CN117956438A

CN117956438A - Communication method and device

Info

Publication number: CN117956438A
Application number: CN202211351677.0A
Authority: CN
Inventors: 窦凤辉; 米歇尔·扎里
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2022-10-21
Filing date: 2022-10-31
Publication date: 2024-04-30

Abstract

The application relates to a communication method and a communication device. The first terminal device receives a first message from the second terminal device, the first message indicating a relay service providing an emergency service. The first terminal device determines whether to select the second terminal device and/or the first network to provide the relay service of the emergency service according to the first information, wherein the first information comprises information whether the first network requires to execute IMS registration and/or comprises network behavior information of the first network to establish emergency bearing. By the scheme of the embodiment of the application, the first terminal equipment can select the proper terminal equipment and/or network to provide the relay service of the emergency service, so that the success rate of the first terminal equipment for executing the emergency service is improved, and the safety risk is reduced.

Description

Communication method and device

Cross Reference to Related Applications

The present application claims priority from the chinese patent application filed at 2022, 10 and 21, filed with the chinese national intellectual property agency, application number 202211298169.0, application name "method for emergency services", the entire contents of which are incorporated herein by reference.

Technical Field

The present application relates to the field of communications technologies, and in particular, to a communications method and apparatus.

Background

In communication, an emergency call is one of the most important services, and refers to a call of a specific number initiated by a terminal device in an emergency. Whether an emergency call can be successfully initiated or not, a major security issue is concerned. The emergency call may be placed directly in the fourth generation (the 4th generation,4G) mobile communication system/the fifth generation (the 5th generation,5G) mobile communication system via the internet protocol (internet protocol, IP) multimedia subsystem (IP multimedia subsystem, IMS) or may be placed from the 4G/5G network back to the second generation (the 2nd generation,2G) mobile communication system/the third generation (the 3rd generation,3G) mobile communication system network. In the large trend of 2G/3G network off-line, the terminal equipment is necessary to dial an emergency call by relying on IMS in 4G/5G.

The terminal device needs to rely on the IMS network to make an emergency call, and needs to go through two procedures, one is a procedure of establishing an emergency bearer in the core network, and the other is a procedure of establishing an emergency session with the IMS. In both processes, the network may not support the request of the terminal device, so that the terminal device cannot place an emergency call. It can be seen that the success rate of the terminal device making an emergency call is low at present.

Disclosure of Invention

The embodiment of the application provides a communication method and a communication device, which are used for improving the success rate of executing emergency services by terminal equipment.

In a first aspect, a first communication method is provided, which may be performed by a terminal device, or by another device comprising the functionality of the terminal device, or by a chip system (or chip) or other functional module, which is capable of implementing the functionality of the terminal device, the chip system or functional module being provided in the terminal device, for example. The terminal device is for example a first terminal device. The method comprises the following steps: receiving a first message from a second terminal device, wherein the first message is used for indicating a relay service for providing emergency services; and determining whether to select the second terminal equipment and/or the first network to provide the relay service of the emergency service according to first information, wherein the first information comprises information whether the first network requires IMS registration execution or not and/or network behavior information of the first network for establishing emergency bearing.

In the embodiment of the application, the first terminal equipment can determine whether to select the relay service of the emergency service provided by the second terminal equipment and/or the first network according to the first information. For example, if the first terminal device does not have the IMS certificate, the first terminal device may select the relay service for providing the emergency service by the second terminal device and/or the first network if the first network does not require the IMS registration, and the first terminal device may not select the relay service for providing the emergency service by the second terminal device and/or the first network if the first network does require the IMS registration; for another example, if it is determined that the first network can support the first terminal device to establish the emergency bearer according to the network behavior information of the first network to establish the emergency bearer, the first terminal device may select the second terminal device and/or the first network to provide the relay service of the emergency service, and if it is determined that the first network does not support the first terminal device to establish the emergency bearer according to the network behavior information of the first network to establish the emergency bearer, the first terminal device may not select the second terminal device and/or the first network to provide the relay service of the emergency service. By the scheme of the embodiment of the application, the first terminal equipment can select the proper terminal equipment and/or network to provide the relay service of the emergency service, so that the success rate of the first terminal equipment for executing the emergency service is improved, and the safety risk is reduced.

Wherein if the first network includes 1 number of networks, the first UE may determine whether to select a relay service for which the network provides emergency services. Or if the first network includes a number of networks greater than 1, the first UE may determine whether to select a relay service in which some or all of the plurality of networks provide emergency services. For example, the first UE may determine whether relay services for the emergency services can be selected for each of the plurality of networks, respectively, or described as being able to select which network or networks of the plurality of networks provide relay services for the emergency services, respectively. The first UE may eventually determine that a relay service for providing emergency services can be selected for some or all of the plurality of networks, or may also determine that a relay service for providing emergency services cannot be selected for all of the plurality of networks. It will be appreciated that if the first network comprises a plurality of networks, the first UE may determine separately for each of the plurality of networks, i.e. may determine separately whether to select a relay service for which the network provides emergency services, rather than determining the first network as a whole. Instead of selecting the first network as a whole, the selection result of the first UE may also be an independent selection of each of the plurality of networks, for example, it may be possible to select some or all of the plurality of networks to provide a relay service for the emergency service.

In an alternative embodiment, the first network is a serving network of the second terminal device, or the first network is a network accessible to a serving cell of the second terminal device. For example, the serving cell of the second terminal device can support access to one or more networks, one of which the first network may be. Or the first network may also be the serving network of the second terminal device.

In an alternative embodiment, the first message is a discovery message or a response message to a connection establishment request message. The first terminal device determines whether to select the second terminal device and/or the first network to provide the relay service of the emergency service according to the first information, which may occur in a discovery procedure (e.g. a discovery procedure between the first terminal device and the second terminal device) or may also occur in a connection establishment procedure (e.g. a connection establishment procedure between the first terminal device and the second terminal device).

In an alternative embodiment, determining whether to select the second terminal device and/or the first network to provide the relay service of the emergency service according to the first information includes: when the first terminal equipment is far-end terminal equipment of a layer 3 type, determining whether to select the second terminal equipment to provide relay service of the emergency service according to the first information; or determining, when the first terminal device is a far-end terminal device of a layer 2 type, whether to select, based on the first information, a relay service for the first network to provide the emergency service (e.g., a network included in the first network is regarded as a candidate network set of the first terminal device, the first terminal device may select a network from the candidate network set to provide the emergency service according to the first information; or when the first terminal equipment is far-end terminal equipment of a layer 2 type, determining whether to select the second terminal equipment and the first network to provide relay service of the emergency service according to the first information. If the first terminal device is a far-end terminal device of the layer 3 type, the first terminal device does not have to be connected to the network, in which case the first terminal device may not have to determine whether to select a relay service for the first network to provide the emergency service. Or even if the first terminal device is a far-end terminal device of the layer 3 type, the first terminal device may not have to determine whether to select a relay service of the first network providing the emergency service, in order to determine whether to use the emergency bearer between the second terminal device and the first network accordingly. If the first terminal device is a far-end terminal device of the layer 2 type, the first terminal device may determine whether to select the second terminal device and the first network to provide a relay service of the emergency service according to the first information. Or if the first terminal device is a far-end terminal device of a layer 2 type, the first terminal device may determine whether to select the relay service of the first network for providing the emergency service according to the first information, and if it is determined that the first network is selected, the first terminal device may further continue to select the relay terminal device within the first network.

In an alternative embodiment, the method further comprises: receiving first configuration information from a first network device, wherein the first configuration information comprises information about whether a second network requires IMS registration to be performed and/or network behavior information for establishing an emergency bearer, the second network comprises a network which is authorized to be accessed by the first terminal device, and the second network comprises the first network; or, receiving second configuration information from a second network device, where the second configuration information includes information about whether a third network requires IMS registration to be performed and/or network behavior information for establishing an emergency bearer, the third network includes a network in which the first terminal device is authorized to use a relay service, and the third network includes the first network; or, the first message includes the first information. The first terminal device obtains the first information in a plurality of ways, and the embodiment of the application is not limited.

In an alternative embodiment, before determining whether to select the second terminal device and/or the first network to provide the relay service of the emergency service according to the first information, the method further comprises: determining that the first network is different from a home network of the first terminal device. If the first network is the same network as the home network of the first terminal device, the first terminal device should be capable of performing emergency services within the first network, so in this case the first terminal device may not have to determine from the first information whether to select the relay service of the emergency services provided by the second terminal device and/or the first network, e.g. the first terminal device may directly select the relay service of the emergency services provided by the second terminal device and/or the first network. And if the first network and the home network of the first terminal device are the same network, the first terminal device may succeed in executing the emergency service in the first network or may fail, so the first terminal device may determine whether to select the second terminal device and/or the first network to provide the relay service of the emergency service according to the first information.

In an alternative embodiment, the first information includes second information, where the second information includes information about whether the first network requires IMS registration to be performed, and determining whether to select the second terminal device and/or the first network to provide a relay service for the emergency service according to the first information includes one or more of the following: selecting a relay service for the second terminal device and/or the first network to provide the emergency service when the second information indicates that the first network does not require IMS registration; or selecting a relay service for providing the emergency service by the second terminal device and/or the first network when the second information indicates that the first network requires to perform IMS registration and the first terminal device has an IMS certificate of the first network; or when the second information indicates that the first network requires to perform IMS registration and the first terminal device does not have an IMS certificate of the first network, not selecting a relay service for providing the emergency service by the second terminal device and/or the first network. When the first information includes the second information, the first terminal device may determine whether to select the second terminal device and/or the relay service of the first network providing the emergency service in the above manner. For example, if the first terminal device is a far-end terminal device of the layer 3 type, the first terminal device may determine whether to select the second terminal device and/or the relay service of the first network providing the emergency service according to the second information.

In an alternative embodiment, the first terminal device has an IMS certificate of the first network, comprising: the first network is a home network of the first terminal equipment; or the first network is different from the home network of the first terminal device, and the first network is a network to which the first terminal device is authorized to access or a network to which the first terminal device is authorized to use a relay service; or the first network is different from the home network of the first terminal device and the first network is capable of verifying the IMS certificate of the first terminal device. Several possible scenarios are given above regarding in what case the first terminal device has an IMS certificate of the first network. In addition, in other scenarios the first terminal device may also have an IMS certificate of the first network.

In an alternative embodiment, the first information includes third information, where the third information includes network behavior information of the first network to establish an emergency bearer, and determining, according to the first information, whether to select the second terminal device and/or the first network to provide a relay service of the emergency service includes one or more of the following: selecting a relay service of the second terminal device and/or the first network to provide the emergency service when it is determined that an emergency bearer can be established in the first network according to the third information; or when it is determined that the emergency bearer cannot be established in the first network according to the third information, not selecting the relay service of the emergency service provided by the second terminal device and/or the first network. When the first information includes the third information, the first terminal device may determine whether to select the second terminal device and/or the relay service of the first network providing the emergency service in the above manner.

In an alternative embodiment, the first information includes second information and third information, the second information includes information whether the first network requires IMS registration, the third information includes network behavior information of the first network to establish an emergency bearer, and determining whether to select the second terminal device and/or the first network to provide a relay service of the emergency service according to the first information includes one or more of the following: selecting a relay service of the second terminal device and/or the first network to provide the emergency service when the second information indicates that the first network does not require IMS registration, and the emergency bearer can be established in the first network according to the third information; or when the second information indicates that the first network does not require to execute IMS registration, and determines that emergency bearing can not be established in the first network according to the third information, the second terminal equipment and/or the first network are/is not selected to provide relay service of the emergency service; or when the second information indicates that the first network requires to execute IMS registration, the first terminal equipment has an IMS certificate of the first network, and the second terminal equipment and/or the first network are/is selected to provide relay service of the emergency service when the emergency bearer can be established in the first network according to the third information; or when the second information indicates that the first network requires to execute IMS registration and the first terminal equipment has an IMS certificate of the first network, and the first terminal equipment and/or the first network are/is not selected to provide relay service of the emergency service when the first network can not establish emergency bearer according to the third information; or when the second information indicates that the first network requires to execute IMS registration and the first terminal equipment does not have IMS certificate of the first network, and determines that emergency bearing can be established in the first network according to the third information, the relay service of the emergency service provided by the second terminal equipment and/or the first network is not selected; or when the second information indicates that the first network requires to execute IMS registration and the first terminal equipment does not have IMS certificate of the first network, and the emergency bearer can not be established in the first network according to the third information, the relay service of the emergency service provided by the second terminal equipment and/or the first network is not selected. When the first information includes the second information and the third information, the first terminal device may determine whether to select the relay service of the emergency service provided by the second terminal device and/or the first network in the above manner. In short, if the first terminal device satisfies the second information and the third information, the first terminal device may select the relay service for providing the emergency service by the second terminal device and/or the first network, and if the first terminal device does not satisfy the second information and/or the third information, the first terminal device may not select the relay service for providing the emergency service by the second terminal device and/or the first network. And the selection result of the first terminal equipment is more accurate by combining the second information and the third information to judge.

In an alternative embodiment, the network behavior of the first network to establish emergency bearers includes one or more of: only the terminal devices having a valid subscription and successfully registering the network are allowed to establish an emergency bearer, only the terminal devices having a valid subscription are allowed to establish an emergency bearer, only the terminal devices having identification information are allowed to establish an emergency bearer, or all the terminal devices are allowed to establish an emergency bearer.

In an alternative embodiment, determining that an emergency bearer can be established in the first network according to the third information includes one or more of: determining that an emergency bearer can be established on the first network when the third information indicates that the network behavior of the first network includes allowing all terminal devices to establish an emergency bearer; or when the third information indicates that the network behavior of the first network includes allowing only a terminal device having identification information to establish an emergency bearer, and the first terminal device has identification information, determining that an emergency bearer can be established in the first network; or when the third information indicates that the network behavior of the first network includes allowing only a terminal device having a valid subscription to establish an emergency bearer, and the first terminal device has a valid subscription to the first network, determining that an emergency bearer can be established on the first network; or when the third information indicates that the network behavior of the first network includes only allowing a terminal device having a valid subscription and successfully registering with a network to establish an emergency bearer, and the first terminal device has the valid subscription of the first network, and the first terminal device is not in a limited service state, determining that the emergency bearer can be established in the first network.

In an alternative embodiment, the first terminal device has an active subscription of the first network, including: the first network is a home network of the first terminal equipment; or the first network is different from the home network of the first terminal device, and the first network is a network to which the first terminal device is authorized to access or a network to which the first terminal device is authorized to use a relay service. Several possible scenarios are given above regarding in what case the first terminal device has an active subscription to the first network. In addition, the first terminal device may have a valid subscription to the first network in other scenarios.

In an alternative embodiment, the first message is used for indicating a relay service providing emergency services, and includes: the first message includes a first service code, where the first service code is a service code corresponding to the emergency service, for example, the first service code is an emergency RSC.

In a second aspect, a second communication method is provided, which may be performed by a terminal device, or by another device comprising the functionality of the terminal device, or by a chip system (or chip) or other functional module capable of implementing the functionality of the terminal device, the chip system or functional module being for example provided in the terminal device. The terminal device is for example a second terminal device. The method comprises the following steps: acquiring first information, wherein the first information comprises information whether a first network requires IMS registration to be executed or not, and/or network behavior information of the first network for establishing emergency bearing, and the first network is a service network of the second terminal equipment; and sending a first message to the first terminal equipment, wherein the first message comprises the first information, and the first message is also used for indicating a relay service for providing emergency services.

In an alternative embodiment, the first network is a serving network of the second terminal device, or the first network is a network accessible to a serving cell of the second terminal device.

In an alternative embodiment, the first message is a discovery message or a response message to a connection establishment request message.

In an alternative embodiment, obtaining the first information includes: receiving third configuration information from a fourth network device, wherein the third configuration information comprises information about whether the fourth network requires IMS registration to be performed and/or network behavior information for establishing an emergency bearer, the fourth network comprises a network which the second terminal device is authorized to access, and the fourth network comprises the first network; or, receiving fourth configuration information from a fifth network device, where the fourth configuration information includes information about whether a fifth network requires IMS registration to be performed and/or network behavior information for establishing an emergency bearer, the fifth network includes a network in which the second terminal device is authorized to provide a relay service, and the fifth network includes the first network; or, receiving the first information from a third network device.

In an alternative embodiment, receiving the first information from a third network device includes: the first information from the third network device is received during or after registration with the first network.

In an alternative embodiment, before sending the first discovery message to the first terminal device, the method further comprises: and receiving a second message from the first terminal equipment, wherein the second message comprises a second service code, and the second service code is used for requesting relay service for providing emergency services.

In an alternative embodiment, the second terminal device is a layer 3 type relay terminal device or a layer 2 type relay terminal device.

In an alternative embodiment, when the second terminal device is a layer 3 type relay terminal device, the first information includes information whether the first network requires IMS registration to be performed, and does not include network behavior information that the first network establishes an emergency bearer; or when the second terminal device is a layer 2 type relay terminal device, the first information includes information whether the first network requires IMS registration to be performed, and includes network behavior information that the first network establishes an emergency bearer.

In an alternative embodiment, the first message is used for indicating a relay service providing emergency services, and includes: the first message comprises a first service code, and the first service code is a service code corresponding to the emergency service.

Regarding the technical effects brought about by the second aspect or various alternative embodiments, reference may be made to the description of the technical effects of the first aspect or corresponding embodiments.

In a third aspect, a third communication method is provided, which may be performed by a terminal device, or by another device comprising the functionality of the terminal device, or by a chip system (or chip) or other functional module capable of implementing the functionality of the terminal device, the chip system or functional module being for example provided in the terminal device. The terminal device is for example a second terminal device. The method comprises the following steps: receiving a first message from a first terminal device, wherein the first message is used for requesting relay service of emergency service; determining whether to provide relay service of the emergency service for the first terminal equipment according to first information, wherein the first information comprises information whether the first network requires to execute IMS registration or not and/or network behavior information of the first network for establishing emergency bearing; and sending a second message to the first terminal equipment, wherein the second message is used for indicating a relay service for providing the emergency service. In the embodiment of the application, the first terminal equipment can select the proper terminal equipment and/or network to provide the relay service of the emergency service through the judgment of the second terminal equipment, so that the success rate of the first terminal equipment for executing the emergency service is improved, and the safety risk is reduced. It can be seen that, regarding whether the first terminal device can select a certain terminal device and/or network to provide the relay service of the emergency service, the first terminal device may determine the relay service by itself, or may determine the relay service by other terminal devices (e.g., the second terminal device), which is flexible.

In an alternative embodiment, the first message further comprises information of the home network of the first terminal device. The first terminal device may inform the second terminal device of the home network of the first terminal device to assist the second terminal device in determining whether to provide relay services for the emergency services for the first terminal device.

In an alternative embodiment, the first message further comprises identification information of the first terminal device. The first terminal device may inform the second terminal device of the identification information of the first terminal device to assist the second terminal device in determining whether to provide the relay service of the emergency service for the first terminal device.

