CN113747516B

CN113747516B - Method and device for realizing service continuity

Info

Publication number: CN113747516B
Application number: CN202010463560.6A
Authority: CN
Inventors: 张迪; 吴问付; 丁辉
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2020-05-27
Filing date: 2020-05-27
Publication date: 2022-10-11
Anticipated expiration: 2040-05-27
Also published as: CN113747516A; WO2021238882A1

Abstract

A method and device for realizing service continuity, the method includes: when the communication signal of the remote UE is not good, the remote UE switches to access the RAN through the second relay UE, and after the second relay UE receives a communication request message for switching the first service from the remote UE to the second relay UE, the second relay UE sends a first indication to the SMF network element, where the first indication is used to indicate that a session between the SMF2 network element and the UPF2 network element is established or modified and then sends a second indication, so that after the second relay UE receives the second indication from the SMF2 network element, because the second indication is used to indicate that the first service is successfully switched, the second relay UE sends a third indication indicating to release the resource before the remote UE is switched to the remote UE, so that the remote UE releases the resource before the switching.

Description

Method and device for realizing service continuity

Technical Field

The present application relates to the field of communications technologies, and in particular, to a method and an apparatus for implementing service continuity.

Background

To improve wireless spectrum utilization and provide cellular network services to terminals outside of cellular network coverage, cellular communication networks have introduced proximity-based services (ProSe) relay communications. Application scenarios of the method can include scenarios such as enhancement of signals at coverage edge of a base station, relay access to an operator network in a non-coverage area, and the like. The application scenario of enhancing the base station coverage edge signal may be understood as that when a User Equipment (UE) covers an edge area of a base station, due to signal attenuation, signal strength cannot meet a high bandwidth service required by an application service, and therefore, a fifth generation (5 g) communication system may be accessed through a relay UE; the application scenario of relay access to the operator network in the non-coverage area can be understood as that when the UE is out of the coverage area of the operator network, the UE indirectly accesses the 5G network through the relay UE. As shown in fig. 1, when the UE is out of network coverage or the communication signal between the remote UE and the access network device is not good, the UE may assist via the relay UE, that is, the UE communicates with the network-side server via the communication between the UE and the relay UE and the communication between the relay UE and the network-side server.

In the current ProSe relay communication implementation scheme, because the remote UE accessing the relay UE is invisible to the 5G core network side, an Internet Protocol (IP) address of the remote UE is allocated by the relay UE, when the relay UE connected during the UE performs the auxiliary communication through the relay UE is switched, the relay UE newly accessed by the remote UE uses the newly configured IP address to perform communication with the network side server, which causes communication interruption, and thus service continuity is difficult to guarantee.

Disclosure of Invention

The application provides a method and a device for realizing service continuity, which are used for solving the problem of discontinuous communication service caused by switching of relay UE.

In a first aspect, an embodiment of the present application provides a method for implementing service continuity, where the method may be executed by a second relay UE or an internal chip of the second relay UE, and the method is applicable to a scenario where a transmission path of a remote UE is switched and the remote UE accesses a network through the second relay UE after the switching. The method comprises the following steps: after the second relay UE receives a first communication request message for switching a first service from the remote UE to the second relay UE, the second relay UE sends a first indication to a second session management function network element, where the first indication is used to indicate that a session between the second session management function network element and a second user plane function network element is established or modified and then sends a second indication, or the first indication is used to indicate that the first service of the remote UE is switched to the second relay UE, or the first indication is used to indicate that an SSC mode of the first service is a third mode, or the first indication is used to indicate that the first service needs a high-level service continuity, or the first indication is used to indicate that an IP address before switching is released after an IP address after switching is established first. And the second session management function network element sends a second indication to the second relay UE after finishing the session establishment or modification of the first service. And after the second relay UE receives the second instruction from the second session management function network element, because the second instruction is used for indicating that the first service is successfully switched, the second relay UE sends a third instruction for releasing the resource before the switching of the remote UE to the remote UE, so that the remote UE releases the resource before the switching.

In the embodiment of the application, the method can realize that the previous session is disconnected after the service of the remote UE is successfully switched, thereby ensuring the service continuity of the remote UE, and in addition, the resources are released in time after the switching is completed before the switching of the remote UE, so that the resource utilization rate is improved.

In one possible design, after the second relay UE receives the first communication request message, the second relay UE may bind the identification information of the remote UE and the identification information of the first service; after the second relay UE receives the second indication, the second relay UE may further send identifier information of the first service to the remote UE, where the identifier information of the first service is used to indicate that the first service is successfully switched, and after the remote UE receives the third indication and the identifier information of the first service, the remote UE releases resources before switching.

In one possible design, in one case, if an address allocated to the remote UE by a first relay UE connected before the remote UE is switched is in one-to-one correspondence with the remote UE, the remote UE releases the address allocated to the remote UE by the first relay UE; in another case, the third indication may be used to indicate to release the resource of the first service before the handover of the remote UE, that is, if the address allocated by the first relay UE connected before the handover of the remote UE to the first service of the remote UE is in one-to-one correspondence with the remote UE, the remote UE releases the first address allocated by the first relay UE to the first service. The first address in the embodiment of the present application may be at least one of an address and a port number/port range. For example, the first address may be an IPv4 address + port number/port range; or the first address is an IPv6 address.

In one possible design, the second relay UE determines that the SSC pattern of the first service is a third pattern, and sends the first indication to the first session management function network element, otherwise, does not send the first indication, where the third pattern is used for indicating a service continuity requirement that the first service has a high priority.

In one possible design, the second relay UE may determine the SSC pattern for the first service based on at least one of: in a first mode, the second relay UE determines the SSC mode as a third mode according to the relay service identifier of the first service from the remote UE; in a second mode, the second relay UE determines that the SSC mode is a third mode according to the type of the first communication request message from the remote UE as a switching request; in a third mode, the second relay UE determines that the SSC pattern of the first service is the third pattern according to indication information indicating that the SSC pattern is the third pattern in a message from the remote UE.

In a possible design, when the first communication request message is used to indicate that the first service and the second service of the remote UE are switched to the second relay UE, or the second relay UE further receives a second communication request message from the remote UE to indicate that the second service is switched to the second relay UE, the second relay UE sends a first indication to the SMF network element, the first indication is used to indicate that a session between the SMF network element and the UPF network element is established or modified and then sends a second indication and a fourth indication, or the first indication is used to indicate that the first service and the second service of the remote UE are switched to the second relay UE, or the first indication is used to indicate that the SSC mode of the first service and the second service is a third mode, or the first indication is used to indicate that the first service and the second service require a high level of service continuity, or the first indication is used to indicate that the IP address before switching is released after the IP address after switching is established first. And after completing the establishment or modification of the first service and the second service session, the SMF network element sends a second instruction and a fourth instruction to the second relay UE, and when the second relay UE receives the second instruction and the fourth instruction, the second relay UE sends a third instruction for releasing resources before switching to the remote UE.

In one possible design, the second relay UE may send the first indication to the SMF network element when it determines that the SSC pattern for the first service and the SSC pattern for the second service are both in the third mode. And after the second relay UE receives the second indication and the fourth indication from the remote UE, the third indication is sent to the remote UE.

In one possible design, the second relay UE may determine the SSC pattern for the first traffic and the SSC pattern for the second traffic based on at least one of the following. In a first mode, the second relay UE determines that the SSC mode of the first service and the second service is a third mode according to the relay service identification from the remote UE; in a second mode, the second relay UE determines the SSC mode of the first service and the second service as a third mode according to the type of the first communication request message (or the first communication request message and the second communication request message) from the remote UE; in a third mode, the second relay UE determines that the SSC patterns of the first service and the second service are the third pattern according to indication information indicating that the SSC patterns of the first service and the second service are the third pattern in a message from the remote UE.

In a possible design, when receiving the first communication request message, the second relay UE establishes or modifies a protocol data unit, PDU, session for the first service, and in addition, the second relay UE receives a fourth address of the PDU session from the first session management function network element, and also allocates a port number used for transmitting data of the first service on the fourth address to the remote UE, and finally, the second relay UE establishes a correspondence relationship between an identifier of the PDU session, the fourth address, and the port number.

In one possible design, the second relay UE further sends the identification information, the fourth address and the port number of the remote UE to the first session management function network element; or the second relay UE also sends the identification information of the remote UE, the identification information of the PDU session and the port number to the first session management function network element, so that the first session management function network element establishes and stores the binding relationship among the information.

In a second aspect, an embodiment of the present application provides a method for implementing service continuity, where the method may be executed by a remote UE or an internal chip of the remote UE, and the method is applicable to a scenario where a transmission path of the remote UE is switched and the remote UE accesses a network through a second relay UE after the switching. The method comprises the following steps: the remote UE receives identification information of a first service from a second relay UE, wherein the identification information of the first service is used for indicating that the first service is successfully switched; and then, the remote UE determines a first relay UE accessed before the first service of the remote UE is switched to a second relay UE according to the identification information of the first service, then the remote UE sends a fifth instruction for instructing to release the resource before the switching of the remote UE to the first relay UE, and the first relay UE releases the resource before the switching after receiving the fifth instruction.

In the embodiment of the application, the method can release the resources before switching after the service switching of the remote UE is successful, namely, the session connection before switching is disconnected, thereby not only ensuring the service continuity of the remote UE, but also improving the resource utilization rate.

In one possible design, the fifth indication to indicate to release the resources before the handover of the remote UE comprises: the fifth indication is used for indicating to release the first address allocated by the first relay UE to the remote UE, for example, the first address allocated by the first relay UE to the remote UE may be an IPv4 address + port number/port range; or the first address is an IPv6 address. After the first relay UE releases the first address, the remote UE is informed that the first address is released. Alternatively, after the remote UE receives the fifth indication from the first relay UE, the remote UE also synchronously releases the first address.

In a third aspect, an embodiment of the present application provides a method for implementing service continuity, where the method may be executed by a remote UE or an internal chip of the remote UE, and the method is applicable to a scenario where a transmission path of the remote UE is switched and the remote UE accesses a network through a second relay UE after the switching. The method comprises the following steps: and the remote UE receives the identification information of the first service from the second relay UE, wherein the identification information of the first service is used for indicating that the first service is successfully switched, and then the remote UE releases the resources before the remote UE is switched according to the identification information of the first service.

In one possible design, the releasing, by the remote UE, resources before the handover of the remote UE includes: and the remote UE releases the first address allocated to the remote UE by the first relay UE, wherein the first relay UE is the relay UE which is accessed before the first service of the remote UE is switched to the second relay UE. After the remote UE releases the first address, the first relay UE is informed that the first address is released.

In one possible design, the remote UE notifies the first relay UE to delete a first address, a second address and a port number, where the first address is an address allocated by the first relay UE to the remote UE, the second address is an address for transmitting first service data between the first relay UE and the first user plane network element, and the port number is a port number allocated by the first relay UE to a PDU session of the first service.

In a fourth aspect, an embodiment of the present application provides a method for implementing service continuity, where the method may be executed by a first relay UE or an internal chip of the first relay UE, and the method is applicable to a scenario where a transmission path of a remote UE is switched and the remote UE accesses a network through a second relay UE after the switching. The method comprises the following steps: the first relay UE receives a fifth indication from the remote UE, and the first relay UE releases resources before the remote UE is handed over from the first relay UE to the second relay UE according to the fifth indication.

In a possible embodiment, the first relay UE further notifies the second session management function network element and the second user plane function network element to release the resource before the remote UE is handed over. The resource before the handover may include a first address allocated by the first relay UE to the remote UE.

In the embodiment of the application, the method can realize that the first relay UE releases the resources before switching after the service switching of the remote UE is successful, namely, the session connection before switching is disconnected, thereby not only ensuring the service continuity of the remote UE, but also improving the resource utilization rate.

In a fifth aspect, an embodiment of the present application provides a method for implementing service continuity, where the method may be executed by a second session management function network element or an internal chip of the second session management function network element, and the method is applicable to a scenario where a transmission path of a remote UE is switched and the remote UE accesses a network through a second relay UE after the switching. The method comprises the following steps: and the second session management function network element sends a second indication for indicating the successful switching of the first service to the second relay UE after the session of the interface between the second session management function network element and the second user plane function network element is established or modified according to the first indication, so that the second relay UE indicates the remote UE to release resources before switching.

In the embodiment of the application, when the relay UE connected with the remote UE is switched, the second session management function network element indicates to disconnect the previous session after the service of the remote UE is successfully switched, so that the service continuity of the remote UE is ensured.

In one possible design, a second session management function network element allocates a fourth address to a PDU session established or self-modified for a first service, receives identification information and a port number of a remote UE from a second relay UE, and binds the identification information of the first service, the fourth address, the identification information of the remote UE, and the port number; or, the second session management function network element receives the identification information of the remote UE, the identification information of the DU session, and the port number from the second relay UE, and binds the identification information of the first service, the fourth address, the identification information of the remote UE, the identification information of the PDU session, and the port number.

