WO2022172819A1 - Relay terminal, core network device, and communication method - Google Patents

Abstract

Provided is a relay terminal comprising: a first transmission unit for transmitting a QoS request to a network device if the QoS request has been received from a first terminal; a reception unit for receiving information indicating rejection of the QoS request from the network device; a control unit for selecting a second terminal from among one or more terminals that communicate with the relay terminal if the information has been received; and a second transmission unit for transmitting, to the network device, a message requesting modification of a QoS request of the second terminal.

Description

Relay terminal, core network device and communication method Cross-reference to related applications

This application is based on Japanese Patent Application No. 2021-021253 filed on February 12, 2021, and claims the benefit of priority thereof. incorporated herein by reference.

The present disclosure relates to relay terminals, core network devices, and communication methods.

In the Third Generation Partnership Project (3GPP), an international standardization organization, Long Term Evolution (LTE), which is the 3.9th generation Radio Access Technology (RAT), and LTE-Advanced, which is the 4th generation RAT. As a successor, Release 15 of New Radio (NR), which is a fifth generation (5G) RAT, has been specified (for example, Non-Patent Document 1).
In addition, Release 15 of 5G Core Network (5GC), which is the 5th generation CN, has been specified as a successor to Evolved Packet Core (EPC), which is the 4th generation Core Network (CN) (for example, , Non-Patent Document 2).

　Currently, inter-device communication called Proximity based Services (ProSe) is being considered. Proximity services being considered for 5G are also called 5G ProSe. In addition, in 5G ProSe, research is also underway for relay communication, in which a remote terminal (Remote UE) communicates with a network via a relay terminal (Relay UE).

Here, the 5G network supports various types of communication, such as best-effort communication such as the Internet, communication that requires low latency, and communication that requires high reliability. It is possible to communicate by specifying QoS (Quality of Service).

Therefore, even when the remote terminal communicates with the 5G network via the relay terminal, it is conceivable that the remote terminal specifies QoS corresponding to the desired communication quality and performs communication.

Normally, if the network resources are not sufficient and the QoS requested by the remote terminal cannot be satisfied, the remote terminal's QoS request will be rejected. However, if the remote terminal is a terminal that performs high-priority communication, it is considered unfavorable to reject the QoS request.

An object of the present disclosure is to provide a relay terminal, a core network device, and a communication method that make it possible to meet the QoS requirements of terminals even when network resources are insufficient.

A relay terminal according to an aspect of the present disclosure includes a first transmitting unit that transmits the QoS request to a network device when receiving a QoS request from a first terminal, and rejecting the QoS request from the network device. a receiving unit for receiving information indicating the above; a control unit for selecting a second terminal from among one or more terminals communicating with the relay terminal when the information is received; and changing the QoS request of the second terminal and a second sending unit for sending a message to the network device requesting to do so.

According to the present disclosure, it is possible to provide a relay terminal, a core network device, and a communication method that make it possible to satisfy QoS requirements of terminals even when network resources are insufficient.

FIG. 1 is a diagram showing an example of an outline of a communication system according to this embodiment. FIG. 2 is a diagram for explaining problems in terminals and inter-network relays; FIG. 3 is a sequence diagram showing an example of a processing procedure (pattern 1) when notifying a QoS state; FIG. 4 is a sequence diagram showing an example of a processing procedure (pattern 2) when notifying a QoS state; FIG. 5 is a sequence diagram showing an example of a processing procedure (pattern 3) when notifying a QoS state; FIG. 6 is a sequence diagram showing an example of a processing procedure (pattern 1) in QoS control based on priority; FIG. 7 is a sequence diagram showing an example of a processing procedure (pattern 2) in QoS control based on priority; FIG. 8 is a sequence diagram showing an example of a processing procedure (pattern 3) in QoS control based on priority; FIG. 9 is a sequence diagram showing an example of a processing procedure (pattern 4) in QoS control based on priority; FIG. 10 is a diagram showing an example of the hardware configuration of each device in the communication system according to the embodiment; FIG. 11 is a diagram illustrating a functional block configuration example of a relay terminal; FIG. 12 is a diagram illustrating a functional block configuration example of a base station; FIG. 13 is a diagram showing a functional block configuration example of an AMF; FIG. 14 is a diagram showing a functional block configuration example of an SMF;

An embodiment of the present disclosure will be described with reference to the accompanying drawings. In addition, in each figure, the thing which attached|subjected the same code|symbol may have the same or the same structure.

<System configuration>
FIG. 1 is a diagram showing an example of an outline of a communication system according to this embodiment. As shown in FIG. 1, the communication system 1 includes a relay terminal (relay terminal) 10A, a remote terminal 10B, a base station 20, a core network 30, and a Data Network (DN) 40. Note that the numbers of terminals 10, base stations 20, and nodes in the core network 30 shown in FIG. 1 are merely examples, and are not limited to the numbers shown. In the following description, when not distinguishing between the relay terminal (Relay UE) 10A and the remote terminal (Remote UE) 10B, they are described as "terminal 10".

The terminal 10 is, for example, a predetermined terminal or device such as a smartphone, a personal computer, an in-vehicle terminal, an in-vehicle device, a stationary device, a telematics control unit (TCU), or the like. Terminal 10 may also be called a User Equipment (UE), a Mobile Station (MS), a User Terminal, a Radio apparatus, a subscriber terminal, an access terminal, and so on. The terminal 10 may be mobile or stationary.

The terminal 10 is configured to be able to communicate using, for example, LTE, LTE-Advanced, NR, etc. as a radio access technology (RAT) RAT for the base station 20, but not limited to this, the sixth generation It may be configured to be communicable using the subsequent RATs. In addition, the terminal 10 is not limited to the access network defined by 3GPP as described above (3GPP access network). may access.

The base station 20 forms one or more cells C and communicates with the terminal 10 using the cell C. The interface between terminal 10 and base station 20 is called Uu. Base station 20 includes gNodeB (gNB), en-gNB, radio access network (RAN), access network (AN), next generation radio access network (Next Generation-Radio Access Network: NG-RAN ) node, low-power node, Central Unit (CU), Distributed Unit (DU), gNB-DU, Remote Radio Head (RRH), integrated access and back It may also be called a hole (Integrated Access and Backhaul/Backhauling: IAB) node or the like. The base station 20 is not limited to one node, and may be composed of a plurality of nodes (for example, a combination of a lower node such as DU and an upper node such as CU).

The core network 30 is, for example, 5GC, but is not limited to this, and may be an EPC, a sixth generation or later core network, or the like. The core network 30 includes, for example, Access and Mobility Management Function (AMF) 31, Session Management Function (SMF) 32, User Plane Function (UPF) 33, Policy and Control Function (PCF) 34, Application Function (AF) 35, etc. include.

The AMF 31 is a mobility management device that manages the mobility of the terminal 10 . The AMF 31 is connected to the base station 20 via the N2 interface and to the terminal 10 via the N1 interface. The AMF 31 performs processing related to the control plane (for example, registration management, connection management, mobility management) and the like. The AMF 31 also performs processing related to non-access stratum (NAS), and transmits and/or receives NAS messages to and from the terminal 10 .

The SMF 32 is a session management device that manages sessions, for example, selects the UPF 33 used by the terminal 10 to communicate with the DN 40, and establishes, updates, and updates a PDU (Protocol Data Unit) session between the terminal 10 and the DN 40. Control release, etc. The SMF 32 is connected to the AMF 31 via the N11 interface and to the UPF 33 via the N4 interface.

The UPF 33 is a connection point to the DN 40 and performs, for example, packet routing and forwarding. The UPF 33 is connected to the SMF 32 via the N4 interface and to the base station 20 via the N3 interface. The UPF 33 performs packet routing and transfer according to the PDU session indicating the connection relationship between the terminal 10 and the DN 40 .

The PCF 34 is a policy management control device that manages and controls policies. For example, it determines QoS to be applied to traffic based on a predetermined policy. The RCF 34 is connected to the SMF 32 via the N7 interface and to the AF 35 via the N5 interface.

