CN114126037A

CN114126037A - Communication method, device and system

Info

Publication number: CN114126037A
Application number: CN202010914044.0A
Authority: CN
Inventors: 张成晨; 朱强华
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2020-09-01
Filing date: 2020-09-01
Publication date: 2022-03-01
Also published as: WO2022048392A1

Abstract

The embodiment of the application provides a communication method, a communication device and a communication system, which relate to the technical field of communication and are used for facilitating that a terminal does not need to initiate periodic registration when a periodic registration timer expires after leaving a first system, and the terminal cannot be implicitly deregistered by a network side temporarily even if the terminal does not initiate periodic registration when the periodic registration timer expires. The scheme comprises the following steps: an access and mobility management (AMF) network element in a first system receives first information from a first terminal, equipment where the first terminal is located is provided with a plurality of global user identification cards, the first terminal corresponds to a first global user identification card in the plurality of global user identification cards, and the first system is a system accessed by the first terminal. And the AMF network element sends a first indication to the first terminal according to the first information, wherein the first indication indicates that the first terminal is allowed not to perform periodic registration after entering an idle state in the first system because the first terminal leaves the first system.

Description

Communication method, device and system

Technical Field

The embodiment of the application relates to the technical field of communication, in particular to a communication method, device and system.

Background

For a terminal registered to a network by a 3rd Generation Partnership Project (3 GPP) access technology, periodic registration needs to be performed after entering an idle state in order for the network to know whether the terminal still needs to be connected to the network. If the terminal is not registered periodically in time, the terminal is implicitly unregistered by the network, so that the relevant information (such as the context information and the session information of the terminal) of the terminal is deleted.

For a terminal with Multiple Universal Subscriber Identity Module (MUSIM) cards, the terminal may choose to leave the communication system corresponding to one of the cards (hereinafter referred to as the current system) and enter the communication system corresponding to the other card. In this case, the terminal enters an idle state in the current system, and if the terminal does not return to the current system in time, implicit deregistration may be caused. If implicit de-registration occurs, because the network side deletes the relevant information of the terminal, if the terminal needs to recover the previous communication, the terminal needs to perform re-initial registration and re-establish the session, which brings a lot of signaling and causes delay, thereby affecting the user experience.

Disclosure of Invention

The embodiment of the application provides a communication method, a communication device and a communication system, which are used for facilitating that a first terminal in equipment with a plurality of global user identification cards does not need to initiate periodic registration when a periodic registration timer expires after leaving a first system, and the first terminal cannot be implicitly unregistered by a network side temporarily even if the terminal does not initiate periodic registration when the periodic registration timer expires.

In order to achieve the purpose, the technical scheme is as follows:

in a first aspect, a communication method is provided, including: an access and mobility management, AMF, network element in a first system receives first information from a first terminal. The equipment where the first terminal is located is provided with a plurality of global user identification cards, and the first terminal corresponds to a first global user identification card in the plurality of global user identification cards. The first system is a system to which the first terminal is accessed. And the AMF network element sends a first indication to the first terminal according to the first information. The first indication is used for indicating that the first terminal is allowed not to perform periodic registration after entering an idle state in the first system.

The embodiment of the present application provides a communication method, in which a first terminal negotiates with an AMF network element in a first system by using first information, and the AMF network element may indicate, by using a first indication, to the first terminal that a network side allows a state of the first terminal in the first system to be an idle state and then does not perform periodic registration under a condition that the AMF network element does not perform periodic registration after allowing the first terminal to enter the idle state in the first system. This facilitates the first terminal determining that a periodic registration may not be initiated upon expiration of the periodic registration timer after entering an idle state in the first system. In addition, the first terminal may also determine that the first terminal is not implicitly deregistered by the network side for the moment when the periodic registration timer expires even if the first terminal does not initiate the periodic registration.

In one possible implementation manner of the present application, the entering of the first terminal into the idle state in the first system may be: the first terminal enters an idle state in the first system due to leaving the first system.

In one possible implementation manner of the present application, the entering of the first terminal into the idle state in the first system may be: the first terminal does not leave the first system and causes the first terminal to enter an idle state in the first system.

In a possible implementation manner of the present application, the first indication indicates that the first terminal is allowed to enter an idle state due to leaving the first system, and then does not perform periodic registration. This facilitates the first terminal determining that periodic registration is not to be performed after entering an idle state in the first system due to leaving the first system, and thus may not initiate periodic registration upon expiration of the periodic registration timer.

In one possible implementation manner of the present application, the method provided in the embodiment of the present application further includes: and the AMF network element determines to allow the first terminal to enter an idle state in the first system without periodic registration due to leaving the first system according to the first information.

In one possible implementation of the present application, the first information includes a suspend period registration indication. The suspend period registration indication indicates that the first terminal desires to enter an idle state in the first system without performing period registration after leaving the first system. This may explicitly indicate to the AMF network element that the first terminal expects not to perform a periodic registration after entering an idle state in the first system because it left the first system.

In one possible implementation of the application, the first information comprises a second indication indicating that the first terminal is to leave the first system. The method indicates the AMF network element that the first terminal is expected not to perform periodic registration after entering an idle state in the first system due to leaving the first system in an implicit indication mode.

In one possible implementation manner of the present application, the receiving, by an access and mobility management AMF network element in a first system, first information from a first terminal includes: the AMF network element receives a message X from the first terminal. The message X is used to indicate that the first terminal is about to leave the first system. The message X carries first information. For example, the message X may be an uplink NAS message indicating that the first terminal is about to leave the first system. The scheme can realize that when the first terminal leaves the first system, the first terminal negotiates with the AMF network element whether periodic registration is allowed to be avoided.

In one possible implementation manner of the present application, the first information is used to indicate that the first terminal is about to leave the first system, and is used to indicate to the AMF network element whether to allow the first terminal to enter an idle state in the first system without performing periodic registration after leaving the first system. The first information may then comprise a first indication and a pause period registration indication.

In one possible implementation manner of the present application, the receiving, by an access and mobility management AMF network element in a first system, first information from a first terminal includes: the AMF network element receives a third message including the first information from the first terminal. The third message is for requesting registration of the first terminal in the first system. Therefore, when the first terminal is registered in the first system, the network side can conveniently negotiate whether the first terminal is allowed to leave the first system and does not perform periodic registration after entering an idle state in the first system.

In one possible implementation manner of the present application, the method provided in the embodiment of the present application further includes: the AMF network element determines that the first terminal is not allowed to enter an idle state in the first system due to leaving the first system any more, and then does not perform periodic registration. And the AMF network element sends a third indication to the first terminal. The third indication does not allow the first terminal to enter an idle state in the first system without periodic registration due to leaving the first system. The first terminal determines that the network side does not allow the first terminal to enter an idle state in the first system due to leaving the first system through the third indication, and then does not perform periodic registration, so that the first terminal can judge whether the periodic registration is required in the first system to recover the connection with the first system after receiving the third indication. For example, the AMF network element first allows the first terminal to leave the first system and enter an idle state in the first system without performing periodic registration through the first indication. However, after sending the first indication, the core network element in the first system has data to send to the first terminal, and then the AMF network element may send a third indication to the first terminal.

In a possible implementation manner of the present application, the first system is a system in which a first global subscriber identity card of a first terminal has a first type access, and an access and mobility management AMF network element in the first system receives first information from the first terminal, including: the AMF network element receives the first information from the first terminal through the second type access. Alternatively, the AMF network element receives the first information from the first terminal through the first network element. The scheme can realize the process of negotiating with the AMF network element whether to allow the non-periodic registration after the first terminal leaves the first system.

In a possible implementation manner of the present application, the first system is a system in which a first global subscriber identity card of the first terminal accesses the first type, and the AMF network element sends a first indication to the first terminal according to the first information, where the method includes: and the AMF network element sends the first indication to the first terminal through the second type access or the first network element.

In one possible implementation manner of the present application, the method provided in the embodiment of the present application may further include: the AMF network element transmits the first time value to the first terminal. The first time value is used to indicate a first timer duration for implicit de-registration of the first terminal in the first system. This facilitates the first terminal determining that it will not be implicitly de-registered by the AMF network element even if it does not periodically register before the expiration of the first timer for implicit de-registration.

In one possible implementation manner of the present application, the method provided in the embodiment of the present application may further include: and after the first terminal is changed from the connection state to the idle state in the AMF network element, the AMF network element skips the starting of the mobile reachable timer. I.e. the AMF network element does not start the mobile reachable timer.

In one possible implementation manner of the present application, the method provided in the embodiment of the present application may further include: and after the first terminal is changed from a connection state to an idle state in the AMF network element, the AMF network element starts an implicit de-registration timer. The implicit de-registration timer has a duration greater than or equal to a first time value. This ensures that the first terminal has not been implicitly de-registered by the AMF network element after the first time value, so that the first terminal can quickly resume the connection with the first system before the duration of the implicit de-registration timer.

In one possible implementation manner of the present application, the method provided in the embodiment of the present application may further include: at a first moment, the AMF network element starts a timer. The timer is used for recording the duration of the first terminal entering the idle state in the first system due to leaving the first system, and the first time is the time when the connection state of the first terminal in the AMF network element is changed from the connection state to the idle state. And when the duration is greater than or equal to the second time value, the AMF network element performs implicit de-registration on the first terminal in the first system. The scheme can realize that the AMF network element uniformly performs implicit de-registration on a plurality of terminals (including the first terminal) with the off-network time length being greater than or equal to the second time value.

In one possible implementation manner of the present application, the method provided in the embodiment of the present application may further include: and when the first terminal leaves the first system and enters an idle state in the first system, the AMF network element sends a first message to the access network. The first message is for requesting the access network to page the first terminal and indicating in the paging message that the AMF network element is to perform implicit de-registration for the first terminal. The scheme can realize that before the first terminal is not implicitly unregistered, if the first terminal still does not recover the communication with the first system at the moment, when the AMF network element needs to send data to the first terminal, or the AMF network element prepares to implicitly unregister the terminal in advance (namely before the first time value arrives) or the AMF network element does not send the first time value to the first terminal, the first terminal is informed that the AMF network element is to implicitly unregister the first terminal, so that the first terminal determines whether to recover the connection with the first system according to the paging message.

In one possible implementation manner of the present application, the method provided in the embodiment of the present application may further include: and when the first terminal leaves the first system and enters an idle state in the first system, the AMF network element sends a second message to the first terminal through the second type access or the first network element. The second message is used to indicate that the AMF network element is to perform implicit de-registration for the first terminal.

In one possible implementation manner of the present application, the method provided in the embodiment of the present application may further include: the AMF element receives the fourth message or the fifth message from the first terminal. The fourth message is for requesting registration of the first terminal in the first system. The registration type in the fourth message is a mobile registration update. The registration type in the fifth message is initial registration, and the fifth message is used for requesting registration of the first terminal in the first system. For example, the fourth message and the fifth message may be registration request messages.

In a second aspect, an embodiment of the present application provides a communication method, including: the first terminal sends the first information to an access and mobility management, AMF, network element in the first system. The first information is used for the AMF network element to determine whether to allow the first terminal to enter an idle state in the first system for leaving the first system and then not to perform periodic registration. The equipment where the first terminal is located is provided with a plurality of global user identification cards, the first terminal corresponds to a first global user identification card in the plurality of global user identification cards, and the first system is a system accessed by the first terminal. The first terminal receives a first indication from an AMF network element. The first indication is used for indicating that the first terminal is allowed to leave the first system and not perform periodic registration after entering an idle state in the first system.

In one possible implementation of the present application, the first information includes a suspend period registration indication. The suspend period registration indication indicates that the first terminal desires not to perform period registration after entering an idle state in the first system due to leaving the first system.

In one possible implementation manner of the present application, the first information is used to indicate that the first terminal will leave the first system, and is used to indicate that the first terminal desires not to perform periodic registration after entering an idle state in the first system due to leaving the first system. For example, the first information includes a second indication and a suspend period registration indication.

In one possible implementation manner of the present application, the first information includes a second indication, and the second indication is used for indicating that the first terminal will leave the first system.

In one possible implementation manner of the present application, the first information is carried in a message X, where the message X is used to indicate that the first terminal is about to leave the first system.

In one possible implementation manner of the present application, the sending, by the first terminal, the first information to the access and mobility management AMF network element in the first system includes: and the first terminal sends a third message to the AMF network element in the first system. The third message includes the first information. Wherein the third message is for requesting registration of the first terminal in the first system.

In one possible implementation manner of the present application, the method provided in the embodiment of the present application may further include: the first terminal receives a third indication from the AMF network element. The third indication indicates that the first terminal is no longer allowed to periodically register after entering an idle state in the first system due to leaving the first system.

In a possible implementation manner of the present application, the first system is a system in which a first USIM of the first terminal accesses through a first type, and the sending, by the first terminal, first information to an access and mobility management AMF network element in the first system includes: and the first terminal sends the first information to the AMF network element through the second type access or the first network element. The scheme can be applied to the process of negotiating with the network side whether to allow the periodic registration not to be carried out after the first terminal leaves from the first system.

In one possible implementation manner of the present application, the first system is a system in which a first USIM of the first terminal accesses through the first type, and the first terminal receives the first indication from the AMF network element, including: the first terminal receives the first indication from the AMF network element through the second type access or the first network element.

In one possible implementation manner of the present application, the method provided in the embodiment of the present application may further include: the first terminal receives a first time value from the AMF network element. The first time value is used to indicate a first timer duration for implicit de-registration of the first terminal in the first system.

In one possible implementation manner of the present application, the method provided in the embodiment of the present application may further include: and at the second moment, the first terminal starts a third timer and the first timer. The value of the first timer is a first time value. The second time is the time when the state of the first terminal in the AMF network element is changed from the connection state to the idle state. And when the third timer expires, the first terminal does not actively initiate periodic registration, but stores an expired record. When the first timer expires, the first terminal performs implicit de-registration in the first system.

In one possible implementation manner of the present application, the method provided in the embodiment of the present application may further include: and at a second moment, the first terminal starts a third timer, wherein the second moment is the moment when the state of the first terminal in the AMF network element is changed from the connection state to the idle state. When the third timer expires, the first terminal does not initiate the periodic registration, but saves an expiration record of the periodic registration.

In one possible implementation manner of the present application, the method provided in the embodiment of the present application may further include: the first terminal receives a paging message from the access network, wherein the paging message is used for indicating that the AMF network element performs implicit de-registration on the first terminal. For example, the fourth indication is included in the paging message. The fourth indication indicates that the AMF network element is to perform implicit de-registration for the first terminal. Or the fourth indication may be used to indicate paging of the first terminal, which may cause the first terminal to determine that the AMF network element is to perform implicit de-registration for the first terminal.

In one possible implementation manner of the present application, the method provided in the embodiment of the present application may further include: and if the third timer expires and an expired record exists, the first terminal sends a fourth message to the AMF network element if a first condition is met. The fourth message is for requesting registration of the first terminal in the first system. The registration type in the fourth message is a mobile registration update. Wherein the first condition comprises any one or more of: and if the first timer does not expire, the first terminal receives the paging message and restores the connection with the first system within the preset time, and the first terminal does not receive the paging message or the first time value. The preset time may be carried in a paging message.

In one possible implementation manner of the present application, the method provided in the embodiment of the present application may further include: and when the first timer expires or the first terminal receives the paging message but does not respond to the paging message within the preset time, the first terminal sends a fifth message to the AMF network element. The registration type in the fifth message is initial registration, and the fifth message is used for requesting registration of the first terminal in the first system. For example, the fourth message and the fifth message may be registration request messages.

In a third aspect, an embodiment of the present application provides a communication apparatus, which may implement the method in the first aspect or any possible implementation manner of the first aspect, and therefore may also implement the beneficial effects in the first aspect or any possible implementation manner of the first aspect. The communication device may be an AMF network element, or may also be a device that supports the AMF network element to implement the method in the first aspect or any possible implementation manner of the first aspect, for example, a chip applied to the AMF network element. The communication device may implement the above method by software, hardware, or by executing corresponding software by hardware.

An example, the communication apparatus, applied in a first system, includes: a communication unit and a processing unit, the communication unit is used for receiving or sending information. The processing unit is used for processing information. The communication unit is used for receiving first information from the first terminal. The equipment where the first terminal is located is provided with a plurality of global user identification cards, and the first terminal corresponds to a first global user identification card in the plurality of global user identification cards. The first system is a system to which the first terminal is accessed. And the processing unit is used for sending a first instruction to the first terminal through the communication unit according to the first information. The first indication is used for indicating that the first terminal is allowed to leave the first system and not perform periodic registration after entering an idle state in the first system.

