CN110972224A

CN110972224A - Communication method, device and system

Info

Publication number: CN110972224A
Application number: CN201811154008.8A
Authority: CN
Inventors: 宗在峰; 朱奋勤
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2018-09-29
Filing date: 2018-09-29
Publication date: 2020-04-07
Anticipated expiration: 2038-09-29
Also published as: CN110972224B

Abstract

The embodiment of the application provides a communication method, a communication device and a communication system, which can ensure service continuity when a terminal is switched across systems. The method comprises the following steps: the target mobile management network element determines a session to be recovered, wherein the session to be recovered is a session needing to allocate wireless resources in a second network, the session to be recovered is established through a first network, but the first network does not allocate the wireless resources to the session to be recovered; and the target mobile management network element allocates the radio resource of the second network for the bearing of the session to be recovered.

Description

Communication method, device and system

Technical Field

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

Background

With the rapid development of wireless communication technology, a fifth generation (5th-generation, 5G) mobile network is in operation, and the 5G network can coexist with the existing fourth generation (4th-generation, 4G) mobile network, and the two networks are communicated with each other.

In the 5G network, Selective Protocol Data Unit (PDU) Session (Selective PDU Session activation) is supported, that is, an N3 tunnel is selectively established for the PDU Session and radio resources are allocated. Based on this, when the terminal is in the connected state, only part of the PDU sessions needed to be used may be activated, and the other N3 tunnels of the PDU sessions that are not needed to be used temporarily may be inactivated temporarily. These inactive PDU sessions may be subsequently activated by a Session Management Function (SMF) network element or terminal as required.

In a scenario of interworking between a 5G network and a 4G network, when a terminal switches from the 5G network to the 4G network, the terminal needs to switch from a PDU session in the 5G network to a Packet Data Network (PDN) connection of the 4G network, and a base station of the 4G network allocates a radio resource of the 4G network to the PDN connection. When the terminal is switched from the 5G network to the 4G network, the base station of the 5G network transmits the transparent container to the base station of the 4G network, and the base station of the 4G network allocates the wireless resources of the 4G network for the PDN connection corresponding to the PDU session according to the information in the transparent container transmitted by the base station of the 5G network.

However, since the base station of the 5G network does not store any information of the PDU session in the inactive state, the base station of the 5G network does not include any information of the PDU session in the inactive state in the transparent container sent to the 4G base station, which results in that the base station of the 4G network does not allocate any radio resource for the PDN connection corresponding to the PDU session in the inactive state.

Since selective session activation is not supported in 4G, a Mobility Management Entity (MME) may release sessions to which no radio resource is allocated, so when a terminal is switched from a 5G network to a 4G network, according to the existing procedure, a PDU session in an inactive state is released, and the release of a session may cause that the terminal cannot find a corresponding session when application-related data needs to be sent, resulting in service interruption.

Disclosure of Invention

The embodiment of the application provides a communication method, a communication device and a communication system, which ensure service continuity when a terminal is switched across systems.

In order to achieve the above purpose, the embodiment of the present application adopts the following technical solutions:

in a first aspect, a communication method is provided, and after a terminal is handed over from a first network to a second network, the method may include: the target mobile management network element determines a session to be recovered, wherein the session to be recovered is a session needing to allocate radio resources in a second network, the session to be recovered is established through a first network, and the first network does not allocate the radio resources to the session to be recovered; the target mobility management allocates radio resources of the second network for the bearer of the session to be resumed.

By the communication method provided by the embodiment of the application, the target mobile network element determines the session to be recovered without the radio resource allocation, and allocates the radio resource of the second network for the bearer of the session to be recovered, so as to avoid the second network releasing the session. Therefore, after the terminal is switched from the first network to the second network across the system, if the data of the applications carried on the sessions are sent in the second network, the target mobile network element allocates radio resources to the sessions, so that the data related to the applications can still be sent by using the sessions, the user plane corresponding to the sessions is used as a transmission channel of the data of the service, and the terminal uses the same session before and after switching the network, thereby ensuring the service continuity.

Optionally, the radio resource may be an air interface resource between the terminal and the base station; alternatively, the radio resource may be a tunnel between the base station and the core network; alternatively, the radio resource may be an air interface resource between the terminal and the base station and a tunnel between the base station and the core network. The present application is not limited to the specific content of the radio resource.

The target mobility management network element refers to a network element for performing mobility management in a second network which is used as a terminal for cross-system handover. The mobility management element may have different names in different systems, and is not limited herein.

In a possible implementation manner, the determining, by the target mobility management network element, a session to be resumed may specifically be implemented as: a target mobile management network element receives a Tracking Area Update (TAU) request from a terminal, wherein the TAU request carries first indication information; and the target mobile management network element determines the session to be recovered according to the first indication information. Because the session information is stored in the terminal, the terminal can determine the session to be restored according to the session information, and transmit the session restoration information to the target mobility management network element by carrying the first indication information in the TAU information, so that the target mobility management network element determines the session to be restored according to the first indication information.

In a possible implementation manner, when receiving a first TAU request from a terminal after a handover from a first network to a second network, a target mobility management network element determines a session to be resumed according to first indication information carried in the TAU request. Due to a plurality of sending scenes of the TAU request, a first indication information for indicating the session to be recovered is carried in a first TAU request sent by the terminal after the terminal is switched from the first network to the second network, and the target mobility management network element determines the session to be recovered when receiving the first TAU request from the terminal after the terminal is switched from the first network to the second network.

In a possible implementation manner, the first indication information may be an access point name corresponding to the session to be resumed.

In a possible implementation manner, when the first indication information is an access point name corresponding to the session to be recovered, the access point name corresponding to the session to be recovered may be directly carried in the TAU request.

In a possible implementation manner, when the first indication information is an access point name corresponding to the session to be recovered, the access point name corresponding to the session to be recovered may be carried in a session (NAS) container, and then the NAS container of the session is carried in the TAU request. Illustratively, the session NAS container may be a session establishment request.

Further optionally, when the access point name corresponding to the session to be recovered is carried in the session NAS container and sent, the session NAS container may further include a Protocol Configuration Option (PCO), where the PCO includes a session identifier of the session to be recovered in the first network.

In a possible implementation manner, the target mobility management element allocates a radio resource of the second network to a bearer of the session to be resumed, which may specifically be implemented as: the target mobile management network element acquires the identification of the control plane function network element corresponding to the session to be recovered from the context corresponding to the session to be recovered in the second network; the target mobile management network element sends a request message to the control plane function network element; the target mobile management network element receives the bearing information of the session to be recovered from the control plane function network element; and the target mobile management network element requests the access equipment of the second network to allocate the radio resources of the second network for the bearer of the session to be recovered. In this implementation, the target mobility management network element requests the control plane function network element to reestablish the session to be restored via the second network, and allocates radio resources of the second network to the bearer of the reestablished session to be restored during the establishment process.

Illustratively, the bearer information may be quality of service (QoS) information for QoS flows.

Further optionally, the target mobility management network element allocates a bearer identifier for the session to be recovered, and sends the bearer identifier to the control plane function network element and the terminal.

Further optionally, after the target mobility management element requests the control plane function element to reestablish the session to be restored through the second network, the session to be restored that has been established through the first network may be deleted. The specific deletion process is not described in detail.

In a possible implementation manner, the first indication information may be a bearer state of the session to be resumed. The bearer state of the session to be recovered may be a preset state. Correspondingly, the target mobility management network element determines the session to be restored according to the first indication information, which may specifically be: and the target mobile management network element determines the session of which the bearing state is a preset state and which is not allocated with the wireless resource as the session to be recovered. The terminal sets the determined bearing state of the session to be recovered to a preset state so as to indicate the target mobile management network element to allocate the radio resource of the second network to the target mobile management network element. Since the terminal may also set the bearers of sessions other than the session to be recovered to the preset state for other reasons, the target mobility management element determines the session in which the bearers are in the preset state and radio resources are not allocated as the session to be recovered, so as to avoid misoperation.

In a possible implementation manner, the terminal may be configured to set only the bearer state of the bearer of the session to be recovered, which is determined by the terminal, to a preset state, and correspondingly, the target mobility management network element determines the session to be recovered according to the first indication information, which specifically may be: and the target mobile management network element determines the session with the bearing state as a preset state as the session to be recovered.

In one possible implementation, the preset state may be Active (Active). Of course, the content of the preset state may also be configured according to actual requirements, which is not limited in this application.

In a possible implementation manner, when the first indication information is a bearer state of the session to be resumed, the bearer state may be represented by bearer state indication information.

In a possible implementation manner, the determining, by the target mobility management network element, a session to be restored may specifically be implemented as: and the target mobile management network element determines a part of session or all session which is not allocated with radio resources and the bearer of which is not included in the session of the radio bearer list failed to be established as the session to be recovered. Because the session which is not activated in the first network has the characteristics of not allocating resources in the first network and not triggering the establishment of the bearer for the terminal in the process of switching from the first network to the second network, the target mobility management network element firstly determines the session which is not activated in the first network, selects part of or all of the session from the session which is not activated in the first network as the session to be recovered, and allocates resources of the second network for the bearer of the session to be recovered, so that the session to be recovered is successfully switched from the first network to the second network.

In a possible implementation manner, the communication method provided by the present application may further include: the target mobility management network element receives a second indication from the source mobility management network element, wherein the second indication is used for indicating an inactive session in the first network; correspondingly, the target mobility management network element determines the session to be restored, which may specifically be implemented as: and the target mobile management network element determines part of or all of the sessions which are not activated in the first network as the sessions to be recovered according to the second indication. And the target mobile management network element firstly determines the inactivated sessions in the first network according to the second indication, selects partial sessions or all sessions from the inactivated sessions in the first network as sessions to be recovered, and allocates resources of the second network for the bearers of the sessions to be recovered, so that the sessions to be recovered are successfully switched from the first network to the second network.

In one possible implementation, the second indication may be included in a context in which the session to be resumed corresponds in the second network.

In a possible implementation manner, the target mobility management network element selects a part of or all of the sessions from the inactive sessions in the first network as the sessions to be resumed according to a preset policy.

In a possible implementation manner, the presetting policy may include taking a session carrying the preset service as a session to be restored, and accordingly, the target mobility management network element takes a session carrying the preset service and being inactive in the first network as a session to be restored.

In a possible implementation manner, the preset policy may include taking a session that carries the preset service and is not activated in the first network as a session to be recovered, and correspondingly, the target mobility management network element takes the session that carries the preset service and is not activated in the first network as the session to be recovered according to the preset policy.

In a possible implementation manner, the target mobility management element allocates a radio resource of the second network to a bearer of the session to be resumed, which may specifically be implemented as: and the target mobile management network element sends a bearer creating request to the access equipment of the second network according to the bearer context of the session to be recovered in the context corresponding to the second network, wherein the bearer creating request is used for allocating the radio resources of the second network to the bearer of the session to be recovered.

In a possible implementation manner, the communication method provided by the present application may further include: and the target mobile management network element acquires the context of the session to be recovered in the second network.

The target mobility management network element may obtain, from a source mobility management network element in the first network, a context corresponding to the session to which the radio bearer identifier is assigned in the second network in a process in which the terminal is handed over from the first network to the second network.

For example, the radio bearer Identity may be an evolved packet domain system bearer Identity (EBI).

In a second aspect, a communication method is provided, and after a terminal is handed over from a first network to a second network, the method may include: the terminal determines a session to be recovered, wherein the session to be recovered is a session needing to allocate wireless resources in a second network, the session to be recovered is established through a first network, but the first network does not allocate the wireless resources to the session to be recovered; the terminal sends a TAU request to a target mobile management network element, wherein the TAU request carries first indication information, and the first indication information is used for indicating information of a session to be recovered.

According to the communication method provided by the embodiment of the application, the terminal determines the session to be recovered without the wireless resource allocation, and notifies the target mobility management network element of the session to be recovered, so that the target mobility management network element determines the session to be recovered and allocates the wireless resource of the second network for the bearer of the session to be recovered, and the second network is prevented from releasing the session. Therefore, after the terminal is switched from the first network to the second network across the system, if the data of the applications carried on the sessions are sent in the second network, the target mobile network element allocates radio resources to the sessions, so that the data related to the applications can still be sent by using the sessions, the user plane corresponding to the sessions is used as a transmission channel of the data of the service, and the terminal uses the same session before and after switching the network, thereby ensuring the service continuity.