The AF 35 is a device that provides the core network 30 with necessary information when providing services (such as ProSe). AF 35 is connected to PCF 34 via the N5 interface.

The DN 40 is, for example, the Internet, a corporate network, an IP Multimedia Subsystem (IMS), or the like.

The functions included in the core network 30 are not limited to those shown in FIG. Also, the names of the functions and interfaces shown in FIG. 1 are merely examples, and are not limited to those shown in FIG. 1, and other names may be used as long as they have equivalent or similar functions. Also, a plurality of core network functions shown in FIG. 1 may be provided in a single device, or one core network function shown in FIG. 1 may be configured by a plurality of devices. A device that constitutes part or all of each function of the core network 30 is also called a “core network device”.

Downlink data from the DN 40 is transmitted from the UPF 33 to the base station 20 via the N3 tunnel, and transmitted from the base station 20 to the terminal 10 via the radio bearer. On the other hand, uplink data from the terminal 10 is transmitted from the terminal 10 to the base station 20 via the radio bearer, transmitted from the base station 20 to the UPF 33 via the N3 tunnel, and transmitted from the UPF 33 to the DN 40 . Note that the N3 tunnel is a tunnel for transmitting encapsulated IP (Encapsulated Internet Protocol) packets, and may be called a user plane tunnel or the like.

(QoS control)
QoS control in 5G is performed in units of one or multiple QoS flows (QoS Flows) defined within a PDU session. A QoS flow is uniquely identified using a QoS Flow ID (QFI). Each QoS flow is defined by a QoS profile, a QoS rule, and a UL/DL PDR (Uplink/Downlink Packet Detection Rule).

A QoS profile is information notified to the base station 20 from the SMF 32 via the AMF 31 . The base station 20 maps QoS flows to data radio bearers (DRBs) and schedules the data radio bearers based on the QoS characteristics specified by the QoS profile. The QoS profile includes QoS parameters such as 5G QoS Identifier (5QI), Allocation and Retention Priority (ARP), Reflective QoS Attribute (ROA) and Notification control. 5QI is an indicator that identifies the QoS characteristics predefined by the 3GPP specifications. QoS characteristics in 5G include, for example, resource type (guaranteed bit rate (GBR), non-guaranteed bit rate (Non-GBR), delay critical GBR), guaranteed flow bit rate (GFBR), maximum flow bit rate Rate (Maximum Flow Bit Rate: MFBR), priority level, packet delay budget, packet error rate, etc. are included. The notification control is information indicating whether or not to request the base station 20 to notify the core network 30 when GFBR in the QoS flow cannot be guaranteed or can be guaranteed again.

A QoS rule is information notified to the terminal 10 from the SMF 32 via the AMF 31 . The terminal 10 maps UL data to QoS flows based on QoS rules. QoS rules include QFI, packet filter sets, and the like.

The PDR is information notified from the SMF 32 to the UPF 33. Based on the PDR, the UPF 33 classifies the DL data received from the DN 40 and marks the QoS flow (appends QFI to the encapsulation header).

The QoS flow (QoS Flow) is managed by the SMF32. QoS flow setting/modification is performed by a PDU Session Establishment procedure or a PDU Session Modification procedure. That is, the QoS rule, QoS profile and PDR are notified to the terminal 10, base station 20 and UPF 33 by the PDU session establishment procedure or PDU session change procedure, respectively. Also, one PDU session can be associated with one or more QoS flows.

(relay between terminals and networks)
Currently, in 3GPP, as a specification of proximity service (ProSe) using terminal-to-terminal communication, a remote terminal 10B communicates with a network (base station 20 and core network 30) via a relay terminal 10A. (UE-to-Network Relay) is being studied. The remote terminal 10B may be called a Remote UE or a ProSe UE-to-Network Relay. Also, the relay terminal 10A and the remote terminal 10B support terminal-to-terminal communication (D2D communication, Sidelink communication).

The interface between the remote terminal 10B and the relay terminal 10A is called PC5.

The relay terminal 10A and the remote terminal 10B have the same functions, and it may be possible to arbitrarily switch between operating as the relay terminal 10A and operating as the remote terminal 10B. Alternatively, the relay terminal 10A and the remote terminal 10B may be terminals 10 having different functions. Also, the relay terminal 10A and the remote terminal 10B may have a function of operating as a normal terminal 10. FIG.

In addition, in 3GPP, as relays between terminals and networks, Layer 3 UE-to-Network Relay and Layer 2 UE-to-Network Relay in which the remote terminal 10B terminates the NAS layer. Relay) is being considered.

In layer 3 relay, the relay terminal 10A terminates the NAS (Non Access Stratum) layer, and the relay terminal 10A establishes a PDU session used for communication with the remote terminal 10B.

When end-to-end QoS is implemented in Layer 3 relay, the QoS flow for inter-terminal communication, ``PC5 QoS flow'', is applied to QoS control between relay terminal 10A and remote terminal 10B. You can do it. In the PC5 QoS flow, PQIs (PC5 5QIs) may be used as identifiers indicating QoS characteristics. Also, a PFI (PC5 QoS Flow Identifier) may be used as an identifier that uniquely identifies a PC5 QoS flow. For the QoS control between the remote terminal 10B and the DN 40, the QoS flow described in the above "QoS control" may be applied. In the following description, the QoS flow described in the above "QoS control" is referred to as "Uu QoS flow" for convenience in order to distinguish it from the PC5 QoS flow.

In layer 3 relay, in order to realize end-to-end QoS, the relay terminal 10A maps the PQI of the "PC5 QoS flow" and the 5QI of the "Uu QoS flow" between the PQI and the 5QI. Mutual conversion is performed based on the information (hereinafter referred to as "mapping table"). Thereby, end-to-end QoS control between the remote terminal 10B and the DN 40 can be realized.

Layer 2 relay is a form in which the remote terminal 10B terminates the NAS layer and the remote terminal 10B itself establishes a PDU session applied to the communication of the remote terminal 10B.

In the case of layer 2 relay, there is no PC5 QoS flow and the Uu QoS flow is applied between remote terminal 10B and DN40. Therefore, the relay terminal 10A may perform QoS control of the radio bearer on the PC5 link according to the QoS profile used for QoS control of the radio bearer on the Uu link.

(Issues of terminals and inter-network relays)
FIG. 2 is a diagram for explaining problems in terminals and inter-network relays.

At step S11, for example, many remote terminals 10B-1 to 10B-n (n is an arbitrary positive integer) are connected to the network via the relay terminal 10A and are communicating.

In step S12, a connection is established with the network via the relay terminal 10A in order for the new remote terminal 10B-X to start communication. At this time, a default QoS (QoS with non-guaranteed bit rate) is assigned as the QoS.

At step S13, the remote terminal 10B-X notifies the relay terminal 10A of the desired QoS. Here, it is assumed that the QoS desired by the remote terminal 10B-X (desired QoS condition) is a QoS with stricter conditions than the default QoS, such as a guaranteed bit rate.

In step S14, the relay terminal 10A notifies the network of the QoS desired by the remote terminal 10B-X. Since the relay terminal 10A and the network are already in a state where many remote terminals 10B-1 to 10B-n are communicating via the relay terminal 10A, it is impossible to accept the QoS request desired by the remote terminal 10B-X. recognize that you cannot. In step S15, the relay terminal 10A notifies the remote terminal 10B-X that it refuses to accept the QoS request desired by the remote terminal 10B-X.

In step S16, when the request for the desired QoS is rejected, the remote terminal 10B-X gives up communication via the relay terminal 10A and attempts communication via another relay terminal 10A.

Thus, if the QoS request is rejected, there is a problem that the processing procedure of steps S12 to S15 performed by the remote terminal 10B-X is wasted (first problem).

Further, if the remote terminal 10B-X is a terminal 10 that performs important communication with high priority such as mission-critical communication, it is considered undesirable to refuse to accept the QoS desired by the remote terminal 10B-X. (Second problem).