In a possible implementation manner of the present application, the processing unit is further configured to determine, according to the first information, that the first terminal is allowed to enter an idle state in the first system due to leaving the first system without performing periodic registration.

In one possible implementation of the present application, the first information includes a suspend period registration indication. The suspend period registration indication indicates that the first terminal desires not to perform period registration after entering an idle state in the first system due to leaving the first system. This may explicitly indicate to the AMF network element that the first terminal desires not to periodically register after entering an idle state in the first system due to leaving the first system.

In one possible implementation of the application, the first information comprises a second indication indicating that the first terminal is to leave the first system. The method indicates the AMF network element that the first terminal does not perform periodic registration after entering an idle state in the first system due to leaving the first system in an implicit indication mode.

In one possible implementation manner of the present application, the communication unit is configured to receive a message X from the first terminal, where the message X is used to indicate that the first terminal is about to leave the first system. The message X carries first information. For example, the message X may be an uplink NAS message indicating that the first terminal is about to leave the first system. The scheme can realize that when the first terminal leaves the first system, the first terminal negotiates with the AMF network element whether periodic registration is allowed to be avoided.

In one possible implementation manner of the present application, the first information is used to indicate that the first terminal is about to leave the first system, and is used to indicate to the AMF network element whether to allow the first terminal to enter an idle state in the first system due to leaving the first system without performing periodic registration. The first information may then comprise a first indication and a pause period registration indication.

In one possible implementation manner of the present application, the communication unit is configured to receive a third message including the first information from the first terminal. The third message is for requesting registration of the first terminal in the first system. Therefore, when the first terminal is registered in the first system, the network side can conveniently negotiate whether the first terminal is allowed to enter an idle state in the first system because the first terminal leaves the first system, and then periodic registration is not executed.

In a possible implementation manner of the present application, the processing unit is further configured to determine that the first terminal is no longer allowed to enter an idle state in the first system due to leaving the first system, and then do not perform periodic registration. And the communication unit is also used for sending a third instruction to the first terminal. The third indication does not allow the first terminal to enter an idle state in the first system without periodic registration due to leaving the first system. The first terminal determines that the network side does not allow the first terminal to enter an idle state in the first system due to leaving the first system through the third indication, and then does not perform periodic registration, so that the first terminal can judge whether periodic registration is required in the first system to recover the connection with the first system after receiving the third indication. For example, the AMF network element first allows the first terminal to leave the first system and enter an idle state in the first system without performing periodic registration through the first indication. However, after sending the first indication, the core network element in the first system has data to send to the first terminal, and then the AMF network element may send a third indication to the first terminal.

In a possible implementation manner of the present application, the first system is a system in which a first global subscriber identity card of the first terminal is accessed by a first type, and the communication unit is further configured to receive first information from the first terminal through an access of a second type. Alternatively, the AMF network element receives the first information from the first terminal through the first network element. The scheme can realize the process that the first terminal negotiates with the AMF network element whether to allow the non-periodic registration after leaving the first system.

In a possible implementation manner of the present application, the first system is a system in which a first global subscriber identity card of the first terminal is accessed by a first type, and the communication unit is configured to send the first indication to the first terminal through the second type access or the first network element.

In a possible implementation manner of the present application, the communication unit is further configured to send the first time value to the first terminal. The first time value is used to indicate a first timer duration for implicit de-registration of the first terminal in the first system.

In a possible implementation manner of the present application, after the first terminal changes from the connected state to the idle state in the AMF network element, the processing unit is further configured to skip execution of starting the mobile reachable timer.

In a possible implementation manner of the present application, after the first terminal changes from the connected state to the idle state in the AMF network element, the processing unit is further configured to start an implicit deregistration timer. The implicit de-registration timer has a duration greater than or equal to a first time value. This ensures that the first terminal has not been implicitly de-registered by the AMF network element after the first time value, so that the first terminal can quickly resume connection with the first system before the duration of the implicit de-registration timer.

In one possible implementation manner of the present application, at the first time, the processing unit is further configured to start a timer. The timer is used for recording the time length of the first terminal entering the idle state in the first system due to leaving the first system, and the first time is the time when the connection state of the first terminal in the AMF network element is changed from the connection state to the idle state. And when the duration is greater than or equal to the second time value, the AMF network element performs implicit de-registration on the first terminal in the first system. The scheme can realize that the AMF network element uniformly performs implicit deregistration on a plurality of terminals (including the first terminal) with the network leaving duration being greater than or equal to the second time value.

In a possible implementation manner of the present application, when the first terminal enters the idle state in the first system due to leaving the first system, the communication unit is further configured to send a first message to the access network. The first message is for requesting the access network to page the first terminal and indicating in the paging message that the AMF network element is to perform implicit de-registration for the first terminal. The scheme can realize that before the first terminal is not implicitly unregistered, if the first terminal still does not recover the communication with the first system at the moment, when the AMF network element needs to send data to the first terminal, or the AMF network element prepares to implicitly unregister the terminal in advance (namely before the first time value arrives) or the AMF network element does not send the first time value to the first terminal, the first terminal is informed that the AMF network element is about to implicitly unregister the first terminal, so that the first terminal determines whether to recover the connection with the first system according to the paging message.

In a possible implementation manner of the present application, when the first terminal enters the idle state in the first system due to leaving the first system, the communication unit is further configured to send a second message to the first terminal through the second type access or the first network element. The second message is used to indicate that the AMF network element is to perform implicit de-registration for the first terminal.

In a possible implementation manner of the present application, the communication unit is further configured to receive a fourth message or a fifth message from the first terminal. The fourth message is for requesting registration of the first terminal in the first system. The registration type in the fourth message is a mobile registration update. The registration type in the fifth message is initial registration, and the fifth message is used for requesting registration of the first terminal in the first system. For example, the fourth message and the fifth message may be registration request messages.

Illustratively, when the communication device is a chip or a system of chips within an AMF network element, the processing unit may be a processor and the communication unit may be a communication interface. For example, the communication interface may be an input/output interface, a pin or a circuit, etc. The processing unit executes the instructions stored by the storage unit to cause the AMF network element to implement the first aspect or one of the possible implementation manners of the first aspect. The memory location may be a memory location within the chip (e.g., registers, buffers, etc.) or may be a memory location external to the chip within the AMF network element (e.g., read-only memory, random access memory, etc.).

In a fourth aspect, embodiments of the present application provide a communication apparatus, which may implement the method in the second aspect or any possible implementation manner of the second aspect, and therefore may also achieve the beneficial effects in the second aspect or any possible implementation manner of the second aspect. The communication device may be the first terminal, or may be a device that supports the first terminal to implement the second aspect or the method in any possible implementation manner of the second aspect, for example, a chip applied in the first terminal. The communication device may implement the above method by software, hardware, or by executing corresponding software by hardware.

An example of the communication device, which is a first terminal or a chip system applied in a first system, includes: a communication unit for receiving or transmitting information and a processing unit. The processing unit is used for processing information. The communication unit is configured to send the first information to an access and mobility management AMF network element in the first system. The first information is used for the AMF network element to determine whether to allow the first terminal to enter an idle state in the first system for leaving the first system and then not to perform periodic registration. The equipment where the first terminal is located is provided with a plurality of global user identification cards, the first terminal corresponds to a first global user identification card in the plurality of global user identification cards, and the first system is a system accessed by the first terminal. The communication unit is further configured to receive a first indication from the AMF network element. The first indication is used for indicating that the terminal is allowed not to perform periodic registration after leaving the first system and entering an idle state in the first system.

In a possible implementation manner of the present application, the communication unit is configured to send the third message to an access and mobility management AMF network element in the first system. The third message includes the first information. Wherein the third message is for requesting registration of the first terminal in the first system.

In a possible implementation manner of the present application, the communication unit is further configured to receive a third indication from the AMF network element. The third indication indicates that the first terminal is no longer allowed to perform periodic registration after entering the idle state.

In a possible implementation manner of the present application, the first system is a system in which a first USIM of the first terminal accesses through the first type, and the communication unit is further configured to send the first information to the AMF network element through the second type access or the first network element. The scheme can be applied to the process of negotiating with the network side whether to allow the periodic registration not to be carried out after the first terminal leaves from the first system.

In a possible implementation manner of the present application, the first system is a system in which a first USIM of the first terminal accesses through the first type, and the communication unit is further configured to receive the first indication from the AMF network element through the second type access or the first network element.

In one possible implementation manner of the present application, the communication unit is further configured to receive the first time value from the AMF network element. The first time value is used to indicate a first timer duration for implicit de-registration of the first terminal in the first system.

In one possible implementation manner of the present application, at the second time, the first terminal starts the third timer and the first timer. The value of the first timer is a first time value. The second time is the time when the state of the first terminal in the AMF network element is changed from the connection state to the idle state. When the third timer expires, the processing unit is further configured to not actively initiate the periodic registration (i.e., skip the periodic registration process), but store an expiration record. The processing unit is further configured to perform implicit de-registration in the first system upon expiration of the first timer.

In a possible implementation manner of the present application, at the second time, the processing unit is further configured to start a third timer, where the second time is a time when the state of the first terminal in the AMF network element changes from the connected state to the idle state. When the third timer expires, the processing unit is further configured to not actively initiate the periodic registration (i.e., skip the periodic registration process), but to maintain an expired record of the periodic registration.

In one possible implementation manner of the present application, the communication unit is further configured to receive a paging message from the access network, where the paging message is used to instruct the AMF network element to perform implicit de-registration on the first terminal. For example, the fourth indication is included in the paging message. The fourth indication indicates that the AMF network element is to perform implicit de-registration for the first terminal. Or the fourth indication may be used to indicate paging of the first terminal, which may cause the first terminal to determine that the AMF network element is to perform implicit de-registration for the first terminal.

In a possible implementation manner of the present application, the communication unit is further configured to send a fourth message to the AMF network element if the first condition is met in a case where the third timer expires and an expired record exists. The fourth message is for requesting registration of the first terminal in the first system. The registration type in the fourth message is a mobile registration update. Wherein the first condition comprises any one or more of: and if the first timer does not expire, the first terminal receives the paging message and restores the connection with the first system within the preset time, and the first terminal does not receive the paging message or the first time value. The preset time may be carried in a paging message.

In a possible implementation manner of the present application, the communication unit is further configured to send a fifth message to the AMF network element when the first timer expires or the first terminal receives the paging message but does not respond to the paging message within a preset time. The registration type in the fifth message is initial registration, and the fifth message is used for requesting registration of the first terminal in the first system. For example, the fourth message and the fifth message may be registration request messages.

Illustratively, when the communication device is a chip or a system of chips within the first terminal, the processing unit may be a processor and the communication unit may be a communication interface. For example, the communication interface may be an input/output interface, a pin or a circuit, etc. The processing unit executes the instructions stored by the storage unit to cause the first terminal to implement a communication method as described in the second aspect or any possible implementation manner of the second aspect. The memory unit may be a memory unit (e.g., register, cache, etc.) within the chip, or a memory unit (e.g., read only memory, random access memory, etc.) external to the chip within the first terminal.

In a fifth aspect, the present application provides a computer-readable storage medium, in which a computer program or an instruction is stored, and when the computer program or the instruction runs on a computer, the computer is caused to execute a communication method as described in any one of the possible implementation manners of the first aspect to the first aspect. The computer may be an AMF network element.

In a sixth aspect, embodiments of the present application provide a computer-readable storage medium, in which a computer program or instructions are stored, and when the computer program or instructions are run on a computer, the computer is caused to execute a communication method as described in any one of the possible implementation manners of the second aspect to the second aspect. The computer may be the first terminal.

In a seventh aspect, embodiments of the present application provide a computer program product including instructions that, when executed on a computer, cause the computer to perform the first aspect or one of the communication methods described in the various possible implementations of the first aspect.

In an eighth aspect, embodiments of the present application provide a computer program product comprising instructions that, when executed on a computer, cause the computer to perform the second aspect or one of the communication methods described in the various possible implementations of the second aspect.

In a ninth aspect, embodiments of the present application provide a communication apparatus for implementing various methods in various possible designs of any one of the above first to second aspects. The communication device may be the first terminal, or a device including the first terminal, or a component (e.g., a chip) applied in the first terminal. Alternatively, the communication device may be the AMF network element or a device including the AMF network element, or the communication device may be a component (e.g., a chip) applied in the AMF network element. The communication device comprises modules and units corresponding to the implementation of the method, and the modules and units can be implemented by hardware, software or hardware to execute corresponding software. The hardware or software includes one or more modules or units corresponding to the above functions.

It should be understood that the communication apparatus described in the above ninth aspect may further include: a bus and a memory for storing code and data. Optionally, the at least one processor communication interface and the memory are coupled to each other.

In a tenth aspect, an embodiment of the present application provides a communication apparatus, including: a transceiver and at least one processor. Wherein at least one processor is in communication with the transceiver, the at least one processor executing computer executable instructions or programs stored in the memory when the communication device is run to cause the communication device to perform the method of any of the various possible designs of the first aspect or any of the first aspects as described above. For example, the communication device may be an AMF network element or a chip applied in the AMF network element.

In an eleventh aspect, an embodiment of the present application provides a communication apparatus, including: a transceiver and at least one processor. Wherein at least one processor is in communication with the transceiver, the at least one processor executing computer executable instructions or programs stored in the memory when the communication device is operated to cause the communication device to perform the method of any of the various possible designs of the second aspect or the any of the second aspects as described above. For example, the communication device may be the first terminal or a chip applied in the first terminal.

It should be understood that the communication device described in any of the tenth aspect to the eleventh aspect may further include a memory, and the memory may also be replaced by a storage medium, which is not limited in this application.

In a possible implementation, the memory described in any of the tenth to eleventh aspects may be a memory internal to the communication device, but of course, the memory may also be external to the communication device, but the at least one processor may still execute the computer-executable instructions or programs stored in the memory.

In a twelfth aspect, the present embodiments provide a communication apparatus, where the communication apparatus includes one or more modules, configured to implement the method of any one of the first and second aspects, where the one or more modules may correspond to respective steps in the method of any one of the first and second aspects.

In a thirteenth aspect, embodiments of the present application provide a chip system, where the chip system includes at least one processor, and the processor is configured to read and execute a computer program stored in a memory to perform the method in the first aspect and any possible implementation manner thereof.

Alternatively, the chip system may be a single chip or a chip module composed of a plurality of chips.

Optionally, the chip system further comprises a memory, and the memory and the processor are connected with the memory through a circuit or a wire.

Further optionally, the chip system further comprises a communication interface. The communication interface is used for communicating with other modules outside the chip.

In a fourteenth aspect, an embodiment of the present application provides a chip system, where the chip system includes a processor, and the processor is configured to read and execute a computer program stored in a memory to perform the method in the second aspect and any possible implementation manner thereof.

In a fifteenth aspect, an embodiment of the present application provides a communication system, including: the first terminal and the AMF network element in the first system. Wherein the first terminal is configured to perform the method of the second aspect and any possible implementation manner thereof, and the AMF network element is configured to perform the method of the first aspect and any possible implementation manner thereof.

Any one of the above-provided apparatuses, computer storage media, computer program products, chips, or communication systems is used to execute the above-provided corresponding methods, and therefore, the beneficial effects that can be achieved by the apparatuses, the computer storage media, the computer program products, the chips, or the communication systems can refer to the beneficial effects of the corresponding schemes in the above-provided corresponding methods, and are not described herein again.

Drawings

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

fig. 2 is a system architecture diagram of a 5G network according to an embodiment of the present application;

fig. 3 is a flowchart illustrating a non-3GPP access according to an embodiment of the present application;

fig. 4 is a schematic diagram of a control plane protocol stack according to an embodiment of the present application;

fig. 5 is a flowchart illustrating a communication method according to an embodiment of the present application;

fig. 6a to fig. 6b are schematic flow charts of the communication method under different situations provided by the embodiment of the present application;

fig. 7-10 are schematic diagrams illustrating an embodiment of a communication method according to an embodiment of the present application;

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

fig. 12 is a schematic structural diagram of a communication device according to an embodiment of the present application;

fig. 13 is a schematic structural diagram of a chip according to an embodiment of the present application.

Detailed Description

In the embodiments of the present application, terms such as "first" and "second" are used to distinguish the same or similar items having substantially the same function and action. For example, the first terminal and the second terminal are only used for distinguishing different terminals, and the sequence order thereof is not limited. 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.

It is noted that, in the present application, words such as "exemplary" or "for example" are used to mean exemplary, illustrative, or descriptive. Any embodiment or design described herein as "exemplary" or "e.g.," is not necessarily to be construed as preferred or advantageous over other embodiments or designs. Rather, use of the word "exemplary" or "such as" is intended to present concepts related in a concrete fashion.