In a possible implementation manner, the determining, by the terminal, the session to be resumed may specifically be implemented as: and the terminal determines part of or all of the inactivated sessions which are allocated with the radio bearer identifications as the sessions to be recovered. The session with the allocated radio bearer identity is a session supporting handover to a second network, the session supporting handover to the second network includes an active session and an inactive session, and in the process of handover of the terminal from the first network to the second network, radio resources of the second network are already allocated to the bearer of the active session, but radio resources of the second network are not allocated to the bearer of the inactive session, so that part of or all of the sessions are selected as sessions to be recovered, and radio resources of the second network are allocated to the sessions through the scheme provided by the application.

In a possible implementation manner, the determining, by the terminal, the session to be resumed may specifically be implemented as: and the terminal selects a part of or all the sessions from the inactive sessions which are allocated with the radio bearer identifications as the sessions to be recovered according to a preset strategy. The session with the allocated radio bearer identity is a session supporting handover to a second network, the session supporting handover to the second network includes an active session and an inactive session, and in the process of handover of the terminal from the first network to the second network, radio resources of the second network are already allocated to the bearer of the active session, but radio resources of the second network are not allocated to the bearer of the inactive session, so that part of or all of the sessions are selected according to a preset policy as sessions to be resumed, and radio resources of the second network are allocated to the sessions through the scheme provided by the application.

In a possible implementation manner, the preset policy may include a session carrying a preset service as the session to be recovered, and correspondingly, the terminal takes the session carrying the preset service and assigned with the radio bearer identifier as the session to be recovered.

In a possible implementation manner, the presetting policy may include taking a session carrying the preset service and assigned with the radio bearer identifier as a session to be restored, and correspondingly, the terminal takes the session carrying the preset service and assigned with the radio bearer identifier as the session to be restored according to the preset policy.

In a possible implementation manner, the first indication information may be an access point name corresponding to the session to be recovered; alternatively, the first indication information may be a bearer status of the session to be resumed.

It should be noted that, the first indication information has been described in detail in the foregoing first aspect, and reference may be made to the foregoing description, which is not repeated herein.

In a third aspect, a session activation method is provided, which may include: the mobility management network element determines a session to be activated, wherein the session to be activated comprises a part of session or all session in the session to which the radio bearer identification is allocated; and the mobility management network element sends an activation request to a control plane function network element corresponding to the session to be activated, wherein the activation request comprises a session identifier of the session to be activated. The activation request is used to activate the session to be activated.

According to the session activation method provided by the embodiment of the application, the mobility management network element determines whether the session can be switched to the second network (that is, cross-system switching is supported) according to whether the radio bearer identifier is allocated to the session, and the mobility management network element uses part of or all of the session supporting the cross-system switching as the session to be activated and requests activation, so that the target access network can receive bearer information of the session from the source target access network in the cross-system switching process of the terminal, thereby allocating radio resources to the bearer of the session in the target network, avoiding service interruption caused by session release by the target network due to non-activation, enabling data of services before and after network switching of the terminal to be sent by using the same session, and ensuring continuity of the terminal services in the cross-system switching.

In a possible implementation manner, the determining, by the mobility management element, a session to be activated may specifically be implemented as: and the mobile management network element selects a part of sessions or all sessions from the sessions allocated with the radio bearer identifications as sessions to be activated according to a preset strategy.

Optionally, the radio bearer identity may comprise an EBI.

In a possible implementation manner, the preset policy may include taking a session carrying a preset service as a session to be activated, and correspondingly, the mobility management element takes a session carrying a preset service and assigned with a radio bearer identifier as a session to be activated.

In a possible implementation manner, the preset policy may include taking a session carrying the preset service and assigned with the radio bearer identifier as a session to be activated, and correspondingly, the mobility management element takes the session carrying the preset service and assigned with the radio bearer identifier as the session to be activated according to the preset policy.

In a possible implementation manner, the session activation method provided by the present application may further include: the mobile management network element receives indication information from a control plane function network element, wherein the indication information is used for indicating a session needing to be permanently online; correspondingly, the determining, by the mobility management element, of the session to be activated may specifically be implemented as: and the mobile management network element determines the session needing to be permanently online as the session to be activated in the session allocated with the radio bearer identifier.

In a possible implementation manner, the session activation method provided by the present application may further include: the mobile management network element receives a service request sent from the terminal when the terminal enters the connected state from the idle state, wherein the service request may include an identifier of a session which needs to be activated and is determined by the terminal. Correspondingly, the determining, by the mobility management element, of the session to be activated may specifically be implemented as: the mobile management network element selects part of or all of the sessions in the session which is allocated with the radio bearer identifier and is not the session indicated by the identifier of the session which needs to be activated and is included in the service request, and then determines the selected session and the session indicated by the identifier of the session which needs to be activated and is included in the service request as the session to be activated.

In a possible implementation manner, the mobility management element determines a session to be activated according to the method in a process that the terminal enters a connected state from an idle state.

In a fourth aspect, a session activation method is provided, which may include: the terminal determines a session to be activated, wherein the session to be activated comprises a part of session or all session in the session distributed with the radio bearer identifier; and under the condition that the terminal enters a connection state from an idle state, the terminal sends a service request to a mobile management network element, wherein the service request comprises a session identifier of a session to be activated, and the service request is used for requesting to activate the session to be activated.

According to the session activation method provided by the embodiment of the application, under the condition that the terminal enters the connection state from the idle state, the terminal determines whether the session can be switched to the second network (namely, the cross-system switching is supported) according to whether the radio bearer identifier is allocated to the session, the terminal takes part or all of the session in the session supporting the cross-system switching as the session to be activated and requests to be activated, so that in the process of the cross-system switching of the terminal, the target access network can receive the bearer information of the session from the source target access network, and therefore radio resources are allocated to the bearer of the session in the target network, service interruption caused by the fact that the target network releases the session due to non-activation is avoided, data of services before and after the terminal switches the network are sent by using the same session, and continuity of the terminal services during the cross-system switching is guaranteed.

In a possible implementation, the terminal determines the session to be activated, which may specifically be implemented as: and the terminal determines part of or all of the sessions allocated with the radio bearer identifications as sessions to be activated according to a preset strategy.

In a possible implementation, the preset policy may include taking a session carrying a preset service as a session to be activated, and correspondingly, the terminal takes a session carrying the preset service and assigned with a radio bearer identifier as a session to be activated.

In a possible implementation manner, the presetting policy may include taking a session carrying the preset service and assigned with the radio bearer identifier as a session to be activated, and correspondingly, the terminal takes the session carrying the preset service and assigned with the radio bearer identifier as the session to be activated according to the preset policy.

In a possible implementation, the terminal receives indication information from the control plane function network element, where the indication information is used to indicate a session that needs to be permanently online; correspondingly, the terminal determines the session to be activated, which may specifically be implemented as: and the terminal determines the session needing to be permanently online as the session to be activated in the session allocated with the radio bearer identifier.

In a fifth aspect, a mobility management network element is provided, where the mobility management network element has a function of implementing the target mobility management network element in the communication method according to the first aspect. The function can be realized by hardware, and can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the functions described above.

In a sixth aspect, a mobility management element is provided, comprising: a processor and a memory; the memory is configured to store computer executable instructions, and when the mobility management element is running, the processor executes the computer executable instructions stored by the memory to cause the mobility management element to perform the communication method according to any of the above first aspects.

A seventh aspect provides a mobility management element, including: a processor; the processor is configured to be coupled to the memory, and after reading the instructions in the memory, execute the communication method according to any one of the above first aspects according to the instructions.

In an eighth aspect, a computer-readable storage medium is provided, which has instructions stored therein, and when the computer-readable storage medium runs on a computer, the computer is enabled to execute the communication method of any one of the first aspect.

In a ninth aspect, there is provided a computer program product containing instructions which, when run on a computer, cause the computer to perform the communication method of any of the first aspects above.

In a tenth aspect, an apparatus (e.g., the apparatus may be a system-on-chip) is provided, which includes a processor configured to enable the apparatus to implement the functions referred to in the first aspect, such as determining a session to be resumed, and allocating radio resources of a second network for a bearer of the session to be resumed. In one possible design, the apparatus further includes a memory for storing necessary program instructions and data for the apparatus. When the device is a chip system, the device may be composed of a chip, or may include a chip and other discrete devices.

For technical effects brought by any one of the design manners in the fifth aspect to the tenth aspect, reference may be made to technical effects brought by different design manners in the first aspect, and details are not described herein.

In an eleventh aspect, a terminal is provided, which has the function of implementing the terminal in the communication method according to the second aspect. The function can be realized by hardware, and can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the functions described above.

In a twelfth aspect, a terminal is provided, including: a processor and a memory; the memory is used for storing computer executable instructions, and when the terminal runs, the processor executes the computer executable instructions stored in the memory, so that the terminal executes the communication method according to any one of the second aspect.

In a thirteenth aspect, a terminal is provided, including: a processor; the processor is configured to be coupled with the memory, and after reading the instruction in the memory, execute the communication method according to any one of the second aspect.

In a fourteenth aspect, a computer-readable storage medium is provided, which has instructions stored therein, which when run on a computer, make the computer perform the communication method of any one of the above second aspects.

In a fifteenth aspect, there is provided a computer program product containing instructions which, when run on a computer, enable the computer to perform the communication method of any of the second aspects described above.

In a sixteenth aspect, an apparatus (for example, the apparatus may be a system on a chip) is provided, where the apparatus includes a processor configured to enable the apparatus to implement the functions referred to in the second aspect, for example, determine a session to be resumed, and send a tracking area update TAU request to a target mobility management network element, where the TAU request carries first indication information, and the first indication information is used to indicate information of the session to be resumed. In one possible design, the apparatus further includes a memory for storing necessary program instructions and data for the apparatus. When the device is a chip system, the device may be composed of a chip, or may include a chip and other discrete devices.

For technical effects brought by any one of the design manners in the eleventh aspect to the sixteenth aspect, reference may be made to technical effects brought by different design manners in the second aspect, and details are not repeated here.

A seventeenth aspect provides a mobility management element having a function of implementing the mobility management element in the session activation method according to the third aspect. The function can be realized by hardware, and can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the functions described above.

In an eighteenth aspect, there is provided a mobility management network element, comprising: a processor and a memory; the memory is configured to store computer executable instructions, and when the mobility management element is running, the processor executes the computer executable instructions stored by the memory to cause the mobility management element to perform the communication method according to any of the third aspect.

In a nineteenth aspect, there is provided a mobility management network element, comprising: a processor; the processor is configured to couple with the memory, and after reading the instruction in the memory, execute the session activation method according to any one of the third aspects.

In a twentieth aspect, a computer-readable storage medium is provided, having stored therein instructions, which, when run on a computer, cause the computer to perform the session activation method of any one of the above third aspects.

In a twenty-first aspect, there is provided a computer program product containing instructions which, when run on a computer, cause the computer to perform the session activation method of any one of the above-mentioned third aspects.

In a twenty-second aspect, an apparatus (for example, the apparatus may be a system-on-chip) is provided, which includes a processor configured to enable the apparatus to implement the functions involved in the third aspect, for example, determine a to-be-activated session, where the to-be-activated session includes a part of or all of sessions assigned with radio bearer identities; and sending an activation request to a control plane function network element corresponding to the session to be activated, wherein the activation request comprises a session identifier of the session to be activated. In one possible design, the apparatus further includes a memory for storing necessary program instructions and data for the apparatus. When the device is a chip system, the device may be composed of a chip, or may include a chip and other discrete devices.

For technical effects brought by any one of the design manners in the seventeenth aspect to the twenty-second aspect, reference may be made to technical effects brought by different design manners in the third aspect, and details are not described here.

A twenty-third aspect provides a terminal having a function of implementing the terminal in the session activation method described in the fourth aspect. The function can be realized by hardware, and can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the functions described above.

In a twenty-fourth aspect, there is provided a terminal comprising: a processor and a memory; the memory is configured to store computer executable instructions, and when the terminal runs, the processor executes the computer executable instructions stored in the memory, so as to enable the terminal to execute the session activation method according to any one of the above fourth aspects.