In a sixth aspect, an embodiment of the present application provides a method for implementing service continuity, where the method may be executed by a unified data management function network element or an internal chip of the unified data management network element, or the method may be executed by a unified data storage network element or an internal chip of the unified data storage. The method is suitable for a scene that the transmission path of the remote UE is switched and the switched remote UE is accessed to the network through the second relay UE. The method comprises the following steps: the unified data management network element or the unified data storage determines that a session management function network element serving a first service of the remote UE is switched from the first session management function network element to a second session management function network element; and the unified data management network element or the unified data storage sends a first notice to the first session management function network element, wherein the first notice is used for informing the first session management function network element that the first service is no longer provided for the remote UE.

In the embodiment of the present application, the release process of the resources before the handover is triggered by the network element with the data management function or the unified data storage on the network side, although the remote UE accesses the relay UE to perform the handover, the resources before the handover are still released after the session is established or modified, and the transmission of the service with high priority service continuity is not interrupted, that is, the service transmission between the remote UE and the network server is not interrupted before and after the transmission path is switched, thereby ensuring the service continuity.

In one possible design, before the handover, the unified data management network element or the unified data storage receives the related information of the first service before the handover from the first session management function network element; and after switching, the unified data management network element or the unified data storage receives the relevant information of the switched first service from the second session management function network element. The unified data management network element or the unified data storage may bind the related information of the first service before the handover and the identification information of the first session management function network element; the unified data management network element or the unified data storage may bind the information related to the switched first service and the identifier information of the second session management function network element. When the unified data management network element or the unified data storage determines that the session management function network elements are different according to the identification information of the first session management function network element corresponding to the relevant information of the first service and the identification information of the second session management function network element corresponding to the relevant information of the first service, determining that the session management function network element of the first service serving the remote UE is switched from the first session management function network element to the second session management function network element; or, when the unified data management network element or the unified data storage determines that the relay UEs are different according to the identification information of the first relay UE corresponding to the relevant information of the first service and the identification information of the second relay UE corresponding to the relevant information of the first service, determining that the session management function network element serving the first service of the remote UE is switched from the first session management function network element to the second session management function network element.

In one possible design, the information related to the first service before handover includes identification information of the remote UE. In addition, further, the information related to the first service before handover further includes any one or more of the following items: the method comprises the steps of switching the data of the first service before switching by using a port number, the PDU session identification of the first service before switching and the IP address of the first service before switching.

In one possible design, the information related to the first service after handover includes identification information of the remote UE. In addition, further, the information related to the first service after the handover further includes and any one or more of the following: the port number of the data of the switched first service, the PDU session identification of the switched first service and the IP address of the switched first service.

In a seventh aspect, an embodiment of the present application provides a method for implementing service continuity, where the method may be executed by a first session management function network element or an internal chip of the first session management function network element, and the method is applicable to a scenario where a transmission path of a remote UE is switched and the remote UE accesses a network through a second relay UE after the switching. The method comprises the following steps: a first session management function network element receives a first notification from a unified data management network element, wherein the first notification is used for notifying the first session management function network element that the remote UE is no longer provided with the service of the first service; therefore, the first session management function network element notifies the first user plane function network element and the first relay UE to release the resource before the remote UE is switched from the first relay UE to the second relay UE.

In the embodiment of the present application, the resource release process before switching is triggered by the network element of the data management function on the network side, and although the remote UE is switched when accessing the relay UE, the resource before switching is still released after session establishment or modification, and the transmission of the service with high priority service continuity is not interrupted, that is, the service transmission between the remote UE and the network server is not interrupted before and after the transmission path is switched, thereby ensuring the service continuity.

In one possible design, the notifying, by the first session management function network element, the user plane function network element and the first relay UE to release resources of the remote UE before the remote UE is handed over from the first relay UE to the second relay UE includes:

the first session management function network element informs the first user plane function network element to release the port number information allocated to the first service of the first relay UE; the port number information is used for indicating the first user plane function network element to release the downlink data stream received by the port number indicated by the port number information;

and the first session management function network element informs the first relay UE to release a first address, wherein the first address is an address allocated to the remote UE by the first relay UE.

In an eighth aspect, an embodiment of the present application provides a method for implementing service continuity, where the method may be executed by a first relay UE or an internal chip of the first relay UE, and the method is applicable to a scenario where a transmission path of a remote UE is switched and the remote UE accesses a network through a second relay UE after the switching. The method comprises the following steps: the first relay UE receives a second notice from the first session management function network element; and the first relay UE releases the resources before the remote UE is switched from the first relay UE to the second relay UE according to the second notice.

In one possible embodiment, the resource includes a first address, and the first address is an address allocated by the first relay UE to the remote UE.

In a ninth aspect, the present application provides a communication apparatus, which may be a second relay UE or a chip disposed inside the second relay UE. The communication apparatus has a function implemented by the second relay UE or a chip disposed inside the second relay UE, for example, the communication apparatus includes a module, a unit, or a means (means) corresponding to the step of the first aspect, and the function, the unit, or the means may be implemented by software, or implemented by hardware executing corresponding software.

In one possible design, the communication device includes a processing unit, a communication unit, where the communication unit may be configured to send and receive signals to and from other devices to implement communication between the communication device and the other devices, for example, the communication unit is configured to receive a first communication request message from a remote UE; the processing unit may be adapted to perform some internal operations of the communication device. The functions performed by the processing unit, the communication unit may correspond to the steps involved in the second relay UE in the aspects described above.

In one possible design, the communication device includes a processor, and may further include a transceiver for transceiving signals, the processor executing program instructions to perform the method in any possible design or implementation of the above aspects. Wherein the communications apparatus can further include one or more memories for coupling with the processor. The one or more memories may be integrated with the processor or separate from the processor, which is not limited in this application. The memory may hold the necessary computer programs or instructions to implement the functions involved in the aspects described above. The processor may execute computer programs or instructions stored by the memory that, when executed, cause the communications apparatus to implement the method in any possible design or implementation referred to by the second relay UE in the aspects above.

In one possible design, the communication device includes a processor and a memory, and the memory can store the necessary computer programs or instructions for implementing the functions of the first aspect described above. The processor may execute computer programs or instructions stored by the memory that, when executed, cause the communications apparatus to implement the method in any possible design or implementation referred to by the second relay UE in the aspects above.

In one possible design, the communications apparatus includes at least one processor and interface circuitry, where the at least one processor is configured to communicate with other apparatuses via the interface circuitry and to perform the method performed by the second relay UE in any of the possible designs or implementations of the aspects.

In a tenth aspect, the present application provides a communication apparatus, which may be a remote UE or a chip disposed inside the remote UE. The communication apparatus has a function implemented by the remote UE or a chip disposed inside the remote UE, for example, the communication apparatus includes a module or a unit or a means (means) corresponding to the step of performing the second aspect or the third aspect, and the function or the unit or the means may be implemented by software or hardware, or may be implemented by hardware and corresponding software.

In one possible design, the communication device includes a processing unit, a communication unit, where the communication unit may be configured to transceive signals to enable communication between the communication device and other devices, e.g., the communication unit is configured to receive a third indication from the second relay UE; the processing unit may be adapted to perform some internal operations of the communication device. The functions performed by the processing unit, the communication unit may correspond to the steps involved in the remote UE in the aspects described above.

In one possible design, the communication device includes a processor, and may further include a transceiver for transceiving signals, the processor executing program instructions to implement the method in any possible design or implementation of the above aspects. Wherein the communications apparatus can further include one or more memories for coupling with the processor. The one or more memories may be integrated with the processor or separate from the processor, which is not limited in this application. The memory may hold the necessary computer programs or instructions to implement the functions involved in the aspects described above. The processor may execute computer programs or instructions stored by the memory that, when executed, cause the communications apparatus to implement the method in any possible design or implementation referred to by the remote UE in the aspects described above.

In one possible design, the communication device comprises a processor and a memory, which may hold the necessary computer programs or instructions to implement the functionality referred to in the first aspect above. The processor may execute computer programs or instructions stored by the memory that, when executed, cause the communications apparatus to implement the method in any possible design or implementation referred to by the remote UE in the aspects described above.

In one possible design, the communications apparatus includes at least one processor and interface circuitry, where the at least one processor is configured to communicate with other apparatuses via the interface circuitry and to perform the method performed by the remote UE in any of the possible designs or implementations of the above aspects.

In an eleventh aspect, the present application provides a communication apparatus, which may be a first relay UE or a chip disposed inside the first relay UE. The communication apparatus has a function implemented by the first relay UE or a chip disposed inside the first relay UE, for example, the communication apparatus includes a module or a unit or means (means) corresponding to the step of performing the fourth aspect or the eighth aspect, and the function or the unit or the means may be implemented by software, or implemented by hardware executing corresponding software.

In one possible design, the communication device includes a processing unit, a communication unit, where the communication unit may be configured to send and receive signals to implement communication between the communication device and other devices, for example, the communication unit is configured to receive the second notification from the first session management function network element; the processing unit may be adapted to perform some internal operations of the communication device. The functions performed by the processing unit, the communication unit may correspond to the steps involved in the first relay UE in the aspects described above.

In one possible design, the communication device includes a processor, and may further include a transceiver for transceiving signals, the processor executing program instructions to perform the method in any possible design or implementation of the above aspects. Wherein the communications apparatus can further include one or more memories for coupling with the processor. The one or more memories may be integrated with the processor or separate from the processor, which is not limited in this application. The memory may hold the necessary computer programs or instructions to implement the functions involved in the aspects described above. The processor may execute a computer program or instructions stored by the memory that, when executed, cause the communications apparatus to implement the method in any possible design or implementation related to the first relay UE of the above aspects.

In one possible design, the communication device comprises a processor and a memory, which may hold the necessary computer programs or instructions to implement the functionality referred to in the first aspect above. The processor may execute computer programs or instructions stored by the memory that, when executed, cause the communications apparatus to implement the method in any possible design or implementation referred to by the first relay UE in the aspects above.

In one possible design, the communications apparatus includes at least one processor and interface circuitry, where the at least one processor is configured to communicate with other apparatuses via the interface circuitry and to perform the method performed by the first relay UE in any of the possible designs or implementations of the aspects.

In a twelfth aspect, the present application provides a communication apparatus, where the communication apparatus may be a second session management function network element or a chip disposed inside the second session management function network element. The communication apparatus has a function implemented by the second session management function network element or a chip disposed inside the second session management function network element, for example, the communication apparatus includes a module or a unit or means (means) corresponding to the step of executing the fifth aspect, and the function or the unit or the means may be implemented by software or hardware, or may be implemented by hardware executing corresponding software.

In one possible design, the communication device includes a processing unit, a communication unit, where the communication unit may be configured to transceive signals to enable communication between the communication device and other devices, e.g., the communication unit is configured to receive a first indication from a second relay UE; the processing unit may be adapted to perform some internal operations of the communication device. The functions performed by the processing unit and the communication unit may correspond to the steps involved in the second session management function network element in the aspects described above.

In one possible design, the communication device includes a processor, and may further include a transceiver for transceiving signals, the processor executing program instructions to perform the method in any possible design or implementation of the above aspects. Wherein the communications apparatus can further comprise one or more memories for coupling with the processor. The one or more memories may be integrated with the processor or separate from the processor, which is not limited in this application. The memory may hold the necessary computer programs or instructions to implement the functions involved in the aspects described above. The processor may execute a computer program or instructions stored by the memory which, when executed, causes the communication device to implement the method of any possible design or implementation referred to in the second session management function network element of the above aspects.

In one possible design, the communication device includes a processor and a memory, and the memory can store the necessary computer programs or instructions for implementing the functions of the first aspect described above. The processor may execute a computer program or instructions stored by the memory which, when executed, causes the communication device to implement the method of any possible design or implementation referred to by the second session management function network element of the above aspects.

In one possible design, the communication device includes at least one processor and an interface circuit, where the at least one processor is configured to communicate with other devices through the interface circuit and to perform the method performed by the second session management function network element in any possible design or implementation of the above aspects.

In a thirteenth aspect, the present application provides a communication device, where the communication device may be a unified data management network element or a chip disposed inside the unified data management network element. The communication device has a function implemented by the unified data management network element or a chip disposed inside the unified data management network element, for example, the communication device includes a module or a unit or a means (means) corresponding to the step of executing the sixth aspect, and the function or the unit or the means may be implemented by software, or implemented by hardware executing corresponding software.