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 form a limitation on the technical solution provided in the embodiment of the present application, and as a person of ordinary skill in the art knows that along with the evolution of the network architecture and the appearance of a new service scenario, the technical solution provided in the embodiment of the present application is also applicable to similar technical problems.

In the present application, "at least one" means one or more, "a plurality" means two or more. "and/or" describes the association relationship of the associated objects, indicating that there may be three relationships, e.g., a and/or B, which may indicate: a exists alone, A and B exist simultaneously, and B exists alone, wherein A and B can be singular or plural. The character "/" generally indicates that the preceding and following associated objects are in an "or" relationship. "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.

The steps involved in a communication method provided in the embodiments of the present application are merely examples, and not all the steps are necessarily executed steps, or the content in each information or message is not necessary, and may be increased or decreased as needed in the use process.

In the embodiments of the present application, the same step or message having the same function may be referred to each other between different embodiments.

The system 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 form a limitation on the technical solution provided in the embodiment of the present application, and as a person of ordinary skill in the art knows that along with the evolution of the network architecture and the appearance of a new service scenario, the technical solution provided in the embodiment of the present application is also applicable to similar technical problems. In the embodiment of the present application, the method provided is applied to an LTE system, an NR system, or a fifth Generation mobile communication technology (5th Generation mobile networks, 5th Generation systems, 5th-Generation, 5G) network as an example for description.

Before describing the embodiments of the present application, the terms referred to in the embodiments of the present application will be explained as follows:

1) the mobile reachable timer, the access and mobility management function (AMF) network element or the Mobility Management Entity (MME) is a timer used for determining whether the terminal is reachable, and the running time of the timer is longer than the running time of the periodic registration timer of the terminal. Taking the 5G network as an example, the mobility reachable timer is started when the terminal enters an IDLE state (5GMM-IDLE mode) and is stopped when the N1 NAS signaling connection is established. And if the mobile reachable timer is expired or exceeds the period (expiration), the AMF network element determines that the terminal is not reachable. In general, after the mobile reachable timer expires, the AMF network element starts an implicit de-registration timer (implicit de-registration timer) and stops paging the terminal. If the N1 NAS signaling connection is established, the implicit de-registration timer is stopped. Otherwise, if the hidden deregister timer is expired, the AMF network element implicitly deregisters the terminal.

2) And a periodic registration timer (periodic registration timer), wherein the terminal side is used for determining the periodic registration timer by the terminal. If the terminal accesses the connection system through 3GPP, the AMF network element provides the terminal with the value of the periodic registration timer in the registration procedure. The periodic registration timer is started when the terminal leaves the connected state and is stopped when the terminal enters the connected state or is unregistered. The terminal should perform periodic registration when the periodic registration timer expires.

As shown in fig. 1, fig. 1 is a communication system provided in an embodiment of the present application, where the system includes: an access and mobility management function (AMF) network element 20 in system 1, and an access and mobility management function network element 30 in system 2.

The device 10 is a multi-universal subscriber identity module (MUSIM) card terminal, that is, the device 10 has a plurality of USIM cards. The apparatus 10 includes a plurality of terminals, such as a terminal a corresponding to the USIM card 1 of the apparatus 10 and a terminal b corresponding to the USIM card 2 of the apparatus 10. That is, the device 10 may be a device including a terminal a and a terminal b.

The system 1 is a system in which the terminal a accesses through the USIM card 1 and the access network device 40 in the system 1. The system 2 is a system in which the terminal b accesses the system using the USIM card 2 and the access network device 50 in the system 2.

In the present embodiment, the devices 10 may be distributed in a wireless network, and each device may be static or mobile.

As an example, the system 1 includes not only the access network device 40 to which the terminal a accesses through the USIM card 1, but also a Core Network (CN) device to which the terminal a accesses through the USIM card 1. For example, the core network device may include the AMF network element 20.

As an example, the system 2 includes not only the access network device 50 to which the terminal b accesses through the USIM card 2, but also a Core Network (CN) device to which the terminal b accesses through the USIM card 2. For example, the core network device may include the AMF network element 30.

The device 10 in the embodiment of the present application may support multiple reception or single reception, but the device 10 cannot simultaneously communicate with the system 1 and the system 2. If terminal a in device 10 is currently accessing system 1 and remains connected to system 1, then terminal b leaves system 2 at this time. If the device 10 again wishes to communicate with the system 2 using terminal b, then terminal a may leave the system 1 and terminal b resumes communication with the system 2.

The terminal a leaving the system 1 means that the terminal a disconnects from the network of the system 1, including the connection with the core network and the connection with the access network device, and the like, that is, after the terminal a leaves the system 1, the state of the terminal a in the system 1 will be changed from the connection state to the idle state.

In the following, taking the terminal as a dual USIM card device as an example, the dual USIM card device focuses on two types, i.e., a single receive and single transmit and a dual receive and single transmit. The single sending finger only allows the terminal to send data through one USIM card at the same time, and the single receiving finger only allows the terminal to receive data through one USIM card at the same time. Whether single reception and single transmission or dual reception and single transmission, the terminal is not allowed to simultaneously receive and transmit through two USIMs, i.e., two USIM cards are not allowed to simultaneously communicate with two systems.

The method provided by the embodiment of the application can be applied to the following scenes:

scene 1, taking the device 10 as a mobile phone as an example, if the device 10 is multi-receiving, if the user is using the USIM card 1 in the mobile phone to answer the call of the USIM card 2, and at this time, the mobile phone receives the call of the USIM card 2, if the user selects to answer the call of the USIM card 2, it can be considered that the mobile phone leaves the system accessed by the mobile phone through the USIM card 1, and the mobile phone accesses another system through the USIM card 2.

Scene 2, taking the device 10 as a mobile phone as an example, if the device 10 receives only one call, the device 10 can only receive an incoming call of one USIM card 1 at the same time. If the user is answering the call using the USIM card 1 in the handset, if the user actually wants to receive the incoming call of the USIM card 2, the user can choose to end the answering of the call using the USIM card 1 and leave the system to which the handset is accessed through the USIM card 1, and the handset is accessed to another system and another system through the USIM card 2 to see whether the incoming call of the USIM card 2 is received.

It should be noted that scenario 1 and scenario 2 are only examples of a system in which a terminal leaves a current access, and do not constitute a limitation to the present application.

The communication system shown in fig. 1 in the embodiment of the present application may be applied to a 4G network architecture, a 5G network architecture, and other network architectures appearing in the future, which is not limited in the embodiment of the present application.

Taking the example that the communication system shown in fig. 1 is applicable to a 5G network architecture, a network element or AN entity corresponding to the access network device 40 or the access network device 50 may be a (radio) access network (R) AN device in the 5G network.

If the communication system shown in fig. 1 is applicable to a 4G network architecture, for example, the access and mobility management function element 20 or the access and mobility management function element 30 may be replaced by an element in a packet core (EPC), such as an MME. The network element or entity corresponding to the access network device may be a network device in a 4G network architecture.

As shown in fig. 2, the system 1 may include, in addition to the access and mobility management function network element 20 or the system 2 may include, in addition to the access network device 40 or the access network device 50: a User Plane Function (UPF) network element, a Session Management Function (SMF) network element, a Unified Data Management (UDM) network element, a Policy Control Function (PCF) network element, an Application Function (AF) network element, a Data Network (DN), a Network Slice Selection Function (NSSF) network element, a network capability opening function (NEF) network element, a User Data Repository (UDR), a network, and a network storage repository function (NRF) network element, which are mainly used for discovery of network elements.

The terminal accesses the network through (R) AN equipment, and communicates with the AMF network element through AN N1 interface (N1 for short). The SMF network elements communicate with one or more UPF network elements over an N4 interface (abbreviated N4). The UPF network elements communicate with the DN over an N6 interface (abbreviated N6). And (R) the AN equipment and the AMF network element communicate through AN N2 interface (N2 for short). The (R) AN devices communicate with the UPF network elements over AN N3 interface (abbreviated N3). The control plane network element may also use a service interface for interaction. For example, as shown in fig. 2, the AMF network element, the SMF network element, the UDM network element, or the PCF network element interact using a service interface. For example, the service interface provided by the AMF network element to the outside may be Namf. The service interface externally provided by the SMF network element may be Nsmf. The external serving interface provided by the UDM network element may be Nudm. The service interface provided by the PCF network element may be Npcf. The external service interface provided by the NSSF network element may be NSSF. The service interface provided by the NEF network element to the outside may be Nnef. The service interface provided by the AF network element to the outside may be Naf. The service interface provided by the NRF network element to the outside may be nrrf. It should be understood that the related descriptions of the names of the various service interfaces can refer to 5G system architecture (5G system architecture) diagrams in the prior art, which are not repeated herein.

As shown in fig. 2, in the network architecture, for example, the control plane network element uses a service interface to perform interaction, and of course, the control plane network element may also use the following method to perform communication: the AMF entity communicates with the SMF network element over an N11 interface (abbreviated N11). Any two UPF network elements of the one or more UPF network elements communicate via an N9 interface (abbreviated as N9). The SMF network element communicates with the PCF network element through an N7 interface (N7 for short), and the PCF network element communicates with the AF network element through an N5 interface. Any two AMF network elements communicate with each other through an N14 interface (N14 for short). The SMF network elements communicate with the UDM over an N10 interface (abbreviated N10). The AMF network element communicates with the AUSF through an N12 interface (abbreviated as N12). The AUSF network element communicates with the UDM network element via an N13 interface (abbreviated N13). The AMF network element communicates with the UDM network element via an N8 interface (N8 for short).

It should be noted that fig. 2 is only an exemplary illustration of a UPF network element and an SMF network element. Of course, a plurality of UPF network elements and SMF network elements may be included in the network, for example, the network includes an SMF network element 1 and an SMF network element 2, which is not specifically limited in this embodiment of the present application.

It should be noted that, the (R) AN device, the AMF network element, the SMF network element, the UDM network element, the UPF network element, the PCF network element, and the like in fig. 2 are only names, and the names do not limit the device itself. In the 5G network and other networks in the future, the network elements or entities corresponding to the (R) AN apparatus, the AMF network element, the SMF network element, the UDM network element, the UPF network element, and the PCF network element may also be other names, which is not specifically limited in this embodiment of the present application. For example, the UDM network element may also be replaced by a user home server (HSS) or a User Subscription Database (USD) or a database entity, and the like, which are described in the unified description herein and will not be further described in detail later.

The first TYPE of access in the embodiment of the present application is a third Generation Partnership Project (3 GPP) access, and the included access technology TYPE (RAT TYPE) may be NG-RAN, E-UTRAN, NB-IoT, etc. For example, the terminal 10 may connect to the network using 3GPP access network equipment. The access network device may be a base station. For example, it is called Next Generation base station Node (gNB), evolved Node B (eNB), etc.

The second type of access is non-third Generation Partnership Project (non-3 GPP) access. The non-3GPP Access technology can be an untrusted non-3GPP Access technology, a trusted non-3GPP Access technology, a wired 5G Access Network (W-5 GAN) and the like.

Fig. 3 is a schematic diagram illustrating an architecture of a terminal using a 3GPP access to connect to a network in an embodiment of the present application, and as shown in fig. 3, the terminal may connect to a 5G core network (e.g., an AMF network element in the 5G core network) through a non-3GPP access in addition to the 3GPP access.

In addition, it can be understood that, when the terminal accesses the 5G core network in the manner shown in fig. 3, the network elements in the 5G core network are the same as those in the 5G core network shown in fig. 2. In particular, reference may be made to the network element in fig. 2, which is not described here in detail.

The meaning of each network element involved in the embodiments of the present application is as follows:

and the N3IWF network element is used for realizing that the untrusted non-3GPP access network accesses the 5G core network through the network element.

SMF network elements, session management functions such as session establishment, modification and release, including maintaining tunnels between UPF and AN nodes. IP address assignment and management of the terminal (including optional authorization). And configuring the traffic route in the UPF network element. The session management part of the NAS message terminates.

A terminal, a device allowing a user to access a network service. In the 3GPP standard, the interface between the terminal and the network is a radio interface.

Terminals (terminals) may include a variety of handheld devices with wireless communication capabilities, in-vehicle 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 (hand held), a laptop computer (laptop computer), a cordless phone (cordless phone) or a Wireless Local Loop (WLL) station, a Machine Type Communication (MTC) terminal, a user equipment (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.

It should be understood that the terminal in the embodiment of the present application may be a terminal in multiple vertical industry application fields such as an internet of things terminal device, a port, an intelligent factory, railway traffic, logistics, an unmanned aerial vehicle, and an unmanned vehicle. For example: mobile robots (mobile robots), Automated Guided Vehicles (AGVs), unmanned vehicles, control devices and sensors on trains, control devices and sensors deployed in factories, and the like.

As an example, in the embodiment of the present application, the terminal may also be a wearable device. Wearable equipment can also be called wearable intelligent equipment, is to apply wearing formula technique to carry out intelligent design, develop the general name of the equipment that can wear to daily wearing, for example glasses, gloves, wrist-watch, dress and shoes etc.. A wearable device is a portable device that is worn directly on the body or integrated into the user's clothing or accessories. Wearable equipment is not only a hardware device, realizes powerful function through software support and data interaction, high in the clouds interaction more. The generalized wearable smart device has full functions and large size, and can realize complete or partial functions without depending on a smart phone, for example: smart watches or smart glasses and the like, and only focus on a certain application function, and need to be used in cooperation with other devices such as smart phones, such as various smart bracelets, smart jewelry and the like for physical sign monitoring. The terminal may also be a sensor device applied to a factory.

As shown in fig. 4, fig. 4 provides a control plane protocol stack of a communication system, and as shown in fig. 4, the control plane protocol stack of the terminal sequentially includes, from top to bottom: a non-access stratum (NAS) layer, a Radio Resource Control (RRC) layer, a Packet Data Convergence Protocol (PDCP) layer, a Radio Link Control (RLC) layer, a Medium Access Control (MAC) layer, and a physical layer (PHY) layer. Taking a network device as the gNB as an example, a control plane protocol stack of the gNB sequentially includes from top to bottom: RRC layer, PDCP layer, RLC layer, MAC layer, and PHY layer. In fig. 4, the protocol stack of the AMF network element includes the NAS layer as an example.

RRC connection: a connection established between the terminal and the gNB through an RRC protocol, wherein the RRC protocol is part of a control plane protocol stack. When the terminal is in a connected state, the RRC connection exists between the terminal and the RAN, and if the RRC connection is released, the terminal enters an idle state.

NAS signaling connection: the terminal and the core network element are connected in a one-to-one correspondence manner. For 5G, it can be called N1 NAS signaling connection, referring to a one-to-one connection between the terminal and the AMF network element.

Referring to fig. 1, in order to reduce as much as possible the influence of the terminal a leaving the system 1 currently communicating with the system 1, when the terminal a leaves the system 1, the terminal a needs to negotiate with the system 1, that is, when leaving the system 1, the terminal a indicates to the core network of the system 1 that it is about to leave the system 10, and the core network may determine a processing method of downlink data sent to the terminal a, such as buffering, discarding, or paging the terminal a, according to the indication.

In the prior art, for a terminal that is registered to a network through 3GPP access, the terminal needs to perform periodic registration after leaving the system to which the terminal is accessed and entering an idle state, so that a network (which may refer to a core network (e.g., a 5G core network or a 4G core network) in the system to which the terminal is accessed) knows whether the terminal still needs to connect to the network, and if the terminal is not registered in time, the terminal is deregistered by the network, so as to delete related information of the terminal. Specifically, after the terminal leaves the system 1 and enters an idle state in the system 1, the terminal starts a periodic registration timer, and the value of the periodic registration timer is sent to the terminal by the AMF network element in the registration process. After the terminal enters an idle state, the AMF network element starts a mobile reachable timer, and the value of the mobile reachable timer is greater than that of the periodic registration timer. If the terminal is still in an idle state in the system 1 after the mobile reachable timer expires, the AMF network element considers that the terminal is not reachable, and starts an implicit deregistration timer. And if the terminal is still in an idle state in the system 1 after the implicit de-registration timer expires, the AMF network element implicitly de-registers the terminal. The related information of the terminal may refer to session release, session termination management/access management policy association, association of removed SMF network elements with DNN and PDU session IDs, terminal context release, and the like.

The implicit de-registration in the embodiment of the present application refers to that the network performs de-registration on the terminal locally, but does not notify the terminal.

For a terminal which is accessed and registered to a network through non-3GPP, a non-3GPP deregistration timer is directly started after entering an idle state, and the value of the non-3GPP deregistration timer is sent to the terminal by an AMF network element in the registration process. After the terminal enters an idle state, the AMF network element starts a non-3GPP implicit deregistration timer, and the value of the non-3GPP implicit deregistration timer is greater than that of the non-3GPP deregistration timer. And if the non-3GPP deregistration timer is expired, the terminal implicitly deregisters. And if the non-3GPP implicit de-registration timer expires, the AMF network element executes implicit de-registration.