In a twenty-fifth aspect, a terminal is provided, comprising: a processor; the processor is configured to be coupled with the memory, and after reading the instruction in the memory, execute the session activation method according to any one of the above fourth aspects according to the instruction.

A twenty-sixth aspect provides a computer-readable storage medium having stored therein instructions which, when run on a computer, cause the computer to perform the session activation method of any one of the above-mentioned fourth aspects.

A twenty-seventh aspect provides a computer program product comprising instructions which, when run on a computer, cause the computer to perform the method of a conversation as described in any of the fourth aspects above.

In a twenty-eighth aspect, an apparatus (e.g., the apparatus may be a system-on-chip) is provided, which includes a processor configured to enable the apparatus to implement the functions recited in the fourth aspect, such as determining a to-be-activated session, where the to-be-activated session includes a part of or all of a session to which a radio bearer identity is assigned; and sending a service request to a mobile management network element under the condition that a terminal to which the device belongs enters a connected state from an idle state, wherein the service request comprises a session identifier of a session to be activated, and the service request is used for requesting to activate the session to be activated. In one possible design, the apparatus further includes a memory for storing necessary program instructions and data for the apparatus. When the device is a chip system, the device may be composed of a chip, or may include a chip and other discrete devices.

The technical effects brought by any one of the design manners in the twenty-third aspect to the twenty-eighth aspect can be referred to the technical effects brought by different design manners in the fourth aspect, and are not described herein again.

In a twenty-ninth aspect, there is provided a communication system comprising: a mobility management network element and a terminal. The mobile management network element is used for determining a session to be recovered after the terminal is switched from the first network to the second network; the session to be recovered is a session needing to allocate wireless resources in the second network, the session to be recovered is established through the first network, but the first network does not allocate the wireless resources for the session to be recovered; the mobility management element is further configured to allocate radio resources of the second network for the bearer of the session to be resumed.

In a possible implementation manner, a terminal is configured to determine a session to be resumed, and send a TAU request to a mobility management network element, where the TAU request carries first indication information, and the first indication information is used to indicate information of the session to be resumed; correspondingly, the determining, by the mobility management network element, the session to be restored specifically includes: and determining the session to be recovered according to the first indication information.

The technical effects brought by any one of the twenty-ninth aspects can be referred to the technical effects brought by the different design manners in the first aspect or the second aspect, and are not described herein again.

In a thirtieth aspect, there is provided a session activation system, the system comprising: a mobility management network element and a control plane function network element. The mobile management network element is used for determining a session to be activated, wherein the session to be activated comprises a part of session or all session in the session to which the radio bearer identifier is allocated; the mobility management network element is further configured to send an activation request to a control plane function network element corresponding to the session to be activated, where the activation request includes a session identifier of the session to be activated.

The technical effects brought by the thirtieth aspect can be referred to the technical effects brought by different design manners in the third aspect, and are not described herein again.

In a thirty-first aspect, there is provided a session activation system, comprising: a terminal, a mobile management network element and a control plane function network element. The terminal is used for determining a session to be activated, wherein the session to be activated comprises a part of session or all session in the session distributed with the radio bearer identifier; the terminal is also used for sending a service request to the mobile management network element under the condition of entering a connection state from an idle state, wherein the service request comprises a session identifier of a session to be activated, and the service request is used for requesting to activate the session to be activated; the mobility management network element is configured to send an activation request to a control plane function network element corresponding to the session to be activated, where the activation request includes a session identifier of the session to be activated.

The technical effects brought by the thirty-first aspect can be referred to the technical effects brought by different design manners in the fourth aspect, and are not described herein again.

These and other aspects of the present application will be more readily apparent from the following description of the embodiments.

Drawings

Fig. 1 is a first schematic architecture diagram of a communication system according to an embodiment of the present application;

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

fig. 3 is a schematic diagram of an existing interworking architecture between a 4G network and a 5G network;

fig. 3a is a schematic diagram of a network architecture for interworking between a 4G network and a 5G network in an LBO roaming scenario;

fig. 4 is a schematic diagram of a network architecture for interworking between a 4G network and a 5G network in a hometer roaming scenario;

fig. 5 is a schematic structural diagram of a communication device according to an embodiment of the present application;

fig. 6 is a flowchart illustrating a communication method according to an embodiment of the present application;

fig. 7 is a flowchart illustrating a session activation method according to an embodiment of the present application;

fig. 8 is a first schematic structural diagram of a mobility management element according to an embodiment of the present application;

fig. 9 is a first schematic structural diagram of a terminal according to an embodiment of the present application;

fig. 10 is a schematic structural diagram of a mobility management element according to an embodiment of the present application;

fig. 11 is a schematic structural diagram of a terminal according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application. Where in the description of the present application, "/" indicates a relationship where the objects associated before and after are an "or", unless otherwise stated, for example, a/B may indicate a or B; in the present application, "and/or" is only an association relationship describing an associated object, and means that there may be three relationships, for example, a and/or B, and may mean: a exists alone, A and B exist simultaneously, and B exists alone, wherein A and B can be singular or plural. Also, in the description of the present application, "a plurality" means two or more than two unless otherwise specified. "at least one of the following" or similar expressions refer to any combination of these items, including any combination of the singular or plural items. For example, at least one (one) of a, b, or c, may represent: a, b, c, a-b, a-c, b-c, or a-b-c, wherein a, b, c may be single or multiple. In addition, in order to facilitate clear description of technical solutions of the embodiments of the present application, in the embodiments of the present application, terms such as "first" and "second" are used to distinguish the same items or similar items having substantially the same functions and actions. Those skilled in the art will appreciate that the terms "first," "second," etc. do not denote any order or quantity, nor do the terms "first," "second," etc. denote any order or importance.

In addition, the network architecture and the service scenario described in the embodiment of the present application are for more clearly illustrating the technical solution of the embodiment of the present application, and do not constitute a limitation to the technical solution provided in the embodiment of the present application, and it can be known by a person skilled in the art that the technical solution provided in the embodiment of the present application is also applicable to similar technical problems along with the evolution of the network architecture and the appearance of a new service scenario.

As shown in fig. 1, a communication system 10 provided for the embodiment of the present application includes a target mobility management network element 101 and a terminal 102 in the communication system 10. Wherein the terminal 102 is handed over from the first network to the second network.

The target mobility management element 101 is a mobility management element in the second network. The target mobility management network element 101 is configured to determine a session to be resumed, where the session to be resumed is a session that needs to allocate radio resources in a second network, and the session to be resumed is already established by the first network, but the first network does not allocate radio resources to the session to be resumed; and allocating the radio resource of the second network for the bearing of the session to be recovered.

In a possible implementation, the target mobility management network element 101 receives a TAU request from the terminal 102, where the TAU request carries the first indication information, and the target mobility management network element 101 determines, according to the first indication information, that the session is to be resumed.

Optionally, the first indication information may include an access point name corresponding to the session to be resumed; alternatively, the first indication information may include that the bearer status of the session to be resumed is a preset status.

In one possible implementation, the target mobility management network element 101 determines that a part of or all of the sessions, which are not allocated with radio resources and whose bearers are not included in the session of the radio bearer list that is failed to be established, are to-be-recovered sessions.

In one possible implementation, the target mobility management element 101 receives a second indication from the source mobility management element, the second indication indicating an inactive session in the first network; and the target mobility management network element 101 determines a part of or all of the inactivated sessions in the first network as sessions to be recovered according to the second indication.

According to the communication system provided by the application, the target mobile network element determines the session to be recovered without the wireless resource allocation, allocates the wireless resource of the second network for the bearer of the session to be recovered, and avoids the second network releasing the session. Therefore, after the terminal is switched from the first network to the second network across the system, if the data of the applications carried on the sessions are sent in the second network, the target mobile network element allocates radio resources to the sessions, so that the data related to the applications can still be sent by using the sessions, the user plane corresponding to the sessions is used as a transmission channel of the data of the service, and the terminal uses the same session before and after switching the network, thereby ensuring the service continuity.

It should be noted that the communication method provided in the present application is applied to a scenario of terminal cross-system handover, in which an inactive session in a source network for handover is implemented, and a wireless resource is successfully allocated in a target network for handover to complete the session cross-system handover of the terminal. The description is unified here and will not be pointed out later.

The session handover means that, as the terminal is handed over from system to system, the radio resources of the target network are allocated to the session in the target network, and the control plane function network element of the session is kept unchanged.

As shown in fig. 2, a communication system 20 provided for the embodiment of the present application includes a mobility management network element 201 and a control plane function network element 202 in the communication system 20.

In a possible implementation, the mobility management network element 201 is configured to determine a session to be activated, where the session to be activated includes a part of or all of the sessions to which the radio bearer identifier is assigned; and sending an activation request to a control plane function network element 202 corresponding to the session to be activated, where the activation request includes a session identifier of the session to be activated, and the activation request is used to activate the session to be activated.

Optionally, the mobility management element 201 may select a part of the sessions or all the sessions from the sessions assigned with the radio bearer identifier as the sessions to be activated according to a preset policy.

Further, the mobility management element 201 may be further configured to receive indication information from the control plane function element 202, where the indication information is used to indicate a session that needs to be permanently online; the determining, by the mobility management network element 201, of the session to be activated may specifically be implemented as: the mobility management element 201 determines the session to be permanently online as the session to be activated, which is indicated by the indication information in the session to which the radio bearer identifier is allocated.

In one possible implementation, the session to be activated may be determined by the terminal, where the session to be activated includes a part of the session or all of the session to which the radio bearer identity is assigned; when the terminal enters the connected state from the idle state, the terminal sends a service request to the mobility management network element 201 in the communication system illustrated in fig. 2, where the service request includes a session identifier of a session to be activated, so that the mobility management network element 201 requests a control plane function network element corresponding to the session to be activated to activate the session to be activated.

According to the communication system provided by the application, the mobile management network element determines whether the session can be switched to the second network (namely, the cross-system switching is supported) according to whether the radio bearer identifier is allocated to the session, the mobile management network element takes part or all of the session supporting the cross-system switching as the session to be activated and requests for activation, so that the target access network can receive bearer information of the session from the source target access network in the cross-system switching process of the terminal, thereby allocating radio resources to the bearer of the session in the target network, avoiding service interruption caused by the release of the session by the target network due to non-activation, enabling data of services before and after the network is switched by the terminal to be sent by using the same session, and ensuring the continuity of the terminal services during the cross-system switching.

Alternatively, the communication system shown in fig. 1 or fig. 2 may be applied to the current interworking architectures of 4G networks and 5G networks, and may be applied to other interworking architectures in the future, which is not specifically limited in this embodiment of the present application.

Fig. 3 is a schematic diagram of an existing interworking architecture between a 4G network and a 5G network. The 4G network and the 5G network share a User Plane Function (UPF) network element + a Packet Data Network (PDN) gateway user plane function (PGW-U) network element, a Session Management Function (SMF) network element + a PDN gateway control plane function (PGW-C) network element, a policy control function (policy and charging rules function, PCF) network element + a Policy and Charging Rules Function (PCRF) network element, a Home Subscriber Server (HSS) + a Unified Data Management (UDM) network element. Here, "+" indicates a convergence, where UPF is a user plane function of a 5G network, PGW-U is a gateway user plane function of a 4G network corresponding to UPF, SMF is a session management function of the 5G network, PGW-C is a gateway control plane function in the 4G network corresponding to SMF, PCF is a policy control function of the 5G network, and PCRF is a policy charging rule function of the 4G network corresponding to PCF. In the embodiment of the present application, for convenience of description, the UDM network element and the HSS are referred to as a user data management network element, the SMF network element and the PGW-C network element are referred to as a control plane function network element, and the UPF network element and the PGW-U network element are referred to as a user plane function network element, which are described in a unified manner and will not be described below. Of course, the combined network device may also use other names, and this embodiment of the present application is not limited to this specifically.

In addition, as shown in fig. 3, the interworking architecture between the 4G network and the 5G network may further include an MME and a Serving Gateway (SGW) in the 4G network, and an access and mobility management function (AMF) network element in the 5G network. Optionally, the interworking architecture between the 4G network and the 5G network may further include a network handover selection function (NSSF) network element. When the AMF network element cannot select a network slice for the terminal, the AMF network element may request the NSSF network element to select a network slice for the terminal, which is not specifically limited in this embodiment of the present application.

