node may include information that the UE has already been provided with a V2X policy. Alternatively, if the UE has already been provided with a V2X policy, the UE may not notify the AMF of a V2X policy provision request. When the AMF is notified of this information, it may not need to request V2X communication-related information from the PCF. This makes it possible to reduce the V2X communication-related information provision process.

[0183] In the examples of Figures 14 and 15, it is shown that the access authentication and policy provision processes for V2X communication are performed in advance via a RAN node that the UE can access. However, this process may be performed after the V2X service is generated. This eliminates the need for the UE and CN to maintain unnecessary registration or connection states. This prevents the UE and CN from using resources required in those states until the V2X service is generated. This makes it possible to improve resource usage efficiency.

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

[0185] The method disclosed in the first embodiment makes it possible to provide V2X services using Uu communication in an NPN. A UE can access an NPN that can use the V2X service, but cannot access an NPN that cannot use the V2X service. It is possible to limit the V2X services available in an NPN. It is also possible to perform Uu communication for V2X services that can be supported for each NPN. It is also possible to prevent Uu communication for V2X services that cannot be supported for each NPN.

[0186] Variation 1 of Embodiment 1 In this first modification, a method of providing a V2X service using terminal-to-terminal communication such as D2D communication or V2V communication (hereinafter, sometimes referred to as PC5 communication) in an NPN will be disclosed.

[0187] In some cases, a UE may implement multiple V2X services, not only in V2X services using Uu communication between a base station and a terminal, but also in V2X services using PC5 communication between terminals. In such cases, the same problem as disclosed in the first embodiment occurs. For example, even if multiple NPNs are constructed in a factory, a problem occurs in that the V2X services using PC5 communication supported by each NPN cannot be made different.

[0188] To address such issues in V2X services using PC5 communication, the method of associating V2X services with NPNs disclosed in the first embodiment may be applied. An NPN that can use the V2X service may be set. One NPN that can use one or more V2X services may be set. One or more NPNs that can use one V2X service may be set. Information that associates information about the V2X service with information about the NPN that can use the V2X service may be used.

[0189] In the first embodiment, a V2X service using Uu communication is disclosed in the sequence examples of Figures 14 and 15. In contrast to this, in the present first modification, a V2X service using PC5 communication is disclosed.

[0190] Scheduling for PC5 communication for a UE is performed by a base station in an NPN that is accessible by the UE performing PC5 communication. One method of PC5 communication is a method in which the base station performs scheduling (hereinafter, sometimes referred to as Mode 1). When implementing a V2X service using Mode 1 PC5 communication, this Modification 1 should be applied.

[0191] As a method for implementing a V2X service using PC5 communication, the method disclosed in the first embodiment may be applied as appropriate. For example, a method of setting an NPN that can use the V2X service, a method of including V2X service information and information about NPNs that can use the V2X service in V2X service-related information, a method of notifying a UE of V2X service information and information about NPNs that can use the V2X service from a PCF, a method of notifying a RAN node (e.g., a gNB) of V2X service information and information about NPNs that can use the V2X service from a PCF, a method in which a UE determines accessible cells using V2X service information and information about NPNs that can use the V2X service, etc. may be applied as appropriate. The V2X service-related information may be, for example, a V2X policy or V2X parameters on a PC5 (also referred to as a 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 a method for setting an NPN that can use the V2X service, information on NPNs that can use the V2X service using Uu communication and information on NPNs that can use the V2X service using PC5 communication may be separated. In the first embodiment, information on NPNs that can use the V2X service using Uu communication may be used. In the present first modification, information on NPNs that can use the V2X service using PC5 communication may be used. In this way, the amount of information on NPNs that can use the V2X service to be used can be reduced.

[0193] The RAN node may verify whether NPN access is possible. The RAN node verifies whether NPN access is possible for the UE. The RAN node may also verify whether NPN access is possible when providing V2X services using PC5 communication. The RAN node verifies whether access is possible to the NPN of its own cell for V2X service access from the UE. If access is possible, the RAN node grants access to the UE and performs scheduling for PC5 communication. If access is not possible, the RAN node does not grant access to the UE. The RAN node may notify the UE of a rejection. The RAN node may notify the UE of reason information included in the rejection.

[0194] The RAN node that performs the NPN accessibility verification for a UE may be a RAN node under the AMF to which the UE is connected. The RAN node may recognize in advance the association between V2X services and NPNs that can use the V2X services. The RAN node may perform the NPN accessibility verification only when the RAN node recognizes in advance the association between V2X services and NPNs that can use the V2X services. The RAN node may determine whether to perform the NPN accessibility verification for a UE depending on whether it recognizes the association between the V2X service and the NPN in response to a V2X service access from the UE. If the RAN node recognizes the association, it performs the NPN accessibility verification. If the RAN node does not recognize the association, it does not perform the NPN accessibility verification and notifies the AMF, and the AMF then performs the NPN accessibility verification for the UE.

[0195] For example, when a UE performs 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 RAN node has already obtained V2X certification and has been provided with a V2X policy. In such cases, it may be unnecessary to verify NPN accessibility in the AMF. By verifying NPN accessibility in the RAN node, signaling between the CN and the RAN node can be reduced. In addition, V2X services can be performed with lower latency than when NPN accessibility is verified in the AMF.

[0196] 16 and 17 are diagrams showing an example of a sequence for performing V2X PC5 communication via the own NPN cell according to the first modification of the first embodiment. FIGS. 16 and 17 are connected at the position of the boundary line BL1617. FIGS. 16 and 17 show an example in which a RAN node (base station) schedules a UE for PC5 communication. 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 the 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 assigned the same step numbers, and common descriptions will be omitted.

[0197] In Step ST1502, the RAN node broadcasts NPN-related information to the UE. The transmitting UE receives the NPN-related information and, in Step ST1504, determines whether or not it is possible to access the RAN node using the received NPN-related information. The receiving UE may receive the NPN-related information broadcast from the RAN node. The transmitting UE may apply the methods disclosed in FIGS. 14 and 15 to determine whether or not it is possible to access the RAN node. If it determines that it is possible to access the RAN node, in Step ST1406, the transmitting UE notifies the RAN node of the NPN-related information and V2X capability. In the examples of FIGS. 16 and 17, the capability of PC5 communication may be used as the V2X capability. The V2X capability may include information indicating that PC5 communication is possible.

[0198] 14 and 15 in the first embodiment may be a capability for Uu communication. In this way, the NW-side node can recognize whether the UE has a capability for Uu communication or a capability for PC5 communication for V2X communication. Furthermore, by the UE notifying the NW side of these capabilities, the NW-side node can recognize whether the UE is requesting authentication for Uu communication and provision of a policy or parameters, or authentication for PC5 communication and provision of a policy or parameters.

[0199] In Step ST1411, if the AMF determines that the transmitting UE is accessible, it recognizes that the V2X service can be provided by using the V2X capability received from the transmitting UE. If the capability of PC5 communication is notified, the AMF can clearly recognize that the V2X service using PC5 communication can be provided. The transmitting UE may notify 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 has clearly requested the provision of the V2X service using PC5 communication.

[0200] In Step ST1413, the AMF notifies the PCF of the V2X capability received from the transmitting UE. For this notification, for example, the AMF may use the Npcf interface or a UE Policy Control Create Request message.

[0201] The transmitting UE may notify the PCF of a V2X policy provision request. The transmitting UE may notify the PCF by including the request in a UE Policy Container (UE Policy Container) to be notified. The transmitting UE may notify the PCF of the request via the AMF. The notification from the transmitting UE to the AMF may be, for example, by using NAS signaling. For example, a transmitting UE policy provision request message may be used. The notification from the AMF to the PCF may be, for example, by using the Npcf interface or a UE Policy Control Update message.

[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. The PCF also decides to provide a V2X policy to the transmitting UE. The PCF may decide to provide a V2X policy using PC5 communication. The PCF also decides to provide a V2X service and information on NPNs that can use the V2X service to the transmitting UE. The PCF may decide to provide a V2X service using PC5 communication and information on NPNs that can use the V2X service. Not only the V2X policy but also V2X policy or V2X parameters may be included. The V2X policy or V2X parameters may include information on the V2X service and NPNs that can use the V2X service.

[0203] In Step ST1415, the PCF notifies the AMF of the 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, a V2X service using PC5 communication occurs in the transmitting UE. If the transmitting UE is not camped on a cell in an NPN that can use the V2X service, in Step ST1523, the UE selects or reselects a cell in the NPN that can use the V2X service. The transmitting UE may use the information on the V2X service and the NPN that can use the V2X service, acquired in Step ST1417, for the selection / reselection. In this way, the transmitting UE can implement the desired V2X service in the NPN to which the transmitting UE is permitted to access.

[0205] In Step ST1530, the transmitting UE notifies the selected / reselected cell of NPN-related information and V2X capability. FIGS. 16 and 17 disclose an example in which, in Step ST1532, a RAN node constituting a cell performs NPN accessibility verification for the transmitting UE. The RAN node uses the NPN-related information notified from the transmitting UE to determine whether the transmitting UE can access its own RAN node. If the RAN node determines that the transmitting UE can access the RAN node, in Step ST1533, it may notify the transmitting UE of a V2X service allowance message using PC5 communication.

[0206] In this way, by having the RAN node verify whether NPN access is possible, when a UE that has information about an NPN that can use V2X services using PC5 communication performs PC5 communication, it does not need to access the core network side, making it possible to reduce the time until PC5 communication can begin.

[0207] If the RAN node reselected by the transmitting UE in Step ST1523 is different from the RAN node from which the V2X communication-related information was received in Step ST1416, the RAN node may request the AMF or PCF to provide the V2X-related information. The RAN node may perform the processes from Step ST1407 to Step ST1416. The RAN node can acquire the V2X-related information for the transmitting UE. In this case, the AMF may also verify whether the UE can access the NPN.

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

[0209] In Step ST1547, the transmitting UE performs PC5-S signaling with the receiving UE using the scheduling information for PC5 communication received from the RAN node in Step ST1535, and establishes a link for PC5 communication. In Step ST1548, the transmitting UE performs RRC signaling with the receiving UE, and mutually notifies each other of, for example, AS layer configuration information and UE capability information. In this way, both the transmitting UE and the receiving UE can configure the AS layer for PC5 communication. The order of PC5-S signaling and RRC signaling may be reversed as appropriate. For example, RRC signaling required to perform PC5-S signaling may be performed before 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 for the V2X service using PC5 communication is performed between the transmitting UE and the receiving UE. In the PC5 communication, the transmitting UE may transmit a BSR to the RAN node multiple times. The BSR may be transmitted as appropriate from PC5-S signaling to V2X service data transmission or until the PC5 link is released. Upon receiving the BSR, the RAN node performs scheduling for PC5 communication and notifies the transmitting UE of scheduling information for PC5 communication. In this way, a RAN node belonging to an NPN capable of providing a V2X service using PC5 communication can perform scheduling for PC5 communication for the UE.

[0211] The method disclosed in this first modification of the first embodiment makes it possible to provide V2X services using PC5 communication in an NPN. A UE can access an NPN that can use the V2X service, but cannot access an NPN that cannot use the V2X service. It is possible to limit the V2X services that can be used in an NPN. It is also possible to perform PC5 communication for V2X services that can be supported for each NPN. It is also possible to prevent PC5 communication for V2X services that cannot be supported for each NPN.

[0212] Variation 2 of Embodiment 1 In this second modification, another method for solving the problem disclosed in the first modification of the first embodiment will be disclosed.

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

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

[0215] The RAN node may broadcast to the UE information associating PC5 communication resources with NPNs that can use the resources. The RAN node may broadcast the information by including it in system information. Alternatively, the RAN node may include the information in system information and notify it by dedicated signaling. The RAN node may notify the information by using a shared channel.

[0216] The RAN node may broadcast information about PC5 communication resources by including it in information about NPNs to be broadcast to the UE. The RAN node may broadcast information associating NPNs with PC5 communication resources. A UE that requires NPN access control can recognize the PC5 communication resources required for performing a V2X service by acquiring the information. Alternatively, the RAN node may broadcast information about an NPN that uses the resources by including it in information about PC5 communication resources to be broadcast to the UE. A UE that performs a V2X service via PC5 communication can recognize an NPN that can perform a V2X service by acquiring the information about PC5 communication resources.

[0217] The UE may acquire in advance V2X service information using PC5 communication and information on NPNs that can use the V2X service. Both the transmitting UE and the receiving UE that perform V2X service using PC5 communication may acquire in advance V2X service information and information on NPNs that can use the V2X service. The method disclosed in the first embodiment or the first modification of the first embodiment may be applied as appropriate. For example, a method may be applied in which the PCF notifies the UE of the V2X service information and information on NPNs that can use the V2X service.

[0218] The UE may store in advance V2X service information using PC5 communication and information on NPNs that can use the V2X service. The method disclosed in the first embodiment may be applied as appropriate.

[0219] A transmitting UE providing a V2X service using PC5 communication may verify whether or not the V2X service using PC5 communication can be implemented within the NPN using previously acquired information about the NPN associated with the V2X service using PC5 communication and information about the NPN broadcast from the RAN node. If the information about the NPN is the same, the transmitting UE determines that PC5 communication is possible and starts PC5 communication using the PC5 communication resources associated with the NPN. If the information about the NPN is different, the transmitting UE determines that PC5 communication is not possible and does not start PC5 communication. The transmitting UE may request PC5 communication resources from the RAN node again.

[0220] In this way, when a transmitting UE implements a V2X service using PC5 communication, it becomes possible to verify whether or not the NPN can be accessed. By verifying whether or not the NPN can be accessed, it becomes possible to disable the V2X service for UEs that cannot access an NPN that can use the V2X service using PC5 communication. It is also possible to implement NPN access restrictions for V2X services using PC5 communication.

[0221] The receiving UE derives PC5 communication resources to be used for the V2X service using previously acquired information about the NPN associated with the V2X service using PC5 communication, and information about the NPN and PC5 communication resource information corresponding to the NPN broadcast from the RAN node. The receiving UE performs reception processing for PC5 communication using the derived PC5 communication resources. This enables the receiving UE to receive PC5 communication from the transmitting UE.

[0222] An RP may be set for each V2X service. Alternatively, an RP may be divided and set for each V2X service. One RP may be divided into multiple sub-RPs. An RP used in an NPN may be set for each NPN. Alternatively, an RP may be divided and set for each NPN. One RP may be divided into multiple sub-RPs. One RP or sub-RP may be used by one or multiple NPNs. An NPN may be associated with an RP used in an NPN. PC5 communication within the same NPN may be performed using an associated RP.

[0223] These may be combined, making it possible to set a V2X service, an NPN that can use the service, and an RP used by the NPN. Although an RP has been disclosed, the RP is merely one example of a resource for PC5 communication. The resource for PC5 communication may be a frequency used for PC5 communication. The resource for PC5 communication is not limited to a frequency, but may also be a band.

[0224] These pieces of setting information may be provided from the CN to the UE. For example, the PCF notifies the UE of these pieces of setting information. The PCF may notify the UE of these pieces of setting information by including them in V2X-related information. For example, the PCF may notify the UE of these pieces of setting information by using a V2X policy provision process. As a method for this, the method disclosed in the first modification of the first embodiment may be applied. These pieces of setting information may be configured in the CN-side node. As a method for configuring the information in the CN-side node, the method disclosed in the first embodiment may be applied as appropriate.

[0225] This makes it possible to set PC5 communication resources to be used for each V2X service or each NPN. Because resources used for PC5 communication can be separated for each V2X service or each NPN, V2X services using PC5 communication can be implemented without interference from other V2X services or other NPNs, such as collisions with other V2X services or communications in other NPNs.

[0226] The transmitting UE may notify the receiving UE of V2X service information using PC5 communication and information about NPNs that can use the V2X service. Alternatively, the transmitting UE may notify either one of the pieces of information. The information about the NPN may be an identifier for identifying the NPN. In this way, the receiving UE can receive this information from the transmitting UE without receiving it from the RAN node. The receiving UE can execute the V2X service using PC5 communication with the transmitting UE.

[0227] The receiving UE may compare previously acquired information about an NPN associated with the V2X service with information about the V2X service using PC5 communication notified by the transmitting UE and information about an NPN that can use the V2X service to verify whether the V2X service using PC5 communication can be implemented between the transmitting UE and the NPN. If the information about the NPN is the same, the receiving UE determines that PC5 communication is possible. Furthermore, the receiving UE receives the V2X service from the transmitting UE using PC5 communication resources associated with the NPN. If the information about the NPN is different, the receiving UE determines that PC5 communication is not possible and does not receive the V2X service.