In an alternative embodiment, before determining whether to provide the relay service of the emergency service for the first terminal device according to the first information, the method further includes: determining that the home network of the first terminal device is different from the first network. If the home network of the first terminal device is the same network as the first network, the first terminal device can perform the emergency service in the first network, so that the second terminal device may not need to determine whether to provide the relay service of the emergency service for the first terminal device according to the first information, for example, the second terminal device determines the relay service capable of providing the emergency service for the first terminal device. And if the home network of the first terminal device is a different network from the first network, the first terminal device may succeed in executing the emergency service in the first network or may fail, so the second terminal device may determine whether to provide the relay service of the emergency service for the first terminal device according to the first information.

In an alternative embodiment, the first information includes second information, where the second information includes information about whether the first network requires IMS registration to be performed, and determining whether to provide the first terminal device with a relay service of the emergency service according to the first information includes one or more of the following: determining to provide the relay service of the emergency service for the first terminal device when the second information indicates that the first network does not require IMS registration; or when the second information indicates that the first network requires to execute IMS registration, determining to provide relay service of the emergency service for the first terminal equipment; or when the second information indicates that the first network requires to execute IMS registration, determining that relay service of the emergency service is not provided for the first terminal equipment. When the first information includes the second information, the second terminal device may determine whether to provide the relay service of the emergency service for the first terminal device in the above manner.

In an alternative embodiment, after determining that the relay service of the emergency service is not provided for the first terminal device, the method further comprises: and sending a third message to the first terminal equipment, wherein the third message is used for rejecting the relay service providing the emergency service. If the second terminal device does not provide the first terminal device with a relay service for the emergency service, the second terminal device may also send a third message to the first terminal device, which may be able to determine that it is rejected by the second terminal device, e.g. the first terminal device may take corresponding measures in time, e.g. re-search for a relay terminal device, etc.

In an alternative embodiment, the third message includes a first cause value for indicating that the first network requires IMS registration to be performed. For example, the second terminal device refuses the first terminal device because the first network requires performing an IMS registration, the third message may comprise the first cause value.

In an alternative embodiment, the third message includes a second cause value for indicating that the first network does not allow all terminal devices to establish an emergency bearer. For example, if the second terminal device does not obtain the identification information of the first terminal device, and the first network does not allow all terminal devices to establish the emergency bearer, the second terminal device may reject the first terminal device, and the third message may include the second cause value. By including the corresponding cause value in the third message, the first terminal device can be made to specify the reason for the rejection.

In an alternative embodiment, the method further comprises: receiving third configuration information from fourth network equipment, wherein the first configuration information comprises information of whether the fourth network requires IMS registration to be executed and/or network behavior information for establishing emergency bearer, the fourth network comprises a network which the second terminal equipment is authorized to access, and the fourth network comprises the first network; or, receiving fourth configuration information from a fifth network device, where the fourth configuration information includes information about whether the fifth network requires IMS registration to be performed and/or network behavior information for establishing an emergency bearer, the fifth network includes a network in which the second terminal device is authorized to act as a relay terminal device, and the fifth network includes the first network; or, receiving the first information from a third network device. The second terminal device may obtain the first information in various ways, which is not limited.

In an alternative embodiment, the first message is a discovery request message, or a connection establishment request message. The second terminal device determines whether to provide the relay service of the emergency service for the first terminal device according to the first information, which may occur in a discovery process between the first terminal device and the second terminal device, or may occur in a connection establishment process between the first terminal device and the second terminal device.

In an alternative embodiment, the first message is the discovery request message, and the second message is a discovery response message or a discovery announce message; or the first message is the connection establishment request message, and the second message is a connection establishment response message; or the first message is the connection establishment request message, and the third message is a connection establishment rejection message.

In a fourth aspect, a fourth communication method is provided, which may be performed by a terminal device, or by another device comprising the functionality of the terminal device, or by a chip system (or chip) or other functional module capable of implementing the functionality of the terminal device, the chip system or functional module being for example provided in the terminal device. The terminal device is for example a second terminal device. The method comprises the following steps: transmitting a first message for requesting a relay service of an emergency service; a second message or a third message from the second terminal device is received, the second message being used to indicate a relay service providing the emergency service, and the third message being used to reject the relay service providing the emergency service.

In an alternative embodiment, the first message further comprises information of the home network of the first terminal device.

In an alternative embodiment, the first message further comprises identification information of the first terminal device.

In an alternative embodiment, the third message includes a first cause value for indicating that the first network requires IMS registration to be performed.

In an alternative embodiment, the third message includes a second cause value for indicating that the first network does not allow all terminal devices to establish an emergency bearer.

In an alternative embodiment, after receiving the third message from the second terminal device, the method further comprises: and not selecting the relay service of the second terminal equipment for executing the emergency service and/or not selecting the service network of the second terminal equipment.

In an alternative embodiment, the first message is a discovery request message, or a connection establishment request message.

Regarding the technical effects brought about by the fourth aspect or various alternative embodiments, reference may be made to the description of the technical effects of the third aspect or corresponding embodiments.

In a fifth aspect, a fifth communication method is provided, which may be performed by a terminal device, or by another device comprising the functionality of the terminal device, or by a chip system (or chip) or other functional module, which is capable of implementing the functionality of the terminal device, the chip system or functional module being provided in the terminal device, for example. The method comprises the following steps: determining that the home network of the terminal equipment cannot be searched; the network is selected according to first information comprising information whether at least one network requires performing IMS registration and/or comprising network behavior information for the at least one network to establish an emergency bearer. In the embodiment of the application, the terminal equipment can select a proper network, so that the success rate of the terminal equipment for executing the emergency service is improved, and the safety risk is reduced. And the terminal equipment can select to access the proper network as much as possible in the network selection stage, thereby reducing the probability that the emergency service cannot be initiated due to the improper network access or reducing the time delay of network reselection due to the improper network access.

In an alternative embodiment, the method further comprises: first configuration information is received from a first network device, wherein the first configuration information comprises information whether the at least one network requires IMS registration and/or network behavior information for establishing an emergency bearer, and the at least one network is a network to which the terminal device is authorized to access. The terminal device may obtain the first information in a number of ways, an alternative way being given here.

In an alternative embodiment, the first information includes second information, the second information including information whether the at least one network requires IMS registration to be performed, selecting a network according to the first information, including: selecting the first network when the second information indicates that the first network does not require IMS registration; or selecting the first network when the second information indicates that the first network requires to perform IMS registration and the terminal device has an IMS certificate of the first network; or when the second information indicates that the first network requires to perform IMS registration and the terminal device does not have an IMS certificate of the first network, the first network is not selected. Wherein the first network belongs to the at least one network. When the first information includes the second information, the terminal device may select the network in the above manner.

In an alternative embodiment, the terminal device has an IMS certificate of the first network, comprising: the first network is different from a home network of the terminal equipment, and the first network is a network to which the terminal equipment is authorized to access; or the first network is different from the home network of the terminal device and the first network is capable of verifying the IMS certificate of the terminal device.

In an alternative embodiment, the first information includes third information, the third information includes network behavior information of the at least one network to establish an emergency bearer, and selecting a network according to the first information includes: selecting a first network when it is determined that an emergency bearer can be established in the first network according to the third information; or when it is determined that the emergency bearer cannot be established in the first network according to the third information, the first network is not selected. Wherein the first network belongs to the at least one network.

In an alternative embodiment, the first information includes second information and third information, the second information includes information whether the at least one network requires IMS registration to be performed, the third information includes network behavior information for the at least one network to establish an emergency bearer, and selecting a network according to the first information includes one or more of: selecting the first network when the second information indicates that the first network does not require IMS registration, and the first network can establish an emergency bearer according to the third information; or when the second information indicates that the first network does not require IMS registration, and determines that emergency bearing cannot be established in the first network according to the third information, the first network is not selected; or when the second information indicates that the first network requires to execute IMS registration, the terminal equipment has an IMS certificate of the first network, and the first network is selected according to the third information when the emergency bearing can be established in the first network; or when the second information indicates that the first network requires to execute IMS registration and the terminal equipment has an IMS certificate of the first network, and according to the third information, determining that emergency bearing cannot be established in the first network, not selecting the first network; or when the second information indicates that the first network requires to execute IMS registration and the terminal equipment does not have IMS certificate of the first network, and according to the third information, the first network is not selected when the emergency bearer can be established in the first network; or when the second information indicates that the first network requires to execute IMS registration and the terminal equipment does not have IMS certificate of the first network, and the first network is not selected according to the third information, if the emergency bearer can not be established in the first network.

In an alternative embodiment, the network behavior of a first network of the at least one network to establish an emergency bearer includes one or more of: only the terminal devices having a valid subscription and successfully registering the network are allowed to establish an emergency bearer, only the terminal devices having a valid subscription are allowed to establish an emergency bearer, only the terminal devices having identification information are allowed to establish an emergency bearer, or all the terminal devices are allowed to establish an emergency bearer.

In an alternative embodiment, determining that an emergency bearer can be established in the first network according to the third information includes one or more of: determining that an emergency bearer can be established on the first network when the third information indicates that the network behavior of the first network includes allowing all terminal devices to establish an emergency bearer; or when the third information indicates that the network behavior of the first network includes allowing only a terminal device having identification information to establish an emergency bearer, and the terminal device has identification information, determining that an emergency bearer can be established in the first network; or when the third information indicates that the network behavior of the first network includes allowing only a terminal device having a valid subscription to establish an emergency bearer, and the terminal device has a valid subscription to the first network, determining that an emergency bearer can be established on the first network; or when the third information indicates that the network behavior of the first network includes only allowing a terminal device having a valid subscription and successfully registering with a network to establish an emergency bearer, and the terminal device has a valid subscription of the first network, and the terminal device is not in a limited service state, determining that an emergency bearer can be established in the first network.

In an alternative embodiment, the terminal device has an active subscription of the first network, including: the first network is different from a home network of the terminal device, and the first network is a network to which the terminal device is authorized to access.

Regarding the technical effects brought about by the fifth aspect or various alternative embodiments, reference may be made to the description of the technical effects of the first aspect or corresponding embodiments.

In a sixth aspect, a sixth communication method is provided, which may be performed by a terminal device, or by another device comprising the functionality of the terminal device, or by a chip system (or chip) or other functional module, which is capable of implementing the functionality of the terminal device, the chip system or functional module being provided in the terminal device, for example. The method comprises the following steps: receiving first information from a first network in the process of registering to the first network, wherein the first information comprises information whether the first network requires IMS registration to be executed or not and/or network behavior information for establishing emergency bearing by the first network; and determining whether to reselect a network according to the first information. In the embodiment of the application, the terminal equipment can select a proper network, so that the success rate of the terminal equipment for executing the emergency service is improved, and the safety risk is reduced.

In an alternative embodiment, the first information includes second information, the second information includes information whether the first network requires IMS registration, and determining whether to reselect a network according to the first information includes: when the second information indicates that the first network does not require IMS registration, not reselecting a network; or when the second information indicates that the first network requires to perform IMS registration and the terminal device has an IMS certificate of the first network, not reselecting the network; or reselecting a network when the second information indicates that the first network requires IMS registration to be performed and the terminal device does not have an IMS certificate of the first network.

In an alternative embodiment, the terminal device has an IMS certificate of the first network, comprising: the first network is a home network of the terminal equipment; or the first network is different from the home network of the terminal equipment, and the first network is a network to which the terminal equipment is authorized to access; or the first network is different from the home network of the terminal device and the first network is capable of verifying the IMS certificate of the terminal device.

In an alternative embodiment, the first information includes third information, the third information includes network behavior information of the first network for establishing an emergency bearer, and determining whether to reselect a network according to the first information includes: when it is determined that an emergency bearer can be established in the first network according to the third information, not reselecting a network; or reselecting a network when it is determined that an emergency bearer cannot be established in the first network according to the third information.

In an alternative embodiment, the first information includes second information and third information, the second information includes information whether the first network requires IMS registration, the third information includes network behavior information of the first network to establish an emergency bearer, and determining whether to reselect a network according to the first information includes: when the second information indicates that the first network does not require IMS registration, and according to the third information, determining that emergency bearing can be established in the first network, not reselecting the network; or reselecting a network when the second information indicates that the first network does not require IMS registration, and determines that emergency bearing cannot be established in the first network according to the third information; or when the second information indicates that the first network requires to execute IMS registration and the terminal equipment has an IMS certificate of the first network, and according to the third information, determining that emergency bearing can be established in the first network, not reselecting the network; or when the second information indicates that the first network requires to execute IMS registration and the terminal equipment has an IMS certificate of the first network, and the first network cannot establish emergency bearing according to the third information, reselecting the network; or when the second information indicates that the first network requires to execute IMS registration and the terminal equipment does not have IMS certificate of the first network, and the network is reselected according to the third information when the emergency bearing can be established in the first network; or reselecting a network when the second information indicates that the first network requires to perform IMS registration and the terminal equipment does not have IMS certificate of the first network and determines that emergency bearing can not be established in the first network according to the third information.

In an alternative embodiment, the terminal device has an active subscription of the first network, including: the first network is a home network of the terminal equipment; or the first network is different from the home network of the terminal device and is a network to which the terminal device is authorized to access.

Regarding the technical effects brought about by the sixth aspect or various alternative embodiments, reference may be made to the description of the technical effects of the first aspect or corresponding embodiments.

In a seventh aspect, a communication device is provided. The communication apparatus may be the first terminal device of any one of the first to fourth aspects. The communication device has the function of the first terminal device. The communication means are for example a first terminal device, or a larger device comprising the first terminal device, or a functional module in the first terminal device, such as a baseband device or a system on chip, etc. In an alternative implementation, the communication device includes a baseband device and a radio frequency device. In another alternative implementation, the communication device includes a processing unit (sometimes also referred to as a processing module) and a transceiver unit (sometimes also referred to as a transceiver module). The transceiver unit can realize a transmission function and a reception function, and may be referred to as a transmission unit (sometimes referred to as a transmission module) when the transceiver unit realizes the transmission function, and may be referred to as a reception unit (sometimes referred to as a reception module) when the transceiver unit realizes the reception function. The transmitting unit and the receiving unit may be the same functional module, which is called a transceiver unit, and which can implement a transmitting function and a receiving function; or the transmitting unit and the receiving unit may be different functional modules, and the transceiver unit is a generic term for these functional modules.

In an alternative embodiment, the transceiver unit (or the receiving unit) is configured to receive a first message from a second terminal device, where the first message is used to indicate a relay service that provides an emergency service; the processing unit is configured to determine whether to select the second terminal device and/or the first network to provide the relay service of the emergency service according to first information, where the first information includes information whether the first network requires IMS registration to be performed, and/or includes network behavior information that the first network establishes an emergency bearer.

In an alternative embodiment, the transceiver unit (or the transmitting unit) is configured to transmit a first message, where the first message is used for requesting a relay service of an emergency service; the transceiver unit (or the receiving unit) is configured to receive a second message or a third message from a second terminal device, where the second message is used to indicate a relay service providing an emergency service, and the third message is used to reject the relay service providing the emergency service.

In an alternative embodiment, the communication device further comprises a storage unit (sometimes also referred to as a storage module), the processing unit being configured to be coupled to the storage unit and execute a program or instructions in the storage unit, to enable the communication device to perform the functions of the first terminal device according to any one of the first to fourth aspects.

In an eighth aspect, a communication device is provided. The communication apparatus may be the second terminal device of any one of the first to fourth aspects. The communication device has the function of the second terminal device. The communication means is for example a second terminal device, or a larger device comprising the second terminal device, or a functional module in the second terminal device, such as a baseband device or a system on chip, etc. In an alternative implementation, the communication device includes a baseband device and a radio frequency device. In another alternative implementation, the communication device includes a processing unit (sometimes also referred to as a processing module) and a transceiver unit (sometimes also referred to as a transceiver module). Reference may be made to the description of the seventh aspect for implementation of the transceiver unit.

In an optional implementation manner, the processing unit is configured to obtain first information, where the first information includes information about whether a first network requires IMS registration to be performed, and/or network behavior information that the first network establishes an emergency bearer, where the first network is a serving network of the second terminal device; the transceiver unit (or the transmitting unit) is configured to transmit a first message to a first terminal device, where the first message includes the first information, and the first message is further configured to indicate a relay service that provides an emergency service.

In an alternative embodiment, the transceiver unit (or the receiving unit) is configured to receive a first message from a first terminal device, where the first message is used to request a relay service of an emergency service; the processing unit is configured to determine whether to provide a relay service of the emergency service for the first terminal device according to first information, where the first information includes information about whether the first network requires to perform IMS registration, and/or includes network behavior information about whether the first network establishes an emergency bearer; the transceiver unit (or the transmitting unit) is configured to transmit a second message to the first terminal device, where the second message is used to indicate a relay service that provides the emergency service.

In an alternative embodiment, the communication device further comprises a storage unit (sometimes also referred to as a storage module), the processing unit being configured to be coupled to the storage unit and execute a program or instructions in the storage unit, to enable the communication device to perform the functions of the second terminal device according to any one of the first to fourth aspects.

In a ninth aspect, a communication apparatus is provided. The communication apparatus may be the terminal device of any one of the fifth to sixth aspects. The communication device has the functions of the terminal device. The communication means are for example terminal devices, or larger devices comprising terminal devices, or functional modules in terminal devices, such as baseband means or chip systems etc. In an alternative implementation, the communication device includes a baseband device and a radio frequency device. In another alternative implementation, the communication device includes a processing unit (sometimes also referred to as a processing module) and a transceiver unit (sometimes also referred to as a transceiver module). Reference may be made to the description of the seventh aspect for implementation of the transceiver unit.

In an alternative embodiment, the processing unit is configured to obtain a determination that the home network of the terminal device cannot be searched; the processing unit is further configured to select a network according to first information, where the first information includes information whether at least one network requires IMS registration to be performed, and/or includes network behavior information that the at least one network establishes an emergency bearer.

In an alternative embodiment, the transceiver unit (or the receiving unit) is configured to receive, during registration with a first network, first information from the first network, where the first information includes information about whether the first network requires IMS registration to be performed, and/or includes network behavior information that the first network establishes an emergency bearer; the processing unit is used for determining whether to reselect a network according to the first information.

In an alternative embodiment, the communication device further comprises a storage unit (sometimes also referred to as a storage module), the processing unit being configured to be coupled to the storage unit and execute a program or instructions in the storage unit, to enable the communication device to perform the functions of the terminal apparatus according to any one of the fifth to sixth aspects.

In a tenth aspect, a communication apparatus is provided, which may be the first terminal device, or a chip system for use in the first terminal device. The communication device comprises a communication interface and a processor, and optionally a memory. Wherein the memory is configured to store a computer program, and the processor is coupled to the memory and the communication interface, and when the processor reads the computer program or instructions, the processor causes the communication device to perform the method performed by the first terminal device in the above aspects.

In an eleventh aspect, a communication apparatus is provided, which may be an access network device, or a chip system for use in an access network device. The communication device comprises a communication interface and a processor, and optionally a memory. Wherein the memory is configured to store a computer program, and the processor is coupled to the memory and the communication interface, and wherein the processor, when reading said computer program or instructions, causes the communication device to perform the method performed by the second terminal device in the above aspects.