In the interworking architecture between the 4G network and the 5G network illustrated in fig. 3, the terminal accesses the 4G network through evolved universal terrestrial radio access network (E-UTRAN) equipment, and the terminal accesses the 5G network through next generation radio access network (NG-RAN) equipment. The E-UTRAN device communicates with the MME through an S1-MME interface, the E-UTRAN device communicates with the SGW through an S1-U interface, the MME communicates with the SGW through an S11 interface, the MME communicates with the user data management network element through an S6a interface, the MME communicates with the AMF network element through an N26 interface, the SGW communicates with a UPF network element + PGW-U network element through an S5-U interface, the SGW communicates with the SMF network element + PGW-C network element through an S5-C interface, the UPF network element + PGW-U communicates with the UPF network element + PGW-RAN device through an N3 interface, the UPF network element + PGW-U network element communicates with the SMF network element + PGW-C network element through an N4 interface, the SMF network element + PGW-C network element communicates with the PCF network element + PCF network element through an N7 interface, the UDM network element + HSS communicates with the SMF network element + PGW-C network element through an N10 interface, the UDM network element + HS, the PCF network element and the PCRF network element are communicated with the AMF network element through an N15 interface, the SMF network element and the PGW-C network element are communicated with the AMF network element through an N11 interface, the AMF network element is communicated with the NG-RAN equipment through an N2 interface, and the AMF network element is communicated with the terminal through an N1 interface.

It should be noted that the interface name between each network element in fig. 3 is only an example, and the interface name may be other names in a specific implementation, which is not specifically limited in this embodiment of the present application.

It should be noted that E-UTRAN devices in a 4G network and NG-RAN devices in a 5G network may also be referred to as access devices, and the access devices refer to devices accessing a core network, and may be, for example, a base station, a broadband network service gateway (BNG), a convergence switch, a non-3 GPP access device, and the like. The base stations may include various forms of base stations, such as: macro base stations, micro base stations (also referred to as small stations), relay stations, access points, and the like, which are not specifically limited in this embodiment of the present application. The device for the terminal to access the core network is collectively referred to as an access device in the text, and will not be described again.

Certainly, other network elements may also be in the 4G network and the 5G network, for example, the 4G network may further include a General Packet Radio System (GPRS) service support node (SGSN) and the like, and the 5G network may further include an authentication service function (AUSF) network element and the like, which is not specifically limited in this embodiment of the present application.

Due to the mobility of the terminal device, when the terminal moves in the framework of interworking between the 4G network and the 5G network, the terminal may be in a Local Breakout (LBO) roaming scenario or a home routed (home routed) roaming scenario, where the LBO roaming may refer to a roaming user accessing a network through a gateway of a visited network to obtain a corresponding service, and a service provider may be a Home Public Land Mobile Network (HPLMN) or a Visited Public Land Mobile Network (VPLMN). For example, as shown in fig. 3a, in the framework of interworking between a 4G network and a 5G network in a roaming scenario, a terminal accesses a network through an SMF entity and a PGW-C entity in a VPLMN to obtain a corresponding service, and user plane traffic of all the accessed services is forwarded to an h-PCF entity and an h-PCRF entity in the HPLMN through the v-PCF entity and the v-PCF entity in the VPLMN, that is, the SMF entity and the PGW-C entity are located at a visited place under local breakout roaming, and functions thereof are not changed, which is not described herein again. home routed roaming refers to that a v-SMF entity of a visited place is connected with a home SMF entity + PGW-C entity through a home routing to perform control signaling transmission, and the home UPF entity + PGW-U entity is connected with a data network, such as: fig. 4 shows a network system architecture for interworking between 4G network and 5G network in a home routed roaming scenario, where the v-SMF entity is a visited SMF entity, and the v-PCF entity is a visited PCF entity, and functions thereof are not changed, which is not described herein again.

For example, if the communication system 10 shown in fig. 1 is applied to the interworking architecture between the 4G network and the 5G network illustrated in fig. 2 or fig. 3a or fig. 4, when the terminal 102 is handed over from the 5G network to the 4G network, the target mobility management network element 101 may be the MME illustrated in fig. 2 or fig. 3a or fig. 4.

For example, if the communication system 20 shown in fig. 2 is applied to the interworking architecture between the 4G network and the 5G network illustrated in fig. 3 or fig. 3a or fig. 4, when the terminal is handed over from the 5G network to the 4G network, the mobility management network element 201 may be the AMF illustrated in fig. 3 or fig. 3a or fig. 4, and the control plane function network element 202 may be the PGW-C + SMF illustrated in fig. 3 or fig. 3a or fig. 4.

It should be noted that the names of the interfaces between the network elements in the figures are only an example, and the names of the network elements or the names of the interfaces in the specific implementation may be other names, which is not specifically limited in this embodiment of the present application.

Optionally, the terminal (terminal) referred to in the embodiments of the present application may include various handheld devices with wireless communication functions, vehicle-mounted devices, wearable devices, computing devices, or other processing devices connected to a wireless modem; a subscriber unit (subscriber unit), a cellular phone (cellular phone), a smart phone (smart phone), a wireless data card, a Personal Digital Assistant (PDA) computer, a tablet computer, a wireless modem (modem), a handheld device (dhhand), a laptop computer (laptop), a cordless phone (cordless phone) or a Wireless Local Loop (WLL) station, a Machine Type Communication (MTC) terminal, a User Equipment (UE), a Mobile Station (MS), a terminal equipment (terminal device) or a relay user equipment, etc. may also be included. The relay user equipment may be, for example, a 5G home gateway (RG). For convenience of description, the above-mentioned devices are collectively referred to as a terminal in this application.

Optionally, the access device referred to in this embodiment of the present application refers to a device accessing a core network, and may be, for example, a base station, a broadband network service gateway (BNG), a convergence switch, a non-third generation partnership project (3rd generation partnership project, 3GPP) access device, and the like. The base stations may include various forms of base stations, such as: macro base stations, micro base stations (also referred to as small stations), relay stations, access points, etc.

Optionally, in this embodiment of the present application, the target mobility management network element or the terminal in fig. 1, or the mobility management network element or the terminal in fig. 2 may be implemented by one device, or may be implemented by multiple devices together, or may be one functional module in one device, or may also be a chip in one device, which is not specifically limited in this embodiment of the present application. It is understood that the above functions may be either network elements in a hardware device, software functions running on dedicated hardware, or virtualized functions instantiated on a platform (e.g., a cloud platform).

For example, the target mobility management element or terminal in fig. 1 or the mobility management element or terminal in fig. 2 in the embodiment of the present application may be implemented by the communication device in fig. 5. Fig. 5 is a schematic diagram illustrating a hardware structure of a communication device according to an embodiment of the present disclosure. The communication device 50 includes a processor 501, a communication line 502, a memory 503, and at least one communication interface (fig. 5 is only exemplary and includes a communication interface 504 for illustration).

The processor 501 may be a general-purpose Central Processing Unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more ics for controlling the execution of programs in accordance with the present disclosure.

The communication link 502 may include a path for transmitting information between the aforementioned components.

The communication interface 504 may be any device, such as a transceiver, for communicating with other devices or communication networks, such as an ethernet, a Radio Access Network (RAN), a Wireless Local Area Network (WLAN), etc.

The memory 503 may be, but is not limited to, a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a Random Access Memory (RAM) or other type of dynamic storage device that can store information and instructions, an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disk storage, optical disk storage (including compact disc, laser disc, optical disc, digital versatile disc, blu-ray disc, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. The memory may be separate and coupled to the processor via a communication line 502. The memory may also be integral to the processor.

The memory 503 is used for storing computer-executable instructions for executing the present application, and is controlled by the processor 501 to execute. The processor 501 is configured to execute computer-executable instructions stored in the memory 503, so as to implement the communication method or the session activation method provided by the following embodiments of the present application.

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

In particular implementations, processor 501 may include one or more CPUs such as CPU0 and CPU1 in fig. 5 as an example.

In particular implementations, communication device 50 may include multiple processors, such as processor 501 and processor 508 in fig. 5, for example, as an example. Each of these processors may be a single-core (single-CPU) processor or a multi-core (multi-CPU) processor. A processor herein may refer to one or more devices, circuits, and/or processing cores for processing data (e.g., computer program instructions).

In one implementation, the communication apparatus 50 may further include an output device 505 and an input device 506. An output device 505, which is in communication with the processor 501, may display information in a variety of ways. For example, the output device 505 may be a Liquid Crystal Display (LCD), a Light Emitting Diode (LED) display device, a Cathode Ray Tube (CRT) display device, a projector (projector), or the like. The input device 506 is in communication with the processor 501 and may receive user input in a variety of ways. For example, the input device 506 may be a mouse, a keyboard, a touch screen device, or a sensing device, among others.

The communication device 50 may be a general-purpose device or a special-purpose device. In a specific implementation, the communication device 50 may be a desktop computer, a portable computer, a web server, a Personal Digital Assistant (PDA), a mobile phone, a tablet computer, a wireless terminal device, an embedded device, or a device with a similar structure as in fig. 5. The embodiment of the present application does not limit the type of the communication device 50.

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

It should be noted that, in the following embodiments of the present application, names of messages between network elements or names of parameters in messages are only an example, and other names may also be used in a specific implementation, which is not specifically limited in this embodiment of the present application.

In one aspect, an embodiment of the present application provides a communication method. Taking the communication system shown in fig. 1 as an interworking architecture between a 4G network and a 5G network shown in fig. 3 or fig. 3a or fig. 4, when a terminal is switched from the 5G network to the 4G network, the first network is the 5G network, the second network is the 4G network, and the target mobility management network element is an MME, the communication method provided in the present application is described in detail. In the interworking architecture between the 4G network and the 5G network, the session is referred to as a PDU session in the 5G network, and referred to as a PDN connection corresponding to the PDU session in the 4G network. It can be understood that, in the embodiment of the present application, the solution of the present application is described by taking an interworking architecture of a 4G network and a 5G network as an example, and an application scenario of the solution of the present application is not specifically limited. In the following description of the embodiments, the 4G network and the second network may be replaced with each other, the 5G network and the first network may be replaced with each other, the MME and the target mobility management network element may be replaced with each other, the PDU session and the session in the first network may be replaced, and the PDN connection and the session in the second network may be replaced.

The communication method provided in the embodiment of the present application is applied to a terminal after being switched from a 5G network to a 4G network, and as shown in fig. 6, the communication method provided in the embodiment of the present application includes the following steps:

s601, the terminal sends a TAU request to the MME.

Specifically, after the terminal is switched to the 4G network, the terminal immediately sends a TAU request to the MME, so as to initiate tracking area update.

In a possible implementation, the TAU request may be a first TAU request sent by the terminal after accessing from the 4G network.

In another possible implementation, optionally, the TAU request includes first indication information, where the first indication information is used to indicate information of a session to be resumed. Based on this, as shown in fig. 6, the communication method provided in the embodiment of the present application may further include an optional step S601a before S601.

S601a, the terminal determines a session to be resumed.

The session to be recovered is a session requiring allocation of wireless resources in the 4G network, the session to be recovered is already established through the 5G network, but the 5G network does not allocate wireless resources for the session to be recovered.

Specifically, since the 5G network supports selective activation of PDU sessions such that a portion of PDU sessions are inactive, the inactive PDU sessions are established but radio resources are not allocated in the 5G network. Because the source base station in the 5G network does not store the information of the PDU session in the inactive state, in the handover of the terminal from the 5G network to the 4G network, the target base station does not allocate radio resources in the 4G network for the PDU session in the inactive state according to the existing handover procedure.

The terminal may determine that the handover procedure is from the 5G network to the 4G network according to information (e.g., air interface types) of the source base station and the target base station during the cross-system handover, and after determining that the handover procedure is from the 5G network to the 4G network, the terminal performs S601 a.

Specifically, the terminal determines that the PDU session that can be switched to 4G and is not activated is the session to be recovered. If an EBI has been allocated for a PDU session in the 5G network, the PDU session may be switched to 4G. The terminal determines whether the PDU session can be switched to 4G according to whether the PDU session is allocated with corresponding EBI; the terminal may select all or part of the PDU session as the session to be resumed from among the PDU sessions that may be switched to 4G but not activated.