[0228] 18 and 19 are diagrams showing an example of a sequence for performing V2X PC5 communication via the UE's own NPN cell according to the second modification of the first embodiment. FIGS. 18 and 19 are connected at the boundary line BL1819. FIGS. 18 and 19 show an example in which the UE performs scheduling of PC5 communication. In FIGS. 18 and 19, steps common to those in FIGS. 16 and 17 are assigned the same step numbers, and common explanations will be omitted.

[0229] In Step ST1521, a V2X service using PC5 communication occurs in the transmitting UE. In Step ST1523, the transmitting UE reselects a cell in the NPN that can use the V2X service. In Step ST1629, the transmitting UE receives PC5 communication-related information broadcast from the reselected cell. The PC5 communication-related information may include information about a resource pool (RP) for PC5 communication. The PC5 communication-related information may also include information about the NPN, such as an identifier. The RP may be associated with information about the NPN.

[0230] In this way, the transmitting UE can acquire resources for performing PC5 communication scheduling, and can also acquire information about NPNs that can use V2X services using PC5 communication.

[0231] In the examples of FIGS. 18 and 19 , in Step ST1637, the transmitting UE performs NPN accessibility verification. Using the PC5 communication related information broadcast from the RAN node and the V2X communication related information notified in Step ST1417, the transmitting UE becomes able to recognize the RP corresponding to the NPN that can use the V2X service using the generated PC5 communication. In Step ST1638, the transmitting UE selects the RP corresponding to the NPN that can use the V2X service. The transmitting UE performs scheduling for the PC5 communication using the selected RP.

[0232] If there is no RP corresponding to the NPN that can use the V2X service using the occurred PC5 communication, the transmitting UE determines that the PC5 communication is not possible and does not perform the PC5 communication. In this case, for example, the transmitting UE may again request the AMF or PCF to provide V2X communication-related information. For example, the transmitting UE may perform the processes of steps ST1407 to ST1417. The transmitting UE may perform the processes via the cell reselected in step ST1523. The transmitting UE again reselects a cell in the NPN that can use the V2X service and verifies whether the NPN can be accessed using the PC5 communication-related information broadcast from the cell.

[0233] In this way, by having the transmitting UE verify whether or not NPN access is possible, when a UE that has information about an NPN that can use V2X services using PC5 communication performs PC5 communication, it does not need to access the network side, making it possible to further reduce the time until PC5 communication starts.

[0234] In Step ST1642, the transmitting UE makes a PC5 communication request to the receiving UE. The transmitting UE may make the request using PC5-S signaling. The PC5 communication request may include NPN-related information. The receiving UE can recognize the NPN-related information. In Step ST1645, the receiving UE may transmit a PC5 communication permission to the transmitting UE. 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 PC5 communication to be performed with the receiving UE.

[0235] The receiving UE may also perform the processes from step ST1502 to step ST1417, similarly to the transmitting UE. The receiving UE may also perform the NPN accessibility verification. For example, the receiving UE may perform the process of step ST1629. This allows the receiving UE to check whether the NPN supports the V2X service to be received, using the NPN-related information notified from the transmitting UE in step ST1642. If the NPN supports the V2X service to be received, the receiving UE may notify the NPN of PC5 communication permission in step ST1645, and if not, may notify the NPN of PC5 communication refusal. Alternatively, the receiving UE may not transmit anything. In this way, the desired V2X service can be implemented only in an NPN that can use the desired V2X service using PC5 communication. Furthermore, a UE other than the UE that performs the NPN accessibility determination can perform the NPN accessibility verification.

[0236] If the RAN node reselected by the transmitting UE in Step ST1523 is different from the RAN node from which the V2X communication-related information was received in Step ST1416, the RAN node may request the AMF or PCF to provide the V2X-related information. The RAN node may perform the processes from Step ST1407 to Step ST1416. The RAN node can acquire the V2X-related information for the transmitting UE. In this case, the AMF may also verify whether the UE can access the NPN.

[0237] In this second modification, an example has been disclosed in which a RAN node broadcasts PC5 communication-related information. Even if a UE performing PC5 communication moves out of the coverage of the RAN node, the UE may implement a V2X service using PC5 communication by using the PC5 communication-related information received when the UE was in the coverage. This makes it possible to implement a V2X service using PC5 communication even outside the coverage of the RAN node.

[0238] The method disclosed in this second modification of the first embodiment makes it possible to implement a V2X service using PC5 communication in an NPN. Even when a transmitting UE performing PC5 communication performs scheduling for PC5 communication, it is possible to implement a V2X service using PC5 communication within an NPN. Furthermore, it is possible to implement NPN access restrictions even in V2X services using PC5 communication. Furthermore, since it is not necessary to access a RAN node for scheduling for PC5 communication, it is possible to implement PC5 communication with low latency.

[0239] Modification 3 of Embodiment 1 One method of PC5 communication is that the transmitting UE that performs PC5 communication performs scheduling. Resources for PC5 communication may be configured in advance in the UE. When PC5 communication is performed using resources for PC5 communication configured in advance in the UE, access from the UE to the network side is not required. For example, even if the UE is not within the coverage of a cell belonging to its own NPN, the UE can perform PC5 communication.

[0240] However, in a conventional NPN, the UE determines whether or not access is possible based on information received from the cell, and the UE accesses the AMF via the cell, and the AMF verifies whether or not access is possible. Therefore, if the UE cannot find a cell belonging to its own NPN, access control cannot be performed, and the UE cannot determine whether PC5 communication is possible, and PC5 communication becomes impossible.

[0241] In this third modification, a method for solving such problems will be disclosed.

[0242] PC5 communication can be performed even when the UE does not use a cell belonging to its own NPN as a serving cell. V2X services using PC5 communication can be performed. Even if the UE is configured to be able to communicate only with its own CAG, it may be possible to perform PC5 communication outside its own CAG. V2X services using PC5 communication can be performed.

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

[0244] In this way, the UE can perform PC5 communication even when the UE does not use a cell belonging to its own NPN as the serving cell.

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

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

[0247] The UE may determine whether the V2X service to be implemented is a V2X service using PC5 communication using PC5 communication resources configured in advance in the UE, using information indicating whether PC5 communication is possible outside a cell belonging to the own NPN. This makes it possible for the UE to control whether PC5 communication is possible outside a cell belonging to the own NPN.

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

[0249] By doing so, even when it is clear that many UEs using PC5 communication to provide V2X services do not use a cell belonging to their own NPN as a serving cell, PC5 communication can be performed, making it possible to reduce malfunctions in communication between UEs.

[0250] As described above, PC5 communication resources used when a cell belonging to the own NPN is not used as the serving cell may be configured in advance in the UE. This is suitable for cases where PC5 communication resource information is not notified to the UE from the PCF. As another example, the resources used to perform PC5 communication may be PC5 communication resources most recently provided by the CN. This is suitable for cases where the UE can access the CN. For example, if the UE is previously in a state where it is within the coverage of a cell belonging to the own NPN, it receives V2X service authentication and V2X policy provision for the V2X service via the own NPN cell, and acquires PC5 communication resources. In this way, using the PC5 communication resources provided by the CN, PC5 communication can be performed even outside the own NPN.

[0251] An expiration date may be set for the PC5 communication resources. The PC5 communication resources are usable within the expiration date, and are made unusable after the expiration date. The expiration date may be managed by a timer. Information about the expiration date (which may be timer information) may be statically determined by a standard or the like, or may be configured in the UE in advance. Alternatively, information about the expiration date (which may be timer information) may be provided by the CN when the UE is able to access the CN. In this way, the UE can recognize the PC5 communication resources that can be used when a cell belonging to the own NPN is not used as the serving cell.

[0252] 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. PC5 communication resources used in an NPN may be set for each NPN. A combination of these may also be used. The PC5 communication resources may be an RP. Or one or more RPs. This setting information may be stored in the UE. This setting information may be provided from the CN when the UE is able to access the CN. For example, the PCF notifies the UE of this setting information. The setting information may be notified by being included in V2X-related information. For example, the setting information may be notified using a V2X policy provision process. As these methods, the method disclosed in the second modification of the first embodiment may be applied.

[0253] When a UE does not use a cell belonging to its own NPN as a serving cell and when PC5 communication is performed between UEs, the NPN access control of conventional Uu communication cannot be used, and a problem occurs in which NPN access control such as NPN access permission determination by the UE and access permission verification by AMF cannot be performed. Also, this causes a problem in that a UE performing PC5 communication communicates with a UE outside its own NPN. A method for solving such a problem is disclosed.

[0254] A transmitting UE in PC5 communication notifies a receiving UE of its own NPN-related information. The NPN-related information may be an identifier for identifying 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 V2X service information.

[0256] Alternatively, the NPN-related information may be notified in the V2X layer. The NPN-related information may be notified by PC5-S signaling. The NPN-related information may be notified when a Layer 2 link for PC5 communication is established between UEs. For example, the transmitting UE may include the NPN-related information in a Direct Communication Request and notify the receiving UE of the NPN-related information. The V2X layer converts the 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 in advance from the CN to the UE. Alternatively, the information may be configured in the UE in advance.

[0257] Alternatively, 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 an RRC link for PC5 communication is established between UEs. For example, the transmitting UE may notify the receiving UE of the NPN-related information by including it in a UE capability inquiry notification or a UE capability information notification. For example, the transmitting UE may notify the receiving UE of the NPN-related information by including it in a PC5 communication configuration information (Configuration Message) notification or a PC5 communication configuration completion notification.

[0258] Other notification methods at the AS layer are disclosed. The NPN-related information may be notified in a synchronization procedure. The NPN-related information may be notified, for example, by being included in a PSBCH or an SL-BCH. As another method, the NPN-related information may be notified in a discovery procedure. The NPN-related information may be notified, for example, by being included in a PSDCH. As another method, the NPN-related information may be notified in PC5 communication. The NPN-related information may be notified, for example, by being included in a PSSCH or an SL-SCH. Furthermore, the NPN-related information may be notified, for example, by being included in a PSCCH or an SCI.

[0259] In this way, NPN-related information can be communicated between UEs performing PC5 communication.

[0260] A V2X service may be associated with an NPN that can use the service. A V2X service may be associated with an NPN to which the UE belongs among NPNs that can use the service (sometimes referred to as the user's own NPN). By associating a V2X service with an NPN to which the UE belongs among NPNs that can use the service, if the V2X service is supported by multiple different NPNs, it becomes possible to associate the V2X service with a specific NPN among the NPNs. The specific NPN can be the NPN to which the user's own UE belongs. The user's own UE may belong to one or more NPNs.

[0261] UEs performing PC5 communication may notify each other of information associating a V2X service with their own NPNs that can use the service. A transmitting UE performing PC5 communication may notify a receiving UE of information associating a V2X service with their own NPNs that can use the service.

[0262] A method for associating a V2X service with a local NPN that can use the service is disclosed.

[0263] V2X service information and NPN-related information are associated with each other. It is preferable to set an NPN that can use the V2X service. It is also possible to set one NPN that can use one or more V2X services. It is also possible to set one or more NPNs that can use one V2X service. It is also possible to have information that associates V2X service information with information on NPNs that can use the V2X service.

[0264] For example, an identifier for identifying a V2X service is associated with an identifier for identifying an NPN. This association may be performed in the V2X application layer. This is effective when the V2X application layer recognizes the association between the V2X service and the NPN that can use the service. Information on the association between the V2X service and the NPN that can use the service may be notified between UEs as signaling or data in the V2X application layer described above.

[0265] Another method is disclosed. The V2X application layer notifies the V2X layer of association information between a V2X service and an NPN that can use the service. This method is effective when the V2X application layer recognizes the association between a V2X service and an NPN that can use the service. Alternatively, the V2X layer may associate a V2X service with an NPN that can use the service. This method is effective when the V2X layer recognizes the association between a V2X service and an NPN that can use the service.

[0266] Since V2X service information is converted into a Layer 2 identifier in the V2X layer, it is preferable to associate this Layer 2 identifier with NPN-related information. The Layer 2 identifier may be a Layer 2 identifier used for broadcast communication, 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 a V2X service with an NPN that can use the service. Information on the association between a V2X service and an NPN that can use the service may be notified between UEs as signaling or data in the V2X layer described above. PC5-S signaling may be used for this notification.

[0267] Another method is disclosed. The V2X layer notifies the AS layer of association information between V2X services and NPNs that can use them. This method is effective when the V2X layer recognizes the association between V2X services and NPNs that can use them using the method described above. Alternatively, the AS layer may associate V2X services with NPNs that can use them. This method is effective when the AS layer recognizes the association between V2X services and NPNs that can use them. The V2X layer may notify the AS layer of a Layer 2 identifier, and the AS layer may associate the Layer 2 identifier with NPN-related information.

[0268] In this way, it becomes possible for UEs providing V2X services using PC5 communication to communicate their own NPN-related information with each other.

[0269] A receiving UE performing PC5 communication receives V2X service information notified from a transmitting UE and NPN-related information to which a transmitting UE that can use the V2X service belongs. Thus, the receiving UE acquires the desired V2X service and NPN-related information to which a transmitting UE that can use the service belongs. The receiving UE may determine whether or not the transmitting UE can access the NPN. The receiving UE may determine whether or not the NPN can be accessed using the NPN-related information to which the transmitting UE belongs, notified from the transmitting UE.

[0270] For example, the receiving UE compares the NPN-related information to which the transmitting UE belongs, notified by the transmitting UE, with information about the V2X service and the NPNs that can use it, configured in advance in the UE. 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 not possible and does not communicate with the transmitting UE. If the receiving UE determines that access is not possible, it may perform the process of detecting a PC5 communication request from the transmitting UE again, including information about the desired V2X service and the NPNs that can use it.

[0271] The receiving UE may notify the transmitting UE of the access permission judgment result. For example, the receiving UE may send a PC5 communication accept to the transmitting UE. The receiving UE may include its own NPN-related information in the PC5 communication accept message. The transmitting UE may perform NPN access permission verification using the NPN-related information to which the receiving UE belongs, received from the receiving UE.

[0272] For example, the transmitting UE compares the NPN-related information to which the receiving UE belongs, notified by the receiving UE, with the NPN-related information transmitted by its own UE. If the same NPN is found, the transmitting UE determines that the NPN is accessible and communicates with the receiving UE. If the same NPN is not found, the transmitting UE determines that the NPN is inaccessible and does not communicate with the transmitting UE. In this way, the transmitting UE verifies whether or not the NPN can be accessed.

[0273] In the above description, it has been disclosed that the receiving UE makes the access permission determination and the transmitting UE performs the access permission verification. Alternatively, the access permission verification may be performed by the above-mentioned access permission determination by the receiving UE. The access permission verification is performed in the receiving UE.

[0274] In this way, it becomes possible to perform access control in the NPN between UEs that perform V2X services using PC5 communication. It becomes possible to perform V2X services using PC5 communication between UEs that belong to the same NPN. It is also possible to make it impossible to perform V2X services using PC5 communication between UEs that belong to different NPNs.

[0275] Fig. 20 is a diagram showing a first example of a sequence for performing PC5 communication outside the coverage of the cell to which the own NPN belongs, in accordance with Modification 3 of Embodiment 1. Fig. 20 shows an example in which a UE performs scheduling of PC5 communication. Fig. 20 also shows an example in which a transmitting UE performs NPN accessibility verification. In Fig. 20, steps common to Fig. 18 and Fig. 19 are assigned the same step numbers, and common explanations will be 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 its own UE belongs. In Step ST1739, the transmitting UE derives the V2X service and the NPN that can use the V2X service. This derivation may use information about the NPN that can use the V2X service, which is configured in advance in the transmitting UE.

[0277] The transmitting UE derives an NPN compatible with the V2X service and derives PC5 communication resources available for the derived NPN. This derivation can be performed using information on PC5 communication resources available for the NPN that is configured in advance within the transmitting UE.

[0278] In this way, 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 related to NPN may be included in the PC5 communication request. This allows the receiving UE to recognize NPN-related information.

[0279] In Step ST1743, the receiving UE may determine whether or not to allow access based on the identifier of the NPN. The receiving UE can check whether or not the NPN supports the V2X service to be received by using information about NPNs that can use the V2X service, which is configured in advance in the receiving UE, and the NPN-related information notified from the transmitting UE in Step ST1642. If the NPN supports the V2X service to be received, the receiving UE may notify the NPN of PC5 communication permission in Step ST1645, and if not, may notify the NPN of PC5 communication denial. Alternatively, the receiving UE may not transmit anything.

[0280] In step ST1645, the receiving UE transmits a PC5 communication permission to the transmitting UE. The PC5 communication permission may include NPN-related information. In step ST1746, if the transmitting UE receives the PC5 communication permission from the receiving UE, it determines that the PC5 communication is possible; otherwise, it determines that the PC5 communication is not possible. The transmitting UE may further use the NPN-related information included in the PC5 communication permission to determine whether or not the PC5 communication is possible. If the NPN-related information included in the PC5 communication permission includes an NPN that can use the V2X service using PC5 communication, the transmitting UE determines that the PC5 communication is possible. Otherwise, the transmitting UE determines that the PC5 communication is not possible.