In FIG. 2, many remote terminals 10B-1 to 10B-n are connected to the network via the relay terminal 10A and are communicating, but the present invention is not limited to this. For example, even when the radio quality between the relay terminal 10A and the base station 20 is poor, or when the traffic of the core network 30 is tight, similar problems may arise.

In this embodiment, in order to solve the first problem, the relay terminal 10A determines whether or not the network can accept a QoS request with stricter requirements. (hereinafter referred to as "QoS state information") is notified to terminals 10 existing in the vicinity.

In addition, in order to solve the second problem, in the present embodiment, among the remote terminals 10B-1 to 10B-n already connected, the QoS of the remote terminal 10B, which has a lower priority than the remote terminal 10B-X, is increased. Change to QoS with looser requirements (hereinafter referred to as “priority-based QoS control”). As a result, even if network resources are insufficient, control is performed so that the network resources required to satisfy the QoS desired by the remote terminal 10B-X can be secured.

<Processing procedure>
(1) Notification of acceptability of QoS request (1.1)
FIG. 3 is a sequence diagram showing an example of the processing procedure (pattern 1) when notifying the QoS status. In the example of FIG. 3, when the SMF 32 rejects the QoS request (the PDU session change), the relay terminal 10A determines that network resources are tight, and indicates that the QoS request cannot be accepted. Send the QoS state information indicated.

At step S101, the remote terminal 10B establishes a connection for direct communication with the relay terminal 10A operating as a layer 3 relay. Such connections may be called L2 links, PC5 links, unicast links, and so on. Also, the remote terminal 10B establishes a "PC5 QoS flow" with the relay terminal 10A. Here, it is assumed that the default QoS is applied to the PC5 QoS flow.

Subsequently, the relay terminal 10A executes the PDU session establishment procedure and creates a Uu QoS flow corresponding to the remote terminal 10B (more specifically, a Uu QoS flow used to flow the traffic of the remote terminal 10B). Here, it is assumed that the default QoS is applied to the Uu QoS flow that is created. If the relay terminal 10A has already established a PDU session, the Uu QoS flow corresponding to the remote terminal 10B may be created by executing the PDU session update procedure instead of the PDU session establishment procedure. .

When the Uu QoS flow corresponding to the remote terminal 10B is created, the upstream data from the remote terminal 10B is carried to the DN 40 via the relay terminal 10A according to the PC5 QoS flow and the Uu QoS flow. Similarly, downlink data from DN 40 is carried to remote terminal 10B via relay terminal 10A according to the Uu QoS flow and PC5 QoS flow.

The relay terminal 10A may manage the end-to-end QoS flow in the remote terminal 10B by associating and managing the created QFI of the Uu QoS flow and the PFI of the PC5 QoS flow.

In step S102, the remote terminal 10B changes the QoS applied to the PC5 QoS flow to the desired QoS (here, it is assumed to be a QoS with stricter requirements than the default QoS), so that the relay terminal 10A , an L2 link modification request including information indicating the desired QoS (hereinafter referred to as "QoS indicator") to the relay terminal 10A. The QoS indicator may be called Requested QoS. A QoS indicator may be, for example, a PQI corresponding to a desired QoS requirement or an identifier corresponding to an end-to-end QoS requirement. The QoS indicator may also include other parameters specifying communication quality.

At step S103, the relay terminal 10A converts the PQI included in the QoS indicator or the identifier corresponding to the end-to-end QoS requirement into 5QI based on the mapping table. The mapping table may be set in the relay terminal 10A from the core network 30 via NAS messages or RRC (Radio Resource Control) messages, or may be preconfigured in the relay terminal 10A. .

Subsequently, the relay terminal 10A transmits a NAS message (PDU session modification request) to the AMF 31 via the base station 20 in order to change the QoS of the Uu QoS flow corresponding to the remote terminal 10B. . The PDU session change request includes, for example, the PDU session ID, the identifier of the Uu QoS flow corresponding to the remote terminal 10B, and the QoS indicator. It should be noted that the "identifier of the Uu QoS flow corresponding to the remote terminal 10B" may be, for example, QFI or a packet filter (the same applies to the following description).

In step S104, PDU Session Modification Procedure is performed among the base station 20, AMF 31, SMF 32 and UPF 33.

Here, an overview of the PDU session change processing will be described. First, the AMF 31 transmits various information included in the PDU session change request to the SMF 32 in a PDU session update request message (Nsmf_PDUSession_UpdateSMContext). The SMF 32 determines whether or not the QoS request can be accepted based on network traffic conditions and the like. The SMF 32 may determine by any method, but for example, accepts the QoS request according to the number of PDU sessions already established with each terminal 10 or the number of bit rate guaranteed QoS flows. You may make it determine whether it is possible.

When the SMF 32 accepts the QoS request, it sends the QoS profile and QoS rules corresponding to the QoS request to the AMF 31 . The AMF 31 includes the QoS profile in the N2 message and transmits it to the base station 20, and includes the QoS rule in the NAS message and transmits it to the relay terminal 10A. Also, SMF 32 transmits UL/DL PDR corresponding to the QoS request to UPF 33 .

On the other hand, when the SMF 32 determines that the QoS request cannot be accepted, the SMF 32 provides the node (such as the AMF 31 or the PCF 34) that notified the QoS request with information indicating that the QoS request is to be rejected (hereinafter referred to as "QoS rejection information”). QoS denial information may be referred to as QoS unchangeable information. Also, the QoS rejection information may be a PDU session change rejection message. The QoS rejection information may also include information indicating the reason for rejecting the QoS request (for example, cause value).

In the example of FIG. 3, it is assumed that the SMF 32 has determined that the QoS request received from the AMF 31 cannot be accepted. It is also assumed that the SMF 32 has transmitted a PDU session change rejection message to the AMF 31 .

In step S110, the AMF 31 transmits a NAS message (PDU Session Modification Command) to the relay terminal 10A. The PDU session modification command contains QoS denial information.

In step S111, when the relay terminal 10A receives the PDU session change command including the QoS rejection information, it recognizes that the network resources are tight and the QoS request cannot be accepted. Subsequently, the relay terminal 10A transmits QoS status information (QoS=Full) indicating that the network cannot accept a QoS request with stricter requirements.

In this embodiment, the relay terminal 10A may broadcast the QoS state information at a predetermined cycle. For example, the relay terminal 10A may transmit the QoS status information through a broadcast channel. In addition, the relay terminal 10A, the QoS state information, physical sidelink discovery channel (Physical Sidelink Discovery Channel: PSDCH) may be transmitted in the physical sidelink common channel (Physical Sidelink Shared Channel: PSSCH) to transmit good too. Also, the relay terminal 10A may include the QoS state information in a predetermined area (field) within a discovery message (discovery message) and transmit it.

In step S112, the relay terminal 10A transmits an L2 link modification response (L2 link Modification Accept) to the remote terminal 10B. The L2 link change response contains QoS denial information. The L2 Link Modification Response may be any message other than the L2 Link Modification Accept to convey connection rejection due to QoS conditions.

Next, the base station 20 causes another remote terminal 10B connected to the relay terminal 10A to terminate the connection with the relay terminal 10A, or the relay terminal 10A to hand over to a band with a wider bandwidth. Suppose that for some reason, it is detected that a network resource becomes available. In this case, in step S150, the base station 20 sends information (hereinafter referred to as "QoS permission information") to the relay terminal 10A indicating that it is ready to accept a QoS request with stricter requirements. An AN (Access Network) specific resource modification message (AN (Access Network) specific resource modification) may be sent. The AN specific resource change message may be an RRC message.

In addition, when SMF 32 detects that it has become possible to accept QoS requests as a result of the availability of network resources, SMF 32 transmits a NAS message including QoS permission information to relay terminal 10A via AMF 31. You may make it The SMF 32 may transmit NAS messages including QoS grant information to all relay terminals 10A for which the SMF 32 manages PDU sessions.