In one possible implementation, the terminal selects all PDU sessions that are allocated EBI and not active as sessions to be resumed.

In another possible implementation, the terminal may select a partial session or a full session from among the inactive PDU sessions allocated with EBIs as the session to be recovered according to a preset policy.

The terminal takes the service needing to keep the continuity as the preset service, and defines the content of the preset strategy as a session for bearing the preset service as a session to be recovered; or, the preset policy may also be defined as a session corresponding to a certain Data Network Name (DNN) and/or a network slice as a session to be restored. Of course, the content of the preset policy may be configured according to actual requirements, which is not specifically limited in this embodiment of the application.

For example, the preset policy may be a local policy, or a UE routing policy (URSP) policy.

Illustratively, a local policy of a terminal configures that a session corresponding to an internet protocol multimedia subsystem (IMS) service needs to maintain continuity when performing cross-system handover, and if an APN corresponding to a PDU session to which no radio resource is allocated is the same as an APN corresponding to the IMS service, the terminal determines that the PDU session is a session to be recovered. The terminal may determine the APN corresponding to the IMS according to the policy of the URSP (for example, the APN corresponding to the IMS service is configured in the URSP). Or, the terminal may also determine whether the PDU session without the allocated radio resource is a session to be recovered according to whether a service carried by the PDU session without the allocated radio resource is a preset service, for example, if a low-latency service is currently carried on one PDU session without the allocated radio resource and the preset service is a low-latency service, the terminal takes the PDU session as the session to be recovered.

It should be noted that the above method for determining the session to be resumed by the terminal is all described as an example, and is not limited to this specifically. In actual application, the terminal can be configured according to actual requirements to determine a specific implementation scheme of the session to be recovered.

Optionally, the content of the first indication information may be configured according to actual requirements, and this is not specifically limited in this embodiment of the application. Any information that can be used to indicate a session can be referred to herein as first indication information.

In a possible implementation, the first indication information may be an Access Point Name (APN) corresponding to the session to be recovered.

Illustratively, the context of the session corresponding to the terminal stored in the terminal includes the APN of the session, so that when the APN corresponding to the session is known, the context of the session is searched according to the APN, and the session can be determined.

Optionally, when the first indication information is an APN corresponding to the session to be recovered, the APN may be carried in a session NAS container and sent, and the TAU request includes the session NAS container. Illustratively, the session NAS container may be a session establishment request.

Optionally, when the APN is carried in the session NAS container and sent, the session NAS container further includes a PCO, and the PCO includes a PDU session identifier of a session to be recovered.

In another possible implementation, the first indication information may be a bearer state of the session to be resumed. After determining the session to be resumed in S601a, the terminal sets the bearer state of the session to be resumed, which is determined by the terminal, to a preset state, and takes the bearer state as the first indication information.

The preset state may be an Active (Active) state.

Optionally, the terminal may set only the bearer state of the session to be resumed as the preset state and use the preset state as the first indication information.

Optionally, the terminal may use the bearer state indication information as the first indication information, where the bearer state indication information is used to indicate a bearer state of each session.

Illustratively, the context of the session corresponding to the terminal includes identification information of bearer(s) corresponding to the session, and the MME may search the context of the session according to the bearer identifier whose bearer state is set to the preset state, so as to determine the session.

In S601, after the terminal transmits the TAU request, the MME receives the TAU request and executes S602.

S602, the MME determines the session to be recovered.

Optionally, the specific implementation of the MME determining the session to be resumed in S602 may include, but is not limited to, the following two specific implementations (the first specific implementation and the second specific implementation).

The first implementation is as follows: and determining a session to be recovered by the terminal and informing the MME.

Corresponding to the first specific implementation, the TAU request sent by the terminal in S601 includes the first indication information, and S602 is specifically implemented as: and the MME determines the session to be recovered according to the first indication information.

In a possible implementation, the first indication information is an APN corresponding to the session to be resumed, and the MME may determine the session to be resumed according to the APN corresponding to the session to be resumed in S602.

For example, in the process of switching the terminal from the 5G network to the 4G network, the MME receives, from the AMF, a context of a PDN connection corresponding to each PDU session to which the EBI is allocated, where the context of the PDN connection includes an APN of the session, and therefore, when knowing an APN corresponding to the session, the MME searches for the context of the session according to the APN, and can determine the session.

In another possible implementation, the first indication information may be a bearer state of the session to be resumed. The context of the session corresponding to the terminal includes identification information of bearer(s) corresponding to the session.

Optionally, the terminal may set only the bearer state of the session to be resumed as the preset state and use the preset state as the first indication information. Correspondingly, the determination of the session to be resumed by the MME in S602 may specifically be implemented as: the MME can search the context of the session according to the bearer identifier of which the bearer state is set to be the preset state, namely, the session can be determined.

Optionally, the terminal may use the bearer state indication information as the first indication information, where the bearer state indication information is used to indicate a bearer state of each session. There may be other reasons for the terminal to set the state of the session to the preset state. Therefore, the determination by the MME of S602 of the session to be resumed may specifically be implemented as: the MME can search the context of the session according to the bearer identifier of which the bearer state is set to be the preset state and which is not allocated with the radio resources, namely, the session can be determined.

The MME may obtain, from a base station of the 4G network, which sessions are allocated with radio resources and which sessions are not allocated with radio resources, and determine, in combination with the bearer state, a session to be resumed.

Optionally, in a first specific implementation, the MME first determines that the TAU request from the terminal is the first TAU request sent by the terminal after accessing from the 4G network, and then performs S602.

It should be noted that, in practical applications, the TAU request may be replaced by another request message as long as the first indication information is transmitted.

The second implementation is as follows: the MME itself determines the session to resume.

In a second specific implementation, during the handover from 5G to 4G, the MME receives from the AMF the PDN connection contexts corresponding to all sessions that can be handed over to 4G, which have been allocated EBI, including sessions that are active in the 5G network and sessions that are not active in the 5G network. And the MME determines a session to be recovered according to the sessions corresponding to all the PDN connection contexts received from the AMF. Specifically, the MME determines an inactive PDU session in the 5G network, and then selects a part of or all of the sessions from the inactive PDU sessions in the 5G network as a session to be resumed.

For implementation of the MME determining an inactive PDU session in the 5G network, it can be implemented by any one of the following two schemes:

in scheme 1, the MME determines a session, which is not allocated with radio resources and whose bearer is not included in the radio bearer list failed to be established, as an inactive session.

Specifically, in scheme 1, the MME determines, according to a bearer successfully established by the base station received from the base station of the 4G network, which PDN connections the base station has not established a radio bearer for, and does not establish a radio bearer, that is, does not allocate radio resources. And, the MME receives the radio bearer list with failed establishment from the base station of the 4G network, and determines which bearers of the PDN connection are not included in the radio bearer list with failed establishment in the PDN connections where the access device does not establish the radio bearer (i.e., no radio resource is allocated), so as to determine that the PDN connections are not triggered to establish the bearers due to being not included in the transparent container sent to the 4G base station by the 5G base station, that is, the PDN connections correspond to the PDU session in the 5G network that is not activated.

In scheme 2, the MME receives a second indication from the AMF, where the second indication is used to indicate an inactive session in the 5G network, and the MME determines the inactive session according to the second indication.

Corresponding to scheme 2, as shown in fig. 6, before S602, the communication method provided in the embodiment of the present application may further include an optional step S602 a.

S602a, the AMF sends a second indication to the MME, the second indication indicating a session not activated in the 5G network.

Optionally, the AMF may send the second indication to the MME during the handover of the terminal from the 5G network to the 4G network. Of course, the AMF may also send the second instruction to the MME after the handover of the terminal from the 5G network to the 4G network is completed, which is not specifically limited in this embodiment of the application. In fig. 8, the sequence of S603a and other steps is only an example, and is not particularly limited.

For example, in the process of switching the terminal from the 5G network to the 4G network, the AMF may obtain, from an SMF + PGW-C network element (from a V-SMF in a roaming scenario), a context of a PDN connection corresponding to the PDU session to which the EBI has been allocated in the 4G network, and then send, to the MME through an N26 interface, the context of the PDN connection corresponding to the PDU session to which the EBI has been allocated in the 4G network. The second indication may be included in the context of a corresponding PDN connection in the 4G network for a PDU session for which an EBI has been allocated.

For example, the second indication may also be sent independently of the context of the PDN connection, e.g., the second indication includes session information corresponding to a session that is not activated or activated in 5G, such as a bearer identity. The MME may determine a session not activated in 5G according to the second indication.

Optionally, the SMF + PGW-C network element (V-SMF in roaming scenario) sends, to the AMF, an indication of whether the session is active when sending the PDN connection context to the AMF, and the AMF determines the second indication according to the indication of whether the session is active received from the SMF + PGW-C network element (V-SMF in roaming scenario).

After S602a, S602 may be specifically implemented as: and the MME determines the sessions which are not activated in the 5G network according to the second indication, and then selects partial sessions or all sessions from the sessions which are not activated in the 5G network as the sessions to be recovered.

It should be noted that, the above scheme for the MME to determine the inactive PDU session in the 5G network may also have other schemes, and is not specifically limited herein.

After the MME determines the inactive PDU sessions in the 5G network, the MME selects partial sessions or all sessions from the inactive PDU sessions in the determined 5G network as sessions to be recovered.

In one possible implementation, the MME selects all PDU sessions it determines that are not active in the 5G network as sessions to be resumed.

In another possible implementation, the MME may select, according to a preset policy, a partial session or a full session from the determined inactive PDU sessions in the 5G network as the session to be resumed.

The MME takes the service needing to keep the continuity as a preset service, and defines the content of the preset strategy as a session for bearing the preset service as a session to be recovered; the preset policy may also be defined as a session corresponding to a certain APN as a session to be recovered. Of course, the content of the preset policy may be configured according to actual requirements, which is not specifically limited in this embodiment of the application. For example, the preset policy may be a local policy.

It should be noted that, the MME selects a part of sessions or all sessions in the PDU session that is not activated in the 5G network as the session to be recovered according to the preset policy, and may refer to the aforementioned process in which the terminal selects the session to be recovered according to the preset policy, which is not described herein again.

It should be noted that, the above-mentioned method for the MME to determine the session to be resumed from the inactive PDU session in the 5G network is all described as an example, and is not limited to this specifically. In actual application, the MME may be configured according to actual requirements to determine a specific implementation scheme of a session to be recovered from an inactive PDU session in the 5G network.

S603, the MME allocates the wireless resources of the 4G network for the bearing of the session to be recovered.

In a possible implementation, if a TAU request message received by an MME from a terminal includes first indication information, and the first indication information is an APN, S603 is specifically implemented as: the MME acquires the identifier of a PGW-C + SMF network element corresponding to the session to be recovered from the context of the PDN connection corresponding to the 4G network; the MME sends a request message to a PGW-C + SMF network element corresponding to the session to be recovered; the MME receives the bearing information of the session to be recovered from a PGW-C + SMF network element corresponding to the session to be recovered; and the MME requests the access equipment of the 4G network to allocate the radio resources of the 4G network for the bearer of the session to be recovered.

The request message is used for requesting the PGW-C + SMF network element to reestablish the session to be restored in the 4G network and requesting the access device of the 4G network to allocate the radio resources of the 4G network for the bearer thereof in the establishment process.

Optionally, the MME allocates a default bearer identifier for the session to be resumed, and includes the default bearer identifier in the request message, so that the PGW-C + SMF network element corresponding to the session to be resumed identifies the session to be resumed. Optionally, the default bearer identifier may also be the same as the default bearer identifier in the PDN connection context corresponding to the session, which is received by the MME from the AMF in the process of switching the terminal from the 5G network to the 4G network, that is, the MME does not allocate a new default bearer identifier, which is not limited in this embodiment.

Optionally, when the first indication information is an APN corresponding to the session to be recovered, and the APN is included in the session NAS container and sent, where the session NAS container includes a PCO, and the PCO includes a PDU session identifier of the session to be recovered, the request message further includes the PDU session identifier, and the PDU session identifier is used for identifying the session to be recovered by a PGW-C + SMF network element corresponding to the session to be recovered.