[0281] In this way, if the NPN cannot use the desired V2X service, PC5 communication can be disabled. The transmitting UE can verify whether the NPN can be accessed.

[0282] Fig. 21 is a diagram showing a second example of a sequence for performing PC5 communication outside the coverage of the cell to which the own NPN belongs, in accordance with the third modification of the first embodiment. Fig. 21 shows an example in which the UE performs scheduling of the PC5 communication. Fig. 21 also shows an example in which the transmitting UE does not perform NPN accessibility verification, but the receiving UE performs NPN accessibility verification. In Fig. 21, steps common to Fig. 20 are assigned the same step numbers, and common explanations will be omitted.

[0283] In Step ST1844, the receiving UE may verify whether or not the access is permitted using the identifier of the NPN. The receiving UE can check whether or not the NPN supports the V2X service to be received by using information about NPNs that can use the V2X service, which is configured in advance in the receiving UE, and the NPN-related information notified from the transmitting UE in Step ST1642. If the NPN supports the V2X service to be received, the receiving UE may notify the NPN of PC5 communication permission in Step ST1645, and if not, may notify the NPN of PC5 communication denial. Alternatively, the receiving UE may not transmit anything.

[0284] In this way, the desired V2X service can be implemented only in an NPN that can use the desired V2X service using PC5 communication. If the NPN cannot use the desired V2X service, PC5 communication can be disabled. The receiving UE can verify whether or not the NPN can access the V2X service. This eliminates the need for the transmitting UE to verify whether or not the NPN can access the V2X service.

[0285] The transmitting UE may determine whether or not NPN access is possible before transmitting a PC5 communication request. The determination of whether or not PC5 communication can be performed may also be used as a determination of whether or not NPN access is possible. As a determination indicator, for example, information on whether or not the UE already possesses resources for PC5 communication for the V2X service to be performed may be used. The transmitting UE determines that PC5 communication is possible when a cell belonging to its own NPN is not used as a serving cell and when the transmitting UE possesses resources for PC5 communication for the V2X service to be performed. The transmitting UE determines that PC5 communication is not possible when a cell belonging to its own NPN is not used as a serving cell and when the transmitting UE does not possess resources for PC5 communication for the V2X service to be performed.

[0286] As a judgment index, for example, information on whether the V2X service to be implemented can be implemented in the NPN to which the UE belongs may be used. If the V2X service to be implemented can be implemented in the NPN to which the UE belongs, the transmitting UE determines that PC5 communication can be implemented. If the V2X service to be implemented cannot be implemented in the NPN to which the UE belongs, the transmitting UE determines that PC5 communication can be implemented.

[0287] The above-mentioned judgment indicators may also be used. For example, if the V2X service to be implemented can be implemented in the NPN to which the UE belongs and the UE has resources for PC5 communication for the V2X service, the UE is deemed to be able to communicate via PC5. If not, the UE is deemed to be unable to communicate via PC5.

[0288] In this way, the transmitting UE can perform the process of determining whether NPN access is possible. The determination of whether NPN access is possible in the transmitting UE may be applied to, for example, the example disclosed in FIG. 20. In FIG. 20, the transmitting UE performs the above-mentioned determination of whether NPN access is possible in the transmitting UE before transmitting the PC5 communication request in step ST1642. If the transmitting UE determines that NPN access is possible and that PC5 communication is possible, the transmitting UE transmits the PC5 communication request. If the transmitting UE determines that NPN access is not possible and that PC5 communication is not possible, the transmitting UE does not transmit the PC5 communication request.

[0289] In this way, it becomes possible for the transmitting UE to perform the process of determining whether or not NPN access is possible in the example of Fig. 20. If the transmitting UE determines that NPN access is not possible, it will not transmit a PC5 communication request, which eliminates the wasteful use of resources in PC5 communication and reduces interference.

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

[0291] In this way, it becomes possible for the transmitting UE to perform the process of determining whether or not NPN access is possible in the example of Fig. 21. If the transmitting UE determines that NPN access is not possible, it will not transmit a PC5 communication request, which eliminates the wasteful use of resources in PC5 communication and reduces interference.

[0292] In the example of Fig. 21, by adding the process of determining whether or not to allow NPN access by the transmitting UE, it is possible to differentiate the UE that performs the process of determining whether or not to allow NPN access from the UE that performs the verification of whether or not to allow NPN access. This makes it possible to perform NPN access control with multiple different UEs.

[0293] Furthermore, since it becomes possible to implement access control in a UE that performs PC5 communication, it is possible to solve the problem that a UE that performs PC5 communication communicates with a UE outside its own NPN.

[0294] A method has been disclosed that enables PC5 communication when a UE cannot find a cell belonging to its own NPN. As an alternative method, when a UE cannot find a cell belonging to its own NPN, PC5 communication may be prohibited. In this way, there is no need to control access to the NPN for the UE. This simplifies the processing of a system using an NPN.

[0295] The method disclosed in this third modification of the first embodiment enables PC5 communication even when the UE cannot find a cell belonging to its own NPN, making it possible to implement V2X services using PC5 communication.

[0296] Variation 4 of Embodiment 1 PC5 communication is communication between UEs. For this reason, it is required to enable PC5 communication, which is communication between UEs, even when the UE is located within the coverage of a cell belonging to another NPN. In this fourth modification, a method is disclosed for enabling PC5 communication even when the UE is located within the coverage of a cell belonging to another NPN.

[0297] A UE performing PC5 communication is permitted to access a cell other than its own NPN. A UE performing PC5 communication determines whether it can access a cell other than its own NPN. For example, a UE determines whether it can access a cell other than its own NPN by determining whether it has V2X capability. A UE may determine whether it has PC5 communication capability. If it has PC5 communication capability, it may access a cell other than its own NPN. If it does not, the UE does not access a cell other than its own NPN. A UE performing PC5 communication can determine whether it can access a cell other than its own NPN even when V2X service is not occurring. A UE performing PC5 communication is enabled to perform V2X authentication and V2X policy provision processing via a cell other than its own NPN in advance.

[0298] Access permission or denial may be different depending on the type of NPN to which a cell different from the own NPN belongs. For example, access is not permitted to a cell belonging to an S-NPN different from the NPN to which a UE performing PC5 communication belongs. Access is permitted to a cell belonging to an NS-NPN different from the NPN to which a UE performing PC5 communication belongs. In this way, even in PC5 communication, access to a different S-NPN can be prohibited. This makes it possible to restrict access to UEs that do not belong to the S-NPN.

[0299] Also, for example, it is possible to allow access to cells belonging to an S-NPN different from the NPN to which the UE performing PC5 communication belongs, and not allow access to cells belonging to an NS-NPN different from the NPN to which the UE performing PC5 communication belongs. By doing so, even if it is PC5 communication, access to a different NS-NPN can be prohibited. Therefore, it is possible to restrict access to UEs that do not belong to the NS-NPN.

[0300] There are cases where one PLMN is one S-NPN and cases where one PLMN is made up of multiple S-PLMNs. For example, it is possible to allow access to cells belonging to different NPNs of the same PLMN as the NPN to which the UE performing PC5 communication belongs, and not allow access to cells belonging to other different NPNs. In this way, even for PC5 communication, it is possible to limit the NPNs that are allowed access. It is also possible to limit the UEs that can access.

[0301] The UE may determine whether the V2X service to be implemented is a V2X service using PC5 communication. If the V2X service uses PC5 communication, the UE may access a cell other than the NPN of the UE. If not, the UE does not access a cell other than the NPN of the UE. If a V2X service using PC5 communication occurs, the UE can access a cell other than the NPN of the UE. Furthermore, if a V2X service using PC5 communication occurs, the UE can perform V2X authentication and V2X policy provision processing via a cell other than the NPN of the UE.

[0302] A RAN node (such as a gNB) may not perform access control of the NPN when a UE accesses it. Conventionally, in NPN access control, the UE determines whether or not to allow access, and the AMF verifies whether or not to allow access. Even when a UE performing PC5 communication accesses a cell different from its own NPN, the RAN node may not perform access control of the NPN. The RAN node may notify the AMF of information received from the UE.

[0303] Alternatively, the RAN node may perform access control of the NPN when a UE accesses the RAN node. 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 notifies the RAN node of the PC5 communication capability by including it in a notification to the RAN node. This allows the RAN node to determine whether the UE is capable of PC5 communication.

[0304] If the notification from the UE includes PC5 communication capability, the RAN node determines that access is possible and allows the UE access. If the RAN node allows the UE access, it may notify the AMF of the PC5 communication capability. Otherwise, the RAN node determines that access is not possible and does not allow the UE access. If the UE access is not allowed, the RAN node may notify the UE of a rejection. The rejection may include cause information.

[0305] When the notification from the UE includes PC5 communication capability, the RAN node may determine that access is possible and may transmit a grant for requesting V2X service-related information to the UE. The UE may notify the AMF of the V2X service-related information provision request using an NAS message. The RAN node may transmit a grant for the NAS message that the UE notifies the AMF. In this way, when a V2X service using PC5 communication occurs for the UE, it becomes possible to perform V2X authentication and V2X policy provision processing via a cell different from the own NPN.

[0306] Furthermore, for example, the RAN node may determine whether the UE has accessed the RAN node to perform a V2X service or to perform a V2X service using PC5 communication. When accessing the RAN node for a V2X service, the UE notifies the RAN node of its PC5 communication capability by including it in a notification to the RAN node. This enables the RAN node to determine whether the UE is capable of PC5 communication.

[0307] A UE performing PC5 communication is permitted to access the AMF via a cell different from its own NPN. The AMF may perform access control of 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 performing 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 access from a UE uses PC5 communication will be disclosed. The AMF may determine whether access from the UE uses PC5 communication by determining whether signaling notified from the UE via a RAN node includes PC5 communication capability. If the notification from the UE includes PC5 communication capability, the AMF determines that access is possible and allows the UE access. If the UE access is allowed, the AMF may request the PCF to authenticate the V2X service and provide the UE with a V2X policy. Otherwise, the AMF determines that access is not possible and does not allow the UE access. If the UE access is not allowed, the AMF may notify the UE of a rejection. The rejection may include cause information.

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

[0310] For a UE performing PC5 communication, V2X authentication and V2X policy provision processing can be performed via a cell different from the own NPN. Using the above-mentioned method, the UE and PCF performing PC5 communication can perform V2X authentication and V2X policy provision processing.

[0311] When an AMF permits access of a UE performing PC5 communication that belongs to an NPN different from the NPN to which the AMF belongs, registration from the UE to the AMF may be unnecessary. When a UE accesses a network via a cell different from the NPN to which the AMF belongs, registration may be unnecessary. In this way, the UE can perform only V2X service authentication using PC5 communication and provision of V2X service-related information.

[0312] When the UE performing the PC5 communication accesses the NW through a cell different from its own NPN, the registration management state may be a non-registered state. When the UE performing the PC5 communication accesses the NW through a cell different from its own NPN, the connection management state may be an idle state. These state managements are performed by the UE and the AMF.

[0313] A state to be managed may be provided in multiple UEs performing PC5 communication. For example, an RRC state may be provided to manage whether or not an RRC connection is established between UEs performing PC5 communication. For example, a link connection management state may be provided to manage whether or not a PC5-S link is established between UEs performing PC5 communication. This facilitates state transition processing in UEs performing PC5 communication, and reduces malfunctions.

[0314] Another method is disclosed. When the access from the UE is for implementing 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. If the determination result indicates that the access from the UE is for implementing a V2X service using PC5 communication, the AMF may request the PCF to perform V2X service authentication and provide a V2X policy to the UE, notify the UE of the V2X policy provided by the PCF in response to the request, and then perform NPN access control for the UE.

[0316] An example of NPN access control for a UE is disclosed. When an access from a UE is to an NPN that is the same as the UE's own NPN, the AMF determines that the access is possible and allows the UE access. When an access from a UE is to an NPN that is different from the UE's own NPN, the AMF determines that the access is impossible and does not allow the UE access. When the UE access is not allowed, the AMF may notify the UE of a rejection. The rejection may include cause information.

[0317] The AMF may provide the V2X policy for the UE by including it in the reject 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] In this way, before the UE is determined to be inaccessible by the NPN access control in 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 V2X policy provision.

[0319] Scheduling for PC5 communication for the UE is performed by a RAN node of an NPN different from the NPN of the UE. In other words, a V2X service using Mode 1 PC5 communication is implemented. To implement a V2X service using Mode 1 PC5 communication, 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 NPN access control method described above may be applied. Furthermore, the V2X policy provision method described above may be applied as appropriate. The V2X policy may be provided from the PCF to the RAN node accessed by the UE, rather than from the PCF to the UE.

[0320] As described above, the V2X service-related information may include information associating information related to NPNs that can use the V2X service. The V2X service-related information may include a V2X policy or V2X parameters, V2X service information, and information about NPNs that can use the V2X service. The V2X policy or V2X parameters may also include the V2X service information and V2X parameters of the NPNs that can use the V2X service. The V2X service-related information may be a V2X policy or V2X parameters that include the V2X service information and V2X parameters of the NPNs that can use the V2X service. The V2X policy or V2X parameters may be, for example, a V2X policy or V2X parameters on a PC5 (also referred to as a PC5 reference point).

[0321] This paper describes a method for a UE to perform PC5 communication. When a V2X service using PC5 communication occurs in a UE, the UE establishes an RRC connection with a RAN node. The RAN node may belong to an NPN different from the NPN of the UE. The RAN node may apply the access control method described above when a UE belonging to an NPN different from its own NPN accesses the RAN node. This allows the UE to 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 MAC signaling. In the case of RRC signaling, the BSR may be notified, for example, by being included in a UE assistance information message. Also, for example, the BSR may be notified in the RRC connection establishment procedure.

[0323] The UE may notify information indicating a scheduling request for PC5 communication instead of a BSR. In this case, the base station cannot recognize the data volume of the V2X service from the UE. The base station may perform scheduling according to a predetermined data volume and notify the UE of the scheduling information. The predetermined data volume may be determined in advance. The UE may perform scheduling according to the data volume that can transmit at least a BSR and notify the UE of the scheduling information.

[0324] In this way, the RAN node can recognize that a UE that does not belong to its own NPN is requesting scheduling for PC5 communication. The RAN node can schedule PC5 communication for a UE that does not belong to its own NPN and notify the UE of the scheduling information.

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

[0326] (1) Information about RATs.

[0327] (2) Frequency information.

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

[0329] (4) Resource allocation information.

[0330] (5) MCS information.

[0331] (6) Information about HARQ.

[0332] (7) Information about CSI.

[0333] (8) Information about transmission power.

[0334] (9) Information regarding power measurements.

[0335] (10) A combination of (1) to (9).

[0336] The information about the RAT in (1) above may be information indicating the RAT used for PC5 communication. The information indicating the RAT may be, for example, information indicating whether the RAT is LTE or NR.

[0337] The resource allocation information in (4) above may be, for example, resource allocation information for each channel used in PC5 communication, or resource allocation information for a reference signal (RS). Examples of channels include PSCCH and PSSCH. The resource allocation information may also be allocation information for resources on frequency and time. 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. The resource allocation information for an RS may also include sequence information used for the RS.

[0338] The information related to HARQ in (6) above includes, for example, the number of repetitions, resource allocation information for repeated transmission, and scheduling information for transmitting HARQ feedback (e.g., Ack and / or Nack). The scheduling information for PC5 communication described above may be applied as scheduling information for repeated transmission or HARQ feedback transmission. Furthermore, the resource allocation information may be a transmission band or a transmission timing. In this way, a transmitting UE performing PC5 communication can perform HARQ processing. Furthermore, a receiving UE performing PC5 communication can perform scheduling for transmitting HARQ feedback.

[0339] The transmitting UE may notify the receiving UE of scheduling information for HARQ feedback using PC5 communication. By receiving the scheduling information for HARQ feedback, the receiving UE becomes able to transmit HARQ feedback.

[0340] The CSI-related information in (7) above is, for example, configuration information of the CSI RS on PC5, scheduling information for CSI report transmission, etc. The configuration information may be the resource allocation information described above. The scheduling information for PC5 communication described above may be applied as the scheduling information for CSI report transmission. Furthermore, the resource allocation information may be a transmission band or a transmission timing. In this way, a transmitting UE performing PC5 communication can transmit a CSI RS. Furthermore, a receiving UE performing PC5 communication can report CSI.

[0341] The transmitting UE may notify the receiving UE of scheduling information for CSI report transmission using PC5 communication. The receiving UE receives the scheduling information for CSI report and is thereby enabled to transmit the CSI report.