In a twelfth aspect, a communication apparatus is provided, which may be an access network device, or a chip system for use in an access network device. The communication device comprises a communication interface and a processor, and optionally a memory. Wherein the memory is configured to store a computer program, and the processor is coupled to the memory and the communication interface, and when the processor reads the computer program or instructions, the processor causes the communication device to perform the method performed by the terminal device in the above aspects.

A thirteenth aspect provides a communication system comprising a first terminal device for performing the method performed by the first terminal device according to any of the first to fourth aspects, and a second terminal device for performing the method performed by the second terminal device according to any of the first to fourth aspects. For example, the first terminal device may be implemented by the communication apparatus of the seventh aspect or the tenth aspect; the second terminal device may be implemented by the communication apparatus according to the eighth or eleventh aspect.

In a fourteenth aspect, there is provided a computer readable storage medium storing a computer program or instructions which, when executed, cause a method performed by a first or second terminal device or terminal device of the above aspects to be carried out.

In a fifteenth aspect, there is provided a computer program product containing instructions which, when run on a computer, cause the method of the above aspects to be carried out.

In a sixteenth aspect, there is provided a chip system comprising a processor and an interface, the processor being operable to invoke and execute instructions from the interface to cause the chip system to implement the method of the above aspects.

Drawings

Fig. 1 is a flow of a UE making an emergency call in a 4G/5G dependent IMS network;

FIG. 2 is a schematic diagram of a 5G network architecture;

FIG. 3 is a schematic diagram of a layer 3 relay architecture;

FIG. 4 is a schematic diagram of a layer 2 relay architecture;

FIG. 5A is a discovery process for model A;

FIG. 5B is a discovery process for model B;

FIG. 5C is a process of establishing a connection between a remote UE and a relay UE;

FIGS. 6-9 are flowcharts of several communication methods according to embodiments of the present application;

FIG. 10 is a schematic diagram of an apparatus according to an embodiment of the present application;

Fig. 11 is a schematic view of yet another apparatus according to an embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application more apparent, the embodiments of the present application will be described in further detail with reference to the accompanying drawings.

In the embodiments of the present application, the number of nouns, unless otherwise indicated, means "a singular noun or a plural noun", i.e. "one or more". "at least one" means one or more, and "a plurality" means two or more. "and/or", describes an association relationship of an association object, and indicates that there may be three relationships, for example, a and/or B, and may indicate: a alone, a and B together, and B alone, wherein a, B may be singular or plural. The character "/" generally indicates that the context-dependent object is an "or" relationship. For example, A/B, means: a or B. "at least one of" or the like means any combination of these items, including any combination of single item(s) or plural items(s). For example, at least one (one) of a, b, or c, represents: a, b, c, a and b, a and c, b and c, or a and b and c, wherein a, b, c may be single or plural.

The ordinal terms such as "first," "second," and the like in the embodiments of the present application are used for distinguishing a plurality of objects, and are not used for limiting the size, content, sequence, timing, priority, importance, and the like of the plurality of objects. In addition, the numbers of the steps in the embodiments described in the embodiments of the present application are only for distinguishing different steps, and are not used for limiting the sequence of the steps. For example, S601 may occur before S602, or may occur after S602, or may also occur simultaneously with S602.

In the following, some terms or concepts in the embodiments of the present application are explained for easy understanding by those skilled in the art.

(1) In the embodiment of the application, the terminal device is a device with a wireless transceiver function, and may be a fixed device, a mobile device, a handheld device (such as a mobile phone), a wearable device, a vehicle-mounted device, or a wireless apparatus (such as a communication module, a modem, or a chip system) built in the device. The terminal device is used for connecting people, objects, machines and the like, and can be widely used in various scenes, including but not limited to the following scenes: cellular communication, device-to-device (D2D), V2X, machine-to-machine/machine-like communication (machine-to-machine/machine-type communications, M2M/MTC), internet of things (internet of things, ioT), virtual Reality (VR), augmented reality (augmented reality, AR), industrial control (industrial control), unmanned driving (SELF DRIVING), remote medical (remote media), smart grid (SMART GRID), smart furniture, smart office, smart wear (e.g., smart watch, smart bracelet, smart helmet or smart glasses, etc.), smart transportation, smart city (SMART CITY), end devices for scenes such as drones, robots, etc. The terminal device may sometimes be referred to as a UE, a terminal, an access station, a UE station, a client device (customer premise equipment, CPE), a remote station, a wireless communication device, or a user equipment, among others. For convenience of description, in the embodiment of the present application, a UE is taken as an example for illustrating a terminal device.

(2) The network device in the embodiment of the application comprises an access network device and/or a core network device. The access network equipment is equipment with a wireless receiving and transmitting function and is used for communicating with the terminal equipment. The access network devices include, but are not limited to, base stations (base transceiver stations (base transceiver station, BTS), node B, eNodeB/eNB, or gNodeB/gNB), transceiver points (transmission reception point, TRP), base stations for subsequent evolution of the third generation partnership project (3rd generation partnership project,3GPP), access nodes in wireless fidelity (WIRELESS FIDELITY, wi-Fi) systems, wireless relay nodes, wireless backhaul nodes, and the like. The base station may be: macro base station, micro base station, pico base station, small station, relay station, etc. Multiple base stations may support networks of the same access technology or may support networks of different access technologies. A base station may comprise one or more co-sited or non-co-sited transmission reception points. The access network device may also be a radio controller, a centralized unit (centralized unit, CU), and/or a Distributed Unit (DU) in the context of a cloud radio access network (cloud radio access network, CRAN). The access network device may also be a server or the like. For example, the network device in the vehicle-to-everything (vehicle to everything, V2X) technology may be a Road Side Unit (RSU). The following describes an access network device using a base station as an example. The base station may communicate with the terminal device or may communicate with the terminal device through the relay station. A terminal device may communicate with multiple base stations in different access technologies. The core network device is used for realizing the functions of mobile management, data processing, session management, policy and charging, etc. The names of devices implementing the core network function in the systems of different access technologies may be different, and the embodiment of the present application is not limited to this. Taking the fifth generation (the 5th generation,5G) mobile communication system as an example, the core network device includes: access and mobility management functions (ACCESS AND mobility management function, AMF), session management functions (session management function, SMF), policy control functions (policy control function, PCF), or user plane functions (user plane function, UPF), etc.

In the embodiment of the present application, the communication device for implementing the function of the network device may be a network device, or may be a device capable of supporting the network device to implement the function, for example, a chip system, and the device may be installed in the network device. In the technical solution provided in the embodiment of the present application, the device for implementing the function of the network device is exemplified by the network device, and the technical solution provided in the embodiment of the present application is described.

The technical features related to the embodiments of the present application are described below.

Referring to fig. 1, a procedure for a UE to place an emergency call in a 4G/5G dependent IMS network is shown.

S101, the UE detects an emergency session request (DETECT EMERGENCY session request). It is understood that the UE determines that there is a need to initiate an emergency session.

S102, UE capability and resource verification (UE capability and resource validation). It is understood that both UE and IMS are capable of supporting emergency sessions.

S103, bearing registration (bearer registration). Or may also be referred to as emergency registration. In this step, the UE may initiate an emergency registration procedure with the core network. An IP-connected access network (IP-connectivity access network, CAN) such as in fig. 1 CAN be understood as a core network.

S104, bearing a resource request (bearer resource request). A bearer establishment procedure can be understood. In this step, the UE establishes an emergency bearer with the core network.

S105, proxy-call session control function, P-CSCF discovery process. The P-CSCF is a network element in the IMS network, and the core network may discover the P-CSCF and inform the UE of the address of the P-CSCF so that the UE can communicate with the P-CSCF.

S106, IMS registration (IMS registration). In this procedure, the UE registers with the IMS network, e.g. the UE may register with the P-CSCF.

S107, an emergency session (bearer resource) is established (establish emergency session (and bearer resource)). In this step, the UE establishes an emergency session with the P-CSCF for carrying the emergency call, so that a network element within the IMS, such as the P-CSCF, can transmit the emergency call of the UE to the called party, such as an emergency centre (EMERGENCY CENTER) or Public Safety Answering Point (PSAP), etc.

S103 and S104 above may be regarded as a procedure for establishing an emergency bearer at the core network; s106 and S107 may be regarded as another procedure which may be used to establish an emergency session at the IMS. In both procedures, the network may reject the UE's request.

For example, when the core network establishes an emergency bearer, the core network may determine whether to accept the UE's request according to a corresponding network behavior, e.g., the network is determined according to an operator policy, which may be understood as whether to accept the UE's rules for emergency registration and/or establishment of an emergency bearer. For example, the network behavior of a network may include any one or more of the following:

Act a, allows only valid UEs to establish emergency bearers, or describes that only UEs with valid subscriptions and successfully registered with the network are allowed to establish emergency bearers.

For action a it is understood that the core network only allows UEs with a valid subscription and successfully registered with the network to establish emergency bearers or to make emergency registrations. If the identification information provided by the UE can be successfully verified by the core network, the UE is indicated to have a valid subscription. The identification information is, for example, an identification of a communication module such as a subscriber identity module (subscriber identity module, SIM) or an embedded subscriber identity module (embedded-subscriber identity module, eSIM) used by the UE, and the identification information includes, for example, an international mobile subscriber identity (international mobile subscriber identity, IMSI) or a subscriber permanent identity (subscription PERMANENT IDENTIFIER, SUPI), and may also include a temporary identity such as a globally unique temporary UE identity (globally unique temporary UE identity, GUTI), or a 5G-GUTI.

Behavior a requires that the UE cannot be in the limited service state (LIMITED SERVICE STATE), that is, the UE in the limited service state (LIMITED SERVICE STATE) does not satisfy behavior a. If the network behavior supported by the core network is behavior a, the core network may reject the emergency registration request or the request for establishing an emergency bearer for the UE in a limited service state. The UE in the limited service state includes, for example, UE with arrears, UE without SIM/USIM/eSIM card, UE unable to find a suitable cell to camp on, or UE unable to normally access the network due to other reasons when receiving a network response indicating that the UE is illegal. It can be appreciated that the restricted service state is relative to the normal service state, the UE in the normal service state can normally initiate traffic, and the UE in the restricted service state can only attempt to initiate emergency traffic.

Act B, allows only authenticated UEs to establish emergency bearers, or describes that only UEs with valid subscriptions are allowed to establish emergency bearers.

For action B it can be understood that the core network only allows UEs with valid subscriptions to establish emergency bearers. If the core network supports action B, the core network can accept the UE's emergency registration request or request to establish an emergency bearer as long as the UE has a valid subscription even though the UE is in a restricted service state. If one network supports only action B and not others, then the network may reject the UE's emergency registration request or request to establish an emergency bearer if the UE does not have a valid subscription.

Act C, only allowing the UE with identification information to establish an emergency bearer.

As for the action C, it can be understood that as long as the UE can provide the identification information, whether the core network can verify the identification information successfully or not, the core network can accept the request of emergency registration of the UE or the request of establishing the emergency bearer. But for a UE without identification information, such as a card-less UE (e.g., without a SIM card or eSIM card, etc.), the core network supporting behavior C (e.g., the network supports only behavior C and no other behaviors) would reject the UE's emergency registration request or request to establish an emergency bearer.

Act D, allow all UEs to establish emergency bearers.

For action D it is understood that all UEs are capable of emergency registration. For example, the core network can accept an emergency registration request or a request to establish an emergency bearer for the UE as long as the UE can provide the UE's device identification. The device identity of the UE includes, for example, an international mobile equipment identity (international mobile equipment identity, IMEI) or the like.

A core network may support one or more of the above four network behaviors, which may determine whether to accept an emergency registration request or a request to establish an emergency bearer for a UE based on the supported network behaviors and the UE's situation.

When an emergency session is established within the IMS, the IMS verifies the UE's IMS credentials. If the UE has an IMS certificate, the IMS may accept the UE's IMS registration request or request to establish an emergency session. Whereas if the UE does not have an IMS certificate, the UE may choose not to perform the IMS registration procedure, i.e. not to perform S106, but directly to perform S107. In S107, the UE sends a request for establishing an emergency session to the P-CSCF, which request may carry information of an anonymous user (anonymous user) and an emergency service indication (EMERGENCY SERVICE indication). If the P-CSCF supports anonymous users, or if the P-CSCF does not have to perform IMS registration when the P-CSCF allows an emergency call to be established, or if the P-CSCF does not require IMS registration to be performed, the P-CSCF may accept the request of the UE to establish an emergency session with the UE. And if the P-CSCF does not support anonymous users, or if the P-CSCF does not allow an emergency call to be established without having to perform IMS registration, or if the P-CSCF requires IMS registration to be performed, the P-CSCF may reject the UE's request and not establish an emergency session with the UE.

It can be seen that during the process of the UE initiating an emergency call, the emergency call may fail due to the policy of the core network and/or the IMS, which may bring about a major safety hazard.

In view of this, a technical solution of the embodiment of the present application is provided. In the embodiment of the application, the first UE can determine whether to select the relay service of the emergency service provided by the second UE and/or the first network according to the first information. For example, the first UE does not have an IMS certificate, then if the first network does not require IMS registration, the first UE may select a relay service for the second UE and/or the first network to provide emergency services, and if the first network does require IMS registration, the first UE may not select a relay service for the second UE and/or the first network to provide emergency services; for another example, if it is determined that the first network can support the first UE to establish the emergency bearer according to the network behavior information of the first network to establish the emergency bearer, the first UE may select the second UE and/or the first network to provide the relay service of the emergency service, and if it is determined that the first network does not support the first UE to establish the emergency bearer according to the network behavior information of the first network to establish the emergency bearer, the first UE may not select the second UE and/or the first network to provide the relay service of the emergency service. By the scheme of the embodiment of the application, the first UE can select the proper UE and/or network to provide the relay service of the emergency service, so that the success rate of the first UE executing the emergency service is improved, and the safety risk is reduced.

The technical solution provided in the embodiment of the present application may be applied to a fourth generation mobile communication technology (the 4th generation,4G) system, for example, a long term evolution (long term evolution, LTE) system, or may be applied to a 5G system, for example, an NR system, or may also be applied to a next generation mobile communication system or other similar communication systems, for example, a sixth generation mobile communication technology (the 6th generation,6G) system, etc., which is not specifically limited. The technical scheme provided by the embodiment of the application can also be applied to a relay scene that Yu Yuanduan (remote) UE is connected with a network through relay (relay) UE, wherein the remote UE is wearable equipment such as a smart watch, a smart bracelet or smart glasses, and the relay UE is equipment such as a smart phone or CPE.

Please refer to fig. 2, which is a schematic diagram of a 5G network architecture. The UE accesses a core network comprising user plane network elements and control plane network elements through a (radio) access network (radio access network, (R) AN). Wherein the user plane network element of the core network comprises a user plane function (user plane function, UPF); the control plane network elements of the core network include at least one of authentication server functions (authentication server function, AUSF), AMF, SMF, network slice selection functions (network slice selection function, NSSF), network opening functions (network exposure function, NEF), network function warehousing functions (NF repository function, NRF), unified data management (unified DATA MANAGEMENT, UDM), PCF, and AF.

The user plane network element (e.g., UPF) is mainly responsible for packet data packet forwarding, quality of service (quality of service, qoS) control, billing information statistics, etc. The control plane network element is mainly responsible for business process interaction, data packet forwarding strategy and QoS control strategy and the like.

The core network control plane can adopt a service architecture, namely, interaction among control plane network elements adopts a service calling mode to replace a point-to-point communication mode in the traditional architecture. In the service architecture, one control plane network element can open services to other control plane network elements for calling by the other control plane network elements; in point-to-point communication, a specific set of messages exists in a communication interface between control plane network elements, and the messages can only be used by the control plane network elements at two ends of the interface during communication.

The function of the network elements in the core network is introduced as follows:

The UPF performs user packet forwarding according to the routing rule of the SMF, such as sending uplink data to a Data Network (DN) or other UPF, and forwarding downlink data to other UPF or (R) AN.

AUSF, performing security authentication of the UE.

AMF, access management and mobility management for UEs. In charge of state maintenance of the UE, reachability management of the UE, forwarding of non-access-stratum (NAS) messages, non-mobility management (mobility management, MM), forwarding of session management (session management, SM) N2 messages.

SMF, UE session management, allocating resources for the UE session, and releasing the resources. Where the resources include session quality of service (quality of service, qoS), session paths, forwarding rules, etc.

NSSF, selecting a network slice for the UE.

The NEF opens network functions to third parties in the form of a northbound application programming interface (application programming interface, API) interface.

NRF provides storage function and selection function of network function entity information for other network elements.

UDM, user subscription context management.

PCF, user policy management, for generating, managing user, session, qoS flow handling policies.

AF, application management, functional network elements providing various business services, capable of interacting with the core network through NEF, and capable of interacting with the policy management framework for policy management.

The related interfaces between the network element functions related to the embodiment of the application comprise:

N1: an interface between the UE and a control plane of the core network.

N2: a communication interface between AN Access Network (AN) network element and a core network control plane.

And N3: and a communication interface between the access network element and the UPF is used for transmitting user data.

N4: and a communication interface between the SMF and the UPF is used for carrying out strategy configuration and the like on the UPF.

N6: communication ports between the UPF and a Data Network (DN).

Please refer to fig. 3, which is a schematic diagram of a layer 3 (L3) relay architecture. The architecture mainly involves remote UE (remote terminal device in fig. 3), relay UE (relay terminal device in fig. 3), 5G access network (next generation (NG) -RAN), 5G core network (5G core,5 gc), DN, etc. The remote UE establishes connection with the network through the relay UE, thereby acquiring the service of the network. The remote UE and the remote UE are connected, and no connection exists between the remote UE and the network.

Please refer to fig. 4, which is a schematic diagram of a layer 2 (L2) relay architecture. The architecture mainly relates to remote UE, relay UE, NG-RAN, 5GC and DN respectively connected with the remote UE and the relay UE, and the like. Unlike the L3 relay architecture, in the L2 relay architecture, there are connections between the remote UE and the NG-RAN and between the remote UE and the core network serving the remote UE, so that the remote UE can select the network by itself in the L2 relay architecture. In addition, under the L2 relay architecture, the remote UE can also select relay UE by itself. The core network element serving the remote UE includes, for example, a remote UE AMF, a remote UE SMF, a remote UE UPF, etc. in fig. 4; the core network elements serving the relay UE include, for example, relay UE AMF, relay UE SMF, relay UE UPF, and the like in fig. 4.

In addition, for both the L2 relay architecture and the L3 relay architecture, there are two alternative discovery methods, model a and model B, respectively.