In a 4G network, an MME communicates with PGW-C + SMF network elements through an SGW. In a possible implementation of S603, the specifically implementation of sending, by the MME, the request message to the PGW-C + SMF network element corresponding to the session to be resumed is: the method comprises the steps that an MME sends a session creating request to an SGW, the session creating request carries a default bearer identifier, a switching indication, an APN corresponding to a session to be recovered, a PCO in an NAS session container and an identifier of a PGW-C + SMF corresponding to the session to be recovered, the SGW sends the session creating request to the PGW-C + SMF, and the session creating request carries the APN corresponding to the session to be recovered, the default bearer identifier, the PCO and the switching indication.

After receiving the request message, the PGW-C + SMF creates a PDN connection corresponding to the session to be restored in the 4G according to the existing session establishment procedure, requests the access device of the 4G network to allocate radio resources of the 4G network to the created PDN connection, and establishes a user plane tunnel between the 4G access device and the PGW-U + UPF through the SGW. Here, the existing session establishment procedure is not described herein again.

It should be noted that, the message sent by the MME through the SGW and the PGW-C + SMF network element in the process of allocating the radio resource of the 4G network to the bearer of the session to be resumed and the content in the message are all examples, and are not limited to this specifically.

Optionally, the IP address of the PDN connection established by PGW-C + SMF in the 4G network is the same as the IP address of the PDU session in the 5G network.

In one possible implementation, S603 is specifically implemented as: and the MME sends a bearer creating request to the access equipment of the 4G network according to the bearer context of the session to be recovered in the context of the PDN connection corresponding to the 4G network, wherein the bearer creating request is used for allocating the radio resources of the second network to the bearer of the session to be recovered.

Specifically, the MME generates a request for creating a radio bearer according to a bearer context in the PDN connection context, so as to request the access device of the 4G network to allocate radio resources for a bearer of the PDN connection corresponding to the session to be resumed.

Illustratively, the MME generates a create bearer request according to the bearer context of the PDN connection, so as to allocate radio resources for the bearer of the PDN connection. After receiving the tunnel information corresponding to the bearer from the access device, the MME sends an update session request to the SGW, so as to send the tunnel information corresponding to the bearer on the access device to the SGW, thereby establishing a tunnel between the access device and the SGW for one bearer for the PDN connection. This process may be performed after the execution of the TAU procedure is finished or together with the sending of the TAU received message.

Wherein, in the process that the terminal is switched from the 5G network to the 4G network, the MME obtains, from the AMF, a context of a PDN connection corresponding to the session to be recovered in the 4G network, as shown in fig. 6, the communication method provided in the embodiment of the present application may further include an optional step S603 a.

S603a, the MME obtains, from the AMF, a context of the PDN connection corresponding to the session to be resumed in the 4G network.

For example, in the process of switching the terminal from the 5G network to the 4G network, the AMF may obtain, from an SMF + PGW-C network element (from a V-SMF in a roaming scenario), a context of a PDN connection corresponding to the PDU session to which the EBI has been allocated in the 4G network, and then send, to the MME through an N26 interface, the context of the PDN connection corresponding to the PDU session to which the EBI has been allocated in the 4G network.

It should be noted that step S603a is only exemplary, and in an actual flow, step S603a may occur in a handover procedure before the terminal sends the TAU request message to the MME in step S601.

S604, the MME executes other steps of the TAU process and sends a TAU acceptance message to the terminal.

It should be noted that details of the TAU procedure are not repeated here. S604 may be executed before S603, or may be executed after S603, which is not specifically limited in this embodiment of the application. The timing of the various steps in the figures is not intended to be limiting.

It should also be noted that there may be one or more sessions to be recovered, and the processing procedure of each session to be recovered is the same in the scheme of the present application.

It should be noted that, during the process of switching from 5G to 4G, for sessions for which the base station of the 4G network does not allocate radio resources to its bearer, the MME determines whether these sessions are sessions to be resumed in the TAU process through the processes of S601 to S604 described above, and allocates radio resources of the 4G network to the determined sessions to be resumed. Thereafter, the MME initiates a session release for the session that is not determined to be resumed and which carries unallocated radio resources.

Further, optionally, in the process of switching from 5G to 4G, if the base station of the 4G network does not allocate radio resources for bearers of some sessions, and bearers corresponding to the sessions are not rejected by the base station (that is, the bearers of the sessions are not included in the bearer list in which the establishment fails), the MME determines, through the processes of S601 to S604 described above, whether the sessions are sessions to be recovered in the TAU procedure, and allocates radio resources of the 4G network to the determined sessions to be recovered. Thereafter, the MME initiates a session release for the session that is not determined to be resumed and which carries unallocated radio resources.

By the communication method provided by the embodiment of the application, the terminal uses the same session to send the service data before the cross-system switching, so that the service continuity is ensured.

The operations of the MME or the terminal network element in steps S601 to S604 may be executed by the processor 501 in the communication apparatus 50 shown in fig. 5 calling the application program code stored in the memory 503, which is not limited in this embodiment.

On the other hand, the embodiment of the application provides a session activation method. The session activation method provided by the present application is described in detail by taking the communication system shown in fig. 2 as an interworking architecture between a 4G network and a 5G network shown in fig. 3 or fig. 3a or fig. 4, taking an example that the mobility management network element is AMF and the control plane function network element is PGW-C + SMF. A session is referred to as a PDU session in a 5G network. It should be understood that the embodiments of the present application only describe the scheme of the present application by taking the architecture of the 5G network as an example, and do not specifically limit the application scenario of the scheme of the present application.

As shown in fig. 7, a session activation method provided in an embodiment of the present application may include the following steps:

s701, the terminal sends a service request to the AMF under the condition that the terminal enters a connection state from an idle state.

In a possible implementation, the service request may be a service request for a terminal in a current service flow to enter a connected state from an idle state.

In another possible implementation, the service request includes a session identifier of the PDU session to be activated, which is determined by the terminal. Based on this, as shown in fig. 7, the session activation method provided in the embodiment of the present application may further include an optional step S701a before S701.

S701a, the terminal determines that the PDU session is to be activated.

Since the 5G network supports selective activation of PDU sessions such that a portion of PDU sessions are inactive, inactive PDU sessions do not allocate radio resources in the 5G network. The PDU session to be activated is a PDU session needing to be allocated with wireless resources, the session to be activated is established through the 5G network, and the session to be activated comprises a part of sessions or all sessions in the session allocated with the EBI. The terminal can obtain the information of each PDU session according to the PDU session context stored in the terminal, including whether the EBI is distributed and whether the EBI is activated.

In one possible implementation, the terminal determines that a 4G PDU session can be switched to as a session to be activated. If an EBI has been allocated for a PDU session in the 5G network, the PDU session may be switched to 4G. The terminal determines whether the PDU session can be switched to 4G according to whether the PDU session is allocated with corresponding EBI; the terminal may select all or part of the PDU sessions from among the PDU sessions that may be switched to 4G but not activated as the sessions to be activated.

In one possible implementation, the terminal selects all PDU sessions with EBI allocated as sessions to be activated.

In another possible implementation, the terminal may select a partial session or a full session from all PDU sessions allocated with EBI as the sessions to be activated according to a preset policy.

The terminal takes the service needing to keep the continuity as the preset service, and defines the content of the preset strategy as a session bearing the preset service as a session to be activated. Alternatively, the preset policy may also define that a session corresponding to a certain DNN and/or network slice is a session to be activated. Of course, the content of the preset policy may be configured according to actual requirements, which is not specifically limited in this embodiment of the application.

For example, the preset policy may be a local policy or a URSP policy.

Exemplarily, a local policy of a terminal configures that a session corresponding to an IMS service needs to maintain continuity when performing cross-system handover, and the terminal determines that a PDU session allocated with EBI is a session to be activated if an APN corresponding to the PDU session is the same as an APN corresponding to the IMS service. The terminal may determine the APN corresponding to the IMS according to the policy of the URSP (for example, the APN corresponding to the IMS service is configured in the URSP). Or, the terminal may also determine whether the PDU session allocated with the EBI is a session to be activated according to whether a service carried by the PDU session allocated with the EBI is a preset service, for example, if a low-latency service is currently carried on one PDU session allocated with the EBI and the preset service is a low-latency service, the terminal takes the PDU session as the session to be activated.

In one possible implementation, a terminal receives indication information from a PGW-C + SMF in a session establishment process, where the indication information is used to indicate a session that needs to be permanently online; correspondingly, the terminal determines the session to be activated, which may specifically be implemented as: and the terminal determines the session needing to be permanently online as the session to be activated in the session allocated with the radio bearer identifier.

It should be noted that, the above methods for determining the session to be activated by the terminal are all described as examples, and are not limited to this specifically. In actual application, the terminal can be configured according to actual requirements to determine a specific implementation scheme of the session to be recovered.

S702, the AMF determines the session to be activated.

Optionally, the AMF determines, in S702, that the specific implementation of the session to be activated may include, but is not limited to, the following three specific implementations (specific implementation a, specific implementation B, and specific implementation C).

Specifically, the implementation A: and determining a session to be activated by the terminal and informing the MME.

Corresponding to the specific implementation a, the service request sent by the terminal in S701 includes a session identifier of a session to be activated, which is determined by the terminal, and S702 is specifically implemented as: and the AMF determines the session indicated by the session identification included in the service request as the session to be activated.

Specifically, the implementation B: the pending session is determined by the AMF itself.

In implementation B, the AMF may learn information about each PDU session, including whether an EBI is allocated.

In one possible implementation, the AMF determines a part of or all of the PDU sessions that can be switched to 4G as the sessions to be activated. If an EBI has been allocated for a PDU session in the 5G network, the PDU session may be switched to 4G. The AMF determines whether the session can be switched to 4G according to whether the PDU session is allocated a corresponding EBI.

In one possible implementation, the AMF selects all PDU sessions that are allocated EBI and not active as sessions to be activated.

In another possible implementation, the AMF may select a partial session or a full session from all PDU sessions allocated with EBIs as the session to be activated according to a preset policy. For specific implementation, reference may be made to a process in which the terminal selects a part of sessions or all sessions from all PDU sessions allocated with the EBI as sessions to be activated according to a preset policy in S701, which is not described herein again.

In one possible implementation, in the session establishment process, the AMF receives indication information from the PGW-C + SMF, where the indication information is used to indicate a session that needs to be permanently online; correspondingly, the AMF determines the session to be activated, which may specifically be implemented as: and the AMF determines the session needing to be permanently online as the session to be activated in the session allocated with the EBI, wherein the indication information indicates the session to be permanently online.

In a possible implementation, the AMF may determine whether the PDU session needs to be permanently online according to the subscription, and determine the session that needs to be permanently online as the session to be activated in the session to which the radio bearer identifier is allocated according to the subscription information.

It should be noted that, the above-mentioned method for determining the session to be activated by the AMF is all exemplary descriptions, and is not specifically limited thereto. In actual application, the AMF may be configured according to actual requirements to determine a specific implementation scheme of a session to be recovered.

The specific implementation C, the terminal and the AMF all determine the session to be activated.

Corresponding to the specific implementation C, the service request sent by the terminal in S701 includes the session identifier of the session to be activated determined by the terminal, after receiving the service request, the AMF determines whether there are other PDU sessions to be activated according to the scheme AMF in the specific implementation B, and the AMF determines all the sessions indicated by the session identifier included in the service request and the sessions to be activated determined by the AMF as the sessions to be activated.

It should be noted that, when the service request of the terminal is used to change the terminal from the idle state to the connected state (i.e., the AMF is in the idle state when receiving the service request message), the AMF performs the specific implementations B and C.

S703, the AMF sends an activation request to the PGW-C + SMF corresponding to the session to be activated.

The activation request comprises a session identifier of the session to be activated, and the activation request is used for activating the session to be activated.

S704, PDU conversation activating flow.

The PDU session activation process can be referred to as the service request process of the existing TS 23.502. After the PDU session is activated, the bearer context corresponding to the session is stored in the corresponding base station, so that when the terminal is handed over from the 5G network to the 4G network, the AMF may send the bearer information corresponding to the PDU session to the target 4G access device as the content of the transparent container, so that the sessions can be successfully handed over to the 4G network, and the IP address is kept unchanged.

It should also be noted that there may be one or more sessions to be activated, and the processing procedure of each session to be activated is the same in the scheme of the present application.

