JP2023019054A - Relay terminal and communication method - Google Patents

Abstract

To reduce the amount of consumption of network resources consumed when communication by a relay scheme is performed.SOLUTION: A relay terminal includes: a receiving unit that receives, from a terminal, a message containing an area identification information list indicating areas where the terminal is permitted or not permitted to communicate with a network; a control unit that determines whether the terminal is allowed to communicate with the network based on area identification information received from the network and the area identification information list; and a transmission unit that transmits a response message responding to the message to the terminal when the terminal is allowed to communicate with the network.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to relay terminals 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 also been specified as a successor to Evolved Packet Core (EPC), which is the 4th generation Core Network (CN) (for example, , Non-Patent Document 2).

3GPP TS 38.300 V15.2.0 (2018-06) 3GPP TS 23.501 V15.2.0 (2018-06)

Inter-device communication called Proximity based Services (ProSe) is currently under study. Proximity services being considered for 5G are also called 5G ProSe. In addition, in 5G ProSe, studies are also underway on relay communication, in which a terminal (Remote UE) communicates with a network via a relay terminal (Relay UE).

Here, NR is equipped with a service area restriction function (Service Area Restriction) that limits the area in which a terminal can communicate. If a terminal attempting to communicate with the network via a relay terminal exists in an area where communication is not permitted, the network will reject the connection from that terminal. As a result, when the terminal is located in an area where communication is not permitted, there is a problem that network resources consumed by the processing procedure until the network refuses connection of the terminal are wasted.

The present disclosure has been made in view of such circumstances, and aims to provide a relay terminal and a communication method that make it possible to reduce the amount of network resource consumption that occurs when communication is performed using the relay method. aim.

A relay terminal according to an aspect of the present disclosure includes a receiving unit that receives from a terminal a message including an area identification information list indicating areas in which the terminal is permitted or not permitted to communicate with a network, and receives from the network: a control unit for determining whether or not the terminal can communicate with the network based on the area identification information and the area identification information list; and responding to the message when the terminal can communicate with the network. and a transmitting unit configured to transmit a response message to the terminal.

Advantageous Effects of Invention According to the present disclosure, it is possible to provide a relay terminal and a communication method capable of reducing consumption of network resources that occur when communication is performed using a relay scheme.

It is a figure which shows an example of the outline|summary of the communication system which concerns on this embodiment. FIG. 4 is a diagram for explaining service area restrictions; FIG. 3 is a diagram showing an example of a processing procedure when a remote terminal connects to a network via a relay terminal; FIG. 10 is a diagram showing an example of a relay discovery procedure according to model A; FIG. 10 is a diagram showing an example of a relay discovery procedure according to model B; FIG. 11 is a sequence diagram showing an example of a processing procedure A1a; FIG. 11 is a sequence diagram showing an example of a processing procedure A1b; FIG. 11 is a sequence diagram showing an example of a processing procedure A2a; FIG. 11 is a sequence diagram showing an example of a processing procedure A2b; FIG. 11 is a sequence diagram showing an example of a processing procedure B1; FIG. 11 is a sequence diagram showing an example of a processing procedure B2a; FIG. 11 is a sequence diagram showing an example of a processing procedure B2b; It is a figure which shows an example of the hardware configuration of each apparatus in the communication system which concerns on this embodiment. FIG. 4 is a diagram showing a functional block configuration example of a relay terminal; It is a figure which shows the functional block structural example of a remote terminal.

Hereinafter, this embodiment will be described with reference to the accompanying drawings. In order to facilitate understanding of the description, the same constituent elements in each drawing are denoted by the same reference numerals as much as possible, and overlapping descriptions are omitted.

<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 UE) 10A, a remote terminal (Remote UE) 10B, a base station 20, a core network 30, and a Data Network (DN) 40. Note that the numbers of the relay terminals 10A, the remote terminals 10B, the base stations 20, and the 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 the relay terminal 10A and the remote terminal 10B are not distinguished from each other, they are referred to 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 relay terminal 10A and the remote terminal 10B have the same functions, and may be arbitrarily switched 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 functions necessary to operate as a relay terminal and a remote terminal, respectively. Also, the relay terminal 10A and the remote terminal 10B may have a function of operating as a normal terminal 10. FIG. Also, the relay terminal 10A may be referred to as a "relay terminal". Also, the relay terminal 10A and/or the remote terminal 10B may be simply referred to as a "terminal".

The terminal 10 is configured to be able to communicate using, for example, LTE, LTE-Advanced, NR, etc. as a radio access technology (Radio Access Technology: RAT) for the base station 20, but is not limited to this. may be configured to be able to communicate using the RAT of 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 uses the cells C to communicate with the terminal 10 . The base station 20 includes gNodeB (gNB), en-gNB, Radio Access Network (RAN), Access Network (AN), 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, an Access and Mobility Management Function (AMF) 31, a Session Management Function (SMF) 32, a User Plane Function (UPF) 33, a Policy and Control Function (PCF) 34, an Application Function (AF) 35, and the like. include.

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

Note that 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 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 called a “core network device”.

In this embodiment, the base station 20 and core network 30 are collectively referred to as "network 100".