In one possible design, the communication device includes a processing unit, a communication unit, wherein the communication unit may be configured to send and receive signals to and from the communication device to implement communication between the communication device and other devices, for example, the communication unit is configured to send a first notification to a first session management function network element; the processing unit may be adapted to perform some internal operations of the communication device. The functions performed by the processing unit and the communication unit may correspond to the steps involved in the above aspects of the unified data management network element.

In one possible design, the communication device includes a processor, and may further include a transceiver for transceiving signals, the processor executing program instructions to perform the method in any possible design or implementation of the above aspects. Wherein the communications apparatus can further include one or more memories for coupling with the processor. The one or more memories may be integrated with the processor or separate from the processor, which is not limited in this application. The memory may hold the necessary computer programs or instructions to implement the functions involved in the aspects described above. The processor may execute computer programs or instructions stored by the memory that, when executed, cause the communication device to implement the method in any possible design or implementation referred to by the above aspects of the unified data management network element.

In one possible design, the communication device comprises a processor and a memory, which may hold the necessary computer programs or instructions to implement the functionality referred to in the first aspect above. The processor may execute computer programs or instructions stored by the memory that, when executed, cause the communication device to implement the method in any possible design or implementation referred to by the above aspects of the unified data management network element.

In one possible design, the communication device includes at least one processor and an interface circuit, where the at least one processor is configured to communicate with other devices through the interface circuit and to perform the method performed by the unified data management network element in any of the possible designs or implementations of the above aspects.

In a fourteenth aspect, the present application provides a communication apparatus, where the communication apparatus may be a first session management function network element or a chip disposed inside the first session management function network element. The communication apparatus has a function implemented by the first session management functional network element or a chip disposed inside the first session management functional network element, for example, the communication apparatus includes a module or a unit or means (means) corresponding to the step of executing the fifth aspect, and the function or the unit or the means may be implemented by software, or implemented by hardware executing corresponding software.

In one possible design, the communication device includes a processing unit, a communication unit, where the communication unit may be configured to transceive signals to enable communication between the communication device and other devices, e.g., the communication unit is configured to receive a first indication from a second relay UE; the processing unit may be adapted to perform some internal operations of the communication device. The functions performed by the processing unit and the communication unit may correspond to the steps involved in the first session management function network element in the aspects described above.

In one possible design, the communication device includes a processor, and may further include a transceiver for transceiving signals, the processor executing program instructions to perform the method in any possible design or implementation of the above aspects. Wherein the communications apparatus can further include one or more memories for coupling with the processor. The one or more memories may be integrated with the processor or separate from the processor, which is not limited in this application. The memory may hold the necessary computer programs or instructions to implement the functions involved in the aspects described above. The processor may execute a computer program or instructions stored by the memory which, when executed, cause the communication device to implement the method in any possible design or implementation referred to by the first session management function network element of the above aspects.

In one possible design, the communication device includes a processor and a memory, and the memory can store the necessary computer programs or instructions for implementing the functions of the first aspect described above. The processor may execute a computer program or instructions stored by the memory which, when executed, cause the communication device to implement the method in any possible design or implementation referred to by the first session management functionality network element of the above aspects.

In one possible design, the communication device includes at least one processor and an interface circuit, where the at least one processor is configured to communicate with other devices through the interface circuit and to perform the method performed by the first session management function network element in any of the possible designs or implementations of the above aspects.

In a fifteenth aspect, an embodiment of the present application provides a communication system, where the communication system includes a second relay UE, a remote UE, a first relay UE, and a second session management function network element, where the first relay UE and the second relay UE are configured to perform session management;

the second relay UE may be configured to perform the first aspect or any of the methods of the first aspect.

The remote UE may be configured to perform any of the methods of the second aspect or the second aspect, or any of the methods of the third aspect or the third aspect.

The first relay UE may be configured to perform any one of the methods of the fourth aspect or the fourth aspect.

The second session management function network element may be configured to perform any one of the methods of the fifth aspect or the fifth aspect.

In a sixteenth aspect, an embodiment of the present application provides a communication system, where the communication system includes a data management function network element and a first session management function network element, where;

the data management function network element may be configured to perform any one of the methods of the sixth aspect or the sixth aspect.

The first session management function network element may be configured to perform any one of the methods of the seventh aspect or the seventh aspect.

In a seventeenth aspect, the present application provides a computer-readable storage medium having computer-readable instructions stored thereon which, when read and executed by a computer, cause the computer to perform the method of any one of the possible designs of the above aspects.

In an eighteenth aspect, the present application provides a computer program product which, when read and executed by a computer, causes the computer to perform the method of any one of the possible designs of the various aspects described above.

In a nineteenth aspect, the present application provides a chip comprising a processor coupled with a memory for reading and executing a software program stored in the memory to implement the method in any one of the possible designs of the above aspects.

Drawings

Fig. 1 is a schematic diagram of a communication scenario provided in the prior art;

fig. 2 is a schematic architecture diagram of a communication system according to an embodiment of the present application;

fig. 3A to fig. 3B are schematic diagrams of two application communication scenarios provided in the embodiment of the present application;

fig. 4 is a schematic flowchart of a first method for implementing service continuity according to an embodiment of the present application;

fig. 5 is a schematic flowchart of a second method for implementing service continuity according to an embodiment of the present application;

fig. 6 is a schematic flowchart of a PDU session establishment method before handover according to an embodiment of the present application;

fig. 7A is a schematic diagram of a handover method according to an embodiment of the present application;

fig. 7B is a schematic diagram of a switching scenario provided in the embodiment of the present application;

fig. 8 is a schematic view of a switching scenario provided in an embodiment of the present application;

fig. 9 is a flowchart illustrating another PDU session establishment method before handover according to an embodiment of the present application;

fig. 10 is a schematic diagram of another handover method according to an embodiment of the present application;

FIG. 11 is a possible exemplary block diagram of the devices involved in the embodiments of the present application;

fig. 12 is a schematic structural diagram of a remote UE or a second relay UE according to an embodiment of the present application;

fig. 13 is a schematic structural diagram of a network device 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 clearer, the embodiments of the present application will be described in further detail with reference to the accompanying drawings.

Hereinafter, some terms in the embodiments of the present application are explained to facilitate understanding by those skilled in the art.

1) A terminal equipment (terminal equipment), also known as a terminal, user Equipment (UE), mobile Station (MS), mobile Terminal (MT), etc., is a device that provides voice and/or data connectivity to a user and may include, for example, a handheld device with wireless connection capability or a processing device connected to a wireless modem.

The terminal may communicate with a core network via a Radio Access Network (RAN), exchanging voice and/or data with the RAN. The terminal may include a User Equipment (UE), a wireless terminal, a mobile terminal, a subscriber unit (subscriber unit), a subscriber station (subscriber station), a mobile station (mobile station), a remote station (remote station), an Access Point (AP), a remote terminal (remote terminal), an access terminal (access terminal), a user terminal (user terminal), a user agent (user agent), a user equipment (user device), or the like. In the embodiment of the present application, a remote UE (remote UE) may connect to a network through an access network device, or may connect to the network through a relay UE.

For example, mobile phones (or so-called "cellular" phones), computers with mobile terminals, portable, pocket, hand-held, computer-included or vehicle-mounted mobile devices, smart wearable devices, and the like may be included. For example, personal Communication Service (PCS) phones, cordless phones, session Initiation Protocol (SIP) phones, wireless Local Loop (WLL) stations, personal Digital Assistants (PDAs), and the like.

Alternatively, the terminal device may also include a limited device, such as a device with lower power consumption, or a device with limited storage capability, or a device with limited computing capability, etc. Examples of information sensing devices include bar codes, radio Frequency Identification (RFID), sensors, global Positioning Systems (GPS), laser scanners, and the like.

By way of example and not limitation, in the embodiments of the present application, the smart wearable device is a generic term for intelligently designing daily wearing by applying wearable technology, and developing wearable devices, such as glasses, gloves, watches, clothes, shoes, and the like. The smart wearable device is a portable device that is worn directly on the body or integrated into the clothing or accessories of the user.

The intelligent wearable device is not only a hardware device, but also realizes powerful functions through software support, data interaction and cloud interaction. Generalized intelligent wearable device includes that the function is full, size is big, can not rely on the smart mobile phone to realize complete or partial function, for example: smart watches or smart glasses and the like, and only focus on a certain type of application functions, and need to be used in cooperation with other devices such as smart phones, such as various smart bracelets, smart helmets, smart jewelry and the like for monitoring physical signs.

Alternatively, the terminal may be a Virtual Reality (VR) device, an Augmented Reality (AR) device, a wireless terminal in industrial control (industrial control), a wireless terminal in unmanned driving (drive), a wireless terminal in remote medical supply (remote), a wireless terminal in smart grid (smart grid), a wireless terminal in transportation safety (transportation safety), a wireless terminal in smart city (smart city), a wireless terminal in smart home (smart home), or the like.

2) A (radio) access network (R) AN apparatus, e.g., including a base station (e.g., AN access point), may refer to AN apparatus in AN access network that communicates over the air with wireless terminals via one or more cells. The (radio) access network device may be configured to interconvert received air frames and Internet Protocol (IP) packets as a router between the remote UE and the rest of the access network, which may include an IP network. The (radio) access network device may also coordinate attribute management for the air interface.

For example, the (wireless) access network device may include a Radio Network Controller (RNC), a Node B (NB), a Base Station Controller (BSC), a Base Transceiver Station (BTS), a home base station (e.g., home evolved NodeB, or home Node B, HNB), a Base Band Unit (BBU), or a wireless fidelity (Wi-Fi) Access Point (AP), etc.

The (radio) access network equipment may also comprise an evolved base station (NodeB or eNB or e-NodeB, electronic Node B) in a Long Term Evolution (LTE) system or an evolved LTE system (LTE-Advanced, LTE-a) or a fourth generation mobile communication technology (4 g) system.

Alternatively, the (wireless) access network device may also include a next generation node B (gNB), a Transmission and Reception Point (TRP), or a Transmission Point (TP) in a 5G system or a New Radio (NR) system.

Alternatively, the (wireless) access network device may also include a Centralized Unit (CU) and/or a Distributed Unit (DU) in a cloud access network (cloudlan) system, which is not limited in the embodiment of the present application. In the embodiments of the present application, the technical terms "(radio) access network device" and "access network device" may be used interchangeably.

3) The Core Network (CN) device is connected to a plurality of access networks, and includes a Circuit Switched (CS) domain and/or a Packet Switched (PS) domain, where the CS network element includes a mobile switching center, an access location register and a gateway mobile switching center, and the PS network element includes a General Packet Radio Service (GPRS) node and a gateway GPRS support node. Some network elements such as home location register, visitor location register, and authentication center can be shared by CS domain and PS domain.

4) The "plurality" in the embodiments of the present application means two or more, and in view of this, the "plurality" in the embodiments of the present application may also be understood as "at least two". "at least one" is to be understood as meaning one or more, for example one, two or more.

For example, including at least one means including one, two, or more, and does not limit which ones are included, e.g., including at least one of A, B and C, then included may be A, B, C, A and B, A and C, B and C, or a and B and C.

"and/or" describes the association relationship of the associated objects, meaning that there may be three relationships, e.g., a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone.

In addition, the character "/" generally indicates that the preceding and following related objects are in an "or" relationship, unless otherwise specified. The terms "system" and "network" in the embodiments of the present application may be used interchangeably.

Unless stated to the contrary, the embodiments of the present application refer to the ordinal numbers "first", "second", etc., for distinguishing between a plurality of objects, and do not limit the sequence, timing, priority, or importance of the plurality of objects.

Having described some of the concepts related to the embodiments of the present application, the following describes features of the embodiments of the present application.

In view of this, an embodiment of the present application provides a method for implementing service continuity, in which after a second relay UE receives a first communication request message from a remote UE, the second relay UE determines that a first service of the remote UE is switched to the second relay UE, so that the second relay UE sends a first instruction to a second session management function network element, the first instruction is used to instruct a session between the second session management function network element and a second user plane function network element to be established or modified, and then sends a second instruction, because the second instruction is used to instruct the first service to be successfully switched, when the second relay UE receives the second instruction from the second session management function network element, the second relay UE sends a third instruction to the remote UE, and the remote UE releases resources before switching after receiving the third instruction.

The method and the device are based on the same inventive concept, and because the principles of solving the problems of the method and the device are similar, the implementation of the device and the method can be mutually referred, and repeated parts are not repeated. In the description of the embodiment of the present application, "and/or" describes an association relationship of associated objects, which means that three relationships may exist, for example, a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship. At least one referred to in this application means one or more; plural means two or more. In addition, it should be understood that, in this embodiment, both the core network device and the access network device may be referred to as a network device. In the description of the present application, for convenience of explanation, embodiments of the present application may be described using terms such as "first," "second," and the like, it being understood that such terms are not to be construed as indicating or implying relative importance, nor order.