In the embodiment of the present application, the implicit deregistration timer at the terminal side may also be referred to as a deregistration timer, and the name is not limited in the present application.

As long as the terminal enters the connected state at a certain time, if the certain timer is in progress, the timer is stopped.

If the deregistration is performed, the network does not have the context information, session information, and the like of the terminal. If the terminal needs to recover the previous communication, initial registration and session establishment need to be executed, a large amount of signaling is consumed, and time delay is caused, so that user experience is influenced.

In the prior art, with reference to fig. 1, when a terminal a leaves a current system 1, the terminal a provides a release indication and release assistance information to an AMF network element, where the release indication is used to indicate that the terminal a will leave the current system 1, and the release assistance information includes: terminal a expects the network to trigger a session or service indicated by the arrival of the downstream service and terminal a will leave this serving network for the desired period of time. When the terminal a desires to recover the connection with the current system 10, the terminal a directly sends a service request or a registration request to the AMF network element, and the AMF network element indicates the SMF network element to recover the user plane of the session according to the information provided by the terminal a.

However, in the above solution, since the problem that the terminal a is implicitly deregistered in the system 10 is not considered, that is, if the terminal a is implicitly deregistered by the AMF network element during leaving the system 1, if the terminal a needs to access the system 1 again subsequently, the initial registration and the session re-establishment need to be performed in the system 1 again, and the re-initial registration and the session re-establishment cause a large amount of signaling to cause a delay, thereby affecting the user experience.

Based on this, in order to solve the above problem, in this embodiment of the application, the first terminal performs negotiation with the AMF network element in the first system by using the first information, and when the AMF network element allows the first terminal to leave the first system and does not perform periodic registration after entering the idle state in the first system, the AMF network element may indicate, by using the first indication, to the first terminal that the network side allows the first terminal to perform periodic registration after allowing the state of the first terminal in the first system to be the idle state due to leaving the first system. This facilitates the first terminal determining that a periodic registration may not be initiated upon expiration of the periodic registration timer after leaving the first system. In addition, the first terminal may also determine that the first terminal cannot be implicitly deregistered by the network side for a while even if the first terminal does not initiate the periodic registration when the periodic registration timer expires.

In the embodiment of the present application, a specific structure of an execution main body of a communication method is not particularly limited in the embodiment of the present application, as long as communication can be performed by one communication method according to the embodiment of the present application by running a program recorded with a code of one communication method of the embodiment of the present application. For example, an execution main body of a communication method provided by the embodiment of the present application may be a functional module capable of calling a program and executing the program in the first terminal, or a communication device applied in the first terminal, such as a chip, a system-on-chip, an integrated circuit, and the like. The chip, the chip system, and the integrated circuit may be disposed inside the first terminal, or may be independent from the first terminal, which is not limited in the embodiments of the present application. An execution main body of the communication method provided in the embodiment of the present application may be a functional module capable of calling a program and executing the program in an AMF network element, or a communication device applied to the AMF network element, such as a chip, a chipset, an integrated circuit, and the like, where the chip, the chipset, and the integrated circuit may be disposed inside the AMF network element, or may be independent from the AMF network element, which is not limited in the embodiment of the present application.

As shown in fig. 5, a communication method provided in an embodiment of the present application is illustrated in a manner that a terminal and an AMF network element interact with each other, where the communication method includes:

step 501, the first terminal sends the first information to the AMF network element in the first system. Accordingly, the AMF network element receives the first information from the AMF network element.

For example, the first information is used to request whether to allow the first terminal to not perform periodic registration after entering an idle state in the first system. Optionally, the first information is used to request whether to allow the first terminal to leave the first system and not perform periodic registration after entering an idle state in the first system.

Not performing periodic registration may refer to: after the third timer (periodic registration timer) of the first terminal expires, the first terminal may temporarily not initiate periodic registration with the first system.

The device (for example, the device 10) where the first terminal is located has a plurality of global user identification cards, the first terminal corresponds to a first global user identification card of the plurality of global user identification cards, and the first system is a system to which the first terminal accesses.

Referring to fig. 1, for example, the first terminal may be a terminal a, and the first system may be a system 1.

As an example, a first USIM of a first terminal accesses a first system through a first type. Illustratively, the first type of access may be a 3GPP access.

As an example, the first information may be a message X, or the first information is carried as a field in the message X.

As an example, the first message is a message that is sent to the AMF network element when the first terminal is ready to leave the first system, and then the first message in this embodiment is an uplink NAS message.

As another example, the first information may be a message sent to the AMF network element when the first terminal is registered in the first system, and then the first information is used to indicate that the first terminal requests to register the first terminal in the first system. For example, the first information may be a registration request message.

As yet another example, the first information may be a message sent to the AMF network element after the first terminal leaves the first system. For example, after the first terminal leaves the first system, an uplink NAS message is sent to the AMF network element through the non-3GPP access, where the uplink NAS message is the first information.

Step 502, the AMF network element sends a first indication to the first terminal according to the first information. Accordingly, the first terminal receives the first indication from the AMF network element.

The first indication is used by the first terminal to determine that the first terminal is allowed by the AMF network element to enter the idle state in the first system and then not perform periodic registration, or the first indication is used by the AMF network element to allow the first terminal to enter the idle state in the first system and then not perform periodic registration.

As an example, the first indication is used for the first terminal to determine that the AMF network element allows the first terminal to enter the idle state in the first system due to leaving the first system without performing the periodic registration, or the first indication is used for indicating that the AMF network element allows the first terminal to enter the idle state in the first system due to leaving the first system without performing the periodic registration.

As an example, the first terminal entering the idle state in the first system in the embodiment of the present application may refer to: the state of the first terminal in the first system changes to an idle state due to the first terminal leaving the first system.

As another example, the first terminal entering the idle state in the first system in the embodiment of the present application may refer to: the state of the first terminal in the first system changes to an idle state because the first terminal does not leave the first system.

The following embodiments take an example in which the state of the first terminal in the first system changes to an idle state due to the first terminal leaving the first system.

The first indication in this embodiment of the present application may be a message used for determining that the AMF network element allows the first terminal to enter an idle state in the first system due to leaving the first system, and then not perform periodic registration.

It is to be understood that, in the case where the AMF network element determines, based on the first information, that the first terminal is allowed to leave the first system without periodic registration after entering an idle state in the first system, the first indication is sent to the first terminal.

Before step 502, as a possible implementation manner, the method may further include: and the AMF network element determines whether to allow the first terminal to enter an idle state in the first system because the first terminal leaves the first system and not to perform periodic registration based on the local policy and/or the subscription data of the terminal.

For example, the local policy includes the following information: and if the equipment where the first equipment is located is multi-USIM card equipment, allowing the first terminal to suspend periodic registration. If the equipment where the first terminal is located is not the equipment with multiple USIM cards, the first terminal is not allowed to perform periodic registration, or the first terminal is required to perform periodic registration after entering an idle state in the first system because the first terminal leaves the first system. And if the expected time for the first terminal to leave the first system exceeds a preset value, allowing the first terminal not to perform periodic registration by the AMF network element. If the expected time for the first terminal to leave the first system does not exceed the preset value, the AMF network element does not allow the first terminal to perform the periodic registration, or requires the first terminal to enter an idle state in the first system due to leaving the first system to perform the periodic registration.

For example, the AMF network element may obtain the subscription data of the first terminal from the UDM network element, or the AMF network element has the subscription data of the first terminal. The subscription data of the first terminal includes indication information indicating whether the first terminal is allowed to enter an idle state in the first system due to leaving the first system and is not subjected to periodic registration.

In a possible embodiment, as shown in fig. 5, after step 502, the method provided in this embodiment may further include:

step 503, the first terminal does not perform periodic registration after entering an idle state in the first system according to the first indication. I.e. the process of periodic registration is not performed.

For example, the first terminal does not perform periodic registration after entering an idle state in the first system due to leaving the first system according to the first indication. I.e. the process of periodic registration is not performed.

Since the first terminal may negotiate with the network side at different stages whether to allow the first terminal to leave the first system without performing periodic registration after the state in the first system is idle, the following will be separately described:

example one, in a stage where the first terminal leaves the first system, the first terminal negotiates with the network whether the first terminal does not perform periodic registration after leaving the first system and entering an idle state in the first system.

Since the first terminal is still in the connected state in the first system at the stage that the first terminal is ready to leave the first system, that is, the first terminal is not disconnected from the first system, the first terminal may negotiate with the network whether to allow the first terminal to enter the idle state in the first system without performing periodic registration after leaving the first system.

In this embodiment, the first terminal may implicitly or explicitly indicate that the first terminal requests that the first terminal does not perform periodic registration after entering an idle state in the first system because the first terminal leaves the first system, and the following will be introduced separately:

example 1.1, explicit representation

The first information includes a suspend period registration indication (which may also be referred to as a no period registration indication), or the first information is the suspend period registration indication. The suspend period registration indication indicates that the first terminal desires not to perform period registration after entering an idle state in the first system due to leaving the first system.

In example 1.1, when the first terminal leaves the first system, the first terminal indicates to the network side that the first terminal desires not to perform periodic registration after entering an idle state in the first system due to leaving the first system. Then, when the first information includes the suspend period registration indication, the first information is the message 1. The message 1 is a message indicating that the first terminal will leave the first system, in other words, the message 1 includes a suspend period registration indication. When the first information is the pause period registration indication, the first information is carried in the message 1.

Of course, the message 1 may also include: a release indication and release assistance information. The release indication is used to indicate that the first terminal will leave the first system. The releasing the auxiliary information includes: the first terminal expects the network to trigger a session or service indicated by the arrival of the downstream service, and the first terminal will leave the first system at the expected time. For example, if the AMF network element determines that the expected time that the first terminal will leave the first system is greater than the preset time threshold, the first terminal is allowed to leave the first system and is in an idle state in the first system, and then the first terminal is not periodically registered.

For example, the content of message 1 may be expressed as: { suspend period registration indication, release assistance information }. Alternatively, the first information may be located in the release assistance information. For example, the first information is an indicator "0", and the indicator "0" is located as a field in the release assistance information.

Illustratively, in example 1-1, message 1 may be an upstream NAS message. The uplink NAS message may be a message sent by the terminal to the AMF network element when the terminal leaves the first system. Since the terminal and the first system still maintain the connection state, the uplink NAS message may be sent to the AMF network element.

Then, in example 1.1, the AMF network element may determine, from the suspended periodic registration indication, that the first terminal expects not to perform periodic registration after the first terminal enters an idle state in the first system due to leaving the first system.

Example 1.2, implicit representation

In this example 1.2, the first information comprises a second indication indicating that the first terminal is to leave the first system. Or the first information includes a desired duration for the first terminal to leave the first system, or the first information is a second indication.

The first information is message 1 when the first information includes the second indication or an expected length of time that the first terminal will leave the first system. The message 1 is a message indicating that the first terminal will leave the first system, in other words the message 1 includes a second indication or a desired duration for which the first terminal will leave the first system. The first information is the second indication or the expected time length when the first terminal will leave the first system, and the first information is carried in the message 1.

In example 1.2, if the suspend period registration indication is not included in the first information, but the AMF network element receives the second indication or the expected duration that the first terminal will leave the first system, the AMF network element may also determine whether the first terminal requests that the first terminal is allowed to enter an idle state in the first system without performing period registration after leaving the first system.

In example 1.2, when the terminal leaves the first system, the first terminal indicates to the network side that the first terminal desires not to perform periodic registration after the state in the first system is an idle state because the first terminal leaves the first system. Then message 1 may be used to indicate that the first terminal will leave the first system.

Optionally, the first information may also be indication information indicating that the device where the first terminal is located is a multi-USIM card device, and the AMF network element determines, according to the indication information, that the first terminal is allowed to enter an idle state in the first system due to leaving the first system, and then does not perform periodic registration.

Then, in example 1.2, the AMF network element may determine, according to the second indication or the expected duration, that the first terminal expects the terminal not to perform periodic registration after entering an idle state in the first system because the terminal leaves the first system.

For example, if the AMF network element determines that the first terminal will leave the first system according to the message 1, the first terminal is allowed to leave the first system and enter an idle state in the first system, and then does not perform periodic registration. In this case the second indication or the expected duration of time the first terminal will leave the first system may not be included in message 1.

In example 1.2, the AMF network element determines whether to allow the first terminal to enter an idle state in the first system without periodic registration after leaving the first system based on the desired duration and/or the periodic registration update timer value.

As a possible embodiment, combining example 1.1 and example 1.2, the first indication may be carried as one field in message 2. Alternatively, the first indication is message 2. This message 2 may be a downstream NAS message. For example, the first indication, indicator 1, indicates that periodic registration is not allowed. For example, the first indication, indicator 2, indicates that periodic registration is not allowed.

As an embodiment of the present application, a method provided in an embodiment of the present application may further include: the AMF network element sends the first time value to the first terminal. The first time value is used to indicate a duration of a first timer for implicit deregistration of the first terminal in the first system, that is, the first time value is an operation duration of the first timer at the first terminal side. The first timer refers to a timer started by the first terminal after the first terminal enters an idle state in the first system due to leaving the first system. The first terminal performs implicit de-registration when the first timer expires. For example, the first timer may be an implicit de-registration timer on the first terminal side.

In one example, the first time value and the first indication are carried in the same message, such as message 2. For another example, the first time value and the first indication are carried in different messages.

As another embodiment of the present application, the first indication may also be a first time value, which may enable the AMF network element to implicitly indicate to the first terminal that the network side allows the first terminal to enter an idle state in the first system due to leaving the first system, and then not perform periodic registration.

In the above solution, the AMF network element provides the first time value to the first terminal, and the first terminal may determine whether the first terminal has been implicitly deregistered by the network side based on the received first time value, so that the AMF network element can be more quickly restored to the connected state in different ways when returning to the first system. For example, the first terminal determines that the network side (e.g., AMF network element) has implicitly deregistered the first terminal, then an initial registration procedure is performed to recover to a connected state in the first system. For example, if the first terminal determines that the network side has not implicitly registered the first terminal, the registration type is indicated as mobile registration update when the registration procedure is executed, so as to recover to a connected state in the first system.

Since the content of the first information is different, the content of the first indication, the actions of the AMF network element and the terminal are different, and the following description will be separately described with reference to fig. 6a to 6 b:

as shown in fig. 6a, step 501 in the embodiment of the present application may be implemented by the following step 601a or step 601 b:

step 601a, the first terminal sends first information including a suspend period registration instruction to the AMF network element, and correspondingly, the AMF network element receives the first information including the suspend period registration instruction from the first terminal.

It is to be understood that in the scheme shown in step 601a, the first terminal sends a suspend period registration indication to the AMF network element. And after receiving the pause period registration instruction, the AMF network element determines whether to allow the first terminal not to perform the period registration or not based on a local policy and/or subscription data of the first terminal.

Step 601b, the first terminal sends the first information to the AMF network element, and correspondingly, the AMF network element receives the first information from the first terminal. The first information comprises a desired time length or a second indication of the first terminal leaving the first system.

It can be understood that, in the scheme shown in step 601b, after receiving the uplink NAS message from the first terminal, indicating that the first terminal leaves the first system, the AMF network element determines, based on the local policy and/or the subscription data of the first terminal, whether to allow the first terminal to enter an idle state in the first system because the first terminal leaves the first system, and then does not perform periodic registration.

Step 602a is synchronous with step 502, and is not described herein again.

It should be noted that, in the scenario shown in step 601b or step 601a, if the AMF network element allows the first terminal not to perform periodic registration, the AMF network element further sends the first time value to the first terminal. Correspondingly, as shown in fig. 6a, the method provided in the embodiment of the present application may further include:

step 602b, the AMF network element sends the first time value to the first terminal, and correspondingly, the first terminal receives the first time value from the AMF network element. Wherein the first timer duration is used for indicating that the first terminal is implicitly unregistered in the first system.

It should be noted that, if the AMF network element does not allow the first terminal not to perform the periodic registration, the process of sending the first time value to the first terminal by the AMF network element may be omitted, that is, the AMF network element does not send the first time value to the first terminal.

In this case, if the AMF network element sends the first time value to the first terminal and does not send the first indication to the first terminal, the first terminal may also determine that the AMF network element allows the first terminal to enter an idle state in the first system due to leaving the first system and then does not perform periodic registration.

It is worth noting that step 602b may be omitted when the first indication and the first time value are carried in the same message. The first indication and the first time value are sent to the first terminal through different messages.