Model A, for which reference is made to FIG. 5A, broadcasts a discovery claim message (announcement message) by the relay UE. In fig. 5A, UE1 broadcasts a discovery announcement message as an example, so UE1 may be referred to as an announcement (announcing) end; taking UE 2-UE 5 as an example to receive the discovery announce message, UE 2-UE 5 may be referred to as monitoring (monitoring) side. The discovery announce message includes a Relay Service Code (RSC) that may be used to indicate the relay services that the relay UE may provide. The remote UE selects a relay UE based on the discovery announce message and the demand of the remote UE. For example, if the RSC included in the discovery announce message from a certain relay UE matches the RSC required by the remote UE, the remote UE may select the relay UE, e.g., the remote UE may initiate a connection establishment procedure to the relay UE, and further perform a relay service through the relay UE.

Model B, the discovery request message (solicitation mesage) is broadcast by the remote UE first, see S51 in FIG. 5B. Fig. 5B exemplifies that UE1 broadcasts a discovery request message, and thus UE1 may be referred to as a discoverer (discoverer). The discovery request message may include an RSC indicating an identity of a relay service that the remote UE desires to be provided. In fig. 5B, since UE2 to UE5 receive the discovery request message, UE2 to UE5 may be referred to as discoveree (discoveree). The relay UE determines whether to respond to the remote UE, or, in other words, whether to be able to provide the relay service required by the remote UE, based on the discovery request message from the remote UE and the relay capability of the relay UE. For example, if the RSC requested by the remote UE matches the RSC of the relay service that the relay UE may provide, the relay UE may respond to the remote UE, e.g., the relay UE may send a discovery response message (response message) to the remote UE, see S52 in fig. 5B. The remote UE may receive discovery response messages from one or more relay UEs, for example, fig. 5B exemplifies that both UE2 and UE3 send discovery response messages to the remote UE. The remote UE selects one relay UE from the one or more relay UEs, so as to initiate a connection establishment procedure with the relay UE, thereby executing a relay service.

Referring to fig. 5C, a flowchart of a connection establishment procedure between a remote UE and a relay UE is shown. Referring to S53, the remote UE transmits a connection setup request (link establish request) message to the relay UE to request connection setup. The connection establishment request message may include an RSC for indicating an identity of a relay service for which the remote UE selects to establish a connection. Referring to S54, after receiving the connection establishment request message, if the RSC included in the connection establishment request message belongs to an RSC broadcasted by the remote UE in the discovery process, the relay UE may send a connection establishment acceptance (link establish accept) message to accept the establishment of the connection; or after receiving the connection establishment request message, the relay UE may also send a connection establishment rejection (link establish reject) message to the remote UE to reject the establishment of the connection. Among them, between the connection establishment request message and the connection establishment acceptance message/connection establishment rejection message, the remote UE and the relay UE may also interact with other messages, which is not repeated.

In order to better describe the embodiments of the present application, the method provided by the embodiments of the present application is described below with reference to the accompanying drawings. In the drawings corresponding to the embodiments of the present application, the steps indicated by the broken lines are optional steps unless specifically described below. In various embodiments of the present application, the emergency services are, for example, emergency call services, or may be other types of emergency services.

Alternatively, in various embodiments of the application, the "network" may be a PLMN.

Referring to fig. 6, a flowchart of a communication method according to an embodiment of the present application is shown. The method provided by the embodiment of the present application may be applied to the network architecture shown in fig. 3 or fig. 4, for example, the first UE involved in the method provided by the embodiment of the present application may be remote UE in fig. 3 or fig. 4; the second UE involved in the method provided by the embodiment of the present application may be a relay UE in fig. 3 or fig. 4.

S601, the second UE sends a first message. Accordingly, the first UE receives a first message from the second UE. The first message may indicate a relay service providing an emergency service. For example, the first message includes a first service code, where the first service code is a service code corresponding to the emergency service, so that the first message may indicate a relay service for providing the emergency service through the first service code. The first service code is, for example, an RSC corresponding to emergency traffic, which may be referred to as an emergency RSC (EMERGENCY RSC, EM RSC).

The first message may indicate a relay service providing an emergency service, and it may be understood that the first message may be used for the first UE to discover that the second UE is a relay device capable of providing the emergency service, or may be used for responding to a request sent by the first UE for establishing a communication connection with the second UE for transmitting data of the emergency service.

As an alternative embodiment, the first message is, for example, a discovery message. If the embodiment of the present application employs model A, the first message is, for example, a discovery announce message broadcast by the second UE.

Or if the embodiment of the application employs model B, the first message is, for example, a discovery response message sent by the second UE. Alternatively, before S601, the first UE may broadcast a second message, for example, including a second service code, which may request a relay service of the emergency service. The second service code is for example an RSC, which may also be referred to as emergency RSC, because the second service code corresponds to emergency traffic. The second message is, for example, a discovery request message. After the second UE receives the second message, if the first UE can be provided with the relay service of the emergency service, for example, the second service code is a service code authorized by the second UE as a relay, S601 may be performed.

Alternatively, embodiments of the present application may employ a combination of model A and model B, e.g., the first message is a discovery announce message sent by the second UE. Alternatively, before S601, the first UE may broadcast a second message, for example, including a second service code, which may request a relay service of the emergency service. The second service code is, for example, RSC and the second message is, for example, a discovery request message. After the second UE receives the second message, if the first UE can be provided with the relay service of the emergency service, for example, the second service code is a service code authorized by the second UE as a relay, S601 may be performed. The first message in S601 is not a discovery response message at this time, but a discovery announce message sent by the second UE, which may be sent by broadcast or unicast.

As another alternative embodiment, the first message is, for example, a response message to the connection establishment request message, which is, for example, a connection establishment acceptance message or a connection establishment rejection message. Optionally, before S601, the first UE may send a second message, for example, a connection establishment request message. The second message includes, for example, a second service code. After the second UE receives the second message, for example, the second service code is a relay service code broadcasted by the second UE in the discovery process, S601 may be executed. Wherein if the second UE is able to provide relay services of the emergency service for the first UE, the first message is, for example, a connection establishment acceptance message; or if the second UE is unable to provide relay services for the emergency service for the first UE, the first message is, for example, a connection establishment rejection message.

Alternatively, the second UE may transmit the first information upon determining that the first message indicates a relay service providing the emergency service. The second UE may not transmit the first information if the first message indicates that the provided relay service is not an emergency service. For example, the first information is transmitted when the emergency RSC is included in the first message, and the emergency RSC is not included, the first UE may not necessarily include the first information in the first message. Or alternatively, the second message sent by the first UE includes an emergency RSC, where the emergency RSC is an RSC broadcast by the second UE during the discovery process; or in yet another manner, the second message sent by the first UE includes an emergency RSC, the first message also includes an emergency RSC, and the two emergency RSCs match (e.g., are identical).

S602, the first UE determines whether to select relay service of emergency service provided by the second UE and/or the first network according to the first information. The first network is, for example, a serving network of the second UE, e.g., a serving public land mobile network (public land mobile network, PLMN) (SERVING PLMN) of the second UE, e.g., the PLMN includes the network serving the relay UE in fig. 3 or fig. 4. Or the first network may comprise, for example, a network to which the serving cell of the second UE can access, for example, the serving cell of the second UE can access one or more PLMNs, i.e., in the scenario where the operators share the radio base station, the serving cell that the base station can provide can access to multiple core networks, the first network may comprise the one or more PLMNs.

Wherein, if the number of networks included in the first network is 1, the first UE may determine whether to select a relay service for which the network provides emergency services in S602. Or if the number of networks included in the first network is greater than 1, the first UE may determine whether to select a relay service for providing emergency services to some or all of the plurality of networks in S602. For example, the first UE may determine whether relay services for the emergency services can be selected for each of the plurality of networks, respectively, or described as being able to select which network or networks of the plurality of networks provide relay services for the emergency services, respectively. The result of the first UE performing S602 may be that the first UE determines that a relay service providing emergency services can be selected for some or all of the plurality of networks or that a relay service providing emergency services cannot be selected for all of the plurality of networks.

After the first UE receives the first message, the first UE may determine the first network if the first message indicates a relay service providing the emergency service. Taking the example that the first network is the serving network of the second UE, for example, the first message comprises an NR cell global identity (NR cell global identifier, NCGI), the NCGI comprises an identity of the serving network of the second UE, the first UE can determine the serving network of the second UE according to the NCGI. Or, for example, the first network includes a network to which the serving cell of the second UE can access, the first message may include a radio resource control (radio resource control, RRC) container including identification information of one or more PLMNs to which the serving cell of the second UE can access, so that the first UE can determine the one or more PLMNs according to the first message. For ease of understanding, the embodiment of the present application will be described below with reference to the number of networks included in the first network being 1.

If the first network and the home network of the first UE are the same network, the first UE can be considered to have an effective subscription in the first network, and if the first UE is not in a limited service state, the first network does not reject the first UE in a stage of establishing an emergency bearer in the core network, and the emergency bearer can be established; in addition, since the first network is the home network of the UE, if the UE signs up for the IMS service, the first UE also has an IMS certificate of the IMS corresponding to the first network, and when an emergency session is established in the IMS, the first UE can also successfully perform IMS registration and establish the emergency session. That is, if the first network is a home network of the first UE, the first UE can perform emergency services through relay of the second UE within the first network. Thus, alternatively, if the first network includes the home network of the first UE, the first UE may select a relay service that provides emergency services for the home network, in which case the first UE may not have to perform S602, but may perform emergency services within the home network through a relay of the second UE, or the first UE may select a relay service that provides emergency services for the second UE and/or the home network, without making a decision based on the first information. Or if the first network does not include the home network of the first UE, the first UE may perform S602, or the first UE may determine whether to select a relay service for the second UE and/or the first network to provide the emergency service according to the first information. Or even if the first network includes the home network of the first UE, the first UE may perform S602, for example, the first UE may determine whether to select the second UE and/or the relay service of the home network providing the emergency service according to the first information. The home network of the first UE is, for example, a Home PLMN (HPLMN) of the first UE. The number of networks comprised by the home network of the first UE may be one or more, and in addition, as known from the foregoing, the number of networks comprised by the first network may be one or more. Alternatively, in various embodiments of the present application, if there is an intersection between the home network of the first UE and the first network (e.g., the number of intersection networks is one or more), the intersection network may be considered to be the home network of the first UE, where the first network includes the home network of the first UE; and if there is no intersection between the home network of the first UE and the first network, the first network may be considered to not include the home network of the first UE.

The first information may comprise information whether the first network requires IMS registration to be performed and/or network behavior information comprising the first network establishing an emergency bearer. Alternatively, the first information may be considered to comprise second information and/or third information, wherein the second information comprises information whether the first network requires IMS registration to be performed or not, and the third information comprises network behavior information for the first network to establish an emergency bearer. Alternatively, if the first UE is a remote UE of the L3 type and/or the second UE is a relay UE of the L3 type, in S602, the first UE may determine whether to select the relay service of the second UE for providing the emergency service according to the first information, instead of determining whether to select the relay service of the first network for providing the emergency service according to the first information. Because the first UE is not connected to the first network under the L3 relay architecture, the first UE does not have to perform an operation of selecting a network. Or even if the first UE is a remote UE of the L3 type and/or the second UE is a relay UE of the L3 type, in S602, the first UE may determine whether to select the relay service of the emergency service provided by the second UE according to the first information, or whether to select the relay service of the emergency service provided by the first network according to the first information.

Or if the first UE is a remote UE of the L2 type and/or the second UE is a relay UE of the L2 type, the first UE may determine whether to select a relay service of the first network providing the emergency service according to the first information (e.g., the first network includes a set of candidate networks considered as the first UE, the first UE may select a network from the set of candidate networks according to the first information to provide the emergency service). Because the first UE has a connection with the first network under the L2 relay architecture, the first UE may perform an operation of selecting a network. Alternatively, after selecting the network according to the first information, the first UE may continue to select a relay UE capable of providing the relay service of the emergency service under the network, where the first UE may not need to refer to the first information when selecting the relay UE under the network. For example, the first UE may select a UE capable of providing a relay service for emergency services through a discovery procedure, or select a UE capable of providing a relay service for emergency services and having a better signal quality. For example, the first UE determines, according to the first information, that the relay service capable of providing the emergency service by the first network can be selected, and then the first UE may select a relay UE that uses the relay service capable of providing the emergency service as a service network in the first network, and the first UE may eventually select the second UE, or may select other UEs. Wherein the first UE may not need to refer to the first information when selecting the relay UE. That is, in this manner, the first information may be used to select a network, but may not be used to select a relay UE.

Or if the first UE is a remote UE of the L2 type and/or the second UE is a relay UE of the L2 type, the first UE may determine whether to select a relay service for the first network and the second UE to provide emergency services according to the first information (e.g., the first network includes a set of candidate networks that are considered as the first UE, the first UE may select a network from the set of candidate networks according to the first information to provide the emergency services, if the first UE selects one or more networks from the set of candidate to provide the emergency services, the first UE needs to connect with the one or more networks by means of the second UE to perform the emergency services, or the first UE needs to acquire the emergency services provided by the one or more networks by means of the relay service provided by the second UE). Because the first UE has a connection with the first network under the L2 relay architecture, the first UE may perform an operation of selecting a network; in addition, the first UE is connected to the first network through the relay UE, so the first UE may perform an operation of selecting the relay UE. In this way, the first information is used for both selecting the network and selecting the relay UE.

The first UE may determine whether to select the relay service of the emergency service provided by the second UE and/or the first network according to the first information, and may obtain the first information first in various manners, for example, as described below.

As an alternative embodiment for the first UE to acquire the first information, the first network device sends the first configuration information to the first UE, and the first UE may acquire the first information according to the first configuration information, for which reference may be made to S603 in fig. 6. The first configuration information may include information whether the second network requires IMS registration to be performed and/or network behavior information including the second network establishing an emergency bearer. Wherein the second network may comprise a network to which the first UE is authorized to access, e.g. comprising a PLMN to which the first UE is authorized to access. The second network may comprise one or more PLMNs and the first network may belong to the second network, e.g. the first network is a PLMN comprised by the second network. The first network device may be a device within the HPLMN of the first UE, for example the first network device is a UDM, or may be another core network device, and the UDM may send the first configuration information directly to the first UE without being relayed through another device. For example, the first UE may send the first configuration information to the first UE during registration with the HPLMN of the first UE, or after the first UE completes registration within the HPLMN. Alternatively, the first configuration information may be included in the roaming guide (steering of roaming) information, or may be transmitted through other information. The first network device may be another device in the HPLMN of the first UE, or a device in another PLMN other than the HPLMN, for example, a third party server, etc., and the first network device may directly send the first configuration information to the UE, or the first network device may be a relay device of the first configuration information. Wherein the HPLMN of the first UE may have a roaming agreement with at least one other PLMN, wherein the UEs within the PLMNs may roam with each other. For a UE (e.g., a first UE) within the HPLMN, may be authorized to access all or part of the PLMNs in the at least one PLMN, that is, the first UE may be able to roam in the all or part of the PLMNs, then the second network may include the all or part of the PLMNs.

As another alternative embodiment of the first UE obtaining the first information, the second network device sends the second configuration information to the first UE, and the first UE may obtain the first information according to the second configuration information, for which reference may be made to S604 in fig. 6. The first UE may perform S603 or S604, that is, perform one of the steps. It will be appreciated that S603 and S604 represent two parallel solutions, and thus one of the steps may be performed. Or the first UE may not perform S603 and S604, for example, the first UE acquires the first information through other means described later (for example, the first message includes the first information, which will be described later), the first UE may not perform S603 and S604. The second configuration information is, for example, proximity-based services (ProSe) configuration. Alternatively, if the first UE is a remote UE of the L2 type, or the first UE supports the L2 relay architecture, the first UE may obtain the first information in this way. Or even if the first UE is a remote UE of the L3 type, or the first UE supports the L3 relay architecture, the first UE may obtain the first information in this way. The second configuration information may include information whether the third network requires IMS registration to be performed and/or network behavior information including the third network establishing an emergency bearer. Wherein the third network may comprise a network in which the first UE is authorized as a remote UE, or a network in which the first UE is authorized to use relay services. For example, the third network may include a PLMN in which the first UE is authorized as a remote UE, or a PLMN in which the first UE is authorized to use relay services. The third network may comprise one or more PLMNs and the first network may belong to the third network, e.g. the first network is one of the PLMNs comprised by the third network. The second network device may be a device within the HPLMN of the first UE, e.g. the second network device is a PCF, or may be another core network device. Or the second network device may be another device within the HPLMN of the first UE or a device within a PLMN other than the HPLMN, such as a third party server or the like. The second network device may directly send the second configuration information to the first UE, or the second network device may also be a relay device of the second configuration information.

As yet another alternative embodiment of the first UE obtaining the first information, the first message includes the first information, and the first UE may obtain the first information included in the first message. In this manner, the first information may be transmitted by the second UE to the first UE. For example, the second UE may acquire the first information and transmit the first information to the first UE through the first message. The second UE may acquire the first information in different manners, which will be described below.

As an alternative implementation manner for the second UE to acquire the first information, the fourth network device sends third configuration information to the second UE, and the second UE may acquire the first information according to the third configuration information. This step is also referred to in the embodiment shown in fig. 7 to be described later, and is S703 in fig. 7. The third configuration information may include information whether the fourth network requires IMS registration to be performed and/or network behavior information including the fourth network establishing an emergency bearer. Wherein the fourth network may comprise a network to which the second UE is authorized to access, e.g. comprising a PLMN to which the second UE is authorized to access. The fourth network may comprise one or more PLMNs and the first network may belong to the fourth network, e.g. the first network is a PLMN comprised by the fourth network. The fourth network device is a device within the HPLMN of the second UE, for example, the fourth network device is a UDM, or may be another core network device, and the UDM may directly send the third configuration information to the second UE, without being transferred through another device. For example, the UDM in the HPLMN may send the third configuration information to the second UE during registration with the HPLMN of the second UE or after the second UE completes registration in the HPLMN. Alternatively, the third configuration information may be included in the roaming guide information, or may be transmitted through other information. The fourth network device may be another device in the HPLMN of the first UE, or a device in another PLMN other than the HPLMN, for example, a third party server, etc., and may directly send the third configuration information to the UE, or the fourth network device may be a relay device of the third configuration information. Wherein the HPLMN may have a roaming agreement with at least one other PLMN, wherein UEs within the PLMNs may roam with each other. For a UE (e.g., a second UE) within the HPLMN that may be authorized to access all or part of the PLMNs in the at least one PLMN, that is, the second UE may be able to roam in the all or part of the PLMNs, the fourth network may include the all or part of the PLMNs.

As another alternative implementation manner of the second UE obtaining the first information, the fifth network device sends fourth configuration information to the second UE, and the second UE may obtain the first information according to the fourth configuration information. This step is also referred to in the embodiment shown in fig. 7, which will be described later, and is S704 in fig. 7. The fourth configuration information is, for example, proSe configuration. The fourth configuration information may include information whether the fifth network requires IMS registration to be performed and/or network behavior information including the fifth network establishing an emergency bearer. Wherein the fifth network may include a network in which the second UE is authorized as a relay UE, or a network in which the first UE is authorized to provide relay services. For example, the fifth network includes a PLMN in which the second UE is authorized as a relay UE, or includes a PLMN in which the second UE is authorized to provide relay services. The fifth network may comprise one or more PLMNs and the first network may belong to the fifth network, e.g. the first network is one of the PLMNs comprised by the fifth network. The fifth network device may be a device within the HPLMN of the second UE, e.g. the fifth network device is a PCF, or may be another core network device. Or the fifth network device may be another device within the HPLMN of the second UE or a device within a PLMN other than the HPLMN, such as a third party server or the like. The fifth network device may directly send the fourth configuration information to the second UE, or the fifth network device may also be a relay device of the fourth configuration information.