The technical scheme of the embodiment of the application can be applied to various communication systems, for example: long Term Evolution (LTE) system, worldwide Interoperability for Microwave Access (WiMAX) communication system, fifth generation (5 th generation, 5G) communication system, such as new radio access technology (NR), and future communication systems, such as 6G system. Specifically, for example, the method may be applied to a communication scenario of Machine Type Communication (MTC), a communication scenario of narrowband internet of things (NB-IoT) based on cellular, and a transmission scenario of any downlink small data packet.

The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

Fig. 2 is a schematic architecture diagram of a possible communication system applicable to the embodiment of the present application. The communication system architecture of the system shown in fig. 2 is also divided into two parts, a radio access network and a core network. The radio access network is a next generation radio access network (NG-RAN) for implementing radio access related functions. The core network includes: an access and mobility management function (AMF) network element, a Session Management Function (SMF) network element, a User Plane Function (UPF) network element, a Unified Data Management (UDM) network element, and the like. The AMF network element is mainly responsible for mobility management. The AMF network element may also be referred to as an AMF device or an AMF entity. The SMF network element is mainly responsible for session management. An SMF network element may also be referred to as an SMF device or an SMF entity. The UPF network element is mainly responsible for processing, such as forwarding and the like, the user packet. The UE may access the DN by establishing a session from the UE to the NG-RAN to the UPF to a Data Network (DN). The UDM network element is mainly used for storing subscription information of the remote UE.

It should be understood that the communication system architecture provided in the embodiment of the present application is only an example, and may be applied to a 5G system, an advanced long term evolution (LTE-a) system, a Worldwide Interoperability for Microwave Access (WiMAX), a Wireless Local Area Network (WLAN) system, or the like.

In addition, the communication system architecture may also be applied to future-oriented communication technologies, and the communication system architecture described in the embodiment of the present application is for more clearly illustrating the technical solution of the embodiment of the present application, and does not form a limitation on the technical solution provided in the embodiment of the present application.

For convenience of illustration, the method is applied to the communication system architecture shown in fig. 2 as an example. In the following description, the interactive devices may include a remote UE, a relay UE, a RAN, an SMF, a UPF, a UDM, and the like.

The embodiment of the present application provides a method for implementing service continuity, where the method may be applied to a scenario in which a remote UE switches from a direct access RAN1 to a scenario in which the remote UE accesses a RAN2 through a second relay UE, as shown in fig. 3A, in the scenario, when a communication signal between the remote UE and the RAN1 is not good, the remote UE switches from the direct access RAN1 to the access RAN2 through the second relay UE. Thus, after the transmission path is switched, the remote UE can transmit uplink and downlink data with the network server through the transmission path between the second relay UE and the UPF 2.

Or, the method provided by the embodiment of the present application may be applied to a scenario in which the remote UE switches from accessing the first relay UE to accessing the second relay UE. As shown in fig. 3B, in this scenario, when the location of the remote UE moves or the communication signal between the remote UE and the first relay UE is not good, the remote UE switches from being connected to the first relay UE to being connected to the second relay UE. Thus, after the transmission path is switched, the remote UE can transmit uplink and downlink data with the network server through the transmission path between the second relay UE and the UPF 2.

It should be noted that, in the scenarios shown in fig. 3A and fig. 3B, RAN1 and RAN2 may be the same RAN or different RANs, UPF1 and UPF2 may be the same RAN or different RANs, and SMF1 and SMF2 may be different SMFs or the same SMF.

The technical scheme provided by the embodiment of the application is described below with reference to the accompanying drawings.

Example one

Referring to fig. 4, a schematic flowchart of a first method for implementing service continuity provided in the embodiment of the present application is shown, where the method includes the following steps.

Step 401, the second relay UE receives a first communication request message from the remote UE. The first communication request message is used for indicating that the first service of the remote UE is switched to the second relay UE.

It should be noted that before the remote UE sends the first communication request message to the second relay UE, the remote UE may directly access the RAN in the manner shown in fig. 3A before handover; alternatively, the remote UE may access the RAN through the first relay UE in the manner shown in fig. 3B before the handover.

When the remote UE is out of network coverage or a communication signal between the remote UE and the RAN is not good, and after the remote UE and the second relay UE find each other, the remote UE sends a first communication request message to the second relay UE, where the first communication request message may be a handover request message directly instructing the first service to be handed over to the second relay UE, or an indirect communication request message indirectly instructing the first service to be handed over to the second relay UE, and specifically, refer to any one of the following cases:

in case a, the first communication request message is a handover communication request message, and the handover request message itself directly indicates that the first service of the remote UE is handed over to the second relay UE.

In case b, the first communication request message is an indirect communication request message. The indirect communication request message indirectly indicates that the first service of the remote UE is switched to the second relay UE.

Specifically, the indirect communication request message is a request message sent by the remote UE to the second relay UE, where the request message is used by the remote UE to request communication with the second relay UE, and the indirect communication request message carries a handover request indication, and the handover request indicates that the first service of the remote UE is handed over to the second relay UE.

Specifically, the handover request indication may be an identifier of the remote UE and an identifier of the first service, where the identifier of the remote UE and the identifier of the first service may be used to indicate that the first service of the remote UE is handed over to the second relay UE, that is, a transmission path of the remote UE is handed over.

Illustratively, after discovering the second relay UE, the remote UE establishes a PC5 communication link with the second relay UE, and notifies the second relay UE of switching the first service of the remote UE to the second relay UE through the PC5 communication link. For example, the remote UE sends a relay access request through the PC5 communication link, where the relay access request message is used to instruct the remote UE to switch the first service to the second relay UE. For example, referring to fig. 3B, after discovering the second relay UE, the remote UE sends a relay access request message to the second relay UE, where the message at least includes an identifier of the remote UE (e.g., a remote UE ID) and an identifier of the first service. The identifier of the remote UE and the identifier of the first service may be used to instruct the remote UE to switch the first service to the second relay UE, that is, the transmission path of the remote UE is switched.

In this embodiment, in a possible embodiment, after the second relay UE receives the first communication request message, the second relay UE requests the second Session management function network element to establish or modify a PDU Session for the remote UE, and after the second Session management function network element establishes or modifies the PDU Session, the second relay UE allocates identification information of the PDU Session (PDU Session ID) and a fourth address of the PDU Session (the fourth address is referred to by ip @2 #) for the PDU Session. That is, after the PC5 secure link between the remote UE and the second relay UE is successfully established, the remote UE initiates a Dynamic Host Configuration Protocol (DHCP) process, and the second relay UE configures a third address for the remote UE or a service of the remote UE (the third address is referred to as ip @1 #) in this document. The third address is used for communication between the remote UE and the second relay UE. Meanwhile, the second relay UE allocates a port number/port range (port number) to the remote UE, where the port number/port range communicates with the PDU session anchor point or DN at the fourth address.

Specifically, the second relay UE may configure the third address in any one of the following two manners, and establish the binding relationship in any one of the following two manners.

In the first method, the second relay UE allocates the third address to the remote UEs, where the third address is allocated in granularity of the remote UEs, and each remote UE uniquely corresponds to one third address. If the UE includes at least one service, where the at least one service includes the first service, each service has identification information of a PDU session uniquely corresponding to the service, a fourth address of the PDU session on the network side, a port number/port range, and an SSC pattern, for example, a binding relationship established by the second relay UE is as shown in table 1.

TABLE 1

In the second mode, the second relay UE allocates the third address to the remote UE by using the service as granularity, and the second relay UE allocates a unique corresponding third address to each service of each remote UE. If the UE includes at least one service, wherein the at least one service includes the first service, each service has the identification information of the PDU session, the fourth address, the port number/port range, and the SSC mode, for example, the binding relationship established by the second relay UE is shown in table 2.

TABLE 2

In a possible embodiment, the second relay UE establishes a binding relationship among the identification information of the remote UE, the fourth address, and the port number/port range, and reports the binding relationship to the second session management function network element; or the second relay UE establishes the mapping relation among the identification information of the remote UE, the identification information of the PDU session and the port number/port range, and reports the binding relation to the second session management function network element. Specifically, the second relay UE may report according to the number of PDU sessions served by the remote UE, for example, a binding relationship reported each time corresponds to one PDU session; or, the second relay UE may report all the binding relationships corresponding to the PDU sessions served by the remote UE to the second session management function network element through one report. The specific process that the second relay UE reports the binding relationship to the second session management function network element is divided into two steps, in the first step, the AMF network element receives report information (remote UE report) from the remote UE, and if the report information contains identification information (PDU session ID) of a plurality of PDU sessions; then, when the AMF network element determines that the PDU session identification information corresponds to the same second session management function network element, the AMF network element forwards the report information to the second session management function network element.

Step 402, the second relay UE sends a first indication to the second session management function network element. The first indication is used for indicating the session establishment or modification of an interface between the second session management function network element and the second user plane function network element and then sending a second indication.

In this embodiment, the first indication may be a handover request indication 2 (path switch indication). Exemplarily, referring to fig. 3B, after discovering the second relay UE, the remote UE sends a relay access request message to the second relay UE, where the relay access request message is the first communication request message, and after receiving the relay access request message, the second relay UE sends a session establishment message or a PDU session modification request message to the SMF2 network element, and the message carries the identifier of the first service, the identifier of the remote UE, and the first indication, so that the SMF2 network element determines that the first service of the remote UE is switched to the second relay UE according to the first indication and then sends the second indication.

When the second relay UE determines that the SSC mode of the first service is the third mode, sending a first indication to the first session management function network element, specifically, triggering the second relay UE to send the first indication to the second session management function network element may refer to any one of the following cases:

in case a, when the Session and Service Continuity (SSC) mode of the first service carried in the message received by the second relay UE from the remote UE is the third mode, that is, the value of the SSC mode of the first service is 3, because the third mode is used to represent that the first service requires high-priority service continuity, the remote UE is allowed to establish a session anchor point reaching the same DN before switching, and therefore the second relay UE sends the first indication to the second session management function network element.

In case B, the second relay UE determines that the SSC mode of the first service is the third mode according to a relay service identifier (relay service code) of the first service from the remote UE, so that the second relay UE sends the first indication to the second session management function network element.

In case C, the second relay UE determines that the SSC mode is the third mode according to the type of the first communication request message being a handover request, in other words, when the first communication request message is a handover request (handover request) message, the second relay UE determines that the SSC mode of the first service is the third mode.

In step 403, the second session management function network element establishes or modifies a session of an interface between the second session management function network element and the second user plane function network element.

Specifically, since the second session management function network element obtains the binding relationship between the identification information of the remote UE, the address of the PDU session, and the port number/port range, or the binding relationship between the identification information of the remote UE, the identification information of the PDU session, and the port number/port range from the second relay UE, the second session management function network element determines to find one or more corresponding user plane function network elements according to the correspondence between the address of the PDU session or the identification information of the PDU session and the identification of the N4 session, and initiates an N4 session modification procedure to the second user plane function network element, so as to establish or modify a session of an interface between the second session management function network element and the second user plane function network element, and place the port number or the port range in a Packet Detection Rule (PDR).

It should be noted that, when the second session management network element determines, according to the identifier of the first service, that there is no PDU session corresponding to the first service, the second session management functional network element newly establishes a session of an interface between the second session management functional network element and the second user plane functional network element; and when the second session management network element determines that the PDU session corresponding to the first service exists according to the identifier of the first service, the second session management functional network element modifies the PDU session corresponding to the first service.

In other words, in conjunction with step 402 above, step 403 may also include any one or more of the following.

In a first case, the second session management function network element receives the first instruction, and learns that the first service of the remote UE needs to be switched to the second relay UE, so that the second session management function network element sends the second instruction to the second relay UE after the session of the interface between the second session management function network element and the second user plane function network element is established or modified.

In a second case, the second session management function network element receives the first indication to obtain the SSC =3 of the first service of the remote UE, so that the second session management function network element sends the second indication to the second relay UE after the session of the interface between the second session management function network element and the second user plane function network element is established or modified, which may be said to be that the first indication is used to indicate that the SSC mode of the first service is equal to 3.

In a third case, the second session management function network element receives the first indication to know that the first service of the remote UE needs the high-level service continuity, so that the second session management function network element sends the second indication to the second relay UE after the session of the interface between the second session management function network element and the second user plane function network element is established or modified, in this case, the first indication is also used to indicate that the first service needs the high-level service continuity.

In a fourth case, the second session management function network element receives the first instruction, learns that the remote UE needs to establish the IP address after the handover and then releases the IP address before the handover, and thus, after the session of the interface between the second session management function network element and the second user plane function network element is established or modified, the second session management function network element sends the second instruction to the second relay UE, in which case, it can also be said that the first instruction is used for instructing to establish the IP address after the handover and then release the IP address before the handover.