[0342] The information regarding transmission power in (8) above 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. The information may also 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 report. Alternatively, the information may be a parameter value for deriving the transmission power by the receiving UE. The base station can set the transmission power taking into account the interference that the transmitting UE and receiving UE receive from other UEs, or the interference that the transmitting UE and receiving UE cause to other UEs.

[0343] The information related to power measurement in (9) above is, for example, configuration information for a power measurement channel or RS on PC5, scheduling information for transmitting a power measurement result report, etc. The configuration information may be the resource allocation information described above. The scheduling information for PC5 communication described above may be applied as the scheduling information for transmitting a power measurement result report. Furthermore, the resource allocation information may be a transmission band or a transmission timing. In this way, a transmitting UE performing PC5 communication can transmit an RS for power measurement. Furthermore, a receiving UE performing PC5 communication can report a power measurement result.

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

[0345] Information notified from a transmitting UE to a receiving UE or information notified from a receiving UE to a 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 SCI and notified on a PSCCH, or may be notified on a feedback channel (PSFCH).

[0346] Using PC5-S signaling allows for early notification. Using RRC signaling allows for notification at the AS layer. For example, this is effective for notifying AS layer information. Using MAC signaling allows for low-latency notification. Also, applying HARQ to MAC signaling can reduce the error rate. Using PSCCH or PSFCH allows for low-latency notification.

[0347] A different notification method may be used for each piece of information. For example, configuration information for the RS for power measurement in PC5 communication may be notified by PC5-S signaling, and the power measurement results may be notified by RRC signaling. In this way, the receiving UE can perform power measurement early and notify the transmitting UE of the power measurement results early after RRC connection is established. This allows the transmitting UE to perform appropriate transmit power control early. By appropriately using a different notification method 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 V2X service information using PC5 communication and information on NPNs that can use the V2X service. Alternatively, the transmitting UE may notify any one of the pieces of information. The receiving UE may determine whether to allow access to the NPN using information on the NPN associated with the V2X service that has been acquired in advance, and the V2X service information using PC5 communication and information on NPNs that can use the V2X service that have been notified by the transmitting UE. The method disclosed in the third modification of the first embodiment may also be applied.

[0349] The receiving UE may notify the transmitting UE of the access permission determination result. For example, the receiving UE may send a PC5 communication accept to the transmitting UE. The receiving UE may include its own NPN-related information in the PC5 communication accept message. The transmitting UE may perform NPN access permission verification using the NPN-related information to which the receiving UE belongs, received from the receiving UE. The method disclosed in the third modification of the first embodiment may also be applied. In this way, the transmitting UE can perform NPN access permission verification.

[0350] Alternatively, the method disclosed in the third modification of the first embodiment may be applied, and the access permission verification may be performed by the above-described access permission determination by the receiving UE. The access permission verification is performed by the receiving UE.

[0351] This makes it possible to perform NPN access control 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.The receiving UE that performs PC5 communication can determine whether to allow NPN access.

[0352] Figures 22 and 23 are diagrams showing an example of a sequence for performing PC5 communication via a cell that does not belong to the own NPN, in accordance with the fourth modification of the first embodiment. Figures 22 and 23 are connected at the position of boundary line BL2223. Figures 22 and 23 show an example in which a RAN node (base station) schedules PC5 communication for a UE. In Figures 22 and 23, steps that are common to Figures 16, 17, and 20 are assigned the same step numbers, and common explanations will be omitted.

[0353] In Step ST1905, the transmitting UE determines whether or not it can access a cell that does not belong to its own NPN. In the case of access for a V2X service using PC5 communication, the transmitting UE determines that it can access a cell that does not belong to its own NPN, and otherwise determines that it cannot access the cell. The RAN node may broadcast NPN-related information to the UE, and the UE receives the broadcasted NPN-related information. In Step ST1905, the UE determines that it can access the RAN node in the case of access for PC5 communication, even if its own NPN is not included in the received NPN-related information.

[0354] If the UE determines that it can access the RAN node, in Step ST1908, it accesses the RAN node and notifies the RAN node of its V2X capability. In Step ST1909, the RAN node notifies the AMF of the V2X capability received from the UE. The method of notifying the AMF of the V2X capability from the transmitting UE may be any of the methods disclosed in Figs. 16 and 17, as appropriate.

[0355] The AMF does not verify whether the UE can access the NPN. For UEs that have notified the V2X capability for PC5 communication, the AMF does not determine whether the UE can access the NW. The AMF uses the V2X capability received from the UE to recognize that it can provide V2X services.

[0356] In Step ST1413, the AMF notifies the PCF of the V2X capability received from the UE. For this notification, for example, the AMF may use the Npcf interface or a UE Policy Control Create Request message.

[0357] In Step ST1414, the PCF performs V2X service authentication using the registration data of the UE. The PCF also decides to provide a V2X policy to the UE. The PCF also decides to provide information on the V2X service and the NPNs that can use the service to the UE. The V2X policy may include V2X parameters. The V2X policy may include information on the V2X service and the NPNs that can use the service.

[0358] In Step ST1415, the PCF notifies the AMF of the V2X communication related information. In Step ST1416, the AMF notifies the RAN node of the V2X communication related information received from the PCF. The AMF may notify the UE of the V2X communication related information received from the PCF. The AMF may notify the UE of the V2X communication related information, for example, by steps ST1416 and ST1417. In Step ST1417, the RAN node notifies the UE of the V2X communication related information. In this way, the UE can also acquire the V2X communication related information.

[0359] In Step ST1521, a V2X service using PC5 communication occurs in the transmitting UE. Even if the transmitting UE is within the coverage of a cell that does not belong to its own NPN, in Step ST1534 the transmitting UE notifies the cell of a BSR for PC5 communication. In Step ST1535, the RAN node that has received the BSR for PC5 communication performs PC5 communication scheduling for the transmitting UE. In Step ST1739 to Step ST1552, the method disclosed in FIG. 20 may be applied as appropriate.

[0360] In this way, even if the UE is within the coverage of a cell that does not belong to its own NPN, it can perform PC5 communication via that cell.

[0361] The method disclosed in this fourth modification of the first embodiment enables the UE to perform PC5 communication even when it cannot find a cell belonging to its own NPN. The UE can perform PC5 communication even when it can only find cells different from its own NPN. V2X services using PC5 communication can be implemented. Furthermore, the UE can perform V2X service authentication and V2X policy provision 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 update the V2X policy even when it can only find cells different from its own NPN. This also enables QoS parameters to be updated. The latest communication status and network load status can be reflected in the V2X policy.

[0362] Variation 5 of Embodiment 1 In this fifth modification, another method for solving the problem disclosed in the fourth modification of the first embodiment will be disclosed.

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

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

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

[0366] In this way, when a UE performing PC5 communication is present within the coverage of a cell that belongs to an NPN different from that of the UE itself, PC5 communication can be performed.

[0367] However, a cell belonging to an NPN different from the one to which the UE belongs does not necessarily broadcast PC5 communication resources available in the NPN to which the UE belongs. As a result, the UE cannot perform PC5 communication using PC5 communication resources broadcast from a cell belonging to an NPN different from the UE's own. This invention discloses a method for solving this problem.

[0368] The PC5 communication resources available in the NPN to which the UE belongs may be configured in advance in the UE. The method of setting the NPN and the PC5 communication resources available in the NPN may be the method disclosed in the second modification of the first embodiment. Furthermore, the PC5 communication resources may be set for each V2X service. The method of setting the NPN and the PC5 communication resources available in the NPN may be the method disclosed in the second modification of the first embodiment.

[0369] In this way, even if the PC5 communication resources broadcast from a cell belonging to an NPN different from that of the UE itself are unavailable in the NPN to which the UE itself belongs, the UE can perform PC5 communication by scheduling using the PC5 communication resources configured in the UE itself, thereby enabling V2X services using PC5 communication to be implemented.

[0370] When the PC5 communication resources are configured in advance in the UE, 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 a V2X policy provision process. The method of the UE performing the V2X policy provision process via a RAN node or a CN belonging to an NPN different from the NPN to which the UE belongs may be appropriately applied by using the method disclosed in the fourth modification of the first embodiment.

[0371] As another method, the CN may notify the RAN node of information on 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 information on 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 requesting 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 notify the NPN to which the UE belongs and the PC5 communication resources available in that NPN by including it in the V2X policy.

[0372] The UE may notify the AMF of information for identifying the UE, such as UE identifier information, and / or information for identifying the RAN node, such as RAN node identifier information, together with information requesting 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 the request, the PCF provides the V2X policy to the RAN node via the AMF. The method of providing the V2X policy from the PCF to the RAN node may be the method disclosed in the fourth modification of the first embodiment, as appropriate.

[0373] In this way, the RAN node can recognize the PC5 communication resources that can be used in the NPN to which the UE belongs. The RAN node broadcasts the PC5 communication resources that can be used in the NPN to which the UE belongs. The RAN node may broadcast information about the NPN to which the UE belongs and the PC5 communication resources that can be used in that NPN in association with each other. In this way, the UE can perform PC5 communication using the PC5 communication resources broadcast from a cell that belongs to an NPN different from the UE itself. It becomes possible to perform V2X services using PC5 communication.

[0374] Figures 24 and 25 are diagrams showing a first example of a sequence for performing PC5 communication via a cell that does not belong to the UE's own NPN, in accordance with the fifth modification of the first embodiment. Figures 24 and 25 are connected at boundary line BL2425. Figures 24 and 25 show an example in which a UE performs scheduling of PC5 communication. In Figures 24 and 25, steps that are common to Figures 18 to 20 and Figures 22 to 23 are assigned the same step numbers, and common explanations will be omitted.

[0375] In Step ST1629, the RAN node broadcasts PC5 communication related information. In Step ST1521, when a V2X service using PC5 communication occurs in the transmitting UE, in Step ST2040, the transmitting UE associates the V2X service with the PC5 communication RP for the V2X service and the NPN that can use the V2X service, by using the V2X communication related information received in Step ST1417 and the PC5 communication related information received in Step ST1629.

[0376] In step ST1638, the transmitting UE selects an RP corresponding to an NPN that can use the generated V2X service. The transmitting UE performs scheduling for PC5 communication using the selected RP. Through the processing of steps ST1642 to ST1746, the transmitting UE performs NPN accessibility verification. In this way, if the NPN cannot use the desired V2X service, PC5 communication can be made impossible. The transmitting UE can perform NPN accessibility verification.

[0377] Figures 26 and 27 are diagrams showing a second example of a sequence for performing PC5 communication via a cell that does not belong to the own NPN, in accordance with the fifth modification of the first embodiment. Figures 26 and 27 are connected at the position of boundary line BL2627. Figures 26 and 27 show an example in which the AMF performs NPN access permission verification for the UE. V2X communication related information notified to the UE from the AMF is included in a reject notification for NPN access. In Figures 26 and 27, steps common to Figures 18 to 19, 24, and 25 are assigned the same step numbers, and common explanations will be omitted.

[0378] In Step ST1905, the transmitting UE determines whether or not it can access a cell that does not belong to its own NPN. If the transmitting UE determines that it can access the cell, in Step ST1407, it accesses the RAN node and notifies the RAN node of the NPN-related information and V2X capability. In Step ST1408, the RAN node notifies the AMF of the NPN-related information and V2X capability received from the UE. The methods disclosed in Figs. 18 and 19 may be applied as appropriate to the method of notifying the NPN-related information and V2X capability.

[0379] In step ST2112, the AMF performs NPN access verification for the UE to the NW. The AMF performs NPN access verification using NPN-related information notified from the UE. Here, since the UE is accessing via a cell that does not belong to its own NPN, the AMF determines that the NPN cannot be accessed.

[0380] Furthermore, even if it is determined that the NPN accessibility verification does not allow access, the AMF requests the PCF to provide V2X communication-related information by using the V2X capability information notified from the UE. Through the processes of steps ST1413 to ST1415, the AMF acquires V2X-related information for the UE from the PCF.

[0381] The AMF refrains from notifying the RAN node and the UE of an NPN access denial until it acquires the V2X-related information. In steps ST2114 and ST2116, the AMF notifies the RAN node and the transmitting UE of the NPN access denial. The AMF includes the V2X-related information acquired in step ST1415 in the NPN access denial. In this way, the RAN node and the transmitting UE can acquire the V2X-related information.

[0382] In this way, by including V2X-related information in the NPN access denial and notifying it to the RAN node and UE, it is possible to utilize the NPN access control (NPN access permission verification) process in the conventional AMF. By reducing the additional process, it becomes possible to easily perform these processes.

[0383] The method disclosed in this Modification 5 of Embodiment 1 can achieve the same effects as those shown in Modification 4 of Embodiment 1. Furthermore, since the UE performing PC5 communication performs scheduling for PC5 communication and the RAN node does not need to perform scheduling for PC5 communication, there is no need for the UE to access the RAN node to request PC5 communication, etc. This makes it possible to start PC5 communication with low delay.

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

[0385] The QoS parameters or QoS rules may be included in the V2X-related information. The QoS parameters or QoS rules may be included in the V2X policy or V2X parameters. The CN side may provide the QoS parameters or QoS rules to the UE using the V2X-related information providing method or the V2X policy providing method disclosed in the first embodiment or its modification. This makes it possible to avoid different and complicated processing methods and reduce malfunctions.

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

[0387] PC5 communication is performed between UEs. Base stations do not perform PC5 communication. Even if the base station performs scheduling for PC5 communication with the UE, the base station does not perform PC5 communication. As a result, the base station cannot recognize the QoS of PC5 communication between UEs. For example, the base station cannot recognize whether the PC5 communication satisfies the requested QoS. Therefore, even if the communication quality of PC5 communication deteriorates and the requested QoS is no longer met, the base station cannot recognize this and will continue to perform the same scheduling as before. This will result in a situation where the requested QoS is not being met.

[0388] The second embodiment discloses a method for solving such a problem.

[0389] A UE performing PC5 communication monitors the QoS of the PC5 communication. The UE performing PC5 communication may be a transmitting UE or a receiving UE. The PC5 communication may be broadcast, groupcast, or unicast. The UE may measure QoS parameters as a QoS monitor. The QoS monitoring may be performed for all or some of the QoS parameters.

[0390] A UE that has performed QoS monitoring notifies the base station of the QoS monitoring results. The UE then notifies the base station of the measurement results of the QoS parameters it performed as a QoS monitor. For example, a transmitting UE performing PC5 communication measures the QoS parameters of the PC5 communication and notifies the base station that performs scheduling for the PC5 communication of the measurement results of the QoS parameters. In this way, the base station that performs scheduling for PC5 communication can recognize the actual QoS of the PC5 communication.

[0391] Specific examples of QoS parameters of PC5 to be measured are disclosed below as (1) to (11).

[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) Combination of (1) to (10).

[0403] A UE engaged in PC5 communication may measure some or all of these QoS parameters to monitor the QoS of the PC5 communication. The UE may measure these QoS parameters directly, or the UE may measure other indicators and use the results to derive these QoS parameters.

[0404] The range in (10) above indicates the minimum distance that must satisfy QoS. Therefore, UEs performing PC5 communication should derive the distance between UEs performing PC5 communication. This section discloses a method for UEs performing PC5 communication to derive the distance between UEs performing PC5 communication.

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

[0406] The transmitting UE derives the distance between UEs using the SL-RSRP of PC5 communication notified by the receiving UE. The transmitting UE is aware of the transmission power of the transmission signal of PC5 communication. The transmitting UE can derive the radio wave propagation loss between UEs using the transmission power and the SL-RSRP of PC5 communication obtained from the receiving UE, and derive the distance between UEs from the radio wave propagation loss. In this way, the transmitting UE can derive the distance between UEs performing PC5 communication.

[0407] Another method will be disclosed. A UE performing PC5 communication derives its own UE's position. The transmitting UE notifies the receiving UE of its own UE's position information. The receiving UE receives the position information from the transmitting UE and derives the distance between the UEs using the transmitting UE's position information and its own UE's position information. The receiving UE notifies the transmitting UE of the derived distance between the UEs. The UE may derive its position using GNSS or a RAN node. The RAN node may be, for example, a gNB in ​​NR or an eNB in ​​LTE. In this way, 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 derives the distance between the UEs using the location information of the receiving UE and its own UE. In this way, the transmitting UE can derive the distance between UEs performing PC5 communication.

[0409] The location information may be information indicating the area in which the UE is located. For example, the area may be divided into predetermined areas and each area may be assigned an identifier. The distance may be derived from the area identifier in which each UE is located. This reduces the amount of location information communicated between UEs.