Wherein the network in which the second UE is authorized as a relay UE, or the network in which the second UE is authorized to provide relay services, may include a network in which the second UE is authorized to perform L2 relay and/or a network in which the second UE is authorized to perform L3 relay. For example, the fifth network device may determine in which PLMNs the second UE is authorized to perform L2 relay and/or in which PLMNs the second UE is authorized to perform L3 relay, such that the fifth network may be determined. Wherein if the second UE is capable of executing the L2 relay, indicating that the second UE is a relay UE of the L2 type; if the second UE is capable of executing the L3 relay, it is indicated that the second UE is an L3 type relay UE. Within one PLMN, the second UE may be able to function as only an L2 type relay UE or as only an L3 type relay UE, or the second UE may also function as both an L2 type relay UE and an L3 type relay UE.

As yet another alternative embodiment where the second UE obtains the first information, the third network device sends the first information to the second UE, which may receive the first information from the third network device. This step is also referred to in the embodiment shown in fig. 7 to be described later, and is S705 in fig. 7. Alternatively, in the embodiment of the present application and the embodiment shown in fig. 7, the three steps (e.g., S703 to S705) of the second UE obtaining the first information may be performed alternatively. It will be appreciated that these three steps represent three parallel solutions, so that one of these three steps may be performed. The third network device may be a device within the HPLMN of the second UE, for example the third network device is an AMF, or may be another core network device. For example, the second UE may send the first information to the second UE during registration with the HPLMN of the second UE, or after registration within the HPLMN is completed, by an AMF within the HPLMN. Or the third network device may be another device within the HPLMN of the second UE or a device within a PLMN other than the HPLMN, such as a third party server or the like. The third network device may send the first information directly to the second UE, or the third network device may also be a relay device of the first information.

If the first UE obtains the first information through the first message, if the second UE can only act as an L3 type relay UE and cannot act as an L2 type relay UE in the first network, the first information may include information whether the first network requires IMS registration to be performed and does not include network behavior information for the first network to establish an emergency bearer, or alternatively, the first information may include the second information and does not include the third information. If the second UE can only be used as the L3 type relay UE in the first network, the first UE is indicated to be connected with the second UE and the first network through the L3 relay architecture in the first network. Under this architecture, there is no connection between the first UE and the first network, the first UE does not establish an emergency bearer within the first network, and therefore the first UE may not have to determine the network behavior of the first network to establish an emergency bearer. Or even if the second UE can only act as an L3 type relay UE and cannot act as an L2 type relay UE within the first network, the first information may include the second information and the third information because, although there is no connection between the first UE and the first network, it may be determined whether the network behavior of the first network supports the first UE first if the connection between the second UE and the first network is to be used. Or if the second UE can only function as an L2 type relay UE and cannot function as an L3 type relay UE in the first network, or the second UE can function as both an L2 type relay UE and an L3 type relay UE in the first network, the first information may include the second information and the third information. If the second UE can be used as the relay UE of the L2 type in the first network, the first UE can be connected with the second UE and the first network through the L2 relay architecture in the first network. Under this architecture, there is a connection between the first UE and the first network, where the first UE is to establish an emergency bearer within the first network, so the first UE may determine a network behavior of the first network to establish the emergency bearer.

If the first UE obtains the first information through the first message, the first information may be optionally included in an RSC corresponding to the emergency service, and thus may be referred to as an emergency RSC. For example, the emergency RSC may include a service code and first information. In this case, the emergency RSC may be included as the first message, or the emergency RSC may be included in the first message. When the emergency RSC includes a service code and first information, the RSC may define certain bits (e.g., N bits) therein to indicate that the RSC is the emergency RSC, and in addition, certain bits (e.g., 1 bit) therein to indicate whether the first network requires IMS registration (e.g., 0) may indicate that the first network does not require IMS registration, and in addition, two bits (e.g., 2 bits) therein to indicate network behavior information (e.g., 00) for the first network to establish an emergency bearer, to indicate network behavior a, to indicate network behavior B, to indicate network behavior C, to indicate network behavior D, to indicate network behavior C, to indicate network behavior 0), or in addition, to indicate network behavior (e.g., 1 bit) to indicate that the first network establishes an emergency bearer, to indicate that the network behavior does not accept all UEs, i.e., to establish an emergency bearer, to indicate any one of network behaviors a to D, to accept any of network behaviors D, to 1).

Or the first information may be separate parameters that are interacted with during a discovery procedure or a connection establishment procedure between the first UE and the second UE, e.g. the first information and the emergency RSC may be included in the same message (e.g. the first message), or the first information and the emergency RSC may be included in different messages. When the first information is an independent parameter, the information for indicating whether the first network requires IMS registration and the network behavior information for the first network to establish an emergency bearer may be expressed using one independent parameter (e.g., using 3 bits, the first 1 bit indicating whether the first network requires IMS registration, the second 2 bits indicating the network behavior information for the first network to establish an emergency bearer, or using 2 bits, the first 1 bit indicating whether the first network requires IMS registration, the second 1 bit indicating the network behavior information for the first network to establish an emergency bearer); two parameters may also be used to represent information indicating whether the first network requires IMS registration to be performed and network behavior information for the first network to establish an emergency bearer, respectively (i.e. using 1 bit for each). For a specific coding manner example, refer to a case that the emergency RSC includes the service code and the first information, which will not be described herein.

In addition to the above description of several ways in which the first UE obtains the first information and the second UE obtains the first information, the embodiments of the present application do not limit that the first UE and/or the second UE may also obtain the first information in other ways.

The foregoing describes that the first information includes the second information and/or the third information, and the manner in which the first UE performs S602 may also be different when the information included in the first information is different, which is described by way of example below.

1. The first information includes second information. The first UE may determine whether to select a relay service for the second UE and/or the first network to provide the emergency service according to the second information in S602.

For example, if the second information indicates that the first network does not require IMS registration (in various embodiments of the present application, one network does not require IMS registration, or it may be described that the network does not require IMS registration to be performed before or during establishment of an emergency session, or it may not require IMS registration to be performed during or during establishment of an emergency session, or it may be described that the network requires IMS registration to be performed during establishment of an emergency session, or it may be described that the network does not require IMS registration to be performed during establishment of an emergency session, or it may not require anonymous user to establish an emergency session, as described later herein), the first UE may allow the first UE to establish an emergency session without IMS registration, even without IMS credentials of the IMS to which the first network corresponds, and therefore the first UE may choose the second UE and/or the first network to provide relay services for services of the service.

Or if the second information indicates that the first network requires IMS registration to be performed and the first UE has an IMS certificate of the first network (or, the first UE has an IMS certificate of an IMS corresponding to the first network), the first UE may select the second UE and/or the first network to provide a relay service for the emergency service. The first UE has an IMS certificate of an IMS corresponding to the first network, and can perform IMS registration in the IMS through the IMS certificate, so that the first UE can select the second UE and/or the first network to provide a relay service of the emergency service.

Or if the second information indicates that the first network requires IMS registration to be performed and the first UE does not have an IMS certificate of the first network, the first UE may not select the relay service for the second UE and/or the first network to provide the emergency service. The first UE does not have an IMS certificate of the first network, and the first UE cannot perform IMS registration within the IMS. However, the IMS does not allow the IMS registration to be performed when the emergency session is established, i.e. the first UE needs to perform IMS registration when the emergency session is to be established in the IMS, so that the first UE does not meet the condition for establishing the emergency session in the IMS, and may not select the second UE and/or the relay service of the first network to provide the emergency service. In various embodiments of the present application, if the first UE does not select a UE and/or the first network provides a relay service of an emergency service, it may also be understood that the first UE does not select a relay UE in the network, or that the first UE does not select a UE serving the network as the relay UE. Optionally, if the first UE does not select a UE and/or the first network provides the relay service of the emergency service, the first UE may reselect the relay UE and/or the network to provide the relay service of the emergency service, so as to improve the success rate of executing the emergency service.

Wherein the first UE has an IMS certificate of the first network, which may be understood as the first UE having a valid IMS certificate of the first network; the first UE does not have an IMS certificate of the first network, which may be understood as the first UE does not have a valid IMS certificate of the first network. The first UE is able to register with an IMS corresponding to a certain network if it has a valid IMS certificate within the IMS, and is unable to register with the IMS if it does not. For example, the first UE signs up for IMS services at the HPLMN, then typically will have IMS credentials for the HPLMN. The IMS certificate can be verified by the HPLMN without the first UE roaming, the IMS certificate being considered to be a valid IMS certificate for the HPLMN that the first UE has; or the first UE has a communication interface between the roaming network and the IMS of the HPLMN although roaming, the IMS certificate can also be verified by the roaming network (the roaming network can verify through the HPLMN and obtain a verification result), and the IMS certificate is also considered to be a valid IMS certificate of the roaming network or a valid IMS certificate on the roaming network that the first UE has.

Alternatively, if the first network is the HPLMN of the first UE, the first UE may have a valid IMS certificate of the first network. Or, although the first network is not the HPLMN of the first UE, the first network is a network that the first UE can roam (or is a network that the first UE is authorized to access), or the first network is a network that the first UE is authorized to use relay services, i.e. the first UE can connect to the first network through a relay UE within the first network, the first network can interact with the HPLMN of the first UE to obtain the IMS certificate, although the IMS certificate possessed by the first UE may not be the IMS certificate of the first network (e.g. is the IMS certificate of the HPLMN of the first UE), so the first UE can also be considered to have a valid IMS certificate of the first network. Or, although the first network is not the HPLMN of the first UE, the first network is able to verify the IMS certificate of the first UE, in which case the first UE is also considered to have a valid IMS certificate of the first network. For example, although the first network is not the HPLMN of the first UE, the IMS of the first network and the IMS of the HPLMN of the first UE have an interworking capability, which is understood to be that there is a communication interface between the IMS of the first network and the IMS of the HPLMN of the first UE, and subscription information such as an IMS certificate can be transferred, so that the first network can verify the IMS certificate of the first UE through such interworking capability with the IMS of the HPLMN of the first UE.

And if the first network is not the HPLMN of the first UE, and the first network is not the network to which the first UE is authorized to access, nor is the first network authorized to use the relay service, and the first network is also unable to verify the IMS credentials of the first UE (e.g., there is no interworking capability between the IMS of the first network and the IMS corresponding to the HPLMN of the first UE), then the first UE is deemed to have no valid IMS credentials for the first network.

2. The first information includes third information. The first UE may determine whether to select a relay service for the second UE and/or the first network to provide the emergency service according to the third information in S602.

The first UE may select the relay service for providing the emergency service by the second UE and/or the first network if the first UE determines that the emergency bearer can be established in the first network according to the third information. Or if the first UE determines that the emergency bearer cannot be established in the first network according to the third information, the first UE may not select the second UE and/or the first network to provide the relay service of the emergency service. The third information includes network behavior information of the first network to establish the emergency bearer, where the network behavior of the first network to establish the bearer may be any one or more of the behaviors a to D described above, which may be understood that the third information includes information indicating the network behavior, and the first UE may determine whether to establish the emergency bearer in the first network according to the network behavior information.

For example, the third information indicates that the network behavior of the first network includes allowing all UEs to establish an emergency bearer (i.e., indicates that the network behavior of the first network includes behavior D), the first UE can establish an emergency bearer in the first network whenever the first UE has a device identity (e.g., IMEI, etc.) regardless of whether the first UE has a valid subscription in the first network or whether the first UE is successfully registered in the first network. In this case, the first UE determines that an emergency bearer can be established at the first network.

Or the third information indicates that the network behavior of the first network includes allowing only UEs having the identification information to establish emergency bearers (i.e., indicates that the network behavior of the first network includes behavior C). Then, if the first UE has the identification information, the first UE may determine that an emergency bearer can be established at the first network; and if the first UE does not have the identification information, the first UE may determine that an emergency bearer cannot be established at the first network. The identification information includes, for example, one or more of an IMSI, SUPI, globally unique temporary UE identity (globally unique temporary UE identity, GUTI), or 5G-GUTI. Or the first UE is considered to have identification information as long as the UE has a communication module such as a SIM, a universal subscriber identity module (universal subscriber identity module, USIM), or eSIM.

Or the third information indicates that the network behaviour of the first network comprises allowing only UEs with a valid subscription to establish emergency bearers (i.e. indicates that the network behaviour of the first network comprises behaviour B). Then, if the first UE has a valid subscription on the first network, the first UE may determine that an emergency bearer can be established on the first network regardless of whether the first UE is in a limited service state; and if the first UE does not have a valid subscription in the first network, the first UE determines that an emergency bearer cannot be established in the first network.

Either the third information indicates that the network behavior of the first network includes allowing only UEs having a valid subscription and successfully registering with the network to establish emergency bearers, or the third information indicates that the network behavior of the first network includes allowing only UEs having a valid subscription and not in a limited service state to establish emergency bearers (i.e., the network behavior of the first network includes behavior a). Then, if the first UE has a valid subscription with the first network and the first UE is not in a limited service state, the first UE may determine that an emergency bearer can be established with the first network; or if the first UE does not have a valid subscription in the first network and/or the first UE is in a limited service state, the first UE determines that an emergency bearer cannot be established in the first network.

Alternatively, if the first network is the HPLMN of the first UE, the first UE may have a valid subscription for the first network. Or the first network is a network to which the first UE is authorized to access, although the first network is not the HPLMN of the first UE, or the first network is a network to which the first UE is authorized to use the relay service, the first network can interact with the HPLMN of the first UE to obtain subscription information, although the subscription information possessed by the first UE may not be subscription information within the first network (e.g., subscription information within the HPLMN of the first UE), and thus the first UE may also be considered to have a valid subscription for the first network. Or if the first network is not the HPLMN of the first UE and the first network is not the network to which the first UE is authorized to access and is also not the network to which the first UE is authorized to use the relay service, the first UE is considered to not have a valid subscription for the first network even though the first UE has subscription information within the HPLMN of the first UE (i.e., the first UE has a subscription, or has subscription information).

The first information may include the second information or the third information, or may include the second information and the third information. For example, if the first UE is a remote UE of the L3 type and/or the second UE is a relay UE of the L3 type, the first information may include the third information without the second information, or the first information may also include the second information and the third information. Or if the first UE is a remote UE of the L2 type and/or the second UE is a relay UE of the L2 type, the first information may include the second information and the third information. The case where the first information includes the second information and the third information is described below.

3. The first information includes second information and third information. The first UE may determine whether to select a relay service for the second UE and/or the first network to provide the emergency service according to the second information and the third information in S602. In this case, the first UE may determine to select a relay service for the second UE and/or the first network to provide the emergency service when the second information and the third information are simultaneously satisfied; and if the second information is not satisfied and/or the third information is not satisfied, the first UE may determine not to select the relay service for providing the emergency service by the second UE and/or the first network.

For example, the second information indicates that the first network does not require IMS registration to be performed, and the first UE determines that an emergency bearer can be established in the first network according to the third information, the first UE may select the second UE and/or the first network to provide a relay service for the emergency service.

Or the second information indicates that the first network does not require IMS registration, and the first UE determines, according to the third information, that the emergency bearer cannot be established in the first network, the first UE may not select the second UE and/or the first network to provide the relay service of the emergency service.

Or the second information indicates that the first network requires to perform IMS registration, and the first UE has an IMS certificate of the first network, and determines that the first UE can establish an emergency bearer in the first network according to the third information, the first UE may select the second UE and/or the first network to provide a relay service of the emergency service.

Or the second information indicates that the first network requires to perform IMS registration, the first UE has an IMS certificate of the first network, and the first UE determines that the emergency bearer cannot be established in the first network according to the third information, so that the first UE may not select the second UE and/or the first network to provide the relay service of the emergency service.

Or the second information indicates that the first network requires to perform IMS registration, and the first UE does not have an IMS certificate of the first network, and the first UE determines, according to the third information, that an emergency bearer can be established in the first network, the first UE may not select the second UE and/or the first network to provide a relay service of the emergency service.

Or the second information indicates that the first network requires to perform IMS registration, the first UE does not have an IMS certificate of the first network, and the first UE determines that the emergency bearer cannot be established in the first network according to the third information, so that the first UE may not select the second UE and/or the first network to provide a relay service of the emergency service.

For some details, reference may be made to clause 1 and/or clause 2 above, which are not repeated.

As to the result of the first UE determining whether to select the relay service for the emergency service provided by the second UE and/or the first network according to the first information, one or more items in table 1 may also be referred to.

TABLE 1

The "network subscription" in table 1 merely indicates that the UE has a network subscription, but the network subscription may or may not be valid. Similarly, "IMS certificate present" in table 1 merely indicates that the UE has an IMS certificate, but the IMS certificate may or may not be valid.

In table 1, "-v" indicates that the first UE selects a relay service for providing emergency services by the second UE and/or the first network; "x" indicates that the first UE does not select the relay service for the second UE and/or the first network to provide emergency services; "-" indicates a misconfiguration, i.e., this generally does not occur.

For example, if the first network is the HPLMN of the first UE, the case of the first UE may be case 1 in table 1 (at this point, the first UE has a valid subscription for the first network, and has a valid IMS certificate for the first network). Or if the first network is not the HPLMN of the first UE but is a roaming PLMN of the first UE, there is a roaming agreement between the first network and the HPLMN of the first UE, but no interworking is possible between the IMS of the first network and the IMS of the HPLMN of the first UE, the IMS certificate is an invalid IMS certificate even if the first UE has the IMS certificate of the HPLMN, at which point the first UE is considered to have no valid IMS certificate within the first network, which may be case 2 in table 1. Or if the first network is not the HPLMN of the first UE but a roaming PLMN of the first UE, there is also no roaming agreement between the first network and the HPLMN of the first UE, the case of the first UE may be case 3 in table 1.

For example, the first UE has subscription information for the first network and also has IMS credentials for the first network. If the network behavior of the first network is behavior a and the first network requires IMS registration, if the subscription information of the first network possessed by the first UE is valid subscription and the first UE is not in a limited service state and the IMS certificate is a valid IMS certificate, the first UE may select a relay service for providing emergency services by the second UE and/or the first network, and case 1 of table 1 is taken as an example; or if one or more of the following are satisfied: the subscription information of the first network that the first UE has is not a valid subscription (or an invalid subscription), the first UE is in a limited service state, or the IMS certificate is not a valid IMS certificate (or an invalid IMS certificate), and the first UE may not select the second UE and/or the first network to provide the relay service of the emergency service.