(Mobility Restrictions)
The movement restriction function is a function of restricting movement management and access of the terminal 10 . A mobility restriction function is provided by the terminal 10 , the base station 20 and the core network 30 . The movement restriction function is RAT restriction, Forbidden Area, Service Area Restriction, Core Network type restriction and Closed Access Group information. Configured.

FIG. 2 is a diagram for explaining service area restrictions. The service area restriction defines the area in which the terminal 10 can initiate communication with the network 100 and the area in which it cannot initiate communication. More specifically, within the Allowed Area, the terminal 10 is permitted to initiate communication with the network 100 according to a subscription. On the other hand, in the non-allowed area (Non-Allowed Area), the service of the terminal 10 is restricted based on the usage contract (subscription). For example, within the unauthorized area the terminal 10 and the network 100 are not allowed to initiate service requests or any connection requests for user plane data, control plane data, exception data reporting, etc. FIG. A unit of area where communication is restricted may be a tracking area (TA). In the example shown in FIG. 2, the terminal 10-1 has TA-2 and TA-3 set as non-permission areas, and the terminal 10-2 has TA-2, TA-5 and TA-6 as non-permission areas. set in the area. In this case, the terminal 10-1 existing within the area TA-1 can communicate with the network 100. FIG. On the other hand, the terminal 10-2 existing in the area TA-2 cannot communicate with the network 100. FIG.

(relay between terminals and networks)
Currently, in NR, as a specification of proximity service (ProSe) using terminal-to-terminal communication, a remote terminal 10B communicates with the network 100 via a relay terminal 10A. ) are being considered. The relay terminal 10A is also called a ProSe UE-to-Network Relay. Also, the relay terminal 10A may be called a relay terminal for proximity service. Also, the relay terminal 10A and the remote terminal 10B support terminal-to-terminal communication (D2D communication, Sidelink communication).

The interface between terminal 10 and base station 20 is called Uu. Since the relay terminal 10A is also a type of terminal 10, the interface between the relay terminal 10A and the base station 20 is also called Uu. An interface between the remote terminal 10B and the relay terminal 10A is called PC5. These interfaces are also called reference points.

In addition, 3GPP is considering Layer 3 UE-to-Network Relay and Layer 2 UE-to-Network Relay as relays between terminals and networks. Layer 3 relay is a form in which the relay terminal 10A terminates the NAS (Non Access Stratum) layer and establishes a PDU (Protocol Data Unit) session used for communication with the remote terminal 10B. 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 communication of the remote terminal 10B.

(direct discovery)
In the proximity service of NR, a processing procedure called direct discovery (5G ProSe Direct Discovery) is stipulated for detecting and identifying other terminals 10 in close proximity via the PC 5 . Direct discovery may be used alone, or may be used to subsequently execute a procedure for communicating between terminals 10 via PC 5, called direct communication (5G ProSe Direct Communication). Direct discovery can also be used in terminal-to-network relay when remote terminal 10B detects and identifies relay terminal 10A, or when relay terminal 10A detects and identifies remote terminal 10B. Additionally, direct discovery is available for both Layer 2 and Layer 3 relays. Direct discovery used in terminal and inter-network relay is also called UE to Network Relay Discovery.

FIG. 3 is a diagram showing an example of a processing procedure when the remote terminal 10B connects to the network 100 via the relay terminal 10A. Note that FIG. 3 is applicable to both layer 2 relay and layer 3 relay.

In step S10, the remote terminal 10B detects the relay terminal 10A using the direct discovery procedure.

At step S20, the remote terminal 10B establishes a PC5 connection with the relay terminal 10A.

At step S30, the remote terminal 10B makes a registration request to the network 100 via the relay terminal 10A.

In step S40, the network 100 notifies the remote terminal 10B via the relay terminal 10A of the completion or failure of registration with the network 100. FIG.

In step S50, when the remote terminal 10B is notified of the registration failure from the network 100, the remote terminal 10B discovers the other relay terminal 10A by performing the processing procedure of step S10 again. The processing after step S20 may be performed between the terminal 10 and the relay terminal 10A.

Here, two models, Model A and Model B, are defined for the direct discovery in the procedure of step S10.

(Direct Discovery: Model A)
Model A is a model in which a terminal 10 announces "I am here" and another terminal 10 monitors it, thereby realizing direct discovery. More specifically, in the case of model A, there are two terminals 10 serving as an announcing terminal (announcing UE) and a monitoring terminal (monitoring UE). The announce terminal 10 broadcasts a discovery message at a predetermined cycle, and the monitor terminal 10 discovers the announce terminal 10 by monitoring the discovery message.

FIG. 4 is a diagram showing an example of a relay discovery procedure according to model A. As shown in FIG. In FIG. 4, the relay terminal 10A corresponds to the announcing terminal 10 (announcing UE), and the remote terminals 10B-1 and 10B-2 correspond to the monitor terminal 10 (monitoring UE).

In step S11, the relay terminal 10A broadcasts (transmits) a relay discovery announcement message (UE-to-Network Relay Discovery Announcement message). A remote terminal 10B interested in the relay discovery announcement message (ie, a terminal looking for a relay) discovers the relay terminal 10A by monitoring the relay discovery announcement message. The relay discovery announcement message includes predetermined information (eg, announcer info and/or relay service code (RSC)) that can be used by the remote terminal 10B to identify the relay terminal 10A. The remote terminal 10B can select whether or not to connect to the discovered relay terminal 10A using the predetermined information included in the received relay discovery announcement message.