By the session activation method, service interruption caused by session release of the target network due to non-activation is avoided, service data before and after network switching of the terminal are sent by using the same session, and continuity of terminal services during cross-system switching is guaranteed.

The actions of the AMF or the PGW-C + SMF network element in steps S701 to S704 may be executed by the processor 501 in the communication apparatus 50 shown in fig. 5 calling the application program code stored in the memory 503, which is not limited in this embodiment.

The above-mentioned scheme provided by the embodiment of the present application is introduced mainly from the perspective of interaction between network elements. It is to be understood that the mobility management element and the terminal described above, for implementing the above functions, include corresponding hardware structures and/or software modules for performing the respective functions. Those of skill in the art would 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 functional modules may be divided according to the above method example for the mobility management network element and the terminal, for example, each functional module may be divided corresponding to each function, or two or more functions may be integrated into one processing module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. It should be noted that, in the embodiment of the present application, the division of the module is schematic, and is only one logic function division, and there may be another division manner in actual implementation.

For example, in the case of dividing each functional module in an integrated manner, fig. 8 shows a schematic structural diagram of a mobility management network element 80. The mobility management element 80 includes: a determination module 801 and a processing module 802. A determining module 801, configured to determine, in a case where the terminal is handed over from the first network to the second network, a session to be resumed, where the session to be resumed is a session that needs to allocate a wireless resource in the second network, and the session to be resumed is already established through the first network, but the first network does not allocate a wireless resource for the session to be resumed. A processing module 802, configured to allocate radio resources of the second network for a bearer of the session to be resumed.

Optionally, as shown in fig. 8, the mobility management element 80 further includes a transceiver module 803, configured to receive a TAU request from the terminal, where the TAU request carries the first indication information. The determining module 801 is specifically configured to: and determining the session to be recovered according to the first indication information.

Optionally, the first indication information is an access point name corresponding to the session to be resumed, and the determining module 801 is specifically configured to: and determining the session corresponding to the access point name to be recovered.

Optionally, the first indication information is a bearer state of the session to be recovered, and the determining module 801 is specifically configured to: and determining the session with the bearing state as a preset state and without the wireless resource allocation as the session to be recovered.

Optionally, the processing module 802 is specifically configured to: acquiring the identifier of a control plane function network element corresponding to the session to be recovered from the context corresponding to the second network; sending a request message to a control plane function network element; receiving bearing information of a session to be recovered from a control plane function network element; and requesting the access equipment of the second network to allocate the wireless resources of the second network for the bearer of the session to be recovered.

In a specific implementation, the transceiver module 803 may send a request message to the control plane function network element, and receive bearer information of a session to be recovered from the control plane function network element.

Optionally, as shown in fig. 8, the mobility management element 80 further includes a storage module 804, configured to store a context corresponding to the session to be restored in the second network. Then, the processing module 802 is specifically configured to: acquiring the identifier of the control plane function network element corresponding to the session to be restored from the context corresponding to the second network of the session to be restored stored in the storage module 804; sending a request message to the control plane function network element through the transceiving module 803; receiving, by the transceiver module 803, bearer information of a session to be restored from the control plane function network element; and requesting the access equipment of the second network to allocate the wireless resources of the second network for the bearer of the session to be recovered.

Optionally, the processing module 802 is specifically configured to: and sending a bearer creating request to the access equipment of the second network according to the bearer context of the session to be recovered in the context corresponding to the second network, wherein the bearer creating request is used for allocating the radio resources of the second network to the bearer of the session to be recovered. In a specific implementation, the create bearer request may be sent to the access device of the second network through the transceiver module 803.

All relevant contents of each step related to the above method embodiment may be referred to the functional description of the corresponding functional module, and are not described herein again.

In the present embodiment, the mobility management element 80 is presented in the form of dividing the respective functional modules in an integrated manner. A "module" herein may refer to a particular ASIC, a circuit, a processor and memory that execute one or more software or firmware programs, an integrated logic circuit, and/or other device that provides the described functionality. In a simple embodiment, it will be appreciated by those skilled in the art that the mobility management element 80 may take the form shown in figure 5.

For example, the processor 501 in fig. 5 may cause the mobility management element 80 to execute the communication method (which may also be referred to as a session handover method) in the above-described method embodiment by calling a computer stored in the memory 503 to execute the instructions.

In particular, the functions/implementation procedures of the determination module 801, the transceiver module 803 and the processing module 802 in fig. 8 can be implemented by the processor 501 in fig. 5 calling a computer stored in the memory 503 to execute instructions. Alternatively, the functions/implementation procedures of the determination module 801 and the processing module 802 in fig. 8 may be implemented by the processor 501 in fig. 5 calling a computer executing instruction stored in the memory 503, and the functions/implementation procedures of the transceiver module 803 in fig. 8 may be implemented by the communication interface 504 in fig. 5.

Since the mobility management element 80 provided in this embodiment can execute the above-mentioned communication method, the technical effect obtained by the mobility management element can refer to the above-mentioned method embodiment, and is not described herein again.

Optionally, an apparatus (for example, the apparatus may be a system on a chip) is further provided in this embodiment of the present application, where the apparatus includes a processor, configured to support the apparatus to implement the foregoing communication method, for example, determine a session to be resumed, and allocate radio resources of a second network for a bearer of the session to be resumed. In one possible design, the apparatus further includes a memory. The memory is used for storing program instructions and data necessary for the device. Of course, the memory may not be in the device. When the device is a chip system, the device may be composed of a chip, and may also include a chip and other discrete devices, which is not specifically limited in this application embodiment.

Alternatively, for example, in the case of dividing each functional module in an integrated manner, fig. 9 shows a schematic structural diagram of an apparatus 90. The device 90 may be a terminal or a chip within a terminal. The apparatus 90 comprises: a processing module 901 and a transceiver module 902. A processing module 901, configured to determine a session to be resumed, where the session to be resumed is a session that needs to allocate radio resources in the second network, and the session to be resumed is already established by the first network, but the first network does not allocate radio resources for the session to be resumed. A transceiver module 902, configured to send a TAU request to a target mobility management network element, where the TAU request carries first indication information, and the first indication information is used to indicate information of a session to be resumed.

Optionally, the processing module 901 is specifically configured to: and determining part of or all of the inactivated sessions which are allocated with the radio bearer identifications as the sessions to be recovered.

Optionally, the processing module 901 is specifically configured to: and selecting a part of or all the sessions from the inactive sessions which are allocated with the radio bearer identifications as the sessions to be recovered according to a preset strategy.

In the present embodiment, the apparatus 90 is presented in the form of dividing each functional module in an integrated manner. A "module" herein may refer to a particular ASIC, a circuit, a processor and memory that execute one or more software or firmware programs, an integrated logic circuit, and/or other device that provides the described functionality. In a simple embodiment, one skilled in the art will appreciate that the device 90 may take the form shown in FIG. 5.

For example, the processor 501 in fig. 5 may execute the instructions by calling a computer stored in the memory 503, so that the apparatus 90 executes the communication method in the above method embodiment.

Specifically, the functions/implementation procedures of the transceiver module 902 and the processing module 901 in fig. 9 can be implemented by the processor 501 in fig. 5 calling a computer executing instruction stored in the memory 503. Alternatively, the function/implementation procedure of the processing module 901 in fig. 9 may be implemented by the processor 501 in fig. 5 calling a computer executing instruction stored in the memory 503, and the function/implementation procedure of the transceiver module 902 in fig. 9 may be implemented by the communication interface 504 in fig. 5.

Since the apparatus 90 provided in this embodiment can perform the above-mentioned communication method, the technical effects obtained by the apparatus can refer to the above-mentioned method embodiment, and are not described herein again.

Optionally, an embodiment of the present application further provides an apparatus (for example, the apparatus may be a system on a chip), where the apparatus includes a processor, configured to support the apparatus to implement the foregoing communication method, for example, determine a session to be resumed, and send a tracking area update TAU request to a target mobility management network element, where the TAU request carries first indication information, and the first indication information is used to indicate information of the session to be resumed. In one possible design, the apparatus further includes a memory. The memory is used for storing program instructions and data necessary for the device. Of course, the memory may not be in the device. When the device is a chip system, the device may be composed of a chip, and may also include a chip and other discrete devices, which is not specifically limited in this application embodiment.

Or, for example, in the case that the functional modules are divided in an integrated manner, fig. 10 shows a schematic structural diagram of the mobility management network element 100. The mobility management network element 100 comprises: a processing module 1001 and a transceiver module 1002. The processing module 1001 is configured to determine a session to be activated, where the session to be activated includes a part of a session or all of sessions to which a radio bearer identifier is assigned; the transceiver module 1002 is configured to send an activation request to a control plane function network element corresponding to a session to be activated, where the activation request includes a session identifier of the session to be activated.

Optionally, the processing module 1001 is specifically configured to: and selecting partial sessions or all sessions from the sessions allocated with the radio bearer identifications as sessions to be activated according to a preset strategy.

Optionally, the preset policy may include taking a session carrying the preset service as a session to be activated, and correspondingly, the processing module 1001 is specifically configured to take a session carrying the preset service and assigned with the radio bearer identifier as a session to be activated.

Optionally, the transceiver module 1002 is further configured to receive indication information from a control plane function network element, where the indication information is used to indicate a session that needs to be permanently online; correspondingly, the processing module 1001 is specifically configured to determine, as a session to be activated, a session that needs to be permanently online and is indicated by the indication information in the session to which the radio bearer identifier is assigned.

In the present embodiment, the mobility management element 100 is presented in the form of dividing each functional module in an integrated manner. A "module" herein may refer to a particular ASIC, a circuit, a processor and memory that execute one or more software or firmware programs, an integrated logic circuit, and/or other device that provides the described functionality. In a simple embodiment, it will be appreciated by those skilled in the art that the mobility management element 100 may take the form shown in fig. 5.

For example, the processor 501 in fig. 5 may cause the mobility management element 100 to execute the session activation method in the above-described method embodiment by calling a computer stored in the memory 503 to execute the instructions.

Specifically, the functions/implementation procedures of the transceiver module 1002 and the processing module 1001 in fig. 10 can be implemented by the processor 501 in fig. 5 calling a computer executing instructions stored in the memory 503. Alternatively, the function/implementation procedure of the processing module 1001 in fig. 10 may be implemented by the processor 501 in fig. 5 calling a computer executing instruction stored in the memory 503, and the function/implementation procedure of the transceiver module 1002 in fig. 10 may be implemented by the communication interface 504 in fig. 5.

Since the mobility management element 100 provided in this embodiment can execute the session activation method, the technical effect obtained by the mobility management element 100 can refer to the method embodiment described above, and is not described herein again.

Optionally, an apparatus (for example, the apparatus may be a system on a chip) is further provided in an embodiment of the present application, where the apparatus includes a processor, configured to enable the apparatus to implement the session activation method, for example, determine a session to be activated, where the session to be activated includes a part of a session or a whole session in the session to which the radio bearer identity is assigned; and sending an activation request to a control plane function network element corresponding to the session to be activated, wherein the activation request comprises a session identifier of the session to be activated. In one possible design, the apparatus further includes a memory. The memory is used for storing program instructions and data necessary for the device. Of course, the memory may not be in the device. When the device is a chip system, the device may be composed of a chip, and may also include a chip and other discrete devices, which is not specifically limited in this application embodiment.

Alternatively, for example, in the case where the functional modules are divided in an integrated manner, fig. 11 shows a schematic configuration diagram of the terminal 110. The terminal 110 includes: a processing module 1101 and a transceiver module 1102.

The processing module 1101 is configured to determine a session to be activated, where the session to be activated includes a part of or all of the sessions to which the radio bearer identity is assigned. The transceiver module 1102 is configured to send a service request to the mobility management element when the terminal 110 enters a connected state from an idle state, where the service request includes a session identifier of a session to be activated, and the service request is used to request activation of the session to be activated.

Optionally, the processing module 1101 is specifically configured to: and determining part of or all of the sessions allocated with the radio bearer identifications as sessions to be activated according to a preset strategy.

Optionally, the preset policy may include taking a session carrying a preset service as a session to be activated, and accordingly, the processing module 1101 is specifically configured to: and taking the session carrying the preset service and allocated with the radio bearer identification as the session to be activated.