For another example, the first UE has subscription information for the first network and does not have IMS credentials for the first network. If the network behavior of the first network is behavior B and the first network does not require to perform IMS registration, if the subscription information of the first network possessed by the first UE is a valid subscription, the first UE may select the second UE and/or the first network to provide a relay service of the emergency service, which is exemplified in case 1 of table 1; or if the subscription information of the first network that the first UE has is not a valid subscription, the first UE may not select the relay service that the second UE and/or the first network provide the emergency service, which is exemplified by case 2 of table 1.

For another example, the first UE has subscription information for the first network and does not have IMS credentials for the first network. If the network behavior of the first network is behavior B and the first network requires IMS registration to be performed, the first UE may not select the relay service for the second UE and/or the first network to provide emergency services.

As another example, the first network allows all UEs to establish emergency bearers but requires IMS registration to be performed, which is an unreasonable behaviour, so the configuration is considered an unreasonable configuration, denoted by "-" in table 1. The cases included in table 1 are not exemplified.

If the first UE is a remote UE of the L2 type and/or the second UE is a relay UE of the L2 type, it may be determined whether to select the relay service of the second UE and/or the first network to provide the emergency service in the manner as described in table 1 above. Or if the first UE is a remote UE of the L3 type, the first UE may consider the second information without considering the third information in determining whether to select the second UE and/or the relay service of the first network providing the emergency service, e.g., the selection manner of the first UE may refer to table 2.

TABLE 2

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For example, the first UE has an IMS certificate of the first network. If the first network requires IMS registration to be performed, then if the IMS certificate is a valid IMS certificate, the first UE determines a relay service capable of selecting the second UE and/or the first network to provide emergency services, as exemplified in table 1; or if the IMS certificate is an invalid IMS certificate, the first UE determines that the second UE and/or the relay service of the first network providing the emergency service cannot be selected.

For another example, the first UE does not have an IMS certificate of the first network. Then, if the first network requires to perform IMS registration, the first UE determines that the second UE and/or the first network cannot be selected to provide a relay service for emergency services; or if the first network does not require IMS registration, the first UE determines a relay service capable of selecting the second UE and/or the first network to provide emergency services.

Alternatively, the first UE may perform S602 in case it is determined that the emergency RSC exists, and if the emergency RSC does not exist, the first UE may not need to determine whether to select a relay service for the second UE and/or the first network to provide the emergency service according to the first information. For example, one way in which an emergency RSC exists is that the first message includes an emergency RSC; or another manner in which the emergency RSC exists, the second message sent by the first UE includes the emergency RSC; or in a further manner that there is an emergency RSC, the second message sent by the first UE includes an emergency RSC, the first message also includes an emergency RSC, and the two emergency RSCs match (e.g., are identical).

In the embodiment of the application, the first UE can select the proper UE and/or network to provide the relay service of the emergency service by judging according to the first information, so that the success rate of the first UE for executing the emergency service is improved, and the safety risk is reduced.

In the embodiment shown in fig. 6, the first UE may select the UE and/or the network by itself to provide the relay service for the emergency service. Next, a second communication method provided by the embodiment of the present application is described, in which a second UE may determine whether to provide a relay service of an emergency service for a first UE. Please refer to fig. 7, which is a flowchart of the method. The method provided by the embodiment of the present application may be applied to the network architecture shown in fig. 3 or fig. 4, for example, the first UE involved in the method provided by the embodiment of the present application may be remote UE in fig. 3 or fig. 4; the second UE involved in the method provided by the embodiment of the present application may be a relay UE in fig. 3 or fig. 4.

S701, the first UE sends a first message to the second UE. Accordingly, the second UE receives the first message from the first UE. The first message may be used to request a relay providing emergency services.

Alternatively, the first message may include information of the home network of the first UE (e.g., the HPLMN of the first UE), e.g., including identification information of the HPLMN. The number of networks comprised by the home network of the first UE may be one or more.

Alternatively, the first message may include identification information of the first UE. The identification information of the first UE includes, for example, one or more of the following: IMSI, SUPI, GUTI,5G-GUTI, or, IMEI.

Wherein the first message may be used for requesting a relay providing an emergency service, it is understood that the first message may be used for discovering a relay device capable of providing an emergency service, or for requesting a communication connection to be established between the discovered relay devices capable of providing an emergency service, the communication connection being used for transmitting data related to the emergency service between the first UE and the second UE. The first message may be a broadcast message or a unicast message.

S702, the second UE determines whether to provide the relay service of the emergency service for the first UE according to the first information.

For example, the second UE may acquire the first information before S702, so that it may be determined whether to accept the request of the first UE according to the first information in S702, or it may be determined whether to provide the relay service of the emergency service for the first UE according to the first information in S702. For the first information and the manner in which the second UE acquires the first information, reference may be made to the embodiment shown in fig. 6. For example, the method further includes optional steps S703 to S705, where S703 is a process that the fourth network device sends the third configuration information to the second UE, S704 is a process that the fifth network device sends the fourth configuration information to the second UE, and S705 is a process that the third network device sends the first information to the second UE, and for more description of these steps, reference may be made to the embodiment shown in fig. 6.

The first information may include second information and/or third information, where the content included in the first information is different, and the manner in which the second UE performs S702 may also be different, which is described by way of example below.

1. The first information includes second information, and the second UE may determine whether to provide the relay service of the emergency service for the first UE according to the second information in S702. For example, if the first UE is a remote UE of the L3 type and/or the second UE is a relay UE of the L3 type, the second UE may determine according to the second information, without considering the third information.

For example, if the second information indicates that the first network does not require IMS registration to be performed, the second UE may provide relay services for emergency services for the first UE. For an introduction of the first network reference is made to the embodiment shown in fig. 6.

Or if the second information indicates that the first network requires IMS registration to be performed, the second UE may provide relay services for emergency services for the first UE or not provide relay services for emergency services for the first UE. The second information indicates that the first network requires IMS registration to be performed, and the second UE does not know whether the first UE has a valid IMS certificate of the first network, and may or may not provide relay services of emergency services for the first UE.

Wherein the first UE has an IMS certificate of the first network, which may be understood as the first UE having a valid IMS certificate of the first network; the first UE does not have an IMS certificate of the first network, which may be understood as the first UE does not have a valid IMS certificate of the first network. For this, reference is made to the embodiment shown in fig. 6.

2. The first information includes third information, and the second UE may determine whether to provide the relay service of the emergency service for the first UE according to the third information in S702.

For example, the third information indicates that the network behavior of the first network includes allowing all UEs to establish an emergency bearer (i.e., indicates that the network behavior of the first network includes behavior D), then the second UE may provide relay services of emergency services for the first UE if the first message includes identification information of the first UE or the second UE has obtained the identification information of the first UE. At this time, the identification information of the first UE may include one or more of the following: IMSI, SUPI, GUTI, IMEI, or, 5G-GUTI.

Or the third information indicates that the network behavior of the first network includes allowing only the UE having the identification information to establish an emergency bearer (i.e., indicates that the network behavior of the first network includes behavior C), and the first message includes the identification information of the first UE, or the second UE has obtained the identification information of the first UE, the second UE may provide the relay service of the emergency service for the first UE. At this time, the identification information of the first UE may include one or more of the following: IMSI, SUPI, GUTI, or, 5G-GUTI.

Or if the third information indicates that the network behavior of the first network includes allowing only UEs having a valid subscription to establish an emergency bearer (i.e., the network behavior of the first network includes behavior B), or includes allowing only UEs having a valid subscription and successfully registering with the network to establish an emergency bearer (i.e., the network behavior of the first network includes behavior a), the second UE may not provide a relay service of the emergency service for the first UE regardless of whether the first message includes identification information of the first UE or whether the second UE has obtained the identification information of the first UE.

Or if the first message does not include any identification information of the first UE and the second UE does not obtain any identification information of the first UE, the second UE may not provide relay services of emergency services for the first UE, regardless of what the third information indicates network behavior of the first network.

Or if the first message includes the device identity (e.g., IMEI) of the first UE without including other identities of the first UE, and/or the second UE has obtained the device identity of the first UE without obtaining other identities of the first UE, and the third information indicates that the network behavior of the first network includes one or more of behavior a, behavior B, or behavior C (or the third information indicates that the network behavior of the first network is not behavior B), the second UE may not provide relay services for emergency services for the first UE.

3. The first information includes second information and third information, and the second UE may determine whether to provide the relay service of the emergency service for the first UE according to the second information and the third information in S702. For example, if the first UE is a remote UE of the L2 type and/or the second UE is a relay UE of the L2 type, the second UE may be determined according to the second information and the third information. Or even if the first UE is a remote UE of the L3 type and/or the second UE is a relay UE of the L3 type, the second UE may also be determined according to the second information and the third information.

For example, the second information indicates that the first network does not require IMS registration to be performed, and the third information indicates that the network behaviour of the first network includes allowing all UEs to establish emergency bearers (i.e. the network behaviour of the first network includes behaviour D), then if the first message includes identification information of the first UE, or the second UE has obtained the identification information of the first UE, the second UE may provide relay services of emergency services for the first UE. At this time, the identification information of the first UE may include one or more of the following: IMSI, SUPI, GUTI, IMEI, or, 5G-GUTI.

Or the second information indicates that the first network requires IMS registration to be performed, and the third information indicates that the network behaviour of the first network includes allowing all UEs to establish emergency bearers (i.e. indicating that the network behaviour of the first network includes behaviour D), then if the first message includes identification information of the first UE, or the second UE has obtained the identification information of the first UE, the second UE may or may not provide relay services of emergency services for the first UE. At this time, the identification information of the first UE may include one or more of the following: IMSI, SUPI, GUTI, IMEI, or, 5G-GUTI.

Or the second information indicates that the first network does not require IMS registration to be performed, the third information indicates that the network behavior of the first network includes allowing only UEs having identification information to establish emergency bearers (i.e., indicates that the network behavior of the first network includes behavior C), and the first message includes the identification information of the first UE, or the second UE has obtained the identification information of the first UE, the second UE may provide relay services of emergency services for the first UE. At this time, the identification information of the first UE may include one or more of the following: IMSI, SUPI, GUTI, or, 5G-GUTI.

Or the second information indicates that the first network requires IMS registration to be performed, the third information indicates that the network behavior of the first network includes allowing only the UE having the identification information to establish an emergency bearer (i.e., indicates that the network behavior of the first network includes behavior C), and the first message includes the identification information of the first UE, or the second UE has obtained the identification information of the first UE, the second UE may or may not provide a relay service of the emergency service for the first UE. At this time, the identification information of the first UE may include one or more of the following: IMSI, SUPI, GUTI, or, 5G-GUTI.

Or the second information indicates that the first network requires or does not require IMS registration, the third information indicates that the network behavior of the first network includes allowing only UEs having a valid subscription to establish an emergency bearer (i.e., indicates that the network behavior of the first network includes behavior B), or includes allowing only UEs having a valid subscription and successfully registering with the network to establish an emergency bearer (i.e., indicates that the network behavior of the first network includes behavior a), the second UE may not provide a relay service of emergency services for the first UE, whether the first message includes identification information of the first UE, or whether the second UE has obtained the identification information of the first UE.

Or the second information indicates that the first network requires or does not require IMS registration, the second UE may not provide relay services for emergency services for the first UE, regardless of what the third information indicates the network behavior of the first network, if the first message does not include any identification information of the first UE and the second UE does not obtain any identification information of the first UE.

Or the second information indicates that the first network requires or does not require IMS registration, the second UE may not provide relay services for emergency services for the first UE if the first message includes a device identity (e.g., IMEI) of the first UE and does not include other identities of the first UE, and/or the second UE has obtained the device identity of the first UE and does not obtain other identities of the first UE, and the third information indicates that the network behavior of the first network includes one or more of behavior a, behavior B, or behavior C (or the third information indicates that the network behavior of the first network is not behavior B).

Wherein if the HPLMN of the first UE has an intersection with the first network, e.g. the number of intersection networks is one or more, the first UE has a valid subscription to the first network and also has a valid IMS certificate of the first network, so the first UE is able to perform emergency services within the intersection networks by the second UE. Thus, alternatively, if the HPLMN of the first UE has an intersection with the first network, the second UE may not have to perform S702, but may perform S703.

Or if the HPLMN of the first UE does not intersect the first network, indicating that the first UE is roaming to the first network. In this case, the second UE may determine whether to accept the request of the first UE through a corresponding judgment process, i.e., the second UE may perform S702. For a description of whether the HPLMN of the first UE has an intersection with the first network, reference may be made to the embodiment shown in fig. 6.

Or even if the HPLMN of the first UE has an intersection with the first network, the second UE may perform S702, in which case the second UE may not have to determine whether the HPLMN of the first UE has an intersection with the first network.

Optionally, the method further includes S706, where the second UE sends a second message to the first UE. Accordingly, the second UE receives a second message from the first UE. The second message may indicate a relay service providing the emergency service.

For example, if the second UE determines that the relay service of the emergency service can be provided to the first UE according to the judgment of S702, the second UE may perform S706.

Or if the second UE determines that the relay service of the emergency service cannot be provided to the first UE according to the judgment of S702, the second UE may not perform S706. If the first UE does not receive the second message from the second UE, it may be determined that the second UE cannot provide the relay service of the emergency service for the first UE.

Or if the second UE determines that the relay service of the emergency service can be provided to the first UE according to the determination of S702, the second UE may perform S707 instead of S706, and the second UE sends a third message to the first UE, and correspondingly, the second UE receives the third message from the first UE. The third message may refuse to provide (or not provide) a relay service of the emergency service.

Optionally, the third message may include a corresponding cause value (cause). For example, the third message may include a first cause value, which may indicate that the first network requires IMS registration to be performed, and/or a second cause value, which may indicate that the first network does not allow all UEs to establish emergency bearers. For example, if the second UE determines that the first UE provides a relay service for emergency services according to the second information, the third message may include a first cause value; the third message may include a second cause value if the second UE determines that the first UE provides a relay service for emergency services according to the third information. The first UE obtains the cause value and knows the reason for rejection by the second UE.

For example, with model A in embodiments of the present application, the second UE may broadcast a discovery announce message that may be used to indicate relay services that provide emergency services. After receiving the discovery announcement message, the first UE may send a connection establishment request message to the second UE, where the connection establishment request message may be used as a first message for requesting establishment of a connection for relaying emergency services. In this case, the second message may be a connection establishment acceptance message and the third message may be a connection establishment rejection message. That is, after the second UE receives the connection establishment request message, if it is determined that the connection for relaying the emergency service can be established with the first UE, a connection establishment acceptance message may be transmitted to the first UE as the second message, and if it is determined that the connection for relaying the emergency service cannot be established with the first UE, a connection establishment rejection message may be transmitted to the first UE as the third message.

For another example, the embodiment of the present application employs model B. The first UE broadcasts a discovery request message, which may be used to request a relay providing an emergency service (e.g., the discovery request message includes an RSC corresponding to the emergency service), first as the first message. In this case, the second message may be a discovery accept message and the third message may be a discovery reject message. That is, after the second UE receives the discovery request message, if it is determined that the relay service of the emergency service can be provided to the first UE, the discovery accept message as the second message may be transmitted to the first UE; or if the second UE determines that the relay service of the emergency service cannot be provided to the first UE, a discovery reject message may be transmitted to the first UE as a third message. For example, if the second UE determines that the RSC included in the discovery request message matches the RSC of the relay service that the second UE can provide, it indicates that the second UE can provide the relay service of the emergency service for the first UE, and if it determines that the RSC included in the discovery request message does not match the RSC of the relay service that the second UE can provide, it indicates that the second UE cannot provide the relay service of the emergency service for the first UE. In this manner, model B is employed, the first message and the second message relate to a discovery procedure between the first UE and the second UE. For another example, in the embodiment of the present application, the model B is used, and the first UE may send a connection establishment request message to the second UE, where the connection establishment request message may be used as the first message to request to establish a connection for relaying the emergency service. Alternatively, the first UE and the second UE may undergo a discovery procedure before this. For example, the first UE first broadcasts a discovery request message, which may be used to indicate discovery of a relay providing emergency services. After receiving the discovery request message, the second UE may send a discovery accept message to the first UE if it is determined that the relay service for the emergency service can be provided for the first UE, the discovery accept message indicating the relay service for the emergency service. After receiving the discovery accept message, the first UE may send a connection establishment request message as a first message to the second UE. In this case, the second message may be a connection establishment acceptance message and the third message may be a connection establishment rejection message. That is, after the second UE receives the connection establishment request message, if it is determined that the connection for relaying the emergency service can be established with the first UE, a connection establishment acceptance message may be transmitted to the first UE as the second message, and if it is determined that the connection for relaying the emergency service cannot be established with the first UE, a connection establishment rejection message may be transmitted to the first UE as the third message. In this manner, using model B, the first message and the second message relate to a connection establishment procedure between the first UE and the second UE.

As another example, embodiments of the present application employ a combination of model A and model B. The first UE broadcasts a discovery request message, which may be used to request a relay providing an emergency service (e.g., the discovery request message includes an RSC corresponding to the emergency service), first as the first message. In this case, the second message or the third message may be a discovery announcement message. That is, after receiving the discovery request message, the second UE may transmit a discovery announce message, which may be transmitted in a broadcast or unicast manner. Wherein the discovery announce message may be the second message if the second UE determines a relay service capable of providing emergency services to the first UE; or if the second UE determines that relay service for emergency services cannot be provided to the first UE, the discovery announce message may be the third message.

Wherein the emergency service may be performed within the first network by the second UE if the first UE receives the second message. Or if the first UE receives the third message, the first UE may not select a relay service for providing emergency services by the second UE and/or the first network. For example, the first UE may give up executing the emergency service, or the first UE may reselect the relay UE and/or the network to provide the relay service of the emergency service, so as to reduce the time delay of executing the emergency service and improve the success rate of executing the emergency service.

Alternatively, the second UE may download to perform S702 in case it is determined that the emergency RSC exists, and if the emergency RSC does not exist, the second UE may not need to determine whether to provide the relay service of the emergency service for the first UE according to the first information. For example, one way in which an emergency RSC exists is that the first message includes an emergency RSC; or alternatively, the first message includes an emergency RSC, and the emergency RSC matches an emergency RSC that the second UE is able to provide.

In the embodiment of the application, the first UE can select the proper UE and/or network to provide the relay service of the emergency service through the judgment of the second UE, so that the success rate of the first UE for executing the emergency service is improved, and the safety risk is reduced.

Both the embodiment shown in fig. 6 and the embodiment shown in fig. 7 are concerned with relay scenarios. Besides the relay scenario, there is also a problem that the success rate of the UE making an emergency call is low in the direct connection scenario. The third communication method provided by the embodiment of the application can improve the success rate of executing the emergency service by the UE in the direct-connection scenario. The method provided by the embodiment of the present application may be applied to the network architecture shown in fig. 2, for example, the UE involved in the method provided by the embodiment of the present application may be the UE in fig. 2. Please refer to fig. 8, which is a flowchart of the method.

S801, the UE determines that the HPLMN of the UE cannot be searched. For example, during the process of searching the network, the UE cannot search for the HPLMN of the UE.

S802, the UE selects a network according to the first information.