In step S151, when the relay terminal 10A receives an AN-specific resource change message or a NAS message from the base station 20 or the AMF 31 indicating that the QoS request can be accepted, the relay terminal 10A can accept the QoS request. QoS status information (QoS=Normal) indicating normal status is transmitted.

In the processing procedure described above, when the remote terminal 10B is a layer 2 relay, the processing procedures of steps S102 and S112 are omitted. Further, in the processing procedure of step S103, the remote terminal 10B, not the relay terminal 10A, directly transmits to the AMF 31 a PDU session change request including a QoS indicator (for example, 5QI) corresponding to the desired QoS. Also, in the processing procedure of step S110, the AMF 31 transmits a PDU session change command including QoS rejection information to the remote terminal 10B.

Also, if the remote terminal 10B is a layer 2 relay, it is conceivable that the remote terminal 10B cannot receive NAS messages and RRC messages. Therefore, in the processing procedure of step S110, the AMF 31 transmits an N2 message (message on the N2 interface) containing the QoS rejection information to the base station 20, and the base station 20 transmits the MAC (Medium Access Message) containing the QoS rejection information. Control) message (MAC layer message, for example, MAC PDU (Protocol Data Unit) or MAC CE (Control Element)) may be notified to the relay terminal 10A. When the relay terminal 10A of the layer 2 relay receives the QoS rejection information in the MAC message from the base station 20, it transmits the QoS state information (QoS=Full) indicating that the QoS request cannot be accepted any more. You may do so. As for the processing procedure of step S150, the base station 20 may include the QoS permission information in the MAC message and transmit it to the relay terminal 10A. When the relay terminal 10A of the layer 2 relay receives the QoS permission information in the MAC message from the base station 20, the relay terminal 10A transmits QoS state information (QoS=Normal) indicating that the QoS request can be accepted. can be

(1.2)
FIG. 4 is a sequence diagram showing an example of the processing procedure (pattern 2) when notifying the QoS status. In the example of FIG. 4, when the QoS request is rejected by the base station 20, the relay terminal 10A judges that network resources are tight and is in a QoS state indicating that the QoS request cannot be accepted. Send information.

The processing procedures of steps S101 to S103 are the same as the processing procedures of steps S101 to S103 in FIG. 3, respectively, so description thereof will be omitted.

In step S104, PDU Session Modification Procedure is performed among the base station 20, AMF 31, SMF 32 and UPF 33. In the example of FIG. 4, the SMF 32 determines to accept the QoS request and sends the QoS profile and QoS rules corresponding to the QoS request to the AMF 31 . The AMF 31 includes the QoS profile in the N2 message and transmits it to the base station 20, and includes the QoS rule in the NAS message and transmits it to the relay terminal 10A. Also, the SMF 32 transmits a PDR corresponding to the QoS request to the UPF 33 .

Assume here that the base station 20 determines that it cannot accept any more QoS requests, for example, because the quality of the radio signal received from the relay terminal 10A is degraded. In this case, in step S120, the base station 20 transmits an AN specific resource modification message including QoS rejection information to the relay terminal 10A. The AN specific resource change message may be an RRC message.

In step S121, when the relay terminal 10A receives the AN-specific resource change message containing the QoS rejection information, it recognizes that the network resources are tight and the QoS request cannot be accepted. Subsequently, the relay terminal 10A transmits QoS status information (QoS=Full) indicating that the network cannot accept a QoS request with stricter requirements.

The processing procedures of steps S122, S150, and S151 are the same as the processing procedures of steps S112, S150, and S151 in FIG. 3, so description thereof will be omitted.

If the remote terminal 10B is a layer 2 relay, the base station 20 may include QoS denial information in the MAC message and transmit it to the relay terminal 10A in the processing procedure of step S120.

(1.3)
FIG. 5 is a sequence diagram showing an example of the processing procedure (pattern 3) when notifying the QoS status. In the example of FIG. 5, when the base station 20 rejects the QoS request, the base station 20 notifies the AMF 31 of the rejection of the QoS request, and the AMF 31 notifies the relay terminal 10A of the rejection of the QoS request. The relay terminal 10A determines that network resources are tight, and transmits QoS status information indicating that the QoS request cannot be accepted.

The processing procedures of steps S101 to S104 are the same as the processing procedures of steps S101 to S104 in FIG. 4, respectively, so description thereof will be omitted.

The base station 20 that has received the N2 message including the QoS profile corresponding to the QoS request from the AMF 31 cannot accept the QoS request because, for example, the quality of the radio signal received from the relay terminal 10A is degraded. Suppose you decide that you can't. In this case, the base station 20 transmits an N2 message (RAN resource notification) including QoS rejection information to the AMF 31 in step S130.

In addition, when the base station 20 detects that the QoS request cannot be satisfied after the PDU session change is completed, such as when the radio quality deteriorates after the fact, the Uu QoS An N2 message containing the flow's QFI and QoS rejection information may be sent to the AMF 31 .

At step S131, the AMF 31 that has received the N2 message containing the QoS rejection information transmits a NAS message (PDU Session Modification Command) to the relay terminal 10A. The PDU session modification command contains QoS denial information.

The processing procedures of steps S132, S133, steps S150, and S151 are the same as the processing procedures of steps S111, S112, steps S150, and S151 in FIG. 3, respectively, so description thereof is omitted.

When the remote terminal 10B is a layer 2 relay, the AMF 31 transmits an N2 message (message on the N2 interface) including QoS rejection information to the base station 20 in the processing procedure of step 131, and the base station 20 receives the QoS A MAC message including the refusal information may be notified to the relay terminal 10A. When the relay terminal 10A of the layer 2 relay receives the QoS rejection information in the MAC message from the base station 20, it transmits the QoS state information (QoS=Full) indicating that the QoS request cannot be accepted any more. You may do so.

As described above, when the QoS request is rejected, the relay terminal 10A determines that the resources of the network are tight, and the QoS state information indicating that the network cannot accept the QoS request. to send. As a result, when the remote terminal 10B searches for the relay terminal 10A and starts communication, the remote terminal 10B can select the relay terminal 10A that can accept the QoS request and attempt communication, and accepts the QoS request. It is possible to start communication without wastefully communicating with the relay terminal 10A that cannot communicate with the relay terminal 10A.

In (1.1) to (1.3) described above, the QoS denial information may include information indicating acceptable QoS or unacceptable QoS. For example, information indicating acceptable QoS may include an identifier (such as 5QI) indicating acceptable QoS characteristics. Similarly, the information indicating unacceptable QoS may include an identifier indicating unacceptable QoS characteristics (such as the value of 5QI). Also, the relay terminal 10A may transmit the QoS status information including information indicating acceptable QoS or unacceptable QoS. At this time, when operating as a layer 3 relay, the relay terminal 10A uses the identifier indicating acceptable QoS characteristics or unacceptable QoS characteristics notified from the base station 20 in the PC5 interface based on the mapping table. may be converted into an identifier (PQI or the like) indicating the QoS characteristics to be used, and the identifier indicating the QoS characteristics after conversion may be included in the QoS state information and transmitted. As a result, even in an environment in which many remote terminals 10B are connected to the relay terminal 10A, it is possible for the remote terminal 10B to increase the possibility of discovering the relay terminal 10A that can accept the QoS request.

(2) QoS control based on priority (2.1)
FIG. 6 is a sequence diagram showing an example of a processing procedure (pattern 1) in QoS control based on priority. In the example of FIG. 6, when the QoS request of the remote terminal 10B-Y is rejected by the SMF 32, the relay terminal 10A has the lowest priority among the plurality of remote terminals 10B-X communicating with the relay terminal 10A. Change or cancel the QoS of the remote terminal 10B-X to a QoS with looser requirements.

The processing procedures of steps S201, S202, and S220 are the same as those in steps S101, S102, and S103 of FIG. 3, except that the remote terminal 10B is replaced with the remote terminal 10B-Y. omitted.