Optionally, the transceiver module 1102 is further configured to receive indication information from the control plane function network element, where the indication information is used to indicate a session that needs to be permanently online; correspondingly, the processing module 1101 is specifically configured to: and determining the session needing to be permanently online in the session assigned with the radio bearer identification as the session to be activated.

In the present embodiment, the terminal 110 is presented in a form of dividing each functional module in an integrated manner. A "module" herein may refer to a particular ASIC, a circuit, a processor and memory that execute one or more software or firmware programs, an integrated logic circuit, and/or other device that provides the described functionality. In a simple embodiment, those skilled in the art will appreciate that the terminal 110 may take the form shown in FIG. 5.

For example, the processor 501 in fig. 5 may execute the instructions by calling a computer stored in the memory 503, so that the terminal 110 executes the session activation method in the above method embodiment.

Specifically, the functions/implementation processes of the transceiver module 1102 and the processing module 1101 in fig. 11 can be implemented by the processor 501 in fig. 5 calling a computer executing instruction stored in the memory 503. Alternatively, the function/implementation procedure of the processing module 1101 in fig. 11 may be implemented by the processor 501 in fig. 5 calling a computer executing instruction stored in the memory 503, and the function/implementation procedure of the transceiver module 1102 in fig. 11 may be implemented by the communication interface 504 in fig. 5.

Since the terminal 110 provided in this embodiment can execute the session activation method, the technical effects obtained by the terminal 110 can refer to the method embodiments described above, and are not described herein again.

Optionally, an apparatus (for example, the apparatus may be a system on a chip) is further provided in an embodiment of the present application, where the apparatus includes a processor, configured to enable the apparatus to implement the session activation method, for example, determine a session to be activated, where the session to be activated includes a part of a session or a whole session in the session to which the radio bearer identity is assigned; and sending a service request to a mobile management network element under the condition that the device enters a connected state from an idle state, wherein the service request comprises a session identifier of the session to be activated, and the service request is used for requesting to activate the session to be activated. In one possible design, the apparatus further includes a memory. The memory is used for storing program instructions and data necessary for the device. Of course, the memory may not be in the device. When the device is a chip system, the device may be composed of a chip, and may also include a chip and other discrete devices, which is not specifically limited in this application embodiment.

In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof. When implemented using a software program, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. The procedures or functions described in accordance with the embodiments of the present application are all or partially generated upon loading and execution of computer program instructions on a computer. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored on a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, from one website, computer, server, or data center to another website, computer, server, or data center via wire (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or can comprise one or more data storage devices, such as a server, a data center, etc., that can be integrated with the medium. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., Solid State Disk (SSD)), among others.

While the present application has been described in connection with various embodiments, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed application, from a review of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the word "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Although the present application has been described in conjunction with specific features and embodiments thereof, it will be evident that various modifications and combinations can be made thereto without departing from the spirit and scope of the application. Accordingly, the specification and figures are merely exemplary of the present application as defined in the appended claims and are intended to cover any and all modifications, variations, combinations, or equivalents within the scope 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.

Claims

1. A communication method, characterized in that after a terminal is handed over from a first network to a second network, the method comprises:

a target mobile management network element determines a session to be recovered, wherein the session to be recovered is a session requiring allocation of radio resources in the second network, the session to be recovered is already established by the first network, but the first network does not allocate radio resources to the session to be recovered;

and the target mobile management network element allocates the radio resource of the second network for the bearing of the session to be recovered.

2. The communication method of claim 1, wherein the determining, by the target mobility management element, the session to be resumed comprises:

the target mobile management network element receives a tracking area update TAU request from the terminal, wherein the TAU request carries first indication information;

and the target mobile management network element determines the session to be recovered according to the first indication information.

3. The communication method according to claim 2, wherein the first indication information is an access point name corresponding to the session to be resumed.

4. The communication method according to any one of claims 1 to 3, wherein the allocating, by the target mobility management network element, the radio resources of the second network for the bearer of the session to be resumed comprises:

the target mobility management network element acquires the identifier of the control plane function network element corresponding to the session to be recovered from the context corresponding to the session to be recovered in the second network;

the target mobile management network element sends a request message to the control plane function network element;

the target mobility management network element receives the bearing information of the session to be recovered from the control plane function network element;

and the target mobile management network element requests the access equipment of the second network to allocate the radio resource of the second network for the bearer of the session to be recovered.

5. The communication method according to claim 2, wherein the first indication information is a bearer status of the session to be resumed;

the determining, by the target mobility management network element according to the first indication information, the session to be restored includes:

and the target mobile management network element determines the session of which the bearing state is a preset state and which is not allocated with the wireless resource as the session to be recovered.

6. The communication method of claim 1, wherein the determining, by the target mobility management element, the session to be resumed comprises:

and the target mobile management network element determines a part of session or all session which is not allocated with radio resources and the bearer of which is not included in the session of the radio bearer list with failed establishment as the session to be recovered.

7. The communication method of claim 1, wherein the method further comprises:

the target mobility management network element receiving a second indication from a source mobility management network element, the second indication indicating an inactive session in the first network;

correspondingly, the determining, by the target mobility management network element, the session to be resumed includes:

and the target mobility management network element determines part of or all of the sessions which are not activated in the first network as the sessions to be recovered according to the second indication.

8. The communication method according to any one of claims 1 to 3 or 5 to 7, wherein the allocating, by the target mobility management network element, the radio resources of the second network for the bearer of the session to be resumed comprises:

and the target mobility management network element sends a bearer creation request to the access device of the second network according to the bearer context of the session to be restored in the context corresponding to the second network, wherein the bearer creation request is used for allocating the radio resources of the second network to the bearer of the session to be restored.

9. The communication method according to any one of claims 1 to 8, wherein the method further comprises:

and the target mobile management network element acquires the context corresponding to the session to be recovered in the second network.

10. A communication method, wherein after a terminal is handed over from a first network to a second network, the method comprises:

the terminal determines a session to be recovered, wherein the session to be recovered is a session needing to allocate wireless resources in the second network, the session to be recovered is already established through the first network, but the first network does not allocate wireless resources for the session to be recovered;

the terminal sends a tracking area update TAU request to a target mobile management network element, wherein the TAU request carries first indication information, and the first indication information is used for indicating the information of the session to be recovered.

11. The communication method according to claim 10, wherein the terminal determines that the session is to be resumed, and comprises:

and the terminal determines part of or all of the inactivated sessions which are allocated with the radio bearer identifications as the sessions to be recovered.

12. The communication method according to claim 10, wherein the terminal determines that the session is to be resumed, and comprises:

and the terminal selects a part of or all of the sessions from the inactivated sessions allocated with the radio bearer identifications as the sessions to be recovered according to a preset strategy.

13. The communication method according to claim 12, wherein the preset policy includes taking a session carrying a preset service as the session to be resumed.

14. The communication method according to any one of claims 10 to 13,

the first indication information is an access point name corresponding to the session to be recovered;

alternatively, the first and second electrodes may be,

the first indication information is the bearing state of the session to be recovered.

15. A method of session activation, the method comprising:

the method comprises the steps that a mobility management network element determines a session to be activated, wherein the session to be activated comprises a part of session or all session in the session distributed with a radio bearer identifier;

and the mobility management network element sends an activation request to a control plane function network element corresponding to the session to be activated, wherein the activation request comprises a session identifier of the session to be activated.

16. A method of session activation, the method comprising:

the terminal determines a session to be activated, wherein the session to be activated comprises a part of or all of the sessions which are allocated with radio bearer identifications;

and under the condition that the terminal enters a connection state from an idle state, the terminal sends a service request to a mobile management network element, wherein the service request comprises a session identifier of the session to be activated, and the service request is used for requesting to activate the session to be activated.

17. A mobility management element, wherein the mobility management element is a mobility management element in a second network, and wherein the mobility management element comprises: a determining module and a processing module;

the determining module is configured to determine a session to be resumed, where the session to be resumed needs to allocate radio resources in the second network, and the session to be resumed is already established by a first network, but the first network does not allocate radio resources to the session to be resumed;

the processing module is configured to allocate radio resources of the second network to the bearer of the session to be resumed.

18. The mobility management element according to claim 17, wherein the mobility management element further comprises a transceiver module;

the receiving and sending module is used for receiving a tracking area update TAU request from the terminal, wherein the TAU request carries first indication information;

the determining module is specifically configured to determine the session to be resumed according to the first indication information.

19. The mobility management element according to claim 18, wherein the first indication information is an access point name corresponding to the session to be resumed.

20. Mobility management network element according to any of claims 17-19,

the processing module is specifically configured to: acquiring the identifier of the control plane function network element corresponding to the session to be recovered from the context corresponding to the second network; sending a request message to the control plane function network element; receiving the bearing information of the session to be recovered from the control plane function network element; requesting the access equipment of the second network to allocate the wireless resource of the second network for the bearer of the session to be recovered.

21. The mobility management element according to claim 18, wherein the first indication information is a bearer status of the session to be resumed;

the determining module is specifically configured to: and determining the session with the bearing state as a preset state and without the allocation of the wireless resources as the session to be recovered.

22. The mobility management element according to claim 17, wherein the determining module is specifically configured to:

and determining a part of sessions or all sessions, which are not allocated with radio resources and the bearers of which are not included in the session of the radio bearer list with failed establishment, as the session to be recovered.

23. The mobility management network element according to claim 17,

the mobility management element further comprises a transceiver module configured to receive a second indication from a source mobility management element, where the second indication indicates an inactive session in the first network;

correspondingly, the determining module is specifically configured to: and according to the second indication, determining a part of or all of the sessions which are not activated in the first network as the session to be recovered.

24. The mobility management element according to any of claims 17-19 or 21-23, wherein the processing module is specifically configured to:

and sending a bearer creating request to the access equipment of the second network according to the bearer context of the session to be recovered in the context corresponding to the second network, wherein the bearer creating request is used for allocating the radio resources of the second network to the bearer of the session to be recovered.

25. The mobility management element according to any of claims 17-24, wherein the processing module is further configured to: and obtaining the context corresponding to the session to be recovered in the second network.

26. An apparatus, characterized in that the apparatus comprises: the device comprises a processing module and a transmitting-receiving module;

the processing module is configured to determine a session to be resumed, where the session to be resumed needs to allocate wireless resources in a second network, and the session to be resumed is already established by a first network, but the first network does not allocate wireless resources to the session to be resumed;

the receiving and sending module is configured to send a tracking area update TAU request to a target mobility management network element, where the TAU request carries first indication information, and the first indication information is used to indicate the information of the session to be resumed.

27. The apparatus of claim 26, wherein the processing module is specifically configured to:

and determining part of or all of the sessions which are allocated with the radio bearer identifications and are not activated as the session to be recovered.

28. The apparatus of claim 26, wherein the processing module is specifically configured to:

and selecting a part of sessions or all sessions from the inactive sessions which are allocated with the radio bearer identifications as the sessions to be recovered according to a preset strategy.

29. A mobility management element, wherein the mobility management element comprises: the device comprises a processing module and a transmitting-receiving module;

the processing module is used for determining a session to be activated, wherein the session to be activated comprises a part of or all of the sessions allocated with radio bearer identifications;

the transceiver module is configured to send an activation request to a control plane function network element corresponding to the session to be activated, where the activation request includes a session identifier of the session to be activated.

30. A terminal, characterized in that the terminal comprises: the device comprises a processing module and a transmitting-receiving module;

the receiving and sending module is configured to send a service request to a mobility management element when the terminal enters a connected state from an idle state, where the service request includes a session identifier of the session to be activated, and the service request is used to request activation of the session to be activated.

31. A communication system, the system comprising: a mobility management network element and a terminal;

the mobility management network element is configured to determine a session to be resumed after the terminal is switched from the first network to the second network; the session to be recovered is a session requiring allocation of radio resources in the second network, the session to be recovered is already established by the first network, but the first network does not allocate radio resources for the session to be recovered;

the mobility management network element is further configured to allocate radio resources of the second network to the bearer of the session to be resumed.

32. A session activation system, the system comprising: a mobility management network element and a control plane function network element;

the mobility management network element is configured to determine a session to be activated, where the session to be activated includes a part of or all of sessions to which a radio bearer identifier is assigned;

the mobility management network element is further configured to send an activation request to the control plane function network element corresponding to the session to be activated, where the activation request includes a session identifier of the session to be activated.