In step S12, the relay terminal 10A may broadcast (transmit) relay discovery additional information messages (UE-to-Network Relay Discovery Additional Information messages) as necessary. The relay discovery additional information message may be used, for example, when the remote terminal 10B selects the relay terminal 10A and for maintaining the connection between the remote terminal 10B and the relay terminal 10A. Also, the relay discovery additional information message may include system information in the serving cell of the relay terminal 10A.

(Direct Discovery: Model B)
Model B is a model in which the terminal 10 realizes direct discovery by asking "Who is there?/Are you there?". In the case of model B, there are terminals 10 that play two roles: a terminal that wants to discover another terminal (discoverer terminal: Discoverer UE) and a terminal that wants to be discovered by another terminal (discoveree terminal: Discoveree UE). A terminal 10 (Discoverer UE) desiring to discover another terminal 10 transmits a request message containing certain information. Also, a terminal (Discoveree UE) that wants to be discovered by another terminal notifies the terminal (Discoverer UE) that wants to discover the other terminal of its own existence by responding to the request message.

FIG. 5 is a diagram showing an example of a relay discovery procedure according to model B. As shown in FIG. In FIG. 5, a relay terminal 10A-1 and a relay terminal 10A-2 correspond to a terminal 10 (Discoveree UE) that wants to be discovered by another terminal 10, and a remote terminal 10B corresponds to a terminal 10 that wants to discover another terminal 10 (Discoveree UE). Discoverer UE).

In step S15, the remote terminal 10B broadcasts (transmits) a relay discovery solicitation message (UE-to-Network Relay Discovery Solicitation message). The relay discovery invitation message may include, for example, predetermined information (Discoverer info and/or RSC) that can be used to identify whether the relay terminal 10A will respond to the remote terminal 10B. .

In step S16, the relay terminal 10A-1 and the relay terminal 10A-2 that have received the relay discovery and invitation message match the predetermined information included in the relay discovery and invitation message (that is, if the remote terminal 10B , the remote terminal 10B transmits a relay discovery response message (UE-to-Network Relay Discovery Response message). On the other hand, when the relay terminal 10A-1 and the relay terminal 10A-2 do not match the predetermined information included in the relay discovery and solicitation message (that is, the remote terminal 10B determines that it is not looking for itself). case), do not send a relay discovery response message. In the example of FIG. 5, only the relay terminal 10A-1 has determined that it matches the predetermined information, and has sent a relay discovery response message to the remote terminal 10B.

(Issues when service area restrictions are applied to communications via relays)
In the processing procedure when the remote terminal 10B connects to the network via the relay terminal 10A shown in FIG. Only after executing the processing procedure of step S30 and receiving a registration failure notification from the network 100, does it recognize that communication is not permitted. As described above, according to the current 3GPP specifications, even when the remote terminal 10B is in the unauthorized area, the communication processing of steps S10 to S30 is executed, which wastes network resources. I have a problem.

Therefore, in the present embodiment, the remote terminal 10B itself or the relay terminal 10A can recognize that the remote terminal 10B is in the unauthorized area in the relay discovery procedure in step S10 of FIG. As a result, when the remote terminal 10B is in the unauthorized area, the processing procedure after step S20 can be omitted, and the consumption of network resources can be reduced.
<Processing procedure>
Next, a specific processing procedure for solving the above problems will be described. The processing procedures A1a to A2b described below use the model A relay discovery procedure, and the processing procedures B1 to B3 use the model B relay discovery procedure.

In each procedure below, the unit of the area in which communication is restricted is a tracking area, and the remote terminal 10B uses a TAI (Tracking Area Identity) list indicating tracking areas in which communication with the network 100 is not permitted (that is, blacklist) is stored in advance. In addition, in the following processing procedures, the same processing procedures are denoted by the same reference numerals, and detailed description thereof will be omitted.

(Processing procedure A1a)
FIG. 6 is a sequence diagram showing an example of the processing procedure A1a.

At step S100, the network 100 (base station 20) transmits system information including the TAI. The TAI is an identifier combining MCC (Mobile Country Code), MNC (Mobile Network Code) and TAC (Tracking Area Code). System information may include MCC, MNC and TAC separately. The relay terminal 10A acquires a TAI (Tracking Area Identity) from the system information transmitted from the base station 20 of the cell in which it is located (camped on). The obtained TAI is called the serving cell's TAI.

In step S200, the relay terminal 10A broadcasts (transmits) a relay discovery announcement message including announcer information (Announcer Info), RSC and relay TAI (Relay TAI). Here, the relay TAI indicates the TAI corresponding to the serving cell of the relay terminal 10A. That is, the relay TAI transmitted by the relay terminal 10A in step S200 is the same as the TAI acquired by the relay terminal 10A in step S100.

Note that the relay discovery announcement message is sent using the source layer 2 ID and the destination layer 2 ID. In addition, when the relay terminal 10A is a layer 3 relay, the relay terminal 10A transmits NSSAI (Single-Network Slice Selection Assistance Information) associated with the RSC to the relay terminal 10A itself. ), the RSC may be included in the relay discovery announcement message.