[0410] Another method is disclosed. The receiving UE derives the radio wave propagation loss between UEs performing PC5 communication. The transmitting UE notifies the receiving UE of the transmission power of the transmission signal of PC5 communication. RRC signaling may be used for the notification. This is effective when the transmission power is changed semi-statically. Alternatively, MAC signaling may be used. This is effective when the transmission power is changed relatively quickly. 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 notified transmission power value may be the difference from the previous transmission power.

[0411] A receiving UE performing PC5 communication measures the received power of a signal transmitted from a corresponding transmitting UE. The receiving UE derives a radio wave propagation loss using the measured received power and the transmission power value notified by the transmitting UE. The receiving UE may notify the transmitting UE of the derived radio wave propagation loss. The transmitting UE may derive the distance between the UEs using the radio wave propagation loss notified by the receiving UE. In this way, 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. In this way, the transmitting UE can recognize the distance between the UEs performing PC5 communication.

[0413] The above-mentioned SL-RSRP, radio wave 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 wave propagation loss, or UE-to-UE distance.

[0414] As another method, a threshold for triggering notification may be set for SL-RSRP, radio wave propagation loss, or distance between UEs. For example, notification may be performed when a measured or derived value falls below or exceeds the threshold. The threshold and the conditions for performing notification may be statically determined in advance by a standard 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 multiple thresholds and conditions may be set. For example, since there are various PC5 communication states depending on the radio wave propagation environment, thresholds and conditions may be set according to these PC5 communication states.

[0415] The method of notifying the transmission power of the transmission signal in PC5 communication may be applied as the method of notifying the notification period, notification request, or threshold or condition. Similar effects can be obtained. RRC signaling may be used as a method for the receiving UE to notify the transmitting UE of SL-RSRP, radio wave propagation loss, or UE-to-UE distance. 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 wave propagation loss, or UE-to-UE distance may be notified as feedback information in the PSFCH. This is effective when notifying dynamically. The value to be notified may be the difference from the previous value.

[0416] In this way, UEs performing PC5 communication can derive the distance between UEs performing PC5 communication, and it becomes possible to derive the range, which is one index of the QoS parameters.

[0417] Another method is disclosed for a UE performing PC5 communication to derive the distance between UEs performing PC5 communication. The UE may derive the distance between the UEs from the radio wave propagation delay time of the PC5 communication between the UEs. An example of a method for deriving the radio wave propagation delay time of the PC5 communication between UEs is disclosed. A transmitting UE that derives the radio wave propagation delay time in PC5 communication may be referred to as UE_tx, and a receiving UE may be referred to as UE_rx.

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

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

[0420] Alternatively, the timing correction signal may be set in common within the transmitting UE in SL communication. By using the timing correction signal set in common within the UEs that are the transmission destination, the UE that is the transmission destination can identify that the timing correction signal was transmitted to its own UE.

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

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

[0423] SRS may be used as the timing correction signal. This eliminates the need to set up separate resources for the timing correction signal, improving resource usage efficiency.

[0424] The introduction of the Physical Sidelink Feedback Channel (PSFCH) has been proposed as a channel for transmitting Ack / Nack and CQI in SL communication. The frequency-time resources to which the PSFCH is mapped may be configured for each UE or each group. The PSFCH may also be used as a timing correction signal. This eliminates the need to configure a separate resource for the timing correction signal, thereby improving resource usage efficiency.

[0425] The PRACH in the Uu interface defined between the gNB and the UE may be used as the timing correction signal. A PRACH setting for PC5 may be provided separately from the PRACH setting for Uu and used as the timing correction signal. The gNB may notify the UE performing SL communication of the PRACH setting used for SL communication. This eliminates the need to provide a new timing correction signal. This simplifies the configuration for SL communication in the UE.

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

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

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

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

[0430] (4) UE_tx identifier.

[0431] (5) UE_rx identifier.

[0432] (6) A combination of (1) to (5).

[0433] It is preferable to use information for specifying the transmission timing as the above-mentioned (2). For example, a frame number, a slot number, a symbol number, etc. may be used as the above-mentioned (2). An offset value may also be included in these. Furthermore, the time difference from the timing of receiving a timing correction signal transmission request to the timing of transmitting the timing correction signal may also be used as the above-mentioned (2). As a unit of the offset value or time difference, a unit indicating the time resource to which the above-mentioned timing correction signal is mapped may be used. UE_rx can specify the timing of transmitting the timing correction signal.

[0434] The configuration of the timing correction signal in (3) above may be the above-mentioned sequence, the frequency-time resource to which the timing correction signal is mapped, etc. UE_rx can transmit the timing correction signal using the configuration of the received timing correction signal.

[0435] An identifier for identifying UE_tx may be used as the identifier of UE_tx in (4) above, which enables UE_rx to identify to which UE the timing correction signal is to be transmitted.

[0436] The identifier of UE_rx in (5) above may be an identifier for identifying UE_rx. The UE that has received the timing correction signal transmission request can determine whether or not to transmit the timing correction signal.

[0437] The timing correction signal transmission request may include multiple pieces of information. For example, multiple pieces of information (2) above may be notified, or multiple pieces of information (3) above may be notified. UE_rx may transmit multiple timing correction signals. Alternatively, UE_rx may select one or more pieces of information from the multiple 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 timing correction signal may have one or more 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] The configuration of the timing correction signal may be set by the UE_tx. The 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] The UE_tx notifies the UE_rx of the configured configuration of the timing correction signal (timing correction signal settings). The UE_rx transmits the timing correction signal using the timing correction signal settings notified by the UE_tx. The UE_rx may select one of the timing correction signal settings notified by the UE_tx and transmit the timing correction signal with the selected setting.

[0441] By having the UE_tx set the configuration of the timing correction signal, for example, even when SL communication between UEs is performed outside the coverage of the cell, the timing correction signal can be set for the UE_rx, which enables the UE_rx to transmit the timing correction signal.

[0442] The gNB may set the configuration of the timing correction signal. The 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. The gNB notifies the UE_tx of the set configuration of the timing correction signal (timing correction signal setting).

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

[0444] By having the gNB set the configuration of the timing correction signal, it becomes possible to set different timing correction signals for different UE_tx. This makes it possible to vary the configuration of the timing correction signal transmitted by the UE_rx, thereby reducing collisions of timing correction signals. This makes it possible to improve the probability that the UE_tx will successfully receive the timing correction signal from the UE_rx.

[0445] The configuration of the timing correction signal may be set by the UE_rx. Alternatively, the 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 having the UE_rx set the configuration of the timing correction signal, it is possible to reduce the signaling required for notifying the UE_rx of the timing correction signal configuration from the UE_tx, or the signaling required for notifying the UE_rx of the timing correction signal configuration from the gNB via the UE_tx, thereby reducing the amount of signaling and the delay time until the timing correction signal is transmitted.

[0447] A method for notifying a timing correction signal transmission request is disclosed. When UE_tx notifies UE_rx of a timing correction signal transmission request, PC5 control signaling in SL communication may be used. Alternatively, RRC signaling in SL communication may be used. UE_tx may notify the timing correction signal transmission request as an RRC message for SL communication using RRC signaling for SL communication. UE_tx may transmit the timing correction signal transmission request by including it in SCCH, which is a logical channel for SL. In this way, it becomes possible for UE_tx to notify UE_rx of a timing correction signal transmission request.

[0448] Another method for notifying the timing correction signal transmission request will be disclosed. UE_tx may notify UE_rx of the timing correction signal transmission request using MAC signaling in SL communication. UE_tx may notify the timing correction signal transmission request by including it in MAC control information. Since UE_rx does not need to perform RRC reception processing for the timing correction signal transmission request, it becomes possible to execute the reception processing earlier.

[0449] Another method for notifying a timing correction signal transmission request will be disclosed. UE_tx may include the timing correction signal transmission request in the SCI in SL communication and transmit it to UE_rx on the PSCCH in SL communication. UE_tx may include the timing correction signal transmission request in the above-mentioned SCI1. UE_tx may include the timing correction signal transmission request in SCI1 and notify it on PSCCH1. Alternatively, UE_tx may include the timing correction signal transmission request in SCI2. UE_tx may include the timing correction signal transmission request in SCI2 and notify it on PSCCH2. Notifying the timing correction signal transmission request on the PSCCH allows UE_rx to perform reception processing early. This makes it possible to set up timing correction signal transmission from UE_rx early.

[0450] Another method for notifying a timing correction signal transmission request will be disclosed. UE_tx may transmit the timing correction signal transmission request to UE_rx using the PSCCH and PSSCH in SL communication. For example, UE_tx may transmit information indicating the timing correction signal transmission request and an identifier of UE_rx included in the information included in the timing correction signal transmission request on the PSCCH by including the SCI, and may transmit other information on the PSCCH associated with the PSCCH. When the timing correction signal transmission request includes a large amount of information, it is possible to transmit the large amount of information using the PSSCH, which can secure a large amount of resources.

[0451] The above-mentioned methods of notifying the timing correction signal transmission request may be used in combination. For example, the UE_tx may transmit part of the information to be included in the timing correction signal transmission request by RRC signaling, and transmit the other information by including it in the PSCCH. For example, the UE_tx may transmit the configuration of the timing correction signal by RRC signaling, and transmit the other information by the PSCCH. In this way, for example, when configuring multiple timing correction signal configurations, it becomes possible to transmit a large amount of information by RRC signaling.

[0452] The UE_tx may notify the configurations of multiple timing correction signals separately from the configuration of one timing correction signal that the UE_rx will actually transmit from among those configurations. In such a case, the above-mentioned combination may also be used. For example, the UE_tx may notify the configurations of multiple timing correction signals by RRC signaling, and may notify the configuration of one timing correction signal that the UE_rx will actually transmit from those configurations by PSCCH together with timing correction signal transmission request information. Using RRC signaling makes it possible to transmit a large amount of information. Using the PSCCH makes it possible to perform processes from notifying the timing correction signal transmission request to transmitting the timing correction signal with low latency.

[0453] The configuration of the timing correction signal may be broadcast from the UE_tx as broadcast information in SL communication. For example, the UE_tx may include the configuration of the timing correction signal in the SL MIB and transmit it on the PSBCH. This eliminates the need for the UE_tx to individually notify multiple UE_rxes of the configuration of the timing correction signal. This can improve the efficiency of use of signaling resources. For example, this is effective when the configuration of the timing correction signal is set for each UE_tx.

[0454] The UE_rx transmits the timing correction signal at a predetermined timing. The UE_rx may use, as the predetermined timing, timing information for transmitting the timing correction signal received from the UE_tx. Alternatively, the UE_rx may transmit the timing correction signal at the predetermined timing by using frequency-time resources indicated in the configuration of the timing correction signal most recently received 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 a timing set by the UE_tx. The UE_rx transmits the timing correction signal using the configured configuration of the timing correction signal.

[0455] In this way, UE_tx can recognize the timing at which UE_rx transmits 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 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 an RTT for each UE_rx.

[0457] When the timing correction signal from UE_rx is transmitted via multiple paths, the signal received earliest by UE_tx may be used to derive the RTT, or the signal with the strongest reception power may be used to derive the RTT.

[0458] UE_tx derives the radio wave propagation delay time between UEs from the individual RTT of UE_rx. The radio wave propagation delay time should be half the RTT. UE_tx uses the derived radio wave propagation delay time to derive the distance between UEs. In this way, UE_tx can derive the distance between itself and UE_tx. UE_tx can measure the range between itself and UE_rx.

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

[0460] There may be multiple UE_rxs, and similar time synchronization correction processing may be performed individually for multiple UEs.

[0461] The UE_tx may notify the UE_rx of timing correction signal configuration candidates. The UE_rx selects the timing correction signal configuration to be used for actual transmission from the configuration candidates. This allows the UE_rx to transmit the timing correction signal using the timing correction signal configuration that can be transmitted at the earliest timing after receiving the timing correction signal transmission request. This allows timing correction to be performed with low delay.

[0462] The UE_tx may receive transmissions from the UE_rx using all timing correction signal configurations selected as candidates. The UE_tx can receive timing correction signals using any configuration transmitted by the UE_rx. The UE_rx may select multiple timing correction signal configurations to be used for actual transmission from among the timing correction signal configuration candidates. The UE_rx may transmit timing correction signals using the selected timing correction signal configurations. By transmitting using multiple timing correction signal configurations, the probability of successful reception of the timing correction signal at the UE_tx can be improved. For example, even if the UE_tx cannot receive one timing correction signal, it is sufficient if it can receive another timing correction signal.

[0463] The timing correction signal configuration candidates may be selected individually for each of a plurality of UEs to which information on time synchronization is transmitted from UE_tx. This makes it possible to avoid duplication of timing correction signal configurations between UEs. As another method, for example, timing correction signal configuration candidates may be selected so that some or all of the timing correction signal configuration candidates are common among a plurality of UEs. Although there is a possibility of duplication of timing correction signal configurations between UEs, this makes it possible to improve resource usage efficiency.

[0464] The UE_rx may retransmit the timing correction signal. The UE_rx determines whether or not to perform retransmission. If the UE_rx determines to perform retransmission, it selects another timing correction signal configuration from the timing correction signal configuration candidates and transmits the timing correction signal of the selected configuration to the UE_tx. The UE_tx may notify the UE_rx of retransmission timing information in advance. The UE_tx may set the retransmission timing for each timing correction signal configuration. The UE_rx may notify the retransmission timing information by including it in the notification of the timing correction signal configuration. In this way, for example, the UE_tx can have the UE_rx retransmit the timing correction signal without waiting for the next timing correction signal configuration.

[0465] A method for UE_rx to determine whether to retransmit a timing correction signal is disclosed. If UE_rx cannot receive time correction information within a predetermined time, UE_rx decides to retransmit the timing correction signal. Alternatively, if UE_rx cannot receive information related to time synchronization within a predetermined time, UE_rx may decide to retransmit the timing correction signal.

[0466] A timer may be provided to manage the predetermined time. The predetermined time may be statically determined in advance by a standard or the like, or may be set by the UE_tx and notified to the UE_rx. Alternatively, the predetermined time may be set by the gNB, notified from the gNB to the UE_tx, and notified from the UE_tx to the UE_rx. In this way, if the UE_tx fails to receive the timing correction signal, the UE_rx can decide to retransmit the timing correction signal. By having the UE_rx retransmit the timing correction signal, it is possible to improve the probability of successful reception at the UE_tx.

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

[0468] This allows UEs performing PC5 communication to derive the distance between other UEs performing PC5 communication. For example, when performing D2D communication in a shielded area in a factory, it becomes possible to measure the distance between devices without using signals from a base station or GPS.

[0469] Furthermore, for example, a UE carried by a pedestrian derives the distance between itself and a UE carried by a vehicle, and if the derived distance falls below a predetermined threshold, the pedestrian is notified. 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. In this way, the pedestrian can recognize that a vehicle has approached closer than the predetermined distance, and can take action to avoid contact with the vehicle.

[0470] The distance measurement results between UEs performing PC5 communication may be used to derive the position of the UE. The distance measurement results between multiple UEs may be used. For example, the radio wave propagation delay between UEs described above may be used as a method for deriving the position in the UE. Information on radio wave propagation delay between multiple UEs or distance information derived from the radio wave propagation delay is notified between the multiple UEs. The UE derives its own position using information on propagation delay between multiple other UEs. The derived position may be a relative position, for example, a relative position indicating the positional relationship between the UEs.

[0471] When measuring radio wave propagation delay information between multiple UEs, the measurement timing may be the same. Alternatively, the measurement timing may be within a predetermined time range. The measurement timing may be shared among multiple UEs in advance. For example, the measurement timing may be notified in advance between the multiple UEs that will be measuring. In this way, it is possible to keep the measurement timing of each UE within a predetermined range. This improves the accuracy of measuring the relative positions of multiple UEs.

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

[0473] Distance measurements between UEs can be used to derive the location of devices in shielded areas, for example in a factory, or when there is no signal from a base station or GPS, for example in a tunnel.

[0474] The distance measurement results between the gNB and the UE may also be used. By combining the distance measurement results with the distance measurement results between UEs, the accuracy of UE location measurement can be improved.

[0475] The measurement or derivation of QoS parameters may be performed in the V2X application layer. The QoS parameters derived in 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 in the V2X layer. The QoS parameters derived in the V2X layer may be notified to the AS layer. The measurement or derivation of QoS parameters may be performed in a different layer for each QoS parameter. Measurement or derivation can be performed in an appropriate layer depending on the QoS parameter content.

[0476] The UE that has performed QoS monitoring notifies the base station of the QoS monitoring results. As a method of notification from the UE to the base station, communication on Uu may be used. RRC signaling may also 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. In this way, the UE that has performed QoS monitoring can notify the base station of the QoS monitoring results. The base station can obtain the QoS monitoring results of PC5 communication from the UE that performs PC5 communication.