In step S221, the AMF 31 transmits the QoS indicators and the like regarding the remote terminal 10B-Y included in the PDU session change request to the SMF 32 in a PDU session update request message (Nsmf_PDUSession_UpdateSMContext).

At step S222, the SMF 32 determines whether or not the QoS request indicated by the QoS indicator included in the message can be accepted based on, for example, network traffic conditions. The SMF 32 may determine by any method, but for example, accepts the QoS request according to the number of PDU sessions already established with each terminal 10 or the number of bit rate guaranteed QoS flows. You may make it determine whether it is possible. Assume here that the SMF 32 determines that the QoS request cannot be accepted.

In step S223, the SMF 32 transmits to the AMF 31 a PDU session change response (Response of Nsmf_PDUSession_UpdateSMContext) containing QoS rejection information rejecting the QoS request of the remote terminal 10B-Y. Note that the "QoS request of the remote terminal 10B-Y" means the QoS request for the Uu QoS flow corresponding to the remote terminal 10B-Y.

In step S224, the AMF 31 transmits to the relay terminal 10A a PDU Session Modification Command including QoS rejection information rejecting the QoS request of the remote terminal 10B-Y.

In step S225, the relay terminal 10A, which has received the PDU session change command including the QoS refusal information from the AMF 31, selects a remote terminal with a lower priority among the plurality of remote terminals 10B-X communicating with the relay terminal 10A. Select 10B-X. The priority of the plurality of remote terminals 10B-X may be determined in any way. For example, the priority level indicated by the PQI (or 5QI after conversion) of each remote terminal 10B-X is -X priority may be supported.

In step S226, the relay terminal 10A changes or cancels the QoS of the remote terminal 10B-X with a lower priority selected in the procedure of step S225 to a QoS with looser requirements. Sends to AMF 31 a PDU session change request containing the QoS indicator of the Uu QoS flow corresponding to .

In step S227, PDU Session Modification Procedure is performed among the base station 20, AMF 31, SMF 32 and UPF 33, and the Uu QoS flow corresponding to the remote terminal 10B-X is changed to QoS with looser requirements. or be released.

In step S228, the AMF 31 notifies the relay terminal 10A of the QoS value (5QI) changed in the procedure of step S227 or the information instructing release of the Uu QoS flow by including it in the PDU session change command.

In step S229, the relay terminal 10A converts the QoS value (5QI) notified in the procedure of step S228 into PQI based on the mapping table. Subsequently, the relay terminal 10A transmits to the remote terminal 10B-X an L2 link change signal including the converted PQI or information instructing release of the PC5 QoS flow. As a result, the PC5 QoS flow and the Uu QoS flow of the remote terminal 10B-X are changed to QoS with looser requirements or canceled. Note that releasing the PC5 QoS flow and/or the Uu QoS flow of the remote terminal 10B-X may be synonymous with disconnecting the communication of the remote terminal 10B-X.

The relay terminal 10A repeats the processing procedure of steps S220 to S229 until the QoS request of the remote terminal 10B-Y is permitted, thereby replacing the QoS of the remote terminal 10B-X with lower priority with the QoS with looser requirements. change to or cancel.

Here, suppose that it is detected that the QoS of the remote terminal 10B-X, which has a low priority, is changed or canceled to a QoS with looser requirements, resulting in an empty network resource. In this case, the SMF 32 permits the QoS request in the procedure of step S222. In this case, the process proceeds to step S240.

In step S240, PDU Session Modification Procedure is performed among the base station 20, AMF 31, SMF 32 and UPF 33, and the Uu QoS flow corresponding to the remote terminal 10B-Y is changed to the requested QoS. be.

In step S241, the AMF 31 notifies the relay terminal 10A of the QoS value (5QI) of the remote terminal 10B-Y changed in the procedure of step S240 by including it in the PDU session change command.

In step S242, the relay terminal 10A converts the QoS value (5QI) notified in the procedure of step S241 into PQI based on the mapping table, and converts the QoS of the PC5 QoS flow with the remote terminal 10B-Y to , to the converted PQI. Relay terminal 10A then transmits an L2 link change response including the converted PQI to remote terminal 10B-Y. As a result, the PC5 QoS flow and the Uu QoS flow of the remote terminal 10B-Y are changed to flows that reflect the stricter QoS requirements.

Next, the relay terminal 10A repeats the processing procedure of steps S220 to S229 to change the QoS of all the remote terminals 10B-X with lower priority to QoS with looser requirements, or It is assumed that the disconnection processing of the terminals 10B-X did not result in free network resources (that is, the message shown in the processing procedure of step S241 could not be received). In this case, the process proceeds to step S260.

In step S260, the relay terminal 10A transmits an L2 link change response including QoS rejection information to the remote terminal 10B-Y.

(2.2)
FIG. 7 is a sequence diagram showing an example of a processing procedure (pattern 2) in QoS control based on priority. In the example of FIG. 7, when the QoS request of the remote terminal 10B-Y is rejected by the SMF 32, the QoS of the remote terminal 10B-X with lower priority is changed to change the QoS of the remote terminal 10B-Y with higher priority. is changed or canceled to the SMF 32. By changing or canceling the QoS of the remote terminal 10B-X with low priority, the SMF 32 can reduce the consumption of network resources and permit the QoS request of the remote terminal 10B-Y with high priority. determine whether there is When granting the QoS request of the remote terminal 10B-Y, the SMF 32 changes the QoS of the remote terminal 10B-X and the remote terminal 10B-Y or cancels the QoS of the remote terminal 10B-X.

The processing procedures of steps S301, S302, S303, S304, S305, S306, S307 and S320 of FIG. , steps S224 and S225, the description thereof will be omitted.

In step S321, the relay terminal 10A confirms that the QoS indicator of the remote terminal 10B-Y and the QoS of the remote terminal 10B-X with low priority selected in the procedure of step S320 are subject to QoS change. Send a PDU session change request to the AMF 31, including the information shown. Note that "QoS change" means changing the QoS to a QoS with looser requirements (default QoS may be used), or disconnecting a terminal with a low priority (releasing the QoS flow). .

In step S322, the AMF 31 transmits to the SMF 32 a PDU session update request that includes the QoS indicator of the remote terminal 10B-Y and the information indicating that the QoS of the remote terminal 10B-X with low priority is subject to QoS change. do.

In step S323, the SMF 32 permits the QoS request of the remote terminal 10B-Y with a high priority by changing the QoS of the remote terminal 10B-X with a low priority to a QoS with looser requirements or canceling the QoS flow. determine whether it is possible to If it is determined that permission is not possible, the process proceeds to step S324, and if it is determined that permission is possible, the process proceeds to step S340.

The processing procedures of steps S324 and S325 are the same as the processing procedures of steps S306 and S307, respectively, so description thereof will be omitted.

In step S340, PDU Session Modification Procedure is performed among the base station 20, AMF 31, SMF 32 and UPF 33, and the Uu QoS flow corresponding to the remote terminal 10B-X is changed to QoS with looser requirements. or be released.

In step S341, the AMF 31 includes the QoS value (5QI) of the remote terminal 10B-X or information instructing release of the Uu QoS flow, which has been changed in the processing procedure of step S340, in the PDU session change command and includes it in the relay terminal 10A. to notify.

In step S342, the relay terminal 10A converts the QoS value (5QI) notified in the procedure of step S341 into PQI based on the mapping table, and converts the QoS of the PC5 QoS flow with the remote terminal 10B-X to , to the converted PQI. Subsequently, the relay terminal 10A transmits to the remote terminal 10B-X an L2 link change message including information instructing release of the converted PQI or PC5 QoS flow. As a result, the PC5 QoS flow and the Uu QoS flow of the remote terminal 10B-X are changed to QoS with looser requirements or canceled.

In step S343, PDU Session Modification Procedure is performed among the base station 20, AMF 31, SMF 32 and UPF 33, and the Uu QoS flow corresponding to the remote terminal 10B-Y is changed to the requested QoS. be.

In step S344, the AMF 31 notifies the relay terminal 10A of the QoS value (5QI) of the remote terminal 10B-Y changed in the procedure of step S343 by including it in the PDU session change command.