The remote terminal 10B-1 and the remote terminal 10B-2 monitor the relay discovery announcement message, and communicate with the relay terminal 10A based on the announcer information (Announcer Info) and/or RSC included in the received relay discovery announcement message. determines whether or not to establish a PC5 connection. When the remote terminal 10B-1 and the remote terminal 10B-2 determine to establish the PC5 connection with the relay terminal 10A, the process proceeds to steps S220 and S221 respectively. When the remote terminal 10B-1 and the remote terminal 10B-2 determine that the PC5 connection is not to be established, the processing ends without proceeding to the processing procedures of steps S220 and S221.

At step S220, the remote terminal 10B-1 checks whether or not the TAI list stored therein includes the relay TAI. If the TAI list includes a relay TAI, the remote terminal 10B-1 determines that it is in the unauthorized area and is not authorized to initiate communication with the network 100. FIG. On the other hand, if the TAI list does not include the relay TAI, the remote terminal 10B-1 determines that it exists in the permitted area and is permitted to initiate communication with the network 100. FIG. Assume here that remote terminal 10B-1 has been authorized to initiate communication with network 100. FIG.

In step S221, the remote terminal 10B-2 checks whether or not the TAI list stored by itself includes the relay TAI. If the TAI list includes a relay TAI, remote terminal 10B-2 determines that it is in an unauthorized area and is not authorized to initiate communication with network 100. FIG. On the other hand, if the TAI list does not include the relay TAI, remote terminal 10B-2 determines that it is in the permitted area and is permitted to initiate communication with network 100. FIG. Assume here that remote terminal 10B-2 has not been authorized to initiate communication with network 100;

In step S300, the relay terminal 10A may broadcast (transmit) a relay discovery additional information message as necessary. The relay discovery additional information message may include system information received by the relay terminal 10A from the network 100 (base station 20) (that is, system information in the serving cell of the relay terminal 10A).

At step S500, the remote terminal 10B-1, which is permitted to start communication with the network 100, establishes a PC5 connection with the relay terminal 10A and performs registration processing with the network 100. FIG.

According to the processing procedure A1a, when it is determined that the remote terminal 10B exists in the unauthorized area and is not permitted to start communication with the network 100, the PC5 connection is established and the registration process to the network 100 is performed. do not This makes it possible to reduce the consumption of network resources.

(Processing procedure A1b)
FIG. 7 is a sequence diagram showing an example of the processing procedure A1b.

At step S110, the network 100 (base station 20) transmits system information including the TAI. Relay terminal 10A acquires the TAI from the system information transmitted from base station 20 . Here, if there is a terminal 10 for which the TAI is set in the non-permission area (that is, if there is a terminal that includes the TAI in the TAI list), the base station 20 sets the TAI to the non-permission area. is included in the system information and transmitted. Note that the base station 20 may recognize whether or not there is a terminal 10 whose TAI is set to a non-permission area by a notification from the core network 30, or an OSS (Operation Support System). It may be recognized by information set in the base station 20 via a network management device such as.

In step S111, the relay terminal 10A confirms whether or not a "non-permitted terminal presence flag" is set in the system information. The relay terminal 10A proceeds to step S200 if the "non-permitted terminal presence flag" is set, and proceeds to step S211 if the "non-permitted terminal presence flag" is not set.

In step S200, the relay terminal 10A broadcasts (transmits) a relay discovery announcement message including announcer information, RSC and relay TAI.

In step S211, the relay terminal 10A broadcasts (transmits) a relay discovery announcement message including announcer information and RSC.

In step S222, the remote terminal 10B-1 checks whether the relay discovery announcement message includes the relay TAI and whether the TAI list stored by itself includes the relay TAI. . If the relay discovery announcement message contains a relay TAI and the TAI list contains a relay TAI, the remote terminal 10B-1 itself exists in the unauthorized area and cannot communicate with the network 100. Determine that it is not allowed to start. On the other hand, if the relay discovery announcement message does not include the relay TAI, or if the relay discovery announcement message includes the relay TAI but the TAI list does not include the relay TAI, the remote terminal 10B- 1 determines that it is in the permitted area and is permitted to initiate communication with network 100 . Assume here that remote terminal 10B-1 has been authorized to initiate communication with network 100. FIG.

In step S223, the remote terminal 10B-2 confirms whether or not the relay discovery announcement message includes the relay TAI, and whether or not the TAI list stored by itself includes the relay TAI. . If the relay discovery announcement message contains the relay TAI and the TAI list contains the relay TAI, the remote terminal 10B-2 is in the unauthorized area and cannot communicate with the network 100. Determine that it is not allowed to start. On the other hand, if the relay discovery announcement message does not include the relay TAI, or if the relay discovery announcement message includes the relay TAI but the TAI list does not include the relay TAI, the remote terminal 10B-2 determines that it is in the permitted area and is permitted to initiate communication with network 100 . Assume here that remote terminal 10B-2 has not been authorized to initiate communication with network 100;

Since the processing procedure after step S300 is the same as in FIG. 6, the description is omitted.