Wherein the first information may include information whether the at least one network requires IMS registration to be performed (e.g., the first information includes information whether each of the at least one network requires IMS registration to be performed), and/or the first information may include network behavior information for the at least one network to establish an emergency bearer (e.g., the first information includes network behavior information for each of the at least one network to establish an emergency bearer). Alternatively, the first information may include second information and/or third information, for example, the second information includes information whether the at least one network requires IMS registration to be performed (for example, the second information includes information whether each of the at least one network requires IMS registration to be performed), and the third information may include network behavior information for the at least one network to establish an emergency bearer (for example, the third information includes network behavior information for each of the at least one network to establish an emergency bearer). For more description of the first information, the second information, the third information, etc., reference is made to the embodiment shown in fig. 6.

Alternatively, the UE may first obtain the first information. For example, the first network device may send the first configuration information to the UE, for which reference may be made to S803 in fig. 8. Wherein S803 may occur before S802 or before S801, fig. 8 exemplifies that S803 occurs before S801. The first configuration information may include information whether the at least one network requires IMS registration to be performed and/or network behavior information that includes the at least one network establishing emergency bearers, wherein the at least one network is a network to which the UE is authorized to access, e.g., a PLMN to which the UE is authorized to access. The UE may obtain the first information according to the first configuration information. For more description of this section, for example, the first network device and the first configuration information, etc., reference may be made to the embodiment shown in fig. 6.

The foregoing describes that the first information includes the second information and/or the third information, and the manner in which the UE performs S802 may also be different when the information included in the first information is different, which is described by way of example below.

1. The first information includes second information. The UE may select a network according to the second information in S802.

For example, if the second information indicates that the first network does not require IMS registration, the UE may select the first network.

Or if the second information indicates that the first network requires IMS registration to be performed and the UE has an IMS certificate for the first network (or the UE has an IMS certificate for the IMS to which the first network corresponds), the UE may select the first network.

Or if the second information indicates that the first network requires IMS registration to be performed and the UE does not have an IMS certificate for the first network, the UE may not select the first network.

Wherein the UE has an IMS certificate of the first network, which may be understood as the UE having a valid IMS certificate of the first network; the UE does not have an IMS certificate of the first network, which is understood to mean that the UE does not have a valid IMS certificate of the first network. Alternatively, if the first network is the HPLMN of the UE, the UE may have a valid IMS certificate of the first network (but in an embodiment of the application, the first network is not the HPLMN of the UE). Or although the first network is not the HPLMN of the UE, but the first network is the network to which the UE is authorized to access, the first network can interact with the HPLMN of the UE to obtain the IMS certificate, although the IMS certificate possessed by the UE may not be the IMS certificate of the first network (e.g., the IMS certificate of the HPLMN of the UE), and thus the UE may also be considered to have a valid IMS certificate of the first network. Or, although the first network is not the HPLMN of the UE, the first network is able to verify the IMS credentials of the UE, e.g. the IMS of the first network has interworking capability with the IMS of the HPLMN of the UE, so the UE is also considered to have valid IMS credentials of the first network. If the first network is not the HPLMN of the UE, and the first network is not the network to which the UE is authorized to access, and the first network is also unable to verify the IMS credentials of the UE (e.g., the IMS of the first network has no interworking capability with the IMS corresponding to the HPLMN of the UE), then the UE is deemed to have no valid IMS credentials for the first network. For more description of this content reference is made to the embodiment shown in fig. 6.

2. The first information includes third information. The UE may select a network according to the third information in S802.

The UE may select the first network if the UE determines that the emergency bearer can be established in the first network according to the third information. Or if the UE determines that the emergency bearer cannot be established in the first network according to the third information, the UE may not select the first network.

For example, the third information indicates that the network behavior of the first network includes allowing all UEs to establish an emergency bearer (i.e., the network behavior of the first network includes behavior D), the UE can establish the emergency bearer in the first network as long as the UE has the identification information, and the first network can be selected. The identification information is, for example, a device identification of the UE, such as IMEI, etc.

Or the third information indicates that the network behavior of the first network includes allowing only UEs having the identification information to establish emergency bearers (i.e., indicates that the network behavior of the first network includes behavior C). Then, if the UE has identification information, the UE can establish an emergency bearer at the first network, which can be selected. The identification information includes, for example, one or more of IMSI, SUPI, GUTI, or 5G-GUTI for the UE. Or the UE is considered to have identification information as long as the UE has a communication module such as SIM, USIM, or eSIM.

Or the third information indicates that the network behaviour of the first network comprises allowing only UEs with a valid subscription to establish emergency bearers (i.e. indicates that the network behaviour of the first network comprises behaviour B). Then, if the UE has a valid subscription with the first network, the UE is able to establish an emergency bearer with the first network, the first network may be selected; and if the UE does not have a valid subscription in the first network, the UE cannot establish an emergency bearer in the first network and may not select the first network.

Or the third information indicates that the network behavior of the first network includes allowing only UEs having a valid subscription and successfully registering with the network to establish an emergency bearer (i.e., indicates that the network behavior of the first network includes behavior a). Then, if the UE has a valid subscription with the first network and the UE is not in a limited service state, the UE is able to establish an emergency bearer with the first network, which may be selected; or if the UE does not have a valid subscription in the first network and/or the UE is in a limited service state, the UE may not be able to establish an emergency bearer in the first network and may not select the first network.

With respect to whether the UE has relevant content for a valid subscription within the first network, reference may be made to the embodiment shown in fig. 6.

3. The first information includes second information and third information. The UE may select a network according to the second information and the third information in S802. In this case, the UE may select the first network when the first network satisfies both the second information and the third information; and the UE may not select the first network if the first network does not satisfy the second information and/or does not satisfy the third information.

For example, the second information indicates that the first network does not require IMS registration to be performed, and the UE determines that an emergency bearer can be established at the first network according to the third information, the UE may select the first network.

Or the second information indicates that the first network does not require IMS registration, and the UE determines that an emergency bearer cannot be established in the first network according to the third information, the UE may not select the first network.

Or the second information indicates that the first network requires IMS registration, and the UE has an IMS certificate of the first network, and the UE determines that an emergency bearer can be established in the first network according to the third information, the UE may select the first network.

Or the second information indicates that the first network requires IMS registration, and the UE has an IMS certificate of the first network, and the UE determines that an emergency bearer cannot be established in the first network according to the third information, the UE may not select the first network.

Or the second information indicates that the first network requires to execute IMS registration, the UE does not have IMS certificate of the first network, and the UE determines that emergency bearing can be established in the first network according to the third information, the UE does not select the first network;

or the second information indicates that the first network requires to perform IMS registration, and the UE does not have an IMS certificate of the first network, and the UE determines that an emergency bearer cannot be established in the first network according to the third information, the UE may not select the first network.

Wherein the first network belongs to at least one network, it is understood that the UE may select a network among the at least one network according to the above rule. For example, the first network is one of the networks searched by the UE. If the UE does not select the first network, the UE may continue to determine if the searched other network is selected according to the rules as described above. The UE may search for one or more networks (e.g., the first network is one of the networks) during the network search, in such a way that the UE determines whether the searched network can be selected one by one, and once the UE determines that one of the searched networks can be selected, the UE may choose to access the network and no longer determine whether other networks can be selected. Or alternatively, the UE may determine whether it can select for each network searched, and if the UE determines that there are multiple networks to select according to the above rule, the UE may randomly select one network from, or the UE may select one network from among other factors. For example, the UE may select the network with the strongest signal quality among the networks to improve the communication quality of the UE within the network. For another example, the UE has identification information, where the identification information includes one or more of SUPI, IMSI, GUTI or 5G-GUTI, the network behavior of the network 1 searched by the UE is behavior C, the network behavior of the network 2 is behavior D, and both the network 1 and the network 2 are selectable networks by the UE, and the UE may select the network 1 to leave the access opportunity of the network 2 to the non-card UE as much as possible.

In the embodiment of the application, the UE can select a proper network, so that the success rate of the UE for executing the emergency service is improved, and the safety risk is reduced. And the UE can select to access the proper network as much as possible in the network selection stage, thereby reducing the probability that the emergency service cannot be initiated due to the improper network access or reducing the time delay of network reselection due to the improper network access.

Next, a fourth communication method provided by the embodiment of the present application is described, which can also improve the success rate of executing the emergency service by the UE in the direct connection scenario. The method provided by the embodiment of the present application may be applied to the network architecture shown in fig. 2, for example, the UE involved in the method provided by the embodiment of the present application may be the UE in fig. 2. Please refer to fig. 9, which is a flowchart of the method.

S901, the first network sends first information to the UE. Accordingly, the UE receives first information from the first network. For more description of the first information reference is made to the embodiment shown in fig. 6.

Alternatively, the first information may be sent to the UE by a sixth network device within the first network. The sixth network device is for example an AMF or may be another core network device. For example, during registration of the UE with the first network, an AMF within the first network may send first information to the UE, optionally the first information may be included in a registration accept (registration accept) message sent by the AMF to the UE; or after the first network registration is completed, the AMF in the first network may send the first information to the UE. Or the sixth network device may not belong to the first network but may be a device in another network, or a third party server, etc. The sixth network device may directly send the first information to the UE without going through other devices; or the sixth network device may also be a relay device of the first information.

Optionally, the sixth network device may send the first information to the UE if it is determined that the UE is a roaming UE (i.e., the first network is not the HPLMN of the UE) and/or if it is determined that the UE is a relay capable (or authorized to provide relay services); otherwise, the sixth network device may not send the first information to the UE.

S902, the UE determines whether to reselect a network according to the first information.

The foregoing describes that the first information includes the second information and/or the third information, and the manner in which the UE performs S902 may also be different when the information included in the first information is different, which is described by way of example below.

1. The first information includes second information. The UE may determine whether to reselect the network according to the second information in S902.

For example, if the second information indicates that the first network does not require IMS registration, the UE may reselect the network. That is, the UE may not continue to access the first network but reselect network access to perform emergency services.

Or if the second information indicates that the first network requires IMS registration to be performed and the UE has an IMS certificate for the first network (or the UE has an IMS certificate for the IMS to which the first network corresponds), the UE may not reselect the network. That is, the UE may continue to camp on the first network where the UE is able to perform emergency services.

Or if the second information indicates that the first network requires IMS registration to be performed and the UE does not have an IMS certificate for the first network, the UE may reselect the network.

Wherein the UE has an IMS certificate of the first network, which may be understood as the UE having a valid IMS certificate of the first network; the UE does not have an IMS certificate of the first network, which is understood to mean that the UE does not have a valid IMS certificate of the first network. Reference is made to the description of the embodiment shown in fig. 8 as to whether the UE has a valid IMS certificate for the first network.

2. The first information includes third information. The UE may determine whether to reselect the network according to the third information in S902.

The UE may not reselect the network if the UE determines from the third information that an emergency bearer can be established on the first network. Or if the UE determines from the third information that the emergency bearer cannot be established in the first network, the UE may reselect the network.

For example, the third information indicates that the network behavior of the first network includes allowing all UEs to establish an emergency bearer (i.e., indicates that the network behavior of the first network includes behavior D), the UEs can establish the emergency bearer in the first network without reselecting the network as long as they have the identification information. The identification information is, for example, a device identification of the UE, such as IMEI, etc.

Or the third information indicates that the network behavior of the first network includes allowing only UEs having the identification information to establish emergency bearers (i.e., indicates that the network behavior of the first network includes behavior C). Then, if the UE has identification information, the UE is able to establish an emergency bearer in the first network, possibly without reselecting the network; and if the UE does not have the identification information, the UE cannot establish an emergency bearer in the first network and can reselect the network. The identification information includes, for example, one or more of IMSI, SUPI, GUTI, or 5G-GUTI for the UE. Or the UE is considered to have identification information as long as the UE has a communication module such as SIM, USIM, or eSIM.

Or the third information indicates that the network behaviour of the first network comprises allowing only UEs with a valid subscription to establish emergency bearers (i.e. indicates that the network behaviour of the first network comprises behaviour B). Then, if the UE has a valid subscription in the first network, the UE is able to establish an emergency bearer in the first network, possibly without reselecting the network; if the UE does not have a valid subscription in the first network, the UE cannot establish an emergency bearer in the first network and can reselect the network.

Or the third information indicates that the network behavior of the first network includes allowing only UEs having a valid subscription and successfully registering with the network to establish an emergency bearer (i.e., indicates that the network behavior of the first network includes behavior a). Then, if the UE has a valid subscription on the first network and the UE is not in a limited service state, the UE is able to establish an emergency bearer on the first network, possibly without reselecting the network; or if the UE does not have a valid subscription in the first network and/or the UE is in a limited service state, the UE may not be able to establish an emergency bearer in the first network and may reselect the network.

3. The first information includes second information and third information. The UE may determine whether to reselect the network according to the second information and the third information in S902. In this case, the UE may not reselect the network when the first network satisfies both the second information and the third information; and if the first network does not satisfy the second information and/or does not satisfy the third information, the UE may reselect the network.

For example, the second information indicates that the first network does not require IMS registration to be performed, and the UE determines from the third information that an emergency bearer can be established at the first network, the UE may not reselect the network.

Or the second information indicates that the first network does not require IMS registration, and the UE determines that an emergency bearer cannot be established in the first network according to the third information, the UE may reselect the network.

Or the second information indicates that the first network requires IMS registration to be performed, and the UE has an IMS certificate of the first network, and the UE determines that an emergency bearer can be established in the first network according to the third information, the UE may not reselect the network.

Or the second information indicates that the first network requires to perform IMS registration, and the UE has an IMS certificate of the first network, and the UE determines that an emergency bearer cannot be established in the first network according to the third information, the UE may reselect the network.

Or the second information indicates that the first network requires to perform IMS registration, and the UE does not have an IMS certificate of the first network, and the UE determines that an emergency bearer can be established in the first network according to the third information, the UE may reselect the network.

Or the second information indicates that the first network requires to perform IMS registration, the UE does not have an IMS certificate of the first network, and the UE determines that an emergency bearer cannot be established in the first network according to the third information, the UE may reselect the network.

In the embodiment of the application, the UE can select a proper network, so that the success rate of the UE for executing the emergency service is improved, and the safety risk is reduced.

Fig. 10 is a schematic structural diagram of a communication device according to an embodiment of the present application. The communication device 1000 may be the first UE or the circuitry of the first UE according to any of the embodiments shown in fig. 6 to 7, for implementing the method corresponding to the first UE in the above method embodiments. Or the communication device 1000 may be the second UE or the circuitry of the second UE according to any one of the embodiments shown in fig. 6 to fig. 7, for implementing the method corresponding to the second UE in the above method embodiment. Or the communication device 1000 may be a UE or circuitry of the UE according to any one of the embodiments shown in fig. 8 to fig. 9, for implementing a method corresponding to the UE in the above method embodiments. Specific functions can be seen from the description of the method embodiments described above. One type of circuitry is, for example, a chip system.

The communication device 1000 comprises at least one processor 1001. The processor 1001 may be used for internal processing of the device, implementing certain control processing functions. Optionally, the processor 1001 includes instructions. Alternatively, the processor 1001 may store data. Alternatively, the different processors may be separate devices, may be located in different physical locations, and may be located on different integrated circuits. Alternatively, the different processors may be integrated in one or more processors, e.g., integrated on one or more integrated circuits.

Optionally, the communications device 1000 includes one or more memories 1003 for storing instructions. Optionally, the memory 1003 may also store data therein. The processor and the memory may be provided separately or may be integrated.

Optionally, the communication device 1000 includes a communication line 1002, and at least one communication interface 1004. Among them, since the memory 1003, the communication line 1002, and the communication interface 1004 are optional, they are all indicated by broken lines in fig. 10.

Optionally, the communication device 1000 may also include a transceiver and/or an antenna. Wherein the transceiver may be used to transmit information to or receive information from other devices. The transceiver may be referred to as a transceiver, a transceiver circuit, an input-output interface, etc. for implementing the transceiver function of the communication device 1000 via an antenna. Optionally, the transceiver comprises a transmitter (transmitter) and a receiver (receiver). Illustratively, a transmitter may be used to generate a radio frequency (radio frequency) signal from the baseband signal, and a receiver may be used to convert the radio frequency signal to the baseband signal.

The processor 1001 may include a general purpose central processing unit (central processing unit, CPU), microprocessor, application SPECIFIC INTEGRATED Circuit (ASIC), or one or more integrated circuits for controlling the execution of the program of the present application.

Communication line 1002 may include a pathway to transfer information between the aforementioned components.

Communication interface 1004, means such as any transceiver used to communicate with other devices or communication networks, such as ethernet, radio access network (radio access network, RAN), wireless local area network (wireless local area networks, WLAN), wired access network, etc.

The memory 1003 may be, but is not limited to, a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (random access memory, RAM) or other type of dynamic storage device that can store information and instructions, or an electrically erasable programmable read-only memory (ELECTRICALLY ERASABLE PROGRAMMABLE READ-only memory, EEPROM), a compact disc read-only memory (compact disc read-only memory) or other optical disc storage, a compact disc storage (including compact disc, laser disc, optical disc, digital versatile disc, blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. The memory 1003 may be separate and coupled to the processor 1001 by communication lines 1002. Or the memory 1003 may be integral to the processor 1001.

The memory 1003 is used for storing computer-executable instructions for executing the present application, and is controlled to be executed by the processor 1001. The processor 1001 is configured to execute computer-executable instructions stored in the memory 1003, thereby implementing the communication method provided by the above-described embodiment of the present application.

Alternatively, the computer-executable instructions in the embodiments of the present application may be referred to as application program codes, which are not particularly limited in the embodiments of the present application.

In a particular implementation, the processor 1001 may include one or more CPUs, such as CPU0 and CPU1 in fig. 10, as one embodiment.

In a particular implementation, as one embodiment, the communications device 1000 may include multiple processors, such as processor 1001 and processor 1005 in FIG. 10. Each of these processors may be a single-core (single-CPU) processor or may be a multi-core (multi-CPU) processor. A processor herein may refer to one or more devices, circuits, and/or processing cores for processing data (e.g., computer program instructions).

When the apparatus shown in fig. 10 is a chip, for example, a chip of a first UE, or a chip of a second UE, or a chip of a UE, the chip includes a processor 1001 (may further include a processor 1005), a communication line 1002, a memory 1003, and a communication interface 1004. In particular, the communication interface 1004 may be an input interface, a pin, or a circuit, etc. Memory 1003 may be a register, cache, or the like. Processor 1001 and processor 1005 may be a general purpose CPU, microprocessor, ASIC, or one or more integrated circuits configured to control the execution of the programs of the communication method of any of the embodiments described above.

The embodiment of the application can divide the functional modules of the device according to the method example, for example, each functional module can be divided corresponding to each function, and two or more functions can be integrated in one processing module. The integrated modules may be implemented in hardware or in software functional modules. It should be noted that, in the embodiment of the present application, the division of the modules is schematic, which is merely a logic function division, and other division manners may be implemented in actual implementation. For example, in the case of dividing the respective functional modules by the respective functions, fig. 11 shows a schematic diagram of an apparatus, and the apparatus 1100 may be the first UE or the second UE or the UE, or a chip in the first UE or a chip in the second UE or a chip in the UE, which are involved in the respective method embodiments described above. The apparatus 1100 comprises a transmitting unit 1101, a processing unit 1102 and a receiving unit 1103.