In a fifth case, the second session management function network element receives the first indication, learns that the remote UE needs to establish the PDU session address after the handover and then releases the PDU session before the handover, and thus, after the session of the interface between the second session management function network element and the second user plane function network element is established or modified, the second session management function network element sends the second indication to the second relay UE, in this case, the first indication is also used to indicate that the PDU session after the handover is established and then the PDU session before the handover is released.

Step 404, the second relay UE receives a second indication from the second session management function network element, where the second indication is used to indicate that the first service handover is successful.

Specifically, after the second relay UE completes the N4 session modification, the second session management function network element replies a second indication to the second relay UE to indicate that the first service is successfully switched, so as to notify the second relay UE that the PDU session requiring service continuity has been assisted by the network side, thereby obtaining the continuity guarantee of the application layer.

Step 405, the second relay UE sends a third instruction to the remote UE, where the third instruction is used to instruct to release the resource before the remote UE is handed over.

In other words, the above step 405 can be understood as a possible case as follows.

In a first possible situation, the second relay UE forwards a message that the first service switching from the second session management function network element is successful to the remote UE, where the message that the first service switching is successful is a third indication for indicating to release the resource before the remote UE is switched, and the remote UE releases the resource before the remote UE is switched according to the message, which can also be referred to as the message for indicating to release the resource before the remote UE is switched.

In a second possible case, the second relay UE sends a Dynamic Host Configuration Protocol (DHCP) release request message to the remote UE, where the DHCP release request message is a third indication for indicating to release the resource before the remote UE is switched, and the remote UE releases the resource before the remote UE is switched according to the DHCP release request, or the DHCP release request is used to indicate to release the resource before the remote UE is switched.

Under a third possible situation, because the second relay UE binds the identification information of the remote UE and the identification information of the first service, the second relay UE sends the identification information of the first service and the third indication to the remote UE, where the identification information of the first service is used to indicate that the switching of the first service is successful, and the remote UE releases resources before the switching of the remote UE according to the identification information of the first service and the third indication.

Step 406, the remote UE releases the resources before handover.

It should be noted that, assuming that the address allocated by the first relay UE to the remote UE is allocated in the granularity of the remote UE, the remote UE releases the resource of the remote UE before switching; it is assumed that the address allocated by the first relay UE to the remote UE is allocated with the service as granularity, and the remote UE releases the resource of the first service before the handover.

For the scenario shown in fig. 3A, there may be the following possible ways of releasing resources.

In the mode a, after the remote UE receives the third instruction, the remote UE determines the SMF1 network element and the UPF1 network element that are accessed before the handover, and the RAN1 notifies the SMF1 network element and the UPF1 network element on the network side of releasing the address and the port number/port range of the PDU session before the handover.

For the scenario shown in fig. 3B, there may be three possible ways of releasing resources as follows.

In the first mode, after the remote UE receives the third instruction, the remote UE determines the first relay UE connected before the handover, and releases the first address allocated to the remote UE by the first relay UE, or releases the first address allocated to the first service by the first relay UE. After the remote UE releases the first address, the first relay UE is notified that the first address of the first relay UE is released, so that the first relay UE can release the first address in time, or configure the first address to other remote UEs or other services.

In a second manner, after the remote UE receives the third instruction, the remote UE determines the first relay UE connected before handover, and sends a notification (for example, the notification is a DHCP release request) to the first relay UE, where the notification is used to notify the first relay UE to release the first address allocated to the remote UE or the first service. Then, after the first relay UE releases the first address, the remote UE is notified that the first address is released, so that the remote UE stops using the first address to perform data transmission of a service with the first relay UE, and in addition, the first relay UE may also notify the SMF1 network element and the UPF1 network element on the network side to release the second address and the port number/port range of the PDU session before handover.

In the embodiment of the present application, when a transmission path of a remote UE is switched, although the UE communicates with a network side server using a newly configured IP address after the switching, a session of an interface between a second session management function network element and a second user plane function network element is established or modified, and then resources before the switching are released, transmission of a service with high priority service continuity is not interrupted, that is, service transmission between the remote UE and the network server is not interrupted before and after the transmission path is switched, thereby ensuring service continuity.

Example two

Referring to fig. 5, a schematic flowchart of a second method for implementing service continuity provided in the embodiment of the present application is shown, where the method includes the following steps.

Step 501, the second relay UE receives a communication request message from the remote UE.

In one possible approach, the second relay UE receives the first communication request message and the second communication request message from the remote UE. The first communication request message is used for indicating that the first service of the remote UE is switched to the second relay UE, and the second communication request message is used for indicating that the second service of the remote UE is switched to the second relay UE.

Or the second relay UE receives a communication request message from the remote UE, where the communication request message is used to instruct the remote UE to switch the first service and the second service to the second relay UE.

It should be noted that the first service and the second service refer to different services, and in the second embodiment, the second relay UE may also receive other communication request messages from the remote UE, where the manner of switching between the multiple services of the remote UE is exemplarily illustrated only by the first service and the second service, and no limitation is made to the specific number of services.

The specific content of the second relay UE receiving the communication request message from the remote UE may refer to cases a to c in step 400, and the specific content of the second relay UE receiving the second communication request message from the remote UE is similar to the specific content of the first communication request message, and will not be described again here.

Step 502, the second relay UE sends a first indication to the second session management function network element and the third session management function network element. The first indication is used for indicating that the session of the first service of the interface between the second session management function network element and the second user plane function network element is established or modified and then sending a second indication; and the first indication is used for indicating the session establishment or modification of the second service of the interface between the third session management function network element and the third user plane function network element and then sending a fourth indication.

In other words, the step 502 above can be understood as two possible cases, that is, in the first case, the second relay UE sends an indication a to the second session management function network element and the third session management function network element, where the indication a is used for indicating that the session of the first service interfaced between the second session management function network element and the second user plane function network element is established or modified to send a second indication; and the second relay UE sends an indication B to the second session management function network element and the third session management function network element, wherein the indication B is used for indicating that the session of the second service of the interface between the third session management function network element and the third user plane function network element is established or modified and then sending a fourth indication. That is, the above-described indication a and indication B are collectively referred to as a first indication. In case two, the second relay UE sends a first indication to the second session management function network element and the third session management function network element, where the first indication is used for indicating both the information indicated by the indication a and the information indicated by the indication B.

It should be noted that the second session management function network element in the session of the first service and the third session management function network element in the session of the second service may be different session management function network elements or may be the same session management function network element; the second user plane functional network element in the session of the first service and the third user plane functional network element in the session of the second service may be different user plane functional network elements or the same user plane functional network element. That is, if the first service and the second service are managed by the same session management function network element, the first session management function network element and the second session management function network element are the same session management function network element; and if the first service and the second service are managed by different session management function network elements, the first session management function network element and the second session management function network element are different session management function network elements.

When the second relay UE determines that the SSC pattern of the first service is the third pattern and the SSC pattern of the second service is the third pattern, the first indication is sent to the first session management function network element, specifically, a case that the second relay UE is triggered to send the first indication to the second session management function network element and the third session management function network element may be referred to as any one of the following cases.

In case a, when the SSC of the first service carried in the message received by the second relay UE from the remote UE is the third mode, and the SSC mode of the second service is the third mode, that is, the value of the SSC mode of the first service is 3, and the value of the SSC mode of the second service is 3, because the third mode is used to represent that the first service and the second service require high-priority service continuity, the remote UE is allowed to establish a session anchor reaching the same DN before handover, and therefore the second relay UE sends the first indication to the second session management function and the third session management function network element.

In case B, the second relay UE determines that the SSC mode of the first service and the second service is the third mode according to the relay service identifier (relay service code) of the first service and the relay service identifier of the second service from the remote UE, so that the second relay UE sends the first indication to the second session management function network element and the third session management function network element.

Step 503, the second session management function network element establishes or modifies a session of the first service interfaced between the second session management function network element and the second user plane function network element, and the third session management function network element establishes or modifies a session of the second service interfaced between the third session management function network element and the third user plane function network element.

Specifically, the process of establishing or modifying the session of the first service may refer to step 403, and the process of establishing or modifying the session of the second service may refer to the first service, which is not repeated herein.

In step 504, the second relay UE receives a second indication from the second session management function network element, where the second indication is used to indicate that the first service handover is successful. And the second relay UE receives a fourth indication from the third session management function network element, wherein the fourth indication is used for indicating that the second service switching is successful.

Specifically, after the second relay UE completes the N4 session modification, the second session management function network element replies a second indication to the second relay UE to indicate that the first service is successfully switched; and after the second relay UE finishes the N4 session modification, the third session management function network element replies a fourth indication to the second relay UE to indicate that the second service is successfully switched. The second indication and the third indication are intended to inform the second relay UE that the PDU session requiring service continuity has been assisted by the network side, so that the continuity guarantee of the application layer can be obtained.

In a possible embodiment, if the remote UE further requests to switch another service before performing step 504, and the other service requires high priority service continuity, the second relay UE may wait for indication information of all services indicating successful switching of the PDU session corresponding to the service, and then perform step 505.

It should be noted that the second indication and the fourth indication may be carried in the same message, and the second relay UE may obtain the second indication and the fourth indication from the received message; the second indication and the fourth indication may be carried in different messages, and the second relay UE may obtain the second indication and the fourth indication from the received messages, respectively.

Step 505, the second relay UE sends a third instruction to the remote UE, where the third instruction is used to instruct to release the resource before the remote UE is handed over.

In other words, the second relay UE determines that both the first service and the second service of SSC =3 are successfully switched according to the second indication and the third indication in step 504, so the second relay UE transmits the third indication to the remote UE.

Specifically, the step 505 can be understood as multiple cases, and reference may be made to the first possible case to the third possible case shown in the step 405, which is not repeated herein.

In step 506, the remote UE releases the resources before handover.

It should be noted that, assuming that the address allocated by the first relay UE to the remote UE is allocated in the granularity of the remote UE, the remote UE releases the resource of the remote UE before switching; it is assumed that the address allocated by the first relay UE to the remote UE is allocated with the service as granularity, and the remote UE releases the resource of the first service and the resource of the second service before the handover.

Specifically, the resource release procedure before handover corresponding to the first service may refer to step 406, and the resource release procedure before handover corresponding to the second service is similar to that, so that details are not described herein again.

In the embodiment of the application, when a plurality of services required by high-priority service continuity are successfully switched, the remote UE releases resources before switching, and transmission of the high-priority service continuity service is not interrupted, that is, service transmission between the remote UE and the network server is not interrupted before and after switching of a transmission path, so that service continuity is ensured.

The above method is further illustrated below with reference to the scenario shown in fig. 3B. The process shown in fig. 6 corresponds to a PDU session establishment process before the handover of the remote UE, and the process shown in fig. 7A corresponds to a PDU session modification process after the handover of the remote UE.

As shown in fig. 6, the PDU session setup procedure before handover for the remote UE includes the following steps.

Step 600, a discovery procedure is executed between the remote UE and the first relay UE.

Step 601a, the remote UE sends an indirect communication request message to the first relay UE, where the indirect communication request message is used to instruct the remote UE to switch the first service to the second relay UE.

In a possible case, the indirect communication request message may be sent by the remote UE to the second relay UE, and is a request message used by the remote UE to request communication with the second relay UE, where the indirect communication request message carries a handover request indication, and the handover request indicates that the first service of the remote UE is handed over to the second relay UE.

Step 601b, after the first relay UE receives the indirect communication request message, a PC5 secure connection is established with the remote UE. Thereafter, the control plane information may be transferred between the remote UE and the first relay UE via the PC5 secure connection.

Step 601c, in one case, if the first relay UE determines that the local unavailable PDU session is served by the remote UE, the first relay UE may establish a PDU session corresponding to one service according to at least one of an identifier (S-NSSAI) of a network slice requested by the remote UE, a Data Network Name (DNN), or an SSC mode, for example, the first relay UE may establish a first PDU session corresponding to the identifier information of the first service. Wherein the first relay UE may obtain the above-mentioned S-NSSAI/DNN/SSC mode information in step 600 or step 601 a.

It should be noted that, the first relay UE may also infer the SSC mode requested by the remote UE through a relay service identifier (relay service code) of the first service; or the first relay UE may inform the first relay UE to request the corresponding SSC pattern this time after transmitting the first communication request message or after the secure PC5 connection is established.

In one possible scenario, if the first relay UE determines that no locally available PDU session serves the remote UE, the first relay UE creates a PDU session corresponding to the service one to one according to the S-NSSAI/DNN/SSC mode requested by the remote UE. In another case, if the first relay UE determines that the locally available PDU sessions serve the remote UE, the first relay UE modifies the PDU sessions corresponding to the services one by one according to the S-NSSAI/DNN/SSC mode requested by the remote UE.