In the procedure A1b, the relay terminal 10A transmits the relay TAI when there is a terminal 10 for which the TAI of the serving cell is set to the non-permission area. In other words, if there is no terminal 10 for which the TAI of the serving cell is set to the non-permission area, the relay terminal 10A does not transmit the relay TAI. Therefore, the processing procedure A1b can reduce the consumption of radio resources more than the processing procedure A1a.

(Processing procedure A2a)
FIG. 8 is a sequence diagram showing an example of the processing procedure A2a.

At step S100, the network 100 (base station 20) transmits system information including the TAI. Relay terminal 10A acquires the TAI from the system information transmitted from base station 20 .

In step S212, the relay terminal 10A broadcasts (transmits) a relay discovery announcement message including announcer information and RSC.

In step S310, the relay terminal 10A broadcasts (transmits) a relay discovery additional information message including the relay TAI. The relay TAI is the same as the TAI acquired by the relay terminal 10A in step S100.

At step S320, the remote terminal 10B-1 checks whether or not the TAI list stored by itself includes the relay TAI. If the TAI list includes a relay TAI, the remote terminal 10B-1 determines that it is in the unauthorized area and is not authorized to initiate communication with the network 100. FIG. On the other hand, if the TAI list does not include the relay TAI, the remote terminal 10B-1 determines that it exists in the permitted area and is permitted to initiate communication with the network 100. FIG. Assume here that remote terminal 10B-1 has been authorized to initiate communication with network 100. FIG.

In step S321, the remote terminal 10B-2 checks whether or not the TAI list stored by itself includes the relay TAI. If the TAI list includes a relay TAI, remote terminal 10B-2 determines that it is not authorized to initiate communication with network 100. FIG. On the other hand, if the TAI list does not include the relay TAI, remote terminal 10B-2 determines that it is permitted to initiate communication with network 100. FIG. Assume here that remote terminal 10B-2 has not been authorized to initiate communication with network 100;

At step S500, the remote terminal 10B-1, which is permitted to start communication with the network 100, establishes a PC5 connection with the relay terminal 10A and performs registration processing with the network 100. FIG.

According to the processing procedure A2a, when it is determined that the remote terminal 10B exists in the unauthorized area and is not permitted to start communication with the network 100, the PC5 connection is established and the registration process to the network 100 is performed. do not This makes it possible to reduce the consumption of network resources.

(Processing procedure A2b)
FIG. 9 is a sequence diagram showing an example of the processing procedure A2b.

At step S110, the network 100 (base station 20) transmits system information including the TAI. Relay terminal 10A acquires the TAI from the system information transmitted from base station 20 . Here, when there is a terminal 10 whose TAI is set in a non-permission area, the base station 20 transmits system information including a "non-permission terminal existence flag".

In step S111, the relay terminal 10A confirms whether or not a "non-permitted terminal presence flag" is set in the system information. The relay terminal 10A proceeds to step S310 after step S212 if the "non-permitted terminal presence flag" is set, and proceeds to step S312 after step S212 if the "non-permitted terminal presence flag" is not set. proceed to

In step S212, the relay terminal 10A broadcasts (transmits) a relay discovery announcement message including announcer information and RSC.

In step S310, the relay terminal 10A broadcasts (transmits) a relay discovery additional information message including announcer information, RSC and relay TAI.

In step S312, the relay terminal 10A broadcasts (transmits) a relay discovery additional information message including announcer information and RSC.

In step S322, the remote terminal 10B-1 confirms whether or not the relay discovery additional information message includes the relay TAI, and whether or not the TAI list stored by itself includes the relay TAI. do. If the relay discovery additional information message contains the relay TAI and the TAI list contains the relay TAI, the remote terminal 10B-1 is in the unauthorized area and communicates with the network 100. is not allowed to start. On the other hand, if the relay discovery additional information message does not contain the relay TAI, or if the relay discovery additional information message contains the relay TAI but the TAI list does not contain the relay TAI, the remote terminal 10B -1 determines that it is in the permitted area and is permitted to initiate communication with network 100 . Assume here that remote terminal 10B-1 has been authorized to initiate communication with network 100. FIG.

In step S323, the remote terminal 10B-2 confirms whether or not the relay discovery additional information message includes the relay TAI, and whether or not the TAI list stored by itself includes the relay TAI. do. If the relay discovery additional information message contains the relay TAI and the TAI list contains the relay TAI, the remote terminal 10B-2 is in the unauthorized area and communicates with the network 100. is not allowed to start. On the other hand, if the relay discovery additional information message does not contain the relay TAI, or if the relay discovery additional information message contains the relay TAI but the TAI list does not contain the relay TAI, the remote terminal 10B -2 determines that it is in the permitted area and is permitted to initiate communication with network 100 . Assume here that remote terminal 10B-2 has not been authorized to initiate communication with network 100;

At step S500, the remote terminal 10B-1, which is permitted to start communication with the network 100, establishes a PC5 connection with the relay terminal 10A and performs registration processing with the network 100. FIG.

In the procedure A2b, the relay terminal 10A transmits the relay TAI when there is a terminal 10 for which the TAI of the serving cell is set to the non-permission area. In other words, the relay terminal 10A does not transmit the relay TAI if there is no terminal 10 whose serving cell TAI is set to the non-permission area. Therefore, the processing procedure A2b can reduce the consumption of radio resources more than the processing procedure A2a.