It should be understood that the apparatus 1100 may be used to implement the steps performed by the first UE or the second UE or the UE in the method according to the embodiments of the present application, and the relevant features may refer to the foregoing embodiments, which are not described herein.

Alternatively, the functions/implementation procedures of the transmitting unit 1101, the receiving unit 1103, and the processing unit 1102 in fig. 11 may be implemented by the processor 1001 in fig. 10 calling computer-executable instructions stored in the memory 1003. Or the function/implementation procedure of the processing unit 1102 in fig. 11 may be implemented by the processor 1001 in fig. 10 calling computer-executable instructions stored in the memory 1003, and the function/implementation procedure of the transmitting unit 1101 and the receiving unit 1103 in fig. 11 may be implemented by the communication interface 1004 in fig. 10.

Alternatively, when the apparatus 1100 is a chip or a circuit, the functions/implementation procedures of the transmitting unit 1101 and the receiving unit 1103 may also be implemented by pins or circuits, or the like.

The present application also provides a computer readable storage medium storing a computer program or instructions which, when executed, implement a method performed by a first UE or a second UE or UE in the foregoing method embodiments. Thus, the functions described in the above embodiments may be implemented in the form of software functional units and sold or used as independent products. Based on such understanding, the technical solution of the present application may be embodied in essence or contributing part or part of the technical solution in the form of a software product stored in a storage medium, comprising several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present application. The storage medium includes: a usb disk, a removable hard disk, a ROM, a RAM, a magnetic disk, or an optical disk, etc.

The present application also provides a computer program product comprising: computer program code which, when run on a computer, causes the computer to perform the method performed by the first UE or the second UE or the UE in any of the method embodiments described above.

The embodiment of the application also provides a processing device, which comprises a processor and an interface; the processor is configured to perform a method performed by the first UE or the second UE or the UE according to any of the method embodiments described above.

In the above embodiments, it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loaded and executed on a computer, produces a flow or function in accordance with embodiments of the present application, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. The computer instructions may be stored in or transmitted from one computer-readable storage medium to another, for example, by wired (e.g., coaxial cable, optical fiber, digital Subscriber Line (DSL)), or wireless (e.g., infrared, wireless, microwave, etc.). The computer readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that contains an integration of one or more available media. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid State Drive (SSD)), etc.

The various illustrative logical blocks and circuits described in connection with the embodiments of the present application may be implemented or performed with a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the general purpose processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a digital signal processor and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a digital signal processor core, or any other similar configuration.

The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software unit executed by a processor, or in a combination of the two. The software elements may be stored in RAM, flash memory, ROM, erasable programmable read-only memory (EPROM), EEPROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. In an example, a storage medium may be coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC, which may reside in a terminal device. In the alternative, the processor and the storage medium may reside in different components in a terminal device.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

Although the embodiments of the present application have been described in connection with specific features and embodiments thereof, it will be apparent that various modifications and combinations thereof can be made without departing from the scope of the embodiments of the application. Accordingly, the present embodiments and figures are merely exemplary illustrations of embodiments of the application defined by the appended claims and are considered to cover any and all modifications, variations, combinations, or equivalents of the embodiments that fall within the scope of the embodiments of the application. It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments of the present application without departing from the scope of the embodiments of the application. Thus, the embodiments of the present application are intended to include such modifications and alterations insofar as they come within the scope of the embodiments of the application as claimed and the equivalents thereof.

Claims

1. A communication method, applied to a first terminal device, the method comprising:

Receiving a first message from a second terminal device, wherein the first message is used for indicating a relay service for providing emergency services;

And determining whether to select the second terminal equipment and/or the first network to provide the relay service of the emergency service according to first information, wherein the first information comprises information whether the first network requires to execute IMS registration of an Internet protocol multimedia subsystem and/or comprises network behavior information of the first network for establishing emergency bearing.

2. The method of claim 1, wherein the first network is a serving network of the second terminal device or the first network is a network accessible to a serving cell of the second terminal device.

3. The method according to claim 1 or 2, wherein the first message is a discovery message or a response message to a connection establishment request message.

4. A method according to any of claims 1-3, characterized in that determining whether to select the relay service of the emergency service provided by the second terminal device and/or the first network based on the first information comprises:

When the first terminal equipment is far-end terminal equipment of a layer 3 type, determining whether to select the second terminal equipment to provide relay service of the emergency service according to the first information; or alternatively

When the first terminal equipment is far-end terminal equipment of a layer 2 type, determining whether to select the first network to provide relay service of the emergency service according to the first information; or alternatively

And when the first terminal equipment is far-end terminal equipment of a layer 2 type, determining whether to select the second terminal equipment and the first network to provide relay service of the emergency service according to the first information.

5. The method according to any one of claims 1 to 4, further comprising:

Receiving first configuration information from a first network device, wherein the first configuration information comprises information about whether a second network requires IMS registration to be performed and/or network behavior information for establishing an emergency bearer, the second network comprises a network which is authorized to be accessed by the first terminal device, and the second network comprises the first network; or alternatively, the first and second heat exchangers may be,

Receiving second configuration information from a second network device, wherein the second configuration information comprises information about whether a third network requires IMS registration to be performed and/or network behavior information for establishing an emergency bearer, the third network comprises a network in which the first terminal device is authorized to use a relay service, and the third network comprises the first network; or alternatively, the first and second heat exchangers may be,

The first message includes the first information.

6. The method according to any of claims 1-5, characterized in that before determining from the first information whether to select the relay service of the emergency service provided by the second terminal device and/or the first network, the method further comprises:

determining that the first network is different from a home network of the first terminal device.

7. The method according to any of claims 1-6, wherein the first information comprises second information, the second information comprising information whether the first network requires performing IMS registration, determining whether to select the second terminal device and/or the first network to provide relay services for the emergency service based on the first information, comprising one or more of:

Selecting a relay service for the second terminal device and/or the first network to provide the emergency service when the second information indicates that the first network does not require IMS registration; or alternatively

Selecting a relay service for providing the emergency service by the second terminal device and/or the first network when the second information indicates that the first network requires to perform IMS registration and the first terminal device has an IMS certificate of the first network; or alternatively

When the second information indicates that the first network requires to perform IMS registration and the first terminal device does not have an IMS certificate of the first network, a relay service for the emergency service provided by the second terminal device and/or the first network is not selected.

8. The method according to claim 7, wherein the first terminal device has an IMS certificate of the first network, comprising:

the first network is a home network of the first terminal equipment; or alternatively

The first network is different from a home network of the first terminal device, and the first network is a network to which the first terminal device is authorized to access or a network to which the first terminal device is authorized to use a relay service; or alternatively

The first network is different from a home network of the first terminal device and the first network is capable of verifying an IMS certificate of the first terminal device.

9. The method according to any of claims 1-6, wherein the first information comprises third information, the third information comprising network behavior information for the first network to establish an emergency bearer, determining whether to select the second terminal device and/or the first network to provide relay services for the emergency service based on the first information, comprising one or more of:

Selecting a relay service of the second terminal device and/or the first network to provide the emergency service when it is determined that an emergency bearer can be established in the first network according to the third information; or alternatively

And when the emergency bearer can not be established in the first network according to the third information, not selecting the second terminal equipment and/or the first network to provide the relay service of the emergency service.

10. The method according to any of claims 1-6, wherein the first information comprises second information and third information, the second information comprises information whether the first network requires IMS registration to be performed, the third information comprises network behavior information for the first network to establish an emergency bearer, and determining whether to select the second terminal device and/or the first network to provide a relay service for the emergency service according to the first information comprises one or more of:

selecting a relay service of the second terminal device and/or the first network to provide the emergency service when the second information indicates that the first network does not require IMS registration, and the emergency bearer can be established in the first network according to the third information; or alternatively

When the second information indicates that the first network does not require IMS registration, and the first network cannot establish emergency bearing according to the third information, the second terminal equipment and/or the first network are/is not selected to provide relay service of the emergency service; or alternatively

When the second information indicates that the first network requires to execute IMS registration, the first terminal equipment has an IMS certificate of the first network, and the first terminal equipment and/or the first network can be selected to provide relay service of the emergency service when the emergency bearer can be established in the first network according to the third information; or alternatively

When the second information indicates that the first network requires to execute IMS registration and the first terminal equipment has an IMS certificate of the first network, and the first terminal equipment and/or the first network are/is not selected to provide relay service of the emergency service when the first network can not establish emergency bearer according to the third information; or alternatively

When the second information indicates that the first network requires to execute IMS registration and the first terminal equipment does not have an IMS certificate of the first network, and the emergency bearer can be established in the first network according to the third information, the relay service of the emergency service provided by the second terminal equipment and/or the first network is not selected; or alternatively

And when the second information indicates that the first network requires to execute IMS registration and the first terminal equipment does not have IMS certificate of the first network, and the emergency bearer can not be established in the first network according to the third information, the relay service of the emergency service provided by the second terminal equipment and/or the first network is not selected.

11. The method according to any of claims 1-6, 9 or 10, wherein the network behavior of the first network to establish an emergency bearer comprises one or more of:

only the terminal equipment with valid subscription and successful registration network is allowed to establish emergency bearer;

only the terminal equipment with valid subscription is allowed to establish emergency bearer;

Only the terminal equipment with the identification information is allowed to establish emergency bearing; or alternatively, the first and second heat exchangers may be,

Allowing all terminal devices to establish an emergency bearer.

12. The method according to any of claims 9-11, wherein determining that an emergency bearer can be established at the first network based on the third information comprises one or more of:

Determining that an emergency bearer can be established on the first network when the third information indicates that the network behavior of the first network includes allowing all terminal devices to establish an emergency bearer; or alternatively

Determining that an emergency bearer can be established on the first network when the third information indicates that the network behavior of the first network includes allowing only a terminal device having identification information to establish an emergency bearer and the first terminal device has identification information; or alternatively

Determining that an emergency bearer can be established on the first network when the third information indicates that the network behavior of the first network includes allowing only terminal devices having a valid subscription to establish an emergency bearer and the first terminal devices have a valid subscription to the first network; or alternatively

When the third information indicates that the network behavior of the first network includes allowing only a terminal device having a valid subscription and successfully registering with a network to establish an emergency bearer, and the first terminal device has a valid subscription of the first network, and the first terminal device is not in a limited service state, determining that an emergency bearer can be established in the first network.

13. The method of claim 12, wherein the first terminal device has an active subscription to the first network, comprising:

The first network is different from a home network of the first terminal device, and the first network is a network to which the first terminal device is authorized to access or a network to which the first terminal device is authorized to use a relay service.

14. The method according to any one of claims 1 to 13, wherein the first message is used for indicating a relay service providing emergency services, comprising:

the first message comprises a first service code, and the first service code is a service code corresponding to the emergency service.

15. A communication method, applied to a second terminal device, the method comprising:

Acquiring first information, wherein the first information comprises information whether a first network requires IMS registration to be executed or not, and/or network behavior information of the first network for establishing emergency bearing, and the first network is a service network of the second terminal equipment;

And sending a first message to the first terminal equipment, wherein the first message comprises the first information, and the first message is also used for indicating a relay service for providing emergency services.

16. The method of claim 15, wherein the first network is a serving network of the second terminal device or the first network is a network accessible to a serving cell of the second terminal device.

17. The method according to claim 15 or 16, wherein the first message is a discovery message or a response message to a connection establishment request message.

18. The method of any of claims 15-17, wherein obtaining the first information comprises:

Receiving third configuration information from a fourth network device, wherein the third configuration information comprises information about whether the fourth network requires IMS registration to be performed and/or network behavior information for establishing an emergency bearer, the fourth network comprises a network which the second terminal device is authorized to access, and the fourth network comprises the first network; or alternatively, the first and second heat exchangers may be,

Receiving fourth configuration information from a fifth network device, wherein the fourth configuration information comprises information about whether a fifth network requires IMS registration to be performed and/or network behavior information for establishing an emergency bearer, the fifth network comprises a network in which the second terminal device is authorized to provide relay services, and the fifth network comprises the first network; or alternatively, the first and second heat exchangers may be,

The first information is received from a third network device.

19. The method of claim 18, wherein receiving the first information from a third network device comprises:

The first information from the third network device is received during or after registration with the first network.

20. The method according to any of claims 15-19, characterized in that before sending the first discovery message to the first terminal device, the method further comprises:

and receiving a second message from the first terminal equipment, wherein the second message comprises a second service code, and the second service code is used for requesting relay service for providing emergency services.

21. The method according to any of claims 15-20, wherein the second terminal device is a layer 3 type relay terminal device or a layer 2 type relay terminal device.

22. The method of claim 21, wherein the step of determining the position of the probe is performed,

When the second terminal equipment is relay terminal equipment of a layer 3 type, the first information comprises information whether the first network requires to execute IMS registration or not, and does not comprise network behavior information of the first network for establishing emergency bearing; or alternatively

When the second terminal device is a layer 2 type relay terminal device, the first information includes information whether the first network requires IMS registration to be performed, and includes network behavior information that the first network establishes an emergency bearer.

23. The method according to any of claims 15-22, wherein the network behavior of the first network to establish an emergency bearer comprises one or more of:

Allowing all terminal devices to establish an emergency bearer.

24. The method according to any one of claims 15 to 23, wherein the first message is used for indicating a relay service providing emergency services, comprising:

25. A communication method, applied to a second terminal device, the method comprising:

receiving a first message from a first terminal device, wherein the first message is used for requesting relay service of emergency service;

Determining whether to provide relay service of the emergency service for the first terminal equipment according to first information, wherein the first information comprises information whether the first network requires to execute IMS registration or not and/or network behavior information of the first network for establishing emergency bearing;

and sending a second message to the first terminal equipment, wherein the second message is used for indicating a relay service for providing the emergency service.

26. The method of claim 25, wherein the first network is a serving network of the second terminal device or the first network is a network accessible to a serving cell of the second terminal device.

27. The method according to claim 25 or 26, wherein the first message further comprises information of a home network of the first terminal device.

28. The method according to any of claims 25-27, wherein the first message further comprises identification information of the first terminal device.

29. The method according to any of claims 25-28, characterized in that before determining from the first information whether to provide relay services of the emergency service for the first terminal device, the method further comprises:

determining that the home network of the first terminal device is different from the first network.

30. The method according to any of claims 25-29, wherein the first information comprises second information, the second information comprising information whether the first network requires performing IMS registration, determining whether to provide relay services for the emergency services for the first terminal device based on the first information, comprising one or more of:

determining to provide the relay service of the emergency service for the first terminal device when the second information indicates that the first network does not require IMS registration; or alternatively

Determining to provide the relay service of the emergency service for the first terminal device when the second information indicates that the first network requires to perform IMS registration; or alternatively

And when the second information indicates that the first network requires to execute IMS registration, determining that the relay service of the emergency service is not provided for the first terminal equipment.

31. The method according to any one of claims 25-30, wherein after determining that the relay service of the emergency service is not provided for the first terminal device, the method further comprises:

and sending a third message to the first terminal equipment, wherein the third message is used for rejecting the relay service providing the emergency service.

32. The method of claim 31, wherein the third message includes a first cause value indicating that the first network requires IMS registration to be performed.

33. The method according to claim 31 or 32, wherein the third message comprises a second cause value for indicating that the first network does not allow all terminal devices to establish an emergency bearer.

34. The method according to any one of claims 25 to 33, further comprising:

Receiving third configuration information from fourth network equipment, wherein the first configuration information comprises information of whether the fourth network requires IMS registration to be executed and/or network behavior information for establishing emergency bearer, the fourth network comprises a network which the second terminal equipment is authorized to access, and the fourth network comprises the first network; or alternatively, the first and second heat exchangers may be,

Receiving fourth configuration information from a fifth network device, wherein the fourth configuration information comprises information about whether the fifth network requires IMS registration to be performed and/or network behavior information for establishing an emergency bearer, the fifth network comprises a network authorized by the second terminal device to serve as a relay terminal device, and the fifth network comprises the first network; or alternatively, the first and second heat exchangers may be,

The first information is received from a third network device.

35. The method according to any of claims 25-34, wherein the first message is a discovery request message or a connection establishment request message.

36. The method according to any one of claims 25 to 35, wherein,

The first message is the discovery request message, and the second message is a discovery response message or a discovery announce message; or alternatively

The first message is the connection establishment request message, and the second message is a connection establishment response message; or alternatively

The first message is the connection establishment request message, and the third message is a connection establishment rejection message.

37. The method according to any of claims 25-36, wherein the second terminal device is a layer 3 type relay terminal device or a layer 2 type relay terminal device.

38. A communication method, applied to a first terminal device, the method comprising:

transmitting a first message for requesting a relay service of an emergency service;

A second message or a third message from the second terminal device is received, the second message being used to indicate a relay service providing the emergency service, and the third message being used to reject the relay service providing the emergency service.

39. The method of claim 38, wherein the first message further comprises information of a home network of the first terminal device.

40. The method according to claim 38 or 39, wherein the first message further comprises identification information of the first terminal device.

41. The method of any one of claims 38 to 40, wherein the third message includes a first cause value indicating that the first network requires IMS registration to be performed.

42. The method according to any of claims 38-41, wherein the third message comprises a second cause value indicating that the first network does not allow all terminal devices to establish an emergency bearer.

43. The method of any one of claims 38 to 42, wherein after receiving the third message from the second terminal device, the method further comprises:

and not selecting the relay service of the second terminal equipment for executing the emergency service and/or not selecting the service network of the second terminal equipment.

44. The method according to any one of claims 38 to 43, wherein the first message is a discovery request message or a connection establishment request message.

45. The method of any one of claims 38 to 44, wherein,

46. A communication device comprising a processor and a memory, the memory and the processor being coupled, the processor being configured to perform the method of any one of claims 1-14, or to perform the method of any one of claims 15-24, or to perform the method of any one of claims 25-37, or to perform the method of any one of claims 38-45.

47. A computer readable storage medium for storing a computer program which, when run on a computer, causes the computer to perform the method of any one of claims 1 to 14, or causes the computer to perform the method of any one of claims 15 to 24, or causes the computer to perform the method of any one of claims 25 to 37, or causes the computer to perform the method of any one of claims 38 to 45.

48. A chip system, the chip system comprising:

A processor and an interface from which the processor invokes and executes instructions which when executed by the processor implement the method of any one of claims 1 to 15, or implement the method of any one of claims 15 to 24, or implement the method of any one of claims 25 to 37, or implement the method of any one of claims 38 to 45.

49. A computer program product, characterized in that the computer program product comprises a computer program which, when run on a computer, causes the computer to carry out the method of any one of claims 1 to 15 or causes the computer to carry out the method of any one of claims 15 to 24 or causes the computer to carry out the method of any one of claims 25 to 37 or causes the computer to carry out the method of any one of claims 38 to 45.