Accordingly, as shown in fig. 6a, the step 503 can be implemented as follows:

step 603, the first terminal determines not to perform periodic registration until the first timer expires.

Because the time value of the first timer is the first time value and is configured by the AMF network element, the first terminal may determine that the network side may not implicitly register the first terminal temporarily before the expiration of the first timer even if the first terminal does not perform periodic registration. In other words, the first terminal determines that periodic registration is needed after the first timer expires, so as to prevent implicit de-registration by the network side.

It should be noted that the first terminal may also perform periodic registration before the first timer expires, so as to recover the connection with the first system. The first timer is a maximum duration of time during which the first terminal can not perform periodic registration after entering an idle state in the first system due to leaving the first system, wherein the duration is provided by the AMF network element to the first terminal.

Fig. 6a above describes that, for example, the AMF network element provides the first time value to the first terminal whether the first information includes the suspend period registration indication, and of course, when the first terminal sends the first information to the AMF network element in either step 601a or step 601b, the AMF network element may not provide the first time value to the first terminal.

It can be understood that, in one aspect, if the first terminal sends the first information to the AMF network element in step 601a, the AMF network element allows the first terminal not to perform periodic registration after entering the idle state in the first system because the first terminal leaves the first system as a default as long as the first terminal sends the suspend periodic registration instruction.

On the other hand, if the first terminal sends the first information to the AMF network element in step 601b, that is, the first information includes the expected duration or the second indication that the first terminal will leave the first system, but does not include the suspend period registration indication, the AMF network element does not send the first time value to the first terminal.

It will be appreciated that the default AMF network element now allows the first terminal to enter an idle state in the first system without periodic registration because the first terminal leaves the first system. As long as the AMF network element receives the uplink NAS message from the first terminal, which indicates that the first terminal leaves the first system, even if the uplink NAS message does not carry the suspend period registration indication, the AMF network element allows the first terminal to leave the first system and not perform the period registration after entering the idle state in the first system.

It is to be understood that, in the embodiments shown in fig. 6a to 6b, whether the AMF network element sends the first time value to the first terminal or not, if the first indication is message 2, then the message 2 may further include: indicating the information. The indication information indicates that the first terminal is allowed to enter an idle state in the first system without periodic registration due to leaving the first system. Thus, the first terminal can determine that the AMF network element allows the first terminal to leave the first system and not perform periodic registration after entering an idle state in the first system according to the indication information. Of course, the message 2 may not include the indication information.

However, there is a difference in the way in which the AMF network element provides the first terminal with the first time value, so that the first terminal and the AMF network element perform implicit de-registration, which will be described below with reference to fig. 6a or fig. 6b, respectively. Fig. 6a mainly aims at a manner that the first terminal and the AMF network element perform implicit de-registration when the AMF network element provides the first time value, and fig. 6b mainly aims at a manner that the first terminal and the AMF network element perform implicit de-registration when the AMF network element does not provide the first time value:

in a possible embodiment, the method provided in this embodiment of the present application may further include, after step 603:

step 604a, at the second time, the first terminal starts the third timer and the first timer. The value of the first timer is a first time value. The second time is a time when the first terminal changes from the connected state to the idle state. In other words, the second time instant is the time instant at which the first terminal determines that the first terminal transits from the connected state to the idle state in the first system due to leaving the first system.

Illustratively, the third timer is a periodic registration timer and the first timer is an implicit de-registration timer, for example.

Step 605a, when the third timer expires, the first terminal does not actively initiate the periodic registration, but stores the expired record. The expiration record indicates that the third timer has expired.

Step 606a, when the first timer expires, the first terminal performs implicit de-registration in the first system.

For the procedure of performing the implicit de-registration by the first terminal, reference may be made to the description in the prior art, and details are not described herein.

As shown in fig. 6a, in a possible embodiment, the method provided in this embodiment of the present application may further include, after step 603:

step 607a, at the first time, the AMF network element does not start the mobile reachable timer (i.e. the AMF network element skips the start of the mobile reachable timer).

The first moment is the moment when the connection state of the terminal in the AMF network element is changed from the connection state to the idle state.

It can be understood that, of course, the AMF network element may start the mobile reachable timer, and after the mobile reachable timer expires, the terminal is still in an idle state, and the AMF network element considers that the terminal is not reachable. In this case, although the AMF network element starts the mobile reachable timer, the second timer is not started when the mobile reachable timer expires.

step 608a, at the first time, the AMF network element starts a second timer, and a value of the second timer is greater than the first time value.

Step 609a, when the second timer expires, if the connection state of the terminal in the AMF network element is an idle state, the AMF network element performs implicit de-registration on the terminal.

It is to be understood that the first time is a time when the terminal from the perspective of the AMF network element changes from a connected state to an idle state in the AMF network element. The second time in step 604a is the time when the terminal changes from the connected state to the idle state in the AMF network element, which is obtained from the terminal perspective. The first time and the second time may be the same or different, and this is not limited in this embodiment of the application.

With reference to fig. 6a, before the sending, by the method provided in this embodiment of the present application, the first indication to the first terminal, the method may further include: and the AMF network element determines a first time value according to one or more of a local policy, subscription data of the first terminal, expected leaving time provided by the first terminal and a mobile model.

In a possible embodiment, if the AMF network element does not send the first time value to the first terminal in the first example, as shown in fig. 6a, the method provided in this embodiment further includes:

step 610a, after the first terminal enters an idle state in the first system, the AMF network element sends a paging request to the access network, and the access network receives the paging request from the AMF network element.

The paging request is for requesting the access network to page the first terminal and indicating in a paging message that the AMF network element is to perform implicit de-registration for the first terminal.

For example, the paging request includes field 1 and field 2. Field 1 is used to request the access network to page the first terminal. The field 2 is used to indicate to the access network that the AMF network element is to perform implicit de-registration for the first terminal in a paging message paging the first terminal. Or the first message comprises a field 1, wherein the field 1 is used for requesting the access network to page the first terminal, and is used for indicating that the access network indicates that the AMF network element is to perform implicit deregistration on the first terminal in the paging message for paging the first terminal.

Optionally, the paging request includes first indication information, where the first indication information is used to indicate that the AMF network element is to perform implicit de-registration for the first terminal.

By implicit de-registration is meant that after a period of time (e.g., a preset time), the AMF network element will perform implicit de-registration for the first terminal. The embodiment of the application does not limit the time when the AMF network element sends the paging request and the time interval for executing the implicit de-registration. Optionally, the paging request may further include a time period, which is used for making the first terminal explicitly specify a time for the network side to perform implicit de-registration on the first terminal.

Step 610a may be implemented by the AMF network element sending a paging request to the access network (e.g., RAN), which then pages the terminal. The first indication information is included in a paging request sent by the AMF network element to the RAN and a paging message sent by the RAN to the first terminal.

Step 611a, the access network in the first system sends a paging message to the first terminal. Accordingly, the first terminal receives a paging message from the access network. The paging message includes a paging cause indicating that the AMF network element is to implicitly de-register the first terminal.

In one embodiment of the present application, if the AMF network element sends the first time value to the terminal, steps 610a to 611a may be omitted.

In another embodiment of the present application, if the AMF network element sends the first time value to the first terminal, the AMF network element may still perform steps 610a to 611 a. This is because the first time value may be long, and the AMF network element, which is caused by other factors before reaching the first time value, may want to implicitly register the first terminal in advance, and thus inform the first terminal that implicit deregistration is about to occur. Thus, if the first terminal wants to continue the traffic transmission with the first system, the first terminal can resume the connection with the first system in advance according to the paging request without waiting until the first time value is over. In another aspect, it is facilitated for the first terminal to determine that the AMF network element implicitly deregisters the first terminal in advance.

In a possible embodiment, if the AMF network element determines that the first terminal is no longer allowed to enter the idle state in the first system due to leaving the first system, the method provided in this embodiment of the present application may further include: and the AMF network element sends a fourth message to the first terminal. Accordingly, the first terminal receives the fourth message from the AMF network element. The fourth message includes the third information. The third information indicates that the first terminal is not allowed to enter an idle state in the first system due to leaving the first system and then does not perform periodic registration. Or the third information indicates that the first terminal is required to enter an idle state in the first system due to leaving the first system and then perform periodic registration. For example, the third information may be a pause period registration indication.

When the first terminal has not left the first system, the AMF network element determines that the first terminal is no longer allowed to perform periodic registration after entering an idle state in the first system due to leaving the first system, and then the third message may configure an update command message for the UE.

When the first terminal leaves the first system, the AMF network element determines that the first terminal is no longer allowed to enter an idle state in the first system due to leaving the first system and then does not perform periodic registration, and the AMF network element may send the third information to the first terminal through the paging server or the network element in the second system. Specifically, the AMF network element may send the third information to the first terminal before the first terminal or the AMF network element performs implicit de-registration on the first terminal.

In a possible embodiment, after the first terminal leaves the first system through the first global subscriber identity card, the second terminal can communicate with the second system through the second global subscriber identity card, and then the second terminal can determine to leave the second system in the following way.

Determining to leave the second system based on one or more of the following conditions:

1) the service of the second terminal in the second system is completed.

2) The first terminal receives a paging message in which service-related information of MT data triggering paging may be indicated. The paging message is used to page the first terminal.

3) The first terminal receives a message (e.g., a paging message) that an AMF network element is about to implicitly de-register the first terminal in the first system.

4) The first terminal receives the first time value and decides to temporarily resume the connection with the first system before implicit deregistration so as not to be deregistered by the AMF network element in the first system.

In this embodiment of the application, after the second terminal leaves the second system, the first terminal may execute a recovery procedure of the first system, and if the first terminal determines that the AMF network element does not perform implicit deregistration on the first terminal in the first system, or the first terminal does not perform implicit deregistration on the first terminal in the first system, the first terminal may pass the following case 1. If the first terminal has been implicitly unregistered in the first system, the first terminal may resume the connection with the first system through case 2.

As an alternative embodiment, as shown in fig. 6a, the method provided in the embodiment of the present application may further include:

step 612, the first terminal sends the initial NAS message to the AMF network element. Accordingly, the AMF network element receives the initial NAS message from the terminal. The registration update message is used to request registration of the first terminal in the first system.

The initial NAS message is a first message sent by the first terminal in an idle state in the first system to the AMF network element, and is used to establish an NAS signaling connection from the first terminal to the AMF network element. The initial NAS message generally includes a registration request message, a service request message, and the like. Specifically, the initial NAS message here is divided into the following scenarios:

case 1, the initial NAS message may be a service request message or a registration request message.

Scenario 1.1), the initial NAS message may be a service request message or a registration request message if the periodic registration timer has not expired. Considering the main purpose of the new flow of service requests: the state of the first terminal is changed from the idle state to the connected state, and therefore, the first terminal generally selects to send the service request message. Of course, alternatively, the first terminal may choose to send the registration request message and indicate the registration type as mobile registration update in the registration request message.

Scenario 1.2), if the periodic registration timer expires, that is, there is an expired record, and any one of the following conditions a to c is satisfied, the initial NAS message is a registration request message, and the registration type in the registration request message is indicated as periodic registration update.

Case a, the first terminal receives the first time value, but the implicit de-registration timer at the first terminal side has not expired.

And b, the first terminal receives a paging message with an indication of coming implicit de-registration, and starts to execute a recovery process within a preset time, wherein in this case, a specific time value is determined by implementation, and the embodiment of the application is not limited.

Case c, the first terminal does not receive the first time value or a paging message with an indication of an impending implicit de-registration. In this case, the first terminal is in a registration state, and the first terminal may send the service request message, but actually expires, and the first terminal needs to negotiate some information with the network side through a registration procedure, so that sending the registration request message is more reasonable.

For the above cases b) or c), the first terminal may not know whether the network has unregistered the first terminal, and may receive a registration reject message or a service reject message after sending the registration request message or the service request message, and indicate that the first terminal has been implicitly unregistered.

Case 2, the initial NAS message is a registration request message. Wherein, the registration request message carries the registration type as initial registration.

It is understood that the first terminal performs an initial registration procedure under the following scenario:

1) receiving a first time value, and expiring an implicit de-registration timer; or 2) receiving a paging message indicating that implicit deregistration is to be performed, and sending, by the first terminal, a message for recovering connection to the AMF network element after a preset time, where in this case, the specific time value is determined by implementation, which is not limited in the embodiment of the present application.

As shown in fig. 6b, as an alternative embodiment, the method provided in this embodiment of the present application may further include, after step 603:

step 604b, at the first moment, the AMF network element starts a timer.

The timer is used for recording the duration of the first terminal entering an idle state in the first system due to leaving the first system.

Step 605b, when the time length for the first terminal to leave the first system and enter the idle state is greater than or equal to the second time value, the AMF network element performs implicit de-registration on the first terminal.

Specifically, according to the policy of the operator and/or the local configuration of the AMF network element, the AMF network element performs implicit deregistration on a plurality of terminals (including the first terminal in the embodiment of the present application) that enter an idle state in the first system due to leaving the first system at a specific time. At this time, the AMF network element determines whether to implicitly deregister the first terminal based on the off-network timer. For example, taking a plurality of terminals including terminal a, terminal b, and terminal c as an example, if the duration that terminal a and terminal b enter the idle state due to leaving the first system is greater than or equal to the second time value, the AMF network element performs implicit de-registration on terminal a and terminal b.

Illustratively, the AMF network element periodically and implicitly registers the terminal which is away from the network and has more than two periodic registration time values. The embodiment of the present application does not limit the time when the AMF network element performs implicit de-registration on the plurality of terminals z entering the idle state in the first system due to leaving the first system and how to refer to the off-network timer.

and step 606b, at the second moment, the first terminal starts a third timer.

Step 607b, when the third timer expires, the first terminal does not actively initiate the periodic registration, but stores the expired record. The expiration record is used to record the expiration of the third timer.

Steps 608b to 610b, and synchronization steps 610a to 612, which are not described herein again.

It should be noted that the difference between fig. 6a and fig. 6b is: in fig. 6a, when the first terminal receives the first time value, the action of the first terminal and the action of the AMF network element performing implicit de-registration on the first terminal are shown. Fig. 6b shows an action of the AMF network element performing implicit deregistration to the first terminal and an action of the terminal under the condition that the AMF network element does not send the first time value to the first terminal.

Example two, in a registration stage of the first terminal in the first system, it is negotiated with the network whether the first terminal does not perform periodic registration after entering an idle state in the first system because the first terminal leaves the first system.

Then, in example two, the message 1 may be a registration request message, and the message 2 may be a registration accept message.

In this example two, the first information is a registration request message, and then a pause period registration indication is included in the registration request message. The first information is carried in the registration request message, and then the first information may be a suspend period registration indication.

In this second example, a first indication is carried in the message 2, where the first indication is an indication for indicating that the first terminal is allowed to enter an idle state in the first system without periodic registration because the first terminal leaves the first system. Such as a pause period registration indication.

In example two, as an embodiment of the present application, a method provided in the embodiment of the present application may further include: the AMF network element sends the first time value to the first terminal.

As another embodiment of the present application, the first indication may also be a first time value. Therefore, the AMF network element can implicitly indicate the network side to the first terminal to allow the first terminal to enter an idle state in the first system without periodic registration due to leaving the first system.

The first example and the second example may be combined, that is, the first terminal registers in the first system, and then performs the step of leaving the first system after registering.

If the AMF network element does not send the first time value to the first terminal during the registration phase, the AMF network element may provide the first time value to the first terminal when the first terminal leaves the first system.

If the AMF network element provides the first time value to the first terminal during the registration phase, the AMF network element may not send the first time value when the first terminal leaves the first system. Alternatively, the AMF network element sends the first time value to the first terminal even during the registration phase. When the first terminal leaves the first system, the AMF network element may also send a first time value to the first terminal again, and the first time values sent by the AMF network element in the two stages may be different or the same, which is not limited in this embodiment of the present application. For example, if the first time values sent by the AMF network element in the two phases may be different, the first terminal may be subject to the first time value sent by the AMF network element to the first terminal when the first terminal leaves the first system.

Example three, after the first terminal leaves the first system, it is negotiated with the network whether the first terminal does not perform periodic registration after entering an idle state in the first system because the first terminal leaves the first system.

In example three, the first information is a message sent to the AMF network element after the first terminal leaves the first system. In one aspect, the first information is message 1 (e.g., the uplink NAS message, or a message dedicated to negotiate whether to allow the suspend period registration), and then the suspend period registration indication is included in the uplink NAS message. The first information is carried in the uplink NAS message, and then the first information may be a suspend period registration indication.

The first indication is an indication indicating that the first terminal is allowed to suspend periodic registration. For example, the indication for indicating that the first terminal is allowed to suspend period registration is a suspend period registration indication.