(Processing procedure B1)
FIG. 10 is a sequence diagram showing an example of the procedure B1.

At step S100, the network 100 (base station 20) transmits system information including the TAI. Relay terminal 10A acquires the TAI from the system information transmitted from base station 20 .

In step S400, the remote terminal 10B broadcasts (transmits) a relay discovery invitation message including discoverer info, RSC and TAI list. If the relay terminal 10A that has received the relay discovery invitation message matches the discoverer info and/or the RSC (that is, if it determines that the remote terminal 10B is searching for itself), step S401 is performed. Proceed to the procedure for . Also, if the relay terminal 10A itself does not match the finder information or the RSC (that is, if it is determined that the remote terminal 10B is not searching for itself), the relay terminal 10A does not execute the processing procedures of steps S401 and S402. exit.

In step S401, the relay terminal 10A confirms whether or not its own TAI (relay TAI) is included in the TAI list received in step S400. If the TAI list contains its own TAI, the relay terminal 10A determines that the remote terminal 10B that transmitted the relay discovery and invitation message is in the unauthorized area and is permitted to start communication with the network 100. It is determined that there is no relay discovery response message, and the process ends without transmitting the relay discovery response message. On the other hand, if the TAI list does not contain its own TAI, the relay terminal 10A determines that the remote terminal 10B exists in the permitted area and is permitted to start communication with the network 100. , the process proceeds to step S402. Assume here that remote terminal 10B has been authorized to initiate communication with network 100 .

At step S402, the relay terminal 10A transmits a relay discovery response message to the remote terminal 10B.

In step S500, the remote terminal 10B that has received the relay discovery response message establishes a PC5 connection with the relay terminal 10A and performs registration processing with the network 100. FIG.

According to the processing procedure B1, when the relay terminal 10A determines that the remote terminal 10B exists in the non-permission area and is not permitted to start communication with the network 100, it does not respond to the relay discovery invitation message. . As a result, the relay terminal 10A does not establish the PC5 connection and does not register with the network 100, thereby reducing consumption of network resources.

(Processing procedure B2a)
FIG. 11 is a sequence diagram showing an example of the procedure B2a.

At step S100, the network 100 (base station 20) transmits system information including the TAI. Relay terminal 10A acquires the TAI from the system information transmitted from base station 20 .

In step S410, the remote terminal 10B broadcasts (transmits) a relay discovery invitation message including discoverer info and RSC. If the relay terminal 10A that has received the relay discovery invitation message matches the discoverer info and/or the RSC (that is, if it determines that the remote terminal 10B is searching for itself), step S411 is performed. proceed to If the relay terminal 10A itself does not match the finder information or the RSC (that is, if it determines that the remote terminal 10B is not searching for itself), it ends the process without proceeding to step S411.

In step S411, the relay terminal 10A transmits a relay discovery response message including the relay TAI to the remote terminal 10B. The relay TAI is the same as the TAI acquired by relay terminal 10A in step S100.

In step S420, the remote terminal 10B checks whether or not the TAI list stored by itself includes the relay TAI. If the TAI list includes a relay TAI, the remote terminal 10B determines that it is located in the unauthorized area and is not permitted to initiate communication with the network 100 . On the other hand, if the TAI list does not contain the relay TAI, the remote terminal 10B determines that it exists in the permitted area and is permitted to initiate communication with the network 100 . Assume here that remote terminal 10B has been authorized to initiate communication with network 100 .

In step S500, the remote terminal 10B, which is permitted to start communication with the network 100, establishes a PC5 connection with the relay terminal 10A and performs registration processing with the network 100. FIG.

According to the processing procedure B2a, when it is determined that the remote terminal 10B exists in the unauthorized area and is not permitted to start communication with the network 100, the PC5 connection is established and the registration process to the network 100 is performed. do not This makes it possible to reduce the consumption of network resources.

(Processing procedure B2b)
FIG. 12 is a sequence diagram showing an example of the procedure B2b.

At step S110, the network 100 (base station 20) transmits system information including the TAI. Relay terminal 10A acquires the TAI from the system information transmitted from base station 20 . Here, when there is a terminal 10 whose TAI is set in a non-permission area, the base station 20 transmits system information including a "non-permission terminal existence flag".

In step S111, the relay terminal 10A confirms whether or not a "non-permitted terminal presence flag" is set in the system information. The relay terminal 10A proceeds to step S411 after step S410 if the "flag for presence of disallowed terminals" is set, and proceeds to step S413 after step S410 if the "flag for presence of disapproved terminals" is not set. proceed to

In step S410, the remote terminal 10B broadcasts (transmits) a relay discovery invitation message including discoverer info and RSC. If the relay terminal 10A that has received the relay discovery invitation message matches the discoverer info and/or the RSC (that is, if it determines that the remote terminal 10B is searching for itself), step S411 is performed. Alternatively, the process proceeds to step S413. If the relay terminal 10A itself does not match the finder information or the RSC (that is, if it determines that the remote terminal 10B is not searching for itself), it ends the process without proceeding to steps S411 and S413.