Step 601d, after the first relay UE establishes the PDU session corresponding to the service, the first relay UE obtains the second IP address of the PDU session from the SMF1 network element through the AMF network element, and the second IP address is used for communication between the first relay UE and the PDU session anchor point or DN corresponding to the service.

Step 602, after the PC5 secure connection is successfully established, the remote UE initiates a DHCP process, and the first relay UE allocates a first IP address to the remote UE or the service. The first IP address is used for communication between the remote UE and the first relay UE.

Specifically, the first relay UE may configure the first address in any one of the following two manners, and establish the binding relationship in any one of the following two manners.

In the first mode, the first relay UE allocates a first IP address uniquely corresponding to the remote UE, and each remote UE is allocated a first IP address uniquely corresponding to the remote UE.

In the second mode, the first relay UE allocates a unique corresponding first IP address to each service of the remote UE, and each service of the remote UE is allocated a unique corresponding first IP address. In addition, the first relay UE assigns a port number/port range for the far-end UE to communicate with the PDU session anchor or DN on the second IP address.

Step 603, the first relay UE performs a binding relationship among the identification information of the remote UE, the first IP address, the second IP address, the port number/port range, and the identification of the PDU session.

In case a, it is assumed that the second relay UE allocates the IP address to the remote UE is allocated by using the remote UE as a granularity, when each remote UE uniquely corresponds to one IP @1, if the UE has at least one service, where the at least one service includes the first service, each service has the identification information of the PDU session uniquely corresponding to the service, the second IP address of the PDU session, the port number/port range, and the SSC pattern, as exemplarily shown in table 3.

TABLE 3

In case B, it is assumed that the second relay UE allocates the IP address to the remote UE using the services as the granularity, and the second relay UE allocates a first IP address uniquely corresponding to each service of each remote UE, if the UE has at least one service, where the at least one service includes the first service, each service has identification information of a PDU session uniquely corresponding to the first service, a second IP address of the PDU session, a port number/port range, and an SSC pattern, as exemplarily shown in table 4.

TABLE 4

Step 604, the first relay UE notifies the SMF1 network element of the binding relationship between the identification information of the remote UE, the second IP address, and the port number/port range, or the first relay UE notifies the SMF1 network element of the binding relationship between the identification information of the remote UE, the identification information of the PDU session, the second IP address, and the port number/port range.

Step 605, the smf1 network element finds one or more corresponding UPF1 network elements according to the correspondence between the second IP address or the PDU session identifier and the N4 session ID, initiates an N4 session establishment or modification procedure to the one or more UPF1 network elements, and saves the port number/port range in the PDR.

As shown in fig. 7A, the PDU session establishment or modification procedure includes the following steps at handover time of the remote UE. In the embodiment of the present application, it is assumed that in a scenario where both the first service and the second service are switched, session management functions of both the first service and the second service are managed by an SMF2, and user plane functions of both the first service and the second service are managed by an UPF 2.

Step 700, before the far-end UE switches the transmission path, the far-end UE connects to the network through the first relay UE.

Specifically, the remote UE may establish a connection with the first relay UE through the method shown in fig. 6, and the first relay UE establishes a PDU session with the network side.

Step 701, when the remote UE finds that the communication quality is not good or degrades and cannot meet the current service requirement, the remote UE performs relay reselection, finds a second relay UE, and sends a first communication request message to the second relay UE, where the first communication request message is used to request the first service to be switched to the second relay UE, or the first communication request message is used to request the first service and the second service to be switched to the second relay UE.

Step 702, the remote UE establishes a PC5 link with the second relay UE, and the second relay UE allocates a third address to the remote UE, or the second relay UE allocates third addresses to the first service and the second service, respectively.

In step 703, in one case, if the second relay UE determines that there is no PDU session corresponding to the service locally, the second relay UE may establish a PDU session corresponding to the service one by one according to the S-NSSAI/DNN/SSC mode requested by the remote UE, for example, the second relay UE may establish a first PDU session corresponding to the identification information of the first service, and the second relay UE may establish a second PDU session corresponding to the identification information of the second service. Wherein the second relay UE may obtain the above-mentioned S-NSSAI/DNN/SSC mode information in step 701 or step 702.

In another case, if the second relay UE determines that the locally available PDU session serves the remote UE, the second relay UE modifies the PDU session corresponding to the service one to one according to the S-NSSAI/DNN/SSC mode requested by the remote UE. The second relay requests the SMF2 network element (corresponding to the above second Session management class function network element) to establish or modify the PDU Session for the remote UE, and after the SMF2 establishes or modifies the PDU Session, the identification information of the PDU Session (PDU Session ID) and the fourth address of the PDU Session are allocated to the PDU Session. In addition, the second relay UE allocates a port number/port range (port number) for the remote UE to communicate with the PDU session anchor point or DN at the fourth address.

And then, the second relay UE establishes a binding relationship among the identification information of the remote UE, the fourth address and the port number/port range, or the second relay UE establishes a mapping relationship among the identification information of the remote UE, the identification information of the PDU session and the port number/port range. For specific examples, see table 1 and table 2 above, and detailed descriptions thereof are not repeated here.

In step 704, the second relay UE sends the first indication, the identity of the remote UE, the identity of the PDU session, the fourth IP address and the port number/port range to SMF 2.

When the second relay UE determines that the SSC mode of the service to be switched is the third mode, it sends a first indication to the first session management function network element, and the condition that the second relay UE is triggered to send the first indication to the second session management function network element may refer to any one of the conditions a to C in step 402. Specifically, in a scenario that a service to be switched is a first service, the first indication may be used to indicate that the first service of the remote UE is switched to the second relay UE, or the first indication is used to indicate that the SSC pattern of the first service is equal to 3, or the first indication is used to indicate that the first service requires a high-level service continuity, or the first indication is used to indicate that the IP address after switching is established before switching is released. See in particular the four possible cases shown in example one.

In a scenario that a service to be switched is a first service and a second service, the first indication may be used to indicate that the first service and the second service of the remote UE are switched to the second relay UE, or the first indication is used to indicate that the SSC patterns of the first service and the second service are both equal to 3, or the first indication is used to indicate that the first service and the second service require high-level service continuity, and then the first indication is used to indicate that an IP address after switching is established before switching is released.

Step 705, the smf2 network element finds at least one corresponding UPF2 network element according to the fourth address or the corresponding relationship between the PDU session identifier and the N4 session ID, and initiates an N4 session modification procedure to the UPF2 network element, and saves the port number/port range in the PDR.

Step 706, after the N4 session modification is performed, the SMF2 network element sends a second indication for indicating that the first service is successfully switched to the second relay UE.

In a possible embodiment, if the first communication request message is further used to request the second service to be switched to the second relay UE in step 701, or the second communication request message is further received in step 701 to request the second service to be switched to the second relay UE, the SMF2 network element sends a fourth indication for indicating that the second service is successfully switched to the second relay UE.

Step 707, after the second relay UE receives the third indication and the fourth indication of the first service and the second service, the second relay UE notifies the remote UE to release the resource before the handover.

In other words, after the second relay UE determines that all services requiring high priority service continuity are successfully switched, the second relay UE notifies the remote UE to release resources before switching.

The manner of the second relay UE notifying the remote UE to release the resource before handover may refer to three possible cases in step 405.

There are various ways to release the resources before the handover, as shown in the figure.

The first method is as follows:

step 708a, the remote UE sends a DHCP release request or a handover success notification to the first relay UE, for notifying the first relay UE to release the IP address allocated to the remote UE or the service.

In step 709a, after receiving the DHCP release request or the handover success notification, the first relay UE releases the IP address allocated to the remote UE or the service.

The second method comprises the following steps:

in step 708b, the remote UE releases the first address (ip @1 shown in table 3) allocated for the remote UE or the service.

Specifically, reference may be made to the foregoing step 406, and details of three possible resource releasing manners for the scenario shown in fig. 3B are not repeated herein.

Step 710, the first relay UE determines the SMF1 and the UPF1 corresponding to the session according to the binding relationship established before, so that the first relay notifies the SMF1 and the UPF1 to release the second address (ip @2 shown in table 3) and the port number/port range (port 1 shown in table 3) of the PDU session, so that the downlink data of the remote UE is not transmitted through the second address and the port number any more, and the transmission path of the remote UE before the handover is disconnected.

In the embodiment of the application, the method can realize that the previous session is disconnected after the service switching of the remote UE is successful, thereby ensuring the service continuity of the remote UE, and in addition, the resources are released in time after the switching is completed before the switching of the remote UE, so as to improve the resource utilization rate.

In a possible embodiment, assuming that the transmission path of the remote UE is managed by the same SMF network element before and after the handover, and managed by the same UPF network element before and after the handover, referring to fig. 7B, before the handover, the remote UE accesses the network through the first relay UE. The first relay UE establishes a PDU conversation corresponding to the first service, the first relay UE allocates a first IP address (IP @1 as shown in the figure) for the far-end UE, the first relay UE acquires a second IP address (IP @2 as shown in the figure) of the first PDU conversation from the SMF network element, and the first relay allocates a first port number/port range which is communicated with a PDU conversation anchor point or DN on the second IP address for the far-end UE. The first relay establishes a binding relationship among the identification information of the remote UE, the first IP address, the second IP address, the identification information of the first PDU session and the first port number/port range. In addition, the SMF network element establishes the binding relationship among the identification information of the remote UE, IP @2, the identification information of the first PDU session and the first port number/port range through the information acquired from the first relay UE.

After the remote UE is handed over, the remote UE accesses the network through the second relay UE. The second relay UE modifies the first PDU session corresponding to the first service, the second relay UE allocates a third IP address (IP @1#, as shown in the figure) to the remote UE, the second relay UE acquires a fourth IP address (IP @2#, as shown in the figure) of the modified first PDU session from the SMF network element, and the second relay allocates a second port number/port range which is communicated with a PDU session anchor point or DN on the fourth IP address to the remote UE. The second relay establishes a binding relationship among the identification information of the remote UE, the third IP address, the fourth IP address, the identification information of the first PDU session and the second port number/port range. In addition, the SMF network element establishes a binding relationship between the identification information of the remote UE, ip @2#, the identification information of the first PDU session, and the second port number/port range, through a message acquired from the second relay UE. And then, the second relay UE informs the remote UE to release the switched resources. And after receiving the notification, the remote UE notifies the first relay UE to release the first IP address, and the first relay UE releases the switching binding relationship through the SMF network element.

Thus, for the far-end UE, before and after the transmission path of the far-end UE is switched, the session corresponding to the service of the far-end UE is established or modified, and then the resource before the switching is released, and the transmission of the service with high priority service continuity is not interrupted, that is, the service transmission between the far-end UE and the network server is not interrupted before and after the transmission path is switched, thereby ensuring the service continuity.

EXAMPLE III

Referring to fig. 8, a flow diagram of a third method for implementing service continuity according to the embodiment of the present application is provided, where a transmission path of a remote UE is managed by a same UDM network element or a Unified Data Repository (UDR) before and after handover, and the method includes the following steps.

Step 801, the UDM or the UDR determines that a session management function network element serving a first service of the remote UE is switched from a first session management function network element to a second session management function network element.

Specifically, before handover, the remote UE accesses the network through the first relay UE, the first relay UE reports the relevant information of the first service before handover to the first session management functional network element, the first session management functional network element reports the relevant information of the first service to the UDM or the UDR, and the UDM or the UDR further adds the identifier of the first session management functional network element and the identifier of the first relay UE in the relevant information of the first service, for example, the relevant information of the first service before handover stored in the UDM or the UDR is shown in table 5.

TABLE 5

After the handover, the remote UE accesses the network through the second relay UE, the second relay UE reports the relevant information of the handed first service to the second session management function network element, the second session management function network element reports the relevant information of the first service to the UDM or the UDR, and the UDM or the UDR further adds the identifier of the second session management function network element and the identifier of the second relay UE in the relevant information of the first service, for example, the relevant information of the handed first service stored in the UDM or the UDR is shown in table 6.

TABLE 6

In the first mode, the UDM or the UDR determines that the session management function network element serving the first service of the remote UE is switched from the first session management function network element to the second session management function network element according to the identification information of the first session management function network element corresponding to the relevant information of the first service and the identification information of the second session management function network element corresponding to the relevant information of the first service. Illustratively, the UDM or UDR determines that the session management function network element of the first service is switched from the first session management function network element to the second session management function network element according to the identifier of the SMF network element in table 5 and table 6.

And in the second mode, the UDM or the UDR determines that the relay UE serving the remote UE is switched according to the identification information of the first relay UE corresponding to the relevant information of the first service and the identification information of the second relay UE corresponding to the relevant information of the first service, so that the UDM or the UDR determines a first session management function network element and a second session management function network element serving the remote UE before and after switching according to the identification or the port number of the remote UE and the like.