Accordingly, step 501 may be implemented by way of the following modes 1 and 2:

in the mode 1, the first terminal sends first information including a pause period registration instruction to the AMF network element by using the second type access. Accordingly, the AMF network element receives the first information from the first terminal through the second type access.

For example, the second type of access is non-3GPP access technology. For example, the first terminal sends the first information to the N3IWF in the first system, so that the N3IWF forwards the first information to the AMF network element.

In mode 1 of example three, as an embodiment of the present application, a method provided in the embodiment of the present application may further include: and the AMF network element sends the first time value to the first terminal by using the second type access.

As another embodiment of the present application, the first indication may also be a first time value, which may enable the AMF network element to implicitly indicate to the first terminal that the network side allows it to enter an idle state in the first system without periodic registration due to leaving the first system.

Accordingly, the step 502 can be implemented as follows: and the AMF network element sends the first indication to the first terminal through the second type access. Accordingly, the first terminal receives the first indication from the AMF network element through the network element in the second system.

For example, after the second terminal establishes a connection with the second system, the first terminal may register with the first system again through the user plane of the second terminal in the second system, so that the first terminal realizes access to the first system through the second type. Thus, in case the second terminal has a communication connection with the second system and the first terminal leaves the first system, the first terminal may send the first information to the first terminal using the second type of access.

Of course, the first terminal may also register in the first system with the second type of access without borrowing the user plane of the second terminal.

In mode 2, the first terminal sends first information including a suspend period registration indication to the AMF network element by using the first network element or the device in the first system. Accordingly, the AMF network element receives the first information from the first terminal from the network element in the first system.

For example, the first network element or device may be a paging server.

It is worth mentioning that there is a paging server in the first system, which can be understood as a network element or device. When the first terminal leaves the first system and the connection state in the first system is an idle state, the core network and the first terminal can send signaling to the paging server at the user plane of the second system through the second terminal. For example, when the AMF network element determines that there is downlink data to page the first terminal, the AMF network element may send the downlink data to the paging server. And the paging server sends the downlink data to the first terminal on the user plane of the second system through the second terminal.

As an embodiment of the present application, a method provided in an embodiment of the present application may further include: the AMF network element sends the first time value to the terminal by using the first network element or the device.

As another embodiment of the present application, the first indication may also be a first time value, which may enable the AMF network element to implicitly indicate to the first terminal that the network side allows the first terminal to enter an idle state in the first system without performing periodic registration due to leaving the first system.

Accordingly, the step 502 can be implemented as follows: and the AMF network element sends a first indication to the first terminal through the paging server. Accordingly, the first terminal receives the first indication from the AMF network element through the paging server.

The above describes, with reference to the first to third examples, a procedure in which the first terminal and the network side negotiate that periodic registration is not performed after the connection state in the first system is an idle state due to leaving the first system, from different stages. In example two and example three, both the way in which the first terminal performs implicit de-registration in the first system and the way in which the AMF network element performs implicit de-registration on the first terminal in the first system may refer to descriptions in fig. 6a to fig. 6b in example one, and are not described again here.

In example three, the above steps 610a and 611a may be replaced by: and after the first terminal is in an idle state in the first system, the AMF network element sends a second message to the first terminal through the second type access or the first network element, and correspondingly, the first terminal receives the second message from the AMF network element through the second type access or the first network element. Wherein the second message is used for indicating that the AMF network element is about to perform implicit de-registration on the first terminal. The second message may be an NAS notification message, or may also be a notification message sent by the paging server to the first terminal, which is not limited in this embodiment of the present application.

In the above embodiment, taking an example that the AMF network element allows the first terminal not to perform the periodic registration after entering the idle state, if the AMF network element determines that the first terminal is not allowed to perform the periodic registration after entering the idle state, step 502 may be replaced by the following method: and the AMF network element sends a fifth instruction to the first terminal according to the first information, and correspondingly, the terminal receives the fifth instruction from the AMF network element. The fifth indication is for the first terminal to determine not to allow the first terminal to enter an idle state in the first system due to leaving the first system without periodic registration. The first terminal may determine to perform the periodic registration after the first system and before the periodic registration timer expires according to the fifth indication. Or deregister or implicitly deregister when leaving the first system.

As shown in fig. 7, a plurality of USIM cards include a USIM card 1 and a USIM card 2, where the USIM card 1 and the USIM card 2 belong to the same device, that is, the device is a device having multiple USIM cards, and the device having multiple USIM cards is a device including a terminal 1 and a terminal 2; the system 1 is a system in which the terminal 1 accesses through the USIM card 1. The system 2 is an example in which the terminal 2 accesses the system through the USIM card 2, and the AMF network element 1 is an example in the system 1, and describes a specific embodiment of a communication method provided in the embodiment of the present application when the terminal 1 is ready to leave the system 1, where the method includes:

step 701, the terminal 1 sends an uplink NAS message to the AMF network element 1. Accordingly, the AMF network element 1 receives the uplink NAS message from the terminal 1. The upstream NAS message is used to indicate that the terminal 1 is about to leave the system 1.

In a possible implementation manner, the uplink NAS message includes a suspend period registration indication, where the suspend period registration indication is used to indicate that the terminal 1 expects that the terminal 1 does not perform periodic registration after entering an idle state in the system 1 due to the terminal 1 leaving the system 1.

After the terminal 1 sends the uplink NAS message to the AMF network element 1, there are two possible ways to release the RRC connection, as shown in step 702 and step 703. Step 702 is a procedure of locally releasing RRC connection. Step 703 is a procedure for releasing the RRC connection non-locally.

Wherein step 702 comprises: step 702a to step 702 d.

Step 702a, the terminal 1 releases the RRC connection.

It is to be understood that terminal 1 and RAN1 do not interact during the release of the RRC connection by terminal 1.

Step 702b, after receiving the uplink NAS message, the AMF network element 1 sends a UE context release command message to the RAN 1. Accordingly, the RAN1 receives the UE context release order message from the AMF network element 1.

Wherein the UE context release order message is used to instruct the RAN1 to release the logical connection between the RAN1 and the AMF1 related to the terminal 1.

In step 702c, after receiving the UE context release command, the RAN1 locally releases the RRC connection if the RAN1 still has the RRC connection locally.

Step 702d, after releasing the RRC connection, the RAN1 sends a UE context release completion message to the AMF network element 1. Correspondingly, the AMF network element receives the UE context release complete message from the terminal 1. The UE context release complete message is used to indicate that the connection release related to the terminal 1 is completed.

Step 703, the AMF network element 1 sends the downlink NAS message to the terminal 1 through the RAN 1. Accordingly, the terminal 1 receives the downstream NAS message from the AMF network element 1 through the RAN 1.

Optionally, the downlink NAS message includes the first time value. The downlink NAS message is used to respond to the uplink NAS message sent by the terminal 1. The first time value is the running time of the implicit deregistration timer of the terminal 1. When the implicit deregistration timer expires, the terminal 1 performs implicit deregistration. The AMF network element 1 may determine the first time value based on one or more of a local policy, subscription data, and information provided by the terminal 1.

As an example, step 703 may be implemented by: the AMF network element 1 sends message a to the RAN 1. The message a includes, in addition to the downlink NAS message, an indication of the release of the terminal context. RAN1 sends an RRC release indication to terminal 1 simultaneously with or after sending the downlink NAS to terminal 1.

Step 701 may include a pause period registration indication and step 703 may include a first time value. There are four alternative schemes:

scheme 1), the uplink NAS message includes a suspend period registration instruction, and the downlink NAS message includes a first time value when the AMF network element 1 allows the terminal 1 to enter an idle state in the system 1 without performing the period registration after leaving the system 1. Under the scheme, it can be understood that the terminal 1 sends a suspend period registration instruction, and after receiving the suspend period registration instruction, the AMF network element 1 determines whether to allow the terminal 1 to leave the system 1 and not perform the periodic registration after the connection state in the system 1 is an idle state based on a local policy and/or subscription data of the terminal 1. If the time value is allowed, the first time value is included in the downlink NAS message. And if not, the first time value is not contained in the downlink NAS message.

Scheme 2) and the uplink NAS message include a suspend period registration instruction, and the downlink NAS message does not include the first time value when the AMF network element 1 allows the terminal 1 to leave the system 1 and does not perform the period registration after the connection state in the system 1 is the idle state. In this scheme, by default, as long as the terminal 1 sends the suspend period registration instruction, the AMF network element 1 allows the terminal 1 to leave the system 1 and enter an idle state in the system 1, and then does not perform the period registration.

Scheme 3), the uplink NAS message does not include a suspend period registration instruction, and the downlink NAS message includes the first time value when the AMF network element 1 does not perform the periodic registration after allowing the terminal 1 to enter an idle state in the system 1 because the terminal leaves the system 1. Under this scheme, it can be understood that, after the AMF network element 1 receives the uplink NAS message from the terminal 1 indicating that the terminal 1 leaves the system 1, the AMF network element 1 determines whether to allow the terminal 1 to enter an idle state in the system 1 due to leaving the system 1 based on a local policy and/or subscription data of the terminal 1, and then does not perform periodic registration. And if the time value is allowed to be allowed, the downlink NAS message contains the first time value. And if not, the first time value is not contained in the downlink NAS message.

Scheme 4), the uplink NAS message does not include the suspend period registration indication, and the downlink NAS message does not include the first time value. In this scheme, the default AMF network element 1 allows the terminal 1 to enter the idle state in the system 1 without performing the periodic registration after leaving the system 1, and as long as the uplink NAS message from the terminal 1 indicating that the terminal 1 leaves the system 1 is received, the terminal 1 may not perform the periodic registration after entering the idle state in the system 1.

For the scheme 1) and the scheme 3), the terminal 1 and the AMF network element 1 do not perform periodic registration as follows:

A) and after the state of the terminal 1 in the AMF network element 1 enters an idle state from a connection state, the AMF network element 1 does not start a mobile reachable timer, and starts an implicit deregistration timer.

The value of the implicit de-registration timer is greater than the first time value sent by the AMF network element 1 to the terminal 1. If the terminal 1 is still in an idle state when the implicit de-registration timer expires, the AMF network element 1 performs implicit de-registration on the terminal 1.

B) And after the state of the terminal 1 in the AMF network element 1 enters an idle state from a connection state, the terminal 1 starts a periodic registration timer and simultaneously starts an implicit de-registration timer. When the periodic registration timer expires, the terminal 1 does not actively initiate periodic registration, but stores an expired record. The value of the implicit de-registration timer at the terminal 1 side is the first time value, and when the implicit de-registration timer expires, the terminal 1 executes implicit de-registration.

For the scheme 2) and the scheme 4), the terminal 1 and the AMF network element 1 do not perform periodic registration as follows:

A) after the state of the terminal 1 in the AMF network element 1 enters an idle state from a connected state, the AMF network element 1 does not start a mobile reachable timer and an implicit deregistration timer, and starts an off-network timer.

Wherein, the off-network timer is used for recording the time that the terminal 1 is in an idle state because of leaving the system 1. The AMF network element uniformly executes implicit de-registration of one or more terminals (including the terminal 1) which are off-network at a specific time according to the policy of an operator and/or the local configuration of the AMF network element. The implicit de-registration determines whether to implicitly de-register the terminal 1 based on an off-network timer. For example, the AMF network element 1 periodically and implicitly registers the terminal which is away from the network for more than two periods of registration time values.

B) And after the state of the terminal 1 in the AMF network element 1 enters an idle state from a connection state, the terminal 1 starts a periodic registration timer. When the periodic registration timer expires, the terminal 1 does not actively initiate periodic registration, but stores an expired record.

Step 704, the AMF network element 1 sends a session update request to the SMF network element 1 according to the information and/or the local policy provided by the terminal 1, and correspondingly, the SMF network element 1 receives the session update request from the AMF network element 1. The session update request is used to instruct the SMF network element 1 to release the user plane of the relevant session, and how to process the downlink data during the process of leaving the current system by the terminal 1, such as discarding the downlink data, buffering the downlink data, paging the terminal 1, and so on.

Step 705, based on the information provided by the AMF network element 1, obtaining policy information, subscription data, local configuration, etc. from the PCF network element 1, the SMF network element determines how to handle the session and notify the relevant UPF network element.

Step 706, after the SMF network element 1 updates the session, it sends a session update response to the AMF network element 1.

The steps 704-706 and 707 are not in sequence.

In step 707, after the terminal 1 leaves the system 1, the terminal 2 executes the recovery flow of the system 2.

The recovery process executed by the terminal 2 in the system 2 may refer to the recovery process executed by the terminal 1 in the system 1, and is not described herein again. The recovery procedure performed by the terminal 1, i.e. step 711-715 or step 716-717, will be described below from the perspective of the system 1. After the terminal 2 executes the recovery flow of the system 2, the terminal 2 is in a connected state in the system 2, and the terminal 1 is in an idle state in the system 1.

Step 708, the AMF network element 1RAN1 sends a first message. Accordingly, the RAN1 receives the first message sent from the AMF network element 1. Wherein, the first message carries first indication information, and the first indication information is used for indicating that the AMF network element 1 is to implicitly deregister the terminal 1.

By i.e. to implicitly de-register the terminal 1, it is meant that after a period of time, the AMF network element 1 will perform an implicit de-registration for the terminal 1. The time interval between the sending of the first message and the execution of the implicit de-registration by the AMF network element 1 is not limited in the embodiment of the present application.

Step 709, RAN1 sends a paging message to terminal 1, and terminal 1 receives the paging message from RAN 1. The paging message includes a paging cause. The paging cause indicates that the AMF network element 1 is about to implicitly de-register the terminal 1.

Step 710, the terminal 2 determines to leave the system 2.

In fact, it is assumed that the system to which the terminal leaves its access is ultimately decided by the user, and the decision of the user is implemented only by the terminal. The condition that the terminal 2 determines to leave the system 2 may refer to the condition that the terminal 1 determines to leave the system 1, and is not described herein again.

In step 711, the terminal 2 executes the leaving flow in the system 2.

The implementation of step 711 can refer to the description of steps 701 to 706, which is not described herein again.

The recovery process of the terminal 1 in the system 1 after the terminal 2 leaves the system 2 will be described below with reference to steps 712 to 716 or steps 717 to 718.

In one possible implementation, if the terminal 1 determines that it is not unregistered in the system 1, the terminal 1 performs steps 712 to 716.

Step 712, the terminal 1 sends a registration request message to the AMF network element 1. Accordingly, the AMF network element 1 receives a registration request message from the terminal.

For example, the registration request message may be an initial NAS message. The first message sent by the idle terminal to the AMF network element 1 is used to establish the NAS signaling connection from the terminal to the AMF network element 1. The initial NAS message generally includes a registration request message, a service request message, and the like, and specifically, the initial NAS message is divided into the following scenarios:

scenario 1), if the periodic registration timer has not expired, the initial NAS message may be a service request message or a registration request message. Since the main purpose of the service request message is to change the terminal from an idle state to a connected state, the terminal generally selects to send the service request message. Of course, as an alternative, the terminal 1 may choose to send the registration request message and indicate the registration type as mobile registration update in the registration request message.

Scenario 2), if the periodic registration timer expires, that is, there is an expired record, and any one of the following a) to c) is satisfied, the initial NAS message is a registration request message, and the registration type in the registration request message is indicated as periodic registration update. In this case, the terminal is in a registration state, the terminal may send the service request message, but actually, the terminal has expired, and the terminal needs to negotiate some information with the network side through a registration procedure, so that it is more reasonable to send the registration request message, but sending the service request message may also be used as an alternative.

a) Terminal 1 receives the first time value but the implicit de-registration timer has not expired.

b) The terminal 1 receives the paging message with the indication of the impending implicit de-registration, and the terminal starts to perform the recovery procedure in the system 1 in T1.

c) The terminal 1 does not receive the first time value or the paging message with the indication of the impending implicit de-registration.

For the above cases b) or c), the terminal 1 may not know whether the network has been unregistered accurately, so that the terminal 1 may receive the registration reject message or the service reject message after sending the registration request message or the registration request message and indicate that implicit deregistration has been performed, at this time, steps 713 to 715 are not performed, and this time, the scenario is consistent with the scenario that the terminal 1 is implicitly deregistered, that is, the terminal 1 may perform steps 717 to 718.

Step 713, the AMF network element 1 determines the user plane that needs to activate the session according to the information provided by the terminal 1, and then the AMF network element 1 sends a session update request to the SMF network element 1. Accordingly, the SMF network element 1 receives a session update request from the AMF network element 1. The session update request is used to indicate that a session of the user plane of the terminal 1 needs to be activated.

And 714, the SMF network element 1 interacts with the UPF network element 1 according to the indication of the AMF network element 1 to indicate and activate the user plane of the corresponding session.