[0477] The base station can use the QoS monitoring results of PC5 communication to determine whether the PC5 communication satisfies the required QoS. The base station can use the QoS monitoring results of PC5 communication to change the scheduling for PC5 communication as necessary. After changing the scheduling for PC5 communication, the base station notifies the UE performing PC5 communication of the changed scheduling information.

[0478] It has been disclosed that the number of QoS parameters to be measured may be one or more, and may be a combination of the specific examples of the QoS parameters described above. All QoS parameters that the UE notifies the base station may be notified by 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 depending on the measurement timing. For example, the RAN node may periodically set the timing for notifying the UE of the QoS monitoring result, and may notify the QoS parameters measured between the previous QoS monitoring result notification timing and the next QoS monitoring result notification timing in the same signaling.

[0480] The RAN node may reschedule using the QoS monitoring results in each signaling notified from the UE, thereby enabling the QoS monitoring results to be reflected in scheduling at an early stage.

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

[0482] For example, this is effective when a UE performing PC5 communication has acquired required QoS parameters. The UE performing PC5 communication sets the required value of each QoS parameter as a threshold, and notifies the RAN node of whether the QoS monitoring result is equal to or greater than the threshold. The predetermined value or threshold of the QoS parameter may be different from the required QoS parameter value. Flexible setting is possible according to the communication quality and communication environment of the SL.

[0483] In this way, it is possible to reduce the amount of information of the QoS monitoring results that a UE performing PC5 communication notifies to a RAN node.

[0484] Figures 28 and 29 are diagrams showing an example of a sequence for performing QoS monitoring of PC5 communication according to the second embodiment. Figures 28 and 29 are connected at the position of boundary line BL2829. Figures 28 and 29 show the operations of the UE, RAN node, AMF, SMF, UPF, and PCF. This section discloses a method in which a transmitting UE performing PC5 communication performs QoS monitoring of PC5 communication. In Step ST2202, the transmitting UE performing PC5 communication notifies the RAN node (for example, a base station) of its V2X capability. The UE may also notify the RAN node of its PC5 communication capability. In Step ST2203, the RAN node notifies the AMF of the V2X capability received from the UE.

[0485] The UE may signal the V2X capability, for example, through NAS signaling. For example, the UE may signal the V2X capability by including it in a message for a registration process. For example, the UE may signal the V2X capability by including it in a message for a service request process.

[0486] For example, RRC signaling may be used between the UE and the RAN node to notify the V2X capability. When RRC signaling is used, the V2X capability may be notified, for example, during an RRC connection establishment procedure.

[0487] For example, NG signaling may be used between the RAN node and the AMF to signal the V2X capability. The NG signaling may be N2 signaling.

[0488] The AMF recognizes that it is possible to provide V2X services using the V2X capability received from the UE. The AMF recognizes that it is possible to provide V2X services for PC5 communication using the PC5 communication capability. The UE may notify V2X service provision request information along with the V2X capability. The AMF can recognize that the UE is clearly requesting the provision of V2X services.

[0489] In Step ST2204, the AMF notifies the PCF of the V2X capability received from the UE. For this notification, for example, the AMF may use the Npcf interface or a UE Policy Control Create Request message.

[0490] The UE may notify the PCF of a V2X policy provision request. The UE may notify the PCF by including the request in a UE Policy Container to be notified. The UE may notify the PCF of the request via the AMF. The notification from the UE to the AMF may be made, for example, using NAS signaling. For example, a UE Policy Provision Request message may be used. The notification from the AMF to the PCF may be made, for example, using the Npcf interface or a UE Policy Control Update message.

[0491] In Step ST2205, the PCF that has received the information from the UE performs V2X service authentication using the registration data of the UE. The PCF also decides to provide a V2X policy to the UE. The PCF also decides to provide a V2X service and corresponding QoS-related information to the UE. The V2X policy may include V2X parameters. The V2X policy may include a V2X service and 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 V2X communication-related information. The PCF notifies the AMF of V2X service and corresponding QoS-related information as the V2X communication-related information. The V2X communication-related information may include a V2X policy. The V2X policy may include a V2X service and corresponding QoS-related information. For example, QoS parameters for each V2X service may be included as the V2X parameters. The PCF may notify the AMF of the V2X communication-related information by using a UE policy provision procedure. For example, the Namf interface may be used, or a Communication N1N2 MessageTransfer message may be used.

[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 the notification. In this way, the RAN node can acquire V2X-related information for the UE. The RAN node can acquire QoS-related information corresponding to the V2X service. By the RAN node acquiring 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. In this way, the UE can also acquire the V2X communication related information. The UE can acquire the QoS related information corresponding to the V2X service.

[0495] Although it has been shown that V2X communication-related information and QoS-related information are notified using the same signaling, they may be notified using different signaling. By using separate signaling, for example, if there are no updates to V2X-related information other than QoS-related information, it is possible to notify only QoS-related information through signaling. This makes it possible to reduce signaling capacity.

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

[0497] In Step ST2214, the RAN node notifies the transmitting UE of the scheduling information for PC5 communication. The transmitting UE performs PC5-S signaling with the receiving UE using the scheduling information for PC5 communication received from the RAN node in Step ST2214, and establishes 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 broadcast the request. The receiving UE, which has received the PC5 communication request for the V2X service, notifies the transmitting UE of PC5 communication accept in Step ST2217.

[0498] After the PC5-S link is established, in Step ST2218, the transmitting UE performs RRC signaling with the receiving UE to mutually notify each other of, for example, AS layer configuration information, UE capability information, etc. In this way, both the transmitting UE and the receiving UE can configure 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. In this way, the PC5 communication performed between the transmitting UE and the receiving UE can be performed so as to satisfy the QoS required for the PC5 communication.

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

[0501] Some 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 different. Different QoS-related information settings may be used. It is possible to differentiate the QoS for each signaling and data transmission. For example, the RAN node may schedule PC5 communication to satisfy the QoS required for each signaling or data communication. For example, the QoS for signaling may be set to a QoS parameter with lower latency or higher quality than that for data transmission. This can reduce malfunctions caused by incorrect transmission and reception of signaling.

[0502] Predetermined QoS-related information may be determined in advance for the QoS for PC5-S signaling and / or the QoS for RRC signaling. The information may be determined in advance by standards, etc. This makes it possible to reduce signaling for notifying QoS-related information.

[0503] In Step ST2220, the UE performing PC5 communication performs QoS monitoring of the PC5 communication. As a QoS monitor, the UE measures QoS transmission-related parameters. Here, the case where the UE performing QoS monitoring is a transmitting UE is shown.

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

[0505] For example, if the communication quality of the PC5 communication between the transmitting UE and the receiving UE deteriorates and the QoS-related parameter measurement result does not satisfy the requested QoS, the RAN node may perform scheduling to satisfy the requested QoS, for example, by increasing the resources allocated for the PC5 communication. For example, if the communication quality of the PC5 communication between the transmitting UE and the receiving UE improves and the QoS-related parameter measurement result greatly exceeds the requested QoS, the RAN node may perform scheduling to reduce the excess resources while satisfying the requested QoS, for example, by reducing the resources allocated for the PC5 communication.

[0506] In this way, the RAN node performs scheduling for PC5 communication using the QoS-related parameter measurement results from the transmitting UE, making it possible to efficiently perform scheduling that satisfies 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. In Step ST2233, the transmitting UE uses the PC5 communication scheduling information to transmit and receive V2X service data to and from the receiving UE. While the transmission and reception of V2X service data has been disclosed here, the same applies to the transmission and reception of PC5-S signaling and PC5 RRC signaling.

[0508] In this way, the RAN node performs scheduling using the QoS-related parameter measurement results from the transmitting UE, thereby enabling PC5 communication between the transmitting UE and the receiving UE to satisfy the QoS required for the PC5 communication.

[0509] Although the QoS monitoring is performed by the transmitting UE, it may alternatively be performed by the receiving UE. The receiving UE may perform the QoS monitoring and notify the transmitting UE of the measurement results of the QoS-related parameters. The transmitting UE may also notify the RAN node of the measurement results of the QoS-related parameters, which are the QoS monitoring results of the receiving UE.

[0510] There are cases where the communication quality of PC5 communication differs between the receiving UE and the transmitting UE. For example, this may occur when there is another UE that causes interference near the receiving UE. This may occur when the other UE interferes with the receiving UE but not with the transmitting UE. In such cases, the quality of communication from the transmitting UE to the receiving UE deteriorates. By acquiring the QoS-related parameter measurement results from the receiving UE, the RAN node can recognize such situations and can schedule PC5 communication appropriately.

[0511] Both QoS monitoring in the receiving UE and QoS monitoring in the transmitting UE may be performed. The RAN node may acquire both QoS-related parameter measurement results. By using both QoS-related parameter measurement results, the RAN node can perform scheduling to satisfy the QoS required for PC5 communication.

[0512] The method disclosed in the second embodiment makes it possible to avoid a situation in which the QoS required for V2X services using PC5 communication between UEs continues to be unsatisfied.

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

[0514] The above method may be applied when the frequency or frequency band used for UL Uu communication is the same as the frequency or frequency band used for PC5 communication. 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 between a base station and a UE performing PC5 communication is generally the same as the communication quality of PC5 communication between UEs performing PC5 communication. Therefore, the QoS monitoring results for UL Uu communication are generally the same as the QoS monitoring results for PC5 communication between UEs.

[0515] A base station that has performed QoS monitoring of UL Uu communication between a UE performing PC5 communication and the base station can use the QoS monitoring results to determine whether the UE satisfies the required QoS. Furthermore, the base station can change the scheduling for PC5 communication as necessary based on the determination results. The base station that has changed the scheduling for PC5 communication may notify the UE performing PC5 communication of the changed scheduling information.

[0516] This eliminates the need for QoS monitoring in UEs performing PC5 communication. It also eliminates the need for UEs performing PC5 communication to notify the base station of QoS monitoring results. This makes it possible to facilitate QoS monitoring control and scheduling for PC5 communication using QoS monitoring results as a system.

[0517] Variation 1 of Embodiment 2 In this first modification, another method for solving the problem disclosed in the second embodiment will be disclosed.

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

[0519] The one or more QoS parameter sets or QoS parameter set lists may be included in the V2X-related information. The one or more QoS parameter sets or QoS parameter set lists may be included in the V2X policy or V2X parameters. The method for providing V2X-related information or the method for providing V2X policy disclosed in the first embodiment or its modification may be applied to the method by which the CN side provides the UE with the one or more QoS parameter sets or QoS parameter set lists. This makes it possible to avoid different and complicated processing methods and reduce malfunctions.

[0520] The QoS parameters, QoS parameter sets, or QoS parameter set lists may be stored in the CN-side node. A V2X service using PC5 communication may be stored in the CN-side node in association with the QoS parameters, QoS parameter sets, or QoS parameter set lists required for the service. The storage method may be the method disclosed in the first embodiment, as appropriate. This information can be used as needed.

[0521] The UE that performed the QoS monitoring notifies the QoS monitoring result to a node that has multiple QoS parameter sets for the V2X service. For example, if the PCF has multiple QoS parameter sets, the UE may notify the QoS monitoring result to the PCF. The UE may also notify the QoS monitoring result to the PCF via the RAN node or the AMF.

[0522] The node that receives the QoS monitoring result from the UE may reselect a QoS parameter set for the V2X service from among the multiple QoS parameter sets that have been set, in accordance with the QoS monitoring result.

[0523] The PCF may notify the base station that performs scheduling for PC5 communication of the reselected QoS parameter set. The base station receives the reselected QoS parameter set from the PCF. The base station may use the QoS parameters to reschedule PC5 communication for the UE that performs PC5 communication. The PCF may notify the base station of the reselected QoS parameter set via the AMF.

[0524] In this way, it is possible to reselect a QoS parameter set using the QoS monitoring results for PC5 communication, and to re-perform scheduling for PC5 communication using the reselected QoS parameter set. This makes it possible to perform scheduling for PC5 communication that matches the communication quality of PC5 communication. It is also possible to improve the efficiency of resource usage for PC5 communication.

[0525] It has been disclosed that the UE that performed QoS monitoring notifies the PCF of the QoS monitoring result. As an alternative method, the UE that performed QoS monitoring may notify the base station of the QoS monitoring result, and the base station may notify the PCF of the QoS monitoring result by the UE. The PCF reselects a QoS parameter set from among multiple configured QoS parameter sets according to the QoS monitoring result, and notifies the base station of the reselected QoS parameter set. In this way, the base station can request the CN to reselect a QoS parameter set at its own discretion.

[0526] For example, the base station can use the QoS monitoring results received from the UE performing PC5 communication to determine whether to change the scheduling for PC5 communication without changing the QoS parameter set, or to request a change in the QoS parameter set. In this way, the base station can appropriately determine the use of signaling to the CN according to the QoS monitoring results, thereby reducing the amount of signaling with the CN.

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

[0528] The method disclosed in the second embodiment may be applied as appropriate to the method by which a UE that has performed QoS monitoring notifies a RAN node of the QoS monitoring result. The RAN node may notify an AMF of the QoS monitoring result. N2 signaling may be used for notification between the RAN node and the AMF. The method described above may be applied to the method by which an AMF notifies a PCF.

[0529] 30 to 32 are diagrams showing an example of a sequence for performing QoS monitoring of PC5 communication in accordance with Modification 1 of Embodiment 2. FIGS. 30 to 32 are connected at the positions of borders BL3031 and BL3132. In the example of FIGS. 30 to 32, the measurement results of QoS-related parameters for PC5 communication are notified up to the CN. In FIGS. 30 to 32, steps common to FIGS. 28 and 29 are assigned the same step numbers, and common explanations will be omitted.

[0530] A plurality of QoS parameters for a V2X service using PC5 communication are configured. As described above, a QoS parameter consists of one or a plurality of types of parameters. Therefore, a QoS parameter may also be referred to as a QoS parameter set. In Step ST2301, the PCF has a plurality of QoS parameter set configurations for a V2X service using PC5 communication. Following V2X communication access authentication using PC5 communication from the transmitting UE, in Step ST2306, the PCF selects one from the plurality of configurations of QoS parameter sets 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. The PCF may provide information indicating that multiple QoS parameter sets are configured for PC5 communication and notify the AMF and / or the RAN node and / or the UE. The AMF and / or the RAN node and / or the UE will be able to recognize that multiple QoS parameter sets are configured for PC5 communication.

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

[0533] In Step ST2220, the transmitting UE performs QoS monitoring. The transmitting UE measures QoS-related parameters and, in Step ST2221, notifies the RAN node of the measurement results. In Step ST2322, the RAN node notifies the AMF of the QoS-related parameter measurement results notified by the transmitting UE. In Step ST2323, the AMF notifies the PCF of the QoS-related parameters notified by the RAN node. The notification method may be the above-mentioned method in which the transmitting UE notifies the PCF of V2X capabilities or V2X policy requests. A separate message may be provided for notification.

[0534] In Step ST2324, the PCF that has received the QoS-related parameter measurement results for PC5 communication from the UE appropriately selects one of the multiple QoS parameter sets for PC5 communication that have been set. The PCF may select a QoS parameter set for PC5 communication that is different from the QoS parameter set for PC5 communication that was previously selected.

[0535] For example, if the communication quality of PC5 communication between a transmitting UE and a receiving UE deteriorates and the measurement results of QoS-related parameters do not satisfy the requested QoS, the PCF selects, for example, from the configured QoS parameter sets for PC5 communication, a QoS parameter set for PC5 communication that satisfies the QoS.For example, if the communication quality of PC5 communication between a transmitting UE and a receiving UE improves and the measurement results of QoS-related parameters greatly exceed the requested QoS, the PCF selects, for example, from the configured QoS parameter sets for PC5 communication, a QoS parameter set for PC5 communication that is appropriate for the measured QoS.

[0536] In this way, the PCF can provide the RAN node with a QoS parameter set for PC5 communication that is suitable for the communication quality of PC5 communication, which enables the RAN node to perform scheduling for PC5 communication that is 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 the QoS parameter set for PC5 communication reselected by the PCF as the V2X communication-related information. 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. In this way, the RAN node can acquire the QoS parameter set for PC5 communication reselected for the UE. The RAN node can acquire QoS-related information for PC5 communication appropriate for the QoS monitoring result of PC5 communication. By the RAN node acquiring the V2X-related information of the QoS parameter set for PC5 communication reselected for the UE, the RAN node can perform scheduling for a V2X service using PC5 communication appropriate 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 reselected QoS parameter set for PC5 communication. In this way, the UE can also acquire the reselected QoS parameter set for PC5 communication.