Step 802, the udm or UDR sends a first notification to the first session management function network element, the first notification notifying the first session management function network element that the first service is no longer being provided to the remote UE.

In other words, the UDM or UDR instructs the first session management function network element to release the downstream data stream received by the port number allocated before the handover.

Step 803, the first session management function network element releases the resource before the remote UE is handed over.

Specifically, the first session management function network element releases the IP address allocated for the PDU session of the first service.

Step 804, the first session management function network element notifies the user plane function network element and the first relay UE to release the resource before the remote UE is switched from the first relay UE to the second relay UE.

Specifically, the first session management function network element notifies the user plane function network element to release the port number information allocated to the first service of the first relay UE. In addition, the first session management function network element notifies the first relay UE to release the first address, and after receiving the notification, the first relay UE releases the first address and port number information allocated to the remote UE by the remote UE.

In the embodiment of the present application, the difference from the first embodiment and the second embodiment is that the release process of the resources before the handover is triggered by the network side, although the remote UE accesses the relay UE to perform the handover, the resources before the handover are still released after the session is established or modified, and the transmission of the service with high priority service continuity is not interrupted, that is, the service transmission between the remote UE and the network server is not interrupted before and after the transmission path is switched, thereby ensuring the service continuity.

The above method is further illustrated below with reference to the scenario shown in fig. 3B. The process shown in fig. 9 corresponds to a PDU session establishment process before the handover of the remote UE, and the process shown in fig. 10 corresponds to a PDU session modification process after the handover of the remote UE.

As shown in fig. 9, the PDU session setup procedure before handover for the remote UE includes the following steps.

Steps 900 to 905 are the same as steps 601 to 605 shown in fig. 6.

In step 906, the SMF1 network element reports the obtained binding relationship of the first service to the UDM, for example, the SMF1 network element reports the identification information of the remote UE, the second IP address, the port number/port range, the identification of the PDU session, and the like to the UPF1 network element.

In step 907, the udm adds the identification of the SMF1 serving this PDU session and the identification information of the first relay UE on the basis of the binding.

As shown in fig. 10, the PDU session setup modification procedure at handover of the remote UE includes the following steps.

Step 1000, when the connection is established between the remote UE and the second relay UE, the communication request message sent by the remote UE to the second relay UE may not indicate that the communication request message is a handover request.

Steps 1001 to 1005 are the same as steps 701 to 705 shown in fig. 7A.

In step 1006, the SMF2 network element reports the obtained binding relationship of the first service to the UDM, for example, the SMF2 network element reports the identification information of the remote UE, the fourth IP address, the port number/port range, the identification of the PDU session, and the like to the UPF2 network element.

Step 1007, the udm adds the identification of the SMF2 serving this PDU session, and the identification information of the second relay UE, on the basis of the binding relationship.

In step 1008, if the UDM determines that the identity of the relay UE serving the remote UE has changed, the UDM determines the SMF1 corresponding to the identity of the remote UE. The UDM notifies the SMF1 network element that the first relay UE does not need to continue to provide service for the first service of the remote UE, for example, the UDM sends a "relay service change indication" to the SMF1 network element, where the "relay service change indication" is used to notify the SMF1 network element that the relay UE of the remote UE changes.

In step 1009, after the smf1 network element receives the "relay service change indication", it determines the identifier and port number of the PDU session corresponding to the first relay UE, and notifies the port number to the UPF2 network element through the N4 session, so that the UPF2 network element releases the downlink data stream received by the port range.

In step 1010, the smf1 network element notifies the first relay UE1 that the remote UE served by the identification of its PDU session has changed the relay, and the first relay UE1 needs to release the IP address allocated to the remote UE.

In step 1011, the first relay UE releases the first IP address.

For the first to third embodiments, it should be noted that: (1) The first embodiment and the third embodiment may be implemented separately in different scenarios, or may be implemented in combination in the same scenario, or different schemes involved in different embodiments may be implemented in combination (for example, some or all of the schemes involved in the first embodiment may be implemented in combination with the third embodiment), and are not limited specifically.

(2) The step number of each flowchart described in this embodiment of the present application is only one example of an execution flow, and does not limit the execution sequence of the steps, and there is no strict execution sequence between steps that have no time sequence dependency relationship between them in this embodiment of the present application.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.

The above-mentioned scheme provided by the embodiment of the present application is introduced mainly from the perspective of interaction between a network device and a terminal device. It is understood that, in order to implement the above functions, the network device or the terminal device may include a corresponding hardware structure and/or software module for performing each function. Those of skill in the art will readily appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as hardware or combinations of hardware and computer software. Whether a function is performed as hardware or computer software drives hardware depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

In the embodiment of the present application, the terminal device and the network device may be divided into the functional units according to the above method examples, for example, each functional unit may be divided corresponding to each function, or two or more functions may be integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

In case of integrated units, fig. 11 shows a possible exemplary block diagram of the devices involved in the embodiments of the present application. As shown in fig. 11, the apparatus 1100 may include: a processing unit 1102 and a communication unit 1103. The processing unit 1102 is configured to control and manage operations of the apparatus 1100. The communication unit 1103 is used to support communication of the apparatus 1100 with other devices. Optionally, the communication unit 1103, also referred to as a transceiving unit, may comprise a receiving unit and/or a transmitting unit for performing receiving and transmitting operations, respectively. The apparatus 1100 may further comprise a storage unit 1101 for storing program codes and/or data of the apparatus 1100.

The apparatus 1100 may be the remote UE in any of the above embodiments, or may also be a chip disposed in the remote UE. The processing unit 1102 may enable the apparatus 1100 to perform the actions of the remote UE in the above various method examples. Alternatively, the processing unit 1102 mainly performs the internal actions of the remote UE in the method example, and the communication unit 1103 may support communication between the apparatus 1100 and a relay device (e.g., a second relay UE).

The apparatus 1100 may be the second relay UE in any of the embodiments described above, or may also be a chip disposed in the second relay UE. The processing unit 1102 may enable the apparatus 1100 to perform the actions of the second relay UE in the above method examples. Alternatively, the processing unit 1102 mainly performs the internal actions of the second relay UE in the method example, and the communication unit 1103 may support communication between the apparatus 1100 and a network device (e.g., a second session management function network element).

The apparatus 1100 may be the first relay UE in any of the embodiments described above, or may also be a chip disposed in the first relay UE. The processing unit 1102 may enable the apparatus 1100 to perform the actions of the first relay UE in the above method examples. Alternatively, the processing unit 1102 mainly performs the internal actions of the first relay UE in the method example, and the communication unit 1103 may support communication between the apparatus 1100 and a network device (e.g., a first session management function network element).

The apparatus 1100 may be a network device (e.g., a first session management function network element, a second session management function network element, a unified data management network element, a unified data storage) in any of the above embodiments, or may also be a chip disposed in a network device (e.g., a second session management function network element, a unified data management network element, a unified data storage). The processing unit 1102 may enable the apparatus 1100 to perform the actions of the network device in the above method examples. Alternatively, the processing unit 1102 mainly performs internal actions of the network device in the method example, and the communication unit 1103 may support communication between the apparatus 1100 and the network device.

It should be understood that the division of the units in the above apparatus is only a division of logical functions, and the actual implementation may be wholly or partially integrated into one physical entity or may be physically separated. And the units in the device can be realized in the form of software called by the processing element; or may be implemented entirely in hardware; part of the units can also be realized in the form of software called by a processing element, and part of the units can be realized in the form of hardware. For example, each unit may be a processing element separately set up, or may be implemented by being integrated into a chip of the apparatus, or may be stored in a memory in the form of a program, and a function of the unit may be called and executed by a processing element of the apparatus. In addition, all or part of the units can be integrated together or can be independently realized. The processing element described herein may in turn be a processor, which may be an integrated circuit having signal processing capabilities. In the implementation process, the steps of the method or the units above may be implemented by integrated logic circuits of hardware in a processor element or in a form called by software through the processor element.

In one example, the units in any of the above apparatus may be one or more integrated circuits configured to implement the above method, for example: one or more Application Specific Integrated Circuits (ASICs), or one or more microprocessors (DSPs), or one or more Field Programmable Gate Arrays (FPGAs), or a combination of at least two of these Integrated Circuit formats. For another example, when a unit in the apparatus can be implemented in the form of a processing element scheduler, the processing element may be a processor, such as a Central Processing Unit (CPU), or other processor capable of calling a program. As another example, these units may be integrated together and implemented in the form of a system-on-a-chip (SOC).

The above unit for receiving is an interface circuit of the apparatus for receiving signals from other apparatuses. For example, when the device is implemented in the form of a chip, the receiving unit is an interface circuit for the chip to receive signals from other chips or devices. The above unit for transmitting is an interface circuit of the apparatus for transmitting a signal to other apparatuses. For example, when the device is implemented in the form of a chip, the transmitting unit is an interface circuit for the chip to transmit signals to other chips or devices.

Please refer to fig. 12, which is a schematic structural diagram of a remote UE or a second relay UE according to an embodiment of the present application. It may be the remote UE or the second relay UE in the above embodiments, and is used to implement the operation of the remote UE or the second relay UE in the above embodiments. As shown in fig. 12, the remote UE or the second relay UE includes: an antenna 1210, a radio frequency part 1220, a signal processing part 1230. The antenna 1210 is connected to the radio frequency part 1220. In the downlink direction, the rf part 1220 receives information transmitted from the network device through the antenna 1210, and transmits the information to the signal processing part 1230 for processing. In the uplink direction, the signal processing portion 1230 processes the information of the remote UE or the second relay UE and sends the processed information to the radio frequency portion 1220, and the radio frequency portion 1220 processes the information of the remote UE or the second relay UE and sends the processed information to the network device through the antenna 1210.

The signal processing portion 1230 may include a modem subsystem for implementing processing of various communication protocol layers of data; and the system also comprises a central processing subsystem which is used for realizing the processing of the operating system and the application layer of the remote UE or the second relay UE.

The modem subsystem may include one or more processing elements 1231, including, for example, a master CPU and other integrated circuits. The modem subsystem may also include a storage element 1232 and an interface circuit 1233. The storage element 1232 is used to store data and programs, but the programs for executing the methods executed by the remote UE or the second relay UE in the above methods may not be stored in the storage element 1232, but stored in a memory outside the modem subsystem, and loaded for use by the modem subsystem when in use. The interface circuit 1233 is used to communicate with other subsystems.

The modem subsystem may be implemented by a chip including at least one processing element for performing the steps of any of the above methods performed by the remote UE or the second relay UE, and interface circuitry for communicating with other devices. In one implementation, the unit for the remote UE or the second relay UE to implement each step in the above method may be implemented in the form of a processing element scheduler, for example, an apparatus for the remote UE or the second relay UE includes a processing element and a storage element, and the processing element calls the program stored in the storage element to execute the method executed by the remote UE or the second relay UE in the above method embodiment. The memory elements may be memory elements with the processing elements on the same chip, i.e. on-chip memory elements.

In another implementation, the program for performing the method performed by the remote UE or the second relay UE of the above methods may be in a memory element on a different chip than the processing element, i.e., an off-chip memory element. At this time, the processing element calls or loads a program from the off-chip storage element onto the on-chip storage element to call and execute the method executed by the remote UE or the second relay UE in the above method embodiment.

In yet another implementation, the unit for the remote UE or the second relay UE to implement the steps of the above method may be configured as one or more processing elements disposed on the modem subsystem, where the processing elements may be integrated circuits, for example: one or more ASICs, or one or more DSPs, or one or more FPGAs, or a combination of these types of integrated circuits. These integrated circuits may be integrated together to form a chip.

The units of the remote UE or the second relay UE implementing the steps of the above method may be integrated together and implemented in the form of an SOC chip for implementing the above method. At least one processing element and a storage element can be integrated in the chip, and the processing element calls the form of a stored program of the storage element to realize the method executed by the remote UE or the second relay UE; or, at least one integrated circuit may be integrated in the chip, for implementing the above method performed by the remote UE or the second relay UE; alternatively, the above implementation modes may be combined, the functions of the partial units are implemented in the form of a processing element calling program, and the functions of the partial units are implemented in the form of an integrated circuit.

It can be seen that the apparatus for the remote UE or the second relay UE above may comprise at least one processing element and interface circuitry, wherein the at least one processing element is configured to perform the method performed by any one of the remote UE or the second relay UE provided in the method embodiments above. The processing element may: namely, calling a program stored in the storage element to execute part or all of the steps executed by the remote UE or the second relay UE; it is also possible in a second way: that is, some or all of the steps performed by the remote UE or the second relay UE are performed by integrated logic circuitry of hardware in the processor element in combination with the instructions; of course, some or all of the steps performed by the remote UE or the second relay UE may also be performed in combination with the first manner and the second manner.