For a specific process, reference may be made to descriptions in the prior art, which are not described herein again.

Step 715, after the user plane is activated, the SMF network element 1 sends a session update response to the AMF network element 1, and correspondingly, the AMF network element 1 receives the session update response from the SMF network element 1.

Step 716, the AMF network element 1 sends NAS response message to the terminal 1. The terminal 1 receives the NAS response message from the AMF network element 1.

The NAS response message may be a registration reject message, or a service reject message, if the AMF network element determines that the terminal 1 has been implicitly deregistered in the system 1. The NAS response message may be a service accept message or a registration accept message if the AMF network element determines that the terminal 1 is not implicitly deregistered in the system 1.

In another possible implementation, if the terminal 1 determines to be implicitly unregistered in the system 1, the terminal 1 performs steps 717 to 718.

Step 717, the terminal 1 sends a registration request message to the AMF network element 1, and correspondingly, the AMF network element 1 receives the registration request message from the terminal 1. Wherein, the registration request message indicates that the registration type is initial registration. The terminal 1 performs an initial registration procedure in the following scenario:

1) the terminal 1 receives the first time value and the implicit de-registration timer expires. Or, 2), terminal 1 receives a paging message indicating that implicit de-registration is imminent. The terminal 1 sends the registration request message to the AMF network element 1 after T1, in which case the specific T1 is determined by implementation, which is not limited in this embodiment of the present application.

In step 718, the terminal 1 further needs to establish a session, i.e. executes a session establishment procedure.

The detailed implementation of step 718 can refer to the description in the prior art, and is not described herein again.

In the embodiment shown in fig. 7, the terminal 1 does not need to initiate the periodic registration when the periodic registration timer expires after leaving the system 1, and the terminal 1 can know whether the terminal has been implicitly deregistered, so that the connection in the system 1 can be restored in a suitable manner. In the embodiment shown in fig. 7, the first information is an uplink NAS message, and the first indication is a downlink NAS message.

In the embodiment shown in FIG. 7, steps 702a, 702b, 702c, 702d, 704 and 718 are optional steps.

As shown in fig. 8, fig. 8 describes a specific embodiment of a communication method provided in the embodiment of the present application, and the method is different from the embodiment shown in fig. 7 in that, when the terminal 1 performs registration in the system 1, it negotiates with the AMF network element 1 whether periodic registration is not performed after the terminal 1 leaves the system 1 and enters an idle state in the system 1, and the method includes:

step 801, the terminal 1 sends a registration request message to the AMF network element 1. Accordingly, the AMF network element 1 receives a registration request message from the terminal.

Wherein the registration request message is used to request registration of the terminal 1 in the core network of the system 1.

Optionally, the registration request message includes a suspend period registration indication, where the suspend period registration indication is used to indicate that the terminal 1 expects the terminal 1 to not perform period registration after entering an idle state in the system 1 due to leaving the system 1.

Step 802, the AMF network element 1 sends a registration acceptance message to the terminal 1. The terminal 1 receives a registration accept message from the AMF network element 1.

The registration acceptance message is used to indicate that the AMF network element 1 allows the terminal 1 to leave the system 1 and not perform periodic registration after the state in the system 1 is an idle state.

If the AMF network element 1 allows the terminal 1 not to perform the periodic registration, the registration acceptance message may include permission indication information. The permission indication information is used to indicate that the AMF network element 1 allows the terminal 1 to leave the system 1 and not perform periodic registration after the state in the system 1 is idle.

Optionally, the registration acceptance message includes the first time value.

If the AMF network element 1 does not allow the terminal 1 to perform the periodic registration, the registration acceptance message is used to indicate that the AMF network element 1 does not allow the terminal 1 to perform the periodic registration after the state in the system 1 is the idle state because the terminal leaves the system 1. In one aspect, the registration accept message may include a first field indicating that the AMF network element 1 does not allow the terminal 1 to leave the system 1 and not perform periodic registration after the state in the system 1 is idle. Or the registration accept message may not include: and allowing the indication information to implicitly indicate that the terminal is not allowed to perform periodic registration. The first field may be located in a suspend period registration indication carried in the registration accept message.

Step 803, if the AMF network element 1 determines that the terminal 1 is no longer allowed to perform the periodic registration, the AMF network element 1 sends a configuration update command message to the terminal 1. Accordingly, the terminal 1 receives the configuration update command message from the AMF network element.

Wherein, the configuration updating command message includes a first field.

Step 804, after the terminal 1 receives the configuration update command message from the AMF network element 1, the terminal 1 may send a configuration update completion message to the AMF network element 1.

Step 805, the terminal 1 sends the uplink NAS message to the AMF network element 1, and the AMF network element 1 receives the uplink NAS message from the terminal 1. The upstream NAS message is used to indicate that the terminal 1 is about to leave the system 1.

Step 806 is the same as that described in step 702, and is not described herein again.

In a possible embodiment, as shown in fig. 8, if the registration acceptance message in step 802 does not include the first time value, the method provided in this embodiment may further include:

step 807, the AMF1 sends a downlink NAS message to the terminal 1, and correspondingly, the terminal receives the downlink NAS message from the AMF network element 1. The downlink NAS message includes a first time value.

Step 808 to step 811 are the same as step 704 to step 707 described above, and are not described herein again.

If the AMF network element 1 does not send the first time value to the terminal in both step 802 and step 807, then the AMF network element 1 performs step 812 described below.

Step 812 and synchronization step 708 are not described herein again.

The steps 813 to 822 are the same as the steps 709 to 718 described above.

The embodiment shown in fig. 8 differs from the embodiment shown in fig. 7 in that: when the terminal 1 registers in the core network of the system 1, it indicates to the AMF network element 1 that the terminal 1 wishes to subsequently not perform a periodic registration after the terminal 1 enters an idle state in the system 1 by leaving the system 1. If the AMF network element 1 indicates to the terminal 1 in the registration stage of the terminal 1 that the terminal 1 is allowed to enter the idle state due to leaving the system 1 and then does not perform the periodic registration, the subsequent process of negotiating with the AMF network element 1 to perform the periodic registration may be omitted when the terminal 1 leaves the system 1, so that the terminal 1 may skip the periodic registration when the periodic registration timer expires when the terminal 1 subsequently enters the idle state due to leaving the system 1.

In the embodiment shown in fig. 8, steps 803 to 822 are optional steps.

As shown in fig. 9, fig. 9 differs from fig. 8 and 7 in that: after leaving the system 1, the terminal 1 negotiates with the AMF network element 1 in the system 1 that after leaving the system 1, periodic registration is not performed in the system 1, and the method includes:

step 901, the terminal 1 adopts 3GPP access to register in the system 1 through the USIM card 1.

Step 902a, the terminal 2 registers in the system 2 via the USIM card 2.

In step 902a, the terminal 2 registers in the system 2 with a non-3GPP access or a 3GPP access through the USIM card 2.

The terminal 2 establishes a session in the system 2. The terminal 1 accesses the N3IWF1 of system 1 via the user plane of the session in system 2, that is to say the terminal 1 can re-register with system 1 via non-3GPP access. For example, terminal 1 sends a registration request message to N3IWF1 through the user plane of system 2. In the embodiment of the application, a terminal 1 accesses a system 1 through a USIM card 1, a terminal 2 accesses the system 2 through a USIM card 2, and both the terminal 1 and the terminal 2 access respective systems. Terminal 2 may establish a user plane in system 2, which may be an N3IWF1 in the network to which terminal 1 corresponds, that is, terminal 1 uses the user plane as its non-3GPP access and accesses the network. Corresponding to the terminal 1 accessing the network through non-3GPP access. Of course, the terminal 1 may access the network through the non-3GPP access without using the user plane of the terminal 2.

Step 902b, the terminal 2 establishes a session in the system 2, and the terminal 1 accesses the N3IWF1 network element of the system 1 through the user plane of the session in the system 2.

The terminal 1 can re-register to the system 1 through non-3GPP access through step 902 b.

Step 903, the terminal 2 leaves the system 2.

At this time, the state of the terminal 2 in the system 2 is changed to an IDLE state, and the state of the terminal 1 in the non-3GPP side in the system 1 is an IDLE state, that is, the terminal is in an IDLE state accessed through the non-3GPP (for a 5G system, corresponding english may be 5GMM-IDLE mode over non-3GPP access, and conversely, corresponding english in a CONNECTED state may be 5GMM-CONNECTED mode over non-3GPP access).

It should be noted that, since the terminal 2 forms the non-3GPP access of the terminal 1 in the system 1 in the user plane of the system 2, the state of the terminal 2 in the system 2 changes to the idle state, and the terminal 1 enters the idle state in the non-3 GPP.

Step 904, the terminal 1 executes the recovery flow with the system 1.

The difference between step 905 and step 910 and the above steps 701 to 706 is that: no suspend period registration indication is carried in step 905 and step 907, the AMF network element 1 does not provide the first time value to the terminal 1.

Thereafter, the terminal enters a connected state, i.e., a connected state accessed through non-3GPP, in system 1 (i.e., non-3GPP side), and the terminal enters an IDLE state, i.e., an IDLE state accessed through 3GPP, in system 1 (5GMM-IDLE mode over 3GPP access).

Step 911, the terminal 2 executes the recovery procedure in the system 2.

Step 912, the terminal 1 sends the uplink NAS message to the AMF network element 1 through the non-3GPP access, and correspondingly, the AMF network element 1 receives the uplink NAS message from the terminal through the non-3GPP access. The uplink NAS message may be an uplink NAS message sent in any connection state, and the uplink NAS message includes a suspend period registration instruction.

Step 913, the AMF network element 1 sends the downlink NAS message to the terminal through the non-3GPP access, and correspondingly, the terminal receives the downlink NAS message from the AMF network element 1 through the 3GPP access. The downlink NAS message includes permission indication information. Optionally, the downlink NAS message includes the first time value.

It should be noted that, if the AMF network element 1 determines that the terminal 1 needs to perform the periodic registration after entering the idle state in the system 1 due to leaving the system 1, the downlink NAS message is used to indicate that the terminal 1 does not allow the terminal 1 to perform the periodic registration after entering the idle state due to leaving the system 1, or the downlink NAS message does not include the permission indication information.

If the AMF network element 1 does not send the first time value to the terminal in step 913, the AMF network element 1 may further perform step 914 described below before preparing to perform implicit de-registration for the terminal.

Step 914, the AMF network element 1 may send the NAS notification message to the terminal 1 through the non-3GPP access, and correspondingly, the terminal 1 receives the NAS notification message from the AMF network element 1 through the non-3GPP access. The NAS notification message is used to indicate that implicit de-registration of the terminal 1 is imminent.

The descriptions of step 915 to step 923 and the descriptions of the synchronization step 710 to step 718 are omitted here for brevity.

The embodiment shown in fig. 9 differs from the embodiment shown in fig. 7 in that: in fig. 9, after the terminal 1 leaves the system 1, it is negotiated with the AMF network element 1 in the system 1 whether the terminal 1 is allowed to perform the non-periodic registration. In the embodiment shown in fig. 7, when the terminal 1 is ready to leave the system 1, it negotiates with the AMF network element 1 in the system 1 whether the terminal 1 is allowed to perform non-periodic registration.

In the embodiment shown in fig. 9, steps 901 to 911 and steps 914 to 923 are optional steps.

As shown in fig. 10, a specific embodiment of a communication method provided in the embodiment of the present application is described, and the method is different from the embodiment shown in fig. 9 in that the method includes:

steps 1001 to 1006 are the same as steps 701 to 706, except that: step 1001 does not carry a suspend period registration indication. The first time value is not carried in step 1003.

Step 1007a, the terminal 1 sends a suspend period registration indication to a network element or device (e.g. paging server) through the user plane of the system 2.

For example, the terminal 1 sends a suspend period registration to a network element or device (e.g., a paging server) of the system 1 via a user of the system 2.

Step 1007b, the network element or device (e.g., paging server) sends a message to the AMF network element 1, which includes a suspend period registration indication.

Step 1008a, the AMF network element 1 sends a response message to the paging server, and correspondingly, the paging server receives the response message from the AMF network element 1. The response message includes a suspend period registration instruction, where the suspend period registration instruction is used to instruct the AMF network element 1 to allow the terminal not to perform periodic registration. Optionally, the response message includes the first time value.

If the AMF network element 1 does not allow the terminal to not perform the periodic registration, the response message includes indication information for indicating that the terminal is not allowed to perform the periodic registration, or does not include a suspend periodic registration indication.

Step 1008b, the paging server sends the received response message to the terminal 1 through the user plane of the system 2.

When the terminal 1 is in an idle state in the system 1 due to leaving the system 1, the core network and the terminal 1 may send signaling through the paging server. For example, when the AMF network element 1 determines that downlink data needs to page the terminal 1, the AMF network element 1 may send paging content to a paging server, and the paging server sends the paging content to the terminal 1 through the user plane of the system 2.

As a possible embodiment, if the step 1008 does not include the first time value, as shown in fig. 10, the method provided by the embodiment of the present application may further include, after the step 1008:

step 1009, the AMF network element 1 sends the notification message to the terminal 1 through the paging server, and accordingly, the terminal 1 may receive the notification message from the AMF network element 1 through the paging server. The notification message indicates that the terminal 1 is to be implicitly registered.

Step 1010 to step 1018, and step 711 to step 718, which are not described herein again.

In the embodiments shown in fig. 7 to 10, the terminal 1 may be the first terminal described above.

It should be noted that, in the embodiment of the present application, all the actions performed by the AMF network element may be performed by the MME, in other words, the AMF network element may be replaced by the MME.

In the embodiment shown in fig. 10, steps 1001 to 1006 and steps 1009a to 1018 are optional steps.

The above-mentioned scheme of the embodiment of the present application is introduced mainly from the perspective of interaction between network elements. It will be appreciated that the respective network elements, such as the first terminal and the first AMF network element, etc., for implementing the above-described functions, include corresponding structures and/or software modules for performing the respective functions. Those of skill in the art will readily appreciate that the present application is capable of hardware or a combination of hardware and computer software implementing the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein. 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 first terminal and the first AMF network element may perform functional unit division according to the above method, for example, each functional unit may be divided corresponding to each function, or two or more functions may be integrated in one processing unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit. It should be noted that the division of the unit in the embodiment of the present application is schematic, and is only a logic function division, and there may be another division manner in actual implementation.

The method of the embodiment of the present application is described above with reference to fig. 5 to 10, and a communication apparatus provided in the embodiment of the present application for performing the method is described below. Those skilled in the art will understand that the method and the apparatus may be mutually combined and referred, and the communication apparatus provided in the embodiments of the present application may perform the steps performed by the first terminal and the first AMF network element in the analysis method described above.

In the case of employing an integrated unit, fig. 11 shows a communication apparatus as referred to in the above-described embodiment, which may include: a communication module 1113 and a processing module 1112.

In an alternative implementation, the communication device may further include a storage module 1111 for storing program codes and data of the communication device.

In one example, the communication device is a first terminal or a chip applied in the first terminal. In this case, the communication module 1113 is used to support the communication device to communicate with an external network element (e.g., an AMF network element). For example, the communication module 1113 is configured to perform the signal transceiving operation of the first terminal in the above method embodiment. The processing module 1112 is configured to perform the signal processing operation of the first terminal in the above method embodiment.

In one embodiment of the present application, the communication module 1113 is configured to perform the sending action performed by the first terminal in step 501 and the receiving action performed by the first terminal in step 502 in fig. 5 of the foregoing embodiments. A processing module 1112 configured to enable the communication apparatus to perform step 503 of the steps of fig. 5.

For another example, in another embodiment of the present application, the communication module 1113 is configured to execute the sending action performed by the first terminal in step 601a or step 601b or step 612 of fig. 6a of the foregoing embodiments, and the receiving action performed by the first terminal in step 602a, step 602b, and step 611 a. A processing module 1112, configured to enable the communication apparatus to perform step 603, step 604a, step 605a, and step 606a of fig. 6 a.

Alternatively, in another embodiment of the present application, the communication module 1113 is configured to execute the sending action performed by the first terminal in step 601a or step 601b or step 610b of fig. 6b and the receiving action performed by the first terminal in step 602a and step 609b of the above embodiments. A processing module 1112, configured to support the communication apparatus to perform step 603, step 606b, and step 607b of fig. 6 b.

In another example, the communication device is an AMF network element or a chip applied in the AMF network element. In this case, the communication module 1113 is used to support the communication device to communicate with an external network element (e.g., a first terminal). For example, the communication module 1113 is configured to perform the signal transceiving operation of the AMF network element in the foregoing method embodiment. The processing module 1112 is configured to perform the signal processing operation of the AMF network element in the foregoing method embodiment.