In step S345, the relay terminal 10A converts the QoS value (5QI) notified in the procedure of step S344 into PQI based on the mapping table, and converts the QoS of the PC5 QoS flow with the remote terminal 10B-Y to , to the converted PQI. Relay terminal 10A then transmits an L2 link change response including the converted PQI to remote terminal 10B-Y. As a result, the PC5 QoS flow and the Uu QoS flow of the remote terminal 10B-Y are changed to flows reflecting the requested QoS.

Next, the relay terminal 10A repeats the processing procedure of steps S320 to S325 to change or cancel the QoS of all the remote terminals 10B with lower priority to QoS with looser requirements. It is assumed that there was no free space (that is, the message shown in the procedure of step S341 or step S344 could not be received). In this case, the process proceeds to step S360.

The processing procedure of step S360 is the same as that of step S260 in FIG. 6, so the description is omitted.

(2.3)
FIG. 8 is a sequence diagram showing an example of a processing procedure (pattern 3) in QoS control based on priority. If the SMF 32 cannot grant the QoS request of the remote terminal 10B-Y, the SMF 32 allows the QoS of the remote terminal 10B-X with the lowest priority among the plurality of remote terminals 10B-X communicating with the relay terminal 10A. , change or cancel to a less stringent QoS.

The processing procedures of steps S401, S402, S403 and S404 are the same as the processing procedures of steps S201, S202, S220 and S221 of FIG.

At step S420, the SMF 32 determines whether or not the QoS request indicated by the QoS indicator included in the PDU session change request message can be accepted based on, for example, network traffic conditions. If it is determined that it is not acceptable, the process proceeds to step S421, and if it is determined that it is acceptable, the process proceeds to step S440.

In step S421, the SMF 32 selects the remote terminal 10B-X with the lowest priority among the plurality of remote terminals 10B-X communicating with the relay terminal 10A. For example, when the SMF 32 establishes (or changes) a PDU session in the procedure of step S401, it obtains from the relay terminal 10A a priority list of the remote terminals 10B-X communicating with the relay terminal 10A. You can do it. In the priority list, for example, QoS flows identified by PDU session IDs and QFIs may be associated with terminal priorities. The SMF 32 may select the remote terminal 10B-X with low priority (or the Uu QoS flow corresponding to the remote terminal 10B-X with low priority) based on the priority list.

Also, the SMF 32 determines the priority level indicated by the value of 5QI in each QoS flow among all QoS flows (Uu QoS flows) associated with one or more PDU sessions established with the relay terminal 10A. may be considered to correspond to the priority of each remote terminal 10B-X. Also, if there are multiple QoS flows with the lowest priority level, the SMF 32 may select any one QoS flow from among these multiple QoS flows.

The processing procedures of steps S422, S423, and S424 are the same as the processing procedures of steps S340, S341, and S342 in FIG. 7, respectively, so description thereof will be omitted.

It should be noted that the SMF 32 may repeatedly execute the processing procedures of steps S420 to S422 until it can determine that the QoS request of the remote terminal 10B-Y can be accepted in the processing procedure of step S420. As a result, the processing procedure of steps S423 and S424 is executed for the remote terminal 10B-X with a low priority, and the QoS is changed to a less demanding QoS or the QoS flow is canceled. In addition, in the processing procedure of steps S420 and S421, the SMF 32 preliminarily selects one or more remote terminals 10B-X that need to be changed or canceled to QoS with looser requirements in order to accept the QoS request of the remote terminal 10B-Y. It is also possible to determine and perform the procedure of step S422 for each of the determined one or more remote terminals 10B-X. As a result, the processing procedure of steps S423 and S424 is executed for the remote terminal 10B-X with a low priority, and the QoS is changed to a less demanding QoS or the QoS flow is canceled.

The processing procedures of steps S440, S441, and S442 are the same as the processing procedures of steps S343, S344, and S345 in FIG. 7, respectively, so description thereof will be omitted.

Next, the SMF 32 determined that the QoS request of the remote terminal 10B-Y could not be accepted even if the QoS of all the remote terminals 10B-X with lower priority were changed or canceled to the QoS with looser requirements. If so, the process proceeds to step S460.

The processing procedures of steps S460, S461, and S462 are the same as the processing procedures of steps S306, S307, and S360 in FIG. 7, respectively, so description thereof will be omitted.

(2.4)
FIG. 9 is a sequence diagram showing an example of a processing procedure (pattern 4) in QoS control based on priority. In the example of FIG. 9, the QoS request for remote terminal 10B-Y is sent from AF . Further, when the SMF 32 cannot permit the QoS requested by the AF 35, the SMF 32 allows the QoS of the remote terminal 10B-X with the lowest priority among the plurality of remote terminals 10B-X communicating with the relay terminal 10A. , change or cancel to a less stringent QoS.

The processing procedure of step S501 is the same as the processing procedure of step S201 in FIG. 6, so the description is omitted.

In step S502, the remote terminal 10B-Y performs a service setup procedure with the AF 35 using the application layer interface.

In step S503, the AF 35 sends to the PCF 34 information specifying the Uu QoS flow of the remote terminal 10B-Y (for example, PDU session ID and QFI) and a service requirement including a QoS indicator for the Uu QoS flow. ) using messages on the N5 interface.

At step S504, the PCF 34 transmits to the SMF 32 a QoS modification request message (QoS Modification) including information specifying the Uu QoS flow of the remote terminal 10B-Y and the QoS indicator for the Uu QoS flow.

At step S520, the SMF 32 determines whether or not the QoS request indicated by the QoS indicator included in the QoS change request message can be accepted, based on network traffic conditions and the like. If it is determined that it cannot be accepted, the process proceeds to step S521, and if it is determined that it is acceptable, the process proceeds to step S540.

The processing procedure of step S521 is the same as the processing procedure of step S422 in FIG. 8, so the description is omitted.

In step S522, the SMF 32 transmits to the AMF 31 a PDU session change notification message (Nsmf_PDUSession_SMContextStatusNotify) indicating that the QoS of the remote terminal 10B-X with lower priority is changed or canceled to a QoS with looser requirements.

In step S523, the AMF 31 transmits a NAS message (PDU Session Modification Command) indicating that the QoS of the Uu QoS flow corresponding to the remote terminal 10B-X is changed or released. 10A.

At step S524, the relay terminal 10A transmits to the AMF 31 a NAS message (PDU Session Modification Request) indicating that the QoS of the remote terminal 10B-X is to be changed or canceled.

The processing procedures of steps S525, S526, and S527 are the same as the processing procedures of steps S340, S341, and S342 in FIG. 7, respectively, so description thereof will be omitted.

The processing procedures of steps S540, S541, and S542 are the same as the processing procedures of steps S343, S344, and S345 in FIG. 7, respectively, so description thereof will be omitted.

Next, the SMF 32 determined that the QoS request of the remote terminal 10B-Y could not be accepted even if the QoS of all the remote terminals 10B-X with lower priority were changed or canceled to the QoS with looser requirements. If so, the process proceeds to step S560.

At step S560, the SMF 32 transmits to the PCF 34 a QoS change response message containing QoS denial information.

At step S561, the PCF 34 sends a service requirement response containing QoS denial information using a message on the N5 interface.

As described above, when the QoS request is rejected, by changing or canceling the QoS of the remote terminal 10B with lower priority, the consumption of network resources can be reduced, and the remote terminal 10B with strict QoS requirements can communicate. made it possible to do As a result, the remote terminal 10B, which performs high-priority communication such as mission-critical communication, can start communication according to the QoS requirements desired by the network even when network resources are tight.

<Hardware configuration>
FIG. 10 is a diagram showing an example of the hardware configuration of each device in the communication system according to this embodiment. Each device within the communication system 1 can be any device shown in FIG. Reference numeral "30" in FIG. 10 denotes a core network device in the core network 30, and collectively refers to AMF 31, SMF 32, UPF 33, PCF 34 and AF 35. FIG.