The processing elements herein, like those described above, may be implemented by a processor, and the functions of the processing elements may be the same as those of the processing unit described in fig. 9. Illustratively, the processing element may be a general-purpose processor, such as a CPU, and may also be one or more integrated circuits configured to implement the above methods, such as: one or more ASICs, or one or more microprocessors DSP, or one or more FPGAs, etc., or a combination of at least two of these integrated circuit forms. The memory element may be implemented by a memory, and the function of the memory element may be the same as that of the memory cell described in fig. 9. The memory elements may be implemented by memory, and the function of the memory elements may be the same as that of the memory cells described in fig. 9. The storage element may be a single memory or a combination of memories.

The remote UE shown in fig. 12 is capable of implementing various processes involving the remote UE in the method embodiments illustrated in fig. 4 to 10. The operations and/or functions of the respective modules in the remote UE shown in fig. 12 are respectively for implementing the corresponding flows in the above method embodiments. The second relay UE shown in fig. 12 is capable of implementing various procedures involving the second relay UE in the method embodiments illustrated in fig. 4 to 10. The operations and/or functions of the respective modules in the second relay UE shown in fig. 12 are respectively for implementing the corresponding flows in the above method embodiments. Specifically, reference may be made to the description of the above method embodiments, and the detailed description is appropriately omitted herein to avoid redundancy.

Please refer to fig. 13, which is a schematic structural diagram of a network device (e.g., a first session management function network element, a second session management function network element, a unified data management network element, and a unified data storage) according to an embodiment of the present application. For implementing the operations of the network devices (e.g. the first session management function network element, the second session management function network element, the unified data management network element, the unified data storage) in the above embodiments. As shown in fig. 13, the network device includes: antenna 1301, radio frequency device 1302, baseband device 1303. The antenna 1301 is connected to the radio frequency device 1302. In the uplink direction, the rf device 1302 receives information sent by the remote UE or the second relay UE through the antenna 1301, and sends the information sent by the remote UE or the second relay UE to the baseband device 1303 for processing. In the downlink direction, the baseband device 1303 processes information of the remote UE or the second relay UE and sends the information to the radio frequency device 1302, and the radio frequency device 1302 processes the information of the remote UE or the second relay UE and sends the information to the remote UE or the second relay UE via the antenna 1301.

Baseband device 1303 may include one or more processing elements 13031, e.g., including a host CPU and other integrated circuits. In addition, the baseband device 1303 may further include a storage element 13032 and an interface 13033, where the storage element 13032 is used for storing programs and data; the interface 13033 is used for exchanging information with the radio frequency device 1302, and is, for example, a Common Public Radio Interface (CPRI). The above means for a network device may be located on the baseband means 1303, for example, the above means for a network device may be a chip on the baseband means 1303, the chip including at least one processing element and an interface circuit, wherein the processing element is configured to perform each step of any one of the methods performed by the above network device, and the interface circuit is configured to communicate with other devices. In one implementation, the unit of the network device implementing each step in the above method may be implemented in the form of a processing element scheduler, for example, an apparatus for the network device includes a processing element and a storage element, and the processing element calls a program stored in the storage element to execute the method executed by the network device in the above method embodiment. The memory elements may be memory elements on the same chip as the processing element, i.e. on-chip memory elements, or may be memory elements on a different chip than the processing element, i.e. off-chip memory elements.

In another implementation, the unit of the network device for implementing the steps of the above method may be configured as one or more processing elements, which are disposed on the baseband apparatus, where the processing elements may be integrated circuits, for example: one or more ASICs, or one or more DSPs, or one or more FPGAs, or a combination of these types of integrated circuits. These integrated circuits may be integrated together to form a chip.

The units of the network device implementing the steps of the above method may be integrated together and implemented in the form of a system-on-a-chip (SOC), for example, a baseband device including the SOC chip for implementing the above method. At least one processing element and a storage element can be integrated in the chip, and the method executed by the network equipment is realized in the form that the processing element calls the stored program of the storage element; or, at least one integrated circuit may be integrated in the chip, for implementing the method executed by the above network device; alternatively, the above implementation modes may be combined, the functions of the partial units are implemented in the form of a processing element calling program, and the functions of the partial units are implemented in the form of an integrated circuit.

It is seen that the above apparatus for a network device may comprise at least one processing element and interface circuitry, wherein the at least one processing element is configured to perform the method performed by any one of the network devices provided by the above method embodiments. The processing element may: namely, calling the program stored in the storage element to execute part or all of the steps executed by the network equipment; it is also possible to: that is, some or all of the steps performed by the network device are performed by integrated logic circuitry of hardware in the processor element in combination with the instructions; of course, some or all of the steps performed by the above network device may also be performed in combination with the first manner and the second manner.

The processing elements herein, like those described above, may be implemented by a processor, and the functions of the processing elements may be the same as those of the processing unit described in fig. 10. Illustratively, the processing element may be a general-purpose processor, such as a CPU, and may also be one or more integrated circuits configured to implement the above methods, such as: one or more ASICs, or one or more microprocessors DSP, or one or more FPGAs, etc., or a combination of at least two of these integrated circuit forms. The memory elements may be implemented by memory, and the function of the memory elements may be the same as that of the memory cells described in FIG. 11. The memory elements may be implemented by memory, and the function of the memory elements may be the same as that of the memory cells described in FIG. 11. The storage element may be a single memory or a combination of memories.

The network device shown in fig. 13 can implement the processes related to the network device in the above method embodiments. The operations and/or functions of the respective modules in the network device shown in fig. 13 are respectively for implementing the corresponding flows in the above-described method embodiments. Specifically, reference may be made to the description of the above method embodiments, and the detailed description is appropriately omitted herein to avoid redundancy.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

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.

Claims

1. A method for implementing service continuity, comprising:

a second relay User Equipment (UE) receives a first communication request message from a remote UE, wherein the first communication request message is used for indicating that a first service of the remote UE is switched to the second relay UE;

the second relay UE sends a first indication to a second session management function network element, the first indication is used for indicating that a session of an interface between the second session management function network element and a second user plane function network element is established or modified and then sending a second indication, and the second indication is used for indicating that the first service is successfully switched;

the second relay UE receiving the second indication from the second session management function network element;

and the second relay UE sends a third instruction to the remote UE, wherein the third instruction is used for instructing the release of the resources before the remote UE is switched.

2. The method of claim 1, further comprising:

the second relay UE binds the identification information of the remote UE and the identification information of the first service;

and the second relay UE sends the identification information of the first service to the remote UE, wherein the identification information of the first service is used for indicating that the first service is successfully switched.

3. The method of claim 1, wherein the third indication is used for indicating that resources before the handover of the remote UE are released comprises: the third indication is used for indicating to release the resource of the first service before the far-end UE is switched.

4. The method of claim 2, further comprising:

the second relay UE determines a Session and Service Continuity (SSC) pattern of the first traffic as a third pattern, wherein the third pattern is used for representing a traffic continuity requirement that the first traffic has a high priority.

5. The method of claim 4,

the second relay UE determines the SSC mode to be a third mode according to the relay service identification of the first service from the remote UE;

or, the second relay UE determines that the SSC pattern is a third pattern according to the type of the first communication request message being a handover request;

or, the second relay UE determines that the SSC pattern is the third pattern according to indication information in a message from the remote UE, where the indication information is used to indicate that the SSC pattern of the first service is the third pattern.

6. The method of claim 1, wherein the first communication request message is used for instructing the far-end UE to switch the first traffic to the second relay, and comprises: the first communication request message is used for indicating that the first service and the second service of the remote UE are switched to the second relay UE;

alternatively, the method further comprises:

and the second relay UE receives a second communication request message from the remote UE, wherein the second communication request message is used for indicating that a second service of the remote UE is switched to the second relay UE.

7. The method of claim 6, wherein the first indication is further used to indicate that a session between the second session management function network element and the user plane function network element is established or modified, and then a fourth indication is sent, where the fourth indication is used to indicate that the second service handover is successful;

the method further comprises the following steps:

the second relay UE receiving a fourth indication from a second session management function network element;

the second relay UE sending a third indication to the remote UE includes:

when the second relay UE receives the second indication and the fourth indication, the second relay UE sends a third indication to the remote UE.

8. The method of claim 7, further comprising:

the second relay UE determines that the SSC mode of the first service and the SSC mode of the second service are both in a third mode, wherein the third mode is used for representing that the first service needs high-priority service continuity.

9. The method according to any of claims 1 to 8, wherein before the second relay UE sends the first indication to the second Session management function network element, the method further comprises:

the second relay UE establishes or modifies a Protocol Data Unit (PDU) session for the first service;

the second relay UE receiving a fourth address of the PDU session from a second session management function network element;

and the second relay UE allocates a port number used for transmitting the data of the first service on the fourth address to the remote UE.

10. The method of claim 9, further comprising:

and the second relay UE sends the identification information of the remote UE, the fourth address and the port number to the second session management function network element, or sends the identification information of the remote UE, the identification information of the PDU session and the port number.

11. A communication apparatus, comprising a communication unit;

the communication unit is configured to receive a first communication request message from a remote user equipment UE, where the first communication request message is used to instruct the remote UE to switch a first service to a second relay UE;

the communication unit is further configured to send a first instruction to a second session management function network element, where the first instruction is used to instruct a session establishment or a modification of an interface between the second session management function network element and a second user plane function network element to send a second instruction, and the second instruction is used to instruct that the first service is successfully switched;

the communication unit is further configured to receive the second indication from the second session management function network element;

the communication unit is further configured to send a third indication to the remote UE, where the third indication is used to indicate to release the resource before the remote UE is handed over.

12. The communication device of claim 11, further comprising a processing unit;

the processing unit is configured to bind the identifier information of the remote UE and the identifier information of the first service;

the communication unit is further configured to send identifier information of the first service to the remote UE, where the identifier information of the first service is used to indicate that the first service is successfully switched.

13. The communications apparatus of claim 11, wherein the third indication is used to indicate that resources before the handover of the remote UE are released comprises: the third indication is used for indicating to release the resource of the first service before the far-end UE is switched.

14. The communications device of claim 12, wherein the processing unit is further configured to determine a Session and Service Continuity (SSC) pattern of the first traffic as a third pattern, wherein the third pattern is used to characterize a traffic continuity requirement that the first traffic has a high priority.

15. The communications apparatus of claim 14, wherein the processing unit is further configured to:

determining the SSC mode as a third mode according to a relay service identification of the first service from a remote UE;

or, determining the SSC mode as a third mode according to the type of the first communication request message as a switching request;

or, determining the SSC pattern to be the third pattern according to indication information in a message from the remote UE, where the indication information is used to indicate that the SSC pattern of the first service is the third pattern.

16. The communications apparatus of claim 11, wherein the first communication request message is used to instruct the remote UE to switch the first traffic to the second relay, and comprises: the first communication request message is used for indicating that the first service and the second service of the remote UE are switched to the second relay UE;

or, the communication unit is further configured to: and receiving a second communication request message from the remote UE, wherein the second communication request message is used for indicating that a second service of the remote UE is switched to the second relay UE.

17. The communications apparatus according to claim 16, wherein the first indication is further configured to indicate that a session between the second session management function network element and the user plane function network element is established or modified, and then send a fourth indication, where the fourth indication is used to indicate that the second service handover is successful;

the communication unit is further configured to: receiving a fourth indication from the second session management function network element;

the communication unit sending a third indication to the remote UE comprises:

when the communication unit receives the second indication and the fourth indication, a third indication is sent to the far-end UE.

18. The communications device of claim 17, wherein the processing unit is further configured to:

determining that the SSC pattern of the SSC of the first service is a third pattern, wherein the third pattern is used for representing that the first service needs high-priority service continuity.

19. The communication device according to any of claims 11 to 18, wherein before the communication unit sends the first indication to the second session management function network element, the processing unit is further configured to:

establishing or modifying a Protocol Data Unit (PDU) session for the first service;

the communication unit is further configured to receive a fourth address of the PDU session from a second session management function network element;

the processing unit is further configured to allocate, to the remote UE, a port number used for transmitting data of the first service on the fourth address.

20. The communications device of claim 19, wherein the communications unit is further configured to:

and sending the identification information of the remote UE, the fourth address and the port number to the second session management function network element, or sending the identification information of the remote UE, the identification information of the PDU session and the port number.

21. A communication apparatus comprising at least one processor coupled to a memory, the at least one processor configured to read and execute a program stored in the memory to cause the apparatus to perform the method of any of claims 1-10.

22. A chip coupled to a memory for reading and executing program instructions stored in the memory to implement the method of any one of claims 1-10.

23. A computer-readable storage medium having stored thereon computer instructions which, when executed on a computer, cause the computer to perform the method of any one of claims 1-10.