In one aspect, in an embodiment of the present application, the communication module 1113 is configured to perform the receiving action performed by the AMF network element in step 501 and the sending action performed by the AMF network element in step 502 in fig. 5 of the foregoing embodiments. A processing module 1112 configured to enable the communication device to perform the processing actions performed by the AMF network element.

For another example, in another embodiment of the present application, the processing module 1112 is configured to perform steps 607a to 609a of fig. 6a of the foregoing embodiment. The communication module 1113 is further configured to perform the sending action performed by the AMF network element in step 610a of fig. 6a of the foregoing embodiment. The communication module 1113 is further configured to perform the actions of receiving performed by the AMF network element in step 612 of fig. 6a of the foregoing embodiments.

For another example, in an embodiment of the present application, the processing module 1112 is configured to perform steps 604b to 605ba of fig. 6b of the foregoing embodiment. The communication module 1113 is further configured to perform the sending action performed by the AMF network element in step 608b of fig. 6b in the foregoing embodiment. The communication module 1113 is further configured to perform the actions of receiving performed by the AMF network element in step 610b of fig. 6b of the foregoing embodiment.

The processing module 1112 may be a processor or controller, such as a central processing unit, general purpose processor, digital signal processor, application specific integrated circuit, field programmable gate array or other programmable logic device, transistor logic device, hardware component, or any combination thereof. Which may implement or perform the various illustrative logical blocks, modules, and circuits described in connection with the disclosure. A processor may also be a combination of computing functions, e.g., a combination of one or more microprocessors, a digital signal processor and a microprocessor, or the like. The communication module may be a transceiver, a transceiving circuit or a communication interface, etc. The storage module may be a memory.

When the processing module 1112 is the processor 1201 or the processor 1205, the communication module 1113 is the communication interface 1203, and the storage module 1111 is the memory 1202, the communication apparatus according to the present application may be the communication device shown in fig. 12.

Fig. 12 is a schematic diagram illustrating a hardware structure of a communication device according to an embodiment of the present application. The structures of the first terminal and the AMF network element in the embodiment of the present application may refer to a schematic structural diagram of a communication device shown in fig. 12. The communication device includes a processor 1201, a communication line 1204, and at least one communication interface (an example of which is illustrated in fig. 12 by way of a communication interface 1203).

The processor 1201 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 teachings of the present application.

The communication link 1204 may include a path to transmit information between the aforementioned components.

The communication interface 1203 is used for information interaction with other devices, for example, any transceiver or other devices, and is used for communication with other devices or communication networks, such as ethernet, Radio Access Network (RAN), Wireless Local Area Network (WLAN), and so on.

Optionally, the communication device may also include memory 1202.

The memory 1202 may be 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 disc storage, optical disc storage (including compact disc, laser disc, optical disc, digital versatile disc, blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer, but is not limited to such. The memory may be separate and coupled to the processor via a communication line 1204. The memory may also be integral to the processor.

The memory 1202 is used for storing computer-executable instructions for executing the present invention, and is controlled by the processor 1201 to execute. The processor 1201 is configured to execute computer-executable instructions stored in the memory 1202 to implement a communication 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 1201 may include one or more CPUs such as CPU0 and CPU1 in fig. 12, for example, as an example.

In particular implementations, a communication device may include multiple processors, such as processor 1201 and processor 1205 in fig. 12, 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).

The steps performed by the processor 1201 and the processor 1205 may refer to the steps performed by the processing module 1112 described above. The steps performed by the communication interface 1203 may refer to the steps performed by the communication module 1113 described above.

It is to be noted that when the communication device shown in fig. 12 is a first terminal, the communication interface 1203 may be replaced with a transceiver.

Fig. 13 is a schematic structural diagram of a chip 130 according to an embodiment of the present disclosure. Chip 130 includes one or more (including two) processors 1310 and a communication interface 1330.

Optionally, the chip 130 further includes a memory 1340, which may include both read-only memory and random access memory 1340, and provides operating instructions and data to the processor 1310. A portion of memory 1340 may also include non-volatile random access memory (NVRAM).

In some embodiments, memory 1340 stores elements, execution modules or data structures, or a subset thereof, or an expanded set thereof.

In the embodiment of the present application, by calling an operation instruction stored in the memory 1340 (the operation instruction may be stored in the operation system), a corresponding operation is performed.

One possible implementation is: the first terminal and the AMF network element have similar structures, and different devices may use different chips to implement their respective functions.

The processor 1310 controls processing operations of any one of the first terminal and the AMF network element, and the processor 1310 may also be referred to as a Central Processing Unit (CPU).

Memory 1340 may include both read-only memory and random-access memory and provides instructions and data to processor 1310. A portion of memory 1340 may also include NVRAM. For example, in applications where memory 1340, communication interface 1330, and memory 1340 are coupled together by bus system 1320, where bus system 1320 may include a power bus, a control bus, and a status signal bus, among others, in addition to a data bus. For clarity of illustration, however, the various buses are labeled as bus system 1320 in fig. 13.

The method disclosed in the embodiments of the present application may be applied to the processor 1310, or implemented by the processor 1310. The processor 1310 may be an integrated circuit chip having signal processing capabilities. In implementation, the steps of the above method may be performed by integrated logic circuits of hardware or instructions in the form of software in the processor 1310. The processor 1310 may be a general purpose processor, a Digital Signal Processor (DSP), an ASIC, an off-the-shelf programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, or discrete hardware components. The various methods, steps, and logic blocks disclosed in the embodiments of the present application may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of the method disclosed in connection with the embodiments of the present application may be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software modules in the decoding processor. The software modules may be located in random access memory, flash memory, read only memory, programmable read only memory or electrically erasable programmable memory, registers, or other storage media as is known in the art. The storage medium is located in the memory 1340, and the processor 1310 reads the information in the memory 1340, and combines the hardware to complete the steps of the above-mentioned method.

In one possible implementation, the communication interface 1330 is configured to perform the steps of receiving and transmitting by the first terminal in the embodiments shown in fig. 5-10. The processor 1310 is configured to execute the steps of the processing of the first terminal in the embodiments shown in fig. 5-10.

In one possible implementation, communication interface 1330 is configured to perform the steps of receiving and transmitting AMF cells in the embodiments illustrated in fig. 5-10. The processor 1310 is configured to perform the steps of the AMF network element process in the embodiments shown in fig. 5 to 10.

In one aspect, a computer-readable storage medium is provided, in which instructions are stored, and when the instructions are executed, the functions performed by the first terminal in fig. 5 to 10 are implemented.

In one aspect, a computer program product comprising instructions is provided, the computer program product comprising instructions that, when executed, implement the functions performed by the AMF network element as in fig. 5-10.

In one aspect, a chip is provided, where the chip is applied to a first terminal, and the chip includes at least one processor and a communication interface, where the communication interface is coupled to the at least one processor, and the processor is configured to execute instructions to implement functions performed by the first terminal in fig. 5 to fig. 10.

In one aspect, a chip is provided, where the chip is applied in a first terminal, and the chip includes at least one processor and a communication interface, where the communication interface is coupled to the at least one processor, and the processor is configured to execute instructions to implement the functions performed by the AMF network element in fig. 5 to 10.

An embodiment of the present application provides a communication system, including: a first terminal and an AMF network element. Wherein the first terminal is configured to perform the functions performed by the first terminal in fig. 5 to 10, and the AMF network element is configured to perform the functions performed by the AMF network element in fig. 5 to 10.

In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are performed in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, a network appliance, a user device, or other programmable apparatus. The computer program or instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer program or instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wire or wirelessly. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that integrates one or more available media. The usable medium may be a magnetic medium, such as a floppy disk, hard disk, magnetic tape; or optical media such as Digital Video Disks (DVDs); it may also be a semiconductor medium, such as a Solid State Drive (SSD).

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 modifications and variations can 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 also intended to include such modifications and variations.

Claims

1. A method of communication, comprising:

an access and mobility management (AMF) network element in a first system receives first information from a first terminal, wherein equipment where the first terminal is located is provided with a plurality of global user identification cards, the first terminal corresponds to a first global user identification card in the plurality of global user identification cards, and the first system is a system accessed by the first terminal;

and the AMF network element sends a first indication to the first terminal according to the first information, wherein the first indication allows the first terminal not to perform periodic registration after entering an idle state in the first system.

2. The method of claim 1,

the first indication indicates that the first terminal is allowed to enter an idle state due to leaving the first system and then does not perform periodic registration.

3. The method according to claim 1 or 2, characterized in that the method further comprises:

and the AMF network element determines to allow the first terminal not to perform periodic registration after the first terminal enters an idle state in the first system according to the first information.

4. The method according to any one of claims 1 to 3, wherein the first information includes a suspend period registration indication, and the suspend period registration indication is used to indicate that the first terminal desires not to perform period registration after entering an idle state in the first system;

alternatively, the first and second electrodes may be,

the first information comprises a second indication indicating that the first terminal will leave the first system.

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

and the AMF network element sends a first time value to the first terminal, wherein the first time value is used for indicating the duration of a first timer for implicit de-registration of the first terminal in the first system.

6. The method of claim 5, further comprising:

and when the first terminal is changed from a connection state to an idle state in the AMF network element, the AMF network element skips the starting of the mobile reachable timer.

7. The method of claim 5 or 6, further comprising:

and when the first terminal is changed from a connection state to an idle state in the AMF network element, the AMF network element starts an implicit de-registration timer, wherein the duration of the implicit de-registration timer is greater than the first time value.

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

at a first time, the AMF network element starts a timer, where the timer is used to record a duration that the first terminal enters an idle state in the first system, and the first time is a time when a connection state of the first terminal in the AMF network element changes from a connection state to an idle state;

and when the time length of the first terminal is greater than or equal to a second time value, the AMF network element performs implicit de-registration on the first terminal in the first system.

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

when the first terminal is in an idle state in the first system, the AMF network element sends a first message to an access network, where the first message is used to request the access network to page the first terminal, and indicates in a paging message that the AMF network element is to perform implicit de-registration on the first terminal.

10. A method of communication, comprising:

a first terminal sends first information to an access and mobility management (AMF) network element in a first system, wherein the first information is used for the AMF network element to determine whether the first terminal is allowed to enter an idle state in the first system and then does not perform periodic registration, equipment where the first terminal is located is provided with a plurality of global user identification cards, the first terminal corresponds to a first global user identification card in the plurality of global user identification cards, and the first system is a system accessed by the first terminal;

and the first terminal receives a first indication from the AMF network element, wherein the first indication is used for indicating that the first terminal is allowed not to perform periodic registration after entering an idle state in the first system.

11. The method of claim 10,

12. The method according to claim 10 or 11, wherein the first information includes a suspend period registration indication, and the suspend period registration indication is used to indicate that the first terminal desires not to perform period registration after entering the idle state in the first system; alternatively, the first and second electrodes may be,

13. The method of any one of claims 10 to 12, further comprising:

and the first terminal receives a first time value from the AMF network element, wherein the first time value is used for indicating the duration of a first timer for implicit de-registration of the first terminal in the first system.

14. The method of claim 13, further comprising:

at a second time, the first terminal starts a third timer and a first timer, where the value of the first timer is the first time value, and the second time is a time when the state of the first terminal in the AMF network element changes from a connected state to an idle state;

when the third timer expires, the first terminal skips the process of executing periodic registration, but saves an expired record;

when the first timer expires, the first terminal performs implicit de-registration in the first system.

15. The method of any one of claims 10 to 14, further comprising:

starting a third timer by the first terminal at a second moment, where the second moment is a moment when the state of the first terminal in the AMF network element changes from a connected state to an idle state;

and when the third timer expires, the first terminal skips the process of performing the periodic registration, but saves an expired record of the periodic registration.

16. The method of any one of claims 10 to 15, further comprising:

and the first terminal receives a paging message from an access network, wherein the paging message is used for indicating that the AMF network element performs implicit de-registration on the first terminal.

17. A communication apparatus, the apparatus being used in a first system, the apparatus comprising:

the communication unit is used for receiving first information from a first terminal, the equipment where the first terminal is located is provided with a plurality of global user identification cards, the first terminal corresponds to a first global user identification card in the plurality of global user identification cards, and the first system is a system accessed by the first terminal;

and the processing unit is used for sending a first instruction to the first terminal through the communication unit according to the first information, wherein the first instruction allows the first terminal not to perform periodic registration after entering an idle state in the first system.

18. The apparatus according to claim 17 or 19, wherein the first indication indicates that the first terminal is allowed to enter an idle state due to leaving the first system without periodic registration.

19. The apparatus according to any of claims 17 to 18, wherein the processing unit is further configured to determine, according to the first information, that the first terminal is allowed to enter an idle state in the first system without performing periodic registration.

20. The apparatus according to any of claims 17 to 19, wherein the first information comprises a suspend period registration indication, and the suspend period registration indication is used to indicate that the first terminal desires not to perform period registration after entering an idle state in the first system;

alternatively, the first and second electrodes may be,

21. The apparatus according to any of claims 17 to 20, wherein the communication unit is further configured to send a first time value to the first terminal, and the first time value is used to indicate a first timer duration for implicit de-registration of the first terminal in the first system.

22. The apparatus of claim 21,

and when the first terminal changes from a connection state to an idle state in the device, the processing unit is used for skipping the starting of the mobile reachable timer.

23. The apparatus of claim 21 or 22,

when the first terminal changes from a connection state to an idle state in the device, the processing unit is further configured to start an implicit deregistration timer, where a duration of the implicit deregistration timer is greater than the first time value.

24. The apparatus according to any one of claims 17 to 20,

at a first time, the processing unit is further configured to start a timer, where the timer is configured to record a duration that the first terminal enters an idle state in the first system, and the first time is a time at which a connection state of the first terminal in the apparatus changes from a connection state to an idle state;

and when the duration of the first terminal is greater than or equal to the second time value, the processing unit is further configured to perform implicit de-registration on the first terminal in the first system.

25. The apparatus according to any one of claims 17 to 20,

the communication unit is further configured to send a first message to an access network when the first terminal is in an idle state in the first system, where the first message is used to request the access network to page the first terminal, and indicate in a paging message that the apparatus is to perform implicit de-registration for the first terminal.

26. A communication apparatus, wherein the apparatus is a first terminal or a chip applied in the first terminal, the apparatus comprising: the system comprises a communication unit and a processing unit, wherein the processing unit is used for processing information, and the communication unit is used for receiving or sending information;

the communication unit is configured to send first information to an access and mobility management AMF network element in a first system, where the first information is used for the AMF network element to determine whether to allow the first terminal to enter an idle state in the first system and then not perform periodic registration, a device where the first terminal is located has multiple global subscriber identity cards, the first terminal corresponds to a first global subscriber identity card in the multiple global subscriber identity cards, and the first system is a system to which the first terminal is accessed;

the communication unit is further configured to receive a first indication from the AMF network element, where the first indication is used to indicate that the first terminal is allowed not to perform periodic registration after entering an idle state in the first system.

27. The apparatus of claim 26, wherein the first information comprises a suspend period registration indication, and wherein the suspend period registration indication indicates that the first terminal desires that the first terminal not perform period registration after entering an idle state in the first system; alternatively, the first and second electrodes may be,

28. The apparatus according to any of claims 26 to 27, wherein the communications unit is further configured to receive a first time value from the AMF network element, where the first time value is used to indicate a first timer duration for implicit de-registration of the first terminal in the first system.

29. The apparatus of claim 28,

at a second time, the processing unit is further configured to start a third timer and a first timer, where a value of the first timer is the first time value, and the second time is a time when a state of the first terminal in the AMF network element changes from a connected state to an idle state;

when the third timer expires, the processing unit is configured to skip a process of performing periodic registration, but save an expired record;

the processing unit is further configured to perform implicit de-registration in the first system when the first timer expires.

30. The apparatus of any one of claims 26 to 29,

at a second time, the processing unit is further configured to start a third timer, where the second time is a time when the state of the first terminal in the AMF network element changes from a connected state to an idle state;

when the third timer expires, the processing unit is configured to skip the process of performing the periodic registration, but save an expired record of the periodic registration.

31. The apparatus according to any of claims 26 to 29, wherein the communication unit is further configured to receive a paging message from an access network, and the paging message is used to indicate that the AMF network element is to perform implicit de-registration for the first terminal.

32. A computer-readable storage medium having stored thereon instructions which, when executed, implement the method of any of claims 1 to 9 or the method of any of claims 10 to 16.

33. A chip, wherein the chip comprises: a processor coupled to a communication interface for running a computer program or instructions to implement the method of any of claims 1 to 9 or the method of any of claims 10 to 16, the communication interface for communicating with other modules than the chip.