[0539] In Step ST2331, the RAN node performs scheduling for PC5 communication using the reselected QoS parameter set for PC5 communication acquired 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. In Step ST2233, the transmitting UE uses the PC5 communication scheduling information to transmit and receive V2X service data to and from the receiving UE. While transmission and reception of V2X service data has been disclosed here, the same applies to 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 of the multiple configured QoS parameter sets for PC5 communication and provides the selected QoS parameter set to the RAN node again. This enables the RAN node to perform scheduling for PC5 communication in accordance with the communication quality of PC5 communication. It also enables efficient scheduling of resources used for PC5 communication. It also makes it possible to improve the efficiency of resource usage for PC5 communication.

[0541] The method of notifying one or more QoS parameter sets or QoS parameter set lists from the PCF to the base station may use the method of providing V2X-related information or the V2X policy provision process disclosed in the first embodiment or its modification.

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

[0543] In this way, by the AMF obtaining the QoS parameter set in advance, it is possible to reduce the signaling between the AMF and 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 change the QoS parameters. The UE notifies the SMF of the QoS monitoring result. The UE may 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 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] The method disclosed in this first modification of the second embodiment makes it possible to avoid a situation in which the QoS required for V2X services using PC5 communication between UEs is not met for a long period of time.

[0546] Variation 2 of Embodiment 2 A UE performing PC5 communication may perform scheduling for PC5 communication. In such a case, resources used for PC5 communication scheduling are selected from a resource pool. The resource pool may be broadcast from a base station. This disclosure will discuss a method for solving the problem disclosed in the second embodiment when a UE performing PC5 communication performs scheduling for PC5 communication using a resource pool broadcast from a base station.

[0547] Multiple resource pools are configured for use in V2X services using PC5 communication. Multiple resource pools are configured for V2X services using PC5 communication. 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 PCC (Policy and Charging Control). Hereinafter, the configured multiple resource pools may be referred to as a resource pool list.

[0548] One or more resource pools or resource pool lists may be configured along with QoS parameters for the V2X service. Rules may be configured for deriving a resource pool from a service request for a V2X service using PC5 communication. A rule for deriving QoS parameters from a service request for a V2X service using PC5 communication and a rule for deriving a resource pool from the request may be configured in the same rule.

[0549] One or more resource pools or resource pool lists used in a V2X service using PC5 communication may be included in the V2X-related information. One or more resource pools or resource pool lists used in a V2X service using PC5 communication may be included in the V2X-related information together with QoS parameters for the V2X service. The method of providing these and the method of storing them in the CN-side node may be the method disclosed in the second embodiment or the first modification of the second embodiment, as appropriate. Similar effects can be obtained.

[0550] The UE that performed the QoS monitoring notifies the node that has multiple resource pools for the V2X service of the QoS monitoring result. For example, if the PCF has multiple resource pools, the UE may notify the PCF of the QoS monitoring result. The node that receives the QoS monitoring result from the UE may reselect a resource pool for the V2X service from the multiple configured resource pools according to the QoS monitoring result.

[0551] The PCF may notify the base station that broadcasts the resource pool for PC5 communication of the reselected resource pool. The PCF may also notify the base station that notified 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 broadcasts the resource pool. The UE performing PC5 communication may re-perform PC5 communication scheduling using the reselected resource pool from the base station. The PCF may also notify the base station of the reselected resource pool via the AMF.

[0552] In this way, the method of setting multiple resource pools and changing the resource pool based on the QoS monitoring result may be appropriately applied to the method disclosed in the first modification of the second embodiment. In the method disclosed in the first modification of the second embodiment, the QoS parameter set may be replaced with a resource pool. Also, the scheduling for PC5 communication performed by the base station for UEs performing PC5 communication may be replaced with notification of the resource pool for PC5 communication.

[0553] In this way, it is possible to reselect the resource pool to be used for PC5 communication using the QoS monitoring results for PC5 communication, and to re-execute scheduling for PC5 communication using the reselected resource pool. This makes it possible to execute scheduling for PC5 communication that matches the communication quality of PC5 communication. This makes it possible to improve the resource usage efficiency for PC5 communication.

[0554] Priorities may be set for QoS parameter sets. Priorities may also be set for resource pools. QoS parameter sets and resource pools may be reselected according to the priorities. For example, selection or reselection may be performed from QoS parameter sets or resource pools with high priorities. Setting priorities in this way makes it possible to control the QoS parameter sets and resource pools to be used.

[0555] For example, the above-described QoS parameter set and resource pool reselection method may be combined with the priority level. For example, when the measurement results of QoS-related parameters do not satisfy the requested QoS, a QoS parameter set for PC5 communication that satisfies the QoS is selected from the configured QoS parameter sets for PC5 communication. When there are multiple QoS parameter sets for PC5 communication to choose from, a QoS parameter set with a high priority is selected from among them. 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 requested QoS, a QoS parameter set for PC5 communication that is suitable for the measured QoS is selected from the configured QoS parameter sets for PC5 communication. When there are multiple QoS parameter sets for PC5 communication to choose from, a QoS parameter set with a high priority is selected from among them.

[0556] In this way, PC5 communication can be performed with a desired QoS, and the efficiency of use of resources used for PC5 communication can be improved.

[0557] Ranks may be provided. One or more QoS parameter sets or resource pools may be set for each rank. Depending on the QoS monitoring results, it is advisable to reselect a QoS parameter set or resource pool within the selected rank. This allows for greater flexibility in reselection than control based on 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, location, and communication environment of each UE. As another method, the priority and rank may be set for each V2X service using PC5 communication. The priority and rank can be set according to the content and requirements of the service.

[0559] The method disclosed in this variant example 2 of embodiment 2 makes it possible to avoid a situation where the QoS required for V2X services using PC5 communication between UEs is not met for a long period of time, even when a UE performing PC5 communication performs scheduling for PC5 communication using a resource pool notified by a base station.

[0560] Variation 3 of Embodiment 2 A UE performing PC5 communication may perform scheduling for PC5 communication. In such a case, a QoS parameter set corresponding to the V2X service used for PC5 communication scheduling is configured in advance in the UE. This disclosure will discuss a method for solving the problem disclosed in the second embodiment when a UE performing PC5 communication performs scheduling for PC5 communication using a QoS parameter set configured in advance in the UE.

[0561] When a UE performing PC5 communication enters the coverage of a base station, the QoS parameter set is changed via the base station. The QoS parameter set may be changed using a V2X policy update process between a UE performing PC5 communication and a PCF. The method of performing QoS monitoring may be the method disclosed in the second embodiment. The method of providing V2X-related information or the method of providing a V2X policy disclosed in the first embodiment or its modification may be applied to the method of setting multiple QoS parameter sets for PC5 communication and the method of changing the QoS parameter set using a V2X policy update process between a UE and a PCF. This makes it possible to avoid different and complicated processing methods and reduce malfunctions.

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

[0563] When a UE performing PC5 communication enters the coverage of a base station, the resource pool is changed via the base station. The resource pool may be changed using a V2X policy update process between a UE performing PC5 communication and a PCF. The method of performing QoS monitoring may be the method disclosed in the second embodiment. The method of providing V2X-related information or the method of providing a V2X policy disclosed in the first embodiment or its modification may be applied to the method of setting multiple resource pools for PC5 communication and the method of changing a resource pool using a V2X policy update process between a UE and a PCF. This makes it possible to avoid different and complicated processing methods and reduce malfunctions.

[0564] The above-mentioned QoS parameter set change and resource pool change may both 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 it. The PCF acting as the CN side node may also determine it. The CN side node may determine it using the QoS monitoring result notified from the UE.

[0565] A UE performing PC5 communication may reschedule for PC5 communication using the changed QoS parameter set and / or resource pool. In this way, when a UE performing PC5 communication enters the coverage of a base station, the QoS parameter set can be changed via the base station. For example, even if a UE is performing PC5 communication outside of coverage and the QoS for V2X services is no longer satisfied, the UE can change the QoS parameter set via the base station when it enters the coverage of the base station. This makes it possible to avoid a situation where the QoS for V2X services is not satisfied for a long period of time.

[0566] Another method is disclosed. The UE acquires in advance multiple QoS parameter sets and / or multiple resource pools for V2X services. The UE performing PC5 communication acquires in advance the QoS parameter set list and / or resource pool list from a CN-side node having the QoS parameter set list and / or resource pool list. The CN-side node having the QoS parameter set list and / or resource pool list provides in advance the QoS parameter set list and / or resource pool list to the UE performing PC5 communication.

[0567] The process of providing a QoS parameter set list and / or a resource pool list between a UE and a CN-side node having a QoS parameter set list and / or a resource pool list may be performed by appropriately applying the above-described method.

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

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

[0570] Multiple 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 multiple QoS parameter sets for PC5 communication. The PCF may notify the UE of multiple QoS parameter sets for PC5 communication by including them in QoS-related information. In this way, the UE can acquire multiple QoS parameter sets for PC5 communication.

[0572] In Step ST2413, the UE selects one of the multiple QoS parameter sets for PC5 communication acquired in Step ST2409, and performs scheduling for PC5 communication using the selected QoS parameter set.

[0573] In Step ST2220, the transmitting UE performs QoS monitoring. The transmitting UE measures QoS-related parameters. In Step ST2425, the transmitting UE appropriately reselects one of the multiple configured QoS parameter sets for PC5 communication, using the QoS-related parameter measurement results. The transmitting UE may select a QoS parameter set for PC5 communication that is different from the QoS parameter set for PC5 communication that was previously selected.

[0574] For example, if the communication quality of PC5 communication between the transmitting UE and the receiving UE deteriorates and the QoS-related parameter measurement results do not satisfy the requested QoS, the transmitting UE selects, for example, from the configured QoS parameter sets for PC5 communication, a QoS parameter set for PC5 communication that satisfies the QoS.For example, if the communication quality of PC5 communication between the transmitting UE and the receiving UE improves and the QoS-related parameter measurement results greatly exceed the requested QoS, the transmitting UE selects, for example, from the configured QoS parameter sets for PC5 communication, a QoS parameter set for PC5 communication that is appropriate for the measured QoS.

[0575] In Step ST2431, the transmitting UE performs scheduling for PC5 communication using the reselected QoS parameter set for PC5 communication. In this way, the PCF notifies the transmitting UE of multiple QoS parameter sets for PC5 communication, which enables the transmitting UE to re-perform scheduling for PC5 communication in accordance with the communication quality of PC5 communication using the QoS monitoring results. This makes it possible to efficiently schedule resources used for PC5 communication. This makes it possible to improve the efficiency of resource usage for PC5 communication.

[0576] As described above, multiple QoS parameter sets and / or multiple resources for a V2X service using PC5 communication may be configured or stored in a CN-side node. For example, PCF and PCC have been disclosed as CN-side nodes. However, the CN-side node is not limited to these, and may also be AMF, SMF, or UPF. Multiple QoS parameter sets and multiple resources for a V2X service using PC5 communication may be configured or stored in different CN-side nodes.

[0577] A UE performing PC5 communication performs QoS monitoring and notifies the CN-side node of the QoS monitoring results. The CN-side node reselects a QoS parameter set and / or resources using the QoS monitoring results from the UE. The CN-side 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.

[0578] By configuring or storing multiple QoS parameter sets and / or multiple resources for V2X services using PC5 communication in the CN-side node, for example, AMF, SMF, or UPF, it is possible to reduce the access time from the UE to the CN-side node. The UE can quickly perform scheduling for PC5 communication using the reselected QoS parameter sets and / or resources. This makes it possible to reduce the period during which the QoS required for V2X services using PC5 communication is not satisfied.

[0579] In the above description, it has been disclosed that multiple QoS parameter sets and / or multiple resources for V2X services using PC5 communication are configured or stored in the CN side node. In contrast, multiple QoS parameter sets and / or multiple resources for V2X services using PC5 communication may be configured or stored in the RAN node. A UE performing PC5 communication performs QoS monitoring and notifies the RAN node of the QoS monitoring results. The RAN node reselects the QoS parameter set and / or resources using the QoS monitoring results from the UE. The RAN node notifies the UE of the reselected QoS parameter set and / or resources. The UE performs scheduling for PC5 communication using the notified QoS parameter set and / or resources.

[0580] By doing so, it is possible to further shorten the period during which the QoS required for V2X services using PC5 communication is not satisfied.

[0581] Figures 35 and 36 are diagrams showing a second example of a sequence for performing QoS monitoring of PC5 communication according to the third modification of the second embodiment. Figures 35 and 36 are connected at the position of boundary line BL3536. Figures 35 and 36 show an example in which a RAN node broadcasts resources for PC5 communication. Figures 35 and 36 show an example in which a UE performs scheduling for PC5 communication. In Figures 35 and 36, steps that are common to Figures 30 to 32 and Figures 33 to 34 are assigned the same step numbers, and common explanations will be omitted.

[0582] Multiple QoS parameters for V2X services using PC5 communication are notified from the PCF to the RAN node.

[0583] In steps ST2407 and ST2408, the PCF notifies the RAN node of multiple QoS parameter sets for PC5 communication. The PCF may notify the multiple QoS parameter sets for PC5 communication by including them in QoS-related information. In this way, the RAN node can acquire multiple QoS parameter sets for PC5 communication.

[0584] In Step ST2613, the RAN node selects one of the multiple QoS parameter sets for PC5 communication acquired in Step ST2408. The RAN node configures resources for PC5 communication using the selected QoS parameter set, and in Step ST2615, broadcasts the resources for PC5 communication to the UE. The RAN node may broadcast the resources for PC5 communication by including them in PC5-related information. The resources for PC5 communication may be resource pool information.

[0585] In Step ST2617, the transmitting UE performs scheduling for PC5 communication using the PC5 communication-related information.

[0586] In Step ST2220, the transmitting UE performs QoS monitoring. The transmitting UE performs QoS-related parameter measurement. 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 of the multiple configured QoS parameter sets for PC5 communication, using the QoS-related parameter measurement results notified from the transmitting UE. The RAN node may select a QoS parameter set for PC5 communication that is different from the QoS parameter set for PC5 communication that was previously selected.

[0587] The method for selecting QoS parameters for PC5 communication may be the method disclosed above for the case where the PCF or the UE selects QoS parameters for PC5 communication. The RAN node configures resources for PC5 communication using the QoS parameter set for PC5 communication reselected in Step ST2626. In this way, the RAN node can configure resources for PC5 communication that are suitable for the QoS of PC5 communication.

[0588] In Step ST2628, the transmitting UE receives the reset PC5 communication related information and acquires the RP for PC5 communication. In Step ST2630, the transmitting UE performs scheduling for PC5 communication using the reset PC5 communication related information. In this way, the PCF notifies the RAN node of multiple QoS parameter sets for PC5 communication, and the RAN node configures PC5 communication resources suitable for the selected QoS parameter set for PC5 communication and broadcasts the configured PC5 communication resources. This enables the transmitting UE to perform scheduling for PC5 communication using the reset PC5 communication resources.

[0589] Therefore, it is possible to reschedule the PC5 communication so as to match the communication quality of the PC5 communication. It is possible to efficiently schedule the resources used for the PC5 communication. It is possible to improve the efficiency of resource use for the PC5 communication.

[0590] The method in which the PCF notifies the RAN node of multiple QoS parameter sets for PC5 communication can also be applied when the RAN node performs scheduling for PC5 communication, thereby making it possible to improve resource usage efficiency for PC5 communication.

[0591] It has been disclosed that multiple QoS parameter sets and / or multiple resources for V2X services using PC5 communication are configured or stored in a CN-side node or a RAN node. As another example, a node having multiple QoS parameter sets and / or multiple resources for V2X services using PC5 communication may provide these in advance to another node, such as a CN-side node or a RAN node. The multiple QoS parameter sets and / or multiple resources may be provided in response to a request from the other node. By providing these in advance to the other node, a similar effect can be achieved.

[0592] Another method is disclosed. Multiple QoS parameter sets and / or multiple resource pools for the V2X service may be configured in the UE in advance. The multiple QoS parameter sets and / or multiple resource pools for the V2X service may be stored in the UE. The multiple QoS parameter sets and / or multiple resource pools for the V2X service may be stored in the UE in advance, rather than being provided by a provisioning process between the UE and the PCF. For example, the multiple QoS parameter sets and / or multiple resource pools for the V2X service may be stored in the (U)SIM or CICC.

[0593] A UE performing PC5 communication performs QoS monitoring and changes a QoS parameter set and / or a resource pool using the QoS monitoring result. The QoS parameter set and / or resource pool to be changed is selected from a QoS parameter set list and / or a resource pool list preconfigured in the UE. The UE performing PC5 communication performs scheduling for PC5 communication using the reselected QoS parameter set and / or resource pool.

[0594] Figure 37 is a diagram showing a third example of a sequence for performing QoS monitoring for PC5 communication in accordance with Modification 3 of Embodiment 2. Figure 37 shows an example in which a transmitting UE performs scheduling for PC5 communication. In Figure 37, steps that are common to Figures 33 to 34 are assigned the same step numbers, and common explanations will be omitted.