Each device in the communication system 1 includes a processor 11, a storage device 12, a communication device 13 for wired or wireless communication, an input device for receiving various input operations, and an input/output device 14 for outputting various information.

The processor 11 is, for example, a CPU (Central Processing Unit) and controls each device within the communication system 1 . The processor 11 may read and execute the program from the storage device 12 to execute various processes described in this embodiment. Each device within the communication system 1 may be configured with one or more processors 11 . Each device may also be called a computer.

The storage device 12 is composed of storage such as memory, HDD (Hard Disk Drive) and/or SSD (Solid State Drive). The storage device 12 may store various types of information necessary for execution of processing by the processor 11 (for example, programs executed by the processor 11, etc.).

The communication device 13 is a device that communicates via a wired and/or wireless network, and may include, for example, network cards, communication modules, chips, antennas, and the like. In the case of the terminal 10 and the base station 20, the communication device 13 may include an amplifier, an RF (Radio Frequency) device that performs processing related to radio signals, and a BB (BaseBand) device that performs baseband signal processing. good.

The input/output device 14 includes input devices such as keyboards, touch panels, mice and/or microphones, and output devices such as displays and/or speakers.

The hardware configuration described above is just an example. Each device in the communication system 1 may omit part of the hardware shown in FIG. 10, or may include hardware not shown in FIG. Also, the hardware shown in FIG. 10 may be configured by one or a plurality of chips.

<Functional block configuration>
(relay terminal)
FIG. 11 is a diagram showing a functional block configuration example of the relay terminal 10A. As shown in FIG. 11 , relay terminal 10A has receiving section 101 , transmitting section 102 and control section 103 .

All or part of the functions realized by the receiving unit 101 and the transmitting unit 102 can be realized using the communication device 13. All or part of the functions realized by the receiving unit 101 and the transmitting unit 102 and the control unit 103 can be realized by the processor 11 executing a program stored in the storage device 12 . Also, the program can be stored in a storage medium. The storage medium storing the program may be a non-transitory computer readable medium. The non-temporary storage medium is not particularly limited, but may be a storage medium such as a USB memory or CD-ROM, for example.

The receiving unit 101 receives the downstream signal. Also, the receiving section 101 may receive information and/or data transmitted via a downlink signal. Here, "receiving" may include, for example, performing processing related to reception such as at least one of receiving, demapping, demodulating, decoding, monitoring, and measuring radio signals.

The transmission unit 102 transmits an upstream signal. Also, the transmitting section 102 may transmit information and/or data transmitted via an uplink signal. Here, "transmitting" may include performing processing related to transmission, such as at least one of encoding, modulation, mapping, and transmission of radio signals. In the following description, QoS change includes QoS release (QoS flow release).

The control unit 103 performs various controls in the relay terminal 10A. For example, the control unit 103 performs control to relay communication between the remote terminal 10B, the base station 20, and the core network 30 (network device). In addition, the control unit 103 controls the value (first QoS value, PQI) indicating the QoS requirements of the QoS flow (first QoS flow, PC5 QoS flow) between the remote terminal 10B, the base station 20 and the core network 30 (network device), and A value (second QoS value, 5QI) indicating the QoS requirements of the QoS flow (second QoS flow, Uu QoS flow) between Uu QoS flows is converted to each other using a mapping table.

Further, when the receiving unit 101 receives a QoS request (QoS indicator) from the remote terminal 10B (terminal 10), the transmitting unit 102 (first transmitting unit) transmits the QoS request to the AMF 31 (network device) ( 3, 4 and 5).

Also, the receiving unit 101 receives QoS rejection information (first information) indicating rejection of the QoS request from the AMF 31 (FIGS. 3, 4, and 5). Also, the receiving unit 101 may receive an RRC message including QoS rejection information (FIG. 4). Also, the receiving unit 101 may receive a NAS message including QoS rejection information (FIGS. 3 and 5). The QoS rejection information is information indicating rejection of the QoS request, and may include information indicating the reason for rejecting the QoS request (S110 in FIG. 3).

Further, when receiving the QoS rejection information, the transmitting unit 102 (second transmitting unit) transmits QoS state information (message) including information indicating that the QoS request cannot be accepted (FIG. 3). , FIGS. 4 and 5). Note that the transmission unit 102 may broadcast the QoS state information to the terminals 10 in the vicinity.

Further, the receiving unit 101 may receive QoS permission information (second information) indicating permission of the QoS request from the AMF 31 (network device) or the base station 20 (FIGS. 3, 4 and 4). 5).

Further, when the receiving unit 101 receives the QoS permission information, the transmitting unit 102 (second transmitting unit) transmits QoS state information (message) indicating that the QoS request can be accepted. (Figs. 3, 4 and 5).

When the receiving unit 101 receives a QoS request (QoS indicator) from the remote terminal 10B-Y (first terminal), the transmitting unit 102 transmits the QoS request to the AMF 31 (network device) (S220 in FIG. 6). .

Also, the receiving unit 101 receives QoS rejection information indicating rejection of the QoS request from the AMF 31 (network device) (S224 in FIG. 6).

Also, when the receiving unit 101 receives the QoS rejection information, the control unit 103 selects the remote terminal 10B-X (second terminal) from among the one or more remote terminals 10B communicating with the relay terminal 10A. The control unit 103 may select a remote terminal 10B-X (second terminal) having a lower priority than the remote terminal 10B-Y (first terminal) from among one or more remote terminals 10B ( S225 in FIG. 6).

Also, the transmitting unit (second transmitting unit) transmits a message (PDU session change request) requesting to change the QoS request of the remote terminal 10B-X (second terminal) to the AMF 31 (network device) ( S226 in FIG. 6).

(base station)
FIG. 12 is a diagram showing a functional block configuration example of the base station 20. As shown in FIG. As shown in FIG. 12 , base station 20 has receiver 201 , transmitter 202 , and controller 203 .

All or part of the functions realized by the receiving unit 201 and the transmitting unit 202 can be realized using the communication device 13. All or part of the functions realized by the receiving unit 201 and the transmitting unit 202 and the control unit 203 can be realized by the processor 11 executing a program stored in the storage device 12 . Also, the program can be stored in a storage medium. The storage medium storing the program may be a computer-readable non-temporary storage medium. The non-temporary storage medium is not particularly limited, but may be a storage medium such as a USB memory or CD-ROM, for example.

The receiving unit 201 receives an upstream signal. Also, the receiving section 101 may receive information and/or data transmitted via an uplink signal. Here, "receiving" may include, for example, performing processing related to reception such as at least one of receiving, demapping, demodulating, decoding, monitoring, and measuring radio signals.

The transmission unit 202 transmits a downlink signal. Also, the transmitting section 102 may transmit information and/or data transmitted via a downlink signal. Here, "transmitting" may include performing processing related to transmission, such as at least one of encoding, modulation, mapping, and transmission of radio signals.

The control unit 203 performs scheduling processing in the radio layer. Further, control section 203 detects whether or not there is a free wireless resource (network resource) with relay terminal 10A. More specifically, it may be a case where it is detected that the usage rate of radio resources has become equal to or less than a predetermined threshold. When control section 203 detects that a radio resource becomes available, transmitting section 202 transmits QoS permission information (second information) indicating that the QoS request is permitted to relay terminal 10A. can be Further, transmitting section 202 may transmit the QoS grant information to relay terminal 10A in an RRC message or may transmit it to relay terminal 10A in a MAC message.

(AMF)
FIG. 13 is a diagram showing a functional block configuration example of the AMF 31. As shown in FIG. As shown in FIG. 13 , AMF 31 has receiver 301 , transmitter 302 , and controller 303 .

All or part of the functions realized by the receiving unit 301 and the transmitting unit 302 can be realized using the communication device 13. All or part of the functions realized by the receiving unit 301 and the transmitting unit 302 and the control unit 303 can be realized by the processor 11 executing a program stored in the storage device 12 . Also, the program can be stored in a storage medium. The storage medium storing the program may be a computer-readable non-temporary storage medium. The non-temporary storage medium is not particularly limited, but may be a storage medium such as a USB memory or CD-ROM, for example.