In step S411, the relay terminal 10A transmits a relay discovery response message including the relay TAI to the remote terminal 10B.

In step S413, the relay terminal 10A transmits a relay discovery response message that does not include the relay TAI to the remote terminal 10B.

In step S421, the remote terminal 10B confirms whether or not the relay discovery response message includes the relay TAI, and whether or not the TAI list stored by itself includes the relay TAI. If the relay discovery response message contains the relay TAI and the TAI list contains the relay TAI, the remote terminal 10B itself is in the unauthorized area and starts communication with the network 100. is not permitted. On the other hand, if the relay discovery response message does not include the relay TAI, or if the relay discovery response message includes the relay TAI but the TAI list does not include the relay TAI, the remote terminal 10B It determines that it exists in the permitted area and is permitted to initiate communication with network 100 . Assume here that remote terminal 10B has been authorized to initiate communication with network 100 .

In step S500, the remote terminal 10B permitted to start communication with the network 100 establishes a PC5 connection with the relay terminal 10A and performs registration with the network 100. FIG.

In procedure B2b, the relay terminal 10A transmits the relay TAI when there is a terminal 10 whose serving cell TAI is set to the non-permission area. In other words, the relay terminal 10A does not transmit the relay TAI if there is no terminal 10 whose serving cell TAI is set to the non-permission area. Therefore, the processing procedure B2b can reduce the consumption of radio resources more than the processing procedure B2a.

(Modification)
In each processing procedure described above, the "non-permitted terminal presence flag" is a flag indicating whether or not there is a terminal 10 whose TAI is set in the non-permitted area (for example, it may be called a non-permitted terminal flag) good) can be replaced with The flag is, for example, 1 bit. When it is 0, it means that there is no terminal 10 whose TAI is set in the non-permission area, and when it is 1, the terminal whose TAI is set in the non-permission area. 10 (or vice versa). Further, in step S111, the relay terminal 10A may check whether the "non-permitted terminal presence/absence flag" included in the system information is set to "exist" or "not exist". .

In each processing procedure described above, the identifier used to identify the tracking area may be the TAC instead of the TAI. In this case, the terms of TAI list and relay TAI may be replaced with terms of TAC list and relay TAC, respectively. Since the code length is shortened, the amount of radio resources can be reduced.

In each of the processing procedures described above, the unit of area in which communication is restricted is not limited to the tracking area, and may be another unit. For example, the units of areas in which communication is restricted may be units of RAN areas or cells, which are finer granularities than tracking areas. The RAN area is a concept introduced in NR, and is an area used by the base station 20 to manage the location of the terminal 10 that is RRC inactive (RRC INACTIVE). When the RAN area unit is used, each area may be expressed by combining a TAI and a RAN area code. In this case, the TAI list and relay TAI may be referred to as RAN area ID list and relay RAN area ID, respectively. Moreover, when it is set as a cell unit, it may be expressed by a combination of a TAI and a cell ID (Physical Cell Identity: PCI). In this case, the TAI list and relay TAI may be referred to as cell ID list and relay cell ID, respectively.

In each processing procedure described above, the TAI list may be a white list. In other words, the TAI list may be a list indicating tracking areas in which communication with the network 100 is permitted. In this case, if the TAI list does not include a relay TAI, the remote terminal 10B is located in the unauthorized area and is not permitted to initiate communication with the network 100. judge not. On the other hand, if the TAI list includes the relay TAI, the remote terminal 10B determines that it exists in the permitted area and is permitted to initiate communication with the network 100 .

In the processing procedures A1a and A1b described above, when the tracking area is changed due to movement of the relay terminal 10A after transmitting the relay discovery announcement message including the relay TAI, the relay terminal 10A transmits the changed TAI. , may be included in the relay discovery additional information message and broadcast (transmitted) as the relay TAI. Further, even after the remote terminal 10B has been registered with the network 100, if it receives a relay discovery additional information message including a relay TAI different from the relay TAI included in the relay discovery announcement message, Alternatively, the processing procedure of step S320 or step S321 of No. 8 may be executed. If the relay TAI included in the relay discovery additional information message is included in the TAI list, the remote terminal 10B may execute the process of canceling registration with the network 100 via the relay terminal 10A.

<Hardware configuration>
FIG. 13 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. 13 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 in 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), for example. 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, for example, an input device such as a keyboard, touch panel, mouse and/or microphone, and an output device such as a display and/or speaker.

The hardware configuration described above is merely an example. Each device in the communication system 1 may omit part of the hardware shown in FIG. 13, or may include hardware not shown in FIG. Also, the hardware shown in FIG. 13 may be configured by one or a plurality of chips.

<Functional block configuration>
(relay terminal)
FIG. 14 is a diagram showing a functional block configuration example of the relay terminal 10A. As shown in FIG. 14 , relay terminal 10A has receiving section 101 , transmitting section 102 and control section 103 . Also, the receiving section 101 and the transmitting section 102 are collectively referred to as a communication section 110 .

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.

In the following description, tracking areas, RAN areas and cells are examples of "areas". The TAI list, TAC list, RAN area ID list and cell ID list are examples of the "area identification information list". The TAI, TAC, RAN area and cell ID, relay TAI, relay TAC, relay RAN area, and relay cell ID are examples of "area identification information." Also, TAI and TAC are examples of "tracking area identifiers."