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

[0596] In Step ST2510, multiple QoS parameter sets for PC5 communication are configured in the transmitting UE. In Step ST2512, the transmitting UE selects one from the multiple QoS parameter sets for PC5 communication configured in the UE. In Step ST2513, the transmitting UE performs scheduling for PC5 communication using the selected QoS parameter set.

[0597] In Step ST2220, the transmitting UE performs QoS monitoring. The transmitting UE measures QoS-related parameters. In Step ST2530, the transmitting UE appropriately reselects one of the configured QoS parameter sets for PC5 communication, using the QoS-related parameter measurement results. The transmitting UE may select a QoS parameter set for PC5 communication that is different from the QoS parameter set for PC5 communication that was previously selected.

[0598] The method for selecting QoS parameters for PC5 communication may be the method described above. In step ST2531, the transmitting UE performs scheduling for PC5 communication using the reselected QoS-related information for PC5 communication. In this way, the transmitting UE can re-perform scheduling for PC5 communication in accordance with the communication quality of PC5 communication. It becomes possible to efficiently schedule resources used for PC5 communication. It becomes possible to improve the efficiency of resource usage for PC5 communication.

[0599] In this way, even if the UE is performing PC5 communication outside the coverage area and the QoS for the V2X service is no longer satisfied, the UE can change the QoS parameter set, which makes it possible to avoid a situation in which the QoS for the V2X service is not satisfied for a long time.

[0600] A UE performing PC5 communication may be a UE that relays PC5 communication and PC5 communication, or a UE that relays Uu communication and PC5 communication. A QoS parameter set and / or multiple resource pools may be provided to these UEs. When the UE performs relaying, it can reschedule the PC5 communication based on the QoS monitoring result.

[0601] An example has been disclosed in which a UE performing PC5 communication performs QoS monitoring and notifies a RAN node or a CN node of the QoS monitoring result. Instead of the QoS monitoring result, information indicating whether or not the QoS value is satisfied may be provided. A UE performing PC5 communication may perform QoS monitoring and notify a RAN node or a CN node of information indicating whether or not the QoS value is satisfied. By applying the above-mentioned method appropriately, a similar effect can be obtained.

[0602] Alternatively, the UE performing PC5 communication may notify the RAN node of a rescheduling request. The request may be a rescheduling request for QoS improvement. The UE performing PC5 communication performs QoS monitoring and uses the QoS monitoring result to determine whether to notify the RAN node of a rescheduling request.

[0603] For example, if the QoS monitoring result does not satisfy the QoS required for the V2X service using PC5 communication, or satisfies but falls within a predetermined range, the UE determines to notify a rescheduling request. Otherwise, the UE determines not to notify a rescheduling request.

[0604] When a UE performing PC5 communication decides to notify a rescheduling request, the UE notifies the RAN node of the rescheduling request. The RAN node that receives the request performs rescheduling so as to improve the QoS for the UE, and notifies the UE of the rescheduling request.

[0605] By doing so, it is possible to improve the QoS of V2X services using PC5 communications.

[0606] The rescheduling request may be a rescheduling request for QoS relaxation. For example, if a UE performing PC5 communication determines that the QoS monitoring result significantly exceeds the required QoS, the RAN node may notify the RAN node of a rescheduling request for QoS relaxation. The RAN node receiving the request performs rescheduling so as to relax the QoS for the UE, and notifies the UE of the information.

[0607] By doing this, it becomes possible to relax the QoS of V2X services using PC5 communication. By relaxing the QoS to the extent that the QoS is satisfied, it becomes possible to allocate resources to other UEs. This makes it possible to improve the resource usage efficiency of the system.

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

[0609] For example, if the QoS monitoring result does not satisfy the QoS required for the V2X service using PC5 communication, or satisfies but falls within a predetermined range, the UE determines to notify a re-provision request. Otherwise, the UE determines not to notify a re-provision request.

[0610] When a UE performing PC5 communication decides to notify a re-provisioning request, the UE notifies the NW node of the re-provisioning request. The NW node that receives the request, for example, reselects a QoS parameter set and / or a resource pool so as to improve the QoS for the UE, and re-provides information of the reselected QoS parameter set and / or resource pool to the UE.

[0611] By doing so, it is possible to improve the QoS of V2X services using PC5 communications.

[0612] The re-provision request may be a re-provision request for QoS relaxation. For example, if a UE performing PC5 communication determines that the QoS monitoring result significantly exceeds the required QoS, the CN node may notify the CN node of a re-provision request for QoS relaxation. The CN node receiving the request reselects a QoS parameter set and / or a resource pool so as to relax the QoS for the UE, and re-provisions information of the reselected QoS parameter set and / or resource pool to the UE.

[0613] By doing this, it becomes possible to relax the QoS of V2X services using PC5 communication. By relaxing the QoS to the extent that the QoS is satisfied, it becomes possible to allocate resources to other UEs. This makes it possible to improve the resource usage efficiency of the system.

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

[0615] When there are no more QoS parameter sets and / or resource pools to reselect, PC5 communication may be terminated. The node that performs the reselection may initiate the release of PC5 communication. AS layer resources may be released as the release of PC5 communication. When the release of PC5 communication is initiated, the transmitting UE may release its own UE resources and notify the receiving UE of a request to release the AS layer resources. Upon receiving the release request, the receiving UE releases the AS layer resources. The receiving UE may notify the transmitting UE of the completion of the release of the AS layer resources. The transmitting UE may release its own UE resources upon receiving the notification.

[0616] RRC signaling may be used for notification of resource release initiation for PC5 communication, notification of resource release request, and notification of resource release completion. This makes it possible to reduce erroneous reception of the notification and notify a large amount of information. As another method, MAC signaling may be used. This makes it possible to notify earlier while reducing erroneous reception of the notification. As another method, PHY signaling may be used. This makes it possible to notify earlier. These notification methods may be varied depending on the content of the notification. It is possible to obtain the above-mentioned effects depending on the content of the notification.

[0617] The release of the PC5-S link may be performed as the release of PC5 communication. The release of the PC5-S link may be performed together with the release of AS layer resources. When the release of PC5 communication is initiated, the transmitting UE may release its own PC5-S link and notify the receiving UE of a PC5-S link release request. The release process of the PC5-S link releases settings in the V2X layer, such as settings such as mapping between application identifiers from the application layer in the V2X service and identifiers used in L2.

[0618] Upon receiving the release request, the receiving UE releases 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 release its own PC5-S link upon receiving the notification.

[0619] By doing so, even when there are no QoS parameter sets and / or resource pools to reselect, it is possible to reduce unnecessary processing, such as a UE performing PC5 communication continuing to hold resources for PC5 communication. This makes it possible to improve the efficiency of radio resource usage. Furthermore, it is possible to reduce unnecessary processing in the UE, thereby reducing the power consumption of the UE.

[0620] Variation 4 of Embodiment 2 3GPP is considering groupcast as a method of PC5 communication. Groupcast is a method of PC5 communication between UE groups. A UE group is set up with a leader UE (leader UE) and other UEs (member UEs), and PC5 communication is performed between the leader UE and member UEs or between member UEs. For PC5 communication between leader UE and member UEs, it is advisable to apply the above-mentioned method, and similar effects can be obtained.

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

[0622] For example, if the quality of PC5 communication between member UEs deteriorates and the required QoS is no longer met, the leader UE that schedules PC5 communication between member UEs will not recognize the quality deterioration of PC5 communication and will continue to perform the same scheduling. As a result, the QoS required for PC5 communication between member UEs will continue to be not met.

[0623] In this fourth modification, a method for solving such problems will be disclosed.

[0624] The leader UE may perform a V2X policy providing process for the CN. The leader UE can acquire V2X communication related information from the CN. As a method for this, the method disclosed in the third modification of the second embodiment may be applied. The PCF may provide multiple QoS parameter sets to the UE, or may provide one QoS parameter set. The leader UE performs scheduling for PC5 communication between member UEs using the V2X policy provided by the CN.

[0625] The V2X policy for PC5 communication between member UEs in a group may be the same as that for communication between the leader UE and the sending member UE. By using the same V2X policy for PC5 communication within a group, the PC5 communication processing within the group can be simplified, and PC5 communication between members can be performed with low latency.

[0626] The V2X policy for PC5 communication between member UEs in a group may be different from that for communication between a leader UE and a sending member UE. The sending member UE may perform authentication of the V2X service using PC5 communication and / or a V2X policy provision process for the PCF via the leader UE. The leader UE performs a V2X policy provision process for the sending member UE to the PCF via the RAN node and the AMF. The V2X policy provision process between the leader UE and the PCF may be performed using the method disclosed in the third modification of the second embodiment.

[0627] The leader UE may have established a PC5 communication link with the member UEs in the group in advance. The sending member UE may request the leader UE to authenticate the V2X service using PC5 communication and / or provide a V2X policy. The sending member UE can initiate the request for authentication of the V2X service using PC5 communication and / or provide a V2X policy via the leader UE.

[0628] Resources for PC5 communication between UEs in a group may be set in advance. The settings may be statically determined by a standard or the like. Alternatively, the settings may be configured in advance in the UEs in the group. The UEs in the group may perform PC5 communication using the resources until the V2X policy provision process is performed. The leader UE performs scheduling for PC5 communication between member UEs using the resources. For example, even when a member UE is outside the coverage of a cell, it is possible to use the V2X policy for PC5 communication.

[0629] In this way, UEs in the group, including member UEs, can use the V2X policy for PC5 communication. PC5 communication becomes possible within the group, for example, between a leader UE and member UEs, or between member UEs.

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

[0631] A member UE that has performed QoS monitoring notifies the leader UE of the QoS monitoring results. The UE then notifies the leader UE of the measurement results of the QoS parameters it has performed as a QoS monitor. In this way, the leader UE that schedules PC5 communication between member UEs can recognize the actual QoS of the PC5 communication.

[0632] The leader UE can use the QoS monitoring results of the PC5 communication between member UEs notified by the member UEs to determine whether the PC5 communication between member UEs satisfies the requested QoS. The leader UE can change the scheduling for the PC5 communication between member UEs as needed using the QoS monitoring results of the PC5 communication between member UEs. The leader UE notifies the member UEs of the changed scheduling information for the PC5 communication between member UEs.

[0633] These methods may be appropriately applied to the methods disclosed in the above-described embodiments or modifications. For example, the base station in the second embodiment may be replaced with a leader UE, and the UE performing PC5 communication may be replaced with a member UE performing PC5 communication. In this way, it is possible to obtain a desired QoS for a V2X service using PC5 communication between member UEs.

[0634] Fig. 38 is a diagram showing an example of a sequence for performing QoS monitoring of PC5 communication in accordance with Modification 4 of Embodiment 2. Fig. 38 shows an example in which groupcast communication is performed using PC5 communication. Fig. 38 shows an example in which a leader UE in a group performs scheduling for PC5 communication between member UEs. Fig. 38 shows the leader UE in the group, and sending member UEs and receiving member UEs that perform PC5 communication.

[0635] In Step ST2701, the leader UE performs scheduling for PC5 communication between the leader UE and the transmitting UE using QoS-related information. In Steps ST2702 to ST2704, a PC5 link is established between the leader UE and the transmitting member UE, and PC5 RRC signaling is performed. 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 include a BSR in the scheduling request.

[0636] In Step ST2706, the leader UE performs scheduling for inter-member PC5 communication by 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 sending member UE of the scheduling information for inter-member PC5 communication.

[0637] When the transmitting member UE receives the scheduling information for inter-member PC5 communication in Step ST2707, it notifies the receiving member UE of a PC5 communication request using the scheduling information in Step ST2708. The processes of Steps ST2708 to ST2711 may be the same as those of Steps ST2216 to ST2219 in Fig. 31 as appropriate. As a result, transmission and reception of V2X service data is carried out between the receiving member UE and the transmitting member UE.

[0638] In Step ST2712, the transmitting member UE performs QoS monitoring. The transmitting member UE measures QoS-related parameters and, in Step ST2713, notifies the leader UE of the measurement results. In Step ST2714, the leader UE performs scheduling for inter-member PC5 communication again, using the QoS-related parameter measurement results notified from the transmitting member UE. The scheduling method for inter-member PC5 communication using the QoS-related parameter measurement results may be the method disclosed in the second embodiment.

[0639] In Step ST2715, the leader UE notifies the transmitting member UE of the result information of the PC5 communication scheduling performed in Step ST2714. In Step ST2716, the transmitting member UE uses the PC5 communication scheduling information to transmit and receive V2X service data to and from the receiving member UE. While the transmission and reception of V2X service data has been disclosed here, the same applies to the transmission and reception of PC5-S signaling and PC5 RRC signaling.

[0640] In this way, the sending member UE monitors the QoS and notifies the leader UE of the QoS monitoring results, so that the leader UE can use the QoS monitoring results of the member-to-member PC5 communication to schedule the member-to-member PC5 communication. Therefore, even if the communication quality of the member-to-member PC5 communication changes, the QoS required for the member-to-member PC5 communication can be met.

[0641] A plurality of QoS parameter sets for PC5 communication may be configured in advance in the leader UE. The leader UE may select one of the plurality of QoS parameter sets for PC5 communication configured in advance in the UE, and perform PC5 communication scheduling using the selected QoS parameter set for PC5 communication. The method for selecting QoS parameters for PC5 communication may be the method described above. These methods may be appropriately applied to the method disclosed in the third modification of the second embodiment.

[0642] In this way, the transmitting UE can reschedule the PC5 communication so as to match the communication quality of the PC5 communication. This allows efficient scheduling of resources used for the PC5 communication. This allows for improved resource usage efficiency for the PC5 communication.

[0643] The case where the leader UE schedules PC5 communication between member UEs has been disclosed. The base station may also schedule PC5 communication between member UEs. When the leader UE is within the coverage of the base station, the base station may also schedule PC5 communication between member UEs. The scheduling information may be notified to the member UEs via the leader UE. The member UE uses the notified scheduling information to perform PC5 communication between member UEs.

[0644] The member UE may notify the base station of the QoS monitoring result of PC5 communication between member UEs. This may also be applied to cases where the base station performs scheduling of PC5 communication between member UEs. The leader UE may notify the base station of the QoS monitoring result of PC5 communication between member UEs acquired from member UEs. The base station uses the QoS monitoring result to change the scheduling for PC5 communication between member UEs. The base station notifies the leader UE of information about the changed scheduling for PC5 communication between member UEs. The leader UE notifies the member UE that performs PC5 communication of the scheduling information. The member UE performs PC5 communication between members using the received scheduling information.

[0645] The methods disclosed in the above-described embodiments or modifications may be applied as appropriate to these methods. The same effects can be obtained in PC5 communication between member UEs.

[0646] Multiple sets of QoS parameters required for V2X services using inter-member PC5 communication may be set. Multiple sets of QoS parameters required for V2X services using inter-group PC5 communication may be set, instead of the QoS parameters required for V2X services using inter-member PC5 communica...

Claims

1. A communication terminal device in a communication system, the communication system includes a plurality of communication terminal devices that perform unicast communication via a PC5 interface, and a base station device that communicates with the plurality of communication terminal devices; the communication terminal device releases the unicast communication with another communication terminal device among the plurality of communication terminal devices. Communications terminal equipment.

2. the communication terminal device performs the release based on a notification received from the other communication terminal device. The communication terminal device according to claim 1 .

3. The notification is included in an RRC (Radio Resource Control) message. The communication terminal device according to claim 2.

4. the communication terminal device transmits a notification of completion of the release to the other communication terminal device. The communication terminal device according to claim 2.

5. the communication terminal device transmits, to the other communication terminal device, a notification for the other communication terminal device to perform the release based on the notification received from the base station device; The communication terminal device according to claim 1 .

6. the communication terminal device performs the release based on a notification received from the base station device. The communication terminal device according to claim 1 .

7. The notification is included in an RRC (Radio Resource Control) message.

7. The communication terminal device according to claim 6.

8. the communication terminal device transmits a notification of completion of the release to the base station device in response to the notification received from the base station device.

7. The communication terminal device according to claim 6.

9. The communication terminal device performs AS (Access Stratum) layer resources in the release. The communication terminal device according to claim 1 .

10. A base station device in a communication system, the communication system includes a plurality of communication terminal devices that perform unicast communication via a PC5 interface, and the base station device that communicates with the plurality of communication terminal devices; the base station device transmits, to a communication terminal device among the plurality of communication terminal devices, a notification to release the unicast communication between the communication terminal device and another communication terminal device among the plurality of communication terminal devices. Base station equipment.

11. A base station device that communicates with a plurality of communication terminal devices that perform unicast communication via a PC5 interface, a communication terminal device among the plurality of communication terminal devices releases the unicast communication with another communication terminal device among the plurality of communication terminal devices; Communication system.

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