The receiving unit 301 receives signals from the base station 20 or other devices within the core network 30 . Further, receiving section 301 (first receiving section) receives a QoS request from relay terminal 10A (S103 in FIG. 5).

The transmitting unit 302 transmits signals to the base station 20 or other devices within the core network 30 . Also, the transmitter 302 (first transmitter) transmits the QoS request to the SMF 32 (another core network device) (S104 in FIG. 5).

The control unit 303 performs control necessary for the AMF 31 to perform various operations described in this embodiment.

Also, the receiving unit 301 (second receiving unit) receives a QoS request from the SMF 32 (S104 in FIG. 5).

Also, the transmission unit 302 (second transmission unit) transmits a QoS request to the base station 20 (S104 in FIG. 5). Further, when receiving section 301 receives information indicating that the QoS request is rejected from base station 20 (S130 in FIG. 5), transmitting section 302 (third transmitting section) sends relay terminal 10A to: QoS rejection information (first information) indicating rejection of the QoS request is transmitted to the relay terminal 10A (S131 in FIG. 5).

(SMF)
FIG. 14 is a diagram showing a functional block configuration example of the SMF 32. As shown in FIG. As shown in FIG. 14, the SMF 32 has a receiver 401, a transmitter 402, and a controller 403. FIG.

All or part of the functions realized by the receiving unit 401 and the transmitting unit 402 can be realized using the communication device 13. All or part of the functions realized by the receiving unit 401 and the transmitting unit 402 and the control unit 403 can be realized by the processor 11 executing a program stored in the storage device 12 . Also, the program can be stored in a storage medium. The storage medium storing the program may be a computer-readable non-temporary storage medium. The non-temporary storage medium is not particularly limited, but may be a storage medium such as a USB memory or CD-ROM, for example.

The receiving unit 401 receives signals from other devices within the core network 30 .

The transmitter 402 transmits signals to other devices within the core network 30 .
The control unit 403 performs control necessary for the SMF 32 to perform various operations described in this embodiment. Also, the control unit 403 determines whether or not it is possible to accept the QoS request based on the traffic state of the network (S305 in FIG. 7).

Further, the receiving unit 401 receives a QoS request from the remote terminal 10B-Y (first terminal) communicating with the relay terminal 10A and a QoS request from the remote terminal 10B-X (second terminal) from the relay terminal 10A via the AMF 31. (S321 in FIG. 7).

Further, when the QoS request of remote terminal 10B-Y (first terminal) can be accepted by changing the QoS request of remote terminal 10B-X (second terminal), control unit 403 changes the QoS request of remote terminal 10B-X (second terminal). - Perform processing to change the QoS of X (the second terminal) to a predetermined QoS (S340 in FIG. 7). A predetermined QoS may be, for example, a default QoS.

The receiving unit 401 receives the QoS request of the remote terminal 10B-Y (first terminal) communicating with the relay terminal 10A from the relay terminal 10A or AF 35 (another core network device) via the AMF 31 or PCF 34 (Fig. 8, S503 and S504 in FIG. 9).

Further, the control unit 403 changes the QoS of one or more remote terminals 10B-X (second terminals) selected from one or more remote terminals 10B communicating with the relay terminal 10A, thereby When the QoS request of (the first terminal) can be accepted, the process of changing the QoS of the one or more remote terminals 10B-X (the second terminal) to a predetermined QoS is performed (S440 in FIG. 8, FIG. 9 S525). A predetermined QoS may be, for example, a default QoS.

Further, the control unit 403 selects one or more remote terminals 10B-X (second terminal) having a lower priority than the remote terminal 10B-Y (first terminal) from among the one or more remote terminals 10B. can be Based on the priority level specified for each QoS flow corresponding to each remote terminal 10B, the control unit 403 selects one or more remote terminals 10B-X having a lower priority than the remote terminal 10B-Y (first terminal). (Second terminal) may be selected.

Also, when the control unit 403 determines that the QoS request can be accepted, the transmission unit 402 may transmit to the AMF 31 information indicating that the QoS request is permitted.

<Other embodiments>
Various signals, information and parameters in the above embodiments may be signaled in any layer. That is, the above-mentioned various signals, information, parameters are higher layers (eg, Non Access Stratum (NAS) layer, RRC layer, MAC layer, etc.), lower layers (eg, physical layer), etc. Signals, information, may be replaced by parameters. Further, the notification of the predetermined information is not limited to being performed explicitly, but may be performed implicitly (for example, by not notifying the information or using other information).

Also, the names of various messages, signals, information, and parameters in the above embodiments are merely examples, and may be replaced with other names. For example, a slot may be named any unit of time having a predetermined number of symbols. Also, RB may be any name as long as it is a frequency unit having a predetermined number of subcarriers.

In addition, the use of the terminal 10 in the above embodiment is not limited to those illustrated, as long as it has similar functions, any use (for example, eMBB, URLLC, Device-to-Device (D2D), Vehicle-to- Everything (V2X), etc.). Also, the format of various information is not limited to the above embodiment, and may be appropriately changed to bit representation (0 or 1), true/false value (Boolean: true or false), integer value, character, or the like. Also, singularity and plurality in the above embodiments may be interchanged.

The embodiments described above are for facilitating understanding of the present disclosure, and are not for limiting interpretation of the present disclosure. Flowcharts, sequences, elements included in the embodiments, their arrangement, indexes, conditions, and the like described in the embodiments are not limited to those illustrated and can be changed as appropriate. Moreover, it is possible to partially replace or combine at least part of the configurations described in the above embodiments.

Claims (8)

1. a first transmission unit configured to transmit the QoS request to the network device when receiving the QoS request from the first terminal;
   a receiving unit that receives information indicating rejection of the QoS request from the network device;
   a control unit that selects a second terminal from among one or more terminals communicating with the relay terminal when the information is received;
   a second transmission unit configured to transmit a message to the network device requesting to change the QoS requirements of the second terminal;
   relay terminal.
2. The control unit selects the second terminal having a lower priority than the first terminal from among the one or more terminals.
   The relay terminal according to claim 1.
3. a receiving unit for receiving, from a relay terminal, a message including a QoS request for a first terminal communicating with the relay terminal and a request for changing QoS for a second terminal;
   a control unit that performs processing for changing the QoS of the second terminal when the QoS request of the first terminal can be accepted by changing the QoS of the second terminal;
   A core network device having
4. a receiving unit that receives, from a relay terminal or another core network device, a QoS request of a first terminal that communicates with the relay terminal;
   When the QoS request of the first terminal can be accepted by changing the QoS of one or more second terminals selected from among the one or more terminals communicating with the relay terminal, the one or more second A control unit that performs processing for changing the QoS of the terminal;
   A core network device having
5. The control unit selects, from among the one or more terminals, the one or more second terminals having a lower priority than the first terminal.
   The core network device according to claim 3.
6. upon receiving a QoS request from a first terminal, sending said QoS request to a network device;
   receiving information from the network device indicating a denial of the QoS request;
   selecting a second terminal from among one or more terminals communicating with the relay terminal when the information is received;
   sending a message to the network device requesting to change the QoS requirements of the second terminal;
   A relay method executed by a relay terminal including
7. receiving from a relay terminal a message containing a QoS request of a first terminal communicating with the relay terminal and a request to change the QoS of a second terminal;
   performing a process of changing the QoS of the second terminal when the QoS request of the first terminal can be accepted by changing the QoS of the second terminal;
   A communication method performed by a core network device, comprising:
8. receiving, from a relay terminal or other core network device, a QoS request for a first terminal communicating with the relay terminal;
   When the QoS request of the first terminal can be accepted by changing the QoS of one or more second terminals selected from among the one or more terminals communicating with the relay terminal, the one or more second performing a process of changing the QoS of the terminal;
   A communication method performed by a core network device, comprising:

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