Receiving section 101 receives a downlink 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.

Transmission section 102 transmits an uplink 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.

The control unit 103 performs various controls in the relay terminal 10A. For example, the control unit 103 controls relaying communication between the remote terminal 10B and the network 100 .

The receiving unit 101 also receives a message from the remote terminal 10B (terminal) including an area identification information list indicating areas in which the remote terminal 10B is permitted or not permitted to communicate with the network 100 (for example, step S400). The message may be, for example, a relay discovery invitation message used when the remote terminal 10B inquires about the existence of the relay terminal 10A.

Also, the receiving unit 101 receives a radio signal including area identification information from the network 100 .

Further, the control unit 103 determines whether or not the remote terminal 10B (terminal) can communicate with the network 100 based on the area identification information received from the network 100 and the area identification information list (for example, step S401 in FIG. 10). .

Further, when the remote terminal 10B (terminal) can communicate with the network 100, the transmitting unit 102 sends a response message in response to the message including the area identification information list received by the receiving unit 101 to the remote terminal 10B. Send. The response message may be a relay discovery response message used in responding to the relay discovery invite message.

In addition, when the radio signal includes an identifier (for example, a flag indicating that a terminal 10 with restricted communication with the network 100 exists) in the area corresponding to the area identification information, the transmitting unit 102 , a message including area identification information is transmitted (for example, steps S111 in FIGS. 7, 9 and 12, step S200 in FIG. 7, step S310 in FIG. 9, and step S411 in FIG. 12). The message may be a relay discovery announcement message, a relay discovery additional information message, or a relay discovery response message.

(remote terminal)
FIG. 15 is a diagram showing a functional block configuration example of the remote terminal 10B. As shown in FIG. 15, the remote terminal 10B has a receiving section 201, a transmitting section 202, and a control section 203. Also, the receiving section 201 and the transmitting section 202 are collectively referred to as a communication section 210 .

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.

Receiving section 201 receives a downlink signal. Also, the receiving section 201 may receive information and/or data transmitted via a downlink signal.

The transmitting section 202 transmits an uplink signal. Also, the transmitting section 202 may transmit information and/or data transmitted via an uplink signal.

The control unit 203 performs various controls in the remote terminal 10B. For example, the control unit 203 performs various controls required when communicating with the network 100 via the relay terminal 10A.

Also, receiving section 201 receives a message including area identification information from relay terminal 10A (for example, S200 in FIGS. 6 and 7, S310 in FIGS. 8 and 9, and S411 in FIGS. 11 and 12).

Further, control section 203 controls communication with network 100 based on area identification information included in a message received from relay terminal 10A and an area identification information list indicating areas where communication with network 100 is permitted or not permitted. 6, S222 and S223 in FIG. 7, S320 and S321 in FIG. 8, S322 and S323 in FIG. 9, S420 in FIG. 11, and S421 in FIG. 12). The message may be a discovery announcement message that announces the existence of relay terminal 10A (for example, step S200 in FIGS. 6 and 7). The message may also be a relay discovery additional information message used by the relay terminal 10A to notify additional information (for example, step S310 in FIGS. 8 and 9). Also, the message may be a relay discovery response message (for example, step S411 in FIGS. 11 and 12) used when the relay terminal 10A responds to a relay discovery invitation message received from the remote terminal 10B (terminal). .

Further, when the control unit 203 determines that communication with the network 100 is possible, the communication unit 210 (receiving unit 201 and transmitting unit 202) establishes a connection with the relay terminal 10A (Fig. 6 to step S500 in FIG. 12).

Further, when the area identification information included in the message received from the relay terminal is included in the area identification information list, communication section 210 may establish a connection with relay terminal 10A. Further, if the area identification information included in the message received from the relay terminal is not included in the area identification information list, communication section 210 may not establish a connection with relay terminal 10A.

<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, the singular and plural terms 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.

Reference Signs List 1 communication system 10 terminal 10A relay terminal 10B remote terminal 11 processor 12 storage device 13 communication device 14 input/output device 20 base station 30 core network 101 ... Reception unit 102 ... Transmission unit 103 ... Control unit 201 ... Reception unit 202 ... Transmission unit 203 ... Control unit

Claims (3)

a receiving unit for receiving, from a terminal, a message containing an area identification information list indicating areas in which the terminal is permitted or not permitted to communicate with a network;
a control unit that determines whether or not the terminal can communicate with the network based on the area identification information received from the network and the area identification information list;
a transmission unit configured to transmit a response message in response to the message to the terminal when the terminal can communicate with the network;
A relay terminal with the message is a relay discovery invitation message used when the terminal inquires about the existence of a relay terminal;
the response message is a relay discovery response message used when responding to the relay discovery invitation message;
The relay terminal according to claim 1. receiving from a terminal a message containing an area identification information list indicating areas in which said terminal is permitted or not permitted to communicate with a network;
determining whether the terminal can communicate with the network based on the area identification information received from the network and the area identification information list;
sending a response message to the terminal in response to the message if the terminal is able to communicate with the network;
The communication method performed by the relay terminal, including

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